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These are the user uploaded subtitles that are being translated: 1 00:00:04,099 --> 00:00:07,767 Orbiting the magnificent ringed planet, Saturn, 2 00:00:07,867 --> 00:00:11,000 are a series of extraordinary moons. 3 00:00:13,867 --> 00:00:15,266 The closer that we look, 4 00:00:15,367 --> 00:00:19,100 the more that we see its moons are like worlds of their own... 5 00:00:19,166 --> 00:00:20,800 So dynamic, so Earth-like. 6 00:00:21,867 --> 00:00:25,000 Almost a billion miles from the Sun, 7 00:00:25,065 --> 00:00:29,667 these icy worlds could be home for Life 2.0. 8 00:00:31,567 --> 00:00:34,643 The moons of Saturn offer possibly the best 9 00:00:34,667 --> 00:00:37,500 chance of finding extraterrestrial life 10 00:00:37,567 --> 00:00:38,799 in our solar system. 11 00:00:42,799 --> 00:00:45,899 With each new mission, we get closer 12 00:00:46,000 --> 00:00:49,466 to unraveling the mysteries of Saturn's moons. 13 00:01:07,299 --> 00:01:09,299 October 2019. 14 00:01:09,367 --> 00:01:13,099 Astronomers discover 20 new moons 15 00:01:13,165 --> 00:01:16,042 orbiting the gas giant, Saturn. 16 00:01:16,066 --> 00:01:21,000 These tiny, three-mile-wide objects 17 00:01:21,066 --> 00:01:24,867 bring the ringed planet's moon count to over 80, 18 00:01:26,966 --> 00:01:29,975 the most of any planet in our solar system. 19 00:01:30,000 --> 00:01:31,680 The most of any planet in our solar system. 20 00:01:32,766 --> 00:01:34,643 You hate to play favorites, but I'm gonna say it... 21 00:01:34,667 --> 00:01:38,500 Saturn is my favorite planetary system. 22 00:01:38,567 --> 00:01:41,942 It is unbelievably beautiful, with this incredible system of 23 00:01:41,966 --> 00:01:43,442 rings and moons, 24 00:01:43,466 --> 00:01:48,000 and there's a lot of mystery kind of all bound up in there. 25 00:01:50,366 --> 00:01:52,000 The Voyager spacecraft gave us our 26 00:01:52,066 --> 00:01:55,200 first close look at Saturn and its rings. 27 00:01:56,567 --> 00:01:59,975 Two decades later, Cassini got us even closer 28 00:02:00,000 --> 00:02:01,543 Two decades later, Cassini got us even closer 29 00:02:01,566 --> 00:02:03,367 to many of Saturn's moons. 30 00:02:05,867 --> 00:02:09,199 There's Prometheus, Pandora, and Atlas. 31 00:02:10,366 --> 00:02:14,943 Its largest moon, Titan, is a moon that's shrouded 32 00:02:14,967 --> 00:02:17,165 in mystery. 33 00:02:17,265 --> 00:02:21,443 There's Mimas, that's fairly small, 34 00:02:21,466 --> 00:02:23,699 and then Tethys and Dione are a bit larger. 35 00:02:25,165 --> 00:02:27,599 There are a pair of moons... Janus and Epimetheus... 36 00:02:27,667 --> 00:02:29,466 That were perhaps one moon in the past. 37 00:02:31,165 --> 00:02:33,300 Iapetus, half of it's bright white. 38 00:02:33,366 --> 00:02:34,687 The other half of it is sort of as 39 00:02:34,766 --> 00:02:37,099 dark as coal, sort of yin and yang. 40 00:02:39,366 --> 00:02:42,466 Each of the moons of Saturn 41 00:02:42,567 --> 00:02:45,366 had remarkable stories to tell. 42 00:02:46,466 --> 00:02:49,500 In 2005, Cassini discovered that 43 00:02:49,567 --> 00:02:53,742 one moon's story was particularly exciting. 44 00:02:53,766 --> 00:02:55,742 Yeah, Enceladus. 45 00:02:55,766 --> 00:02:58,742 Enceladus is one of Saturn's wee little moons. 46 00:02:58,766 --> 00:02:59,975 It's about 300 miles across... For scale, 47 00:03:00,000 --> 00:03:01,342 It's about 300 miles across... For scale, 48 00:03:01,366 --> 00:03:03,467 it's roughly the size of Colorado. 49 00:03:06,199 --> 00:03:09,342 The spacecraft's cameras spot plumes of 50 00:03:09,366 --> 00:03:12,567 water vapor shooting out from Enceladus 51 00:03:13,667 --> 00:03:15,400 at 800 miles an hour. 52 00:03:18,466 --> 00:03:20,241 Three times as powerful than 53 00:03:20,265 --> 00:03:22,900 all the hot springs in Yellowstone. 54 00:03:25,766 --> 00:03:29,042 The discovery of geysers gushing out of tiny, 55 00:03:29,066 --> 00:03:29,977 little Enceladus that should have been cold and dead, 56 00:03:30,001 --> 00:03:31,543 little Enceladus that should have been cold and dead, 57 00:03:31,567 --> 00:03:34,500 completely changed our view of what that moon exactly was. 58 00:03:36,066 --> 00:03:38,543 It's alive. That moon is alive. 59 00:03:38,567 --> 00:03:41,241 I'd like to be standing there on the surface of Enceladus to 60 00:03:41,265 --> 00:03:43,300 see with the... this water vapor 61 00:03:43,366 --> 00:03:46,000 and ice crystals booming out of the surface 62 00:03:46,066 --> 00:03:47,667 at supersonic speeds. 63 00:03:55,866 --> 00:03:59,500 Cassini's sensors probe deep beneath 64 00:03:59,567 --> 00:03:59,977 the frozen surface of Enceladus, 65 00:04:00,001 --> 00:04:01,643 the frozen surface of Enceladus, 66 00:04:01,667 --> 00:04:06,000 detecting hints of a rocky core 67 00:04:06,099 --> 00:04:09,099 and something else even more remarkable. 68 00:04:11,165 --> 00:04:13,667 Underneath that thick layer of ice, 69 00:04:13,766 --> 00:04:16,242 there is liquid water ocean. 70 00:04:16,266 --> 00:04:20,100 The measurements suggest his is a huge part of 71 00:04:20,165 --> 00:04:21,867 Enceladus's interior volume, 72 00:04:21,966 --> 00:04:25,300 about six miles deep, because it was making Enceladus 73 00:04:25,367 --> 00:04:26,766 wobble in its orbit. 74 00:04:26,867 --> 00:04:29,399 Imagine putting liquid inside a ball and rolling it. 75 00:04:29,466 --> 00:04:29,975 You see the natural wobble of 76 00:04:30,000 --> 00:04:30,800 You see the natural wobble of 77 00:04:30,867 --> 00:04:32,800 the ball as the liquid sloshes around. 78 00:04:34,266 --> 00:04:38,667 Giant liquid oceans on an alien world, 79 00:04:38,766 --> 00:04:41,567 opening up exciting new possibilities. 80 00:04:42,667 --> 00:04:46,399 Where you find water, you could possibly find life. 81 00:04:49,266 --> 00:04:52,199 If you had asked me 20 years ago where there might be life 82 00:04:52,266 --> 00:04:54,165 in the solar system besides Earth, 83 00:04:54,266 --> 00:04:56,766 I think Saturn's moons would have been the last place 84 00:04:56,867 --> 00:04:58,466 I would have picked. 85 00:04:58,567 --> 00:04:59,975 But against all odds, it's looking like this tiny icy 86 00:05:00,000 --> 00:05:02,242 But against all odds, it's looking like this tiny icy 87 00:05:02,266 --> 00:05:03,800 moon orbiting Saturn 88 00:05:03,867 --> 00:05:06,800 nearly a billion miles from the Sun may be one of 89 00:05:06,867 --> 00:05:09,266 the best places to look for life. 90 00:05:10,699 --> 00:05:14,065 July 2021. 91 00:05:15,100 --> 00:05:18,466 A new study reexamines Cassini's plume data 92 00:05:20,100 --> 00:05:22,766 and finds huge quantities of methane. 93 00:05:25,000 --> 00:05:26,242 This large amount can't be 94 00:05:26,266 --> 00:05:29,466 explained by just geochemical processes. 95 00:05:32,000 --> 00:05:35,242 The methane might be from primordial organic matter 96 00:05:35,266 --> 00:05:38,266 breaking down in Enceladus's oceans, 97 00:05:38,367 --> 00:05:46,367 or even processes we've never seen before. 98 00:05:47,966 --> 00:05:49,066 But it could be that 99 00:05:49,100 --> 00:05:53,100 living microorganisms helped generate the methane, 100 00:05:53,165 --> 00:05:55,600 just like they do on Earth. 101 00:05:56,966 --> 00:05:59,975 Enceladus might actually look a lot like early Earth in its 102 00:06:00,000 --> 00:06:00,666 Enceladus might actually look a lot like early Earth in its 103 00:06:00,766 --> 00:06:02,843 deepest oceans, when life was first arising, 104 00:06:02,867 --> 00:06:05,242 because we know that there are some chemical pathways that are 105 00:06:05,266 --> 00:06:08,000 likely occurring on Enceladus that happened on Earth. 106 00:06:12,266 --> 00:06:14,199 These chemical pathways start with 107 00:06:14,266 --> 00:06:16,843 hot, hydrothermal vents on Earth's 108 00:06:16,867 --> 00:06:21,600 cold sea floor, releasing important life-giving chemicals 109 00:06:21,667 --> 00:06:24,300 into the oceans. 110 00:06:24,367 --> 00:06:26,843 Having hydrothermal vents are a real 111 00:06:26,867 --> 00:06:29,165 boon to the evolution of life. 112 00:06:29,266 --> 00:06:29,976 These are cracks in the Earth's crust, where 113 00:06:30,000 --> 00:06:32,141 These are cracks in the Earth's crust, where 114 00:06:32,165 --> 00:06:36,899 hot material can then spew out into the ocean. 115 00:06:37,000 --> 00:06:38,442 And that's the energy 116 00:06:38,466 --> 00:06:39,742 that life needs to be able to form, 117 00:06:39,766 --> 00:06:42,100 and then water so everything is present, and things 118 00:06:42,165 --> 00:06:44,867 are able to just grab all these resources and energy 119 00:06:44,966 --> 00:06:47,600 and just start to evolve. 120 00:06:47,667 --> 00:06:51,667 On Earth, hydrothermal vents produce methane, 121 00:06:51,766 --> 00:06:53,843 but only in small amounts. 122 00:06:53,867 --> 00:06:56,500 Microbial life 123 00:06:56,567 --> 00:06:59,600 living around the vents makes the rest. 124 00:07:03,600 --> 00:07:07,399 Maybe microorganisms do the same 125 00:07:07,466 --> 00:07:14,442 at the bottom of Enceladus's deep oceans. 126 00:07:14,466 --> 00:07:17,667 Hydrothermal vents on Enceladus could offer 127 00:07:17,766 --> 00:07:21,141 the perfect location for chemistry 128 00:07:21,165 --> 00:07:24,165 becoming biochemistry becoming life. 129 00:07:26,466 --> 00:07:29,399 Hydrothermal vents normally require 130 00:07:29,466 --> 00:07:29,976 heat from a hot core. 131 00:07:30,000 --> 00:07:31,466 Heat from a hot core. 132 00:07:36,367 --> 00:07:40,899 So what's going on inside Enceladus? 133 00:07:41,000 --> 00:07:46,042 This is an icy moon out there in the cold outer solar system. 134 00:07:46,066 --> 00:07:48,800 Where is all this heat coming from? 135 00:07:48,867 --> 00:07:52,199 Cassini spotted Enceladus's plumes 136 00:07:52,266 --> 00:07:54,266 shooting out from parallel cracks 137 00:07:54,367 --> 00:07:57,466 in the surface, called tiger stripes. 138 00:08:02,500 --> 00:08:06,000 The cracks are a clue to the origin of the geysers 139 00:08:06,100 --> 00:08:08,065 and the energy that powers them. 140 00:08:11,000 --> 00:08:12,899 We look to the orbit of Enceladus itself. 141 00:08:13,000 --> 00:08:14,800 It's not in a perfectly circular orbit 142 00:08:14,867 --> 00:08:16,100 around the planet. 143 00:08:16,165 --> 00:08:18,567 It's on a slightly elliptical orbit, and that means that 144 00:08:18,667 --> 00:08:22,442 the tidal forces acting on the moon change over time. 145 00:08:22,466 --> 00:08:25,567 It's a little bit like the forces on a rubber ball. 146 00:08:25,667 --> 00:08:29,442 When the moon is closer to the planet, it's stretched out, 147 00:08:29,466 --> 00:08:29,976 and when the moon is farther from the planet, 148 00:08:30,000 --> 00:08:31,242 and when the moon is farther from the planet, 149 00:08:31,266 --> 00:08:34,600 it's relaxed back a little bit, so you're gonna squeeze 150 00:08:34,667 --> 00:08:36,842 and deform and squish the body of 151 00:08:36,866 --> 00:08:39,767 that moon over time, which is gonna heat its interior. 152 00:08:43,767 --> 00:08:46,543 The warm, rocky core heats up the ocean, 153 00:08:46,567 --> 00:08:49,899 which both powers the geysers as they burst 154 00:08:50,000 --> 00:08:51,066 through the surface 155 00:08:52,767 --> 00:08:56,899 and creates conditions that could support life. 156 00:09:00,399 --> 00:09:02,667 We see the energy source kicking the water 157 00:09:02,767 --> 00:09:04,700 out of the Enceladus subsurface. 158 00:09:04,767 --> 00:09:07,042 You combine that energy source 159 00:09:07,066 --> 00:09:09,342 and liquid water, that harkens to putting 160 00:09:09,366 --> 00:09:11,466 us on the same path that early life 161 00:09:11,567 --> 00:09:13,200 may have taken here on the Earth. 162 00:09:13,265 --> 00:09:14,567 And if that's the case, 163 00:09:14,667 --> 00:09:17,042 there could be little beasties swimming underneath the surface 164 00:09:17,066 --> 00:09:18,567 of one of Saturn's moons. 165 00:09:20,567 --> 00:09:22,842 Saturn's squeezing of Enceladus may 166 00:09:22,866 --> 00:09:25,567 have transformed it into a living world, 167 00:09:29,200 --> 00:09:29,976 but other moons weren't as lucky. 168 00:09:30,000 --> 00:09:31,299 But other moons weren't as lucky. 169 00:09:33,066 --> 00:09:36,799 They've been torn apart in vicious fights 170 00:09:36,866 --> 00:09:38,100 to the death. 171 00:09:54,667 --> 00:09:58,700 There are a huge variety of moons orbiting Saturn, 172 00:09:59,966 --> 00:10:06,100 from Titan, a moon larger than the planet Mercury, 173 00:10:06,166 --> 00:10:09,366 to objects about the size of a sports stadium. 174 00:10:10,667 --> 00:10:12,567 There must be something dramatic that happened 175 00:10:12,667 --> 00:10:13,899 to create a system 176 00:10:14,000 --> 00:10:15,743 that's so complicated and changing 177 00:10:15,767 --> 00:10:16,894 before our very eyes. 178 00:10:16,918 --> 00:10:18,299 Before our very eyes. 179 00:10:18,366 --> 00:10:22,042 To understand such a marked difference in size, 180 00:10:22,066 --> 00:10:26,000 scientists look for clues in the moon's orbits around 181 00:10:26,066 --> 00:10:27,667 Saturn itself. 182 00:10:29,366 --> 00:10:32,799 Most of the moons of that system orbit in the same direction. 183 00:10:32,866 --> 00:10:34,942 That's obviously not a coincidence. 184 00:10:34,966 --> 00:10:37,442 That's motion left over from the formation 185 00:10:37,466 --> 00:10:38,767 of our solar system. 186 00:10:40,000 --> 00:10:42,466 This suggests the moons formed around 187 00:10:42,567 --> 00:10:44,500 the same time as Saturn did. 188 00:10:45,500 --> 00:10:46,894 4.6 billion years ago, 189 00:10:46,918 --> 00:10:47,942 4.6 billion years ago, 190 00:10:47,966 --> 00:10:51,165 the ringless gas giant grows from gas, 191 00:10:51,265 --> 00:10:54,743 rock, and ice in the protoplanetary disk, 192 00:10:54,767 --> 00:10:56,866 along with a family of moons. 193 00:10:59,667 --> 00:11:03,366 This origin story works for most of Saturn's moons, 194 00:11:06,166 --> 00:11:09,442 but not for the recently discovered objects orbiting 195 00:11:09,466 --> 00:11:13,000 in the opposite direction of the planet's rotation. 196 00:11:14,265 --> 00:11:16,894 If there's a moon orbiting in the other direction, 197 00:11:16,918 --> 00:11:17,644 If there's a moon orbiting in the other direction, 198 00:11:17,668 --> 00:11:19,567 it couldn't have formed with the planet. 199 00:11:20,667 --> 00:11:22,767 It must have come from somewhere else. 200 00:11:24,200 --> 00:11:26,265 Saturn captured these moons. 201 00:11:27,799 --> 00:11:29,299 But from where? 202 00:11:33,366 --> 00:11:35,700 We think there was a huge upheaval in the solar system 203 00:11:35,767 --> 00:11:37,100 over four billion years ago, 204 00:11:37,165 --> 00:11:38,942 where the giant planets 205 00:11:38,966 --> 00:11:42,165 went from a close and compact configuration, started 206 00:11:42,265 --> 00:11:43,842 having interactions with each other, 207 00:11:43,866 --> 00:11:46,442 moved each other around to end up into the orbits 208 00:11:46,466 --> 00:11:46,894 that they find today. 209 00:11:46,918 --> 00:11:47,543 That they find today. 210 00:11:47,567 --> 00:11:50,042 During that process, a lot of smaller bodies, 211 00:11:50,066 --> 00:11:51,567 like asteroids from the distant part 212 00:11:51,667 --> 00:11:53,000 of the solar system got scattered 213 00:11:53,066 --> 00:11:54,966 every which direction. 214 00:11:56,600 --> 00:11:59,100 During this ancient upheaval, 215 00:11:59,165 --> 00:12:01,667 Saturn grabs some of the scattered objects. 216 00:12:04,567 --> 00:12:08,000 Many bodies now crowd the region around the planet, 217 00:12:09,567 --> 00:12:12,000 and that means collisions. 218 00:12:15,667 --> 00:12:16,894 Some are destructive. 219 00:12:16,918 --> 00:12:17,600 Some are destructive. 220 00:12:17,667 --> 00:12:19,899 Others form new moons. 221 00:12:21,366 --> 00:12:22,767 In the cosmic pinball, 222 00:12:22,866 --> 00:12:25,166 some moons are thrown out of the system, 223 00:12:27,166 --> 00:12:29,567 and others, into Saturn. 224 00:12:29,667 --> 00:12:32,767 Only one large moon survives the carnage. 225 00:12:34,466 --> 00:12:35,907 And all of a sudden, most of the mass 226 00:12:36,000 --> 00:12:38,165 of all the satellites is in that single moon, Titan. 227 00:12:41,165 --> 00:12:44,399 Titan may have formed from the material in 228 00:12:44,466 --> 00:12:46,894 the protoplanetary disk at the same time as Saturn, 229 00:12:46,918 --> 00:12:48,142 the protoplanetary disk at the same time as Saturn, 230 00:12:48,165 --> 00:12:52,442 but then gorged on the debris created in the later 231 00:12:52,466 --> 00:12:57,500 lunar collisions. 232 00:12:57,567 --> 00:13:03,200 It amassed 96 percent of the material orbiting Saturn 233 00:13:03,265 --> 00:13:06,799 and grew so large that it developed a dense atmosphere. 234 00:13:11,166 --> 00:13:13,265 When Voyager photographed Titan, 235 00:13:13,366 --> 00:13:15,942 it clearly showed that Titan had a thick atmosphere, 236 00:13:15,966 --> 00:13:16,895 which was so incredibly exciting, 237 00:13:16,919 --> 00:13:18,399 which was so incredibly exciting, 238 00:13:18,466 --> 00:13:20,299 but it was so dense and impenetrable, 239 00:13:20,366 --> 00:13:22,899 that was all we could see. 240 00:13:24,466 --> 00:13:26,567 Two decades after Voyager, 241 00:13:26,667 --> 00:13:29,399 the Huygens Probe launched from Cassini 242 00:13:30,866 --> 00:13:34,799 and plunged through the murky depths of Titan's atmosphere. 243 00:13:40,966 --> 00:13:42,667 Our first images of what 244 00:13:42,767 --> 00:13:45,165 the Titanic landscape was like 245 00:13:45,265 --> 00:13:46,894 were utterly and truly mind-blowing. 246 00:13:46,918 --> 00:13:50,299 Were utterly and truly mind-blowing. 247 00:13:50,366 --> 00:13:51,700 It showed there were mountains 248 00:13:51,767 --> 00:13:52,842 and there was sort of erosion 249 00:13:52,866 --> 00:13:54,743 on those mountains that looked like liquid 250 00:13:54,767 --> 00:13:57,899 had fallen down the mountains and brought material with it. 251 00:13:59,265 --> 00:14:01,342 That liquid must have come from somewhere. 252 00:14:01,366 --> 00:14:03,200 And where else than rain, 253 00:14:03,265 --> 00:14:04,466 the weather on Titan? 254 00:14:06,100 --> 00:14:08,842 We've only found two places in the solar system 255 00:14:08,866 --> 00:14:12,000 with rivers and rain... 256 00:14:12,100 --> 00:14:15,866 Earth and Titan. 257 00:14:15,966 --> 00:14:16,895 Out of this thick gloom, 258 00:14:16,919 --> 00:14:18,200 Out of this thick gloom, 259 00:14:18,265 --> 00:14:22,366 this is the most similar place to Earth we've ever seen. 260 00:14:22,466 --> 00:14:25,466 Similar, but not identical. 261 00:14:27,265 --> 00:14:32,200 That rain filling lakes and rivers on Titan isn't water. 262 00:14:33,265 --> 00:14:34,600 It's liquid methane. 263 00:14:36,066 --> 00:14:39,466 It's like if every oil well, if every gas station on 264 00:14:39,567 --> 00:14:41,543 Earth started leaking all over the place, 265 00:14:41,567 --> 00:14:44,200 that is what we see on this world. 266 00:14:47,066 --> 00:14:48,866 The methane is a liquid on Titan 267 00:14:48,966 --> 00:14:53,567 because the surface temperature is 290 degrees below zero, 268 00:14:54,866 --> 00:14:57,265 which is a big problem for life 269 00:14:57,366 --> 00:14:59,265 as we understand it. 270 00:15:00,767 --> 00:15:03,667 We don't know of any organism that can really survive past 271 00:15:03,767 --> 00:15:06,166 negative 4 degrees Fahrenheit, and that's just because 272 00:15:06,265 --> 00:15:08,799 cells will tend to freeze there. 273 00:15:08,866 --> 00:15:10,543 The cells that we have, 274 00:15:10,567 --> 00:15:13,466 what they're made up from, these proteins and fatty 275 00:15:13,567 --> 00:15:16,894 material, stop working, and everything would die. 276 00:15:16,918 --> 00:15:17,799 Material, stop working, and everything would die. 277 00:15:17,866 --> 00:15:22,500 That's what happens to Earth's water-based cells. 278 00:15:25,200 --> 00:15:30,299 But could methane-based life survive in extreme cold? 279 00:15:33,066 --> 00:15:36,643 The ALMA telescope spotted a clue in Titan's nitrogen- 280 00:15:36,667 --> 00:15:39,500 and-methane-rich atmosphere. 281 00:15:39,567 --> 00:15:43,366 With sunlight hitting the atmosphere of Titan, 282 00:15:43,466 --> 00:15:46,643 things like methane and nitrogen can get broken apart 283 00:15:46,667 --> 00:15:46,895 and reassembled, like playing with LEGO blocks, 284 00:15:46,919 --> 00:15:50,866 and reassembled, like playing with LEGO blocks, 285 00:15:50,966 --> 00:15:54,165 and then these molecules recombine to 286 00:15:54,265 --> 00:15:57,165 make new ones, like vinyl cyanide. 287 00:15:59,200 --> 00:16:01,166 Artist depiction. 288 00:16:01,265 --> 00:16:06,767 Used on Earth to make plastics, vinyl cyanide can 289 00:16:06,866 --> 00:16:09,100 build long chains of molecules, 290 00:16:09,166 --> 00:16:12,700 the type you need to build cell membranes. 291 00:16:18,767 --> 00:16:21,466 But unlike Earth's water-based cells, 292 00:16:21,567 --> 00:16:24,366 the extreme cold wouldn't destroy them. 293 00:16:26,899 --> 00:16:29,100 It could survive at those low temperatures. 294 00:16:29,166 --> 00:16:33,165 So on Titan, it could be that this vinyl cyanide is able 295 00:16:33,265 --> 00:16:34,700 to form the membranes 296 00:16:34,767 --> 00:16:36,500 that are required for cells to develop, 297 00:16:36,567 --> 00:16:39,200 which are required for life to happen. 298 00:16:43,000 --> 00:16:45,165 And good news... 299 00:16:45,265 --> 00:16:46,894 There's a lot of this stuff on Titan right now. 300 00:16:46,918 --> 00:16:48,759 There's a lot of this stuff on Titan right now. 301 00:16:50,866 --> 00:16:55,299 There's as much as 10 billion tons of this vinyl cyanide 302 00:16:55,366 --> 00:16:56,767 in just one of the lakes. 303 00:16:56,866 --> 00:16:58,842 If you want to start making creatures out of it... 304 00:16:58,866 --> 00:17:00,743 Say, I don't know, a giant squid... 305 00:17:00,767 --> 00:17:02,265 Do you like giant squids? 306 00:17:02,366 --> 00:17:05,742 I hope so, because you could make billions 307 00:17:05,767 --> 00:17:11,241 of giant squids out of this vinyl cyanide. 308 00:17:11,266 --> 00:17:14,142 Saturn's geyser moon, Enceladus, 309 00:17:14,165 --> 00:17:16,666 could have life as we know it. 310 00:17:16,767 --> 00:17:16,895 Titan might have something truly alien. 311 00:17:16,920 --> 00:17:21,700 Titan might have something truly alien. 312 00:17:21,767 --> 00:17:25,200 It is an unrelentingly brutal, 313 00:17:25,266 --> 00:17:28,200 cold place compared to Earth. 314 00:17:28,266 --> 00:17:31,666 But for Titanic life, it might just be ideal. 315 00:17:33,266 --> 00:17:34,767 As we search for life beyond Earth, 316 00:17:34,866 --> 00:17:38,266 it still comes with a bias of life as we know it. 317 00:17:38,366 --> 00:17:40,400 And so it's great, as we continue 318 00:17:40,467 --> 00:17:43,299 to explore and continue to evolve our definitions, 319 00:17:43,366 --> 00:17:46,894 we can expand our view of how to search for life. 320 00:17:46,919 --> 00:17:48,343 We can expand our view of how to search for life. 321 00:17:48,366 --> 00:17:52,400 Maybe the Saturn system has two living worlds. 322 00:17:54,799 --> 00:17:58,843 But for life to thrive on Titan's surface, 323 00:17:58,866 --> 00:18:02,742 it must survive a storm of deadly particles 324 00:18:02,767 --> 00:18:04,843 racing out of the Sun 325 00:18:04,866 --> 00:18:07,000 at over a million miles an hour. 326 00:18:22,599 --> 00:18:25,567 The sun provides light and warmth... 327 00:18:29,366 --> 00:18:34,000 and something else, something very dangerous... 328 00:18:34,099 --> 00:18:35,099 The solar wind. 329 00:18:38,567 --> 00:18:41,742 These lethal solar particles can strip away 330 00:18:41,767 --> 00:18:44,836 atmosphere from planets and moons. 331 00:18:44,859 --> 00:18:46,180 Atmosphere from planets and moons. 332 00:18:48,299 --> 00:18:50,299 Without an atmosphere, 333 00:18:50,366 --> 00:18:52,742 Earth would be a barren desert, right? 334 00:18:52,767 --> 00:18:55,366 There wouldn't be any water, it would just all boil away. 335 00:18:55,467 --> 00:18:57,567 There wouldn't be any life, 336 00:18:58,700 --> 00:19:02,666 Luckily, Earth has a built-in defense system. 337 00:19:04,099 --> 00:19:05,400 In the center of our Earth, 338 00:19:05,467 --> 00:19:09,843 we have a solid iron core, and surrounding that is liquid iron 339 00:19:09,866 --> 00:19:14,000 that is constantly moving and swirling and convecting, 340 00:19:14,099 --> 00:19:14,836 and these complex motions 341 00:19:14,859 --> 00:19:15,567 and these complex motions 342 00:19:15,666 --> 00:19:19,567 power up a global-scale magnetic field 343 00:19:23,266 --> 00:19:25,165 And this acts like a force field 344 00:19:25,266 --> 00:19:27,799 against the solar wind, pushes it away, 345 00:19:27,866 --> 00:19:29,666 pushes it around us so it doesn't hit us. 346 00:19:31,266 --> 00:19:34,400 We think that Saturn's moon, Titan, 347 00:19:34,467 --> 00:19:37,066 has no molten iron core 348 00:19:39,567 --> 00:19:43,799 and therefore no protective magnetic field. 349 00:19:43,866 --> 00:19:44,836 So it's at the mercy of the solar wind. 350 00:19:44,861 --> 00:19:46,500 So it's at the mercy of the solar wind. 351 00:19:47,666 --> 00:19:50,200 It kind of begs the question, why does Titan 352 00:19:50,266 --> 00:19:52,767 have such a thick, dense atmosphere? 353 00:19:52,866 --> 00:19:57,366 Titan retaining an atmosphere without 354 00:19:57,467 --> 00:20:00,266 a protective shield makes no sense. 355 00:20:03,000 --> 00:20:05,099 Titan doesn't have a magnetic field, 356 00:20:05,165 --> 00:20:07,542 but Saturn does. 357 00:20:07,567 --> 00:20:10,299 So maybe there's some sort of interaction between 358 00:20:10,366 --> 00:20:14,836 the atmosphere of Titan and Saturn's giant magnetic field. 359 00:20:14,859 --> 00:20:16,742 The atmosphere of Titan and Saturn's giant magnetic field. 360 00:20:16,767 --> 00:20:20,142 The gas giant Saturn generates a magnetic field 361 00:20:20,165 --> 00:20:23,165 around 600 times larger than Earth's, 362 00:20:25,666 --> 00:20:29,366 large enough to shield Titan from the solar wind. 363 00:20:31,700 --> 00:20:35,041 So Titan by itself is vulnerable. 364 00:20:35,066 --> 00:20:36,900 Saturn is like the mother ship. 365 00:20:37,000 --> 00:20:39,500 It has this giant force field 366 00:20:39,567 --> 00:20:41,000 that it can use to protect Titan. 367 00:20:42,400 --> 00:20:44,836 Despite Saturn's embrace, Titan still loses 368 00:20:44,859 --> 00:20:48,299 Despite Saturn's embrace, Titan still loses 369 00:20:48,366 --> 00:20:52,567 some of its atmosphere, because occasionally, 370 00:20:52,666 --> 00:20:57,165 the moon wanders away from its protective parent. 371 00:20:57,266 --> 00:21:00,643 Titan orbits inside of that magnetic field... 372 00:21:00,666 --> 00:21:03,241 mostly, most of the time. 373 00:21:03,266 --> 00:21:05,000 Its orbit isn't perfectly circular. 374 00:21:05,099 --> 00:21:06,700 It's slightly elliptical. 375 00:21:08,467 --> 00:21:11,643 So as Titan orbits the planet, for a little bit of time, 376 00:21:11,666 --> 00:21:13,000 about 5 percent of its orbit, 377 00:21:13,066 --> 00:21:14,836 it's actually slightly outside the magnetic field 378 00:21:14,859 --> 00:21:15,443 it's actually slightly outside the magnetic field 379 00:21:15,468 --> 00:21:17,099 before dipping back in again. 380 00:21:19,666 --> 00:21:21,099 But these short forays into 381 00:21:21,165 --> 00:21:25,666 the firing line don't cause any lasting damage. 382 00:21:26,967 --> 00:21:30,165 What's really weird is that there's sort of a residual 383 00:21:30,266 --> 00:21:32,241 magnetic effect on Titan. 384 00:21:32,266 --> 00:21:34,542 When it leaves Saturn's protective field, 385 00:21:34,567 --> 00:21:37,000 it should just immediately drop to nothing. 386 00:21:37,066 --> 00:21:39,299 But there still is this residual field, 387 00:21:39,366 --> 00:21:41,843 protecting it from the solar wind. 388 00:21:41,866 --> 00:21:44,836 It can maintain the memory of that magnetic field 389 00:21:44,859 --> 00:21:45,099 It can maintain the memory of that magnetic field 390 00:21:45,165 --> 00:21:48,000 and still preserve some of that protection. 391 00:21:49,299 --> 00:21:52,099 It's almost like Saturn is trying to teach 392 00:21:52,165 --> 00:21:54,142 Titan how to have a magnetic field, 393 00:21:54,165 --> 00:21:56,000 and Titan can remember for a little bit, 394 00:21:56,066 --> 00:21:58,000 but then it needs to come back home. 395 00:21:59,866 --> 00:22:02,366 This magnetic memory could help 396 00:22:02,467 --> 00:22:05,599 support any life on Titan's surface, 397 00:22:05,666 --> 00:22:09,666 providing a safe haven that's protected from the solar wind. 398 00:22:12,266 --> 00:22:14,200 And Cassini spots a way 399 00:22:14,266 --> 00:22:14,836 Saturn's magnetism might also allow 400 00:22:14,861 --> 00:22:17,366 Saturn's magnetism might also allow 401 00:22:17,467 --> 00:22:20,643 its moons to develop life. 402 00:22:20,666 --> 00:22:24,767 One of the most amazing discoveries around Saturn was 403 00:22:24,866 --> 00:22:26,500 that its magnetic field is not 404 00:22:26,567 --> 00:22:28,666 just transporting charged particles from, 405 00:22:28,767 --> 00:22:32,266 say, the sun, but it's also transporting material 406 00:22:32,366 --> 00:22:33,799 from one moon to another. 407 00:22:37,165 --> 00:22:39,542 Saturn's magnetic field helps boost 408 00:22:39,567 --> 00:22:41,843 the chance of life on Titan 409 00:22:41,866 --> 00:22:44,836 by stealing material from its sister moon, Enceladus. 410 00:22:44,859 --> 00:22:46,940 By stealing material from its sister moon, Enceladus. 411 00:22:48,165 --> 00:22:50,643 Magnetism is a strong force, of course, 412 00:22:50,666 --> 00:22:53,542 but to act on a scale and a range 413 00:22:53,567 --> 00:22:56,299 like this and maybe transport matter from moon to moon, 414 00:22:56,366 --> 00:22:58,066 that's pretty cool. 415 00:22:59,799 --> 00:23:02,866 Saturn's magnetic field smashes apart 416 00:23:02,967 --> 00:23:07,366 water molecules blasted out from Enceladus's geysers 417 00:23:07,467 --> 00:23:12,599 and carries the leftover oxygen to Titan. 418 00:23:12,666 --> 00:23:14,767 The magnetic field of Saturn 419 00:23:14,866 --> 00:23:18,099 acts like an inter-lunar highway 420 00:23:18,165 --> 00:23:21,643 in the Saturn system, transporting oxygen 421 00:23:21,666 --> 00:23:24,500 from Enceladus all the way to Titan. 422 00:23:24,567 --> 00:23:28,165 But there's a problem when the oxygen tries to 423 00:23:28,266 --> 00:23:33,041 take the Titan exit off of this inter-lunar highway. 424 00:23:33,066 --> 00:23:36,200 Normally, this oxygen wouldn't survive 425 00:23:36,266 --> 00:23:37,567 in the atmosphere of Titan. 426 00:23:37,666 --> 00:23:40,467 It would react with the methane there and create carbon dioxide. 427 00:23:41,967 --> 00:23:43,700 To get to the surface 428 00:23:43,767 --> 00:23:44,836 in one piece, oxygen hitches 429 00:23:44,859 --> 00:23:46,142 in one piece, oxygen hitches 430 00:23:46,165 --> 00:23:49,567 a ride with something called a fullerene. 431 00:23:54,467 --> 00:23:55,942 Fullerenes are these sort of 432 00:23:55,967 --> 00:23:58,500 soccer ball shaped molecules that are hollow. 433 00:23:58,567 --> 00:24:00,643 If the oxygen atom gets in there, 434 00:24:00,666 --> 00:24:03,866 it can be safely transported through Titan's atmosphere. 435 00:24:05,767 --> 00:24:09,599 Once on the surface, the oxygen could help create 436 00:24:09,666 --> 00:24:11,442 amino acids, 437 00:24:11,467 --> 00:24:14,400 the essential building blocks of proteins, 438 00:24:14,467 --> 00:24:14,836 another stepping stone for life to emerge. 439 00:24:14,861 --> 00:24:19,099 Another stepping stone for life to emerge. 440 00:24:22,366 --> 00:24:25,767 Think of all the complex coincidences 441 00:24:25,866 --> 00:24:27,567 that have to happen 442 00:24:27,666 --> 00:24:30,643 for these chemical reactions to take place. 443 00:24:30,666 --> 00:24:32,666 If Titan's orbit was any different, 444 00:24:32,767 --> 00:24:34,099 it simply wouldn't exist. 445 00:24:37,767 --> 00:24:42,366 Saturn protects any potential life on its moons. 446 00:24:43,599 --> 00:24:44,836 And as it turns out, the moons 447 00:24:44,859 --> 00:24:46,142 And as it turns out, the moons 448 00:24:46,165 --> 00:24:50,666 return the favor by helping create 449 00:24:50,767 --> 00:24:57,000 and maintain Saturn's iconic rings. 450 00:25:10,467 --> 00:25:13,799 At 170,000 miles in diameter, 451 00:25:15,000 --> 00:25:17,500 but only 30 feet thick in places, 452 00:25:17,567 --> 00:25:22,366 Saturn's beautiful rings have always stolen the show, 453 00:25:25,266 --> 00:25:29,366 but their origin is still a mystery. 454 00:25:29,467 --> 00:25:29,942 Saturn has these beautiful rings that really 455 00:25:29,965 --> 00:25:33,041 Saturn has these beautiful rings that really 456 00:25:33,066 --> 00:25:34,299 define it as a planet, 457 00:25:34,366 --> 00:25:36,527 but its unique in the solar system in the sense that no 458 00:25:36,567 --> 00:25:40,099 other planet has such a big ring system. 459 00:25:40,165 --> 00:25:44,099 All of the other gas giants have remnants of a ring, 460 00:25:44,165 --> 00:25:47,942 kind of small, thin, dark rings, but nothing like Saturn. 461 00:25:47,967 --> 00:25:51,000 So something very different happened around Saturn. 462 00:25:53,000 --> 00:25:57,599 A clue comes from the rings' composition. 463 00:25:57,666 --> 00:25:59,941 They're around 99 percent water ice, 464 00:25:59,964 --> 00:26:00,500 They're around 99 percent water ice, 465 00:26:00,567 --> 00:26:03,467 giving the rings their sparkling appearance. 466 00:26:05,000 --> 00:26:09,400 This leads astronomers to a bold theory. 467 00:26:09,467 --> 00:26:13,099 We do not know how Saturn's icy rings formed. 468 00:26:13,165 --> 00:26:14,742 We're not even sure how old they are, 469 00:26:14,767 --> 00:26:18,266 but one idea is that they formed from ice that was 470 00:26:18,366 --> 00:26:20,567 existing previously on a moon. 471 00:26:20,666 --> 00:26:23,400 How amazing is that? 472 00:26:23,467 --> 00:26:28,467 Several billion years ago, Saturn may have been ringless, 473 00:26:29,666 --> 00:26:29,942 with a large, icy moon. 474 00:26:29,965 --> 00:26:32,165 With a large, icy moon. 475 00:26:32,266 --> 00:26:35,866 The moon was big enough that its gravity drew heavier 476 00:26:35,967 --> 00:26:37,742 stuff like rock to its core 477 00:26:37,767 --> 00:26:40,467 and lighter stuff like ice floated to the top. 478 00:26:40,567 --> 00:26:47,241 We think the moon strayed too close to Saturn. 479 00:26:47,266 --> 00:26:50,366 The gravity from Saturn could tear it apart, 480 00:26:52,200 --> 00:26:55,241 and it could separate the ices from the rocky parts 481 00:26:55,266 --> 00:26:57,742 and the ices could stay in orbit and form our rings, 482 00:26:57,767 --> 00:26:59,941 and the rocky parts would get swallowed up by Saturn. 483 00:26:59,964 --> 00:27:02,045 And the rocky parts would get swallowed up by Saturn. 484 00:27:07,066 --> 00:27:10,666 The death of a large moon may have built the rings, 485 00:27:14,866 --> 00:27:18,942 but they owe their current appearance to the moons that 486 00:27:18,967 --> 00:27:20,900 are still alive. 487 00:27:21,000 --> 00:27:24,241 When you go back to Saturn's rings, 488 00:27:24,266 --> 00:27:27,099 time and time again, they're all slightly different. 489 00:27:27,165 --> 00:27:29,142 They are changing, they are braiding in and out of 490 00:27:29,165 --> 00:27:29,942 each other... we had no idea there would be 491 00:27:29,965 --> 00:27:32,000 each other... we had no idea there would be 492 00:27:32,099 --> 00:27:34,567 so much beauty and so much mystery in the rings. 493 00:27:36,467 --> 00:27:40,241 The behavior of two of Saturn's moons, 494 00:27:40,266 --> 00:27:42,567 Prometheus and Atlas, 495 00:27:42,666 --> 00:27:45,099 which are embedded in the rings 496 00:27:45,165 --> 00:27:47,299 is especially surprising. 497 00:27:47,366 --> 00:27:50,567 Some of these smallest moons 498 00:27:50,666 --> 00:27:53,467 are interspersed within the ring system. 499 00:27:53,567 --> 00:27:57,767 Some of them are doing something really bizarre. 500 00:27:57,866 --> 00:27:59,941 In some cases, it looks like the moons were shepherding 501 00:27:59,964 --> 00:28:01,241 In some cases, it looks like the moons were shepherding 502 00:28:01,266 --> 00:28:04,767 the edges of the rings and keeping them in their place. 503 00:28:06,000 --> 00:28:09,567 The moon's gravity cleans up the rings, 504 00:28:10,866 --> 00:28:14,366 sometimes, sculpting shapes in their wake. 505 00:28:16,666 --> 00:28:19,542 Saturn's rings aren't static, and there's some really 506 00:28:19,567 --> 00:28:22,500 fascinating interactions where moons are clearly pushing on 507 00:28:22,567 --> 00:28:25,467 the rings and causing weird and cool waves, 508 00:28:25,567 --> 00:28:29,900 making the rings just that much more beautiful. 509 00:28:30,000 --> 00:28:33,343 The whole dance between Saturn and its moons, 510 00:28:33,366 --> 00:28:35,165 its rings, how they all 511 00:28:35,266 --> 00:28:37,900 are interconnected, is just completely fascinating. 512 00:28:40,099 --> 00:28:41,666 It's a dynamic, amazing, 513 00:28:41,767 --> 00:28:44,200 living, geologically vibrant place. 514 00:28:48,266 --> 00:28:51,266 Saturn's moons may keep the rings orderly, 515 00:28:53,200 --> 00:28:58,142 but they can't explain why the rings are so clean, 516 00:28:58,165 --> 00:28:59,666 almost pristine. 517 00:29:02,099 --> 00:29:03,643 They're too shiny. 518 00:29:03,666 --> 00:29:06,099 If they were billions of years old, 519 00:29:06,165 --> 00:29:08,500 they should have collected a lot of dust by now 520 00:29:08,567 --> 00:29:09,767 and be a lot darker. 521 00:29:09,866 --> 00:29:12,742 The fact that they're shiny kind of implies that 522 00:29:12,767 --> 00:29:16,599 maybe they're a lot younger than we first thought. 523 00:29:16,666 --> 00:29:19,442 Perhaps the rings we see today 524 00:29:19,467 --> 00:29:22,366 are a more recent upgrade. 525 00:29:23,866 --> 00:29:26,643 The rings might only be 100 million years old, 526 00:29:26,666 --> 00:29:28,799 about the time of the dinosaurs. 527 00:29:28,866 --> 00:29:29,941 So if the dinosaurs had invented telescopes, 528 00:29:29,964 --> 00:29:31,866 So if the dinosaurs had invented telescopes, 529 00:29:31,967 --> 00:29:34,843 they could have seen Saturn without rings. 530 00:29:34,866 --> 00:29:36,142 And it makes you wonder, is this 531 00:29:36,165 --> 00:29:38,142 the first ring system that Saturn had? 532 00:29:38,165 --> 00:29:39,942 Or was there another ring system 533 00:29:39,967 --> 00:29:42,000 that may be slowly eroded away? 534 00:29:42,099 --> 00:29:45,266 Perhaps a comet or a body came in too close to Saturn, 535 00:29:45,366 --> 00:29:47,343 and Saturn's gravity literally tore it apart, 536 00:29:47,366 --> 00:29:49,200 and then we got a brand-new ring system. 537 00:29:51,567 --> 00:29:54,299 The later dinosaurs could have watched the rings form, 538 00:29:55,467 --> 00:29:57,626 and then they would have been wiped out by an asteroid. 539 00:29:58,567 --> 00:29:59,941 Yeah, should have built better telescopes, 540 00:29:59,964 --> 00:30:00,344 Yeah, should have built better telescopes, 541 00:30:00,367 --> 00:30:02,866 dinosaurs, sucks to be you. 542 00:30:05,567 --> 00:30:08,599 We still don't know why the rings of Saturn 543 00:30:08,666 --> 00:30:10,266 are so clean. 544 00:30:11,967 --> 00:30:14,142 It could be that the rings really are old, and they have 545 00:30:14,165 --> 00:30:15,500 some sort of cleaning system, 546 00:30:15,567 --> 00:30:17,000 which removes the dust from them, 547 00:30:17,066 --> 00:30:21,599 making them look young, or they may actually be young, and this 548 00:30:21,666 --> 00:30:24,843 may be the seventh or eighth or whatever generation rings. 549 00:30:24,866 --> 00:30:29,941 It is so different than any other planetary system. 550 00:30:29,964 --> 00:30:29,943 It is so different than any other planetary system. 551 00:30:29,968 --> 00:30:31,866 And those mysteries still exist. 552 00:30:31,967 --> 00:30:35,666 We have some idea what went on, 553 00:30:35,767 --> 00:30:38,066 but there's a lot that we don't know about Saturn. 554 00:30:40,866 --> 00:30:43,599 Cassini is changing that. 555 00:30:46,000 --> 00:30:50,000 It's discovered a whole new moon-making process, 556 00:30:52,165 --> 00:30:55,000 with the rings taking the lead. 557 00:31:10,967 --> 00:31:13,767 Midway through its 13-year mission to Saturn, 558 00:31:16,165 --> 00:31:19,000 Cassini captures an intriguing image, 559 00:31:21,666 --> 00:31:23,700 a bright feature at the edge 560 00:31:23,767 --> 00:31:26,000 of one of Saturn's outermost rings, 561 00:31:27,066 --> 00:31:29,000 something we'd never seen before. 562 00:31:31,400 --> 00:31:34,599 I was really excited when we saw these images of Saturn's 563 00:31:34,666 --> 00:31:36,942 rings, and it looked like there was a lump, 564 00:31:36,967 --> 00:31:41,599 maybe a moon forming there, which they nicknamed Peggy. 565 00:31:41,666 --> 00:31:43,666 Named after the mother-in-law 566 00:31:43,767 --> 00:31:45,799 of the scientist who discovered it, 567 00:31:45,866 --> 00:31:49,200 Peggy was still too small to be considered 568 00:31:49,266 --> 00:31:54,942 a fully-formed moon, but nearby orbits 569 00:31:54,967 --> 00:31:59,299 a group of objects that are just big enough to be moons, 570 00:32:02,165 --> 00:32:04,299 and they are really weird. 571 00:32:05,900 --> 00:32:07,467 These moons are really unusual. 572 00:32:07,567 --> 00:32:10,467 We don't think of them as like anything else we've seen. 573 00:32:10,567 --> 00:32:14,165 They're kind of little fuzzy potatoes or maybe 574 00:32:14,266 --> 00:32:17,343 even like a ravioli is another one or a croissant. 575 00:32:17,366 --> 00:32:18,643 Why do we always come up with food? 576 00:32:18,666 --> 00:32:22,000 But at the same time, that's exactly what they look like. 577 00:32:22,066 --> 00:32:25,366 The most bizarrely-shaped moon of Saturn is Pan. 578 00:32:25,467 --> 00:32:27,200 It's got these crisscrossing cracks, 579 00:32:27,266 --> 00:32:30,099 just like bread, and then around the outside 580 00:32:30,165 --> 00:32:32,343 is a belly band, it's undulatory. 581 00:32:32,366 --> 00:32:34,000 How would this get there? 582 00:32:36,700 --> 00:32:39,266 Cassini discovered a clue. 583 00:32:42,099 --> 00:32:44,200 Like Saturn's rings, 584 00:32:44,266 --> 00:32:48,165 these moons were made almost entirely of water ice. 585 00:32:51,165 --> 00:32:52,343 They must have grown from 586 00:32:52,366 --> 00:32:55,567 tiny lumps trapped within the rings. 587 00:32:56,666 --> 00:33:00,134 They're going to be extremely fragile, 588 00:33:00,157 --> 00:33:02,767 They're going to be extremely fragile, 589 00:33:02,866 --> 00:33:05,400 kind of like a snowflake orbiting Saturn. 590 00:33:05,467 --> 00:33:08,366 They can start drawing in material and then can grow. 591 00:33:08,467 --> 00:33:10,942 You can actually imagine rolling up a snowball 592 00:33:10,967 --> 00:33:13,843 and accumulating more and more particles on the outside. 593 00:33:13,866 --> 00:33:16,400 And in the same way, you could accumulate 594 00:33:16,467 --> 00:33:17,866 these clumps in the rings. 595 00:33:17,967 --> 00:33:19,866 And if they're near the edge of the rings, 596 00:33:19,967 --> 00:33:24,567 perhaps they actually break free and go out to form tiny moons. 597 00:33:27,266 --> 00:33:30,134 The size of these space snowballs, 598 00:33:30,157 --> 00:33:30,666 The size of these space snowballs, 599 00:33:30,767 --> 00:33:33,866 tens of miles across or less, 600 00:33:33,967 --> 00:33:36,467 helps explain their unusual shapes. 601 00:33:39,799 --> 00:33:43,542 The size of the moon actually affects its shape in that once 602 00:33:43,567 --> 00:33:45,099 you get below a certain size threshold, 603 00:33:45,165 --> 00:33:46,900 you cannot be round anymore. 604 00:33:47,000 --> 00:33:48,843 That's because the strength of the rock or the ice 605 00:33:48,866 --> 00:33:51,643 in this case is too great to be overcome by gravity, 606 00:33:51,666 --> 00:33:54,767 and so the kind of oblong shapes can be maintained. 607 00:33:57,200 --> 00:33:59,266 Add in a few collisions, 608 00:33:59,366 --> 00:34:00,134 and you get Saturn's ravioli- and croissant-shaped moons. 609 00:34:00,159 --> 00:34:03,467 And you get Saturn's ravioli- and croissant-shaped moons. 610 00:34:06,266 --> 00:34:08,666 It's a bizarre process but leads to a beautiful form. 611 00:34:08,766 --> 00:34:12,766 We know the moons affect the rings, but it looks 612 00:34:12,867 --> 00:34:15,443 like in this case, the rings affect the moons, too. 613 00:34:15,467 --> 00:34:17,500 They're connected in both directions. 614 00:34:23,367 --> 00:34:26,467 The rings form a moon factory, 615 00:34:30,467 --> 00:34:34,467 capable of building countless generations of new worlds. 616 00:34:36,467 --> 00:34:40,000 This is a dance of physics. 617 00:34:42,000 --> 00:34:45,367 If moonlets can form by these icy ring particles, 618 00:34:45,467 --> 00:34:47,742 they'll grow, and then their natural gravitational 619 00:34:47,766 --> 00:34:50,300 interaction with the rings will make them move out. 620 00:34:50,367 --> 00:34:51,900 They keep growing as they move out. 621 00:34:52,000 --> 00:34:54,467 But then another moon forms where the first one was. 622 00:34:54,567 --> 00:34:57,443 So you keep getting these growing moons, right, 623 00:34:57,467 --> 00:34:59,800 and this process repeats like on a conveyor belt. 624 00:34:59,867 --> 00:35:00,135 And what you wind up with is bigger moons orbiting 625 00:35:00,159 --> 00:35:02,443 And what you wind up with is bigger moons orbiting 626 00:35:02,467 --> 00:35:04,699 farther out from Saturn and smaller ones 627 00:35:04,766 --> 00:35:06,000 orbiting closer in. 628 00:35:08,867 --> 00:35:12,567 But Saturn's conveyor belt will eventually break down. 629 00:35:17,166 --> 00:35:18,599 When ultraviolet light from 630 00:35:18,666 --> 00:35:23,000 the sun interacts with ring particles, 631 00:35:23,065 --> 00:35:27,199 it throws their steady orbit around Saturn out of whack. 632 00:35:29,467 --> 00:35:30,135 The sun energizes the rings, and it gives them a charge. 633 00:35:30,159 --> 00:35:32,543 The sun energizes the rings, and it gives them a charge. 634 00:35:32,567 --> 00:35:34,141 This charge means they can get picked 635 00:35:34,166 --> 00:35:36,342 up by the magnetic field of Saturn. 636 00:35:36,367 --> 00:35:38,900 So these little tiny charged particles then are lifted 637 00:35:39,000 --> 00:35:40,266 out of the rings, 638 00:35:40,367 --> 00:35:42,400 follow along the magnetic field lines, 639 00:35:42,467 --> 00:35:44,567 rain down into Saturn's atmosphere. 640 00:35:47,166 --> 00:35:51,900 The charged particles are tiny ice crystals. 641 00:35:52,000 --> 00:35:54,599 They rain down onto Saturn, 642 00:35:57,266 --> 00:36:00,134 enough to fill an Olympic-sized swimming pool 643 00:36:00,157 --> 00:36:00,500 enough to fill an Olympic-sized swimming pool 644 00:36:00,567 --> 00:36:01,666 every second. 645 00:36:05,467 --> 00:36:08,199 In less than 100 million years, 646 00:36:08,266 --> 00:36:12,300 Saturn's rings will be gone. 647 00:36:12,367 --> 00:36:17,643 There will be no material to build new moons. 648 00:36:17,666 --> 00:36:21,467 Saturn's moons and rings, 649 00:36:21,567 --> 00:36:23,699 they almost make me feel bittersweet, because they 650 00:36:23,766 --> 00:36:26,666 show you the beauty of what physics can create, 651 00:36:26,766 --> 00:36:28,742 But also the fleeting-ness. 652 00:36:28,766 --> 00:36:30,134 They'll be gone soon, and that makes me sad. 653 00:36:30,157 --> 00:36:31,878 They'll be gone soon, and that makes me sad. 654 00:36:34,666 --> 00:36:36,599 The closer we look, 655 00:36:36,666 --> 00:36:39,567 the more intriguing the Saturn system becomes. 656 00:36:45,900 --> 00:36:48,099 And now, scientists 657 00:36:48,166 --> 00:36:50,266 have an audacious new plan 658 00:36:53,567 --> 00:36:57,666 to fly a drone on one of Saturn's moons. 659 00:37:09,467 --> 00:37:12,543 Saturn is one of the most dynamic places 660 00:37:12,567 --> 00:37:15,199 in the solar system. 661 00:37:16,367 --> 00:37:18,166 We want to go back there, 662 00:37:18,266 --> 00:37:21,141 to explore its moons up close 663 00:37:21,166 --> 00:37:24,400 and hunt directly for Life 2.0. 664 00:37:26,967 --> 00:37:29,199 For so long, we've been emphasizing that to have 665 00:37:29,266 --> 00:37:30,327 a habitable planet, 666 00:37:30,351 --> 00:37:30,467 a habitable planet, 667 00:37:30,500 --> 00:37:32,659 you have to be warm, you have to be close to your star. 668 00:37:33,867 --> 00:37:36,099 In fact, the most likely chance we have to find 669 00:37:36,166 --> 00:37:39,567 life maybe way in the outer solar system in Saturn's moons. 670 00:37:40,599 --> 00:37:43,266 But we won't know for sure until we send 671 00:37:43,367 --> 00:37:45,666 another mission there, specifically to look for life. 672 00:37:47,467 --> 00:37:49,300 The Huygens Probe gave us 673 00:37:49,367 --> 00:37:52,000 a tantalizing glimpse of Titan's surface, 674 00:37:56,000 --> 00:37:59,065 but it wasn't equipped to search for life. 675 00:38:00,867 --> 00:38:05,300 Now, scientists are developing Dragonfly, 676 00:38:05,367 --> 00:38:10,000 a space helicopter that can search for life. 677 00:38:12,099 --> 00:38:14,199 Dragonfly is an amazing mission. 678 00:38:14,266 --> 00:38:16,367 We're sending this to Titan to better 679 00:38:16,467 --> 00:38:19,166 understand how life might arise in a very different 680 00:38:19,266 --> 00:38:20,266 context than Earth. 681 00:38:22,766 --> 00:38:24,666 One thing we know absolutely for certain 682 00:38:24,766 --> 00:38:28,367 is that Titan has interesting, complex chemistry. 683 00:38:28,467 --> 00:38:29,666 The question now is, 684 00:38:29,766 --> 00:38:30,327 does that chemistry actually turn into biology? 685 00:38:30,351 --> 00:38:33,000 Does that chemistry actually turn into biology? 686 00:38:36,567 --> 00:38:40,367 The million-dollar question, is this a living world? 687 00:38:47,300 --> 00:38:50,666 April 2021. 688 00:38:53,000 --> 00:38:56,467 We test the concept of a space helicopter. 689 00:39:01,099 --> 00:39:04,000 Ingenuity making the first remote flight on 690 00:39:04,065 --> 00:39:08,300 another world launches into the thin Martian atmosphere. 691 00:39:10,266 --> 00:39:12,367 Mars is a really difficult place to fly, 692 00:39:12,467 --> 00:39:16,266 because the atmosphere is 100 times thinner than Earth's. 693 00:39:16,367 --> 00:39:18,599 And remember, it's the atmosphere that provides 694 00:39:18,666 --> 00:39:21,766 the support and the lift for a helicopter to fly. 695 00:39:21,867 --> 00:39:23,242 So in order for Ingenuity to fly, 696 00:39:23,266 --> 00:39:25,500 it had to spin very fast in order 697 00:39:25,567 --> 00:39:27,000 to even get itself off the ground. 698 00:39:31,666 --> 00:39:34,666 Fortunately, Titan's thick atmosphere 699 00:39:34,766 --> 00:39:37,166 is much more helicopter friendly. 700 00:39:39,666 --> 00:39:42,500 The contrast between Ingenuity and the Dragonfly mission 701 00:39:42,567 --> 00:39:43,443 is really funny, 702 00:39:43,467 --> 00:39:46,400 because Mars has almost no atmosphere, 703 00:39:46,467 --> 00:39:48,900 less than 1 percent the atmospheric pressure of Earth. 704 00:39:49,000 --> 00:39:52,141 On Titan, you have exactly the opposite. 705 00:39:52,166 --> 00:39:54,242 The air pressure near the surface of Titan can be 706 00:39:54,266 --> 00:39:56,842 four times as much as the air pressure on Earth. 707 00:39:56,867 --> 00:39:59,599 So for a helicopter or something like a drone, 708 00:39:59,666 --> 00:40:00,327 something like an octocopter, 709 00:40:00,351 --> 00:40:00,800 something like an octocopter, 710 00:40:00,867 --> 00:40:04,099 the lower the gravity is and the denser the atmosphere, 711 00:40:04,166 --> 00:40:05,367 the better you can fly. 712 00:40:06,199 --> 00:40:09,141 So Titan just begs to be explored, because you get 713 00:40:09,166 --> 00:40:11,099 a lot of lift, and you can actually carry heavy 714 00:40:11,166 --> 00:40:12,166 instruments with you. 715 00:40:13,500 --> 00:40:16,099 It allows you to fly through the atmosphere, 716 00:40:16,166 --> 00:40:19,342 collect samples, and determine what the prebiotic chemistry 717 00:40:19,367 --> 00:40:20,467 is on that moon. 718 00:40:22,467 --> 00:40:25,041 If ever there was a world built for flying drones, 719 00:40:25,065 --> 00:40:27,099 it's Titan. 720 00:40:27,166 --> 00:40:30,327 Dragonfly is scheduled to launch in 2027, 721 00:40:30,351 --> 00:40:31,951 Dragonfly is scheduled to launch in 2027, 722 00:40:34,000 --> 00:40:36,766 arriving at Titan around seven years later, 723 00:40:36,867 --> 00:40:41,099 completing the journey of moon discovery that began 724 00:40:41,166 --> 00:40:43,567 with Voyager and Cassini. 725 00:40:46,065 --> 00:40:47,742 We completely transformed 726 00:40:47,766 --> 00:40:51,141 our picture of the Saturn system, the rings and the moons. 727 00:40:51,166 --> 00:40:52,842 It's a far more complex 728 00:40:52,867 --> 00:40:55,141 environment than we ever dreamed possible. 729 00:40:55,166 --> 00:40:56,699 The moons have come alive, right? 730 00:40:56,766 --> 00:40:59,867 They're not boring, dead ice balls, and it just 731 00:40:59,967 --> 00:41:00,327 begs generation after generation of spacecraft follow up. 732 00:41:00,351 --> 00:41:02,592 Begs generation after generation of spacecraft follow up. 733 00:41:05,300 --> 00:41:06,742 We're only just beginning to 734 00:41:06,766 --> 00:41:09,666 unravel the secrets of Saturn's moons. 735 00:41:12,099 --> 00:41:16,367 And with more than 80 to explore, the Saturn system is 736 00:41:16,467 --> 00:41:19,000 a gift that'll keep on giving. 737 00:41:21,900 --> 00:41:24,567 Saturn was the very first thing I ever 738 00:41:24,666 --> 00:41:26,543 saw through a telescope when I was a kid. 739 00:41:26,567 --> 00:41:30,327 And here I am... clearly, I was inspired by Saturn, 740 00:41:30,351 --> 00:41:30,467 And here I am... clearly, I was inspired by Saturn, 741 00:41:30,567 --> 00:41:32,400 by its beauty. 742 00:41:32,467 --> 00:41:34,742 Saturn has always been my favorite planet. 743 00:41:34,766 --> 00:41:36,099 Everything you want 744 00:41:36,166 --> 00:41:38,943 is there... violence, colliding moons, 745 00:41:38,967 --> 00:41:42,500 how new rings form, new moons form over time. 746 00:41:43,867 --> 00:41:45,543 And there might be life there. 747 00:41:45,567 --> 00:41:49,000 There might be life in more than one place there. 748 00:41:49,065 --> 00:41:53,000 One destination, one planetary zip code, gives you all of that. 749 00:41:53,065 --> 00:41:54,500 I say go back to Saturn. 59512

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