1 00:00:37,446 --> 00:00:41,644 NARRATOR: "I call Heaven and Earth to witness against you this day... 2 00:00:41,850 --> 00:00:45,684 ...that I have set before thee life and death... 3 00:00:45,888 --> 00:00:48,550 ...the blessing and the curse. 4 00:00:48,757 --> 00:00:51,920 Therefore choose life, that thou mayest live... 5 00:00:52,127 --> 00:00:54,687 ...thou and thy seed." 6 00:01:09,111 --> 00:01:12,137 SAGAN: Nearly 200 years ago, in the Gulf of Alaska... 7 00:01:12,347 --> 00:01:14,178 ...at a place called Lituya Bay... 8 00:01:14,383 --> 00:01:19,286 ...two cultures that had never met experienced a first encounter. 9 00:01:20,055 --> 00:01:21,249 The Tlingit people... 10 00:01:21,456 --> 00:01:24,789 ...lived more or less as their ancestors had for thousands of years. 11 00:01:24,993 --> 00:01:26,085 They were nomads... 12 00:01:26,295 --> 00:01:29,264 ...moving often by canoe between numerous campsites... 13 00:01:29,464 --> 00:01:32,160 ...where they caught plentiful fish and sea otters... 14 00:01:32,367 --> 00:01:34,528 ...and traded with neighboring tribes. 15 00:01:39,174 --> 00:01:42,940 (SPEAKS IN TLINGIT) 16 00:01:43,545 --> 00:01:46,275 The creator they worshiped was the raven god... 17 00:01:46,481 --> 00:01:50,008 ...whom they pictured as an enormous black bird with white wings. 18 00:01:50,218 --> 00:01:52,709 And one July day in 1786... 19 00:01:53,021 --> 00:01:55,216 ...the raven god appeared. 20 00:01:58,660 --> 00:02:00,457 The Tlingit were terrified. 21 00:02:00,662 --> 00:02:05,326 They knew that anyone looking directly at the god would be turned to stone. 22 00:02:13,008 --> 00:02:16,136 From the other side of the planet had come an expedition... 23 00:02:16,345 --> 00:02:18,870 ...led by the French explorer La Pérouse. 24 00:02:19,081 --> 00:02:24,018 It was the most elaborately planned scientific voyage of the century... 25 00:02:24,252 --> 00:02:27,813 ...sent around the world to gather knowledge about the geography... 26 00:02:28,023 --> 00:02:31,390 ...natural history and peoples of distant lands. 27 00:02:36,098 --> 00:02:37,463 But to the Tlingit... 28 00:02:37,666 --> 00:02:42,160 ...whose world was confined to the islands and inlets of south Alaska... 29 00:02:42,371 --> 00:02:46,808 ...this great vessel could have come only from the gods. 30 00:02:51,580 --> 00:02:55,482 There was one among them who dared to look more deeply. 31 00:02:55,684 --> 00:02:58,414 He was an old warrior, and nearly blind. 32 00:02:58,887 --> 00:03:01,583 He said that his life was almost over. 33 00:03:01,790 --> 00:03:04,486 For the common good, he would approach the raven... 34 00:03:04,693 --> 00:03:09,630 ...to learn whether the god really would turn his people to stone. 35 00:03:24,146 --> 00:03:27,638 He set out on his own voyage of discovery... 36 00:03:27,983 --> 00:03:31,214 ...to confront the end of the world. 37 00:04:39,221 --> 00:04:42,713 The old man made himself look hard at the raven... 38 00:04:42,924 --> 00:04:46,052 ...and saw that it was not a great bird from the sky... 39 00:04:46,261 --> 00:04:49,094 ...but the work of men like himself. 40 00:04:53,935 --> 00:04:57,132 This first encounter turned out to be peaceful. 41 00:04:57,339 --> 00:05:00,433 Men of the La Pérouse expedition were under orders... 42 00:05:00,642 --> 00:05:04,043 ...to treat with respect any people they might discover. 43 00:05:04,246 --> 00:05:07,875 An exceptional policy for its time, and after. 44 00:05:08,083 --> 00:05:10,745 La Pérouse and the Tlingit exchanged goods... 45 00:05:10,952 --> 00:05:15,582 ...and then the strange ship sailed away, never to return. 46 00:05:16,725 --> 00:05:21,025 Not all encounters between nations had been so peaceful. 47 00:05:22,097 --> 00:05:24,065 Before 1519... 48 00:05:24,266 --> 00:05:26,666 ...the Aztecs of Mexico had never seen a gun. 49 00:05:26,868 --> 00:05:29,803 They too believed at first that their strange visitors... 50 00:05:30,005 --> 00:05:32,098 ...had come from the sky. 51 00:05:45,587 --> 00:05:47,248 The Spaniards under Cortez... 52 00:05:47,455 --> 00:05:50,424 ...were not constrained by any injunctions against violence. 53 00:05:50,625 --> 00:05:54,584 Their true nature and intentions soon became clear. 54 00:06:10,145 --> 00:06:12,045 Unlike the La Pérouse expedition... 55 00:06:12,247 --> 00:06:15,978 ...the Conquistadors sought, not knowledge, but gold. 56 00:06:16,685 --> 00:06:20,348 They used their superior weapons to loot and murder. 57 00:06:20,555 --> 00:06:25,185 In their madness, they obliterated a civilization. 58 00:06:32,534 --> 00:06:34,434 In the name of piety... 59 00:06:34,636 --> 00:06:36,501 ...in a mockery of their religion... 60 00:06:36,705 --> 00:06:39,640 ...the Spaniards utterly destroyed a society... 61 00:06:39,841 --> 00:06:42,332 ...with an art, astronomy, and architecture... 62 00:06:42,544 --> 00:06:44,739 ...the equal of anything in Europe. 63 00:06:48,016 --> 00:06:51,952 We revile the Conquistadors for their cruelty and shortsightedness... 64 00:06:52,153 --> 00:06:53,814 ...for choosing death. 65 00:06:54,022 --> 00:06:58,049 We admire La Pérouse and the Tlingit for their courage and wisdom... 66 00:06:58,260 --> 00:07:00,854 ...for choosing life. 67 00:07:01,062 --> 00:07:03,030 The choice is with us still. 68 00:07:03,231 --> 00:07:07,668 But the civilization now in jeopardy is all humanity. 69 00:07:09,838 --> 00:07:11,863 As the ancient mythmakers knew... 70 00:07:12,073 --> 00:07:15,133 ...we're children equally of the Earth and sky. 71 00:07:15,343 --> 00:07:17,470 In our tenure on this planet... 72 00:07:17,679 --> 00:07:21,115 ...we've accumulated dangerous evolutionary baggage: 73 00:07:21,316 --> 00:07:23,648 Propensities for aggression and ritual... 74 00:07:23,852 --> 00:07:27,720 ...submission to leaders, hostility to outsiders. 75 00:07:27,922 --> 00:07:31,380 All of which puts our survival in some doubt. 76 00:07:31,593 --> 00:07:34,084 But we've also acquired compassion for others... 77 00:07:34,296 --> 00:07:35,422 ...love for our children... 78 00:07:35,630 --> 00:07:38,326 ...a desire to learn from history and experience... 79 00:07:38,533 --> 00:07:42,264 ...and a great, soaring, passionate intelligence. 80 00:07:42,470 --> 00:07:47,169 The clear tools for our continued survival and prosperity. 81 00:07:52,147 --> 00:07:54,775 Which aspects of our nature will prevail... 82 00:07:54,983 --> 00:07:56,314 ...is uncertain. 83 00:07:56,518 --> 00:08:00,284 Particularly when our visions and prospects are bound... 84 00:08:00,488 --> 00:08:04,356 ...to one small part of the small planet Earth. 85 00:08:04,559 --> 00:08:06,220 But up there in the cosmos... 86 00:08:06,428 --> 00:08:09,591 ...an inescapable perspective awaits. 87 00:08:09,798 --> 00:08:13,928 National boundaries are not evident when we view the Earth from space. 88 00:08:14,135 --> 00:08:17,434 Fanatic ethnic or religious or national identifications... 89 00:08:17,639 --> 00:08:19,539 ...are difficult to support... 90 00:08:19,741 --> 00:08:23,108 ...when we see our planet as a fragile blue crescent... 91 00:08:23,311 --> 00:08:26,474 ...fading to become an inconspicuous point of light... 92 00:08:26,681 --> 00:08:31,050 ...against the bastion and citadel of the stars. 93 00:08:31,886 --> 00:08:35,049 There are not yet obvious signs of extraterrestrial intelligence... 94 00:08:35,256 --> 00:08:38,384 ...and this makes us wonder whether civilizations like ours... 95 00:08:38,593 --> 00:08:42,427 ...rush inevitably, headlong to self-destruction. 96 00:08:42,630 --> 00:08:43,995 I dream about it. 97 00:08:44,199 --> 00:08:47,657 And sometimes they're bad dreams. 98 00:09:00,582 --> 00:09:02,311 In the vision of a dream... 99 00:09:02,517 --> 00:09:04,348 ...I once imagined myself... 100 00:09:04,552 --> 00:09:08,147 ...searching for other civilizations in the cosmos. 101 00:09:08,356 --> 00:09:10,688 Among a hundred billion galaxies... 102 00:09:10,892 --> 00:09:12,883 ...and a billion trillion stars... 103 00:09:13,094 --> 00:09:17,588 ...life and intelligence should have arisen on many worlds. 104 00:09:19,601 --> 00:09:23,332 Some worlds are barren and desolate... 105 00:09:23,538 --> 00:09:25,665 ...on them life never began... 106 00:09:25,874 --> 00:09:30,004 ...or may have been extinguished in some cosmic catastrophe. 107 00:09:30,211 --> 00:09:32,145 There may be worlds rich in life... 108 00:09:32,347 --> 00:09:37,182 ...but not yet evolved to intelligence and high technology. 109 00:09:37,385 --> 00:09:40,582 There may be civilizations that achieve technology... 110 00:09:40,789 --> 00:09:44,919 ...and then promptly use it to destroy themselves. 111 00:09:45,126 --> 00:09:47,686 And perhaps there are also beings... 112 00:09:47,896 --> 00:09:50,626 ...who learned to live with their technology and themselves. 113 00:09:50,832 --> 00:09:52,595 Beings who endure... 114 00:09:52,801 --> 00:09:56,828 ...and become citizens of the cosmos. 115 00:10:09,184 --> 00:10:10,845 Immersed in these thoughts... 116 00:10:11,052 --> 00:10:14,749 ...I found myself approaching a world that was clearly inhabited... 117 00:10:14,956 --> 00:10:17,424 ...a world I had visited before. 118 00:10:17,625 --> 00:10:21,083 I saw a planet encompassed by light... 119 00:10:21,296 --> 00:10:25,027 ...and recognized the signature of intelligence. 120 00:10:30,071 --> 00:10:31,538 But suddenly... 121 00:10:31,739 --> 00:10:35,869 ...darkness, total and absolute. 122 00:10:46,988 --> 00:10:48,216 In my dream... 123 00:10:48,423 --> 00:10:51,017 ...I could read the Book of Worlds. 124 00:10:51,226 --> 00:10:52,955 A vast encyclopedia... 125 00:10:53,161 --> 00:10:56,426 ...of a billion planets within the Milky Way. 126 00:11:13,681 --> 00:11:15,876 What could the computer tell me... 127 00:11:16,084 --> 00:11:19,850 ...about this now-darkened world? 128 00:11:30,064 --> 00:11:33,932 They must have survived some earlier catastrophe. 129 00:11:37,138 --> 00:11:39,868 Locally initiated contact: 130 00:11:40,074 --> 00:11:42,304 Maybe their television broadcasts. 131 00:11:44,178 --> 00:11:47,614 Their biology was different from ours. 132 00:11:50,652 --> 00:11:51,949 High technology. 133 00:11:52,153 --> 00:11:55,088 I wondered what those lights had been for. 134 00:11:57,892 --> 00:12:00,053 There must have been signs of trouble. 135 00:12:00,261 --> 00:12:02,627 Probability of survival in a century... 136 00:12:02,830 --> 00:12:05,958 ...less than 1%. Not very good odds. 137 00:12:08,102 --> 00:12:11,299 "Communications interrupted." 138 00:12:11,506 --> 00:12:13,474 Their world society had failed. 139 00:12:13,675 --> 00:12:16,803 They had made the ultimate mistake. 140 00:12:18,179 --> 00:12:22,115 I felt a longing to return to Earth. 141 00:12:23,985 --> 00:12:27,352 The television transmissions of Earth rushed past me... 142 00:12:27,555 --> 00:12:31,321 ...expanding away from our planet at the speed of light. 143 00:12:31,526 --> 00:12:35,986 (RANDOM TELEVISION AUDIO PLAYS) 144 00:12:42,470 --> 00:12:45,371 ANNOUNCER 1: The nuclear test-ban treaty was signed today. 145 00:12:45,573 --> 00:12:48,167 ANNOUNCER 2: Something's happened in the motorcade. Stand by. 146 00:12:48,376 --> 00:12:50,970 ANNOUNCER 3: For 64,000 dollars... 147 00:12:51,179 --> 00:12:54,410 ANNOUNCER 4:... bombing of Hanoi was designed to cripple morale... 148 00:12:58,052 --> 00:13:01,818 NIXON: There can be no whitewash at the White House. 149 00:13:02,023 --> 00:13:05,151 ANNOUNCER 5:... series of record oil company profits were revealed... 150 00:13:05,360 --> 00:13:07,692 ANNOUNCER 6:... if the serious course of events continued. 151 00:13:07,895 --> 00:13:10,489 Foreign ministers are at this moment... 152 00:13:10,698 --> 00:13:11,824 Please stand by. 153 00:13:12,033 --> 00:13:13,466 Stand by. 154 00:13:18,039 --> 00:13:19,836 SAGAN: Then, suddenly... 155 00:13:20,041 --> 00:13:21,599 ...silence... 156 00:13:21,809 --> 00:13:25,745 ...total and absolute. 157 00:13:25,947 --> 00:13:29,110 But the dream was not yet done. 158 00:14:13,027 --> 00:14:14,824 Had we destroyed our home? 159 00:14:15,763 --> 00:14:18,561 What had we done to the Earth? 160 00:14:18,766 --> 00:14:21,860 There had been many ways for life to perish at our hands. 161 00:14:22,070 --> 00:14:24,436 We had poisoned the air and water. 162 00:14:24,639 --> 00:14:26,971 We had ravaged the land. 163 00:14:27,175 --> 00:14:28,938 Perhaps we had changed the climate. 164 00:14:29,844 --> 00:14:31,744 Could it have been a plague... 165 00:14:32,980 --> 00:14:34,845 ...or nuclear war? 166 00:14:42,523 --> 00:14:45,617 I remembered the galactic computer. 167 00:14:45,827 --> 00:14:48,159 What would it say about the Earth? 168 00:14:55,336 --> 00:14:57,736 There was our region of the galaxy. 169 00:15:05,346 --> 00:15:07,610 There was our world. 170 00:15:07,815 --> 00:15:10,841 I had found the entry for Earth. 171 00:15:12,220 --> 00:15:15,553 Humanity, third from the sun. 172 00:15:20,762 --> 00:15:23,060 They had heard our television broadcasts... 173 00:15:23,264 --> 00:15:27,030 ...and thought them an application for cosmic citizenship. 174 00:15:29,003 --> 00:15:31,096 Our technology had been growing enormously. 175 00:15:31,305 --> 00:15:32,829 They got that right. 176 00:15:35,510 --> 00:15:37,034 200 nation states. 177 00:15:37,245 --> 00:15:38,974 About six global powers. 178 00:15:39,180 --> 00:15:42,115 The potential to become one planet. 179 00:15:42,416 --> 00:15:46,182 Probability of survival over a century, here also... 180 00:15:46,387 --> 00:15:48,912 ...less than l% . 181 00:15:54,929 --> 00:15:57,193 So it was nuclear war. 182 00:15:57,398 --> 00:16:00,731 A full nuclear exchange. 183 00:16:00,935 --> 00:16:04,029 There would be no more big questions. 184 00:16:04,238 --> 00:16:06,229 No more answers. 185 00:16:06,440 --> 00:16:09,932 Never again a love or a child. 186 00:16:10,144 --> 00:16:13,511 No descendants to remember us and be proud. 187 00:16:13,714 --> 00:16:16,774 No more voyages to the stars. 188 00:16:16,984 --> 00:16:19,976 No more songs from the Earth. 189 00:16:24,992 --> 00:16:27,119 I saw East Africa... 190 00:16:27,328 --> 00:16:29,626 ...and thought a few million years ago... 191 00:16:29,831 --> 00:16:32,265 ...we humans took our first steps there. 192 00:16:32,466 --> 00:16:34,991 Our brains grew and changed. 193 00:16:35,203 --> 00:16:38,639 The old parts began to be guided by the new parts. 194 00:16:38,840 --> 00:16:39,966 And this made us human... 195 00:16:40,174 --> 00:16:44,406 ...with compassion and foresight and reason. 196 00:16:44,612 --> 00:16:49,208 But instead, we listened to that reptilian voice within us... 197 00:16:49,417 --> 00:16:52,944 ...counseling fear, territoriality... 198 00:16:53,154 --> 00:16:54,712 ...aggression. 199 00:16:54,922 --> 00:16:57,322 We accepted the products of science. 200 00:16:57,525 --> 00:16:59,857 We rejected its methods. 201 00:17:01,562 --> 00:17:04,827 Maybe the reptiles will evolve intelligence once more. 202 00:17:05,032 --> 00:17:09,662 Perhaps, one day, there will be civilizations again on Earth. 203 00:17:09,871 --> 00:17:11,202 There will be life. 204 00:17:11,405 --> 00:17:13,703 There will be intelligence. 205 00:17:13,908 --> 00:17:15,603 But there will be no more humans. 206 00:17:15,810 --> 00:17:20,008 Not here, not on a billion worlds. 207 00:17:43,070 --> 00:17:47,473 Every thinking person fears nuclear war... 208 00:17:47,675 --> 00:17:51,509 ...and every technological nation plans for it. 209 00:17:52,914 --> 00:17:55,474 Everyone knows it's madness... 210 00:17:55,683 --> 00:17:59,619 ...and every country has an excuse. 211 00:17:59,820 --> 00:18:04,757 There's a dreary chain of causality. 212 00:18:04,992 --> 00:18:07,961 The Germans were working on the bomb... 213 00:18:08,162 --> 00:18:10,062 ...at the beginning of World War II. 214 00:18:10,264 --> 00:18:13,324 So the Americans had to make one first. 215 00:18:13,534 --> 00:18:17,402 If the Americans had one, the Russians had to have one. 216 00:18:19,340 --> 00:18:22,036 Then, the British, the French... 217 00:18:22,243 --> 00:18:25,110 ...the Chinese, the Indians, the Pakistanis. 218 00:18:25,313 --> 00:18:28,874 Many nations now collect nuclear weapons. 219 00:18:29,083 --> 00:18:31,313 They're easy to make. 220 00:18:31,519 --> 00:18:36,218 You can steal fissionable material from nuclear reactors. 221 00:18:36,424 --> 00:18:41,361 Nuclear weapons have almost become a home handicraft industry. 222 00:18:42,263 --> 00:18:46,563 The conventional bombs of World War II were called "blockbusters." 223 00:18:46,767 --> 00:18:51,500 Filled with 20 tons of TNT, they could destroy a city block. 224 00:18:51,706 --> 00:18:55,198 All the bombs dropped on all the cities of World War II... 225 00:18:55,409 --> 00:18:57,934 ...amounted to some 2 million tons of TNT. 226 00:18:58,145 --> 00:18:59,772 Two megatons. 227 00:18:59,981 --> 00:19:02,245 Coventry and Rotterdam. 228 00:19:02,450 --> 00:19:03,940 Dresden and Tokyo. 229 00:19:04,151 --> 00:19:06,483 All the death that rained from the skies... 230 00:19:06,687 --> 00:19:09,679 ...between 1939 and 1945. 231 00:19:09,890 --> 00:19:14,759 100,000 blockbusters. Two megatons. 232 00:19:14,962 --> 00:19:19,456 Today, two megatons is the equivalent of a single thermonuclear bomb. 233 00:19:19,667 --> 00:19:22,659 One bomb with the destructive force... 234 00:19:22,870 --> 00:19:25,498 ...of the Second World War. 235 00:19:25,706 --> 00:19:28,231 But there are tens of thousands of nuclear weapons. 236 00:19:28,442 --> 00:19:31,468 The missile and bomber forces of the Soviet Union and U. S... 237 00:19:31,679 --> 00:19:36,116 ...have warheads aimed at over 15,000 designated targets. 238 00:19:36,317 --> 00:19:39,115 No place on the planet is safe. 239 00:19:39,320 --> 00:19:41,982 The energy contained in these weapons... 240 00:19:42,189 --> 00:19:43,918 ...genies of death... 241 00:19:44,125 --> 00:19:48,528 ...patiently awaiting the rubbing of the lamps... 242 00:19:48,729 --> 00:19:51,357 ...totals far more than 10,000 megatons. 243 00:19:51,565 --> 00:19:55,160 But with the destruction concentrated efficiently... 244 00:19:55,369 --> 00:19:58,600 ...not over six years, but over a few hours. 245 00:19:58,806 --> 00:20:02,742 A blockbuster for every family on the planet. 246 00:20:02,943 --> 00:20:05,810 A World War II every second... 247 00:20:06,013 --> 00:20:09,574 ...for the length of a lazy afternoon. 248 00:20:11,152 --> 00:20:13,017 (BIRDS CHIRPING) 249 00:20:15,489 --> 00:20:17,150 The bomb dropped on Hiroshima... 250 00:20:17,358 --> 00:20:19,883 ...killed 70,000 people. 251 00:20:20,094 --> 00:20:22,289 In a full nuclear exchange... 252 00:20:22,496 --> 00:20:25,158 ...in the paroxysm of global death... 253 00:20:25,366 --> 00:20:28,199 ...the equivalent of a million Hiroshima bombs... 254 00:20:28,402 --> 00:20:31,166 ...would be dropped all over the world. 255 00:20:31,372 --> 00:20:33,397 In such an exchange not everyone would be... 256 00:20:33,607 --> 00:20:37,668 ...killed by the blast and firestorm and the immediate radiation. 257 00:20:37,878 --> 00:20:40,506 There would be other agonies: 258 00:20:40,714 --> 00:20:41,703 Loss of loved ones... 259 00:20:41,916 --> 00:20:46,319 ...the legions of the burned and blinded and mutilated... 260 00:20:46,520 --> 00:20:48,215 ...the absence of medical care... 261 00:20:48,422 --> 00:20:49,753 ...disease, plague... 262 00:20:49,957 --> 00:20:54,018 ...long-lived radiation poisoning of the soil and the water. 263 00:20:54,228 --> 00:20:59,097 The threat of tumors and stillbirths and malformed children. 264 00:20:59,300 --> 00:21:02,861 And the hopeless sense of a civilization destroyed for nothing. 265 00:21:03,070 --> 00:21:07,166 The knowledge that we could have prevented it and did not. 266 00:21:10,044 --> 00:21:13,411 The global balance of terror... 267 00:21:13,614 --> 00:21:16,378 ...pioneered by the U.S. and the Soviet Union... 268 00:21:16,584 --> 00:21:20,020 ...holds hostage all the citizens of the Earth. 269 00:21:20,221 --> 00:21:22,815 Each side persistently probes... 270 00:21:23,023 --> 00:21:25,423 ...the limits of the other's tolerance... 271 00:21:25,626 --> 00:21:29,357 ...like the Cuban missile crisis... 272 00:21:29,864 --> 00:21:32,128 ...the testing of anti-satellite weapons... 273 00:21:32,333 --> 00:21:34,824 ...the Vietnam and Afghanistan wars. 274 00:21:35,035 --> 00:21:37,003 The hostile military establishments are... 275 00:21:37,204 --> 00:21:41,004 ...locked in some ghastly mutual embrace. 276 00:21:41,208 --> 00:21:42,937 Each needs the other. 277 00:21:43,144 --> 00:21:46,875 But the balance of terror is a delicate balance... 278 00:21:47,081 --> 00:21:50,608 ...with very little margin for miscalculation. 279 00:21:52,186 --> 00:21:55,986 And the world impoverishes itself by spending... 280 00:21:56,690 --> 00:22:01,127 ...a trillion dollars a year on preparations for war. 281 00:22:01,328 --> 00:22:02,920 And by employing perhaps... 282 00:22:03,130 --> 00:22:06,190 ...half the scientists and high technologists on the planet... 283 00:22:06,400 --> 00:22:08,527 ...in military endeavors. 284 00:22:10,738 --> 00:22:12,433 How would we explain all this... 285 00:22:12,640 --> 00:22:15,006 ...to a dispassionate extraterrestrial observer? 286 00:22:15,209 --> 00:22:19,043 What account would we give of our stewardship... 287 00:22:19,246 --> 00:22:20,713 ...of the planet Earth? 288 00:22:20,915 --> 00:22:24,373 We have heard the rationales offered by the superpowers. 289 00:22:24,585 --> 00:22:27,213 We know who speaks for the nations. 290 00:22:27,421 --> 00:22:29,889 But who speaks for the human species? 291 00:22:30,090 --> 00:22:32,149 Who speaks for Earth? 292 00:22:33,327 --> 00:22:37,525 From an extraterrestrial perspective, our global civilization is... 293 00:22:37,731 --> 00:22:40,165 ...clearly on the edge of failure... 294 00:22:40,367 --> 00:22:42,267 ...in the most important task it faces: 295 00:22:42,469 --> 00:22:45,905 Preserving the lives and well-being of its citizens... 296 00:22:46,106 --> 00:22:49,269 ...and the future habitability of the planet. 297 00:22:49,476 --> 00:22:53,913 But if we're willing to live with the growing likelihood of nuclear war... 298 00:22:54,114 --> 00:22:57,277 ...shouldn't we also be willing to explore vigorously... 299 00:22:57,484 --> 00:23:00,112 ...every possible means to prevent nuclear war? 300 00:23:00,321 --> 00:23:03,017 Shouldn't we consider, in every nation... 301 00:23:03,224 --> 00:23:06,284 ...major changes in the traditional ways of doing things? 302 00:23:06,493 --> 00:23:08,290 A fundamental restructuring... 303 00:23:08,495 --> 00:23:12,124 ...of economic, political, social and religious institutions? 304 00:23:12,633 --> 00:23:15,466 We've reached a point where there can be no more... 305 00:23:15,669 --> 00:23:17,569 ...special interests or cases. 306 00:23:17,905 --> 00:23:21,432 Nuclear arms threaten every person on Earth. 307 00:23:22,810 --> 00:23:27,213 Fundamental changes in society are sometimes labeled... 308 00:23:27,414 --> 00:23:31,612 ...impractical or contrary to human nature... 309 00:23:31,819 --> 00:23:34,117 ...as if nuclear war were practical... 310 00:23:34,321 --> 00:23:37,313 ...or as if there were only one human nature. 311 00:23:37,925 --> 00:23:40,519 But fundamental changes can clearly be made. 312 00:23:40,728 --> 00:23:42,696 We're surrounded by them. 313 00:23:42,896 --> 00:23:45,558 In the last two centuries, abject slavery... 314 00:23:45,766 --> 00:23:48,326 ...which was with us for thousands of years... 315 00:23:48,535 --> 00:23:50,628 ...has almost entirely been eliminated... 316 00:23:50,838 --> 00:23:53,432 ...in a stirring worldwide revolution. 317 00:23:53,641 --> 00:23:57,236 Women, systematically mistreated for millennia... 318 00:23:57,444 --> 00:24:00,345 ...are gradually gaining the political and economic power... 319 00:24:00,547 --> 00:24:02,811 ...traditionally denied to them. 320 00:24:03,017 --> 00:24:07,613 And some wars of aggression have recently been stopped or curtailed... 321 00:24:07,821 --> 00:24:10,051 ...because of a revulsion... 322 00:24:10,257 --> 00:24:13,420 ...felt by the people in the aggressor nations. 323 00:24:13,627 --> 00:24:15,754 The old appeals... 324 00:24:15,963 --> 00:24:18,864 ...to racial, sexual, and religious chauvinism... 325 00:24:19,066 --> 00:24:22,331 ...and to rabid nationalist fervor... 326 00:24:22,536 --> 00:24:24,367 ...are beginning not to work. 327 00:24:24,571 --> 00:24:28,234 A new consciousness is developing which sees the Earth as... 328 00:24:28,442 --> 00:24:29,966 ...a single organism... 329 00:24:30,177 --> 00:24:34,307 ...and recognizes that an organism at war with itself... 330 00:24:34,515 --> 00:24:35,948 ...is doomed. 331 00:24:36,150 --> 00:24:38,880 We are one planet. 332 00:24:40,888 --> 00:24:44,517 One of the great revelations of the age of space exploration... 333 00:24:44,725 --> 00:24:47,853 ...is the image of the Earth, finite and lonely... 334 00:24:48,062 --> 00:24:52,931 ...somehow vulnerable, bearing the entire human species... 335 00:24:53,133 --> 00:24:56,864 ...through the oceans of space and time. 336 00:24:57,071 --> 00:24:59,437 But this is an ancient perception. 337 00:24:59,640 --> 00:25:01,403 In the 3rd century B. C... 338 00:25:01,608 --> 00:25:04,099 ...our planet was mapped and accurately measured... 339 00:25:04,311 --> 00:25:08,441 ...by a Greek scientist named Eratosthenes, who worked in Egypt. 340 00:25:08,649 --> 00:25:11,243 This was the world as he knew it. 341 00:25:12,019 --> 00:25:14,351 Eratosthenes was the director... 342 00:25:14,555 --> 00:25:17,251 ...of the great Library of Alexandria... 343 00:25:17,458 --> 00:25:21,724 ...the center of science and learning in the ancient world. 344 00:25:22,963 --> 00:25:27,024 Aristotle had argued that humanity was divided into Greeks... 345 00:25:27,234 --> 00:25:31,136 ...and everybody else, who he called "barbarians"... 346 00:25:31,338 --> 00:25:35,365 ...and that the Greeks should keep themselves racially pure. 347 00:25:35,576 --> 00:25:39,945 He taught that it was fitting for the Greeks to enslave other peoples. 348 00:25:40,147 --> 00:25:44,914 But Eratosthenes criticized Aristotle for his blind chauvinism. 349 00:25:45,119 --> 00:25:49,283 He believed there was good and bad in every nation. 350 00:25:49,490 --> 00:25:53,790 The Greek conquerors had invented a new god for the Egyptians... 351 00:25:53,994 --> 00:25:57,191 ...but he looked remarkably Greek. 352 00:25:57,398 --> 00:25:59,923 Alexander was portrayed as pharaoh... 353 00:26:00,134 --> 00:26:02,398 ...in a gesture to the Egyptians. 354 00:26:02,603 --> 00:26:07,097 But in practice, the Greeks were confident of their superiority. 355 00:26:08,108 --> 00:26:12,101 The protests of the librarian hardly constituted a serious challenge... 356 00:26:12,312 --> 00:26:14,109 ...to prevailing prejudices. 357 00:26:14,314 --> 00:26:17,181 Their world was as imperfect as our own. 358 00:26:17,384 --> 00:26:20,979 But the Ptolemies, the Greek kings of Egypt who followed Alexander... 359 00:26:21,188 --> 00:26:23,053 ...had at least this virtue: 360 00:26:23,257 --> 00:26:26,420 They supported the advancement of knowledge. 361 00:26:26,627 --> 00:26:29,960 Popular ideas about the nature of the cosmos were challenged... 362 00:26:30,164 --> 00:26:32,064 ...and some of them, discarded. 363 00:26:32,266 --> 00:26:33,824 New ideas were proposed... 364 00:26:34,034 --> 00:26:36,502 ...and found to be in better accord with the facts. 365 00:26:36,703 --> 00:26:39,570 There were imaginative proposals, vigorous debates... 366 00:26:39,773 --> 00:26:41,138 ...brilliant syntheses. 367 00:26:41,341 --> 00:26:43,309 The resulting treasure of knowledge... 368 00:26:43,510 --> 00:26:46,411 ...was recorded and preserved for centuries... 369 00:26:46,613 --> 00:26:49,081 ...on these shelves. 370 00:26:50,451 --> 00:26:54,319 Science came of age in this library. 371 00:26:56,924 --> 00:27:01,054 The Ptolemies didn't merely collect old knowledge. 372 00:27:01,261 --> 00:27:04,958 They supported scientific research and generated new knowledge. 373 00:27:05,165 --> 00:27:06,962 The results were amazing. 374 00:27:07,167 --> 00:27:11,570 Eratosthenes accurately calculated the size of the Earth. 375 00:27:11,772 --> 00:27:12,864 He mapped it... 376 00:27:13,073 --> 00:27:16,270 ...and he argued that it could be circumnavigated. 377 00:27:16,477 --> 00:27:20,504 Hipparchus anticipated that stars come into being... 378 00:27:20,714 --> 00:27:23,274 ...slowly move during the course of centuries... 379 00:27:23,484 --> 00:27:24,815 ...and eventually perish. 380 00:27:25,018 --> 00:27:27,009 It was he who first catalogued... 381 00:27:27,221 --> 00:27:29,951 ...the positions and magnitudes of the stars... 382 00:27:30,257 --> 00:27:33,420 ...in order to determine whether there were such changes. 383 00:27:33,627 --> 00:27:36,425 Euclid produced a textbook on geometry... 384 00:27:36,630 --> 00:27:39,793 ...which human beings learned from for 23 centuries. 385 00:27:40,000 --> 00:27:44,733 It's still a great read, full of the most elegant proofs. 386 00:27:44,938 --> 00:27:48,533 Galen wrote basic works on healing and anatomy... 387 00:27:48,742 --> 00:27:51,472 ...which dominated medicine until the Renaissance. 388 00:27:51,678 --> 00:27:53,339 These are just a few examples. 389 00:27:53,547 --> 00:27:55,879 There were dozens of great scholars here... 390 00:27:56,083 --> 00:27:59,849 ...and hundreds of fundamental discoveries. 391 00:28:04,191 --> 00:28:07,592 Some of those discoveries have a distinctly modern ring. 392 00:28:07,794 --> 00:28:11,730 Apollonius of Perga studied the parabola and the ellipse... 393 00:28:11,932 --> 00:28:15,698 ...curves that we know today describe the paths of falling objects... 394 00:28:15,903 --> 00:28:17,268 ...in a gravitational field... 395 00:28:17,471 --> 00:28:20,702 ...and space vehicles traveling between the planets. 396 00:28:20,908 --> 00:28:25,345 Heron of Alexandria invented steam engines and gear trains... 397 00:28:25,546 --> 00:28:29,380 ...he was the author of the first book on robots. 398 00:28:29,583 --> 00:28:32,916 Imagine how different our world would be if those discoveries... 399 00:28:33,120 --> 00:28:35,850 ...had been used for the benefit of everyone. 400 00:28:36,056 --> 00:28:38,923 If the humane perspective of Eratosthenes... 401 00:28:39,126 --> 00:28:41,390 ...had been widely adopted and applied. 402 00:28:41,595 --> 00:28:44,496 But this was not to be. 403 00:28:46,366 --> 00:28:49,563 Alexandria was the greatest city... 404 00:28:49,770 --> 00:28:52,864 ...the Western world had ever seen. 405 00:28:53,073 --> 00:28:55,041 People from all nations came here... 406 00:28:55,242 --> 00:28:57,437 ...to live, to trade, to learn. 407 00:28:57,644 --> 00:28:59,168 On a given day... 408 00:28:59,379 --> 00:29:02,371 ...these harbors were thronged... 409 00:29:02,583 --> 00:29:06,041 ...with merchants and scholars, tourists. 410 00:29:06,253 --> 00:29:07,447 It's probably here... 411 00:29:07,654 --> 00:29:11,181 ...that the word "cosmopolitan" realized its true meaning... 412 00:29:11,391 --> 00:29:14,656 ...of a citizen, not just of a nation... 413 00:29:14,861 --> 00:29:16,795 ...but of the cosmos. 414 00:29:16,997 --> 00:29:21,934 To be a citizen of the cosmos. 415 00:29:22,636 --> 00:29:26,766 Here were clearly the seeds of our modern world. 416 00:29:26,974 --> 00:29:29,943 But why didn't they take root and flourish? 417 00:29:30,143 --> 00:29:34,512 Why, instead, did the West slumber through 1000 years of darkness... 418 00:29:34,715 --> 00:29:38,481 ...until Columbus and Copernicus and their contemporaries... 419 00:29:38,685 --> 00:29:42,086 ...rediscovered the work done here? 420 00:29:42,289 --> 00:29:44,519 I cannot give you a simple answer... 421 00:29:44,725 --> 00:29:46,590 ...but I do know this: 422 00:29:46,793 --> 00:29:50,627 There is no record in the entire history of the library... 423 00:29:50,831 --> 00:29:54,767 ...that any of the illustrious scholars and scientists who worked here... 424 00:29:54,968 --> 00:29:57,300 ...ever seriously challenged... 425 00:29:57,504 --> 00:30:01,736 ...a single political or economic or religious assumption... 426 00:30:01,942 --> 00:30:04,240 ...of the society in which they lived. 427 00:30:04,444 --> 00:30:08,403 The permanence of the stars was questioned. 428 00:30:08,615 --> 00:30:12,483 The justice of slavery was not. 429 00:30:27,934 --> 00:30:31,165 Science and learning in general... 430 00:30:31,371 --> 00:30:33,999 ...were the preserve of the privileged few. 431 00:30:34,207 --> 00:30:38,337 The vast population of this city had not the vaguest notion... 432 00:30:38,545 --> 00:30:42,311 ...of the great discoveries being made within these walls. 433 00:30:42,516 --> 00:30:43,915 How could they? 434 00:30:44,117 --> 00:30:47,848 The new findings were not explained or popularized. 435 00:30:48,055 --> 00:30:51,456 The progress made here benefited them little. 436 00:30:51,658 --> 00:30:54,183 Science was not part of their lives. 437 00:30:54,394 --> 00:30:57,386 The discoveries in mechanics, say... 438 00:30:57,597 --> 00:30:59,428 ...or steam technology... 439 00:30:59,633 --> 00:31:03,535 ...mainly were applied to the perfection of weapons... 440 00:31:03,737 --> 00:31:06,035 ...to the encouragement of superstition... 441 00:31:06,239 --> 00:31:08,207 ...to the amusement of kings. 442 00:31:08,408 --> 00:31:12,276 Scientists never seemed to grasp the enormous potential... 443 00:31:12,479 --> 00:31:15,414 ...of machines to free people... 444 00:31:15,615 --> 00:31:19,244 ...from arduous and repetitive labor. 445 00:31:19,453 --> 00:31:21,614 The intellectual achievements of antiquity... 446 00:31:21,822 --> 00:31:24,484 ...had few practical applications. 447 00:31:24,691 --> 00:31:29,628 Science never captured the imagination of the multitude. 448 00:31:30,130 --> 00:31:33,657 There was no counterbalance to stagnation, to pessimism... 449 00:31:33,867 --> 00:31:38,270 ...to the most abject surrender to mysticism. 450 00:31:38,472 --> 00:31:41,635 So when, at long last... 451 00:31:41,842 --> 00:31:44,675 ...the mob came to burn the place down... 452 00:31:44,878 --> 00:31:47,278 ...there was nobody to stop them. 453 00:32:09,169 --> 00:32:12,195 Let me tell you about the end. 454 00:32:12,405 --> 00:32:16,671 It's a story about the last scientist to work in this place. 455 00:32:16,877 --> 00:32:20,108 A mathematician, astronomer, physicist... 456 00:32:20,313 --> 00:32:25,148 ...and head of the school of Neo- Platonic philosophy in Alexandria. 457 00:32:25,352 --> 00:32:27,582 That's an extraordinary range of accomplishments... 458 00:32:27,788 --> 00:32:30,382 ...for any individual, in any age. 459 00:32:30,590 --> 00:32:33,354 Her name was Hypatia. 460 00:32:33,560 --> 00:32:38,156 She was born in this city in the year 370 A.D. 461 00:32:40,667 --> 00:32:44,398 This was a time when women had essentially no options. 462 00:32:44,604 --> 00:32:46,936 They were considered property. 463 00:32:47,140 --> 00:32:50,837 Nevertheless, Hypatia was able to move freely... 464 00:32:51,044 --> 00:32:52,705 ...unselfconsciously... 465 00:32:52,913 --> 00:32:56,371 ...through traditional male domains. 466 00:32:56,583 --> 00:32:59,882 By all accounts, she was a great beauty. 467 00:33:00,086 --> 00:33:01,713 And although she had many suitors... 468 00:33:01,922 --> 00:33:04,823 ...she had no interest in marriage. 469 00:33:06,092 --> 00:33:11,029 The Alexandria of Hypatia's time, by then long under Roman rule... 470 00:33:11,398 --> 00:33:14,333 ...was a city in grave conflict. 471 00:33:14,534 --> 00:33:18,061 Slavery, the cancer of the ancient world... 472 00:33:18,271 --> 00:33:22,605 ...had sapped classical civilization of its vitality. 473 00:33:22,809 --> 00:33:25,243 The growing Christian Church was... 474 00:33:25,445 --> 00:33:27,345 ...consolidating its power... 475 00:33:27,547 --> 00:33:32,075 ...and attempting to eradicate pagan influence and culture. 476 00:33:32,285 --> 00:33:36,654 Hypatia stood at the focus... 477 00:33:36,857 --> 00:33:41,692 ...at the epicenter of mighty social forces. 478 00:33:41,895 --> 00:33:45,626 Cyril, the Bishop of Alexandria, despised her... 479 00:33:45,832 --> 00:33:49,962 ...in part because of her close friendship with a Roman governor... 480 00:33:50,170 --> 00:33:54,300 ...but also because she was a symbol of learning and science... 481 00:33:54,507 --> 00:33:58,944 ...which were largely identified by the early Church with paganism. 482 00:33:59,946 --> 00:34:01,675 In great personal danger... 483 00:34:01,882 --> 00:34:05,613 ...Hypatia continued to teach and to publish... 484 00:34:05,819 --> 00:34:10,449 ...until, in the year 415 A.D., on her way to work... 485 00:34:10,657 --> 00:34:12,784 ...she was set upon... 486 00:34:12,993 --> 00:34:16,360 ...by a fanatical mob of Cyril's followers. 487 00:34:16,563 --> 00:34:19,225 They dragged her from her chariot... 488 00:34:19,432 --> 00:34:21,059 ...tore off her clothes... 489 00:34:21,268 --> 00:34:25,102 ...and flayed her flesh from her bones... 490 00:34:25,305 --> 00:34:27,671 ...with abalone shells. 491 00:34:27,874 --> 00:34:31,401 Her remains were burned, her works obliterated... 492 00:34:31,611 --> 00:34:33,135 ...her name forgotten. 493 00:34:33,346 --> 00:34:36,509 Cyril was made a saint. 494 00:34:39,019 --> 00:34:42,978 The glory you see around me... 495 00:34:43,189 --> 00:34:46,022 ...is nothing but a memory. 496 00:34:46,226 --> 00:34:47,716 It does not exist. 497 00:34:49,462 --> 00:34:52,431 The last remains of the library were destroyed... 498 00:34:52,632 --> 00:34:55,157 ...within a year of Hypatia's death. 499 00:34:55,368 --> 00:34:59,031 It's as if an entire civilization had undergone... 500 00:34:59,239 --> 00:35:03,369 ...a sort of self-inflicted radical brain surgery... 501 00:35:03,743 --> 00:35:06,007 ...so that most of its memories... 502 00:35:06,212 --> 00:35:09,375 ...discoveries, ideas and passions... 503 00:35:09,582 --> 00:35:12,983 ...were irrevocably wiped out. 504 00:35:15,522 --> 00:35:18,650 The loss was incalculable. 505 00:35:18,892 --> 00:35:21,190 In some cases, we know only... 506 00:35:21,394 --> 00:35:25,023 ...the tantalizing titles of books that had been destroyed. 507 00:35:25,265 --> 00:35:29,998 In most cases, we know neither the titles nor the authors. 508 00:35:30,203 --> 00:35:32,637 We do know that in this library... 509 00:35:32,839 --> 00:35:36,866 ...there were 123 different plays by Sophocles... 510 00:35:37,077 --> 00:35:40,137 ...of which only seven have survived to our time. 511 00:35:40,347 --> 00:35:43,145 One of those seven is Oedipus Rex. 512 00:35:43,350 --> 00:35:46,217 Similar numbers apply to the lost works of... 513 00:35:46,419 --> 00:35:49,911 ...Aeschylus, Euripides, Aristophanes. 514 00:35:50,123 --> 00:35:53,786 It's a little as if the only surviving works of a man named... 515 00:35:53,994 --> 00:35:55,928 ...William Shakespeare... 516 00:35:56,129 --> 00:36:00,088 ...were Coriolanus and A Winter's Tale... 517 00:36:00,300 --> 00:36:03,292 ...although we knew he had written some other things... 518 00:36:03,503 --> 00:36:05,596 ...which were highly prized in his time. 519 00:36:05,805 --> 00:36:09,263 Plays called Hamlet, Macbeth... 520 00:36:09,476 --> 00:36:13,037 ...A Midsummer's Night Dream, Julius Caesar, King Lear... 521 00:36:13,246 --> 00:36:15,077 ...Romeo and Juliet. 522 00:36:22,222 --> 00:36:25,282 History is full of people... 523 00:36:25,492 --> 00:36:29,451 ...who, out of fear or ignorance... 524 00:36:29,662 --> 00:36:31,095 ...or the lust for power... 525 00:36:31,297 --> 00:36:35,256 ...have destroyed treasures of immeasurable value... 526 00:36:35,468 --> 00:36:39,063 ...which truly belong to all of us. 527 00:36:39,272 --> 00:36:43,106 We must not let it happen again. 528 00:37:03,963 --> 00:37:06,454 We have considered the destruction of worlds... 529 00:37:06,666 --> 00:37:09,191 ...and the end of civilizations. 530 00:37:09,402 --> 00:37:13,099 But there is another perspective by which to measure human endeavors. 531 00:37:13,306 --> 00:37:17,003 Let me tell you a story about the beginning. 532 00:37:17,510 --> 00:37:19,705 Some 15 billion years ago... 533 00:37:19,913 --> 00:37:21,437 ...our universe began... 534 00:37:21,648 --> 00:37:25,015 ...with the mightiest explosion of all time. 535 00:37:25,218 --> 00:37:28,779 The universe expanded, cooled and darkened. 536 00:37:28,988 --> 00:37:32,287 Energy condensed into matter, mostly hydrogen atoms. 537 00:37:32,492 --> 00:37:35,950 And these atoms accumulated into vast clouds... 538 00:37:36,162 --> 00:37:37,789 ...rushing away from each other... 539 00:37:37,997 --> 00:37:41,228 ...that would one day become the galaxies. 540 00:37:42,268 --> 00:37:46,466 Within these galaxies the first generation of stars was born... 541 00:37:46,673 --> 00:37:49,073 ...kindling the energy hidden in matter... 542 00:37:49,275 --> 00:37:52,005 ...flooding the cosmos with light. 543 00:37:52,212 --> 00:37:57,149 Hydrogen atoms had made suns and starlight. 544 00:37:59,052 --> 00:38:02,647 There were in those times no planets to receive the light... 545 00:38:02,856 --> 00:38:06,986 ...and no living creatures to admire the radiance of the heavens. 546 00:38:07,193 --> 00:38:09,093 But deep in the stellar furnaces... 547 00:38:09,295 --> 00:38:12,321 ...nuclear fusion was creating the heavier atoms: 548 00:38:12,532 --> 00:38:15,501 Carbon and oxygen, silicon and iron. 549 00:38:15,702 --> 00:38:18,933 These elements, the ash left by hydrogen... 550 00:38:19,139 --> 00:38:24,076 ...were the raw materials from which planets and life would later arise. 551 00:38:24,277 --> 00:38:28,213 At first, the heavy elements were trapped in the hearts of the stars. 552 00:38:28,414 --> 00:38:31,508 But massive stars soon exhausted their fuel... 553 00:38:31,718 --> 00:38:33,208 ...and in their death throes... 554 00:38:33,419 --> 00:38:36,445 ...returned most of their substance back into space. 555 00:38:36,656 --> 00:38:41,025 The interstellar gas became enriched in heavy elements. 556 00:38:42,695 --> 00:38:44,128 In the Milky Way galaxy... 557 00:38:44,330 --> 00:38:48,289 ...the matter of the cosmos was recycled into new generations of stars... 558 00:38:48,501 --> 00:38:50,469 ...now rich in heavy atoms. 559 00:38:50,670 --> 00:38:54,367 A legacy from their stellar ancestors. 560 00:38:56,075 --> 00:38:58,270 And in the cold of interstellar space... 561 00:38:58,478 --> 00:39:01,970 ...great turbulent clouds were gathered by gravity... 562 00:39:02,182 --> 00:39:05,015 ...and stirred by starlight. 563 00:39:08,922 --> 00:39:10,014 In their depths... 564 00:39:10,223 --> 00:39:13,852 ...the heavy atoms condensed into grains of rocky dust and ice... 565 00:39:14,060 --> 00:39:17,120 ...and complex carbon-based molecules. 566 00:39:17,330 --> 00:39:20,390 In accordance with the laws of physics and chemistry... 567 00:39:20,600 --> 00:39:25,469 ...hydrogen atoms had brought forth the stuff of life. 568 00:39:32,879 --> 00:39:36,246 In other clouds, more massive aggregates of gas and dust... 569 00:39:36,449 --> 00:39:38,917 ...formed later generations of stars. 570 00:39:39,118 --> 00:39:40,847 As new stars were formed... 571 00:39:41,054 --> 00:39:43,989 ...tiny condensations of matter accreted near them... 572 00:39:44,190 --> 00:39:47,887 ...inconspicuous motes of rock and metal, ice and gas... 573 00:39:48,094 --> 00:39:49,959 ...that would become the planets. 574 00:39:50,163 --> 00:39:53,132 And on these worlds, as in interstellar clouds... 575 00:39:53,333 --> 00:39:55,164 ...organic molecules formed... 576 00:39:55,368 --> 00:39:59,031 ...made of atoms that had been cooked inside the stars. 577 00:39:59,239 --> 00:40:02,299 In the tide pools and oceans of many worlds... 578 00:40:02,508 --> 00:40:06,774 ...molecules were destroyed by sunlight and assembled by chemistry. 579 00:40:06,980 --> 00:40:10,143 One day, among these natural experiments... 580 00:40:10,350 --> 00:40:13,148 ...a molecule arose, that, quite by accident... 581 00:40:13,353 --> 00:40:16,413 ...was able to make crude copies of itself. 582 00:40:22,028 --> 00:40:25,486 As time passed, self-replication became more accurate. 583 00:40:25,698 --> 00:40:27,495 Those molecules that copied better... 584 00:40:27,700 --> 00:40:29,258 ...produced more copies. 585 00:40:29,469 --> 00:40:31,960 Natural selection was underway. 586 00:40:32,171 --> 00:40:35,197 Elaborate molecular machines had evolved. 587 00:40:35,408 --> 00:40:39,674 Slowly, imperceptibly, life had begun. 588 00:40:46,586 --> 00:40:50,852 Collectives of organic molecules evolved into one-celled organisms. 589 00:40:51,057 --> 00:40:53,582 These produced multi-celled colonies. 590 00:40:53,793 --> 00:40:57,160 Their various parts became specialized organs. 591 00:40:57,363 --> 00:41:00,764 Some colonies attached themselves to the sea floor... 592 00:41:00,967 --> 00:41:03,765 ...others swam freely. 593 00:41:04,937 --> 00:41:07,997 Eyes evolved, and now the cosmos could see. 594 00:41:08,207 --> 00:41:11,370 Living things moved on to colonize the land. 595 00:41:11,577 --> 00:41:14,205 The reptiles held sway for a time... 596 00:41:14,414 --> 00:41:18,441 ...but gave way to small warm-blooded creatures with bigger brains... 597 00:41:18,651 --> 00:41:22,781 ...who developed dexterity and curiosity about their environment. 598 00:41:22,989 --> 00:41:26,356 They learned to use tools and fire and language. 599 00:41:26,559 --> 00:41:29,255 Star stuff, the ash of stellar alchemy... 600 00:41:29,462 --> 00:41:32,397 ...had emerged into consciousness. 601 00:41:42,975 --> 00:41:47,275 We are a way for the cosmos to know itself. 602 00:41:47,480 --> 00:41:49,471 We are creatures of the cosmos... 603 00:41:49,682 --> 00:41:52,981 ...and have always hungered to know our origins... 604 00:41:53,186 --> 00:41:56,815 ...to understand our connection with the universe. 605 00:41:57,023 --> 00:41:59,548 How did everything come to be? 606 00:42:01,160 --> 00:42:04,061 Every culture on the planet has devised its own response... 607 00:42:04,263 --> 00:42:07,232 ...to the riddle posed by the universe. 608 00:42:11,304 --> 00:42:15,934 Every culture celebrates the cycles of life and nature. 609 00:42:17,543 --> 00:42:19,977 There are many different ways of being human. 610 00:42:24,217 --> 00:42:26,242 But an extraterrestrial visitor... 611 00:42:26,452 --> 00:42:29,216 ...examining the differences among human societies... 612 00:42:29,422 --> 00:42:31,856 ...would find those differences trivial... 613 00:42:32,058 --> 00:42:34,390 ...compared to the similarities. 614 00:42:42,034 --> 00:42:44,935 We are one species. 615 00:43:04,657 --> 00:43:08,252 We are star stuff, harvesting starlight. 616 00:43:08,661 --> 00:43:11,596 Our lives, our past and our future... 617 00:43:11,798 --> 00:43:16,292 ...are tied to the sun, the moon and the stars. 618 00:43:19,772 --> 00:43:22,832 Our ancestors knew that their survival depended... 619 00:43:23,042 --> 00:43:24,737 ...on understanding the heavens. 620 00:43:24,944 --> 00:43:27,538 They built observatories and computers... 621 00:43:27,747 --> 00:43:32,275 ...to predict the changing of the seasons by the motions in the skies. 622 00:43:32,485 --> 00:43:34,646 We are, all of us... 623 00:43:34,854 --> 00:43:38,051 ...descended from astronomers. 624 00:43:40,226 --> 00:43:42,421 The discovery of order in the universe... 625 00:43:42,628 --> 00:43:44,118 ...of the laws of nature... 626 00:43:44,330 --> 00:43:48,494 ...is the foundation on which science builds today. 627 00:43:55,608 --> 00:43:57,200 Our conception of the cosmos... 628 00:43:57,410 --> 00:43:59,435 ...all of modern science and technology... 629 00:43:59,645 --> 00:44:03,638 ...trace back to questions raised by the stars. 630 00:44:05,284 --> 00:44:07,445 Yet, even 400 years ago... 631 00:44:07,653 --> 00:44:10,486 ...we still had no idea of our place in the universe. 632 00:44:10,690 --> 00:44:13,056 The long journey to that understanding... 633 00:44:13,259 --> 00:44:16,092 ...required both an unflinching respect for the facts... 634 00:44:16,295 --> 00:44:19,059 ...and a delight in the natural world. 635 00:44:21,834 --> 00:44:23,768 Johannes Kepler wrote: 636 00:44:23,970 --> 00:44:27,770 "We do not ask for what useful purpose the birds do sing... 637 00:44:27,974 --> 00:44:32,035 ...for song is their pleasure since they were created for singing. 638 00:44:32,378 --> 00:44:33,402 Similarly... 639 00:44:33,613 --> 00:44:36,582 ...we ought not to ask why the human mind troubles to fathom... 640 00:44:36,782 --> 00:44:38,272 ...the secrets of the heavens. 641 00:44:38,484 --> 00:44:41,715 The diversity of the phenomena of nature is so great... 642 00:44:41,921 --> 00:44:45,186 ...and the treasures hidden in the heavens so rich... 643 00:44:45,391 --> 00:44:46,824 ...precisely in order... 644 00:44:47,026 --> 00:44:51,224 ...that the human mind shall never be lacking in fresh nourishment." 645 00:45:32,705 --> 00:45:34,832 It is the birthright of every child... 646 00:45:35,041 --> 00:45:37,339 ...to encounter the cosmos anew... 647 00:45:37,543 --> 00:45:40,171 ...in every culture and every age. 648 00:45:42,682 --> 00:45:47,312 When this happens to us, we experience a deep sense of wonder. 649 00:45:47,520 --> 00:45:50,387 The most fortunate among us are guided by teachers... 650 00:45:50,590 --> 00:45:53,491 ...who channel this exhilaration. 651 00:45:55,962 --> 00:45:58,487 We are born to delight in the world. 652 00:45:58,698 --> 00:46:03,101 We are taught to distinguish our preconceptions from the truth. 653 00:46:03,302 --> 00:46:06,362 Then, new worlds are discovered... 654 00:46:06,572 --> 00:46:10,474 ...as we decipher the mysteries of the cosmos. 655 00:46:28,094 --> 00:46:30,562 Science is a collective enterprise... 656 00:46:30,763 --> 00:46:34,529 ...that embraces many cultures and spans the generations. 657 00:46:34,734 --> 00:46:38,465 In every age, and sometimes in the most unlikely places... 658 00:46:38,671 --> 00:46:41,333 ...there are those who wish with a great passion... 659 00:46:41,540 --> 00:46:43,337 ...to understand the world. 660 00:46:43,542 --> 00:46:46,534 We don't know where the next discovery will come from. 661 00:46:46,746 --> 00:46:51,410 What dream of the mind's eye will remake the world. 662 00:46:57,123 --> 00:47:01,321 These dreams begin as impossibilities. 663 00:47:04,263 --> 00:47:08,757 Once, even to see a planet through a telescope was an astonishment. 664 00:47:08,968 --> 00:47:10,526 But we studied these worlds... 665 00:47:10,736 --> 00:47:13,398 ...we figured out how they moved in their orbits... 666 00:47:13,606 --> 00:47:16,473 ...and soon we were planning voyages of discovery... 667 00:47:16,676 --> 00:47:18,109 ...beyond the Earth... 668 00:47:18,310 --> 00:47:22,804 ...and sending robot explorers to the planets and the stars. 669 00:47:37,630 --> 00:47:41,760 We humans long to be connected with our origins... 670 00:47:42,735 --> 00:47:45,203 ...so we create rituals. 671 00:47:46,372 --> 00:47:48,966 Science is another way to express this longing. 672 00:47:49,175 --> 00:47:51,439 It also connects us with our origins. 673 00:47:51,644 --> 00:47:56,013 And it, too, has its rituals and its commandments. 674 00:48:04,924 --> 00:48:09,554 Its only sacred truth is that there are no sacred truths. 675 00:48:12,565 --> 00:48:14,465 Temperature systems... 676 00:48:14,834 --> 00:48:17,359 SAGAN: All assumptions must be critically examined. 677 00:48:17,570 --> 00:48:20,835 Arguments from authority are worthless. 678 00:48:24,577 --> 00:48:26,943 FEMALE SCIENTIST: Transducer power is on. 679 00:48:32,551 --> 00:48:34,610 SAGAN: Whatever is inconsistent with the facts... 680 00:48:34,820 --> 00:48:36,913 ...no matter how fond of it we are... 681 00:48:37,123 --> 00:48:40,286 ...must be discarded or revised. 682 00:48:48,801 --> 00:48:51,031 Science is not perfect. 683 00:48:51,237 --> 00:48:52,795 It's often misused. 684 00:48:53,005 --> 00:48:54,870 It's only a tool. 685 00:48:55,141 --> 00:48:56,836 But it's the best tool we have... 686 00:48:57,042 --> 00:48:59,772 ...self-correcting, ever-changing... 687 00:48:59,979 --> 00:49:02,470 ...applicable to everything. 688 00:49:08,387 --> 00:49:12,847 With this tool, we vanquish the impossible. 689 00:49:38,450 --> 00:49:40,111 With the methods of science... 690 00:49:40,319 --> 00:49:43,755 ...we have begun to explore the cosmos. 691 00:49:46,392 --> 00:49:49,020 For the first time, scientific discoveries... 692 00:49:49,228 --> 00:49:51,560 ...are widely accessible. 693 00:49:54,934 --> 00:49:56,401 Our machines... 694 00:49:56,602 --> 00:49:58,092 ...the products of science... 695 00:49:58,304 --> 00:50:00,772 ...are now beyond the orbit of Saturn. 696 00:50:07,379 --> 00:50:09,939 A preliminary spacecraft reconnaissance... 697 00:50:10,149 --> 00:50:13,141 ...has been made of 20 new worlds. 698 00:50:13,819 --> 00:50:16,879 We have learned to value careful observations... 699 00:50:17,089 --> 00:50:19,990 ...to respect the facts, even when they are disquieting... 700 00:50:20,192 --> 00:50:23,184 ...when they seem to contradict conventional wisdom. 701 00:50:24,196 --> 00:50:28,565 The Canterbury monks faithfully recorded an impact on the moon... 702 00:50:28,767 --> 00:50:32,931 ...and the Anasazi people, an explosion of a distant star. 703 00:50:33,138 --> 00:50:36,403 They saw for us as we see for them. 704 00:50:36,609 --> 00:50:40,067 We see further than they only because we stand on their shoulders. 705 00:50:40,279 --> 00:50:41,871 We build on what they knew. 706 00:50:42,081 --> 00:50:44,276 We depend on free inquiry... 707 00:50:44,483 --> 00:50:47,008 ...and free access to knowledge. 708 00:50:47,253 --> 00:50:50,745 We humans have seen the atoms which constitute all of matter... 709 00:50:50,956 --> 00:50:54,756 ...and the forces that sculpt this world and others. 710 00:50:59,899 --> 00:51:01,730 We know the molecules of life... 711 00:51:01,934 --> 00:51:04,767 ...are easily formed under conditions common... 712 00:51:04,970 --> 00:51:07,666 ...throughout the cosmos. 713 00:51:07,873 --> 00:51:11,365 We have mapped the molecular machines at the heart of life. 714 00:51:13,178 --> 00:51:16,670 We have discovered a microcosm in a drop of water. 715 00:51:16,916 --> 00:51:18,713 We have peered into the bloodstream... 716 00:51:18,918 --> 00:51:20,977 ...and down on our stormy planet... 717 00:51:21,186 --> 00:51:24,280 ...to see the Earth as a single organism. 718 00:51:24,490 --> 00:51:26,617 We have found volcanoes on other worlds... 719 00:51:26,825 --> 00:51:28,793 ...and explosions on the sun... 720 00:51:28,994 --> 00:51:31,428 ...studied comets from the depths of space... 721 00:51:31,630 --> 00:51:35,191 ...and traced their origins and destinies... 722 00:51:35,401 --> 00:51:37,164 ...listened to pulsars... 723 00:51:37,369 --> 00:51:40,304 ...and searched for other civilizations. 724 00:51:42,174 --> 00:51:45,575 We humans have set foot on another world... 725 00:51:45,778 --> 00:51:48,372 ...in a place called the Sea of Tranquility... 726 00:51:48,580 --> 00:51:51,879 ...an astonishing achievement for creatures such as we... 727 00:51:52,084 --> 00:51:55,679 ...whose earliest footsteps, 3 ˝ million years old... 728 00:51:55,888 --> 00:52:00,382 ...are preserved in the volcanic ash of East Africa. 729 00:52:00,592 --> 00:52:03,083 We have walked far. 730 00:53:33,585 --> 00:53:36,679 These are some of the things that hydrogen atoms do... 731 00:53:36,889 --> 00:53:41,485 ...given 15 billion years of cosmic evolution. 732 00:53:43,529 --> 00:53:46,657 It has the sound of epic myth. 733 00:53:46,865 --> 00:53:48,298 But it's simply a description... 734 00:53:48,500 --> 00:53:50,161 ...of the evolution of the cosmos... 735 00:53:50,369 --> 00:53:53,827 ...as revealed by science in our time. 736 00:53:54,039 --> 00:53:55,301 And we... 737 00:53:55,507 --> 00:53:58,965 ...we who embody the local eyes and ears... 738 00:53:59,178 --> 00:54:01,476 ...and thoughts and feelings of the cosmos... 739 00:54:01,680 --> 00:54:05,810 ...we've begun, at last, to wonder about our origins. 740 00:54:06,018 --> 00:54:09,385 Star stuff, contemplating the stars... 741 00:54:09,588 --> 00:54:14,184 ...organized collections of 10 billion- billion-billion atoms... 742 00:54:14,393 --> 00:54:16,452 ...contemplating the evolution of matter... 743 00:54:16,662 --> 00:54:21,190 ...tracing that long path by which it arrived at consciousness... 744 00:54:21,400 --> 00:54:23,061 ...here on the planet Earth... 745 00:54:23,268 --> 00:54:26,066 ...and perhaps, throughout the cosmos. 746 00:54:26,738 --> 00:54:31,675 Our loyalties are to the species and the planet. 747 00:54:31,877 --> 00:54:33,970 We speak for Earth. 748 00:54:34,179 --> 00:54:36,670 Our obligation to survive and flourish... 749 00:54:36,882 --> 00:54:39,544 ...is owed not just to ourselves... 750 00:54:39,751 --> 00:54:44,017 ...but also to that cosmos, ancient and vast... 751 00:54:44,223 --> 00:54:46,020 ...from which we spring. 752 00:55:26,665 --> 00:55:30,192 The greatest thrill for me in reliving this adventure... 753 00:55:30,402 --> 00:55:34,463 ...has been not just that we've completed... 754 00:55:34,673 --> 00:55:37,403 ...the preliminary reconnaissance with spacecraft... 755 00:55:37,609 --> 00:55:40,134 ...of the entire solar system. 756 00:55:40,345 --> 00:55:42,370 And not just that we've discovered... 757 00:55:42,581 --> 00:55:46,483 ...astonishing structures in the realm of the galaxies... 758 00:55:46,685 --> 00:55:48,152 ...but especially... 759 00:55:48,353 --> 00:55:53,086 ...that some of Cosmos' boldest dreams about this world... 760 00:55:53,292 --> 00:55:55,453 ...are coming closer to reality. 761 00:55:55,661 --> 00:55:58,687 Since this series' maiden voyage... 762 00:55:58,897 --> 00:56:00,865 ...the impossible has come to pass. 763 00:56:01,066 --> 00:56:06,003 Mighty walls that maintained insuperable ideological differences... 764 00:56:06,305 --> 00:56:08,603 ...have come tumbling down. 765 00:56:08,807 --> 00:56:13,301 Deadly enemies have embraced and begun to work together. 766 00:56:13,512 --> 00:56:15,980 The imperative to cherish the Earth... 767 00:56:16,181 --> 00:56:20,140 ...and to protect the global environment that sustains all of us... 768 00:56:20,352 --> 00:56:22,820 ...has become widely accepted. 769 00:56:23,021 --> 00:56:25,148 And we've begun, finally... 770 00:56:25,357 --> 00:56:26,654 ...the process of reducing... 771 00:56:26,858 --> 00:56:30,726 ...the obscene number of weapons of mass destruction. 772 00:56:30,929 --> 00:56:33,727 Perhaps we have, after all... 773 00:56:33,932 --> 00:56:37,026 ...decided to choose life. 774 00:56:38,604 --> 00:56:41,801 But we still have light-years to go to ensure that choice... 775 00:56:42,007 --> 00:56:46,944 ...even after the summits and the ceremonies and the treaties. 776 00:56:47,145 --> 00:56:52,082 There are still some 50,000 nuclear weapons in the world. 777 00:56:52,417 --> 00:56:56,285 And it would require the detonation of only a tiny fraction of them... 778 00:56:56,488 --> 00:56:58,956 ...to produce a nuclear winter... 779 00:56:59,157 --> 00:57:02,126 ...the predicted global climatic catastrophe... 780 00:57:02,327 --> 00:57:06,263 ...that would result from the smoke and dust lifted into the atmosphere... 781 00:57:06,465 --> 00:57:10,731 ...by burning cities and petroleum facilities. 782 00:57:10,936 --> 00:57:14,872 The world's scientific community has begun to sound the alarm... 783 00:57:15,073 --> 00:57:17,337 ...about the grave dangers posed by... 784 00:57:17,542 --> 00:57:19,976 ...depleting the protective ozone shield... 785 00:57:20,178 --> 00:57:22,305 ...and by greenhouse warming. 786 00:57:22,514 --> 00:57:25,972 And again, we're taking some mitigating steps. 787 00:57:26,184 --> 00:57:29,711 But again, those steps are too small... 788 00:57:29,921 --> 00:57:32,412 ...and too slow. 789 00:57:32,724 --> 00:57:36,353 The discovery that such a thing as nuclear winter was really possible... 790 00:57:36,561 --> 00:57:39,860 ...evolved out of studies of Martian dust storms. 791 00:57:40,065 --> 00:57:43,831 The surface of Mars, fried by ultraviolet light... 792 00:57:44,036 --> 00:57:46,300 ...is also a reminder of why it's important... 793 00:57:46,505 --> 00:57:49,303 ...to keep our ozone layer intact. 794 00:57:49,508 --> 00:57:52,170 The runaway greenhouse effect on Venus... 795 00:57:52,377 --> 00:57:53,901 ...is a valuable reminder... 796 00:57:54,112 --> 00:57:58,606 ...that we must take the increasing greenhouse effect on Earth seriously. 797 00:57:58,817 --> 00:58:02,651 Important lessons about our environment... 798 00:58:02,854 --> 00:58:06,187 ...have come from spacecraft missions to the planets. 799 00:58:06,391 --> 00:58:08,256 By exploring other worlds... 800 00:58:08,460 --> 00:58:10,428 ...we safeguard this one. 801 00:58:10,629 --> 00:58:12,859 By itself, this fact more than justifies... 802 00:58:13,065 --> 00:58:14,999 ...the money our species has spent... 803 00:58:15,200 --> 00:58:18,966 ...in sending ships to other worlds. 804 00:58:19,571 --> 00:58:22,062 It is our fate... 805 00:58:22,274 --> 00:58:25,072 ...to live during one of the most perilous... 806 00:58:25,277 --> 00:58:27,040 ...and one of the most hopeful... 807 00:58:27,245 --> 00:58:29,213 ...chapters in human history. 808 00:58:29,414 --> 00:58:32,110 Our science and our technology... 809 00:58:32,317 --> 00:58:33,841 ...have posed us... 810 00:58:34,052 --> 00:58:36,282 ...a profound question: 811 00:58:36,488 --> 00:58:39,980 Will we learn to use these tools... 812 00:58:40,192 --> 00:58:44,561 ...with wisdom and foresight before it's too late? 813 00:58:44,763 --> 00:58:48,699 Will we see our species safely through this difficult passage... 814 00:58:48,900 --> 00:58:53,030 ...so that our children and grandchildren will continue... 815 00:58:53,238 --> 00:58:56,833 ...the great journey of discovery still deeper... 816 00:58:57,042 --> 00:59:01,536 ...into the mysteries of the cosmos? 817 00:59:01,747 --> 00:59:06,514 That same rocket and nuclear and computer technology... 818 00:59:06,718 --> 00:59:11,621 ...that sends our ships past the farthest known planet... 819 00:59:11,823 --> 00:59:15,953 ...can also be used to destroy our global civilization. 820 00:59:16,161 --> 00:59:18,721 Exactly the same technology... 821 00:59:18,930 --> 00:59:20,830 ...can be used for good... 822 00:59:21,032 --> 00:59:22,590 ...and for evil. 823 00:59:22,801 --> 00:59:25,395 It is as if... 824 00:59:25,604 --> 00:59:27,231 ...there were a god... 825 00:59:27,439 --> 00:59:29,304 ...who said to us: 826 00:59:29,508 --> 00:59:32,909 "I set before you two ways. 827 00:59:33,111 --> 00:59:36,672 You can use your technology to destroy yourselves... 828 00:59:36,882 --> 00:59:41,819 ...or to carry you to the planets and the stars. 829 00:59:42,087 --> 00:59:43,679 It's up to you."