1 00:00:23,185 --> 00:00:25,250 "Stephen Hawking's Universe" is made possible 2 00:00:25,251 --> 00:00:28,017 by Alfred P. Sloan foundation to enhance public understanding 3 00:00:28,018 --> 00:00:30,184 of the role of science and technology, 4 00:00:30,185 --> 00:00:34,185 the Arthur Vining Davis foundations, 5 00:00:34,785 --> 00:00:37,983 the corporation for public broadcasting, 6 00:00:37,984 --> 00:00:40,184 and viewers like you. 7 00:00:40,185 --> 00:00:42,850 Corporate funding is provided by Amgen, 8 00:00:42,851 --> 00:00:44,883 unlocking the secrets of life through biotechnology. 9 00:00:44,884 --> 00:00:46,784 At Amgen, we produce medicines 10 00:00:46,785 --> 00:00:48,983 that improve people's lives today 11 00:00:48,984 --> 00:00:52,984 and bring hope for tomorrow. 12 00:00:59,018 --> 00:01:01,917 Stephen Hawking: In the last hundred years, 13 00:01:01,918 --> 00:01:03,950 our understanding of the universe 14 00:01:03,951 --> 00:01:07,951 has advanced far farther than in previous centuries. 15 00:01:08,751 --> 00:01:12,751 We have discovered that the universe and time itself 16 00:01:13,384 --> 00:01:17,384 had a beginning 15 billion years ago. 17 00:01:17,618 --> 00:01:20,883 There was a cosmic explosion of energy 18 00:01:20,884 --> 00:01:24,884 called the big bang. 19 00:01:25,218 --> 00:01:27,150 The energy produced 20 00:01:27,151 --> 00:01:29,417 all of the matter in the universe, 21 00:01:29,418 --> 00:01:32,383 from stars and galaxies to our own planet 22 00:01:32,384 --> 00:01:35,284 and even ourselves. 23 00:01:35,285 --> 00:01:38,517 Yet one question still needs an answer. 24 00:01:38,518 --> 00:01:41,217 How did the big bang begin? 25 00:01:41,218 --> 00:01:44,250 We need to know the laws 26 00:01:44,251 --> 00:01:47,083 that held at the moment of creation 27 00:01:47,084 --> 00:01:50,350 when the universe sprang into existence. 28 00:01:50,351 --> 00:01:53,983 Are these initial laws over and above the laws 29 00:01:53,984 --> 00:01:57,017 that tell us how the universe evolves? 30 00:01:57,018 --> 00:01:58,850 Or is there a theory of everything 31 00:01:58,851 --> 00:02:02,217 that governs the universe at all times 32 00:02:02,218 --> 00:02:06,218 and determines how it begins and develops? 33 00:02:09,818 --> 00:02:12,750 Narrator: "I shall never believe," said Einstein, 34 00:02:12,751 --> 00:02:14,950 "that god plays dice with the world," 35 00:02:14,951 --> 00:02:17,617 words that might bring gloom 36 00:02:17,618 --> 00:02:21,618 to the gambling capital of the east. 37 00:02:22,718 --> 00:02:24,717 Atlantic City has two sides -- 38 00:02:24,718 --> 00:02:27,684 one that's flush with big casinos, 39 00:02:27,685 --> 00:02:31,685 one old and simple as a small town. 40 00:02:37,851 --> 00:02:40,350 Today, physicists are grappling 41 00:02:40,351 --> 00:02:43,317 with a dual universe -- 42 00:02:43,318 --> 00:02:47,318 one great as all the cosmos, one infinitesimally small, 43 00:02:47,685 --> 00:02:51,184 both a puzzle to sydney Coleman. 44 00:02:51,185 --> 00:02:54,850 Coleman: physics starts out by trying to explain 45 00:02:54,851 --> 00:02:57,850 the sort of phenomena that occur in everyday life -- 46 00:02:57,851 --> 00:03:00,817 balls bouncing and planets round and round the sun, 47 00:03:00,818 --> 00:03:03,483 and all that stuff. 48 00:03:03,484 --> 00:03:05,717 And that's also pretty much the sort of stuff 49 00:03:05,718 --> 00:03:09,718 that you encounter in everyday life, 50 00:03:10,185 --> 00:03:12,217 and your tacit assumptions about those things 51 00:03:12,218 --> 00:03:14,917 and how they behave are deeply embedded 52 00:03:14,918 --> 00:03:17,283 in the language of everyday speech. 53 00:03:17,284 --> 00:03:21,284 That's how the language of everyday speech developed. 54 00:03:34,651 --> 00:03:38,117 Narrator: But physics has now gone beyond the familiar. 55 00:03:38,118 --> 00:03:40,450 Theorists like Coleman spend their days 56 00:03:40,451 --> 00:03:43,750 making imaginary journeys into strange new worlds, 57 00:03:43,751 --> 00:03:47,751 far removed from everyday life. 58 00:03:49,651 --> 00:03:51,350 as physics develops 59 00:03:51,351 --> 00:03:53,450 and physicists want to find out more and more, 60 00:03:53,451 --> 00:03:55,617 they try and understand physics 61 00:03:55,618 --> 00:03:58,884 which reveals itself only under extreme conditions -- 62 00:03:58,885 --> 00:04:02,885 on the inside of an atom, in a high-energy accelerator, 63 00:04:03,018 --> 00:04:07,018 in a quasar, during the beginning of the universe. 64 00:04:07,284 --> 00:04:10,584 Now it would be really remarkable if the concepts 65 00:04:10,585 --> 00:04:13,150 of everyday speech continued to be valid 66 00:04:13,151 --> 00:04:16,917 when we extend the universe of study so enormously. 67 00:04:16,918 --> 00:04:19,417 It's only natural that, 68 00:04:19,418 --> 00:04:22,117 as we get farther and farther from everyday experience, 69 00:04:22,118 --> 00:04:25,483 the theories we have to describe all this new stuff 70 00:04:25,484 --> 00:04:27,983 in addition to everyday experience, 71 00:04:27,984 --> 00:04:29,917 should look less and less intuitive. 72 00:04:29,918 --> 00:04:31,850 Why should your intuitions have developed 73 00:04:31,851 --> 00:04:33,717 to be good inside a quasar? 74 00:04:33,718 --> 00:04:36,817 Your ancestors did not spend any time inside quasars. 75 00:04:36,818 --> 00:04:39,884 So things seem to get, 76 00:04:39,885 --> 00:04:42,184 from our viewpoint, our earth-bound viewpoint, 77 00:04:42,185 --> 00:04:43,983 stranger and stranger. 78 00:04:43,984 --> 00:04:47,984 Narrator: That the universe is vast and expanding 79 00:04:48,518 --> 00:04:50,684 is accepted wisdom. 80 00:04:50,685 --> 00:04:52,117 That it began at a tiny point 81 00:04:52,118 --> 00:04:54,517 is accepted as well. 82 00:04:54,518 --> 00:04:57,750 Each extreme has its own theory to describe it. 83 00:04:57,751 --> 00:05:01,751 Coleman: When you trace the evolution of the universe 84 00:05:01,784 --> 00:05:04,983 backwards in time, you inevitably find yourself 85 00:05:04,984 --> 00:05:08,984 being pushed towards the physics of the very small. 86 00:05:13,651 --> 00:05:15,650 Narrator: The world of the minute 87 00:05:15,651 --> 00:05:17,950 has its own peculiar laws. 88 00:05:17,951 --> 00:05:21,050 And it was at this scale, 89 00:05:21,051 --> 00:05:24,217 millions of times smaller than a single atom, 90 00:05:24,218 --> 00:05:27,317 that the universe began. 91 00:05:27,318 --> 00:05:30,150 The study of the subatomic realm 92 00:05:30,151 --> 00:05:34,151 is called quantum mechanics. 93 00:05:50,804 --> 00:05:52,801 Woman: Two foundation stones, really, 94 00:05:52,802 --> 00:05:55,569 on which we've built current modern picture 95 00:05:55,570 --> 00:05:58,280 of the universe and the matter in it 96 00:05:58,281 --> 00:06:02,551 are quantum mechanics and general relativity. 97 00:06:04,980 --> 00:06:08,277 Einstein was instrumental in both of those theories. 98 00:06:08,278 --> 00:06:10,126 He was a founder of quantum theory 99 00:06:10,127 --> 00:06:14,396 and the sole inventor of general relativity. 100 00:06:14,023 --> 00:06:16,213 And the picture that they give us of the universe 101 00:06:16,214 --> 00:06:18,795 is a very good one in the sense, 102 00:06:18,796 --> 00:06:21,351 we can make a lot of predictions 103 00:06:21,352 --> 00:06:23,640 and explain a lot of phenomena. 104 00:06:23,641 --> 00:06:27,118 But the picture is really only partial in many ways. 105 00:06:27,119 --> 00:06:29,825 And one of the problems is that the two theories, 106 00:06:29,826 --> 00:06:33,525 in fact don't fit together 107 00:06:33,526 --> 00:06:35,495 Narrator: Einstein described 108 00:06:35,496 --> 00:06:37,031 the large-scale universe, 109 00:06:37,032 --> 00:06:38,701 a realm where gravity 110 00:06:38,702 --> 00:06:41,206 is the dominant force. 111 00:06:41,207 --> 00:06:42,474 Quantum mechanics concerns 112 00:06:42,475 --> 00:06:44,912 the behavior of atomic particles, 113 00:06:44,913 --> 00:06:48,152 governed by forces wholly different. 114 00:06:48,153 --> 00:06:51,891 But a complete theory of the universe 115 00:06:51,892 --> 00:06:54,396 has to embrace everything, 116 00:06:54,397 --> 00:06:58,397 from the tiniest traces to the largest galaxy. 117 00:06:58,404 --> 00:07:00,307 Dowker: Einstein believed 118 00:07:00,308 --> 00:07:03,246 that he could find a way to make them fit, 119 00:07:03,247 --> 00:07:05,549 because the methods that he had applied 120 00:07:05,550 --> 00:07:09,123 to problems in physics before had always worked. 121 00:07:09,124 --> 00:07:12,629 He'd been very successful in unifying things. 122 00:07:12,630 --> 00:07:14,332 He trusted his instincts. 123 00:07:14,333 --> 00:07:17,438 So his instinct was that there should be a theory 124 00:07:17,439 --> 00:07:21,439 which described the two theories together. 125 00:07:22,014 --> 00:07:24,017 Narrator: In his twilight years, 126 00:07:24,018 --> 00:07:27,256 Einstein pursued a quest he alone believed in. 127 00:07:27,257 --> 00:07:29,593 He went his own way, 128 00:07:29,594 --> 00:07:33,594 dreaming of a single theory of everything. 129 00:07:33,702 --> 00:07:35,939 Dowker: He spent decades on this work. 130 00:07:35,940 --> 00:07:37,875 He worked basically alone. 131 00:07:37,876 --> 00:07:40,848 I think that no one else shared his view 132 00:07:40,849 --> 00:07:44,849 that this was the way to go in unification. 133 00:07:44,856 --> 00:07:47,760 So he was very solitary, 134 00:07:47,761 --> 00:07:50,165 and he was working by himself 135 00:07:50,166 --> 00:07:54,005 up until the day he died. 136 00:07:54,006 --> 00:07:57,711 Narrator: Pages of his notes were found at his bedside, 137 00:07:57,712 --> 00:08:00,984 but his unifying theory was unfinished. 138 00:08:00,985 --> 00:08:04,985 He had failed to realize his dream. 139 00:08:11,705 --> 00:08:15,705 But Einstein, as always, was ahead of his time. 140 00:08:16,881 --> 00:08:19,651 Four decades later, 141 00:08:19,652 --> 00:08:22,957 his quest is being pursued by others. 142 00:08:22,958 --> 00:08:26,196 Theorists are rallying to find a single equation 143 00:08:26,197 --> 00:08:28,500 that can resolve the old contradiction 144 00:08:28,501 --> 00:08:32,501 between quantum mechanics and relativity. 145 00:08:32,809 --> 00:08:36,809 They, too, are looking for a theory of everything. 146 00:08:39,088 --> 00:08:42,928 Hawking: at the beginning, the universe is a single point. 147 00:08:42,929 --> 00:08:46,929 the next instant, it is enormous. 148 00:08:47,670 --> 00:08:51,670 To understand this properly, we need a theory of everything, 149 00:08:53,348 --> 00:08:57,348 which is still just beyond our grasp. 150 00:08:57,756 --> 00:09:00,626 However, we already 151 00:09:00,627 --> 00:09:03,431 have some ideas why the expansion 152 00:09:03,432 --> 00:09:07,432 of the early universe was precisely what it was. 153 00:09:14,853 --> 00:09:18,425 Narrator: In their effort to uncover the ultimate mystery, 154 00:09:18,426 --> 00:09:22,332 scientists have intuition and intellect to guide them. 155 00:09:22,333 --> 00:09:25,739 Yet slowly their search is being rewarded, 156 00:09:25,740 --> 00:09:28,477 one fledgling theory at a time, 157 00:09:28,478 --> 00:09:32,116 for they do have one more resource at their disposal. 158 00:09:32,117 --> 00:09:35,557 With new technology comes new insight. 159 00:09:35,558 --> 00:09:39,558 Observation offers inspiration. 160 00:09:41,936 --> 00:09:45,936 giant particle accelerators, such as SLAC, 161 00:09:46,044 --> 00:09:48,213 in Palo Alto, California, 162 00:09:48,214 --> 00:09:50,717 smash atoms into each other. 163 00:09:50,718 --> 00:09:53,456 These collisions create miniature explosions 164 00:09:53,457 --> 00:09:55,225 producing energies, temperatures, 165 00:09:55,226 --> 00:09:57,564 and pressures that mimic 166 00:09:57,565 --> 00:10:00,602 the very conditions of the big bang. 167 00:10:00,603 --> 00:10:03,608 In the 1970s, a striking portrait 168 00:10:03,609 --> 00:10:06,313 of the early universe emerged -- 169 00:10:06,314 --> 00:10:10,052 one poised on a cosmic knife edge. 170 00:10:10,053 --> 00:10:11,823 Man: What was always needed, 171 00:10:11,824 --> 00:10:13,859 and nobody had really pointed this out, 172 00:10:13,860 --> 00:10:15,663 was that you had to assume 173 00:10:15,664 --> 00:10:17,900 that the expansion rate of the early universe 174 00:10:17,901 --> 00:10:19,870 was tuned almost exactly right -- 175 00:10:19,871 --> 00:10:22,041 that is, almost exactly the right expansion rate 176 00:10:22,042 --> 00:10:24,211 so that the universe would be just on the verge 177 00:10:24,212 --> 00:10:27,050 of eternal expansion versus eventual collapse. 178 00:10:27,051 --> 00:10:29,922 If one talks about the universe 179 00:10:29,923 --> 00:10:32,694 at a time of about one second after the big bang, 180 00:10:32,695 --> 00:10:36,695 this tuning, this precise fixing of the expansion rate, 181 00:10:36,702 --> 00:10:40,408 had to be done to an accuracy of about 15 decimal places. 182 00:10:40,409 --> 00:10:42,612 If the universe just expanded 183 00:10:42,613 --> 00:10:44,482 one part in the 15th decimal place 184 00:10:44,483 --> 00:10:46,152 faster than we thought it had, 185 00:10:46,153 --> 00:10:47,521 it would fly apart 186 00:10:47,522 --> 00:10:49,792 without galaxies ever having a chance to form. 187 00:10:49,793 --> 00:10:52,096 If the universe at one second after the big bang 188 00:10:52,097 --> 00:10:54,033 were expanding with one number less 189 00:10:54,034 --> 00:10:56,504 in the 15th decimal place than what we thought, 190 00:10:56,505 --> 00:10:58,408 then the universe would collapse 191 00:10:58,409 --> 00:11:01,012 before galaxies had ever had a chance to form. 192 00:11:01,013 --> 00:11:02,548 To make the universe work, 193 00:11:02,549 --> 00:11:06,549 the universe had to be perched just on this borderline. 194 00:11:09,895 --> 00:11:13,502 Narrator: For 15 billion years, 195 00:11:13,503 --> 00:11:16,007 expansion has run its course in perfect measure. 196 00:11:16,008 --> 00:11:18,878 What fluke of physical law 197 00:11:18,879 --> 00:11:22,879 managed to strike this uncanny balance? 198 00:11:25,825 --> 00:11:29,825 Alan Guth was pondering equations of immense complexity. 199 00:11:30,132 --> 00:11:32,770 Yet the questions he was grappling with 200 00:11:32,771 --> 00:11:34,640 were so simple, 201 00:11:34,641 --> 00:11:38,641 they were the kind posed by a child. 202 00:11:46,864 --> 00:11:50,001 Man: When I was still a kid, 203 00:11:50,002 --> 00:11:51,872 i asked myself a question -- 204 00:11:51,873 --> 00:11:53,408 well, how could it happen 205 00:11:53,409 --> 00:11:55,579 that in different parts of the universe expansion 206 00:11:55,580 --> 00:11:58,083 started simultaneously? 207 00:11:58,084 --> 00:12:00,420 Who gave the signal? 208 00:12:00,421 --> 00:12:02,457 How can I understand it? 209 00:12:02,458 --> 00:12:04,728 And then I thought that maybe when I would grow older 210 00:12:04,729 --> 00:12:06,464 I will open the books 211 00:12:06,465 --> 00:12:08,268 which are written by clever professors, 212 00:12:08,269 --> 00:12:10,004 and I will find out the answer. 213 00:12:10,005 --> 00:12:12,943 When I grew older, 214 00:12:12,944 --> 00:12:16,650 I found that people did not know that the question exists. 215 00:12:16,651 --> 00:12:20,651 Narrator: A probing mind is a restless one. 216 00:12:21,627 --> 00:12:23,462 Andrei Linde, a russian, 217 00:12:23,463 --> 00:12:25,633 has unlocked a secret of creation. 218 00:12:25,634 --> 00:12:29,607 Linde: During the last 15 years, 219 00:12:29,608 --> 00:12:33,608 we've learned that the question can be answered. 220 00:12:33,682 --> 00:12:37,682 Narrator: Linde, like Guth, now lives in the United States. 221 00:12:38,658 --> 00:12:40,326 But in the '70s, 222 00:12:40,327 --> 00:12:42,263 they were on opposite sides of the world, 223 00:12:42,264 --> 00:12:44,634 unbeknownst to each other, simultaneously working 224 00:12:44,635 --> 00:12:47,439 on the same remarkable theory called "inflation." 225 00:12:47,440 --> 00:12:49,810 so, would you give me a glass of water? 226 00:12:49,811 --> 00:12:53,484 Sure. 227 00:12:53,485 --> 00:12:56,523 Narrator: Linde and Guth found a model 228 00:12:56,524 --> 00:13:00,397 for the early universe in the simplest of phenomena. 229 00:13:00,398 --> 00:13:02,901 If energy had somehow 230 00:13:02,902 --> 00:13:04,905 been trapped in a vacuum then released, 231 00:13:04,906 --> 00:13:07,710 space and time could have expanded, 232 00:13:07,711 --> 00:13:09,813 like so many bubbles. 233 00:13:09,814 --> 00:13:13,754 Perhaps these bubbles had collided, united, 234 00:13:13,755 --> 00:13:17,755 then rapidly expanded as one vast bubble, 235 00:13:18,063 --> 00:13:22,063 a symmetrical universe, growing smoothly, quickly, 236 00:13:22,805 --> 00:13:26,805 and evenly in all directions. 237 00:13:38,666 --> 00:13:42,666 Linde in Moscow and Guth in California 238 00:13:42,741 --> 00:13:45,345 were kindred spirits. 239 00:13:45,346 --> 00:13:48,884 Both needed to do detailed calculations 240 00:13:48,885 --> 00:13:52,885 to see if the idea could work. 241 00:13:56,733 --> 00:14:00,639 One winter's evening in 1979, 242 00:14:00,640 --> 00:14:04,514 Guth opened a notebook and began to write. 243 00:14:04,515 --> 00:14:08,515 Guth: I had not yet calculated everything through, that night, 244 00:14:10,224 --> 00:14:13,663 enough to convince myself that it was a fascinating idea 245 00:14:13,664 --> 00:14:14,598 and that it would probably work. 246 00:14:14,599 --> 00:14:17,303 The next morning 247 00:14:17,304 --> 00:14:19,740 I raced back to SLAC, and actually I kept track 248 00:14:19,741 --> 00:14:21,878 of my personal biking records to SLAC, 249 00:14:21,879 --> 00:14:23,948 and I set a new record that morning. 250 00:14:23,949 --> 00:14:25,852 Once I got there, I whipped out my notebook 251 00:14:25,853 --> 00:14:27,589 and started continuing the calculations, 252 00:14:27,590 --> 00:14:29,492 and by, I guess, the end of the morning, 253 00:14:29,493 --> 00:14:33,493 I convinced myself that it did fit together. 254 00:14:34,235 --> 00:14:37,239 Narrator: Linde was also making headway. 255 00:14:37,240 --> 00:14:41,240 But it wasn't long before his proverbial bubble burst. 256 00:14:41,448 --> 00:14:45,448 The numbers simply weren't adding up. 257 00:14:47,326 --> 00:14:50,196 Across the globe, at the same time, 258 00:14:50,197 --> 00:14:54,197 inflation was turning out to be deflating. 259 00:14:54,772 --> 00:14:57,276 Guth: As I continued to work on inflation, 260 00:14:57,277 --> 00:14:59,246 I did however discover that there was a serious problem 261 00:14:59,247 --> 00:15:03,247 in the way that inflation finally ended. 262 00:15:04,925 --> 00:15:07,594 It happened just like water boils. 263 00:15:07,595 --> 00:15:09,966 A bubble would form here, a bubble would form there, 264 00:15:09,967 --> 00:15:13,104 the bubbles would grow and collide 265 00:15:13,105 --> 00:15:15,676 and form an incredible morass of matter 266 00:15:15,677 --> 00:15:18,682 with tremendous non-uniformities in it. 267 00:15:18,683 --> 00:15:20,718 Would look, in fact, nothing whatever 268 00:15:20,719 --> 00:15:22,454 like our universe looks like. 269 00:15:22,455 --> 00:15:26,455 This was a serious problem that clearly required a modification. 270 00:15:31,038 --> 00:15:32,306 Thank you. 271 00:15:32,307 --> 00:15:33,676 You're welcome, sir. 272 00:15:33,677 --> 00:15:36,981 Narrator: Still, Guth went ahead and published his work. 273 00:15:36,982 --> 00:15:39,586 Despite its flaws, the theory 274 00:15:39,587 --> 00:15:43,587 caused a sensation. 275 00:15:43,661 --> 00:15:45,163 Guth: All of a sudden 276 00:15:45,164 --> 00:15:49,164 my career had just changed overnight dramatically, 277 00:15:49,338 --> 00:15:51,642 And it was an amazing experience that every scientist 278 00:15:51,643 --> 00:15:53,745 should have a chance to have once in his life. 279 00:15:53,746 --> 00:15:56,617 Narrator: In Russia, it's against scientific tradition 280 00:15:56,618 --> 00:15:59,121 to publish an idea without 281 00:15:59,122 --> 00:16:00,892 all the details worked out. 282 00:16:00,893 --> 00:16:03,396 Linde had labored long and hard, 283 00:16:03,397 --> 00:16:06,937 only to be outdone by his own principles. 284 00:16:06,938 --> 00:16:10,008 Worse, he feared his precious theory 285 00:16:10,009 --> 00:16:13,515 might be compromised by its premature unveiling. 286 00:16:13,516 --> 00:16:16,287 Today, at long last, 287 00:16:16,288 --> 00:16:20,288 comes a rare meeting of the minds. 288 00:16:20,561 --> 00:16:23,065 Linde: I don't know whether you know or not, 289 00:16:23,066 --> 00:16:24,869 but I had an ulcer 290 00:16:24,870 --> 00:16:26,538 which was induced by your work, 291 00:16:26,539 --> 00:16:28,542 in some sense, 292 00:16:28,543 --> 00:16:31,314 because when I heard about all these ideas, 293 00:16:31,315 --> 00:16:35,288 i was really, literally, thinking in these terms -- 294 00:16:35,289 --> 00:16:37,591 that god could not be so stupid 295 00:16:37,592 --> 00:16:40,030 to lose this opportunity 296 00:16:40,031 --> 00:16:42,868 to make the world in such a economical way. 297 00:16:42,869 --> 00:16:45,807 And when I found a solution, 298 00:16:45,808 --> 00:16:47,944 the ulcer is gone. 299 00:16:47,945 --> 00:16:51,945 Well, so sometimes physics helps. 300 00:16:55,058 --> 00:16:57,595 Narrator: Linde had a new idea. 301 00:16:57,596 --> 00:17:01,101 What if just one bubble of energy had inflated 302 00:17:01,102 --> 00:17:03,639 and become our universe? 303 00:17:03,640 --> 00:17:06,345 Linde: It was about 11:00 at night, 304 00:17:06,346 --> 00:17:08,782 and I could not keep myself from, well, 305 00:17:08,783 --> 00:17:10,418 this feeling of happiness. 306 00:17:10,419 --> 00:17:13,959 And I came to my wife and eventually waked her up, 307 00:17:13,960 --> 00:17:16,463 and I told her, "look, it seems that I know 308 00:17:16,464 --> 00:17:20,169 how the universe could have emerged." 309 00:17:20,170 --> 00:17:24,170 I first announced a new inflationary scenario 310 00:17:24,712 --> 00:17:27,149 in the meeting of quantum gravity in Moscow, 311 00:17:27,150 --> 00:17:29,753 which occurred in october '81. 312 00:17:29,754 --> 00:17:33,754 And at that time, many very good physicists in Moscow, 313 00:17:34,162 --> 00:17:38,162 and the star of the meeting was Steve Hawking. 314 00:17:39,339 --> 00:17:41,575 Hawking: I gave a seminar 315 00:17:41,576 --> 00:17:44,313 with Andrei translating. 316 00:17:44,314 --> 00:17:47,285 When I said there was a difficulty 317 00:17:47,286 --> 00:17:50,291 with Guth's idea of bubbles in collision, 318 00:17:50,292 --> 00:17:52,629 Andrei said that the whole universe 319 00:17:52,630 --> 00:17:55,134 could be a single bubble. 320 00:17:55,135 --> 00:17:56,636 I objected, 321 00:17:56,637 --> 00:17:58,941 because the bubble would have been bigger 322 00:17:58,942 --> 00:18:01,845 than the universe at the time. 323 00:18:01,846 --> 00:18:04,116 Linde: In the middle of his talk, 324 00:18:04,117 --> 00:18:06,554 he told that there was a very interesting idea 325 00:18:06,555 --> 00:18:08,925 of Andrei Linde recently. 326 00:18:08,926 --> 00:18:11,664 This was just my talk the previous day, 327 00:18:11,665 --> 00:18:13,700 and I was, oh, my heaven, he's translating it. 328 00:18:13,701 --> 00:18:15,537 And then he says 329 00:18:15,538 --> 00:18:18,342 but this model, this idea does not work, 330 00:18:18,343 --> 00:18:20,646 and let me explain why. 331 00:18:20,647 --> 00:18:22,817 And he starts talking and talking, 332 00:18:22,818 --> 00:18:24,687 and I'm translating it, 333 00:18:24,688 --> 00:18:26,491 and for a half an hour, 334 00:18:26,492 --> 00:18:28,894 in the face of all the institute, 335 00:18:28,895 --> 00:18:31,566 I was explaining to them why he knew inflation 336 00:18:31,567 --> 00:18:33,469 just simply cannot work. 337 00:18:33,470 --> 00:18:36,408 Narrator: Humiliation came in double doses to Andrei Linde. 338 00:18:36,409 --> 00:18:38,378 In front of respected colleagues, 339 00:18:38,379 --> 00:18:40,717 he saw his theory demolished. 340 00:18:40,718 --> 00:18:42,486 Linde: And then I told Steve, 341 00:18:42,487 --> 00:18:45,525 "Would you like to actually understand the details of this?" 342 00:18:45,526 --> 00:18:47,229 and he told me, "Sure." 343 00:18:47,230 --> 00:18:49,132 And then we disappeared for two hours. 344 00:18:49,133 --> 00:18:51,335 All the institute was trying to catch steve everywhere, 345 00:18:51,336 --> 00:18:53,373 and the famous physicist disappeared. 346 00:18:53,374 --> 00:18:55,477 The whole institute was in panic. 347 00:18:55,478 --> 00:18:59,478 Hawking: Linde and Guth had given us an important idea. 348 00:19:00,186 --> 00:19:02,923 Inflation accounts so neatly 349 00:19:02,924 --> 00:19:05,695 for the way the universe has to expand, 350 00:19:05,696 --> 00:19:09,101 I'm sure it must be part of the final picture. 351 00:19:09,102 --> 00:19:11,806 But inflation by itself 352 00:19:11,807 --> 00:19:15,280 does not explain the start of the universe. 353 00:19:15,281 --> 00:19:19,281 We still need a theory of everything for that. 354 00:19:19,321 --> 00:19:22,158 And applying the theory 355 00:19:22,159 --> 00:19:25,598 to the beginning of the universe would be difficult, 356 00:19:25,599 --> 00:19:27,936 because my own work had shown 357 00:19:27,937 --> 00:19:30,373 that the equations would break down 358 00:19:30,374 --> 00:19:32,644 at the big bang. 359 00:19:32,645 --> 00:19:34,314 Coleman: You can take 360 00:19:34,315 --> 00:19:37,220 Einstein's equations and run them backwards in time, 361 00:19:37,221 --> 00:19:38,822 not for a real universe, 362 00:19:38,823 --> 00:19:40,559 which is complicated, full of 363 00:19:40,560 --> 00:19:42,129 lumps and irregularities, 364 00:19:42,130 --> 00:19:44,132 but for a simplified model of the universe, 365 00:19:44,133 --> 00:19:46,402 where matter is distributed smoothly and uniformly 366 00:19:46,403 --> 00:19:49,308 throughout the universe. 367 00:19:49,309 --> 00:19:51,779 And when you did run it backwards in time, 368 00:19:51,780 --> 00:19:55,051 you found, eventually, there was a point in which 369 00:19:55,052 --> 00:19:57,723 everything came together at a single point, 370 00:19:57,724 --> 00:20:01,163 where gravitational fields became infinitely strong, 371 00:20:01,164 --> 00:20:04,169 energy densities became infinitely high. 372 00:20:04,170 --> 00:20:06,773 Technically we call it a singularity. 373 00:20:06,774 --> 00:20:10,774 Narrator: It is the netherworld of physical law. 374 00:20:11,048 --> 00:20:15,048 A singularity like the big bang is a realm beyond comprehension, 375 00:20:16,391 --> 00:20:20,391 where logic is replaced by chance... 376 00:20:23,972 --> 00:20:27,972 where matter is ruled by mere probability, 377 00:20:28,580 --> 00:20:31,451 and scientists must resort to summing up 378 00:20:31,452 --> 00:20:35,452 the rolls of the dice. 379 00:20:35,860 --> 00:20:38,698 Coleman: Physicists like to solve equations. 380 00:20:38,699 --> 00:20:40,701 They like to say, 381 00:20:40,702 --> 00:20:42,839 if this is the way things are now, 382 00:20:42,840 --> 00:20:45,009 this is the way they'll be a year from now. 383 00:20:45,010 --> 00:20:48,716 Once you hit a singularity, you can't do that. 384 00:20:48,717 --> 00:20:50,552 The equations blow up, 385 00:20:50,553 --> 00:20:52,289 and you don't know what to do with it. 386 00:20:52,290 --> 00:20:55,060 This is disturbing. 387 00:20:55,061 --> 00:20:58,066 People don't like singularities. 388 00:20:58,067 --> 00:20:59,803 Narrator: The best bet 389 00:20:59,804 --> 00:21:02,140 for solving the mysteries of singularities 390 00:21:02,141 --> 00:21:03,810 is quantum mechanics. 391 00:21:03,811 --> 00:21:07,250 Coleman: Quantum mechanics is probably the strangest thing 392 00:21:07,251 --> 00:21:11,251 human minds have ever thought up. 393 00:21:12,227 --> 00:21:16,133 I think if 1,000 philosophers were to work for a 1,000 years, 394 00:21:16,134 --> 00:21:19,339 trying to think up something of maximum strangeness, 395 00:21:19,340 --> 00:21:21,509 they wouldn't have thought up 396 00:21:21,510 --> 00:21:25,510 anything as strange as quantum mechanics. 397 00:21:26,018 --> 00:21:28,054 Narrator: Think of it as a game of chance. 398 00:21:28,055 --> 00:21:31,929 Quantum mechanics is based on Werner Heisenberg's 399 00:21:31,930 --> 00:21:33,464 "Uncertainty principle." 400 00:21:33,465 --> 00:21:35,301 A subatomic particle 401 00:21:35,302 --> 00:21:38,440 is too small to actually see directly. 402 00:21:38,441 --> 00:21:40,142 We can never know with precision 403 00:21:40,143 --> 00:21:43,616 where anything that small really is. 404 00:21:43,617 --> 00:21:45,051 But as it moves, 405 00:21:45,052 --> 00:21:47,656 it traces a path we can try to predict. 406 00:21:47,657 --> 00:21:51,657 We can venture a bet of its probable position. 407 00:21:54,236 --> 00:21:57,174 As it turns out, the uncertainties 408 00:21:57,175 --> 00:22:01,175 taken together add up to revelations altogether certain. 409 00:22:01,850 --> 00:22:04,922 Coleman: Strange as it is, it is apparently 410 00:22:04,923 --> 00:22:06,424 the way the universe works 411 00:22:06,425 --> 00:22:08,395 that enables us to make predictions 412 00:22:08,396 --> 00:22:10,933 about all sorts of processes involving atoms 413 00:22:10,934 --> 00:22:13,838 or elementary particles colliding, 414 00:22:13,839 --> 00:22:17,839 That are verified by experiment to amazing degrees of accuracy. 415 00:22:21,085 --> 00:22:25,058 Narrator: The problem is the laws of uncertainty 416 00:22:25,059 --> 00:22:26,962 only make sense for the universe 417 00:22:26,963 --> 00:22:30,435 as a whole at its moment of creation. 418 00:22:30,436 --> 00:22:33,640 They can't be applied to the universe today, 419 00:22:33,641 --> 00:22:36,379 to the stars and planets governed by gravity, 420 00:22:36,380 --> 00:22:40,380 and with motions described by relativity. 421 00:22:42,191 --> 00:22:44,694 Coleman: A lot of people have been trying to combine 422 00:22:44,695 --> 00:22:47,332 quantum mechanics with gravity over the years, 423 00:22:47,333 --> 00:22:50,270 a quantum mechanical replacement 424 00:22:50,271 --> 00:22:54,271 for Einstein's general relativity. 425 00:22:54,346 --> 00:22:58,346 Hawking: I wanted to resolve the problem of the singularity. 426 00:22:58,988 --> 00:23:01,891 After all, I was largely responsible 427 00:23:01,892 --> 00:23:04,330 for raising it in the first place. 428 00:23:04,331 --> 00:23:08,331 Maybe one could choose a path around it. 429 00:23:08,905 --> 00:23:11,208 Coleman: Hawking saw that the uncertainty 430 00:23:11,209 --> 00:23:13,146 that came when you tried 431 00:23:13,147 --> 00:23:15,617 to combine quantum mechanics and gravity 432 00:23:15,618 --> 00:23:17,621 was in fact an escape route, 433 00:23:17,622 --> 00:23:20,359 and could be used to get away from this -- 434 00:23:20,360 --> 00:23:22,530 avoid the singularity problem, 435 00:23:22,531 --> 00:23:25,368 which he himself had done so much to raise. 436 00:23:25,369 --> 00:23:27,238 In a remarkable paper 437 00:23:27,239 --> 00:23:29,543 done in collaboration with James Hartle, 438 00:23:29,544 --> 00:23:32,948 Hawking was able to solve 439 00:23:32,949 --> 00:23:36,656 a very, very simplified model of the universe. 440 00:23:36,657 --> 00:23:39,527 Hawking: Jim Hartle and I showed 441 00:23:39,528 --> 00:23:41,397 how a universe like our own 442 00:23:41,398 --> 00:23:45,398 could be born without the troublesome singularity. 443 00:23:45,439 --> 00:23:49,439 It involved the use of what is called imaginary time. 444 00:23:50,047 --> 00:23:54,047 This may sound like science fiction, 445 00:23:55,156 --> 00:23:58,496 but it is a well-defined scientific concept 446 00:23:58,497 --> 00:24:01,935 that science fiction borrowed. 447 00:24:01,936 --> 00:24:05,936 The idea was that in imaginary time 448 00:24:06,511 --> 00:24:08,880 the universe has no boundary, 449 00:24:08,881 --> 00:24:12,654 no beginning or end. 450 00:24:12,655 --> 00:24:16,655 It just curls round on itself like the surface of the earth. 451 00:24:19,000 --> 00:24:22,405 Coleman: It was a complete quantum mechanical description 452 00:24:22,406 --> 00:24:25,979 of everything that could be said 453 00:24:25,980 --> 00:24:29,980 about this simplified model of the universe, 454 00:24:30,821 --> 00:24:34,821 and it had no singularities. 455 00:24:36,198 --> 00:24:38,267 It's possible that quantum mechanics 456 00:24:38,268 --> 00:24:40,438 is the answer to the problem of the singularity. 457 00:24:40,439 --> 00:24:44,312 Hawking: I have to make it clear 458 00:24:44,313 --> 00:24:48,313 that the no-boundary universe is just a proposal, 459 00:24:48,420 --> 00:24:52,420 but it has some interesting implications. 460 00:24:52,461 --> 00:24:54,864 Without boundaries, 461 00:24:54,865 --> 00:24:58,605 the universe has no beginning and no end. 462 00:24:58,606 --> 00:25:02,511 We don't have to explain its creation. 463 00:25:02,512 --> 00:25:05,217 The universe simply exists. 464 00:25:05,218 --> 00:25:09,218 But the consequences of the no-boundary proposal 465 00:25:09,258 --> 00:25:12,096 cannot be worked out fully 466 00:25:12,097 --> 00:25:15,669 without a complete quantum theory of gravity 467 00:25:15,670 --> 00:25:18,340 that will unite general relativity 468 00:25:18,341 --> 00:25:21,079 and quantum mechanics. 469 00:25:21,080 --> 00:25:25,080 We are back to the search for a theory of everything. 470 00:25:31,231 --> 00:25:35,231 Narrator: While others turn to the heavens for their models, 471 00:25:36,508 --> 00:25:40,347 cosmologist Lee Smolin looks a little closer to home. 472 00:25:40,348 --> 00:25:43,520 The answer to his universe is not contained 473 00:25:43,521 --> 00:25:47,521 in any mathematical equation. 474 00:25:48,897 --> 00:25:52,897 Smolin: The hope was that there would be one simple law 475 00:25:53,306 --> 00:25:55,842 which would have a unique solution, 476 00:25:55,843 --> 00:25:57,578 which would explain 477 00:25:57,579 --> 00:25:59,716 how the universe is, 478 00:25:59,717 --> 00:26:01,953 the history of the universe, and so forth. 479 00:26:01,954 --> 00:26:05,894 And that hope that all the questions 480 00:26:05,895 --> 00:26:08,899 would be answered in a single law 481 00:26:08,900 --> 00:26:12,900 is what has not happened. 482 00:26:14,009 --> 00:26:17,114 So I wondered about this a great deal. 483 00:26:17,115 --> 00:26:19,886 And I was thinking about this 484 00:26:19,887 --> 00:26:22,290 at the same time that I was reading about biology. 485 00:26:22,291 --> 00:26:25,930 That led me to begin to wonder 486 00:26:25,931 --> 00:26:28,435 whether the answers to some of the questions 487 00:26:28,436 --> 00:26:31,207 in elementary particle physics 488 00:26:31,208 --> 00:26:34,345 did not rest in a single unique theory, 489 00:26:34,346 --> 00:26:38,346 but maybe would be a result of historical accident, 490 00:26:39,222 --> 00:26:42,127 and maybe there could be a process by which, 491 00:26:42,128 --> 00:26:44,298 through a series of developments 492 00:26:44,299 --> 00:26:46,535 in the early history of the universe, 493 00:26:46,536 --> 00:26:50,041 somehow the universe chose what its parameters were. 494 00:26:50,042 --> 00:26:54,042 The wonderful thing about the biological world 495 00:26:54,311 --> 00:26:54,764 is that it's so complicated. 496 00:26:54,765 --> 00:26:57,400 There are so many different species, 497 00:26:57,401 --> 00:27:01,239 they're so beautiful in so many different ways, 498 00:27:01,240 --> 00:27:05,246 and one would think that one could not possibly explain this, 499 00:27:05,379 --> 00:27:08,416 which is of course what people thought before Darwin. 500 00:27:08,417 --> 00:27:10,986 What Darwin discovered 501 00:27:10,987 --> 00:27:14,891 is that there is a rational way to understand 502 00:27:14,892 --> 00:27:17,428 how such enormous variety and complexity 503 00:27:17,429 --> 00:27:19,797 can come to be in the natural world, 504 00:27:19,798 --> 00:27:21,900 without being put there in the first place. 505 00:27:21,901 --> 00:27:25,907 And the basic idea is that you have some population 506 00:27:26,541 --> 00:27:29,110 which can reproduce itself, 507 00:27:29,111 --> 00:27:31,213 that when it does so, 508 00:27:31,214 --> 00:27:35,185 there are small, random changes in the characteristics, 509 00:27:35,186 --> 00:27:39,192 and that these characteristics lead to differences 510 00:27:40,326 --> 00:27:43,329 in how well the creatures survive. 511 00:27:43,330 --> 00:27:46,066 Narrator: Smolin's theory of everything 512 00:27:46,067 --> 00:27:48,737 has a familiar ring. 513 00:27:48,738 --> 00:27:51,808 it's inspired by darwin's idea of natural selection. 514 00:27:51,809 --> 00:27:55,814 Smolin: The universe, like the biological world, 515 00:27:56,682 --> 00:27:59,418 seems to have discovered all sorts of ways 516 00:27:59,419 --> 00:28:03,023 to keep itself out of equilibrium and to keep 517 00:28:03,024 --> 00:28:05,159 an enormous variety of things going on. 518 00:28:05,160 --> 00:28:07,629 And the universe also invents life, 519 00:28:07,630 --> 00:28:09,798 which is very impressive, 520 00:28:09,799 --> 00:28:12,336 and many cosmologists have wondered, 521 00:28:12,337 --> 00:28:14,105 how could it be that all of this 522 00:28:14,106 --> 00:28:16,374 improbable structure and organization comes to be, 523 00:28:16,375 --> 00:28:19,045 out of the world that evolves out of the big bang. 524 00:28:19,046 --> 00:28:23,051 Narrator: Imagine the universe as a product 525 00:28:23,485 --> 00:28:26,755 of the same evolutionary processes 526 00:28:26,756 --> 00:28:30,761 that later gave rise to us. 527 00:28:34,032 --> 00:28:36,034 Smolin: If one studies astronomy 528 00:28:36,035 --> 00:28:39,038 on scales much, much larger than the Earth -- 529 00:28:39,039 --> 00:28:42,076 for example, the disc of a spiral galaxy -- 530 00:28:42,077 --> 00:28:45,013 one discovers it's a complex, self-organized system, 531 00:28:45,014 --> 00:28:49,019 somewhat akin to biology on a much simpler level. 532 00:28:53,125 --> 00:28:55,059 It turns out that 533 00:28:55,060 --> 00:28:59,066 the ideas by which we understand the patterns on sea shells 534 00:28:59,633 --> 00:29:02,369 or the stripes on an animal's coat 535 00:29:02,370 --> 00:29:04,739 are very close to the ideas by which we understand 536 00:29:04,740 --> 00:29:06,909 how the galaxies get 537 00:29:06,910 --> 00:29:10,414 their beautiful spiral structures. 538 00:29:10,415 --> 00:29:14,420 What occurred to me was maybe the explanation 539 00:29:14,453 --> 00:29:18,292 for why the parameters of the laws of physics 540 00:29:18,293 --> 00:29:20,761 are right to produce all this complexity 541 00:29:20,762 --> 00:29:23,164 is like the explanation of biology. 542 00:29:23,165 --> 00:29:27,171 The new possibility which Darwin gave us 543 00:29:27,404 --> 00:29:29,807 is that a system can have all the beauty 544 00:29:29,808 --> 00:29:33,278 and variety and complexity of our world 545 00:29:33,279 --> 00:29:34,880 and be assembled from itself, 546 00:29:34,881 --> 00:29:36,950 that it can organize itself over time. 547 00:29:36,951 --> 00:29:40,822 What 20th-century science 548 00:29:40,823 --> 00:29:44,829 is leading to is, in my view -- 549 00:29:44,995 --> 00:29:46,529 and of course, could be wrong -- 550 00:29:46,530 --> 00:29:50,101 the culmination of this view of the universe 551 00:29:50,102 --> 00:29:53,806 as something which does create itself and assemble itself. 552 00:29:53,807 --> 00:29:57,812 Of course, it's a new idea, 553 00:29:57,879 --> 00:30:01,483 and it's very, very far from being demonstrated, 554 00:30:01,484 --> 00:30:04,687 although I must say that I'm very struck by the fact 555 00:30:04,688 --> 00:30:06,690 that it wasn't proved wrong yet. 556 00:30:06,691 --> 00:30:10,328 But the idea that maybe the universe as a whole 557 00:30:10,329 --> 00:30:13,366 organized itself by some natural process 558 00:30:13,367 --> 00:30:16,771 makes one feel more at home. 559 00:30:16,772 --> 00:30:20,475 Narrator: What preceded creation? 560 00:30:20,476 --> 00:30:23,546 The theorists who are exploring the question 561 00:30:23,547 --> 00:30:25,783 are pioneers, standing alone at the frontiers 562 00:30:25,784 --> 00:30:28,352 of an impenetrable wilderness. 563 00:30:28,353 --> 00:30:32,359 For Andrei Linde, this lonely pursuit 564 00:30:33,260 --> 00:30:36,731 was taking its toll. 565 00:30:36,732 --> 00:30:39,500 '85 was the first year of perestroika, 566 00:30:39,501 --> 00:30:41,470 so the first year of perestroika, 567 00:30:41,471 --> 00:30:43,506 Gorbachev just came to power, 568 00:30:43,507 --> 00:30:46,710 and they started reconstructing everything, 569 00:30:46,711 --> 00:30:48,414 which is a translation of the word perestroika, 570 00:30:48,415 --> 00:30:50,082 the reconstruction. 571 00:30:50,083 --> 00:30:53,153 And as a first step, 572 00:30:53,154 --> 00:30:57,159 they'd completely forbidden us to send our papers abroad, 573 00:30:57,793 --> 00:31:01,799 so I had a feeling that I am living with my mouth shut. 574 00:31:01,799 --> 00:31:05,235 I cannot tell others what I am doing, 575 00:31:05,236 --> 00:31:08,374 and this was pretty depressing. 576 00:31:08,375 --> 00:31:11,310 So I became so much depressed 577 00:31:11,311 --> 00:31:13,480 that I actually became simply ill, 578 00:31:13,481 --> 00:31:15,550 and now I was lying in the bed 579 00:31:15,551 --> 00:31:18,755 for about a month and a half, and then, all of a sudden, 580 00:31:18,756 --> 00:31:21,725 there was a call from academy of sciences. 581 00:31:21,726 --> 00:31:24,195 They told me that I must go to italy 582 00:31:24,196 --> 00:31:26,131 to give some popular lectures on astronomy. 583 00:31:26,132 --> 00:31:29,069 And I told them, "I am ill, I cannot go." 584 00:31:29,070 --> 00:31:32,907 Narrator: He'd suffered years of frustration 585 00:31:32,908 --> 00:31:34,476 and months of repression. 586 00:31:34,477 --> 00:31:38,482 Now Linde was suddenly free to say what he liked. 587 00:31:38,515 --> 00:31:41,919 He had 24 hours to find something worth saying. 588 00:31:41,920 --> 00:31:45,925 Linde: After this year with the mouth shut, 589 00:31:47,260 --> 00:31:50,897 they are suggesting to me that if I do something, 590 00:31:50,898 --> 00:31:53,802 then tomorrow it will be sent there 591 00:31:53,803 --> 00:31:56,171 by diplomatic mail without any approvement, 592 00:31:56,172 --> 00:31:58,074 without any signatures, 593 00:31:58,075 --> 00:32:00,344 without any of this bureaucratic work. 594 00:32:00,345 --> 00:32:02,647 Tomorrow it will be in Italy. 595 00:32:02,648 --> 00:32:06,319 On the other hand, it must be done just immediately, 596 00:32:06,320 --> 00:32:09,089 and I am really sick. 597 00:32:09,090 --> 00:32:11,091 I just cannot. 598 00:32:11,092 --> 00:32:13,862 I took my head like that, and I started thinking, 599 00:32:13,863 --> 00:32:16,766 "What can I invent within half an hour or so? 600 00:32:16,767 --> 00:32:18,969 "I will write it today in the evening, 601 00:32:18,970 --> 00:32:20,972 "and tomorrow I'll send it to Italy. 602 00:32:20,973 --> 00:32:23,275 What can I do within half an hour?" 603 00:32:23,276 --> 00:32:25,278 And within half an hour, 604 00:32:25,279 --> 00:32:29,284 I have got a theory of self-reproducing universe. 605 00:32:29,818 --> 00:32:32,387 Narrator: In Linde's new theory, 606 00:32:32,388 --> 00:32:36,394 inflation must have produced a multitude of universes. 607 00:32:36,827 --> 00:32:40,833 Instead of just one growing, there had to be many -- 608 00:32:41,400 --> 00:32:43,468 each universe different, 609 00:32:43,469 --> 00:32:46,773 each the product of its own big bang. 610 00:32:46,774 --> 00:32:50,779 In time, they will seed other universes 611 00:32:51,514 --> 00:32:54,885 so the process goes on forever. 612 00:32:54,886 --> 00:32:58,891 Linde had experienced his own conceptual big bang. 613 00:33:02,095 --> 00:33:06,101 Out of depression had come pure inspiration. 614 00:33:06,300 --> 00:33:10,305 Linde: When I was really going to Italy, 615 00:33:10,873 --> 00:33:13,443 I had four papers written 616 00:33:13,444 --> 00:33:15,946 on the theory of self-reproducing universe. 617 00:33:15,947 --> 00:33:19,918 I smuggled them to Italy without any permission, 618 00:33:19,919 --> 00:33:23,823 and I came to Rome, and I gave lectures in Rome. 619 00:33:23,824 --> 00:33:26,728 I came to Torino, I gave lectures in Torino. 620 00:33:26,729 --> 00:33:30,734 I came to Trieste, and I gave the lectures, 621 00:33:31,635 --> 00:33:35,505 and then they delivered my body to the railway station 622 00:33:35,506 --> 00:33:39,512 and put me into a luxurious sleeping wagon, 623 00:33:41,281 --> 00:33:43,717 and I looked into myself in the mirror -- 624 00:33:43,718 --> 00:33:47,723 this was '86, where I was 38 years old. 625 00:33:47,957 --> 00:33:49,892 I looked in the mirror 626 00:33:49,893 --> 00:33:52,528 and I have seen the body of an old person, 627 00:33:52,529 --> 00:33:56,535 slowly moving from Trieste into the direction of Rome. 628 00:33:56,602 --> 00:34:00,607 and then, after a while, I became healthy again. 629 00:34:02,276 --> 00:34:06,281 And since that time I did not have such a depression, 630 00:34:07,082 --> 00:34:11,088 which in a certain sense may be unfortunate. 631 00:34:15,995 --> 00:34:19,465 Hawking: Smolin and Linde's evolutionary theories 632 00:34:19,466 --> 00:34:22,769 have failed to catch on. 633 00:34:22,770 --> 00:34:25,340 Most cosmologists, like me, 634 00:34:25,341 --> 00:34:28,110 still want to find a single explanation 635 00:34:28,111 --> 00:34:32,116 of a single universe. 636 00:34:38,526 --> 00:34:42,531 Narrator: In 1985, a promising new theory emerged, 637 00:34:42,797 --> 00:34:46,803 raising hopes the search would soon be over. 638 00:34:47,538 --> 00:34:51,075 You're tuned to WBAI, 99.5 fm on your dial. 639 00:34:51,076 --> 00:34:55,081 Coming up next, "Explorations" with dr. Michio Kaku. 640 00:34:56,149 --> 00:34:58,251 Welcome. This is "Exploration" 641 00:34:58,252 --> 00:35:00,153 This is dr. Michio Kaku, 642 00:35:00,154 --> 00:35:01,822 professor of theoretical physics, 643 00:35:01,823 --> 00:35:04,359 and this is a program devoted to science 644 00:35:04,360 --> 00:35:07,029 and the fantastic discoveries as we explore the universe, 645 00:35:07,030 --> 00:35:10,033 and of course, super string theory, 646 00:35:10,034 --> 00:35:12,604 the theory that will perhaps 647 00:35:12,605 --> 00:35:15,741 give us an explanation for the entire universe. 648 00:35:15,742 --> 00:35:19,413 Some people say the instant of the big bang, 649 00:35:19,414 --> 00:35:23,419 the universe was a dot. 650 00:35:28,059 --> 00:35:30,929 The new picture is that it's like a bowl of noodles, 651 00:35:30,930 --> 00:35:32,864 a bowl of noodles where we have 652 00:35:32,865 --> 00:35:34,867 thousands and millions of little strings, 653 00:35:34,868 --> 00:35:36,436 vibrating at the instant of time, 654 00:35:36,437 --> 00:35:39,540 that exploded, creating 655 00:35:39,541 --> 00:35:42,945 the enormous diversity of matter and energy 656 00:35:42,946 --> 00:35:45,114 that we see around us. 657 00:35:45,115 --> 00:35:48,618 Super string theory is so bizarre, so strange, 658 00:35:48,619 --> 00:35:51,890 that we were not destined to see this theory 659 00:35:51,891 --> 00:35:53,359 in the 20th century. 660 00:35:53,360 --> 00:35:57,365 Many of us believe that it's really 21st-century physics 661 00:35:58,500 --> 00:36:00,368 that fell accidentally 662 00:36:00,369 --> 00:36:02,805 into the 20th century. 663 00:36:02,806 --> 00:36:06,811 Narrator: Bubbles have their proponents, 664 00:36:08,280 --> 00:36:11,483 uncertainty has its adherents, 665 00:36:11,484 --> 00:36:15,188 but strings are the stuff of zealots. 666 00:36:15,189 --> 00:36:18,893 It's based on a rarefied branch of mathematics, 667 00:36:18,894 --> 00:36:21,797 and it's an idea so ahead of its time 668 00:36:21,798 --> 00:36:25,268 that its time may not yet have come. 669 00:36:25,269 --> 00:36:27,705 Kaku: Einstein spent the last 30 years of his life 670 00:36:27,706 --> 00:36:29,875 trying to create a theory of everything, 671 00:36:29,876 --> 00:36:32,512 a theory of black holes, of galaxies, 672 00:36:32,513 --> 00:36:35,883 and a theory of atoms, of light, of force. 673 00:36:35,884 --> 00:36:38,653 So we have two great theories of physics -- 674 00:36:38,654 --> 00:36:41,491 the theory of the very big, Einstein's theory of relativity, 675 00:36:41,492 --> 00:36:44,060 and the theory of the very small, 676 00:36:44,061 --> 00:36:45,295 the quantum theory. 677 00:36:45,296 --> 00:36:46,030 And these two theories 678 00:36:46,031 --> 00:36:49,101 they are incompatible. 679 00:36:49,102 --> 00:36:50,904 One is smooth, beautiful, like marble, 680 00:36:50,905 --> 00:36:54,241 and the other one is coarse and grainy like wood. 681 00:36:54,242 --> 00:36:57,913 And to get them to meet together has been the object 682 00:36:57,914 --> 00:37:01,851 of the last 50 years of intense investigation. 683 00:37:01,852 --> 00:37:04,889 Today, we think we have it. 684 00:37:04,890 --> 00:37:07,626 We think we have the super string theory, 685 00:37:07,627 --> 00:37:09,962 which is perhaps the most fantastic, 686 00:37:09,963 --> 00:37:11,698 the most marvelous theory ever proposed 687 00:37:11,699 --> 00:37:15,704 in the history of science. 688 00:37:20,844 --> 00:37:24,149 Narrator: String theory borders on mysticism. 689 00:37:24,150 --> 00:37:27,086 It contemplates a universe 690 00:37:27,087 --> 00:37:31,092 strewn with minute strands of space-time. 691 00:37:33,762 --> 00:37:36,098 Kaku: Strings are extremely tiny, 692 00:37:36,099 --> 00:37:38,601 like 100 billion billion times smaller than a proton, 693 00:37:38,602 --> 00:37:40,804 so let me explain. 694 00:37:40,805 --> 00:37:44,676 Take an atom, and expand it to the size of the solar system. 695 00:37:44,677 --> 00:37:47,279 If the atom were the size of our solar system, 696 00:37:47,280 --> 00:37:49,716 then a string is much smaller than that. 697 00:37:49,717 --> 00:37:51,986 A string is the size of an atom. 698 00:37:51,987 --> 00:37:55,993 That is how incredibly tiny this all is. 699 00:37:56,593 --> 00:37:59,062 We also think that once upon a time 700 00:37:59,063 --> 00:38:03,068 the universe was the size of a string. 701 00:38:04,637 --> 00:38:06,905 When strings move, they vibrate. 702 00:38:06,906 --> 00:38:08,108 And when they vibrate, 703 00:38:08,109 --> 00:38:10,044 each note of this vibrating string 704 00:38:10,045 --> 00:38:12,013 corresponds to a particle. 705 00:38:12,014 --> 00:38:13,581 So if I had a microscope 706 00:38:13,582 --> 00:38:15,451 that could peer into an electron or proton, 707 00:38:15,452 --> 00:38:17,286 i'd see a vibrating string. 708 00:38:17,287 --> 00:38:20,625 My own body is essentially a symphony of vibrating strings. 709 00:38:20,626 --> 00:38:24,631 But when strings move, they force the space around it 710 00:38:25,899 --> 00:38:28,569 to curl up, to bend, 711 00:38:28,570 --> 00:38:31,540 exactly as Einstein had predicted. 712 00:38:31,541 --> 00:38:35,546 Narrator: Strings are the theorist's darling. 713 00:38:36,914 --> 00:38:40,919 They are a structure hatched specifically to cater 714 00:38:40,952 --> 00:38:42,721 to the discrepancies 715 00:38:42,722 --> 00:38:45,224 in the divergent theories of physics. 716 00:38:45,225 --> 00:38:49,130 True, they are wholly abstract, and have little basis 717 00:38:49,131 --> 00:38:50,699 in reality so far, 718 00:38:50,700 --> 00:38:52,568 but at least they may 719 00:38:52,569 --> 00:38:54,671 provide the ties that bind 720 00:38:54,672 --> 00:38:58,677 the two great schools of thought. 721 00:38:58,744 --> 00:39:01,213 We physicists have been puzzled by the fact 722 00:39:01,214 --> 00:39:03,183 that we have matter, like atoms, 723 00:39:03,184 --> 00:39:06,287 and we have forces, like gravity, 724 00:39:06,288 --> 00:39:07,655 that attract atoms. 725 00:39:07,656 --> 00:39:09,557 Now we realize that this dichotomy 726 00:39:09,558 --> 00:39:11,860 between force and matter 727 00:39:11,861 --> 00:39:13,896 is really not a dichotomy at all. 728 00:39:13,897 --> 00:39:17,201 These are nothing but vibrations of the same string. 729 00:39:17,202 --> 00:39:20,004 One string that vibrates could be a quark. 730 00:39:20,005 --> 00:39:22,942 Another string that vibrates could be an electron. 731 00:39:22,943 --> 00:39:24,544 But yet another string that vibrates 732 00:39:24,545 --> 00:39:28,551 could be light, a photon, or Einstein's theory of gravity. 733 00:39:28,784 --> 00:39:32,021 Narrator: String theory, at its heart, 734 00:39:32,022 --> 00:39:33,990 is a search for perfection, 735 00:39:33,991 --> 00:39:36,026 to conjure a vision of creation 736 00:39:36,027 --> 00:39:39,965 of consummate order and purity of form. 737 00:39:39,966 --> 00:39:43,972 Kaku: Now, if you look at clouds or rocks or mountains, 738 00:39:44,740 --> 00:39:47,576 we don't see symmetry at all. 739 00:39:47,577 --> 00:39:50,747 But as we go backwards in time, 740 00:39:50,748 --> 00:39:54,753 as we get closer and closer to the big bang, 741 00:39:55,420 --> 00:39:57,923 we realize that there's a beautiful, 742 00:39:57,924 --> 00:40:00,559 gorgeous, magnificent symmetry 743 00:40:00,560 --> 00:40:04,566 that we begin to see emerging as we go backwards in time. 744 00:40:09,006 --> 00:40:10,674 Now, we believe 745 00:40:10,675 --> 00:40:13,143 that at the instant of the big bang 746 00:40:13,144 --> 00:40:15,513 there was perfect symmetry. 747 00:40:15,514 --> 00:40:18,618 The only theory which gives us this perfect symmetry 748 00:40:18,619 --> 00:40:21,555 is the super string theory. 749 00:40:21,556 --> 00:40:25,561 Narrator: Theorists today are walking a fine line 750 00:40:25,561 --> 00:40:29,332 between models of the universe based on images 751 00:40:29,333 --> 00:40:31,335 we can make concrete, 752 00:40:31,336 --> 00:40:35,341 and concepts that seem, for now, beyond the imagination. 753 00:40:35,541 --> 00:40:38,277 Kaku: These equations are well-defined, 754 00:40:38,278 --> 00:40:39,746 they're well-known, 755 00:40:39,747 --> 00:40:42,249 but some people think that perhaps we humans 756 00:40:42,250 --> 00:40:44,619 are not smart enough to solve them. 757 00:40:44,620 --> 00:40:47,957 Think of a duck or a monkey. 758 00:40:47,958 --> 00:40:51,094 Why should a duck or a monkey understand calculus 759 00:40:51,095 --> 00:40:54,233 or electric fields or black holes? 760 00:40:54,234 --> 00:40:56,369 And why is it that we have the power 761 00:40:56,370 --> 00:40:59,740 to understand the big bang and the black holes? 762 00:40:59,741 --> 00:41:01,408 And then the question is, 763 00:41:01,409 --> 00:41:03,278 are we smart enough to understand 764 00:41:03,279 --> 00:41:04,813 the theory of everything? 765 00:41:04,814 --> 00:41:06,382 At the present time, no. 766 00:41:06,383 --> 00:41:09,219 Hawking: By the end of the '80s, 767 00:41:09,220 --> 00:41:12,423 I and a number of other physicists 768 00:41:12,424 --> 00:41:14,793 were beginning to wonder if string theory 769 00:41:14,794 --> 00:41:18,164 really was the ultimate theory of the universe. 770 00:41:18,165 --> 00:41:22,170 Narrator: In fact, string theory is no theory at all, 771 00:41:22,872 --> 00:41:26,676 for a theory, by definition, must venture some predictions 772 00:41:26,677 --> 00:41:30,682 that will ultimately be put to the test of reality. 773 00:41:30,682 --> 00:41:34,553 Sublime and conceptually perfect as string theory is, 774 00:41:34,554 --> 00:41:37,925 it needs someone to come to its rescue. 775 00:41:37,926 --> 00:41:39,493 Kaku: In the last several years, 776 00:41:39,494 --> 00:41:41,563 we've been in the wilderness. 777 00:41:41,564 --> 00:41:43,632 the mathematics has proven too difficult 778 00:41:43,633 --> 00:41:45,468 to solve super string theory. 779 00:41:45,469 --> 00:41:47,871 The theory is smarter than we are. 780 00:41:47,872 --> 00:41:50,775 The creative engine behind super string theory 781 00:41:50,776 --> 00:41:52,878 is ed Witten of Princeton. 782 00:41:52,879 --> 00:41:55,916 In fact, scientific american once said that Ed Witten is 783 00:41:55,917 --> 00:41:59,053 "the smartest man on earth." 784 00:41:59,054 --> 00:42:03,060 And if anyone is smart enough to solve super string theory, 785 00:42:03,126 --> 00:42:07,131 it's probably going to be Ed Witten. 786 00:42:14,442 --> 00:42:17,912 Witten: String theory is a mathematical structure 787 00:42:17,913 --> 00:42:20,649 of a richness and subtlety we don't understand well. 788 00:42:20,650 --> 00:42:23,319 There are many pieces of it that we've come to understand, 789 00:42:23,320 --> 00:42:25,054 and they, by themselves, 790 00:42:25,055 --> 00:42:26,824 are quite elaborate stories in their own right. 791 00:42:26,825 --> 00:42:29,160 We don't yet have 792 00:42:29,161 --> 00:42:31,330 a complete overview of the whole subject. 793 00:42:31,331 --> 00:42:35,035 It seemed pretty clear that if there was a chance 794 00:42:35,036 --> 00:42:38,740 to go way beyond our familiar understanding of physics, 795 00:42:38,741 --> 00:42:42,145 string theory was the most ambitious prospect. 796 00:42:42,146 --> 00:42:44,915 It also was clear then, as it is now, 797 00:42:44,916 --> 00:42:47,051 that it is a very long-term proposition. 798 00:42:47,052 --> 00:42:50,556 Narrator: Ed Witten has taken on the challenge 799 00:42:50,557 --> 00:42:52,926 of tackling some of the most difficult mathematics 800 00:42:52,927 --> 00:42:55,463 in the scientific world. 801 00:42:55,464 --> 00:42:59,469 Witten: I wasn't originally interested in maths. 802 00:42:59,536 --> 00:43:02,739 I was interested in doing physics. 803 00:43:02,740 --> 00:43:04,875 And I remember very well 804 00:43:04,876 --> 00:43:06,377 having some reticence 805 00:43:06,378 --> 00:43:07,879 for quite some time about 806 00:43:07,880 --> 00:43:10,216 making the 100% commitment, 807 00:43:10,217 --> 00:43:13,820 of really deciding that was going to be my life. 808 00:43:13,821 --> 00:43:17,827 Narrator: Witten's quest is to turn out 809 00:43:17,994 --> 00:43:21,498 countless consuming mathematical constructions. 810 00:43:21,499 --> 00:43:24,302 One, he hopes, will someday get strings 811 00:43:24,303 --> 00:43:27,540 to actually describe the world. 812 00:43:27,541 --> 00:43:29,676 Witten: The question was, 813 00:43:29,677 --> 00:43:32,713 how realistic was it as a theory of nature? 814 00:43:32,714 --> 00:43:35,717 My main interest was to make it more realistic. 815 00:43:35,718 --> 00:43:38,153 For a few years there were very exciting developments, 816 00:43:38,154 --> 00:43:39,790 and then we went through a period 817 00:43:39,791 --> 00:43:41,959 where the progress was slower and more subtle. 818 00:43:41,960 --> 00:43:43,728 We were dotting i's and crossing t's 819 00:43:43,729 --> 00:43:45,998 and understanding details. 820 00:43:45,999 --> 00:43:48,134 We were discovering things that were strange and beautiful, 821 00:43:48,135 --> 00:43:51,205 but perhaps not of such wide ramifications 822 00:43:51,206 --> 00:43:53,641 as the things done in the mid-'80s. 823 00:43:53,642 --> 00:43:57,246 So things were slow 824 00:43:57,247 --> 00:44:01,253 and the developments, I guess, were more mathematical. 825 00:44:01,420 --> 00:44:05,425 String theory, as it had developed by the mid-'80s, 826 00:44:06,827 --> 00:44:08,929 was characterized by the fact 827 00:44:08,930 --> 00:44:11,432 that there were five theories we knew about. 828 00:44:11,433 --> 00:44:14,570 And that raised the rather curious question 829 00:44:14,571 --> 00:44:16,339 which was always a little bit embarrassing. 830 00:44:16,340 --> 00:44:19,510 If one of those theories describes our universe, 831 00:44:19,511 --> 00:44:23,517 then who lives in other four universes? 832 00:44:25,185 --> 00:44:27,086 we've come to understand 833 00:44:27,087 --> 00:44:28,822 that those five theories we've been studying 834 00:44:28,823 --> 00:44:32,828 are all limiting cases of one bigger picture. 835 00:44:33,163 --> 00:44:37,168 In the last couple of years, the picture has really changed 836 00:44:38,002 --> 00:44:42,008 through something which is called duality. 837 00:44:46,714 --> 00:44:48,983 Duality is a relationship between two different theories, 838 00:44:48,984 --> 00:44:51,053 which isn't obvious. 839 00:44:51,054 --> 00:44:52,654 If it's obvious, you don't dignify it 840 00:44:52,655 --> 00:44:54,356 by the name "duality." 841 00:44:54,357 --> 00:44:56,659 So we have different pictures. 842 00:44:56,660 --> 00:44:58,496 And it's not that one is correct 843 00:44:58,497 --> 00:45:00,065 and the other one isn't correct. 844 00:45:00,066 --> 00:45:01,567 One of them is more useful 845 00:45:01,568 --> 00:45:03,168 for answering one set of questions. 846 00:45:03,169 --> 00:45:04,670 The other is more useful 847 00:45:04,671 --> 00:45:06,172 for answering another set of questions. 848 00:45:06,173 --> 00:45:07,674 And the power of the theory 849 00:45:07,675 --> 00:45:09,176 comes largely from understanding 850 00:45:09,177 --> 00:45:10,846 that these different points of view 851 00:45:10,847 --> 00:45:12,448 which sound like they're 852 00:45:12,449 --> 00:45:14,383 about different universes 853 00:45:14,384 --> 00:45:16,988 actually work together in describing one model. 854 00:45:16,989 --> 00:45:18,856 And I might say that 10 years ago 855 00:45:18,857 --> 00:45:20,759 it just looked impossible that those theories 856 00:45:20,760 --> 00:45:22,328 would turn out to all be one, 857 00:45:22,329 --> 00:45:23,830 so it's a big conceptual upheaval 858 00:45:23,831 --> 00:45:26,367 to understand that there's only one theory 859 00:45:26,368 --> 00:45:28,369 which is our candidate for nature. 860 00:45:28,370 --> 00:45:31,774 To make an analogy 861 00:45:31,775 --> 00:45:33,310 with the blind men and the elephant, 862 00:45:33,311 --> 00:45:34,978 there is the guy who discovered the trunk, 863 00:45:34,979 --> 00:45:36,815 and there's the guy who discovered the tail, 864 00:45:36,816 --> 00:45:38,650 and there's the guy who discovered the ear. 865 00:45:38,651 --> 00:45:40,152 And in the past we thought 866 00:45:40,153 --> 00:45:41,822 they were five different things. 867 00:45:41,823 --> 00:45:43,657 Now we know there is one elephant. 868 00:45:43,658 --> 00:45:47,663 We still don't understand that elephant too well. 869 00:45:49,432 --> 00:45:52,336 Narrator: Witten remains convinced 870 00:45:52,337 --> 00:45:54,672 string theory can be borne out. 871 00:45:54,673 --> 00:45:57,576 His conviction has its price. 872 00:45:57,577 --> 00:46:00,680 The new world he's charting is a lonely one. 873 00:46:00,681 --> 00:46:04,686 It is populated only by strange and abstract ideas, 874 00:46:05,688 --> 00:46:08,090 by many dimensions, 875 00:46:08,091 --> 00:46:11,862 rather than the three the rest of us know. 876 00:46:11,863 --> 00:46:14,699 A lot of people, even professional physicists, 877 00:46:14,700 --> 00:46:18,705 in my opinion, don't fully grasp the scope and richness 878 00:46:18,209 --> 00:46:20,149 of the structure involved. 879 00:46:20,150 --> 00:46:22,656 People may tend to be too impatient for quick results 880 00:46:22,657 --> 00:46:24,728 in some cases. 881 00:46:24,729 --> 00:46:27,268 I think that there are a lot of reasons 882 00:46:27,269 --> 00:46:29,574 to think that a structure 883 00:46:29,575 --> 00:46:31,546 which is so rich and so physical 884 00:46:31,547 --> 00:46:33,952 and which has been the source, 885 00:46:33,953 --> 00:46:35,890 the continued source of so many beautiful discoveries, 886 00:46:35,891 --> 00:46:39,891 must be on the right track. 887 00:46:40,069 --> 00:46:42,407 Narrator: Witten is widely regarded 888 00:46:42,408 --> 00:46:44,580 as the heir apparent to Einstein. 889 00:46:44,581 --> 00:46:47,387 On he struggles, with little assurance 890 00:46:47,388 --> 00:46:50,128 his work can be completed in his lifetime. 891 00:46:50,129 --> 00:46:53,402 Witten: When you are doing a calculation, 892 00:46:53,403 --> 00:46:56,076 it's usually on some very specific detail. 893 00:46:56,077 --> 00:46:58,583 That's a tiny, tiny piece of the big picture. 894 00:46:58,584 --> 00:47:00,755 And you're hoping that that piece will shed light 895 00:47:00,756 --> 00:47:02,393 on the big picture. 896 00:47:02,394 --> 00:47:05,802 Sometimes it does, but usually it doesn't. 897 00:47:05,803 --> 00:47:07,974 Often times you come home 898 00:47:07,975 --> 00:47:09,478 at the end of the day, 899 00:47:09,479 --> 00:47:11,316 and you know exactly the amount you knew 900 00:47:11,317 --> 00:47:12,820 at the beginning of the day. 901 00:47:12,821 --> 00:47:16,163 But sometimes you know a little bit more. 902 00:47:16,164 --> 00:47:19,404 I think that this investigation 903 00:47:19,405 --> 00:47:22,445 is the richest thing that physicists can tackle now. 904 00:47:22,446 --> 00:47:25,086 How far we'll get in our lifetimes, 905 00:47:25,087 --> 00:47:26,790 there's no way to know. 906 00:47:26,791 --> 00:47:28,729 We might get the answers we dream of getting. 907 00:47:28,730 --> 00:47:30,901 We might fall well short. 908 00:47:30,902 --> 00:47:33,274 But I think we can accomplish something, 909 00:47:33,275 --> 00:47:35,580 a faith which i'd say is well-vindicated 910 00:47:35,581 --> 00:47:38,221 by the duality revolution of the last couple of years. 911 00:47:38,222 --> 00:47:40,359 I think we can accomplish more in the future, 912 00:47:40,360 --> 00:47:44,360 and getting as far as we can is the best we can do. 913 00:47:50,754 --> 00:47:52,257 Hawking: 20 years ago, 914 00:47:52,258 --> 00:47:56,258 I said there was a 50/50 chance 915 00:47:56,703 --> 00:47:59,375 we would have a complete picture of the universe 916 00:47:59,376 --> 00:48:02,651 in the next 20 years. 917 00:48:02,652 --> 00:48:06,652 That is still my estimate today, but the 20 years starts now. 918 00:48:08,700 --> 00:48:10,438 it's very hard to build 919 00:48:10,439 --> 00:48:12,811 a fully consistent quantum theory of gravity. 920 00:48:12,812 --> 00:48:16,420 The string theorists think they have one. 921 00:48:16,421 --> 00:48:18,827 They may or may not be right. 922 00:48:18,828 --> 00:48:21,367 They haven't yet pushed their theory far enough 923 00:48:21,368 --> 00:48:23,104 so you can compare 924 00:48:23,105 --> 00:48:25,811 the consequences of string theory to experiment, 925 00:48:25,812 --> 00:48:29,812 and that's what you ultimately need. 926 00:48:30,525 --> 00:48:32,396 Narrator: While theorists around the world 927 00:48:32,397 --> 00:48:34,066 pursue their lone predictions, 928 00:48:34,067 --> 00:48:35,737 many are pinning their hopes 929 00:48:35,738 --> 00:48:37,676 on a singular mission. 930 00:48:37,677 --> 00:48:41,677 Neil Turok is preparing for a journey into the unknown. 931 00:48:43,492 --> 00:48:46,499 He's about to explore a place called the past. 932 00:48:46,500 --> 00:48:49,240 When he gets there, 933 00:48:49,241 --> 00:48:52,916 he'll tell us what it looks like. 934 00:48:52,917 --> 00:48:56,793 Turok: Imagine you were trying to navigate across a continent, 935 00:48:56,794 --> 00:49:00,602 and you had a map which only showed features 936 00:49:00,603 --> 00:49:03,978 greater than 100 miles across. 937 00:49:03,979 --> 00:49:06,317 It wouldn't be much use in finding your way 938 00:49:06,318 --> 00:49:08,590 along a particular route. 939 00:49:08,591 --> 00:49:12,591 But if you have a map that has a resolution of a mile, 940 00:49:13,504 --> 00:49:16,678 then that becomes much more useful. 941 00:49:16,679 --> 00:49:18,917 Narrator: Turok is setting out 942 00:49:18,918 --> 00:49:21,691 to make the map of all maps with a satellite 943 00:49:21,692 --> 00:49:24,866 he plans to help launch early in the 21st century. 944 00:49:24,867 --> 00:49:28,867 It's called the Planck explorer. 945 00:49:29,713 --> 00:49:32,185 Turok: what we'll do is look out, 946 00:49:32,186 --> 00:49:36,186 map the whole sky at a very high resolution. 947 00:49:49,264 --> 00:49:53,264 Basically, this is equivalent to making a map of the Earth 948 00:49:53,743 --> 00:49:56,850 where you show all the rivers and the mountains 949 00:49:56,851 --> 00:49:59,223 and the valleys in exquisite detail. 950 00:49:59,224 --> 00:50:03,224 And this map will contain a vast amount of information. 951 00:50:03,502 --> 00:50:06,242 It will give us 952 00:50:06,243 --> 00:50:08,814 the best picture we have of the universe. 953 00:50:08,815 --> 00:50:10,653 Narrator: the Planck explorer 954 00:50:10,654 --> 00:50:13,661 will be able to detect energy that was emitted 955 00:50:13,662 --> 00:50:16,000 billions of years ago at the dawn of the universe. 956 00:50:16,001 --> 00:50:18,306 For a study that has too long 957 00:50:18,307 --> 00:50:20,846 searched for answers in the mind's eye, 958 00:50:20,847 --> 00:50:24,021 it might provide a vision of sheer clarity. 959 00:50:24,022 --> 00:50:25,859 Turok: It is a map of the universe 960 00:50:25,860 --> 00:50:27,430 at very early times. 961 00:50:27,431 --> 00:50:30,772 We're not sure quite when the radiation 962 00:50:30,773 --> 00:50:34,773 from the big bang was emitted from the plasma 963 00:50:35,753 --> 00:50:38,392 in the early universe, 964 00:50:38,393 --> 00:50:41,066 but when we look out and we see the sky, 965 00:50:41,067 --> 00:50:42,938 we're looking directly 966 00:50:42,939 --> 00:50:45,177 at different patches of hot plasma, 967 00:50:45,178 --> 00:50:46,848 and they are going to be 968 00:50:46,849 --> 00:50:48,519 at slightly different temperature, 969 00:50:48,520 --> 00:50:50,390 and so this will be a map 970 00:50:50,391 --> 00:50:54,391 of the temperature variations on the sky. 971 00:51:13,251 --> 00:51:15,757 Narrator: In those subtle vestiges of the big bang 972 00:51:15,758 --> 00:51:18,497 are the secrets of its inception. 973 00:51:18,498 --> 00:51:21,439 They will bear the signature of creation, 974 00:51:21,440 --> 00:51:23,310 and with any luck, 975 00:51:23,311 --> 00:51:27,311 the revelation that will clinch which theory wins the day. 976 00:51:27,722 --> 00:51:31,722 The time may soon be at hand to know the ultimate truth. 977 00:51:34,340 --> 00:51:36,277 I think people are usually 978 00:51:36,278 --> 00:51:38,917 excessively confident about the theories, 979 00:51:38,918 --> 00:51:42,694 because there has been an absence of data, 980 00:51:42,695 --> 00:51:44,264 and that's allowed people 981 00:51:44,265 --> 00:51:46,537 to be confident about the theories. 982 00:51:46,538 --> 00:51:48,610 The current theories there are, are all based 983 00:51:48,611 --> 00:51:52,611 on very clever ideas and very imaginative ideas, 984 00:51:52,922 --> 00:51:56,531 but what's really good about them is 985 00:51:56,532 --> 00:52:00,374 they do give you a well-defined framework 986 00:52:00,375 --> 00:52:02,914 within which you can make predictions. 987 00:52:02,915 --> 00:52:06,457 Narrator: We've already glimpsed the temperature fluctuations 988 00:52:06,458 --> 00:52:09,732 of the big bang, but never in sufficient detail. 989 00:52:09,733 --> 00:52:13,733 each theory of everything predicts a different outcome 990 00:52:14,010 --> 00:52:16,015 to turok's experiment. 991 00:52:16,016 --> 00:52:19,290 Perhaps he will at last settle the question, 992 00:52:19,291 --> 00:52:23,268 or perhaps he'll only raise more. 993 00:52:23,269 --> 00:52:25,740 Turok: We're in the wonderful situation now 994 00:52:25,741 --> 00:52:27,846 where over the next 5 or 10 years, 995 00:52:27,847 --> 00:52:30,954 the theory is going to be beaten to death, 996 00:52:30,955 --> 00:52:33,460 or theories that we have will be beaten to death 997 00:52:33,461 --> 00:52:35,566 in terms of making predictions. 998 00:52:35,567 --> 00:52:37,270 That will all be settled, 999 00:52:37,271 --> 00:52:40,546 and they'll all say exactly 1000 00:52:40,547 --> 00:52:43,453 what they expect to find on the sky. 1001 00:52:43,454 --> 00:52:45,827 And then this satellite will fly 1002 00:52:45,828 --> 00:52:48,567 and will map the sky to very high precision, 1003 00:52:48,568 --> 00:52:52,568 and we'll see what happens. 1004 00:52:53,381 --> 00:52:56,320 It's a very exciting time to be involved. 1005 00:52:56,321 --> 00:53:00,164 it's a unique opportunity in science where you're told, 1006 00:53:00,165 --> 00:53:02,637 within 10 years we're going to have the data 1007 00:53:02,638 --> 00:53:05,077 that will prove or disprove 1008 00:53:05,078 --> 00:53:08,185 any theory of how structure formed in the universe. 1009 00:53:08,186 --> 00:53:11,460 And you've got 10 years, 1010 00:53:11,461 --> 00:53:15,461 so we'll see if anyone gets it right. 1011 00:53:17,110 --> 00:53:19,581 Hawking: It could be that in a few years 1012 00:53:19,582 --> 00:53:23,582 we will have a complete theory that is confirmed by experiment. 1013 00:53:24,930 --> 00:53:28,572 It would be a remarkable achievement, 1014 00:53:28,573 --> 00:53:31,913 perhaps the ultimate triumph of science. 1015 00:53:31,914 --> 00:53:35,914 But knowing how the universe works 1016 00:53:36,293 --> 00:53:39,601 is not enough to tell us why it exists. 1017 00:53:39,602 --> 00:53:43,411 To find the answer to that question 1018 00:53:43,412 --> 00:53:47,412 would be to know the mind of God. 1019 00:53:51,967 --> 00:53:55,909 To learn more about "Stephen Hawking's Universe," 1020 00:53:55,910 --> 00:53:58,550 visit PBS online at the internet address 1021 00:53:58,551 --> 00:54:02,551 on your screen. 1022 00:54:14,560 --> 00:54:18,560 -- captions by vitac -- burbank, pittsburgh, tampa, and washington, d.c. 1023 00:55:01,449 --> 00:55:03,787 "Stephen Hawking's Universe" was made possible 1024 00:55:03,788 --> 00:55:06,629 by Alfred P. Sloan foundation to enhance public understanding 1025 00:55:06,630 --> 00:55:09,135 of the role of science and technology, 1026 00:55:09,136 --> 00:55:12,644 the arthur vining davis foundations, 1027 00:55:12,645 --> 00:55:15,519 the corporation for public broadcasting, 1028 00:55:15,520 --> 00:55:17,658 and viewers like you. 1029 00:55:17,659 --> 00:55:20,398 Corporate funding is provided by Amgen, 1030 00:55:20,399 --> 00:55:23,473 unlocking the secrets of life through biotechnology. 1031 00:55:23,474 --> 00:55:25,278 At Amgen, we produce medicines 1032 00:55:25,279 --> 00:55:27,349 that improve people's lives today 1033 00:55:27,350 --> 00:55:31,350 and bring hope for tomorrow.