1 00:00:44,444 --> 00:00:46,878 SAGAN: In the vastness of the cosmos... 2 00:00:47,080 --> 00:00:50,106 ...there must be other civilizations far older... 3 00:00:50,316 --> 00:00:52,181 ...and more advanced than ours. 4 00:00:52,385 --> 00:00:56,253 So shouldn't we have been visited? Shouldn't there be... 5 00:00:56,456 --> 00:01:00,256 ...alien ships in the skies of Earth? 6 00:01:01,594 --> 00:01:03,721 There's nothing impossible in this idea. 7 00:01:03,930 --> 00:01:06,831 And no one would be happier than me if we were visited. 8 00:01:07,033 --> 00:01:10,059 But has it happened in fact? 9 00:01:10,270 --> 00:01:14,832 What counts is not what's plausible, not what we'd like to believe... 10 00:01:15,041 --> 00:01:17,407 ...not what one or two witnesses claim. 11 00:01:17,610 --> 00:01:20,477 But only what is supported by hard evidence... 12 00:01:20,680 --> 00:01:23,410 ...rigorously and skeptically examined. 13 00:01:23,616 --> 00:01:28,553 Extraordinary claims require extraordinary evidence. 14 00:01:32,525 --> 00:01:37,462 Since 1947, there have been hundreds of thousands of reports of UFOs: 15 00:01:37,831 --> 00:01:40,698 Unidentified flying objects. 16 00:01:40,900 --> 00:01:42,299 This subject has... 17 00:01:42,502 --> 00:01:46,495 ...more to do with religion and superstition than with science. 18 00:01:46,706 --> 00:01:50,608 Let's consider one of the most famous accounts of a supposed encounter... 19 00:01:50,810 --> 00:01:52,778 ...with alien beings. 20 00:01:53,146 --> 00:01:55,444 On September 19, 1961... 21 00:01:55,648 --> 00:01:59,311 ...an American couple was driving home through New Hampshire. 22 00:01:59,686 --> 00:02:01,153 What's the matter, Delsey? 23 00:02:02,989 --> 00:02:05,787 SAGAN: They were returning along a lonely road, late at night... 24 00:02:05,992 --> 00:02:08,290 ...from a vacation in Canada. 25 00:02:09,963 --> 00:02:13,558 Remember, we have only their word for what happened next. 26 00:02:14,734 --> 00:02:17,498 (TUNES RADIO) 27 00:02:18,505 --> 00:02:20,473 (STATIC FROM RADIO) 28 00:02:20,940 --> 00:02:22,840 I'm only getting static. 29 00:02:25,078 --> 00:02:27,342 You still don't believe it, do you? 30 00:02:27,947 --> 00:02:31,178 No, I don't. There must be a reasonable explanation. 31 00:02:31,384 --> 00:02:32,442 Oh! 32 00:02:32,652 --> 00:02:35,143 SAGAN: They had observed, so they said... 33 00:02:35,355 --> 00:02:37,880 ...a strange moving light in the sky. 34 00:02:38,091 --> 00:02:41,390 By definition, an unidentified flying object. 35 00:02:41,761 --> 00:02:44,025 It seemed to follow them for miles. 36 00:02:45,198 --> 00:02:46,165 Easy there. 37 00:02:46,366 --> 00:02:48,300 What's the matter with that dog? 38 00:02:49,302 --> 00:02:51,327 (HUMMING NOISE) 39 00:02:51,538 --> 00:02:53,096 What's that sound? 40 00:02:57,010 --> 00:02:58,170 I don't know. 41 00:02:58,578 --> 00:03:02,776 After a time, the lighting patterns on the UFO changed. 42 00:03:05,118 --> 00:03:07,678 It appeared to land. 43 00:03:11,291 --> 00:03:12,258 What the... 44 00:03:14,827 --> 00:03:18,092 It blocked the road, preventing them from driving on. 45 00:03:23,403 --> 00:03:27,533 They said they saw mouthless creatures approaching... 46 00:03:27,740 --> 00:03:30,641 ...who were not exactly human. 47 00:03:30,977 --> 00:03:32,410 Barney! 48 00:03:32,612 --> 00:03:34,204 Barney, what is that? 49 00:03:36,583 --> 00:03:40,178 At this point, the story becomes still stranger. 50 00:03:40,386 --> 00:03:44,584 They lost all recollection of what happened in the next few hours. 51 00:03:48,094 --> 00:03:50,028 But weeks later, they said... 52 00:03:50,230 --> 00:03:54,564 ...they recalled some details and discussed the experience with others. 53 00:03:58,871 --> 00:04:02,170 26 months later, under hypnosis... 54 00:04:02,442 --> 00:04:04,910 ...they reported that a UFO had landed... 55 00:04:05,111 --> 00:04:07,579 ...and that the crew had emerged. 56 00:04:17,857 --> 00:04:22,794 They were captured, they said, and taken aboard the craft. 57 00:04:32,171 --> 00:04:33,331 (WHINES) 58 00:04:39,846 --> 00:04:43,714 That was the story told by Betty and Barney Hill. 59 00:04:43,916 --> 00:04:47,613 Virtually all scientists who've studied it are skeptical. 60 00:04:47,820 --> 00:04:52,348 But UFO enthusiasts think the Hill case is a classic example... 61 00:04:52,558 --> 00:04:55,891 ...of a "close encounter of the third kind." 62 00:04:56,095 --> 00:04:59,326 Why? What makes it so special? 63 00:05:01,000 --> 00:05:03,161 While on board, Betty had noticed... 64 00:05:03,369 --> 00:05:06,634 ...a book written in an unknown hieroglyphic writing. 65 00:05:06,839 --> 00:05:10,297 She was also shown a strange window through which she could see... 66 00:05:10,510 --> 00:05:13,707 ...a glowing pattern of dots connected with lines. 67 00:05:13,913 --> 00:05:16,404 It was, they told her, a star map... 68 00:05:16,616 --> 00:05:19,881 ...displaying the routes of interstellar commerce. 69 00:05:20,086 --> 00:05:23,385 Afterwards, they were released and permitted to return home. 70 00:05:23,589 --> 00:05:25,682 Or at least, this is their story. 71 00:05:26,326 --> 00:05:29,591 Believers find this compelling, or at least plausible... 72 00:05:29,796 --> 00:05:32,390 ...chiefly because of the alleged star map. 73 00:05:32,965 --> 00:05:35,934 Here's how Betty said it looked. 74 00:05:36,135 --> 00:05:38,763 Why would we take this seriously? 75 00:05:38,971 --> 00:05:43,772 Because here is a real map widely publicized by UFO enthusiasts... 76 00:05:43,976 --> 00:05:48,242 ...of 15 selected nearby stars, including the sun... 77 00:05:48,514 --> 00:05:52,109 ...as seen from one particular vantage point in space. 78 00:05:52,318 --> 00:05:53,945 This map includes stars... 79 00:05:54,620 --> 00:05:57,350 ...that were first cataloged several years after... 80 00:05:57,557 --> 00:06:01,186 ...Betty Hill recalled what she says she saw in the alien ship. 81 00:06:01,394 --> 00:06:03,589 Her map required, we are told... 82 00:06:03,796 --> 00:06:06,230 ...information that wasn't available on Earth. 83 00:06:07,200 --> 00:06:10,636 There is a resemblance between the two maps, but that's because... 84 00:06:10,837 --> 00:06:13,601 ...the lines corresponding to navigation routes... 85 00:06:13,806 --> 00:06:17,902 ...have been copied from the Hill map onto the real star map. 86 00:06:18,244 --> 00:06:22,544 If we were to substitute some other set of lines... 87 00:06:22,749 --> 00:06:26,412 ...for the Hill lines, we find that the eye suddenly is biased... 88 00:06:26,619 --> 00:06:30,111 ...against seeing any agreement between the two maps at all. 89 00:06:31,290 --> 00:06:36,159 To make an objective test, however, let's remove the lines altogether. 90 00:06:38,531 --> 00:06:41,500 And then there's very little resemblance left. 91 00:06:41,701 --> 00:06:43,328 But these particular stars... 92 00:06:43,536 --> 00:06:46,835 ...are selected from a large catalog of star positions. 93 00:06:47,039 --> 00:06:50,008 Our vantage point is also selected to make the best... 94 00:06:50,209 --> 00:06:52,677 ...possible fit with the Hill map. 95 00:06:52,879 --> 00:06:56,474 If you can pick and choose from a large number of stars... 96 00:06:56,682 --> 00:06:58,980 ...viewed from any vantage point in space... 97 00:06:59,185 --> 00:07:03,246 ...you can always find a resemblance to the pattern you're looking for. 98 00:07:03,456 --> 00:07:05,549 I'm surprised that nobody found... 99 00:07:05,758 --> 00:07:08,784 ...a better fit to the Hill map. 100 00:07:10,263 --> 00:07:15,030 The Hills' own psychiatrist described their story as a kind of dream. 101 00:07:15,234 --> 00:07:19,295 There's no corroborating evidence. The star map argument is worthless. 102 00:07:19,505 --> 00:07:22,474 And yet this is one of the best attested cases... 103 00:07:22,675 --> 00:07:25,007 ...of UFO close encounters. 104 00:07:25,211 --> 00:07:27,008 For all I know, we're visited... 105 00:07:27,213 --> 00:07:31,149 ...by a different extraterrestrial civilization every second Tuesday. 106 00:07:31,350 --> 00:07:34,581 But there's no support for this appealing idea. 107 00:07:34,787 --> 00:07:39,019 The extraordinary claims are not supported by extraordinary evidence. 108 00:07:40,560 --> 00:07:43,893 There are curious daylight photos of UFOs. 109 00:07:46,466 --> 00:07:48,457 Some look suspiciously like... 110 00:07:48,668 --> 00:07:51,796 ...hats or hubcaps thrown into the air. 111 00:07:52,004 --> 00:07:54,131 Photos can be faked. 112 00:07:59,178 --> 00:08:01,976 More common are unidentified lights at night. 113 00:08:02,181 --> 00:08:03,341 They're often aircraft. 114 00:08:03,549 --> 00:08:07,212 But if we can't identify a light, that doesn't make it a spaceship. 115 00:08:12,492 --> 00:08:15,052 Here's a movie of what you might think is a UFO. 116 00:08:15,261 --> 00:08:18,196 Actually it's a piece of an asteroid burning up... 117 00:08:18,397 --> 00:08:20,729 ...as it enters the Earth's atmosphere. 118 00:08:27,406 --> 00:08:31,740 Most reports of UFOs turn out to be something else, like... 119 00:08:31,944 --> 00:08:36,677 ...the refracted image of a planet or re-entry of an artificial satellite. 120 00:08:36,883 --> 00:08:40,512 Some are psychological aberrations. Some are hoaxes. 121 00:08:40,753 --> 00:08:44,587 Never is there any compelling physical evidence... 122 00:08:44,790 --> 00:08:48,157 ...a detailed close-up photograph of a strange spacecraft... 123 00:08:48,361 --> 00:08:51,524 ...or a small device of extraterrestrial manufacture... 124 00:08:51,731 --> 00:08:54,666 ...or a book written in alien hieroglyphics. 125 00:08:54,867 --> 00:08:55,925 Never. 126 00:08:56,135 --> 00:09:00,731 There are reports of such things, but never the things themselves. 127 00:09:03,309 --> 00:09:07,939 The search for alien civilizations retains its importance despite... 128 00:09:08,147 --> 00:09:11,173 ...the striking failure of the UFO evidence. 129 00:09:11,384 --> 00:09:14,376 Most astronomers consider extraterrestrial life... 130 00:09:14,587 --> 00:09:18,648 ...a subject worthy of vigorous, if cautious, pursuit. 131 00:09:18,858 --> 00:09:22,988 For myself, I find something irresistible in the idea of... 132 00:09:23,195 --> 00:09:26,562 ...discovering a token, maybe a simple inscription... 133 00:09:26,766 --> 00:09:31,703 ...which would provide the key to understanding an alien civilization. 134 00:09:32,071 --> 00:09:35,939 This is an appeal we humans have felt before. 135 00:09:52,291 --> 00:09:53,519 In 1801... 136 00:09:53,726 --> 00:09:58,663 ...a famous physicist was governor of the French province of Isère. 137 00:10:00,833 --> 00:10:03,563 His name was Joseph Fourier. 138 00:10:04,971 --> 00:10:07,599 On an inspection of the schools in his province... 139 00:10:07,807 --> 00:10:10,742 ...Fourier discovered an exceptional 11-year-old boy: 140 00:10:10,943 --> 00:10:13,002 Jean Francois Champollion. 141 00:10:17,550 --> 00:10:21,748 The boy's precocious intellect and remarkable flair for languages... 142 00:10:21,954 --> 00:10:25,014 ...had earned him the admiration of local scholars. 143 00:10:25,224 --> 00:10:27,886 Fourier too was impressed. 144 00:10:32,598 --> 00:10:35,761 What Champollion first saw in Fourier's house... 145 00:10:35,968 --> 00:10:37,868 ...determined the course of his life... 146 00:10:38,070 --> 00:10:41,767 ...and unlocked the secrets of an alien civilization. 147 00:10:44,210 --> 00:10:47,873 Fourier had recently participated, as one of many scientists... 148 00:10:48,080 --> 00:10:50,742 ...in Napoleon's expedition to the Middle East. 149 00:10:50,950 --> 00:10:55,649 He had been in charge of cataloging the astronomical monuments of Egypt. 150 00:10:57,790 --> 00:11:00,884 The boy was entranced by Fourier's collection... 151 00:11:01,093 --> 00:11:03,357 ...of ancient Egyptian artifacts: 152 00:11:03,562 --> 00:11:06,497 The mysterious fragments of a lost world. 153 00:11:15,274 --> 00:11:18,300 France at this time was flooded with such artifacts... 154 00:11:18,511 --> 00:11:20,240 ...plundered by Napoleon... 155 00:11:20,446 --> 00:11:25,042 ...and now arousing intense interest among scholars and the general public. 156 00:11:36,796 --> 00:11:38,388 His attention was caught... 157 00:11:38,597 --> 00:11:42,033 ...by a specimen of Egyptian hieroglyphics. 158 00:11:54,380 --> 00:11:56,439 "What do they mean? " he asked. 159 00:11:57,116 --> 00:11:59,744 "Nobody knows," was Fourier's reply. 160 00:12:00,820 --> 00:12:03,220 Then and there, Champollion resolved... 161 00:12:03,422 --> 00:12:06,550 ...he would understand this language no one could read... 162 00:12:06,759 --> 00:12:10,695 ...he would decode the messages from another world and another time. 163 00:12:10,896 --> 00:12:15,765 He became a superb linguist and immersed himself in the hieroglyphics. 164 00:12:21,874 --> 00:12:26,436 Fourier edited the illustrated description of Napoleon's expedition. 165 00:12:26,645 --> 00:12:29,944 The young Champollion studied it hungrily. 166 00:12:31,517 --> 00:12:32,882 To the people of Europe... 167 00:12:33,085 --> 00:12:38,022 ...these exotic images revealed an utterly alien civilization... 168 00:12:38,357 --> 00:12:43,294 ...a world of towering monuments and magical names. 169 00:12:43,662 --> 00:12:45,323 Dendera. 170 00:12:45,531 --> 00:12:47,089 Karnak. 171 00:12:47,500 --> 00:12:48,933 Luxor. 172 00:12:51,637 --> 00:12:56,574 Every illustration was a riddle posed by the past to the present. 173 00:13:02,548 --> 00:13:06,985 And among them were pictures of something called the Rosetta Stone... 174 00:13:09,455 --> 00:13:14,358 ...and portraits of the people who lived among the ruins of the pharaohs. 175 00:13:17,997 --> 00:13:21,489 Egypt became the land of Champollion's dreams. 176 00:13:23,502 --> 00:13:25,561 But it was not until 1828... 177 00:13:25,771 --> 00:13:29,036 ...27 years after his fateful visit with Fourier... 178 00:13:29,241 --> 00:13:32,677 ...that Champollion first set foot in Egypt. 179 00:13:38,684 --> 00:13:43,417 With his companions, Champollion chartered boats in Cairo... 180 00:13:43,622 --> 00:13:46,557 ...and sailed slowly upstream... 181 00:13:46,759 --> 00:13:50,217 ...following the course of the Nile. 182 00:14:03,342 --> 00:14:05,833 It was a journey of many weeks... 183 00:14:06,045 --> 00:14:10,038 ...which Champollion recorded in extraordinary detail. 184 00:14:20,292 --> 00:14:23,284 This was an expedition through time... 185 00:14:23,495 --> 00:14:26,055 ...a voyage across the centuries... 186 00:14:26,265 --> 00:14:27,857 ...to another world. 187 00:14:36,008 --> 00:14:37,908 Champollion, as an adult... 188 00:14:38,110 --> 00:14:41,978 ...had worked out a brilliant decipherment of the hieroglyphics. 189 00:14:42,181 --> 00:14:46,117 A word, incidentally, that means "sacred carvings." 190 00:14:48,587 --> 00:14:51,021 Now Champollion was making a pilgrimage... 191 00:14:51,223 --> 00:14:55,990 ...to the scene of ancient mysteries he had been the first to understand. 192 00:15:24,623 --> 00:15:26,113 Champollion wrote: 193 00:15:26,325 --> 00:15:31,160 "The evening of the 16th, we finally arrived at Dendera. 194 00:15:38,070 --> 00:15:41,403 We were only an hour away from the temples. 195 00:15:44,576 --> 00:15:46,840 Could we resist the temptation? 196 00:15:47,046 --> 00:15:50,379 I ask the coldest of you mortals! 197 00:15:53,953 --> 00:15:57,787 To dine and leave immediately were the orders of the moment. 198 00:16:04,530 --> 00:16:09,126 Alone and without guides, we crossed the fields. 199 00:16:12,738 --> 00:16:16,435 Presuming that the temples were in a straight line from our boat... 200 00:16:16,642 --> 00:16:20,408 ...we walked thus for an hour and a half without finding anything. 201 00:16:20,612 --> 00:16:23,638 We discovered a man who put us on the correct route... 202 00:16:23,849 --> 00:16:27,182 ...and ended up walking with us with good graces. 203 00:16:33,659 --> 00:16:37,254 The temple appeared to us at last. 204 00:16:47,740 --> 00:16:51,437 I shall not try to describe the impression which the porches... 205 00:16:51,643 --> 00:16:54,476 ...and above all, the portico made on us. 206 00:16:57,049 --> 00:16:59,609 We stayed there two hours in ecstasy... 207 00:16:59,818 --> 00:17:02,981 ...running through the huge rooms and trying to read... 208 00:17:03,188 --> 00:17:06,248 ...the exterior inscriptions in the moonlight." 209 00:17:12,865 --> 00:17:15,629 It was with no small rapture that Champollion... 210 00:17:15,834 --> 00:17:20,328 ...entered the secret places of the temple and scanned the words... 211 00:17:20,539 --> 00:17:23,838 ...that had waited patiently through half a million nights... 212 00:17:24,043 --> 00:17:25,567 ...for a reader. 213 00:17:29,048 --> 00:17:31,846 To his brother, Champollion wrote of his joy... 214 00:17:32,051 --> 00:17:36,044 ...in confirming that he could understand the writing on these walls. 215 00:17:37,756 --> 00:17:39,621 "I am now proud," he said... 216 00:17:39,825 --> 00:17:43,090 "...that having followed the course of the Nile... 217 00:17:43,295 --> 00:17:47,629 ...I have the right to announce there is nothing to modify in our letter... 218 00:17:47,833 --> 00:17:50,199 ...on the alphabet of hieroglyphics. 219 00:17:58,877 --> 00:18:00,708 Our alphabet is good. 220 00:18:00,913 --> 00:18:04,314 It is applicable with the same success, first of all... 221 00:18:04,516 --> 00:18:06,848 ...in Egyptian monuments of the Roman epoch... 222 00:18:07,052 --> 00:18:08,952 ...and, which is more interesting... 223 00:18:09,154 --> 00:18:13,181 ...to the inscriptions on all temples, palaces and tombs... 224 00:18:13,392 --> 00:18:15,587 ...of the Pharaonic epoch." 225 00:18:20,799 --> 00:18:25,736 Champollion was overwhelmed by the grandeur which surrounded him. 226 00:18:26,538 --> 00:18:28,096 "It is the union," he said... 227 00:18:28,307 --> 00:18:32,573 "...of grace and majesty in the highest degree. 228 00:18:32,778 --> 00:18:34,871 We in Europe are only dwafts. 229 00:18:35,080 --> 00:18:39,107 No nation, ancient or modern, has conceived the art of architecture... 230 00:18:39,318 --> 00:18:43,152 ...on such a sublime, great and imposing style... 231 00:18:43,355 --> 00:18:45,050 ...as the ancient Egyptians. 232 00:18:45,257 --> 00:18:49,887 They ordered everything to be done for people who are 100 feet high." 233 00:18:57,202 --> 00:19:01,070 This is the great temple of Karnak... 234 00:19:01,273 --> 00:19:02,672 ...in upper Egypt... 235 00:19:02,875 --> 00:19:07,437 ...continuously constructed over a period of more than 2,000 years... 236 00:19:07,646 --> 00:19:09,773 ...until the time of Ptolemy. 237 00:19:09,982 --> 00:19:12,450 It was here Champollion wrote: 238 00:19:12,651 --> 00:19:17,554 "That all the Pharaonic magnificence appeared to me." 239 00:19:17,756 --> 00:19:19,917 What he had seen elsewhere, he said... 240 00:19:20,125 --> 00:19:21,922 ..."Seemed to me, miserable... 241 00:19:22,127 --> 00:19:26,530 ...compared with the colossal conceptions around me." 242 00:19:49,521 --> 00:19:52,388 On these walls and columns at Karnak... 243 00:19:52,591 --> 00:19:54,889 ...at Dendera and everywhere else in Egypt... 244 00:19:55,093 --> 00:19:58,460 ...Champollion found that he could read inscriptions... 245 00:19:58,664 --> 00:20:02,191 ...that his decipherment of a few years earlier had been correct. 246 00:20:02,401 --> 00:20:04,733 But how had he figured it out? 247 00:20:07,739 --> 00:20:11,573 Many had tried and failed to read the hieroglyphics. 248 00:20:11,777 --> 00:20:16,612 A group of scholars thought they were a picture code full of metaphors... 249 00:20:16,815 --> 00:20:21,616 ...mostly about eyeballs, wavy lines and animals. 250 00:20:21,820 --> 00:20:26,621 Birds, especially birds, lots of birds. 251 00:20:29,461 --> 00:20:34,398 Some deduced that the Egyptians had been colonists from China. 252 00:20:34,800 --> 00:20:37,860 There were those who deduced it the other way around. 253 00:20:42,207 --> 00:20:46,769 There's one who, from one look at the Rosetta Stone, deduced its meaning. 254 00:20:46,979 --> 00:20:49,641 He said that the quickness of his decipherment... 255 00:20:49,848 --> 00:20:53,340 ...enabled him "to avoid the systematic errors... 256 00:20:53,552 --> 00:20:57,215 ...which invariably arise from prolonged reflection." 257 00:20:57,422 --> 00:21:01,518 You get better results, he's saying, if you don't think about it too much. 258 00:21:01,727 --> 00:21:05,925 As in the search for extraterrestrial intelligence today... 259 00:21:06,131 --> 00:21:09,259 ...the unbridled speculation by amateurs... 260 00:21:09,468 --> 00:21:12,995 ...served to frighten many professionals right out of the field. 261 00:21:23,582 --> 00:21:25,379 Champollion was not frightened. 262 00:21:25,584 --> 00:21:28,212 He was also not distracted by the idea... 263 00:21:28,420 --> 00:21:31,150 ...of hieroglyphs as pictorial metaphors. 264 00:21:31,356 --> 00:21:32,914 Instead... 265 00:21:33,125 --> 00:21:37,789 ...using the insights of a brilliant English physicist, Thomas Young... 266 00:21:37,996 --> 00:21:40,089 ...he proceeded something like this: 267 00:21:40,699 --> 00:21:45,033 This is an exact replica of the Rosetta Stone. 268 00:21:45,237 --> 00:21:48,172 The original had been found in the year 1799... 269 00:21:48,373 --> 00:21:51,137 ...by a French soldier working on the fortifications... 270 00:21:51,343 --> 00:21:54,278 ...of the Nile delta town of Rashid... 271 00:21:54,479 --> 00:21:58,643 ...which the Europeans, in their persistence not to learn Arabic... 272 00:21:58,850 --> 00:22:00,283 ...called "Rosetta." 273 00:22:00,485 --> 00:22:05,252 It had been part of an ancient temple which had been torn down. 274 00:22:05,524 --> 00:22:08,687 If we look at it, we see that it clearly... 275 00:22:08,894 --> 00:22:12,694 ...represents the same text in three different languages. 276 00:22:13,265 --> 00:22:16,234 Up at the top, ancient Egyptian hieroglyphics. 277 00:22:16,435 --> 00:22:18,995 In the middle, a kind of cursive... 278 00:22:19,204 --> 00:22:21,695 ...and later hieroglyphic called "Demotic." 279 00:22:21,907 --> 00:22:26,071 And down at the bottom, the key to the enterprise: Greek. 280 00:22:26,445 --> 00:22:30,381 Champollion could read ancient Greek, he was a superb linguist... 281 00:22:30,582 --> 00:22:34,609 ...and discovered that this stone had been inscribed... 282 00:22:34,820 --> 00:22:36,651 ...to commemorate the coronation... 283 00:22:36,855 --> 00:22:40,052 ...of King Ptolemy V Epiphanes... 284 00:22:40,258 --> 00:22:44,752 ...in the spring of the year 196 B.C. 285 00:22:45,230 --> 00:22:50,133 As expected, the Greek text includes many references to King Ptolemy. 286 00:22:50,335 --> 00:22:51,893 Here you can see it. 287 00:22:52,104 --> 00:22:56,438 "Ptolemaeus." 288 00:22:57,642 --> 00:23:01,635 In roughly the same positions but in the hieroglyphic text... 289 00:23:02,214 --> 00:23:07,083 ...are these ovals or "cartouches" as they are called. 290 00:23:07,285 --> 00:23:10,812 And if this cartouche really means "Ptolemy"... 291 00:23:11,022 --> 00:23:15,959 ...the individual hieroglyphs are not likely to be pictograms or metaphors. 292 00:23:16,161 --> 00:23:20,120 Much more likely, they're letters or at least syllables. 293 00:23:20,332 --> 00:23:22,766 Champollion had the presence of mind... 294 00:23:22,968 --> 00:23:26,199 ...to count up the number of Greek words... 295 00:23:26,405 --> 00:23:29,568 ...and the number of individual hieroglyphics... 296 00:23:29,775 --> 00:23:32,039 ...in what are presumably equivalent texts. 297 00:23:32,244 --> 00:23:36,510 He found that the number of individual hieroglyphs... 298 00:23:36,715 --> 00:23:39,912 ...is much larger than the number of Greek words... 299 00:23:40,118 --> 00:23:44,054 ...again implying that the hieroglyphs are mainly letters and syllables. 300 00:23:44,256 --> 00:23:48,886 But which hieroglyphs correspond to which letters? 301 00:23:49,094 --> 00:23:53,326 Fortunately, Champollion had available a kind of second Rosetta Stone... 302 00:23:53,532 --> 00:23:57,491 ...an obelisk which had been excavated at the temple of Philae... 303 00:23:57,702 --> 00:24:01,331 ...and which had inscribed upon it... 304 00:24:01,540 --> 00:24:05,909 ...cartouches representing the hieroglyphic equivalent... 305 00:24:06,111 --> 00:24:10,013 ...of another Greek name: Cleopatra. 306 00:24:10,782 --> 00:24:15,014 So here we have the Cleopatra cartouche. 307 00:24:15,220 --> 00:24:18,587 And here, the Ptolemaeus cartouche. 308 00:24:18,790 --> 00:24:22,317 Here, we've turned it around, changing left to right... 309 00:24:22,527 --> 00:24:26,463 ...to right to left, and spread the hieroglyphs out so we see them all. 310 00:24:26,832 --> 00:24:31,166 Now, immediately we notice that there are some similarities. 311 00:24:31,369 --> 00:24:34,736 This first hieroglyph in Ptolemy is a kind of square. 312 00:24:34,940 --> 00:24:38,467 The fifth hieroglyph in Cleopatra is a square. 313 00:24:38,977 --> 00:24:42,105 But "Cleopatra"... 314 00:24:42,314 --> 00:24:44,748 Both of them seem to represent a "p." 315 00:24:44,950 --> 00:24:48,579 So Ptolemy and Cleopatra... 316 00:24:48,787 --> 00:24:51,187 ...both give us the same interpretation: 317 00:24:51,389 --> 00:24:54,017 A square is a "p." 318 00:24:54,326 --> 00:24:57,261 Likewise, the fourth hieroglyph... 319 00:24:57,462 --> 00:24:59,987 ...in Ptolemy is a lion. 320 00:25:00,198 --> 00:25:02,564 "P-t-o-I." 321 00:25:02,767 --> 00:25:07,431 Likewise, the second hieroglyph in Cleopatra is an "I." 322 00:25:08,240 --> 00:25:12,267 So again it's consistent. The pattern is emerging. 323 00:25:12,477 --> 00:25:16,174 Likewise, this rope or hangman's noose... 324 00:25:16,381 --> 00:25:19,145 ..."Ptolemy." It's an "o." 325 00:25:19,351 --> 00:25:22,013 "Cleopatra." It's an "o." 326 00:25:22,220 --> 00:25:26,418 And in this way, Champollion was able to assign... 327 00:25:27,425 --> 00:25:32,362 ...letters for each of the hieroglyphs we see here. 328 00:25:33,999 --> 00:25:35,967 "Ptolemaeus." 329 00:25:36,301 --> 00:25:38,496 And, likewise... 330 00:25:38,703 --> 00:25:42,434 ..."Cleopatra." 331 00:25:42,641 --> 00:25:45,769 The eagle is an "a." 332 00:25:46,478 --> 00:25:49,106 Notice there are two different symbols for "t." 333 00:25:49,314 --> 00:25:52,044 But in English, the same sort of thing, "f" and "ph." 334 00:25:52,951 --> 00:25:55,476 Champollion discovered that the hieroglyphics... 335 00:25:55,687 --> 00:25:57,780 ...were a simple substitution cipher. 336 00:25:57,989 --> 00:26:00,549 Now, there's other stuff in here. 337 00:26:00,759 --> 00:26:03,319 All the rest of this: What's that about? 338 00:26:03,528 --> 00:26:05,553 Well, he was later able to find out... 339 00:26:05,764 --> 00:26:08,494 ...this is a symbol called the "ankh" which means "life." 340 00:26:08,700 --> 00:26:12,295 There's a "pt." That's an "ah." It makes "Ptah"... 341 00:26:12,504 --> 00:26:13,801 ...name of a god. 342 00:26:14,005 --> 00:26:16,030 And the whole cartouche read: 343 00:26:16,241 --> 00:26:19,142 "Ptolemy, ever living... 344 00:26:19,344 --> 00:26:21,904 ...beloved of the god, Ptah." 345 00:26:22,113 --> 00:26:24,911 And the end of the "Cleopatra" is a short form... 346 00:26:25,116 --> 00:26:27,584 ...meaning "Daughter of Isis." 347 00:26:28,787 --> 00:26:32,223 So it turns out that Champollion's opponents were not wholly wrong. 348 00:26:32,424 --> 00:26:36,292 Some of the hieroglyphs, for example, the symbol "ankh"... 349 00:26:36,494 --> 00:26:40,328 ...which means life, are ideograms or pictograms. 350 00:26:40,532 --> 00:26:42,966 But the key to the enterprise... 351 00:26:43,168 --> 00:26:46,331 ...Champollion's success, rested on his realization... 352 00:26:46,538 --> 00:26:51,168 ...that the hieroglyphs were essentially letters and syllables. 353 00:26:51,376 --> 00:26:53,901 In retrospect, it sounds almost easy. 354 00:26:54,112 --> 00:26:58,674 But it took people hundreds of years before they figured it out. 355 00:27:00,085 --> 00:27:04,988 Champollion walked these halls and casually read the inscriptions... 356 00:27:05,190 --> 00:27:07,158 ...which had mystified everybody else. 357 00:27:07,359 --> 00:27:11,455 Answering the question he had posed as a child to Fourier: 358 00:27:11,663 --> 00:27:13,631 "What do they mean? " 359 00:27:14,265 --> 00:27:16,756 What a joy it must have been for him... 360 00:27:16,968 --> 00:27:21,905 ...to open this one-way communications channel with another civilization... 361 00:27:22,173 --> 00:27:26,974 ...to permit a culture which had been mute for millennia... 362 00:27:27,178 --> 00:27:31,444 ...to speak of its history, magic, medicine... 363 00:27:31,650 --> 00:27:35,211 ...religion, politics, philosophy. 364 00:27:48,867 --> 00:27:51,335 Today, we also are seeking messages... 365 00:27:51,536 --> 00:27:54,300 ...from an ancient and exotic civilization. 366 00:27:54,506 --> 00:27:56,565 A civilization hidden from us... 367 00:27:57,876 --> 00:28:01,277 ...not in time, but in space. 368 00:28:02,547 --> 00:28:07,007 Today, we are searching for a message from the stars. 369 00:28:07,218 --> 00:28:11,518 We have not found it so far. We have, as yet, no Champollion. 370 00:28:11,723 --> 00:28:13,122 But we are just beginning. 371 00:28:13,324 --> 00:28:18,227 Perhaps those who will decipher the first interstellar communications... 372 00:28:18,430 --> 00:28:23,333 ...are alive at this moment, somewhere on the planet Earth. 373 00:28:27,405 --> 00:28:30,738 Extraterrestrial beings will have a different biology... 374 00:28:30,942 --> 00:28:33,809 ...a different culture, a different language. 375 00:28:34,012 --> 00:28:36,879 How could we possibly understand their messages? 376 00:28:37,082 --> 00:28:40,950 Is there in any sense a cosmic Rosetta Stone? 377 00:28:43,221 --> 00:28:44,483 I believe there is. 378 00:28:44,689 --> 00:28:49,183 All the technical civilizations in the cosmos, no matter how different... 379 00:28:49,394 --> 00:28:51,658 ...must have one language in common: 380 00:28:51,863 --> 00:28:54,923 The language called "science." 381 00:28:57,035 --> 00:29:00,971 The laws of nature are everywhere the same. 382 00:29:03,908 --> 00:29:08,709 Every chemical element has a specific signature in the spectrum. 383 00:29:08,913 --> 00:29:12,906 So there are identical patterns in the light of a candle flame on Earth... 384 00:29:13,118 --> 00:29:16,019 ...and in the light of a distant galaxy. 385 00:29:18,389 --> 00:29:20,721 The spectra show not only... 386 00:29:20,925 --> 00:29:23,985 ...that the same chemical elements exist throughout space... 387 00:29:24,195 --> 00:29:28,325 ...but also that the same laws of quantum mechanics... 388 00:29:28,533 --> 00:29:30,194 ...govern atoms everywhere. 389 00:29:30,401 --> 00:29:32,392 Beings growing up on any world... 390 00:29:32,604 --> 00:29:36,165 ...must come to grips with the identical laws of nature. 391 00:29:38,943 --> 00:29:43,880 Galaxies billions of light-years distant evolve a spiral form. 392 00:29:44,149 --> 00:29:45,844 So does our own Milky Way. 393 00:29:46,050 --> 00:29:49,713 The same gravitational forces are at work. 394 00:29:50,555 --> 00:29:51,920 And on planets also: 395 00:29:52,123 --> 00:29:56,253 There are spiral storm systems on Jupiter. 396 00:29:58,163 --> 00:30:01,360 The same patterns are common on Earth. 397 00:30:03,334 --> 00:30:06,929 The intelligent beings on every world will, sooner or later... 398 00:30:07,138 --> 00:30:09,504 ...understand the laws of nature. 399 00:30:09,707 --> 00:30:12,073 Someday, perhaps soon... 400 00:30:12,277 --> 00:30:16,475 ...a message from the depths of space may arrive on our small world. 401 00:30:16,681 --> 00:30:18,615 If we wish to understand it... 402 00:30:18,817 --> 00:30:22,480 ...we first have to understand science. 403 00:30:29,694 --> 00:30:33,323 We do not expect an advanced technical civilization... 404 00:30:33,531 --> 00:30:36,295 ...on any other planet of our solar system. 405 00:30:39,137 --> 00:30:43,597 If they were only a little behind us, 10,000 years, say... 406 00:30:43,808 --> 00:30:46,834 ...they would have no advanced technology at all. 407 00:30:49,547 --> 00:30:51,344 If they're a little ahead of us... 408 00:30:51,549 --> 00:30:55,110 ...we who are already exploring the solar system... 409 00:30:55,320 --> 00:30:57,311 ...then they should be here by now. 410 00:30:58,289 --> 00:31:00,450 To communicate with other civilizations... 411 00:31:00,658 --> 00:31:03,684 ...our technology must reach across not merely... 412 00:31:03,895 --> 00:31:06,329 ...interplanetary distances... 413 00:31:06,531 --> 00:31:09,329 ...but interstellar distances. 414 00:31:13,605 --> 00:31:15,903 Ideally, the method should be inexpensive. 415 00:31:16,107 --> 00:31:21,044 A huge amount of information could be sent and received at little cost. 416 00:31:23,448 --> 00:31:24,415 It should be fast... 417 00:31:24,616 --> 00:31:28,484 ...so an interstellar dialogue is eventually possible. 418 00:31:29,454 --> 00:31:30,614 It ought to be obvious... 419 00:31:30,822 --> 00:31:34,724 ...so that any technical civilization, no matter its evolutionary path... 420 00:31:34,926 --> 00:31:37,087 ...will discover it early. 421 00:31:39,163 --> 00:31:41,927 Surprisingly, there is such a method. 422 00:31:42,133 --> 00:31:45,068 It's called radio astronomy. 423 00:31:47,972 --> 00:31:51,772 This is the largest radio/radar telescope... 424 00:31:51,976 --> 00:31:56,037 ...on the planet Earth, the Arecibo Observatory. 425 00:31:58,850 --> 00:32:03,014 It's located in a remote valley on the island of Puerto Rico. 426 00:32:05,924 --> 00:32:09,724 It sends and receives radio signals. 427 00:32:10,028 --> 00:32:12,223 But it's so large and powerful... 428 00:32:12,430 --> 00:32:15,263 ...it can communicate with an identical radio telescope... 429 00:32:15,466 --> 00:32:18,560 ...15,000 light-years away... 430 00:32:18,770 --> 00:32:22,763 ...halfway to the center of the Milky Way galaxy. 431 00:32:25,777 --> 00:32:30,214 The Arecibo Observatory has been used, although sparingly... 432 00:32:30,415 --> 00:32:33,646 ...to search for signals from civilizations in space... 433 00:32:33,851 --> 00:32:35,842 ...and, just once... 434 00:32:36,054 --> 00:32:39,990 ...to broadcast a message to a distant star cluster... 435 00:32:40,191 --> 00:32:43,058 ...called "M13." 436 00:32:47,532 --> 00:32:50,194 But is there anyone out there to talk to? 437 00:32:53,738 --> 00:32:57,799 With 400 billion stars in the Milky Way galaxy alone... 438 00:32:58,009 --> 00:33:01,570 ...could ours be the only one with an inhabited planet? 439 00:33:04,315 --> 00:33:05,839 How much more likely it is... 440 00:33:06,050 --> 00:33:10,919 ...that the galaxy is throbbing and humming with advanced societies. 441 00:33:11,122 --> 00:33:14,649 Perhaps near one of those pinpoints of light in our night sky... 442 00:33:14,859 --> 00:33:17,191 ...someone quite different from us... 443 00:33:17,395 --> 00:33:20,728 ...is glancing idly at the star we call the sun... 444 00:33:20,932 --> 00:33:23,594 ...and entertaining, just for a moment... 445 00:33:23,801 --> 00:33:26,736 ...an outrageous speculation. 446 00:33:37,081 --> 00:33:40,642 There are an enormous number of stars. 447 00:33:42,253 --> 00:33:45,689 Only some of them will have planets suitable for life. 448 00:33:47,425 --> 00:33:51,259 On only some of those worlds will intelligence arise. 449 00:33:52,463 --> 00:33:55,660 And perhaps a few of those civilizations will avoid... 450 00:33:55,867 --> 00:34:00,600 ...the trap jointly set by their technology and their passions. 451 00:34:03,474 --> 00:34:08,002 If there are many civilizations, one of them should be rather close by. 452 00:34:09,213 --> 00:34:11,374 If there are few civilizations... 453 00:34:11,582 --> 00:34:15,279 ...then even the nearest may be very far away. 454 00:34:24,495 --> 00:34:29,194 This is one of the great questions: How many advanced civilizations... 455 00:34:29,400 --> 00:34:33,393 ...capable at least of radio astronomy are there in the Milky Way galaxy? 456 00:34:33,638 --> 00:34:38,575 Let's call the number of such civilizations by capital letter "N." 457 00:34:38,976 --> 00:34:41,501 It's a number. It depends on many things. 458 00:34:41,712 --> 00:34:44,272 It depends on the number of stars in the Milky Way. 459 00:34:44,482 --> 00:34:47,212 Let's call that N sub-star. 460 00:34:47,418 --> 00:34:49,716 The fraction of stars that have planets... 461 00:34:49,921 --> 00:34:52,321 ...is called f sub-p. 462 00:34:52,824 --> 00:34:56,055 The average number of planets in a given solar system... 463 00:34:56,260 --> 00:34:58,524 ...ecologically suitable for life... 464 00:34:59,097 --> 00:35:01,691 ...is called n sub-e. 465 00:35:01,899 --> 00:35:05,892 The fraction of suitable planets in which life actually arises... 466 00:35:06,104 --> 00:35:07,935 ...is called f sub-I. 467 00:35:08,139 --> 00:35:10,403 The fraction of inhabited planets... 468 00:35:10,608 --> 00:35:12,701 ...on which intelligence emerges... 469 00:35:12,910 --> 00:35:14,878 ...is called f sub-i. 470 00:35:15,847 --> 00:35:20,375 On the fraction of those planets in which the intelligent beings evolve... 471 00:35:20,585 --> 00:35:23,679 ...a technical, communicative civilization... 472 00:35:23,888 --> 00:35:25,287 ...call that f sub-c. 473 00:35:25,723 --> 00:35:30,092 Finally, it depends on the fraction of a planet's lifetime... 474 00:35:30,294 --> 00:35:33,889 ...that's graced by a technical civilization. 475 00:35:34,098 --> 00:35:35,656 Call that f sub-L. 476 00:35:38,269 --> 00:35:41,329 If we multiply all these numbers together... 477 00:35:41,539 --> 00:35:45,066 ...we've estimated N, the number of civilizations. 478 00:35:45,610 --> 00:35:48,704 This equation, due mainly to Frank Drake of Cornell... 479 00:35:48,913 --> 00:35:50,574 ...is only a sentence. 480 00:35:50,781 --> 00:35:53,409 The verb is "equals." 481 00:35:53,618 --> 00:35:57,952 So let's try to go through the program of this equation. 482 00:35:58,156 --> 00:36:00,750 By carefully counting the number of stars... 483 00:36:00,958 --> 00:36:03,825 ...in small but representative regions of the sky... 484 00:36:04,028 --> 00:36:07,725 ...we find that the total number of stars in the Milky Way... 485 00:36:07,932 --> 00:36:12,835 ...is about 400 billion. 486 00:36:13,037 --> 00:36:14,834 That's a lot of stars. 487 00:36:15,039 --> 00:36:16,370 What about planets? 488 00:36:16,574 --> 00:36:19,941 Well, in studies of double stars... 489 00:36:20,144 --> 00:36:24,444 ...and investigations of the motions of nearby stars... 490 00:36:24,649 --> 00:36:26,446 ...and in many theoretical studies... 491 00:36:26,651 --> 00:36:31,247 ...we get a strong hint that many... 492 00:36:31,455 --> 00:36:33,423 ...perhaps even most stars... 493 00:36:33,624 --> 00:36:35,216 ...are accompanied by planets. 494 00:36:35,426 --> 00:36:37,656 So let's take f sub-p... 495 00:36:37,862 --> 00:36:42,526 ...the fraction of stars that have planets as a quarter. 496 00:36:43,401 --> 00:36:46,598 Then, the total number of planetary systems in the galaxy... 497 00:36:46,804 --> 00:36:49,796 ...is 400 billion times a quarter... 498 00:36:50,007 --> 00:36:52,066 ...or 100 billion. 499 00:36:52,276 --> 00:36:56,269 We'll write down our running totals in red. 500 00:36:56,881 --> 00:36:59,008 Now if each system were to have, say... 501 00:36:59,217 --> 00:37:03,313 ...ten planets as ours does, there would be 100 billion times ten... 502 00:37:03,521 --> 00:37:05,819 ...or a trillion worlds in the galaxy. 503 00:37:06,023 --> 00:37:10,483 A vast arena for the cosmic drama. 504 00:37:10,928 --> 00:37:12,657 In our own solar system... 505 00:37:12,863 --> 00:37:16,230 ...there are several bodies that might be suitable for life... 506 00:37:16,434 --> 00:37:17,594 ...life of some sort. 507 00:37:17,802 --> 00:37:19,565 There's the Earth, of course... 508 00:37:19,770 --> 00:37:24,207 ...but there are possibilities for Mars, for Titan, perhaps for Jupiter. 509 00:37:24,408 --> 00:37:28,936 If other systems are similar, there may be many suitable worlds per system. 510 00:37:29,146 --> 00:37:31,478 But to be conservative, let's choose... 511 00:37:31,682 --> 00:37:34,048 ...n sub-e equal two. 512 00:37:34,252 --> 00:37:36,413 Two worlds suitable for life per system. 513 00:37:36,721 --> 00:37:38,985 The planets that are suitable for life... 514 00:37:39,190 --> 00:37:42,387 ...would be 100 billion times two, or 200 billion. 515 00:37:42,860 --> 00:37:44,327 Now what about life? 516 00:37:44,528 --> 00:37:46,553 Under very general cosmic conditions... 517 00:37:46,764 --> 00:37:51,633 ...the molecules of life are readily made and spontaneously self-assemble. 518 00:37:51,836 --> 00:37:55,272 It's conceivable there might be some impediment, like some... 519 00:37:55,473 --> 00:37:58,203 ...difficulty in the origin of the genetic code, say. 520 00:37:58,409 --> 00:38:02,038 Although that's very unlikely, given billions of years for evolution. 521 00:38:02,246 --> 00:38:06,580 On the Earth, life arose very fast after the planet was formed. 522 00:38:06,784 --> 00:38:09,309 So let's choose f sub-I... 523 00:38:09,520 --> 00:38:14,082 ...the fraction of suitable worlds in which life does arise, as a half. 524 00:38:14,458 --> 00:38:18,952 The number of planets in the Milky Way in which life has arisen once... 525 00:38:19,297 --> 00:38:22,425 ...is 100 billion times two, times a half. 526 00:38:22,633 --> 00:38:24,100 Or again, 100 billion. 527 00:38:26,871 --> 00:38:31,240 100 billion inhabited worlds. 528 00:38:31,909 --> 00:38:35,436 Now the estimates get tougher. 529 00:38:35,880 --> 00:38:38,906 Many individually unlikely events had to occur for... 530 00:38:39,116 --> 00:38:42,279 ...our species and our technology to emerge. 531 00:38:42,520 --> 00:38:45,512 On the other hand, there might be many different roads... 532 00:38:45,723 --> 00:38:47,486 ...to high technology. 533 00:38:47,692 --> 00:38:49,592 Some scientists think that... 534 00:38:49,794 --> 00:38:53,696 ...the path from trilobites to radio telescopes, or the equivalent... 535 00:38:53,898 --> 00:38:56,423 ...goes like a shot in all planetary systems. 536 00:38:56,634 --> 00:38:58,534 Other scientists disagree. 537 00:38:58,736 --> 00:39:02,331 Let's take some middle ground and choose f sub-i... 538 00:39:03,040 --> 00:39:04,507 ...as a tenth... 539 00:39:04,709 --> 00:39:08,304 ...and f sub-c as also a tenth. 540 00:39:08,512 --> 00:39:11,379 Meaning that only one percent, a tenth times a tenth... 541 00:39:11,582 --> 00:39:15,143 ...of inhabited planets eventually produce a technical civilization. 542 00:39:16,053 --> 00:39:19,545 If we were to multiply all these factors together... 543 00:39:19,757 --> 00:39:23,318 ...we would find 100 billion times a tenth times a tenth. 544 00:39:23,527 --> 00:39:27,588 Or one billion planets... 545 00:39:28,399 --> 00:39:32,859 ...on which civilizations have arisen at least once. 546 00:39:33,904 --> 00:39:37,863 Now what percentage of the lifetime of a planet... 547 00:39:38,075 --> 00:39:41,044 ...is marked by a technical civilization? 548 00:39:41,278 --> 00:39:44,611 Earth has harbored a civilization capable of radio astronomy... 549 00:39:44,815 --> 00:39:47,375 ...only for a few decades, the last few... 550 00:39:47,585 --> 00:39:50,418 ...out of a lifetime of a few billion years. 551 00:39:50,621 --> 00:39:53,181 It's hardly out of the question that we might... 552 00:39:53,391 --> 00:39:55,359 ...destroy ourselves tomorrow. 553 00:39:55,559 --> 00:39:59,996 If that's a typical case, then f sub-L... 554 00:40:00,197 --> 00:40:04,395 ...would be a few decades divided by a few billion years... 555 00:40:04,602 --> 00:40:08,538 ...or one hundred millionth... 556 00:40:08,739 --> 00:40:10,707 ...a very small number. 557 00:40:11,409 --> 00:40:14,503 And then, N would be a billion times a hundred millionth. 558 00:40:14,712 --> 00:40:19,649 Or N may be just... 559 00:40:19,884 --> 00:40:21,715 ...ten civilizations. 560 00:40:21,919 --> 00:40:24,979 A tiny smattering, a pitiful few... 561 00:40:25,189 --> 00:40:28,215 ...technological civilizations in the galaxy. 562 00:40:29,393 --> 00:40:31,554 But civilizations then... 563 00:40:31,762 --> 00:40:35,254 ...might take billions of years of tortuous evolution to arise... 564 00:40:35,466 --> 00:40:38,594 ...and then snuff themselves out in an instant of... 565 00:40:38,803 --> 00:40:40,737 ...unforgivable neglect. 566 00:40:40,938 --> 00:40:42,428 If this is a typical case... 567 00:40:42,640 --> 00:40:44,403 ...there may be few others... 568 00:40:44,608 --> 00:40:47,543 ...maybe nobody else at all for us to talk to. 569 00:40:51,882 --> 00:40:53,713 But consider the alternative: 570 00:40:53,918 --> 00:40:58,184 That occasionally civilizations learn to live with high technology... 571 00:40:58,389 --> 00:41:01,984 ...and survive for geological or stellar evolutionary time scales. 572 00:41:02,193 --> 00:41:05,356 If only one percent of civilizations can... 573 00:41:05,563 --> 00:41:08,555 ...survive technological adolescence... 574 00:41:08,966 --> 00:41:13,699 ...then f sub-L would be not 100 millionth... 575 00:41:13,904 --> 00:41:16,134 ...but only a hundredth. 576 00:41:16,340 --> 00:41:21,277 And then the number of civilizations would be a billion times a hundredth. 577 00:41:21,545 --> 00:41:24,810 The civilizations in the galaxy would be measured... 578 00:41:25,015 --> 00:41:27,245 ...in the millions. 579 00:41:28,786 --> 00:41:32,085 Millions of technical civilizations. 580 00:41:36,660 --> 00:41:40,528 So if civilizations do not always destroy themselves... 581 00:41:40,731 --> 00:41:43,598 ...shortly after discovering radio astronomy... 582 00:41:43,801 --> 00:41:47,066 ...then the sky may be softly humming... 583 00:41:47,271 --> 00:41:49,535 ...with messages from the stars... 584 00:41:49,740 --> 00:41:52,834 ...with signals from civilizations enormously older... 585 00:41:53,043 --> 00:41:55,341 ...and wiser than we. 586 00:41:57,815 --> 00:42:01,182 If there are millions of civilizations in the Milky Way... 587 00:42:01,385 --> 00:42:03,376 ...each capable of radio astronomy... 588 00:42:03,587 --> 00:42:06,715 ...how far away is the nearest one? 589 00:42:12,897 --> 00:42:16,025 If they're distributed randomly through space... 590 00:42:16,500 --> 00:42:20,266 ...then the nearest one will be some 200 light-years away. 591 00:42:20,671 --> 00:42:22,400 But within 200 light-years... 592 00:42:22,606 --> 00:42:25,769 ...there are hundreds of thousands of stars. 593 00:42:25,976 --> 00:42:28,444 To find the needle in this haystack... 594 00:42:28,646 --> 00:42:32,275 ...requires a dedicated and systematic search. 595 00:42:35,986 --> 00:42:40,116 Many cosmic radio sources have nothing to do with intelligent life. 596 00:42:40,324 --> 00:42:45,261 So how would we know that we were receiving a message? 597 00:42:48,933 --> 00:42:53,461 The transmitting civilization can make it very easy for us, if they wished. 598 00:42:53,671 --> 00:42:57,198 Imagine we're in the course of a systematic search. 599 00:42:57,408 --> 00:43:01,344 Or in the midst of some more conventional observations. 600 00:43:01,545 --> 00:43:03,445 And suppose one day... 601 00:43:03,647 --> 00:43:06,445 ...we find a strong signal slowly emerging. 602 00:43:06,650 --> 00:43:09,141 Not just some background hiss... 603 00:43:09,353 --> 00:43:13,915 ...but a methodical series of pulses. 604 00:43:14,124 --> 00:43:16,524 (SIGNAL PINGS) 605 00:43:17,728 --> 00:43:20,822 The numbers one, two, three, five... 606 00:43:21,031 --> 00:43:24,296 ...seven, eleven, thirteen. 607 00:43:24,501 --> 00:43:26,662 A signal made of prime numbers. 608 00:43:26,870 --> 00:43:30,966 Numbers divisible only by one and themselves. 609 00:43:34,178 --> 00:43:38,547 There is no natural astrophysical process that generates prime numbers. 610 00:43:38,749 --> 00:43:40,307 We would have to conclude... 611 00:43:40,517 --> 00:43:43,850 ...that someone fond of elementary mathematics... 612 00:43:44,054 --> 00:43:46,648 ...was saying hello. 613 00:43:47,091 --> 00:43:49,616 (SIGNAL PINGS) 614 00:43:52,529 --> 00:43:56,158 This would be no more than a beacon to attract our attention. 615 00:43:56,367 --> 00:43:58,767 The main message will be subtler... 616 00:43:58,969 --> 00:44:01,437 ...more hidden, far richer. 617 00:44:01,639 --> 00:44:04,301 We may have to work hard to find it. 618 00:44:08,646 --> 00:44:12,707 But the beacon signal alone would be profoundly significant. 619 00:44:12,916 --> 00:44:17,785 It would mean someone has learned to survive technological adolescence... 620 00:44:17,988 --> 00:44:20,980 ...that self-destruction is not inevitable... 621 00:44:21,191 --> 00:44:24,592 ...that we also may have a future. 622 00:44:29,433 --> 00:44:31,833 Such knowledge, it seems to me... 623 00:44:32,236 --> 00:44:35,069 ...might be worth a great price. 624 00:44:38,609 --> 00:44:39,576 Very likely... 625 00:44:39,777 --> 00:44:42,337 ...some new Champollion would go on... 626 00:44:42,546 --> 00:44:46,710 ...to decode the main message, using our interstellar Rosetta Stone: 627 00:44:46,917 --> 00:44:50,182 The common language of science and mathematics. 628 00:44:55,192 --> 00:44:58,423 Think of the glories of an exotic civilization... 629 00:44:58,629 --> 00:45:00,893 ...far more advanced than we... 630 00:45:01,098 --> 00:45:05,330 ...collected by the great radio telescopes of Earth. 631 00:45:05,536 --> 00:45:10,439 Perhaps they'd send a compilation of the knowledge of a million worlds: 632 00:45:10,641 --> 00:45:13,633 The Encyclopedia Galactica. 633 00:45:17,748 --> 00:45:19,773 Receiving an interstellar message... 634 00:45:19,983 --> 00:45:22,611 ...would be a major event in human history... 635 00:45:22,820 --> 00:45:27,757 ...and the beginning of the deprovincialization of our planet. 636 00:45:34,131 --> 00:45:36,827 A serious and systematic radio search... 637 00:45:37,034 --> 00:45:41,061 ...for extraterrestrial civilizations may come soon. 638 00:45:41,271 --> 00:45:44,434 Preliminary steps are being taken both in the United States... 639 00:45:44,641 --> 00:45:46,802 ...and in the Soviet Union. 640 00:45:48,545 --> 00:45:50,672 It's comparatively inexpensive. 641 00:45:50,881 --> 00:45:55,818 A search taking decades would cost less than the budget overruns... 642 00:45:56,019 --> 00:46:00,353 ...on a single modest weapons system in a single year. 643 00:46:03,060 --> 00:46:06,518 Our technology is now fully adequate... 644 00:46:06,730 --> 00:46:08,755 ...for this great challenge. 645 00:46:08,966 --> 00:46:11,127 But no systematic search program... 646 00:46:11,335 --> 00:46:15,203 ...has ever been approved by any nation on Earth. 647 00:46:18,242 --> 00:46:20,870 When will we decide to search for... 648 00:46:21,078 --> 00:46:25,811 ...what other civilizations there may be in the vast cosmic ocean? 649 00:46:31,522 --> 00:46:35,390 But whether there are only a few advanced galactic civilizations... 650 00:46:35,592 --> 00:46:36,889 ...or millions... 651 00:46:37,094 --> 00:46:41,292 ...shouldn't some of them have voyaged to Earth? 652 00:46:46,770 --> 00:46:51,139 On one hand, if even a small fraction of technical civilizations... 653 00:46:51,341 --> 00:46:55,072 ...learned to live with their potential for self-destruction... 654 00:46:55,279 --> 00:46:58,442 ...there should be enormous numbers of them in the galaxy. 655 00:46:59,016 --> 00:47:03,510 On the other hand, despite claims about UFOs and ancient astronauts... 656 00:47:03,720 --> 00:47:07,781 ...there's no creditable evidence that Earth has been visited, now or ever. 657 00:47:08,258 --> 00:47:10,488 But isn't this a contradiction? 658 00:47:10,694 --> 00:47:14,494 If the nearest civilization is, say, 200 light-years away... 659 00:47:14,698 --> 00:47:18,099 ...it'd take them only 200 years to get from there to here... 660 00:47:18,302 --> 00:47:19,530 ...at light speed. 661 00:47:19,736 --> 00:47:22,830 Even if they were traveling 1000 times slower than that... 662 00:47:23,040 --> 00:47:25,907 ...aliens could've come here during... 663 00:47:26,109 --> 00:47:28,339 ...the tenure of human beings on Earth. 664 00:47:28,545 --> 00:47:30,410 So why aren't they here? 665 00:47:31,281 --> 00:47:34,114 There's many possible answers. One is that... 666 00:47:34,318 --> 00:47:35,910 ...maybe we're the first. 667 00:47:36,119 --> 00:47:38,986 Some technical civilization has to be first... 668 00:47:39,189 --> 00:47:41,589 ...to emerge in the history of the galaxy. 669 00:47:41,792 --> 00:47:46,286 Or maybe all technical civilizations promptly destroy themselves. 670 00:47:46,496 --> 00:47:48,862 That seems to me very unlikely. 671 00:47:49,066 --> 00:47:51,261 Maybe there's some problem with space flight... 672 00:47:51,468 --> 00:47:53,993 ...that we've been too dumb to figure out. 673 00:47:54,204 --> 00:47:58,504 Or maybe they are here, but in hiding... 674 00:47:58,709 --> 00:48:01,303 ...because of an ethic of non-interference... 675 00:48:01,511 --> 00:48:03,376 ...with emerging civilizations. 676 00:48:03,580 --> 00:48:07,710 We might imagine them, curious and dispassionate... 677 00:48:07,918 --> 00:48:11,354 ...watching us to determine whether this year again... 678 00:48:11,555 --> 00:48:13,580 ...we manage to avoid self-destruction. 679 00:48:14,458 --> 00:48:19,361 But there's another explanation which is consistent with what we know. 680 00:48:19,596 --> 00:48:22,997 And that's that it's a big cosmos. 681 00:48:23,200 --> 00:48:27,796 If years ago, an advanced interstellar spacefaring civilization emerged... 682 00:48:28,005 --> 00:48:30,974 ...200 light-years away, why would they come here? 683 00:48:31,341 --> 00:48:34,139 They'd have no reason to think the Earth was special. 684 00:48:34,344 --> 00:48:39,008 There are no signs of technology, not even our radio transmissions... 685 00:48:39,216 --> 00:48:41,912 ...which have had time to go 200 light-years. 686 00:48:42,119 --> 00:48:45,350 From their point of view, all nearby planetary systems... 687 00:48:45,555 --> 00:48:48,991 ...might seem equally attractive for exploration. 688 00:48:52,496 --> 00:48:56,091 How would an interstellar civilization set out to explore... 689 00:48:56,300 --> 00:48:58,928 ...its neighboring star systems? 690 00:48:59,970 --> 00:49:02,234 It might establish staging posts... 691 00:49:02,439 --> 00:49:05,169 ...colonies, on planets of nearby stars. 692 00:49:05,375 --> 00:49:07,002 But this would take time. 693 00:49:07,210 --> 00:49:10,043 Time to find and modify favorable planets. 694 00:49:10,247 --> 00:49:12,408 Time to build new spacecraft. 695 00:49:13,617 --> 00:49:17,576 Eventually, later generations of explorers would set out... 696 00:49:17,788 --> 00:49:19,881 ...wending their way among the worlds... 697 00:49:20,090 --> 00:49:22,752 ...creating an interstellar nervous system... 698 00:49:22,960 --> 00:49:25,019 ...binding up the stars. 699 00:49:25,729 --> 00:49:28,789 Perhaps they'd come upon another expanding civilization... 700 00:49:28,999 --> 00:49:31,467 ...and encounter beings previously known... 701 00:49:31,668 --> 00:49:34,432 ...only from their radio transmissions. 702 00:49:34,638 --> 00:49:36,697 Star wars are unlikely. 703 00:49:36,907 --> 00:49:40,775 One civilization certainly would be far more advanced than the other. 704 00:49:40,978 --> 00:49:43,276 It would be no contest. 705 00:49:46,316 --> 00:49:48,011 Perhaps they would cooperate... 706 00:49:48,218 --> 00:49:52,985 ...exploring together a small province of the Milky Way. 707 00:49:57,561 --> 00:50:01,019 But even nearby civilizations could spend millions of years... 708 00:50:01,231 --> 00:50:03,290 ...roving between the stars... 709 00:50:03,500 --> 00:50:08,437 ...without ever stumbling upon our obscure solar system. 710 00:50:09,773 --> 00:50:13,607 In a galaxy of 400 billion suns... 711 00:50:13,810 --> 00:50:17,507 ...perhaps no one has found us just yet. 712 00:50:19,316 --> 00:50:23,446 Advanced interstellar civilizations would know about many worlds. 713 00:50:23,653 --> 00:50:26,315 Some inhabited, some barren. 714 00:50:26,523 --> 00:50:28,855 Perhaps they would share their findings... 715 00:50:29,059 --> 00:50:32,153 ...assembling some vast repository... 716 00:50:32,362 --> 00:50:35,331 ...of the knowledge of countless worlds. 717 00:50:35,532 --> 00:50:40,469 They might compile an Encyclopedia Galactica. 718 00:50:42,105 --> 00:50:46,166 Suppose we could browse through that encyclopedia. 719 00:50:52,082 --> 00:50:56,041 We would choose some nearby province of the galaxy... 720 00:50:56,253 --> 00:50:58,915 ...a region that's fairly well-explored. 721 00:50:59,122 --> 00:51:03,718 And then slowly leaf through the worlds. 722 00:51:24,614 --> 00:51:27,139 The young Champollion was inspired... 723 00:51:27,350 --> 00:51:30,842 ...by reading Fourier's description of Egypt. 724 00:51:31,054 --> 00:51:32,783 Imagine the impact on us... 725 00:51:32,989 --> 00:51:35,719 ...if we could study a rich compilation... 726 00:51:35,926 --> 00:51:38,224 ...of not merely one world... 727 00:51:38,428 --> 00:51:40,191 ...but billions. 728 00:52:16,933 --> 00:52:20,926 Just possibly, not too far from our solar system... 729 00:52:21,138 --> 00:52:23,698 ...we might find a technical civilization... 730 00:52:23,907 --> 00:52:26,808 ...only a little more advanced than we. 731 00:52:27,010 --> 00:52:31,174 Let's look them up in the Galactic Encyclopedia. 732 00:53:08,618 --> 00:53:12,281 What would a civilization far more advanced than ours... 733 00:53:12,489 --> 00:53:13,956 ...be up to? 734 00:53:17,594 --> 00:53:20,085 There may be engineering on a scale... 735 00:53:20,297 --> 00:53:23,266 ...that dwafts our proudest achievements. 736 00:53:23,466 --> 00:53:27,300 There may be cultures that disassemble other planets in their system... 737 00:53:27,504 --> 00:53:30,905 ...and reassemble them around their world to make a ring... 738 00:53:31,274 --> 00:53:34,835 ...or a shell with their planet inside. 739 00:53:47,157 --> 00:53:52,094 Imagine the energy crisis of a really advanced planetary civilization. 740 00:53:52,329 --> 00:53:54,160 They've used up all their fuels. 741 00:53:54,364 --> 00:53:56,491 They depend on solar power. 742 00:53:56,700 --> 00:54:00,329 But their growth is still severely limited by the energy available. 743 00:54:00,537 --> 00:54:03,870 An enormous amount of energy is generated by the local star. 744 00:54:04,074 --> 00:54:07,771 But most of the star's light doesn't fall on their planet. 745 00:54:07,978 --> 00:54:11,072 So perhaps they would build a shell... 746 00:54:11,281 --> 00:54:13,146 ...to surround their star... 747 00:54:13,350 --> 00:54:17,150 ...and harvest every photon of sunlight. 748 00:54:18,455 --> 00:54:21,390 Such beings, such civilizations... 749 00:54:21,591 --> 00:54:25,083 ...would bear little resemblance to anything we know. 750 00:54:51,421 --> 00:54:56,358 Perhaps someday there will be an entry in the Encyclopedia Galactica... 751 00:54:56,626 --> 00:54:58,355 ...for our planet. 752 00:54:58,561 --> 00:55:01,462 Or perhaps even now there exists somewhere... 753 00:55:01,665 --> 00:55:05,965 ...a planetary dossier, garnered from our television broadcasts... 754 00:55:06,169 --> 00:55:08,967 ...or from some discreet survey mission. 755 00:55:09,172 --> 00:55:13,609 They may summon up the index of blue worlds in our part of the Milky Way... 756 00:55:13,810 --> 00:55:16,574 ...until they came to the listing for Earth. 757 00:55:16,780 --> 00:55:19,340 What would they know about us? 758 00:55:24,721 --> 00:55:26,814 What would they think of us? 759 00:55:47,410 --> 00:55:50,937 We have always watched the stars and mused... 760 00:55:51,147 --> 00:55:55,675 ...about whether there are other beings who think and wonder. 761 00:55:58,388 --> 00:56:00,720 In a cosmic setting vast and old... 762 00:56:00,924 --> 00:56:05,554 ...beyond ordinary human understanding, we are a little lonely. 763 00:56:10,433 --> 00:56:14,893 In the deepest sense, the search for extraterrestrial intelligence... 764 00:56:15,105 --> 00:56:18,233 ...is a search for who we are. 765 00:56:26,683 --> 00:56:28,480 Since Cosmos was released... 766 00:56:28,685 --> 00:56:31,882 ...interest in UFOs has persisted. 767 00:56:32,088 --> 00:56:34,955 It seems to me that there are fewer sightings of... 768 00:56:35,158 --> 00:56:37,718 ...strange objects in the skies these days... 769 00:56:37,927 --> 00:56:42,660 ...and more stories of encounters with alleged extraterrestrials... 770 00:56:42,866 --> 00:56:46,962 ...like the account of Betty and Barney Hill that we dramatized. 771 00:56:47,170 --> 00:56:50,628 There are still people who claim to have been abducted by aliens... 772 00:56:50,840 --> 00:56:55,038 ...or even sexually abused, or even impregnated by them. 773 00:56:55,245 --> 00:57:00,182 Best-selling purportedly serious books have been written about such claims. 774 00:57:00,450 --> 00:57:03,942 But the critical fact remains that all we have still is... 775 00:57:04,154 --> 00:57:05,382 ...just anecdote. 776 00:57:05,588 --> 00:57:08,079 There are no close-up photos, no artifacts... 777 00:57:08,291 --> 00:57:10,282 ...nothing that'd convince a skeptic. 778 00:57:10,894 --> 00:57:13,124 All there are is stories. 779 00:57:13,329 --> 00:57:17,425 And stories just aren't good enough on a matter of this importance. 780 00:57:17,634 --> 00:57:20,159 I'm still waiting for hard evidence. 781 00:57:20,703 --> 00:57:25,367 The radio search for extraterrestrial intelligence has been picking up. 782 00:57:25,575 --> 00:57:29,443 In Harvard, Massachusetts, a radio telescope monitoring 8 million... 783 00:57:29,646 --> 00:57:31,341 ...separate radio channels... 784 00:57:31,548 --> 00:57:34,483 ...has been scanning the skies for signals. 785 00:57:34,684 --> 00:57:38,245 This program, called META, is supported entirely by... 786 00:57:38,455 --> 00:57:41,481 ...the Pasadena, California-based Planetary Society. 787 00:57:41,691 --> 00:57:44,285 Paid for by members' contributions. 788 00:57:44,494 --> 00:57:46,792 A similar planetary society search... 789 00:57:46,996 --> 00:57:51,160 ...to examine the southern skies and the center of the Milky Way... 790 00:57:51,367 --> 00:57:53,801 ...is to be performed in Argentina. 791 00:57:54,003 --> 00:57:56,972 These searches are by far... 792 00:57:57,173 --> 00:57:59,869 ...the most sophisticated ever attempted. 793 00:58:00,076 --> 00:58:02,408 A much more sensitive program... 794 00:58:02,612 --> 00:58:06,070 ...covering almost the entire accessible radio spectrum... 795 00:58:06,282 --> 00:58:08,273 ...is to be mustered by NASA. 796 00:58:09,486 --> 00:58:12,512 The search for extraterrestrial intelligence is central... 797 00:58:12,722 --> 00:58:16,385 ...to our understanding of the universe and our view of ourselves. 798 00:58:16,593 --> 00:58:18,288 It's well worth doing. 799 00:58:18,495 --> 00:58:20,588 But the simple fact is that... 800 00:58:20,797 --> 00:58:25,063 ...while we may consider extraterrestrial intelligence likely... 801 00:58:25,268 --> 00:58:28,760 ...there is as yet no evidence at all... 802 00:58:28,972 --> 00:58:30,371 ...that it exists. 803 00:58:30,707 --> 00:58:32,902 The search continues.