1 00:00:03,612 --> 00:00:08,834 ♪ ♪ 2 00:00:17,713 --> 00:00:21,325 [wind] 3 00:00:23,675 --> 00:00:26,200 SAGAN: We were hunters and foragers. 4 00:00:26,983 --> 00:00:29,768 The frontier was everywhere. 5 00:00:38,081 --> 00:00:42,999 We were bounded only by the earth and the ocean and the sky. 6 00:00:50,572 --> 00:00:54,967 The open road still softly calls like a nearly forgotten 7 00:00:55,142 --> 00:00:57,187 song of childhood. 8 00:00:58,188 --> 00:01:01,583 For all our failings, despite our limitations and 9 00:01:01,757 --> 00:01:05,674 fallibilities, we humans are capable of greatness. 10 00:01:11,549 --> 00:01:15,423 How far will our nomadic species have wandered by the 11 00:01:15,597 --> 00:01:18,121 end of the next century? 12 00:01:19,949 --> 00:01:22,734 And the next millennium? 13 00:01:42,189 --> 00:01:48,369 ♪ ♪ 14 00:01:50,022 --> 00:01:53,678 TYSON: Welcome back to the shores of the cosmic ocean... 15 00:01:54,026 --> 00:01:55,985 An immensity of space and time, 16 00:01:57,160 --> 00:01:59,597 a vastness still mostly uncharted. 17 00:02:00,468 --> 00:02:04,080 We're bound for the possible worlds revealed by science. 18 00:02:04,907 --> 00:02:08,258 We'll take a ride on the underground worldwide network 19 00:02:08,432 --> 00:02:10,173 that no one knew was there. 20 00:02:11,087 --> 00:02:14,221 I'm going to tell you a first contact story that's true. 21 00:02:17,267 --> 00:02:20,140 We'll meet some of the most courageous people who ever lived. 22 00:02:21,489 --> 00:02:26,363 And we're going to venture into the future we can still have, 23 00:02:26,885 --> 00:02:31,194 to the homes of our distant descendants among the stars. 24 00:02:31,934 --> 00:02:35,024 Science can carry us across that vastness. 25 00:02:35,198 --> 00:02:37,853 But without imagination, we go nowhere. 26 00:02:40,116 --> 00:02:43,467 Our Ship of the Imagination is propelled by twin engines 27 00:02:43,641 --> 00:02:45,861 of skepticism and wonder. 28 00:02:46,470 --> 00:02:50,605 It's guided by the simple set of rules that define science 29 00:02:50,779 --> 00:02:52,041 and make it so powerful. 30 00:02:53,695 --> 00:02:55,131 [splash] 31 00:02:55,697 --> 00:02:58,700 Test ideas by experiment and observation. 32 00:02:58,874 --> 00:03:01,485 Build on those ideas that pass the test. 33 00:03:02,138 --> 00:03:04,271 Reject the ones that fail. 34 00:03:04,445 --> 00:03:07,187 Follow the evidence wherever it leads. 35 00:03:07,361 --> 00:03:09,493 and question everything. 36 00:03:10,364 --> 00:03:14,716 Take these rules to heart, and the cosmos is yours. 37 00:03:15,717 --> 00:03:17,936 Come with me... 38 00:03:25,683 --> 00:03:31,472 [theme music plays]. 39 00:03:50,969 --> 00:03:56,671 ♪ ♪ 40 00:04:15,864 --> 00:04:22,262 ♪ ♪ 41 00:04:41,629 --> 00:04:47,504 ♪ ♪ 42 00:04:49,593 --> 00:04:52,335 TYSON: Our Ship of the Imagination can take us 43 00:04:52,509 --> 00:04:55,425 anywhere in space and time. 44 00:04:56,948 --> 00:04:59,995 The cosmos is right outside our front window. 45 00:05:01,257 --> 00:05:04,478 If you want to see the past, look down. 46 00:05:17,273 --> 00:05:20,320 And if you want to see the future, look up. 47 00:05:34,029 --> 00:05:37,815 On this voyage, we are bound for a distant galaxy. 48 00:05:39,904 --> 00:05:43,343 And we'll discover how we as a species became 49 00:05:43,517 --> 00:05:45,736 explorers of the cosmos. 50 00:05:46,520 --> 00:05:48,826 There. There she is. 51 00:05:49,000 --> 00:05:51,089 NASA's Voyager 1. 52 00:05:51,263 --> 00:05:53,440 Launched in 1977, 53 00:05:53,614 --> 00:05:56,312 she is the most distant object built by human hands. 54 00:05:57,792 --> 00:06:00,272 She's done some hard traveling since our last encounter, 55 00:06:00,925 --> 00:06:03,275 logged another billion and a half miles. 56 00:06:03,841 --> 00:06:07,149 Voyager's making for other parts of our Milky Way, 57 00:06:07,323 --> 00:06:10,587 but we have another, far more distant destination. 58 00:06:11,806 --> 00:06:15,113 The cosmic ocean is made of space and time. 59 00:06:15,897 --> 00:06:18,943 You can't move in space without also moving in time. 60 00:06:19,727 --> 00:06:22,773 Our voyage will take us a long way from home, 61 00:06:23,078 --> 00:06:26,124 a little more than a billion light-years. 62 00:06:26,298 --> 00:06:29,780 We're also traveling a billion years into the past, 63 00:06:29,954 --> 00:06:33,262 to an event so violent it will even shatter time. 64 00:06:44,795 --> 00:06:47,189 Now, we're getting close to our destination. 65 00:06:47,363 --> 00:06:49,626 This is what we came for. 66 00:06:52,716 --> 00:06:55,284 These two black holes were born from the collapse of a 67 00:06:55,458 --> 00:06:58,330 pair of massive stars. 68 00:06:58,983 --> 00:07:01,464 And they've been doing a gravitational tango ever since 69 00:07:01,856 --> 00:07:03,510 for millions of years. 70 00:07:03,684 --> 00:07:06,121 We're here for the climax. 71 00:07:06,382 --> 00:07:09,167 When those two collide, they will set off a space-time 72 00:07:09,341 --> 00:07:11,648 tsunami that will stretch and compress space 73 00:07:11,822 --> 00:07:13,345 in all directions. 74 00:07:13,520 --> 00:07:16,087 And it will slow down time itself, 75 00:07:16,261 --> 00:07:18,829 before speeding it up and slowing it down again. 76 00:07:25,314 --> 00:07:29,449 [distorted, echoes]. 77 00:07:45,552 --> 00:07:48,816 Gravitational... 78 00:07:49,381 --> 00:07:52,167 and it will slow down time itself... 79 00:07:53,777 --> 00:07:56,911 Set off a space-time tsunami... 80 00:07:57,215 --> 00:08:00,131 Stretch and compress space in all directions a billion 81 00:08:00,305 --> 00:08:02,133 light-years away. 82 00:08:05,093 --> 00:08:08,488 [grunts and exhales]. 83 00:08:10,838 --> 00:08:12,535 What does an event that took place more than a billion 84 00:08:12,709 --> 00:08:15,886 light-years away have to do with us? 85 00:08:16,365 --> 00:08:19,194 Albert Einstein was the first to understand that matter 86 00:08:19,368 --> 00:08:22,066 could send ripples across space-time. 87 00:08:22,414 --> 00:08:24,939 He imagined that catastrophic explosions of matter should 88 00:08:25,113 --> 00:08:28,420 create something much bigger than ripples, great waves, 89 00:08:29,378 --> 00:08:31,423 gravitational waves. 90 00:08:31,598 --> 00:08:34,383 You are seeing and hearing me right now, 91 00:08:34,557 --> 00:08:37,778 on whatever device you have, because we figured out a way 92 00:08:37,952 --> 00:08:40,955 to manipulate the electromagnetic spectrum. 93 00:08:41,259 --> 00:08:43,566 If we can learn to surf those gravitational waves the 94 00:08:43,740 --> 00:08:46,613 way we know how to ride the electromagnetic ones, 95 00:08:46,787 --> 00:08:48,440 who knows? 96 00:08:48,615 --> 00:08:51,792 It's as impossible to foresee as our world was to the 97 00:08:51,966 --> 00:08:54,272 scientists who experimented with electricity back 98 00:08:54,446 --> 00:08:56,971 in the 19th century. 99 00:08:57,145 --> 00:09:00,017 Cosmologists predicted the existence of black holes. 100 00:09:01,105 --> 00:09:04,369 Gravitational waves are the first direct evidence that 101 00:09:04,544 --> 00:09:06,763 black holes are real. 102 00:09:06,937 --> 00:09:09,287 But they may also provide a new way of knowing and 103 00:09:09,461 --> 00:09:11,159 exploring the cosmos. 104 00:09:11,333 --> 00:09:13,814 We can add it to the other senses that science has 105 00:09:13,988 --> 00:09:17,469 devised to penetrate the great dark ocean, 106 00:09:17,644 --> 00:09:20,560 all the kinds of light we use; gamma ray, 107 00:09:23,475 --> 00:09:26,957 X-ray, ultraviolet, 108 00:09:28,698 --> 00:09:32,093 infrared, microwave, 109 00:09:33,616 --> 00:09:37,751 radio wave and visible light. 110 00:09:39,448 --> 00:09:42,582 This newest way to search the cosmos could help us to one 111 00:09:42,756 --> 00:09:46,150 day know what's happening inside those black holes, 112 00:09:47,238 --> 00:09:49,371 and the other hidden places that make up most 113 00:09:49,545 --> 00:09:51,547 of the universe. 114 00:09:51,721 --> 00:09:54,637 What if we could detect the gravitational waves that were 115 00:09:54,811 --> 00:09:57,074 caused by the first moment of creation, 116 00:09:58,336 --> 00:10:00,643 the birth of the cosmos? 117 00:10:02,602 --> 00:10:06,127 What if we could extend our vision to see the whole sweep 118 00:10:06,301 --> 00:10:09,609 of 14 billion years of cosmic evolution? 119 00:10:22,622 --> 00:10:25,146 So, how did we get so smart? 120 00:10:26,495 --> 00:10:29,541 We know something about the evolution of our species, 121 00:10:29,716 --> 00:10:32,327 but how did the human mind evolve? 122 00:10:33,545 --> 00:10:36,374 Where did that crazy ambition to climb the ladder to the 123 00:10:36,548 --> 00:10:38,333 stars come from? 124 00:10:39,116 --> 00:10:43,599 How did we become a way for the universe to know itself? 125 00:10:45,775 --> 00:10:48,604 It started over there. 126 00:10:54,654 --> 00:10:57,352 TYSON: The Cosmic Calendar is a way for us to grasp the 127 00:10:57,526 --> 00:10:59,484 vastness of time. 128 00:10:59,659 --> 00:11:01,269 We've taken all of time, 129 00:11:01,443 --> 00:11:03,880 from the birth of the universe to this very moment, 130 00:11:04,054 --> 00:11:07,014 and compressed it into a single calendar year. 131 00:11:07,188 --> 00:11:09,494 On this scale, every month represents a little 132 00:11:09,669 --> 00:11:11,758 more than a billion years. 133 00:11:11,932 --> 00:11:15,196 Every day represents nearly 40 million years. 134 00:11:16,980 --> 00:11:19,809 Our own story begins with all the other life on 135 00:11:19,983 --> 00:11:22,116 our little world. 136 00:11:22,290 --> 00:11:25,206 Every living thing on Earth is descended from 137 00:11:25,380 --> 00:11:27,295 a single origin. 138 00:11:27,469 --> 00:11:31,168 It happened in the deep ocean darkness on September 15, 139 00:11:31,342 --> 00:11:34,432 about four billion years ago. 140 00:11:35,433 --> 00:11:39,699 Within this tiny single-celled organism was a kind of chemical ladder, 141 00:11:40,830 --> 00:11:43,267 the DNA double helix. 142 00:11:45,313 --> 00:11:47,707 Star stuff... 143 00:11:48,055 --> 00:11:50,971 Oxygen, carbon, nitrogen... 144 00:11:51,145 --> 00:11:54,104 Elements cooked in the hearts of distant stars, 145 00:11:54,278 --> 00:11:57,542 combined with hydrogen from the Big Bang to become alive 146 00:11:57,717 --> 00:12:00,023 on this little world. 147 00:12:00,328 --> 00:12:03,723 Through random changes, mutations in the genes, 148 00:12:03,897 --> 00:12:06,464 some of which led to more successful life-forms, 149 00:12:06,638 --> 00:12:09,119 what we call evolution by natural selection. 150 00:12:09,990 --> 00:12:14,646 The ladder grew, adding more and more rungs. 151 00:12:16,213 --> 00:12:19,695 It took another three billion years for life to evolve the 152 00:12:19,869 --> 00:12:23,090 complexity of the plants and animals that you could see 153 00:12:23,264 --> 00:12:25,440 with the naked eye. 154 00:12:31,663 --> 00:12:34,362 If the Cosmic Calendar had holidays, 155 00:12:34,536 --> 00:12:37,408 surely December 26 would be one of them. 156 00:12:38,105 --> 00:12:41,282 Some time on this day, about 200 million years ago, 157 00:12:42,718 --> 00:12:45,025 the first mammals evolved. 158 00:12:45,373 --> 00:12:47,636 They brought a new feature to life on Earth: 159 00:12:47,810 --> 00:12:50,291 the neocortex. 160 00:12:51,422 --> 00:12:52,946 Back in the Triassic, 161 00:12:53,120 --> 00:12:56,601 the odds were against her kind, but the dinosaurs that 162 00:12:56,776 --> 00:12:59,561 terrorized the mammals went extinct. 163 00:13:00,736 --> 00:13:03,652 It was the evolution of the neocortex in small, 164 00:13:03,826 --> 00:13:05,872 furtive creatures such as this one, 165 00:13:06,394 --> 00:13:10,050 that enabled their descendants to take over the planet. 166 00:13:10,615 --> 00:13:13,836 Mammals brought something else that was new. 167 00:13:14,054 --> 00:13:15,795 They suckled their young. 168 00:13:16,665 --> 00:13:18,536 They nurtured them. 169 00:13:18,710 --> 00:13:21,017 And there was love. 170 00:13:22,497 --> 00:13:25,674 Mother's Day on the Cosmic Calendar. 171 00:13:28,938 --> 00:13:32,420 Evolution by natural selection means that those living things 172 00:13:32,594 --> 00:13:35,640 able to better adapt to their environment are more likely to 173 00:13:35,815 --> 00:13:38,165 survive and leave offspring. 174 00:13:38,905 --> 00:13:42,560 Intelligence can be a huge selective advantage. 175 00:13:42,909 --> 00:13:46,564 The fate of this planet was changed forever by an event 176 00:13:46,738 --> 00:13:49,350 involving just 13 atoms. 177 00:13:49,654 --> 00:13:51,874 How small is 13 atoms? 178 00:13:52,048 --> 00:13:55,747 It's a quadrillionth the size of a grain of salt. 179 00:13:56,400 --> 00:14:00,230 A mutation occurred in the DNA of just one of our ancestors. 180 00:14:01,057 --> 00:14:04,713 Every source of self-esteem, everything we've learned, 181 00:14:04,887 --> 00:14:08,499 and built, might come down to nothing more than this. 182 00:14:10,371 --> 00:14:12,547 One base pair of a single gene. 183 00:14:13,591 --> 00:14:17,726 Just a single rung programmed the neocortex to grow larger 184 00:14:17,900 --> 00:14:19,902 still and fold more deeply. 185 00:14:20,729 --> 00:14:23,340 Maybe it was a random zap from a cosmic ray, 186 00:14:23,906 --> 00:14:26,953 or a simple error in transmission from one cell to another. 187 00:14:28,824 --> 00:14:32,567 Whatever it was, it led to a change in our species that 188 00:14:32,741 --> 00:14:35,222 would ultimately affect every other species 189 00:14:35,396 --> 00:14:37,964 of life on Earth. 190 00:14:38,616 --> 00:14:41,315 It happened late on New Year's Eve on this 191 00:14:41,489 --> 00:14:44,622 Cosmic Calendar of ours. 192 00:14:49,410 --> 00:14:51,803 To think that, for good or evil, 193 00:14:51,978 --> 00:14:55,155 our ability to feel loyalty and concern for increasingly 194 00:14:55,329 --> 00:14:58,767 larger groups, our obsession with certain belief systems, 195 00:14:59,463 --> 00:15:02,031 our capacity to imagine the future, 196 00:15:02,205 --> 00:15:06,253 our power to transform the world and to search the cosmos 197 00:15:06,427 --> 00:15:08,820 for answers... 198 00:15:09,125 --> 00:15:11,998 The very name we gave to our own species, 199 00:15:12,172 --> 00:15:16,350 homo sapiens, Latin for "wise persons" all of it 200 00:15:16,524 --> 00:15:20,920 comes down to nothing more than a single rung on our tiny 201 00:15:21,094 --> 00:15:23,270 DNA ladder to the stars. 202 00:15:26,926 --> 00:15:29,580 For much of the last hour on the Cosmic Calendar, 203 00:15:30,190 --> 00:15:32,453 for all but the last minute, 204 00:15:32,627 --> 00:15:34,977 our ancestors were hunters and gatherers, 205 00:15:36,500 --> 00:15:39,329 living in small bands. 206 00:15:45,683 --> 00:15:48,338 You know, when people just shrug and say 207 00:15:48,512 --> 00:15:51,689 "chalk it up to human nature," it puzzles me. 208 00:15:52,734 --> 00:15:54,779 They're usually talking about our greed, 209 00:15:54,954 --> 00:15:57,695 our arrogance, our violence. 210 00:15:57,869 --> 00:15:59,393 But we've been human for at least a couple of 211 00:15:59,567 --> 00:16:01,438 hundred thousand years. 212 00:16:01,612 --> 00:16:04,702 For most of that time we weren't that way at all. 213 00:16:05,573 --> 00:16:07,183 How do we know? 214 00:16:07,357 --> 00:16:09,881 From the accounts of explorers and anthropologists 215 00:16:10,056 --> 00:16:12,667 encountering surviving hunter-gatherer societies 216 00:16:12,841 --> 00:16:15,626 across four centuries. 217 00:16:15,800 --> 00:16:18,238 There are, of course, exceptions, especially in 218 00:16:18,412 --> 00:16:20,980 the circumstances of extreme scarcity. 219 00:16:21,154 --> 00:16:24,809 But the overwhelming consensus paints a picture of humans 220 00:16:24,984 --> 00:16:27,203 who lived in relative harmony with each other 221 00:16:27,377 --> 00:16:29,292 and the environment. 222 00:16:29,466 --> 00:16:32,252 We shared the little we had because we knew that our 223 00:16:32,426 --> 00:16:34,863 survival depended on the group. 224 00:16:35,429 --> 00:16:38,823 We didn't prize wealth beyond our needs because possessions 225 00:16:38,998 --> 00:16:41,043 would just weigh us down as we wandered. 226 00:16:42,044 --> 00:16:45,004 We were different from our non-human primate ancestors 227 00:16:45,178 --> 00:16:48,268 with their alpha-males bullying their way to dominance. 228 00:16:57,451 --> 00:17:00,019 And where was God? 229 00:17:01,933 --> 00:17:03,805 Everywhere. 230 00:17:03,979 --> 00:17:05,633 In the rocks and in the rivers, 231 00:17:05,807 --> 00:17:09,941 in the trees, in the birds and every living thing. 232 00:17:10,203 --> 00:17:12,118 And that was human nature for a couple of 233 00:17:12,292 --> 00:17:14,772 hundred thousand years. 234 00:17:15,164 --> 00:17:18,341 I'm standing on the southern tip of Africa and imagining 235 00:17:18,515 --> 00:17:20,691 what it was like some time in the last hundreds 236 00:17:20,865 --> 00:17:22,606 of thousands of years. 237 00:17:22,780 --> 00:17:26,958 Back then, Africa was home to all the world's homo sapiens... 238 00:17:28,134 --> 00:17:30,571 All 10,000 of them. 239 00:17:31,006 --> 00:17:33,965 If you were an extra-terrestrial on a survey mission, 240 00:17:34,140 --> 00:17:37,578 you might have thought we were an endangered species. 241 00:17:37,752 --> 00:17:41,625 Someday soon there will be ten billion of us. 242 00:17:41,799 --> 00:17:43,105 What happened? 243 00:17:43,279 --> 00:17:45,412 How did we become the globe-girdling, 244 00:17:45,586 --> 00:17:48,545 space-traveling species that we are today? 245 00:17:57,554 --> 00:18:01,036 Welcome to the first laboratory on Earth. 246 00:18:01,210 --> 00:18:03,995 We're in Blombos Cave where the evolution of the mind 247 00:18:04,170 --> 00:18:06,041 made a great leap. 248 00:18:06,215 --> 00:18:08,478 Our ancestors were conducting chemistry experiments 249 00:18:08,652 --> 00:18:12,613 here with a mineral rich in iron, ocher. 250 00:18:14,180 --> 00:18:17,270 They used it to decorate objects with bits of red color, 251 00:18:17,444 --> 00:18:19,837 but it may have also had other uses, 252 00:18:20,011 --> 00:18:21,796 to preserve animal hides or as a medicine, 253 00:18:22,971 --> 00:18:24,886 or as a way to sharpen their tools, 254 00:18:26,627 --> 00:18:29,108 or maybe as an insect repellent. 255 00:18:30,631 --> 00:18:32,850 And they engraved the ocher with symbols. 256 00:18:33,024 --> 00:18:36,767 Something completely new on the planet Earth, art. 257 00:18:38,421 --> 00:18:40,206 Not to be eaten. 258 00:18:40,380 --> 00:18:42,077 Not to provide shelter. 259 00:18:42,251 --> 00:18:44,775 But to symbolize something... 260 00:18:44,949 --> 00:18:47,169 Or just to be. 261 00:18:48,214 --> 00:18:49,650 It looks a little bit like a ladder, 262 00:18:49,824 --> 00:18:51,217 or a double helix. 263 00:18:51,391 --> 00:18:53,044 Whatever it was supposed to be, 264 00:18:53,219 --> 00:18:56,396 it's the earliest remnant we have of human culture. 265 00:18:56,787 --> 00:19:01,140 We had found a way to leave behind something distinctly human. 266 00:19:01,488 --> 00:19:04,839 A means to communicate, however enigmatically, 267 00:19:05,013 --> 00:19:09,365 to you and me 100,000 years away. 268 00:19:10,453 --> 00:19:13,369 A great power was discovered here in Blombos Cave. 269 00:19:21,203 --> 00:19:24,511 At 25 cosmic seconds-to-midnight, 270 00:19:24,685 --> 00:19:27,992 between 10,000 and 12,000 years ago, 271 00:19:28,776 --> 00:19:32,562 humans discovered another great power. 272 00:19:33,259 --> 00:19:35,739 Instead of foraging for food, 273 00:19:35,913 --> 00:19:38,481 we learned how to grow it in the earth. 274 00:19:39,917 --> 00:19:43,182 This changed everything. 275 00:19:43,617 --> 00:19:45,488 Our ancestors did something else they had 276 00:19:45,662 --> 00:19:47,360 never done before. 277 00:19:47,534 --> 00:19:49,971 They invented new tools, technology, 278 00:19:51,102 --> 00:19:54,105 to plant and pull food out of the earth. 279 00:19:54,845 --> 00:19:57,935 They settled down and moved indoors. 280 00:19:58,501 --> 00:20:01,330 Our relationship to nature, and to one another, 281 00:20:01,504 --> 00:20:04,115 would never be the same. 282 00:20:04,551 --> 00:20:06,944 This agricultural revolution, 283 00:20:07,118 --> 00:20:09,904 the domestication of plants and animals, 284 00:20:10,078 --> 00:20:13,124 is the mother of all revolutions because all 285 00:20:13,299 --> 00:20:15,605 others trace back to it. 286 00:20:15,779 --> 00:20:18,129 Its consequences reach far beyond even our 287 00:20:18,304 --> 00:20:20,610 own moment in time. 288 00:20:20,784 --> 00:20:22,612 Like most revolutions, 289 00:20:22,786 --> 00:20:25,659 this one brought change that was both great, 290 00:20:25,833 --> 00:20:27,356 and horrifying. 291 00:20:27,530 --> 00:20:31,360 There was a new concept in the world, "Home." 292 00:20:32,579 --> 00:20:35,669 A specific place on the planet where your ancestors, 293 00:20:35,843 --> 00:20:39,194 and you, were born and lived. 294 00:20:39,629 --> 00:20:42,458 And over time these settlements grew larger, 295 00:20:42,632 --> 00:20:48,203 until about 20 cosmic seconds ago or around 7000 BCE. 296 00:20:54,427 --> 00:20:56,864 Welcome to Catalhoyuk, 297 00:20:57,038 --> 00:20:59,519 a community on the Anatolian plain. 298 00:20:59,693 --> 00:21:02,739 It's about 9,000 years ago and everyone has settled 299 00:21:02,913 --> 00:21:05,046 in for the evening. 300 00:21:05,351 --> 00:21:08,310 Tonight, roughly the same number of people who once 301 00:21:08,484 --> 00:21:12,053 populated all of Africa are living together 302 00:21:12,227 --> 00:21:14,490 in this proto-city. 303 00:21:15,099 --> 00:21:17,580 The city is such a new idea, 304 00:21:17,754 --> 00:21:20,017 they haven't invented the street yet, 305 00:21:20,191 --> 00:21:21,976 or the window. 306 00:21:22,150 --> 00:21:24,718 So the only way you can get into your apartment is to walk 307 00:21:24,892 --> 00:21:27,721 along the rooftops till you arrive at the opening 308 00:21:27,895 --> 00:21:29,418 to your dwelling. 309 00:21:30,898 --> 00:21:33,727 Catalhoyuk lacked something much more significant than 310 00:21:33,901 --> 00:21:37,078 streets and windows. 311 00:21:37,687 --> 00:21:40,908 There is no palace here. 312 00:21:41,082 --> 00:21:43,563 The bitter price that the invention of agriculture cost 313 00:21:43,737 --> 00:21:46,827 human society had yet to be paid. 314 00:21:47,131 --> 00:21:50,918 Here, there was no dominance of the few over the many. 315 00:21:51,092 --> 00:21:54,356 There was no 1% attaining lavish wealth, 316 00:21:54,530 --> 00:21:57,577 while most everyone else merely subsisted. 317 00:21:57,751 --> 00:22:00,884 Forensic analysis of the women, men, and children 318 00:22:01,058 --> 00:22:04,410 who lived here show a remarkable similarity in diet. 319 00:22:05,802 --> 00:22:09,893 They still cherished the hunter-gatherer ethos of sharing. 320 00:22:10,503 --> 00:22:13,680 Catalhoyuk was egalitarian. 321 00:22:13,854 --> 00:22:16,944 The weakest ate the same food that the strongest did, 322 00:22:17,945 --> 00:22:21,165 and everyone lived in the same kind of home. 323 00:22:21,644 --> 00:22:24,081 But, man, it was anything but drab. 324 00:22:24,255 --> 00:22:27,041 Come on. I'll show you. 325 00:22:41,882 --> 00:22:45,276 TYSON: This was a typical apartment in one of the first cities, 326 00:22:46,277 --> 00:22:48,541 Catalhoyuk, in what is now Turkey, 327 00:22:48,715 --> 00:22:51,326 as it looked about 9,000 years ago. 328 00:22:53,415 --> 00:22:56,113 They were a lot like us. 329 00:22:57,637 --> 00:23:00,030 This bit of volcanic glass, 330 00:23:00,204 --> 00:23:02,685 called obsidian, made an excellent mirror. 331 00:23:06,080 --> 00:23:09,388 If we could only find a way to see all the things 332 00:23:09,562 --> 00:23:11,433 that were once reflected here. 333 00:23:15,132 --> 00:23:17,091 This apartment was home for an extended family of 334 00:23:17,265 --> 00:23:19,310 seven to ten people. 335 00:23:19,485 --> 00:23:21,400 Every apartment had a similar floor plan. 336 00:23:22,662 --> 00:23:27,536 Bedroom. Living room. Kitchen. 337 00:23:30,626 --> 00:23:32,933 Plaster auroch head. 338 00:23:33,107 --> 00:23:36,763 The people of Catalhoyuk had a passion for decorating. 339 00:23:37,024 --> 00:23:39,722 Apartments were richly appointed with the teeth and 340 00:23:39,896 --> 00:23:42,116 bones and skins of animals. 341 00:23:43,204 --> 00:23:45,859 The ocher that our ancestors picked up in Africa, 342 00:23:46,033 --> 00:23:49,558 about 100,000 years before, was now the medium of choice 343 00:23:50,646 --> 00:23:53,301 for the interior decorators of Catalhoyuk. 344 00:23:58,219 --> 00:24:01,048 And the red ocher had yet another profound application. 345 00:24:02,136 --> 00:24:05,705 They used it to create an entirely new art form: 346 00:24:06,009 --> 00:24:07,576 the map. 347 00:24:07,750 --> 00:24:09,970 For the first time ever, humans created a 348 00:24:10,144 --> 00:24:13,147 two-dimensional representation of their location 349 00:24:13,321 --> 00:24:15,715 in space and time. 350 00:24:17,325 --> 00:24:21,460 "This is where my home is in relation to the volcano." 351 00:24:22,548 --> 00:24:24,506 And with a few magical strokes, 352 00:24:24,680 --> 00:24:27,814 the artist sent a message across 9,000 years... 353 00:24:28,728 --> 00:24:32,471 "I was here when the volcano awakened." 354 00:24:41,392 --> 00:24:44,352 The experiment at Catalhoyuk was a success, 355 00:24:44,526 --> 00:24:47,921 and within a few thousand years there were cities everywhere. 356 00:24:57,931 --> 00:25:03,502 ♪ ♪ 357 00:25:05,504 --> 00:25:07,593 TYSON: When different kinds of people congregate 358 00:25:07,767 --> 00:25:09,290 in a single place, 359 00:25:09,464 --> 00:25:11,901 ideas are exchanged and new possibilities arise. 360 00:25:12,946 --> 00:25:15,296 The city is a kind of brain, 361 00:25:15,470 --> 00:25:17,864 creating and processing new ideas. 362 00:25:21,041 --> 00:25:23,086 Here, in the city of Amsterdam, 363 00:25:23,260 --> 00:25:25,654 in the 17th century, citizens of the old and 364 00:25:25,828 --> 00:25:28,483 new worlds mingled as they never had before, 365 00:25:29,440 --> 00:25:31,834 and there was an unprecedented freedom of thought. 366 00:25:32,835 --> 00:25:36,709 These conditions produced a golden age of science and art. 367 00:25:37,405 --> 00:25:40,451 In Italy, Giordano Bruno had proclaimed the existence 368 00:25:40,626 --> 00:25:42,062 of other worlds. 369 00:25:42,236 --> 00:25:45,761 For this he had been made to suffer. 370 00:25:46,849 --> 00:25:49,156 But a mere 50 years later in Holland, 371 00:25:49,330 --> 00:25:51,114 the astronomer Christiaan Huygens, 372 00:25:51,288 --> 00:25:54,422 who held the same belief, was showered with honors. 373 00:25:57,294 --> 00:26:01,037 Light was the central theme of the age: 374 00:26:01,429 --> 00:26:05,433 The enlightenment of human curiosity set free, 375 00:26:05,738 --> 00:26:08,131 and the light shed by Europe's first look at 376 00:26:08,305 --> 00:26:11,004 the once hidden realms of the planet. 377 00:26:11,831 --> 00:26:14,921 The light that permeated the paintings of the time, 378 00:26:15,095 --> 00:26:17,837 particularly the work of Vermeer. 379 00:26:19,142 --> 00:26:22,363 And light as an object of scientific inquiry. 380 00:26:23,625 --> 00:26:26,715 For generations, textile merchants had used a lens to 381 00:26:26,889 --> 00:26:29,326 examine the thread count of finely stitched fabrics. 382 00:26:30,501 --> 00:26:32,242 In the Amsterdam of that time, 383 00:26:32,416 --> 00:26:34,418 there lived three men whose passion for 384 00:26:34,593 --> 00:26:38,858 light inspired them to use that ancient device in a completely new way. 385 00:26:40,337 --> 00:26:43,384 They aimed the textile merchants' lens at objects no 386 00:26:43,558 --> 00:26:46,692 one had ever thought to examine closely before. 387 00:26:47,127 --> 00:26:50,173 It became a window, an aperture for finding and 388 00:26:50,347 --> 00:26:52,785 exploring new worlds. 389 00:26:53,176 --> 00:26:56,484 Antonie Van Leeuwenhoek used a single lens to reveal 390 00:26:56,658 --> 00:26:59,400 the teeming microcosm in a drop of water. 391 00:27:07,277 --> 00:27:08,931 His friend, 392 00:27:09,105 --> 00:27:11,194 Christiaan Huygens used two lenses to bring the stars, 393 00:27:11,368 --> 00:27:13,980 planets, and moons close enough to 394 00:27:14,154 --> 00:27:16,112 reveal their features. 395 00:27:16,896 --> 00:27:20,029 Huygens became the first to see that Saturn's rings did not 396 00:27:20,203 --> 00:27:24,425 touch the planet, and the first to understand what they really were. 397 00:27:26,166 --> 00:27:28,951 He also discovered Saturn's largest moon, Titan. 398 00:27:30,474 --> 00:27:31,998 Huygens, like Bruno, 399 00:27:32,172 --> 00:27:34,783 believed that the stars were other suns, 400 00:27:34,957 --> 00:27:38,221 orbited by their own systems of planets and moons. 401 00:27:38,787 --> 00:27:41,094 But why was there no hint of those other worlds and 402 00:27:41,268 --> 00:27:45,315 their living things in the sacred books? 403 00:27:46,882 --> 00:27:49,537 Whatever disquiet this contradiction may have stirred 404 00:27:49,711 --> 00:27:52,801 in the hearts and minds of the leaders of the Enlightenment, 405 00:27:52,975 --> 00:27:56,544 there was only one man who dared to address it head-on. 406 00:27:56,849 --> 00:27:59,634 He was another wizard of light. 407 00:27:59,808 --> 00:28:02,158 Baruch Spinoza had been a member of the Jewish 408 00:28:02,332 --> 00:28:04,857 congregation of Amsterdam through his teenage years. 409 00:28:06,075 --> 00:28:08,687 But in his early 20s, he began to speak publicly of 410 00:28:08,861 --> 00:28:11,167 a new vision of God. 411 00:28:12,560 --> 00:28:15,519 Spinoza's God was the physical laws of the universe. 412 00:28:17,391 --> 00:28:20,524 His sacred text, the book of nature. 413 00:28:23,310 --> 00:28:25,442 The Jews of Amsterdam were mostly refugees from 414 00:28:25,616 --> 00:28:28,576 the vicious Inquisitions in Spain and Portugal, 415 00:28:28,924 --> 00:28:31,797 where so many of them had been tortured and murdered. 416 00:28:33,842 --> 00:28:36,802 Amsterdam had offered the Jews a refuge, 417 00:28:36,976 --> 00:28:39,282 and they must have seen Spinoza's radical ideas as a 418 00:28:39,456 --> 00:28:42,459 threat to their hard-won security in Holland. 419 00:28:43,156 --> 00:28:44,984 They excommunicated the young rebel, 420 00:28:45,158 --> 00:28:47,813 and decreed that he must be forever shunned. 421 00:28:48,465 --> 00:28:51,642 Spinoza accepted their punishment with dignity, 422 00:28:51,817 --> 00:28:54,210 but without a trace of submission. 423 00:28:54,384 --> 00:28:56,386 He moved nearby, to The Hague. 424 00:28:56,560 --> 00:28:59,738 Where he went even further, daring to write that the Bible 425 00:28:59,912 --> 00:29:03,698 was not dictated by God, but written by human beings. 426 00:29:04,177 --> 00:29:05,613 Spinoza wrote: 427 00:29:05,787 --> 00:29:07,963 "Do not look for God in miracles. 428 00:29:08,137 --> 00:29:11,010 Miracles are violations of the laws of nature. 429 00:29:11,532 --> 00:29:14,535 God is best apprehended in the study of those laws." 430 00:29:16,363 --> 00:29:19,148 No one had ever said these things aloud before. 431 00:29:19,714 --> 00:29:23,022 Spinoza knew that he was testing the limits of free thought, 432 00:29:23,196 --> 00:29:25,241 even for Holland. 433 00:29:28,418 --> 00:29:31,726 To him, an official state religion was more than 434 00:29:31,900 --> 00:29:35,077 spiritual coercion of the individual. 435 00:29:35,251 --> 00:29:38,385 Spinoza regarded the miraculous events of the major 436 00:29:38,559 --> 00:29:41,823 religious traditions as organized superstition. 437 00:29:43,346 --> 00:29:46,872 In his view, magical thinking posed a danger to 438 00:29:47,046 --> 00:29:50,789 the future citizens of a rational, free society. 439 00:29:51,920 --> 00:29:54,488 There could be no such thing as democracy without the 440 00:29:54,662 --> 00:29:57,317 separation of church and state. 441 00:29:57,491 --> 00:30:00,233 He wrote a book that introduced the ideas at the 442 00:30:00,407 --> 00:30:03,758 heart of the American and many another revolution. 443 00:30:05,760 --> 00:30:08,545 Then, as now, there were those who were threatened 444 00:30:08,719 --> 00:30:10,765 by this view of God. 445 00:30:11,548 --> 00:30:13,028 [grunting]. 446 00:30:21,950 --> 00:30:24,431 Spinoza continued to write and speak about his 447 00:30:24,605 --> 00:30:27,086 revolutionary view of God, 448 00:30:27,260 --> 00:30:30,045 always wearing the slashed cape as a badge of honor. 449 00:30:32,308 --> 00:30:36,182 He died at 44, possibly from inhaling particles of dust 450 00:30:36,356 --> 00:30:38,271 during his years of grinding lenses for 451 00:30:38,445 --> 00:30:40,577 microscopes and telescopes. 452 00:30:41,927 --> 00:30:45,756 250 years later, another man with a passion for light made 453 00:30:45,931 --> 00:30:48,281 a pilgrimage to the humble workroom that had been 454 00:30:48,455 --> 00:30:51,066 preserved as a testament to the vast influence of 455 00:30:51,240 --> 00:30:53,155 Spinoza's philosophy. 456 00:30:53,329 --> 00:30:57,072 This man, world famous for finding a new law of nature, 457 00:30:57,246 --> 00:31:00,380 was often asked if he believed in God. 458 00:31:00,554 --> 00:31:02,643 Albert Einstein replied: 459 00:31:03,252 --> 00:31:09,215 "I believe in Spinoza's God, who reveals himself in the harmony of all that exists." 460 00:31:13,219 --> 00:31:16,396 Our understanding of nature's laws has advanced far beyond 461 00:31:16,570 --> 00:31:19,573 Spinoza's, and even Einstein's wildest dreams. 462 00:31:20,922 --> 00:31:24,578 But there is one law of nature we cannot seem to grasp. 463 00:31:25,187 --> 00:31:27,973 Inscribed in the book of nature is a parable about an 464 00:31:28,147 --> 00:31:30,714 ancient alliance between two kingdoms. 465 00:31:31,498 --> 00:31:34,631 And those who would tear it apart. 466 00:31:47,035 --> 00:31:49,603 TYSON: Long ago, there were two kingdoms. 467 00:31:49,777 --> 00:31:51,997 An alliance was formed between them, 468 00:31:52,171 --> 00:31:55,174 one that would bring them both riches beyond measure. 469 00:31:55,826 --> 00:32:00,005 A partnership lasting more than a 100 million years. 470 00:32:00,179 --> 00:32:04,357 And then a new kind of being evolved in one of the two kingdoms. 471 00:32:04,923 --> 00:32:09,492 Its descendants plundered the riches and violated the alliance. 472 00:32:09,840 --> 00:32:13,148 In their arrogance, they became a mortal danger to both 473 00:32:13,322 --> 00:32:16,108 kingdoms and to themselves. 474 00:32:27,815 --> 00:32:30,078 This parable is true. 475 00:32:30,252 --> 00:32:33,864 It's the story of two of the half dozen realms of life on Earth, 476 00:32:34,039 --> 00:32:37,085 the plant and animal kingdoms. 477 00:32:37,825 --> 00:32:40,567 It's not easy being green. 478 00:32:41,785 --> 00:32:45,224 Sex is challenging when you're stuck in one place. 479 00:32:45,398 --> 00:32:46,965 There's no dating. 480 00:32:47,139 --> 00:32:49,706 You just sit there and cast your seed to the winds. 481 00:32:50,838 --> 00:32:52,187 Literally. 482 00:32:52,361 --> 00:32:54,755 You just wait for the wind to blow. 483 00:32:54,929 --> 00:32:57,062 If you get lucky, some of your pollen will 484 00:32:57,236 --> 00:33:00,065 be carried away and land on the sexual reproductive part 485 00:33:00,239 --> 00:33:02,632 of another plant. 486 00:33:02,806 --> 00:33:05,157 The plants played this hit-or-miss game of chance for 487 00:33:05,331 --> 00:33:07,550 a couple of hundred million years, 488 00:33:07,724 --> 00:33:11,424 until insects evolved to play cupid. 489 00:33:15,689 --> 00:33:18,387 What resulted was one of the great co-evolution marriages 490 00:33:18,561 --> 00:33:20,389 in the history of life. 491 00:33:20,563 --> 00:33:22,913 The insect would visit a flower for a dinner of 492 00:33:23,088 --> 00:33:25,307 protein-rich pollen. 493 00:33:25,481 --> 00:33:28,223 Inevitably, some of the pollen would stick to the body 494 00:33:28,397 --> 00:33:30,095 of the insect. 495 00:33:30,269 --> 00:33:32,140 The insect would visit another flower, 496 00:33:32,314 --> 00:33:35,013 bringing along the leftovers on its body. 497 00:33:35,578 --> 00:33:38,581 That pollen fertilized the next flower, 498 00:33:38,755 --> 00:33:40,931 allowing it to reproduce. 499 00:33:41,889 --> 00:33:45,153 It was a win-win deal for both the flowers and the insects, 500 00:33:45,980 --> 00:33:48,591 causing a series of delightful evolutionary developments. 501 00:33:49,897 --> 00:33:52,639 A new plant arose that produced sugary nectar in 502 00:33:52,813 --> 00:33:54,815 addition to the pollen. 503 00:33:54,989 --> 00:33:58,601 Now, the insects came not just for their basic meal of pollen, 504 00:33:59,254 --> 00:34:01,691 but also for dessert. 505 00:34:02,301 --> 00:34:05,739 The insects got chubbier, evolved furry bodies and even 506 00:34:05,913 --> 00:34:08,959 little pouches on their legs to snag more pollen on their 507 00:34:09,134 --> 00:34:11,353 daily rounds in the flowers. 508 00:34:13,703 --> 00:34:15,879 Now there were bees. 509 00:34:17,011 --> 00:34:19,100 This was a bonus for yet another species of 510 00:34:19,274 --> 00:34:20,928 the animal kingdom... 511 00:34:21,102 --> 00:34:22,930 Us. 512 00:34:26,368 --> 00:34:29,197 We are indebted to the bees and their fellow pollinators 513 00:34:29,371 --> 00:34:32,679 for something even more vital to our survival. 514 00:34:32,940 --> 00:34:36,335 Every third bite of food you take-and this is even true for 515 00:34:36,509 --> 00:34:40,252 those of us who are omnivores, was made possible by them. 516 00:34:41,122 --> 00:34:44,647 35% of the world's crops depend on their cooperation. 517 00:34:45,518 --> 00:34:47,737 The plants eat starlight... 518 00:34:47,911 --> 00:34:51,219 And we, and the animals, we eat plants. 519 00:34:52,220 --> 00:34:55,310 And they don't just increase the quantity of available food. 520 00:34:55,484 --> 00:34:58,313 We owe them for much of the biodiversity that has made our 521 00:34:58,487 --> 00:35:01,751 food supply so dependable. 522 00:35:01,925 --> 00:35:04,189 But we're working them to death. 523 00:35:04,363 --> 00:35:06,016 And for the first time ever, 524 00:35:06,191 --> 00:35:10,673 many kinds of bees are on the endangered species list. 525 00:35:22,685 --> 00:35:25,601 I think you know where this is headed. 526 00:35:34,958 --> 00:35:38,484 The blessing and the curse of the invention of agriculture 527 00:35:38,658 --> 00:35:41,095 has brought us here, to the Halls of Extinction. 528 00:35:51,758 --> 00:35:55,892 A memorial to all the living things lost in the mass 529 00:35:56,066 --> 00:35:58,634 extinction events in Earth's history. 530 00:35:59,548 --> 00:36:04,162 It's a monument to the broken branches on the tree of life. 531 00:36:05,250 --> 00:36:08,078 Five times in the history of life, 532 00:36:08,253 --> 00:36:11,691 cataclysmic geological, and astronomical events, 533 00:36:11,865 --> 00:36:16,435 have threatened to extinguish life itself. 534 00:36:18,176 --> 00:36:21,527 The sixth one is different. 535 00:36:21,788 --> 00:36:24,747 The last time we were here together this hallway 536 00:36:24,921 --> 00:36:26,532 had no name. 537 00:36:26,706 --> 00:36:28,273 Why? 538 00:36:28,447 --> 00:36:30,623 Because back then a scientific consensus had yet 539 00:36:30,797 --> 00:36:35,715 to be reached that we were in the midst of a mass extinction event. 540 00:36:35,889 --> 00:36:37,369 That's changed. 541 00:36:37,543 --> 00:36:40,720 Now, this hallway has a name. 542 00:36:41,460 --> 00:36:43,462 It's ours. 543 00:36:43,636 --> 00:36:46,682 The Anthropocene. 544 00:36:48,031 --> 00:36:53,211 "Anthropo" from the Greek word for "human" and "Cene." 545 00:36:54,777 --> 00:36:57,476 the Greek word for "recent." 546 00:37:14,971 --> 00:37:17,670 TYSON: These are the species we hunted to extinction back 547 00:37:17,844 --> 00:37:20,281 when we were wanderers. 548 00:37:20,542 --> 00:37:23,980 Including our own cousins, the Neanderthals. 549 00:37:39,518 --> 00:37:41,781 What is it about us, as a species, 550 00:37:41,955 --> 00:37:45,741 that wherever we go, we bring death? 551 00:37:49,876 --> 00:37:52,922 Beyond here lies the future. 552 00:37:53,096 --> 00:37:56,926 Even now it's not too late to keep this corridor from lengthening. 553 00:37:59,015 --> 00:38:01,844 If we fail... 554 00:38:05,326 --> 00:38:08,590 [children playing]. 555 00:38:13,160 --> 00:38:15,815 But if we succeed... 556 00:38:16,119 --> 00:38:17,904 Come with me. 557 00:38:31,309 --> 00:38:34,834 TYSON: In a possible future only decades away, 558 00:38:35,008 --> 00:38:39,360 project Starshot, a flotilla of 1,000 spacecraft, 559 00:38:39,534 --> 00:38:41,710 will depart from Earth. 560 00:38:41,884 --> 00:38:44,931 This part of the Atacama Desert west of the Andes Mountains, 561 00:38:45,105 --> 00:38:48,456 is so dry that it hasn't rained in recorded history. 562 00:38:49,936 --> 00:38:52,808 And that's great for us because we're going to need 563 00:38:52,982 --> 00:38:54,767 the clearest of skies. 564 00:39:27,016 --> 00:39:29,497 There were no witnesses when the first life left the 565 00:39:29,671 --> 00:39:32,631 water for the land. 566 00:39:32,892 --> 00:39:35,373 There was nobody to file a report when the first birds 567 00:39:35,547 --> 00:39:37,853 took to the skies. 568 00:39:38,027 --> 00:39:40,465 But this is one great leap that will be documented in 569 00:39:40,639 --> 00:39:43,032 every conceivable way. 570 00:39:43,206 --> 00:39:45,731 The whole world is watching. 571 00:39:46,688 --> 00:39:49,648 We are, after all, sending our first craft directly to the 572 00:39:49,822 --> 00:39:53,391 planets of another sun: the Alpha Centauri system. 573 00:39:56,829 --> 00:40:00,136 These are the ships that will carry our senses there. 574 00:40:00,310 --> 00:40:04,053 These are interstellar sailing ships propelled by light. 575 00:40:04,663 --> 00:40:08,188 Their hulls weigh but a gram, and they are no larger than a 576 00:40:08,362 --> 00:40:11,844 pea, and yet they're equipped with all that NASA's Voyagers 577 00:40:12,018 --> 00:40:14,150 have and more. 578 00:40:23,725 --> 00:40:26,685 When the first light blasts forth from this phased array 579 00:40:26,859 --> 00:40:31,037 of lasers, the spacecraft will accelerate from zero to 20% of 580 00:40:31,211 --> 00:40:34,780 the speed of light in mere minutes. 581 00:40:35,041 --> 00:40:37,957 Inside each nanocraft is everything needed to perform 582 00:40:38,131 --> 00:40:41,917 the preliminary reconnaissance of the worlds of another star 583 00:40:42,091 --> 00:40:45,051 and return that visual and scientific information 584 00:40:45,225 --> 00:40:47,357 back to Earth. 585 00:40:48,707 --> 00:40:51,057 Space is mostly empty, 586 00:40:51,231 --> 00:40:53,059 but there are tiny dust particles that could 587 00:40:53,233 --> 00:40:55,931 wreak havoc if they were to collide with nanocraft 588 00:40:56,105 --> 00:40:57,933 traveling at such high speeds. 589 00:41:09,336 --> 00:41:11,730 That's one of the reasons we need to send so many of them. 590 00:41:18,432 --> 00:41:22,088 Voyager 1 is traveling at 38,000 miles per hour. 591 00:41:23,176 --> 00:41:26,266 It left home more than 40 years ago. 592 00:41:27,615 --> 00:41:30,139 It will take these nanocraft only four days 593 00:41:30,313 --> 00:41:31,880 to overtake her. 594 00:41:32,054 --> 00:41:33,534 That's pretty fast, 595 00:41:33,708 --> 00:41:36,581 but still only 20% of the speed of light. 596 00:41:36,755 --> 00:41:39,801 Proxima Centauri is four light-years away. 597 00:41:39,975 --> 00:41:42,108 That's a 20 year one-way trip. 598 00:41:45,154 --> 00:41:47,635 Orbiting Proxima Centauri, there is a world in the 599 00:41:47,809 --> 00:41:51,465 habitable zone where we think life might flourish. 600 00:41:54,424 --> 00:41:56,775 Our robotic emissaries will send accounts from 601 00:41:56,949 --> 00:41:59,691 these new worlds. 602 00:41:59,995 --> 00:42:02,476 Their messages will race back to us on radio waves 603 00:42:02,650 --> 00:42:04,434 at the speed of light. 604 00:42:04,609 --> 00:42:08,090 They'll take four years to reach us: 20 years one-way, 605 00:42:08,787 --> 00:42:10,615 four years back. 606 00:42:10,789 --> 00:42:13,922 That's a 24-year round-trip. 607 00:42:14,270 --> 00:42:18,710 Many of you will be there then to read and to write those new 608 00:42:18,884 --> 00:42:21,190 pages in the book of nature, 609 00:42:21,364 --> 00:42:24,280 and to chart our future course of wandering... 610 00:42:42,647 --> 00:42:47,303 ♪ ♪ 611 00:42:47,956 --> 00:42:50,306 No longer bounded by the earth, 612 00:42:50,480 --> 00:42:53,005 the ocean, 613 00:42:53,179 --> 00:42:55,877 or the sky. 614 00:43:07,367 --> 00:43:13,765 ♪ ♪ 615 00:43:14,635 --> 00:43:16,463 Captioned by Cotter Captioning Services.