1 00:01:06,800 --> 00:01:09,402 Where do we come from? 2 00:01:09,836 --> 00:01:11,137 How did the universe begin? 3 00:01:15,475 --> 00:01:16,776 Why is the universe the way it is? 4 00:01:20,680 --> 00:01:22,415 Good morning. 5 00:01:22,415 --> 00:01:24,150 Welcome to Gonville and Caius, 6 00:01:24,150 --> 00:01:26,319 More commonly known as Caius College. 7 00:01:26,319 --> 00:01:30,223 Caius College was founded in 1348 8 00:01:30,223 --> 00:01:31,958 By Edmund Gonville. 9 00:01:31,958 --> 00:01:34,561 Where are we going? 10 00:01:34,561 --> 00:01:36,729 Now we come to the portrait 11 00:01:36,729 --> 00:01:38,898 Of probably our most famous caiusan, 12 00:01:39,332 --> 00:01:41,067 Professor Stephen Hawking, The world-famous cosmologist. 13 00:01:47,574 --> 00:01:49,742 Like predecessor sir Isaac Newton before him, 14 00:01:49,742 --> 00:01:51,478 He is lucasian professor of mathematics 15 00:01:51,911 --> 00:01:54,080 For the university, 16 00:01:54,080 --> 00:01:56,249 And his particular sphere Is research of the black hole 17 00:01:56,249 --> 00:01:58,418 And the history of the universe, 18 00:01:58,852 --> 00:02:01,454 Culminating in his book "The brief history of time," 19 00:02:01,454 --> 00:02:04,057 Which worldwide has sold Over 8 million copies. 20 00:02:04,491 --> 00:02:06,659 Hawking: all of my life, I have been fascinated 21 00:02:06,659 --> 00:02:09,696 By the big questions that face us, 22 00:02:09,696 --> 00:02:13,600 And have tried to find Scientific answers to them. 23 00:02:13,600 --> 00:02:17,070 Perhaps that's why I have Sold more books on physics 24 00:02:17,070 --> 00:02:18,371 Than Madonna has on sex. 25 00:02:22,275 --> 00:02:24,444 Now this is professor Hawking's study, 26 00:02:24,878 --> 00:02:27,046 Which he will use when he's In residency in college. 27 00:02:27,046 --> 00:02:30,517 He'll use this for his Tutorials or meetings 28 00:02:30,950 --> 00:02:32,252 Or any private work he needs to do. 29 00:02:36,589 --> 00:02:40,059 It is very much a personal Room with his books 30 00:02:40,059 --> 00:02:42,228 And his portraits and pictures, So it's really a home from home 31 00:02:42,228 --> 00:02:46,132 when they're in college. 32 00:02:46,566 --> 00:02:48,301 He's got an inherited disease, motor neuron disease. 33 00:02:48,301 --> 00:02:50,036 He can project his voice with a synthesizer 34 00:02:50,036 --> 00:02:51,337 Which is attached to his wheelchair. 35 00:02:57,410 --> 00:02:59,145 Hope you enjoyed your visit. Bye. Bye. 36 00:03:01,748 --> 00:03:06,519 If, like me, you have Looked at the stars 37 00:03:06,953 --> 00:03:09,556 And tried to make sense of what you see, 38 00:03:09,989 --> 00:03:13,893 You too have started to wonder what makes the universe exist. 39 00:03:14,327 --> 00:03:18,231 The questions are clear and deceptively simple, 40 00:03:18,231 --> 00:03:21,701 But the answers have always seemed well beyond our reach 41 00:03:21,701 --> 00:03:23,436 Until now. 42 00:03:32,545 --> 00:03:35,148 Narrator: our view of the universe 43 00:03:35,148 --> 00:03:38,618 Has long been shaped simply by what we could see. 44 00:03:38,618 --> 00:03:41,221 For thousands of years, that meant we understood 45 00:03:41,221 --> 00:03:44,257 Only what the naked eye could behold. 46 00:03:44,691 --> 00:03:47,727 Now, new breakthroughs In science and technology 47 00:03:47,727 --> 00:03:49,896 Are rapidly advancing our horizons. 48 00:03:57,270 --> 00:04:01,174 We are witness to the very brink of time and space. 49 00:04:08,114 --> 00:04:11,584 Hawking: I want you to share my excitement 50 00:04:11,584 --> 00:04:14,621 At the discoveries, past and present, 51 00:04:15,054 --> 00:04:18,524 Which have revolutionized the way we think. 52 00:04:18,524 --> 00:04:22,428 From the big bang to black holes, 53 00:04:22,428 --> 00:04:25,031 From dark matter to a possible big crunch, 54 00:04:25,465 --> 00:04:27,634 Our image of the universe today 55 00:04:27,634 --> 00:04:30,236 Is full of strange-sounding ideas 56 00:04:30,236 --> 00:04:33,273 And remarkable truths. 57 00:04:33,273 --> 00:04:36,743 The story of how we Arrived at this picture 58 00:04:36,743 --> 00:04:38,911 Is a story of learning to understand what we see. 59 00:04:42,382 --> 00:04:44,550 Narrator: with every century, 60 00:04:44,984 --> 00:04:47,153 Our eyes on the universe have been opened a new. 61 00:05:01,901 --> 00:05:05,371 Only 75 years ago, 62 00:05:05,805 --> 00:05:08,408 At the Mount Wilson Observatory in California, 63 00:05:08,841 --> 00:05:11,878 A young astronomer peered into a now-primitive telescope 64 00:05:12,312 --> 00:05:15,348 And forever changed our understanding of the heavens. 65 00:05:15,348 --> 00:05:18,384 His name -- Edwin Hubble. 66 00:05:22,288 --> 00:05:24,457 We know, thanks to Hubble, that 67 00:05:24,457 --> 00:05:25,758 Altogether within the limits 68 00:05:25,758 --> 00:05:27,060 Of the observable universe 69 00:05:27,493 --> 00:05:28,795 There's something like 70 00:05:28,795 --> 00:05:30,096 100 billion trillion stars. 71 00:05:30,096 --> 00:05:33,132 It's a lot of stars. 72 00:05:33,566 --> 00:05:35,301 And we now know thanks to recent discoveries 73 00:05:35,301 --> 00:05:37,470 -Very recent discoveries also 74 00:05:37,904 --> 00:05:40,940 What we had believed But had no proof of, 75 00:05:41,374 --> 00:05:43,109 And that is that many of those stars have planets. 76 00:05:43,109 --> 00:05:44,844 So there are countless trillions of planets 77 00:05:45,278 --> 00:05:45,712 In the observable universe. 78 00:05:53,086 --> 00:05:54,821 Narrator: this was among Hubble's 79 00:05:55,254 --> 00:05:56,989 Most striking contributions 80 00:05:57,423 --> 00:06:00,026 Even as it was for his predecessors. 81 00:06:00,026 --> 00:06:02,195 The more we learn about the universe, 82 00:06:02,628 --> 00:06:05,231 The humbler the role We seem to play in it. 83 00:06:05,231 --> 00:06:07,834 Jastrow: two-thirds of The stars and planets 84 00:06:07,834 --> 00:06:10,436 And life, if it's there, in the universe 85 00:06:10,436 --> 00:06:12,605 Are billions of years older than we are. 86 00:06:13,039 --> 00:06:15,208 And if you ask what a billion years means 87 00:06:15,208 --> 00:06:16,943 In the history of life, I must tell you 88 00:06:16,943 --> 00:06:18,678 That a billion years ago 89 00:06:18,678 --> 00:06:20,847 The highest form of life on the earth was a worm. 90 00:06:21,280 --> 00:06:23,015 Three billion years ago, 91 00:06:23,015 --> 00:06:23,883 The highest form of life on the earth were bacteria. 92 00:06:27,787 --> 00:06:29,956 So we must ask ourselves, 93 00:06:29,956 --> 00:06:31,691 We who are so proud of our accomplishments, 94 00:06:32,125 --> 00:06:35,161 What is our place in the cosmic perspective of life 95 00:06:35,161 --> 00:06:37,764 If most of those beings out there, 96 00:06:37,764 --> 00:06:39,932 If they are there, stand in relationship to us 97 00:06:40,366 --> 00:06:42,101 As we do to the worms on this planet? 98 00:06:42,101 --> 00:06:44,704 And that is not meant to be a denigrating remark, 99 00:06:45,138 --> 00:06:47,740 But only to suggest that humankind's greatest experiences 100 00:06:48,174 --> 00:06:49,475 Still lie ahead of us. 101 00:06:55,548 --> 00:06:58,584 Narrator: it was the sumerians and babylonians 102 00:06:58,584 --> 00:07:01,187 Who first studied the workings of the heavens. 103 00:07:01,187 --> 00:07:03,790 Tions laid the groundwork 104 00:07:04,223 --> 00:07:06,826 For the ancient greeks who followed. 105 00:07:07,260 --> 00:07:09,429 They could see the stars 106 00:07:09,760 --> 00:07:12,465 And wonder about the sky and the heavens 107 00:07:12,899 --> 00:07:15,067 But they had very little information indeed -- 108 00:07:15,067 --> 00:07:16,803 Just what their eyes could pick up. 109 00:07:25,044 --> 00:07:28,514 They thought that everything they knew came out of the water. 110 00:07:28,514 --> 00:07:32,418 Obviously water was a very important substance, 111 00:07:32,852 --> 00:07:38,925 And so they gave water a sort of cosmic significance. 112 00:07:38,925 --> 00:07:41,527 They thought that the heavens are made of many holes, 113 00:07:41,527 --> 00:07:43,696 And these holes represented the stars, 114 00:07:43,696 --> 00:07:46,732 And just behind they had this divine fire. 115 00:07:52,371 --> 00:07:54,540 Narrator: the greeks had long explained what they saw 116 00:07:54,974 --> 00:07:56,709 With myths and legends. 117 00:07:56,709 --> 00:08:00,613 Now they began to use reason. 118 00:08:00,613 --> 00:08:04,517 Cotsakis: they thought that they had to find 119 00:08:04,951 --> 00:08:07,987 A more accurate way of expressing 120 00:08:08,421 --> 00:08:11,023 Their views about the universe, 121 00:08:11,457 --> 00:08:16,229 And that way dramatically turned out to be mathematics 122 00:08:16,229 --> 00:08:19,265 Narrator: the science of logic was born, 123 00:08:19,265 --> 00:08:22,735 And long-held assumptions were called into question. 124 00:08:23,169 --> 00:08:25,338 Cotsakis: when you see from the distance 125 00:08:25,338 --> 00:08:27,940 A boat coming, 126 00:08:27,940 --> 00:08:30,109 You don't see the whole boat in the beginning, 127 00:08:30,543 --> 00:08:34,013 But you gradually see the boat appearing 128 00:08:34,447 --> 00:08:39,218 From the horizon as if it was raising up from the sea. 129 00:08:39,218 --> 00:08:41,387 So in this way they questioned the view 130 00:08:41,387 --> 00:08:42,255 That the earth was flat. 131 00:08:46,158 --> 00:08:47,894 Narrator: proof that the earth was round 132 00:08:48,327 --> 00:08:50,062 Would have to be persuasive. 133 00:08:50,062 --> 00:08:51,797 A philosopher named Eratosthenes 134 00:08:51,797 --> 00:08:54,400 Devised one of the first scientific experiments. 135 00:08:58,738 --> 00:09:00,907 Identical objects on a flat earth 136 00:09:00,907 --> 00:09:03,943 Should cast identical shadows. 137 00:09:04,377 --> 00:09:05,678 So at the same time of day, 138 00:09:05,678 --> 00:09:07,413 In two places miles apart, 139 00:09:07,847 --> 00:09:09,148 He put this to the test. 140 00:09:12,618 --> 00:09:15,655 It was a beautiful way that he discovered 141 00:09:16,088 --> 00:09:17,823 Where he used two sticks. 142 00:09:22,161 --> 00:09:27,366 He noticed that the rays coming from the sun 143 00:09:27,366 --> 00:09:30,403 Produced different amounts of shade 144 00:09:30,836 --> 00:09:31,704 In each of the two sticks. 145 00:09:35,608 --> 00:09:38,210 Narrator: since each peg cast shadows of different lengths 146 00:09:38,210 --> 00:09:41,681 The earth's surface had to be curved. 147 00:09:41,681 --> 00:09:46,886 From the angle of the shadows, Eratosthenes could estimate 148 00:09:46,886 --> 00:09:50,790 The earth's circumference at 25,000 miles -- 149 00:09:51,223 --> 00:09:52,525 Less than 100 miles off today's measurements. 150 00:09:56,429 --> 00:10:02,068 To its first students, 151 00:10:02,501 --> 00:10:04,236 The earth itself submitted to its laws. 152 00:10:21,153 --> 00:10:23,756 Mathematics was the discipline 153 00:10:23,756 --> 00:10:26,792 That endowed the greeks with ultimate truths. 154 00:10:27,226 --> 00:10:28,527 Cotsakis: they realized 155 00:10:28,961 --> 00:10:31,998 That they can use mathematics to develop 156 00:10:31,998 --> 00:10:35,034 Theories and applications 157 00:10:35,468 --> 00:10:36,769 To all sorts of different kinds of phenomena. 158 00:10:42,842 --> 00:10:45,878 Hawking: but mathematically beautiful theories 159 00:10:45,878 --> 00:10:49,348 Are not always supported by observation. 160 00:10:49,348 --> 00:10:52,385 In the earliest days of astronomy, 161 00:10:52,818 --> 00:10:54,987 The ancient greeks found the heavens 162 00:10:54,987 --> 00:10:58,024 Less perfect than they had first imagined. 163 00:10:58,457 --> 00:11:00,626 Looking at the skies more closely, 164 00:11:00,626 --> 00:11:02,795 they began to see stars move 165 00:11:02,795 --> 00:11:04,964 in a way which defined their logic. 166 00:11:04,964 --> 00:11:10,603 If every night you go out 167 00:11:11,037 --> 00:11:15,374 And you have a careful look seeing towards south, 168 00:11:15,808 --> 00:11:18,411 after two or three days 169 00:11:18,844 --> 00:11:21,881 if you watch again you'll see five stars. 170 00:11:21,881 --> 00:11:24,917 And this is something unusual 171 00:11:24,917 --> 00:11:27,953 in respect to the other stars of the sky 172 00:11:27,953 --> 00:11:30,990 which don't change any position. 173 00:11:31,424 --> 00:11:37,930 They look as moving from west towards the east. 174 00:11:37,930 --> 00:11:43,135 Sometime they look staying still. 175 00:11:43,135 --> 00:11:47,907 Then they begin to move from the east towards the west 176 00:11:50,943 --> 00:11:53,112 Narrator: the greeks had identified 177 00:11:53,112 --> 00:11:55,715 five heavenly bodies that neighbored us. 178 00:11:56,148 --> 00:11:58,751 They dubbed them "Planetos" or "Wanderers." 179 00:12:03,522 --> 00:12:06,992 They believed in a universe in perfect balance. 180 00:12:06,992 --> 00:12:08,728 The planets, they were convinced, 181 00:12:08,728 --> 00:12:10,896 were precise globes, 182 00:12:10,896 --> 00:12:13,933 traveling in sublime circular orbits. 183 00:12:13,933 --> 00:12:16,969 But observation said otherwise 184 00:12:16,969 --> 00:12:21,307 It was the astronomer Ptolemy 185 00:12:21,307 --> 00:12:23,476 Who tried to explain the discrepancy with math. 186 00:12:27,813 --> 00:12:29,982 He made adjustments to the planets' orbits, 187 00:12:30,416 --> 00:12:33,886 retracing their paths as circles within circles, 188 00:12:34,320 --> 00:12:36,922 All neatly fitting within a sphere of fixed stars. 189 00:12:36,922 --> 00:12:38,224 At the center of the universe -- 190 00:12:38,224 --> 00:12:40,826 The Earth. 191 00:12:41,260 --> 00:12:44,296 Ptolemy lived over a century after the death of Christ. 192 00:12:44,730 --> 00:12:47,767 The new christian church 193 00:12:48,200 --> 00:12:50,803 was quick to seize upon a model of the universe 194 00:12:51,237 --> 00:12:54,707 That imagined us, God's pride, at its center. 195 00:12:55,141 --> 00:12:58,177 Papathanassiou: the cosmology of the church 196 00:12:58,177 --> 00:13:00,780 is the cosmology of the Genesis, 197 00:13:00,780 --> 00:13:06,418 and if something has the same ideas 198 00:13:06,852 --> 00:13:11,190 as they are described In "Genesis," it's okay. 199 00:13:15,528 --> 00:13:18,998 For those who could understand 200 00:13:18,998 --> 00:13:22,034 the mathematics of Ptolemy's model, 201 00:13:22,034 --> 00:13:24,637 well, it's a model which can foretell 202 00:13:25,070 --> 00:13:27,239 the position of the planets 203 00:13:27,673 --> 00:13:31,143 with an accuracy which is satisfying. 204 00:13:31,143 --> 00:13:35,481 And on the other hand there is nothing 205 00:13:35,808 --> 00:13:40,686 which can contradict the idea of the genesis. 206 00:13:45,891 --> 00:13:49,361 3, 2, 1, zero, 207 00:13:49,795 --> 00:13:52,832 Liftoff! 208 00:13:53,265 --> 00:13:55,434 Hawking: today, the claims of the scriptures 209 00:13:55,868 --> 00:13:58,470 are being put to the test 210 00:13:58,470 --> 00:14:01,073 By experiments launched into the heavens. 211 00:14:05,845 --> 00:14:08,881 Steady improvements in technology over the years 212 00:14:08,881 --> 00:14:11,917 have enabled us to test our theories 213 00:14:11,917 --> 00:14:14,086 about the universe. 214 00:14:14,086 --> 00:14:16,689 But before such detailed 215 00:14:16,689 --> 00:14:19,291 observational evidence was available, 216 00:14:19,291 --> 00:14:21,894 belief in any theory was often 217 00:14:21,894 --> 00:14:24,496 as much a matter of faith and conviction 218 00:14:28,400 --> 00:14:30,569 Ptolemy's model of the universe 219 00:14:30,569 --> 00:14:35,774 went virtually unchallenged for 1,500 years, 220 00:14:36,208 --> 00:14:38,377 supported all the time by the church, 221 00:14:38,811 --> 00:14:42,715 which was at that time the repository of learning 222 00:14:42,715 --> 00:14:47,052 Lord, receive our gifts. 223 00:14:47,052 --> 00:14:49,655 Let our offerings make us holy 224 00:14:50,089 --> 00:14:50,956 And bring us salvation. 225 00:15:13,078 --> 00:15:15,247 Narrator: Ptolemy's vision prevailed 226 00:15:15,681 --> 00:15:18,284 of a universe that acknowledged our supremacy 227 00:15:18,284 --> 00:15:22,187 of an earth that, after all, 228 00:15:22,187 --> 00:15:30,863 did not seem to move. 229 00:15:31,297 --> 00:15:33,032 And if simple experience weren't enough 230 00:15:33,032 --> 00:15:36,068 to lend Ptolemy credence, 231 00:15:36,068 --> 00:15:38,237 he had the support of the authorities as well 232 00:15:41,273 --> 00:15:43,442 The catholic church, by and large, 233 00:15:43,442 --> 00:15:46,912 through the centuries, say, from Ptolemy 234 00:15:46,912 --> 00:15:49,376 For 1,000 years -- A bit more -- 235 00:15:49,376 --> 00:15:52,985 Was the educated world. 236 00:15:52,985 --> 00:15:55,587 Ptolemy thought that it wasn't really sensible 237 00:15:55,587 --> 00:15:58,624 to have anything but the earth as the center, not so much 238 00:15:58,624 --> 00:16:01,226 for astronomical reasons, but because, after all, 239 00:16:01,660 --> 00:16:03,395 if you're not used to it, it does seem incredible 240 00:16:03,395 --> 00:16:05,130 that the earth can be moving 241 00:16:05,130 --> 00:16:07,299 And Ptolemy catalogued 242 00:16:07,733 --> 00:16:08,600 quite a few of the obvious reasons 243 00:16:09,034 --> 00:16:10,769 which affront common sense 244 00:16:11,040 --> 00:16:12,938 Like, why aren't we hurled off a rotating earth? 245 00:16:12,938 --> 00:16:13,806 How could the birds fly if there was a constant gale blowing? 246 00:16:14,239 --> 00:16:15,975 and so on. 247 00:16:16,408 --> 00:16:19,445 So that, I think, weighed fairly heavily with Ptolemy. 248 00:16:19,878 --> 00:16:23,782 Narrator: by the 16th century, Ptolemy's followers were faced 249 00:16:24,216 --> 00:16:26,819 with increasingly contradictory observations 250 00:16:27,252 --> 00:16:29,421 The church's teachings would soon enough be undone 251 00:16:29,855 --> 00:16:32,891 by one of its own scholar-priests. 252 00:16:33,325 --> 00:16:35,060 Sharratt: Nicholas Copernicus was a church man 253 00:16:35,494 --> 00:16:36,795 Not just in the sense he was catholic, 254 00:16:37,229 --> 00:16:38,530 but he actually held 255 00:16:38,964 --> 00:16:41,133 a church office as a canon 256 00:16:41,567 --> 00:16:43,736 of a cathedral. 257 00:16:43,736 --> 00:16:48,941 He had a great admiration for Ptolemaic astronomy. 258 00:16:52,411 --> 00:16:54,580 Lacked a certain elegance for Copernicus 259 00:16:54,580 --> 00:16:56,749 He found he could better explain observations 260 00:16:56,749 --> 00:16:58,917 if he made one staggering shift. 261 00:16:58,917 --> 00:17:01,520 He put the sun, 262 00:17:01,520 --> 00:17:04,990 not the earth, the center of the universe. 263 00:17:04,990 --> 00:17:09,762 Hawking: it was a revolutionary moment for cosmology. 264 00:17:10,112 --> 00:17:12,798 Copernicus had radically re-organized 265 00:17:13,232 --> 00:17:18,871 the model of the universe which had lasted for centuries. 266 00:17:18,871 --> 00:17:21,040 He began an irreversible process 267 00:17:21,473 --> 00:17:23,642 that has downgraded us from the center of the universe 268 00:17:23,642 --> 00:17:25,811 to the outer suburbs 269 00:17:25,811 --> 00:17:29,281 of one among billions of galaxies. 270 00:17:32,751 --> 00:17:34,920 Narrator: for the church, though, 271 00:17:34,920 --> 00:17:36,221 Copernicus' model amounted to heresy. 272 00:17:39,691 --> 00:17:41,860 God had put man on earth, 273 00:17:41,860 --> 00:17:43,595 and the earth at the hub of his creation. 274 00:17:51,403 --> 00:17:54,006 Copernicus died in 1543, 275 00:17:54,006 --> 00:17:58,777 his life's work dismissed but not forgotten. 276 00:17:58,777 --> 00:18:00,079 Some 60 years later, 277 00:18:00,946 --> 00:18:03,115 Johannes Kepler, a german mathematician, 278 00:18:03,115 --> 00:18:06,585 took up his work. 279 00:18:06,585 --> 00:18:10,055 Sharratt: he broke with 2,000 years 280 00:18:10,055 --> 00:18:12,658 of philosophical and astronomical tradition. 281 00:18:13,092 --> 00:18:16,562 What Kepler finished up with was non-circular motion. 282 00:18:16,562 --> 00:18:20,899 He realized that the planets 283 00:18:21,333 --> 00:18:23,936 are actually traveling in elliptical orbits. 284 00:18:24,369 --> 00:18:26,538 The great thing about Kepler's system 285 00:18:26,538 --> 00:18:29,141 is he can do everything Copernicus did 286 00:18:29,575 --> 00:18:33,045 , simply with the one clear curve of the ellipse 287 00:18:33,479 --> 00:18:34,780 in a colossal achievement. 288 00:18:39,118 --> 00:18:41,720 Narrator: at first, the church failed to comprehend 289 00:18:41,720 --> 00:18:43,455 the dramatic change coming 290 00:18:43,889 --> 00:18:45,624 but when Galileo Galilei, An italian scientist, 291 00:18:45,624 --> 00:18:47,793 dared to publish 292 00:18:47,793 --> 00:18:49,962 Copernicus' heretical idea 293 00:18:50,395 --> 00:18:53,866 the Vatican took action. 294 00:18:54,299 --> 00:18:57,769 Man: we are now at the top Floor of the villa Il Juliello 295 00:18:58,203 --> 00:19:00,372 in the place where Galileo 296 00:19:00,372 --> 00:19:04,276 spent his last 10, 15 years of life, 297 00:19:04,276 --> 00:19:07,746 the most dramatic part of his life, 298 00:19:08,180 --> 00:19:11,216 as a prisoner being condemned not to leave the house, 299 00:19:11,216 --> 00:19:14,253 not to receive guests. 300 00:19:14,253 --> 00:19:17,289 And that's why this was a place at the beginning very happy, 301 00:19:17,289 --> 00:19:19,892 at the end, very sad for him 302 00:19:20,325 --> 00:19:24,229 Isolation was torment for Galileo 303 00:19:24,229 --> 00:19:26,832 but, in solitude, his studies came into sharp focus. 304 00:19:29,868 --> 00:19:33,338 The only work he could perform 305 00:19:33,772 --> 00:19:37,242 during the period in which he was prisoner 306 00:19:37,242 --> 00:19:39,845 in his own house, was the completion 307 00:19:39,845 --> 00:19:42,447 of the laws of motion. 308 00:19:42,447 --> 00:19:44,183 Narrator: Kepler's model 309 00:19:44,616 --> 00:19:46,351 had raised some boggling questions. 310 00:19:46,351 --> 00:19:48,954 For day to follow night, 311 00:19:48,954 --> 00:19:51,990 the earth would have to rotate at a thousand miles an hour. 312 00:19:51,990 --> 00:19:56,328 Why, then, didn't we fall off? 313 00:19:56,328 --> 00:19:57,629 Your first impression Everybody, 314 00:19:58,063 --> 00:20:00,666 a kid for instance, 5 years old, 315 00:20:00,666 --> 00:20:02,401 not yet going to school, 316 00:20:02,834 --> 00:20:04,136 you ask him if the earth is in motion, 317 00:20:04,136 --> 00:20:06,305 he will say no. 318 00:20:06,738 --> 00:20:09,341 He will not have any idea, any possible idea. 319 00:20:09,341 --> 00:20:11,510 This is what was the situation , not just for kids, 320 00:20:11,944 --> 00:20:12,811 but for everybody time of Galileo. 321 00:20:18,016 --> 00:20:18,884 Narrator: that the earth was moving, 322 00:20:19,318 --> 00:20:23,222 Galileo had no doubt. 323 00:20:23,655 --> 00:20:26,258 He realized we were unaware of its motion 324 00:20:26,258 --> 00:20:30,596 simply because as it moved we moved with it. 325 00:20:31,029 --> 00:20:34,499 But he could not explain what force 326 00:20:34,933 --> 00:20:36,235 keeps us fixed to its surface. 327 00:20:40,138 --> 00:20:42,307 [ Bells ring ] 328 00:20:46,211 --> 00:20:48,814 As he studied the laws of motion, 329 00:20:48,814 --> 00:20:52,718 Galileo longed for a clearer view of the firmament. 330 00:20:52,718 --> 00:20:54,886 Galuzzi: at the end of 1609 he heard 331 00:20:55,320 --> 00:20:57,923 that there were into the market 332 00:20:58,357 --> 00:21:02,694 some funny objects which were a tube with some glasses, 333 00:21:02,694 --> 00:21:04,863 were giving some funny performance. 334 00:21:08,333 --> 00:21:09,635 This instrument 335 00:21:10,068 --> 00:21:11,803 was coming from Holland 336 00:21:11,803 --> 00:21:14,840 and was sold as a toy. 337 00:21:15,274 --> 00:21:18,310 When Galileo took it, it began to be transformed 338 00:21:18,310 --> 00:21:20,479 from a toy to an instrument. 339 00:21:20,479 --> 00:21:22,214 He started to use 340 00:21:22,648 --> 00:21:23,949 the magnification power of the telescope 341 00:21:24,383 --> 00:21:26,118 to look at the skies. 342 00:21:26,118 --> 00:21:29,588 This is a major step in his career 343 00:21:29,588 --> 00:21:31,323 qnd also in the history of modern cosmology. 344 00:21:36,094 --> 00:21:40,866 Narrator: this novelty trinket, remodeled as a scientific tool 345 00:21:40,866 --> 00:21:45,203 was to revolutionize our vision of the heavens. 346 00:21:45,637 --> 00:21:49,975 At once, Galileo was witness to worlds we had only imagined 347 00:21:50,409 --> 00:21:53,011 According to the church, 348 00:21:53,445 --> 00:21:55,180 they should have been perfect spheres 349 00:21:55,180 --> 00:21:56,915 orbiting the earth. 350 00:21:57,349 --> 00:21:59,951 They were not. 351 00:21:59,951 --> 00:22:03,422 Galuzzi: the moon was not so polished 352 00:22:03,855 --> 00:22:06,892 and so round as people believed, 353 00:22:06,892 --> 00:22:09,061 but they were presented 354 00:22:09,494 --> 00:22:11,229 valleys and mountains exactly as the earth. 355 00:22:11,229 --> 00:22:14,700 And he moved afterwards to other bodies. 356 00:22:15,133 --> 00:22:18,560 He started to observe Mercury, Mars -- 357 00:22:18,560 --> 00:22:22,074 But he was captured by Jupiter 358 00:22:22,074 --> 00:22:23,809 He started to observe, seriously, 359 00:22:23,809 --> 00:22:25,977 Jupiter in january 1610, 360 00:22:26,411 --> 00:22:29,014 and his diary note is very touching. 361 00:22:29,014 --> 00:22:31,616 It says, "I have discovered a funny body, 362 00:22:31,616 --> 00:22:34,219 something like that which is circulating around Jupiter," 363 00:22:34,653 --> 00:22:36,822 7 january, if i remember correctly. 364 00:22:36,822 --> 00:22:38,990 And the day after, 365 00:22:39,424 --> 00:22:39,858 he was immediately at the sunset at the telescope 366 00:22:46,365 --> 00:22:50,702 Narrator: struck with disbelief, he sketched what he saw. 367 00:22:50,702 --> 00:22:55,474 Galuzzi: in a few days he became aware 368 00:22:55,474 --> 00:22:59,378 that those moons as he called them were four, 369 00:22:59,378 --> 00:23:02,414 and they were satellites because they were doing 370 00:23:02,414 --> 00:23:07,185 rhythmic and cyclic performances around the body of Jupiter 371 00:23:07,185 --> 00:23:10,222 Narrator: something orbiting Jupiter 372 00:23:10,560 --> 00:23:14,126 could not be orbiting Earth. 373 00:23:14,126 --> 00:23:16,672 The church's model of the Universe was shattered. 374 00:23:18,897 --> 00:23:20,198 This was the decisive step why Galileo became convinced 375 00:23:20,198 --> 00:23:23,668 so he started to publish 376 00:23:24,102 --> 00:23:27,572 and started to produce work saying, be careful. 377 00:23:27,572 --> 00:23:29,307 We cannot stay anymore with Ptolemy. 378 00:23:29,307 --> 00:23:31,910 What the bible was saying in many times 379 00:23:32,344 --> 00:23:35,380 about the position of the sun 380 00:23:35,380 --> 00:23:37,549 and the motion of the sun around the Earth 381 00:23:37,549 --> 00:23:40,032 was not tenable anymore. 382 00:23:40,585 --> 00:23:43,188 Galileo entered a fight with the authorities. 383 00:23:43,622 --> 00:23:45,791 The book of Copernicus was suspended 384 00:23:46,224 --> 00:23:49,600 and sent to correction. 385 00:23:49,600 --> 00:23:53,165 Galileo was called to Rome at the tribunal of inquisition 386 00:23:53,165 --> 00:23:56,635 Finally he was condemned. 387 00:24:00,105 --> 00:24:03,141 Narrator: threatened with death at the stake, 388 00:24:03,141 --> 00:24:05,744 Galileo retracted his claims 389 00:24:05,744 --> 00:24:09,214 He was sentenced to spend the rest of his life 390 00:24:09,214 --> 00:24:12,684 under house arrest. 391 00:24:13,056 --> 00:24:15,287 Galuzzi: it's the beginning of the conflict 392 00:24:15,287 --> 00:24:17,022 between science and religion 393 00:24:17,022 --> 00:24:20,768 science and theology, 394 00:24:20,768 --> 00:24:23,094 and it's a tension which is going to be 395 00:24:23,094 --> 00:24:25,697 many other episodes during the modern age. 396 00:24:33,071 --> 00:24:35,674 Narrator: Galileo's voice could be stilled, 397 00:24:35,674 --> 00:24:39,144 but his spirit could not. 398 00:24:39,144 --> 00:24:41,746 The spark he lit caught fire and for those who followed 399 00:24:42,180 --> 00:24:45,650 Observing the sky became a consuming quest. 400 00:24:46,084 --> 00:24:49,554 To this day, we peer into space 401 00:24:49,988 --> 00:24:53,024 with the same sense of wonder he felt. 402 00:24:57,362 --> 00:25:01,700 Observing is almost mystical. 403 00:25:01,700 --> 00:25:05,170 It's the act that really puts me in contact 404 00:25:05,604 --> 00:25:08,206 with the rest of the universe. 405 00:25:08,206 --> 00:25:10,375 I often think if somebody's looking back at me -- 406 00:25:10,375 --> 00:25:16,014 I wonder if their telescope is bigger than mine. 407 00:25:16,014 --> 00:25:19,050 Narrator: today's telescopes depend in part 408 00:25:19,392 --> 00:25:21,219 on refinements introduced 409 00:25:21,653 --> 00:25:23,388 by a man born the year Galileo died -- 410 00:25:23,822 --> 00:25:26,858 Isaac Newton. 411 00:25:27,292 --> 00:25:29,461 Hawking: I feel I have links To both Newton and Galileo. 412 00:25:29,461 --> 00:25:33,365 I now hold the same professorship at Cambridge 413 00:25:33,365 --> 00:25:37,702 That Newton once held, 414 00:25:37,702 --> 00:25:41,606 And I was born 300 years to The day after Galileo died. 415 00:25:41,606 --> 00:25:43,341 But at least 416 00:25:43,341 --> 00:25:45,944 half a million other babies 417 00:25:45,944 --> 00:25:46,811 were born that day. 418 00:25:58,523 --> 00:26:00,692 Man: Isaac Newton 419 00:26:00,692 --> 00:26:03,728 Was born here in this house in Woolsthorpe 420 00:26:03,728 --> 00:26:07,198 on Christmas day, 1642. 421 00:26:07,198 --> 00:26:10,235 Newton, by all accounts, was a very difficult man. 422 00:26:10,235 --> 00:26:13,271 His father died 423 00:26:13,271 --> 00:26:15,440 before he was born. 424 00:26:15,440 --> 00:26:17,175 His mother 425 00:26:17,609 --> 00:26:19,344 the rather rich rector in the neighboring village. 426 00:26:19,778 --> 00:26:22,380 Newton was left here in Woolsthorpe 427 00:26:22,380 --> 00:26:24,983 at the age of 3, 428 00:26:24,983 --> 00:26:26,718 and was brought up for the next seven or eight years 429 00:26:27,152 --> 00:26:29,754 by his grandmother. 430 00:26:29,754 --> 00:26:31,056 So I think he probably had a sense of insecurity. 431 00:26:41,032 --> 00:26:44,502 Narrator: the year was 1660. 432 00:26:44,502 --> 00:26:46,237 The world of astronomy was filled with questions 433 00:26:46,237 --> 00:26:48,406 and ripe for change. 434 00:26:48,406 --> 00:26:53,178 Barbour : at Cambridge, more or less by chance, 435 00:26:53,178 --> 00:26:55,347 he picked up about four or five books on mathematics, 436 00:26:55,347 --> 00:26:57,082 and he set to work to read them. 437 00:26:57,082 --> 00:27:00,118 Six months later he was making 438 00:27:00,118 --> 00:27:02,721 important contributions to mathematics. 439 00:27:03,154 --> 00:27:04,889 18 months later he was 440 00:27:04,889 --> 00:27:06,191 the greatest mathematician alive. 441 00:27:06,625 --> 00:27:08,793 It's just staggering. 442 00:27:09,227 --> 00:27:10,962 He taught himself, just from four or five books 443 00:27:11,396 --> 00:27:13,131 and it all came out of that. 444 00:27:18,336 --> 00:27:20,939 Narrator: Newton didn't lack ambition. 445 00:27:20,939 --> 00:27:23,108 He set his sights on tackling mysteries 446 00:27:23,541 --> 00:27:25,276 Galileo had left unsolved. 447 00:27:25,276 --> 00:27:27,445 He bettered his chances 448 00:27:27,445 --> 00:27:30,915 by incorporating an internal mirror in the telescope, 449 00:27:30,915 --> 00:27:32,651 doubling its power. 450 00:27:33,084 --> 00:27:33,952 Barbour: the news of this telescope 451 00:27:34,386 --> 00:27:35,687 was distributed around Europe, 452 00:27:36,121 --> 00:27:38,723 and that's actually what made his name. 453 00:27:39,157 --> 00:27:41,760 And later on, that design of telescope 454 00:27:41,760 --> 00:27:43,495 turned out to be the best one of all 455 00:27:43,928 --> 00:27:46,531 for studying the heavens, 456 00:27:46,531 --> 00:27:51,302 so in that way he greatly advanced astronomy. 457 00:27:51,302 --> 00:27:53,471 Newton had been at Cambridge for several years 458 00:27:53,792 --> 00:27:55,640 when the plague forced him 459 00:27:56,074 --> 00:27:58,243 To come back home here to Woolsthorpe. 460 00:27:58,243 --> 00:27:59,978 And at the time he'd left Cambridge, 461 00:28:01,279 --> 00:28:03,448 he was beginning to think about the laws of motion, 462 00:28:03,448 --> 00:28:07,352 how things are moving, 463 00:28:07,352 --> 00:28:09,954 and he had the idea that basically things 464 00:28:09,954 --> 00:28:11,256 would essentially move in a straight line 465 00:28:11,690 --> 00:28:12,123 if they were left on their own 466 00:28:18,630 --> 00:28:20,799 He was beginning to think about the forces 467 00:28:20,799 --> 00:28:23,401 that might be at work, 468 00:28:23,835 --> 00:28:26,438 and one of the most obvious is the pull of gravity, 469 00:28:26,438 --> 00:28:29,040 which is pulling an object towards the earth. 470 00:28:29,040 --> 00:28:33,378 Narrator: Newton's discovery became the stuff of myth.. 471 00:28:33,812 --> 00:28:36,848 Remember the story of the apple falling from a tree? 472 00:28:37,282 --> 00:28:39,451 I think it probably is true 473 00:28:39,451 --> 00:28:41,186 that he did start thinking about these thing 474 00:28:41,186 --> 00:28:43,788 from seeing apples fall, 475 00:28:43,788 --> 00:28:46,391 but I'm absolutely certain he didn't have 476 00:28:46,825 --> 00:28:48,560 the complete theory of universal gravitation 477 00:28:48,993 --> 00:28:51,162 back here in the plague year 478 00:28:51,162 --> 00:28:52,897 and the full working out came much later. 479 00:28:56,367 --> 00:28:58,970 His idea of gravity -- 480 00:28:58,970 --> 00:29:01,573 and he called it universal gravity 481 00:29:01,573 --> 00:29:03,308 because that is a very important thing -- 482 00:29:03,308 --> 00:29:05,477 Is that every single piece of matter in the universe 483 00:29:05,910 --> 00:29:08,513 pulls every other piece 484 00:29:08,513 --> 00:29:14,152 of matter in the universe towards it, and vice versa 485 00:29:14,586 --> 00:29:17,188 The earth is billions of times more massive than the apple, 486 00:29:17,188 --> 00:29:19,357 so basically the earth is moving 487 00:29:19,648 --> 00:29:22,393 ever so slightly towards the apple, 488 00:29:22,393 --> 00:29:24,562 but you just can't see that. 489 00:29:24,996 --> 00:29:26,297 The motion of the apple is much more pronounced 490 00:29:26,731 --> 00:29:27,165 than that of the Earth. 491 00:29:31,936 --> 00:29:37,142 The importance of the apple is that it symbolizes the idea 492 00:29:37,142 --> 00:29:40,612 that the laws of nature that are working on the Earth 493 00:29:40,612 --> 00:29:43,214 are also working throughout the whole universe. 494 00:29:43,214 --> 00:29:46,251 Narrator: Newton's crowning achievement 495 00:29:46,251 --> 00:29:48,419 was to unite all that had preceded him. 496 00:29:48,419 --> 00:29:50,155 He applied his theory of gravity 497 00:29:50,155 --> 00:29:51,890 to the heavens Kepler described, 498 00:29:52,323 --> 00:29:56,227 then united Galileo's laws with his own. 499 00:29:56,661 --> 00:29:58,396 He described the path of the moon around the earth 500 00:29:58,396 --> 00:30:01,432 then looked beyond. 501 00:30:01,432 --> 00:30:04,469 Barbour: and that was enough to give Newton the hints 502 00:30:04,903 --> 00:30:07,505 to then apply those same techniques of Galileo, 503 00:30:07,505 --> 00:30:09,674 but now to the planets. 504 00:30:10,108 --> 00:30:12,277 And that essentially was the whole of the universe. 505 00:30:12,710 --> 00:30:16,181 Narrator: with one sweeping theory, 506 00:30:16,614 --> 00:30:19,651 Newton had redefined the cosmos. 507 00:30:19,651 --> 00:30:23,555 He had solved the mystery of what kept us on earth, 508 00:30:23,555 --> 00:30:27,458 what kept the Earth moving what set the stars in motion 509 00:30:27,458 --> 00:30:30,495 Even the church had to bow to the inevitable. 510 00:30:30,495 --> 00:30:32,230 The Ptolemaic system 511 00:30:32,664 --> 00:30:35,266 had surrendered to one word -- gravity. 512 00:30:39,170 --> 00:30:41,339 Barbour: he was the first person 513 00:30:44,375 --> 00:30:46,110 which manifestly worked. 514 00:30:46,544 --> 00:30:47,846 And the title of his great book, the "Principia" 515 00:30:47,846 --> 00:30:50,448 That real makes the point -- 516 00:30:50,448 --> 00:30:51,749 He described it as the mathematical principles 517 00:30:52,183 --> 00:30:53,484 of natural philosophy. 518 00:30:56,955 --> 00:30:59,557 Hawking: Newton's equations 519 00:30:59,557 --> 00:31:03,461 for gravity explained the elliptical orbits 520 00:31:03,895 --> 00:31:06,497 of the planets perfectly. 521 00:31:06,497 --> 00:31:09,100 Kepler and Copernicus were vindicated. 522 00:31:09,100 --> 00:31:11,269 According to Newton's theory 523 00:31:11,269 --> 00:31:13,872 the universe ran like clockwork forever. 524 00:31:14,305 --> 00:31:17,775 I think people were comforted by the thought 525 00:31:18,209 --> 00:31:20,378 that even though they grew old and died, 526 00:31:20,812 --> 00:31:24,282 the universe was eternal and unchanging. 527 00:31:31,222 --> 00:31:34,692 Narrator: with new telescopes based on Newton's design 528 00:31:35,126 --> 00:31:36,861 with a new vision of the sky based on his theories -- 529 00:31:36,861 --> 00:31:39,898 stargazing became popular. 530 00:31:40,331 --> 00:31:42,934 It was the age of gentleman astronomers. 531 00:31:42,934 --> 00:31:48,573 Man: I am William Brendan, The 7th Earl of Rosse, 532 00:31:48,573 --> 00:31:51,609 Great-great-grandson 533 00:31:51,609 --> 00:31:53,778 Of the 3rd Earl, who Was also another William 534 00:32:00,285 --> 00:32:02,453 His great achievement was the building 535 00:32:02,887 --> 00:32:05,490 of the great 6-foot telescope, 536 00:32:05,924 --> 00:32:09,827 Or Leviathan of Parsons Town , as it was called, 537 00:32:09,827 --> 00:32:11,562 That was the biggest and The most powerful telescope 538 00:32:11,996 --> 00:32:14,599 in the world up till the present century. 539 00:32:15,033 --> 00:32:16,768 Narrator: Brendan's Great-great-grandfather 540 00:32:20,238 --> 00:32:23,274 In the Marshy countryside outside Dublin. 541 00:32:23,274 --> 00:32:26,311 He made everything he needed himself, here. 542 00:32:26,744 --> 00:32:28,913 He made it in a foundry that he set up 543 00:32:28,913 --> 00:32:31,516 at the bottom of the moat, 544 00:32:31,516 --> 00:32:34,552 that was fueled by the turf from the local bogs, 545 00:32:34,552 --> 00:32:37,155 by making the most of all the resources he had. 546 00:32:37,155 --> 00:32:41,059 I think he wanted to see farther 547 00:32:41,059 --> 00:32:43,661 than anyone else had ever been able to see before. 548 00:32:43,661 --> 00:32:46,698 He invited great scientists and astronomers 549 00:32:47,131 --> 00:32:49,300 from all over the world 550 00:32:49,734 --> 00:32:51,903 to show them what he saw here at Birr, 551 00:32:52,337 --> 00:32:54,505 and that was amazing at the time, 552 00:32:54,939 --> 00:32:56,674 because many other of the early astronomers 553 00:32:56,674 --> 00:32:59,277 had guarded far more carefully, 554 00:32:59,277 --> 00:33:02,313 and he didn't want to do that. 555 00:33:02,313 --> 00:33:04,048 He wanted to share what he'd discovered with everyone. 556 00:33:09,687 --> 00:33:12,290 Narrator: today, a kindred spirit 557 00:33:12,290 --> 00:33:16,627 pays a call on the Earl of Rosse's telescope. 558 00:33:16,627 --> 00:33:19,230 Man: my name is Francisco Diego. 559 00:33:19,664 --> 00:33:23,568 I am involved in optical design In university college, London, 560 00:33:23,568 --> 00:33:28,773 And we are planning to build a new mirror for this telescope. 561 00:33:28,773 --> 00:33:30,942 Narrator: the antique Diego is restoring 562 00:33:30,942 --> 00:33:33,544 worked the same way as Newton's telescope. 563 00:33:33,544 --> 00:33:35,279 Images from space were concentrated 564 00:33:35,713 --> 00:33:37,882 on a concave mirror. 565 00:33:37,882 --> 00:33:40,918 In Newton's day, the mirror was 5 inches wide 566 00:33:41,352 --> 00:33:43,087 200 years later, the earl's 567 00:33:43,521 --> 00:33:46,557 was 6 feet in diameter. 568 00:33:46,557 --> 00:33:52,196 Diego: with telescopes Like Galileo or Newton, 569 00:33:52,196 --> 00:33:54,365 you could only see the solar system -- 570 00:33:54,799 --> 00:33:56,100 I mean the moon, the sun, the planets, 571 00:33:56,100 --> 00:33:58,269 and almost nothing else. 572 00:34:06,944 --> 00:34:11,716 Earl of Rosse: and you see here a plate 573 00:34:11,716 --> 00:34:15,620 of the 6-foot telescope with an observer 574 00:34:15,620 --> 00:34:20,391 here in position. 575 00:34:20,825 --> 00:34:23,861 Remembering, of course, that this is a reflecting telescope 576 00:34:23,861 --> 00:34:29,067 so the observers had to get into position at the top 577 00:34:29,500 --> 00:34:30,802 to look right down the length of the tube 578 00:34:31,235 --> 00:34:33,404 to see the image reflected 579 00:34:33,404 --> 00:34:36,007 in the giant 6-foot mirror at the bottom. 580 00:34:36,007 --> 00:34:37,742 I was browsing in your library, 581 00:34:37,742 --> 00:34:39,477 and found this book -- 582 00:34:39,911 --> 00:34:42,080 This is "Transactions Of the royal society" 583 00:34:42,080 --> 00:34:43,815 1850 or something like that. 584 00:34:43,815 --> 00:34:45,983 And there is the 3rd earl's 585 00:34:45,983 --> 00:34:48,152 Drawing of the whirlpool. 586 00:34:48,152 --> 00:34:50,321 - The whirlpool galaxy 587 00:34:50,321 --> 00:34:53,357 The first time the whirlpool galaxy was ever seen. 588 00:34:53,357 --> 00:34:57,261 Narrator: telescopes Like the earl of Rosse's 589 00:34:57,261 --> 00:34:59,864 gave new detail to distant wisps of light, 590 00:34:59,864 --> 00:35:02,033 assumed to be strange gaseous clouds 591 00:35:02,033 --> 00:35:04,960 on the fringes of our galaxy 592 00:35:04,960 --> 00:35:08,973 The realization that these were indeed other galaxies 593 00:35:08,973 --> 00:35:11,576 would only come after another conceptual breakthrough. 594 00:35:16,781 --> 00:35:19,817 The universe was once again about to be redefined -- 595 00:35:20,251 --> 00:35:21,986 now by light, 596 00:35:22,420 --> 00:35:25,890 born across time and the incomprehensible 597 00:35:26,324 --> 00:35:27,625 distances of space. 598 00:35:34,132 --> 00:35:37,602 Diego: spectroscopy is the analysis of light. 599 00:35:42,807 --> 00:35:46,711 The information that we get from starlight or from sunlight 600 00:35:46,711 --> 00:35:48,880 or from light in general is tremendous, is enormous. 601 00:35:56,687 --> 00:35:58,856 Narrator: it was a german physicist 602 00:35:59,290 --> 00:36:01,459 who discovered spectroscopy in the early 19th century -- 603 00:36:01,893 --> 00:36:05,363 Joseph von Frauenhofer. 604 00:36:05,796 --> 00:36:10,134 Diego: he was an optical manufacturer. 605 00:36:10,134 --> 00:36:14,038 He was working in a company which was building 606 00:36:14,038 --> 00:36:17,508 lenses for astronomers. 607 00:36:21,846 --> 00:36:24,882 He was very methodical. 608 00:36:24,882 --> 00:36:27,051 He used to write everything he did. 609 00:36:27,051 --> 00:36:30,087 And fortunately we have these texts 610 00:36:30,087 --> 00:36:32,256 of his own very words 611 00:36:36,594 --> 00:36:41,799 "In a shuttered room I allowed sunlight to pass 612 00:36:41,799 --> 00:36:43,534 through a narrow opening in the shutters 613 00:36:43,534 --> 00:36:47,438 onto a prism. 614 00:36:47,438 --> 00:36:51,776 I found with the telescope almost countless 615 00:36:52,210 --> 00:36:55,680 strong and weak vertical lines crossing the spectrum, 616 00:36:55,680 --> 00:36:58,716 which however are darker than the remaining part 617 00:36:59,150 --> 00:37:01,319 of the spectrum of the color image. 618 00:37:01,752 --> 00:37:07,391 Some seem to be nearly completely black." 619 00:37:07,825 --> 00:37:10,428 He couldn't explain the origin of these lines. 620 00:37:10,428 --> 00:37:12,163 He just saw that part of the spectrum was missing. 621 00:37:19,971 --> 00:37:22,139 Narrator: in the cryptic traces of its light, 622 00:37:22,573 --> 00:37:25,610 the universe reveals its true colors. 623 00:37:25,610 --> 00:37:29,513 We can see its chemical structure. 624 00:37:29,513 --> 00:37:32,116 Light is originated in atoms 625 00:37:32,550 --> 00:37:35,152 Light is originated 626 00:37:35,152 --> 00:37:39,924 every time that electrons in these atoms 627 00:37:39,924 --> 00:37:42,960 it's emitting or absorbing light at a particular frequency. 628 00:37:42,960 --> 00:37:46,864 So each chemical element has a particular way of behavior 629 00:37:46,864 --> 00:37:49,900 The electrons are jumping in particular places. 630 00:37:49,900 --> 00:37:52,069 So depending on these places 631 00:37:52,069 --> 00:37:56,407 is the position of the line in the spectrum. 632 00:37:56,841 --> 00:37:58,576 "Ah, this is hydrogen." 633 00:37:58,576 --> 00:38:00,608 But if the line appears here ?Ah this is not hydrogen, this is Sodium? 634 00:38:02,913 --> 00:38:05,516 So in the solar spectrum we have the finger prints 635 00:38:05,516 --> 00:38:07,251 of a lot of chemical elements 636 00:38:07,685 --> 00:38:10,288 that we can identify in our labs, 637 00:38:10,288 --> 00:38:14,625 because with the same equipment we take a spectrum off our lamp, 638 00:38:15,059 --> 00:38:17,662 say, for example, an arc of iron -- 639 00:38:18,016 --> 00:38:20,264 and we can produce the same lines in our labs 640 00:38:20,698 --> 00:38:22,867 And we match the lines from the sun 641 00:38:23,301 --> 00:38:26,771 with the lines from the lamp in our laboratory, 642 00:38:26,771 --> 00:38:28,072 and the match is perfect. 643 00:38:33,277 --> 00:38:36,747 Hawking: using spectroscopy it was found 644 00:38:36,747 --> 00:38:39,784 that the chemical content of our sun 645 00:38:39,784 --> 00:38:42,820 was identical to that of any star in the universe. 646 00:38:43,254 --> 00:38:47,591 Our sun, and our solar system itself, 647 00:38:47,591 --> 00:38:50,628 was just one of an infinite number of others. 648 00:38:50,628 --> 00:38:53,230 Perhaps we ourselves 649 00:38:53,230 --> 00:38:57,568 have no special place in the universe. 650 00:38:57,568 --> 00:39:03,207 Diego: the chemistry of stars is more or less the same 651 00:39:03,207 --> 00:39:05,810 As the chemistry of the sun, 652 00:39:05,810 --> 00:39:07,545 so the sun becomes a star or stars become suns. 653 00:39:11,882 --> 00:39:14,051 This is a big revolution. 654 00:39:14,051 --> 00:39:16,654 This is like a Copernican revolution, 655 00:39:16,654 --> 00:39:19,690 when you abandon the idea 656 00:39:19,690 --> 00:39:21,425 that the earth is the center of the universe, 657 00:39:21,859 --> 00:39:23,594 and you say, well, 658 00:39:24,028 --> 00:39:25,763 It's no longer the center of the universe 659 00:39:26,197 --> 00:39:27,932 no center at least of the solar system 660 00:39:28,366 --> 00:39:32,269 And that was a major revolution in science. 661 00:39:32,269 --> 00:39:35,740 Now we have another revolution in which we say, 662 00:39:35,740 --> 00:39:39,210 well, we are not so special about it, 663 00:39:39,210 --> 00:39:41,379 because our own bodies, our own chemistry, 664 00:39:41,379 --> 00:39:43,981 our blood, our bones, our skins -- 665 00:39:43,981 --> 00:39:48,753 they are made of hydrogen, nitrogen, oxygen, etcetera 666 00:39:48,753 --> 00:39:51,355 sodium, etcetera. 667 00:39:51,789 --> 00:39:53,090 And we find hydrogen and oxygen, etcetera, 668 00:39:53,524 --> 00:39:57,428 in nebulae, in stars, in the universe. 669 00:39:57,428 --> 00:39:59,597 So it is the same chemistry, 670 00:39:59,597 --> 00:40:01,766 so there is nothing special about it. 671 00:40:01,766 --> 00:40:06,103 Narrator: light, it turns out, is a messenger, 672 00:40:06,103 --> 00:40:09,573 as swift as it is informative. 673 00:40:09,573 --> 00:40:13,043 The news it bears is not just about chemistry. 674 00:40:13,043 --> 00:40:17,381 It also signals the motion of the universe itself. 675 00:40:17,381 --> 00:40:21,719 That discovery is owed in part to Christian Doppler. 676 00:40:21,719 --> 00:40:24,321 Diego: the doppler shift has been, perhaps, 677 00:40:24,755 --> 00:40:28,659 one of the tools in astrophysics, 678 00:40:29,093 --> 00:40:31,695 I would say in cosmology now 679 00:40:31,695 --> 00:40:35,166 because it is our speedometer, if you like. 680 00:40:35,166 --> 00:40:38,202 It is the meter that we use to measure the speed 681 00:40:38,636 --> 00:40:40,805 of almost everything in the universe. 682 00:40:45,576 --> 00:40:49,046 Narrator: Doppler suggested that, as an object moves, 683 00:40:49,480 --> 00:40:52,082 the light it emits will appear to be altered. 684 00:40:52,516 --> 00:40:55,553 We can't observe this in everyday life, 685 00:40:55,986 --> 00:40:59,890 because light moves too fast but we hear the same effect. 686 00:41:06,831 --> 00:41:08,566 Sound is also carried in waves. 687 00:41:08,999 --> 00:41:10,734 As it approaches, sound Is also carried in waves 688 00:41:10,734 --> 00:41:13,337 Its waves are squashed together. 689 00:41:13,337 --> 00:41:16,373 As it departs, the sound waves are stretched apart. 690 00:41:16,373 --> 00:41:20,711 The change in pitch is audible and known as the doppler shift 691 00:41:20,711 --> 00:41:22,880 [ Siren approaches ] 692 00:41:26,784 --> 00:41:28,085 [ Pitch of siren decreases ] 693 00:41:30,688 --> 00:41:32,857 By analyzing stars, 694 00:41:33,290 --> 00:41:35,025 scientists found the doppler shift at work 695 00:41:35,025 --> 00:41:37,628 in the light spectrum as well. 696 00:41:37,628 --> 00:41:39,797 If a light source moves toward us, 697 00:41:39,797 --> 00:41:42,399 The frauenhofer lines are shifted 698 00:41:42,399 --> 00:41:44,134 towards the blue end of the spectrum. 699 00:41:44,568 --> 00:41:45,870 If the light source is receding, 700 00:41:46,303 --> 00:41:47,605 the lines shift towards the red. 701 00:41:51,942 --> 00:41:54,545 Hawking: these extraordinary patterns in starlight 702 00:41:54,545 --> 00:41:59,316 brought the dawn of a new age for cosmology. 703 00:41:59,316 --> 00:42:01,919 It became possible to tell 704 00:42:02,353 --> 00:42:04,522 not only what the universe was made of, 705 00:42:04,522 --> 00:42:08,425 but also how it was moving. 706 00:42:08,425 --> 00:42:10,594 The breakthrough came 707 00:42:11,028 --> 00:42:14,932 by analyzing light from deep in the universe -- 708 00:42:14,932 --> 00:42:17,968 light seen through powerful new telescopes in America. 709 00:42:18,402 --> 00:42:20,571 They could reveal 710 00:42:20,928 --> 00:42:24,475 details of the universe never seen before. 711 00:42:24,475 --> 00:42:27,077 Jastrow: everybody knew what The Milky Way galaxy was -- 712 00:42:27,077 --> 00:42:28,812 A collection of billions of stars 713 00:42:28,812 --> 00:42:30,548 to which the sun belongs, 714 00:42:30,548 --> 00:42:32,716 but nobody knew 715 00:42:32,716 --> 00:42:34,451 What these little patches of nebulous material 716 00:42:34,451 --> 00:42:39,223 that looked like spirals and pancakes and so on were. 717 00:42:39,657 --> 00:42:41,392 And some people thought that the Milky Way galaxy 718 00:42:41,392 --> 00:42:43,127 was the whole universe, 719 00:42:44,428 --> 00:42:47,031 and these little spirals were wisps of gas in that universe. 720 00:42:57,875 --> 00:43:00,044 The most famous person that worked at Mount Wilson 721 00:43:00,044 --> 00:43:03,080 Was Edwin Hubble, 722 00:43:03,080 --> 00:43:05,683 who came here when he was quite young, actually, 723 00:43:05,683 --> 00:43:07,851 right after his service in world war I, 724 00:43:07,851 --> 00:43:10,020 and Hubble had the golden touch. 725 00:43:10,020 --> 00:43:13,057 He had a knack of picking the important problems. 726 00:43:13,490 --> 00:43:16,093 Narrator: no problem seemed more puzzling 727 00:43:16,527 --> 00:43:17,828 than the one posed by the Earl of Rosse 728 00:43:17,828 --> 00:43:20,431 and his contemporaries. 729 00:43:20,431 --> 00:43:22,166 What were those strange swirls they'd sighted? 730 00:43:22,600 --> 00:43:23,467 Hubble wanted to know. 731 00:43:39,950 --> 00:43:41,685 Jastrow: making use of the extraordinary clarity 732 00:43:41,685 --> 00:43:45,155 of the atmosphere over Mount Wilson, 733 00:43:45,589 --> 00:43:47,758 which is the best on the continent, 734 00:43:48,192 --> 00:43:50,361 he was able to distinguish individual stars 735 00:43:50,361 --> 00:43:53,397 in these little clouds of gas, these so-called nebulae, 736 00:43:53,397 --> 00:43:56,000 and that told him in itself 737 00:43:56,000 --> 00:43:59,470 that they were not wisps of gas in our galaxy, 738 00:43:59,470 --> 00:44:02,072 but galaxies in their own right, 739 00:44:02,072 --> 00:44:04,675 each one containing billions of stars, 740 00:44:04,675 --> 00:44:06,844 and that the universe, the true universe, 741 00:44:06,844 --> 00:44:08,579 was populated with countless numbers 742 00:44:08,579 --> 00:44:10,748 of island universes, 743 00:44:11,181 --> 00:44:12,916 each one like our Milky Way galaxy. 744 00:44:41,111 --> 00:44:44,581 The distances that he measured 745 00:44:44,581 --> 00:44:47,618 were absolutely stupefying to the astronomers of that time. 746 00:44:48,052 --> 00:44:50,220 He found that the Andromeda nebula, 747 00:44:50,220 --> 00:44:51,955 which is the closest galaxy to us like our own, 748 00:44:52,389 --> 00:44:54,558 was at least a million light years away, 749 00:44:54,992 --> 00:44:56,727 and a light year is 6 trillion miles -- 750 00:44:56,727 --> 00:44:58,896 a very, very great distance, 751 00:44:59,329 --> 00:45:02,366 far outside the edge of our own milky way galaxy. 752 00:45:02,366 --> 00:45:05,402 For the first time we knew how big the universe was 753 00:45:05,836 --> 00:45:08,005 with that discovery. 754 00:45:11,475 --> 00:45:14,511 Narrator: meanwhile, Doppler's theory came into play 755 00:45:14,511 --> 00:45:17,548 under the studied gaze of a colleague of Hubble's 756 00:45:17,548 --> 00:45:21,452 Vesto Slipher began to analyze light. 757 00:45:21,452 --> 00:45:24,054 Jastrow: all of the galaxies that he could see around him 758 00:45:24,488 --> 00:45:26,657 had red shifts, 759 00:45:26,657 --> 00:45:28,826 towards longer wavelengths. 760 00:45:28,826 --> 00:45:30,561 And that would mean, of course , that relative to us, 761 00:45:30,561 --> 00:45:33,163 they were moving away. 762 00:45:33,163 --> 00:45:37,935 When Slipher gave this report, everybody stood up and cheered 763 00:45:38,368 --> 00:45:40,537 They didn't know what it meant but they had a gut feeling 764 00:45:40,971 --> 00:45:41,839 that it was something cosmic in its significance. 765 00:45:47,044 --> 00:45:50,080 Narrator: that galaxies were speeding away from us 766 00:45:50,080 --> 00:45:53,117 was a discovery as striking as it was baffling. 767 00:45:53,117 --> 00:45:56,587 But unknown to Slipher and Hubble, 768 00:45:56,587 --> 00:46:01,792 an explanation was being formed an obscure german physicist. 769 00:46:01,792 --> 00:46:04,828 His new model of the universe would be no less radical 770 00:46:04,828 --> 00:46:07,865 than those of centuries past 771 00:46:07,865 --> 00:46:09,600 and among its predictions would be the revelation 772 00:46:10,033 --> 00:46:12,636 that the universe is rapidly expanding. 773 00:46:16,106 --> 00:46:19,143 All the more remarkable was that this insight came 774 00:46:19,143 --> 00:46:22,613 from a man now working as a patent clerk 775 00:46:22,613 --> 00:46:25,215 because he had shown so little academic promise 776 00:46:25,649 --> 00:46:26,950 His name -- Albert Einstein. 777 00:46:32,156 --> 00:46:34,324 He was forced to learn 778 00:46:34,324 --> 00:46:37,795 a lot of very complicated mathematics in order to do so. 779 00:46:37,795 --> 00:46:40,397 But in 1915 finally the theory was born. 780 00:46:40,397 --> 00:46:43,433 The theory was called General Relativity, 781 00:46:43,867 --> 00:46:48,205 And it differed from the theory of gravity 782 00:46:48,205 --> 00:46:51,241 that had held sway up until then for more than 200 years, 783 00:46:51,675 --> 00:46:54,278 which was newtonian gravity. 784 00:46:57,748 --> 00:47:01,218 In Newtonian gravity all objects in the universe attract each other directly. 785 00:47:01,218 --> 00:47:05,556 Einstein's theory of gravity is radically different, 786 00:47:05,556 --> 00:47:07,291 in fact, that the objects don't 787 00:47:07,291 --> 00:47:09,893 attract each other directly at all. 788 00:47:10,327 --> 00:47:13,363 One object makes dents or dimples or warps 789 00:47:13,363 --> 00:47:15,966 in the fabric of space-time itself, 790 00:47:15,966 --> 00:47:19,002 and the other object, as it moves by, 791 00:47:19,002 --> 00:47:22,039 is actually bent by the curvature of space-time 792 00:47:22,472 --> 00:47:25,075 by the fact that there's this dimple there. 793 00:47:25,075 --> 00:47:27,244 And it looks like it's being attracted to the first object, 794 00:47:27,678 --> 00:47:28,979 the object that's making the dimple, 795 00:47:29,413 --> 00:47:32,015 but, in fact, it's not direct. 796 00:47:32,015 --> 00:47:36,353 It's just reacting to The warpage of space-time 797 00:47:36,787 --> 00:47:38,956 So one thing to understand about general relativity 798 00:47:39,389 --> 00:47:41,376 is that you can't have a whole collection of matter 799 00:47:41,992 --> 00:47:44,161 say, of galaxies or stars, 800 00:47:44,595 --> 00:47:47,197 which are sitting in static configuration 801 00:47:47,197 --> 00:47:48,932 with respect to each other , and expect them to stay there. 802 00:47:49,216 --> 00:47:51,535 They won't. 803 00:47:51,535 --> 00:47:53,270 They are going to collapse in towards each other. 804 00:47:53,270 --> 00:47:55,439 So this means 805 00:47:55,439 --> 00:47:58,475 that you can't have 806 00:47:58,475 --> 00:48:01,945 A static model of the universe in general relativity. 807 00:48:02,379 --> 00:48:04,548 The model -- the universe either has to be expanding 808 00:48:04,548 --> 00:48:06,283 or it has to be contracting -- 809 00:48:06,283 --> 00:48:08,018 it has to be dynamical in some way. 810 00:48:08,018 --> 00:48:09,753 It can't possibly be static. 811 00:48:09,753 --> 00:48:11,922 Narrator: Einstein imagined that there must be 812 00:48:12,356 --> 00:48:14,524 some unknown force keeping the cosmos 813 00:48:14,958 --> 00:48:17,561 from collapsing in on itself. 814 00:48:17,561 --> 00:48:20,163 In fact, he had predicted that the universe is expanding 815 00:48:20,163 --> 00:48:22,332 Jastrow: the astronomers 816 00:48:22,766 --> 00:48:25,802 looked at Slipher's discovery of the motion of the galaxies, 817 00:48:25,802 --> 00:48:28,839 and the prediction that the universe expands, 818 00:48:29,273 --> 00:48:30,574 and they said, aha! These are two sides of one coin. 819 00:48:31,008 --> 00:48:32,309 They fit together. 820 00:48:32,743 --> 00:48:34,044 And Hubble again with that golden touch 821 00:48:34,044 --> 00:48:35,779 for working on the big problem 822 00:48:36,213 --> 00:48:38,382 turned his attention to this question, 823 00:48:38,382 --> 00:48:40,550 and he asked himself, how can I investigate it? 824 00:48:40,550 --> 00:48:43,153 And the way he did so was to start to measure 825 00:48:43,153 --> 00:48:44,888 the red shifts, as they are called -- 826 00:48:44,888 --> 00:48:46,623 the velocities with which 827 00:48:47,057 --> 00:48:50,961 these galaxies are moving away from us. 828 00:48:51,395 --> 00:48:54,865 Narrator: Hubble began the painstaking process 829 00:48:54,865 --> 00:48:56,600 of comparing the distance and redshifts 830 00:48:57,034 --> 00:48:59,202 of dozens of galaxies. 831 00:48:59,202 --> 00:49:02,239 The results were staggering. 832 00:49:02,673 --> 00:49:06,143 Jastrow: and he found something known today as Hubble's law, 833 00:49:06,143 --> 00:49:08,745 quite extraordinary, that the red shift 834 00:49:08,745 --> 00:49:10,480 or the velocity of recession from us 835 00:49:10,914 --> 00:49:14,384 is proportional to distance. 836 00:49:14,384 --> 00:49:16,553 If a galaxy at this distance 837 00:49:16,553 --> 00:49:18,722 is moving away from you at a certain speed, 838 00:49:19,156 --> 00:49:22,192 a galaxy twice as far away will be guaranteed 839 00:49:22,192 --> 00:49:23,060 to be moving away from you at twice the speed. 840 00:49:27,397 --> 00:49:29,566 Hubble actually changed 841 00:49:29,920 --> 00:49:32,169 the picture of the universe 842 00:49:32,169 --> 00:49:34,338 Because the ptolemaic picture was static, 843 00:49:34,338 --> 00:49:36,940 And Newton's picture 844 00:49:36,940 --> 00:49:39,109 of the universe was static 845 00:49:39,109 --> 00:49:42,145 but Hubble showed that the universe is dynamic 846 00:49:42,145 --> 00:49:42,579 Everything is moving away from everything else. 847 00:49:47,351 --> 00:49:49,953 Greek astronomers thought -- most of them, not all of them -- 848 00:49:49,953 --> 00:49:52,122 that the earth was the center of the universe 849 00:49:52,122 --> 00:49:54,725 Copernicus showed that that was not so, 850 00:49:55,158 --> 00:49:56,460 and thought the sun was the center of the universe. 851 00:49:56,893 --> 00:49:59,062 Other later astronomers showed 852 00:49:59,496 --> 00:50:00,797 no, the sun was not the center of the universe 853 00:50:00,797 --> 00:50:02,966 but many of them thought 854 00:50:03,400 --> 00:50:05,135 that the center of our galaxy was the center of the universe 855 00:50:05,135 --> 00:50:07,738 Hubble showed that there is no center. 856 00:50:07,738 --> 00:50:09,473 That was a tremendous scientific, theological, 857 00:50:09,906 --> 00:50:12,509 and philosophical accomplishment. 858 00:50:12,509 --> 00:50:15,112 He showed that the universe as far as the telescope can see 859 00:50:15,112 --> 00:50:17,714 is populated with countless numbers of island universes, 860 00:50:18,148 --> 00:50:19,449 and there is no difference whatsoever. 861 00:50:19,449 --> 00:50:21,618 There is no center. 862 00:50:22,052 --> 00:50:24,654 The second implication in his finding was -- 863 00:50:25,088 --> 00:50:27,691 well, to explain it, 864 00:50:27,691 --> 00:50:30,293 imagine that the picture of the expanding galaxies 865 00:50:30,293 --> 00:50:31,595 moving away from us and one another 866 00:50:31,595 --> 00:50:32,896 Is a movie strip. 867 00:50:32,896 --> 00:50:35,499 Now run that in reverse. 868 00:50:35,499 --> 00:50:36,800 And all the galaxies going backward in time 869 00:50:37,234 --> 00:50:39,403 come closer and closer together. 870 00:50:39,403 --> 00:50:41,571 And finally they all meet together at one point 871 00:50:42,005 --> 00:50:43,306 Speaking loosely, because there is no one point, 872 00:50:43,740 --> 00:50:46,343 there is no center in the universe. 873 00:50:46,343 --> 00:50:48,078 They all come together in an infinitely dense 874 00:50:48,078 --> 00:50:50,680 and yet infinitely extended moment 875 00:50:50,680 --> 00:50:52,416 And beyond that, of infinite density, 876 00:50:52,416 --> 00:50:54,584 one cannot go. 877 00:50:54,584 --> 00:50:56,319 So that moment marks the beginning 878 00:50:56,319 --> 00:50:58,055 or the birth of the universe 879 00:50:58,488 --> 00:50:59,790 And all of the things that we see around us -- 880 00:50:59,790 --> 00:51:01,958 every star, every planet, 881 00:51:01,958 --> 00:51:04,127 every living thing on the earth and in the cosmos 882 00:51:04,127 --> 00:51:05,429 owes its genesis to that moment 883 00:51:05,862 --> 00:51:07,597 You can call it the big bang 884 00:51:07,597 --> 00:51:09,332 but you can also call it with accuracy 885 00:51:09,332 --> 00:51:11,068 The moment of creation. 886 00:51:11,501 --> 00:51:14,971 Narrator: today, our expanding vision 887 00:51:14,971 --> 00:51:17,574 is keeping pace with an expanding universe 888 00:51:17,574 --> 00:51:20,177 There are new revelations 889 00:51:20,177 --> 00:51:26,683 of the big bang, of dark matter, of a strange breach of space 890 00:51:29,286 --> 00:51:31,888 What are called black holes 891 00:51:31,888 --> 00:51:35,358 A black hole is a gaping void in space 892 00:51:35,358 --> 00:51:40,997 that sucks in and devours anything that gets too near. 893 00:51:40,997 --> 00:51:43,600 It becomes compact, massive, and therefore able to -- 894 00:51:43,600 --> 00:51:46,203 if it encounters something else -- 895 00:51:46,636 --> 00:51:47,938 able to eat some more matter 896 00:51:47,938 --> 00:51:49,673 It becomes the eater of all things. 897 00:51:53,577 --> 00:51:55,312 Narrator: cosmologists are now 898 00:51:55,312 --> 00:51:56,613 exploring a universe their predecessors 899 00:51:57,047 --> 00:51:58,782 would hardly recognize. 900 00:51:59,216 --> 00:52:00,951 Hawking: it seems that the kind of matter 901 00:52:00,951 --> 00:52:03,120 of which we are made 902 00:52:03,120 --> 00:52:04,855 constitutes only a small fraction 903 00:52:04,855 --> 00:52:07,457 of the universe. 904 00:52:07,457 --> 00:52:10,927 Over 90% is something we cannot even see -- 905 00:52:11,361 --> 00:52:12,662 dark matter. 906 00:52:13,096 --> 00:52:14,397 It sort of puts one in -- 907 00:52:14,831 --> 00:52:16,566 as a human being -- 908 00:52:16,566 --> 00:52:18,735 into some perspective, 909 00:52:19,169 --> 00:52:21,338 that the earth is not 910 00:52:21,771 --> 00:52:23,507 the center of the solar system 911 00:52:23,507 --> 00:52:25,675 we are not even made of particularly 912 00:52:25,675 --> 00:52:27,410 cmmon matter that's around, 913 00:52:27,410 --> 00:52:30,013 because most of it's dark matter. 914 00:52:30,447 --> 00:52:32,616 Narrator: gradually, the heavens are yielding 915 00:52:32,616 --> 00:52:34,784 their secrets to us. 916 00:52:35,218 --> 00:52:36,953 These photographs are from the orbiting telescope 917 00:52:36,953 --> 00:52:38,688 named after Hubble. 918 00:52:43,026 --> 00:52:45,629 Hawking: from sitting at the center of the universe, 919 00:52:45,984 --> 00:52:49,533 we now find ourselves orbiting an average-sized sun, 920 00:52:49,533 --> 00:52:51,701 which is just one of millions of stars 921 00:52:51,701 --> 00:52:55,172 in our own Milky Way galaxy. 922 00:52:55,172 --> 00:52:57,774 And our galaxy itself 923 00:52:57,774 --> 00:53:00,377 is just one of billions of galaxies 924 00:53:00,810 --> 00:53:04,281 in a universe that is infinite and expanding. 925 00:53:04,281 --> 00:53:08,618 But this is far from the end of a long history of inquiry 926 00:53:08,618 --> 00:53:12,088 Huge questions remain to be answered 927 00:53:12,522 --> 00:53:14,691 before we can hope to have 928 00:53:15,125 --> 00:53:17,294 a complete picture of the universe we live in 929 00:53:23,800 --> 00:53:26,836 To learn more about Stephen Hawking's Universe, 930 00:53:26,836 --> 00:53:29,439 visit pbs online at the Internet address on your screen. 931 00:53:47,657 --> 00:53:49,826 --Captions by vitac-- burbank, Pittsburgh, tampa, and washington, d.c. 932 00:54:30,600 --> 00:54:32,769 ?Stephen Hawking's Universe" was made possible 933 00:54:33,203 --> 00:54:35,372 By Alfred P. Sloan foundation, To enhance public understanding 934 00:54:35,372 --> 00:54:37,974 Of the role of science and technology, 935 00:54:37,974 --> 00:54:41,444 The Arthur Vining Davis foundations, 936 00:54:41,444 --> 00:54:43,613 The corporation for public broadcasting, 937 00:54:44,047 --> 00:54:46,216 And viewers like you. 938 00:54:46,650 --> 00:54:49,252 Corporate funding is provided by Amgen, 939 00:54:49,686 --> 00:54:51,855 Unlocking the secrets of Life through biotechnology. 940 00:54:52,289 --> 00:54:54,024 At Amgen, we produce medicines 941 00:54:54,024 --> 00:54:55,759 That improve people's lives today 942 00:54:55,759 --> 00:54:57,494 And bring hope for tomorrow. 943 00:55:36,099 --> 00:55:38,268 "Stephen Hawking's Universe" is made possible 944 00:55:38,268 --> 00:55:40,437 By Alfred P. Sloan foundation To enhance public understanding 945 00:55:40,870 --> 00:55:42,605 Of the role of science and technology, 946 00:55:43,039 --> 00:55:47,377 The Arthur Vining Davis foundations, 947 00:55:47,377 --> 00:55:49,979 The corporation for public broadcasting, 948 00:55:50,413 --> 00:55:52,582 And viewers like you. 949 00:55:53,016 --> 00:55:55,618 Corporate funding is provided by Amgen, 950 00:55:55,618 --> 00:55:57,354 Unlocking the secrets of Life through biotechnology. 951 00:55:57,354 --> 00:55:59,089 At Amgen, we produce medicines 952 00:55:59,522 --> 00:56:01,257 That improve people's lives today 953 00:56:01,257 --> 00:56:02,992 And bring hope for tomorrow.