All language subtitles for How the Universe Works (2010) - S01E02 - Black Holes (1080p BluRay x265 Garshasp)

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These are the user uploaded subtitles that are being translated: 1 00:00:02,736 --> 00:00:04,795 Narrator: The universe is home to real monsters. 2 00:00:04,805 --> 00:00:07,866 We can't see them, but we know they're out there. 3 00:00:07,875 --> 00:00:12,073 You really can't get anything bigger or stronger or scarier 4 00:00:12,079 --> 00:00:13,478 than a black hole. 5 00:00:13,481 --> 00:00:17,782 Narrator: Black holes consume planets and stars -- 6 00:00:17,785 --> 00:00:20,846 anything that gets too close. 7 00:00:20,855 --> 00:00:23,119 Black holes give physicists no end of headaches, 8 00:00:23,123 --> 00:00:24,989 'cause they break all the rules. 9 00:00:24,992 --> 00:00:30,158 Narrator: But they rule the universe. 10 00:00:30,164 --> 00:00:31,529 They are center-stage. 11 00:00:33,133 --> 00:00:34,965 We now know they dominate 12 00:00:34,969 --> 00:00:38,098 the evolution of the universe itself. 13 00:00:59,193 --> 00:01:01,992 Narrator: Black holes are the most mysterious objects 14 00:01:01,996 --> 00:01:03,725 in our universe. 15 00:01:03,731 --> 00:01:07,065 Their gravity is absolute. 16 00:01:09,270 --> 00:01:13,138 Nothing can escape. 17 00:01:13,140 --> 00:01:17,737 They can suck in whole galaxies. 18 00:01:17,745 --> 00:01:21,010 Black holes used to be science fiction. 19 00:01:21,015 --> 00:01:23,541 Now we know they're real. 20 00:01:23,551 --> 00:01:25,110 When I was a PhD student, 21 00:01:25,119 --> 00:01:28,555 people used to giggle when you'd hear about black holes. 22 00:01:28,556 --> 00:01:31,218 They're like unicorns, mythical creatures. 23 00:01:31,225 --> 00:01:32,989 We called this the "giggle factor." 24 00:01:32,993 --> 00:01:34,927 People would say, "Beam me up, Scotty." 25 00:01:34,929 --> 00:01:37,796 Well, no one is laughing anymore. 26 00:01:39,099 --> 00:01:41,500 Krauss: So, they're not science fiction. 27 00:01:41,502 --> 00:01:43,630 Even though we've never landed in one, 28 00:01:43,637 --> 00:01:46,038 we have enough evidence to know that they're really out there. 29 00:01:51,979 --> 00:01:55,244 Narrator: This image might not look like much to you and me, 30 00:01:55,249 --> 00:01:59,982 but to a scientist, it's proof that black holes exist. 31 00:01:59,987 --> 00:02:04,549 It's an actual movie of a black hole devouring a star 32 00:02:04,558 --> 00:02:07,186 in the constellation of Aquila. 33 00:02:07,194 --> 00:02:09,356 Black holes are messy eaters. 34 00:02:09,363 --> 00:02:11,730 The red spots you see are gas 35 00:02:11,732 --> 00:02:16,226 that's being spit out of the hole, into space. 36 00:02:16,236 --> 00:02:19,331 Eventually, over the next million years, 37 00:02:19,340 --> 00:02:24,141 this star will be eaten alive and disappear. 38 00:02:32,386 --> 00:02:34,787 A black hole is pretty much the end point of everything. 39 00:02:34,788 --> 00:02:37,280 It's the end point of a star. It's the end point of matter. 40 00:02:37,291 --> 00:02:39,885 It's the end point of energy. It's the end point of gravity. 41 00:02:39,893 --> 00:02:44,490 I mean, that's really it. That's the top of the scale. 42 00:02:49,136 --> 00:02:51,571 Narrator: Although they have the power to destroy 43 00:02:51,572 --> 00:02:53,370 like nothing else in the universe, 44 00:02:53,374 --> 00:02:57,436 black holes also help build galaxies -- 45 00:02:57,444 --> 00:03:01,438 a vital part of the great cosmic machine. 46 00:03:01,448 --> 00:03:03,439 Some astronomers think 47 00:03:03,450 --> 00:03:07,318 they could even be gateways to parallel universes. 48 00:03:12,526 --> 00:03:15,587 Dr. Kaku: We are now entering the golden age of research 49 00:03:15,596 --> 00:03:17,064 in black-hole physics. 50 00:03:17,064 --> 00:03:19,726 They could be the key 51 00:03:19,733 --> 00:03:22,566 to understanding the birth of the universe, 52 00:03:22,569 --> 00:03:24,833 its formation, and then its death. 53 00:03:29,777 --> 00:03:31,802 Dr. Krauss: Black holes really represent, 54 00:03:31,812 --> 00:03:34,110 in one sense, the frontier of modern astronomy. 55 00:03:34,114 --> 00:03:36,845 And they're changing our ideas about how galaxies form 56 00:03:36,850 --> 00:03:38,784 and, indeed, how the universe works. 57 00:03:38,786 --> 00:03:41,653 Narrator: Their power comes 58 00:03:41,655 --> 00:03:45,387 from one of the primary forces in nature -- gravity. 59 00:03:48,195 --> 00:03:50,493 Dr. Kaku: I teach astronomy. 60 00:03:50,497 --> 00:03:52,056 And we teach our students 61 00:03:52,066 --> 00:03:55,900 that the fundamental principle of gravity is, "gravity sucks." 62 00:03:55,903 --> 00:03:59,464 Narrator: Gravity keeps our feet on the ground 63 00:03:59,473 --> 00:04:02,499 and our planet orbiting around the Sun. 64 00:04:04,878 --> 00:04:10,442 But in a black hole, the force of gravity is off the charts -- 65 00:04:10,451 --> 00:04:14,183 so strong, it sucks in anything nearby. 66 00:04:14,188 --> 00:04:19,718 It can even bend the light from distant stars. 67 00:04:19,727 --> 00:04:22,719 And if that light gets too close, 68 00:04:22,730 --> 00:04:25,199 the black hole swallows it. 69 00:04:25,199 --> 00:04:26,928 Think of it like this. 70 00:04:26,934 --> 00:04:29,801 Imagine a black hole as a waterfall. 71 00:04:29,803 --> 00:04:33,205 Gravity is the river flowing toward the falls, 72 00:04:33,207 --> 00:04:35,608 and a beam of light -- the kayak. 73 00:04:35,609 --> 00:04:38,840 Upriver from the waterfall, the current is weak. 74 00:04:38,846 --> 00:04:42,407 The kayaker can paddle against it and get away. 75 00:04:42,416 --> 00:04:45,909 But closer to the waterfall, the current is stronger, 76 00:04:45,919 --> 00:04:50,880 and the kayaker struggles to escape. 77 00:04:50,891 --> 00:04:56,819 The edge of the waterfall is like the edge of a black hole. 78 00:04:56,830 --> 00:05:01,734 No matter how strong the kayaker is, he's going down. 79 00:05:01,735 --> 00:05:03,464 It's the same in space. 80 00:05:03,470 --> 00:05:06,633 The way black holes are really devastating 81 00:05:06,640 --> 00:05:08,972 is because when you get close to them, 82 00:05:08,976 --> 00:05:10,637 the gravity gets super-strong. 83 00:05:16,049 --> 00:05:19,041 Narrator: So strong that they eat light. 84 00:05:19,052 --> 00:05:21,987 That's why black holes are black. 85 00:05:27,361 --> 00:05:29,921 A black hole is like a roach motel. 86 00:05:29,930 --> 00:05:32,831 Everything checks in. Nothing checks out. 87 00:05:37,070 --> 00:05:40,165 Narrator: Anything that gets too close is doomed -- 88 00:05:40,174 --> 00:05:45,806 planets, stars, even whole solar systems. 89 00:05:52,653 --> 00:05:56,146 And don't think this is some faraway phenomenon. 90 00:05:56,156 --> 00:05:58,488 Black holes are on the loose 91 00:05:58,492 --> 00:06:02,326 right here in our own cosmic neighborhood. 92 00:06:02,329 --> 00:06:04,798 We now know there are wandering nomads 93 00:06:04,798 --> 00:06:07,028 throughout the Milky Way galaxy -- 94 00:06:07,034 --> 00:06:10,129 vagabonds throughout the galaxy, 95 00:06:10,137 --> 00:06:13,334 where black holes can come up right behind you 96 00:06:13,340 --> 00:06:16,105 and perhaps gobble you up, and they won't even burp. 97 00:06:16,109 --> 00:06:19,909 If one ever comes close, watch out. 98 00:06:19,913 --> 00:06:24,407 Narrator: If a black hole found its way into our solar system, 99 00:06:24,418 --> 00:06:26,147 it would rip us apart. 100 00:06:26,153 --> 00:06:28,110 Dr. Plait: Any kind of black hole 101 00:06:28,121 --> 00:06:30,453 that could pass through the solar system 102 00:06:30,457 --> 00:06:32,186 would be pulling on all the planets 103 00:06:32,192 --> 00:06:33,387 harder than the Sun does. 104 00:06:33,393 --> 00:06:35,259 And so it's just gonna totally disrupt 105 00:06:35,262 --> 00:06:37,492 the gravitational balance of the solar system. 106 00:06:37,497 --> 00:06:42,970 Narrator: The black hole would literally tear planets from their orbits 107 00:06:42,970 --> 00:06:45,098 and smash them into each other. 108 00:06:52,479 --> 00:06:56,507 It's just an epic disaster. It's a bull in a china shop. 109 00:07:00,821 --> 00:07:03,313 If it got close enough to, say, Jupiter, 110 00:07:03,323 --> 00:07:05,587 it could actually pull the moons of Jupiter 111 00:07:05,592 --> 00:07:06,753 away from the planet itself. 112 00:07:09,897 --> 00:07:12,229 It would just be flinging planets left and right 113 00:07:12,232 --> 00:07:14,564 everywhere as it whipped through the solar system, 114 00:07:14,568 --> 00:07:16,900 leaving disaster in its wake. 115 00:07:21,708 --> 00:07:24,734 Narrator: If a black hole approached Earth, 116 00:07:24,745 --> 00:07:28,443 all that gravity would rip asteroids from their orbits 117 00:07:28,448 --> 00:07:30,542 and hurl them toward our planet. 118 00:07:39,259 --> 00:07:42,229 The Earth's surface would become an inferno. 119 00:07:42,229 --> 00:07:45,927 It would be the beginning of the end. 120 00:07:50,604 --> 00:07:53,266 First, it would swallow up the atmosphere, 121 00:07:53,273 --> 00:07:55,765 then the planet itself. 122 00:08:01,148 --> 00:08:04,106 Destroying an entire solar system 123 00:08:04,117 --> 00:08:06,552 is nothing to a black hole. 124 00:08:06,553 --> 00:08:11,514 But it's more than just a big, empty, sucking piece of space. 125 00:08:11,525 --> 00:08:14,426 It's incredibly heavy. 126 00:08:14,428 --> 00:08:18,888 To get an idea just how heavy and dense a black hole is, 127 00:08:18,899 --> 00:08:20,594 imagine the Earth. 128 00:08:20,600 --> 00:08:23,865 Now start to crush it... 129 00:08:26,540 --> 00:08:29,976 ...and keep crushing until it's packed so tight 130 00:08:29,977 --> 00:08:33,072 even the atoms themselves coHapse. 131 00:08:35,983 --> 00:08:40,284 When the Earth crushes down to just 2 inches across, 132 00:08:40,287 --> 00:08:43,245 that's the density of a black hole. 133 00:08:43,256 --> 00:08:46,055 It would be the size of a golf ball, 134 00:08:46,059 --> 00:08:51,930 yet weigh the same as the Earth, with the same amount of gravity. 135 00:08:51,932 --> 00:08:55,800 What can make something that small, 136 00:08:55,802 --> 00:08:59,670 that dense, and that powerful? 137 00:08:59,673 --> 00:09:03,871 We don't have external forces, large pistons in the universe, 138 00:09:03,877 --> 00:09:05,470 to create black holes. 139 00:09:05,479 --> 00:09:08,244 So the only way the real black holes of the universe form 140 00:09:08,248 --> 00:09:10,273 is if gravity can do the job itself. 141 00:09:10,283 --> 00:09:14,151 Narrator: There is only one place in the universe 142 00:09:14,154 --> 00:09:16,953 that generates that much gravity. 143 00:09:16,957 --> 00:09:19,756 And it's inside the largest stars. 144 00:09:19,760 --> 00:09:25,096 When massive stars 10 times heavier than our sun die, 145 00:09:25,098 --> 00:09:27,123 gravity crushes them, 146 00:09:27,134 --> 00:09:30,661 creating a huge explosion, a supernova. 147 00:09:40,947 --> 00:09:46,351 But some stars are even bigger than that. 148 00:09:46,353 --> 00:09:51,382 These supermassive stars weigh 100 times more than our sun 149 00:09:51,391 --> 00:09:54,258 and have 100 times more gravity. 150 00:09:54,261 --> 00:09:56,662 When one of these stars dies, 151 00:09:56,663 --> 00:10:02,397 it sets off the biggest explosion in the universe... 152 00:10:02,402 --> 00:10:04,530 A hypernova. 153 00:10:14,414 --> 00:10:18,749 This is the birth of a black hole. 154 00:10:25,225 --> 00:10:30,163 Narrator: Our universe is full of stars. 155 00:10:30,163 --> 00:10:34,100 At the end of their lives, some die quietly. 156 00:10:34,101 --> 00:10:38,402 Others go out in spectacular explosions. 157 00:10:38,405 --> 00:10:43,866 And some give birth to black holes. 158 00:10:43,877 --> 00:10:45,811 Dr. Plait: If you have a star, 159 00:10:45,812 --> 00:10:49,112 a supermassive star that's 100 times the mass of the Sun, 160 00:10:49,116 --> 00:10:52,074 at the end of its life, the core runs out of fuel. 161 00:10:52,085 --> 00:10:53,985 There's nothing left to hold it up, 162 00:10:53,987 --> 00:10:56,513 and the core collapses down into a black hole. 163 00:10:56,523 --> 00:11:00,187 Narrator: When that happens, the enormous gravity 164 00:11:00,193 --> 00:11:05,256 generated at the heart of supermassive stars runs wild. 165 00:11:08,201 --> 00:11:13,139 This is the dying star V.Y. Canis Majoris. 166 00:11:13,140 --> 00:11:17,668 It's more than a billion miles across. 167 00:11:20,914 --> 00:11:25,351 Like all stars, it's a giant nuclear-fusion reactor, 168 00:11:25,352 --> 00:11:27,753 pumping energy outward. 169 00:11:27,754 --> 00:11:33,249 At the same time, the star's extreme gravity crushes inward. 170 00:11:33,260 --> 00:11:35,285 For a few million years, 171 00:11:35,295 --> 00:11:39,391 fusion and gravity are locked in standoff. 172 00:11:39,399 --> 00:11:42,460 But when the star runs out of fuel, 173 00:11:42,469 --> 00:11:46,372 fusion stops and the stalemate ends. 174 00:11:46,373 --> 00:11:48,102 Gravity wins. 175 00:11:51,144 --> 00:11:52,805 In a millisecond, 176 00:11:52,812 --> 00:11:56,146 the core shrinks to a fraction of its original size 177 00:11:56,149 --> 00:12:00,211 and a baby black hole is born. 178 00:12:00,220 --> 00:12:01,881 Immediately, 179 00:12:01,888 --> 00:12:05,791 it starts to cannibalize what's left of the star. 180 00:12:05,792 --> 00:12:09,228 As matter swirls into the black hole, it gets incredibly hot. 181 00:12:09,229 --> 00:12:11,755 And there are magnetic forces and frictional forces, 182 00:12:11,765 --> 00:12:13,859 and it's just a witch's brew, a nightmare, 183 00:12:13,867 --> 00:12:16,632 what's going on right above the surface of the black hole. 184 00:12:16,636 --> 00:12:19,298 Narrator: The new black hole in the middle 185 00:12:19,306 --> 00:12:22,264 keeps feeding on the body of the star around it. 186 00:12:22,275 --> 00:12:27,042 It eats the gas so fast, it chokes and coughs, 187 00:12:27,047 --> 00:12:30,210 blasting out huge beams of energy. 188 00:12:34,387 --> 00:12:37,584 Dr. Plait: They basically eat their way out from the star. 189 00:12:37,591 --> 00:12:39,423 This happens in milliseconds. 190 00:12:39,426 --> 00:12:42,259 It happens before the rest of the star even knows 191 00:12:42,262 --> 00:12:43,752 the core is gone. 192 00:12:43,763 --> 00:12:48,200 And so basically, the star is dead before it hits the ground. 193 00:12:51,871 --> 00:12:55,671 Narrator: Finally, the star explodes. 194 00:12:58,411 --> 00:13:03,679 In one second, it blasts out 100 times more energy 195 00:13:03,683 --> 00:13:07,881 than our sun will produce over its entire life. 196 00:13:10,357 --> 00:13:15,158 What's left is a new black hole and two jets of energy 197 00:13:15,161 --> 00:13:19,826 hurtling through the universe at the speed of light. 198 00:13:19,833 --> 00:13:23,463 These jets are called "gamma-ray bursts." 199 00:13:28,908 --> 00:13:32,037 Dr. Plait: They're incredibly energetic events. 200 00:13:32,045 --> 00:13:34,377 In terms of raw energy and power, 201 00:13:34,381 --> 00:13:37,612 gamma ray bursts are second only to the Big Bang itself. 202 00:13:39,252 --> 00:13:42,244 Narrator: Most of them last only a few seconds. 203 00:13:42,255 --> 00:13:45,691 And they fry anything in their way. 204 00:13:49,596 --> 00:13:52,964 They're so intense that if there was a gamma-ray burster 205 00:13:52,966 --> 00:13:55,992 in the region of our galaxy near our solar system, 206 00:13:56,002 --> 00:13:59,404 it could literally vaporize the entire planet. 207 00:13:59,406 --> 00:14:04,435 Narrator: Fortunately, most gamma-ray bursts occur outside our galaxy. 208 00:14:11,451 --> 00:14:14,421 But they tell us something important 209 00:14:14,421 --> 00:14:19,450 about black holes and how our universe works. 210 00:14:19,459 --> 00:14:22,827 What we were seeing every time a gamma-ray burst went off 211 00:14:22,829 --> 00:14:25,526 was basically the birth cry of a black hole. 212 00:14:25,532 --> 00:14:30,732 Narrator: By counting gamma-ray bursts, astronomers can figure out 213 00:14:30,737 --> 00:14:33,434 how many black holes are being created. 214 00:14:33,440 --> 00:14:37,707 In 2004, NASA launched the Swift probe 215 00:14:37,711 --> 00:14:41,170 to scan the universe for gamma-ray bursts. 216 00:14:41,181 --> 00:14:42,171 Man: Five... 217 00:14:42,182 --> 00:14:43,206 four... 218 00:14:43,216 --> 00:14:44,240 three... 219 00:14:44,250 --> 00:14:45,376 two... 220 00:14:45,385 --> 00:14:47,513 one... We have ignition. 221 00:14:47,520 --> 00:14:50,922 And we have lift-off of NASA's Swift spacecraft, 222 00:14:50,924 --> 00:14:54,224 on a mission to study and understand gamma-ray bursts 223 00:14:54,227 --> 00:14:55,695 throughout the universe. 224 00:15:02,102 --> 00:15:05,197 Narrator: This is the most powerful gamma-ray burst 225 00:15:05,205 --> 00:15:07,367 Swift has detected so far. 226 00:15:07,374 --> 00:15:11,333 The flash of light announces the birth of a new black hole 227 00:15:11,344 --> 00:15:13,813 on the other side of the universe. 228 00:15:18,084 --> 00:15:22,851 Swift can only look at a fraction of what's out there. 229 00:15:27,193 --> 00:15:31,994 Still, it detects at least one gamma-ray burst every day. 230 00:15:33,967 --> 00:15:38,564 That discovery rocked astronomy to its foundations. 231 00:15:41,007 --> 00:15:43,840 Dr. Kaku: We once thought that black holes, like unicorns, 232 00:15:43,843 --> 00:15:46,471 could never be found. 233 00:15:46,479 --> 00:15:49,881 We now believe that there are perhaps billions of black holes 234 00:15:49,883 --> 00:15:51,180 in the night sky. 235 00:15:51,184 --> 00:15:53,881 When we look around our galaxy and other galaxies, 236 00:15:53,887 --> 00:15:58,757 it's clear that the universe is full of powerful black holes. 237 00:15:58,758 --> 00:16:01,318 Narrator: Finding black holes is one thing. 238 00:16:01,327 --> 00:16:02,988 Figuring out how they work -- 239 00:16:02,996 --> 00:16:05,158 that's a whole different ball game. 240 00:16:05,165 --> 00:16:07,930 The only way to find out is to visit one. 241 00:16:07,934 --> 00:16:12,337 You'd have to take a spacecraft across the vastness of space 242 00:16:12,338 --> 00:16:14,170 just to get close to it. 243 00:16:14,174 --> 00:16:18,407 Then you'd have to go inside the black hole. 244 00:16:18,411 --> 00:16:20,311 There, you'd find a place 245 00:16:20,313 --> 00:16:24,443 where reality breaks down and time stands still. 246 00:16:28,121 --> 00:16:31,489 Narrator: There are billions of black holes in the universe. 247 00:16:31,491 --> 00:16:34,859 We can detect them with telescopes and satellites. 248 00:16:34,861 --> 00:16:39,526 But we don't actually know what they're like up-close. 249 00:16:39,532 --> 00:16:40,931 It's a long way off, 250 00:16:40,934 --> 00:16:43,562 but scientists are already speculating 251 00:16:43,570 --> 00:16:46,938 about a mission to a black hole... 252 00:16:46,940 --> 00:16:51,673 A one-way trip to the most dangerous place in the universe. 253 00:16:55,415 --> 00:16:56,905 Dr. Kaku: Originally, 254 00:16:56,916 --> 00:17:01,820 physicists were horrified at the idea of black holes. 255 00:17:01,821 --> 00:17:03,414 They wanted to banish them, 256 00:17:03,423 --> 00:17:06,154 because the laws of physics, as we know them, 257 00:17:06,159 --> 00:17:09,117 seem to break down at the instant of a black hole. 258 00:17:09,128 --> 00:17:10,687 Time stops. 259 00:17:12,131 --> 00:17:14,964 Gravity becomes infinite. 260 00:17:14,968 --> 00:17:18,393 This is a nightmare. 261 00:17:18,404 --> 00:17:21,772 Narrator: Obviously, we can't send humans anywhere near a black hole. 262 00:17:21,774 --> 00:17:24,505 But a robot? Well, sure. 263 00:17:24,511 --> 00:17:27,640 A robotic probe could transmit data back 264 00:17:27,647 --> 00:17:30,378 just before it goes over the edge. 265 00:17:30,383 --> 00:17:35,378 That edge of a black hole is called the "event horizon." 266 00:17:35,388 --> 00:17:37,584 It's the edge of time and space -- 267 00:17:37,590 --> 00:17:41,220 at least, in the universe we know. 268 00:17:41,227 --> 00:17:43,286 We call the event horizon "event horizon" 269 00:17:43,296 --> 00:17:44,354 quite simply because 270 00:17:44,364 --> 00:17:46,128 it separates space into two regions. 271 00:17:48,935 --> 00:17:50,403 It's not a physical surface. 272 00:17:50,403 --> 00:17:53,771 You might not even notice it if you were falling through it, 273 00:17:53,773 --> 00:17:57,038 but ultimately, once you're inside of it, you're doomed. 274 00:17:57,043 --> 00:17:59,239 Narrator: As you approach the event horizon, 275 00:17:59,245 --> 00:18:01,009 gravity gets stronger 276 00:18:01,014 --> 00:18:05,110 and very strange things start to happen. 277 00:18:05,118 --> 00:18:08,315 Dr. Plait: As you fall into a black hole feet-first, 278 00:18:08,321 --> 00:18:10,847 your feet are closer to the black hole. 279 00:18:10,857 --> 00:18:14,555 And so the gravity they feel is stronger. 280 00:18:14,561 --> 00:18:16,359 Your head is not quite as close, 281 00:18:16,362 --> 00:18:18,558 and so the gravity it feels is less. 282 00:18:18,565 --> 00:18:21,330 And basically, what happens is, you get stretched out. 283 00:18:21,334 --> 00:18:23,701 Your feet are being pulled much harder than your head, 284 00:18:23,703 --> 00:18:25,068 and you're like a piece of taffy 285 00:18:25,071 --> 00:18:26,800 being pulled between two strong people. 286 00:18:29,275 --> 00:18:31,403 As you get thinner and thinner and thinner, 287 00:18:31,411 --> 00:18:33,436 as you get closer and closer and closer, 288 00:18:33,446 --> 00:18:37,007 you're undergoing a process we call "spaghettification" 289 00:18:37,016 --> 00:18:40,987 because you're basically turned into a long, thin tube of pasta. 290 00:18:44,924 --> 00:18:48,451 Narrator: Gravity would stretch our robotic probe to the limit, 291 00:18:48,461 --> 00:18:50,156 then rip it apart. 292 00:18:58,805 --> 00:19:01,297 But imagine if the probe was strong enough 293 00:19:01,307 --> 00:19:03,742 to survive and keep going. 294 00:19:06,679 --> 00:19:12,118 As it gets close to the event horizon, everything goes crazy. 295 00:19:12,118 --> 00:19:17,682 Gravity is so extreme, it stops time. 296 00:19:17,690 --> 00:19:20,022 Dr. Kaku: We think of time as being endless. 297 00:19:20,026 --> 00:19:23,189 However, in a black hole, in some sense, time stops. 298 00:19:27,467 --> 00:19:30,493 Dr. Plait: This sounds like it's nuts, but that's the way it works. 299 00:19:30,503 --> 00:19:31,937 It's in the math. 300 00:19:31,938 --> 00:19:36,341 It's actually woven into the fabric of the universe itself. 301 00:19:36,342 --> 00:19:39,107 Narrator: If you were to watch from a distance, 302 00:19:39,112 --> 00:19:41,513 the robot probe would seem to slow down 303 00:19:41,514 --> 00:19:44,040 as it gets closer to the black hole. 304 00:19:44,050 --> 00:19:47,850 Then it would appear to stop completely. 305 00:19:47,854 --> 00:19:50,983 The whole process might just take a brief moment. 306 00:19:50,990 --> 00:19:52,389 But from the outside, 307 00:19:52,392 --> 00:19:56,590 you appear to freeze and fall ever more slowly. 308 00:19:56,596 --> 00:19:59,293 You actually can never observe an object fall 309 00:19:59,298 --> 00:20:01,665 all the way through the event horizon. 310 00:20:01,668 --> 00:20:04,103 It literally freezes at the surface 311 00:20:04,103 --> 00:20:07,266 because its clock is going infinitely slowly 312 00:20:07,273 --> 00:20:08,775 compared to yours. 313 00:20:08,775 --> 00:20:13,679 Narrator: In reality, the probe hasn't stopped at all. 314 00:20:13,680 --> 00:20:17,878 It keeps going and crosses the event horizon. 315 00:20:19,786 --> 00:20:22,744 If the probe points its cameras backwards, 316 00:20:22,755 --> 00:20:25,224 towards the entrance of the black hole, 317 00:20:25,224 --> 00:20:30,890 it will see light being sucked in. 318 00:20:30,897 --> 00:20:35,960 If it points the camera forward, at first it sees only black, 319 00:20:35,968 --> 00:20:39,370 but as it moves toward the heart of the black hole, 320 00:20:39,372 --> 00:20:44,139 it encounters the most bizarre place in the universe. 321 00:20:45,778 --> 00:20:49,772 The black hole's immense gravity pulls everything down 322 00:20:49,782 --> 00:20:53,184 to an unimaginably small point at its center. 323 00:20:53,186 --> 00:20:57,783 Scientists call it the "singularity." 324 00:20:57,790 --> 00:21:00,282 We really just don't know 325 00:21:00,293 --> 00:21:02,557 what happens at the center of a black hole. 326 00:21:02,562 --> 00:21:03,859 The densities are so great 327 00:21:03,863 --> 00:21:06,457 that the laws of physics break down, as we know them. 328 00:21:06,466 --> 00:21:11,233 A singularity is a point of infinite gravity, 329 00:21:11,237 --> 00:21:14,434 where space and time become meaningless. 330 00:21:14,440 --> 00:21:16,340 Now, that is ridiculous. 331 00:21:16,342 --> 00:21:21,212 A singularity is basically a word for saying "I don't know." 332 00:21:21,214 --> 00:21:23,478 It's a word for saying "I'm clueless." 333 00:21:27,754 --> 00:21:28,949 Narrator: Even now, 334 00:21:28,955 --> 00:21:31,515 scientists can't really answer the question, 335 00:21:31,524 --> 00:21:32,889 "What is a black hole?" 336 00:21:32,892 --> 00:21:34,485 Dr. Plait: It's upsetting, a little bit, 337 00:21:34,494 --> 00:21:36,087 to think that there are objects out there 338 00:21:36,095 --> 00:21:38,496 that are breaking the laws of physics. 339 00:21:38,498 --> 00:21:40,899 There must be bigger laws 340 00:21:40,900 --> 00:21:42,800 that are being used by these black holes, 341 00:21:42,802 --> 00:21:44,736 that are being obeyed by these black holes, 342 00:21:44,737 --> 00:21:46,296 that we just don't understand yet. 343 00:21:49,809 --> 00:21:52,972 Narrator: Okay, so, the one thing we do understand 344 00:21:52,979 --> 00:21:56,404 is that black holes are born from dying stars. 345 00:21:58,551 --> 00:22:02,010 And most are small -- around 20 miles across. 346 00:22:05,358 --> 00:22:08,384 But now scientists have discovered 347 00:22:08,394 --> 00:22:11,694 that some black holes are much bigger. 348 00:22:11,697 --> 00:22:14,894 They're called "supermassive black holes." 349 00:22:14,901 --> 00:22:19,236 They're the same size as our entire solar system. 350 00:22:19,238 --> 00:22:24,733 And one of these monsters lies at the heart of our own galaxy. 351 00:22:29,282 --> 00:22:33,708 Narrator: Our solar system lies in the Milky Way galaxy. 352 00:22:33,719 --> 00:22:38,316 It's made up of billions of stars, including our sun... 353 00:22:40,626 --> 00:22:43,755 ...all revolving around a mysterious region 354 00:22:43,763 --> 00:22:46,425 right at the center. 355 00:22:46,432 --> 00:22:49,732 Dr. Kaku: Children ask the question -- 356 00:22:49,735 --> 00:22:51,430 if the Moon goes around the Earth, 357 00:22:51,437 --> 00:22:52,802 the Earth goes around the Sun, 358 00:22:52,805 --> 00:22:54,534 then what does the Sun go around? 359 00:22:54,540 --> 00:22:56,008 Narrator: It's a good question. 360 00:22:56,008 --> 00:22:58,375 And astronomers ask the same thing. 361 00:22:58,377 --> 00:23:00,402 Maybe there was something going on 362 00:23:00,413 --> 00:23:02,245 at the heart of the Milky Way -- 363 00:23:02,248 --> 00:23:07,687 perhaps a black hole at the very center. 364 00:23:07,687 --> 00:23:11,817 But because we can't actually see a black hole, 365 00:23:11,824 --> 00:23:16,990 the best they could do was look for telltale signs. 366 00:23:16,996 --> 00:23:18,725 Using infrared telescopes, 367 00:23:18,731 --> 00:23:21,428 they looked at the middle of the galaxy 368 00:23:21,434 --> 00:23:24,802 and discovered a densely packed swarm 369 00:23:24,804 --> 00:23:26,704 of millions of stars. 370 00:23:26,706 --> 00:23:30,574 But they couldn't see what was at the center. 371 00:23:35,748 --> 00:23:40,242 One team has spent 15 years looking for clues. 372 00:23:44,924 --> 00:23:48,224 High above the clouds on Mauna Kea, in Hawaii, 373 00:23:48,227 --> 00:23:51,595 the giant Keck telescope has the power 374 00:23:51,597 --> 00:23:56,034 to see right through to the center of the Milky Way. 375 00:24:02,808 --> 00:24:05,505 The region which we have to study 376 00:24:05,511 --> 00:24:08,879 to prove that there's a black hole is incredibly small. 377 00:24:08,881 --> 00:24:10,542 It is absolutely the case 378 00:24:10,549 --> 00:24:13,143 of looking for a needle in a haystack, 379 00:24:13,152 --> 00:24:15,985 except we know exactly where the needle is. 380 00:24:17,857 --> 00:24:20,986 Narrator: Andrea Ghez has spent countless nights 381 00:24:20,993 --> 00:24:23,325 scanning the center of the galaxy 382 00:24:23,329 --> 00:24:25,730 for signs of a black hole. 383 00:24:25,731 --> 00:24:27,597 To be able to do this experiment, 384 00:24:27,600 --> 00:24:29,034 one has to be able to see 385 00:24:29,035 --> 00:24:31,868 the stars that are very close to the center of the galaxy 386 00:24:31,871 --> 00:24:34,704 and to position them incredibly accurately. 387 00:24:34,707 --> 00:24:36,505 And this would be equivalent 388 00:24:36,509 --> 00:24:39,570 to me in Los Angeles looking at you in New York 389 00:24:39,578 --> 00:24:43,640 and seeing you be able to move your finger like this. 390 00:24:47,486 --> 00:24:49,750 [motors whirring] 391 00:24:57,496 --> 00:24:59,430 Narrator: As the Keck kicks into action, 392 00:24:59,432 --> 00:25:03,528 a laser beam detects tiny disturbances in the atmosphere 393 00:25:03,536 --> 00:25:05,903 that would distort the image. 394 00:25:08,641 --> 00:25:14,569 Motors then adjust the huge 30-foot mirror to compensate. 395 00:25:14,580 --> 00:25:16,810 The image is clear enough 396 00:25:16,816 --> 00:25:20,844 to track the stars at the heart of our galaxy. 397 00:25:23,189 --> 00:25:27,717 Ghez has taken thousands of images over the last 15 years. 398 00:25:27,727 --> 00:25:33,325 And what they reveal is amazing. 399 00:25:33,332 --> 00:25:36,063 The stars at the center of the galaxy 400 00:25:36,068 --> 00:25:38,935 are moving at millions of miles an hour. 401 00:25:45,411 --> 00:25:49,848 The center of the galaxy is a very extreme environment. 402 00:25:49,849 --> 00:25:51,806 The speeds with which stars move 403 00:25:51,817 --> 00:25:54,843 is much higher than anywhere else in our galaxy. 404 00:25:54,854 --> 00:25:57,619 And that is absolutely the signpost of the black hole. 405 00:26:02,962 --> 00:26:08,867 Narrator: They look like tiny planets racing around an invisible sun. 406 00:26:08,868 --> 00:26:12,395 But they're not planets. They're stars. 407 00:26:12,405 --> 00:26:14,464 It takes a lot of gravity 408 00:26:14,473 --> 00:26:18,808 to swing huge stars around in such fast, tight orbits. 409 00:26:18,811 --> 00:26:23,840 There's only one thing in the universe with that much pull... 410 00:26:23,849 --> 00:26:28,912 a supermassive black hole. 411 00:26:28,921 --> 00:26:31,185 Watching these things shows the presence 412 00:26:31,190 --> 00:26:34,057 of a 4-million-times- the-mass-of-our-sun black hole, 413 00:26:34,060 --> 00:26:36,324 located right at the heart of our galaxy. 414 00:26:37,997 --> 00:26:40,227 Narrator: It is a huge discovery. 415 00:26:40,232 --> 00:26:44,066 Everything in our galaxy, including our own solar system, 416 00:26:44,070 --> 00:26:48,803 orbits around a supermassive black hole. 417 00:26:48,808 --> 00:26:51,903 But the Milky Way isn't the only galaxy 418 00:26:51,911 --> 00:26:54,278 with a black hole in the middle. 419 00:26:54,280 --> 00:26:56,510 There are supermassive black holes 420 00:26:56,515 --> 00:26:59,974 at the heart of most galaxies in the universe. 421 00:26:59,985 --> 00:27:03,546 The Andromeda galaxy is our closest neighbor. 422 00:27:03,556 --> 00:27:07,049 It circles around a supermassive black hole 423 00:27:07,059 --> 00:27:11,826 weighing 140 million times more than our sun. 424 00:27:11,831 --> 00:27:15,256 Other galaxies, like this one, M87, 425 00:27:15,267 --> 00:27:21,263 have black holes weighing as much as 20 billion suns. 426 00:27:21,273 --> 00:27:23,901 How do black holes get so big, 427 00:27:23,909 --> 00:27:28,346 and what are they doing at the center of galaxies? 428 00:27:28,347 --> 00:27:33,808 For answers, we have to go back nearly 14 billion years 429 00:27:33,819 --> 00:27:37,813 to the beginning of the universe. 430 00:27:37,823 --> 00:27:39,552 Back then, 431 00:27:39,558 --> 00:27:44,189 the universe was filled with clouds of gas from the Big Bang. 432 00:27:44,196 --> 00:27:45,789 In some places, 433 00:27:45,798 --> 00:27:49,632 the gas was thick enough for millions of stars to form. 434 00:27:54,540 --> 00:27:57,771 Most of these new stars were supermassive. 435 00:27:57,776 --> 00:27:59,835 They burned hot and fast 436 00:27:59,845 --> 00:28:03,873 and then exploded, creating lots of black holes. 437 00:28:14,460 --> 00:28:17,293 The early universe was a wild-and-crazy place 438 00:28:17,296 --> 00:28:19,560 where huge regions of mass 439 00:28:19,565 --> 00:28:20,930 were collapsing catastrophically, 440 00:28:20,933 --> 00:28:22,264 producing black holes. 441 00:28:22,268 --> 00:28:25,033 And, in fact, the early universe might have been 442 00:28:25,037 --> 00:28:27,404 full of emerging black holes everywhere. 443 00:28:30,109 --> 00:28:32,874 Narrator: Gravity pulled many of them together. 444 00:28:32,878 --> 00:28:35,210 All over the early universe, 445 00:28:35,214 --> 00:28:39,412 they merged, creating larger and larger black holes. 446 00:28:42,421 --> 00:28:46,221 Over hundreds of millions of years, each black hole grew, 447 00:28:46,225 --> 00:28:50,662 producing stronger gravity and pulling in more and more gas. 448 00:28:50,663 --> 00:28:55,260 New stars were born from the gas, forming primitive galaxies. 449 00:28:57,336 --> 00:29:01,204 But the black hole kept on sucking in gas, 450 00:29:01,207 --> 00:29:03,073 until it could take no more, 451 00:29:03,075 --> 00:29:07,137 igniting the most powerful flamethrower in the universe. 452 00:29:21,160 --> 00:29:24,596 Narrator: A young galaxy is a vast cluster of stars, 453 00:29:24,597 --> 00:29:27,623 stars that formed from clouds of gas. 454 00:29:32,571 --> 00:29:35,097 At the center of the new galaxy 455 00:29:35,107 --> 00:29:39,567 is a young, supermassive black hole feeding on the gas, 456 00:29:39,578 --> 00:29:41,569 getting bigger and bigger. 457 00:29:41,580 --> 00:29:42,843 Dr. Plait: If you can imagine, 458 00:29:42,848 --> 00:29:45,783 when a galaxy is very young and still forming, 459 00:29:45,784 --> 00:29:48,617 there's a supermassive black hole forming at the core, 460 00:29:48,621 --> 00:29:50,612 and the gas is still falling into it 461 00:29:50,623 --> 00:29:52,148 and still forming the galaxy. 462 00:29:52,157 --> 00:29:54,524 Well, near that central black hole, 463 00:29:54,526 --> 00:29:56,221 things are getting very hot. 464 00:29:56,228 --> 00:29:57,923 That material is heating up. 465 00:29:57,930 --> 00:30:01,560 Narrator: Gas is speeding into the black hole. 466 00:30:01,567 --> 00:30:04,059 But it overloads, 467 00:30:04,069 --> 00:30:08,802 and there is no room for all that excess hot gas. 468 00:30:08,807 --> 00:30:13,210 It has nowhere to go but out. 469 00:30:13,212 --> 00:30:18,275 It's blasted into space in huge jets of energy. 470 00:30:22,921 --> 00:30:26,448 Each jet is 20 times wider than our solar system 471 00:30:26,458 --> 00:30:30,691 and shoots clear through the galaxy. 472 00:30:30,696 --> 00:30:36,658 The supermassive black hole has ignited a quasar. 473 00:30:36,669 --> 00:30:38,433 Quasars are literally 474 00:30:38,437 --> 00:30:40,599 the brightest objects in the universe. 475 00:30:40,606 --> 00:30:43,667 They're so intense, they can outshine an entire galaxy. 476 00:30:43,676 --> 00:30:46,509 Narrator: This is a real photograph 477 00:30:46,512 --> 00:30:50,380 of a real quasar in the galaxy M87, 478 00:30:50,382 --> 00:30:53,977 50 million light-years away. 479 00:30:57,456 --> 00:31:01,120 Quasars blast away huge quantities of gas 480 00:31:01,126 --> 00:31:03,060 from the surrounding galaxy... 481 00:31:05,764 --> 00:31:10,292 ...the equivalent of 10 Earths every minute. 482 00:31:13,739 --> 00:31:15,935 Dr. Plait: When you heat up a gas, 483 00:31:15,941 --> 00:31:18,103 it tends to expand and it blows outward. 484 00:31:18,110 --> 00:31:20,807 And it's sort of like a wind, but on a huge scale. 485 00:31:20,813 --> 00:31:22,838 And you get a black-hole wind, 486 00:31:22,848 --> 00:31:25,442 gas blowing out from the black hole. 487 00:31:25,451 --> 00:31:30,218 Narrator: Black holes suck gas in. Quasars blow it out. 488 00:31:30,222 --> 00:31:34,853 But eventually there's no gas left to make stars, 489 00:31:34,860 --> 00:31:36,624 and the galaxy stops growing. 490 00:31:36,628 --> 00:31:39,427 Dr. Plait: So we think that the eventual size 491 00:31:39,431 --> 00:31:40,990 that a galaxy can achieve 492 00:31:40,999 --> 00:31:43,559 depends on the black hole in its center. 493 00:31:43,569 --> 00:31:45,094 The two are tied together. 494 00:31:47,072 --> 00:31:51,873 Narrator: With no gas left to feed on, the quasar jets shrink and die. 495 00:31:53,345 --> 00:31:56,440 What's left is a supermassive black hole 496 00:31:56,448 --> 00:32:00,851 at the center of the galaxy, with a whole lot of young stars, 497 00:32:00,853 --> 00:32:04,915 just like our Milky Way back when it was young. 498 00:32:04,923 --> 00:32:07,654 Dr. Plait: Early on in the history of the Milky Way, 499 00:32:07,659 --> 00:32:11,061 when it was a young galaxy, we were probably a quasar. 500 00:32:11,063 --> 00:32:14,556 Probably every big galaxy was a quasar when it was young. 501 00:32:14,566 --> 00:32:16,125 But right now we're old enough 502 00:32:16,135 --> 00:32:18,092 that the galaxy has quieted down. 503 00:32:19,872 --> 00:32:23,809 Narrator: Now astronomers are looking for quasars, 504 00:32:23,809 --> 00:32:27,211 the secret to finding more black holes 505 00:32:27,212 --> 00:32:29,840 and figuring out how they work. 506 00:32:29,848 --> 00:32:33,284 The Chandra observatory is a space telescope 507 00:32:33,285 --> 00:32:39,054 that can detect the powerful x-rays quasars send out. 508 00:32:39,057 --> 00:32:41,958 It's found thousands. 509 00:32:41,960 --> 00:32:44,486 These remarkable images show 510 00:32:44,496 --> 00:32:49,400 quasars of all shapes and sizes firing out into space. 511 00:32:53,472 --> 00:32:55,668 Each one is a signpost 512 00:32:55,674 --> 00:32:59,702 for a young galaxy with a new black hole at its center. 513 00:33:03,549 --> 00:33:06,610 These quasars will eventually calm down 514 00:33:06,618 --> 00:33:11,954 as their galaxy matures and takes its final shape. 515 00:33:11,957 --> 00:33:13,891 I guess the universe is a lot like people -- 516 00:33:13,892 --> 00:33:15,326 active when they're young, 517 00:33:15,327 --> 00:33:17,659 a little bit quieter and more relaxed when they get older. 518 00:33:19,865 --> 00:33:22,891 Narrator: We now know that supermassive black holes 519 00:33:22,901 --> 00:33:26,963 and the quasars they create control galaxies. 520 00:33:26,972 --> 00:33:31,000 Dr. Ghez: Black holes are central to understanding how galaxies form. 521 00:33:31,009 --> 00:33:34,035 They're a key to understanding how they evolve with time. 522 00:33:34,046 --> 00:33:36,447 So, in fact, rather than being obscura, 523 00:33:36,448 --> 00:33:38,507 they're fundamental to our understanding 524 00:33:38,517 --> 00:33:40,315 of our galaxies and our universe. 525 00:33:40,319 --> 00:33:44,586 Narrator: The only way to find out more about black holes 526 00:33:44,590 --> 00:33:46,615 is to get a good look at one. 527 00:33:46,625 --> 00:33:50,425 And since an up-close visit is, well, not a good idea, 528 00:33:50,429 --> 00:33:53,387 astronomers are trying to devise a way to take a picture 529 00:33:53,398 --> 00:33:57,266 of the supermassive black hole at the heart of our own galaxy. 530 00:33:57,269 --> 00:33:58,759 To get it, 531 00:33:58,770 --> 00:34:02,900 they'll need a telescope as large as Earth itself. 532 00:34:13,852 --> 00:34:16,981 [high-pitched whir] 533 00:34:16,989 --> 00:34:18,980 Narrator: There's a supermassive black hole 534 00:34:18,991 --> 00:34:22,484 at the center of the Milky Way. 535 00:34:24,830 --> 00:34:27,788 It's hidden by a dense cluster of stars 536 00:34:27,799 --> 00:34:30,291 circling the heart of the galaxy. 537 00:34:33,138 --> 00:34:37,632 But soon, we hope we'll be able to see it. 538 00:34:37,643 --> 00:34:41,068 Dr. Kaku: Seeing is believing. 539 00:34:41,079 --> 00:34:44,310 It would be spectacular if we can go right up there, 540 00:34:44,316 --> 00:34:47,217 nose-to-nose with the event horizon 541 00:34:47,219 --> 00:34:50,621 of the black hole at the center of the Milky Way galaxy. 542 00:34:50,622 --> 00:34:53,922 And that's the Holy Grail. 543 00:34:53,926 --> 00:34:57,226 Narrator: A supermassive black hole lies hidden 544 00:34:57,229 --> 00:34:59,323 at the center of most galaxies. 545 00:34:59,331 --> 00:35:01,129 We only know they're there 546 00:35:01,133 --> 00:35:04,091 because the stars around them are drawn in 547 00:35:04,102 --> 00:35:06,332 at millions of miles per hour. 548 00:35:06,338 --> 00:35:08,033 But there might still be a way 549 00:35:08,040 --> 00:35:11,601 to take a picture of the very edge of the black hole -- 550 00:35:11,610 --> 00:35:13,840 the event horizon. 551 00:35:13,845 --> 00:35:17,645 Shep Doeleman and his team are trying to capture an image 552 00:35:17,649 --> 00:35:19,708 that shows its outline. 553 00:35:19,718 --> 00:35:21,982 We're essentially looking for the shadow, 554 00:35:21,987 --> 00:35:24,046 or the silhouette, of the black hole, 555 00:35:24,056 --> 00:35:27,549 within this cloud of gas that's swirling around it. 556 00:35:27,559 --> 00:35:31,291 This technique that we're exploiting 557 00:35:31,296 --> 00:35:34,322 is the best hope I think we have 558 00:35:34,333 --> 00:35:37,132 to actually image a region of the universe 559 00:35:37,135 --> 00:35:40,537 which has hitherto been completely invisible to us. 560 00:35:40,539 --> 00:35:42,837 Narrator: Optical telescopes 561 00:35:42,841 --> 00:35:46,368 can't see the black hole directly. 562 00:35:46,378 --> 00:35:50,246 But the glowing, super-heated gas surrounding the black hole 563 00:35:50,248 --> 00:35:53,718 sends out radio waves that can be used to make an image. 564 00:35:55,787 --> 00:36:01,123 Huge radio telescopes pick up these signals from space. 565 00:36:01,126 --> 00:36:03,618 The antenna will move in azimuth and elevation. 566 00:36:03,629 --> 00:36:05,961 [beeping] 567 00:36:05,964 --> 00:36:08,433 [whirring] 568 00:36:10,202 --> 00:36:13,968 Narrator: This one, at the M.l.T. Observatory near Boston, 569 00:36:13,972 --> 00:36:16,703 is more than 100 feet wide. 570 00:36:16,708 --> 00:36:20,838 It's big enough to detect very faint radio emissions 571 00:36:20,846 --> 00:36:25,807 from the black hole in our own galaxy, 25,000 light-years away. 572 00:36:25,817 --> 00:36:30,118 But it's not nearly big enough to capture an image. 573 00:36:30,122 --> 00:36:33,649 We need to take multiple copies of these telescopes, 574 00:36:33,659 --> 00:36:35,525 place them around the world 575 00:36:35,527 --> 00:36:40,124 to create a virtual telescope as large as the Earth itself. 576 00:36:40,132 --> 00:36:43,090 Narrator: Doeleman's team will link up radio telescopes 577 00:36:43,101 --> 00:36:47,265 around the globe, from Hawaii to Chile to Africa. 578 00:36:53,478 --> 00:36:56,140 When the whole network is connected, 579 00:36:56,148 --> 00:37:00,244 they'll have a virtual dish over 10,000 miles across, 580 00:37:00,252 --> 00:37:04,814 with 500 times the power of a single telescope. 581 00:37:08,260 --> 00:37:10,820 They think it will be powerful enough 582 00:37:10,829 --> 00:37:13,457 to take a picture of the event horizon 583 00:37:13,465 --> 00:37:18,960 of the supermassive black hole at the center of the Milky Way. 584 00:37:18,970 --> 00:37:21,439 They're already picking up signals 585 00:37:21,440 --> 00:37:23,966 from the dark heart of our galaxy. 586 00:37:23,975 --> 00:37:26,535 Dr. Doeleman: When we saw the first detection, 587 00:37:26,545 --> 00:37:29,276 it was a moment where I just looked at the computer screen 588 00:37:29,281 --> 00:37:32,046 and said to myself, "My God, we've done it. 589 00:37:32,050 --> 00:37:34,985 We've actually seen something that's so small 590 00:37:34,986 --> 00:37:37,478 that it has to be coming from right around the event horizon." 591 00:37:39,057 --> 00:37:42,584 Narrator: The signals are still too weak to give a complete picture, 592 00:37:42,594 --> 00:37:46,292 but Doeleman expects the images to improve 593 00:37:46,298 --> 00:37:51,259 as more telescopes come online over the next few years. 594 00:37:51,269 --> 00:37:56,503 Eventually, the outline of the black hole itself should emerge. 595 00:37:59,144 --> 00:38:04,310 But even a picture can't compare to witnessing it for yourself. 596 00:38:06,618 --> 00:38:10,020 In the distant future, we may have the technology 597 00:38:10,021 --> 00:38:14,492 to actually enter and pass through a black hole 598 00:38:14,493 --> 00:38:17,554 and maybe even survive the journey. 599 00:38:23,168 --> 00:38:26,536 Then we might finally answer the question -- 600 00:38:26,538 --> 00:38:30,509 what lies at the heart of a black hole? 601 00:38:32,677 --> 00:38:34,111 Some scientists believe 602 00:38:34,112 --> 00:38:36,877 we could use black holes as a kind of portal, 603 00:38:36,882 --> 00:38:40,182 with the potential for travel across the universe. 604 00:38:40,185 --> 00:38:42,984 Dr. Kaku: This is still very speculative, 605 00:38:42,988 --> 00:38:45,480 but the mathematics seem to indicate 606 00:38:45,490 --> 00:38:47,822 that as you fall through a black hole 607 00:38:47,826 --> 00:38:49,487 that you don't simply die -- 608 00:38:49,494 --> 00:38:52,191 you fall right through a wormhole, 609 00:38:52,197 --> 00:38:56,896 which is a gateway, a shortcut through space and time. 610 00:38:56,902 --> 00:39:00,566 Perhaps we could simply rocket across the universe 611 00:39:00,572 --> 00:39:05,908 through a subway system that we call a black hole. 612 00:39:05,911 --> 00:39:10,212 Narrator: If black holes are shortcuts through space and time, 613 00:39:10,215 --> 00:39:14,243 it could turn one of the coolest ideas from science fiction 614 00:39:14,252 --> 00:39:17,984 into reality. 615 00:39:17,989 --> 00:39:21,550 Time travel is possible, but not very practical. 616 00:39:21,560 --> 00:39:25,121 You see, the energy source, the material that you need 617 00:39:25,130 --> 00:39:27,656 to keep the throat of a wormhole open 618 00:39:27,666 --> 00:39:29,134 is something so exotic 619 00:39:29,134 --> 00:39:32,035 that we cannot produce it in the laboratory. 620 00:39:32,037 --> 00:39:34,995 But if you could, it might be possible 621 00:39:35,006 --> 00:39:39,136 to exploit the power of black holes to visit yesterday. 622 00:39:40,779 --> 00:39:43,544 Perhaps our descendants in the future 623 00:39:43,548 --> 00:39:46,381 have already mastered this technology. 624 00:39:46,384 --> 00:39:48,580 So one day, if somebody knocks on your door 625 00:39:48,587 --> 00:39:49,986 and claims to be 626 00:39:49,988 --> 00:39:52,423 your great-great-great-great- great-great granddaughter, 627 00:39:52,424 --> 00:39:53,414 don't slam the door. 628 00:39:57,462 --> 00:40:01,831 Narrator: Black holes might even be gateways to other universes. 629 00:40:01,833 --> 00:40:04,393 On the other side of a black hole, 630 00:40:04,402 --> 00:40:07,394 there could even be... a Big Bang. 631 00:40:10,709 --> 00:40:14,373 As a black hole collapses and matter falls into it, 632 00:40:14,379 --> 00:40:17,838 perhaps the matter is blown out the other side in a white hole. 633 00:40:17,849 --> 00:40:20,011 Doesn't that sound like the Big Bang? 634 00:40:25,690 --> 00:40:29,354 Narrator: if a Big Bang is just the flip side of a black hole, 635 00:40:29,361 --> 00:40:33,355 this could be how our own universe was born. 636 00:40:35,166 --> 00:40:37,692 If you look at the equations for a black hole 637 00:40:37,702 --> 00:40:39,602 and put in the parameters of the universe -- 638 00:40:39,604 --> 00:40:41,834 the mass of the universe, the size of the universe -- 639 00:40:41,840 --> 00:40:42,898 bingo! 640 00:40:42,908 --> 00:40:44,342 You find that our universe 641 00:40:44,342 --> 00:40:46,970 actually solves the equations for a black hole. 642 00:40:46,978 --> 00:40:50,209 In other words, we could be inside an event horizon. 643 00:40:50,215 --> 00:40:55,710 Perhaps we are actually living inside a black hole. 644 00:40:55,720 --> 00:40:59,179 Narrator: Every black hole might be the origin 645 00:40:59,190 --> 00:41:02,057 of an entirely separate universe. 646 00:41:02,060 --> 00:41:03,425 If that's true, 647 00:41:03,428 --> 00:41:08,025 there could be billions of universes out there... 648 00:41:11,503 --> 00:41:16,771 ...each one full of stars, planets, life. 649 00:41:16,775 --> 00:41:19,301 Whatever we figure out later, 650 00:41:19,311 --> 00:41:23,270 we know now that black holes are everywhere. 651 00:41:23,281 --> 00:41:24,510 They're bigger in size 652 00:41:24,516 --> 00:41:27,247 and more critical to the evolution of the universe 653 00:41:27,252 --> 00:41:29,380 than we ever imagined. 654 00:41:40,765 --> 00:41:42,699 Dr. Krauss: Literally, our understanding 655 00:41:42,701 --> 00:41:44,760 of the universe that's important around us, 656 00:41:44,769 --> 00:41:47,170 the universe that's visible to telescopes, 657 00:41:47,172 --> 00:41:49,038 has been profoundly affected 658 00:41:49,040 --> 00:41:52,408 by our realization that black holes are everywhere. 659 00:41:55,380 --> 00:41:56,643 Dr. Kaku: Once upon a time, 660 00:41:56,648 --> 00:41:58,309 people thought that black-hole physics 661 00:41:58,316 --> 00:42:01,479 was too fantastic to be true. 662 00:42:01,486 --> 00:42:04,114 And now they are center-stage. 663 00:42:04,122 --> 00:42:05,590 We now know they dominate 664 00:42:05,590 --> 00:42:07,786 the evolution of the universe itself. 665 00:42:09,761 --> 00:42:11,126 Dr. Plait: When I was a kid, 666 00:42:11,129 --> 00:42:13,427 black holes basically played a part in science fiction. 667 00:42:13,431 --> 00:42:14,956 It was always something to avoid. 668 00:42:14,966 --> 00:42:16,195 Your spaceship -- 669 00:42:16,201 --> 00:42:18,158 you try to get around them before you get drawn in. 670 00:42:18,169 --> 00:42:20,228 But what we've learned since then 671 00:42:20,238 --> 00:42:22,468 is that black holes play a huge role 672 00:42:22,474 --> 00:42:24,966 and a huge number of roles in the universe. 673 00:42:27,912 --> 00:42:30,244 It's not an exaggeration to say 674 00:42:30,248 --> 00:42:34,014 that if black holes did not exist, we wouldn't be here. 675 00:42:34,019 --> 00:42:36,750 We literally owe our existence to black holes. 676 00:42:40,925 --> 00:42:44,361 Narrator: The story's not over yet. 677 00:42:44,362 --> 00:42:46,990 There's still much more to be discovered 678 00:42:46,998 --> 00:42:51,936 about the mysterious objects called black holes... 679 00:42:51,936 --> 00:42:55,133 The masters of the universe. 55302

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