1 00:00:02,760 --> 00:00:07,200 The practice of science has shaped the modern era. 2 00:00:07,200 --> 00:00:10,080 But how are discoveries made? 3 00:00:10,080 --> 00:00:12,920 And how does science progress? 4 00:00:12,920 --> 00:00:16,800 Three British scientists, world leaders in their fields, 5 00:00:16,800 --> 00:00:21,040 have changed our understanding of our universe, our planet 6 00:00:21,040 --> 00:00:22,480 and ourselves. 7 00:00:22,480 --> 00:00:26,920 A physicist, whose mysterious radio signals from space 8 00:00:26,920 --> 00:00:28,560 rewrote astronomy. 9 00:00:28,560 --> 00:00:31,360 She actually recognised that there was something happening. 10 00:00:31,360 --> 00:00:36,880 I suspect that perhaps only one in 100 people would have spotted it. 11 00:00:36,880 --> 00:00:40,800 A chemist, whose radical theory about our planet 12 00:00:40,800 --> 00:00:42,800 divides the scientific world. 13 00:00:42,800 --> 00:00:46,000 He's one of the greatest thinkers of the current age, 14 00:00:46,000 --> 00:00:48,680 and destined to go down in history. 15 00:00:48,680 --> 00:00:54,520 And a biologist, who discovered the secret of life in a sea urchin. 16 00:00:54,520 --> 00:00:57,600 Your fundamental discoveries have profoundly increased 17 00:00:57,600 --> 00:01:02,560 our understanding of how the cell cycle is controlled. 18 00:01:02,560 --> 00:01:06,520 Their stories tell us about the nature of scientific inquiry 19 00:01:06,520 --> 00:01:08,200 in the modern world. 20 00:01:08,200 --> 00:01:11,040 About how scientific breakthroughs are made. 21 00:01:11,040 --> 00:01:15,440 And about the workings of the scientific brain. 22 00:01:32,760 --> 00:01:37,200 Scientists should never claim that something is absolutely true. 23 00:01:37,200 --> 00:01:41,280 You should never claim perfect or total or 100%, 24 00:01:41,280 --> 00:01:44,400 because you never, ever get there. 25 00:01:45,960 --> 00:01:51,440 If we assume we have arrived, we stop searching. 26 00:01:51,440 --> 00:01:53,640 We stop developing. 27 00:01:55,120 --> 00:01:59,600 In 1967, a PhD student called Jocelyn Bell 28 00:01:59,600 --> 00:02:02,400 noticed something that shouldn't happen. 29 00:02:05,240 --> 00:02:10,640 Strange, regular flashes of energy emanating from deep space. 30 00:02:10,640 --> 00:02:14,760 She had discovered completely new types of stars 31 00:02:14,760 --> 00:02:17,920 that came to be known as pulsars. 32 00:02:17,920 --> 00:02:20,280 You were responsible for spotting 33 00:02:20,280 --> 00:02:23,360 the very first pulsar personally, I think. 34 00:02:23,360 --> 00:02:26,600 Jocelyn Bell's discovery fundamentally changed 35 00:02:26,600 --> 00:02:29,720 science's understanding of the universe. 36 00:02:29,720 --> 00:02:33,760 All of a sudden, people went from thinking about the universe 37 00:02:33,760 --> 00:02:36,040 been relatively dull and boring, 38 00:02:36,040 --> 00:02:37,960 to suddenly the universe is full 39 00:02:37,960 --> 00:02:40,600 of these things flickering and flashing around. 40 00:02:40,600 --> 00:02:43,240 It was really amazing and very exciting. 41 00:02:45,080 --> 00:02:48,920 'The girl who started all the fuss about the pulsars, Jocelyn Bell, 42 00:02:48,920 --> 00:02:51,200 'was a research student at Cambridge.' 43 00:02:51,200 --> 00:02:53,360 Pulsars provided the first evidence 44 00:02:53,360 --> 00:02:56,640 that Einstein's theory of gravity was right, 45 00:02:56,640 --> 00:03:00,640 and resulted in the winning of a Nobel Prize. 46 00:03:00,640 --> 00:03:02,560 But according to their finder, 47 00:03:02,560 --> 00:03:06,520 their discovery tells us about the nature of science itself. 48 00:03:10,240 --> 00:03:12,640 Science always doesn't go forwards. 49 00:03:12,640 --> 00:03:15,160 It's a bit like doing a Rubik's Cube. 50 00:03:15,160 --> 00:03:18,160 You sometimes have to make more of a mess with a Rubik's Cube 51 00:03:18,160 --> 00:03:20,200 before you can get it to go right. 52 00:03:20,200 --> 00:03:23,440 You build up this picture of what there is. 53 00:03:23,440 --> 00:03:28,240 You believe it to be true and you work with a picture and refine it. 54 00:03:28,240 --> 00:03:31,400 But sometimes you have to abandon the picture. 55 00:03:31,400 --> 00:03:35,040 Sometimes you discover that the picture you thought you had, 56 00:03:35,040 --> 00:03:39,080 that everybody thought we had, actually turns out to be wrong. 57 00:03:40,240 --> 00:03:43,160 Way back in the Middle Ages, 58 00:03:43,160 --> 00:03:47,240 they thought that planets went round the Sun in circles, perfect circles. 59 00:03:47,240 --> 00:03:49,960 They had to be perfect, they were heavenly bodies. 60 00:03:49,960 --> 00:03:54,760 And then they got better telescopes, better data and they recognised that 61 00:03:54,760 --> 00:03:57,800 the planets weren't where they expected them to be. 62 00:03:57,800 --> 00:04:00,040 They weren't in the right place. 63 00:04:00,040 --> 00:04:02,960 But they were reluctant to relinquish the circles 64 00:04:02,960 --> 00:04:08,120 so they invented epicycles, little circles on the rim of the big circle. 65 00:04:08,120 --> 00:04:11,200 Like a roundabout of roundabouts. 66 00:04:11,200 --> 00:04:15,080 And they could explain what they observed like that. 67 00:04:15,080 --> 00:04:17,920 Then they got better telescopes and better data and found that they had 68 00:04:17,920 --> 00:04:22,560 to add more epicycles and it got messier and messier and messier. 69 00:04:22,560 --> 00:04:26,640 And then one of the key astronomers of the time, Johannes Kepler, 70 00:04:26,640 --> 00:04:30,920 said maybe it's not circles, or circles plus epicycles, 71 00:04:30,920 --> 00:04:34,560 or circles plus epicycles with epicycles on them, 72 00:04:34,560 --> 00:04:37,960 maybe it's slightly squashed circles, ellipses. 73 00:04:37,960 --> 00:04:40,800 And that cleared the air wonderfully, 74 00:04:40,800 --> 00:04:44,880 and suddenly it was clear and simple again. 75 00:04:50,760 --> 00:04:52,640 Constant questioning of assumptions 76 00:04:52,640 --> 00:04:57,960 and probing of ideas has defined Professor Bell Burnell's career. 77 00:04:57,960 --> 00:05:01,320 It is this philosophy that resulted in her becoming one 78 00:05:01,320 --> 00:05:03,400 of the world's leading scientists. 79 00:05:03,400 --> 00:05:05,800 An astrophysicist who believes her discipline 80 00:05:05,800 --> 00:05:09,200 reveals the essence of who we are. 81 00:05:09,200 --> 00:05:14,960 The kind of chemical elements that you find inside the human body, 82 00:05:14,960 --> 00:05:18,240 hydrogen and oxygen in the water, 83 00:05:18,240 --> 00:05:23,720 carbon in our tissue and calcium in our bones, iron in our bloodstream, 84 00:05:23,720 --> 00:05:28,000 they've come from the Earth as that's where the plants got them from. 85 00:05:28,000 --> 00:05:32,640 The Earth and the Sun, because they formed at much the same time, 86 00:05:32,640 --> 00:05:37,680 got these chemical elements from previous exploding stars. 87 00:05:41,200 --> 00:05:45,840 The material goes through a stellar cycle, explodes, gets incorporated 88 00:05:45,840 --> 00:05:49,520 in the Sun and the Earth and into us. 89 00:05:49,520 --> 00:05:53,320 When we die, those atoms will get returned to the Earth. 90 00:05:55,240 --> 00:06:01,280 We are intimately and ultimately children of the stars. 91 00:06:01,280 --> 00:06:03,400 We're made of star stuff. 92 00:06:04,960 --> 00:06:10,600 So when we look at the night sky, we're seeing the kind of environment 93 00:06:10,600 --> 00:06:14,960 that we came from, that the atoms of which we're made came from. 94 00:06:14,960 --> 00:06:18,360 The roots of our being, if you like. 95 00:06:18,360 --> 00:06:23,000 And that's why I find astronomy so important and so fascinating. 96 00:06:27,280 --> 00:06:31,160 Jocelyn, how did you first become interested in the stars? 97 00:06:31,160 --> 00:06:33,760 I've been interested as long as I can remember, Sue. 98 00:06:39,480 --> 00:06:43,480 Dad had a subscription to the Linen Hall Library in Belfast 99 00:06:43,480 --> 00:06:46,400 and brought home all sorts of books. 100 00:06:46,400 --> 00:06:49,560 But the ones that really caught my attention 101 00:06:49,560 --> 00:06:52,280 were two or three books about astronomy. 102 00:06:52,280 --> 00:06:57,120 Fred Hoyle's Frontiers Of Astronomy and a book by Dennis Sciama. 103 00:06:59,320 --> 00:07:03,240 Astronomical distances have the air of a conjuring trick. 104 00:07:03,240 --> 00:07:07,680 The vastness of cosmic dimensions fills us with astonishment. 105 00:07:07,680 --> 00:07:09,560 Yet like a conjuring trick, 106 00:07:09,560 --> 00:07:14,120 it all looks very obvious when we see how it's done. 107 00:07:14,120 --> 00:07:18,560 It was reading those books that made me realise 108 00:07:18,560 --> 00:07:22,560 what an exciting and interesting subject astronomy was. 109 00:07:22,560 --> 00:07:26,400 I find it fascinating that with a limited number 110 00:07:26,400 --> 00:07:31,880 of snapshots or observations of the sky, we can deduce so much. 111 00:07:31,880 --> 00:07:35,200 Not just the evolution of stars and galaxies, but actually 112 00:07:35,200 --> 00:07:37,520 the evolution of the whole universe. 113 00:07:37,520 --> 00:07:40,800 How it began, and how it'll end. 114 00:07:40,800 --> 00:07:44,320 Nowhere else in science can you get this big picture. 115 00:07:44,320 --> 00:07:46,480 It's unique to astronomy. 116 00:07:50,840 --> 00:07:53,000 Today, a new moon is in the sky. 117 00:07:53,000 --> 00:07:57,720 A 23-inch metal sphere placed in orbit by a Russian rocket. 118 00:07:57,720 --> 00:08:00,000 The launch of the Sputnik satellite 119 00:08:00,000 --> 00:08:03,320 was a real shock in Britain, and in the USA, 120 00:08:03,320 --> 00:08:05,720 because both Britain and the US 121 00:08:05,720 --> 00:08:08,960 believed they were in advance of the Soviets technically, 122 00:08:08,960 --> 00:08:13,280 and then the Soviets go and launch a satellite, which we couldn't do. 123 00:08:13,280 --> 00:08:15,560 You are hearing the actual signals 124 00:08:15,560 --> 00:08:18,760 transmitted by the Earth-circling satellite. One of the great 125 00:08:18,760 --> 00:08:20,640 scientific feats of the age. 126 00:08:20,640 --> 00:08:23,880 So clearly there was some hard thought and head-scratching, 127 00:08:23,880 --> 00:08:28,560 and as a consequence, there was suddenly a great emphasis on science. 128 00:08:28,560 --> 00:08:32,560 Science was very well-regarded and any kids who could do science 129 00:08:32,560 --> 00:08:35,440 were encouraged to go and do science. 130 00:08:35,440 --> 00:08:39,120 And I was part of that movement. 131 00:08:39,120 --> 00:08:44,200 My father would get us up to see Sputniks go by and he'd explain 132 00:08:44,200 --> 00:08:49,280 to us the difference between a satellite and, say, a shooting star. 133 00:08:49,280 --> 00:08:52,960 We named one of our cats after one of the satellites, in fact, Vostok. 134 00:08:52,960 --> 00:08:56,560 So it was very much embedded in the family. 135 00:08:59,360 --> 00:09:03,880 With the space race, science had acquired an air of glamour, 136 00:09:03,880 --> 00:09:07,720 inspiring a new generation of scientists. 137 00:09:10,000 --> 00:09:13,640 I went away to boarding school at age 13. 138 00:09:13,640 --> 00:09:18,720 The physics teacher that I had, Mr Tillett, was a super teacher. 139 00:09:18,720 --> 00:09:22,960 One of the things I remember him teaching us is that 140 00:09:22,960 --> 00:09:25,440 once you got a grip on physics, 141 00:09:25,440 --> 00:09:30,880 you only need to learn relatively few facts and then you can build on that. 142 00:09:30,880 --> 00:09:33,240 You can develop a long, long way 143 00:09:33,240 --> 00:09:36,760 from relatively few bits of information in the first place. 144 00:09:36,760 --> 00:09:39,000 And that economy appealed to me. 145 00:09:42,680 --> 00:09:46,840 I could well have had a physics teacher who took the view 146 00:09:46,840 --> 00:09:50,000 that girls couldn't do physics, what's-the-point-of-trying? 147 00:09:50,000 --> 00:09:53,680 I'm not sure where I'd have gone then, what I'd have done, 148 00:09:53,680 --> 00:09:56,120 but Mr Tillett was quite the opposite. 149 00:09:56,120 --> 00:10:00,560 But at university, Bell encountered a less enlightened attitude. 150 00:10:05,440 --> 00:10:10,000 I went to Glasgow, and I was the only woman doing physics. 151 00:10:10,000 --> 00:10:13,560 Every time I entered the lecture theatre, as was the tradition, 152 00:10:13,560 --> 00:10:17,560 the guys whistled, stamped, cat-called, banged their desks. 153 00:10:17,560 --> 00:10:21,280 And I had to learn not to blush 154 00:10:21,280 --> 00:10:25,960 because if you blush, they do it more noisily. 155 00:10:25,960 --> 00:10:31,080 It also had an isolating effect, there was a them and me. 156 00:10:31,080 --> 00:10:34,440 I was rather on my own the whole time. 157 00:10:39,960 --> 00:10:42,000 Since then, Professor Bell Burnell 158 00:10:42,000 --> 00:10:44,680 has campaigned to encourage women into science. 159 00:10:44,680 --> 00:10:49,280 Not for the benefit of women, but for the benefit of science. 160 00:10:49,280 --> 00:10:52,800 One of the things women bring to a research project, 161 00:10:52,800 --> 00:10:57,200 or indeed any project, is they come from a different place. 162 00:10:57,200 --> 00:10:58,880 They've got a different background. 163 00:10:58,880 --> 00:11:02,040 Science has been named, 164 00:11:02,040 --> 00:11:03,640 developed, interpreted, 165 00:11:03,640 --> 00:11:08,280 by white males for decades. 166 00:11:08,280 --> 00:11:12,360 Women view the conventional wisdom from a slightly different angle, 167 00:11:12,360 --> 00:11:16,360 and that sometimes means they can clearly point to flaws 168 00:11:16,360 --> 00:11:19,680 in the logic, gaps in the argument. 169 00:11:19,680 --> 00:11:23,200 They can give a different perspective of what science is. 170 00:11:29,960 --> 00:11:33,480 For centuries, man has used his eyes to look at the stars. 171 00:11:33,480 --> 00:11:39,200 But now he's found a new method of observing the universe. 172 00:11:39,200 --> 00:11:44,360 The early '60s were very exciting times in astronomy, 173 00:11:44,360 --> 00:11:46,600 particularly radio astronomy. 174 00:11:46,600 --> 00:11:53,080 Radio astronomy was perhaps 10, 15 years old, coming into its prime, 175 00:11:53,080 --> 00:11:56,600 discovering things right, left and centre. It was all going on. 176 00:11:56,600 --> 00:11:58,360 It was fantastic. 177 00:12:00,000 --> 00:12:03,880 Cambridge University, where Jocelyn Bell had started her PhD, 178 00:12:03,880 --> 00:12:07,320 was leading the world in modern radio astronomy. 179 00:12:07,320 --> 00:12:11,520 It's almost as if astronomers and indeed physicists were 180 00:12:11,520 --> 00:12:16,240 in the position of Columbus at the time he discovered a new continent. 181 00:12:16,240 --> 00:12:19,280 This is the way we feel at the present time. 182 00:12:19,280 --> 00:12:21,360 There were a lot of big names around. 183 00:12:21,360 --> 00:12:25,800 Stephen Hawking and Dennis Sciama and Fred Hoyle, and so on. 184 00:12:25,800 --> 00:12:28,400 So there were a lot of very, very brilliant people there. 185 00:12:30,680 --> 00:12:33,600 Jocelyn Bell had found her spiritual home. 186 00:12:33,600 --> 00:12:37,760 It was here that glamorous Russian satellites, 187 00:12:37,760 --> 00:12:39,480 Mr Tillett's inspirational teaching 188 00:12:39,480 --> 00:12:44,640 and Glasgow University's trial by ordeal would start to bear fruit. 189 00:12:46,840 --> 00:12:51,520 This is the Mullard Radio Astronomy Observatory. 190 00:12:51,520 --> 00:12:54,240 A branch of the Cavendish Laboratory of Cambridge University. 191 00:12:54,240 --> 00:12:59,200 And here we can see Dr Tony Hewish who will tell us more about it. 192 00:12:59,200 --> 00:13:02,560 We were looking far beyond optical telescopes. 193 00:13:02,560 --> 00:13:04,800 I mean, you felt very privileged, actually. 194 00:13:04,800 --> 00:13:08,680 It was like opening a new window onto the universe and you 195 00:13:08,680 --> 00:13:12,760 were the first people to have a look out through and see what was there. 196 00:13:12,760 --> 00:13:17,000 And to realise that you were probing back in time. 197 00:13:17,000 --> 00:13:20,720 Distance and time go together the further off you can see something, 198 00:13:20,720 --> 00:13:25,280 the earlier in the history of the universe it actually happens to be. 199 00:13:25,280 --> 00:13:30,200 Here we were looking back over the history of the universe, in a sense. 200 00:13:30,200 --> 00:13:34,280 Discovering things that you could only discover that way. 201 00:13:34,280 --> 00:13:38,200 One of the pioneers of radio astronomy is Martin Ryle. 202 00:13:39,960 --> 00:13:43,120 With optical telescopes, one is limited to a range 203 00:13:43,120 --> 00:13:44,960 of observation about here. 204 00:13:44,960 --> 00:13:47,720 With radio telescopes, one can however detect galaxies 205 00:13:47,720 --> 00:13:51,920 at greater distances and with a new large radio telescope at Cambridge, 206 00:13:51,920 --> 00:13:54,680 we think we're being able to detect galaxies 207 00:13:54,680 --> 00:13:57,120 right out to this region here. 208 00:13:57,120 --> 00:14:02,280 The Cambridge Radio Astronomy Group had an interest in distant objects 209 00:14:02,280 --> 00:14:05,760 because they were interested in general in how the universe 210 00:14:05,760 --> 00:14:09,520 had evolved and therefore you want to try to see things 211 00:14:09,520 --> 00:14:12,000 at early stages of the universe. 212 00:14:12,000 --> 00:14:16,080 It was just so exciting, so stimulating. 213 00:14:16,080 --> 00:14:21,160 The big question was - did the universe have a finite origin 214 00:14:21,160 --> 00:14:25,560 in time, did it suddenly start, or was there no beginning? 215 00:14:25,560 --> 00:14:27,680 Because one of the nice theories, 216 00:14:27,680 --> 00:14:31,120 Fred Hoyle and others, the so-called steady state cosmology, 217 00:14:31,120 --> 00:14:36,040 was that overall, the population of the universe with regard to stars 218 00:14:36,040 --> 00:14:38,560 and galaxies was roughly constant 219 00:14:38,560 --> 00:14:42,120 and that's why it was called the steady state universe. 220 00:14:42,120 --> 00:14:44,960 Well, it turned out to be quite untrue. 221 00:14:44,960 --> 00:14:48,560 Now, the observations we were making over the past two years, 222 00:14:48,560 --> 00:14:50,440 seemed to show quite conclusively 223 00:14:50,440 --> 00:14:54,680 that the steady state theory of the universe can't be correct. 224 00:14:54,680 --> 00:14:58,320 The results imply that the universe is changing with time. 225 00:15:02,200 --> 00:15:05,680 One was looking back at an earlier phase of the universe 226 00:15:05,680 --> 00:15:09,880 and you can look back and say, well, was the universe the same 227 00:15:09,880 --> 00:15:13,320 as the present day universe we see above us now? 228 00:15:13,320 --> 00:15:15,200 And the answer to that was no. 229 00:15:15,200 --> 00:15:19,880 The universe is evolving and that immediately rules out 230 00:15:19,880 --> 00:15:23,960 the steady state and points in favour 231 00:15:23,960 --> 00:15:27,000 of a sudden creation. 232 00:15:27,000 --> 00:15:32,080 Each time you do research in science, you're tackling a question or two 233 00:15:32,080 --> 00:15:35,280 and you find that you've got some more questions 234 00:15:35,280 --> 00:15:37,160 uncovered by your research. 235 00:15:37,160 --> 00:15:40,720 So it's like having circles and each time you reached the rim 236 00:15:40,720 --> 00:15:44,440 of the circle, you realise there's more questions and another circle 237 00:15:44,440 --> 00:15:48,040 outside it, and you go to the rim of that circle, 238 00:15:48,040 --> 00:15:50,360 and you realise there's more outside it. 239 00:15:50,360 --> 00:15:54,200 But you're hooked, and you just keep going. 240 00:15:54,200 --> 00:15:56,840 As long as the funding, as long as life will allow you, 241 00:15:56,840 --> 00:16:01,080 you just keep pursuing question after question after question. 242 00:16:02,800 --> 00:16:07,320 Radio astronomy was prompting a wholesale re-evaluation 243 00:16:07,320 --> 00:16:11,440 of what was held to be true about the nature of the universe. 244 00:16:11,440 --> 00:16:14,360 A perfect field of study for a young scientist 245 00:16:14,360 --> 00:16:16,760 with a passion for the unknown. 246 00:16:16,760 --> 00:16:20,600 I was given almost complete choice of PhD topic. 247 00:16:20,600 --> 00:16:24,680 They ruled out one as being not suitable for a woman, 248 00:16:24,680 --> 00:16:28,640 because it involved a lot of heavy manual labour. 249 00:16:28,640 --> 00:16:32,160 But I was given free range of the rest, 250 00:16:32,160 --> 00:16:34,480 and Tony Hewish had this project 251 00:16:34,480 --> 00:16:36,040 to identify quasars. 252 00:16:38,120 --> 00:16:41,560 We discovered in 1964 that quasars, 253 00:16:41,560 --> 00:16:46,200 particularly energetic radio galaxies that have compact nuclei, 254 00:16:46,200 --> 00:16:52,060 twinkled in a way that ordinary radio galaxies did not. 255 00:16:52,060 --> 00:16:56,420 So here was a way immediately to sort out 256 00:16:56,420 --> 00:17:01,340 which radio galaxies in your survey were the interesting ones. 257 00:17:01,340 --> 00:17:04,060 The project was to find more quasars 258 00:17:04,060 --> 00:17:07,900 and to try and understand better what they were. 259 00:17:07,900 --> 00:17:11,580 But first, we had to build the radio telescope and actually, 260 00:17:11,580 --> 00:17:15,660 I spent two of my three years constructing a radio telescope. 261 00:17:15,660 --> 00:17:17,460 Professor Ryle, I think 262 00:17:17,460 --> 00:17:22,500 this will contradict most people's idea of a radio telescope. 263 00:17:22,500 --> 00:17:24,620 I think the popular image is one of a big dish. 264 00:17:24,620 --> 00:17:26,220 Yes. Well, for some problems 265 00:17:26,220 --> 00:17:30,020 the big dish is the best solution, but for this particular problem 266 00:17:30,020 --> 00:17:33,300 of detecting the extremely faint radio sources, we have something 267 00:17:33,300 --> 00:17:35,340 which we think is better. 268 00:17:39,100 --> 00:17:44,700 The telescope covered four and a half acres. 269 00:17:44,700 --> 00:17:50,340 To put that in some sort of context, that's 57 tennis courts, and it had 270 00:17:50,340 --> 00:17:56,060 120 miles of wire and cable in it and I was responsible for most of that. 271 00:17:56,060 --> 00:18:01,060 And certainly by the end of my PhD, I could swing a sledgehammer. 272 00:18:06,780 --> 00:18:10,780 I was there at the same time and I do remember Jocelyn wrapped up 273 00:18:10,780 --> 00:18:13,900 in a great woolly thick jacket trying to keep warm 274 00:18:13,900 --> 00:18:17,660 as they built this enormous structure in the fields of Cambridgeshire. 275 00:18:22,140 --> 00:18:25,140 We were scanning the sky at intervals, 276 00:18:25,140 --> 00:18:29,460 and we didn't have much in the way of computing. 277 00:18:29,460 --> 00:18:33,220 This was all done with paper charts and pen recorders 278 00:18:33,220 --> 00:18:39,540 and so the chart recorders rolled and the pen records came out 279 00:18:39,540 --> 00:18:44,780 and Jocelyn spend a lot of time poring over these records 280 00:18:44,780 --> 00:18:48,060 and simply logging every twinkling galaxy 281 00:18:48,060 --> 00:18:51,700 that was detectable on the paper. 282 00:18:55,700 --> 00:19:01,260 My system produced 96 feet of paper chart every day. 283 00:19:01,260 --> 00:19:03,180 Great rolls of the stuff. 284 00:19:04,900 --> 00:19:08,980 And then I'd take the paper charts from the observatory 285 00:19:08,980 --> 00:19:11,340 from the telescope to Cambridge 286 00:19:11,340 --> 00:19:15,900 to the Cavendish Laboratory, and us grad students were in an attic. 287 00:19:15,900 --> 00:19:20,260 When Jocelyn would come in with the rolls of paper, 288 00:19:20,260 --> 00:19:22,060 she would stand at one end of the attic, make sure that everybody 289 00:19:22,060 --> 00:19:24,420 cleared their rubbish out down the middle 290 00:19:24,420 --> 00:19:27,260 and she'd ball the paper rolls from one end to the other and get down 291 00:19:27,260 --> 00:19:29,300 and start to examine them. 292 00:19:32,100 --> 00:19:36,780 I had to scan through these charts inch by inch by inch, 293 00:19:36,780 --> 00:19:39,940 looking for twinkling quasars. 294 00:19:39,940 --> 00:19:43,700 I also had to identify interference, 295 00:19:43,700 --> 00:19:47,700 and we had trouble with pirate radio stations. 296 00:19:47,700 --> 00:19:50,620 They were just sort of blasting everything out of existence 297 00:19:50,620 --> 00:19:53,660 as far as we were concerned. 298 00:19:53,660 --> 00:19:56,900 RADIO JINGLES PLAY 299 00:20:01,380 --> 00:20:07,260 And at one point the Home Office allocated to the East Anglia Police 300 00:20:07,260 --> 00:20:10,100 our free, clear radio frequency. 301 00:20:10,100 --> 00:20:15,020 So for about a week we picked up the East Anglia Police and no quasars. 302 00:20:15,020 --> 00:20:18,300 You just couldn't see anything else. 303 00:20:18,300 --> 00:20:21,460 'A1 hold-up, returning to base...' 304 00:20:27,380 --> 00:20:31,860 After I'd been operating the telescope about a month, 305 00:20:31,860 --> 00:20:36,300 I got first sight of a bit of signal that didn't look 306 00:20:36,300 --> 00:20:38,620 totally like a scintillating quasar, 307 00:20:40,180 --> 00:20:43,420 and yet didn't look like interference. 308 00:20:43,420 --> 00:20:47,140 It only occupied about a quarter inch in the 400ft 309 00:20:47,140 --> 00:20:51,660 of chart paper that it took to do a complete Sky Survey. 310 00:20:53,180 --> 00:20:55,380 So I could easily have overlooked it, 311 00:20:55,380 --> 00:20:59,260 but a few weeks later, analysing another piece of chart from another 312 00:20:59,260 --> 00:21:03,100 survey of the sky, I noticed it again. 313 00:21:03,100 --> 00:21:06,060 I got out all my previous records 314 00:21:06,060 --> 00:21:11,900 from that part of the sky and found that on occasion, this curious 315 00:21:11,900 --> 00:21:13,580 quarter inch of signal was there. 316 00:21:13,580 --> 00:21:17,540 One key point was it had a fixed spot amongst the constellations, 317 00:21:17,540 --> 00:21:22,060 so it looked a bit as if it was out there amongst the stars. 318 00:21:22,060 --> 00:21:25,860 I decided to go and talk to Tony, my supervisor, about this. 319 00:21:28,540 --> 00:21:33,580 'I didn't believe that it was necessarily a true recording 320 00:21:33,580 --> 00:21:35,220 'at that stage.' 321 00:21:35,220 --> 00:21:37,540 I mean, we've heard ships being navigated up the Thames 322 00:21:37,540 --> 00:21:41,100 and all sorts of things. You know, we're in a band, a VHF band, 323 00:21:41,100 --> 00:21:43,820 which is being used by all sorts of other people. 324 00:21:45,820 --> 00:21:50,060 Jocelyn said, "It does appear at the same sidereal time." 325 00:21:50,060 --> 00:21:54,660 That's to say it's located like a galaxy would be, 326 00:21:54,660 --> 00:21:57,660 but it wasn't always there. 327 00:21:57,660 --> 00:22:00,780 I mean, we were making sky surveys regularly and sometimes 328 00:22:00,780 --> 00:22:03,020 when the telescope is directed in that direction 329 00:22:03,020 --> 00:22:07,300 there's just nothing to be seen. But one thing was quite clear. 330 00:22:09,180 --> 00:22:12,380 As I was running the system for the survey, this signal took up 331 00:22:12,380 --> 00:22:16,260 this quarter inch and everything was jammed into the quarter inch 332 00:22:16,260 --> 00:22:19,300 and what we needed to do was spread it out. 333 00:22:19,300 --> 00:22:21,140 When you're using a chart recorder 334 00:22:21,140 --> 00:22:26,020 the way you spread things out is you from the paper faster under the pen. 335 00:22:26,020 --> 00:22:29,860 You make an enlargement, basically. 336 00:22:29,860 --> 00:22:35,660 So all we had to do was run the chart paper faster, 337 00:22:35,660 --> 00:22:39,220 and I did this faithfully for the month of November 338 00:22:39,220 --> 00:22:41,700 and the object wasn't showing. 339 00:22:41,700 --> 00:22:45,740 For this whole month, it appeared to have disappeared. 340 00:22:47,580 --> 00:22:51,020 Tony was quite cross. 341 00:22:51,020 --> 00:22:54,220 Grad students are a bit like the cat - they're there for kicking. 342 00:22:54,220 --> 00:22:55,900 "Oh, it's a flair star. 343 00:22:55,900 --> 00:22:59,940 "It's have been and gone and done it and you've missed it!" 344 00:22:59,940 --> 00:23:04,580 But I persisted in going out to the observatory to set up the observation 345 00:23:04,580 --> 00:23:09,100 and the high-speed recording, and held my breath and waited. 346 00:23:14,380 --> 00:23:19,100 Then one day late in November, I actually got it. 347 00:23:27,380 --> 00:23:32,220 And as the paper flowed under the pen, the pen went blip, blip, 348 00:23:32,220 --> 00:23:33,380 blip, blip. 349 00:23:33,380 --> 00:23:37,100 It looked like a series of equally spaced pulses 350 00:23:37,100 --> 00:23:41,620 and once I was able to get the paper off the recorder, 351 00:23:41,620 --> 00:23:45,860 I could see it was a series of equally spaced pulses. 352 00:23:45,860 --> 00:23:48,940 That was totally surprising. 353 00:23:48,940 --> 00:23:51,580 I don't know what I had expected, 354 00:23:51,580 --> 00:23:54,700 but I certainly didn't expect regular pulsations. 355 00:23:54,700 --> 00:23:58,220 Stars and galaxies don't pulse like that. 356 00:23:58,220 --> 00:24:01,860 And that was the afternoon that I phoned Tony Hewish and said, 357 00:24:03,500 --> 00:24:06,140 "Hey, Tony, this curious signal is a string of pulses." 358 00:24:08,700 --> 00:24:11,220 So I said, "Well, don't be stupid. 359 00:24:11,220 --> 00:24:13,140 "It has to be radio interference." 360 00:24:13,140 --> 00:24:17,300 The fact that it was pulsing regularly, I mean, 361 00:24:17,300 --> 00:24:21,380 was just nonsense. True astronomical sources don't do that. 362 00:24:23,620 --> 00:24:25,220 I didn't argue with him. 363 00:24:25,220 --> 00:24:27,660 I wasn't sure I agreed with him. 364 00:24:29,140 --> 00:24:32,380 I knew somehow in my bones 365 00:24:32,380 --> 00:24:35,620 that it wasn't that simple. 366 00:24:35,620 --> 00:24:40,100 I learned something very useful from my time in Glasgow. 367 00:24:40,100 --> 00:24:45,900 The physics students had a Physics Society and we got visiting speakers, 368 00:24:45,900 --> 00:24:49,180 and quite a few of the staff would attend these meetings, 369 00:24:49,180 --> 00:24:52,660 listening to the speakers. And I was the only female in the class 370 00:24:52,660 --> 00:24:56,700 and the guys all asked bright questions to the visiting speaker, 371 00:24:56,700 --> 00:25:01,980 and I thought, if I keep quiet, I'm going to disappear from sight. 372 00:25:01,980 --> 00:25:05,220 I have got to learn to ask questions. 373 00:25:05,220 --> 00:25:08,500 I was quite shy at the time, so it was actually difficult. 374 00:25:08,500 --> 00:25:13,260 But I lit upon a ploy, which I'm actually quite proud of. 375 00:25:13,260 --> 00:25:17,620 I realised that a speaker in the first five minutes sets out 376 00:25:17,620 --> 00:25:19,860 the rudiments of their stall 377 00:25:19,860 --> 00:25:26,500 and may or may not make clear what assumptions they've made. 378 00:25:26,500 --> 00:25:29,740 And they then go on to build on this. 379 00:25:29,740 --> 00:25:33,260 If I listened like fury for the first five minutes 380 00:25:33,260 --> 00:25:37,460 and tried to spot what assumptions they had made, 381 00:25:37,460 --> 00:25:40,860 you can then ask a devastating question at the end. 382 00:25:40,860 --> 00:25:44,260 "You've assumed, sir, such and such and such and such. 383 00:25:44,260 --> 00:25:47,940 "If that's not true, how much does it affect your conclusions?" 384 00:25:47,940 --> 00:25:51,140 And the rest of the audience goes, ah! 385 00:25:51,140 --> 00:25:54,460 And it works, every time. 386 00:25:54,460 --> 00:25:57,460 And that was the ploy I adopted as an undergraduate 387 00:25:57,460 --> 00:26:04,380 as a survival technique. Sometimes in research you can know too much, 388 00:26:04,380 --> 00:26:07,820 and it's the youngster who's ignorant or somebody coming in from 389 00:26:07,820 --> 00:26:11,300 outside that says, "You know, the Emperor has no clothes on", 390 00:26:11,300 --> 00:26:14,100 that, actually, is telling the truth. 391 00:26:14,100 --> 00:26:15,660 Can see the truth. 392 00:26:18,100 --> 00:26:22,460 When I phoned Tony that first afternoon to say, "Hey, Tony, 393 00:26:22,460 --> 00:26:24,500 "you know that funny new source? 394 00:26:24,500 --> 00:26:28,220 "It's pulsing with a period of one and a third seconds." 395 00:26:28,220 --> 00:26:34,220 Tony knew more astrophysics than I did, and he knew that it meant 396 00:26:34,220 --> 00:26:37,180 that that object was very, very small, star-sized. 397 00:26:37,180 --> 00:26:42,460 Until then, radio astronomers hadn't seen strong signals from stars. 398 00:26:42,460 --> 00:26:47,220 They didn't believe stars were radio sources, so there was a problem. 399 00:26:47,220 --> 00:26:50,260 I knew less astrophysics. 400 00:26:50,260 --> 00:26:54,700 I wasn't bothered about the object's size. I thought, "interesting". 401 00:26:54,700 --> 00:26:58,180 There was no denying the existence of the mysterious pulses, 402 00:26:58,180 --> 00:27:03,620 but were they real or simply an experimental artefact? 403 00:27:03,620 --> 00:27:05,380 A fault in her telescope? 404 00:27:05,380 --> 00:27:09,780 One of the first things we wanted to do was see 405 00:27:09,780 --> 00:27:13,260 whether it was some fluke of my equipment, 406 00:27:13,260 --> 00:27:16,380 and I was afraid that literally I had got some wires crossed 407 00:27:16,380 --> 00:27:18,180 or done something stupid like that. 408 00:27:18,180 --> 00:27:23,180 And so we enlisted the help of Robin Collins and his supervisor Paul Scott 409 00:27:23,180 --> 00:27:27,020 to see if their radio telescope could pick up this pulsing signal. 410 00:27:27,020 --> 00:27:29,380 The way the telescopes were aligned, 411 00:27:29,380 --> 00:27:34,340 my telescope looked at that bit of sky shortly before theirs did. 412 00:27:34,340 --> 00:27:35,980 20 minutes or something. 413 00:27:35,980 --> 00:27:39,940 We could see it pulsing nicely with my telescope 414 00:27:39,940 --> 00:27:43,300 and then we went and stood by Robin's pen recorder. 415 00:27:49,300 --> 00:27:52,700 And we stood by this pen recorder, 416 00:27:52,700 --> 00:27:56,100 and waited and waited and waited... 417 00:27:58,700 --> 00:28:00,820 and nothing happened. 418 00:28:00,820 --> 00:28:03,580 Oh, my God. 419 00:28:07,860 --> 00:28:11,740 Tony and Paul, the two academic staff, 420 00:28:11,740 --> 00:28:15,580 started walking down this very long laboratory and I was padding along 421 00:28:15,580 --> 00:28:20,020 behind them trying to keep up with them, in every sense of the word. 422 00:28:20,020 --> 00:28:22,740 Robin stayed by the pen recorder 423 00:28:22,740 --> 00:28:27,140 and we'd just got down the end of this long laboratory, 424 00:28:27,140 --> 00:28:30,380 and there was a strangled cry from Robin, "Here it is!" 425 00:28:30,380 --> 00:28:32,620 and we came charging back up the lab 426 00:28:32,620 --> 00:28:35,820 and there it was - pulse, pulse, pulse, pulse, pulse, pulse. 427 00:28:45,220 --> 00:28:49,700 We had actually miscalculated when it would appear in Robin's telescope 428 00:28:49,700 --> 00:28:54,180 and we had been out by five minutes, or so. 429 00:28:54,180 --> 00:28:58,220 Fortunately, only five minutes. If we'd been out by a longer interval, 430 00:28:58,220 --> 00:29:01,460 we might have given up and gone home and the story 431 00:29:01,460 --> 00:29:03,220 would've been very, very different. 432 00:29:05,340 --> 00:29:08,100 I'm waiting for an intelligible message from space and here is one! 433 00:29:08,100 --> 00:29:09,100 Is it intelligible? Yes! 434 00:29:09,100 --> 00:29:12,340 You can decipher it? Oh, do you think the cosmos is inhabited 435 00:29:12,340 --> 00:29:15,020 by a load of boy scouts sending Morse code? 436 00:29:15,020 --> 00:29:18,140 What is this, Dennis? Is it a message? Have a look. Let me see. 437 00:29:18,140 --> 00:29:20,700 Could be from a distant probe. 438 00:29:20,700 --> 00:29:22,940 Or another planet. 439 00:29:26,180 --> 00:29:28,900 Yes. 440 00:29:28,900 --> 00:29:32,100 I remember talking to a very learned friend, Sir Edward Bullard, 441 00:29:32,100 --> 00:29:33,340 a famous geophysicist. 442 00:29:33,340 --> 00:29:37,340 I said "Look, we're getting this very strange signal, seems to have 443 00:29:37,340 --> 00:29:41,700 "fixed co-ordinates in the sky, but it's a series of regular pulses". 444 00:29:41,700 --> 00:29:44,140 And of course the question mark 445 00:29:44,140 --> 00:29:48,820 was in our minds too, could it be intelligence or something? 446 00:29:48,820 --> 00:29:51,340 He said, "Simplest explanation - 447 00:29:51,340 --> 00:29:54,900 "look and see if it's a single frequency 448 00:29:54,900 --> 00:29:58,540 "and then it's probably 99% an intelligent signal". 449 00:29:58,540 --> 00:30:00,540 You know, 450 00:30:00,540 --> 00:30:02,780 radio signals naturally emitted 451 00:30:02,780 --> 00:30:07,300 cover a whole broad range of radio frequencies. 452 00:30:07,300 --> 00:30:13,180 But it's intelligent things that radiate on a single frequency. 453 00:30:13,180 --> 00:30:17,660 And that's what it turned out to be...and the intelligent signal 454 00:30:17,660 --> 00:30:23,140 became more real. Things were all getting rather tense at that stage. 455 00:30:27,300 --> 00:30:30,940 I went down to Tony's office late one evening to ask him 456 00:30:30,940 --> 00:30:34,860 about something, and rather unusually, the door was shut. 457 00:30:34,860 --> 00:30:38,580 Tony normally had an open door policy. 458 00:30:38,580 --> 00:30:42,220 So I knocked, and a voice said, "Come in", and I poked my head 459 00:30:42,220 --> 00:30:47,460 round the door, and Tony said "Ah, Jocelyn, come in and shut the door." 460 00:30:47,460 --> 00:30:50,460 And there was a high-level meeting going on in there. 461 00:30:50,460 --> 00:30:54,820 There was Tony, there was Martin Ryle, the Professor, the head 462 00:30:54,820 --> 00:30:58,700 of the group, and one other senior person and it was a discussion 463 00:30:58,700 --> 00:31:02,660 that I think I should have been in on, actually, from the beginning. 464 00:31:05,580 --> 00:31:09,260 We thought this was bigger than we want to handle ourselves. 465 00:31:09,260 --> 00:31:12,780 We don't want to just give it to the press, this has to be done properly. 466 00:31:12,780 --> 00:31:16,980 And I discussed this with Martin Ryle because I was wondering what to do... 467 00:31:16,980 --> 00:31:23,260 and he was half joking, but he said, "Burn the records, and forget about it". 468 00:31:23,260 --> 00:31:28,180 Because he said, "If the news gets out 469 00:31:28,180 --> 00:31:30,060 "that there's intelligence... 470 00:31:30,060 --> 00:31:35,540 "out there, what is going to happen"? People will want to launch 471 00:31:35,540 --> 00:31:39,700 a signal in that direction, to talk to them or something, 472 00:31:39,700 --> 00:31:44,580 and he said, "Supposing all they're doing on that distant planet 473 00:31:44,580 --> 00:31:47,620 "is looking for a reply somewhere, 474 00:31:47,620 --> 00:31:49,380 "so if they, they're overcrowded, 475 00:31:49,380 --> 00:31:53,540 "they're looking for a nice, young, green planet that they can occupy, 476 00:31:53,540 --> 00:31:59,020 "that's what it's all about, and the next thing is, you'll be invaded". 477 00:32:04,460 --> 00:32:06,580 We didn't solve it that evening 478 00:32:06,580 --> 00:32:12,300 and I went home to get supper, and I was really getting pretty cross. 479 00:32:12,300 --> 00:32:16,660 My money was running out, I wanted to get a thesis done, get my PhD 480 00:32:16,660 --> 00:32:21,020 and there was some silly lot of little green men choosing 481 00:32:21,020 --> 00:32:23,380 my radio telescope and my frequency 482 00:32:23,380 --> 00:32:26,220 to signal to earth, you know, how dare they, kind of thing. 483 00:32:27,860 --> 00:32:31,140 I got some supper and felt I had to come back to work. 484 00:32:31,140 --> 00:32:35,580 With all the special observations on the pulsars, the twinkling quasars 485 00:32:35,580 --> 00:32:40,500 had been rather neglected and there was a huge backlog of these 486 00:32:40,500 --> 00:32:42,700 survey charts to be analysed... 487 00:32:42,700 --> 00:32:47,780 and at about quarter to ten at night I was analysing a chart 488 00:32:47,780 --> 00:32:51,820 from another piece of sky and thought I saw a piece 489 00:32:51,820 --> 00:32:54,460 of this scruffy kind of signal. 490 00:32:54,460 --> 00:32:57,860 Looked exactly like what I was seeing before, but from 491 00:32:57,860 --> 00:33:00,620 a totally different bit of the sky. 492 00:33:00,620 --> 00:33:04,620 Right. I thought, I'm not going to bed tonight, 493 00:33:04,620 --> 00:33:07,540 I'm going out to the observatory. 494 00:33:15,780 --> 00:33:19,180 That bit of the sky was due to go through the telescope beam 495 00:33:19,180 --> 00:33:21,460 at 2.00, 3.00 in the morning... 496 00:33:21,460 --> 00:33:25,140 December 21st, perishing cold. 497 00:33:33,660 --> 00:33:38,100 And I switched on the high-speed recorder and it came, 498 00:33:38,100 --> 00:33:41,780 blip, blip, blip, blip. Clearly the same family. 499 00:33:41,780 --> 00:33:43,860 The same sort of stuff. 500 00:33:43,860 --> 00:33:48,420 And that was great. That was really sweet. 501 00:33:48,420 --> 00:33:51,300 It finally scotched the little green men hypothesis, 502 00:33:51,300 --> 00:33:55,380 as it's highly unlikely there's two lots of little green men, 503 00:33:55,380 --> 00:33:57,660 opposite sides of the universe, 504 00:33:57,660 --> 00:34:02,300 both deciding to signal to a rather inconspicuous Planet Earth 505 00:34:02,300 --> 00:34:08,580 at the same time, using a daft technique and commonplace frequency. 506 00:34:12,060 --> 00:34:17,100 It has to be some new kind of star not seen before. 507 00:34:18,580 --> 00:34:22,620 And that then cleared the way for us publishing, going public. 508 00:34:25,580 --> 00:34:28,980 Martin Ryle called up the editor of Nature, John Maddox, 509 00:34:28,980 --> 00:34:32,780 and more or less said, "We've got something interesting coming". 510 00:34:32,780 --> 00:34:36,020 He didn't quite say "hold the presses" but he nearly did. 511 00:34:36,020 --> 00:34:41,100 Now the people here say that if they got three signals as exactly spaced 512 00:34:41,100 --> 00:34:43,940 as that, it would be very unusual. 513 00:34:43,940 --> 00:34:46,820 If they got four, it would be phenomenal. 514 00:34:46,820 --> 00:34:49,620 Well, they've had pulses as exactly spaced as that, 515 00:34:49,620 --> 00:34:52,260 24 hours of the day since November. 516 00:34:55,740 --> 00:34:59,580 Well, these signals that we're picking up are entirely new. 517 00:34:59,580 --> 00:35:04,060 Nothing like this has been seen in radio astronomy before. 518 00:35:04,060 --> 00:35:08,740 The excitement was because this was a totally unexpected, 519 00:35:08,740 --> 00:35:10,980 totally new kind of object behaving 520 00:35:10,980 --> 00:35:15,420 in a way that astronomers had never expected, never dreamed of. 521 00:35:17,660 --> 00:35:20,940 Here is a discovery which illustrates the Universe 522 00:35:20,940 --> 00:35:24,580 is far more complex than we at present believe. 523 00:35:24,580 --> 00:35:28,660 That month, that was a real high point... 524 00:35:28,660 --> 00:35:31,140 and when I wrote that Nature letter, 525 00:35:31,140 --> 00:35:35,460 I thought, my God, that's pretty good actually. Ha, ha, ha! 526 00:35:35,460 --> 00:35:38,100 There's a lot in there. Yeah. 527 00:35:43,380 --> 00:35:47,460 Seeing the article in print was tremendous. 528 00:35:47,460 --> 00:35:52,180 And I remember sending a copy of the paper to my physics teacher. 529 00:35:54,620 --> 00:35:57,860 And that's your physics teacher at the Mount? At the Mount, yes. 530 00:35:57,860 --> 00:35:59,500 My physics teacher at the Mount. 531 00:35:59,500 --> 00:36:05,580 And how did he react to it? He had actually alerted the school. 532 00:36:09,060 --> 00:36:10,900 There was a lot of publicity, 533 00:36:10,900 --> 00:36:14,140 Mr Tillett had seen this and told the school. 534 00:36:16,580 --> 00:36:21,660 There aren't so many people that take up physics as a profession and 535 00:36:21,660 --> 00:36:27,140 certainly relatively few women of my generation, so Mr Tillett followed 536 00:36:27,140 --> 00:36:29,580 with some interest my career. 537 00:36:29,580 --> 00:36:32,980 And I was really pleased that he was still around 538 00:36:32,980 --> 00:36:35,260 at the time of the discovery. 539 00:36:39,860 --> 00:36:44,580 The family was just...amazed. 540 00:36:44,580 --> 00:36:47,660 Absolutely. 541 00:36:47,660 --> 00:36:51,300 And proud? Very proud. 542 00:36:54,780 --> 00:36:58,460 Despite the obvious importance of Jocelyn Bell's discovery, 543 00:36:58,460 --> 00:37:02,300 the mysterious bursts of energy still hadn't been named. 544 00:37:02,300 --> 00:37:05,900 We hadn't really thought of a name for these things, so this journalist 545 00:37:05,900 --> 00:37:10,420 who was from the Daily Telegraph said, "What about 'pulsar', 546 00:37:10,420 --> 00:37:14,060 "as an abbreviation for Pulsating Radio Star"? 547 00:37:14,060 --> 00:37:17,620 And he wrote it up on the board in the office where we were meeting. 548 00:37:17,620 --> 00:37:20,260 And we looked at it and thought, "Oh yeah, that looks OK". 549 00:37:20,260 --> 00:37:23,100 If only a very few pulsars have been discovered so far, 550 00:37:23,100 --> 00:37:25,900 and they are all very close to the sun, comparatively speaking, 551 00:37:25,900 --> 00:37:29,780 does this mean there are vast numbers of them throughout the galaxy? 552 00:37:29,780 --> 00:37:32,580 Yes, if they're distributed throughout the galaxy in the way 553 00:37:32,580 --> 00:37:34,900 we find them close to the sun, 554 00:37:34,900 --> 00:37:37,940 there must be millions of them in our own galaxy. 555 00:37:37,940 --> 00:37:41,860 And of course, the most important question of all, what are they? 556 00:37:41,860 --> 00:37:44,260 Well, we know that they're very small, they're objects 557 00:37:44,260 --> 00:37:46,180 about the size of a planet. 558 00:37:46,180 --> 00:37:49,420 We know also that they're very energetic and that the source 559 00:37:49,420 --> 00:37:52,860 of energy must be far greater than a planet could really provide. 560 00:37:52,860 --> 00:37:56,820 Something like a star, compressed into a volume the size of a planet. 561 00:38:02,860 --> 00:38:05,060 To work out what pulsars are, 562 00:38:05,060 --> 00:38:08,900 we had to go back to exploding stars, the supernovae. 563 00:38:15,340 --> 00:38:20,260 It used to be assumed that a supernova was a total catastrophic 564 00:38:20,260 --> 00:38:24,660 destruction of the star, with everything dispersing out into space. 565 00:38:27,580 --> 00:38:29,820 However, in the 1930s, an astronomer, 566 00:38:29,820 --> 00:38:35,380 a Swiss astronomer called Zwicky, a guy who had a lot of ideas, 567 00:38:35,380 --> 00:38:39,860 a very creative mind, reckoned that when these supernovae occurred, 568 00:38:39,860 --> 00:38:45,820 the core of the star got shrunk right down to make this very dense ball, 569 00:38:45,820 --> 00:38:51,340 and it would be rich in neutrons, so it was called a neutron star. 570 00:38:51,340 --> 00:38:55,220 Neutron stars were a pretty wild idea, 571 00:38:55,220 --> 00:38:57,220 nobody took them very seriously, 572 00:38:57,220 --> 00:39:01,860 and I don't know that people took Zwicky very seriously either. 573 00:39:01,860 --> 00:39:06,380 But we now know, following the discovery of pulsars, that there are 574 00:39:06,380 --> 00:39:11,140 these objects left behind, because it turns out that the pulsars are indeed 575 00:39:11,140 --> 00:39:13,700 neutron stars, and Zwicky was right. 576 00:39:13,700 --> 00:39:16,620 This is what we believe the neutron star will look like. 577 00:39:16,620 --> 00:39:21,180 The neutron star is an incredibly compact thing. 578 00:39:21,180 --> 00:39:24,780 These lines show you the direction of the magnetic field 579 00:39:24,780 --> 00:39:26,980 close to the neutron star. 580 00:39:26,980 --> 00:39:31,140 They've a very strong magnetic field, perhaps a million, million times 581 00:39:31,140 --> 00:39:32,980 the Earth's magnetic field... 582 00:39:35,380 --> 00:39:39,100 And it seems that coming from the magnetic north and south poles, 583 00:39:39,100 --> 00:39:41,380 there's a beam of radio waves. 584 00:39:41,380 --> 00:39:46,100 And as the star spins, this beam gets swept round the sky 585 00:39:46,100 --> 00:39:48,100 like a lighthouse beam... 586 00:39:48,100 --> 00:39:52,300 and each time a beam sweeps across the Earth, we see a pulse. 587 00:39:52,300 --> 00:39:55,940 So if you get a pulsar going four times a second, 588 00:39:55,940 --> 00:39:58,580 it means it's spinning four times a second. 589 00:39:58,580 --> 00:40:03,460 If you get a pulsar 600 times a second, it's spinning 600 times 590 00:40:03,460 --> 00:40:08,780 a second, which beggars imagination, but that's what seems to be the case. 591 00:40:11,780 --> 00:40:15,620 The faint blips from space so nearly dismissed as error 592 00:40:15,620 --> 00:40:17,900 took the world by storm. 593 00:40:17,900 --> 00:40:22,180 And any astronomer worth his salt wanted a piece of the action. 594 00:40:22,180 --> 00:40:26,620 Observing pulsars is like listening to a Beethoven symphony. 595 00:40:26,620 --> 00:40:29,940 There's the rhythm of the pulses themselves, 596 00:40:29,940 --> 00:40:33,540 and within the pulses, a complicated pattern of notes. 597 00:40:33,540 --> 00:40:34,940 Sometimes at one frequency, 598 00:40:34,940 --> 00:40:39,780 sometimes at another, just as in the melody of a musical composition. 599 00:40:39,780 --> 00:40:43,900 All of a sudden, people went from thinking about stars 600 00:40:43,900 --> 00:40:48,100 as being unchanging, the Universe being relatively dull and boring, 601 00:40:48,100 --> 00:40:53,420 to suddenly, the Universe is full of these things flickering 602 00:40:53,420 --> 00:40:57,820 and flashing around, extremely energetic, very exciting. 603 00:41:01,980 --> 00:41:05,820 Pulsars were important but they were an enabling discovery, because 604 00:41:05,820 --> 00:41:09,460 it actually showed that not only did these ideas exist theoretically, 605 00:41:09,460 --> 00:41:11,780 but they could actually be seen 606 00:41:11,780 --> 00:41:14,740 and it allowed us to tie down many of the theoretical ideas 607 00:41:14,740 --> 00:41:16,620 that were in vogue at the time. 608 00:41:20,620 --> 00:41:25,540 Stephen Hawking got on to me and said how delighted he was, congratulations 609 00:41:25,540 --> 00:41:30,060 and so on, and he said, "Well, if neutron stars exist, 610 00:41:30,060 --> 00:41:32,700 "you must believe strongly in black holes". 611 00:41:32,700 --> 00:41:35,460 "I mean, a neutron star is so close to being a black hole, 612 00:41:35,460 --> 00:41:38,740 "that if neutron stars are there then there's no question 613 00:41:38,740 --> 00:41:40,940 "that black holes are there too". 614 00:41:46,300 --> 00:41:49,100 It's all do with the mass of the star that's collapsing. 615 00:41:49,100 --> 00:41:50,980 If the star is about the size 616 00:41:50,980 --> 00:41:54,620 of the sun, it's going to form a white dwarf, where it's held up 617 00:41:54,620 --> 00:41:58,100 by the pressure of the material inside it. 618 00:41:58,100 --> 00:42:02,420 If the star is more dense, it actually will form a neutron star, 619 00:42:02,420 --> 00:42:06,780 where the neutrons themselves are the thing providing basic pressure. 620 00:42:08,900 --> 00:42:13,260 If there's even more mass, the neutrons themselves 621 00:42:13,260 --> 00:42:15,900 aren't strong enough to hold up 622 00:42:15,900 --> 00:42:20,980 against gravity. The star collapses further and you get a black hole. 623 00:42:23,780 --> 00:42:26,860 I mean, black holes were a bit of a joke in those days. 624 00:42:26,860 --> 00:42:29,700 You know, Steven Hawking was making these outrageous suggestions, 625 00:42:29,700 --> 00:42:33,780 and so on, and people didn't take black holes at all seriously. 626 00:42:33,780 --> 00:42:35,780 But I think after that, they did. 627 00:42:45,980 --> 00:42:49,980 Like many scientific discoveries, it took an open-minded researcher 628 00:42:49,980 --> 00:42:53,860 to realise there was something there to be discovered. 629 00:42:53,860 --> 00:42:57,900 It was a quality which had been instilled in Jocelyn Bell Burnell 630 00:42:57,900 --> 00:43:03,220 from an early age. I was born into a Quaker family. 631 00:43:03,220 --> 00:43:08,300 My son, who's done the research, says I am ninth-generation Quaker. 632 00:43:08,300 --> 00:43:13,820 I've been active in Quakers all my life, and still am. 633 00:43:18,260 --> 00:43:25,260 I find that Quakerism and research science fit together very very well. 634 00:43:25,260 --> 00:43:30,260 In Quakerism you're expected to develop your own understanding of God 635 00:43:30,260 --> 00:43:33,580 from your experience in the world. 636 00:43:33,580 --> 00:43:36,340 There isn't a creed, there isn't a dogma. 637 00:43:36,340 --> 00:43:42,060 There's an understanding, but nothing as formal as a dogma or creed. 638 00:43:44,220 --> 00:43:49,380 And this idea that you develop your own understanding also means that you 639 00:43:49,380 --> 00:43:53,620 keep redeveloping your understanding as you get more experience. 640 00:43:53,620 --> 00:43:58,700 It seems to me that's very like what goes on in "the scientific method". 641 00:43:58,700 --> 00:44:02,860 You have a model of a star, it's an understanding, 642 00:44:02,860 --> 00:44:09,020 and develop that model in the light of experiments and observations. 643 00:44:09,020 --> 00:44:13,220 And so in both, you're expected to evolve your thinking. 644 00:44:13,220 --> 00:44:16,300 Nothing is static. Nothing is final. 645 00:44:16,300 --> 00:44:19,180 Everything is held provisionally. 646 00:44:23,060 --> 00:44:25,300 Through history, we have seen some theories 647 00:44:25,300 --> 00:44:29,940 that have stood the test of time well and some that disappeared quickly. 648 00:44:29,940 --> 00:44:35,220 A theory that stands the test of time well will have been prodded 649 00:44:35,220 --> 00:44:41,460 and poked and battered and examined from every angle and still stands up. 650 00:44:41,460 --> 00:44:45,580 and Einstein's theory of relativity is one of those that's been subject 651 00:44:45,580 --> 00:44:50,900 to a lot of scrutiny, but it was only following the discovery 652 00:44:50,900 --> 00:44:56,580 of pulsars that it was possible to test Einstein's ideas about gravity. 653 00:44:56,580 --> 00:45:00,620 Einstein's theories predict that where you have a pair of stars 654 00:45:00,620 --> 00:45:05,500 orbiting each other, this system produces a new kind of radiation, 655 00:45:05,500 --> 00:45:08,300 gravitational radiation, or gravitational waves, 656 00:45:08,300 --> 00:45:12,980 and the effects of these waves being produced are that the two stars move 657 00:45:12,980 --> 00:45:17,180 closer together and go round faster, which sends out more gravity waves, 658 00:45:17,180 --> 00:45:20,740 so they move closer together and go round even faster, 659 00:45:20,740 --> 00:45:23,180 and they actually end up merging. 660 00:45:23,180 --> 00:45:27,220 With the first pulsar discovered in one of these binary systems, 661 00:45:27,220 --> 00:45:32,540 they've been able to track the orbit and they have seen that the stars 662 00:45:32,540 --> 00:45:37,580 do move closer together, in exactly the manner predicted by Einstein. 663 00:45:41,260 --> 00:45:45,060 So does that mean that Einstein's been proved right, then? 664 00:45:45,060 --> 00:45:49,380 The current situation is that the pulsar astronomers have 665 00:45:49,380 --> 00:45:55,660 shown that Einstein's theory of gravity is right to about 0.02%. 666 00:45:55,660 --> 00:46:01,460 That's not the same as saying it's true though, is it? 667 00:46:01,460 --> 00:46:07,220 Scientists should never claim that something is absolutely true. 668 00:46:07,220 --> 00:46:11,380 You should never claim perfect or total or 100%, 669 00:46:11,380 --> 00:46:14,580 because you never, ever get there. 670 00:46:17,020 --> 00:46:20,340 Is science therefore not a quest for the truth? 671 00:46:20,340 --> 00:46:23,460 Science is a quest for understanding. 672 00:46:23,460 --> 00:46:27,500 A search for truth seems to me to be full of pitfalls. 673 00:46:27,500 --> 00:46:29,060 We all have different understandings 674 00:46:29,060 --> 00:46:34,020 of what truth is, and we each believe or we're in danger of each believing 675 00:46:34,020 --> 00:46:37,660 that our truth is the one and only absolute truth, 676 00:46:37,660 --> 00:46:40,980 which is why I say it's full of pitfalls. 677 00:46:40,980 --> 00:46:47,540 I think a search for understanding is much more serviceable to humankind 678 00:46:47,540 --> 00:46:51,220 and is a sufficiently ambitious goal of itself. 679 00:46:51,740 --> 00:46:55,780 Jocelyn Bell Burnell has devoted her life 680 00:46:55,780 --> 00:46:57,820 to the search for understanding. 681 00:46:57,820 --> 00:47:02,500 After completing her PhD, she settled into the world of academia, 682 00:47:02,500 --> 00:47:06,980 continuing her research into the behaviour of stars. 683 00:47:06,980 --> 00:47:10,420 I have very vivid memories 684 00:47:10,420 --> 00:47:13,740 of October 10th, 1974. 685 00:47:13,740 --> 00:47:19,980 I was working with a satellite called Ariel V that was launching 686 00:47:19,980 --> 00:47:23,740 from off the coast of Kenya on the morning of 10th October. 687 00:47:28,180 --> 00:47:32,380 At about 12.05 that morning, one of my colleagues came steaming 688 00:47:32,380 --> 00:47:35,180 into the office, "Have you heard the news?!" 689 00:47:35,180 --> 00:47:39,140 No, John, what news? Something wrong with Ariel V? 690 00:47:39,140 --> 00:47:41,860 "No, the Nobel Prize." 691 00:47:41,860 --> 00:47:46,540 His wife had been listening at home to the news and had phoned him up 692 00:47:46,540 --> 00:47:51,180 and told him Martin Ryle and Tony Hewish had got the Nobel Prize. 693 00:47:51,180 --> 00:47:53,940 And John was along, I think, 694 00:47:53,940 --> 00:47:58,060 hoping to see steam come out of my ears. 695 00:47:58,060 --> 00:48:02,420 Well, that was just a total, huge surprise. 696 00:48:05,460 --> 00:48:09,740 I just hadn't the faintest idea it was going to happen like that, 697 00:48:09,740 --> 00:48:14,180 and to get it with Martin Ryle was a double pleasure, 698 00:48:14,180 --> 00:48:19,860 because he was a wonderful man, and the sadness was that he wasn't able 699 00:48:19,860 --> 00:48:22,700 himself to go and collect the prize. 700 00:48:22,700 --> 00:48:25,180 Professor Antony Hewish. 701 00:48:26,780 --> 00:48:32,100 The discovery of pulsars, for which you played a decisive role, 702 00:48:32,100 --> 00:48:37,580 is a most outstanding example of how, in recent years, our knowledge 703 00:48:37,580 --> 00:48:41,220 of the Universe has been dramatically extended. 704 00:48:41,220 --> 00:48:44,580 It just is a wonderful experience. 705 00:48:44,580 --> 00:48:48,540 TRUMPET FANFARE APPLAUSE 706 00:49:00,300 --> 00:49:06,180 Other people were annoyed on my behalf, it has to be said. 707 00:49:06,180 --> 00:49:10,260 And there were puns about "No Bell", 708 00:49:10,260 --> 00:49:15,260 punning on my maiden name, Bell, the "No Bell Prize". 709 00:49:15,260 --> 00:49:21,860 I was slightly saddened that Jocelyn Bell has not received an equal... 710 00:49:21,860 --> 00:49:26,740 recognition of her contribution, which I think was central. 711 00:49:26,740 --> 00:49:30,100 And I think it was, there were many people who felt it was rather sad, 712 00:49:30,100 --> 00:49:33,820 and that perhaps she should have been up there with the others. 713 00:49:33,820 --> 00:49:39,100 There was some disappointment about that at the time. 714 00:49:39,100 --> 00:49:42,580 I mean, my analogy really is a little bit like... 715 00:49:42,580 --> 00:49:48,820 when you plan a ship of discovery and you go off... 716 00:49:48,820 --> 00:49:54,020 and somebody up the mast head says, "Land ho..." 717 00:49:54,020 --> 00:49:57,420 That's great, but I mean, 718 00:49:57,420 --> 00:50:01,660 who actually inspired it, conceived it and decided 719 00:50:01,660 --> 00:50:05,780 what to do when, and so on. 720 00:50:05,780 --> 00:50:09,580 I mean, there is a difference between skipper and crew. 721 00:50:11,100 --> 00:50:15,260 To be honest, I don't think it would have mattered who'd been my student. 722 00:50:15,260 --> 00:50:19,100 I mean, it was a serendipitous discovery, because such a piece 723 00:50:19,100 --> 00:50:21,580 of equipment had been set up. 724 00:50:21,580 --> 00:50:24,980 I mean, the discovery of pulsars was unavoidable 725 00:50:24,980 --> 00:50:27,420 once that survey had begun. 726 00:50:29,700 --> 00:50:31,340 Serendipity is very important, 727 00:50:31,340 --> 00:50:35,780 but I think you shouldn't exaggerate how important it is. 728 00:50:35,780 --> 00:50:39,220 It would have been very easy for Jocelyn just to simply ignore that 729 00:50:39,220 --> 00:50:44,020 and put it in the not-interesting bracket interference box... 730 00:50:44,020 --> 00:50:45,940 but she didn't do that. 731 00:50:45,940 --> 00:50:50,420 What Jocelyn had done was recognise that there was something happening, 732 00:50:50,420 --> 00:50:52,660 and happening in a repetitive manner 733 00:50:52,660 --> 00:50:56,660 I suspect that perhaps only one in 100 people, 734 00:50:56,660 --> 00:50:59,300 given the same circumstances, would have spotted it. 735 00:50:59,300 --> 00:51:03,820 It's not as though it's something that everybody would spot. 736 00:51:03,820 --> 00:51:07,140 She kept, I think, perhaps more meticulous records than probably 737 00:51:07,140 --> 00:51:10,860 her supervisor might have expected about what was going on. 738 00:51:10,860 --> 00:51:14,380 And I think that they provided the core evidence that really drove 739 00:51:14,380 --> 00:51:18,540 the whole discovery of pulsars. So yes, she was lucky she was there. 740 00:51:18,540 --> 00:51:22,180 But if she hadn't done it, it may have been many years before anybody 741 00:51:22,180 --> 00:51:24,940 got round to it seriously. 742 00:51:25,740 --> 00:51:30,020 One of the questions it's always interesting to ask 743 00:51:30,020 --> 00:51:33,260 is why weren't pulsars discovered earlier? 744 00:51:33,260 --> 00:51:37,220 And in fact, they were seen earlier, 745 00:51:37,220 --> 00:51:39,540 but not recognised. 746 00:51:39,540 --> 00:51:44,500 And there are a number of stories around about people who saw pulsars, 747 00:51:44,500 --> 00:51:47,900 but didn't realise what they were seeing and didn't follow it through. 748 00:51:50,340 --> 00:51:55,420 The earliest one I know comes from the late '50s, I believe, 749 00:51:55,420 --> 00:51:59,420 at an optical telescope which was open to the public 750 00:51:59,420 --> 00:52:03,540 and the telescope was trained on that funny star in the middle 751 00:52:03,540 --> 00:52:06,660 of the Crab Nebula known as Minkowski's Star. 752 00:52:06,660 --> 00:52:10,940 A young woman stepped up to the telescope and said, 753 00:52:10,940 --> 00:52:14,780 "That star's flashing." Elliot Moore, the professional astronomer, 754 00:52:14,780 --> 00:52:18,540 who was on duty that night, explained to this woman, you know, 755 00:52:18,540 --> 00:52:20,220 that stars scintillate, twinkle. 756 00:52:20,220 --> 00:52:26,700 She said, "I'm a pilot, I hold an aeroplane pilot's licence, 757 00:52:26,700 --> 00:52:31,940 "I know about scintillation, twinkling...that star's flashing." 758 00:52:31,940 --> 00:52:34,620 Now the pulsar in the Crab Nebula, 759 00:52:34,620 --> 00:52:38,460 which is what Minkowski's Star actually is, flashes 30 times 760 00:52:38,460 --> 00:52:44,620 a second, which is very very fast, and a lot of people can't see that. 761 00:52:44,620 --> 00:52:46,860 But actually, some people can. 762 00:52:46,860 --> 00:52:52,500 I think she probably did see it and I think Elliot Moore believes she did, 763 00:52:52,500 --> 00:52:56,500 but it wasn't followed through, it wasn't published, it wasn't recorded. 764 00:52:58,780 --> 00:53:00,940 What's happening with it now? 765 00:53:00,940 --> 00:53:05,300 The girl who started all the fuss about the pulsars, Jocelyn Bell. 766 00:53:05,300 --> 00:53:09,340 Our picture of how science is done has changed markedly. 767 00:53:09,340 --> 00:53:14,420 The picture used to be that there was a senior man, it always was a man, 768 00:53:14,420 --> 00:53:17,460 who had charge of a whole team of people. 769 00:53:17,460 --> 00:53:20,420 And the people in the team weren't expected to think, 770 00:53:20,420 --> 00:53:26,020 they just did what the boss told them. And if that is the true picture 771 00:53:26,020 --> 00:53:31,180 then it's quite fair that the boss takes the blame or the credit. 772 00:53:31,180 --> 00:53:33,660 But these days we have a different picture. 773 00:53:33,660 --> 00:53:37,780 We have much more a picture of a team of people working together, 774 00:53:37,780 --> 00:53:43,020 each contributing from their own strength, each adding ideas, 775 00:53:43,020 --> 00:53:45,900 a much more egalitarian picture. 776 00:53:45,900 --> 00:53:48,580 I think when I was a grad student 777 00:53:48,580 --> 00:53:52,420 that was actually what was happening but in an unrecognised way. 778 00:53:52,420 --> 00:53:57,300 We were still in the old 1920s, 1930s picture. 779 00:53:57,300 --> 00:54:00,140 Although that wasn't really what was happening. 780 00:54:00,140 --> 00:54:03,780 It's almost like it was the intellectual property 781 00:54:03,780 --> 00:54:08,860 of the university and therefore it was the heads of department 782 00:54:08,860 --> 00:54:11,500 who were recognised for it. 783 00:54:11,500 --> 00:54:16,380 She is remarkably calm and unbothered about it and... 784 00:54:19,020 --> 00:54:21,260 doesn't make a fuss about it at all. 785 00:54:21,260 --> 00:54:27,300 You can actually do extremely well out of not getting a Nobel Prize. 786 00:54:27,300 --> 00:54:31,300 I have had so many prizes and so many honours and so many awards, 787 00:54:31,300 --> 00:54:35,820 that I think I've had far more fun than if I'd got a Nobel Prize, 788 00:54:35,820 --> 00:54:40,140 which is a bit flash in the pan. You get it, you have a fun week, 789 00:54:40,140 --> 00:54:43,460 and it's all over and nobody gives you anything else after that 790 00:54:43,460 --> 00:54:46,820 because they feel they can't match it. 791 00:54:51,300 --> 00:54:52,620 For Jocelyn Bell Burnell, 792 00:54:52,620 --> 00:54:57,220 the real enemy of science is not the allocation, or otherwise, of prizes, 793 00:54:57,220 --> 00:55:01,860 it is the belief that science can arrive at an ultimate truth. 794 00:55:01,860 --> 00:55:06,820 There are people around, I think, 795 00:55:06,820 --> 00:55:11,420 who believe they have got there, believe they understand it all 796 00:55:13,980 --> 00:55:18,940 and they're no longer open to new experiences, 797 00:55:18,940 --> 00:55:21,980 new ideas, new revelations. 798 00:55:21,980 --> 00:55:25,020 I don't think you should be so closed. 799 00:55:27,260 --> 00:55:31,660 If we assume we've arrived, we stop searching. 800 00:55:33,660 --> 00:55:35,180 We stop developing. 801 00:55:39,860 --> 00:55:41,940 Professor Dame Jocelyn Bell Burnell 802 00:55:41,940 --> 00:55:44,820 has enjoyed a hugely successful career. 803 00:55:47,140 --> 00:55:50,820 She has gone from being "the girl who discovered pulsars" 804 00:55:50,820 --> 00:55:55,500 to recognition as one of the outstanding scientists of our time. 805 00:56:00,380 --> 00:56:04,100 Though she has played a significant part in our greater understanding 806 00:56:04,100 --> 00:56:09,380 of the Universe, she insists there is still some way to go in telling 807 00:56:09,380 --> 00:56:11,620 the complete story of the Cosmos. 808 00:56:13,980 --> 00:56:18,820 I can see a number of important issues facing astronomers today. 809 00:56:21,380 --> 00:56:25,700 There are questions about the future of the Universe. 810 00:56:25,700 --> 00:56:28,660 We believe we understand that the Universe started 811 00:56:28,660 --> 00:56:33,180 with what we call the Big Bang, 13, 14 billion years ago... 812 00:56:33,180 --> 00:56:36,180 and that it's been expanding ever since. 813 00:56:36,180 --> 00:56:39,980 One of the things we have recently discovered is that the expansion 814 00:56:39,980 --> 00:56:44,740 appears to be getting faster, which is totally counter-intuitive. 815 00:56:44,740 --> 00:56:48,380 You would expect the gravity between the galaxies to actually 816 00:56:48,380 --> 00:56:51,460 be slowing the expansion, and it's not, it's getting faster. 817 00:56:57,740 --> 00:57:01,100 Something is acting to oppose gravity. 818 00:57:01,100 --> 00:57:05,020 Something is pushing the galaxies apart, faster and faster 819 00:57:05,020 --> 00:57:08,460 and at the moment we have very little clue what that is. 820 00:57:08,460 --> 00:57:11,740 We call it dark energy, but that doesn't actually tell us 821 00:57:11,740 --> 00:57:14,100 what it is, it's just a label. 822 00:57:17,260 --> 00:57:22,660 It is hard to understand. I'm not sure how we're going to make progress 823 00:57:22,660 --> 00:57:27,300 on that one, but it's something that a lot of people are fascinated by. 824 00:57:31,260 --> 00:57:35,020 Looking at the Universe as a whole cosmology, the birth, life 825 00:57:35,020 --> 00:57:37,460 and death of the whole Universe... 826 00:57:37,460 --> 00:57:40,100 We used to have a nice, simple model. 827 00:57:40,100 --> 00:57:45,140 Then we added things like dark energy. And our nice, simple picture 828 00:57:45,140 --> 00:57:48,260 is getting messier and messier and messier. 829 00:57:54,940 --> 00:57:59,820 I have this sense that we need to picture cosmology, the evolution 830 00:57:59,820 --> 00:58:03,580 of the Universe, in a whole new way. 831 00:58:08,020 --> 00:58:11,380 I'm probably not one that can achieve this new thinking. 832 00:58:11,380 --> 00:58:16,740 Somebody will, and at the moment, we are waiting for it to happen. 833 00:58:16,740 --> 00:58:19,700 A bit like a pregnant pause. 834 00:58:21,540 --> 00:58:25,660 A bit like what happens when there's a snowfall, first snowfall 835 00:58:25,660 --> 00:58:30,260 of the year, and everything goes quiet, and kind of waits. 836 00:58:30,260 --> 00:58:32,700 I feel we're in that sort of phase. 837 00:58:36,780 --> 00:58:39,020 Nothing is static. 838 00:58:39,020 --> 00:58:40,660 Nothing is final. 839 00:58:49,860 --> 00:58:52,980 Subtitles by Red Bee Media Ltd 840 00:58:52,980 --> 00:58:56,780 E-mail subtitling@bbc.co.uk