1 00:01:36,048 --> 00:01:39,851 We were born into a mystery, 2 00:01:39,885 --> 00:01:41,886 one that has haunted us 3 00:01:41,920 --> 00:01:44,155 since at least as long as we've been human. 4 00:01:45,924 --> 00:01:49,527 We awakened on this tiny world 5 00:01:49,561 --> 00:01:52,463 beneath a blanket of stars, 6 00:01:52,498 --> 00:01:55,800 like an abandoned baby left on a doorstep 7 00:01:55,834 --> 00:01:58,302 without a note to explain 8 00:01:58,337 --> 00:02:00,972 where we came from, who we are, 9 00:02:01,006 --> 00:02:04,375 how our universe came to be. 10 00:02:04,410 --> 00:02:08,679 And with no idea how to end our cosmic isolation. 11 00:02:08,714 --> 00:02:12,383 We've had to figure it all out for ourselves. 12 00:02:18,023 --> 00:02:20,058 Best thing we had going for us 13 00:02:20,092 --> 00:02:21,526 was our intelligence, 14 00:02:21,560 --> 00:02:25,229 especially our gift for pattern recognition, 15 00:02:25,264 --> 00:02:27,532 sharpened over eons of evolution. 16 00:02:27,566 --> 00:02:30,701 The ones who were good at spotting prey and predator, 17 00:02:30,736 --> 00:02:34,238 telling poisonous plants from the nourishing ones, 18 00:02:34,273 --> 00:02:37,275 they had a better chance to live and reproduce. 19 00:02:37,309 --> 00:02:39,711 They survived and passed on those genes 20 00:02:39,745 --> 00:02:41,112 for pattern recognition 21 00:02:41,146 --> 00:02:43,214 with its obvious advantages. 22 00:02:43,248 --> 00:02:45,783 Cultures all over the planet 23 00:02:45,818 --> 00:02:48,453 looked up at the same stars 24 00:02:48,487 --> 00:02:51,222 and found different pictures there. 25 00:02:58,263 --> 00:03:00,698 We used this gift for recognizing patterns in nature 26 00:03:00,733 --> 00:03:03,634 to read the calendar in the sky. 27 00:03:06,405 --> 00:03:09,107 The messages written in the stars 28 00:03:09,141 --> 00:03:10,975 told our forefathers and mothers 29 00:03:11,009 --> 00:03:13,878 when to camp and when to move on. 30 00:03:13,912 --> 00:03:15,480 When the migratory herds 31 00:03:15,514 --> 00:03:17,482 and when the rains and the cold would come. 32 00:03:17,516 --> 00:03:19,751 And when they would cease for a time. 33 00:03:19,785 --> 00:03:21,753 When they observed the direct connection 34 00:03:21,787 --> 00:03:23,287 between the motions of the stars 35 00:03:23,322 --> 00:03:25,390 and the seasonal cycles of life on Earth, 36 00:03:25,424 --> 00:03:27,458 they concluded, naturally, 37 00:03:27,493 --> 00:03:29,227 that what happens up there 38 00:03:29,261 --> 00:03:31,629 must be directed at us down here. 39 00:03:31,663 --> 00:03:33,464 It makes sense, right? 40 00:03:33,499 --> 00:03:35,233 If the sky was a calendar 41 00:03:35,267 --> 00:03:37,468 and somebody stuck a Post-it note on top of it, 42 00:03:37,503 --> 00:03:40,405 what else could it be but a message? 43 00:03:40,439 --> 00:03:43,608 And so, when the heavenly order was suddenly violated 44 00:03:43,642 --> 00:03:47,412 by the apparition of a comet in the sky... 45 00:03:47,446 --> 00:03:49,614 they took it personally. 46 00:03:49,648 --> 00:03:51,516 Can we really blame them? 47 00:03:51,550 --> 00:03:54,118 Back then, they had no other logical explanation 48 00:03:54,153 --> 00:03:55,620 for what was happening. 49 00:03:55,654 --> 00:03:57,255 This was long before 50 00:03:57,289 --> 00:03:59,190 anyone had yet to imagine Earth 51 00:03:59,224 --> 00:04:01,325 as a spinning planet with a tilted axis, 52 00:04:01,360 --> 00:04:02,960 revolving around the Sun. 53 00:04:02,995 --> 00:04:06,764 Every ancient human culture made the same mistake, 54 00:04:06,799 --> 00:04:09,000 a comet must be a message, 55 00:04:09,034 --> 00:04:11,836 sent by the gods... or one particular god. 56 00:04:11,870 --> 00:04:15,139 And almost invariably, our ancestors concluded 57 00:04:15,174 --> 00:04:18,976 the news was not good. 58 00:04:19,011 --> 00:04:21,713 It didn't matter if you were an ancient Aztec, 59 00:04:21,747 --> 00:04:26,451 Anglo-Saxon, Babylonian, Hindu. 60 00:04:26,485 --> 00:04:29,854 Comets were portents of doom. 61 00:04:29,888 --> 00:04:31,456 The only difference among them 62 00:04:31,490 --> 00:04:33,758 was the precise nature of the coming disaster. 63 00:04:35,527 --> 00:04:40,365 "Dis-aster," as in the Greek word for "bad star." 64 00:04:40,399 --> 00:04:42,500 To the Masai of East Africa, 65 00:04:42,534 --> 00:04:43,735 a comet meant famine. 66 00:04:43,769 --> 00:04:45,570 To the Zulu in the south, 67 00:04:45,604 --> 00:04:47,138 it meant war. 68 00:04:47,172 --> 00:04:49,240 To the Eghap people of the west, 69 00:04:49,274 --> 00:04:51,175 it meant disease. 70 00:04:51,210 --> 00:04:52,410 To the Djaga of Zaire, 71 00:04:52,444 --> 00:04:55,980 specifically "smallpox." 72 00:04:56,015 --> 00:04:57,415 To their neighbors, the Luba, 73 00:04:57,449 --> 00:05:01,185 a comet foretold the death of a leader. 74 00:05:01,220 --> 00:05:05,189 The ancient Chinese were remarkably systematic. 75 00:05:05,224 --> 00:05:09,093 Starting in roughly 1400 BC, 76 00:05:09,128 --> 00:05:11,496 they began recording and cataloguing 77 00:05:11,530 --> 00:05:13,231 the apparitions of comets. 78 00:05:13,265 --> 00:05:14,666 A three-tailed comet 79 00:05:14,700 --> 00:05:16,434 meant calamity for the state. 80 00:05:16,468 --> 00:05:17,935 A four-tailed comet 81 00:05:17,970 --> 00:05:20,238 signified an epidemic was coming. 82 00:05:20,272 --> 00:05:23,074 The human talent for pattern recognition 83 00:05:23,108 --> 00:05:25,109 is a two-edged sword. 84 00:05:25,144 --> 00:05:27,612 We're especially good at finding patterns, 85 00:05:27,646 --> 00:05:30,615 even when they aren't really there-- 86 00:05:30,649 --> 00:05:33,084 something known as "false pattern recognition." 87 00:05:37,389 --> 00:05:39,290 We hunger for significance, 88 00:05:39,325 --> 00:05:41,859 for signs that our personal existence 89 00:05:41,894 --> 00:05:44,295 is of special meaning to the universe. 90 00:05:46,565 --> 00:05:48,933 To that end, we're all too eager 91 00:05:48,968 --> 00:05:51,069 to deceive ourselves and others, 92 00:05:51,103 --> 00:05:54,605 to discern a sacred image in a grilled cheese sandwich 93 00:05:54,640 --> 00:05:57,742 or find a divine warning in a comet. 94 00:05:57,776 --> 00:06:00,478 Today, we know exactly where comets come from 95 00:06:00,512 --> 00:06:03,848 and what they're made of. 96 00:06:05,784 --> 00:06:07,585 Our Ship of the Imagination, 97 00:06:07,620 --> 00:06:11,422 fueled by equal parts of science and wonder, 98 00:06:11,457 --> 00:06:15,493 can take us anywhere in space and time. 99 00:06:15,527 --> 00:06:17,895 It can travel faster than light 100 00:06:17,930 --> 00:06:19,297 and render visible those things 101 00:06:19,331 --> 00:06:21,299 that cannot be seen. 102 00:06:21,333 --> 00:06:23,601 It's carrying us to a mysterious realm 103 00:06:23,636 --> 00:06:26,271 that lies one light-year from the Sun. 104 00:06:27,473 --> 00:06:29,507 What is this swarm of worlds? 105 00:06:29,541 --> 00:06:31,976 Was it organized by alien beings? 106 00:06:32,011 --> 00:06:33,244 No. 107 00:06:33,279 --> 00:06:34,679 Just gravity. 108 00:06:34,713 --> 00:06:37,115 These are the snows of yesteryear, 109 00:06:37,149 --> 00:06:40,251 drifting mountains of ice and rock, 110 00:06:40,286 --> 00:06:43,021 the preserved remnants of the birth of the solar system. 111 00:06:43,055 --> 00:06:45,256 It's called the Oort Cloud, 112 00:06:45,291 --> 00:06:47,825 after Jan Oort, the Dutch astronomer 113 00:06:47,860 --> 00:06:49,093 who foretold its existence 114 00:06:49,128 --> 00:06:51,529 back in 1950. 115 00:06:51,563 --> 00:06:53,831 He was trying to solve a paradox. 116 00:06:53,866 --> 00:06:57,168 There's so many ways for comets to die. 117 00:06:57,202 --> 00:06:59,437 Because they cross the orbits of planets, 118 00:06:59,471 --> 00:07:01,773 comets frequently collide with them. 119 00:07:01,807 --> 00:07:04,776 Comets are largely made of ice, 120 00:07:04,810 --> 00:07:06,611 so every time they come near the Sun, 121 00:07:06,645 --> 00:07:09,614 they lose a part of themselves through evaporation. 122 00:07:09,648 --> 00:07:12,016 And after several thousand trips, 123 00:07:12,051 --> 00:07:14,052 their ice is all gone, 124 00:07:14,086 --> 00:07:17,121 and what remains of the comet is now an asteroid. 125 00:07:17,156 --> 00:07:20,058 Comets can be gravitationally ejected from the solar system 126 00:07:20,092 --> 00:07:22,026 and exiled into space. 127 00:07:22,061 --> 00:07:23,661 And yet, somehow, 128 00:07:23,696 --> 00:07:25,496 the comets keep coming. 129 00:07:25,531 --> 00:07:28,166 Oort and other astronomers wondered, 130 00:07:28,200 --> 00:07:30,335 "Where do all the comets come from?" 131 00:07:32,671 --> 00:07:35,673 Oort calculated the rate at which new comets appear 132 00:07:35,708 --> 00:07:37,675 and concluded that there must be 133 00:07:37,710 --> 00:07:39,477 a vast, spherical swarm of them, 134 00:07:39,511 --> 00:07:41,679 a few light-years across, 135 00:07:41,714 --> 00:07:44,115 surrounding the Sun. 136 00:07:46,185 --> 00:07:49,654 Oort's logic still holds up, 137 00:07:49,688 --> 00:07:52,056 even after all the discoveries we've made about comets 138 00:07:52,091 --> 00:07:54,859 and the solar system in the many decades since. 139 00:07:54,894 --> 00:07:57,862 And yet, the Oort Cloud is a sight 140 00:07:57,897 --> 00:08:00,765 that no one has ever seen. 141 00:08:00,799 --> 00:08:02,033 Nor could we. 142 00:08:02,067 --> 00:08:04,335 It's dark out here. 143 00:08:04,370 --> 00:08:07,438 And each comet is about as far from its closest neighbor 144 00:08:07,473 --> 00:08:09,407 as the Earth is from Saturn. 145 00:08:09,441 --> 00:08:12,610 But science gives us special powers of our own. 146 00:08:12,645 --> 00:08:14,712 It gave Jan Oort 147 00:08:14,747 --> 00:08:16,748 the gift of prophecy. 148 00:08:16,782 --> 00:08:19,117 Oort was also the first to correctly estimate 149 00:08:19,151 --> 00:08:21,085 the distance between the Sun 150 00:08:21,120 --> 00:08:22,587 and the center of our galaxy. 151 00:08:22,621 --> 00:08:24,555 That's a big deal-- 152 00:08:24,590 --> 00:08:26,925 finding out where we are in the Milky Way. 153 00:08:26,959 --> 00:08:28,393 Our star is about 154 00:08:28,427 --> 00:08:31,095 30,000 light-years from the center. 155 00:08:31,130 --> 00:08:32,530 Oort was also 156 00:08:32,564 --> 00:08:34,365 the first guy to use a radio telescope 157 00:08:34,400 --> 00:08:36,701 to map the galaxy's spiral structure. 158 00:08:36,735 --> 00:08:39,804 And he discovered that the center of our galaxy 159 00:08:39,838 --> 00:08:43,241 was a place of titanic explosions, 160 00:08:43,275 --> 00:08:44,475 the first indication 161 00:08:44,510 --> 00:08:45,977 that there might have been 162 00:08:46,011 --> 00:08:48,046 a supermassive black hole lurking there. 163 00:08:48,080 --> 00:08:49,714 Does the fact that most of us know 164 00:08:49,748 --> 00:08:51,950 the names of mass murderers, 165 00:08:51,984 --> 00:08:53,785 but never heard of Jan Oort, 166 00:08:53,819 --> 00:08:56,020 say anything about us? 167 00:09:04,964 --> 00:09:07,565 The Oort Cloud is so enormous 168 00:09:07,600 --> 00:09:10,101 that it takes one of its comets about a million years 169 00:09:10,135 --> 00:09:13,004 to complete a single trip around the Sun. 170 00:09:16,375 --> 00:09:18,576 Out here, at the far edge of the solar system, 171 00:09:18,611 --> 00:09:21,746 even a little tug from the gravity of a passing star 172 00:09:21,780 --> 00:09:23,748 can liberate some of these comets 173 00:09:23,782 --> 00:09:27,051 from their gravitational bondage to the Sun. 174 00:09:30,789 --> 00:09:33,825 Some comets are flung out of the solar system 175 00:09:33,859 --> 00:09:35,293 to wander interstellar space. 176 00:09:35,327 --> 00:09:37,729 But for others, there's a different fate. 177 00:09:44,537 --> 00:09:47,472 This one is plunging towards the Sun, 178 00:09:47,506 --> 00:09:50,208 gaining speed in an unbroken free fall 179 00:09:50,242 --> 00:09:52,677 that lasts hundreds of thousands of years. 180 00:09:54,547 --> 00:09:56,781 When Neptune's gravity gives it another tug, 181 00:09:56,815 --> 00:10:00,285 there's a small change in course. 182 00:10:00,319 --> 00:10:01,853 Mighty Jupiter, the most massive 183 00:10:01,887 --> 00:10:03,288 object in our solar system-- 184 00:10:03,322 --> 00:10:05,990 other than the Sun-- attracts the comet 185 00:10:06,025 --> 00:10:08,026 with its powerful gravitational pull, 186 00:10:08,060 --> 00:10:10,495 bending its path. 187 00:10:13,832 --> 00:10:18,469 When our comet reaches the inner solar system... 188 00:10:18,504 --> 00:10:22,507 heat from the Sun bakes it. 189 00:10:29,848 --> 00:10:33,585 A beautiful transformation begins. 190 00:10:33,619 --> 00:10:36,354 The barren, sooty iceberg 191 00:10:36,388 --> 00:10:39,857 now sports a glowing halo... 192 00:10:39,892 --> 00:10:42,293 and a tail. 193 00:10:49,101 --> 00:10:50,868 These layers tell the story 194 00:10:50,903 --> 00:10:52,203 of how the comet was made, 195 00:10:52,238 --> 00:10:54,639 some four billion years ago. 196 00:10:59,078 --> 00:11:02,747 During the 40,000 generations of humanity, 197 00:11:02,781 --> 00:11:05,350 there must have been roughly 100,000 apparitions 198 00:11:05,384 --> 00:11:07,118 of a bright comet. 199 00:11:07,152 --> 00:11:09,020 For all that time, 200 00:11:09,054 --> 00:11:13,858 the best we could do was look up in helpless wonder, 201 00:11:13,893 --> 00:11:16,361 prisoners of Earth with nowhere to turn 202 00:11:16,395 --> 00:11:19,497 for an explanation beyond our guilt and our fears. 203 00:11:21,166 --> 00:11:24,369 But then a friendship began between two men that led 204 00:11:24,403 --> 00:11:27,105 to a permanent revolution in human thought. 205 00:11:29,241 --> 00:11:32,277 Isaac Newton and Edmond Halley could not know it, 206 00:11:32,311 --> 00:11:36,047 but their collaboration would ultimately set us free 207 00:11:36,081 --> 00:11:39,517 from our long confinement on this tiny world. 208 00:11:44,680 --> 00:11:46,447 The Comet of 1664 209 00:11:46,482 --> 00:11:50,051 sent shivers of dread throughout Europe, 210 00:11:50,085 --> 00:11:52,620 and the terror seemed justified when the Plague 211 00:11:52,654 --> 00:11:55,823 and the Great Fire of London followed soon after. 212 00:11:57,226 --> 00:12:00,661 There, with long bloody hair, 213 00:12:00,696 --> 00:12:03,965 a blazing star threatens the world 214 00:12:03,999 --> 00:12:08,703 with famine, plague and war. 215 00:12:10,339 --> 00:12:13,007 To princes, it spells death... 216 00:12:14,176 --> 00:12:17,211 to kingdoms, many crosses... 217 00:12:17,246 --> 00:12:21,516 to all estates, inevitable losses... 218 00:12:21,550 --> 00:12:24,552 to herdsmen, rot, 219 00:12:24,586 --> 00:12:27,421 to plowmen, hapless seasons, 220 00:12:27,456 --> 00:12:32,026 to sailors, it brings storms, 221 00:12:32,060 --> 00:12:36,030 to cities, civil treasons. 222 00:12:43,105 --> 00:12:45,439 But for one child, 223 00:12:45,474 --> 00:12:48,209 the comet was not the least bit frightening. 224 00:12:52,981 --> 00:12:57,385 For him, it was a thing of wonder. 225 00:12:57,419 --> 00:13:00,455 Like all of us, Edmond Halley was born curious. 226 00:13:00,489 --> 00:13:02,590 Hell's bells! 227 00:13:02,624 --> 00:13:05,726 He was lucky to have a father who encouraged 228 00:13:05,761 --> 00:13:07,428 and nurtured his curiosity, 229 00:13:07,463 --> 00:13:10,465 buying him the best scientific instruments 230 00:13:10,499 --> 00:13:12,400 and even funding his expedition 231 00:13:12,434 --> 00:13:15,436 to make the first accurate star map of the Southern Hemisphere. 232 00:13:15,471 --> 00:13:18,306 Halley dropped out of Oxford when he was 20, 233 00:13:18,340 --> 00:13:20,274 and sailed to St. Helena, 234 00:13:20,309 --> 00:13:23,811 an island below the equator, off the west coast of Africa. 235 00:13:29,151 --> 00:13:30,918 Hell's bells. 236 00:13:30,953 --> 00:13:33,054 The problem was, nobody told Halley 237 00:13:33,088 --> 00:13:34,922 that the weather on St. Helena 238 00:13:34,957 --> 00:13:38,926 was generally lousy; it took him 12 frustrating months 239 00:13:38,961 --> 00:13:43,931 to observe enough southern stars to make a complete map. 240 00:13:43,966 --> 00:13:47,969 The gods and heroes of ancient Greece were now joined 241 00:13:48,003 --> 00:13:51,105 by the mythic figures of a new world and age, 242 00:13:51,140 --> 00:13:55,309 a toucan, a compass, a bird of paradise. 243 00:14:03,685 --> 00:14:06,687 When Halley came home with the other half of the sky, 244 00:14:06,722 --> 00:14:08,656 his map created a sensation. 245 00:14:08,690 --> 00:14:11,826 Now merchants and explorers could navigate by the stars 246 00:14:11,860 --> 00:14:13,594 visible anywhere on Earth. 247 00:14:13,629 --> 00:14:16,664 At the time, the World Society of London 248 00:14:16,698 --> 00:14:18,866 was the world's clearinghouse of scientific discovery. 249 00:14:18,901 --> 00:14:21,636 Its motto, "Nullius in verba," 250 00:14:21,670 --> 00:14:24,372 sums up the heart of the scientific method. 251 00:14:24,406 --> 00:14:27,375 It's Latin for "see for yourself." 252 00:14:27,409 --> 00:14:31,045 In other words, "question authority." 253 00:14:31,079 --> 00:14:32,713 Halley's star maps caught the attention 254 00:14:32,748 --> 00:14:35,016 of the Society's Curator of Experiments. 255 00:14:35,050 --> 00:14:36,784 I'd show him to you if I could, 256 00:14:36,819 --> 00:14:39,854 but no portrait of Robert Hooke exists from his time, 257 00:14:39,888 --> 00:14:42,857 only the verbal descriptions of his contemporaries. 258 00:14:42,891 --> 00:14:46,160 They called him "lean, bent, ugly." 259 00:14:46,195 --> 00:14:49,297 He was possibly the most inventive person who ever lived. 260 00:14:49,331 --> 00:14:51,065 And despite his appearance, 261 00:14:51,099 --> 00:14:54,202 he was the most sought-after party guest in all of London. 262 00:14:54,236 --> 00:14:55,970 Why? 263 00:14:56,004 --> 00:14:58,473 Hooke's insatiable curiosity 264 00:14:58,507 --> 00:15:00,541 encompassed absolutely everything. 265 00:15:02,678 --> 00:15:05,513 Hooke discovered a little cosmos, 266 00:15:05,547 --> 00:15:08,883 and we still call it by the name he gave it, the cell. 267 00:15:08,917 --> 00:15:10,685 Hooke discovered the cell by looking 268 00:15:10,719 --> 00:15:13,421 at a piece of cork with one of his own inventions, 269 00:15:13,455 --> 00:15:15,890 the compound microscope. 270 00:15:15,924 --> 00:15:19,227 He anticipated aspects of Darwin's theory of evolution 271 00:15:19,261 --> 00:15:22,330 by almost 200 years. 272 00:15:22,364 --> 00:15:24,432 Hooke also improved the telescope. 273 00:15:24,466 --> 00:15:27,068 The drawings he made of the astronomical bodies he observed 274 00:15:27,102 --> 00:15:29,203 attest to his uncanny precision. 275 00:15:29,238 --> 00:15:33,708 After the Great Fire destroyed central London in 1666, 276 00:15:33,742 --> 00:15:36,511 Hooke partnered with the architect Christopher Wren 277 00:15:36,545 --> 00:15:39,580 to redesign and rebuild the city. 278 00:15:39,615 --> 00:15:43,518 Hooke was the foremost experimentalist of his age. 279 00:15:43,552 --> 00:15:44,886 Using coiled springs, 280 00:15:44,920 --> 00:15:46,621 he derived the "law of elasticity," 281 00:15:46,655 --> 00:15:49,123 known today as Hooke's Law. 282 00:15:49,158 --> 00:15:51,592 He perfected the air pump, 283 00:15:51,627 --> 00:15:53,961 the height of technology in its time, 284 00:15:53,996 --> 00:15:57,732 and used it to experiment on respiration and sound. 285 00:15:57,766 --> 00:16:00,768 And he experimented with cannabis. 286 00:16:00,803 --> 00:16:03,437 He reported to a meeting of the Royal Society 287 00:16:03,472 --> 00:16:06,107 that a sea captain friend of his quote 288 00:16:06,141 --> 00:16:08,709 "had so often experimented with it, 289 00:16:08,744 --> 00:16:10,311 that there is no cause of fear, 290 00:16:10,345 --> 00:16:13,247 though possibly there may be of laughter." 291 00:16:17,486 --> 00:16:20,121 But coffee was the drug of choice for England 292 00:16:20,155 --> 00:16:21,622 in the 17th century. 293 00:16:21,657 --> 00:16:24,125 Coffeehouses sprang up all over London. 294 00:16:36,472 --> 00:16:39,507 This is where people came to get news, 295 00:16:39,541 --> 00:16:43,244 to launch new ventures, and to debate ideas. 296 00:16:43,278 --> 00:16:45,646 The coffeehouse was an oasis of equality 297 00:16:45,681 --> 00:16:48,316 in a class-obsessed society. 298 00:16:48,350 --> 00:16:50,985 Here, a poor man needn't give up his seat 299 00:16:51,019 --> 00:16:53,788 to a rich man, nor submit to his opinion. 300 00:16:53,822 --> 00:16:56,124 It was a kind of laboratory of democracy. 301 00:16:56,158 --> 00:16:58,793 In this highly caffeinated atmosphere, 302 00:16:58,827 --> 00:17:03,531 Halley and Hooke met Christopher Wren to discuss a deep mystery. 303 00:17:03,565 --> 00:17:06,968 Why do the planets move as they do? 304 00:17:07,002 --> 00:17:09,504 The astronomer Johannes Kepler had demonstrated, 305 00:17:09,538 --> 00:17:11,005 some 80 years before, 306 00:17:11,039 --> 00:17:13,608 that the orbits of the planets around the Sun 307 00:17:13,642 --> 00:17:17,011 were not perfect circles, but actually ellipses, 308 00:17:17,045 --> 00:17:20,314 and that the closer a planet was to the Sun, 309 00:17:20,349 --> 00:17:23,284 the faster it moved. 310 00:17:23,318 --> 00:17:25,170 Why? 311 00:17:25,587 --> 00:17:28,156 Could some invisible force from the Sun be responsible 312 00:17:28,158 --> 00:17:29,791 for this change in motion? 313 00:17:29,793 --> 00:17:31,526 If so, how did it work? 314 00:17:31,528 --> 00:17:34,929 Could there be a simple mathematical law to describe it? 315 00:17:34,931 --> 00:17:38,733 Maybe something like Hooke's Law of Elasticity? 316 00:17:42,271 --> 00:17:44,038 Perhaps. 317 00:17:44,072 --> 00:17:45,673 But try as he might, 318 00:17:45,707 --> 00:17:47,008 Christopher Wren couldn't figure it out. 319 00:17:48,343 --> 00:17:49,844 Damned if I haven't tried. 320 00:17:49,878 --> 00:17:51,345 It's beyond me. 321 00:17:51,380 --> 00:17:53,347 I'll wager a book worth 40 shillings 322 00:17:53,382 --> 00:17:54,882 to the man who can solve it! 323 00:17:54,917 --> 00:17:57,018 That book is mine, Mr. Wren. 324 00:17:57,052 --> 00:17:58,386 I've already done the calculation. 325 00:17:58,420 --> 00:17:59,720 Halley was delighted. 326 00:17:59,755 --> 00:18:01,556 Show us, Mr. Hooke. 327 00:18:01,590 --> 00:18:05,159 But months passed, and Hooke failed to deliver. 328 00:18:05,194 --> 00:18:06,828 He couldn't do the math. 329 00:18:06,862 --> 00:18:08,663 None of them could. 330 00:18:08,697 --> 00:18:10,998 Finally, Halley had enough of Hooke's excuses. 331 00:18:11,033 --> 00:18:14,068 Halley knew there must be someone, somewhere, 332 00:18:14,103 --> 00:18:16,104 up to the challenge. 333 00:18:22,411 --> 00:18:25,379 What about that mathematician at Cambridge? 334 00:18:25,414 --> 00:18:27,215 Clever fellow. 335 00:18:27,249 --> 00:18:29,584 He had solved central questions about the nature of light 336 00:18:29,618 --> 00:18:33,421 years before, when he was still only 22. 337 00:18:33,455 --> 00:18:35,389 And he invented the reflecting telescope. 338 00:18:35,424 --> 00:18:37,091 Odd bird. 339 00:18:37,126 --> 00:18:39,260 Dropped out of sight a while back. 340 00:18:39,294 --> 00:18:42,396 some squabble over Hooke and his discovery about light. 341 00:18:42,431 --> 00:18:43,965 Went completely to pieces over it 342 00:18:43,999 --> 00:18:46,534 and has been hiding out in Cambridge ever since. 343 00:18:46,568 --> 00:18:49,570 Halley wondered if this strange, and by all accounts, 344 00:18:49,605 --> 00:18:52,206 exceedingly difficult man, might succeed 345 00:18:52,241 --> 00:18:53,808 where Hooke and others had failed. 346 00:18:53,842 --> 00:18:55,376 What he couldn't know, 347 00:18:55,410 --> 00:18:58,379 what no one could possibly imagine at the time, 348 00:18:58,413 --> 00:18:59,914 were the countless ways 349 00:18:59,948 --> 00:19:03,217 the world would be forever changed by this meeting 350 00:19:03,252 --> 00:19:05,686 on an August day in 1684. 351 00:19:11,123 --> 00:19:13,725 Isaac Newton was born in England 352 00:19:13,759 --> 00:19:16,027 on Christmas Day in 1642. 353 00:19:17,963 --> 00:19:21,900 Before he even opened his eyes, his father was already dead. 354 00:19:23,936 --> 00:19:26,838 His mother left him when he was only three 355 00:19:26,872 --> 00:19:29,941 and did not return until he was 11. 356 00:19:29,975 --> 00:19:33,745 When she did, it was with a new family and husband, 357 00:19:33,779 --> 00:19:36,381 a stepfather who Isaac Newton despised. 358 00:19:41,587 --> 00:19:44,789 Newton's refuge from his miserable family life 359 00:19:44,824 --> 00:19:48,626 was his passion to understand how things worked, 360 00:19:48,661 --> 00:19:51,696 especially nature itself. 361 00:19:51,730 --> 00:19:55,433 In 1661, the talented young Isaac entered Trinity College 362 00:19:55,468 --> 00:19:57,569 at Cambridge University 363 00:19:57,603 --> 00:20:00,238 where he was a consistently lousy student, 364 00:20:00,272 --> 00:20:03,074 one without friends or a loving family 365 00:20:03,109 --> 00:20:05,643 to provide any warmth or encouragement. 366 00:20:05,678 --> 00:20:09,314 Newton mostly kept to himself, sequestered in his room, 367 00:20:09,348 --> 00:20:11,816 studying ancient Greek philosophers, 368 00:20:11,851 --> 00:20:14,119 geometry and languages, 369 00:20:14,153 --> 00:20:15,887 and pondering deep questions 370 00:20:15,921 --> 00:20:20,892 on the nature of matter, space, time, and motion. 371 00:20:20,926 --> 00:20:25,597 This budding scientist was also a passionate mystic. 372 00:20:25,631 --> 00:20:27,298 Newton believed that a secret knowledge 373 00:20:27,333 --> 00:20:29,634 called alchemy, known only to a small group 374 00:20:29,668 --> 00:20:33,671 of ancient philosophers, was waiting to be rediscovered. 375 00:20:33,706 --> 00:20:37,342 He hoped to learn how to change ordinary metals 376 00:20:37,376 --> 00:20:38,977 into silver and gold, 377 00:20:39,011 --> 00:20:41,846 and maybe even cook up the elixir of life, 378 00:20:41,881 --> 00:20:44,015 the key to to immortality. 379 00:20:45,017 --> 00:20:47,919 He was also obsessed 380 00:20:47,953 --> 00:20:51,156 with finding hidden messages in the words of the Bible. 381 00:20:51,190 --> 00:20:55,493 He combed through translations in several different languages, 382 00:20:55,528 --> 00:20:58,797 hoping to decipher coded instructions from God. 383 00:21:05,004 --> 00:21:07,205 He made elaborate calculations in an effort 384 00:21:07,239 --> 00:21:11,609 to discover the date of the Second Coming. 385 00:21:11,644 --> 00:21:13,511 His lifelong research in alchemy 386 00:21:13,546 --> 00:21:16,681 and biblical chronology never led anywhere. 387 00:21:21,353 --> 00:21:24,189 When Halley found Newton that fateful day, 388 00:21:24,223 --> 00:21:28,526 he was living as a virtual recluse. 389 00:21:31,163 --> 00:21:34,065 Newton had gone into hiding 13 years earlier, 390 00:21:34,100 --> 00:21:38,737 after Robert Hooke had publicly accused Newton of stealing 391 00:21:38,771 --> 00:21:40,972 his groundbreaking work on light and color. 392 00:21:41,006 --> 00:21:44,008 In fact, it was Isaac Newton 393 00:21:44,043 --> 00:21:45,877 who solved the mystery of the spectrum of light, 394 00:21:45,911 --> 00:21:48,680 not Robert Hooke. 395 00:21:48,714 --> 00:21:50,849 This wound was painful and deep, 396 00:21:50,883 --> 00:21:53,651 and Newton resolved to never expose himself to that kind 397 00:21:53,686 --> 00:21:55,320 of public humiliation ever again. 398 00:21:55,354 --> 00:21:58,356 Sir, I don't suppose you recall 399 00:21:58,390 --> 00:22:00,392 our meeting a few years ago? 400 00:22:00,426 --> 00:22:02,360 Yes, Mr. Halley. 401 00:22:02,394 --> 00:22:03,895 I'm sorry to bother you. 402 00:22:03,929 --> 00:22:06,765 Never mind the formalities, get to your point. 403 00:22:06,799 --> 00:22:10,034 I've been talking with our friends, Mr. Wren and Mr. Hooke. 404 00:22:10,069 --> 00:22:13,037 That scoundrel Hooke's no friend of mine. 405 00:22:13,072 --> 00:22:14,839 Yes, I understand, sir. 406 00:22:14,874 --> 00:22:16,875 But the thing is we've been debating 407 00:22:16,909 --> 00:22:19,778 the puzzling question of planetary motion. 408 00:22:19,812 --> 00:22:21,679 We all agree that some force of attraction 409 00:22:21,714 --> 00:22:24,382 from the Sun governs the motions of the planets. 410 00:22:24,417 --> 00:22:27,352 We suspect there must be a mathematical law 411 00:22:27,386 --> 00:22:29,020 to describe how this force 412 00:22:29,054 --> 00:22:31,523 changes with distance. 413 00:22:31,557 --> 00:22:32,857 And knowing of your skill... 414 00:22:32,892 --> 00:22:34,192 Yes, yes, the attraction of gravity 415 00:22:34,226 --> 00:22:36,428 weakens with the square of the distance. 416 00:22:36,462 --> 00:22:39,030 That's why the planets move in ellipses. 417 00:22:39,064 --> 00:22:41,633 But, sir, how can you know this? 418 00:22:41,667 --> 00:22:44,569 Why, I have calculated it some five years ago. 419 00:22:44,603 --> 00:22:47,472 I beg you, show it to me. 420 00:22:47,506 --> 00:22:48,873 The calculation is here... 421 00:22:48,908 --> 00:22:50,875 somewhere. 422 00:22:50,910 --> 00:22:52,110 Well, no matter. 423 00:22:52,144 --> 00:22:53,578 I shall redo it and be sure 424 00:22:53,612 --> 00:22:54,646 to send it on to you. 425 00:22:54,680 --> 00:22:56,114 This is stupendous! 426 00:22:56,148 --> 00:22:58,416 Why have we not had word of it before? 427 00:22:58,451 --> 00:23:00,251 Newton remembered all too well 428 00:23:00,286 --> 00:23:03,288 what Hooke had done to him 429 00:23:03,322 --> 00:23:05,957 the last time he put forth an idea. 430 00:23:05,991 --> 00:23:08,059 Just when Halley may have begun to wonder 431 00:23:08,094 --> 00:23:11,229 if Newton was bluffing as Hooke had done earlier, 432 00:23:11,263 --> 00:23:15,100 a messenger arrived with an envelope from Newton. 433 00:23:18,003 --> 00:23:21,773 Here are the opening pages of modern science 434 00:23:21,807 --> 00:23:25,076 with its all-embracing vision of nature... 435 00:23:25,111 --> 00:23:28,847 universal laws of motion, gravity... 436 00:23:28,881 --> 00:23:30,482 not just for the Earth, 437 00:23:30,516 --> 00:23:33,451 but for the cosmos. 438 00:23:33,486 --> 00:23:36,755 Halley raced back to Cambridge. 439 00:23:36,789 --> 00:23:39,824 Mr. Newton, I beseech you to work all of this 440 00:23:39,859 --> 00:23:42,427 into a book as soon as possible. 441 00:23:42,461 --> 00:23:45,930 I can assure you the Royal Society will publish it. 442 00:23:45,965 --> 00:23:47,799 But there was one little problem. 443 00:23:47,833 --> 00:23:50,268 We are in agreement 444 00:23:50,302 --> 00:23:53,438 that Mr. Newton has produced a masterpiece. 445 00:23:53,472 --> 00:23:57,108 However, I'm afraid the Royal Society has... 446 00:23:57,143 --> 00:24:01,045 well, regrettably sales for the History of Fish... 447 00:24:01,080 --> 00:24:04,983 have not lived up to our financial expectations. 448 00:24:05,017 --> 00:24:07,819 It's an impressive book. 449 00:24:07,853 --> 00:24:09,721 Extremely comprehensive. 450 00:24:09,755 --> 00:24:11,523 Really. 451 00:24:11,557 --> 00:24:15,060 It's filled with lavish illustrations of... 452 00:24:15,094 --> 00:24:18,530 well, fish. 453 00:24:18,564 --> 00:24:20,965 The disappointing sales led to a bigger problem. 454 00:24:21,000 --> 00:24:23,501 The Royal Society pretty much blew 455 00:24:23,536 --> 00:24:26,504 its total annual budget on the History of Fish. 456 00:24:26,539 --> 00:24:29,240 In fact, they were so strapped for cash, 457 00:24:29,275 --> 00:24:31,676 they had to pay poor Halley's salary 458 00:24:31,710 --> 00:24:34,379 with copies of their worst-selling book. 459 00:24:34,413 --> 00:24:37,582 With no money to print Newton's Principia, 460 00:24:37,616 --> 00:24:40,718 the scientific revolution hung in the balance. 461 00:24:43,219 --> 00:24:45,113 Without Halley's heroic efforts, 462 00:24:45,190 --> 00:24:47,257 the reclusive Newton's masterwork 463 00:24:47,343 --> 00:24:49,364 might never have seen the light of day. 464 00:24:49,707 --> 00:24:51,907 But Halley was a man on a mission, 465 00:24:51,909 --> 00:24:55,511 absolutely determined to bring Newton's genius to the world. 466 00:24:55,513 --> 00:24:58,080 That pre-scientific world, 467 00:24:58,082 --> 00:25:00,549 the world ruled by fear, 468 00:25:00,551 --> 00:25:03,686 was poised at the edge of a revolution. 469 00:25:03,688 --> 00:25:07,056 Everything depended on whether or not Edmond Halley 470 00:25:07,058 --> 00:25:10,059 could get Newton's book out to the wider world. 471 00:25:10,061 --> 00:25:12,861 Halley resolved not only to edit Newton's book, 472 00:25:12,863 --> 00:25:15,864 but to publish it at his own expense. 473 00:25:15,866 --> 00:25:17,766 Newton completed the first two volumes, 474 00:25:17,768 --> 00:25:19,968 laying the mathematical framework 475 00:25:19,970 --> 00:25:22,538 for the physics of motion. 476 00:25:22,540 --> 00:25:25,574 The third volume would settle once and for all 477 00:25:25,576 --> 00:25:27,443 who won the coffeehouse wager. 478 00:25:27,445 --> 00:25:29,712 Newton applied his principles to explain 479 00:25:29,714 --> 00:25:31,847 all the known motions of the Earth, 480 00:25:31,849 --> 00:25:34,216 the Moon and the planets. 481 00:25:34,218 --> 00:25:37,186 Unfortunately, there was this problem. 482 00:25:37,220 --> 00:25:39,021 Now Halley also took on the role 483 00:25:39,055 --> 00:25:41,957 of Newton's psychotherapist. 484 00:25:41,992 --> 00:25:45,327 Isaac, I'm afraid that Mr. Hooke requires 485 00:25:45,362 --> 00:25:48,664 an acknowledgment in the preface of your third volume. 486 00:25:48,698 --> 00:25:49,998 But I have done so. 487 00:25:50,033 --> 00:25:52,134 Thanking him, Mr. Wren and yourself 488 00:25:52,168 --> 00:25:55,237 for prodding me to think again on astronomical matters. 489 00:25:55,271 --> 00:25:58,474 Mr. Hooke has been going about London saying 490 00:25:58,508 --> 00:26:00,976 that you got the Law of Gravity from him. 491 00:26:01,011 --> 00:26:02,578 Why, that litigious little... 492 00:26:02,612 --> 00:26:03,912 Never! 493 00:26:03,947 --> 00:26:05,748 I would sooner burn the third volume 494 00:26:05,782 --> 00:26:07,750 than deface it with such a lie. 495 00:26:07,784 --> 00:26:09,218 To hell with Hooke. 496 00:26:09,252 --> 00:26:10,552 He will be long forgotten 497 00:26:10,587 --> 00:26:12,888 when your ideas are still being celebrated. 498 00:26:14,758 --> 00:26:18,827 More copies of that dreadful book? 499 00:26:18,862 --> 00:26:21,563 Wherever shall we put them all? 500 00:26:21,598 --> 00:26:23,098 We talked about this, Mary, dear. 501 00:26:23,133 --> 00:26:25,768 This is my salary from the Society. 502 00:26:25,802 --> 00:26:28,570 They have nothing else with which to pay me. 503 00:26:28,605 --> 00:26:30,839 If only Mr. Hooke and Mr. Newton 504 00:26:30,874 --> 00:26:32,875 were more like you. 505 00:26:32,909 --> 00:26:34,877 Halley and Wren decided to confront Hooke 506 00:26:34,911 --> 00:26:36,545 about his false claims. 507 00:26:36,579 --> 00:26:39,181 That law is mine, I tell you! 508 00:26:39,215 --> 00:26:40,549 I proved it first. 509 00:26:40,583 --> 00:26:42,384 Then fetch your proof here at once. 510 00:26:42,419 --> 00:26:43,619 Let us see it. 511 00:26:43,653 --> 00:26:47,222 Surely we have waited on it long enough. 512 00:26:47,257 --> 00:26:50,359 You'll simply have to take my word for it. 513 00:26:50,393 --> 00:26:52,761 Empty claims may persuade elsewhere, 514 00:26:52,796 --> 00:26:54,963 but not here. 515 00:26:54,998 --> 00:26:57,599 Put up or shut up, Mr. Hooke. 516 00:26:59,002 --> 00:27:01,136 Blasted Newton. I'll make him pay. 517 00:27:16,653 --> 00:27:20,088 If it wasn't for Edmond Halley, 518 00:27:20,123 --> 00:27:22,257 Newton's great book would've never been conceived, 519 00:27:22,292 --> 00:27:24,793 nor written, nor printed. 520 00:27:24,827 --> 00:27:27,095 Okay. So what? 521 00:27:27,130 --> 00:27:29,264 What difference does that make to us? 522 00:27:29,299 --> 00:27:32,067 What's the big deal? 523 00:27:37,340 --> 00:27:40,475 When Isaac Newton was born in this house 524 00:27:40,510 --> 00:27:44,146 in 1642, the world was very different. 525 00:27:44,180 --> 00:27:46,381 Everyone looked at the perfection 526 00:27:46,416 --> 00:27:49,051 of the clockwork motions of the planets in the sky 527 00:27:49,085 --> 00:27:50,986 and could only understand it as the work 528 00:27:51,020 --> 00:27:52,654 of a master clock maker. 529 00:27:52,689 --> 00:27:54,756 How else to explain it? 530 00:27:54,791 --> 00:27:57,125 There was only one way such a thing could come about 531 00:27:57,160 --> 00:27:58,593 in their imagination; 532 00:27:58,628 --> 00:28:00,629 only one answer for them-- 533 00:28:00,663 --> 00:28:02,097 God. 534 00:28:02,131 --> 00:28:04,399 For reasons beyond our understanding, 535 00:28:04,434 --> 00:28:06,969 God just created the solar system that way. 536 00:28:07,003 --> 00:28:09,938 But this explanation is the closing of a door. 537 00:28:09,973 --> 00:28:13,508 It doesn't lead to other questions. 538 00:28:23,653 --> 00:28:24,953 Along came Newton, 539 00:28:24,988 --> 00:28:28,090 a God-loving man who's also a genius. 540 00:28:28,124 --> 00:28:30,258 He could write the laws of nature 541 00:28:30,293 --> 00:28:32,694 in perfect mathematical sentences-- 542 00:28:32,729 --> 00:28:35,163 formulas that applied universally 543 00:28:35,198 --> 00:28:38,133 to apples, moons, planets 544 00:28:38,167 --> 00:28:40,335 and so much more. 545 00:28:42,372 --> 00:28:45,207 With one foot still in the Middle Ages, 546 00:28:45,241 --> 00:28:48,477 Isaac Newton imagined the whole solar system. 547 00:28:48,511 --> 00:28:50,846 Newton's laws of gravity and motion 548 00:28:50,880 --> 00:28:54,716 revealed how the Sun held distant worlds captive. 549 00:28:54,751 --> 00:28:56,885 His laws swept away the need 550 00:28:56,919 --> 00:28:58,520 for a master clock maker 551 00:28:58,554 --> 00:29:01,990 to explain the precision and beauty of the solar system. 552 00:29:02,025 --> 00:29:05,227 Gravity is the clock maker. 553 00:29:05,261 --> 00:29:08,630 Matter obeyed commandments we could discover, 554 00:29:08,665 --> 00:29:11,233 laws the Bible hadn't mentioned. 555 00:29:11,267 --> 00:29:14,236 Newton's answer to why the solar system is the way it is 556 00:29:14,270 --> 00:29:17,806 opened the way to an infinite number of questions. 557 00:29:17,840 --> 00:29:19,841 Principia also happened to include 558 00:29:19,876 --> 00:29:21,843 the invention of calculus, 559 00:29:21,878 --> 00:29:24,479 and the first sound theoretical basis 560 00:29:24,514 --> 00:29:26,982 for an end to our imprisonment on Earth-- 561 00:29:27,016 --> 00:29:29,184 space travel. 562 00:29:32,588 --> 00:29:35,257 Newton envisioned the firing of a cannonball... 563 00:29:37,060 --> 00:29:39,561 with increasingly greater explosive thrust. 564 00:29:42,031 --> 00:29:45,400 He reasoned that with enough velocity, 565 00:29:45,435 --> 00:29:48,003 the bounds of gravity could be broken, 566 00:29:48,037 --> 00:29:49,938 and the cannonball could escape 567 00:29:49,973 --> 00:29:52,274 to orbit the Earth. 568 00:29:52,308 --> 00:29:55,410 This changed everything. 569 00:30:57,340 --> 00:31:01,910 Newton's Principia Mathematica set us free in another way. 570 00:31:01,945 --> 00:31:03,812 By finding the natural laws 571 00:31:03,846 --> 00:31:06,615 governing the comings and goings of comets, 572 00:31:06,649 --> 00:31:08,750 he decoupled the motions of the heavens 573 00:31:08,785 --> 00:31:12,521 from their ancient connections to our fears. 574 00:31:15,084 --> 00:31:18,360 If Halley hadn't been standing next to Newton for all those years, 575 00:31:18,395 --> 00:31:23,402 perhaps the world would remember him for his own accomplishments and discoveries. 576 00:31:23,437 --> 00:31:26,539 But the only thing that comes to mind for most people 577 00:31:26,574 --> 00:31:31,023 is the comet, the irony is that discovering a comet 578 00:31:31,058 --> 00:31:34,941 is actually one of the few things that Halley never did. 579 00:31:39,966 --> 00:31:42,588 An ice to starboard 580 00:31:42,623 --> 00:31:44,404 Come About.. 581 00:31:47,619 --> 00:31:50,230 After the publication of the Principia 582 00:31:50,265 --> 00:31:54,117 Halley was commanded by his king to lead three ocean voyages, 583 00:31:54,152 --> 00:31:58,687 scientific expeditions to solve navigational problems for the British navy. 584 00:31:58,722 --> 00:32:04,353 Halley used this opportunity to make the first map of the Earth's magnetic field 585 00:32:08,114 --> 00:32:10,983 And he was also a businessman. 586 00:32:13,086 --> 00:32:15,888 Halley perfected the diving bell... 587 00:32:17,424 --> 00:32:19,525 ...and used his invention to start 588 00:32:19,559 --> 00:32:22,628 a flourishing commercial salvage operation. 589 00:32:26,900 --> 00:32:29,068 Mmm, ah, Dr. Halley's gone and done it this time. 590 00:32:29,102 --> 00:32:32,304 I reckon he's been down there at least three hours. 591 00:32:32,338 --> 00:32:35,040 Not one to risk the lives of others, 592 00:32:35,075 --> 00:32:38,477 Halley personally tested his own invention. 593 00:32:42,115 --> 00:32:45,617 I make it exactly four hours since our descent. 594 00:32:45,652 --> 00:32:47,753 Not at all bad for ten fathoms. 595 00:32:53,093 --> 00:32:55,027 He invented the weather map. 596 00:32:57,797 --> 00:33:01,333 And the symbols he devised for indicating prevailing winds 597 00:33:01,367 --> 00:33:03,802 are still in use today. 598 00:33:13,513 --> 00:33:16,148 Halley laid the groundwork 599 00:33:16,182 --> 00:33:18,250 for the science of population statistics. 600 00:33:18,284 --> 00:33:19,585 How? 601 00:33:19,619 --> 00:33:22,588 He compared the birth, marriage, death, 602 00:33:22,622 --> 00:33:25,491 and population densities of London and Paris. 603 00:33:25,525 --> 00:33:27,793 He actually had to pace off 604 00:33:27,827 --> 00:33:28,961 the entire perimeter of Paris, on foot, 605 00:33:28,995 --> 00:33:31,196 to learn its true dimensions. 606 00:33:31,231 --> 00:33:32,598 He came to the conclusion 607 00:33:32,632 --> 00:33:34,333 that since roughly half of all adults fail 608 00:33:34,367 --> 00:33:35,801 to reproduce children, 609 00:33:35,835 --> 00:33:37,803 who themselves survive to reproduce, 610 00:33:37,837 --> 00:33:40,706 every married couple must have four children 611 00:33:40,740 --> 00:33:43,208 in order to maintain the population. 612 00:33:46,212 --> 00:33:48,814 And it was Edmond Halley who gave us 613 00:33:48,848 --> 00:33:50,449 the actual scale of the solar system. 614 00:33:50,483 --> 00:33:53,018 He figured out a clever way to find the distance 615 00:33:53,053 --> 00:33:54,553 from Earth to the Sun. 616 00:33:54,587 --> 00:33:56,822 It involved precisely measuring the time it took 617 00:33:56,856 --> 00:34:00,192 for the planet Venus to cross the Sun's disc. 618 00:34:03,163 --> 00:34:05,964 27 years after Halley's death, 619 00:34:05,999 --> 00:34:09,334 Captain James Cook made his first voyage to Tahiti 620 00:34:09,369 --> 00:34:11,904 for the express purpose of testing Halley's method 621 00:34:11,938 --> 00:34:14,506 during a transit of Venus across the Sun. 622 00:34:14,541 --> 00:34:16,909 Using a special filter to protect his vision 623 00:34:16,943 --> 00:34:20,079 from being destroyed by looking directly at the Sun, 624 00:34:20,113 --> 00:34:22,815 Cook and his men made it possible for us to know 625 00:34:22,849 --> 00:34:27,152 that the Sun is 93 million miles from Earth. 626 00:34:27,187 --> 00:34:29,555 And Halley was the first to realize 627 00:34:29,589 --> 00:34:33,425 that the so-called "fixed" stars were not fixed at all. 628 00:34:33,460 --> 00:34:35,227 How'd he do it? 629 00:34:35,261 --> 00:34:37,830 He pored over the observations made 630 00:34:37,864 --> 00:34:40,499 by the ancient Greek astronomers of the brightest stars. 631 00:34:40,533 --> 00:34:43,235 And he compared their observations with the ones 632 00:34:43,269 --> 00:34:47,272 he himself made of the same stars 1,800 years later. 633 00:34:47,307 --> 00:34:49,541 Why hadn't anyone noticed this before? 634 00:34:49,576 --> 00:34:52,544 Halley figured out that it would only become apparent 635 00:34:52,579 --> 00:34:55,681 if you waited long enough between observations. 636 00:34:55,715 --> 00:34:58,217 It's hard to perceive the motions of things 637 00:34:58,251 --> 00:34:59,551 that are far away. 638 00:34:59,586 --> 00:35:02,254 And the stars are so very far away, 639 00:35:02,288 --> 00:35:04,590 that you would need to track them for many centuries 640 00:35:04,624 --> 00:35:07,960 before you could detect that they moved at all. 641 00:35:09,896 --> 00:35:13,532 Halley discovered the first clue to a magnificent reality, 642 00:35:13,566 --> 00:35:17,970 all the stars are in motion, streaming past each other, 643 00:35:18,004 --> 00:35:20,639 rising and falling like merry-go-round horses 644 00:35:20,673 --> 00:35:26,412 in their Newtonian dance around the center of our galaxy. 645 00:35:26,446 --> 00:35:30,649 And, oh, yes, there was that thing about the comet. 646 00:35:34,421 --> 00:35:37,890 What were those strange and beautiful celestial visitors 647 00:35:37,924 --> 00:35:40,492 that appeared without warning from time to time? 648 00:35:40,527 --> 00:35:44,596 Halley set out to solve this mystery as a detective would, 649 00:35:44,631 --> 00:35:46,932 by gathering all credible eyewitness testimony. 650 00:35:46,966 --> 00:35:49,501 The earliest precise observations of a comet 651 00:35:49,536 --> 00:35:52,404 that Halley could find were made in Constantinople 652 00:35:52,439 --> 00:35:56,742 by Nikephoros Gregoras, a Byzantine astronomer and monk 653 00:35:56,776 --> 00:35:59,011 in June 1337. 654 00:35:59,045 --> 00:36:02,314 Halley hunted down every astronomical observation 655 00:36:02,348 --> 00:36:08,187 of a comet recorded in Europe between 1472 and 1698. 656 00:36:08,221 --> 00:36:11,290 And remember, there was no such thing 657 00:36:11,324 --> 00:36:13,125 as a search engine or a computer. 658 00:36:13,159 --> 00:36:16,362 All Halley had were his books and his mind. 659 00:36:16,396 --> 00:36:18,197 Now here comes the hard part, 660 00:36:18,231 --> 00:36:21,200 Halley had to take the observations made for each comet 661 00:36:21,234 --> 00:36:25,337 and find the shape of its actual path through space. 662 00:36:25,372 --> 00:36:27,439 No one else but Newton had yet attempted 663 00:36:27,474 --> 00:36:30,776 to apply his new set of laws to an astronomical question. 664 00:36:30,810 --> 00:36:34,113 In an arduous tour de force of mathematical brilliance, 665 00:36:34,147 --> 00:36:38,484 Halley discovered that comets were bound to the Sun 666 00:36:38,518 --> 00:36:40,753 in long elliptical orbits. 667 00:36:44,557 --> 00:36:49,194 And he was the first to know that the comets seen in 1531, 668 00:36:49,229 --> 00:36:55,067 1607, and 1682... 669 00:36:55,101 --> 00:36:57,069 were one and the same-- 670 00:36:57,103 --> 00:37:00,305 a single comet that returned every 76 years. 671 00:37:00,340 --> 00:37:03,675 In a stunning example of true pattern recognition, 672 00:37:03,710 --> 00:37:06,678 he predicted it would be seen again 673 00:37:06,713 --> 00:37:08,881 more than 50 years in the future. 674 00:37:10,583 --> 00:37:13,652 For millennia, comets had been props for mystics, 675 00:37:13,686 --> 00:37:18,257 who considered them to be merely omens of human events. 676 00:37:18,291 --> 00:37:20,059 Halley shattered their monopoly, 677 00:37:20,093 --> 00:37:22,528 beating them at their own game, 678 00:37:22,562 --> 00:37:26,198 a game that no scientist had ever played before... 679 00:37:26,232 --> 00:37:27,900 prophecy. 680 00:37:27,934 --> 00:37:30,235 And he did not hedge his bet. 681 00:37:30,270 --> 00:37:31,837 Like Babe Ruth predicting 682 00:37:31,871 --> 00:37:34,673 where his next home run would land in the stands, 683 00:37:34,708 --> 00:37:37,609 Halley stated flatly that the comet would return 684 00:37:37,644 --> 00:37:42,214 at the end of 1758, from a particular part of the sky, 685 00:37:42,248 --> 00:37:44,516 following a specific path. 686 00:37:44,551 --> 00:37:47,286 There is hardly a prophecy attempted by the mystics 687 00:37:47,320 --> 00:37:50,456 that ever even strives for comparable precision. 688 00:38:08,568 --> 00:38:10,603 That's Halley's Comet. 689 00:38:10,637 --> 00:38:13,038 Out here at the edge of the solar system, 690 00:38:13,073 --> 00:38:14,440 it doesn't look like much. 691 00:38:14,474 --> 00:38:17,943 Just a big hunk of ice and rock in space. 692 00:38:17,978 --> 00:38:19,979 That's because beyond the orbit of Neptune, 693 00:38:20,013 --> 00:38:22,481 nearly five billion kilometers from the Sun, 694 00:38:22,515 --> 00:38:24,984 comets lead very quiet lives. 695 00:38:27,487 --> 00:38:30,756 As it reaches the far end of its orbit, 696 00:38:30,790 --> 00:38:33,759 it'll slow down till the Sun allows it to go no farther. 697 00:38:33,793 --> 00:38:38,464 Then it will begin its long fall back to the inner solar system. 698 00:38:38,498 --> 00:38:42,101 Halley's comet is in free fall around the Sun. 699 00:38:42,135 --> 00:38:45,471 Everything in our solar system-- the Earth, the Moon, 700 00:38:45,505 --> 00:38:47,573 the other planets, comets, asteroids, 701 00:38:47,607 --> 00:38:50,809 all of them are falling around the Sun. 702 00:38:50,844 --> 00:38:53,846 Gravity pulls the planets towards the Sun, 703 00:38:53,880 --> 00:38:55,781 but because of their orbital momentum, 704 00:38:55,815 --> 00:38:59,818 they keep moving around the Sun, never falling into it. 705 00:39:03,823 --> 00:39:05,958 Robert Hooke had died years before, 706 00:39:05,992 --> 00:39:08,761 having ruined his health with some bad habits... 707 00:39:08,795 --> 00:39:12,798 daily doses of wormwood, opium, mercury. 708 00:39:12,832 --> 00:39:15,968 A few months later, Newton was elected to replace him 709 00:39:16,002 --> 00:39:18,204 as president of the Royal Society. 710 00:39:18,238 --> 00:39:20,973 It is said that a portrait of Hooke 711 00:39:21,007 --> 00:39:23,776 once hung on these walls. 712 00:39:23,810 --> 00:39:28,314 Halley lived on to accomplish many more astonishing feats. 713 00:39:28,348 --> 00:39:32,985 He worked right up to his death at age 85. 714 00:39:33,019 --> 00:39:36,522 His final act was to call for a glass of wine. 715 00:39:36,556 --> 00:39:38,891 He downed it with pleasure... 716 00:39:38,925 --> 00:39:41,060 and breathed his last breath. 717 00:39:46,199 --> 00:39:50,169 Some believe that it was on a night like this 718 00:39:50,203 --> 00:39:53,172 that Isaac Newton finally took his revenge 719 00:39:53,206 --> 00:39:55,040 against Robert Hooke. 720 00:40:09,589 --> 00:40:12,057 But Halley's prophecy was not forgotten. 721 00:40:12,092 --> 00:40:13,659 50 years later, 722 00:40:13,693 --> 00:40:16,328 as the time of the predicted return approached, 723 00:40:16,363 --> 00:40:18,097 the world's astronomers vied 724 00:40:18,131 --> 00:40:21,000 to be the first to catch sight of his comet. 725 00:40:21,034 --> 00:40:22,601 They weren't disappointed. 726 00:40:22,636 --> 00:40:26,872 It's been welcomed back every 76 years since. 727 00:40:26,907 --> 00:40:30,276 When Halley's Comet returns to our skies, 728 00:40:30,310 --> 00:40:33,345 sunlight will warm up the ice on its surface, 729 00:40:33,380 --> 00:40:35,347 once again setting loose 730 00:40:35,382 --> 00:40:39,285 the dust and gases trapped within. 731 00:40:41,254 --> 00:40:43,722 Halley's Comet most recently visited our neighborhood 732 00:40:43,757 --> 00:40:46,592 back in 1986. 733 00:40:46,626 --> 00:40:49,695 And if you're seeing this in 2061, 734 00:40:49,729 --> 00:40:51,664 then you'll know it's back. 735 00:40:54,234 --> 00:40:56,068 May you feel the wonder of all those 736 00:40:56,102 --> 00:40:58,470 who came before you... 737 00:40:58,505 --> 00:41:00,472 and none of the fear. 738 00:41:00,507 --> 00:41:04,109 Newton's laws made it possible for Edmond Halley 739 00:41:04,144 --> 00:41:06,812 to see some 50 years into the future 740 00:41:06,846 --> 00:41:09,815 and predict the behavior of a single comet. 741 00:41:09,849 --> 00:41:13,152 Scientists have been using these laws ever since, 742 00:41:13,186 --> 00:41:16,055 opening the way to the Moon 743 00:41:16,089 --> 00:41:19,091 and even beyond our solar system. 744 00:41:19,125 --> 00:41:21,860 The baby in the basket is learning to walk... 745 00:41:28,335 --> 00:41:30,870 and to know the cosmos. 746 00:41:34,975 --> 00:41:36,308 Which brings me 747 00:41:36,343 --> 00:41:38,077 to one last prophecy. 748 00:41:38,111 --> 00:41:41,247 Using nothing more than Newton's laws of gravitation, 749 00:41:41,281 --> 00:41:43,949 we astronomers can confidently predict 750 00:41:43,984 --> 00:41:46,252 that several billion years from now, 751 00:41:46,286 --> 00:41:48,988 our home galaxy, the Milky Way, 752 00:41:49,022 --> 00:41:53,325 will merge with our neighboring galaxy Andromeda. 753 00:41:54,895 --> 00:41:57,096 Because the distances between the stars 754 00:41:57,130 --> 00:41:59,465 are so great compared to their sizes, 755 00:41:59,499 --> 00:42:02,935 few if any stars in either galaxy will actually collide. 756 00:42:02,969 --> 00:42:05,871 Any life on the worlds of that far-off future 757 00:42:05,906 --> 00:42:09,842 should be safe, but they would be treated to an amazing, 758 00:42:09,876 --> 00:42:13,846 billion-year-long light show... 759 00:42:13,880 --> 00:42:17,516 a dance of a half a trillion stars... 760 00:42:17,551 --> 00:42:22,054 to music first heard on one little world 761 00:42:22,088 --> 00:42:26,825 by a man who had but one true friend.