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These are the user uploaded subtitles that are being translated: 1 00:00:14,760 --> 00:00:16,520 Our ancestors understood 2 00:00:16,520 --> 00:00:18,760 origins by extrapolating from 3 00:00:18,760 --> 00:00:20,200 their own experience. 4 00:00:20,200 --> 00:00:22,600 How else could they have done it? 5 00:00:22,600 --> 00:00:24,320 So, the universe was hatched 6 00:00:24,320 --> 00:00:25,520 from a cosmic egg, 7 00:00:25,520 --> 00:00:27,680 or conceived in the sexual 8 00:00:27,680 --> 00:00:29,080 congress of a mother god and 9 00:00:29,080 --> 00:00:29,960 a father god, 10 00:00:30,560 --> 00:00:32,040 or was a kind of product of 11 00:00:32,040 --> 00:00:33,520 the creator's workshop, 12 00:00:33,520 --> 00:00:34,640 perhaps the latest of many 13 00:00:34,640 --> 00:00:36,840 flawed attempts. 14 00:00:36,840 --> 00:00:38,120 And the universe was not much 15 00:00:38,120 --> 00:00:39,680 bigger than we see, 16 00:00:39,680 --> 00:00:40,800 and not much older than our 17 00:00:40,800 --> 00:00:42,760 written or oral records, 18 00:00:42,760 --> 00:00:43,840 and nowhere very different 19 00:00:43,840 --> 00:00:46,560 from places that we know. 20 00:00:46,560 --> 00:00:47,560 We've tended in our 21 00:00:47,560 --> 00:00:50,520 cosmologies to make things familiar. 22 00:00:50,520 --> 00:00:52,440 Despite all our best efforts, 23 00:00:52,440 --> 00:00:54,640 we've not been very inventive. 24 00:00:54,640 --> 00:00:56,960 In the West, heaven is placid 25 00:00:56,960 --> 00:00:58,440 and fluffy, 26 00:00:58,440 --> 00:01:00,200 and hell is like the inside 27 00:01:00,200 --> 00:01:02,040 of a volcano. 28 00:01:02,040 --> 00:01:03,520 In many stories, both realms 29 00:01:03,520 --> 00:01:06,160 are governed by dominance hierarchies, 30 00:01:06,160 --> 00:01:08,640 headed by gods or devils. 31 00:01:08,640 --> 00:01:10,360 Monotheists talked about the 32 00:01:10,360 --> 00:01:11,360 king of kings. 33 00:01:11,360 --> 00:01:13,120 things. In every culture, we 34 00:01:13,120 --> 00:01:14,360 imagined something like our 35 00:01:14,360 --> 00:01:15,680 own political system running 36 00:01:15,680 --> 00:01:17,240 the universe. 37 00:01:17,240 --> 00:01:21,080 Few found the similarity suspicious. 38 00:01:21,080 --> 00:01:22,240 Then science came along and 39 00:01:22,240 --> 00:01:22,760 taught us that 40 00:01:22,760 --> 00:01:23,720 we are not the measure of 41 00:01:23,720 --> 00:01:25,400 all things, that there are 42 00:01:25,400 --> 00:01:27,920 wonders unimagined, that the universe 43 00:01:27,920 --> 00:01:29,600 is not obliged to conform to 44 00:01:29,600 --> 00:01:31,120 what was considered comfortable 45 00:01:31,120 --> 00:01:33,080 or plausible. 46 00:01:33,080 --> 00:01:34,060 And again, if we 47 00:01:34,060 --> 00:01:35,280 are not important, not 48 00:01:35,280 --> 00:01:36,880 central, not the apple of 49 00:01:36,880 --> 00:01:38,960 God's eye, what is implied 50 00:01:38,960 --> 00:01:40,200 for our theologically 51 00:01:40,200 --> 00:01:42,760 based moral codes. 52 00:01:42,760 --> 00:01:44,120 The discovery of our true 53 00:01:44,120 --> 00:01:46,160 bearings in the cosmos was resisted 54 00:01:46,160 --> 00:01:47,480 for so long and to such a 55 00:01:47,480 --> 00:01:49,760 degree that many traces of 56 00:01:49,760 --> 00:01:52,000 the debate remain, 57 00:01:52,000 --> 00:01:53,200 sometimes with the motives of 58 00:01:53,200 --> 00:01:57,240 the geocentrists laid bare. 59 00:01:57,240 --> 00:01:58,320 So what do we 60 00:01:58,320 --> 00:01:59,520 really want from philosophy 61 00:01:59,520 --> 00:02:01,120 and religion? 62 00:02:01,120 --> 00:02:02,680 Palliatives? 63 00:02:02,680 --> 00:02:04,280 Therapy? Comfort? Do we want 64 00:02:04,280 --> 00:02:06,440 reassuring fables or an 65 00:02:06,440 --> 00:02:07,400 understanding of our 66 00:02:07,400 --> 00:02:09,800 actual circumstances? 67 00:02:09,800 --> 00:02:10,640 Dismay that the 68 00:02:10,640 --> 00:02:12,280 universe does not conform to 69 00:02:12,280 --> 00:02:15,400 our preferences seems childish. 70 00:02:15,400 --> 00:02:16,520 You might think that grown-ups 71 00:02:16,520 --> 00:02:17,960 would be ashamed to put such 72 00:02:17,960 --> 00:02:19,560 disappointments into print. 73 00:02:19,560 --> 00:02:20,920 The fashionable way of doing 74 00:02:20,920 --> 00:02:22,480 this is not to blame the 75 00:02:22,480 --> 00:02:25,680 universe, which seems truly pointless, 76 00:02:25,680 --> 00:02:26,920 but rather to blame the means 77 00:02:26,920 --> 00:02:27,680 by which we know the 78 00:02:27,680 --> 00:02:31,600 universe, namely science. 79 00:02:31,600 --> 00:02:34,120 Science has taught us that 80 00:02:34,120 --> 00:02:35,320 because we have a talent for 81 00:02:35,320 --> 00:02:38,080 deceiving ourselves, subjectivity 82 00:02:38,080 --> 00:02:40,640 may not freely reign. 83 00:02:40,640 --> 00:02:42,000 Its conclusions derive from 84 00:02:42,000 --> 00:02:44,080 the interrogation of nature, 85 00:02:44,080 --> 00:02:46,280 and are not in all cases pre-designed 86 00:02:46,280 --> 00:02:49,240 to satisfy our wants. 87 00:02:49,240 --> 00:02:51,000 We recognize that even revered 88 00:02:51,000 --> 00:02:52,760 religious leaders, the products 89 00:02:52,760 --> 00:02:55,400 of their time, as we are of ours, 90 00:02:55,400 --> 00:02:57,400 may have made mistakes. 91 00:02:57,400 --> 00:02:59,880 Religions contradict one another. 92 00:02:59,880 --> 00:03:02,760 On small matters, such as 93 00:03:02,760 --> 00:03:03,680 whether we should put on a 94 00:03:03,680 --> 00:03:05,480 hat or take one off on entering a 95 00:03:05,480 --> 00:03:07,600 house of worship, or whether 96 00:03:07,600 --> 00:03:09,600 we should eat beef and eschew 97 00:03:09,600 --> 00:03:12,280 pork or the other way around, 98 00:03:12,280 --> 00:03:13,200 all the way to the most 99 00:03:13,200 --> 00:03:14,520 central issues such as whether 100 00:03:14,520 --> 00:03:16,840 there are no gods, one god, 101 00:03:16,840 --> 00:03:20,000 or many gods. 102 00:03:20,000 --> 00:03:21,040 If you lived two or three 103 00:03:21,040 --> 00:03:22,960 millennia ago, there was no 104 00:03:22,960 --> 00:03:24,600 shame in holding that the universe 105 00:03:24,600 --> 00:03:26,200 was made for us. 106 00:03:26,200 --> 00:03:27,560 It was an appealing thesis 107 00:03:27,560 --> 00:03:29,520 consistent with everything we knew. 108 00:03:29,520 --> 00:03:30,920 It was what the most learned 109 00:03:30,920 --> 00:03:34,560 among us taught without qualification. 110 00:03:34,560 --> 00:03:36,480 But we've found out much since then. 111 00:03:36,480 --> 00:03:37,760 Defending such a position 112 00:03:37,760 --> 00:03:39,640 today amounts to willful 113 00:03:39,640 --> 00:03:41,560 disregard of the evidence and 114 00:03:41,560 --> 00:03:44,400 a flight from self-knowledge. 115 00:03:44,400 --> 00:03:46,240 We long to be here for a 116 00:03:46,240 --> 00:03:48,760 purpose, even though, despite 117 00:03:48,760 --> 00:03:52,520 much self-deception, none is evident. 118 00:03:52,520 --> 00:03:54,480 Our time is burdened under 119 00:03:54,480 --> 00:03:55,760 the cumulative weight of 120 00:03:55,760 --> 00:03:59,800 successive debunkings of our conceits. 121 00:03:59,800 --> 00:04:01,640 We are Johnny-come-latelys. 122 00:04:01,640 --> 00:04:04,280 We live in the cosmic boondocks. 123 00:04:04,280 --> 00:04:06,840 We emerged from microbes and muck. 124 00:04:06,840 --> 00:04:08,960 Apes are our cousins. 125 00:04:08,960 --> 00:04:10,120 Our thoughts and feelings are 126 00:04:10,120 --> 00:04:12,640 not fully under our own control. 127 00:04:12,640 --> 00:04:13,920 There may be much smarter and 128 00:04:13,920 --> 00:04:14,720 very different beings 129 00:04:14,720 --> 00:04:16,600 elsewhere, and on top of all this, 130 00:04:16,600 --> 00:04:17,760 we are making a mess of our 131 00:04:17,760 --> 00:04:19,680 planet and becoming a danger 132 00:04:19,680 --> 00:04:21,880 to ourselves. 133 00:04:21,880 --> 00:04:24,480 The trapdoor beneath our feet 134 00:04:24,480 --> 00:04:26,320 swings open. 135 00:04:26,320 --> 00:04:28,200 We find ourselves in 136 00:04:28,200 --> 00:04:29,720 bottomless freefall. 137 00:04:30,960 --> 00:04:32,240 We are lost in a great 138 00:04:32,240 --> 00:04:34,200 darkness, and there's no one 139 00:04:34,200 --> 00:04:36,920 to send out a search party. 140 00:04:36,920 --> 00:04:39,200 Given so harsh a reality, of 141 00:04:39,200 --> 00:04:40,600 course we're tempted to shut 142 00:04:40,600 --> 00:04:42,520 our eyes and pretend that 143 00:04:42,520 --> 00:04:44,080 we're safe and snug at home, 144 00:04:44,080 --> 00:04:47,280 that the fall is only a bad dream. 145 00:04:47,280 --> 00:04:48,880 Once we overcome our fear of 146 00:04:48,880 --> 00:04:50,360 being tiny, 147 00:04:50,360 --> 00:04:51,600 We find ourselves on the 148 00:04:51,600 --> 00:04:53,320 threshold of a vast and 149 00:04:53,320 --> 00:04:55,440 awesome universe that utterly 150 00:04:55,440 --> 00:04:58,080 dwarfs, in time, in space, 151 00:04:58,080 --> 00:05:00,360 and in potential, the tidy 152 00:05:00,360 --> 00:05:01,520 anthropocentric 153 00:05:01,520 --> 00:05:04,760 proscenium of our ancestors. 154 00:05:04,760 --> 00:05:06,280 We gaze across billions of 155 00:05:06,280 --> 00:05:07,920 light-years of space 156 00:05:07,920 --> 00:05:09,280 to view the universe shortly 157 00:05:09,280 --> 00:05:11,640 after the Big Bang and plumb 158 00:05:11,640 --> 00:05:13,640 the fine structure of matter. 159 00:05:13,640 --> 00:05:14,840 We peer down into the 160 00:05:14,840 --> 00:05:16,240 core of our planet and the 161 00:05:16,240 --> 00:05:19,080 blazing interior of our star. 162 00:05:19,080 --> 00:05:20,120 We read the genetic 163 00:05:20,120 --> 00:05:21,880 language in which is written 164 00:05:21,880 --> 00:05:24,520 the diverse skills and propensities 165 00:05:24,520 --> 00:05:26,680 of every being on Earth. 166 00:05:26,680 --> 00:05:28,280 We uncover hidden chapters in 167 00:05:28,280 --> 00:05:29,640 the record of our own origins. 168 00:05:30,360 --> 00:05:31,640 We invent and refine 169 00:05:31,640 --> 00:05:33,040 agriculture, without which 170 00:05:33,040 --> 00:05:35,560 almost all of us would starve to death. 171 00:05:35,560 --> 00:05:36,880 We create medicines and 172 00:05:36,880 --> 00:05:38,560 vaccines that save the lives 173 00:05:38,560 --> 00:05:40,080 of billions. 174 00:05:40,080 --> 00:05:41,320 We communicate at the speed 175 00:05:41,320 --> 00:05:42,520 of light and whip around the 176 00:05:42,520 --> 00:05:44,480 Earth in an hour and a half. 177 00:05:44,480 --> 00:05:46,120 We have sent dozens of ships 178 00:05:46,120 --> 00:05:46,720 to more than 179 00:05:46,720 --> 00:05:48,680 seventy worlds and four 180 00:05:48,680 --> 00:05:51,080 spacecraft to the stars. 181 00:05:51,080 --> 00:05:52,560 To our ancestors, there was 182 00:05:52,560 --> 00:05:53,800 much in nature to be afraid 183 00:05:53,800 --> 00:05:57,520 of—lightning, storms, Earthquakes, 184 00:05:57,520 --> 00:05:59,640 volcanoes, plagues, drought, 185 00:06:00,320 --> 00:06:02,280 long winters. 186 00:06:02,280 --> 00:06:03,680 Religions arose in part as 187 00:06:03,680 --> 00:06:05,520 attempts to propitiate and 188 00:06:05,520 --> 00:06:08,840 control, if not much to understand, the 189 00:06:08,840 --> 00:06:12,000 disorderly aspect of nature. 190 00:06:12,000 --> 00:06:13,920 How much more satisfying had 191 00:06:13,920 --> 00:06:15,440 we been placed in a garden 192 00:06:15,440 --> 00:06:17,760 custom-made for us, its other 193 00:06:17,760 --> 00:06:19,160 occupants put there for us to 194 00:06:19,160 --> 00:06:21,720 use as we saw fit? 195 00:06:21,720 --> 00:06:23,400 There is a celebrated story 196 00:06:23,400 --> 00:06:24,880 in the Western tradition like 197 00:06:24,880 --> 00:06:27,680 this, except that not quite 198 00:06:27,680 --> 00:06:29,880 everything was there for us. 199 00:06:29,880 --> 00:06:32,120 There was one particular tree 200 00:06:32,120 --> 00:06:33,240 of which we were not to 201 00:06:33,240 --> 00:06:36,720 partake, a tree of knowledge. 202 00:06:36,720 --> 00:06:38,720 Knowledge and understanding and 203 00:06:38,720 --> 00:06:40,880 wisdom were forbidden to us 204 00:06:40,880 --> 00:06:42,240 in this story. 205 00:06:42,240 --> 00:06:44,880 We were to be kept ignorant. 206 00:06:44,880 --> 00:06:46,840 But we couldn't help ourselves. 207 00:06:46,840 --> 00:06:48,000 We were starving for 208 00:06:48,000 --> 00:06:50,080 knowledge, created hungry, you 209 00:06:50,080 --> 00:06:51,640 might say. 210 00:06:51,640 --> 00:06:52,760 This was the origin of all 211 00:06:52,760 --> 00:06:54,280 our troubles. 212 00:06:54,280 --> 00:06:56,560 In particular, it's why we no 213 00:06:56,560 --> 00:06:58,440 longer live in a garden. 214 00:06:58,440 --> 00:06:59,520 We found out too much. 215 00:07:00,760 --> 00:07:02,760 So long as we were incurious 216 00:07:02,760 --> 00:07:05,480 and obedient, I imagine, we 217 00:07:05,480 --> 00:07:07,040 could console ourselves with 218 00:07:07,040 --> 00:07:09,600 our importance and centrality, 219 00:07:09,600 --> 00:07:10,960 and tell ourselves that we 220 00:07:10,960 --> 00:07:13,960 were the reason the universe was made. 221 00:07:13,960 --> 00:07:15,280 As we began to indulge our 222 00:07:15,280 --> 00:07:18,160 curiosity, though, to explore, 223 00:07:18,160 --> 00:07:19,680 to learn how the universe really 224 00:07:19,680 --> 00:07:23,200 is, we expelled ourselves from Eden. 225 00:07:23,200 --> 00:07:25,280 Angels with a flaming sword 226 00:07:25,280 --> 00:07:27,000 were set as sentries at the 227 00:07:27,000 --> 00:07:31,800 gates of paradise to bar our return. 228 00:07:31,800 --> 00:07:34,920 The gardeners became exiles 229 00:07:34,920 --> 00:07:37,160 and wanderers. 230 00:07:37,160 --> 00:07:39,320 Occasionally we mourn that 231 00:07:39,320 --> 00:07:41,280 lost world, but that, it 232 00:07:41,280 --> 00:07:43,000 seems to me, is maudlin 233 00:07:43,000 --> 00:07:44,640 and sentimental. 234 00:07:44,640 --> 00:07:46,000 We could not happily have 235 00:07:46,000 --> 00:07:47,740 remained ignorant forever. 236 00:07:47,740 --> 00:07:48,960 However, there is in this 237 00:07:48,960 --> 00:07:50,200 universe much of what seems 238 00:07:50,200 --> 00:07:53,560 to be design, but instead we repeatedly 239 00:07:53,560 --> 00:07:54,640 discover that natural 240 00:07:54,640 --> 00:07:57,080 processes, collisional selection 241 00:07:57,080 --> 00:07:59,880 of worlds, say, or natural selection 242 00:07:59,880 --> 00:08:01,640 of gene pools, or even the 243 00:08:01,640 --> 00:08:02,880 convection pattern in a pot 244 00:08:02,880 --> 00:08:06,000 of boiling water, can extract order 245 00:08:06,000 --> 00:08:08,320 out of chaos and deceive us 246 00:08:08,320 --> 00:08:10,400 into deducing purpose where 247 00:08:10,400 --> 00:08:13,280 there is none. 248 00:08:13,280 --> 00:08:15,200 The significance of our lives 249 00:08:15,200 --> 00:08:17,320 and our fragile planet is 250 00:08:17,320 --> 00:08:19,000 then determined only by our own 251 00:08:19,000 --> 00:08:21,120 wisdom and courage. 252 00:08:21,120 --> 00:08:23,000 We are the custodians of 253 00:08:23,000 --> 00:08:24,600 life's meaning. 254 00:08:24,600 --> 00:08:26,760 We long for a parent to care 255 00:08:26,760 --> 00:08:28,600 for us, to forgive us our 256 00:08:28,600 --> 00:08:30,880 errors, to save us from our 257 00:08:30,880 --> 00:08:32,960 childish mistakes. 258 00:08:32,960 --> 00:08:35,040 But knowledge is preferable 259 00:08:35,040 --> 00:08:36,920 to ignorance. 260 00:08:36,920 --> 00:08:38,920 Better by far to embrace the 261 00:08:38,920 --> 00:08:42,080 hard truth than a reassuring fail. 262 00:08:42,080 --> 00:08:43,520 If we crave some cosmic 263 00:08:43,520 --> 00:08:45,240 purpose, then let us find 264 00:08:45,240 --> 00:08:59,440 ourselves a worthy goal. 265 00:09:18,320 --> 00:09:20,040 Consider again that pale blue 266 00:09:20,040 --> 00:09:23,120 dot we've been talking about. 267 00:09:23,120 --> 00:09:24,920 Imagine that you take a good 268 00:09:24,920 --> 00:09:28,040 long look at it. 269 00:09:28,040 --> 00:09:30,480 Imagine you're staring at the 270 00:09:30,480 --> 00:09:33,480 dot for any length of time, 271 00:09:33,480 --> 00:09:37,000 and then try to convince yourself 272 00:09:37,000 --> 00:09:38,800 that God created the whole 273 00:09:38,800 --> 00:09:41,120 universe for one of the ten 274 00:09:41,120 --> 00:09:42,560 million or so species of 275 00:09:42,560 --> 00:09:48,520 life that inhabit that speck of dust. 276 00:09:48,520 --> 00:09:50,920 Now take it a step further. 277 00:09:50,920 --> 00:09:51,520 Imagine that 278 00:09:51,520 --> 00:09:52,760 everything was made just for 279 00:09:52,760 --> 00:09:54,880 a single shade of that 280 00:09:54,880 --> 00:09:58,080 species, or gender, or ethnic 281 00:09:58,080 --> 00:09:59,320 or religious subdivision. 282 00:10:01,160 --> 00:10:02,400 If this doesn't strike you as 283 00:10:02,400 --> 00:10:05,080 unlikely, pick another dot. 284 00:10:05,080 --> 00:10:07,280 it. Imagine it to be inhabited by 285 00:10:07,280 --> 00:10:10,040 a different form of intelligent life. 286 00:10:10,040 --> 00:10:11,360 They, too, cherish 287 00:10:11,360 --> 00:10:12,680 the notion of a God who has 288 00:10:12,680 --> 00:10:15,120 created everything for their benefit. 289 00:10:15,120 --> 00:10:19,040 How seriously do you take their claim? 290 00:10:19,040 --> 00:10:21,840 Our ancestors lived out of doors. 291 00:10:21,840 --> 00:10:23,160 They were as familiar with 292 00:10:23,160 --> 00:10:25,040 the night sky as 293 00:10:25,040 --> 00:10:26,040 most of us are with our 294 00:10:26,040 --> 00:10:28,280 favorite television programs. 295 00:10:28,280 --> 00:10:30,200 The Sun, the Moon, the stars, and 296 00:10:30,200 --> 00:10:32,720 the planets all rose in the 297 00:10:32,720 --> 00:10:35,960 east and set in the west, 298 00:10:35,960 --> 00:10:37,480 traversing the sky overhead in 299 00:10:37,480 --> 00:10:39,240 the interim. 300 00:10:39,240 --> 00:10:40,320 The motion of the heavenly 301 00:10:40,320 --> 00:10:43,400 bodies was not merely a diversion. 302 00:10:43,400 --> 00:10:45,600 For hunters and gatherers, as 303 00:10:45,600 --> 00:10:46,720 well as for agricultural 304 00:10:46,720 --> 00:10:49,200 peoples, knowing about the sky 305 00:10:49,200 --> 00:10:49,800 was a matter 306 00:10:49,800 --> 00:10:52,560 of life and death. 307 00:10:52,560 --> 00:10:53,920 How lucky for us that the 308 00:10:53,920 --> 00:10:55,080 Sun, the Moon, the planets, 309 00:10:55,080 --> 00:10:57,240 and the stars are part of 310 00:10:57,240 --> 00:10:58,560 some elegantly 311 00:10:58,560 --> 00:11:01,120 configured cosmic clockwork. 312 00:11:01,120 --> 00:11:03,040 It seemed to be no accident. 313 00:11:03,040 --> 00:11:04,680 They were put here for a purpose, 314 00:11:04,680 --> 00:11:05,960 for our benefit. 315 00:11:05,960 --> 00:11:07,560 Who else makes use of them? 316 00:11:07,560 --> 00:11:09,480 What else are they good for? 317 00:11:09,480 --> 00:11:10,120 And if the lights 318 00:11:10,120 --> 00:11:11,520 in the sky rise and set 319 00:11:11,520 --> 00:11:13,560 around us, isn't it evident 320 00:11:13,560 --> 00:11:15,440 that we're at the center of 321 00:11:15,440 --> 00:11:17,240 the universe? 322 00:11:17,240 --> 00:11:19,280 These celestial bodies, so 323 00:11:19,280 --> 00:11:21,880 clearly suffused with unEarthly 324 00:11:21,880 --> 00:11:24,520 powers, especially the Sun, 325 00:11:24,520 --> 00:11:26,000 on which we depend for light 326 00:11:26,000 --> 00:11:29,320 and heat circle us like 327 00:11:29,320 --> 00:11:33,840 courtiers fawning on a king. 328 00:11:33,840 --> 00:11:35,080 Even if we had not already 329 00:11:35,080 --> 00:11:37,400 guessed, the most elementary 330 00:11:37,400 --> 00:11:38,240 examination of the 331 00:11:38,240 --> 00:11:42,160 heavens reveals that we are special. 332 00:11:42,160 --> 00:11:43,640 The universe seems designed 333 00:11:43,640 --> 00:11:45,840 for human beings. 334 00:11:45,840 --> 00:11:47,320 It's difficult to contemplate 335 00:11:47,320 --> 00:11:49,520 these circumstances without 336 00:11:49,520 --> 00:11:50,400 experiencing 337 00:11:50,400 --> 00:11:53,720 stirrings of pride and reassurance. 338 00:11:53,720 --> 00:11:56,680 The entire universe made for us. 339 00:11:56,680 --> 00:11:58,920 We must really be something. 340 00:11:58,920 --> 00:12:00,800 This satisfying demonstration 341 00:12:00,800 --> 00:12:03,520 of our importance, buttressed 342 00:12:03,520 --> 00:12:06,520 by daily observations of the heavens, 343 00:12:06,520 --> 00:12:10,080 made the geocentrist conceit a 344 00:12:10,080 --> 00:12:13,360 transcultural truth, taught in 345 00:12:13,360 --> 00:12:15,200 the schools, built into 346 00:12:15,200 --> 00:12:17,480 the language, part and parcel 347 00:12:17,480 --> 00:12:18,920 of great literature and 348 00:12:18,920 --> 00:12:21,160 sacred scripture. 349 00:12:21,160 --> 00:12:23,440 Dissenters were discouraged, 350 00:12:23,440 --> 00:12:26,280 sometimes with torture and death. 351 00:12:26,280 --> 00:12:27,400 It is no wonder that for the 352 00:12:27,400 --> 00:12:29,360 vast bulk of human history no 353 00:12:29,360 --> 00:12:30,880 one questioned it. 354 00:12:30,880 --> 00:12:33,400 Aristotle, Plato, St. Augustine, St. 355 00:12:33,400 --> 00:12:34,880 Thomas Aquinas, 356 00:12:34,880 --> 00:12:36,400 and almost all the great philosophers 357 00:12:36,400 --> 00:12:38,240 and scientists of all cultures 358 00:12:38,240 --> 00:12:39,440 over the three thousand years 359 00:12:39,440 --> 00:12:41,480 ending in the seventeenth century 360 00:12:41,480 --> 00:12:43,360 bought into this delusion. 361 00:12:43,360 --> 00:12:44,200 in. 362 00:12:44,200 --> 00:12:46,000 Some busied themselves figuring 363 00:12:46,000 --> 00:12:47,120 out how the Sun, the Moon, 364 00:12:47,120 --> 00:12:48,600 the stars, and the planets 365 00:12:48,600 --> 00:12:51,240 could be cunningly attached to 366 00:12:51,240 --> 00:12:52,720 perfectly transparent, 367 00:12:52,720 --> 00:12:54,680 crystalline spheres that would 368 00:12:54,680 --> 00:12:55,360 explain the 369 00:12:55,360 --> 00:12:56,560 complex motions of the 370 00:12:56,560 --> 00:12:58,320 celestial bodies so 371 00:12:58,320 --> 00:13:00,640 meticulously chronicled by 372 00:13:00,640 --> 00:13:03,080 generations of astronomers. 373 00:13:03,080 --> 00:13:04,960 Never mind how many kings, 374 00:13:04,960 --> 00:13:07,040 popes, philosophers, scientists, 375 00:13:07,040 --> 00:13:09,960 and poets insisted on the contrary. 376 00:13:09,960 --> 00:13:11,280 The Earth, through those 377 00:13:11,280 --> 00:13:13,360 millennia, stubbornly persisted 378 00:13:13,360 --> 00:13:15,560 in orbiting the Sun. 379 00:13:15,560 --> 00:13:16,480 You might imagine an 380 00:13:16,480 --> 00:13:18,040 uncharitable extraterrestrial 381 00:13:18,040 --> 00:13:19,480 observer looking down on our 382 00:13:19,480 --> 00:13:20,160 species over 383 00:13:20,160 --> 00:13:22,040 all that time, with us 384 00:13:22,040 --> 00:13:23,600 excitedly chattering, the 385 00:13:23,600 --> 00:13:25,280 universe created for us, we're at the 386 00:13:25,280 --> 00:13:26,760 center, everything pays homage 387 00:13:26,760 --> 00:13:29,920 to us, and concluding that 388 00:13:29,920 --> 00:13:32,560 our pretensions are amusing, 389 00:13:32,560 --> 00:13:35,560 our aspirations pathetic, that 390 00:13:35,560 --> 00:13:40,200 this must be the planet of the idiots. 391 00:13:40,200 --> 00:13:40,600 But such a 392 00:13:40,600 --> 00:13:42,320 judgment is too harsh. 393 00:13:42,320 --> 00:13:44,400 We did the best we could. 394 00:13:44,400 --> 00:13:46,040 There was an unlucky coincidence 395 00:13:46,040 --> 00:13:47,320 between everyday appearances 396 00:13:47,320 --> 00:13:51,480 and our secret hopes. We tend not to be 397 00:13:51,480 --> 00:13:53,240 especially critical when 398 00:13:53,240 --> 00:13:54,440 presented with evidence that 399 00:13:54,440 --> 00:13:57,040 seems to confirm our prejudices. 400 00:13:57,040 --> 00:13:58,120 Philosophy and religion 401 00:13:58,120 --> 00:13:59,800 cautioned that the gods, or 402 00:13:59,800 --> 00:14:01,360 God, were far 403 00:14:01,360 --> 00:14:03,880 more powerful than we, jealous 404 00:14:03,880 --> 00:14:05,880 of their prerogatives, and 405 00:14:05,880 --> 00:14:07,840 quick to mete out justice for 406 00:14:07,840 --> 00:14:10,320 insufferable arrogance. 407 00:14:10,320 --> 00:14:12,160 At the same time, these 408 00:14:12,160 --> 00:14:13,440 disciplines had not a clue 409 00:14:13,440 --> 00:14:14,840 that their own teaching of 410 00:14:14,840 --> 00:14:16,400 how the universe is ordered 411 00:14:16,400 --> 00:14:20,280 was a conceit and a delusion. 412 00:14:20,280 --> 00:14:22,040 Every other proposal, and 413 00:14:22,040 --> 00:14:24,240 their number is legion, to 414 00:14:24,240 --> 00:14:26,040 displace us from cosmic center 415 00:14:26,040 --> 00:14:28,800 stage has also been resisted, 416 00:14:28,800 --> 00:14:31,520 in part for similar reasons. 417 00:14:31,520 --> 00:14:35,040 We seem to crave privilege, 418 00:14:35,040 --> 00:14:38,160 merited not by our works but 419 00:14:38,160 --> 00:14:40,720 by our birth, by the mere fact 420 00:14:40,720 --> 00:14:42,880 that, say, we are humans and 421 00:14:42,880 --> 00:14:44,760 born on Earth. 422 00:14:44,760 --> 00:14:45,640 We might call it the 423 00:14:45,640 --> 00:14:47,240 anthropocentric, the 424 00:14:47,240 --> 00:14:51,240 human-centered conceit. 425 00:14:51,240 --> 00:14:52,560 This conceit is brought close 426 00:14:52,560 --> 00:14:54,080 to culmination in the notion 427 00:14:54,080 --> 00:14:57,040 that we are created in God's image. 428 00:14:57,040 --> 00:15:00,000 The creator and ruler of the 429 00:15:00,000 --> 00:15:04,360 entire universe looks just like me. 430 00:15:04,360 --> 00:15:06,600 My, what a coincidence! 431 00:15:06,600 --> 00:15:10,440 How convenient and satisfying! 432 00:15:10,440 --> 00:15:12,000 The 6th century B.C. 433 00:15:12,000 --> 00:15:15,120 Greek philosopher Xenophanes 434 00:15:15,120 --> 00:15:15,600 understood 435 00:15:15,600 --> 00:15:17,000 the arrogance of this perspective. 436 00:15:17,000 --> 00:15:18,880 Here's what he said. 437 00:15:18,880 --> 00:15:20,640 The Ethiopians make their gods 438 00:15:20,640 --> 00:15:23,000 black and snub-nosed. 439 00:15:23,000 --> 00:15:24,680 The Thracians say theirs have 440 00:15:24,680 --> 00:15:27,280 blue eyes and red hair. 441 00:15:27,280 --> 00:15:29,080 Yes, and if oxen 442 00:15:29,080 --> 00:15:31,280 and horses or lions had 443 00:15:31,280 --> 00:15:32,920 hands, and could paint with 444 00:15:32,920 --> 00:15:35,280 their hands, and produce works of art 445 00:15:35,280 --> 00:15:37,320 as men do, horses would paint 446 00:15:37,320 --> 00:15:38,600 the forms of the gods like 447 00:15:38,600 --> 00:15:42,840 horses, and oxen like oxen. 448 00:15:42,840 --> 00:15:44,320 The immense distances to the 449 00:15:44,320 --> 00:15:46,200 stars and the galaxies mean 450 00:15:46,200 --> 00:15:47,680 that we see everything in space 451 00:15:47,680 --> 00:15:49,480 in the past. 452 00:15:49,480 --> 00:15:51,520 Some, as they were before the 453 00:15:51,520 --> 00:15:54,080 Earth came to be, telescopes 454 00:15:54,080 --> 00:15:56,600 are time machines. 455 00:15:56,600 --> 00:15:58,680 Long ago, when an early 456 00:15:58,680 --> 00:16:00,480 galaxy began to pour light 457 00:16:00,480 --> 00:16:03,720 out into the surrounding darkness, no 458 00:16:03,720 --> 00:16:05,960 witness could have known that 459 00:16:05,960 --> 00:16:08,320 billions of years later some 460 00:16:08,320 --> 00:16:10,080 remote clumps of rock and 461 00:16:10,080 --> 00:16:11,920 metal, ice and organic 462 00:16:11,920 --> 00:16:14,240 molecules, would fall together 463 00:16:14,240 --> 00:16:16,480 to make a place called Earth, or 464 00:16:16,480 --> 00:16:18,440 that life would arise and 465 00:16:18,440 --> 00:16:20,480 thinking beings evolve, who 466 00:16:20,480 --> 00:16:21,880 would one day capture a little 467 00:16:21,880 --> 00:16:23,760 of that galactic light and 468 00:16:23,760 --> 00:16:25,800 try to puzzle out what had 469 00:16:25,800 --> 00:16:28,640 sent it on its way. 470 00:16:28,640 --> 00:16:30,600 And after the Earth dies some 471 00:16:30,600 --> 00:16:32,840 five million years from now, 472 00:16:32,840 --> 00:16:34,600 after it is burned to a crisp 473 00:16:34,600 --> 00:16:37,760 or even swallowed by the Sun, 474 00:16:37,760 --> 00:16:39,640 there will be other worlds 475 00:16:39,640 --> 00:16:41,680 and stars and galaxies coming 476 00:16:41,680 --> 00:16:43,800 into being, and they will 477 00:16:43,800 --> 00:16:46,240 know nothing of a place once 478 00:16:46,240 --> 00:16:57,240 called Earth. 479 00:16:57,240 --> 00:17:00,520 Those worlds in space are as 480 00:17:00,520 --> 00:17:02,240 countless as all the grains 481 00:17:02,240 --> 00:17:04,080 of sand on all the beaches 482 00:17:04,080 --> 00:17:05,720 of the Earth. 483 00:17:05,720 --> 00:17:07,200 Each of those worlds is as 484 00:17:07,200 --> 00:17:08,840 real as ours. 485 00:17:08,840 --> 00:17:10,000 In every one of them there's 486 00:17:10,000 --> 00:17:12,320 a succession of incidents, 487 00:17:12,320 --> 00:17:14,400 events, occurrences, which 488 00:17:14,400 --> 00:17:16,440 influence its future. 489 00:17:16,440 --> 00:17:19,240 Countless worlds, numberless 490 00:17:19,240 --> 00:17:22,040 moments, an immensity of space 491 00:17:22,040 --> 00:17:23,840 and time. 492 00:17:23,840 --> 00:17:25,880 And our small planet, at this 493 00:17:25,880 --> 00:17:28,920 moment, here we face a 494 00:17:28,920 --> 00:17:31,520 critical branch point in history. 495 00:17:31,520 --> 00:17:33,680 What we do with our world, 496 00:17:33,680 --> 00:17:35,840 right now, will propagate down 497 00:17:35,840 --> 00:17:37,160 through the centuries and 498 00:17:37,160 --> 00:17:38,680 powerfully affect the destiny 499 00:17:38,680 --> 00:17:40,720 of our descendants. 500 00:17:40,720 --> 00:17:42,600 It is well within our power 501 00:17:42,600 --> 00:17:44,880 to destroy our civilization 502 00:17:44,880 --> 00:17:47,760 and perhaps our species as well. 503 00:17:47,760 --> 00:17:48,840 If we capitulate to 504 00:17:48,840 --> 00:17:52,920 superstition or greed or stupidity, 505 00:17:52,920 --> 00:17:54,320 we can plunge our world into 506 00:17:54,320 --> 00:17:55,680 a darkness deeper than the 507 00:17:55,680 --> 00:17:57,680 time between the collapse of 508 00:17:57,680 --> 00:17:59,080 classical civilization and the 509 00:17:59,080 --> 00:18:01,160 Italian Renaissance. 510 00:18:01,160 --> 00:18:03,040 But we are also capable of 511 00:18:03,040 --> 00:18:05,400 using our compassion and our 512 00:18:05,400 --> 00:18:06,120 intelligence, 513 00:18:06,120 --> 00:18:08,600 our technology and our wealth, 514 00:18:08,600 --> 00:18:11,320 to make an abundant and 515 00:18:11,320 --> 00:18:13,160 meaningful life for every inhabitant 516 00:18:13,160 --> 00:18:15,640 of this planet, to enhance 517 00:18:15,640 --> 00:18:17,600 enormously our understanding of 518 00:18:17,600 --> 00:18:20,400 the universe, and to carry 519 00:18:20,400 --> 00:18:28,760 us to the stars. 520 00:18:37,440 --> 00:18:40,440 We were wanderers from the beginning. 521 00:18:40,440 --> 00:18:41,840 We knew every stand of tree 522 00:18:41,840 --> 00:18:43,680 for a hundred miles. 523 00:18:43,680 --> 00:18:44,960 When the fruits or nuts were 524 00:18:44,960 --> 00:18:46,560 ripe, we were there. 525 00:18:46,560 --> 00:18:48,000 there. We followed the herds 526 00:18:48,000 --> 00:18:50,040 in their annual migrations. 527 00:18:50,040 --> 00:18:53,000 We rejoiced in fresh meat. Through 528 00:18:53,000 --> 00:18:56,320 stealth, feint, ambush, and 529 00:18:56,320 --> 00:18:58,880 main-force assault, a few of 530 00:18:58,880 --> 00:19:01,000 us cooperating accomplished what 531 00:19:01,000 --> 00:19:02,040 many of us, each hunting 532 00:19:02,040 --> 00:19:04,080 alone, could not. 533 00:19:04,080 --> 00:19:06,440 We depended on one another. 534 00:19:06,440 --> 00:19:07,320 Making it on our 535 00:19:07,320 --> 00:19:08,600 own was as ludicrous to 536 00:19:08,600 --> 00:19:11,400 imagine as was settling down. 537 00:19:11,400 --> 00:19:14,840 For 99.9 percent of the time since our 538 00:19:14,840 --> 00:19:16,760 species came to be, we were 539 00:19:16,760 --> 00:19:20,200 hunters and foragers, wanderers 540 00:19:20,200 --> 00:19:22,960 on the savannas and the steppes. 541 00:19:22,960 --> 00:19:26,000 The frontier was everywhere. 542 00:19:26,000 --> 00:19:27,960 We were bounded only by the 543 00:19:27,960 --> 00:19:31,720 Earth and the ocean and the sky. 544 00:19:31,720 --> 00:19:33,760 In the last 10,000 years, an 545 00:19:33,760 --> 00:19:36,160 instant in our long history, 546 00:19:36,160 --> 00:19:38,920 we've abandoned the nomadic life. 547 00:19:38,920 --> 00:19:40,200 For all its material 548 00:19:40,200 --> 00:19:42,520 advantages, the sedentary life 549 00:19:42,520 --> 00:19:46,960 has left us edgy, unfulfilled. 550 00:19:46,960 --> 00:19:49,200 The open road still softly 551 00:19:49,200 --> 00:19:51,600 calls, like a nearly forgotten 552 00:19:51,600 --> 00:19:53,600 song of childhood. 553 00:19:53,600 --> 00:19:55,240 We invest far off places with 554 00:19:55,240 --> 00:19:58,040 a certain romance. 555 00:19:58,040 --> 00:19:59,920 The appeal, I suspect, has 556 00:19:59,920 --> 00:20:02,240 been meticulously crafted by 557 00:20:02,240 --> 00:20:04,240 natural selection as an essential 558 00:20:04,240 --> 00:20:05,680 element in our survival. 559 00:20:05,680 --> 00:20:10,080 all. Long summers, mild winters, 560 00:20:10,080 --> 00:20:12,240 rich harvests, plentiful 561 00:20:12,240 --> 00:20:16,040 game—none of them lasts forever. 562 00:20:16,040 --> 00:20:17,600 It is beyond our powers to 563 00:20:17,600 --> 00:20:19,560 predict the future. 564 00:20:19,560 --> 00:20:21,080 Catastrophic events have a way 565 00:20:21,080 --> 00:20:22,320 of sneaking 566 00:20:22,320 --> 00:20:25,760 up on us, of catching us unaware. 567 00:20:25,760 --> 00:20:27,440 Your own life, or your 568 00:20:27,440 --> 00:20:29,560 band's, or even your species' 569 00:20:29,560 --> 00:20:31,080 These might be owed to a 570 00:20:31,080 --> 00:20:33,760 restless few, drawn by a 571 00:20:33,760 --> 00:20:36,120 craving they can hardly articulate or 572 00:20:36,120 --> 00:20:38,160 understand to undiscovered 573 00:20:38,160 --> 00:20:41,480 lands and new worlds. 574 00:20:41,480 --> 00:20:42,560 To the ancient Greeks and 575 00:20:42,560 --> 00:20:44,360 Romans, the known world 576 00:20:44,360 --> 00:20:48,240 comprised Europe and an attenuated Asia 577 00:20:48,240 --> 00:20:50,200 and Africa, all surrounded by 578 00:20:50,200 --> 00:20:53,340 an impassable world ocean. 579 00:20:53,340 --> 00:20:54,200 them. 580 00:20:54,200 --> 00:20:55,680 Travelers might encounter 581 00:20:55,680 --> 00:20:57,600 inferior beings called 582 00:20:57,600 --> 00:21:01,480 barbarians or superior beings called 583 00:21:01,480 --> 00:21:03,800 gods, but there were not very 584 00:21:03,800 --> 00:21:05,680 many gods, at least at first, 585 00:21:05,680 --> 00:21:08,480 perhaps only a few dozen. 586 00:21:08,480 --> 00:21:10,440 They lived on mountains, under 587 00:21:10,440 --> 00:21:13,200 the Earth, in the sea, or up 588 00:21:13,200 --> 00:21:14,920 there in the sky. 589 00:21:14,920 --> 00:21:16,720 They sent messages to people, 590 00:21:16,720 --> 00:21:18,640 intervened in human affairs, 591 00:21:18,640 --> 00:21:21,680 and interbred with us. 592 00:21:21,680 --> 00:21:24,000 As time passed, as the human 593 00:21:24,000 --> 00:21:25,640 exploratory capacity hit its 594 00:21:25,640 --> 00:21:28,760 stride, there were surprises. 595 00:21:28,760 --> 00:21:30,400 Barbarians could be fully as 596 00:21:30,400 --> 00:21:33,160 clever as Greeks and Romans. 597 00:21:33,160 --> 00:21:35,160 Africa and Asia were larger 598 00:21:35,160 --> 00:21:37,360 than anyone had guessed. 599 00:21:37,360 --> 00:21:40,440 The world ocean was not impassable. 600 00:21:40,440 --> 00:21:42,880 Three new continents existed, 601 00:21:42,880 --> 00:21:44,960 had been settled by Asians in 602 00:21:44,960 --> 00:21:47,000 ages past, and the news had 603 00:21:47,000 --> 00:21:48,320 never reached Europe. 604 00:21:48,320 --> 00:21:51,480 ship. Also, the gods were 605 00:21:51,480 --> 00:21:53,960 disappointingly hard to find. 606 00:21:53,960 --> 00:21:55,280 Since we first emerged a few 607 00:21:55,280 --> 00:21:56,520 million years ago in East 608 00:21:56,520 --> 00:21:59,120 Africa, we've meandered our 609 00:21:59,120 --> 00:22:01,520 way around the planet. There are now 610 00:22:01,520 --> 00:22:03,480 people on every continent and 611 00:22:03,480 --> 00:22:05,640 the remotest islands, from 612 00:22:05,640 --> 00:22:08,160 pole to pole, from Mount Everest 613 00:22:08,160 --> 00:22:09,840 to the Dead Sea, on the 614 00:22:09,840 --> 00:22:12,440 ocean bottoms, and even, 615 00:22:12,440 --> 00:22:14,880 occasionally, in residence 200 616 00:22:14,880 --> 00:22:16,280 miles up. 617 00:22:16,280 --> 00:22:19,280 Humans, like the gods of old, 618 00:22:19,280 --> 00:22:21,040 living in the sky. 619 00:22:21,040 --> 00:22:23,360 These days, there seems to be nowhere 620 00:22:23,360 --> 00:22:25,160 left to explore. 621 00:22:25,160 --> 00:22:27,840 Victims of their very success, 622 00:22:27,840 --> 00:22:30,960 the explorers now pretty much 623 00:22:30,960 --> 00:22:32,840 stay home. 624 00:22:32,840 --> 00:22:35,080 Vast migrations of people, 625 00:22:35,080 --> 00:22:38,040 some voluntary, most not, have 626 00:22:38,040 --> 00:22:40,280 shaped the human condition. 627 00:22:40,280 --> 00:22:42,240 More of us flee from war, 628 00:22:42,240 --> 00:22:44,800 oppression and famine today 629 00:22:44,800 --> 00:22:45,960 than at any other time in 630 00:22:45,960 --> 00:22:47,760 human history. 631 00:22:47,760 --> 00:22:49,440 As the Earth's climate changes 632 00:22:49,440 --> 00:22:51,240 in the coming decades, there 633 00:22:51,240 --> 00:22:52,680 are likely to be far greater 634 00:22:52,680 --> 00:22:55,800 numbers of environmental refugees. 635 00:22:55,800 --> 00:22:58,440 Better places will always call to us. 636 00:22:59,200 --> 00:23:00,800 Tides of people will continue 637 00:23:00,800 --> 00:23:04,040 to ebb and flow across the planet. 638 00:23:04,040 --> 00:23:06,160 But the lands we run to now 639 00:23:06,160 --> 00:23:07,540 have already been settled. 640 00:23:07,540 --> 00:23:10,120 world. Other people, often 641 00:23:10,120 --> 00:23:12,240 unsympathetic to our plight, 642 00:23:12,240 --> 00:23:15,680 are there before us. Maybe it's 643 00:23:15,680 --> 00:23:17,640 a little early, maybe the 644 00:23:17,640 --> 00:23:20,200 time is not quite yet, but 645 00:23:20,200 --> 00:23:22,560 those are the worlds promising 646 00:23:22,560 --> 00:23:26,080 untold opportunities beckon. 647 00:23:26,080 --> 00:23:27,360 In the last few decades, the 648 00:23:27,360 --> 00:23:28,000 United States 649 00:23:28,000 --> 00:23:29,600 and the former Soviet Union 650 00:23:29,600 --> 00:23:31,000 have accomplished something 651 00:23:31,000 --> 00:23:34,120 stunning and historic. The close-up 652 00:23:34,120 --> 00:23:36,080 examination of all those 653 00:23:36,080 --> 00:23:38,280 points of light from Mercury 654 00:23:38,280 --> 00:23:40,920 to Saturn that moved our ancestors 655 00:23:40,920 --> 00:23:44,480 to wonder and to science. 656 00:23:44,480 --> 00:23:45,800 Since the advent of successful 657 00:23:45,800 --> 00:23:48,480 interplanetary flight in 1962, 658 00:23:48,480 --> 00:23:50,840 our machines have flown by 659 00:23:50,840 --> 00:23:54,040 or orbited or landed on more 660 00:23:54,040 --> 00:23:56,880 than seventy new worlds. 661 00:23:56,880 --> 00:24:00,720 We have wandered among the wanderers. 662 00:24:00,720 --> 00:24:02,600 We have found vast volcanic 663 00:24:02,600 --> 00:24:04,400 eminences that dwarf the 664 00:24:04,400 --> 00:24:07,080 highest mountain on Earth, ancient 665 00:24:07,080 --> 00:24:09,400 river valleys on two planets, 666 00:24:09,400 --> 00:24:11,760 enigmatically one too cold and 667 00:24:11,760 --> 00:24:13,080 the other too hot for running 668 00:24:13,080 --> 00:24:15,800 water, a giant planet with an 669 00:24:15,800 --> 00:24:18,080 interior of liquid metallic 670 00:24:18,080 --> 00:24:20,360 hydrogen into which a thousand 671 00:24:20,360 --> 00:24:22,720 Earths would fit, whole moons 672 00:24:22,720 --> 00:24:24,760 that have melted, a 673 00:24:24,760 --> 00:24:26,160 cloud-covered place with an 674 00:24:26,160 --> 00:24:26,840 atmosphere of 675 00:24:26,840 --> 00:24:29,080 Corrosive acids, where even 676 00:24:29,080 --> 00:24:31,080 the high plateaus are above 677 00:24:31,080 --> 00:24:33,640 the melting point of lead. 678 00:24:33,640 --> 00:24:35,880 Ancient surfaces, on which a 679 00:24:35,880 --> 00:24:37,520 faithful record of the violent 680 00:24:37,520 --> 00:24:38,920 formation of the solar system 681 00:24:38,920 --> 00:24:40,920 is engraved. 682 00:24:40,920 --> 00:24:42,560 Refugee ice worlds from the 683 00:24:42,560 --> 00:24:45,680 trans-Plutonian depths. 684 00:24:45,680 --> 00:24:47,160 Exquisitely patterned ring 685 00:24:47,160 --> 00:24:49,440 systems, marking the subtle 686 00:24:49,440 --> 00:24:51,840 harmonies of gravity. 687 00:24:51,840 --> 00:24:53,320 and a world surrounded by 688 00:24:53,320 --> 00:24:55,280 clouds of complex organic 689 00:24:55,280 --> 00:24:57,320 molecules like those that in 690 00:24:57,320 --> 00:24:57,800 the earliest 691 00:24:57,800 --> 00:24:59,440 history of our planet led to 692 00:24:59,440 --> 00:25:01,680 the origin of life. 693 00:25:01,680 --> 00:25:08,320 Silently, they orbit the Sun, waiting. 694 00:25:08,320 --> 00:25:09,680 We have uncovered wonders 695 00:25:09,680 --> 00:25:11,520 undreamt by our ancestors who 696 00:25:11,520 --> 00:25:13,400 first speculated on the nature 697 00:25:13,400 --> 00:25:14,840 of those wandering lights in 698 00:25:14,840 --> 00:25:16,400 the night sky. 699 00:25:16,400 --> 00:25:17,880 We have proved the origins of 700 00:25:17,880 --> 00:25:20,080 our planet and ourselves. 701 00:25:20,080 --> 00:25:21,440 By discovering what else is 702 00:25:21,440 --> 00:25:23,640 possible, by coming face to 703 00:25:23,640 --> 00:25:26,040 face with alternative fates of worlds 704 00:25:26,040 --> 00:25:27,840 more or less like our own, 705 00:25:27,840 --> 00:25:29,320 we have begun to better 706 00:25:29,320 --> 00:25:31,000 understand the Earth. 707 00:25:31,000 --> 00:25:33,200 Every one of those worlds is 708 00:25:33,200 --> 00:25:36,400 lovely and instructive, but so 709 00:25:36,400 --> 00:25:38,720 far as we know, they are also, every 710 00:25:38,720 --> 00:25:42,520 one of them, desolate and barren. 711 00:25:42,520 --> 00:25:47,160 Out there, there are no better places. 712 00:25:47,160 --> 00:25:49,280 So far, at least. 713 00:25:49,280 --> 00:25:50,680 During the Viking robotic 714 00:25:50,680 --> 00:25:52,440 missions, beginning in July 715 00:25:52,440 --> 00:25:56,680 1976, in a certain sense, I spent 716 00:25:56,680 --> 00:25:58,720 a year on Mars. 717 00:25:58,720 --> 00:26:00,160 I examined the boulders and 718 00:26:00,160 --> 00:26:02,840 sand dunes, the sky red even 719 00:26:02,840 --> 00:26:05,280 at high noon, the ancient river 720 00:26:05,280 --> 00:26:07,520 valleys, the soaring volcanic 721 00:26:07,520 --> 00:26:09,200 mountains, the fierce wind 722 00:26:09,200 --> 00:26:11,240 erosion, the laminated 723 00:26:11,240 --> 00:26:13,840 polar terrain, the two dark 724 00:26:13,840 --> 00:26:16,440 potato-shaped moons. 725 00:26:16,440 --> 00:26:18,760 But there was no life. Not a 726 00:26:18,760 --> 00:26:20,600 cricket, or a blade of grass, 727 00:26:20,600 --> 00:26:22,200 or even, so far as we can 728 00:26:22,200 --> 00:26:25,800 tell for sure, a microbe. 729 00:26:25,800 --> 00:26:29,240 Life is a comparative rarity. 730 00:26:29,240 --> 00:26:30,680 You can survey dozens of 731 00:26:30,680 --> 00:26:32,400 worlds and find that 732 00:26:32,400 --> 00:26:34,600 only one of them does life 733 00:26:34,600 --> 00:26:40,080 arise and evolve and persist. 734 00:26:40,080 --> 00:26:43,080 Neptune lies a million times 735 00:26:43,080 --> 00:26:45,160 further from Earth than New 736 00:26:45,160 --> 00:26:48,040 York City is from the banks 737 00:26:48,040 --> 00:26:50,560 of the River Bug. 738 00:26:50,560 --> 00:26:51,640 But there are no distant 739 00:26:51,640 --> 00:26:54,320 relatives, no humans, and 740 00:26:54,320 --> 00:26:55,680 apparently no life waiting for 741 00:26:55,680 --> 00:26:57,760 us on those other worlds. 742 00:26:57,760 --> 00:26:59,600 No letters conveyed by recent 743 00:26:59,600 --> 00:27:01,880 émigrés help us to understand 744 00:27:01,880 --> 00:27:03,360 the new land. 745 00:27:03,360 --> 00:27:05,600 Only digital data, transmitted 746 00:27:05,600 --> 00:27:07,400 at the speed of light by 747 00:27:07,400 --> 00:27:12,800 unfeeling, precise robot emissaries. 748 00:27:12,800 --> 00:27:15,160 They tell us that these new 749 00:27:15,160 --> 00:27:17,360 worlds are not much like home. 750 00:27:17,360 --> 00:27:18,880 But we continue to search 751 00:27:18,880 --> 00:27:20,640 for inhabitants. 752 00:27:20,640 --> 00:27:22,240 We can't help it. 753 00:27:22,240 --> 00:27:25,360 Life looks for life. 754 00:27:25,360 --> 00:27:26,960 No one on Earth, not the 755 00:27:26,960 --> 00:27:28,720 richest among us, can afford 756 00:27:28,720 --> 00:27:30,240 the passage. 757 00:27:30,240 --> 00:27:31,320 So we can't pick up and 758 00:27:31,320 --> 00:27:33,560 leave for Mars or Titan on a whim, 759 00:27:33,560 --> 00:27:36,160 or because we're bored, or 760 00:27:36,160 --> 00:27:37,560 out of work, or drafted into 761 00:27:37,560 --> 00:27:39,880 the army, or oppressed, 762 00:27:39,880 --> 00:27:41,800 or because justly or unjustly 763 00:27:41,800 --> 00:27:44,240 we've been accused of a crime. 764 00:27:44,240 --> 00:27:45,400 There does not seem to be 765 00:27:45,400 --> 00:27:47,440 sufficient short-term profit to 766 00:27:47,440 --> 00:27:49,800 motivate private industry. 767 00:27:49,800 --> 00:27:50,960 If we humans ever go to 768 00:27:50,960 --> 00:27:53,800 those worlds, then it will be 769 00:27:53,800 --> 00:27:56,480 because a nation or a consortium 770 00:27:56,480 --> 00:27:58,280 of them believes it to be to 771 00:27:58,280 --> 00:28:00,160 its advantage, or to the 772 00:28:00,160 --> 00:28:02,400 advantage of the human species. 773 00:28:02,400 --> 00:28:04,520 Just now, there are a great 774 00:28:04,520 --> 00:28:06,400 many matters that are pressing 775 00:28:06,400 --> 00:28:08,640 in on us, that compete for the 776 00:28:08,640 --> 00:28:10,440 money it takes to send people 777 00:28:10,440 --> 00:28:12,280 to other worlds. 778 00:28:12,280 --> 00:28:13,760 Should we solve those problems 779 00:28:13,760 --> 00:28:18,920 first, or are they a reason for going? 780 00:28:18,920 --> 00:28:20,160 Even if the call of the open 781 00:28:20,160 --> 00:28:22,960 road is muted in our time, a 782 00:28:22,960 --> 00:28:24,360 central element of the human 783 00:28:24,360 --> 00:28:28,120 future lies far beyond the Earth. 784 00:28:36,080 --> 00:28:38,680 It's a sultry night in July. 785 00:28:38,680 --> 00:28:41,600 You've fallen asleep in the armchair. 786 00:28:41,600 --> 00:28:43,600 Abruptly, you startle 787 00:28:43,600 --> 00:28:46,000 awake disoriented. 788 00:28:46,000 --> 00:28:48,560 The television set is on, but 789 00:28:48,560 --> 00:28:50,680 not the sound. 790 00:28:50,680 --> 00:28:52,120 You strain to understand what 791 00:28:52,120 --> 00:28:53,400 you are seeing. 792 00:28:53,400 --> 00:28:55,800 Two ghostly white figures in 793 00:28:55,800 --> 00:28:58,200 coveralls and helmets are 794 00:28:58,200 --> 00:29:02,680 softly dancing under a pitch-black sky. 795 00:29:02,680 --> 00:29:04,080 They make strange little 796 00:29:04,080 --> 00:29:06,600 skipping motions, which propel 797 00:29:06,600 --> 00:29:08,640 them upward amid barely perceptible 798 00:29:08,640 --> 00:29:10,960 clouds of dust. 799 00:29:10,960 --> 00:29:13,320 But something is wrong. 800 00:29:13,320 --> 00:29:16,440 They take too long to come down. 801 00:29:16,440 --> 00:29:18,640 Encumbered as they are, they 802 00:29:18,640 --> 00:29:22,160 seem to be flying—a little. 803 00:29:22,160 --> 00:29:24,640 You rub your eyes, but the 804 00:29:24,640 --> 00:29:28,040 dreamlike tableau persists. 805 00:29:28,920 --> 00:29:30,480 Of all the events surrounding 806 00:29:30,480 --> 00:29:31,840 Apollo 11's landing on the 807 00:29:31,840 --> 00:29:35,760 Moon on July 20, 1969, my 808 00:29:35,760 --> 00:29:37,840 most vivid recollection is its 809 00:29:37,840 --> 00:29:40,200 unreal quality. 810 00:29:40,200 --> 00:29:43,400 Neil Armstrong and Buzz Aldrin 811 00:29:43,400 --> 00:29:46,040 shuffled along the gray, dusty 812 00:29:46,040 --> 00:29:48,960 lunar surface, the Earth looming 813 00:29:48,960 --> 00:29:51,120 large in their sky, while 814 00:29:51,120 --> 00:29:53,360 Michael Collins, now the 815 00:29:53,360 --> 00:29:57,600 moon's own moon, orbited above them 816 00:29:57,600 --> 00:30:00,400 in lonely vigil. 817 00:30:00,400 --> 00:30:01,720 Yes it was an astonishing 818 00:30:01,720 --> 00:30:03,880 technological achievement and a 819 00:30:03,880 --> 00:30:06,840 triumph for the United States. 820 00:30:06,840 --> 00:30:08,480 Yes, the astronauts displayed 821 00:30:08,480 --> 00:30:10,480 death-defying courage. 822 00:30:10,480 --> 00:30:12,040 Yes, as Armstrong said as he 823 00:30:12,040 --> 00:30:14,120 first alighted, this was a 824 00:30:14,120 --> 00:30:17,720 historic step for the human species. 825 00:30:17,720 --> 00:30:18,840 But if you turned off the 826 00:30:18,840 --> 00:30:20,880 bi-play between mission control 827 00:30:20,880 --> 00:30:22,600 and the Sea of Tranquility 828 00:30:22,600 --> 00:30:23,840 and stared into that 829 00:30:23,840 --> 00:30:24,800 black-and-white television 830 00:30:24,800 --> 00:30:28,000 monitor, you could glimpse 831 00:30:28,000 --> 00:30:28,760 that we humans 832 00:30:28,760 --> 00:30:31,880 had entered the realm of myth 833 00:30:31,880 --> 00:30:34,720 and legend. 834 00:30:34,720 --> 00:30:36,000 We knew the Moon from our 835 00:30:36,000 --> 00:30:37,880 earliest days. 836 00:30:37,880 --> 00:30:38,920 It was there when our 837 00:30:38,920 --> 00:30:40,240 ancestors descended from the 838 00:30:40,240 --> 00:30:42,360 trees into the savannas, 839 00:30:42,360 --> 00:30:44,480 when we learned to walk upright, 840 00:30:44,480 --> 00:30:47,360 when we first devised stone tools, 841 00:30:47,360 --> 00:30:49,480 when we domesticated fire, 842 00:30:49,480 --> 00:30:51,080 when we invented agriculture 843 00:30:51,080 --> 00:30:52,840 and built cities 844 00:30:52,840 --> 00:30:55,960 and set out to subdue the Earth. 845 00:30:55,960 --> 00:30:57,920 Folklore and popular songs 846 00:30:58,800 --> 00:31:02,520 celebrate a mysterious connection 847 00:31:02,520 --> 00:31:05,680 between the Moon and love. 848 00:31:05,680 --> 00:31:08,320 Its waxing and waning from 849 00:31:08,320 --> 00:31:10,400 crescent to full to crescent 850 00:31:10,400 --> 00:31:14,040 to new was widely understood 851 00:31:14,040 --> 00:31:16,760 as a celestial metaphor of 852 00:31:16,760 --> 00:31:20,160 death and rebirth. 853 00:31:20,160 --> 00:31:21,200 Walking on the Moon would 854 00:31:21,200 --> 00:31:23,720 have seemed a screwball idea. 855 00:31:23,720 --> 00:31:24,720 It made more sense to 856 00:31:24,720 --> 00:31:26,160 imagine somehow climbing up 857 00:31:26,160 --> 00:31:28,600 into the sky on a ladder or 858 00:31:28,600 --> 00:31:29,760 on the back of a giant 859 00:31:29,760 --> 00:31:32,480 bird, grabbing the Moon and 860 00:31:32,480 --> 00:31:35,000 bringing it down to Earth. 861 00:31:35,000 --> 00:31:37,200 Nobody ever succeeded, although 862 00:31:37,200 --> 00:31:39,560 there were myths aplenty about 863 00:31:39,560 --> 00:31:42,280 heroes who had tried. 864 00:31:42,280 --> 00:31:43,960 Not until a few centuries ago 865 00:31:43,960 --> 00:31:45,480 did the idea of the Moon as 866 00:31:45,480 --> 00:31:48,160 a place a quarter million miles 867 00:31:48,160 --> 00:31:52,680 away gain wide currency. 868 00:31:52,680 --> 00:31:54,600 And in that brief flicker of 869 00:31:54,600 --> 00:31:56,880 time, we've gone from the 870 00:31:56,880 --> 00:31:58,880 earliest steps in understanding the 871 00:31:58,880 --> 00:32:01,440 nature, to walking and 872 00:32:01,440 --> 00:32:05,040 joyriding on its surface. 873 00:32:05,040 --> 00:32:06,760 We calculated how objects move 874 00:32:06,760 --> 00:32:09,720 in space, liquefied oxygen 875 00:32:09,720 --> 00:32:12,200 from the air, invented big 876 00:32:12,200 --> 00:32:14,760 rockets, telemetry, reliable 877 00:32:14,760 --> 00:32:16,800 electronics, inertial guidance, 878 00:32:16,800 --> 00:32:18,440 and much else. 879 00:32:18,440 --> 00:32:21,480 And then we sailed out into the 880 00:32:24,560 --> 00:32:26,840 In the late Roman Empire, 881 00:32:26,840 --> 00:32:28,800 pagan philosophers had attacked 882 00:32:28,800 --> 00:32:31,320 Christian doctrine on the ascension 883 00:32:31,320 --> 00:32:32,440 to heaven of the body of 884 00:32:32,440 --> 00:32:34,720 Christ and on the promised 885 00:32:34,720 --> 00:32:38,400 bodily resurrection of the dead. 886 00:32:38,400 --> 00:32:41,040 Saint Augustine rejoined in 887 00:32:41,040 --> 00:32:43,960 these words, If human skill 888 00:32:43,960 --> 00:32:46,760 can by some contrivance fabricate 889 00:32:46,760 --> 00:32:49,040 vessels that float out of 890 00:32:49,040 --> 00:32:51,320 metals which sink. 891 00:32:51,320 --> 00:32:53,040 How much more credible is it 892 00:32:53,040 --> 00:32:55,080 that God, by some hidden mode 893 00:32:55,080 --> 00:32:57,200 of operation, should even 894 00:32:57,200 --> 00:32:59,120 more certainly effect that 895 00:32:59,120 --> 00:33:01,080 these Earthly masses be 896 00:33:01,080 --> 00:33:03,800 emancipated from the chains 897 00:33:03,800 --> 00:33:07,120 that bind them to Earth? 898 00:33:07,120 --> 00:33:08,840 That humans should one day 899 00:33:08,840 --> 00:33:10,320 discover such a mode of 900 00:33:10,320 --> 00:33:14,560 operation was beyond imagining. 901 00:33:14,560 --> 00:33:17,080 1,500 years later, we 902 00:33:17,080 --> 00:33:20,720 emancipated ourselves. 903 00:33:20,720 --> 00:33:23,160 Once upon a time, we soared 904 00:33:23,160 --> 00:33:27,200 into the solar system for a few years. 905 00:33:27,200 --> 00:33:29,160 Then we hurried back. 906 00:33:29,160 --> 00:33:30,200 Why? 907 00:33:30,200 --> 00:33:31,800 What happened? 908 00:33:31,800 --> 00:33:35,240 What was Apollo really about? 909 00:33:35,240 --> 00:33:37,320 The scope and audacity of 910 00:33:37,320 --> 00:33:40,600 John Kennedy's May 25, 1961 911 00:33:40,600 --> 00:33:43,960 message to a joint session of Congress 912 00:33:43,960 --> 00:33:47,680 on urgent national needs, it 913 00:33:47,680 --> 00:33:49,680 dazzled me. 914 00:33:49,680 --> 00:33:51,280 We would use rockets not yet 915 00:33:51,280 --> 00:33:54,000 designed, and alloys not yet 916 00:33:54,000 --> 00:33:57,080 conceived, navigation and docking 917 00:33:57,080 --> 00:33:59,680 schemes not yet devised, in 918 00:33:59,680 --> 00:34:01,000 order to send a man to an 919 00:34:01,000 --> 00:34:03,200 unknown world, a world not yet 920 00:34:03,200 --> 00:34:04,320 explored, not even in a 921 00:34:04,320 --> 00:34:07,840 preliminary way, not even by robots. 922 00:34:07,840 --> 00:34:09,120 And we would bring him safely 923 00:34:09,120 --> 00:34:11,240 back, and we would do it 924 00:34:11,240 --> 00:34:14,120 before the decade was over. 925 00:34:14,120 --> 00:34:16,800 This confident pronouncement 926 00:34:16,800 --> 00:34:19,160 was made before any American 927 00:34:19,160 --> 00:34:21,400 had even achieved Earth orbit. 928 00:34:21,400 --> 00:34:23,280 I actually thought that all 929 00:34:23,280 --> 00:34:24,440 this had something centrally 930 00:34:24,440 --> 00:34:26,360 to do with science. 931 00:34:26,360 --> 00:34:29,400 Suddenly, I understood. 932 00:34:29,400 --> 00:34:30,800 Sending people to orbit the 933 00:34:30,800 --> 00:34:33,720 Earth, or robots to orbit the 934 00:34:33,720 --> 00:34:37,440 Sun, requires rockets. 935 00:34:37,440 --> 00:34:41,880 Big, reliable, powerful rockets. 936 00:34:41,880 --> 00:34:43,680 Those same rockets can be 937 00:34:43,680 --> 00:34:45,560 used for nuclear war. 938 00:34:45,560 --> 00:34:47,200 The same technology that 939 00:34:47,200 --> 00:34:50,000 transports a man to the Moon 940 00:34:50,000 --> 00:34:51,480 can carry nuclear warheads 941 00:34:51,480 --> 00:34:54,080 halfway around the world. 942 00:34:54,080 --> 00:34:55,280 The same technology that puts 943 00:34:55,280 --> 00:34:56,520 an astronomer in a telescope 944 00:34:56,520 --> 00:34:57,640 in Earth orbit 945 00:34:57,640 --> 00:35:01,120 It can also put up a laser 946 00:35:01,120 --> 00:35:03,280 battle station. 947 00:35:03,280 --> 00:35:05,400 A case can be made, then, 948 00:35:05,400 --> 00:35:06,800 that Apollo served another 949 00:35:06,800 --> 00:35:10,040 purpose, to move the U.S.-Soviet space 950 00:35:10,040 --> 00:35:13,160 competition from a military to 951 00:35:13,160 --> 00:35:15,280 a civilian arena. 952 00:35:15,280 --> 00:35:18,080 Apollo was not mainly about science. 953 00:35:18,080 --> 00:35:21,120 It was not even mainly about space. 954 00:35:21,120 --> 00:35:23,680 Apollo was about ideological 955 00:35:23,680 --> 00:35:27,720 confrontation and nuclear war, but more 956 00:35:27,720 --> 00:35:30,120 important than any of this, 957 00:35:30,120 --> 00:35:34,280 Apollo provided an aegis, an 958 00:35:34,280 --> 00:35:36,360 umbrella, under 959 00:35:36,360 --> 00:35:38,240 which brilliantly engineered 960 00:35:38,240 --> 00:35:40,440 robot spacecraft were 961 00:35:40,440 --> 00:35:41,440 dispatched throughout 962 00:35:41,440 --> 00:35:44,720 the solar system, making that 963 00:35:44,720 --> 00:35:46,920 preliminary reconnaissance of 964 00:35:46,920 --> 00:35:49,480 dozens of worlds. The 965 00:35:49,480 --> 00:35:52,560 Offspring of Apollo have now 966 00:35:52,560 --> 00:35:56,320 reached the planetary frontiers. 967 00:35:56,320 --> 00:36:00,600 Apollo conveyed a confidence, 968 00:36:00,600 --> 00:36:04,200 energy, and breadth of vision 969 00:36:04,200 --> 00:36:06,160 that did capture the 970 00:36:06,160 --> 00:36:07,960 imagination of the world. 971 00:36:07,960 --> 00:36:11,560 That, too, was part of its purpose. 972 00:36:11,560 --> 00:36:14,600 It inspired an optimism about 973 00:36:14,600 --> 00:36:16,360 technology, 974 00:36:16,360 --> 00:36:20,680 and enthusiasm for the future. 975 00:36:20,680 --> 00:36:22,080 The Apollo astronauts on their 976 00:36:22,080 --> 00:36:25,280 way to and from the Moon 977 00:36:25,280 --> 00:36:27,560 photographed their home planet. 978 00:36:28,800 --> 00:36:31,720 It was a natural thing to do, 979 00:36:31,720 --> 00:36:33,280 but it had consequences that 980 00:36:33,280 --> 00:36:35,800 few foresaw. 981 00:36:35,800 --> 00:36:37,560 For the first time, 982 00:36:37,560 --> 00:36:38,840 the inhabitants of Earth could 983 00:36:38,840 --> 00:36:41,360 see their world from above. 984 00:36:41,360 --> 00:36:42,880 The whole Earth. 985 00:36:42,880 --> 00:36:44,920 The Earth in color. 986 00:36:44,920 --> 00:36:46,560 The Earth, as an exquisite 987 00:36:46,560 --> 00:36:49,000 spinning white and blue ball, 988 00:36:49,000 --> 00:36:53,480 set against the vast darkness of space. 989 00:36:53,480 --> 00:36:57,000 Those images helped awaken our 990 00:36:57,000 --> 00:37:01,520 slumbering planetary consciousness. 991 00:37:01,520 --> 00:37:04,200 They provide incontestable 992 00:37:04,200 --> 00:37:06,040 evidence that we all share 993 00:37:06,040 --> 00:37:09,120 the same vulnerable planet. 994 00:37:09,120 --> 00:37:11,640 They remind us of what's 995 00:37:11,640 --> 00:37:15,040 important and what's not. 996 00:37:15,040 --> 00:37:16,040 We may have found that 997 00:37:16,040 --> 00:37:18,640 perspective just in time, just 998 00:37:18,640 --> 00:37:20,480 as our technology threatens the 999 00:37:20,480 --> 00:37:23,040 habitability of our world. 1000 00:37:23,040 --> 00:37:24,600 Whatever the reason we first 1001 00:37:24,600 --> 00:37:27,280 mustered the Apollo program, 1002 00:37:27,280 --> 00:37:29,880 however mired it was in Cold 1003 00:37:29,880 --> 00:37:31,400 War nationalism and the 1004 00:37:31,400 --> 00:37:34,240 instruments of death, the 1005 00:37:34,240 --> 00:37:37,200 inescapable recognition of the 1006 00:37:37,200 --> 00:37:38,000 unity and 1007 00:37:38,000 --> 00:37:40,680 The fragility of the Earth is 1008 00:37:40,680 --> 00:37:43,600 its clear and luminous 1009 00:37:43,600 --> 00:37:47,960 dividend, the unexpected final 1010 00:37:47,960 --> 00:37:50,760 gift of Apollo. 1011 00:37:50,760 --> 00:37:52,440 What began in deadly 1012 00:37:52,440 --> 00:37:55,000 competition has helped us to 1013 00:37:55,000 --> 00:37:58,120 see that global cooperation is 1014 00:37:58,120 --> 00:37:59,200 the essential 1015 00:37:59,200 --> 00:38:02,680 precondition for our survival. 1016 00:38:02,680 --> 00:38:06,280 Travel is broadening. 1017 00:38:06,280 --> 00:38:27,440 it's time to hit the road again. 1018 00:38:28,640 --> 00:38:31,440 The sky calls to us. 1019 00:38:31,440 --> 00:38:32,520 If we do not destroy 1020 00:38:32,520 --> 00:38:34,640 ourselves we will one 1021 00:38:34,640 --> 00:38:37,600 day venture to the stars. 1022 00:38:37,600 --> 00:38:38,560 There was a time when the 1023 00:38:38,560 --> 00:38:41,280 stars seemed an impenetrable mystery. 1024 00:38:41,280 --> 00:38:42,360 Today 1025 00:38:42,360 --> 00:38:44,800 we have begun to understand them. 1026 00:38:44,800 --> 00:38:46,680 In our personal lives also we 1027 00:38:46,680 --> 00:38:49,960 journey from ignorance to knowledge. 1028 00:38:49,960 --> 00:38:52,400 our individual growth reflects 1029 00:38:52,400 --> 00:38:54,920 the advancement of the species. 1030 00:38:54,920 --> 00:38:57,000 The exploration of the cosmos 1031 00:38:57,000 --> 00:39:05,400 is a voyage of self-discovery. 1032 00:39:05,400 --> 00:39:07,320 Every one of us begins life 1033 00:39:07,320 --> 00:39:09,520 with an open mind, a driving 1034 00:39:09,520 --> 00:39:15,480 curiosity, a sense of wonder. 1035 00:39:15,480 --> 00:39:17,720 Sometimes I think how lucky 1036 00:39:17,720 --> 00:39:20,160 we are to live in this time, 1037 00:39:20,160 --> 00:39:21,760 the first moment in human 1038 00:39:21,760 --> 00:39:24,160 history when we are, in fact, 1039 00:39:24,160 --> 00:39:26,000 visiting other worlds and 1040 00:39:26,000 --> 00:39:27,520 engaging in a deep 1041 00:39:27,520 --> 00:39:30,680 reconnaissance of the cosmos. But if 1042 00:39:30,680 --> 00:39:31,920 we had been born in a much 1043 00:39:31,920 --> 00:39:33,840 earlier age, no matter how 1044 00:39:33,840 --> 00:39:34,960 great our dedication, we 1045 00:39:34,960 --> 00:39:36,600 could not have understood what 1046 00:39:36,600 --> 00:39:39,800 the stars and planets are. 1047 00:39:39,800 --> 00:39:40,960 We would not have known 1048 00:39:40,960 --> 00:39:42,640 that there were other suns 1049 00:39:42,640 --> 00:39:45,480 and other worlds. 1050 00:39:45,480 --> 00:39:47,800 This is one of the great secrets 1051 00:39:47,800 --> 00:39:50,040 wrested from nature through a 1052 00:39:50,040 --> 00:39:51,400 million years of patient 1053 00:39:51,400 --> 00:39:57,000 observation and courageous thinking. 1054 00:39:57,000 --> 00:39:59,840 The ǃKung Bushmen of the 1055 00:39:59,840 --> 00:40:00,960 Kalahari Desert in the 1056 00:40:00,960 --> 00:40:03,000 Republic of Botswana 1057 00:40:03,000 --> 00:40:05,760 have an explanation of the Milky Way. 1058 00:40:05,760 --> 00:40:06,720 At their latitude, 1059 00:40:06,720 --> 00:40:09,400 it's often overhead. They call 1060 00:40:09,400 --> 00:40:13,160 it the backbone of night. 1061 00:40:13,160 --> 00:40:16,040 They believe it holds the sky up. 1062 00:40:16,040 --> 00:40:17,000 They believe that if not 1063 00:40:17,000 --> 00:40:19,360 for the Milky Way, pieces of 1064 00:40:19,360 --> 00:40:21,440 sky would come crashing down 1065 00:40:21,440 --> 00:40:23,160 at our feet. So the Milky Way 1066 00:40:23,160 --> 00:40:24,680 in their view as some 1067 00:40:24,680 --> 00:40:31,560 practical value, a backbone of night. 1068 00:40:31,560 --> 00:40:34,560 Later on, metaphors about 1069 00:40:34,560 --> 00:40:37,000 campfires, or backbones, 1070 00:40:37,000 --> 00:40:38,760 or holes through which the 1071 00:40:38,760 --> 00:40:40,720 flame could be seen 1072 00:40:40,720 --> 00:40:42,520 were replaced in most human 1073 00:40:42,520 --> 00:40:45,640 communities by another idea. 1074 00:40:45,640 --> 00:40:47,560 The powerful beings in the 1075 00:40:47,560 --> 00:40:51,080 sky were promoted to gods. 1076 00:40:51,080 --> 00:40:52,800 They were given names and 1077 00:40:52,800 --> 00:40:55,160 relatives and special 1078 00:40:55,160 --> 00:40:57,320 responsibilities for the cosmic 1079 00:40:57,320 --> 00:41:00,120 services they were expected to perform. 1080 00:41:00,120 --> 00:41:02,560 There was a god for every 1081 00:41:02,560 --> 00:41:04,200 human concern. 1082 00:41:04,200 --> 00:41:05,560 Gods ran nature. 1083 00:41:05,560 --> 00:41:07,320 Nothing happened without the direct 1084 00:41:07,320 --> 00:41:10,240 intervention of some god. 1085 00:41:10,240 --> 00:41:12,160 If the gods were happy, there 1086 00:41:12,160 --> 00:41:14,360 was plenty of food and humans 1087 00:41:14,360 --> 00:41:17,160 were happy. 1088 00:41:17,160 --> 00:41:19,040 But if something displeased 1089 00:41:19,040 --> 00:41:20,840 the gods, and it didn't take 1090 00:41:20,840 --> 00:41:24,760 much, the consequences were awesome. 1091 00:41:24,760 --> 00:41:28,080 Droughts, floods, storms, wars, 1092 00:41:28,080 --> 00:41:29,360 Earthquakes, volcanic 1093 00:41:29,360 --> 00:41:32,680 eruptions, epidemics. 1094 00:41:32,680 --> 00:41:34,040 The gods had 1095 00:41:34,040 --> 00:41:36,840 to be propitiated, and a vast 1096 00:41:36,840 --> 00:41:38,680 industry of priests arose to 1097 00:41:38,680 --> 00:41:42,040 make the gods less angry. 1098 00:41:42,040 --> 00:41:43,840 But because the gods were 1099 00:41:43,840 --> 00:41:45,760 capricious, you couldn't be 1100 00:41:45,760 --> 00:41:47,920 sure what they would do. 1101 00:41:47,920 --> 00:41:50,480 Nature was a mystery. 1102 00:41:50,480 --> 00:41:57,240 It was hard to understand the world. 1103 00:41:57,960 --> 00:42:00,560 Our ancestors groped in 1104 00:42:00,560 --> 00:42:02,200 darkness to make sense of 1105 00:42:02,200 --> 00:42:03,880 their surroundings. 1106 00:42:03,880 --> 00:42:06,120 Powerless before nature, they 1107 00:42:06,120 --> 00:42:08,800 invented rituals and myths. 1108 00:42:08,800 --> 00:42:12,680 some desperate, cruel, others 1109 00:42:12,680 --> 00:42:16,520 imaginative, benign. 1110 00:42:16,520 --> 00:42:18,040 The ancient Greeks explained 1111 00:42:18,040 --> 00:42:20,360 that diffuse band of 1112 00:42:20,360 --> 00:42:22,640 brightness in the night sky 1113 00:42:22,640 --> 00:42:24,400 as the milk of the goddess 1114 00:42:24,400 --> 00:42:27,200 Hera, squirted from her breast 1115 00:42:27,200 --> 00:42:28,720 across the heavens. 1116 00:42:28,720 --> 00:42:35,040 We still call it the Milky Way. 1117 00:42:35,040 --> 00:42:36,320 What do you do when you're 1118 00:42:36,320 --> 00:42:37,800 faced with several different 1119 00:42:37,800 --> 00:42:41,000 gods, each claiming the same territory? 1120 00:42:41,000 --> 00:42:42,680 The Babylonian Marduk and the 1121 00:42:42,680 --> 00:42:44,440 Greek Zeus were each 1122 00:42:44,440 --> 00:42:47,480 considered king of the gods, 1123 00:42:47,480 --> 00:42:49,800 master of the sky. 1124 00:42:49,800 --> 00:42:51,160 You might decide, since they 1125 00:42:51,160 --> 00:42:52,240 otherwise had rather different 1126 00:42:52,240 --> 00:42:54,000 attributes, that one of them 1127 00:42:54,000 --> 00:42:56,400 was merely invented by the priests. 1128 00:42:56,400 --> 00:42:59,560 But if one, why not both? 1129 00:42:59,560 --> 00:43:01,320 And so it was here that the 1130 00:43:01,320 --> 00:43:02,920 great idea arose, the 1131 00:43:02,920 --> 00:43:04,040 realization that there might 1132 00:43:04,040 --> 00:43:05,800 be a way to know the world 1133 00:43:05,800 --> 00:43:07,880 without the God hypothesis, 1134 00:43:07,880 --> 00:43:09,200 that there might be 1135 00:43:09,200 --> 00:43:11,840 principles, forces, laws of 1136 00:43:11,840 --> 00:43:13,440 nature, through which the 1137 00:43:13,440 --> 00:43:14,600 world might be understood 1138 00:43:14,600 --> 00:43:16,360 without attributing the fall 1139 00:43:16,360 --> 00:43:18,240 of every sparrow to the 1140 00:43:18,240 --> 00:43:22,200 direct intervention of Zeus. 1141 00:43:22,200 --> 00:43:27,160 Where are we? Who are we? 1142 00:43:27,160 --> 00:43:29,680 We find that we live on an 1143 00:43:29,680 --> 00:43:31,840 insignificant planet of a 1144 00:43:31,840 --> 00:43:35,800 humdrum star lost in a galaxy tucked 1145 00:43:35,800 --> 00:43:38,760 away in some forgotten corner 1146 00:43:38,760 --> 00:43:40,320 of a universe in which there 1147 00:43:40,320 --> 00:43:46,680 are far more galaxies than people. 1148 00:43:46,680 --> 00:43:48,920 We make our world significant 1149 00:43:48,920 --> 00:43:50,120 by the courage of our 1150 00:43:50,120 --> 00:43:52,360 questions and by the depth of 1151 00:43:52,360 --> 00:43:55,480 our answers. 1152 00:43:55,480 --> 00:43:57,360 We embarked on our journey to 1153 00:43:57,360 --> 00:44:00,480 the stars with a question 1154 00:44:00,480 --> 00:44:02,240 first framed in the 1155 00:44:02,240 --> 00:44:05,680 childhood of our species, and 1156 00:44:05,680 --> 00:44:09,520 in each generation asked anew 1157 00:44:09,520 --> 00:44:10,480 with undiminished 1158 00:44:10,480 --> 00:44:15,920 wonder, what are the stars? 1159 00:44:15,920 --> 00:44:17,800 And the answer is that the 1160 00:44:17,800 --> 00:44:19,160 stars are mighty 1161 00:44:19,160 --> 00:44:21,360 suns light-years away in the 1162 00:44:21,360 --> 00:44:24,800 depths of instellar space. 1163 00:44:24,800 --> 00:44:27,200 And around those suns 1164 00:44:27,200 --> 00:44:30,240 are there other planets. 1165 00:44:30,240 --> 00:44:32,600 And on those other worlds are 1166 00:44:32,600 --> 00:44:34,200 there beings who wonder 1167 00:44:34,200 --> 00:44:39,480 as we do. Think of how many stars and 1168 00:44:39,480 --> 00:44:42,400 planets and kinds of life there may be 1169 00:44:42,400 --> 00:44:48,920 in this vast and awesome universe. 1170 00:44:48,920 --> 00:44:52,240 Exploration is in our nature. 1171 00:44:52,240 --> 00:44:55,200 We began as wanderers and we 1172 00:44:55,200 --> 00:45:03,080 are wanderers still. 1173 00:45:03,080 --> 00:45:05,960 We have lingered long enough 1174 00:45:05,960 --> 00:45:09,000 on the shores of the cosmic ocean. 1175 00:45:09,000 --> 00:45:11,400 We are ready at last to set 1176 00:45:11,400 --> 00:45:26,960 sail for the stars. 1177 00:45:30,800 --> 00:45:32,640 There is one experience that 1178 00:45:32,640 --> 00:45:34,960 every human shares, of every 1179 00:45:34,960 --> 00:45:37,240 language and culture, the 1180 00:45:37,240 --> 00:45:39,480 experience of birth. 1181 00:45:39,480 --> 00:45:41,680 Our recollections of birth are 1182 00:45:41,680 --> 00:45:43,440 hazy at best. 1183 00:45:43,440 --> 00:45:46,080 They have the feel and aura, 1184 00:45:46,080 --> 00:45:48,280 not so much of memories as 1185 00:45:48,280 --> 00:45:52,360 of mystical transfigurations. 1186 00:45:52,360 --> 00:45:53,640 It would be astonishing if 1187 00:45:53,640 --> 00:45:56,400 this profound early experience 1188 00:45:56,400 --> 00:45:58,320 did not influence our myths and 1189 00:45:58,320 --> 00:46:00,600 religions, our philosophy, and 1190 00:46:00,600 --> 00:46:02,160 our science. 1191 00:46:02,160 --> 00:46:05,320 The birth of a child evokes the mystery 1192 00:46:05,320 --> 00:46:07,360 of other origins, the 1193 00:46:07,360 --> 00:46:10,200 beginnings and ends of worlds, 1194 00:46:10,200 --> 00:46:16,520 infinity and eternity. How did 1195 00:46:16,520 --> 00:46:20,160 the universe arise? 1196 00:46:20,160 --> 00:46:24,080 What was around before that? 1197 00:46:24,080 --> 00:46:25,600 Might there have been no 1198 00:46:25,600 --> 00:46:27,600 beginning could the universe 1199 00:46:27,600 --> 00:46:31,120 be infinitely old? 1200 00:46:31,120 --> 00:46:32,280 The current scientific 1201 00:46:32,280 --> 00:46:33,680 story of the origin of the 1202 00:46:33,680 --> 00:46:35,560 universe begins with an 1203 00:46:35,560 --> 00:46:36,920 explosion which made 1204 00:46:36,920 --> 00:46:39,200 space itself expand. 1205 00:46:39,200 --> 00:46:41,240 About 15 billion years ago 1206 00:46:41,240 --> 00:46:42,640 all the matter and energy that 1207 00:46:42,640 --> 00:46:44,040 today make up the observable 1208 00:46:44,040 --> 00:46:46,240 universe were concentrated into 1209 00:46:46,240 --> 00:46:47,400 a space smaller 1210 00:46:47,400 --> 00:46:49,600 than the head of a pin. 1211 00:46:49,600 --> 00:46:51,760 The cosmos blew apart in one 1212 00:46:51,760 --> 00:46:53,480 inconceivably colossal 1213 00:46:53,480 --> 00:46:56,240 explosion, the Big Bang, and 1214 00:46:56,240 --> 00:46:58,040 the stuff of the universe 1215 00:46:58,040 --> 00:46:59,200 together with the fabric of 1216 00:46:59,200 --> 00:47:01,320 space itself began expanding 1217 00:47:01,320 --> 00:47:04,080 in all directions as they do today. 1218 00:47:04,080 --> 00:47:04,560 The early 1219 00:47:04,560 --> 00:47:07,000 cosmos was everywhere white 1220 00:47:07,000 --> 00:47:08,960 hot, but as time passed the 1221 00:47:08,960 --> 00:47:10,320 radiation expanded and 1222 00:47:10,320 --> 00:47:12,360 cooled and in ordinary visible 1223 00:47:12,360 --> 00:47:16,480 light space became dark as it is today. 1224 00:47:16,480 --> 00:47:18,600 But then little pockets of gas 1225 00:47:18,600 --> 00:47:20,160 began to grow. 1226 00:47:20,160 --> 00:47:23,200 Tendrils of gossamer clouds formed. 1227 00:47:23,200 --> 00:47:25,720 Colonies of great, lumbering, 1228 00:47:25,720 --> 00:47:26,840 slowly spinning things, 1229 00:47:27,800 --> 00:47:30,400 steadily brightening, each a kind of 1230 00:47:30,400 --> 00:47:32,200 beast composed of a hundred 1231 00:47:32,200 --> 00:47:37,960 billion shining points. 1232 00:47:37,960 --> 00:47:40,120 The largest recognizable structures 1233 00:47:40,120 --> 00:47:42,400 in the universe had formed. 1234 00:47:42,400 --> 00:47:43,320 We see them today. 1235 00:47:43,320 --> 00:47:45,720 We ourselves inhabit some lost 1236 00:47:45,720 --> 00:47:47,000 corner of one. 1237 00:47:47,000 --> 00:47:49,520 We call them the galaxies. 1238 00:47:49,520 --> 00:47:52,240 We inhabit a universe of galaxies. 1239 00:47:52,240 --> 00:47:54,840 There are unstructured blobs, 1240 00:47:54,840 --> 00:47:56,840 the irregular galaxies, 1241 00:47:56,840 --> 00:47:59,640 globular or elliptical galaxies 1242 00:47:59,640 --> 00:48:00,600 and the graceful 1243 00:48:00,600 --> 00:48:05,000 blue arms of spiral galaxies. 1244 00:48:05,000 --> 00:48:06,360 We've been investigating the 1245 00:48:06,360 --> 00:48:07,520 galaxies, their 1246 00:48:07,520 --> 00:48:09,760 origins, evolution and motions 1247 00:48:09,760 --> 00:48:11,600 for less than a century. 1248 00:48:11,600 --> 00:48:14,040 These studies extend our 1249 00:48:14,040 --> 00:48:15,280 understanding to the farthest 1250 00:48:15,280 --> 00:48:18,160 reaches of the universe. 1251 00:48:18,160 --> 00:48:19,920 We view the cosmos on the 1252 00:48:19,920 --> 00:48:22,240 grandest of scales, the 1253 00:48:22,240 --> 00:48:24,160 majesty of the galaxies is 1254 00:48:24,160 --> 00:48:26,760 revealed by science. 1255 00:48:29,320 --> 00:48:31,280 The galaxies reveal a 1256 00:48:31,280 --> 00:48:34,080 universal order, beauty, but 1257 00:48:34,080 --> 00:48:36,400 also violence on a scale 1258 00:48:36,400 --> 00:48:38,720 never before imagined. 1259 00:48:38,720 --> 00:48:40,440 The universe seems neither 1260 00:48:40,440 --> 00:48:43,720 benign nor hostile, merely 1261 00:48:43,720 --> 00:48:46,400 indifferent to the concerns of such 1262 00:48:46,400 --> 00:48:52,320 creatures as we. 1263 00:48:52,320 --> 00:48:53,600 If the general picture, 1264 00:48:53,600 --> 00:48:55,400 however, of a Big Bang 1265 00:48:55,400 --> 00:48:56,440 followed by an expanding 1266 00:48:56,440 --> 00:48:58,960 universe is correct, 1267 00:48:58,960 --> 00:49:00,840 what happened before that? 1268 00:49:00,840 --> 00:49:02,720 Was the universe devoid of 1269 00:49:02,720 --> 00:49:05,200 all matter, and then the matter 1270 00:49:05,200 --> 00:49:07,120 suddenly, somehow, created? 1271 00:49:07,120 --> 00:49:09,280 How did that happen? 1272 00:49:09,280 --> 00:49:10,840 In many cultures, the 1273 00:49:10,840 --> 00:49:12,840 customary answer is that 1274 00:49:12,840 --> 00:49:15,520 a god or gods created the 1275 00:49:15,520 --> 00:49:17,920 universe out of nothing. 1276 00:49:17,920 --> 00:49:19,200 But if we wish to pursue 1277 00:49:19,200 --> 00:49:21,560 this question courageously, 1278 00:49:21,560 --> 00:49:23,360 We must, of course, ask the 1279 00:49:23,360 --> 00:49:24,720 next question. 1280 00:49:24,720 --> 00:49:26,840 Where did God come from? 1281 00:49:26,840 --> 00:49:28,880 If we decide that this is an 1282 00:49:28,880 --> 00:49:29,960 unanswerable question, 1283 00:49:29,960 --> 00:49:32,000 why not save a step and 1284 00:49:32,000 --> 00:49:33,160 conclude that the origin of 1285 00:49:33,160 --> 00:49:34,720 the universe is an 1286 00:49:34,720 --> 00:49:36,560 unanswerable question? 1287 00:49:36,560 --> 00:49:40,320 Or, if we say that God always existed, 1288 00:49:40,320 --> 00:49:41,760 why not save a step and 1289 00:49:41,760 --> 00:49:43,560 conclude that the universe 1290 00:49:43,560 --> 00:49:44,720 always existed? 1291 00:49:44,720 --> 00:49:45,840 There's no need for a 1292 00:49:45,840 --> 00:49:47,560 creation, it was always here. 1293 00:49:47,560 --> 00:49:49,640 These are not easy questions. 1294 00:49:49,640 --> 00:49:51,280 Cosmology brings us face to 1295 00:49:51,280 --> 00:49:53,160 face with the deepest 1296 00:49:53,160 --> 00:49:55,640 mysteries, questions that were once 1297 00:49:55,640 --> 00:49:58,240 treated only in religion. 1298 00:50:04,080 --> 00:50:05,920 Every human generation has 1299 00:50:05,920 --> 00:50:07,760 asked about the origin and 1300 00:50:07,760 --> 00:50:09,720 fate of the cosmos. 1301 00:50:09,720 --> 00:50:12,000 Ours is the first generation 1302 00:50:12,000 --> 00:50:14,560 with a real chance of finding 1303 00:50:14,560 --> 00:50:17,080 some of the answers. 1304 00:50:17,080 --> 00:50:19,000 One way or another, we are 1305 00:50:19,000 --> 00:50:26,640 poised of forever. 1306 00:50:48,480 --> 00:50:49,720 In the 17th century, there 1307 00:50:49,720 --> 00:50:51,520 was still some hope that, 1308 00:50:51,520 --> 00:50:52,960 even if the Earth was not the center 1309 00:50:52,960 --> 00:50:54,640 of the universe, it might be 1310 00:50:54,640 --> 00:50:57,080 the only world. 1311 00:50:57,080 --> 00:50:58,120 After millennia of 1312 00:50:58,120 --> 00:51:00,080 philosophical debate, the issue 1313 00:51:00,080 --> 00:51:02,480 was settled decisively in favor of what 1314 00:51:02,480 --> 00:51:05,720 was called the plurality of worlds. 1315 00:51:05,720 --> 00:51:06,680 They might be profoundly 1316 00:51:06,680 --> 00:51:08,440 different from our planet. 1317 00:51:08,440 --> 00:51:09,400 None of them might be as 1318 00:51:09,400 --> 00:51:11,400 congenial for life, but the 1319 00:51:11,400 --> 00:51:14,800 Earth was hardly the only one. 1320 00:51:14,800 --> 00:51:15,840 This was the next in the 1321 00:51:15,840 --> 00:51:17,920 series of great demotions, 1322 00:51:17,920 --> 00:51:20,180 downlifting experiences, 1323 00:51:20,180 --> 00:51:22,240 demonstrations of our apparent 1324 00:51:22,240 --> 00:51:25,800 insignificance, wounds that science has 1325 00:51:25,800 --> 00:51:28,800 delivered to human pride. 1326 00:51:28,800 --> 00:51:30,760 Well, some hoped, even if the 1327 00:51:30,760 --> 00:51:31,400 Earth isn't at the 1328 00:51:31,400 --> 00:51:33,880 center of the universe, the Sun is. 1329 00:51:33,880 --> 00:51:37,520 The Sun is our Sun, so the Earth is 1330 00:51:37,520 --> 00:51:38,920 approximately at the center of 1331 00:51:38,920 --> 00:51:40,600 the universe. 1332 00:51:40,600 --> 00:51:42,400 But by the 19th century, 1333 00:51:42,400 --> 00:51:43,720 Observational astronomy had 1334 00:51:43,720 --> 00:51:45,960 made it clear that the Sun 1335 00:51:45,960 --> 00:51:49,640 is but one lonely star in a great 1336 00:51:49,640 --> 00:51:51,920 self-gravitating assemblage of 1337 00:51:51,920 --> 00:51:55,640 suns called the Milky Way galaxy. 1338 00:51:55,640 --> 00:51:57,080 Far from being at the center 1339 00:51:57,080 --> 00:51:59,440 of the galaxy, our Sun, with 1340 00:51:59,440 --> 00:52:02,280 its entourage of dim and tiny 1341 00:52:02,280 --> 00:52:05,080 planets, lies in an 1342 00:52:05,080 --> 00:52:07,120 undistinguished sector of an 1343 00:52:07,120 --> 00:52:09,200 obscure spiral arm. 1344 00:52:09,200 --> 00:52:11,760 we are 30,000 light-years from 1345 00:52:11,760 --> 00:52:14,000 the center. 1346 00:52:14,000 --> 00:52:18,360 Well, our Milky Way is the only galaxy. 1347 00:52:18,360 --> 00:52:20,640 The Milky Way galaxy is in 1348 00:52:20,640 --> 00:52:22,360 fact one of billions, 1349 00:52:22,360 --> 00:52:23,880 perhaps hundreds of billions, 1350 00:52:23,880 --> 00:52:25,800 of galaxies notable 1351 00:52:25,800 --> 00:52:27,840 neither in mass, nor in 1352 00:52:27,840 --> 00:52:29,440 brightness, nor in how 1353 00:52:29,440 --> 00:52:32,200 its stars are configured and arrayed. 1354 00:52:32,200 --> 00:52:33,320 Some modern 1355 00:52:33,320 --> 00:52:35,720 deep-sky photographs show more 1356 00:52:35,720 --> 00:52:38,240 galaxies beyond the Milky Way 1357 00:52:38,240 --> 00:52:41,240 than stars within the Milky Way. 1358 00:52:41,240 --> 00:52:44,600 Every one of them is an island universe 1359 00:52:44,600 --> 00:52:46,840 containing perhaps a hundred 1360 00:52:46,840 --> 00:52:49,280 billion suns. 1361 00:52:49,280 --> 00:52:51,680 Such an image is a profound 1362 00:52:51,680 --> 00:52:55,400 sermon on humility. 1363 00:52:55,400 --> 00:52:57,000 Well then, at least our 1364 00:52:57,000 --> 00:52:58,040 galaxy is at the center of 1365 00:52:58,040 --> 00:52:59,240 the universe. 1366 00:52:59,240 --> 00:53:02,040 Nope, this is wrong too. 1367 00:53:02,040 --> 00:53:03,000 When the expansion of the 1368 00:53:03,000 --> 00:53:04,000 universe was first 1369 00:53:04,000 --> 00:53:05,520 discovered, many people 1370 00:53:05,520 --> 00:53:07,000 naturally gravitated to the 1371 00:53:07,000 --> 00:53:07,880 notion that the Milky 1372 00:53:07,880 --> 00:53:09,040 way was at the center of the 1373 00:53:09,040 --> 00:53:10,840 expansion, and all the other 1374 00:53:10,840 --> 00:53:13,520 galaxies running away from us. 1375 00:53:13,520 --> 00:53:14,560 We now recognize that 1376 00:53:14,560 --> 00:53:16,040 astronomers on any galaxy 1377 00:53:16,040 --> 00:53:17,000 would see all the others 1378 00:53:17,000 --> 00:53:17,760 running away from 1379 00:53:17,760 --> 00:53:20,560 them unless they were very careful. 1380 00:53:20,560 --> 00:53:21,640 They would all conclude that 1381 00:53:21,640 --> 00:53:22,720 they were at the center 1382 00:53:22,720 --> 00:53:24,880 of the universe. 1383 00:53:24,880 --> 00:53:26,560 There is in fact no center 1384 00:53:26,560 --> 00:53:28,440 to the expansion, no point of 1385 00:53:28,440 --> 00:53:30,400 origin of the Big Bang. 1386 00:53:30,400 --> 00:53:31,800 Well, even if there are 1387 00:53:31,800 --> 00:53:32,760 hundreds of billions of 1388 00:53:32,760 --> 00:53:33,840 galaxies, each with hundreds 1389 00:53:33,840 --> 00:53:35,640 of billions of stars, no 1390 00:53:35,640 --> 00:53:38,400 other star has planets. 1391 00:53:38,400 --> 00:53:39,680 If there are no other planets 1392 00:53:39,680 --> 00:53:41,000 beyond our solar system, 1393 00:53:41,000 --> 00:53:41,800 perhaps there is no other 1394 00:53:41,800 --> 00:53:43,080 life in the universe. 1395 00:53:43,080 --> 00:53:46,400 Our uniqueness might then be saved. 1396 00:53:46,400 --> 00:53:48,560 Today we have firm evidence 1397 00:53:48,560 --> 00:53:49,800 for at least three planets 1398 00:53:49,800 --> 00:53:52,840 orbiting an extremely dense star, 1399 00:53:52,840 --> 00:53:54,680 and we found for more than 1400 00:53:54,680 --> 00:53:56,000 half the stars with masses 1401 00:53:56,000 --> 00:53:57,840 like the Sun's, that early in 1402 00:53:57,840 --> 00:53:59,400 their careers, they're 1403 00:53:59,400 --> 00:54:01,720 surrounded by great disks of 1404 00:54:01,720 --> 00:54:03,840 gas and dust, out of which planets 1405 00:54:03,840 --> 00:54:05,480 seem to form. 1406 00:54:05,480 --> 00:54:06,840 Other planetary systems now 1407 00:54:06,840 --> 00:54:08,760 look to be a cosmic 1408 00:54:08,760 --> 00:54:11,680 commonplace, maybe even 1409 00:54:11,680 --> 00:54:14,240 worlds something like the Earth. 1410 00:54:14,240 --> 00:54:16,080 Well, if our position in 1411 00:54:16,080 --> 00:54:17,320 space doesn't reveal our 1412 00:54:17,320 --> 00:54:19,480 special role, our position in 1413 00:54:19,480 --> 00:54:20,760 time does. 1414 00:54:20,760 --> 00:54:21,840 We've been in the universe 1415 00:54:21,840 --> 00:54:23,640 since the beginning, 1416 00:54:23,640 --> 00:54:25,120 Give or take a few days, 1417 00:54:25,120 --> 00:54:26,480 we've been given special 1418 00:54:26,480 --> 00:54:31,360 responsibilities by the Creator. 1419 00:54:31,360 --> 00:54:32,560 The radioactive dating of 1420 00:54:32,560 --> 00:54:34,560 rocks, the abundance of impact 1421 00:54:34,560 --> 00:54:37,000 craters on many worlds, the evolution 1422 00:54:37,000 --> 00:54:38,560 of the stars, and the 1423 00:54:38,560 --> 00:54:40,080 expansion of the universe each 1424 00:54:40,080 --> 00:54:41,920 provides compelling and 1425 00:54:41,920 --> 00:54:44,160 independent evidence 1426 00:54:44,160 --> 00:54:45,240 that our universe is many 1427 00:54:45,240 --> 00:54:47,240 billions of years old. 1428 00:54:47,240 --> 00:54:48,480 Despite the confident 1429 00:54:48,480 --> 00:54:49,960 assertions of revered 1430 00:54:49,960 --> 00:54:51,920 theologians that a world so 1431 00:54:51,920 --> 00:54:53,800 old directly contradicts 1432 00:54:53,800 --> 00:54:55,720 the word of God, and that at 1433 00:54:55,720 --> 00:54:57,160 any rate information on the 1434 00:54:57,160 --> 00:54:59,400 antiquity of the world is inaccessible 1435 00:54:59,400 --> 00:55:00,840 except to faith. 1436 00:55:00,840 --> 00:55:01,960 These lines of evidence as 1437 00:55:01,960 --> 00:55:02,760 well would have to be 1438 00:55:02,760 --> 00:55:04,440 manufactured by a deceptive 1439 00:55:04,440 --> 00:55:05,120 and malicious 1440 00:55:05,120 --> 00:55:07,520 deity unless the world is 1441 00:55:07,520 --> 00:55:09,800 much older than the literalists in the 1442 00:55:09,800 --> 00:55:11,120 Judeo-Christian-Islamic 1443 00:55:11,120 --> 00:55:14,280 religion suppose. 1444 00:55:14,280 --> 00:55:17,720 Ages rolled by before the Earth began. 1445 00:55:17,720 --> 00:55:19,040 More ages will run their 1446 00:55:19,040 --> 00:55:22,120 course before it is destroyed. 1447 00:55:22,120 --> 00:55:23,360 A distinction needs to be 1448 00:55:23,360 --> 00:55:25,200 drawn between how old the 1449 00:55:25,200 --> 00:55:28,560 Earth is and how old the universe is. 1450 00:55:28,560 --> 00:55:30,040 The immense interval of time 1451 00:55:30,040 --> 00:55:30,960 between the origin of the 1452 00:55:30,960 --> 00:55:33,840 universe and our epoch was two-thirds 1453 00:55:33,840 --> 00:55:36,680 over before the Earth came to be. 1454 00:55:36,680 --> 00:55:38,200 Some stars and planetary 1455 00:55:38,200 --> 00:55:39,920 systems are billions of years 1456 00:55:39,920 --> 00:55:42,360 younger, others billions of 1457 00:55:42,360 --> 00:55:43,920 years older. 1458 00:55:43,920 --> 00:55:46,791 But in Genesis chapter 1 1459 00:55:46,791 --> 00:55:47,600 verse 1, the universe and the 1460 00:55:47,600 --> 00:55:50,200 Earth are created on the same day. 1461 00:55:50,200 --> 00:55:53,840 As for humans, we're latecomers. 1462 00:55:53,840 --> 00:55:55,360 We appear in the last instant 1463 00:55:55,360 --> 00:55:56,240 of cosmic time. 1464 00:55:57,160 --> 00:55:58,240 The history of the universe 1465 00:55:58,240 --> 00:56:04,320 till now was 99.998% over, 1466 00:56:04,320 --> 00:56:06,280 before our species arrived on 1467 00:56:06,280 --> 00:56:07,840 the scene. 1468 00:56:07,840 --> 00:56:10,320 In that vast sweep of eons, 1469 00:56:10,320 --> 00:56:11,600 we could not have assumed any 1470 00:56:11,600 --> 00:56:13,320 special responsibilities 1471 00:56:13,320 --> 00:56:15,720 for our planet or life or 1472 00:56:15,720 --> 00:56:17,120 anything else. 1473 00:56:17,120 --> 00:56:19,440 We were not here. 1474 00:56:19,440 --> 00:56:21,240 Our common sense intuitions 1475 00:56:21,240 --> 00:56:22,840 can be mistaken. 1476 00:56:22,840 --> 00:56:25,840 Our preferences don't count. We 1477 00:56:25,840 --> 00:56:28,360 do not live in a privileged 1478 00:56:28,360 --> 00:56:31,480 reference frame. 1479 00:56:31,480 --> 00:56:34,480 Well, even if our position, our 1480 00:56:34,480 --> 00:56:36,520 epoch, our motion, and our 1481 00:56:36,520 --> 00:56:39,240 world are not unique, maybe we are. 1482 00:56:39,240 --> 00:56:39,880 We're different from 1483 00:56:39,880 --> 00:56:41,320 the other animals. 1484 00:56:41,320 --> 00:56:43,520 We're specially created. 1485 00:56:43,520 --> 00:56:45,320 The particular devotion of the 1486 00:56:45,320 --> 00:56:46,560 creator of the universe is 1487 00:56:46,560 --> 00:56:49,200 evident in us. 1488 00:56:49,200 --> 00:56:51,680 This position was passionately 1489 00:56:51,680 --> 00:56:52,880 defended on religious and 1490 00:56:52,880 --> 00:56:55,240 other grounds, but in the middle 1491 00:56:55,240 --> 00:56:56,800 19th century Charles Darwin 1492 00:56:56,800 --> 00:56:58,920 showed convincingly how one 1493 00:56:58,920 --> 00:57:01,600 species can evolve into another by 1494 00:57:01,600 --> 00:57:03,800 entirely natural processes 1495 00:57:03,800 --> 00:57:04,680 which come down to the 1496 00:57:04,680 --> 00:57:07,160 heartless business of nature saving 1497 00:57:07,160 --> 00:57:09,040 the heredities that work and 1498 00:57:09,040 --> 00:57:12,200 rejecting those that don't. 1499 00:57:12,200 --> 00:57:14,520 Man, in his arrogance, thinks 1500 00:57:14,520 --> 00:57:17,400 himself a great work, worthy 1501 00:57:17,400 --> 00:57:20,520 of the interposition of a deity. 1502 00:57:20,520 --> 00:57:22,080 More humble, and I think 1503 00:57:22,080 --> 00:57:24,680 truer, to consider him created 1504 00:57:24,680 --> 00:57:26,160 from animals. 1505 00:57:26,680 --> 00:57:28,120 The profound and intimate 1506 00:57:28,120 --> 00:57:29,360 connections of humans with the 1507 00:57:29,360 --> 00:57:31,440 other life-forms on Earth has been 1508 00:57:31,440 --> 00:57:33,200 compellingly demonstrated in 1509 00:57:33,200 --> 00:57:34,920 the late twentieth century by 1510 00:57:34,920 --> 00:57:39,480 the new science of molecular biology." 1511 00:57:39,480 --> 00:57:41,520 Well, even if we're closely 1512 00:57:41,520 --> 00:57:42,600 related to some of the other 1513 00:57:42,600 --> 00:57:44,480 animals, we're different. 1514 00:57:44,480 --> 00:57:47,080 Not just in degree, but in kind. 1515 00:57:47,080 --> 00:57:49,080 On what really matters, 1516 00:57:49,080 --> 00:57:51,960 reasoning, self-consciousness, 1517 00:57:51,960 --> 00:57:54,960 tool-making, ethics, altruism, 1518 00:57:54,960 --> 00:57:55,560 religion, 1519 00:57:55,560 --> 00:57:59,440 language, nobility of character. 1520 00:57:59,440 --> 00:58:00,680 Human uniqueness has been 1521 00:58:00,680 --> 00:58:04,400 exaggerated, sometimes grossly so. 1522 00:58:04,400 --> 00:58:06,080 Chimps reason, are 1523 00:58:06,080 --> 00:58:07,600 self-conscious, make tools, 1524 00:58:07,600 --> 00:58:10,400 show devotion, and so on. 1525 00:58:10,400 --> 00:58:12,960 Chimps and humans have 99.6% 1526 00:58:12,960 --> 00:58:16,840 of their active genes in common. 1527 00:58:16,840 --> 00:58:19,480 Okay, maybe we're not much. 1528 00:58:19,480 --> 00:58:21,160 Maybe we're humiliatingly 1529 00:58:21,160 --> 00:58:22,720 related to apes. 1530 00:58:22,720 --> 00:58:24,720 But at least we're the best there is. 1531 00:58:24,720 --> 00:58:26,720 God and angels aside, we're 1532 00:58:26,720 --> 00:58:28,040 the only intelligent beings in 1533 00:58:28,040 --> 00:58:30,880 the universe. 1534 00:58:30,880 --> 00:58:32,160 But the simple fact is that 1535 00:58:32,160 --> 00:58:33,000 we have not yet found 1536 00:58:33,000 --> 00:58:34,440 extraterrestrial life. 1537 00:58:34,440 --> 00:58:35,720 We're in the earliest stages 1538 00:58:35,720 --> 00:58:36,800 of looking. 1539 00:58:36,800 --> 00:58:39,040 The question is wide open. 1540 00:58:39,040 --> 00:58:41,320 If I had to guess, especially 1541 00:58:41,320 --> 00:58:42,960 considering our long sequence 1542 00:58:42,960 --> 00:58:45,720 of failed chauvinisms, I'd 1543 00:58:45,720 --> 00:58:46,760 guess that the universe is 1544 00:58:46,760 --> 00:58:48,560 filled with beings far more 1545 00:58:48,560 --> 00:58:50,640 intelligent, far more advanced 1546 00:58:50,640 --> 00:58:52,320 than we are. 1547 00:58:52,320 --> 00:58:55,320 But, of course, I might be wrong. 1548 00:58:55,320 --> 00:58:56,760 Such a conclusion is at best 1549 00:58:56,760 --> 00:58:58,640 based on a plausibility 1550 00:58:58,640 --> 00:59:00,480 argument, derived from the 1551 00:59:00,480 --> 00:59:01,640 numbers of planets, 1552 00:59:01,640 --> 00:59:03,280 the ubiquity of organic 1553 00:59:03,280 --> 00:59:05,120 matter, the immense time 1554 00:59:05,120 --> 00:59:06,720 scales available for evolution, 1555 00:59:06,720 --> 00:59:07,960 and so on. 1556 00:59:07,960 --> 00:59:10,440 It's not a scientific demonstration. 1557 00:59:10,440 --> 00:59:11,480 The question is among the 1558 00:59:11,480 --> 00:59:14,160 most fascinating in all of science. 1559 00:59:14,160 --> 00:59:15,480 We are just developing the 1560 00:59:15,480 --> 00:59:18,880 tools to treat it seriously. 1561 00:59:18,880 --> 00:59:19,960 What about the related matter 1562 00:59:19,960 --> 00:59:21,160 of whether we are capable of 1563 00:59:21,160 --> 00:59:22,840 creating intelligences smarter 1564 00:59:22,840 --> 00:59:24,600 than ourselves. 1565 00:59:24,600 --> 00:59:26,080 Computers routinely do 1566 00:59:26,080 --> 00:59:27,680 mathematics that no unaided 1567 00:59:27,680 --> 00:59:30,080 human can manage, outperform 1568 00:59:30,080 --> 00:59:31,640 world champions in checkers 1569 00:59:31,640 --> 00:59:34,440 and grandmasters in chess, 1570 00:59:34,440 --> 00:59:35,800 speak and understand English and 1571 00:59:35,800 --> 00:59:37,280 other languages, write 1572 00:59:37,280 --> 00:59:38,640 presentable short stories and 1573 00:59:38,640 --> 00:59:41,000 musical compositions, learn from 1574 00:59:41,000 --> 00:59:43,560 their mistakes, and competently 1575 00:59:43,560 --> 00:59:47,040 pilot ships, airplanes, and spacecraft. 1576 00:59:47,040 --> 00:59:49,200 Their abilities steadily improve. 1577 00:59:49,200 --> 00:59:52,400 They're getting smaller, faster, and cheaper. 1578 00:59:52,400 --> 00:59:53,800 Every year the tide of 1579 00:59:53,800 --> 00:59:56,160 scientific advance laps a 1580 00:59:56,160 --> 00:59:58,240 little further ashore on the 1581 00:59:58,240 --> 00:59:59,680 island of human and collectual 1582 00:59:59,680 --> 01:00:00,760 uniqueness 1583 01:00:00,760 --> 01:00:04,800 with its embattled castaways. 1584 01:00:04,800 --> 01:00:06,120 The long-standing view, as 1585 01:00:06,120 --> 01:00:08,040 summarized by the philosopher Immanuel 1586 01:00:08,040 --> 01:00:12,520 Kant, that without man the 1587 01:00:12,520 --> 01:00:14,080 whole of creation would be a 1588 01:00:14,080 --> 01:00:17,040 mere wilderness, a thing in vain, 1589 01:00:17,040 --> 01:00:19,720 and have no final end is 1590 01:00:19,720 --> 01:00:24,000 revealed to be self-indulgent folly. 1591 01:00:24,000 --> 01:00:24,880 A principle of 1592 01:00:24,880 --> 01:00:27,640 mediocrity seems to apply to 1593 01:00:27,640 --> 01:00:30,080 all our circumstances. 1594 01:00:30,080 --> 01:00:31,360 We would not have known 1595 01:00:31,360 --> 01:00:33,000 beforehand that the evidence 1596 01:00:33,000 --> 01:00:34,320 would be so repeatedly and 1597 01:00:34,320 --> 01:00:37,240 thoroughly incompatible 1598 01:00:37,240 --> 01:00:38,160 with the proposition that 1599 01:00:38,160 --> 01:00:40,040 human beings are at center 1600 01:00:40,040 --> 01:00:43,520 stage in the universe. But 1601 01:00:43,520 --> 01:00:45,160 Most of the debates have now 1602 01:00:45,160 --> 01:00:48,200 been settled decisively 1603 01:00:48,200 --> 01:00:50,080 in favor of a position that, 1604 01:00:50,080 --> 01:00:51,400 however painful, 1605 01:00:51,400 --> 01:00:53,280 can be encapsulated in a 1606 01:00:53,280 --> 01:00:55,080 single sentence. 1607 01:00:55,080 --> 01:00:56,360 We have not been given the 1608 01:00:56,360 --> 01:01:00,200 lead in the cosmic drama. 1609 01:01:00,200 --> 01:01:02,360 Perhaps someone else has. 1610 01:01:02,360 --> 01:01:04,480 Perhaps no one else has. 1611 01:01:04,480 --> 01:01:06,640 In either case, we have good 1612 01:01:06,640 --> 01:01:15,320 reason for humility. 1613 01:01:15,320 --> 01:01:17,880 When my grandparents were children, 1614 01:01:17,880 --> 01:01:19,680 The electric light, the 1615 01:01:19,680 --> 01:01:22,600 automobile, the airplane, and 1616 01:01:22,600 --> 01:01:26,200 the radio were stupefying technological 1617 01:01:26,200 --> 01:01:29,840 advances, the wonders of the age. 1618 01:01:29,840 --> 01:01:31,640 But in that same time, around 1619 01:01:31,640 --> 01:01:33,920 the turn of the last century, 1620 01:01:33,920 --> 01:01:35,360 there were two men who foresaw 1621 01:01:35,360 --> 01:01:37,280 other far more ambitious 1622 01:01:37,280 --> 01:01:39,920 inventions, Konstantin 1623 01:01:39,920 --> 01:01:44,200 Tsiolkovsky and Robert Goddard. 1624 01:01:44,200 --> 01:01:46,480 They dreamt of using rockets 1625 01:01:46,480 --> 01:01:49,760 to journey to the planets and 1626 01:01:49,760 --> 01:01:52,040 the stars. 1627 01:01:52,040 --> 01:01:54,160 Step by step, they worked out 1628 01:01:54,160 --> 01:01:56,120 the fundamental physics and 1629 01:01:56,120 --> 01:01:58,360 many of the details. 1630 01:01:58,360 --> 01:02:02,920 Gradually, their machines took shape. 1631 01:02:02,920 --> 01:02:05,000 Ultimately, their dream 1632 01:02:05,000 --> 01:02:09,120 proved infectious. 1633 01:02:09,120 --> 01:02:11,680 A generation later, inspired 1634 01:02:11,680 --> 01:02:14,280 by Tsiolkovsky and Goddard, 1635 01:02:14,280 --> 01:02:17,000 Werner von Braun was constructing 1636 01:02:17,000 --> 01:02:18,360 the first rocket capable of 1637 01:02:18,360 --> 01:02:22,640 reaching the edge of space, the V-2. 1638 01:02:22,640 --> 01:02:25,920 But in one of those ironies 1639 01:02:25,920 --> 01:02:26,760 with which the twentieth 1640 01:02:26,760 --> 01:02:30,760 century is replete, von Braun was 1641 01:02:30,760 --> 01:02:34,520 building it for the Nazis. 1642 01:02:34,520 --> 01:02:35,400 as an instrument of 1643 01:02:35,400 --> 01:02:36,600 indiscriminate slaughter of 1644 01:02:36,600 --> 01:02:39,160 civilians, as a vengeance 1645 01:02:39,160 --> 01:02:42,040 weapon for Hitler. 1646 01:02:42,040 --> 01:02:43,720 The rocket factories staffed 1647 01:02:43,720 --> 01:02:46,440 with slave labor, untold human 1648 01:02:46,440 --> 01:02:48,200 suffering exacted in the construction 1649 01:02:48,200 --> 01:02:50,800 of every booster. 1650 01:02:50,800 --> 01:02:52,520 Another generation later, 1651 01:02:52,520 --> 01:02:53,520 building on the work of 1652 01:02:53,520 --> 01:02:56,560 Tsiolkovsky and Goddard, extending 1653 01:02:56,560 --> 01:02:58,320 Using von Braun's technological 1654 01:02:58,320 --> 01:03:00,760 genius, we were up there in 1655 01:03:00,760 --> 01:03:03,960 space, silently circumnavigating 1656 01:03:03,960 --> 01:03:06,920 the Earth, treading the 1657 01:03:06,920 --> 01:03:11,120 ancient and desolate lunar surface. 1658 01:03:11,120 --> 01:03:13,560 Our machines, increasingly 1659 01:03:13,560 --> 01:03:17,240 competent and autonomous, were 1660 01:03:17,240 --> 01:03:18,600 spreading through the solar 1661 01:03:18,600 --> 01:03:20,220 system, discovering 1662 01:03:20,220 --> 01:03:22,040 discovering new worlds, 1663 01:03:22,040 --> 01:03:23,680 examining them closely, 1664 01:03:23,680 --> 01:03:26,000 searching for life, comparing 1665 01:03:26,000 --> 01:03:29,960 them with Earth. 1666 01:03:29,960 --> 01:03:31,840 This is one reason that in 1667 01:03:31,840 --> 01:03:33,240 the long astronomical 1668 01:03:33,240 --> 01:03:35,440 perspective there is something 1669 01:03:35,440 --> 01:03:40,360 truly epical about now. 1670 01:03:40,360 --> 01:03:43,000 And there's a second reason. 1671 01:03:43,000 --> 01:03:44,240 This is the first moment in 1672 01:03:44,240 --> 01:03:46,080 the history of our planet 1673 01:03:46,080 --> 01:03:48,800 when any species by its own voluntary 1674 01:03:48,800 --> 01:03:52,560 actions has become a danger to itself. 1675 01:03:52,560 --> 01:03:54,440 We've been burning fossil fuels for 1676 01:03:54,440 --> 01:03:57,240 hundreds of thousands of years. 1677 01:03:57,240 --> 01:03:59,720 By the 1960s there were so 1678 01:03:59,720 --> 01:04:00,920 many of us burning 1679 01:04:00,920 --> 01:04:02,760 wood, coal, oil and natural 1680 01:04:02,760 --> 01:04:06,160 gas on so large a scale that 1681 01:04:06,160 --> 01:04:07,120 scientists began to 1682 01:04:07,120 --> 01:04:08,720 worry about the increasing 1683 01:04:08,720 --> 01:04:11,240 greenhouse effect. 1684 01:04:11,240 --> 01:04:13,800 The dangers of global warming 1685 01:04:13,800 --> 01:04:17,000 began slowly slipping into 1686 01:04:17,000 --> 01:04:19,000 public consciousness. 1687 01:04:19,000 --> 01:04:20,000 Nuclear weapons were 1688 01:04:20,000 --> 01:04:23,000 invented in 1945. 1689 01:04:23,000 --> 01:04:25,240 It took until 1983 before the 1690 01:04:25,240 --> 01:04:26,360 global consequences of 1691 01:04:26,360 --> 01:04:30,280 thermonuclear war were understood. 1692 01:04:30,280 --> 01:04:32,320 Biological warfare has been with us for 1693 01:04:32,320 --> 01:04:34,400 centuries, but it's deadly 1694 01:04:34,400 --> 01:04:37,000 mating with molecular biology 1695 01:04:37,000 --> 01:04:39,600 has occurred only lately. 1696 01:04:39,600 --> 01:04:41,000 We humans have already 1697 01:04:41,000 --> 01:04:42,720 precipitated extinctions of 1698 01:04:42,720 --> 01:04:44,160 species on a 1699 01:04:44,160 --> 01:04:45,760 scale unprecedented since the 1700 01:04:45,760 --> 01:04:48,520 end of the Cretaceous period, 1701 01:04:48,520 --> 01:04:49,440 but only in the last 1702 01:04:49,440 --> 01:04:51,120 decade has the magnitude of 1703 01:04:51,120 --> 01:04:54,000 these extinctions become clear and the 1704 01:04:54,000 --> 01:04:57,000 possibility raised that in our 1705 01:04:57,000 --> 01:04:59,280 ignorance of the interrelations 1706 01:04:59,280 --> 01:05:00,840 of life on Earth 1707 01:05:00,840 --> 01:05:05,520 we may be endangering our own future. 1708 01:05:05,520 --> 01:05:07,600 In the littered field of 1709 01:05:07,600 --> 01:05:09,920 discredited, self-congratulatory 1710 01:05:09,920 --> 01:05:12,720 chauvinisms, there is only one 1711 01:05:12,720 --> 01:05:13,080 that seems 1712 01:05:13,080 --> 01:05:15,120 to hold up, one sense in 1713 01:05:15,120 --> 01:05:19,200 which we are special, due to 1714 01:05:19,200 --> 01:05:22,160 our own actions or inactions, and the 1715 01:05:22,160 --> 01:05:24,440 misuse of our technology, we 1716 01:05:24,440 --> 01:05:25,920 live at an extraordinary 1717 01:05:25,920 --> 01:05:26,800 moment for the Earth, at 1718 01:05:26,800 --> 01:05:28,560 least the first 1719 01:05:28,560 --> 01:05:30,400 time that a species has been 1720 01:05:30,400 --> 01:05:33,720 able to wipe itself out. 1721 01:05:33,720 --> 01:05:36,600 But this is also, we may note, 1722 01:05:36,600 --> 01:05:38,040 the first time that a species 1723 01:05:38,040 --> 01:05:40,400 has become able to journey to 1724 01:05:40,400 --> 01:05:43,360 the planets and the stars. 1725 01:05:43,360 --> 01:05:45,800 The two times, brought about 1726 01:05:45,800 --> 01:05:49,880 by the same technology, coincide. 1727 01:05:49,880 --> 01:05:52,080 It might be a familiar progression, 1728 01:05:52,080 --> 01:05:55,080 Transpiring on many worlds, a 1729 01:05:55,080 --> 01:05:58,320 planet, newly formed, placidly 1730 01:05:58,320 --> 01:06:00,960 revolves around its star. 1731 01:06:00,960 --> 01:06:03,440 Life slowly forms. 1732 01:06:03,440 --> 01:06:05,240 A kaleidoscopic procession of 1733 01:06:05,240 --> 01:06:07,720 creatures evolves. 1734 01:06:07,720 --> 01:06:10,720 Intelligence emerges, which, at 1735 01:06:10,720 --> 01:06:13,440 least up to a point, confers 1736 01:06:13,440 --> 01:06:16,240 enormous survival value. 1737 01:06:16,240 --> 01:06:20,720 And then, technology is invented. 1738 01:06:20,720 --> 01:06:22,480 It dawns on them that there 1739 01:06:22,480 --> 01:06:23,880 are such things as laws of 1740 01:06:23,880 --> 01:06:26,400 nature, that these laws can be 1741 01:06:26,400 --> 01:06:28,960 revealed by experiment, and 1742 01:06:28,960 --> 01:06:31,480 that knowledge of these laws 1743 01:06:31,480 --> 01:06:33,840 can be made both to save and 1744 01:06:33,840 --> 01:06:36,160 to take lives, both on 1745 01:06:36,160 --> 01:06:38,440 unprecedented scales. 1746 01:06:38,440 --> 01:06:40,920 Science they recognize grants 1747 01:06:40,920 --> 01:06:43,280 immense powers. 1748 01:06:43,280 --> 01:06:45,760 In a flash, they create 1749 01:06:45,760 --> 01:06:48,920 world-altering contrivances. 1750 01:06:48,920 --> 01:06:50,640 Some planetary civilizations 1751 01:06:50,640 --> 01:06:52,760 see their way through, place 1752 01:06:52,760 --> 01:06:54,280 limits on what may and what 1753 01:06:54,280 --> 01:06:55,880 must not be done, 1754 01:06:55,880 --> 01:06:57,960 and safely pass through the 1755 01:06:57,960 --> 01:07:00,000 time of perils. 1756 01:07:00,000 --> 01:07:03,120 Others, not so lucky or so 1757 01:07:03,120 --> 01:07:06,520 prudent, perish. 1758 01:07:06,520 --> 01:07:08,640 Since, in the long run, every 1759 01:07:08,640 --> 01:07:09,920 planetary society will be 1760 01:07:09,920 --> 01:07:13,000 endangered by impacts from space, 1761 01:07:13,000 --> 01:07:15,120 Every surviving civilization is 1762 01:07:15,120 --> 01:07:18,000 obliged to become spacefaring. 1763 01:07:18,000 --> 01:07:20,320 Not because of exploratory or 1764 01:07:20,320 --> 01:07:22,320 romantic zeal, 1765 01:07:22,320 --> 01:07:24,000 but for the most practical 1766 01:07:24,000 --> 01:07:25,520 reason imaginable. 1767 01:07:26,360 --> 01:07:29,000 Staying alive. 1768 01:07:29,000 --> 01:07:30,160 And once you're out there in 1769 01:07:30,160 --> 01:07:32,440 space for centuries, 1770 01:07:32,440 --> 01:07:34,360 for millennia, 1771 01:07:34,360 --> 01:07:37,080 moving little worlds around, 1772 01:07:37,080 --> 01:07:39,400 engineering planets, 1773 01:07:39,400 --> 01:07:41,200 Your species has been pried 1774 01:07:41,200 --> 01:07:44,560 loose from its cradle. 1775 01:07:44,560 --> 01:07:47,000 If they exist, many other 1776 01:07:47,000 --> 01:07:49,880 civilizations will eventually 1777 01:07:49,880 --> 01:07:53,600 venture far from home. 1778 01:07:53,600 --> 01:07:54,840 Of course we must keep our 1779 01:07:54,840 --> 01:07:57,040 planet habitable, not on a 1780 01:07:57,040 --> 01:07:59,120 leisurely timescale of centuries 1781 01:07:59,120 --> 01:08:01,120 or millennia, but urgently on 1782 01:08:01,120 --> 01:08:04,640 a timescale of decades or even years. 1783 01:08:04,640 --> 01:08:06,280 This will involve changes in 1784 01:08:06,280 --> 01:08:09,160 government, in industry, in 1785 01:08:09,160 --> 01:08:12,960 ethics, in economics and in religion. 1786 01:08:12,960 --> 01:08:14,200 We've never done such a thing 1787 01:08:14,200 --> 01:08:16,000 before, certainly not on a 1788 01:08:16,000 --> 01:08:17,920 global scale. 1789 01:08:17,920 --> 01:08:20,400 It may well be too difficult for us. 1790 01:08:20,400 --> 01:08:22,480 Dangerous technologies may be 1791 01:08:22,480 --> 01:08:24,280 too widespread. 1792 01:08:24,280 --> 01:08:27,000 Corruption may be too pervasive. 1793 01:08:27,000 --> 01:08:28,200 Too many leaders may be 1794 01:08:28,200 --> 01:08:29,960 focused on the short term 1795 01:08:29,960 --> 01:08:32,000 rather than the long. 1796 01:08:32,000 --> 01:08:32,800 There may be too many 1797 01:08:32,800 --> 01:08:34,600 quarreling ethnic groups, 1798 01:08:34,600 --> 01:08:37,280 nation-states, and ideologies 1799 01:08:37,280 --> 01:08:37,960 for the right 1800 01:08:37,960 --> 01:08:40,920 kind of global change to be instituted. 1801 01:08:40,920 --> 01:08:42,240 We may be too foolish to 1802 01:08:42,240 --> 01:08:44,120 perceive even what the real 1803 01:08:44,120 --> 01:08:46,440 dangers are, or that much of what 1804 01:08:46,440 --> 01:08:47,960 we hear about them is 1805 01:08:47,960 --> 01:08:49,240 determined by those with a 1806 01:08:49,240 --> 01:08:51,160 vested interest in minimizing 1807 01:08:51,160 --> 01:08:53,640 fundamental change. 1808 01:08:53,640 --> 01:08:55,040 However, we humans also have 1809 01:08:55,040 --> 01:08:56,600 a history of making 1810 01:08:56,600 --> 01:08:59,160 long-lasting social change that nearly 1811 01:08:59,160 --> 01:09:02,480 everyone thought was impossible. 1812 01:09:02,480 --> 01:09:04,640 Since our earliest days, we've 1813 01:09:04,640 --> 01:09:06,520 worked not just for our 1814 01:09:06,520 --> 01:09:08,600 own advantage, but for our 1815 01:09:08,600 --> 01:09:11,760 children and our grandchildren. 1816 01:09:11,760 --> 01:09:13,440 The newly recognized dangers 1817 01:09:13,440 --> 01:09:17,120 threaten all of us equally. 1818 01:09:17,120 --> 01:09:19,280 No one can say how it will 1819 01:09:19,280 --> 01:09:22,000 turn out down here. 1820 01:09:22,000 --> 01:09:24,040 The moon was where the tree 1821 01:09:24,040 --> 01:09:26,560 of immortality grew in ancient 1822 01:09:26,560 --> 01:09:28,880 Chinese myth. 1823 01:09:28,880 --> 01:09:32,400 The tree of longevity indeed 1824 01:09:32,400 --> 01:09:35,120 grows on other worlds. 1825 01:09:35,120 --> 01:09:36,560 If we were up there among 1826 01:09:36,560 --> 01:09:38,800 the planets, if there were 1827 01:09:38,800 --> 01:09:40,080 self-sufficient human 1828 01:09:40,080 --> 01:09:41,000 communities on many 1829 01:09:41,000 --> 01:09:43,480 worlds, our species would be 1830 01:09:43,480 --> 01:09:46,440 insulated from catastrophe. 1831 01:09:46,440 --> 01:09:47,800 A cataclysmic impact on 1832 01:09:47,800 --> 01:09:49,840 one world would likely leave 1833 01:09:49,840 --> 01:09:52,840 the others untouched. 1834 01:09:52,840 --> 01:09:54,120 The more of us beyond the 1835 01:09:54,120 --> 01:09:55,800 Earth, the greater the 1836 01:09:55,800 --> 01:09:56,920 diversity of worlds we 1837 01:09:56,920 --> 01:09:59,160 inhabit, the more varied the 1838 01:09:59,160 --> 01:10:01,400 planetary engineering, the 1839 01:10:01,400 --> 01:10:02,920 greater the range of societal 1840 01:10:02,920 --> 01:10:05,320 standards and values, 1841 01:10:05,320 --> 01:10:06,920 then the safer the human 1842 01:10:06,920 --> 01:10:09,000 species will be. 1843 01:10:09,000 --> 01:10:12,720 This strategy, breaking up into many 1844 01:10:12,720 --> 01:10:15,600 smaller self-propagating groups, 1845 01:10:15,600 --> 01:10:16,760 each with somewhat different 1846 01:10:16,760 --> 01:10:17,520 strengths and 1847 01:10:17,520 --> 01:10:19,720 concerns but all marked by 1848 01:10:19,720 --> 01:10:22,400 local pride has been widely 1849 01:10:22,400 --> 01:10:23,040 employed in the 1850 01:10:23,040 --> 01:10:25,040 evolution of life on Earth 1851 01:10:25,040 --> 01:10:28,920 and by our own ancestors in particular. 1852 01:10:28,920 --> 01:10:29,560 It may in 1853 01:10:29,560 --> 01:10:31,560 fact be key to understanding 1854 01:10:31,560 --> 01:10:35,360 why we humans are the way we are. 1855 01:10:35,360 --> 01:10:36,020 If our long 1856 01:10:36,020 --> 01:10:38,520 term survival is at stake we 1857 01:10:38,520 --> 01:10:40,720 have a basic responsibility to 1858 01:10:40,720 --> 01:10:42,600 our species to 1859 01:10:42,600 --> 01:10:46,040 venture to other worlds. 1860 01:10:46,040 --> 01:10:51,240 Sailors on a becalmed sea, we 1861 01:10:51,240 --> 01:10:55,240 sense the stirring of a breeze. 1862 01:11:21,800 --> 01:11:25,480 As children, we fear the dark. 1863 01:11:25,480 --> 01:11:27,680 Anything might be out there. 1864 01:11:27,680 --> 01:11:33,320 The unknown troubles us. Ironically, 1865 01:11:33,320 --> 01:11:36,400 Maybe it's our fate to live 1866 01:11:36,400 --> 01:11:38,840 in the dark. 1867 01:11:38,840 --> 01:11:40,600 This unexpected finding of 1868 01:11:40,600 --> 01:11:41,760 science is only about three 1869 01:11:41,760 --> 01:11:43,920 centuries old. 1870 01:11:43,920 --> 01:11:45,000 Head out from the Earth in 1871 01:11:45,000 --> 01:11:49,000 any direction you choose, and 1872 01:11:49,000 --> 01:11:51,440 after an initial flash of blue 1873 01:11:51,440 --> 01:11:52,760 and a longer wait while the 1874 01:11:52,760 --> 01:11:55,520 Sun fades, you are surrounded 1875 01:11:55,520 --> 01:11:58,440 by blackness, punctuated only 1876 01:11:58,440 --> 01:12:01,080 here and there by the faint 1877 01:12:01,080 --> 01:12:04,800 and distant stars. 1878 01:12:04,800 --> 01:12:07,160 Even after we're grown, the 1879 01:12:07,160 --> 01:12:08,920 darkness retains its power to 1880 01:12:08,920 --> 01:12:11,040 frighten us. 1881 01:12:11,040 --> 01:12:12,200 And so there are those who 1882 01:12:12,200 --> 01:12:14,960 say we should not inquire too closely 1883 01:12:14,960 --> 01:12:16,880 into who else might be living 1884 01:12:16,880 --> 01:12:19,200 in that darkness. 1885 01:12:19,200 --> 01:12:24,880 Better not to know, they say. 1886 01:12:24,880 --> 01:12:27,800 There are 400 billion stars 1887 01:12:27,800 --> 01:12:30,320 in the Milky Way galaxy. 1888 01:12:30,320 --> 01:12:32,480 Of this immense multitude, 1889 01:12:32,480 --> 01:12:35,320 could it be that our humdrum sun 1890 01:12:35,320 --> 01:12:37,000 is the only one with an 1891 01:12:37,000 --> 01:12:39,600 inhabited planet? 1892 01:12:39,600 --> 01:12:43,880 Maybe. Maybe the origin of life, or 1893 01:12:43,880 --> 01:12:45,720 intelligence, is 1894 01:12:45,720 --> 01:12:48,360 exceedingly improbable. 1895 01:12:48,360 --> 01:12:53,080 Or, maybe, civilizations arise all the 1896 01:12:53,080 --> 01:12:56,120 time, but wipe themselves out 1897 01:12:56,120 --> 01:12:59,240 as soon as they are able. 1898 01:12:59,240 --> 01:13:02,880 Or, here and there, peppered 1899 01:13:02,880 --> 01:13:05,920 across space, orbiting other 1900 01:13:05,920 --> 01:13:10,120 suns, maybe there are worlds 1901 01:13:10,120 --> 01:13:13,160 something like our own, on which 1902 01:13:13,160 --> 01:13:15,240 other beings gaze up and 1903 01:13:15,240 --> 01:13:17,400 wonder as we do about who 1904 01:13:17,400 --> 01:13:20,920 else lives in the dark. 1905 01:13:20,920 --> 01:13:22,080 Could the Milky Way be 1906 01:13:22,080 --> 01:13:24,000 rippling with life and 1907 01:13:24,000 --> 01:13:26,320 intelligence, worlds calling 1908 01:13:26,320 --> 01:13:27,960 out to worlds, 1909 01:13:27,960 --> 01:13:29,680 while we on Earth are alive 1910 01:13:29,680 --> 01:13:31,640 at the critical moment when 1911 01:13:31,640 --> 01:13:32,840 we first decide to 1912 01:13:32,840 --> 01:13:38,520 listen, our species has 1913 01:13:38,520 --> 01:13:39,240 discovered a way to 1914 01:13:39,240 --> 01:13:42,160 communicate through the dark, to 1915 01:13:42,160 --> 01:13:45,800 transcend immense distances. 1916 01:13:45,800 --> 01:13:47,760 No means of communication is 1917 01:13:47,760 --> 01:13:50,560 faster or cheaper or 1918 01:13:50,560 --> 01:13:55,040 reaches out farther. It's called radio. 1919 01:13:57,960 --> 01:13:59,640 After billions of years of biological 1920 01:13:59,640 --> 01:14:01,920 evolution on their planet and 1921 01:14:01,920 --> 01:14:04,880 ours, an alien civilization 1922 01:14:04,880 --> 01:14:05,760 cannot be in 1923 01:14:05,760 --> 01:14:09,560 technological lockstep with us. 1924 01:14:09,560 --> 01:14:10,600 There have been humans for 1925 01:14:10,600 --> 01:14:11,920 more than 20,000 1926 01:14:11,920 --> 01:14:15,280 centuries, but we've had radio 1927 01:14:15,280 --> 01:14:18,720 only for about one century. If alien 1928 01:14:18,720 --> 01:14:20,760 civilizations are behind us, 1929 01:14:20,760 --> 01:14:21,960 they're likely to be too far 1930 01:14:21,960 --> 01:14:24,640 behind to have radio. 1931 01:14:24,640 --> 01:14:26,440 And if they're ahead of us, 1932 01:14:26,440 --> 01:14:30,760 they're likely to be far ahead of us. 1933 01:14:30,760 --> 01:14:31,160 Think of 1934 01:14:31,160 --> 01:14:32,600 the technical advances in our 1935 01:14:32,600 --> 01:14:36,720 world over just the last few centuries. 1936 01:14:36,720 --> 01:14:37,600 What is for 1937 01:14:37,600 --> 01:14:39,520 us technologically difficult 1938 01:14:39,520 --> 01:14:42,240 or impossible? 1939 01:14:42,240 --> 01:14:43,840 What might seem to us like 1940 01:14:43,840 --> 01:14:48,760 magic might for them be trivially easy. 1941 01:14:48,760 --> 01:14:50,800 They might use other very 1942 01:14:50,800 --> 01:14:51,560 advanced means 1943 01:14:51,560 --> 01:14:52,680 to communicate with their 1944 01:14:52,680 --> 01:14:54,720 peers, but they would know 1945 01:14:54,720 --> 01:14:57,040 about radio as an approach to 1946 01:14:57,040 --> 01:15:00,480 newly emerging civilizations. 1947 01:15:00,480 --> 01:15:01,680 Even with no more than our 1948 01:15:01,680 --> 01:15:03,160 level of technology at the 1949 01:15:03,160 --> 01:15:05,920 transmitting and receiving ends, we 1950 01:15:05,920 --> 01:15:08,360 could communicate today across 1951 01:15:08,360 --> 01:15:10,680 much of the galaxy. 1952 01:15:10,680 --> 01:15:14,200 They should be able to do much better. 1953 01:15:14,200 --> 01:15:19,000 If they exist. 1954 01:15:19,000 --> 01:15:22,040 But our fear of the dark rebels. 1955 01:15:22,040 --> 01:15:24,960 The idea of alien beings troubles us. 1956 01:15:25,680 --> 01:15:28,920 We conjure up objections. 1957 01:15:28,920 --> 01:15:32,680 It's too expensive, some of us say. 1958 01:15:32,680 --> 01:15:34,720 But in its fullest modern 1959 01:15:34,720 --> 01:15:36,720 technological expression, 1960 01:15:36,720 --> 01:15:38,720 it costs less than one attack 1961 01:15:38,720 --> 01:15:41,920 helicopter a year. 1962 01:15:41,920 --> 01:15:42,960 We'll never understand what 1963 01:15:42,960 --> 01:15:43,960 they're saying, 1964 01:15:43,960 --> 01:15:46,600 some of us say. 1965 01:15:46,600 --> 01:15:47,720 But because the message is 1966 01:15:47,720 --> 01:15:51,520 transmitted by radio, we and they must 1967 01:15:51,520 --> 01:15:54,200 have radio physics, radio 1968 01:15:54,200 --> 01:15:57,000 astronomy, and radio technology 1969 01:15:57,000 --> 01:15:58,440 in common. 1970 01:15:58,440 --> 01:15:59,000 The laws of 1971 01:15:59,000 --> 01:16:00,840 nature are the same 1972 01:16:00,840 --> 01:16:03,320 everywhere, so science itself 1973 01:16:03,320 --> 01:16:04,880 provides a means and 1974 01:16:04,880 --> 01:16:07,160 language of communication, even 1975 01:16:07,160 --> 01:16:08,560 between very different kinds 1976 01:16:08,560 --> 01:16:11,000 of beings, provided 1977 01:16:11,000 --> 01:16:13,360 they both have science. 1978 01:16:13,360 --> 01:16:15,360 Figuring out the message, if 1979 01:16:15,360 --> 01:16:16,680 we're fortunate enough to 1980 01:16:16,680 --> 01:16:19,160 receive one, may be much 1981 01:16:19,160 --> 01:16:23,720 easier than acquiring it. 1982 01:16:23,720 --> 01:16:25,720 It would be demoralizing 1983 01:16:25,720 --> 01:16:27,240 to learn that our science is 1984 01:16:27,240 --> 01:16:30,640 primitive, some say. 1985 01:16:30,640 --> 01:16:31,720 But by the standards of the 1986 01:16:31,720 --> 01:16:33,680 next few centuries, at least 1987 01:16:33,680 --> 01:16:34,920 some of our present science 1988 01:16:34,920 --> 01:16:35,640 will be considered 1989 01:16:35,640 --> 01:16:37,360 primitive, extraterrestrials or 1990 01:16:37,360 --> 01:16:39,920 no extraterrestrials. 1991 01:16:39,920 --> 01:16:40,880 Incidentally, so will 1992 01:16:40,880 --> 01:16:42,640 some of our present politics, 1993 01:16:42,640 --> 01:16:46,200 ethics, economics, and religion. 1994 01:16:46,200 --> 01:16:48,520 To go beyond present science 1995 01:16:48,520 --> 01:16:52,400 is one of the chief goals of science. 1996 01:16:52,400 --> 01:16:55,840 The debate is, for the moment, moot. 1997 01:16:56,680 --> 01:17:00,440 We are now on an unprecedented scale, 1998 01:17:00,440 --> 01:17:02,200 listening for radio signals 1999 01:17:02,200 --> 01:17:04,400 from possible other civilizations 2000 01:17:04,400 --> 01:17:07,040 in the depths of space. 2001 01:17:07,040 --> 01:17:08,920 Alive today 2002 01:17:08,920 --> 01:17:11,320 is the first generation of scientists 2003 01:17:11,320 --> 01:17:14,360 to interrogate the darkness. 2004 01:17:14,360 --> 01:17:16,880 Conceivably, it might also be 2005 01:17:16,880 --> 01:17:18,400 the last generation 2006 01:17:18,400 --> 01:17:21,200 before contact is made. 2007 01:17:21,200 --> 01:17:24,000 And this the last moment 2008 01:17:24,000 --> 01:17:26,200 before we discover that someone 2009 01:17:26,200 --> 01:17:31,120 in the darkness is calling out to us. 2010 01:17:31,120 --> 01:17:33,320 Let's permit ourselves though a moment 2011 01:17:33,320 --> 01:17:36,960 of extravagant speculation. 2012 01:17:36,960 --> 01:17:39,480 Then we can estimate from how 2013 01:17:39,480 --> 01:17:40,160 little time we've 2014 01:17:40,160 --> 01:17:41,800 spent watching each piece of 2015 01:17:41,800 --> 01:17:44,240 the sky, how many such 2016 01:17:44,240 --> 01:17:45,760 transmitters there are in the 2017 01:17:45,760 --> 01:17:47,680 entire Milky Way? 2018 01:17:47,680 --> 01:17:50,120 The answer is something 2019 01:17:50,120 --> 01:17:53,200 approaching a million. 2020 01:17:53,200 --> 01:17:54,840 If randomly strewn through space, 2021 01:17:55,760 --> 01:17:57,360 the nearest of them would be 2022 01:17:57,360 --> 01:17:59,640 a few hundred light years away. 2023 01:17:59,640 --> 01:18:01,560 Too far for them to have 2024 01:18:01,560 --> 01:18:03,600 picked up our own TV or 2025 01:18:03,600 --> 01:18:07,280 radar signals yet. 2026 01:18:07,280 --> 01:18:08,920 They would not know for 2027 01:18:08,920 --> 01:18:10,520 another few centuries 2028 01:18:10,520 --> 01:18:12,480 that a technical civilization 2029 01:18:12,480 --> 01:18:14,520 had emerged on Earth. 2030 01:18:14,520 --> 01:18:16,240 The galaxy would be pulsing 2031 01:18:16,240 --> 01:18:18,800 with life and intelligence, 2032 01:18:18,800 --> 01:18:20,400 but unless they're busily 2033 01:18:20,400 --> 01:18:22,120 exploring huge numbers of 2034 01:18:22,120 --> 01:18:23,840 obscure star systems, 2035 01:18:23,840 --> 01:18:26,000 they'd be wholly oblivious of 2036 01:18:26,000 --> 01:18:29,640 what's been happening down here lately. 2037 01:18:29,640 --> 01:18:31,640 A few centuries from now, 2038 01:18:31,640 --> 01:18:33,760 after they do hear from us, 2039 01:18:33,760 --> 01:18:39,800 things might get very interesting. 2040 01:18:39,800 --> 01:18:41,200 Elsewhere, there may be 2041 01:18:41,200 --> 01:18:42,760 engineering on a scale that 2042 01:18:42,760 --> 01:18:47,400 dwarfs our proudest achievements. 2043 01:18:47,400 --> 01:18:49,120 Imagine the energy crisis of 2044 01:18:49,120 --> 01:18:50,400 a really advanced 2045 01:18:50,400 --> 01:18:52,520 planetary civilization. 2046 01:18:52,520 --> 01:18:53,600 They've used up all their 2047 01:18:53,600 --> 01:18:55,840 fuels, they depend on solar 2048 01:18:55,840 --> 01:18:58,080 power, but their growth is still 2049 01:18:58,080 --> 01:18:59,280 severely limited by the 2050 01:18:59,280 --> 01:19:00,720 energy available. 2051 01:19:00,720 --> 01:19:02,000 An enormous amount of energy 2052 01:19:02,000 --> 01:19:03,240 is generated by the local 2053 01:19:03,240 --> 01:19:05,400 star, but most of the star's 2054 01:19:05,400 --> 01:19:08,200 light doesn't fall on their planet. 2055 01:19:08,200 --> 01:19:10,320 So perhaps they would build a 2056 01:19:10,320 --> 01:19:13,560 shell to surround their star 2057 01:19:13,560 --> 01:19:18,800 and harvest every photon of sunlight. 2058 01:19:18,800 --> 01:19:21,720 Such beings, such civilizations 2059 01:19:21,720 --> 01:19:23,440 would bear little resemblance 2060 01:19:23,440 --> 01:19:24,720 to anything we know. 2061 01:19:33,040 --> 01:19:35,600 Perhaps someday there will be 2062 01:19:35,600 --> 01:19:37,080 an entry in the Encyclopedia 2063 01:19:37,080 --> 01:19:40,040 Galactica for our planet. 2064 01:19:40,040 --> 01:19:41,600 Or perhaps even now there 2065 01:19:41,600 --> 01:19:43,880 exists somewhere a planetary 2066 01:19:43,880 --> 01:19:46,400 dossier garnered from our television 2067 01:19:46,400 --> 01:19:48,200 broadcasts or from some 2068 01:19:48,200 --> 01:19:50,720 discrete survey mission. 2069 01:19:50,720 --> 01:19:51,760 They might summon up the 2070 01:19:51,760 --> 01:19:53,240 index of blue worlds 2071 01:19:53,240 --> 01:19:54,800 in our province of the Milky 2072 01:19:54,800 --> 01:19:56,400 Way until they came to the 2073 01:19:56,400 --> 01:19:58,880 listing for Earth. What would 2074 01:19:58,880 --> 01:20:01,320 they know about us? 2075 01:20:01,320 --> 01:20:06,480 What would they think of us? 2076 01:20:06,480 --> 01:20:09,280 We have always watched the stars and 2077 01:20:09,280 --> 01:20:11,440 mused about whether there are 2078 01:20:11,440 --> 01:20:13,600 other beings who think and 2079 01:20:13,600 --> 01:20:19,440 wonder in a cosmic setting vast 2080 01:20:19,440 --> 01:20:20,920 and old, beyond ordinary 2081 01:20:20,920 --> 01:20:22,760 human understanding. 2082 01:20:22,760 --> 01:20:24,640 We are a little lonely. 2083 01:20:26,000 --> 01:20:27,680 In the deepest sense, 2084 01:20:27,680 --> 01:20:29,320 the search for extraterrestrial 2085 01:20:29,320 --> 01:20:32,000 intelligence is a search. 2086 01:21:16,240 --> 01:21:18,360 The spacecraft was a long way 2087 01:21:18,360 --> 01:21:20,600 from home, beyond the orbit 2088 01:21:20,600 --> 01:21:22,360 of the outermost planet and high above 2089 01:21:22,360 --> 01:21:24,600 the ecliptic plane. 2090 01:21:24,600 --> 01:21:25,760 The ship was speeding away 2091 01:21:25,760 --> 01:21:29,240 from the Sun at 40,000 miles an hour. 2092 01:21:29,240 --> 01:21:31,080 But in early February of 2093 01:21:31,080 --> 01:21:33,560 1990, it was overtaken by an 2094 01:21:33,560 --> 01:21:36,840 urgent message from Earth. 2095 01:21:36,840 --> 01:21:38,640 Obediently, it turned its cameras 2096 01:21:38,640 --> 01:21:40,440 back toward the now distant 2097 01:21:40,440 --> 01:21:42,400 planets, slewing 2098 01:21:42,400 --> 01:21:44,440 its scan platform from one spot in 2099 01:21:44,440 --> 01:21:46,600 the sky to another. 2100 01:21:46,600 --> 01:21:48,880 It snapped 60 pictures 2101 01:21:48,880 --> 01:21:50,800 and stored them in digital form 2102 01:21:50,800 --> 01:21:53,120 on its tape recorder. 2103 01:21:53,120 --> 01:21:54,640 Then, slowly, in 2104 01:21:54,640 --> 01:21:56,800 March, April, and May, 2105 01:21:56,800 --> 01:21:59,240 it radioed the data back to Earth. 2106 01:21:59,240 --> 01:22:00,880 The spacecraft was 3.7 2107 01:22:00,880 --> 01:22:02,920 billion miles away from Earth, 2108 01:22:02,920 --> 01:22:05,000 so far away that it took 2109 01:22:05,000 --> 01:22:07,440 each pixel five and a half hours 2110 01:22:07,440 --> 01:22:08,480 traveling at the speed of 2111 01:22:08,480 --> 01:22:10,840 light to reach us. 2112 01:22:10,840 --> 01:22:12,440 The two Voyager robots have 2113 01:22:12,440 --> 01:22:14,760 explored four planets 2114 01:22:14,760 --> 01:22:18,040 and nearly 60 moons. 2115 01:22:18,040 --> 01:22:20,920 They are triumphs of human engineering 2116 01:22:20,920 --> 01:22:22,080 and one of the glories of 2117 01:22:22,080 --> 01:22:24,520 the American space program. 2118 01:22:24,520 --> 01:22:26,240 They will be in the history books 2119 01:22:26,240 --> 01:22:28,080 when much else about our time 2120 01:22:28,080 --> 01:22:30,520 is forgotten. 2121 01:22:30,520 --> 01:22:31,720 The Voyagers were guaranteed 2122 01:22:31,720 --> 01:22:33,200 to work only until the 2123 01:22:33,200 --> 01:22:34,760 Saturn encounter. 2124 01:22:34,760 --> 01:22:35,680 I thought it might be a good 2125 01:22:35,680 --> 01:22:37,480 idea, just after Saturn, to 2126 01:22:37,480 --> 01:22:38,640 have them take one last 2127 01:22:38,640 --> 01:22:40,480 glance homeward. 2128 01:22:40,480 --> 01:22:42,320 From Saturn, I knew, the 2129 01:22:42,320 --> 01:22:43,520 Earth would appear too small 2130 01:22:43,520 --> 01:22:46,080 for Voyager to make out any detail. 2131 01:22:46,080 --> 01:22:47,800 Our planet would be just a 2132 01:22:47,800 --> 01:22:50,560 point of light, a lonely pixel. 2133 01:22:50,560 --> 01:22:51,880 Hardly distinguishable from the 2134 01:22:51,880 --> 01:22:53,440 many other points of light 2135 01:22:53,440 --> 01:22:54,440 Voyager would see, 2136 01:22:55,080 --> 01:22:58,720 nearby planets, far-off suns. 2137 01:22:58,720 --> 01:23:00,520 But precisely because of the 2138 01:23:00,520 --> 01:23:02,080 obscurity of our world thus 2139 01:23:02,080 --> 01:23:04,200 revealed, such a picture might 2140 01:23:04,200 --> 01:23:07,080 be worth having. 2141 01:23:07,080 --> 01:23:08,960 Mariners had painstakingly 2142 01:23:08,960 --> 01:23:10,280 mapped the coastlines of 2143 01:23:10,280 --> 01:23:11,960 the continents. 2144 01:23:11,960 --> 01:23:13,560 Geographers had translated 2145 01:23:13,560 --> 01:23:16,960 these findings into charts and globes. 2146 01:23:16,960 --> 01:23:19,200 Photographs of tiny patches of 2147 01:23:19,200 --> 01:23:21,080 the Earth had been obtained 2148 01:23:21,080 --> 01:23:24,120 first by balloons and aircraft, 2149 01:23:24,120 --> 01:23:25,920 then by rockets in brief 2150 01:23:25,920 --> 01:23:28,360 ballistic flight, and at last 2151 01:23:28,360 --> 01:23:30,800 by orbiting spacecraft, giving 2152 01:23:30,800 --> 01:23:32,000 a perspective like the one 2153 01:23:32,000 --> 01:23:34,000 you achieve by positioning 2154 01:23:34,000 --> 01:23:35,640 your eyeball about an inch above 2155 01:23:35,640 --> 01:23:37,880 a large globe. 2156 01:23:37,880 --> 01:23:38,880 While almost everyone has 2157 01:23:38,880 --> 01:23:39,840 taught that the Earth is a 2158 01:23:39,840 --> 01:23:42,160 sphere, with all of us somehow 2159 01:23:42,160 --> 01:23:44,960 glued to it by gravity, the 2160 01:23:44,960 --> 01:23:46,600 reality of our circumstance 2161 01:23:46,600 --> 01:23:48,200 did not really begin to sink 2162 01:23:48,200 --> 01:23:50,960 begin, until the famous 2163 01:23:50,960 --> 01:23:53,560 frame-filling Apollo photograph 2164 01:23:53,560 --> 01:23:55,760 of the whole Earth, the one taken 2165 01:23:55,760 --> 01:23:57,760 by the Apollo 17 astronauts 2166 01:23:57,760 --> 01:23:59,600 on the last journey of humans 2167 01:23:59,600 --> 01:24:01,600 to the Moon. 2168 01:24:01,600 --> 01:24:03,800 It has become a kind of icon 2169 01:24:03,800 --> 01:24:05,880 of our age. 2170 01:24:05,880 --> 01:24:06,960 You can make out the blue of 2171 01:24:06,960 --> 01:24:09,080 the ocean, the yellow-red of 2172 01:24:09,080 --> 01:24:12,000 the Sahara and the Arabian desert, 2173 01:24:12,000 --> 01:24:14,160 the brown-green of forest 2174 01:24:14,160 --> 01:24:16,040 and grassland. 2175 01:24:16,040 --> 01:24:17,640 And yet, there is no sign of 2176 01:24:17,640 --> 01:24:19,400 humans in this picture. 2177 01:24:19,400 --> 01:24:20,920 Not our reworking of the 2178 01:24:20,920 --> 01:24:23,000 Earth's surface, not our 2179 01:24:23,000 --> 01:24:26,040 machines, not ourselves. 2180 01:24:26,040 --> 01:24:28,120 We are too small, and our 2181 01:24:28,120 --> 01:24:30,280 statecraft is too feeble to 2182 01:24:30,280 --> 01:24:32,680 be seen by a spacecraft between 2183 01:24:32,680 --> 01:24:35,240 the Earth and the Moon. 2184 01:24:35,240 --> 01:24:37,520 From this vantage point, our 2185 01:24:37,520 --> 01:24:39,320 obsession with nationalism is 2186 01:24:39,320 --> 01:24:41,440 nowhere in evidence. 2187 01:24:41,440 --> 01:24:42,680 The Apollo pictures of the 2188 01:24:42,680 --> 01:24:44,400 whole Earth, conveyed to 2189 01:24:44,400 --> 01:24:46,400 multitudes, something well 2190 01:24:46,400 --> 01:24:48,400 known to astronomers, 2191 01:24:48,400 --> 01:24:50,720 on the scale of worlds, to 2192 01:24:50,720 --> 01:24:52,080 say nothing of stars or 2193 01:24:52,080 --> 01:24:56,440 galaxies, humans are inconsequential, 2194 01:24:56,440 --> 01:24:59,280 a thin film of life on an 2195 01:24:59,280 --> 01:25:02,720 obscure and solitary lump of 2196 01:25:02,720 --> 01:25:05,000 rock and metal. 2197 01:25:05,000 --> 01:25:06,160 It seemed to me that another 2198 01:25:06,160 --> 01:25:07,440 picture of the Earth, this 2199 01:25:07,440 --> 01:25:09,720 one taken from a hundred thousand 2200 01:25:09,720 --> 01:25:12,320 times farther away, might help 2201 01:25:12,320 --> 01:25:14,040 in the continuing process of 2202 01:25:14,040 --> 01:25:16,440 revealing to ourselves our true 2203 01:25:16,440 --> 01:25:19,920 circumstance and condition. 2204 01:25:19,920 --> 01:25:21,000 It had been well understood 2205 01:25:21,000 --> 01:25:22,120 by the scientists and 2206 01:25:22,120 --> 01:25:23,480 philosophers of classical 2207 01:25:23,480 --> 01:25:24,800 antiquity that 2208 01:25:24,800 --> 01:25:26,960 the Earth was a mere point 2209 01:25:26,960 --> 01:25:30,960 in a vast, encompassing cosmos. 2210 01:25:30,960 --> 01:25:33,680 But no one had ever seen it as such. 2211 01:25:33,680 --> 01:25:35,640 Here was our first chance, 2212 01:25:35,640 --> 01:25:37,360 and perhaps also our last, 2213 01:25:37,360 --> 01:25:40,080 for decades to come. 2214 01:25:40,080 --> 01:25:43,720 At last, the time came. 2215 01:25:43,720 --> 01:25:45,880 A mosaic of squares laid down 2216 01:25:45,880 --> 01:25:47,480 on top of the planets 2217 01:25:47,480 --> 01:25:49,640 and a background smattering of 2218 01:25:49,640 --> 01:25:51,800 more distant stars. 2219 01:25:51,800 --> 01:25:53,120 We were able to photograph 2220 01:25:53,120 --> 01:25:54,240 not only the Earth 2221 01:25:54,760 --> 01:25:56,800 but also five other of the 2222 01:25:56,800 --> 01:25:59,440 Sun's nine known planets. 2223 01:25:59,440 --> 01:26:00,520 This is how the planets would 2224 01:26:00,520 --> 01:26:02,400 look to an alien spaceship 2225 01:26:02,400 --> 01:26:04,280 approaching the solar system 2226 01:26:04,280 --> 01:26:08,000 after a long interstellar voyage. 2227 01:26:08,000 --> 01:26:09,080 From this distance, the 2228 01:26:09,080 --> 01:26:10,600 planets seem only points of 2229 01:26:10,600 --> 01:26:13,840 light, smeared or unsmeared, even 2230 01:26:13,840 --> 01:26:14,840 through the high-resolution 2231 01:26:14,840 --> 01:26:17,720 telescope aboard Voyager. 2232 01:26:17,720 --> 01:26:19,000 They are like the planets seen with 2233 01:26:19,000 --> 01:26:19,880 the naked eye from the 2234 01:26:19,880 --> 01:26:22,520 surface of the Earth, luminous 2235 01:26:22,520 --> 01:26:26,080 dots, brighter than most of the stars. 2236 01:26:26,080 --> 01:26:27,280 You cannot tell merely by 2237 01:26:27,280 --> 01:26:28,520 looking at one of these dots 2238 01:26:28,520 --> 01:26:30,720 what it's like, what's on it, 2239 01:26:30,720 --> 01:26:32,840 what its past has been, and 2240 01:26:32,840 --> 01:26:34,240 whether, in this particular 2241 01:26:34,240 --> 01:26:37,800 epoch, anyone lives there. 2242 01:26:37,800 --> 01:26:38,840 Because of the reflection of 2243 01:26:38,840 --> 01:26:40,040 sunlight off the spacecraft, 2244 01:26:40,040 --> 01:26:41,760 the Earth seems to be sitting 2245 01:26:41,760 --> 01:26:43,640 in a beam of light, 2246 01:26:43,640 --> 01:26:45,160 as if there were some special 2247 01:26:45,160 --> 01:26:48,160 significance to this small world. 2248 01:26:48,160 --> 01:26:49,600 But it's just an accident of 2249 01:26:49,600 --> 01:26:52,320 geometry and optics. 2250 01:26:52,320 --> 01:26:54,280 The Sun emits its radiation 2251 01:26:54,280 --> 01:26:56,840 equitably in all directions. 2252 01:26:56,840 --> 01:26:58,000 Had the picture been taken a 2253 01:26:58,000 --> 01:27:00,840 little earlier, or a little later, 2254 01:27:00,840 --> 01:27:01,600 there would have been no 2255 01:27:01,600 --> 01:27:05,160 sunbeam highlighting the Earth. 2256 01:27:05,160 --> 01:27:08,880 And why that cerulean color? 2257 01:27:08,880 --> 01:27:10,400 We can explain the wan 2258 01:27:10,400 --> 01:27:12,680 blueness of this little world 2259 01:27:12,680 --> 01:27:14,600 because we know it well. 2260 01:27:14,600 --> 01:27:16,000 Whether an alien scientist 2261 01:27:16,000 --> 01:27:17,360 newly arrived at the outskirts 2262 01:27:17,360 --> 01:27:19,760 of our solar system could reliably 2263 01:27:19,760 --> 01:27:22,760 deduce oceans and clouds in a 2264 01:27:22,760 --> 01:27:26,560 thickish atmosphere is less certain. 2265 01:27:26,560 --> 01:27:27,920 From this distant vantage 2266 01:27:27,920 --> 01:27:30,360 point, the Earth might not 2267 01:27:30,360 --> 01:27:33,760 seem of any particular interest. 2268 01:27:33,760 --> 01:27:36,840 But for us, it's different. 2269 01:27:36,840 --> 01:27:40,880 Consider again that dot. That's here. 2270 01:27:40,880 --> 01:27:44,040 That's home. That's us. 2271 01:27:44,040 --> 01:27:47,000 On it, everyone you love, 2272 01:27:47,000 --> 01:27:49,240 everyone you know, everyone 2273 01:27:49,240 --> 01:27:51,800 you ever heard of, every human being 2274 01:27:51,800 --> 01:27:54,120 who ever was, lived out their lives. 2275 01:27:55,760 --> 01:27:57,560 The aggregate of our joy and 2276 01:27:57,560 --> 01:28:00,200 suffering, thousands of 2277 01:28:00,200 --> 01:28:02,080 confident religions, ideologies, 2278 01:28:02,080 --> 01:28:02,720 and economic 2279 01:28:02,720 --> 01:28:05,080 doctrines, every hunter and 2280 01:28:05,080 --> 01:28:07,640 forager, every hero and 2281 01:28:07,640 --> 01:28:09,680 coward, every creator and destroyer 2282 01:28:09,680 --> 01:28:12,200 of civilization, every king 2283 01:28:12,200 --> 01:28:14,280 and peasant, every young 2284 01:28:14,280 --> 01:28:16,240 couple in love, every mother 2285 01:28:16,240 --> 01:28:16,980 and father, 2286 01:28:16,980 --> 01:28:19,720 father, hopeful child, inventor 2287 01:28:19,720 --> 01:28:22,440 and explorer, every teacher of 2288 01:28:22,440 --> 01:28:24,120 morals, every corrupt politician, 2289 01:28:24,960 --> 01:28:28,200 every superstar, every supreme 2290 01:28:28,200 --> 01:28:30,680 leader, every saint and sinner 2291 01:28:30,680 --> 01:28:32,880 in the history of our species 2292 01:28:32,880 --> 01:28:35,120 lived there, on the mote of 2293 01:28:35,120 --> 01:28:39,760 dust, suspended in a sunbeam. 2294 01:28:39,760 --> 01:28:42,560 The Earth is a very small 2295 01:28:42,560 --> 01:28:48,080 stage in a vast cosmic arena. 2296 01:28:48,080 --> 01:28:50,960 Think of the rivers of blood 2297 01:28:50,960 --> 01:28:52,800 spilled by all those generals 2298 01:28:52,800 --> 01:28:55,840 and emperors, so that in glory 2299 01:28:55,840 --> 01:28:57,320 and triumph they could become 2300 01:28:57,320 --> 01:29:00,040 the momentary masters of a 2301 01:29:00,040 --> 01:29:03,480 fraction of a dot. 2302 01:29:03,480 --> 01:29:05,240 Think of the endless cruelties 2303 01:29:05,240 --> 01:29:07,480 visited by the inhabitants of 2304 01:29:07,480 --> 01:29:09,640 one corner of this pixel 2305 01:29:09,640 --> 01:29:11,560 on the scarcely distinguishable 2306 01:29:11,560 --> 01:29:14,720 inhabitants of some other corner. 2307 01:29:14,720 --> 01:29:16,000 How frequent their 2308 01:29:16,000 --> 01:29:18,280 misunderstandings, how eager 2309 01:29:18,280 --> 01:29:20,360 they are to kill one another, 2310 01:29:20,360 --> 01:29:21,400 how fervent 2311 01:29:21,400 --> 01:29:26,640 their hatreds, our posturings, 2312 01:29:26,640 --> 01:29:28,720 our imagined self-importance, 2313 01:29:28,720 --> 01:29:30,480 the delusion that we have 2314 01:29:30,480 --> 01:29:32,200 some privileged position in 2315 01:29:32,200 --> 01:29:35,280 the universe are challenged by 2316 01:29:35,280 --> 01:29:38,360 this point of pale light. 2317 01:29:38,360 --> 01:29:42,360 Our planet is a lonely speck 2318 01:29:42,360 --> 01:29:46,560 in the great enveloping cosmic dark. 2319 01:29:46,560 --> 01:29:50,080 In our obscurity, in all this 2320 01:29:50,080 --> 01:29:53,360 vastness, there is no hint 2321 01:29:53,360 --> 01:29:55,480 that help will come from elsewhere 2322 01:29:55,480 --> 01:29:58,640 to save us from ourselves. 2323 01:29:58,640 --> 01:30:00,040 The Earth is the only world 2324 01:30:00,040 --> 01:30:02,960 known so far to harbor life. 2325 01:30:02,960 --> 01:30:04,640 There is nowhere else, at 2326 01:30:04,640 --> 01:30:06,440 least in the near future, to 2327 01:30:06,440 --> 01:30:08,960 which our species could migrate. 2328 01:30:08,960 --> 01:30:10,360 Visit? 2329 01:30:10,360 --> 01:30:11,600 Yes. 2330 01:30:11,600 --> 01:30:14,960 Settle? Not yet. 2331 01:30:14,960 --> 01:30:16,720 Like it or not, for the 2332 01:30:16,720 --> 01:30:19,000 moment, the Earth is where we 2333 01:30:19,000 --> 01:30:21,320 make our stand. 2334 01:30:21,320 --> 01:30:22,240 It has been said that 2335 01:30:22,240 --> 01:30:24,360 astronomy is a humbling and 2336 01:30:24,360 --> 01:30:27,160 character-building experience. 2337 01:30:27,160 --> 01:30:28,440 There is perhaps no better 2338 01:30:28,440 --> 01:30:29,880 demonstration of the folly of 2339 01:30:29,880 --> 01:30:32,840 human conceits than this distant 2340 01:30:32,840 --> 01:30:36,080 image of our tiny world. 2341 01:30:36,080 --> 01:30:38,720 To me, it underscores our 2342 01:30:38,720 --> 01:30:40,400 responsibility to deal more 2343 01:30:40,400 --> 01:30:42,800 kindly with one another and to 2344 01:30:42,800 --> 01:30:45,680 preserve and cherish the pale 2345 01:30:45,680 --> 01:30:48,800 blue dot, the only home we've 2346 01:30:48,800 --> 01:30:53,920 ever known. 2347 01:31:08,360 --> 01:31:09,440 We have considered the 2348 01:31:09,440 --> 01:31:11,280 destruction of worlds and the 2349 01:31:11,280 --> 01:31:14,200 end of civilizations, but there is 2350 01:31:14,200 --> 01:31:15,520 another perspective by which 2351 01:31:15,520 --> 01:31:17,600 to measure human endeavors. 2352 01:31:17,600 --> 01:31:19,640 Let me tell you a story 2353 01:31:19,640 --> 01:31:21,560 about the beginning. 2354 01:31:21,560 --> 01:31:23,720 Some 15 billion years ago, 2355 01:31:23,720 --> 01:31:26,080 our universe began with the 2356 01:31:26,080 --> 01:31:29,560 mightiest explosion of all time. 2357 01:31:29,560 --> 01:31:31,920 The universe expanded, cooled, 2358 01:31:31,920 --> 01:31:33,440 and darkened. 2359 01:31:33,440 --> 01:31:34,440 Energy condensed 2360 01:31:34,440 --> 01:31:36,040 into matter, mostly hydrogen 2361 01:31:36,040 --> 01:31:38,000 atoms, and these atoms 2362 01:31:38,000 --> 01:31:40,680 cumulated into vast clouds, 2363 01:31:40,680 --> 01:31:42,760 rushing away from each other that would 2364 01:31:42,760 --> 01:31:46,640 one day become the galaxies. 2365 01:31:46,640 --> 01:31:48,320 Within these galaxies, the 2366 01:31:48,320 --> 01:31:50,280 first generation of stars was 2367 01:31:50,280 --> 01:31:51,840 born, kindling 2368 01:31:51,840 --> 01:31:53,920 the energy hidden in matter, 2369 01:31:53,920 --> 01:31:56,720 flooding the cosmos with light. 2370 01:31:56,720 --> 01:31:58,560 Hydrogen atoms had made 2371 01:31:58,560 --> 01:32:03,560 suns and starlight. 2372 01:32:03,560 --> 01:32:05,480 There were in those times no 2373 01:32:05,480 --> 01:32:07,280 planets to receive the light 2374 01:32:07,280 --> 01:32:07,960 and no living 2375 01:32:07,960 --> 01:32:09,480 creatures to admire the 2376 01:32:09,480 --> 01:32:11,600 radiance of the heavens. 2377 01:32:11,600 --> 01:32:12,640 But deep in the stellar 2378 01:32:12,640 --> 01:32:14,200 furnaces, nuclear 2379 01:32:14,200 --> 01:32:15,560 fusion was creating the 2380 01:32:15,560 --> 01:32:17,720 heavier atoms, carbon and 2381 01:32:17,720 --> 01:32:20,200 oxygen, silicon and iron. 2382 01:32:20,200 --> 01:32:21,240 These elements, 2383 01:32:21,240 --> 01:32:23,400 the ash left by hydrogen, 2384 01:32:23,400 --> 01:32:25,280 were the raw materials from 2385 01:32:25,280 --> 01:32:26,880 which planets and life would 2386 01:32:26,880 --> 01:32:28,720 later arise. 2387 01:32:28,720 --> 01:32:29,920 At first, the heavy elements 2388 01:32:29,920 --> 01:32:31,520 were trapped in the hearts of 2389 01:32:31,520 --> 01:32:32,760 the stars. 2390 01:32:32,760 --> 01:32:34,680 But massive stars soon 2391 01:32:34,680 --> 01:32:36,480 exhausted their fuel, and in 2392 01:32:36,480 --> 01:32:38,360 their death throes, returned 2393 01:32:38,360 --> 01:32:39,640 most of their substance back 2394 01:32:39,640 --> 01:32:41,200 into space. 2395 01:32:41,200 --> 01:32:42,520 Interstellar gas became 2396 01:32:42,520 --> 01:32:47,080 enriched in heavy elements. 2397 01:32:47,080 --> 01:32:48,920 In the Milky Way galaxy, the 2398 01:32:48,920 --> 01:32:50,200 matter of the cosmos was 2399 01:32:50,200 --> 01:32:53,040 recycled into new generations of stars, 2400 01:32:53,040 --> 01:32:55,360 now rich in heavy atoms, a 2401 01:32:55,360 --> 01:33:00,560 legacy from their stellar ancestors. 2402 01:33:00,560 --> 01:33:03,000 And in the cold of interstellar space, 2403 01:33:03,000 --> 01:33:05,080 great turbulent clouds were 2404 01:33:05,080 --> 01:33:06,880 gathered by gravity and 2405 01:33:06,880 --> 01:33:11,840 stirred by starlight. 2406 01:33:11,840 --> 01:33:13,480 In their depths, the heavy 2407 01:33:13,480 --> 01:33:15,200 atoms condensed into grains of 2408 01:33:15,200 --> 01:33:16,880 rocky dust and ice 2409 01:33:16,880 --> 01:33:20,240 and complex carbon-based molecules. 2410 01:33:20,240 --> 01:33:21,680 In accordance with the laws 2411 01:33:21,680 --> 01:33:23,480 of physics and chemistry, 2412 01:33:23,480 --> 01:33:25,560 hydrogen atoms had brought 2413 01:33:25,560 --> 01:33:29,000 forth the stuff of life. 2414 01:33:29,000 --> 01:33:30,440 In other clouds, more 2415 01:33:30,440 --> 01:33:31,960 massive aggregates of gas and 2416 01:33:31,960 --> 01:33:35,280 dust formed later generations of stars. 2417 01:33:35,280 --> 01:33:35,680 As new 2418 01:33:35,680 --> 01:33:37,640 stars were formed, tiny 2419 01:33:37,640 --> 01:33:38,920 condensations of matter 2420 01:33:38,920 --> 01:33:41,160 accreted near them, inconspicuous 2421 01:33:41,160 --> 01:33:43,120 motes of rock and metal, ice 2422 01:33:43,120 --> 01:33:46,320 and gas, that would become the planets. 2423 01:33:46,320 --> 01:33:46,680 And on 2424 01:33:46,680 --> 01:33:47,960 these worlds, as in 2425 01:33:47,960 --> 01:33:49,920 interstellar clouds, organic 2426 01:33:49,920 --> 01:33:52,360 molecules formed, made of atoms 2427 01:33:52,360 --> 01:33:55,400 that had been cooked inside the stars. 2428 01:33:55,400 --> 01:33:57,200 In the tide pools and oceans 2429 01:33:57,200 --> 01:33:58,680 of many worlds, 2430 01:33:58,680 --> 01:34:00,200 molecules were destroyed by 2431 01:34:00,200 --> 01:34:03,200 sunlight and assembled by chemistry. 2432 01:34:03,200 --> 01:34:05,440 One day, among these natural 2433 01:34:05,440 --> 01:34:07,720 experiments, a molecule arose 2434 01:34:07,720 --> 01:34:09,600 that quite by accident was 2435 01:34:09,600 --> 01:34:14,120 able to make crude copies of itself. 2436 01:34:14,120 --> 01:34:15,160 As time passed, 2437 01:34:15,160 --> 01:34:17,800 self-replication became more accurate. 2438 01:34:17,800 --> 01:34:19,080 Those molecules that copied 2439 01:34:19,080 --> 01:34:21,600 better, produced more copies. 2440 01:34:21,600 --> 01:34:23,720 Natural selection was underway. 2441 01:34:24,360 --> 01:34:26,200 Elaborate molecular machines 2442 01:34:26,200 --> 01:34:27,520 had evolved. 2443 01:34:27,520 --> 01:34:33,840 Slowly, imperceptibly, life had begun. 2444 01:34:33,840 --> 01:34:35,080 Collectives of organic 2445 01:34:35,080 --> 01:34:36,240 molecules evolved 2446 01:34:36,240 --> 01:34:38,360 into one-celled organisms. 2447 01:34:38,360 --> 01:34:41,000 These produced multi-celled colonies. 2448 01:34:41,000 --> 01:34:42,200 Their various parts 2449 01:34:42,200 --> 01:34:44,720 became specialized organs. 2450 01:34:44,720 --> 01:34:46,040 Some colonies attached 2451 01:34:46,040 --> 01:34:48,240 themselves to the sea floor. 2452 01:34:48,240 --> 01:34:52,160 Others swam freely. 2453 01:34:52,160 --> 01:34:53,880 Eyes evolved, and now the 2454 01:34:53,880 --> 01:34:55,400 cosmos could see. 2455 01:34:55,400 --> 01:34:56,720 Living things moved on 2456 01:34:56,720 --> 01:34:58,800 to colonize the land. 2457 01:34:58,800 --> 01:35:00,800 The reptiles held sway for a 2458 01:35:00,800 --> 01:35:02,640 time, but they gave way to 2459 01:35:02,640 --> 01:35:04,440 small warm-blooded creatures 2460 01:35:04,440 --> 01:35:06,040 with bigger brains who 2461 01:35:06,040 --> 01:35:07,880 developed dexterity and 2462 01:35:07,880 --> 01:35:10,200 curiosity about their environment. 2463 01:35:10,200 --> 01:35:12,440 They learned to use tools and fire and 2464 01:35:12,440 --> 01:35:15,200 language, star stuff, the ash 2465 01:35:15,200 --> 01:35:16,880 of stellar alchemy, had 2466 01:35:16,880 --> 01:35:20,320 emerged into consciousness. 2467 01:35:20,320 --> 01:35:22,600 We are a way for the cosmos 2468 01:35:22,600 --> 01:35:23,640 to know itself. 2469 01:35:24,800 --> 01:35:25,920 We are creatures of the 2470 01:35:25,920 --> 01:35:27,760 cosmos and have always 2471 01:35:27,760 --> 01:35:30,520 hungered to know our origins, 2472 01:35:30,520 --> 01:35:31,400 to understand 2473 01:35:31,400 --> 01:35:34,120 our connection with the universe. 2474 01:35:34,120 --> 01:35:37,080 How did everything come to be? 2475 01:35:37,080 --> 01:35:38,320 Every culture on the planet 2476 01:35:38,320 --> 01:35:40,160 has devised its own response 2477 01:35:40,160 --> 01:35:43,560 to the riddle posed by the universe. 2478 01:35:43,560 --> 01:35:45,320 Every culture celebrates the 2479 01:35:45,320 --> 01:35:47,960 cycles of life and nature. 2480 01:35:47,960 --> 01:35:49,240 There are many different ways 2481 01:35:49,240 --> 01:35:51,280 of being human. 2482 01:35:51,280 --> 01:35:52,400 But an extraterrestrial 2483 01:35:52,400 --> 01:35:53,920 visitor, examining the 2484 01:35:53,920 --> 01:35:56,200 differences among human societies, 2485 01:35:56,200 --> 01:35:57,920 would find those differences 2486 01:35:57,920 --> 01:36:01,640 trivial compared to the similarities. 2487 01:36:01,640 --> 01:36:05,240 We are one species. 2488 01:36:05,240 --> 01:36:09,160 We are starstuff harvesting starlight. 2489 01:36:09,160 --> 01:36:11,160 Our lives, our past 2490 01:36:11,160 --> 01:36:14,360 and our future are tied to the Sun, 2491 01:36:14,360 --> 01:36:17,160 the Moon and the stars. 2492 01:36:17,160 --> 01:36:19,080 Our ancestors knew that their 2493 01:36:19,080 --> 01:36:20,720 survival depended on 2494 01:36:20,720 --> 01:36:22,280 understanding the heavens. 2495 01:36:22,280 --> 01:36:23,960 They built observatories and 2496 01:36:23,960 --> 01:36:25,800 computers to predict the 2497 01:36:25,800 --> 01:36:27,640 changing of the seasons by the 2498 01:36:27,640 --> 01:36:30,920 motions in the skies. 2499 01:36:30,920 --> 01:36:32,120 The discovery that there is 2500 01:36:32,120 --> 01:36:33,440 order in the universe, that 2501 01:36:33,440 --> 01:36:34,080 there are laws 2502 01:36:34,080 --> 01:36:36,280 of nature is the foundation 2503 01:36:36,280 --> 01:36:41,200 on which science builds today. 2504 01:36:41,200 --> 01:36:42,680 Science is a collective 2505 01:36:42,680 --> 01:36:44,760 enterprise that embraces many 2506 01:36:44,760 --> 01:36:47,760 cultures and spans the generations. 2507 01:36:47,760 --> 01:36:49,800 In every age, and sometimes 2508 01:36:49,800 --> 01:36:51,840 in the most unlikely places, 2509 01:36:51,840 --> 01:36:53,680 there are those who wish with a great 2510 01:36:53,680 --> 01:36:56,560 passion to understand the world. 2511 01:36:56,560 --> 01:36:57,720 There is no way of knowing 2512 01:36:57,720 --> 01:36:58,880 where the next discovery will 2513 01:36:58,880 --> 01:36:59,880 come from. 2514 01:36:59,880 --> 01:37:02,720 What dream of the mind's eye 2515 01:37:02,720 --> 01:37:07,200 will remake the world? 2516 01:37:07,200 --> 01:37:11,760 These dreams begin as impossibilities. 2517 01:37:11,760 --> 01:37:13,960 Once, even to see a planet through a 2518 01:37:13,960 --> 01:37:16,320 telescope was an astonishment, 2519 01:37:16,320 --> 01:37:18,160 but we studied these worlds 2520 01:37:18,160 --> 01:37:19,200 and figured out how 2521 01:37:19,200 --> 01:37:21,040 they moved in their orbits, 2522 01:37:21,040 --> 01:37:22,480 and soon we were planning 2523 01:37:22,480 --> 01:37:23,520 voyages of discovery 2524 01:37:24,200 --> 01:37:25,960 beyond the Earth, and sending 2525 01:37:25,960 --> 01:37:28,840 robot explorers to the planets 2526 01:37:28,840 --> 01:37:31,280 and the stars. 2527 01:37:31,280 --> 01:37:33,160 We humans long to be 2528 01:37:33,160 --> 01:37:35,480 connected with our origins, so 2529 01:37:35,480 --> 01:37:38,280 we create rituals. 2530 01:37:38,280 --> 01:37:39,520 Science is another way to 2531 01:37:39,520 --> 01:37:41,000 express this longing. 2532 01:37:41,000 --> 01:37:42,440 It also connects us with our 2533 01:37:42,440 --> 01:37:44,920 origins, and it too has its 2534 01:37:44,920 --> 01:37:48,000 rituals and its commandments. 2535 01:37:48,000 --> 01:37:50,160 Its only sacred truth is that 2536 01:37:50,160 --> 01:37:52,880 there are no sacred truths. 2537 01:37:52,880 --> 01:37:54,240 All assumptions must be 2538 01:37:54,240 --> 01:37:55,680 critically examined. 2539 01:37:55,680 --> 01:37:58,840 Arguments from authority are worthless. 2540 01:37:58,840 --> 01:38:00,200 Whatever is inconsistent with 2541 01:38:00,200 --> 01:38:02,000 the facts, no matter how fond 2542 01:38:02,000 --> 01:38:03,520 of it we are, must be 2543 01:38:03,520 --> 01:38:07,560 discarded or revised. 2544 01:38:07,560 --> 01:38:09,840 Science is not perfect. 2545 01:38:09,840 --> 01:38:13,600 It's often misused. It's only a tool. 2546 01:38:13,600 --> 01:38:15,720 But it's the best tool we have. 2547 01:38:15,720 --> 01:38:18,680 Self-correcting, ever-changing, 2548 01:38:18,680 --> 01:38:21,680 applicable to everything. 2549 01:38:21,680 --> 01:38:24,400 With this tool, we vanquish 2550 01:38:24,400 --> 01:38:27,440 the impossible. 2551 01:38:27,440 --> 01:38:29,520 With the methods of science, 2552 01:38:29,520 --> 01:38:33,720 we have begun to explore the cosmos. 2553 01:38:33,720 --> 01:38:35,800 For the first time, scientific 2554 01:38:35,800 --> 01:38:39,880 discoveries are widely accessible. 2555 01:38:39,880 --> 01:38:41,920 Our machines, the products of 2556 01:38:41,920 --> 01:38:44,440 our science, are now beyond 2557 01:38:44,440 --> 01:38:46,800 the orbit of Saturn. 2558 01:38:46,800 --> 01:38:48,520 A preliminary spacecraft 2559 01:38:48,520 --> 01:38:50,120 reconnaissance has been made 2560 01:38:50,120 --> 01:38:53,160 of 20 new worlds. 2561 01:38:53,160 --> 01:38:55,040 We have learned to value 2562 01:38:55,040 --> 01:38:56,760 careful observations, to 2563 01:38:56,760 --> 01:38:58,240 respect the facts even when 2564 01:38:58,240 --> 01:38:59,600 they are disquieting 2565 01:38:59,600 --> 01:39:00,880 and they seem to contradict 2566 01:39:00,880 --> 01:39:03,840 conventional wisdom. 2567 01:39:03,840 --> 01:39:05,840 We humans have seen the atoms 2568 01:39:05,840 --> 01:39:07,640 which constitute all of matter 2569 01:39:07,640 --> 01:39:09,640 and the forces that sculpt this 2570 01:39:09,640 --> 01:39:12,320 world and others. 2571 01:39:12,320 --> 01:39:13,640 We have found that the 2572 01:39:13,640 --> 01:39:15,280 molecules of life are easily 2573 01:39:15,280 --> 01:39:17,680 formed under conditions common 2574 01:39:17,680 --> 01:39:19,920 throughout the cosmos. 2575 01:39:19,920 --> 01:39:21,320 We have mapped the molecular 2576 01:39:21,320 --> 01:39:23,520 machines at the heart of life. 2577 01:39:23,520 --> 01:39:25,360 We have discovered a microcosm 2578 01:39:25,360 --> 01:39:27,240 in a drop of water. 2579 01:39:27,240 --> 01:39:28,200 We have peered into the 2580 01:39:28,200 --> 01:39:30,280 bloodstream and down on our 2581 01:39:30,280 --> 01:39:31,600 stormy planet 2582 01:39:31,600 --> 01:39:34,560 to see the Earth as a single organism. 2583 01:39:34,560 --> 01:39:36,080 We have found volcanoes on 2584 01:39:36,080 --> 01:39:39,360 other worlds and explosions on the Sun, 2585 01:39:39,360 --> 01:39:40,880 studied comets from the depths 2586 01:39:40,880 --> 01:39:42,120 of space, 2587 01:39:42,120 --> 01:39:45,880 traced their origins and destinies, 2588 01:39:45,880 --> 01:39:47,800 Listened to pulsars and 2589 01:39:47,800 --> 01:39:50,960 searched for other civilizations. 2590 01:39:50,960 --> 01:39:53,040 We humans have set foot on 2591 01:39:53,040 --> 01:39:55,120 another world, in a place 2592 01:39:55,120 --> 01:39:57,280 called the Sea of Tranquility, 2593 01:39:57,280 --> 01:39:59,080 an astonishing achievement for 2594 01:39:59,080 --> 01:40:01,080 creatures such as we, whose 2595 01:40:01,080 --> 01:40:02,960 earliest footsteps, three and 2596 01:40:02,960 --> 01:40:04,840 a half million years old, are 2597 01:40:04,840 --> 01:40:06,880 preserved in the volcanic ash 2598 01:40:06,880 --> 01:40:09,560 of East Africa. 2599 01:40:09,560 --> 01:40:10,720 These are some of the things 2600 01:40:10,720 --> 01:40:13,120 that hydrogen atoms do, given 2601 01:40:13,120 --> 01:40:19,240 15 billion years of cosmic evolution. 2602 01:40:19,240 --> 01:40:21,560 It has the sound of epic 2603 01:40:21,560 --> 01:40:23,640 myth, but it's simply a 2604 01:40:23,640 --> 01:40:24,920 description of the evolution 2605 01:40:24,920 --> 01:40:27,720 of the cosmos as revealed by 2606 01:40:27,720 --> 01:40:29,840 science in our time. 2607 01:40:29,840 --> 01:40:33,120 And we, we who embody the 2608 01:40:33,120 --> 01:40:34,920 local eyes and ears and 2609 01:40:34,920 --> 01:40:37,520 thoughts and feelings of the cosmos, 2610 01:40:37,520 --> 01:40:39,920 We've begun, at last, to 2611 01:40:39,920 --> 01:40:41,920 wonder about our origins. 2612 01:40:41,920 --> 01:40:45,320 Star stuff, contemplating the stars. 2613 01:40:45,320 --> 01:40:47,440 Organized collections of ten 2614 01:40:47,440 --> 01:40:50,160 billion, billion, billion atoms, 2615 01:40:50,160 --> 01:40:52,440 contemplating the evolution of matter, 2616 01:40:52,440 --> 01:40:54,920 tracing that long path by 2617 01:40:54,920 --> 01:40:57,080 which it arrived at consciousness 2618 01:40:57,080 --> 01:40:59,080 here on the planet Earth and, 2619 01:40:59,080 --> 01:41:02,440 perhaps, throughout the cosmos. 2620 01:41:02,440 --> 01:41:05,080 Our loyalties are to the 2621 01:41:05,080 --> 01:41:07,920 species and the planet. 2622 01:41:07,920 --> 01:41:09,920 We speak for Earth. 2623 01:41:09,920 --> 01:41:11,880 Our obligation to survive and 2624 01:41:11,880 --> 01:41:14,360 flourish is owed not just to 2625 01:41:14,360 --> 01:41:16,760 ourselves, but also to that 2626 01:41:16,760 --> 01:41:20,200 cosmos, ancient and vast, from 2627 01:41:20,200 --> 01:41:23,240 which we spring. 2628 01:41:44,160 --> 01:41:46,240 In the vision of a dream, I 2629 01:41:46,240 --> 01:41:48,640 once imagined myself searching 2630 01:41:48,640 --> 01:41:49,960 for other civilizations 2631 01:41:49,960 --> 01:41:52,000 in the cosmos. 2632 01:41:52,000 --> 01:41:53,400 Among a hundred billion 2633 01:41:53,400 --> 01:41:55,160 galaxies and a billion 2634 01:41:55,160 --> 01:41:57,520 trillion stars, life and 2635 01:41:57,520 --> 01:41:58,760 intelligence should 2636 01:41:58,760 --> 01:42:01,720 have arisen on many worlds. 2637 01:42:01,720 --> 01:42:05,520 Some worlds are barren and desolate. 2638 01:42:05,520 --> 01:42:08,360 On them, life never began, or 2639 01:42:08,360 --> 01:42:09,640 may have been extinguished in 2640 01:42:09,640 --> 01:42:12,200 some cosmic catastrophe. 2641 01:42:12,200 --> 01:42:13,560 There may be worlds rich in 2642 01:42:13,560 --> 01:42:16,000 life, but not yet evolved to 2643 01:42:16,000 --> 01:42:19,360 intelligence and high technology. 2644 01:42:19,360 --> 01:42:20,680 There may be civilizations 2645 01:42:20,680 --> 01:42:22,920 that achieve technology and 2646 01:42:22,920 --> 01:42:24,480 then promptly use it to 2647 01:42:24,480 --> 01:42:27,160 destroy themselves. 2648 01:42:27,160 --> 01:42:28,760 And perhaps there are also 2649 01:42:28,760 --> 01:42:30,720 beings who learn to live with 2650 01:42:30,720 --> 01:42:32,840 their technology and themselves 2651 01:42:32,840 --> 01:42:35,760 beings who endure and become 2652 01:42:35,760 --> 01:42:40,320 citizens of the cosmos. 2653 01:42:40,320 --> 01:42:42,360 Immersed in these thoughts, I 2654 01:42:42,360 --> 01:42:43,560 found myself approaching a 2655 01:42:43,560 --> 01:42:46,120 world that was clearly inhabited, 2656 01:42:46,120 --> 01:42:48,800 a world I had visited before. 2657 01:42:48,800 --> 01:42:51,280 I saw a planet encompassed by 2658 01:42:51,280 --> 01:42:53,960 light and recognized the 2659 01:42:53,960 --> 01:42:59,480 signature of intelligence, but suddenly 2660 01:42:59,480 --> 01:43:05,720 darkness, total and absolute. 2661 01:43:05,720 --> 01:43:07,000 Their world society had 2662 01:43:07,000 --> 01:43:09,280 failed, they had made the 2663 01:43:09,280 --> 01:43:12,440 ultimate mistake. 2664 01:43:12,440 --> 01:43:18,240 I felt a longing to return to Earth. 2665 01:43:18,240 --> 01:43:19,760 The television transmissions of 2666 01:43:19,760 --> 01:43:21,800 Earth rushed past me, 2667 01:43:21,800 --> 01:43:23,740 expanding away from our planet at 2668 01:43:23,740 --> 01:43:24,440 at the speed of light. 2669 01:43:24,440 --> 01:43:26,680 There can be no whitewash at 2670 01:43:26,680 --> 01:43:28,160 the White House. 2671 01:43:28,160 --> 01:43:30,080 A series of record oil company profits... 2672 01:43:31,480 --> 01:43:32,560 If the serious course of 2673 01:43:32,560 --> 01:43:33,960 events continue, 2674 01:43:33,960 --> 01:43:36,320 foreign ministers are at this moment... 2675 01:43:36,320 --> 01:43:42,560 Oh, please stand by. Stand by. 2676 01:43:42,560 --> 01:43:46,240 Then, suddenly, silence. 2677 01:43:46,240 --> 01:43:50,320 Total and absolute. 2678 01:43:50,320 --> 01:43:53,120 Had we destroyed our home? 2679 01:43:53,120 --> 01:43:56,000 What had we done to the Earth? 2680 01:43:56,000 --> 01:43:57,200 There had been many ways for 2681 01:43:57,200 --> 01:43:59,320 life to perish at our hands. 2682 01:43:59,320 --> 01:44:01,880 We had poisoned the air and water. 2683 01:44:01,880 --> 01:44:04,440 We had ravaged the land. 2684 01:44:04,440 --> 01:44:07,080 Perhaps we had changed the climate. 2685 01:44:07,080 --> 01:44:10,160 Could it have been a plague? 2686 01:44:10,160 --> 01:44:14,800 Or nuclear war? 2687 01:44:14,800 --> 01:44:17,440 So it was nuclear war, a 2688 01:44:17,440 --> 01:44:20,920 full nuclear exchange. 2689 01:44:20,920 --> 01:44:22,720 There would be no more big 2690 01:44:22,720 --> 01:44:26,360 questions, no more answers. 2691 01:44:26,360 --> 01:44:30,080 Never again a love or a child. 2692 01:44:30,080 --> 01:44:31,880 No descendants to remember us 2693 01:44:31,880 --> 01:44:33,560 and be proud. 2694 01:44:33,560 --> 01:44:36,880 No more voyages to the stars. 2695 01:44:36,880 --> 01:44:44,880 No more songs from the Earth. 2696 01:44:44,880 --> 01:44:47,440 I saw East Africa and 2697 01:44:47,440 --> 01:44:49,040 thought, a few million years 2698 01:44:49,040 --> 01:44:50,920 ago, we humans took our first 2699 01:44:50,920 --> 01:44:52,320 steps there. 2700 01:44:52,320 --> 01:44:55,040 Our brains grew and changed. 2701 01:44:55,040 --> 01:44:56,600 The old parts began to be 2702 01:44:56,600 --> 01:44:58,680 guided by the new parts. 2703 01:44:58,680 --> 01:45:00,320 And this made us human, with 2704 01:45:00,320 --> 01:45:04,480 compassion, foresight, and reason. 2705 01:45:04,480 --> 01:45:06,960 But instead, we listened to 2706 01:45:06,960 --> 01:45:09,240 that reptilian voice within us, 2707 01:45:09,240 --> 01:45:11,200 counseling fear, 2708 01:45:11,200 --> 01:45:14,760 territoriality, aggression. 2709 01:45:14,760 --> 01:45:17,400 We accepted the products of science. 2710 01:45:17,400 --> 01:45:21,440 We rejected its methods. 2711 01:45:21,440 --> 01:45:23,000 Maybe the reptiles will evolve 2712 01:45:23,000 --> 01:45:24,920 intelligence once more. 2713 01:45:24,920 --> 01:45:27,320 Perhaps one day, there will 2714 01:45:27,320 --> 01:45:29,760 be civilizations again on Earth. 2715 01:45:29,760 --> 01:45:31,200 There will be life. 2716 01:45:31,200 --> 01:45:33,720 There will be intelligence. 2717 01:45:33,720 --> 01:45:35,680 But there will be no more humans. 2718 01:46:16,520 --> 01:46:18,480 Two megatons. 2719 01:46:18,480 --> 01:46:21,560 Coventry and Rotterdam, Dresden 2720 01:46:21,560 --> 01:46:23,800 and Tokyo, all the death that 2721 01:46:23,800 --> 01:46:25,040 reigned from the skies 2722 01:46:25,040 --> 01:46:29,200 between 1939 and 1945, 100,000 2723 01:46:29,200 --> 01:46:33,440 blockbusters, two megatons. 2724 01:46:33,440 --> 01:46:36,000 Today, two megatons is the 2725 01:46:36,000 --> 01:46:37,080 equivalent of a single 2726 01:46:37,080 --> 01:46:38,160 thermonuclear bomb, 2727 01:46:38,160 --> 01:46:40,200 one bomb with the destructive 2728 01:46:40,200 --> 01:46:44,120 force of the Second World War. 2729 01:46:44,120 --> 01:46:45,160 But there are tens of 2730 01:46:45,160 --> 01:46:46,880 thousands of nuclear weapons. 2731 01:46:46,880 --> 01:46:49,840 No place on the planet is safe. 2732 01:46:49,840 --> 01:46:52,600 The energy contained in these weapons, 2733 01:46:52,600 --> 01:46:55,200 Genies of death patiently 2734 01:46:55,200 --> 01:46:59,200 awaiting the rubbing of the lamps. 2735 01:46:59,200 --> 01:47:02,120 Totals far more than 10,000 megatons, 2736 01:47:02,120 --> 01:47:04,200 but with the destruction 2737 01:47:04,200 --> 01:47:05,880 concentrated efficiently. 2738 01:47:05,880 --> 01:47:07,800 Not over six years, but over 2739 01:47:07,800 --> 01:47:09,320 a few hours. 2740 01:47:09,320 --> 01:47:11,640 A blockbuster for every family 2741 01:47:11,640 --> 01:47:13,480 on the planet. 2742 01:47:13,480 --> 01:47:16,400 A World War II every second 2743 01:47:16,400 --> 01:47:22,840 for the length of a lazy afternoon. 2744 01:47:26,000 --> 01:47:27,800 The bomb dropped on Hiroshima 2745 01:47:27,800 --> 01:47:30,480 killed 70,000 people. 2746 01:47:30,480 --> 01:47:32,920 In a full nuclear exchange, 2747 01:47:32,920 --> 01:47:35,840 in the paroxysm of global death, 2748 01:47:35,840 --> 01:47:37,080 the equivalent of a million 2749 01:47:37,080 --> 01:47:38,880 Hiroshima bombs 2750 01:47:38,880 --> 01:47:41,800 would be dropped all over the world. 2751 01:47:41,800 --> 01:47:43,000 But in such an exchange, not 2752 01:47:43,000 --> 01:47:44,520 everyone would be killed 2753 01:47:44,520 --> 01:47:45,640 by the blast and the 2754 01:47:45,640 --> 01:47:48,360 firestorm and the immediate radiation. 2755 01:47:48,360 --> 01:47:50,840 There would be other agonies, 2756 01:47:50,840 --> 01:47:52,160 the loss of loved ones, 2757 01:47:52,160 --> 01:47:54,720 the legions of the burned and 2758 01:47:54,720 --> 01:47:56,960 blinded and mutilated, 2759 01:47:56,960 --> 01:47:58,920 the absence of medical care, 2760 01:48:32,000 --> 01:48:34,360 in military endeavors. 2761 01:48:34,360 --> 01:48:35,640 How would we explain all this 2762 01:48:35,640 --> 01:48:37,280 to a dispassionate 2763 01:48:37,280 --> 01:48:38,920 extraterrestrial observer? 2764 01:48:38,920 --> 01:48:41,360 What account would we give of 2765 01:48:41,360 --> 01:48:47,040 our stewardship of the planet Earth? 2766 01:48:47,040 --> 01:48:48,160 From an extraterrestrial 2767 01:48:48,160 --> 01:48:50,440 perspective, our global 2768 01:48:50,440 --> 01:48:52,960 civilization is clearly on the edge 2769 01:48:52,960 --> 01:48:54,520 of failure in the most 2770 01:48:54,520 --> 01:48:56,240 important task it faces, 2771 01:48:56,240 --> 01:48:57,560 preserving the lives and 2772 01:48:57,560 --> 01:48:58,720 well-being of its 2773 01:48:58,720 --> 01:49:00,440 citizens and the future 2774 01:49:00,440 --> 01:49:03,000 habitability of the planet. 2775 01:49:03,000 --> 01:49:05,080 But if we're willing to live 2776 01:49:05,080 --> 01:49:06,440 with the growing likelihood of 2777 01:49:06,440 --> 01:49:08,400 nuclear war, shouldn't we also 2778 01:49:08,400 --> 01:49:09,880 be willing to explore 2779 01:49:09,880 --> 01:49:11,960 vigorously every possible means 2780 01:49:11,960 --> 01:49:13,760 to prevent nuclear war? 2781 01:49:13,760 --> 01:49:16,800 shouldn't we consider in every nation 2782 01:49:16,800 --> 01:49:17,960 major changes in the 2783 01:49:17,960 --> 01:49:19,840 traditional ways of doing things, 2784 01:49:19,840 --> 01:49:22,040 a fundamental restructuring of 2785 01:49:22,040 --> 01:49:22,720 economic, 2786 01:49:22,720 --> 01:49:23,640 political, social, and 2787 01:49:23,640 --> 01:49:26,040 religious institutions? 2788 01:49:26,040 --> 01:49:27,280 We've reached a point where 2789 01:49:27,280 --> 01:49:28,360 there can be 2790 01:49:28,360 --> 01:49:30,400 no more special interests or 2791 01:49:30,400 --> 01:49:31,320 special cases. 2792 01:49:31,320 --> 01:49:33,200 Nuclear arms threaten every 2793 01:49:33,200 --> 01:49:36,160 person on the Earth. 2794 01:49:36,160 --> 01:49:38,200 Fundamental changes in society 2795 01:49:38,200 --> 01:49:40,200 are sometimes labeled 2796 01:49:40,200 --> 01:49:43,840 of impractical or contrary to 2797 01:49:43,840 --> 01:49:45,240 human nature, 2798 01:49:45,240 --> 01:49:46,320 as if nuclear war were 2799 01:49:46,320 --> 01:49:48,200 practical or as if there were 2800 01:49:48,200 --> 01:49:51,400 only one human nature. 2801 01:49:51,400 --> 01:49:53,240 But fundamental changes can 2802 01:49:53,240 --> 01:49:54,120 clearly be made. 2803 01:49:54,120 --> 01:49:56,280 We're surrounded by them. 2804 01:49:56,280 --> 01:49:57,800 In the last two centuries, 2805 01:49:57,800 --> 01:49:59,240 abject slavery, 2806 01:49:59,240 --> 01:50:00,360 which was with us for 2807 01:50:00,360 --> 01:50:01,960 thousands of years, 2808 01:50:01,960 --> 01:50:03,200 has almost entirely been 2809 01:50:03,200 --> 01:50:04,960 eliminated in a stirring 2810 01:50:04,960 --> 01:50:07,160 worldwide revolution. 2811 01:50:07,160 --> 01:50:09,480 Women, systematically mistreated 2812 01:50:09,480 --> 01:50:10,880 for millennia, 2813 01:50:10,880 --> 01:50:12,200 are gradually gaining the 2814 01:50:12,200 --> 01:50:14,000 political and economic power 2815 01:50:14,000 --> 01:50:16,080 traditionally denied to them. 2816 01:50:16,080 --> 01:50:19,280 The old appeals to racial, 2817 01:50:19,280 --> 01:50:21,520 sexual, and religious chauvinism 2818 01:50:21,520 --> 01:50:24,960 and to rabid nationalist fervor 2819 01:50:24,960 --> 01:50:27,000 are beginning not to work. 2820 01:50:27,000 --> 01:50:28,640 A new consciousness is developing 2821 01:50:28,640 --> 01:50:31,000 which sees the Earth as a 2822 01:50:31,000 --> 01:50:32,680 single organism 2823 01:50:32,680 --> 01:50:34,440 and recognizes that an 2824 01:50:34,440 --> 01:50:38,720 organism at war with itself is doomed. 2825 01:50:38,720 --> 01:50:46,440 We are one planet. 2826 01:50:46,440 --> 01:50:47,800 We who cannot even put our 2827 01:50:47,800 --> 01:50:50,160 own planetary home in order, 2828 01:50:50,160 --> 01:50:53,040 riven with rivalries and hatreds, 2829 01:50:53,040 --> 01:50:56,480 are we to venture out into space? 2830 01:50:56,480 --> 01:50:57,440 By the time we're ready to 2831 01:50:57,440 --> 01:50:59,160 settle even the nearest other 2832 01:50:59,160 --> 01:51:01,040 planetary systems, 2833 01:51:01,040 --> 01:51:03,200 we will have changed. 2834 01:51:03,200 --> 01:51:04,520 The simple passage of so many 2835 01:51:04,520 --> 01:51:07,000 generations will have changed us. 2836 01:51:07,000 --> 01:51:10,000 necessity will have changed us. 2837 01:51:10,000 --> 01:51:13,720 We're an adaptable species. 2838 01:51:13,720 --> 01:51:14,960 It will not be we who 2839 01:51:14,960 --> 01:51:17,160 reach Alpha Centauri and the 2840 01:51:17,160 --> 01:51:18,840 other nearby stars. 2841 01:51:18,840 --> 01:51:20,680 It will be a species very 2842 01:51:20,680 --> 01:51:22,800 like us, but with more of 2843 01:51:22,800 --> 01:51:25,320 our strengths and fewer of 2844 01:51:25,320 --> 01:51:27,040 our weaknesses. 2845 01:51:27,040 --> 01:51:27,400 More 2846 01:51:27,400 --> 01:51:31,240 confident, far-seeing, capable 2847 01:51:31,240 --> 01:51:33,040 and prudent. 2848 01:51:33,040 --> 01:51:35,800 For all our failings, despite our 2849 01:51:35,800 --> 01:51:37,120 limitations and fallibilities, 2850 01:51:37,120 --> 01:51:42,680 we humans are capable of greatness. 2851 01:51:42,680 --> 01:51:43,320 What new 2852 01:51:43,320 --> 01:51:45,320 wonders undreamt of in our 2853 01:51:45,320 --> 01:51:47,840 time will we have wrought in 2854 01:51:47,840 --> 01:51:51,560 another generation and another? 2855 01:51:51,560 --> 01:51:53,440 How far will our nomadic 2856 01:51:53,440 --> 01:51:55,640 species have wandered by the 2857 01:51:55,640 --> 01:51:56,360 end of the next 2858 01:51:56,360 --> 01:52:00,600 century and the next millennium? 2859 01:52:00,600 --> 01:52:03,320 Our remote descendants safely 2860 01:52:03,320 --> 01:52:04,280 arrayed on many 2861 01:52:04,280 --> 01:52:05,320 worlds through the solar 2862 01:52:05,320 --> 01:52:10,200 system and beyond, will be unified. 2863 01:52:10,200 --> 01:52:12,840 By their common heritage, by 2864 01:52:12,840 --> 01:52:14,200 their regard for their home 2865 01:52:14,200 --> 01:52:17,600 planet, and by the knowledge 2866 01:52:17,600 --> 01:52:19,240 that whatever other life may 2867 01:52:19,240 --> 01:52:21,240 be, the only humans in all 2868 01:52:21,240 --> 01:52:24,520 the universe come from Earth, 2869 01:52:24,520 --> 01:52:26,640 they will gaze up and strain 2870 01:52:26,640 --> 01:52:30,880 to find the blue dot in their skies. 2871 01:52:30,880 --> 01:52:33,080 They will marvel at how 2872 01:52:33,080 --> 01:52:34,760 vulnerable the repository of 2873 01:52:34,760 --> 01:52:37,680 all our potential once was, 2874 01:52:37,680 --> 01:52:39,000 how perilous 2875 01:52:39,000 --> 01:52:42,040 our infancy, how humble our 2876 01:52:42,040 --> 01:52:45,640 beginnings, how many rivers we 2877 01:52:45,640 --> 01:52:52,440 had to cross before we found our way. 2878 01:53:18,120 --> 01:53:19,880 If I could travel back into 2879 01:53:19,880 --> 01:53:22,160 time, this is the place I 2880 01:53:22,160 --> 01:53:25,280 would visit, the Library of Alexandria 2881 01:53:25,280 --> 01:53:29,120 at its height 2,000 years ago. 2882 01:53:29,120 --> 01:53:32,000 Here, in an important sense, began 2883 01:53:32,000 --> 01:53:33,800 the intellectual adventure 2884 01:53:33,800 --> 01:53:37,240 which has led us into space. 2885 01:53:37,240 --> 01:53:39,360 All the knowledge in the ancient world 2886 01:53:39,360 --> 01:53:42,680 was once within these marble walls. 2887 01:53:42,680 --> 01:53:44,840 This library was a citadel of 2888 01:53:44,840 --> 01:53:46,480 human consciousness, 2889 01:53:46,480 --> 01:53:50,560 a beacon on our journey to the stars. 2890 01:53:50,560 --> 01:53:52,720 And what did they study? 2891 01:53:52,720 --> 01:53:54,880 They studied everything, the 2892 01:53:54,880 --> 01:53:56,960 entire cosmos. 2893 01:53:56,960 --> 01:53:58,040 But the treasure of the 2894 01:53:58,040 --> 01:54:00,480 library, consecrated to the 2895 01:54:00,480 --> 01:54:02,440 god Serapis, 2896 01:54:02,440 --> 01:54:04,120 built in the city of 2897 01:54:04,120 --> 01:54:07,760 Alexander, was its collection of books. 2898 01:54:07,760 --> 01:54:09,240 Accurate numbers are difficult 2899 01:54:09,240 --> 01:54:10,320 to come by, 2900 01:54:10,320 --> 01:54:11,640 but it seems that the library 2901 01:54:11,640 --> 01:54:14,040 contained at its peak nearly 2902 01:54:14,040 --> 01:54:16,840 one million scrolls. 2903 01:54:16,840 --> 01:54:19,040 What happened to all those books? 2904 01:54:19,040 --> 01:54:19,920 Well, the classical 2905 01:54:19,920 --> 01:54:21,640 civilization that created them 2906 01:54:21,640 --> 01:54:23,240 disintegrated, the library 2907 01:54:23,240 --> 01:54:25,280 itself was destroyed. 2908 01:54:25,280 --> 01:54:27,080 Only a small fraction of the 2909 01:54:27,080 --> 01:54:28,560 works survived. 2910 01:54:28,560 --> 01:54:29,920 And as for the rest, we are 2911 01:54:29,920 --> 01:54:32,200 left only with pathetic, 2912 01:54:32,200 --> 01:54:35,720 scattered fragments. 2913 01:54:35,720 --> 01:54:38,960 Let me tell you about The End. 2914 01:54:38,960 --> 01:54:40,960 It's a story about the last 2915 01:54:40,960 --> 01:54:42,640 scientist to work in this place. 2916 01:54:42,640 --> 01:54:45,200 a mathematician, astronomer, 2917 01:54:45,200 --> 01:54:48,320 physicist, and head of the 2918 01:54:48,320 --> 01:54:49,760 School of Neoplatonic 2919 01:54:49,760 --> 01:54:51,840 Philosophy in Alexandria. 2920 01:54:51,840 --> 01:54:53,360 That's an extraordinary range 2921 01:54:53,360 --> 01:54:54,600 of accomplishments for any 2922 01:54:54,600 --> 01:54:57,120 individual in any age. 2923 01:54:57,120 --> 01:55:00,080 Her name was Hypatia. 2924 01:55:00,080 --> 01:55:02,360 She was born in this city in 2925 01:55:02,360 --> 01:55:07,240 the year 370 A.D. 2926 01:55:07,240 --> 01:55:09,240 This was a time when women 2927 01:55:09,240 --> 01:55:11,120 had essentially no options. 2928 01:55:11,120 --> 01:55:13,640 they were considered property. 2929 01:55:13,640 --> 01:55:15,240 Nevertheless, Hypatia was able 2930 01:55:15,240 --> 01:55:19,400 to move freely, unselfconsciously, 2931 01:55:19,400 --> 01:55:22,320 through traditional male domains. 2932 01:55:23,080 --> 01:55:25,200 By all accounts, she was a 2933 01:55:25,200 --> 01:55:26,520 great beauty. 2934 01:55:26,520 --> 01:55:27,160 And although she had 2935 01:55:27,160 --> 01:55:29,480 many suitors, she had no 2936 01:55:29,480 --> 01:55:32,680 interest in marriage. 2937 01:55:32,680 --> 01:55:34,720 The Alexandria of Hypatia's 2938 01:55:34,720 --> 01:55:36,640 time, by then long under 2939 01:55:36,640 --> 01:55:39,480 Roman rule, was a city in 2940 01:55:39,480 --> 01:55:41,200 grave conflict. 2941 01:55:41,200 --> 01:55:43,880 Slavery, the cancer of the 2942 01:55:43,880 --> 01:55:45,840 ancient world, had sapped classical 2943 01:55:45,840 --> 01:55:49,320 civilization of its vitality. 2944 01:55:49,320 --> 01:55:51,240 The growing Christian Church 2945 01:55:51,240 --> 01:55:53,280 was consolidating its 2946 01:55:53,280 --> 01:55:54,920 power and attempting to 2947 01:55:54,920 --> 01:55:58,840 eradicate pagan influence and culture. 2948 01:55:58,840 --> 01:56:01,080 Hypatia stood at 2949 01:56:01,080 --> 01:56:06,160 the focus, the epicenter of 2950 01:56:06,160 --> 01:56:08,440 mighty social forces. 2951 01:56:08,440 --> 01:56:09,960 Cyril, the bishop of 2952 01:56:09,960 --> 01:56:12,560 Alexandria, despised her, in 2953 01:56:12,560 --> 01:56:13,560 part because of her close 2954 01:56:13,560 --> 01:56:14,600 friendship with the Roman 2955 01:56:14,600 --> 01:56:16,900 governor, but also because she 2956 01:56:16,900 --> 01:56:18,560 was symbolized, she was a 2957 01:56:18,560 --> 01:56:19,960 symbol of learning and 2958 01:56:19,960 --> 01:56:21,960 science, which were largely 2959 01:56:21,960 --> 01:56:23,480 identified by the early church 2960 01:56:23,480 --> 01:56:26,520 with paganism. 2961 01:56:26,520 --> 01:56:28,400 In great personal danger, 2962 01:56:28,400 --> 01:56:30,680 Hypatia continued to teach and 2963 01:56:30,680 --> 01:56:34,120 to publish until, in the year 2964 01:56:34,120 --> 01:56:37,200 415 A.D., on her way to work, 2965 01:56:37,200 --> 01:56:39,640 she was set upon by a 2966 01:56:39,640 --> 01:56:43,240 fanatical mob of Cyril's followers. 2967 01:56:43,240 --> 01:56:44,920 They dragged her from a 2968 01:56:44,920 --> 01:56:47,840 chariot, tore off her clothes, 2969 01:56:47,840 --> 01:56:50,560 and flayed her flesh from her 2970 01:56:50,560 --> 01:56:54,360 bones with abalone shells. 2971 01:56:54,360 --> 01:56:56,160 Her remains were burned, her 2972 01:56:56,160 --> 01:56:58,080 works obliterated, 2973 01:56:58,080 --> 01:56:59,880 her name forgotten. 2974 01:56:59,880 --> 01:57:06,360 Cyril was made a saint. 2975 01:57:06,360 --> 01:57:07,480 The last remains of the 2976 01:57:07,480 --> 01:57:10,080 library were destroyed within 2977 01:57:10,080 --> 01:57:12,240 a year of Hypatia's death. 2978 01:57:12,240 --> 01:57:13,880 It's as if an entire 2979 01:57:13,880 --> 01:57:16,240 civilization had undergone a 2980 01:57:16,240 --> 01:57:18,960 sort of self-inflicted radical 2981 01:57:18,960 --> 01:57:20,600 brain surgery, 2982 01:57:20,600 --> 01:57:23,040 so that most of its memories, 2983 01:57:23,040 --> 01:57:25,120 discoveries, ideas, and 2984 01:57:25,120 --> 01:57:34,920 passions were irrevocably wiped out. 2985 01:57:34,920 --> 01:57:38,280 History is full of people 2986 01:57:38,280 --> 01:57:41,560 who, out of fear or ignorance 2987 01:57:41,560 --> 01:57:44,840 or a lust for power, have destroyed 2988 01:57:44,840 --> 01:57:48,200 treasures of immeasurable value 2989 01:57:48,200 --> 01:57:52,240 which truly belong to all of us. 2990 01:57:52,240 --> 01:57:56,920 We must not let it happen again. 2991 01:57:56,920 --> 01:57:58,720 We were, at long last, 2992 01:57:58,720 --> 01:58:00,320 beginning to find our true 2993 01:58:00,320 --> 01:58:03,520 bearings in the cosmos. 2994 01:58:03,520 --> 01:58:05,360 The scientists of antiquity 2995 01:58:05,360 --> 01:58:06,960 took the first and most 2996 01:58:06,960 --> 01:58:09,160 important steps in that direction 2997 01:58:09,160 --> 01:58:12,440 before their civilization fell apart. 2998 01:58:12,440 --> 01:58:14,480 But after the Dark Ages, it 2999 01:58:14,480 --> 01:58:15,640 was by and large the 3000 01:58:15,640 --> 01:58:17,480 rediscovery of the works of 3001 01:58:17,480 --> 01:58:18,360 these scholars 3002 01:58:18,360 --> 01:58:20,120 done here that made the 3003 01:58:20,120 --> 01:58:22,160 Renaissance possible and 3004 01:58:22,160 --> 01:58:23,680 thereby powerfully influenced 3005 01:58:23,680 --> 01:58:25,360 our own culture. 3006 01:58:25,360 --> 01:58:26,960 When in the 15th century 3007 01:58:26,960 --> 01:58:29,280 Europe was at last ready to 3008 01:58:29,280 --> 01:58:31,800 awaken from its long sleep, 3009 01:58:31,800 --> 01:58:33,160 it picked up some of the 3010 01:58:33,160 --> 01:58:35,200 tools, the books and the 3011 01:58:35,200 --> 01:58:38,160 concepts laid down here more 3012 01:58:38,160 --> 01:58:45,760 than a thousand years before. 3013 01:58:45,760 --> 01:58:48,160 By 1600, the long-forgotten 3014 01:58:48,160 --> 01:58:50,000 ideas of Aristarchus had 3015 01:58:50,000 --> 01:58:52,160 been rediscovered. 3016 01:58:52,160 --> 01:58:54,640 Johannes Kepler constructed 3017 01:58:54,640 --> 01:58:56,240 elaborate models to understand 3018 01:58:56,240 --> 01:58:57,680 the motion and arrangement of 3019 01:58:57,680 --> 01:58:58,760 the planets, 3020 01:58:58,760 --> 01:59:04,560 the clockwork of the heavens. 3021 01:59:04,560 --> 01:59:06,800 His principal scientific tools 3022 01:59:06,800 --> 01:59:08,120 were the mathematics of the 3023 01:59:08,120 --> 01:59:09,920 Alexandrian library 3024 01:59:09,920 --> 01:59:11,640 and an unswerving respect for 3025 01:59:11,640 --> 01:59:12,760 the facts, 3026 01:59:12,760 --> 01:59:18,160 however disquieting they might be. 3027 01:59:18,160 --> 01:59:19,720 Seventy years later, 3028 01:59:19,720 --> 01:59:21,240 the Sun-centered universe of 3029 01:59:21,240 --> 01:59:23,320 Aristarchus and Copernicus 3030 01:59:23,320 --> 01:59:25,080 was widely accepted in the 3031 01:59:25,080 --> 01:59:27,000 Europe of the Enlightenment. 3032 01:59:27,000 --> 01:59:29,080 The idea arose that the 3033 01:59:29,080 --> 01:59:31,440 planets were worlds, governed 3034 01:59:31,440 --> 01:59:32,840 by laws of nature, 3035 01:59:32,840 --> 01:59:34,200 and scientific speculation 3036 01:59:34,200 --> 01:59:37,240 turned to the motions of the stars. 3037 01:59:37,240 --> 01:59:39,000 The clockwork in the heavens 3038 01:59:39,000 --> 01:59:40,440 was imitated by the 3039 01:59:40,440 --> 01:59:42,520 watchmakers of Earth. 3040 01:59:42,520 --> 01:59:44,200 Precise timekeeping permitted 3041 01:59:44,200 --> 01:59:46,440 great sailing ship voyages of 3042 01:59:46,440 --> 01:59:48,280 exploration and discovery, 3043 01:59:48,280 --> 01:59:52,040 which bound up the Earth. 3044 01:59:52,600 --> 01:59:54,400 This was a time when free 3045 01:59:54,400 --> 01:59:59,000 inquiry was valued once again. 3046 01:59:59,000 --> 02:00:01,080 250 years later, the Earth 3047 02:00:01,080 --> 02:00:02,600 was all explored. 3048 02:00:02,600 --> 02:00:04,400 New adventurers now looked to 3049 02:00:04,400 --> 02:00:06,720 the planets and the stars. 3050 02:00:06,720 --> 02:00:08,400 Galaxies were recognized as 3051 02:00:08,400 --> 02:00:10,400 great aggregates of stars, 3052 02:00:10,400 --> 02:00:13,320 island universes, millions of 3053 02:00:13,320 --> 02:00:15,120 light years away. 3054 02:00:15,120 --> 02:00:17,440 In the 1920s, astronomers had 3055 02:00:17,440 --> 02:00:19,440 begun to measure the speeds 3056 02:00:19,440 --> 02:00:21,600 of distant galaxies. 3057 02:00:21,600 --> 02:00:23,760 They found that the galaxies 3058 02:00:23,760 --> 02:00:26,440 were flying away from one another. 3059 02:00:26,440 --> 02:00:27,640 To the astonishment of 3060 02:00:27,640 --> 02:00:30,200 everyone, the entire universe 3061 02:00:30,200 --> 02:00:32,080 was expanding. 3062 02:00:32,080 --> 02:00:33,920 We had begun to plumb the 3063 02:00:33,920 --> 02:00:37,680 true depths of time and space. 3064 02:00:37,680 --> 02:00:39,440 The long collective enterprise 3065 02:00:39,440 --> 02:00:41,320 of science has revealed a 3066 02:00:41,320 --> 02:00:46,120 universe some 15 billion years old. 3067 02:00:46,120 --> 02:00:47,680 We on Earth have just 3068 02:00:47,680 --> 02:00:50,080 awakened to the great oceans 3069 02:00:50,080 --> 02:00:52,200 of space and time from which 3070 02:00:52,200 --> 02:00:54,040 we have emerged. 3071 02:00:54,040 --> 02:00:56,760 We are the legacy of 15 3072 02:00:56,760 --> 02:00:59,800 billion years of cosmic evolution. 3073 02:00:59,800 --> 02:01:01,800 We have a choice. 3074 02:01:01,800 --> 02:01:03,360 We can enhance life and come 3075 02:01:03,360 --> 02:01:04,360 to know the universe that 3076 02:01:04,360 --> 02:01:06,560 made us, or we can squander 3077 02:01:06,560 --> 02:01:07,560 our 15 billion 3078 02:01:07,560 --> 02:01:09,160 year heritage in 3079 02:01:09,160 --> 02:01:13,120 meaningless self-destruction. 3080 02:01:13,120 --> 02:01:14,240 What happens in the first 3081 02:01:14,240 --> 02:01:15,640 second of the next cosmic 3082 02:01:15,640 --> 02:01:19,160 year depends on what we do here and 3083 02:01:19,160 --> 02:01:22,080 now with our intelligence and 3084 02:01:22,080 --> 02:01:49,560 our knowledge of the cosmos. 3085 02:01:49,560 --> 02:01:51,960 This is the age of planetary 3086 02:01:51,960 --> 02:01:54,240 exploration, when our ships 3087 02:01:54,240 --> 02:01:58,280 have begun to sail the heavens. 3088 02:01:58,280 --> 02:01:59,440 In those heavens there are 3089 02:01:59,440 --> 02:02:02,040 some worlds much like hell. 3090 02:02:02,040 --> 02:02:04,480 Our planet is, in comparison, 3091 02:02:04,480 --> 02:02:06,120 much like a heaven. 3092 02:02:06,120 --> 02:02:07,720 But the gates of heaven and 3093 02:02:07,720 --> 02:02:13,200 hell are adjacent and unmarked. 3094 02:02:13,200 --> 02:02:14,600 We've evolved on the planet 3095 02:02:14,600 --> 02:02:16,400 Earth, and so we find it a 3096 02:02:16,400 --> 02:02:18,000 congenial place. 3097 02:02:18,000 --> 02:02:20,520 But just next door is Venus, 3098 02:02:20,520 --> 02:02:23,720 until recently enveloped in mystery. 3099 02:02:23,720 --> 02:02:24,960 It has almost the same size 3100 02:02:24,960 --> 02:02:26,920 and mass as the Earth. 3101 02:02:26,920 --> 02:02:28,920 Might our sister world be a 3102 02:02:28,920 --> 02:02:31,000 balmy summer planet, 3103 02:02:31,000 --> 02:02:31,960 A little warmer than the 3104 02:02:31,960 --> 02:02:32,920 Earth because it's a little 3105 02:02:32,920 --> 02:02:34,480 closer to the Sun? 3106 02:02:34,480 --> 02:02:36,320 Are there craters, volcanoes, 3107 02:02:36,320 --> 02:02:39,680 mountains, oceans, life? 3108 02:02:39,680 --> 02:02:41,360 From a distance, our sister 3109 02:02:41,360 --> 02:02:43,400 planet seems serene and 3110 02:02:43,400 --> 02:02:46,840 peaceful, its clouds motionless. 3111 02:02:46,840 --> 02:02:48,600 These clouds are near the top 3112 02:02:48,600 --> 02:02:50,440 of a great ocean of air, 3113 02:02:50,440 --> 02:02:51,920 about a hundred kilometers 3114 02:02:51,920 --> 02:02:53,040 thick, composed 3115 02:02:53,040 --> 02:02:56,120 mainly of carbon dioxide. 3116 02:02:56,120 --> 02:02:57,560 There's some nitrogen, a 3117 02:02:57,560 --> 02:02:58,800 little water vapor and other 3118 02:02:58,800 --> 02:03:00,680 gases, but only the merest 3119 02:03:00,680 --> 02:03:03,040 trace of hydrocarbons. 3120 02:03:03,040 --> 02:03:04,160 And the clouds turn out to 3121 02:03:04,160 --> 02:03:06,160 be not water, but a 3122 02:03:06,160 --> 02:03:07,600 concentrated solution 3123 02:03:07,600 --> 02:03:10,400 of sulfuric acid. 3124 02:03:10,400 --> 02:03:12,320 Even in the high clouds, 3125 02:03:12,320 --> 02:03:16,840 Venus is a thoroughly nasty place. 3126 02:03:16,840 --> 02:03:17,360 The clouds 3127 02:03:17,360 --> 02:03:19,680 are stained yellow by sulfur. 3128 02:03:19,680 --> 02:03:21,800 There are great lightning storms. 3129 02:03:21,800 --> 02:03:23,320 As we descend, there are 3130 02:03:23,320 --> 02:03:24,400 increasing amounts of the 3131 02:03:24,400 --> 02:03:26,840 noxious gas sulfur dioxide. 3132 02:03:26,840 --> 02:03:28,960 The pressures become so high that 3133 02:03:28,960 --> 02:03:30,240 The early Venera spacecraft 3134 02:03:30,240 --> 02:03:32,080 were crushed like old tin 3135 02:03:32,080 --> 02:03:33,720 cans by the weight of the 3136 02:03:33,720 --> 02:03:37,080 surrounding atmosphere. 3137 02:03:37,080 --> 02:03:38,760 Beneath the clouds, in the 3138 02:03:38,760 --> 02:03:40,680 dense, clear air, it's about 3139 02:03:40,680 --> 02:03:42,080 as bright as on an overcast day 3140 02:03:42,080 --> 02:03:43,720 on Earth, but the atmosphere 3141 02:03:43,720 --> 02:03:44,960 is so thick that the ground 3142 02:03:44,960 --> 02:03:48,640 seems to ripple and distort. 3143 02:03:48,640 --> 02:03:50,000 The atmospheric pressure down 3144 02:03:50,000 --> 02:03:52,640 here is 90 times that on Earth. 3145 02:03:52,640 --> 02:03:55,200 The temperature is 380 degrees 3146 02:03:55,200 --> 02:03:58,200 centigrade, 900 Fahrenheit, 3147 02:03:58,200 --> 02:04:01,080 hotter than the hottest household oven. 3148 02:04:01,080 --> 02:04:02,440 This is a world marked by 3149 02:04:02,440 --> 02:04:04,440 searing heat, crushing 3150 02:04:04,440 --> 02:04:06,640 pressures, sulfurous gases in 3151 02:04:06,640 --> 02:04:09,480 a desolate, reddish landscape. 3152 02:04:09,480 --> 02:04:11,360 Far from the balmy paradise 3153 02:04:11,360 --> 02:04:12,480 imagined by some early 3154 02:04:12,480 --> 02:04:14,560 scientists, Venus is the one 3155 02:04:14,560 --> 02:04:16,320 place in the solar system 3156 02:04:16,320 --> 02:04:19,160 most like hell. 3157 02:04:19,160 --> 02:04:20,800 But today, as in ancient 3158 02:04:20,800 --> 02:04:22,840 tradition, there are travelers 3159 02:04:22,840 --> 02:04:24,880 who will dare a visit to 3160 02:04:24,880 --> 02:04:26,560 the underworld. 3161 02:04:26,560 --> 02:04:28,200 Venera 9 was the first 3162 02:04:28,200 --> 02:04:29,880 spacecraft in human history to 3163 02:04:29,880 --> 02:04:30,960 return a photograph from the 3164 02:04:30,960 --> 02:04:32,600 surface of Venus. 3165 02:04:32,600 --> 02:04:34,760 It found the rocks curiously 3166 02:04:34,760 --> 02:04:36,440 eroded, perhaps by the 3167 02:04:36,440 --> 02:04:38,520 corrosive gases, perhaps because the 3168 02:04:38,520 --> 02:04:39,800 temperature is so high that 3169 02:04:39,800 --> 02:04:41,280 the rocks are partly molten 3170 02:04:41,280 --> 02:04:44,120 and sluggishly flow. 3171 02:04:44,120 --> 02:04:46,560 The Soviet Venera spacecraft, 3172 02:04:46,560 --> 02:04:48,160 their electronics long ago 3173 02:04:48,160 --> 02:04:50,960 fried, are slowly corroding on the 3174 02:04:50,960 --> 02:04:51,640 surface of Venus. 3175 02:04:52,720 --> 02:04:54,080 They are the first spaceships 3176 02:04:54,080 --> 02:04:56,320 from Earth ever to land on 3177 02:04:56,320 --> 02:04:59,160 another planet. 3178 02:04:59,160 --> 02:05:01,240 The reason Venus is like hell 3179 02:05:01,240 --> 02:05:02,720 seems to be what's called the 3180 02:05:02,720 --> 02:05:04,480 greenhouse effect. 3181 02:05:04,480 --> 02:05:06,040 Ordinary visible sunlight 3182 02:05:06,040 --> 02:05:07,120 penetrates the clouds and 3183 02:05:07,120 --> 02:05:08,800 heats the surface, but the 3184 02:05:08,800 --> 02:05:09,800 dense atmosphere 3185 02:05:09,800 --> 02:05:11,600 blankets the surface and 3186 02:05:11,600 --> 02:05:12,840 prevents it from cooling off 3187 02:05:12,840 --> 02:05:14,240 into space. 3188 02:05:14,240 --> 02:05:15,960 An atmosphere 90 times as 3189 02:05:15,960 --> 02:05:17,800 dense as ours, made of carbon 3190 02:05:17,800 --> 02:05:20,040 dioxide, water vapor and other gases, 3191 02:05:20,040 --> 02:05:21,120 lets in visible light from 3192 02:05:21,120 --> 02:05:22,920 the Sun, but will not let 3193 02:05:22,920 --> 02:05:24,520 out the infrared light 3194 02:05:24,520 --> 02:05:26,400 radiated by the surface. 3195 02:05:26,400 --> 02:05:28,160 So the temperature rises until 3196 02:05:28,160 --> 02:05:29,200 the infrared radiation 3197 02:05:29,200 --> 02:05:32,080 trickling out to space just balances 3198 02:05:32,080 --> 02:05:35,400 the Sunlight reaching the surface. 3199 02:05:35,400 --> 02:05:37,160 The greenhouse effect can make 3200 02:05:37,160 --> 02:05:39,000 an Earth-like world into a 3201 02:05:39,000 --> 02:05:42,120 planetary inferno. 3202 02:05:42,120 --> 02:05:43,600 In this cauldron, there is 3203 02:05:43,600 --> 02:05:44,680 not likely to be anything 3204 02:05:44,680 --> 02:05:46,480 alive, even creatures very 3205 02:05:46,480 --> 02:05:47,760 different from us. 3206 02:05:47,760 --> 02:05:49,560 Organic and other conceivable 3207 02:05:49,560 --> 02:05:51,240 biological molecules would 3208 02:05:51,240 --> 02:05:54,080 simply fall to pieces. 3209 02:05:54,080 --> 02:05:55,760 The hell of Venus is in 3210 02:05:55,760 --> 02:05:57,360 stark contrast with the 3211 02:05:57,360 --> 02:05:59,200 comparative heaven of its 3212 02:05:59,200 --> 02:06:00,640 neighboring world, 3213 02:06:00,640 --> 02:06:05,920 our little planetary home, the Earth. 3214 02:06:05,920 --> 02:06:08,520 Here, the atmosphere is 90 3215 02:06:08,520 --> 02:06:10,040 times thinner. 3216 02:06:10,040 --> 02:06:12,040 Here, the carbon dioxide and 3217 02:06:12,040 --> 02:06:13,920 water vapor make a modest 3218 02:06:13,920 --> 02:06:15,960 greenhouse effect, which heats the 3219 02:06:15,960 --> 02:06:17,120 ground above the freezing 3220 02:06:17,120 --> 02:06:18,560 point of water. 3221 02:06:18,560 --> 02:06:20,680 Without it, our oceans would 3222 02:06:20,680 --> 02:06:23,160 be frozen solid. 3223 02:06:23,160 --> 02:06:25,120 A little greenhouse effect is 3224 02:06:25,120 --> 02:06:27,120 a good thing. 3225 02:06:27,120 --> 02:06:28,800 But Venus is an ominous 3226 02:06:28,800 --> 02:06:30,760 reminder that on a world 3227 02:06:30,760 --> 02:06:33,440 rather like the Earth, things 3228 02:06:33,440 --> 02:06:35,200 can go wrong. 3229 02:06:35,200 --> 02:06:36,400 There is no guarantee that 3230 02:06:36,400 --> 02:06:37,680 our planet will always be 3231 02:06:37,680 --> 02:06:39,920 so hospitable. 3232 02:06:39,920 --> 02:06:41,440 To maintain this clement 3233 02:06:41,440 --> 02:06:44,200 world, we must understand it 3234 02:06:44,200 --> 02:06:46,600 and appreciate it. 3235 02:06:46,600 --> 02:06:48,640 The Earth is a place to our 3236 02:06:48,640 --> 02:06:51,040 eyes more beautiful than any 3237 02:06:51,040 --> 02:06:52,920 other that we know. 3238 02:06:52,920 --> 02:06:54,800 The destruction of trees and 3239 02:06:54,800 --> 02:06:56,880 grasslands makes the surface 3240 02:06:56,880 --> 02:06:58,800 of the Earth brighter. 3241 02:06:58,800 --> 02:07:00,400 It reflects more sunlight back 3242 02:07:00,400 --> 02:07:02,860 to space and cools our planet. 3243 02:07:02,860 --> 02:07:05,800 But after we discovered fire, 3244 02:07:05,800 --> 02:07:08,400 we began to incinerate forests 3245 02:07:08,400 --> 02:07:09,520 intentionally to clear 3246 02:07:09,520 --> 02:07:11,680 the land by a process called 3247 02:07:11,680 --> 02:07:14,880 slash-and-burn agriculture. 3248 02:07:14,880 --> 02:07:17,000 And today, forests and 3249 02:07:17,000 --> 02:07:19,840 grasslands are being destroyed 3250 02:07:19,840 --> 02:07:23,760 frivolously, carelessly, by humans 3251 02:07:23,760 --> 02:07:25,120 who are heedless of the 3252 02:07:25,120 --> 02:07:27,240 beauty of our cousins, the 3253 02:07:27,240 --> 02:07:29,680 trees, and ignorant of the 3254 02:07:29,680 --> 02:07:30,720 possible climatic 3255 02:07:30,720 --> 02:07:33,240 catastrophes which large-scale 3256 02:07:33,240 --> 02:07:37,640 burning of forests may bring. 3257 02:07:37,640 --> 02:07:39,000 The indiscriminate destruction 3258 02:07:39,000 --> 02:07:40,920 of vegetation may alter the 3259 02:07:40,920 --> 02:07:42,840 global climate in ways that 3260 02:07:42,840 --> 02:07:46,640 no scientist can yet predict. 3261 02:07:46,640 --> 02:07:48,480 It has already deadened large 3262 02:07:48,480 --> 02:07:49,640 patches of the Earth's 3263 02:07:49,640 --> 02:07:51,440 life-supporting skin. 3264 02:07:52,480 --> 02:07:54,720 And yet we ravage the Earth 3265 02:07:54,720 --> 02:07:57,200 at an accelerated pace, as if 3266 02:07:57,200 --> 02:07:59,520 it belonged to this one generation, 3267 02:07:59,520 --> 02:08:01,120 as if it were ours to do 3268 02:08:01,120 --> 02:08:03,560 with as we please. 3269 02:08:03,560 --> 02:08:04,920 The Earth has mechanisms to 3270 02:08:04,920 --> 02:08:06,120 cleanse itself, 3271 02:08:06,120 --> 02:08:07,640 to neutralize the toxic 3272 02:08:07,640 --> 02:08:09,680 substances in its system. 3273 02:08:09,680 --> 02:08:11,040 But these mechanisms work only 3274 02:08:11,040 --> 02:08:12,360 up to a point. 3275 02:08:12,360 --> 02:08:14,640 Beyond some critical threshold, 3276 02:08:14,640 --> 02:08:16,120 they break down. 3277 02:08:16,120 --> 02:08:20,560 The damage becomes irreversible. 3278 02:08:20,560 --> 02:08:22,720 Our generation must choose. 3279 02:08:22,720 --> 02:08:24,320 Which do we value more, 3280 02:08:24,320 --> 02:08:25,960 short-term profits 3281 02:08:25,960 --> 02:08:28,080 or the long-term habitability 3282 02:08:28,080 --> 02:08:31,080 of our planetary home? 3283 02:08:31,080 --> 02:08:32,080 The world is divided 3284 02:08:32,080 --> 02:08:34,000 politically, but ecologically 3285 02:08:34,000 --> 02:08:35,840 it is tightly interwoven. 3286 02:08:35,840 --> 02:08:37,400 There are no useless threads 3287 02:08:37,400 --> 02:08:39,800 in the fabric of the ecosystem. 3288 02:08:39,800 --> 02:08:41,160 If you cut any one of them, 3289 02:08:41,160 --> 02:08:44,320 you will unravel many others. 3290 02:08:44,320 --> 02:08:45,800 We have uncovered other worlds 3291 02:08:45,800 --> 02:08:48,000 with choking atmospheres and 3292 02:08:48,000 --> 02:08:49,640 deadly surfaces. 3293 02:08:49,640 --> 02:08:51,200 Shall we then recreate these 3294 02:08:51,200 --> 02:08:55,640 hells on Earth? 3295 02:08:55,640 --> 02:08:56,920 We have encountered desolate 3296 02:08:56,920 --> 02:08:59,800 moons and barren asteroids. 3297 02:08:59,800 --> 02:09:02,040 Shall we then scar and crater 3298 02:09:02,040 --> 02:09:05,760 this blooming world in their likeness? 3299 02:09:05,760 --> 02:09:08,640 Natural catastrophes are rare, 3300 02:09:08,640 --> 02:09:10,360 but they come often enough. 3301 02:09:10,360 --> 02:09:14,120 We need not force the hand of nature. 3302 02:09:14,120 --> 02:09:16,080 If we ruin the Earth, there 3303 02:09:16,080 --> 02:09:18,600 is no place else to go. 3304 02:09:18,600 --> 02:09:20,360 This is not a disposable 3305 02:09:20,360 --> 02:09:22,160 world, and we are not yet 3306 02:09:22,160 --> 02:09:25,920 able to re-engineer the planets. 3307 02:09:25,920 --> 02:09:28,600 The cruelest desert on Earth 3308 02:09:28,600 --> 02:09:31,120 is far more hospitable than 3309 02:09:31,120 --> 02:09:34,200 any place on Mars. 3310 02:09:34,200 --> 02:09:35,960 The bright sandy surface and 3311 02:09:35,960 --> 02:09:37,800 dusty atmosphere of Mars 3312 02:09:37,800 --> 02:09:39,000 reflect enough sunlight back 3313 02:09:39,000 --> 02:09:41,560 to space to cool the planet, 3314 02:09:41,560 --> 02:09:43,440 freezing out all its water, 3315 02:09:43,440 --> 02:09:47,720 locking it in a perpetual ice age. 3316 02:09:47,720 --> 02:09:49,960 Human activities brighten our 3317 02:09:49,960 --> 02:09:52,400 landscape and our atmosphere. 3318 02:09:52,400 --> 02:09:53,880 Might this ultimately make an 3319 02:09:53,880 --> 02:09:56,760 ice age here? 3320 02:09:56,760 --> 02:09:57,920 At the same time, we are 3321 02:09:57,920 --> 02:09:59,600 releasing vast quantities of 3322 02:09:59,600 --> 02:10:02,040 carbon dioxide, increasing the 3323 02:10:02,040 --> 02:10:03,840 greenhouse effect. 3324 02:10:03,840 --> 02:10:05,080 The Earth need not resemble 3325 02:10:05,080 --> 02:10:07,120 Venus very closely for it to 3326 02:10:07,120 --> 02:10:11,600 become barren and lifeless. 3327 02:10:11,600 --> 02:10:12,880 It may not take much to 3328 02:10:12,880 --> 02:10:15,120 destabilize the Earth's climate, 3329 02:10:15,120 --> 02:10:17,000 to convert this heaven, our 3330 02:10:17,000 --> 02:10:19,080 only home in the cosmos, into 3331 02:10:19,080 --> 02:10:21,320 a kind of hell. 3332 02:10:23,280 --> 02:10:24,440 The study of the global 3333 02:10:24,440 --> 02:10:27,360 climate, the Sun's influence, 3334 02:10:27,360 --> 02:10:28,480 the comparison of the Earth 3335 02:10:28,480 --> 02:10:30,520 with other worlds, these are 3336 02:10:30,520 --> 02:10:31,280 subjects in their 3337 02:10:31,280 --> 02:10:33,760 earliest stages of development. 3338 02:10:33,760 --> 02:10:35,800 They are funded poorly and 3339 02:10:35,800 --> 02:10:37,360 grudgingly, and 3340 02:10:37,360 --> 02:10:39,040 meanwhile we continue to load 3341 02:10:39,040 --> 02:10:40,320 the Earth's atmosphere with 3342 02:10:40,320 --> 02:10:41,680 materials about 3343 02:10:41,680 --> 02:10:43,040 whose long-term influence we 3344 02:10:43,040 --> 02:10:47,400 are almost entirely ignorant. 3345 02:10:47,400 --> 02:10:49,080 There are worlds that 3346 02:10:49,080 --> 02:10:50,560 began with as much apparent 3347 02:10:50,560 --> 02:10:52,480 promise as Earth, but 3348 02:10:52,480 --> 02:10:55,480 something went wrong. Knowing 3349 02:10:55,480 --> 02:10:58,360 that worlds can die alerts us 3350 02:10:58,360 --> 02:11:00,840 to our danger. 3351 02:11:00,840 --> 02:11:02,120 If a visitor arrived from 3352 02:11:02,120 --> 02:11:03,480 another world, what 3353 02:11:03,480 --> 02:11:05,280 account would we give of our 3354 02:11:05,280 --> 02:11:13,720 stewardship of the planet Earth? 3355 02:11:13,720 --> 02:11:15,760 Spaceflight speaks to something 3356 02:11:15,760 --> 02:11:20,560 deep inside us, many of us, if not all. 3357 02:11:20,560 --> 02:11:22,080 An emerging cosmic 3358 02:11:22,080 --> 02:11:24,440 perspective, an improved 3359 02:11:24,440 --> 02:11:25,320 understanding of our place in 3360 02:11:25,320 --> 02:11:28,000 the universe, a highly visible 3361 02:11:28,000 --> 02:11:29,320 program affecting our view of 3362 02:11:29,320 --> 02:11:32,240 ourselves, might clarify the 3363 02:11:32,240 --> 02:11:35,440 fragility of our planetary environment 3364 02:11:35,440 --> 02:11:37,280 and the common peril and 3365 02:11:37,280 --> 02:11:39,040 responsibility of all the 3366 02:11:39,040 --> 02:11:43,080 nations and peoples of Earth. 3367 02:11:43,080 --> 02:11:44,480 And human missions to Mars 3368 02:11:44,480 --> 02:11:46,480 would provide hopeful 3369 02:11:46,480 --> 02:11:48,600 prospects, rich in adventure, 3370 02:11:48,600 --> 02:11:49,600 for the wanderers 3371 02:11:49,600 --> 02:11:53,000 among us, especially the young. 3372 02:11:53,000 --> 02:11:55,400 Even vicarious exploration has 3373 02:11:55,400 --> 02:11:58,440 social utility. 3374 02:11:58,440 --> 02:12:00,480 It's no accident that whatever 3375 02:12:00,480 --> 02:12:04,440 their human flaws, and however 3376 02:12:04,440 --> 02:12:06,000 moribund the human space 3377 02:12:06,000 --> 02:12:09,880 program has become, astronauts 3378 02:12:09,880 --> 02:12:11,960 and cosmonauts are still 3379 02:12:11,960 --> 02:12:13,560 widely regarded as heroes of 3380 02:12:13,560 --> 02:12:16,120 our species. 3381 02:12:16,120 --> 02:12:17,320 A scientific colleague tells 3382 02:12:17,320 --> 02:12:18,360 me about a recent trip to 3383 02:12:18,360 --> 02:12:20,600 the New Guinea highlands, where she 3384 02:12:20,600 --> 02:12:22,760 visited a Stone Age culture 3385 02:12:22,760 --> 02:12:23,920 hardly contacted by 3386 02:12:23,920 --> 02:12:26,360 Western civilization. 3387 02:12:26,360 --> 02:12:27,960 They were ignorant of 3388 02:12:27,960 --> 02:12:29,960 wristwatches, soft drinks, 3389 02:12:29,960 --> 02:12:32,360 frozen food, but they knew 3390 02:12:32,360 --> 02:12:34,480 about Apollo 11. 3391 02:12:34,480 --> 02:12:36,240 They knew that humans had 3392 02:12:36,240 --> 02:12:38,240 walked on the Moon. 3393 02:12:38,240 --> 02:12:39,120 They knew the names of 3394 02:12:39,120 --> 02:12:43,200 Armstrong and Aldrin and Collins. 3395 02:12:43,200 --> 02:12:44,920 They wanted to know who was 3396 02:12:44,920 --> 02:12:49,960 visiting the Moon these days. 3397 02:12:49,960 --> 02:12:51,320 Winning a foothold on other 3398 02:12:51,320 --> 02:12:54,920 worlds whispers in our ears 3399 02:12:54,920 --> 02:12:57,560 that we're more than Picts, 3400 02:12:57,560 --> 02:13:04,600 or Serbs, or Tongans. We're humans. 3401 02:13:04,600 --> 02:13:07,720 Exploratory spaceflight puts 3402 02:13:07,720 --> 02:13:10,080 scientific ideas, scientific 3403 02:13:10,080 --> 02:13:11,840 thinking, and scientific 3404 02:13:11,840 --> 02:13:15,280 vocabulary in the public eye. 3405 02:13:15,280 --> 02:13:17,360 It elevates the general level 3406 02:13:17,360 --> 02:13:20,360 of intellectual inquiry. 3407 02:13:20,360 --> 02:13:22,080 The idea that we've now 3408 02:13:22,080 --> 02:13:23,720 understood something never 3409 02:13:23,720 --> 02:13:25,720 grasped by anybody who ever 3410 02:13:25,720 --> 02:13:28,000 lived before, 3411 02:13:28,000 --> 02:13:30,520 that exhilaration, especially 3412 02:13:30,520 --> 02:13:31,560 intense for the scientists 3413 02:13:31,560 --> 02:13:33,240 involved but perceptible to 3414 02:13:33,240 --> 02:13:36,600 nearly everybody, propagates 3415 02:13:36,600 --> 02:13:38,280 through the society, bounces 3416 02:13:38,280 --> 02:13:41,760 off walls, and comes back at us. 3417 02:13:41,760 --> 02:13:43,440 It encourages us to address 3418 02:13:43,440 --> 02:13:45,960 problems in other fields that 3419 02:13:45,960 --> 02:13:48,600 have also never been solved. 3420 02:13:48,600 --> 02:13:49,960 It increases the general sense 3421 02:13:49,960 --> 02:13:52,600 of optimism in the society. 3422 02:13:52,600 --> 02:13:54,080 It gives currency to critical 3423 02:13:54,080 --> 02:13:56,280 thinking of the sort urgently 3424 02:13:56,280 --> 02:13:58,320 needed if we're going to 3425 02:13:58,320 --> 02:14:00,440 solve hitherto intractable 3426 02:14:00,440 --> 02:14:02,640 social issues. 3427 02:14:02,640 --> 02:14:03,800 It helps stimulate a new 3428 02:14:03,800 --> 02:14:06,240 generation of scientists. 3429 02:14:06,240 --> 02:14:07,320 The more science in the 3430 02:14:07,320 --> 02:14:09,560 media, the healthier, I 3431 02:14:09,560 --> 02:14:11,420 believe, the society is. 3432 02:14:11,420 --> 02:14:14,800 Just people everywhere, hunger 3433 02:14:14,800 --> 02:14:17,680 to understand. 3434 02:14:17,680 --> 02:14:19,920 When I was a child, my most 3435 02:14:19,920 --> 02:14:23,640 exultant dreams were about flying. 3436 02:14:23,640 --> 02:14:28,240 Not in some machine, but all by myself. 3437 02:14:28,240 --> 02:14:31,360 I'd be skipping or hopping, 3438 02:14:31,360 --> 02:14:33,240 and slowly I could pull my 3439 02:14:33,240 --> 02:14:35,240 trajectory higher. 3440 02:14:35,240 --> 02:14:36,320 It would take longer to fall 3441 02:14:36,320 --> 02:14:37,320 back to the ground. 3442 02:14:37,320 --> 02:14:39,880 and soon I'd be on such a 3443 02:14:39,880 --> 02:14:42,120 high arc that I wouldn't come 3444 02:14:42,120 --> 02:14:44,760 down at all. 3445 02:14:44,760 --> 02:14:46,560 I would alight like a 3446 02:14:46,560 --> 02:14:48,600 gargoyle in a niche near the 3447 02:14:48,600 --> 02:14:52,080 pinnacle of a skyscraper, or I'd 3448 02:14:52,080 --> 02:14:55,200 gently settle down on a cloud. 3449 02:14:55,200 --> 02:14:56,960 In the dream, which I must 3450 02:14:56,960 --> 02:14:58,080 have had in its many 3451 02:14:58,080 --> 02:15:02,040 variations at least a hundred times, 3452 02:15:02,040 --> 02:15:03,520 achieving flight required a 3453 02:15:03,520 --> 02:15:06,440 certain cast of mind. 3454 02:15:06,440 --> 02:15:07,840 It's impossible to describe it 3455 02:15:07,840 --> 02:15:10,200 in words, but I can remember 3456 02:15:10,200 --> 02:15:13,000 what it was like, to this day. 3457 02:15:13,000 --> 02:15:14,280 You did something inside your 3458 02:15:14,280 --> 02:15:15,960 head and at the pit of your 3459 02:15:15,960 --> 02:15:19,000 stomach, and then you could lift 3460 02:15:19,000 --> 02:15:21,000 yourself up by an effort of 3461 02:15:21,000 --> 02:15:23,960 will alone, your limbs hanging 3462 02:15:23,960 --> 02:15:29,120 limply, off you'd soar. 3463 02:15:29,120 --> 02:15:30,200 I know many people have had 3464 02:15:30,200 --> 02:15:32,440 similar dreams, maybe most 3465 02:15:32,440 --> 02:15:35,800 people, maybe everyone. 3466 02:15:35,800 --> 02:15:37,240 Perhaps it goes back 10 3467 02:15:37,240 --> 02:15:39,000 million years or more, when 3468 02:15:39,000 --> 02:15:41,320 our ancestors were gracefully 3469 02:15:41,320 --> 02:15:43,360 flinging themselves from branch 3470 02:15:43,360 --> 02:15:46,560 to branch in the primeval forest. 3471 02:15:46,560 --> 02:15:47,920 A wish to soar like the 3472 02:15:47,920 --> 02:15:49,760 birds motivated many of the 3473 02:15:49,760 --> 02:15:51,640 pioneers of flight, including 3474 02:15:51,640 --> 02:15:53,560 Leonardo da Vinci and the 3475 02:15:53,560 --> 02:15:55,320 Wright brothers. 3476 02:15:55,320 --> 02:15:56,800 Maybe that's part of the 3477 02:15:56,800 --> 02:16:00,200 appeal of spaceflight too. 3478 02:16:00,200 --> 02:16:03,120 In orbit around any world, or 3479 02:16:03,120 --> 02:16:04,560 in interplanetary flight, 3480 02:16:04,560 --> 02:16:06,520 you're literally weightless. 3481 02:16:06,520 --> 02:16:08,600 You can propel yourself to 3482 02:16:08,600 --> 02:16:11,640 the spacecraft ceiling with a 3483 02:16:11,640 --> 02:16:13,880 slight push off the floor. 3484 02:16:13,880 --> 02:16:15,120 You can go tumbling through 3485 02:16:15,120 --> 02:16:16,440 the air down the long axis 3486 02:16:16,440 --> 02:16:18,560 of the spacecraft. 3487 02:16:18,560 --> 02:16:21,400 Humans experience weightlessness 3488 02:16:21,400 --> 02:16:23,520 as joy. 3489 02:16:23,520 --> 02:16:24,640 This has been reported by 3490 02:16:24,640 --> 02:16:28,800 almost every astronaut and cosmonaut. 3491 02:16:28,800 --> 02:16:29,960 But because spacecraft are 3492 02:16:29,960 --> 02:16:32,160 still so small, and because 3493 02:16:32,160 --> 02:16:35,040 space walks have been done with 3494 02:16:35,040 --> 02:16:37,720 extreme caution, no human has 3495 02:16:37,720 --> 02:16:39,600 yet enjoyed this wonder and 3496 02:16:39,600 --> 02:16:43,241 glory, propelling yourself 3497 02:16:43,240 --> 02:16:44,679 by an almost imperceptible 3498 02:16:44,680 --> 02:16:47,600 push, with no machinery 3499 02:16:47,600 --> 02:16:50,480 driving you, untethered, 3500 02:16:50,479 --> 02:16:51,479 eventually with no 3501 02:16:51,479 --> 02:16:53,919 spacecraft in sight, high up 3502 02:16:53,920 --> 02:16:56,200 into the sky, into the 3503 02:16:56,200 --> 02:16:59,399 blackness of interplanetary space. 3504 02:16:59,399 --> 02:17:00,679 You become a living satellite 3505 02:17:00,680 --> 02:17:02,880 of the Earth, or a human 3506 02:17:02,880 --> 02:17:06,200 planet of the Sun. 3507 02:17:06,200 --> 02:17:08,479 Planetary exploration satisfies 3508 02:17:08,479 --> 02:17:09,879 our inclination for great 3509 02:17:09,880 --> 02:17:14,200 enterprises and wanderings and quests 3510 02:17:14,200 --> 02:17:15,399 that has been with us since 3511 02:17:15,399 --> 02:17:16,799 our days as hunters and 3512 02:17:16,800 --> 02:17:20,080 gatherers on the East African savannas 3513 02:17:20,080 --> 02:17:24,840 a million years ago. By chance. 3514 02:17:24,840 --> 02:17:25,960 It is possible, I say, to 3515 02:17:25,960 --> 02:17:27,760 imagine many skeins of historical 3516 02:17:27,760 --> 02:17:29,600 causality in which this would 3517 02:17:29,600 --> 02:17:31,600 not have transpired. 3518 02:17:31,600 --> 02:17:35,600 In our age, we're able to begin again. 3519 02:17:35,600 --> 02:17:36,080 Exploring 3520 02:17:36,080 --> 02:17:38,519 other worlds employs precisely 3521 02:17:38,520 --> 02:17:41,000 the same qualities of daring, 3522 02:17:41,000 --> 02:17:43,760 planning, cooperative enterprise, 3523 02:17:43,760 --> 02:17:45,760 and valor that mark the 3524 02:17:45,760 --> 02:17:49,360 finest in the military tradition. 3525 02:17:49,359 --> 02:17:51,240 Never mind the night launch of 3526 02:17:51,240 --> 02:17:53,120 Apollo spacecraft bound for 3527 02:17:53,120 --> 02:17:55,240 another world, that makes the 3528 02:17:55,240 --> 02:17:57,880 conclusion foregone. 3529 02:17:57,880 --> 02:18:01,040 Witness mere F-14s taking off 3530 02:18:01,040 --> 02:18:03,280 from adjacent flight decks, 3531 02:18:03,280 --> 02:18:05,359 gracefully canting left and 3532 02:18:05,359 --> 02:18:08,559 right after burners flaming, 3533 02:18:08,560 --> 02:18:09,360 and there's something that 3534 02:18:09,359 --> 02:18:12,080 sweeps you away, or at least 3535 02:18:12,080 --> 02:18:14,000 it does me. 3536 02:18:14,000 --> 02:18:15,160 And no amount of knowledge of 3537 02:18:15,160 --> 02:18:16,519 the potential abuses of 3538 02:18:16,520 --> 02:18:19,360 carrier task forces can affect the 3539 02:18:19,359 --> 02:18:21,160 depth of that feeling. 3540 02:18:21,160 --> 02:18:24,639 It simply speaks to another part of me. 3541 02:18:24,640 --> 02:18:26,720 It doesn't want recriminations 3542 02:18:26,720 --> 02:18:28,640 or politics. 3543 02:18:28,640 --> 02:18:33,241 It just wants to fly. 3544 02:18:33,240 --> 02:18:34,359 The philosopher Bertrand 3545 02:18:34,359 --> 02:18:40,960 Russell, in 1959, wrote as follows. 3546 02:18:40,960 --> 02:18:42,200 The future possibilities of 3547 02:18:42,200 --> 02:18:44,359 space travel, which are now 3548 02:18:44,359 --> 02:18:47,559 left mainly to unfounded fantasy, 3549 02:18:47,560 --> 02:18:50,040 could be more soberly treated, 3550 02:18:50,040 --> 02:18:51,000 without ceasing to be 3551 02:18:51,000 --> 02:18:53,439 interesting, and could show to even 3552 02:18:53,439 --> 02:18:54,759 the most adventurous of the 3553 02:18:54,760 --> 02:18:57,120 young that a world without 3554 02:18:57,120 --> 02:18:59,920 war need not be a world without 3555 02:18:59,920 --> 02:19:04,000 adventurous and hazardous glory. 3556 02:19:04,000 --> 02:19:05,640 To this kind of contest there 3557 02:19:05,640 --> 02:19:07,241 is no limit. 3558 02:19:07,240 --> 02:19:09,120 Each victory is only a 3559 02:19:09,120 --> 02:19:11,280 prelude to another, and no 3560 02:19:11,280 --> 02:19:14,920 boundaries can be set to rational hope. 3561 02:19:14,920 --> 02:19:17,080 Russell's phrase is noteworthy, 3562 02:19:17,080 --> 02:19:20,200 adventurous and hazardous glory. 3563 02:19:20,200 --> 02:19:21,960 Even if we could make human 3564 02:19:21,960 --> 02:19:24,080 spaceflight risk-free, and of 3565 02:19:24,080 --> 02:19:25,800 course we can't, it might 3566 02:19:25,800 --> 02:19:27,280 be counterproductive. 3567 02:19:27,280 --> 02:19:29,679 The hazard is an inseparable 3568 02:19:29,680 --> 02:19:32,440 component of the glory. 3569 02:19:32,439 --> 02:19:34,319 In the meantime, the most 3570 02:19:34,319 --> 02:19:35,799 important step we can take 3571 02:19:35,800 --> 02:19:38,120 toward Mars is to make significant 3572 02:19:38,120 --> 02:19:40,120 progress on Earth. 3573 02:19:40,120 --> 02:19:42,040 Even modest improvements in 3574 02:19:42,040 --> 02:19:43,120 the social, economic, and 3575 02:19:43,120 --> 02:19:44,280 political problems that our 3576 02:19:44,280 --> 02:19:47,120 global civilization now faces 3577 02:19:47,120 --> 02:19:49,000 could release enormous 3578 02:19:49,000 --> 02:19:51,240 resources, both material and 3579 02:19:51,240 --> 02:19:55,439 human, for other goals. 3580 02:19:55,439 --> 02:19:57,479 There's plenty of housework to 3581 02:19:57,479 --> 02:20:00,000 be done down here on Earth, 3582 02:20:00,000 --> 02:20:01,560 and our commitment to it must 3583 02:20:01,560 --> 02:20:04,040 be steadfast. 3584 02:20:04,040 --> 02:20:05,960 But we're the kind of species 3585 02:20:05,960 --> 02:20:08,800 that needs a frontier, 3586 02:20:08,800 --> 02:20:12,600 for fundamental biological reasons. 3587 02:20:12,600 --> 02:20:14,600 Every time humanity stretches 3588 02:20:14,600 --> 02:20:15,920 itself and 3589 02:20:15,920 --> 02:20:18,280 turns a new corner, it 3590 02:20:18,280 --> 02:20:20,040 receives a jolt of productive 3591 02:20:20,040 --> 02:20:22,040 vitality that can carry it 3592 02:20:22,040 --> 02:20:24,680 for centuries. 3593 02:20:24,680 --> 02:20:27,040 There's a new world next door 3594 02:20:27,040 --> 02:20:48,880 and we know how to get there. 3595 02:20:48,880 --> 02:20:50,840 The Voyager spacecraft are 3596 02:20:50,840 --> 02:20:52,960 bound for the stars. 3597 02:20:52,960 --> 02:20:54,560 They're on escape trajectories from 3598 02:20:54,560 --> 02:20:56,520 the solar system barreling 3599 02:20:56,520 --> 02:20:59,640 along at almost a million miles a day. 3600 02:20:59,640 --> 02:21:01,080 The gravitational fields of 3601 02:21:01,080 --> 02:21:02,359 Jupiter, Saturn, Uranus and 3602 02:21:02,359 --> 02:21:05,399 Neptune have flung them at such 3603 02:21:05,399 --> 02:21:07,200 high speeds that they've 3604 02:21:07,200 --> 02:21:09,359 broken the bonds that once 3605 02:21:09,359 --> 02:21:13,160 tied them to the Sun. 3606 02:21:13,160 --> 02:21:16,080 Have they left the solar system yet? 3607 02:21:16,080 --> 02:21:17,160 The answer depends very much 3608 02:21:17,160 --> 02:21:18,200 on how you define the 3609 02:21:18,200 --> 02:21:20,559 boundary of the Sun's realm. 3610 02:21:21,439 --> 02:21:22,479 If you define the outer 3611 02:21:22,479 --> 02:21:23,839 limits of the solar system as 3612 02:21:23,840 --> 02:21:26,200 the heliopause, where the 3613 02:21:26,200 --> 02:21:27,080 interplanetary 3614 02:21:27,080 --> 02:21:28,559 particles and magnetic fields 3615 02:21:28,560 --> 02:21:30,360 are replaced by their 3616 02:21:30,359 --> 02:21:34,240 interstellar counterparts, then neither 3617 02:21:34,240 --> 02:21:35,800 voyager has yet left the 3618 02:21:35,800 --> 02:21:37,760 solar system, although they 3619 02:21:37,760 --> 02:21:40,760 may do so in the next few decades. 3620 02:21:40,760 --> 02:21:42,000 But if your definition of the 3621 02:21:42,000 --> 02:21:44,080 edge of the solar system is 3622 02:21:44,080 --> 02:21:45,559 the distance at which our 3623 02:21:45,560 --> 02:21:47,920 stark and no longer hold 3624 02:21:47,920 --> 02:21:50,600 worlds in orbit around it, 3625 02:21:50,600 --> 02:21:51,880 then the Voyagers will not leave 3626 02:21:51,880 --> 02:21:53,720 the solar system for hundreds 3627 02:21:53,720 --> 02:21:55,040 of centuries. 3628 02:21:55,040 --> 02:21:57,399 Weakly grasped by the Sun's 3629 02:21:57,399 --> 02:21:59,200 gravity in every 3630 02:21:59,200 --> 02:22:02,200 direction in the sky is that 3631 02:22:02,200 --> 02:22:04,880 immense horde of a trillion 3632 02:22:04,880 --> 02:22:09,680 comets or more, the Oort Cloud. 3633 02:22:09,680 --> 02:22:11,000 The two Voyager spacecraft 3634 02:22:11,000 --> 02:22:12,040 will finish their passage 3635 02:22:12,040 --> 02:22:14,720 through the Oort Cloud in another 3636 02:22:14,720 --> 02:22:18,040 20,000 years or so. 3637 02:22:18,040 --> 02:22:20,640 Then at last, completing their 3638 02:22:20,640 --> 02:22:21,760 long goodbye to the 3639 02:22:21,760 --> 02:22:25,120 solar system, broken free of 3640 02:22:25,120 --> 02:22:27,760 the gravitational shackles that 3641 02:22:27,760 --> 02:22:28,360 once bound 3642 02:22:28,359 --> 02:22:31,639 them to the Sun, the Voyagers 3643 02:22:31,640 --> 02:22:33,840 will make for the open sea 3644 02:22:33,840 --> 02:22:36,680 of interstellar space. 3645 02:22:36,680 --> 02:22:39,840 Only then will phase two of 3646 02:22:39,840 --> 02:22:42,760 their mission begin. 3647 02:22:42,760 --> 02:22:43,920 Their radio transmitters 3648 02:22:43,920 --> 02:22:46,440 long dead, the spacecraft will 3649 02:22:46,439 --> 02:22:49,599 wander for ages in the calm, 3650 02:22:49,600 --> 02:22:53,201 cold, interstellar blackness, 3651 02:22:53,200 --> 02:22:54,559 where there is almost nothing 3652 02:22:54,560 --> 02:22:56,560 to erode them. 3653 02:22:56,560 --> 02:22:58,720 Once out of the solar system, 3654 02:22:58,720 --> 02:22:59,560 they will remain 3655 02:22:59,560 --> 02:23:01,960 intact for a billion years or 3656 02:23:01,960 --> 02:23:04,040 more, as they circumnavigate 3657 02:23:04,040 --> 02:23:07,880 the center of the Milky Way galaxy. 3658 02:23:07,880 --> 02:23:09,240 We do not know whether there 3659 02:23:09,240 --> 02:23:11,559 are other spacefaring 3660 02:23:11,560 --> 02:23:14,480 civilizations in the Milky Way. 3661 02:23:14,479 --> 02:23:16,479 If they do exist, we don't 3662 02:23:16,479 --> 02:23:17,759 know how abundant they 3663 02:23:17,760 --> 02:23:20,440 are, much less where they are. 3664 02:23:21,279 --> 02:23:23,000 But there is at least a 3665 02:23:23,000 --> 02:23:24,760 chance that sometime in 3666 02:23:24,760 --> 02:23:26,560 the remote future, one of the 3667 02:23:26,560 --> 02:23:29,201 Voyagers will be intercepted 3668 02:23:29,200 --> 02:23:33,000 and examined by an alien craft. 3669 02:23:33,000 --> 02:23:35,080 Accordingly, as each Voyager 3670 02:23:35,080 --> 02:23:36,479 left Earth for the planets and the 3671 02:23:36,479 --> 02:23:39,160 stars, it carried with it a 3672 02:23:39,160 --> 02:23:41,080 golden phonograph record, 3673 02:23:41,080 --> 02:23:46,559 encased in a golden mirrored jacket, 3674 02:23:46,560 --> 02:23:50,040 containing, among other things, 3675 02:23:50,040 --> 02:23:51,680 greetings in 59 human 3676 02:23:51,680 --> 02:23:58,560 languages, and one whale language, 3677 02:23:58,560 --> 02:24:00,920 a 12-minute sound essay, 3678 02:24:00,920 --> 02:24:02,720 including a kiss, a baby's 3679 02:24:02,720 --> 02:24:05,400 cry, and an EEG record of 3680 02:24:05,399 --> 02:24:06,519 the meditations 3681 02:24:06,520 --> 02:24:09,280 of a young woman in love. 3682 02:24:09,279 --> 02:24:12,960 116 encoded pictures on our 3683 02:24:12,960 --> 02:24:15,359 science, our civilization, 3684 02:24:15,359 --> 02:24:17,479 and ourselves. 3685 02:24:17,479 --> 02:24:18,879 And 90 minutes of the Earth's 3686 02:24:18,880 --> 02:24:20,359 greatest hits. 3687 02:24:21,000 --> 02:24:21,600 Eastern and 3688 02:24:21,600 --> 02:24:25,000 Western, classical and folk, 3689 02:24:25,000 --> 02:24:26,680 including a Navajo night 3690 02:24:26,680 --> 02:24:29,280 chant, a Japanese shakuhachi 3691 02:24:29,279 --> 02:24:31,240 piece, a pygmy girl's 3692 02:24:31,240 --> 02:24:33,719 initiation song, a Peruvian 3693 02:24:33,720 --> 02:24:36,280 wedding song, a 3,000 year old 3694 02:24:36,279 --> 02:24:38,519 composition for the chin 3695 02:24:38,520 --> 02:24:41,840 called Flowing Streams, Bach, 3696 02:24:41,840 --> 02:24:43,319 Beethoven, Mozart, 3697 02:24:43,319 --> 02:24:46,319 Stravinsky, Louis Armstrong, 3698 02:24:46,319 --> 02:24:48,319 Blind Willie Johnson, and 3699 02:24:48,319 --> 02:24:50,160 Chuck Berry's Johnny B. 3700 02:24:50,160 --> 02:24:54,359 Goode. Space is nearly empty. 3701 02:24:54,359 --> 02:24:55,519 There's virtually no chance 3702 02:24:55,520 --> 02:24:56,640 that one of the Voyagers will 3703 02:24:56,640 --> 02:24:59,161 ever enter another solar system. 3704 02:24:59,160 --> 02:25:01,160 And this is true even if 3705 02:25:01,160 --> 02:25:02,760 every star in the sky is 3706 02:25:02,760 --> 02:25:05,200 accompanied by planets. 3707 02:25:05,200 --> 02:25:06,519 The instructions on the record 3708 02:25:06,520 --> 02:25:10,121 jackets, written in what we believe 3709 02:25:10,120 --> 02:25:12,479 to be readily comprehensible 3710 02:25:12,479 --> 02:25:15,319 scientific hieroglyphics, can 3711 02:25:15,319 --> 02:25:17,519 be read and the contents of 3712 02:25:17,520 --> 02:25:20,520 the records understood. 3713 02:25:20,520 --> 02:25:22,800 Only if alien beings somewhere 3714 02:25:22,800 --> 02:25:24,760 in the remote future find 3715 02:25:24,760 --> 02:25:26,640 Voyager in the depths 3716 02:25:26,640 --> 02:25:29,161 of interstellar space. 3717 02:25:29,160 --> 02:25:30,319 Since both Voyagers will 3718 02:25:30,319 --> 02:25:31,120 circle the center of the 3719 02:25:31,120 --> 02:25:34,080 Milky Way galaxy essentially forever. 3720 02:25:34,080 --> 02:25:35,120 There's plenty of time for 3721 02:25:35,120 --> 02:25:37,359 the records to be found, if 3722 02:25:37,359 --> 02:25:37,880 there's anyone 3723 02:25:37,880 --> 02:25:40,319 out there to do the finding. 3724 02:25:40,319 --> 02:25:41,160 We can't know how much of 3725 02:25:41,160 --> 02:25:43,680 the records they would understand. 3726 02:25:43,680 --> 02:25:45,600 Surely the greetings would be 3727 02:25:45,600 --> 02:25:47,560 incomprehensible, but their 3728 02:25:47,560 --> 02:25:50,320 intent may not be. We thought it 3729 02:25:50,319 --> 02:25:53,920 would be impolite not to say hello. 3730 02:25:53,920 --> 02:25:55,160 The hypothetical aliens are 3731 02:25:55,160 --> 02:25:56,680 bound to be very different from 3732 02:25:56,680 --> 02:25:59,320 us, since they're independently 3733 02:25:59,319 --> 02:26:02,000 evolved in another world, are 3734 02:26:02,000 --> 02:26:03,040 we really sure they 3735 02:26:03,040 --> 02:26:04,720 can understand anything at all 3736 02:26:04,720 --> 02:26:08,600 of our message? Every time I feel these 3737 02:26:08,600 --> 02:26:09,360 concerns 3738 02:26:09,359 --> 02:26:13,799 stirring though, I reassure myself. 3739 02:26:13,800 --> 02:26:14,560 Whatever the 3740 02:26:14,560 --> 02:26:16,560 incomprehensibilities of the 3741 02:26:16,560 --> 02:26:19,241 Voyager record, any alien ship 3742 02:26:19,240 --> 02:26:21,160 that finds it will have 3743 02:26:21,160 --> 02:26:22,519 another standard by 3744 02:26:22,520 --> 02:26:24,680 which to judge us, because 3745 02:26:24,680 --> 02:26:28,400 each Voyager is itself a message. 3746 02:26:28,399 --> 02:26:31,479 In their exploratory intent, 3747 02:26:31,479 --> 02:26:33,040 in the lofty ambition of 3748 02:26:33,040 --> 02:26:35,840 their objectives, in their 3749 02:26:35,840 --> 02:26:39,240 utter lack of intent to do harm, 3750 02:26:39,240 --> 02:26:40,479 and in the brilliance of 3751 02:26:40,479 --> 02:26:43,040 their design and performance, 3752 02:26:43,040 --> 02:26:48,319 these robots speak eloquently for us. 3753 02:26:48,319 --> 02:26:49,679 But being much more advanced 3754 02:26:49,680 --> 02:26:52,120 scientists and engineers than we, 3755 02:26:52,120 --> 02:26:53,559 otherwise they'd never be able 3756 02:26:53,560 --> 02:26:56,760 to find and retrieve the small, silent 3757 02:26:56,760 --> 02:27:00,680 spacecraft in interstellar space. 3758 02:27:00,680 --> 02:27:02,160 Perhaps the aliens would have no 3759 02:27:02,160 --> 02:27:03,680 difficulty understanding what 3760 02:27:03,680 --> 02:27:07,241 is encoded on these golden records. 3761 02:27:07,240 --> 02:27:08,319 Perhaps they 3762 02:27:08,319 --> 02:27:10,319 would recognize the 3763 02:27:10,319 --> 02:27:13,599 tentativeness of our society, 3764 02:27:13,600 --> 02:27:15,600 the mismatch between our 3765 02:27:15,600 --> 02:27:18,600 technology and our wisdom. 3766 02:27:18,600 --> 02:27:20,280 Had we destroyed ourselves 3767 02:27:20,279 --> 02:27:22,120 since launching Voyager, they 3768 02:27:22,120 --> 02:27:24,479 might wonder, or have we gone 3769 02:27:24,479 --> 02:27:28,000 on to greater things? 3770 02:27:28,000 --> 02:27:29,120 Or perhaps the records will 3771 02:27:29,120 --> 02:27:30,680 never be intercepted. 3772 02:27:30,680 --> 02:27:31,960 Perhaps no one in five 3773 02:27:31,960 --> 02:27:35,240 billion years will ever come upon them. 3774 02:27:35,240 --> 02:27:38,240 Five billion years is a long time. 3775 02:27:38,240 --> 02:27:40,000 In five billion years, all 3776 02:27:40,000 --> 02:27:41,040 humans will have become 3777 02:27:41,040 --> 02:27:45,080 extinct or evolved into other beings. 3778 02:27:45,080 --> 02:27:46,600 None of our artifacts will 3779 02:27:46,600 --> 02:27:49,480 have survived on Earth. 3780 02:27:49,479 --> 02:27:51,319 The continents will have 3781 02:27:51,319 --> 02:27:53,599 become unrecognizably altered 3782 02:27:53,600 --> 02:27:56,121 or destroyed, 3783 02:27:56,120 --> 02:27:58,200 and the evolution of the Sun 3784 02:27:58,200 --> 02:28:01,679 will have burned the Earth to a crisp, 3785 02:28:01,680 --> 02:28:08,680 or reduced it to a world of adults. 3786 02:28:08,680 --> 02:28:11,880 and far from home, untouched 3787 02:28:11,880 --> 02:28:14,160 by these remote events, the 3788 02:28:14,160 --> 02:28:16,399 voyagers, bearing the 3789 02:28:16,399 --> 02:28:17,879 memories of a world that is 3790 02:28:17,880 --> 02:28:20,120 no more, will fly on. 3791 02:28:46,920 --> 02:28:50,120 The Sun is the nearest star, a 3792 02:28:50,120 --> 02:28:52,720 glowing sphere of gas, shining 3793 02:28:52,720 --> 02:28:54,440 because of its heat, like a 3794 02:28:54,439 --> 02:28:56,359 red-hot poker. 3795 02:28:56,359 --> 02:28:58,120 The surface we see in ordinary 3796 02:28:58,120 --> 02:28:59,920 visible light is at 6,000 3797 02:28:59,920 --> 02:29:02,560 degrees centigrade, but in its 3798 02:29:02,560 --> 02:29:04,280 hidden interior, in the 3799 02:29:04,279 --> 02:29:05,920 nuclear furnace where sunlight 3800 02:29:05,920 --> 02:29:08,040 is ultimately generated, its 3801 02:29:08,040 --> 02:29:08,920 temperature 3802 02:29:08,920 --> 02:29:11,640 is 20 million degrees. 3803 02:29:11,640 --> 02:29:14,120 All this churning power is 3804 02:29:14,120 --> 02:29:16,800 driven by the Sun's interior, which is 3805 02:29:16,800 --> 02:29:19,080 converting 400 million tons of 3806 02:29:19,080 --> 02:29:22,399 hydrogen into helium every second. 3807 02:29:22,399 --> 02:29:25,080 The Sun is a great fusion 3808 02:29:25,080 --> 02:29:27,040 reactor into which a million 3809 02:29:27,040 --> 02:29:28,960 Earths would fit. 3810 02:29:28,960 --> 02:29:31,200 Luckily for us it's safely 3811 02:29:31,200 --> 02:29:36,720 placed 150 million kilometers away. 3812 02:29:36,720 --> 02:29:38,360 It is the destiny of stars 3813 02:29:38,359 --> 02:29:41,599 to collapse but on 3814 02:29:41,600 --> 02:29:43,201 their ways to their separate 3815 02:29:43,200 --> 02:29:47,040 fates all stars experience a 3816 02:29:47,040 --> 02:29:49,080 premonition of death. 3817 02:29:49,080 --> 02:29:50,640 Before the final gravitational 3818 02:29:50,640 --> 02:29:54,000 collapse, the star shudders, 3819 02:29:54,000 --> 02:29:57,880 briefly swells into some grotesque 3820 02:29:57,880 --> 02:29:59,680 parody of itself. 3821 02:29:59,680 --> 02:30:01,520 With its last gasp, it 3822 02:30:01,520 --> 02:30:04,480 becomes a red giant. 3823 02:30:04,479 --> 02:30:06,200 Some five billion years from 3824 02:30:06,200 --> 02:30:08,639 now, there will be a last 3825 02:30:08,640 --> 02:30:11,640 perfect day on Earth. 3826 02:30:11,640 --> 02:30:14,080 Then, the Sun will slowly 3827 02:30:14,080 --> 02:30:18,880 change, and the Earth will die. 3828 02:30:18,880 --> 02:30:20,000 There is only so much 3829 02:30:20,000 --> 02:30:21,960 hydrogen fuel in the Sun, 3830 02:30:21,960 --> 02:30:23,520 when it's almost all converted 3831 02:30:23,520 --> 02:30:24,560 to helium, 3832 02:30:24,560 --> 02:30:25,960 the solar interior will 3833 02:30:25,960 --> 02:30:28,439 continue its original collapse, 3834 02:30:28,439 --> 02:30:30,799 the higher temperatures in its core 3835 02:30:30,800 --> 02:30:31,800 will make the outside of the 3836 02:30:31,800 --> 02:30:34,440 Sun expand, and the Earth 3837 02:30:34,439 --> 02:30:36,960 will become slowly warmer. 3838 02:30:36,960 --> 02:30:39,000 Eventually, life will be 3839 02:30:39,000 --> 02:30:41,439 extinguished, the oceans will 3840 02:30:41,439 --> 02:30:45,160 evaporate and boil, and our atmosphere 3841 02:30:45,160 --> 02:30:48,080 will gush away to space. 3842 02:30:48,080 --> 02:30:50,279 The Sun will become a bloated 3843 02:30:50,279 --> 02:30:52,920 red giant star, filling the 3844 02:30:52,920 --> 02:30:55,800 sky, enveloping and devouring 3845 02:30:55,800 --> 02:30:58,160 the planets Mercury and Venus, 3846 02:30:58,160 --> 02:31:01,399 and probably the Earth as well. 3847 02:31:01,399 --> 02:31:03,559 The inner solar system will 3848 02:31:03,560 --> 02:31:08,241 reside inside the Sun, but 3849 02:31:08,240 --> 02:31:10,920 perhaps by then our descendants 3850 02:31:10,920 --> 02:31:14,080 will have ventured somewhere else. 3851 02:31:14,080 --> 02:31:16,279 In its final agonies, the Sun 3852 02:31:16,279 --> 02:31:18,639 will slowly pulsate. 3853 02:31:18,640 --> 02:31:20,480 By then, its core will have 3854 02:31:20,479 --> 02:31:21,959 become so hot that it 3855 02:31:21,960 --> 02:31:23,880 temporarily converts helium 3856 02:31:23,880 --> 02:31:25,359 into carbon. 3857 02:31:25,359 --> 02:31:27,040 The ash from today's nuclear 3858 02:31:27,040 --> 02:31:29,519 fusion will become the fuel 3859 02:31:29,520 --> 02:31:31,161 to power the Sun near the end of 3860 02:31:31,160 --> 02:31:34,479 its life, in its red giant stage. 3861 02:31:34,479 --> 02:31:36,639 Then the Sun will lose great 3862 02:31:36,640 --> 02:31:38,800 shells of its outer atmosphere 3863 02:31:38,800 --> 02:31:41,000 to space, filling the solar 3864 02:31:41,000 --> 02:31:42,840 system with eerily glowing 3865 02:31:42,840 --> 02:31:47,040 gas, the ghost of a star outward bound. 3866 02:31:47,040 --> 02:31:48,279 Perhaps half the mass of the 3867 02:31:48,279 --> 02:31:49,840 Sun will be lost in this way. 3868 02:31:50,640 --> 02:31:52,760 Viewed from elsewhere, our system 3869 02:31:52,760 --> 02:31:54,720 will then resemble the Ring 3870 02:31:54,720 --> 02:31:57,241 Nebula in Lyra, the atmosphere 3871 02:31:57,240 --> 02:31:59,359 of the Sun expanding outward 3872 02:31:59,359 --> 02:32:01,080 like a soap bubble. 3873 02:32:01,080 --> 02:32:02,680 And at the very center will 3874 02:32:02,680 --> 02:32:05,080 be a white dwarf, the hot 3875 02:32:05,080 --> 02:32:07,479 exposed core of the Sun, its 3876 02:32:07,479 --> 02:32:09,719 nuclear fuel now exhausted, 3877 02:32:09,720 --> 02:32:11,640 slowly cooling to become a 3878 02:32:11,640 --> 02:32:16,040 cold, dead star. Such is the life of an 3879 02:32:16,040 --> 02:32:19,359 ordinary star, born in a gas cloud, 3880 02:32:19,359 --> 02:32:21,279 maturing as a yellow sun, 3881 02:32:21,279 --> 02:32:23,479 decaying as a red giant, and 3882 02:32:23,479 --> 02:32:25,040 dying as a white dwarf 3883 02:32:25,040 --> 02:32:31,160 enveloped in its shroud of gas. 3884 02:32:31,160 --> 02:32:33,240 The cosmos was originally all 3885 02:32:33,240 --> 02:32:35,200 hydrogen and helium. 3886 02:32:35,200 --> 02:32:36,479 Heavier elements were made in 3887 02:32:36,479 --> 02:32:38,799 red giants and supernovas 3888 02:32:38,800 --> 02:32:41,040 and then blown off to space, 3889 02:32:41,040 --> 02:32:42,319 where they were available for 3890 02:32:42,319 --> 02:32:44,000 subsequent generations 3891 02:32:44,000 --> 02:32:45,800 of stars and planets. 3892 02:32:45,800 --> 02:32:48,120 Our Sun is probably a third 3893 02:32:48,120 --> 02:32:49,840 generation star. 3894 02:32:49,840 --> 02:32:51,680 Except for hydrogen and helium, 3895 02:32:51,680 --> 02:32:53,880 every atom in the Sun and the Earth 3896 02:32:53,880 --> 02:32:56,800 was synthesized in other stars. 3897 02:32:56,800 --> 02:32:58,400 The silicon in the rocks, the 3898 02:32:58,399 --> 02:33:00,559 oxygen in the air, the carbon 3899 02:33:00,560 --> 02:33:02,241 in our DNA, the gold in our 3900 02:33:02,240 --> 02:33:04,359 banks, the uranium in our 3901 02:33:04,359 --> 02:33:06,960 arsenals, were all made 3902 02:33:06,960 --> 02:33:09,040 thousands of light years away 3903 02:33:09,040 --> 02:33:09,880 and billions 3904 02:33:09,880 --> 02:33:11,400 of years ago. 3905 02:33:11,399 --> 02:33:14,519 Our planet, our society, and 3906 02:33:14,520 --> 02:33:19,760 we ourselves are built of star stuff. 3907 02:33:21,920 --> 02:33:23,640 The lives and deaths of the 3908 02:33:23,640 --> 02:33:26,600 stars seem impossibly remote 3909 02:33:26,600 --> 02:33:28,720 from human experience, and yet we're 3910 02:33:28,720 --> 02:33:30,080 related in the most intimate 3911 02:33:30,080 --> 02:33:32,240 way to their life cycles. 3912 02:33:32,240 --> 02:33:33,599 The very matter that makes us 3913 02:33:33,600 --> 02:33:35,440 up was generated 3914 02:33:35,439 --> 02:33:38,080 long ago and far away in red 3915 02:33:38,080 --> 02:33:40,479 giant stars. 3916 02:33:40,479 --> 02:33:44,120 A blade of grass, as Walt Whitman said, 3917 02:33:44,120 --> 02:33:46,800 is the journey work of the stars. 3918 02:33:46,800 --> 02:33:48,080 The formation of the solar 3919 02:33:48,080 --> 02:33:49,279 system may have been triggered 3920 02:33:49,279 --> 02:33:51,960 by a nearby supernova explosion. 3921 02:33:51,960 --> 02:33:53,600 After the Sun turned on its 3922 02:33:53,600 --> 02:33:55,000 ultraviolet light 3923 02:33:55,000 --> 02:33:56,560 poured into our atmosphere, 3924 02:33:56,560 --> 02:33:58,840 its warmth generated lightning, 3925 02:33:58,840 --> 02:33:59,920 and these energy sources 3926 02:33:59,920 --> 02:34:02,800 sparked the origin of life. 3927 02:34:02,800 --> 02:34:05,240 Plants harvest sunlight, 3928 02:34:05,240 --> 02:34:09,000 converting solar into chemical energy. 3929 02:34:09,000 --> 02:34:10,359 We and the other animals are 3930 02:34:10,359 --> 02:34:12,639 parasites on the plants, so 3931 02:34:12,640 --> 02:34:16,640 we are, all of us, solar-powered. 3932 02:34:16,640 --> 02:34:17,720 The evolution of life is 3933 02:34:17,720 --> 02:34:19,760 driven by mutations, their 3934 02:34:19,760 --> 02:34:21,920 cause partly by natural radioactivity 3935 02:34:21,920 --> 02:34:24,279 and cosmic rays, but they are 3936 02:34:24,279 --> 02:34:25,399 both generated in the 3937 02:34:25,399 --> 02:34:27,879 spectacular deaths of massive stars 3938 02:34:27,880 --> 02:34:31,760 thousands of light-years distant. 3939 02:34:31,760 --> 02:34:33,840 Think of the Sun's heat on 3940 02:34:33,840 --> 02:34:35,680 your upturned face on a 3941 02:34:35,680 --> 02:34:37,920 cloudless summer's day. 3942 02:34:37,920 --> 02:34:40,440 From 150 million kilometers 3943 02:34:40,439 --> 02:34:44,080 away, we recognize its power. 3944 02:34:44,080 --> 02:34:44,600 What would we 3945 02:34:44,600 --> 02:34:46,121 feel on its seething 3946 02:34:46,120 --> 02:34:48,240 self-luminous surface or 3947 02:34:48,240 --> 02:34:51,059 immerse in its heart of nuclear fire? 3948 02:34:51,060 --> 02:34:53,161 And And yet, the Sun is an 3949 02:34:53,160 --> 02:34:56,880 ordinary, even a mediocre star. 3950 02:34:56,880 --> 02:34:58,520 Our ancestors worshipped the 3951 02:34:58,520 --> 02:35:00,960 Sun and they were far from foolish. 3952 02:35:00,960 --> 02:35:02,359 It makes good sense to revere 3953 02:35:02,359 --> 02:35:04,200 the Sun and the stars, 3954 02:35:04,200 --> 02:35:10,960 because we are their children. 3955 02:35:10,960 --> 02:35:12,600 We have witnessed the life 3956 02:35:12,600 --> 02:35:15,320 cycles of the stars. 3957 02:35:15,319 --> 02:35:18,160 They are born, they mature, 3958 02:35:18,160 --> 02:35:20,040 and then they die. 3959 02:35:20,040 --> 02:35:21,240 As time goes on, there are 3960 02:35:21,240 --> 02:35:22,519 more white dwarfs, more 3961 02:35:22,520 --> 02:35:25,121 neutron stars, more black holes. 3962 02:35:25,120 --> 02:35:26,720 The remains of the stars 3963 02:35:26,720 --> 02:35:30,360 accumulate as the eons pass. 3964 02:35:30,359 --> 02:35:31,679 But interstellar space also 3965 02:35:31,680 --> 02:35:33,120 becomes progressively enriched 3966 02:35:33,120 --> 02:35:34,439 in heavy elements, 3967 02:35:34,439 --> 02:35:35,879 out of which form new 3968 02:35:35,880 --> 02:35:37,600 generations of stars and 3969 02:35:37,600 --> 02:35:40,880 planets, life and intelligence. 3970 02:35:40,880 --> 02:35:42,440 The events in one star can 3971 02:35:42,439 --> 02:35:43,759 influence a world halfway 3972 02:35:43,760 --> 02:35:45,520 across the galaxy and a 3973 02:35:45,520 --> 02:35:49,081 billion years in the future. 3974 02:35:49,080 --> 02:35:50,960 Surrounding the Milky Way is 3975 02:35:50,960 --> 02:35:53,000 a halo of matter, which 3976 02:35:53,000 --> 02:35:56,240 includes the globular clusters, each 3977 02:35:56,240 --> 02:35:57,880 containing up to a million 3978 02:35:57,880 --> 02:35:59,680 elderly stars. 3979 02:35:59,680 --> 02:36:01,040 At the centers of globular 3980 02:36:01,040 --> 02:36:02,920 clusters and at the core of 3981 02:36:02,920 --> 02:36:05,240 the galaxy, there may be massive 3982 02:36:05,240 --> 02:36:07,559 black holes ticking and 3983 02:36:07,560 --> 02:36:09,720 purring, the subject of 3984 02:36:09,720 --> 02:36:11,440 future exploration. 3985 02:36:11,439 --> 02:36:13,160 We on Earth marvel, and 3986 02:36:13,160 --> 02:36:15,319 rightly so, at the daily 3987 02:36:15,319 --> 02:36:17,719 return of our single sun. 3988 02:36:17,720 --> 02:36:19,200 But from a planet orbiting a 3989 02:36:19,200 --> 02:36:20,760 star in a distant globular 3990 02:36:20,760 --> 02:36:23,240 cluster, a still more glorious 3991 02:36:23,240 --> 02:36:24,679 dawn awaits. 3992 02:36:24,680 --> 02:36:28,241 Not a sunrise, but a galaxy rise. 3993 02:36:28,240 --> 02:36:30,439 A morning filled with 400 3994 02:36:30,439 --> 02:36:32,919 billion suns, the rising of 3995 02:36:32,920 --> 02:36:34,600 the Milky Way. 3996 02:36:34,600 --> 02:36:37,161 An enormous spiral form with 3997 02:36:37,160 --> 02:36:38,760 collapsing gas clouds, 3998 02:36:38,760 --> 02:36:41,440 condensing planetary systems, luminous 3999 02:36:41,439 --> 02:36:43,839 supergiants, stable middle-aged 4000 02:36:43,840 --> 02:36:45,920 stars, red giants, white 4001 02:36:45,920 --> 02:36:49,560 dwarfs, planetary nebulas, supernovas, 4002 02:36:49,560 --> 02:36:52,040 neutron stars, pulsars, black 4003 02:36:52,040 --> 02:36:54,479 holes, and, there is every 4004 02:36:54,479 --> 02:36:56,559 reason to think, other exotic 4005 02:36:56,560 --> 02:36:58,000 objects that we have not 4006 02:36:58,000 --> 02:37:02,120 yet discovered. 4007 02:37:02,120 --> 02:37:04,160 From such a world high above 4008 02:37:04,160 --> 02:37:06,240 the disk of the Milky Way, 4009 02:37:06,240 --> 02:37:08,359 it would be clear, as it is beginning 4010 02:37:08,359 --> 02:37:10,399 to be clear on our world, 4011 02:37:10,399 --> 02:37:11,719 that we are made by the 4012 02:37:11,720 --> 02:37:14,960 atoms and the stars, that our matter 4013 02:37:14,960 --> 02:37:17,920 and our form are determined 4014 02:37:17,920 --> 02:37:41,279 by the cosmos of which we are a part. 4015 02:37:41,279 --> 02:37:42,800 Here we are in the 4016 02:37:42,800 --> 02:37:45,560 constellation Andromeda. 4017 02:37:45,560 --> 02:37:49,280 This star is Beta Andromedae. 4018 02:37:49,279 --> 02:37:51,559 The light by which we see 4019 02:37:51,560 --> 02:37:54,680 this star has spent 75 years 4020 02:37:54,680 --> 02:37:56,480 traversing interstellar space on 4021 02:37:56,479 --> 02:37:59,160 its journey to the Earth. 4022 02:37:59,160 --> 02:38:01,080 In the unlikely event that 4023 02:38:01,080 --> 02:38:03,920 Beta Andromedae blew itself up 4024 02:38:03,920 --> 02:38:06,040 a week ago Tuesday, we will 4025 02:38:06,040 --> 02:38:07,319 not know of it for another 4026 02:38:07,319 --> 02:38:10,279 75 years as this interesting 4027 02:38:10,279 --> 02:38:12,080 information traveling at the speed 4028 02:38:12,080 --> 02:38:14,080 of light crosses the enormous 4029 02:38:14,080 --> 02:38:16,720 interstellar distances. 4030 02:38:16,720 --> 02:38:17,720 When the light we see from 4031 02:38:17,720 --> 02:38:20,640 the star set out on its long 4032 02:38:20,640 --> 02:38:22,960 interstellar voyage, the young 4033 02:38:22,960 --> 02:38:26,520 Albert Einstein, working as a 4034 02:38:26,520 --> 02:38:28,760 Swiss patent clerk, had just 4035 02:38:28,760 --> 02:38:30,720 published his epical special 4036 02:38:30,720 --> 02:38:34,560 theory of relativity here on Earth. 4037 02:38:34,560 --> 02:38:37,880 We see that space and time 4038 02:38:37,880 --> 02:38:40,359 are intertwined. 4039 02:38:40,359 --> 02:38:43,479 we cannot look out into space 4040 02:38:43,479 --> 02:38:46,919 without looking back into time. 4041 02:38:46,920 --> 02:38:47,480 The speed of 4042 02:38:47,479 --> 02:38:52,040 light is very fast but space 4043 02:38:52,040 --> 02:38:55,040 is very empty and the stars 4044 02:38:55,040 --> 02:38:57,120 are very far apart. 4045 02:38:57,120 --> 02:38:58,359 In fact the distances that 4046 02:38:58,359 --> 02:38:59,479 we've been talking about up 4047 02:38:59,479 --> 02:39:01,359 to now are very small 4048 02:39:01,359 --> 02:39:04,599 by the usual astronomical standards. 4049 02:39:04,600 --> 02:39:06,560 In fact the distance from the 4050 02:39:06,560 --> 02:39:07,360 Earth to the 4051 02:39:07,359 --> 02:39:08,559 center of the Milky Way 4052 02:39:08,560 --> 02:39:13,400 galaxy is 30,000 light-years. 4053 02:39:13,399 --> 02:39:15,240 From our galaxy to the 4054 02:39:15,240 --> 02:39:17,240 nearest spiral galaxy like our 4055 02:39:17,240 --> 02:39:22,519 own, called M31, is two 4056 02:39:22,520 --> 02:39:25,720 million light-years. 4057 02:39:25,720 --> 02:39:27,560 When the light we see today 4058 02:39:27,560 --> 02:39:30,560 from M31 left on its journey 4059 02:39:30,560 --> 02:39:32,121 for Earth, there were 4060 02:39:32,120 --> 02:39:34,000 no human beings on the Earth, 4061 02:39:34,000 --> 02:39:36,279 although our ancestors were 4062 02:39:36,279 --> 02:39:37,679 nicely evolving and 4063 02:39:37,680 --> 02:39:41,160 very rapidly to our present form. 4064 02:39:41,160 --> 02:39:42,040 There are much greater 4065 02:39:42,040 --> 02:39:44,399 distances in astronomy. The distance 4066 02:39:44,399 --> 02:39:45,920 from the Earth to the most 4067 02:39:45,920 --> 02:39:49,600 distant quasars is 8 or 10 4068 02:39:49,600 --> 02:39:52,560 billion light years. We see them 4069 02:39:52,560 --> 02:39:54,800 as they were before the Earth 4070 02:39:54,800 --> 02:39:57,200 itself accumulated, before the 4071 02:39:57,200 --> 02:40:00,359 Milky Way galaxy was formed. The 4072 02:40:00,359 --> 02:40:01,920 fastest space vehicles ever 4073 02:40:01,920 --> 02:40:03,760 launched by the human species 4074 02:40:03,760 --> 02:40:06,000 are the Voyager spacecraft. 4075 02:40:06,000 --> 02:40:07,880 They are traveling so fast 4076 02:40:07,880 --> 02:40:10,600 that it's only 10,000 times 4077 02:40:10,600 --> 02:40:13,480 slower than the speed of light. 4078 02:40:13,479 --> 02:40:14,639 The Voyager spacecraft will 4079 02:40:14,640 --> 02:40:16,720 take 40,000 years to go the 4080 02:40:16,720 --> 02:40:18,760 distance to the nearest stars, and 4081 02:40:18,760 --> 02:40:19,880 they're not even headed 4082 02:40:19,880 --> 02:40:22,080 towards the nearest stars. 4083 02:40:22,080 --> 02:40:23,559 But is there a method by 4084 02:40:23,560 --> 02:40:25,040 which we could travel in a 4085 02:40:25,040 --> 02:40:28,479 conveniently short time to the stars? 4086 02:40:28,479 --> 02:40:29,839 Can we travel close to the 4087 02:40:29,840 --> 02:40:31,520 speed of light? 4088 02:40:31,520 --> 02:40:32,760 And what's magic about the 4089 02:40:32,760 --> 02:40:34,480 speed of light? 4090 02:40:34,479 --> 02:40:37,240 Can't we travel faster than that? 4091 02:40:37,240 --> 02:40:39,040 It turns out that there is 4092 02:40:39,040 --> 02:40:41,560 something very strange about 4093 02:40:41,560 --> 02:40:43,000 the speed of light. 4094 02:40:43,000 --> 02:40:44,479 Something that provides the 4095 02:40:44,479 --> 02:40:46,639 key to our understanding of 4096 02:40:46,640 --> 02:40:49,320 time and space. 4097 02:40:49,319 --> 02:40:50,559 If the world is to be 4098 02:40:50,560 --> 02:40:52,560 understood, if we are to 4099 02:40:52,560 --> 02:40:55,680 avoid logical paradoxes when travelling 4100 02:40:55,680 --> 02:40:57,040 at high speeds, then there 4101 02:40:57,040 --> 02:40:59,600 are certain rules which must be obeyed. 4102 02:40:59,600 --> 02:41:01,640 Einstein called these rules 4103 02:41:01,640 --> 02:41:04,560 the special theory of relativity. 4104 02:41:04,560 --> 02:41:05,840 Light from a moving object 4105 02:41:05,840 --> 02:41:07,279 travels at the same speed 4106 02:41:07,279 --> 02:41:08,359 no matter whether the object 4107 02:41:08,359 --> 02:41:11,200 is at rest or in motion. 4108 02:41:11,200 --> 02:41:14,399 Thou shalt not add my speed 4109 02:41:14,399 --> 02:41:16,040 to the speed of light. 4110 02:41:16,040 --> 02:41:17,640 Also, no material object can 4111 02:41:17,640 --> 02:41:21,000 travel at or beyond the speed of light. 4112 02:41:21,000 --> 02:41:21,880 There's nothing in physics 4113 02:41:21,880 --> 02:41:23,040 that prevents you from traveling 4114 02:41:23,040 --> 02:41:24,240 as close to the speed of 4115 02:41:24,240 --> 02:41:25,240 light as you like. 4116 02:41:25,240 --> 02:41:29,319 99.9% the speed of light is just fine. 4117 02:41:29,319 --> 02:41:31,200 But no matter how hard you try, 4118 02:41:31,200 --> 02:41:33,160 you can never gain that last 4119 02:41:33,160 --> 02:41:34,760 decimal point. 4120 02:41:34,760 --> 02:41:36,320 For the world to be logically 4121 02:41:36,319 --> 02:41:37,319 consistent, 4122 02:41:37,319 --> 02:41:41,319 there must be a cosmic speed limit. 4123 02:41:41,319 --> 02:41:42,920 The most bizarre aspect of 4124 02:41:42,920 --> 02:41:44,680 traveling near the speed of light 4125 02:41:44,680 --> 02:41:47,880 is that time slows down. 4126 02:41:47,880 --> 02:41:50,560 All clocks, mechanical and biological, 4127 02:41:50,560 --> 02:41:52,360 tick more slowly near the 4128 02:41:52,359 --> 02:41:53,599 speed of light. 4129 02:41:53,600 --> 02:41:55,400 But stationary clocks tick at 4130 02:41:55,399 --> 02:41:57,200 their usual rate. 4131 02:41:57,200 --> 02:41:58,519 If we travel close to light 4132 02:41:58,520 --> 02:42:01,041 speed, we age more slowly 4133 02:42:01,040 --> 02:42:07,120 than those we left behind. 4134 02:42:07,120 --> 02:42:10,680 Today, we have preliminary 4135 02:42:10,680 --> 02:42:13,520 designs of ships which will 4136 02:42:13,520 --> 02:42:16,480 take people to the stars. 4137 02:42:16,479 --> 02:42:18,439 They are constructed in Earth 4138 02:42:18,439 --> 02:42:22,319 orbit, and from there, they 4139 02:42:22,319 --> 02:42:24,479 venture on their great 4140 02:42:24,479 --> 02:42:26,759 interstellar journeys. 4141 02:42:26,760 --> 02:42:32,720 One of them is called Project Orion. 4142 02:42:32,720 --> 02:42:34,960 It utilizes nuclear weapons, 4143 02:42:34,960 --> 02:42:37,680 hydrogen bombs, against an 4144 02:42:37,680 --> 02:42:39,520 inertial plate, 4145 02:42:39,520 --> 02:42:41,201 each explosion providing a 4146 02:42:41,200 --> 02:42:44,240 kind of putt-putt of vast 4147 02:42:44,240 --> 02:42:47,760 nuclear motorboat in space. 4148 02:42:47,760 --> 02:42:51,360 Orion seems entirely practical 4149 02:42:51,359 --> 02:42:52,279 and was under serious 4150 02:42:52,279 --> 02:42:54,120 development in the United States 4151 02:42:54,120 --> 02:42:56,120 until the signing of the 4152 02:42:56,120 --> 02:42:58,120 international treaty forbidding 4153 02:42:58,120 --> 02:43:01,080 nuclear weapons explosions in space. 4154 02:43:01,080 --> 02:43:06,359 Orion might go 10% the speed of light. 4155 02:43:06,359 --> 02:43:08,519 So a trip to Alpha Centauri, 4156 02:43:08,520 --> 02:43:10,081 four and a half light years 4157 02:43:10,080 --> 02:43:12,200 away, would take 45 years, 4158 02:43:12,200 --> 02:43:14,760 less than a human lifetime. 4159 02:43:14,760 --> 02:43:16,280 Such ships could not travel 4160 02:43:16,279 --> 02:43:18,599 close enough to the speed of light 4161 02:43:18,600 --> 02:43:20,440 for the time-slowing effects 4162 02:43:20,439 --> 02:43:22,000 of special relativity to 4163 02:43:22,000 --> 02:43:24,120 become important. 4164 02:43:24,120 --> 02:43:26,000 It does not seem likely that 4165 02:43:26,000 --> 02:43:27,560 such ships would be built 4166 02:43:27,560 --> 02:43:29,840 before the middle of the 21st century, 4167 02:43:29,840 --> 02:43:31,520 although we could build an 4168 02:43:31,520 --> 02:43:34,000 Orion starship now. 4169 02:43:34,000 --> 02:43:35,920 For voyages beyond the nearest 4170 02:43:35,920 --> 02:43:38,319 stars, something must be added. 4171 02:43:38,319 --> 02:43:39,519 Perhaps they could be used as 4172 02:43:39,520 --> 02:43:41,840 multi-generation ships, 4173 02:43:41,840 --> 02:43:43,800 so those arriving would be 4174 02:43:43,800 --> 02:43:45,200 the remote descendants of 4175 02:43:45,200 --> 02:43:46,519 those who had originally set 4176 02:43:46,520 --> 02:43:49,360 out centuries before. 4177 02:43:49,359 --> 02:43:51,359 Or perhaps some safe means of 4178 02:43:51,359 --> 02:43:53,559 human hibernation might be found, 4179 02:43:53,560 --> 02:43:54,800 so that the space travelers 4180 02:43:54,800 --> 02:43:56,640 might be frozen and then 4181 02:43:56,640 --> 02:43:59,000 bought out when they arrive 4182 02:43:59,000 --> 02:44:02,520 at the destination centuries later. 4183 02:44:02,520 --> 02:44:04,121 But fast interstellar space 4184 02:44:04,120 --> 02:44:05,840 flight, approaching the speed 4185 02:44:05,840 --> 02:44:09,080 of light, is much more difficult. 4186 02:44:09,080 --> 02:44:10,880 That's an objective not for a 4187 02:44:10,880 --> 02:44:12,560 hundred years, but for a 4188 02:44:12,560 --> 02:44:15,320 thousand, or for ten thousand. 4189 02:44:15,319 --> 02:44:19,040 But it also is possible. 4190 02:44:20,160 --> 02:44:22,279 A kind of interstellar ramjet 4191 02:44:22,279 --> 02:44:23,399 has been proposed, 4192 02:44:23,399 --> 02:44:25,200 which scoops up the hydrogen 4193 02:44:25,200 --> 02:44:28,279 atoms which float between the stars, 4194 02:44:28,279 --> 02:44:29,519 accelerates them into an 4195 02:44:29,520 --> 02:44:33,241 engine, and spits them out the back. 4196 02:44:33,240 --> 02:44:34,840 For most of the trip, the 4197 02:44:34,840 --> 02:44:36,279 velocity would be very close 4198 02:44:36,279 --> 02:44:37,679 to the speed of light, 4199 02:44:37,680 --> 02:44:41,160 and time would slow down enormously. 4200 02:44:41,160 --> 02:44:43,599 By how much? 4201 02:44:43,600 --> 02:44:45,760 Barnard's star could be 4202 02:44:45,760 --> 02:44:47,280 reached by such a ship 4203 02:44:47,279 --> 02:44:50,479 in eight years' ship time. 4204 02:44:50,479 --> 02:44:51,679 The center of the Milky Way 4205 02:44:51,680 --> 02:44:54,640 galaxy in 21 years. 4206 02:44:54,640 --> 02:44:59,161 The Andromeda galaxy in 28 years. 4207 02:44:59,160 --> 02:45:00,439 Of course, the people left 4208 02:45:00,439 --> 02:45:01,200 behind on the Earth 4209 02:45:01,200 --> 02:45:03,760 would see things somewhat differently. 4210 02:45:03,760 --> 02:45:05,040 Instead of 21 years to the 4211 02:45:05,040 --> 02:45:06,000 center of the galaxy, 4212 02:45:06,000 --> 02:45:09,760 they would measure it as 30,000 years. 4213 02:45:09,760 --> 02:45:11,880 When we got back, very few 4214 02:45:11,880 --> 02:45:12,720 of our friends would 4215 02:45:12,720 --> 02:45:15,640 be around to greet us. 4216 02:45:15,640 --> 02:45:17,600 In principle, such a journey, 4217 02:45:17,600 --> 02:45:19,880 mounting the decimal points closer 4218 02:45:19,880 --> 02:45:21,080 and closer to the speed of 4219 02:45:21,080 --> 02:45:23,600 light, would even permit us 4220 02:45:23,600 --> 02:45:26,121 to circumnavigate the known universe 4221 02:45:26,120 --> 02:45:30,080 in 56 years ship time. 4222 02:45:30,080 --> 02:45:32,600 We would return tens of 4223 02:45:32,600 --> 02:45:35,320 billions of years in the far 4224 02:45:35,319 --> 02:45:37,880 future with the Earth a 4225 02:45:37,880 --> 02:45:43,120 charred cinder and the Sun dead. 4226 02:45:43,120 --> 02:45:44,160 Relativistic space 4227 02:45:44,160 --> 02:45:45,840 flight makes the universe 4228 02:45:45,840 --> 02:45:47,360 accessible to advanced 4229 02:45:47,359 --> 02:45:50,399 civilizations but only to those 4230 02:45:50,399 --> 02:45:51,759 who go on the journey, not 4231 02:45:51,760 --> 02:45:55,000 to those who stay home. 4232 02:45:55,000 --> 02:45:59,279 These designs are probably further 4233 02:45:59,279 --> 02:46:01,120 from the actual interstellar 4234 02:46:01,120 --> 02:46:04,399 spacecraft of the future 4235 02:46:04,399 --> 02:46:07,200 than Leonardo's models are 4236 02:46:07,200 --> 02:46:09,160 from the supersonic transports 4237 02:46:09,160 --> 02:46:11,160 of the present. 4238 02:46:11,160 --> 02:46:13,240 But if we do not destroy ourselves, 4239 02:46:13,240 --> 02:46:15,399 I believe that we will one 4240 02:46:15,399 --> 02:46:18,719 day venture to the stars. 4241 02:46:18,720 --> 02:46:21,600 When our solar system is all explored, 4242 02:46:21,600 --> 02:46:46,520 the planets of other stars will beckon. 4243 02:46:46,520 --> 02:46:47,880 Even when our descendants are 4244 02:46:47,880 --> 02:46:49,680 established on near-Earth 4245 02:46:49,680 --> 02:46:51,760 asteroids and Mars 4246 02:46:51,760 --> 02:46:52,800 and the Moons of the outer 4247 02:46:52,800 --> 02:46:56,000 solar system and the Kuiper comet belt, 4248 02:46:56,000 --> 02:47:00,399 it still won't be entirely safe. 4249 02:47:00,399 --> 02:47:02,960 In the long run, the Sun may 4250 02:47:02,960 --> 02:47:05,120 generate stupendous X-ray and 4251 02:47:05,120 --> 02:47:07,840 ultraviolet outbursts. 4252 02:47:07,840 --> 02:47:09,200 The solar system will enter 4253 02:47:09,200 --> 02:47:11,399 one of the vast interstellar clouds 4254 02:47:11,399 --> 02:47:13,240 lurking nearby, and the 4255 02:47:13,240 --> 02:47:16,519 planets will darken and cool. 4256 02:47:16,520 --> 02:47:17,640 A shower of deadly 4257 02:47:17,640 --> 02:47:19,241 comets will come roaring out 4258 02:47:19,240 --> 02:47:21,200 of the Oort cloud, threatening 4259 02:47:21,200 --> 02:47:25,479 civilizations on many adjacent worlds. 4260 02:47:25,479 --> 02:47:26,879 We will recognize that a 4261 02:47:26,880 --> 02:47:28,760 nearby star is about to 4262 02:47:28,760 --> 02:47:31,480 become a supernova. 4263 02:47:31,479 --> 02:47:34,000 And in the really long run, 4264 02:47:34,000 --> 02:47:35,920 the Sun, on its way to 4265 02:47:35,920 --> 02:47:36,920 becoming a red giant 4266 02:47:36,920 --> 02:47:40,960 star will get bigger and brighter. 4267 02:47:40,960 --> 02:47:42,080 The Earth will begin to lose 4268 02:47:42,080 --> 02:47:45,000 its air and water to space. 4269 02:47:45,000 --> 02:47:47,359 The soil will char. 4270 02:47:47,359 --> 02:47:50,319 The oceans will evaporate and boil. 4271 02:47:50,319 --> 02:47:53,599 The rocks will vaporize. And our 4272 02:47:53,600 --> 02:47:55,680 planet may even be swallowed 4273 02:47:55,680 --> 02:47:59,120 up into the interior of the Sun. 4274 02:47:59,120 --> 02:48:02,640 Far from being made for us, eventually 4275 02:48:02,640 --> 02:48:04,280 the solar system will become 4276 02:48:04,279 --> 02:48:06,800 too dangerous for us. 4277 02:48:06,800 --> 02:48:08,840 In the long run, putting 4278 02:48:08,840 --> 02:48:10,160 all our eggs in a single 4279 02:48:10,160 --> 02:48:12,760 stellar basket, no matter how 4280 02:48:12,760 --> 02:48:13,880 reliable the solar system 4281 02:48:13,880 --> 02:48:17,840 has been lately, may be too risky. 4282 02:48:17,840 --> 02:48:19,880 In the long run, as 4283 02:48:19,880 --> 02:48:21,560 Tsiolkovsky and Goddard 4284 02:48:21,560 --> 02:48:24,000 long ago recognized, we need 4285 02:48:24,000 --> 02:48:28,600 to leave the solar system. 4286 02:48:28,600 --> 02:48:31,400 Such a future would, I think, 4287 02:48:31,399 --> 02:48:33,120 naturally evolve by slow 4288 02:48:33,120 --> 02:48:35,720 increments, even without any 4289 02:48:35,720 --> 02:48:38,480 grand goal of interstellar travel. 4290 02:48:38,479 --> 02:48:39,799 Here's how it might work. 4291 02:48:39,800 --> 02:48:42,560 For safety, some communities may 4292 02:48:42,560 --> 02:48:44,280 wish to sever their ties with 4293 02:48:44,279 --> 02:48:46,399 the rest of humanity, 4294 02:48:46,399 --> 02:48:47,599 uninfluenced by other 4295 02:48:47,600 --> 02:48:50,960 societies, other ethical codes, 4296 02:48:50,960 --> 02:48:54,279 other technological imperatives. 4297 02:48:54,279 --> 02:48:55,559 In a time when comets and 4298 02:48:55,560 --> 02:48:57,081 asteroids are being routinely 4299 02:48:57,080 --> 02:48:58,800 repositioned, we will 4300 02:48:58,800 --> 02:49:00,240 be able to populate a small 4301 02:49:00,240 --> 02:49:03,319 world and then cut it loose. 4302 02:49:03,319 --> 02:49:05,799 In successive generations, as 4303 02:49:05,800 --> 02:49:08,600 this world sped outward, the 4304 02:49:08,600 --> 02:49:10,920 Earth would fade from bright 4305 02:49:10,920 --> 02:49:15,840 star to pale dot to invisibility. 4306 02:49:15,840 --> 02:49:17,800 The Sun would appear dimmer 4307 02:49:17,800 --> 02:49:19,040 until it was no more than a 4308 02:49:19,040 --> 02:49:21,760 vaguely yellow point of light lost 4309 02:49:21,760 --> 02:49:25,640 among thousands of others. 4310 02:49:25,640 --> 02:49:28,480 The travelers would approach 4311 02:49:28,479 --> 02:49:31,639 interstellar night. 4312 02:49:31,640 --> 02:49:33,201 Some such communities may be 4313 02:49:33,200 --> 02:49:35,519 content with occasional radio 4314 02:49:35,520 --> 02:49:36,920 and laser traffic with 4315 02:49:36,920 --> 02:49:39,239 the old home worlds. 4316 02:49:39,239 --> 02:49:41,559 Others, confident of the 4317 02:49:41,560 --> 02:49:43,280 superiority of their own survival 4318 02:49:43,279 --> 02:49:45,920 chances and wary of 4319 02:49:45,920 --> 02:49:48,640 contamination, may try to disappear. 4320 02:49:49,680 --> 02:49:50,680 Perhaps all contact 4321 02:49:50,680 --> 02:49:52,000 with them will ultimately be 4322 02:49:52,000 --> 02:49:59,560 lost, their very existence forgotten. 4323 02:49:59,560 --> 02:50:00,720 Even the resources of a 4324 02:50:00,720 --> 02:50:02,680 sizeable asteroid or comet are 4325 02:50:02,680 --> 02:50:06,480 finite, and eventually more resources 4326 02:50:06,479 --> 02:50:08,919 must be sought elsewhere, 4327 02:50:08,920 --> 02:50:10,399 especially water needed for 4328 02:50:10,399 --> 02:50:13,000 drink, for a breathable oxygen 4329 02:50:13,000 --> 02:50:15,319 atmosphere and for hydrogen to 4330 02:50:15,319 --> 02:50:17,759 power fusion reactors. 4331 02:50:17,760 --> 02:50:20,040 So, in the long run, these 4332 02:50:20,040 --> 02:50:22,399 communities must migrate from 4333 02:50:22,399 --> 02:50:24,719 world to world with no lasting 4334 02:50:24,720 --> 02:50:27,840 loyalty to any. 4335 02:50:27,840 --> 02:50:31,120 We might call it pioneering 4336 02:50:31,120 --> 02:50:33,640 or homesteading. 4337 02:50:33,640 --> 02:50:34,960 A less sympathetic observer 4338 02:50:34,960 --> 02:50:36,800 might describe it as sucking 4339 02:50:36,800 --> 02:50:38,400 dry the resources of little 4340 02:50:38,399 --> 02:50:41,120 world after little world. 4341 02:50:41,120 --> 02:50:43,080 But there are a trillion 4342 02:50:43,080 --> 02:50:46,680 little worlds in the Oort Comet Cloud. 4343 02:50:46,680 --> 02:50:48,640 Living in small numbers on a 4344 02:50:48,640 --> 02:50:51,240 modest stepmother world, far 4345 02:50:51,239 --> 02:50:52,960 from the Sun, we will know that 4346 02:50:52,960 --> 02:50:54,640 every scrap of food and every 4347 02:50:54,640 --> 02:50:57,560 drop of water is dependent on 4348 02:50:57,560 --> 02:50:59,000 the smooth operation of a 4349 02:50:59,000 --> 02:51:02,279 farsighted technology. 4350 02:51:02,279 --> 02:51:03,840 But these conditions are not 4351 02:51:03,840 --> 02:51:05,160 radically unlike those to 4352 02:51:05,160 --> 02:51:08,200 which we are already accustomed. 4353 02:51:08,200 --> 02:51:09,720 Digging resources out of the 4354 02:51:09,720 --> 02:51:12,800 ground and stalking passing 4355 02:51:12,800 --> 02:51:17,520 resources seems oddly familiar, 4356 02:51:17,520 --> 02:51:21,560 like a forgotten memory of childhood. 4357 02:51:21,560 --> 02:51:24,480 It is, with a few significant 4358 02:51:24,479 --> 02:51:27,160 changes, the strategy of our 4359 02:51:27,160 --> 02:51:29,960 hunter-gatherer ancestors. 4360 02:51:29,960 --> 02:51:32,480 For 99.9% of the tenure of 4361 02:51:32,479 --> 02:51:36,040 humans on Earth we lived such a life. 4362 02:51:36,040 --> 02:51:37,399 Judging from some of the last 4363 02:51:37,399 --> 02:51:39,359 surviving hunter-gatherers, just 4364 02:51:39,359 --> 02:51:41,279 before they were engulfed by 4365 02:51:41,279 --> 02:51:43,960 the present global civilization, 4366 02:51:43,960 --> 02:51:46,680 we may have been relatively happy. 4367 02:51:46,680 --> 02:51:48,520 It's the kind of life that forged us. 4368 02:51:50,160 --> 02:51:54,000 So, after a brief, only 4369 02:51:54,000 --> 02:51:56,800 partially successful, sedentary 4370 02:51:56,800 --> 02:51:59,120 experiment, we may become 4371 02:51:59,120 --> 02:52:01,800 wanderers again. 4372 02:52:01,800 --> 02:52:03,600 More technological than last 4373 02:52:03,600 --> 02:52:05,920 time, but even then, our 4374 02:52:05,920 --> 02:52:07,600 technology, stone tools and 4375 02:52:07,600 --> 02:52:10,320 fire was our only hedge 4376 02:52:10,319 --> 02:52:13,759 against extinction. 4377 02:52:13,760 --> 02:52:15,239 I don't know where my train 4378 02:52:15,239 --> 02:52:17,359 of argument ends. 4379 02:52:17,359 --> 02:52:18,519 As more time passes, 4380 02:52:19,479 --> 02:52:21,839 attractive new denizens of the 4381 02:52:21,840 --> 02:52:24,560 cosmic zoo will draw us 4382 02:52:24,560 --> 02:52:25,660 further outward, 4383 02:52:25,660 --> 02:52:27,440 hard, and increasingly 4384 02:52:27,439 --> 02:52:28,479 improbable and deadly 4385 02:52:28,479 --> 02:52:31,839 catastrophes must come to pass. 4386 02:52:31,840 --> 02:52:33,400 The probabilities are 4387 02:52:33,399 --> 02:52:36,120 cumulative, but as time goes 4388 02:52:36,120 --> 02:52:37,720 on, technological species will 4389 02:52:37,720 --> 02:52:38,400 also accrue 4390 02:52:38,399 --> 02:52:40,479 greater and greater powers, 4391 02:52:40,479 --> 02:52:42,839 far surpassing any we can 4392 02:52:42,840 --> 02:52:45,400 imagine today. 4393 02:52:45,399 --> 02:52:47,319 Perhaps if we're very 4394 02:52:47,319 --> 02:52:50,040 skillful—lucky, I think, won't 4395 02:52:50,040 --> 02:52:52,640 be enough—we will ultimately 4396 02:52:52,640 --> 02:52:55,480 spread far from home, sailing 4397 02:52:55,479 --> 02:52:58,200 through the starry archipelagos 4398 02:52:58,200 --> 02:53:02,960 of the vast Milky Way galaxy. 4399 02:53:02,960 --> 02:53:05,160 Even a modest extrapolation of 4400 02:53:05,160 --> 02:53:06,439 our recent advances in 4401 02:53:06,439 --> 02:53:10,120 transportation suggests that in 4402 02:53:10,120 --> 02:53:12,319 only a few centuries we will 4403 02:53:12,319 --> 02:53:13,639 be able to travel close to 4404 02:53:13,640 --> 02:53:16,320 the speed of light. 4405 02:53:16,319 --> 02:53:18,439 Perhaps this is hopelessly optimistic. 4406 02:53:19,359 --> 02:53:20,599 Perhaps it will really take 4407 02:53:20,600 --> 02:53:23,520 millennia or more. 4408 02:53:23,520 --> 02:53:26,280 But unless we destroy ourselves first, 4409 02:53:26,279 --> 02:53:27,719 we will be inventing new 4410 02:53:27,720 --> 02:53:31,240 technologies as strange to us, 4411 02:53:31,239 --> 02:53:33,359 as Voyager might be to our 4412 02:53:33,359 --> 02:53:35,719 hunter-gatherer ancestors. 4413 02:53:35,720 --> 02:53:38,280 Even today we can think of ways, 4414 02:53:38,279 --> 02:53:41,719 clumsy, ruinously expensive, 4415 02:53:41,720 --> 02:53:43,960 inefficient to be sure, 4416 02:53:43,960 --> 02:53:45,920 of constructing a starship 4417 02:53:45,920 --> 02:53:48,680 that approaches light speed. 4418 02:53:48,680 --> 02:53:51,280 In time, the designs will 4419 02:53:51,279 --> 02:53:53,359 become more elegant, more 4420 02:53:53,359 --> 02:53:57,000 affordable, more efficient. 4421 02:53:57,000 --> 02:53:59,200 The day will come when we 4422 02:53:59,200 --> 02:54:00,639 overcome the necessity of 4423 02:54:00,640 --> 02:54:04,000 jumping from comet to comet, 4424 02:54:04,000 --> 02:54:04,880 we will begin 4425 02:54:04,880 --> 02:54:06,279 to soar through the light 4426 02:54:06,279 --> 02:54:09,639 years and, as St. 4427 02:54:09,640 --> 02:54:12,080 Augustine said of the gods of the 4428 02:54:12,080 --> 02:54:17,519 ancient Greeks and Romans, colonize the sky. 4429 02:54:17,520 --> 02:54:19,440 Such descendants may be tens 4430 02:54:19,439 --> 02:54:21,120 or hundreds of generations 4431 02:54:21,120 --> 02:54:24,000 removed from anyone who ever lived 4432 02:54:24,000 --> 02:54:26,920 on the surface of a planet. 4433 02:54:26,920 --> 02:54:27,920 Their cultures will be 4434 02:54:27,920 --> 02:54:30,440 different, their technologies 4435 02:54:30,439 --> 02:54:33,000 far advanced, their languages 4436 02:54:33,000 --> 02:54:34,720 changed, their 4437 02:54:34,720 --> 02:54:35,920 association with machine 4438 02:54:35,920 --> 02:54:37,040 intelligence much more 4439 02:54:37,040 --> 02:54:39,760 intimate, perhaps their very 4440 02:54:39,760 --> 02:54:40,920 appearances 4441 02:54:40,920 --> 02:54:44,520 markedly altered from that of 4442 02:54:44,520 --> 02:54:46,041 their nearly mythical ancestors 4443 02:54:46,040 --> 02:54:48,760 who first tentatively set forth in the 4444 02:54:48,760 --> 02:54:51,040 late 20th century into the 4445 02:54:51,040 --> 02:54:53,479 sea of space. 4446 02:54:53,479 --> 02:54:55,080 But they will be human, at 4447 02:54:55,080 --> 02:54:57,479 least in large part. They will 4448 02:54:57,479 --> 02:55:00,599 be practitioners of high technology. 4449 02:55:00,600 --> 02:55:04,000 They will have historical records. 4450 02:55:04,000 --> 02:55:06,040 Despite Augustine's 4451 02:55:06,040 --> 02:55:11,080 judgment on Lot's wife that 4452 02:55:11,080 --> 02:55:12,840 no one who is being saved 4453 02:55:12,840 --> 02:55:15,760 should long for what he is leaving. 4454 02:55:15,760 --> 02:55:18,320 They will not wholly forget the Earth. 4455 02:55:21,359 --> 02:55:23,559 In modern western society, 4456 02:55:23,560 --> 02:55:24,920 writes the scholar Charles 4457 02:55:24,920 --> 02:55:29,319 Lindholm, the erosion of tradition 4458 02:55:29,319 --> 02:55:30,719 and the collapse of accepted 4459 02:55:30,720 --> 02:55:33,960 religious belief leaves us 4460 02:55:33,960 --> 02:55:37,640 without a telos, an end to which 4461 02:55:37,640 --> 02:55:41,360 we strive, a sanctified notion 4462 02:55:41,359 --> 02:55:44,359 of humanity's potential. 4463 02:55:44,359 --> 02:55:47,239 Bereft of a sacred project, 4464 02:55:47,239 --> 02:55:48,920 we have only a demystified 4465 02:55:48,920 --> 02:55:51,880 image of a frail and fallible 4466 02:55:51,880 --> 02:55:55,440 humanity no longer capable of 4467 02:55:55,439 --> 02:55:57,319 becoming godlike." 4468 02:55:59,040 --> 02:56:01,920 I believe it's healthy, indeed 4469 02:56:01,920 --> 02:56:03,920 essential, to keep our frailty 4470 02:56:03,920 --> 02:56:05,239 and fallibility firmly 4471 02:56:05,239 --> 02:56:07,359 in mind, and I worry about 4472 02:56:07,359 --> 02:56:10,519 people who aspire to be god-like. 4473 02:56:10,520 --> 02:56:13,000 But as for a long-term goal, 4474 02:56:13,000 --> 02:56:15,200 and a sacred project, there 4475 02:56:15,200 --> 02:56:17,559 is one before us. 4476 02:56:17,560 --> 02:56:20,000 On it, the very survival of 4477 02:56:20,000 --> 02:56:22,040 our species depends. 4478 02:56:22,040 --> 02:56:23,399 If we've been locked and 4479 02:56:23,399 --> 02:56:25,559 bolted into a prison of the 4480 02:56:25,560 --> 02:56:30,240 self, here is an escape hatch. 4481 02:56:30,239 --> 02:56:33,279 something worthy, something 4482 02:56:33,279 --> 02:56:35,759 vastly larger than ourselves, 4483 02:56:35,760 --> 02:56:40,200 a crucial act on behalf of humanity. 4484 02:56:40,200 --> 02:56:42,880 Peopling other worlds unifies 4485 02:56:42,880 --> 02:56:44,880 nations and ethnic groups, 4486 02:56:44,880 --> 02:56:46,960 binds the generations, 4487 02:56:46,960 --> 02:56:49,480 and requires us to be both 4488 02:56:49,479 --> 02:56:52,000 smart and wise. 4489 02:56:52,000 --> 02:56:56,239 It liberates our nature and, in part, 4490 02:56:56,239 --> 02:56:58,880 returns us to our beginnings. 4491 02:56:58,880 --> 02:57:03,080 Even now, this new telos is 4492 02:57:03,080 --> 02:57:18,160 within our grasp. 4493 02:57:36,600 --> 02:57:38,960 In 1633, the Roman Catholic 4494 02:57:38,960 --> 02:57:41,040 Church condemned Galileo for 4495 02:57:41,040 --> 02:57:42,040 teaching that the Earth goes 4496 02:57:42,040 --> 02:57:44,040 around the Sun. 4497 02:57:44,040 --> 02:57:45,160 Let's take a closer look at 4498 02:57:45,160 --> 02:57:47,599 this famous controversy. 4499 02:57:47,600 --> 02:57:48,960 In the preface to his 4500 02:57:48,960 --> 02:57:50,399 book comparing the two 4501 02:57:50,399 --> 02:57:52,719 hypotheses, an Earth-centered 4502 02:57:52,720 --> 02:57:54,680 and a Sun-centered universe, 4503 02:57:54,680 --> 02:57:55,860 Galileo had written 4504 02:57:55,860 --> 02:57:58,720 In these words, the celestial 4505 02:57:58,720 --> 02:58:01,000 phenomena will be examined, 4506 02:58:01,000 --> 02:58:02,439 strengthening the Copernican 4507 02:58:02,439 --> 02:58:04,799 hypothesis until it might seem 4508 02:58:04,800 --> 02:58:08,239 that this must triumph absolutely. 4509 02:58:08,239 --> 02:58:09,319 And later in the book he 4510 02:58:09,319 --> 02:58:11,840 confessed, Nor can I ever 4511 02:58:11,840 --> 02:58:13,720 sufficiently admire Copernicus 4512 02:58:13,720 --> 02:58:15,480 and his followers. 4513 02:58:15,479 --> 02:58:16,959 They have, through sheer force 4514 02:58:16,960 --> 02:58:18,840 of intellect, done such 4515 02:58:18,840 --> 02:58:21,080 violence to their own senses as 4516 02:58:21,080 --> 02:58:22,760 to prefer what reason told 4517 02:58:22,760 --> 02:58:24,720 them over what sensible 4518 02:58:24,720 --> 02:58:28,480 experience plainly showed them. 4519 02:58:28,479 --> 02:58:30,279 The Church declared, in its 4520 02:58:30,279 --> 02:58:33,439 indictment of Galileo, the 4521 02:58:33,439 --> 02:58:34,960 doctrine that the Earth is neither 4522 02:58:34,960 --> 02:58:36,640 the center of the universe 4523 02:58:36,640 --> 02:58:39,161 nor immovable, but moves even 4524 02:58:39,160 --> 02:58:42,439 with a daily rotation, is absurd, 4525 02:58:42,439 --> 02:58:44,080 and both psychologically and 4526 02:58:44,080 --> 02:58:46,359 theologically false, and at 4527 02:58:46,359 --> 02:58:50,960 the least an error of faith. 4528 02:58:50,960 --> 02:58:53,680 Galileo replied, The doctrine 4529 02:58:53,680 --> 02:58:54,960 of the movements of the Earth 4530 02:58:54,960 --> 02:58:57,239 and the fixity of the Sun is 4531 02:58:57,239 --> 02:58:58,599 condemned on the ground that 4532 02:58:58,600 --> 02:59:00,000 the scriptures speak in many 4533 02:59:00,000 --> 02:59:01,800 places of the Sun moving and 4534 02:59:01,800 --> 02:59:04,800 the Earth standing still. 4535 02:59:04,800 --> 02:59:06,279 It is piously spoken that the 4536 02:59:06,279 --> 02:59:08,719 scriptures cannot lie, but 4537 02:59:08,720 --> 02:59:10,680 none will deny that they are frequently 4538 02:59:10,680 --> 02:59:12,400 abstruse and their true 4539 02:59:12,399 --> 02:59:14,319 meaning difficult to discover 4540 02:59:14,319 --> 02:59:17,679 and more than the bare words signify. 4541 02:59:17,680 --> 02:59:18,640 I think that in the 4542 02:59:18,640 --> 02:59:20,680 discussion of natural problems 4543 02:59:20,680 --> 02:59:22,520 we ought to begin not with 4544 02:59:22,520 --> 02:59:23,800 the Scriptures, 4545 02:59:23,800 --> 02:59:25,239 but with experiments 4546 02:59:25,239 --> 02:59:28,479 and demonstrations. 4547 02:59:28,479 --> 02:59:31,080 But in his recantation on 4548 02:59:31,080 --> 02:59:34,519 June 22, 1633, Galileo was 4549 02:59:34,520 --> 02:59:37,280 made to say these words, 4550 02:59:37,279 --> 02:59:38,559 having been admonished 4551 02:59:38,560 --> 02:59:40,440 by the Holy Office entirely 4552 02:59:40,439 --> 02:59:42,719 to abandon the false opinion 4553 02:59:42,720 --> 02:59:43,720 that the Sun was the center 4554 02:59:43,720 --> 02:59:46,040 of the universe and immovable, 4555 02:59:46,040 --> 02:59:47,000 and that the Earth was not 4556 02:59:47,000 --> 02:59:48,200 the center of the same, and 4557 02:59:48,200 --> 02:59:50,279 that it moved, I have been 4558 02:59:50,279 --> 02:59:53,439 suspected of heresy, that is, 4559 02:59:53,439 --> 02:59:55,879 of having held and believed that 4560 02:59:55,880 --> 02:59:56,920 the Sun is the center of the 4561 02:59:56,920 --> 02:59:58,760 universe and immovable, and 4562 02:59:58,760 --> 02:59:59,880 that the Earth is not the center 4563 02:59:59,880 --> 03:00:03,000 of the same, and that it does move. 4564 03:00:03,000 --> 03:00:06,359 I abjure with a sincere heart 4565 03:00:06,359 --> 03:00:08,599 and unfeigned faith. 4566 03:00:08,600 --> 03:00:12,000 I curse and detest the same 4567 03:00:12,000 --> 03:00:14,479 errors and heresies, and 4568 03:00:14,479 --> 03:00:17,319 generally all and every error and sect 4569 03:00:17,319 --> 03:00:21,120 contrary to the Holy Catholic Church. 4570 03:00:21,120 --> 03:00:23,760 It took the Church until 1832 4571 03:00:23,760 --> 03:00:25,360 to remove Galileo's work from 4572 03:00:25,359 --> 03:00:27,559 its list of books which Catholics 4573 03:00:27,560 --> 03:00:29,600 were forbidden to read at the 4574 03:00:29,600 --> 03:00:31,400 risk of dire punishment of 4575 03:00:31,399 --> 03:00:34,279 their immortal souls. 4576 03:00:34,279 --> 03:00:35,679 To its credit, although 4577 03:00:35,680 --> 03:00:38,160 belatedly and reluctantly, the 4578 03:00:38,160 --> 03:00:40,319 Church in 1992 repudiated its 4579 03:00:40,319 --> 03:00:42,799 denunciation of Galileo. 4580 03:00:42,800 --> 03:00:44,000 It still cannot quite bring 4581 03:00:44,000 --> 03:00:45,120 itself, though, to see the 4582 03:00:45,120 --> 03:00:47,439 significance of its opposition. 4583 03:00:47,439 --> 03:00:49,639 In a 1992 speech, Pope John 4584 03:00:49,640 --> 03:00:53,161 Paul II argued as follows. 4585 03:00:53,160 --> 03:00:54,279 From the beginning of the Age 4586 03:00:54,279 --> 03:00:56,120 of Enlightenment, he said, 4587 03:00:56,120 --> 03:00:58,479 down to our own day, the Galileo 4588 03:00:58,479 --> 03:00:59,799 case has been a sort of 4589 03:00:59,800 --> 03:01:01,800 myth, in which the image 4590 03:01:01,800 --> 03:01:04,080 fabricated out of the events is quite 4591 03:01:04,080 --> 03:01:06,359 far removed from reality. 4592 03:01:06,359 --> 03:01:08,040 In this perspective, the 4593 03:01:08,040 --> 03:01:09,479 Galileo case was a symbol of 4594 03:01:09,479 --> 03:01:11,399 the Catholic Church's supposed 4595 03:01:11,399 --> 03:01:12,719 rejection of scientific 4596 03:01:12,720 --> 03:01:15,440 progress, or of dogmatic 4597 03:01:15,439 --> 03:01:17,519 obscurantism opposed to the 4598 03:01:17,520 --> 03:01:18,280 free search for 4599 03:01:18,279 --> 03:01:19,040 truth." 4600 03:01:21,960 --> 03:01:23,040 But surely the Holy 4601 03:01:23,040 --> 03:01:24,920 Inquisition, ushering the 4602 03:01:24,920 --> 03:01:27,600 elderly and infirm Galileo in 4603 03:01:27,600 --> 03:01:28,480 to inspect 4604 03:01:28,479 --> 03:01:30,200 the instruments of torture in 4605 03:01:30,200 --> 03:01:32,319 the dungeons of the Church 4606 03:01:32,319 --> 03:01:35,000 not only admits, but requires 4607 03:01:35,000 --> 03:01:37,439 just such an interpretation. 4608 03:01:37,439 --> 03:01:39,519 This was not mere scientific 4609 03:01:39,520 --> 03:01:41,800 caution and restraint, a 4610 03:01:41,800 --> 03:01:43,000 reluctance to shift the 4611 03:01:43,000 --> 03:01:44,920 paradigm until compelling 4612 03:01:44,920 --> 03:01:46,600 evidence such as the annual 4613 03:01:46,600 --> 03:01:48,080 parallax was available. 4614 03:01:48,080 --> 03:01:49,479 This was fear of discussion 4615 03:01:49,479 --> 03:01:51,639 and debate, censoring 4616 03:01:51,640 --> 03:01:53,400 alternative views and 4617 03:01:53,399 --> 03:01:54,479 threatening to torture 4618 03:01:54,479 --> 03:01:57,359 their proponents, betray a 4619 03:01:57,359 --> 03:01:58,559 lack of faith in the very 4620 03:01:58,560 --> 03:02:00,161 doctrine and parishioners that are 4621 03:02:00,160 --> 03:02:02,519 ostensibly being protected? 4622 03:02:02,520 --> 03:02:04,201 Why were threats and Galileo's 4623 03:02:04,200 --> 03:02:05,920 house arrest needed? 4624 03:02:05,920 --> 03:02:08,279 Can a truth defend itself in 4625 03:02:08,279 --> 03:02:11,639 its confrontation with error? 4626 03:02:11,640 --> 03:02:12,800 The Pope does, though, go on 4627 03:02:12,800 --> 03:02:16,360 to add, The error of the 4628 03:02:16,359 --> 03:02:18,880 theologians of the time, when they 4629 03:02:18,880 --> 03:02:20,200 maintained the centrality of 4630 03:02:20,200 --> 03:02:22,160 the Earth, was to think that 4631 03:02:22,160 --> 03:02:23,399 our understanding of the physical 4632 03:02:23,399 --> 03:02:24,759 world structure was in some 4633 03:02:24,760 --> 03:02:27,440 way imposed by the literal 4634 03:02:27,439 --> 03:02:29,239 sense of sacred scriptures." 4635 03:02:31,520 --> 03:02:32,560 But if the Bible is not 4636 03:02:32,560 --> 03:02:34,560 everywhere literally true, 4637 03:02:34,560 --> 03:02:36,880 which parts are divinely inspired and 4638 03:02:36,880 --> 03:02:39,800 which are merely fallible and human? 4639 03:02:39,800 --> 03:02:40,840 As soon as we admit that 4640 03:02:40,840 --> 03:02:43,160 there are scriptural mistakes 4641 03:02:43,160 --> 03:02:45,239 or concessions to the ignorance of 4642 03:02:45,239 --> 03:02:47,319 the times, then how can the 4643 03:02:47,319 --> 03:02:49,239 Bible be an inerrant guide to 4644 03:02:49,239 --> 03:02:51,239 ethics and morals? 4645 03:02:51,239 --> 03:02:53,120 Might sects and individuals 4646 03:02:53,120 --> 03:02:54,559 now accept as authentic the 4647 03:02:54,560 --> 03:02:56,560 parts of the Bible they like, 4648 03:02:56,560 --> 03:02:58,000 and reject those that are 4649 03:02:58,000 --> 03:03:01,680 inconvenient or burdensome? 4650 03:03:01,680 --> 03:03:03,360 We lack consensus about our 4651 03:03:03,359 --> 03:03:05,120 place in the universe. 4652 03:03:05,120 --> 03:03:06,399 There is no generally 4653 03:03:06,399 --> 03:03:08,759 agreed-upon, long-term vision 4654 03:03:08,760 --> 03:03:11,800 of the goal of our species, other than 4655 03:03:11,800 --> 03:03:14,600 perhaps simple survival. 4656 03:03:14,600 --> 03:03:15,760 Especially when times are 4657 03:03:15,760 --> 03:03:17,960 hard, we become desperate for 4658 03:03:17,960 --> 03:03:20,560 encouragement, unreceptive to 4659 03:03:20,560 --> 03:03:22,360 the litany of great demotions 4660 03:03:22,359 --> 03:03:24,639 and dashed hopes, and much 4661 03:03:24,640 --> 03:03:26,240 more willing to hear that 4662 03:03:26,239 --> 03:03:27,239 we're special, 4663 03:03:27,239 --> 03:03:28,519 never mind if the evidence is 4664 03:03:28,520 --> 03:03:30,560 paper thin. 4665 03:03:30,560 --> 03:03:31,840 If it takes a little myth 4666 03:03:31,840 --> 03:03:33,279 and ritual to get us through 4667 03:03:33,279 --> 03:03:35,880 a night that seems endless, who 4668 03:03:35,880 --> 03:03:37,920 among us cannot sympathize 4669 03:03:37,920 --> 03:03:39,480 and understand? 4670 03:03:39,479 --> 03:03:40,959 But if our objective is deep 4671 03:03:40,960 --> 03:03:42,720 knowledge rather than shallow 4672 03:03:42,720 --> 03:03:45,200 reassurance, the gains from this 4673 03:03:45,200 --> 03:03:46,920 new perspective far outweigh 4674 03:03:46,920 --> 03:03:47,720 the losses. 4675 03:03:47,720 --> 03:03:48,640 circumstances. 4676 03:03:48,640 --> 03:03:49,800 The scientific revolution 4677 03:03:49,800 --> 03:03:51,040 permitted us to glimpse an 4678 03:03:51,040 --> 03:03:53,600 underlying, ordered universe in 4679 03:03:53,600 --> 03:03:55,040 which there was a literal 4680 03:03:55,040 --> 03:03:56,880 harmony of the worlds. 4681 03:03:56,880 --> 03:03:58,680 If we understand nature, there 4682 03:03:58,680 --> 03:03:59,960 is a prospect of controlling 4683 03:03:59,960 --> 03:04:01,960 it, or at least mitigating 4684 03:04:01,960 --> 03:04:03,399 the harm it may bring. 4685 03:04:03,399 --> 03:04:06,200 In this sense, science brought hope. 4686 03:04:06,200 --> 03:04:07,160 Most of the great 4687 03:04:07,160 --> 03:04:08,519 deprovincializing debates were 4688 03:04:08,520 --> 03:04:09,840 entered into with no thought 4689 03:04:09,840 --> 03:04:12,560 for their practical implications. 4690 03:04:12,560 --> 03:04:14,201 Passionate and curious humans 4691 03:04:14,200 --> 03:04:15,239 wish to understand their 4692 03:04:15,239 --> 03:04:17,040 actual circumstances, 4693 03:04:17,040 --> 03:04:18,840 how unique or pedestrian they 4694 03:04:18,840 --> 03:04:20,640 in their world are, 4695 03:04:20,640 --> 03:04:22,560 their ultimate origins and 4696 03:04:22,560 --> 03:04:26,000 destinies, how the universe works. 4697 03:04:26,000 --> 03:04:27,960 Surprisingly, some of these 4698 03:04:27,960 --> 03:04:29,600 debates have yielded the most 4699 03:04:29,600 --> 03:04:31,560 profound practical benefits. 4700 03:04:31,560 --> 03:04:32,520 The very method of 4701 03:04:32,520 --> 03:04:33,920 mathematical reasoning that 4702 03:04:33,920 --> 03:04:35,080 Isaac Newton introduced 4703 03:04:35,080 --> 03:04:36,600 to explain the motion of the 4704 03:04:36,600 --> 03:04:38,480 planets around the Sun 4705 03:04:38,479 --> 03:04:39,599 has led to most of the 4706 03:04:39,600 --> 03:04:42,440 technology of our modern world. 4707 03:04:42,439 --> 03:04:44,359 The Industrial Revolution, for 4708 03:04:44,359 --> 03:04:46,080 all its shortcomings, 4709 03:04:46,080 --> 03:04:47,920 is still the global model of 4710 03:04:47,920 --> 03:04:49,440 how an agricultural nation can 4711 03:04:49,439 --> 03:04:51,439 emerge from poverty. 4712 03:04:51,439 --> 03:04:53,000 These debates have 4713 03:04:53,000 --> 03:04:57,279 bread-and-butter consequences. 4714 03:04:57,279 --> 03:04:59,840 It might have been otherwise. 4715 03:04:59,840 --> 03:05:01,360 It might have been that the 4716 03:05:01,359 --> 03:05:03,799 balance lay elsewhere, 4717 03:05:03,800 --> 03:05:05,360 that humans by and large did 4718 03:05:05,359 --> 03:05:06,799 not want to know about a 4719 03:05:06,800 --> 03:05:08,060 disquieting universe, 4720 03:05:08,060 --> 03:05:09,000 universe, that we were 4721 03:05:09,000 --> 03:05:10,560 unwilling to permit challenges 4722 03:05:10,560 --> 03:05:13,121 to the prevailing wisdom. 4723 03:05:13,120 --> 03:05:14,960 Despite determined resistance 4724 03:05:14,960 --> 03:05:16,960 in every age, it is very 4725 03:05:16,960 --> 03:05:18,720 much to our credit that we have 4726 03:05:18,720 --> 03:05:20,120 allowed ourselves to follow 4727 03:05:20,120 --> 03:05:21,800 the evidence, to draw 4728 03:05:21,800 --> 03:05:22,920 conclusions that at first 4729 03:05:22,920 --> 03:05:24,680 seemed daunting. 4730 03:05:24,680 --> 03:05:26,120 A universe so much larger and 4731 03:05:26,120 --> 03:05:28,040 older, that our personal and 4732 03:05:28,040 --> 03:05:29,279 historical experience is 4733 03:05:29,279 --> 03:05:31,439 dwarfed and humbled. 4734 03:05:31,439 --> 03:05:33,160 A universe in which every day 4735 03:05:33,160 --> 03:05:35,040 suns are born and worlds 4736 03:05:35,040 --> 03:05:37,040 obliterated, a universe in which 4737 03:05:37,040 --> 03:05:40,880 humanity, newly arrived, clings 4738 03:05:40,880 --> 03:05:44,720 to an obscure clod of matter. 4739 03:05:44,720 --> 03:05:46,400 In everyday life we often 4740 03:05:46,399 --> 03:05:49,160 sense, in the bedrooms of 4741 03:05:49,160 --> 03:05:52,639 teenagers or in national politics, that 4742 03:05:52,640 --> 03:05:55,440 chaos is natural and order 4743 03:05:55,439 --> 03:05:58,160 imposed from above. 4744 03:05:58,160 --> 03:05:59,120 While there are deeper 4745 03:05:59,120 --> 03:06:00,519 irregularities in the universe 4746 03:06:00,520 --> 03:06:02,201 than the simple circumstances we 4747 03:06:02,200 --> 03:06:04,319 generally described as orderly, 4748 03:06:04,319 --> 03:06:05,799 all that order, simple and 4749 03:06:05,800 --> 03:06:08,279 complex, seems to derive from laws 4750 03:06:08,279 --> 03:06:10,080 of nature established at the 4751 03:06:10,080 --> 03:06:12,960 Big Bang, or maybe earlier, 4752 03:06:12,960 --> 03:06:14,080 rather than as a consequence 4753 03:06:14,080 --> 03:06:16,760 of belated intervention by an 4754 03:06:16,760 --> 03:06:17,560 imperfect deity. 4755 03:06:19,319 --> 03:06:20,679 God is to be found in the 4756 03:06:20,680 --> 03:06:23,160 details, is the famous dictum 4757 03:06:23,160 --> 03:06:26,319 of the German scholar Aby Warburg. 4758 03:06:26,319 --> 03:06:28,399 But, amid much elegance and 4759 03:06:28,399 --> 03:06:30,879 precision, the details of life 4760 03:06:30,880 --> 03:06:32,560 in the universe also exhibit 4761 03:06:32,560 --> 03:06:34,640 haphazard, jury-rigged 4762 03:06:34,640 --> 03:06:38,000 arrangements and much poor planning. 4763 03:06:38,000 --> 03:06:39,840 What shall we make of this? 4764 03:06:39,840 --> 03:06:42,239 An edifice abandoned early in 4765 03:06:42,239 --> 03:06:44,639 construction by the architect? 4766 03:06:44,640 --> 03:06:45,680 The evidence, so far at 4767 03:06:45,680 --> 03:06:47,040 least, and laws of nature 4768 03:06:47,040 --> 03:06:50,560 aside, does not require a designer. 4769 03:06:50,560 --> 03:06:52,040 Maybe there's one hiding, 4770 03:06:52,040 --> 03:06:55,200 maddeningly unwilling to be revealed. 4771 03:06:55,200 --> 03:07:17,519 Sometimes it seems a very slender hope. 4772 03:07:22,359 --> 03:07:24,719 The cosmic calendar compresses 4773 03:07:24,720 --> 03:07:25,680 the local history of the 4774 03:07:25,680 --> 03:07:28,520 universe into a single year. 4775 03:07:28,520 --> 03:07:29,800 If the universe began on 4776 03:07:29,800 --> 03:07:32,160 January 1st, it was not until 4777 03:07:32,160 --> 03:07:35,519 May that the Milky Way formed. 4778 03:07:35,520 --> 03:07:37,121 Other planetary systems may 4779 03:07:37,120 --> 03:07:41,559 have appeared in June, July and August, 4780 03:07:41,560 --> 03:07:42,800 but our Sun and Earth not 4781 03:07:42,800 --> 03:07:44,560 until mid-September. 4782 03:07:44,560 --> 03:07:47,800 Life arose soon after. 4783 03:07:47,800 --> 03:07:49,000 Everything humans have ever 4784 03:07:49,000 --> 03:07:51,080 done occurred in that bright 4785 03:07:51,080 --> 03:07:52,319 speck at the 4786 03:07:52,319 --> 03:07:57,759 lower right of the cosmic calendar. 4787 03:07:57,760 --> 03:07:59,320 The Big Bang is at upper 4788 03:07:59,319 --> 03:08:00,519 left in the first 4789 03:08:00,520 --> 03:08:02,920 second of January 1st. 4790 03:08:02,920 --> 03:08:05,359 Fifteen billion years later is 4791 03:08:05,359 --> 03:08:07,319 our present time, the last 4792 03:08:07,319 --> 03:08:15,279 second of December 31st. 4793 03:08:15,279 --> 03:08:16,800 Every month is one and a 4794 03:08:16,800 --> 03:08:18,640 quarter billion years long. 4795 03:08:18,640 --> 03:08:21,760 Each day represents 40 million years. 4796 03:08:21,760 --> 03:08:23,600 Each second stands for some 4797 03:08:23,600 --> 03:08:25,920 500 years of our history, the 4798 03:08:25,920 --> 03:08:28,600 blinking of an eye in the drama 4799 03:08:28,600 --> 03:08:35,320 of cosmic time. 4800 03:08:35,319 --> 03:08:37,200 At this scale, the cosmic 4801 03:08:37,200 --> 03:08:38,639 calendar is the size of a 4802 03:08:38,640 --> 03:08:40,800 football field, but all of human 4803 03:08:40,800 --> 03:08:43,320 history would occupy an area 4804 03:08:43,319 --> 03:08:45,080 the size of my hand. 4805 03:08:45,080 --> 03:08:46,840 We're just beginning to trace the 4806 03:08:46,840 --> 03:08:49,080 long and tortuous path which 4807 03:08:49,080 --> 03:08:50,640 began with the primeval 4808 03:08:50,640 --> 03:08:52,560 fireball and led to the 4809 03:08:52,560 --> 03:08:55,121 condensation of matter, gas, 4810 03:08:55,120 --> 03:08:57,720 dust, stars, galaxies, and at 4811 03:08:57,720 --> 03:08:58,720 least in our little 4812 03:08:58,720 --> 03:09:00,600 nook of the universe, planets 4813 03:09:00,600 --> 03:09:02,840 and life, intelligence and 4814 03:09:02,840 --> 03:09:04,520 inquisitive men and women. 4815 03:09:04,520 --> 03:09:05,520 We've emerged so 4816 03:09:05,520 --> 03:09:07,041 recently that the familiar 4817 03:09:07,040 --> 03:09:08,519 events of our recorded history 4818 03:09:08,520 --> 03:09:10,640 occupy only the last seconds 4819 03:09:10,640 --> 03:09:14,000 of the last minute of December 31st. 4820 03:09:14,000 --> 03:09:15,279 Some critical events for the 4821 03:09:15,279 --> 03:09:16,599 human species, however, began 4822 03:09:16,600 --> 03:09:20,000 much earlier, minutes earlier. 4823 03:09:20,000 --> 03:09:22,160 The secrets of evolution are 4824 03:09:22,160 --> 03:09:25,439 time and death, time for the 4825 03:09:25,439 --> 03:09:27,239 slow accumulation of favorable 4826 03:09:27,239 --> 03:09:30,200 mutations and death to make 4827 03:09:30,200 --> 03:09:32,960 room for new species. 4828 03:09:32,960 --> 03:09:34,160 Life on Earth arose in 4829 03:09:34,160 --> 03:09:36,359 September of the cosmic calendar... 4830 03:09:36,359 --> 03:09:37,759 ...when our world, still 4831 03:09:37,760 --> 03:09:39,480 heavily battered and cratered 4832 03:09:39,479 --> 03:09:41,359 from its violent origin... 4833 03:09:41,359 --> 03:09:42,080 ...may have looked a little 4834 03:09:42,080 --> 03:09:45,640 like the Moon. 4835 03:09:45,640 --> 03:09:47,320 The Earth is about four and 4836 03:09:47,319 --> 03:09:49,359 a half billion years old. 4837 03:09:49,359 --> 03:09:51,239 In the cosmic calendar, it 4838 03:09:51,239 --> 03:09:53,679 condensed out of interstellar 4839 03:09:53,680 --> 03:09:55,120 gas and dust... 4840 03:09:55,120 --> 03:09:57,920 ...around September 14th. 4841 03:09:57,920 --> 03:09:58,880 We know from the fossil 4842 03:09:58,880 --> 03:09:59,920 record that the origin of 4843 03:09:59,920 --> 03:10:01,880 life happened soon afterwards... 4844 03:10:01,880 --> 03:10:04,319 ...maybe around September 25th, 4845 03:10:04,319 --> 03:10:05,359 something like that... 4846 03:10:05,359 --> 03:10:06,880 ...probably in the ponds and 4847 03:10:06,880 --> 03:10:09,319 oceans of the primitive Earth. 4848 03:10:09,319 --> 03:10:10,319 Now, the first living things 4849 03:10:10,319 --> 03:10:12,679 were not anything so complex 4850 03:10:12,680 --> 03:10:14,320 as a one-celled organism... 4851 03:10:14,319 --> 03:10:15,920 ...which already is a highly 4852 03:10:15,920 --> 03:10:17,319 sophisticated form of life. 4853 03:10:18,080 --> 03:10:20,160 No, the first stirrings of 4854 03:10:20,160 --> 03:10:22,239 life were much more humble... 4855 03:10:22,239 --> 03:10:25,359 ...and happened on the molecular level. 4856 03:10:25,359 --> 03:10:27,239 In those early days, lightning 4857 03:10:27,239 --> 03:10:29,559 and ultraviolet light from the Sun... 4858 03:10:29,560 --> 03:10:31,240 ...were breaking apart simple 4859 03:10:31,239 --> 03:10:32,719 hydrogen-rich molecules in the 4860 03:10:32,720 --> 03:10:34,120 primitive atmosphere... 4861 03:10:34,120 --> 03:10:35,599 ...and the fragments of the 4862 03:10:35,600 --> 03:10:36,480 molecules were 4863 03:10:36,479 --> 03:10:38,799 spontaneously recombining... 4864 03:10:38,800 --> 03:10:40,279 ...into more and more 4865 03:10:40,279 --> 03:10:44,880 complex molecules. 4866 03:10:44,880 --> 03:10:46,279 The products of this early 4867 03:10:46,279 --> 03:10:48,880 chemistry dissolved in the oceans... 4868 03:10:48,880 --> 03:10:51,640 ...forming a kind of organic 4869 03:10:51,640 --> 03:10:53,120 soup of gradually 4870 03:10:53,120 --> 03:10:54,880 increasing complexity... 4871 03:10:54,880 --> 03:10:58,720 ...until one day, quite by accident... 4872 03:10:58,720 --> 03:11:00,320 ...a molecule arose which was 4873 03:11:00,319 --> 03:11:02,200 able to make crude copies of 4874 03:11:02,200 --> 03:11:03,800 itself, using as building 4875 03:11:03,800 --> 03:11:06,800 blocks the other molecules in the soup. 4876 03:11:06,800 --> 03:11:10,400 This was the ancestor of DNA, 4877 03:11:10,399 --> 03:11:13,920 the master molecule of life on Earth. 4878 03:11:13,920 --> 03:11:14,880 It's made of four different 4879 03:11:14,880 --> 03:11:16,359 molecular parts called 4880 03:11:16,359 --> 03:11:19,120 nucleotides, which constitute the four 4881 03:11:19,120 --> 03:11:21,479 letters of the genetic code, 4882 03:11:21,479 --> 03:11:23,519 the language of heredity. 4883 03:11:23,520 --> 03:11:26,000 Each of the four nucleotides, 4884 03:11:26,000 --> 03:11:28,520 the rungs on the DNA ladder, 4885 03:11:28,520 --> 03:11:31,081 are a different color in this model. 4886 03:11:31,080 --> 03:11:32,120 The instructions that are 4887 03:11:32,120 --> 03:11:33,640 spelled out are different for 4888 03:11:33,640 --> 03:11:34,480 different organisms. 4889 03:11:34,479 --> 03:11:37,160 That's why organisms are different. 4890 03:11:37,160 --> 03:11:40,239 Now, a mutation is a change 4891 03:11:40,239 --> 03:11:41,200 of a nucleotide, 4892 03:11:41,200 --> 03:11:42,840 a misspelling of the 4893 03:11:42,840 --> 03:11:44,400 genetic instructions. 4894 03:11:44,399 --> 03:11:46,160 Most mutations spell genetic 4895 03:11:46,160 --> 03:11:47,720 nonsense, as you'd expect, 4896 03:11:47,720 --> 03:11:49,400 because they're random. 4897 03:11:49,399 --> 03:11:50,479 They're harmful for the 4898 03:11:50,479 --> 03:11:51,799 next generation. 4899 03:11:51,800 --> 03:11:53,560 ...but a very few, by 4900 03:11:53,560 --> 03:11:55,240 accident, make better sense 4901 03:11:55,239 --> 03:11:56,639 than the original instructions... 4902 03:11:56,640 --> 03:11:59,600 ...and aid the evolution of life. 4903 03:11:59,600 --> 03:12:02,680 DNA is about a billion times 4904 03:12:02,680 --> 03:12:04,920 smaller than we see it here. 4905 03:12:04,920 --> 03:12:06,480 In fact, each of these things 4906 03:12:06,479 --> 03:12:07,279 that looks like a piece of 4907 03:12:07,279 --> 03:12:10,239 fruit is an atom. 4908 03:12:10,239 --> 03:12:11,920 Without the tools of science, 4909 03:12:11,920 --> 03:12:13,760 the machinery of life would 4910 03:12:13,760 --> 03:12:17,160 be invisible. 4911 03:12:19,439 --> 03:12:21,759 Four billion years ago, the 4912 03:12:21,760 --> 03:12:23,320 ancestors of DNA were 4913 03:12:23,319 --> 03:12:25,559 competing for molecular building blocks 4914 03:12:25,560 --> 03:12:28,640 and leaving crude copies of themselves. 4915 03:12:28,640 --> 03:12:30,240 There were no predators, the 4916 03:12:30,239 --> 03:12:32,160 stuff of life was everywhere, 4917 03:12:32,160 --> 03:12:33,599 so the oceans and the murky 4918 03:12:33,600 --> 03:12:35,680 pools that filled the craters 4919 03:12:35,680 --> 03:12:37,600 were for these molecules a 4920 03:12:37,600 --> 03:12:39,400 Garden of Eden. 4921 03:12:39,399 --> 03:12:41,040 With reproduction, mutation and 4922 03:12:41,040 --> 03:12:42,680 natural selection, the 4923 03:12:42,680 --> 03:12:44,880 evolution of living molecules 4924 03:12:44,880 --> 03:12:47,279 was well underway. 4925 03:12:47,279 --> 03:12:49,800 Varieties with specialized functions 4926 03:12:49,800 --> 03:12:51,760 then joined together, making a 4927 03:12:51,760 --> 03:12:52,880 collective, 4928 03:12:52,880 --> 03:12:54,600 the first cell. 4929 03:12:54,600 --> 03:12:56,240 The organic soup eventually 4930 03:12:56,239 --> 03:12:57,760 ate itself up. 4931 03:12:57,760 --> 03:13:00,320 But by this time, plants had evolved, 4932 03:13:00,319 --> 03:13:01,639 able to use sunlight to make 4933 03:13:01,640 --> 03:13:03,440 their own building blocks. 4934 03:13:03,439 --> 03:13:06,160 They turned the waters green. 4935 03:13:06,160 --> 03:13:07,519 A number of one-celled plants 4936 03:13:07,520 --> 03:13:08,640 joined together, 4937 03:13:08,640 --> 03:13:13,240 the first multicellular organisms. 4938 03:13:13,239 --> 03:13:14,880 Equally important was the 4939 03:13:14,880 --> 03:13:16,600 invention, not made until 4940 03:13:16,600 --> 03:13:19,080 early November, of sex. 4941 03:13:19,080 --> 03:13:25,120 It was stumbled upon by the microbes. 4942 03:13:25,120 --> 03:13:27,040 By December 1st, green plants 4943 03:13:27,040 --> 03:13:28,920 had released copious amounts 4944 03:13:28,920 --> 03:13:30,960 of oxygen and nitrogen into 4945 03:13:30,960 --> 03:13:32,399 the atmosphere. 4946 03:13:32,399 --> 03:13:37,080 The sky is made by life. 4947 03:13:37,080 --> 03:13:39,800 Then, suddenly, on December 15th, 4948 03:13:39,800 --> 03:13:40,680 there was an enormous 4949 03:13:40,680 --> 03:13:43,080 proliferation of new life forms, 4950 03:13:43,080 --> 03:13:47,040 an event called the Cambrian Explosion. 4951 03:13:51,160 --> 03:13:53,279 By December 18th, there were 4952 03:13:53,279 --> 03:13:55,279 vast herds of trilobites 4953 03:13:55,279 --> 03:13:57,759 foraging on the ocean bottom, 4954 03:13:57,760 --> 03:13:59,440 and squid-like creatures with 4955 03:13:59,439 --> 03:14:01,319 their multicolored shells 4956 03:14:01,319 --> 03:14:05,759 were everywhere. 4957 03:14:05,760 --> 03:14:06,960 We know enough to sketch in 4958 03:14:06,960 --> 03:14:09,439 a few of the subsequent details, 4959 03:14:09,439 --> 03:14:10,799 The first fish and the first 4960 03:14:10,800 --> 03:14:13,520 vertebrates appeared on December 19th. 4961 03:14:13,520 --> 03:14:15,041 Plants began to colonize the 4962 03:14:15,040 --> 03:14:17,279 land on December 20th. 4963 03:14:17,279 --> 03:14:18,639 The first winged insects 4964 03:14:18,640 --> 03:14:21,520 fluttered by on December 22nd. 4965 03:14:21,520 --> 03:14:23,041 And on this date also, there 4966 03:14:23,040 --> 03:14:24,880 were the first amphibians, 4967 03:14:24,880 --> 03:14:27,560 creatures something like the lungfish, 4968 03:14:27,560 --> 03:14:29,640 able to survive both on land 4969 03:14:29,640 --> 03:14:30,960 and in water. 4970 03:14:30,960 --> 03:14:33,080 Our direct ancestors were now 4971 03:14:33,080 --> 03:14:38,120 leaving the oceans behind. 4972 03:14:38,120 --> 03:14:40,160 The first trees and the first 4973 03:14:40,160 --> 03:14:42,399 reptiles evolved on December 4974 03:14:42,399 --> 03:14:44,439 23rd, two amazing 4975 03:14:44,439 --> 03:14:47,040 evolutionary developments. 4976 03:14:48,840 --> 03:14:50,680 We're descended from some of 4977 03:14:50,680 --> 03:14:56,760 those reptiles. 4978 03:14:56,760 --> 03:14:58,720 The dinosaurs appeared on 4979 03:14:58,720 --> 03:15:00,200 Christmas Eve. 4980 03:15:00,200 --> 03:15:00,960 There were many different 4981 03:15:00,960 --> 03:15:02,560 kinds of dinosaurs. 4982 03:15:02,560 --> 03:15:08,680 The Earth was once their planet. 4983 03:15:08,680 --> 03:15:10,280 Many stood upright and had 4984 03:15:10,279 --> 03:15:12,319 some fair intelligence. 4985 03:15:12,319 --> 03:15:14,239 Great lizards crashed and 4986 03:15:14,239 --> 03:15:16,960 thundered through the steaming jungles. 4987 03:15:22,239 --> 03:15:24,000 Unnoticed by the dinosaurs, a 4988 03:15:24,000 --> 03:15:25,000 new creature, 4989 03:15:25,000 --> 03:15:26,399 whose young were born live 4990 03:15:26,399 --> 03:15:27,399 and helpless, 4991 03:15:27,399 --> 03:15:29,960 was making its timid debut. 4992 03:15:29,960 --> 03:15:31,760 The first mammals emerged on 4993 03:15:31,760 --> 03:15:33,239 December 26th, 4994 03:15:33,239 --> 03:15:39,840 the first birds on the following day. 4995 03:15:39,840 --> 03:15:41,680 But the dinosaurs still 4996 03:15:41,680 --> 03:15:43,560 dominated the planet. 4997 03:15:43,560 --> 03:15:45,320 Then, suddenly, without 4998 03:15:45,319 --> 03:15:46,920 warning, all over the planet at once, 4999 03:15:47,600 --> 03:15:49,600 the dinosaurs died. 5000 03:15:49,600 --> 03:15:51,520 The cause is unknown, but the 5001 03:15:51,520 --> 03:15:53,000 lesson is clear. 5002 03:15:53,000 --> 03:15:55,080 Even 160 million years on a 5003 03:15:55,080 --> 03:15:58,040 planet is no guarantee of survival. 5004 03:15:58,040 --> 03:16:00,120 The dinosaurs perished around 5005 03:16:00,120 --> 03:16:04,359 the time of the first flower. 5006 03:16:04,359 --> 03:16:06,120 On December 30th, the first 5007 03:16:06,120 --> 03:16:07,760 creatures who looked even a 5008 03:16:07,760 --> 03:16:09,880 little bit human evolved, 5009 03:16:09,880 --> 03:16:11,640 accompanied by a spectacular 5010 03:16:11,640 --> 03:16:14,161 increase in the size of their brains. 5011 03:16:14,160 --> 03:16:15,920 ...and then, on the evening 5012 03:16:15,920 --> 03:16:17,480 of the last day of the last 5013 03:16:17,479 --> 03:16:19,279 month, only a few million years 5014 03:16:19,279 --> 03:16:22,000 ago, the first true humans 5015 03:16:22,000 --> 03:16:23,520 took their place on the 5016 03:16:23,520 --> 03:16:31,400 cosmic calendar. 5017 03:16:31,399 --> 03:16:33,199 We humans appear on the 5018 03:16:33,199 --> 03:16:35,720 cosmic calendar so recently 5019 03:16:35,720 --> 03:16:37,720 that our recorded history occupies 5020 03:16:37,720 --> 03:16:40,360 only the last few seconds of 5021 03:16:40,359 --> 03:16:44,000 the last minute of December 31st. 5022 03:16:44,000 --> 03:16:46,279 in the vast ocean of time 5023 03:16:46,279 --> 03:16:49,000 which this calendar represents. 5024 03:16:49,000 --> 03:16:54,520 All our memories are confined 5025 03:16:54,520 --> 03:16:57,280 to this small square. 5026 03:16:57,279 --> 03:16:59,000 Every person we've ever heard 5027 03:16:59,000 --> 03:17:02,439 of lived somewhere in there. 5028 03:17:02,439 --> 03:17:04,759 All those kings and battles, 5029 03:17:04,760 --> 03:17:06,440 migrations and inventions, 5030 03:17:06,439 --> 03:17:08,439 wars and loves, everything in 5031 03:17:08,439 --> 03:17:09,879 the history books 5032 03:17:09,880 --> 03:17:12,920 This happens here, in the 5033 03:17:12,920 --> 03:17:16,840 last 10 seconds of the cosmic calendar. 5034 03:17:21,359 --> 03:17:22,960 We on Earth have just 5035 03:17:22,960 --> 03:17:25,359 awakened to the great oceans 5036 03:17:25,359 --> 03:17:27,439 of space and time from which 5037 03:17:27,439 --> 03:17:30,399 we have emerged. 5038 03:17:30,399 --> 03:17:33,120 We are the legacy of 15 5039 03:17:33,120 --> 03:17:36,199 billion years of cosmic evolution. 5040 03:17:36,199 --> 03:17:38,160 We have a choice. 5041 03:17:38,160 --> 03:17:39,760 We can enhance life and come 5042 03:17:39,760 --> 03:17:40,720 to know the universe that 5043 03:17:40,720 --> 03:17:42,960 made us, or we can squander 5044 03:17:42,960 --> 03:17:43,600 our 15 billion 5045 03:17:43,600 --> 03:17:45,560 billion year heritage in 5046 03:17:45,560 --> 03:17:49,480 meaningless self-destruction. 5047 03:17:49,479 --> 03:17:50,599 What happens in the first 5048 03:17:50,600 --> 03:17:52,040 second of the next cosmic 5049 03:17:52,040 --> 03:17:55,519 year depends on what we do here and 5050 03:17:55,520 --> 03:17:58,440 now with our intelligence and 5051 03:17:58,439 --> 03:18:16,759 our knowledge of the cosmos. 5052 03:18:41,239 --> 03:18:46,319 There are an enormous number of stars. 5053 03:18:46,319 --> 03:18:47,679 Only some of them will have 5054 03:18:47,680 --> 03:18:51,560 planets suitable for life. 5055 03:18:51,560 --> 03:18:53,121 On only some of those worlds 5056 03:18:53,120 --> 03:18:56,760 will intelligence arise, and 5057 03:18:56,760 --> 03:18:58,760 perhaps a few of those civilizations 5058 03:18:58,760 --> 03:19:01,040 will avoid the trap jointly 5059 03:19:01,040 --> 03:19:03,239 set by their technology and 5060 03:19:03,239 --> 03:19:06,399 their passions. 5061 03:19:06,399 --> 03:19:07,199 If there are many 5062 03:19:07,199 --> 03:19:08,720 civilizations, one of them 5063 03:19:08,720 --> 03:19:12,199 should be rather close by. 5064 03:19:12,199 --> 03:19:13,040 If there are few 5065 03:19:13,040 --> 03:19:15,600 civilizations, then even the 5066 03:19:15,600 --> 03:19:18,920 nearest may be very far away. 5067 03:19:18,920 --> 03:19:21,279 So, if civilizations do not 5068 03:19:21,279 --> 03:19:22,960 always destroy themselves 5069 03:19:22,960 --> 03:19:24,560 shortly after discovering radio 5070 03:19:24,560 --> 03:19:27,560 astronomy, then the sky may 5071 03:19:27,560 --> 03:19:29,640 be softly humming with 5072 03:19:29,640 --> 03:19:32,680 messages from the stars, with signals 5073 03:19:32,680 --> 03:19:34,360 from civilizations enormously 5074 03:19:34,359 --> 03:19:39,920 older and wiser than we. 5075 03:19:39,920 --> 03:19:41,199 If there are millions of 5076 03:19:41,199 --> 03:19:42,599 technical civilizations in the 5077 03:19:42,600 --> 03:19:44,320 Milky Way, each capable of 5078 03:19:44,319 --> 03:19:45,759 radio astronomy, 5079 03:19:45,760 --> 03:19:51,520 how far away is the nearest one? 5080 03:19:51,520 --> 03:19:52,960 If they're distributed more or 5081 03:19:52,960 --> 03:19:55,080 less randomly through space, 5082 03:19:55,080 --> 03:19:56,559 then the nearest one will be 5083 03:19:56,560 --> 03:19:59,200 some 200 light years away. 5084 03:19:59,199 --> 03:20:01,160 But within 200 light years, 5085 03:20:01,160 --> 03:20:02,680 there are hundreds of 5086 03:20:02,680 --> 03:20:04,560 thousands of stars. 5087 03:20:04,560 --> 03:20:06,081 To find the needle in this 5088 03:20:06,080 --> 03:20:08,680 haystack requires a dedicated 5089 03:20:08,680 --> 03:20:14,520 and systematic search. 5090 03:20:14,520 --> 03:20:15,760 There are many cosmic radio 5091 03:20:15,760 --> 03:20:17,520 sources having nothing to do 5092 03:20:17,520 --> 03:20:18,960 with intelligent life. 5093 03:20:18,960 --> 03:20:20,640 So, how would we know that 5094 03:20:20,640 --> 03:20:27,480 we were receiving a message? 5095 03:20:27,479 --> 03:20:28,959 The transmitting civilization 5096 03:20:28,960 --> 03:20:30,080 could make it very easy for 5097 03:20:30,080 --> 03:20:32,319 us, if they wished. 5098 03:20:32,319 --> 03:20:33,920 Imagine we're in the course 5099 03:20:33,920 --> 03:20:36,399 of a systematic search, or in 5100 03:20:36,399 --> 03:20:38,080 the midst of some more conventional 5101 03:20:38,080 --> 03:20:41,120 radio observations, and suppose 5102 03:20:41,120 --> 03:20:43,439 one day we find a strong 5103 03:20:43,439 --> 03:20:45,479 signal slowly emerging, not 5104 03:20:45,479 --> 03:20:48,000 just some background hiss, but 5105 03:20:48,000 --> 03:20:56,319 a methodical series of pulses. 5106 03:20:56,319 --> 03:21:00,639 The numbers 1, 2, 3, 5, 7, 5107 03:21:00,640 --> 03:21:04,240 11, 13, a signal made of 5108 03:21:04,239 --> 03:21:06,800 prime numbers, numbers divisible only 5109 03:21:06,800 --> 03:21:12,840 by one and themselves. 5110 03:21:12,840 --> 03:21:14,000 There is no natural 5111 03:21:14,000 --> 03:21:15,399 astrophysical process that 5112 03:21:15,399 --> 03:21:16,559 generates prime numbers. 5113 03:21:17,279 --> 03:21:19,160 we would have to conclude 5114 03:21:19,160 --> 03:21:20,720 that someone fond of 5115 03:21:20,720 --> 03:21:22,800 elementary mathematics was 5116 03:21:22,800 --> 03:21:31,080 saying hello. 5117 03:21:31,080 --> 03:21:32,559 This would be no more than a 5118 03:21:32,560 --> 03:21:34,960 beacon to attract our attention. 5119 03:21:34,960 --> 03:21:37,480 The main message will be subtler, 5120 03:21:37,479 --> 03:21:40,160 more hidden, far richer. 5121 03:21:40,160 --> 03:21:42,559 We may have to work hard to find it. 5122 03:21:42,560 --> 03:21:44,560 Think of the glories of an 5123 03:21:44,560 --> 03:21:46,600 An exotic civilization far 5124 03:21:46,600 --> 03:21:48,320 more advanced than we, 5125 03:21:48,319 --> 03:21:50,319 collected by the great radio 5126 03:21:50,319 --> 03:21:52,679 telescopes of Earth. 5127 03:21:52,680 --> 03:21:54,200 The receipt of an interstellar 5128 03:21:54,199 --> 03:21:55,559 message would be one of the 5129 03:21:55,560 --> 03:21:57,720 major events in human history, 5130 03:21:57,720 --> 03:21:59,440 and the beginning of the 5131 03:21:59,439 --> 03:22:03,359 deprovincialization of our planet. 5132 03:22:03,359 --> 03:22:05,719 A serious and systematic radio 5133 03:22:05,720 --> 03:22:07,360 search for extraterrestrial 5134 03:22:07,359 --> 03:22:11,000 civilizations may come soon. 5135 03:22:11,000 --> 03:22:13,199 It's comparatively inexpensive. 5136 03:22:13,199 --> 03:22:15,160 A search taking decades would 5137 03:22:15,160 --> 03:22:18,359 cost less than the budget overruns 5138 03:22:18,359 --> 03:22:20,239 on a single modest weapons 5139 03:22:20,239 --> 03:22:24,120 system in a single year. 5140 03:22:24,120 --> 03:22:25,680 But whether there are only a 5141 03:22:25,680 --> 03:22:27,080 few advanced galactic 5142 03:22:27,080 --> 03:22:30,840 civilizations or millions, shouldn't 5143 03:22:30,840 --> 03:22:38,440 some of them have voyaged to Earth? 5144 03:22:38,439 --> 03:22:39,559 There are many possible 5145 03:22:39,560 --> 03:22:40,920 answers, including the 5146 03:22:40,920 --> 03:22:43,239 contention that they have come here. 5147 03:22:43,239 --> 03:22:45,479 Although Well the evidence for that is 5148 03:22:45,479 --> 03:22:46,439 pitifully slim. 5149 03:22:48,120 --> 03:22:50,080 Or there may be no one else 5150 03:22:50,080 --> 03:22:51,720 out there, because they 5151 03:22:51,720 --> 03:22:53,560 destroy themselves with almost 5152 03:22:53,560 --> 03:22:55,000 no exceptions 5153 03:22:55,000 --> 03:22:55,760 before they achieve 5154 03:22:55,760 --> 03:22:58,080 interstellar flight. 5155 03:22:58,080 --> 03:23:01,080 Or maybe, because in a galaxy 5156 03:23:01,080 --> 03:23:04,399 of 400 billion suns, ours is 5157 03:23:04,399 --> 03:23:08,080 the first technical civilization. 5158 03:23:08,080 --> 03:23:10,000 A more likely explanation, I 5159 03:23:10,000 --> 03:23:12,000 think, arises from the simple 5160 03:23:12,000 --> 03:23:16,319 fact that space is vast and 5161 03:23:16,319 --> 03:23:20,319 the stars are far apart. 5162 03:23:20,319 --> 03:23:21,120 Even if there were 5163 03:23:21,120 --> 03:23:23,880 civilizations much older and 5164 03:23:23,880 --> 03:23:26,960 much more advanced than we, expanding 5165 03:23:26,960 --> 03:23:28,880 out from their home worlds, 5166 03:23:28,880 --> 03:23:31,359 reworking new worlds, and then 5167 03:23:31,359 --> 03:23:32,599 continuing onward to other 5168 03:23:32,600 --> 03:23:35,080 stars, they would be unlikely 5169 03:23:35,080 --> 03:23:38,960 to be here yet. 5170 03:23:38,960 --> 03:23:40,480 And because the speed of light is 5171 03:23:40,479 --> 03:23:44,519 finite, the TV and radar news 5172 03:23:44,520 --> 03:23:45,880 that a technical civilization 5173 03:23:45,880 --> 03:23:46,600 has arisen on 5174 03:23:46,600 --> 03:23:48,520 some planet of the Sun has 5175 03:23:48,520 --> 03:23:51,360 not reached them yet. 5176 03:23:51,359 --> 03:23:53,399 Should optimistic estimates 5177 03:23:53,399 --> 03:23:56,040 prevail, and one in every 5178 03:23:56,040 --> 03:23:58,199 million stars shelters a 5179 03:23:58,199 --> 03:24:01,319 nearby technological civilization. 5180 03:24:01,319 --> 03:24:03,279 And if, as well, they're 5181 03:24:03,279 --> 03:24:06,279 randomly strewn through the Milky Way, 5182 03:24:06,279 --> 03:24:08,120 then the nearest one, we 5183 03:24:08,120 --> 03:24:10,080 recall, would be a few 5184 03:24:10,080 --> 03:24:13,279 hundred light-years distant. At the 5185 03:24:13,279 --> 03:24:16,559 closest, maybe a hundred light-years. 5186 03:24:16,560 --> 03:24:19,360 More likely, a thousand light-years. 5187 03:24:19,359 --> 03:24:19,719 And, of 5188 03:24:19,720 --> 03:24:22,240 course, perhaps nowhere, no 5189 03:24:22,239 --> 03:24:25,439 matter how far. Suppose, just just for 5190 03:24:25,439 --> 03:24:26,960 discussion, suppose 5191 03:24:26,960 --> 03:24:28,800 the nearest civilization on a 5192 03:24:28,800 --> 03:24:31,239 planet of another star is, 5193 03:24:31,239 --> 03:24:33,599 say, 200 light years away. 5194 03:24:33,600 --> 03:24:36,240 Then, some 150 years from 5195 03:24:36,239 --> 03:24:38,239 now, they'll begin to receive 5196 03:24:38,239 --> 03:24:41,719 our feeble post-World War II television 5197 03:24:41,720 --> 03:24:44,800 and radar emission. 5198 03:24:44,800 --> 03:24:46,320 What will they make of it? 5199 03:24:47,479 --> 03:24:48,839 With each passing year, the 5200 03:24:48,840 --> 03:24:51,520 signal will get louder, more 5201 03:24:51,520 --> 03:24:56,121 interesting, perhaps more alarming. 5202 03:24:56,120 --> 03:24:59,720 Eventually, they may respond 5203 03:24:59,720 --> 03:25:02,760 by returning a radio message 5204 03:25:02,760 --> 03:25:05,680 or by visiting. 5205 03:25:05,680 --> 03:25:06,920 In either case, the response 5206 03:25:06,920 --> 03:25:08,840 will likely be limited by the 5207 03:25:08,840 --> 03:25:12,880 finite value of the speed of light. 5208 03:25:12,880 --> 03:25:15,640 With these admittedly wildly 5209 03:25:15,640 --> 03:25:18,240 uncertain numbers, the answer 5210 03:25:18,239 --> 03:25:20,319 to our unintentional mid-century 5211 03:25:20,319 --> 03:25:21,439 recall into the depths of 5212 03:25:21,439 --> 03:25:23,559 space, will not arrive until 5213 03:25:23,560 --> 03:25:27,880 around the year 2350. If 5214 03:25:27,880 --> 03:25:28,920 they're farther away, of 5215 03:25:28,920 --> 03:25:31,279 course, it'll take longer. 5216 03:25:31,279 --> 03:25:36,279 And if much farther away, much longer. 5217 03:25:36,279 --> 03:25:37,960 But the beacon signal alone 5218 03:25:37,960 --> 03:25:40,640 would be profoundly significant. 5219 03:25:40,640 --> 03:25:41,800 It would mean 5220 03:25:41,800 --> 03:25:43,239 that someone has learned to 5221 03:25:43,239 --> 03:25:45,679 survive technological adolescence. 5222 03:25:45,680 --> 03:25:47,640 That self-destruction is not 5223 03:25:47,640 --> 03:25:50,680 inevitable, that we also may 5224 03:25:50,680 --> 03:25:57,240 have a future. 5225 03:25:57,239 --> 03:25:58,880 Such knowledge, it seems to 5226 03:25:58,880 --> 03:26:16,239 me, might be worth a great price. 5227 03:26:42,279 --> 03:26:43,479 There are places in and 5228 03:26:43,479 --> 03:26:45,399 around our great cities where 5229 03:26:45,399 --> 03:26:47,439 the natural world has all 5230 03:26:47,439 --> 03:26:49,239 but disappeared. 5231 03:26:49,239 --> 03:26:50,639 You can make out streets and 5232 03:26:50,640 --> 03:26:53,480 sidewalks, autos, parking 5233 03:26:53,479 --> 03:26:57,080 garages, advertising billboards, 5234 03:26:57,080 --> 03:26:57,600 monuments 5235 03:26:57,600 --> 03:26:59,840 of glass and steel, but not 5236 03:26:59,840 --> 03:27:02,199 a tree or a blade of grass 5237 03:27:02,199 --> 03:27:04,080 or any animal, besides, of 5238 03:27:04,080 --> 03:27:06,160 course, the humans. 5239 03:27:06,160 --> 03:27:08,680 There are lots of humans. 5240 03:27:08,680 --> 03:27:09,640 Only when you look straight 5241 03:27:09,640 --> 03:27:10,880 up through the skyscraper 5242 03:27:10,880 --> 03:27:13,560 canyons can you make out a star 5243 03:27:13,560 --> 03:27:16,640 or a patch of blue—reminders 5244 03:27:16,640 --> 03:27:18,161 of what was there long before 5245 03:27:18,160 --> 03:27:20,439 humans came to be. 5246 03:27:20,439 --> 03:27:21,439 But the bright lights of the 5247 03:27:21,439 --> 03:27:22,599 big cities bleach out the 5248 03:27:22,600 --> 03:27:24,960 stars, and even that patch of blue 5249 03:27:24,960 --> 03:27:26,960 is sometimes gone, tinted 5250 03:27:26,960 --> 03:27:30,680 brown by industrial technology. 5251 03:27:30,680 --> 03:27:31,880 It's not hard, going to work 5252 03:27:31,880 --> 03:27:33,560 every day in such a place, 5253 03:27:33,560 --> 03:27:36,161 to be impressed with ourselves, 5254 03:27:36,160 --> 03:27:37,599 how we've transformed the 5255 03:27:37,600 --> 03:27:41,121 Earth for our benefit and convenience. 5256 03:27:41,120 --> 03:27:42,680 But a few hundred miles up 5257 03:27:42,680 --> 03:27:45,800 or down, there are no humans. 5258 03:27:45,800 --> 03:27:47,760 Apart from a thin film of 5259 03:27:47,760 --> 03:27:49,040 life at the very surface of 5260 03:27:49,040 --> 03:27:51,519 the Earth, an occasional intrepid 5261 03:27:51,520 --> 03:27:53,600 spacecraft and some radio 5262 03:27:53,600 --> 03:27:56,000 static, our impact on the 5263 03:27:56,000 --> 03:27:58,600 universe is nil. 5264 03:27:58,600 --> 03:28:05,600 It knows nothing of us. 5265 03:28:05,600 --> 03:28:06,600 What? 5266 03:28:06,600 --> 03:28:09,760 I sometimes ask myself in amazement. 5267 03:28:09,760 --> 03:28:11,800 Our ancestors walked from East 5268 03:28:11,800 --> 03:28:14,520 Africa to Novaya Zemlya and 5269 03:28:14,520 --> 03:28:16,121 Ayers Rock and Patagonia. 5270 03:28:17,359 --> 03:28:18,599 They hunted elephants with 5271 03:28:18,600 --> 03:28:20,440 stone spear points. 5272 03:28:20,439 --> 03:28:22,399 They traversed the polar seas 5273 03:28:22,399 --> 03:28:26,239 in open boats seven thousand years ago. 5274 03:28:26,239 --> 03:28:27,800 They circumnavigated the Earth 5275 03:28:27,800 --> 03:28:30,640 propelled by nothing but wind. 5276 03:28:30,640 --> 03:28:32,400 They walked the Moon a decade 5277 03:28:32,399 --> 03:28:35,599 after entering space, and were 5278 03:28:35,600 --> 03:28:39,800 daunted by a voyage to Mars. 5279 03:28:39,800 --> 03:28:41,720 But then I remind myself of 5280 03:28:41,720 --> 03:28:44,640 the avoidable human suffering on Earth. 5281 03:28:44,640 --> 03:28:46,560 How a few dollars can save 5282 03:28:46,560 --> 03:28:47,880 the life of a child dying 5283 03:28:47,880 --> 03:28:49,920 of dehydration. 5284 03:28:49,920 --> 03:28:51,239 How many children we could 5285 03:28:51,239 --> 03:28:53,279 save for the cost of a trip 5286 03:28:53,279 --> 03:28:56,399 to Mars, and for the moment 5287 03:28:56,399 --> 03:28:58,599 I changed my mind. 5288 03:28:58,600 --> 03:29:01,720 Is it unworthy to stay home, 5289 03:29:01,720 --> 03:29:04,800 or unworthy to go? 5290 03:29:04,800 --> 03:29:08,080 Or have I posed a false dichotomy? 5291 03:29:08,080 --> 03:29:09,199 Isn't it possible to make a 5292 03:29:09,199 --> 03:29:10,359 better life for everyone on 5293 03:29:10,359 --> 03:29:13,239 Earth, and to reach for the planets 5294 03:29:13,239 --> 03:29:16,279 and the stars? 5295 03:29:16,279 --> 03:29:18,319 We had an expansive run in 5296 03:29:18,319 --> 03:29:21,519 the 60s and 70s. 5297 03:29:21,520 --> 03:29:23,440 You might have thought, as I 5298 03:29:23,439 --> 03:29:25,040 did then, that 5299 03:29:25,040 --> 03:29:26,519 our species would be on Mars 5300 03:29:26,520 --> 03:29:28,840 before the century was over. 5301 03:29:28,840 --> 03:29:32,319 But instead, we've pulled inward. 5302 03:29:32,319 --> 03:29:34,960 Robots aside, we've backed off 5303 03:29:34,960 --> 03:29:38,359 from the planets and the stars. 5304 03:29:38,359 --> 03:29:40,719 I keep asking myself, is it 5305 03:29:40,720 --> 03:29:45,120 failure of nerve or a sign of maturity. 5306 03:29:45,120 --> 03:29:46,399 Maybe it's the most we could 5307 03:29:46,399 --> 03:29:48,759 reasonably have expected. 5308 03:29:48,760 --> 03:29:50,440 In a way, it's amazing that 5309 03:29:50,439 --> 03:29:52,479 it was possible at all. 5310 03:29:52,479 --> 03:29:54,160 We sent a dozen humans on 5311 03:29:54,160 --> 03:29:55,720 week-long excursions to the 5312 03:29:55,720 --> 03:29:58,920 moon, and we were given the resources 5313 03:29:58,920 --> 03:30:00,040 to make a preliminary 5314 03:30:00,040 --> 03:30:01,720 reconnaissance of the whole 5315 03:30:01,720 --> 03:30:04,820 solar system—out to Neptune, anyway. 5316 03:30:04,820 --> 03:30:06,880 life, missions that returned a 5317 03:30:06,880 --> 03:30:09,640 wealth of data, but nothing 5318 03:30:09,640 --> 03:30:12,360 of short-term, every-day, 5319 03:30:12,359 --> 03:30:13,880 bread-on-the-table 5320 03:30:13,880 --> 03:30:18,920 practical value, or at least not much. 5321 03:30:18,920 --> 03:30:21,840 They lifted the human spirit, though. 5322 03:30:21,840 --> 03:30:23,040 They enlightened us about our 5323 03:30:23,040 --> 03:30:26,680 place in the universe. 5324 03:30:26,680 --> 03:30:29,760 It is easy to imagine schemes 5325 03:30:29,760 --> 03:30:32,480 of historical causality, in 5326 03:30:32,479 --> 03:30:34,279 which there were no race to 5327 03:30:34,279 --> 03:30:38,559 the Moon, and no planetary program. 5328 03:30:38,560 --> 03:30:39,600 But it is also possible to 5329 03:30:39,600 --> 03:30:40,840 imagine a much more serious 5330 03:30:40,840 --> 03:30:43,319 devotion to exploration, because 5331 03:30:43,319 --> 03:30:46,120 of which we would today have 5332 03:30:46,120 --> 03:30:47,960 robot vehicles probing the 5333 03:30:47,960 --> 03:30:49,760 atmospheres of all the Jovian 5334 03:30:49,760 --> 03:30:52,440 planets and dozens of moons, 5335 03:30:52,439 --> 03:30:54,839 comets and asteroids. 5336 03:30:54,840 --> 03:30:55,960 There were many possible 5337 03:30:55,960 --> 03:30:57,240 historical paths. 5338 03:30:57,240 --> 03:30:59,680 us, our particular causality 5339 03:30:59,680 --> 03:31:02,640 scheme has brought us to a 5340 03:31:02,640 --> 03:31:06,200 modest and rudimentary, although in 5341 03:31:06,199 --> 03:31:08,160 many respects heroic, series 5342 03:31:08,160 --> 03:31:10,680 of explorations. 5343 03:31:10,680 --> 03:31:12,880 But it is far inferior to 5344 03:31:12,880 --> 03:31:15,400 what might have been, and 5345 03:31:15,399 --> 03:31:18,120 what may one day be. 5346 03:31:18,120 --> 03:31:20,040 In more than one respect, 5347 03:31:20,040 --> 03:31:22,120 exploring the solar system and 5348 03:31:22,120 --> 03:31:24,160 homesteading other worlds constitutes 5349 03:31:24,160 --> 03:31:25,880 constitutes the beginning, much 5350 03:31:25,880 --> 03:31:45,840 more than the end, of history. 5351 03:31:55,359 --> 03:31:57,359 And so, after a voyage of 5352 03:31:57,359 --> 03:31:59,639 100 million kilometers, on 5353 03:31:59,640 --> 03:32:04,000 July 20th, 1976, Viking 1 landed right 5354 03:32:04,000 --> 03:32:09,479 on target in the Cricey Plain. 5355 03:32:09,479 --> 03:32:11,199 It was less than 80 years 5356 03:32:11,199 --> 03:32:12,960 since Robert Goddard had his 5357 03:32:12,960 --> 03:32:15,000 epiphanal vision in a cherry 5358 03:32:15,000 --> 03:32:35,960 tree in Massachusetts. 5359 03:32:35,960 --> 03:32:37,359 The Viking Lander is a 5360 03:32:37,359 --> 03:32:39,519 superbly instrumented and 5361 03:32:39,520 --> 03:32:41,600 designed machine. 5362 03:32:41,600 --> 03:32:43,600 It extends human capabilities 5363 03:32:43,600 --> 03:32:45,840 to other and alien landscapes. 5364 03:32:46,359 --> 03:32:47,880 By some standards, it's about 5365 03:32:47,880 --> 03:32:50,800 as smart as a grasshopper. 5366 03:32:50,800 --> 03:32:52,480 By others, only as intelligent 5367 03:32:52,479 --> 03:32:54,080 as a bacterium. 5368 03:32:54,080 --> 03:32:55,559 There's nothing demeaning in 5369 03:32:55,560 --> 03:32:56,440 these comparisons. 5370 03:32:56,439 --> 03:32:58,000 It took nature hundreds of 5371 03:32:58,000 --> 03:33:00,399 millions of years to evolve a 5372 03:33:00,399 --> 03:33:01,239 bacterium, 5373 03:33:01,239 --> 03:33:02,399 and billions of years to make 5374 03:33:02,399 --> 03:33:03,799 a grasshopper. 5375 03:33:03,800 --> 03:33:05,160 With only a little experience 5376 03:33:05,160 --> 03:33:06,439 in this sort of business, 5377 03:33:06,439 --> 03:33:09,120 we're getting pretty good at it. 5378 03:33:09,120 --> 03:33:10,319 One of the things that a 5379 03:33:10,319 --> 03:33:12,319 grasshopper can do, but Viking 5380 03:33:12,319 --> 03:33:14,519 can't, is move. 5381 03:33:14,520 --> 03:33:17,121 We landed in the dull places on Mars. 5382 03:33:17,120 --> 03:33:18,880 For all the solid scientific 5383 03:33:18,880 --> 03:33:20,760 findings and tantalizing hints 5384 03:33:20,760 --> 03:33:22,320 which Viking provided, 5385 03:33:22,319 --> 03:33:23,359 we know that there are an 5386 03:33:23,359 --> 03:33:24,719 enormous number of places on 5387 03:33:24,720 --> 03:33:27,360 the planet far more interesting. 5388 03:33:27,359 --> 03:33:29,719 What we need is a roving 5389 03:33:29,720 --> 03:33:30,880 vehicle with advanced 5390 03:33:30,880 --> 03:33:32,199 experiments in biology and 5391 03:33:32,199 --> 03:33:33,559 organic chemistry, 5392 03:33:33,560 --> 03:33:35,440 able to land in the safe but 5393 03:33:35,439 --> 03:33:37,439 dull places and wander to the 5394 03:33:37,439 --> 03:33:38,960 interesting places. 5395 03:33:38,960 --> 03:33:40,640 A Mars rover hasn't got time 5396 03:33:40,640 --> 03:33:41,880 to ask whether it should 5397 03:33:41,880 --> 03:33:43,840 attempt the steep slope. 5398 03:33:43,840 --> 03:33:45,199 Radio waves traveling at the 5399 03:33:45,199 --> 03:33:46,840 speed of light take about 20 5400 03:33:46,840 --> 03:33:48,720 minutes for the round trip to Earth. 5401 03:33:48,720 --> 03:33:49,560 By the time it got an 5402 03:33:49,560 --> 03:33:51,640 answer, it might be a heap 5403 03:33:51,640 --> 03:33:53,240 of twisted metal at the 5404 03:33:53,239 --> 03:33:54,800 bottom of a canyon. 5405 03:33:54,800 --> 03:33:59,120 A rover has to think for itself. 5406 03:33:59,120 --> 03:34:01,160 Imagine a rover with laser 5407 03:34:01,160 --> 03:34:02,760 eyes like this one, 5408 03:34:02,760 --> 03:34:04,440 but packed with sophisticated 5409 03:34:04,439 --> 03:34:06,559 biological and chemical instruments, 5410 03:34:06,560 --> 03:34:08,440 sampler arms, microscopes and 5411 03:34:08,439 --> 03:34:10,040 television cameras, 5412 03:34:10,040 --> 03:34:14,080 wandering over the Martian landscape. 5413 03:34:14,080 --> 03:34:15,319 It could drive to its own 5414 03:34:15,319 --> 03:34:17,279 horizon every day, 5415 03:34:17,279 --> 03:34:18,920 a distant feature that barely 5416 03:34:18,920 --> 03:34:20,760 resolves at sunrise. 5417 03:34:20,760 --> 03:34:22,800 It can be sniffing and 5418 03:34:22,800 --> 03:34:29,239 tasting by nightfall. 5419 03:34:29,239 --> 03:34:31,120 Billions of people could watch 5420 03:34:31,120 --> 03:34:33,080 the unfolding adventure on 5421 03:34:33,080 --> 03:34:34,439 their television sets 5422 03:34:34,439 --> 03:34:36,000 as the rover explores the 5423 03:34:36,000 --> 03:34:37,560 ancient river bottoms 5424 03:34:37,560 --> 03:34:39,520 or cautiously approaches the 5425 03:34:39,520 --> 03:34:43,840 enigmatic pyramids of Elysium. 5426 03:34:43,840 --> 03:34:45,199 Most of the human species 5427 03:34:45,199 --> 03:34:47,920 would witness the exploration 5428 03:34:47,920 --> 03:34:50,720 of another world. 5429 03:34:50,720 --> 03:34:52,800 A new age of discovery would 5430 03:34:52,800 --> 03:35:00,199 have begun. 5431 03:35:00,199 --> 03:35:01,880 Science is a collaborative 5432 03:35:01,880 --> 03:35:04,520 enterprise spanning the generations. 5433 03:35:04,520 --> 03:35:06,161 When it permits us to see 5434 03:35:06,160 --> 03:35:08,319 the far side of some new 5435 03:35:08,319 --> 03:35:10,840 horizon, we remember those who prepared 5436 03:35:10,840 --> 03:35:15,640 the way, seeing for them also. 364454

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