0:00:06 > 0:00:10The 20th century witnessed an astonishing revolution in physics.
0:00:15 > 0:00:17From unlocking the secrets of the atom...
0:00:19 > 0:00:22..to working out the origins of the universe...
0:00:24 > 0:00:27..physics took us places we'd never dreamt possible.
0:00:33 > 0:00:36This was also a century when we were for the first time
0:00:36 > 0:00:40able to see and hear scientists in their own words.
0:00:41 > 0:00:45I began to notice there was something slightly curious on the records.
0:00:45 > 0:00:50I didn't take it in, because I was probably daydreaming, and...
0:00:50 > 0:00:54I can't stop! I mean, I could talk forever.
0:00:54 > 0:00:57So we began to learn not just about the science,
0:00:57 > 0:00:59but the men and women behind it.
0:01:01 > 0:01:03And the more we learnt about these scientists,
0:01:03 > 0:01:05the more it became clear
0:01:05 > 0:01:07that their personalities...
0:01:07 > 0:01:09eccentricities...
0:01:09 > 0:01:10and rivalries...
0:01:10 > 0:01:13It was that he was too sure too quickly.
0:01:13 > 0:01:16..were all fundamental to their discoveries.
0:01:17 > 0:01:20In fact, it's impossible truly to understand
0:01:20 > 0:01:22the 20th century revolution in physics
0:01:22 > 0:01:26without first knowing who these men and women really were.
0:01:26 > 0:01:29I see. And your idea is to find out what nature COULD be.
0:01:49 > 0:01:518:15am.
0:01:51 > 0:01:54The 6th August 1945.
0:01:54 > 0:01:55Hiroshima.
0:02:13 > 0:02:16And the world witnessed the power of physics.
0:02:20 > 0:02:22A catastrophic explosion
0:02:22 > 0:02:25sent a shock wave that flattened the city...
0:02:25 > 0:02:28sparked a huge firestorm
0:02:28 > 0:02:31and bathed every living thing in deadly radiation.
0:02:33 > 0:02:36Over 60,000 people died immediately.
0:02:38 > 0:02:40The atomic bomb shocked the world,
0:02:40 > 0:02:44causing a scale of destruction never before witnessed.
0:02:47 > 0:02:52It also broke the heart of the world's most famous scientist -
0:02:52 > 0:02:56the man who had launched the 20th century revolution in physics,
0:02:56 > 0:02:59and dedicated his life to world peace and equality.
0:03:32 > 0:03:34Hiroshima devastated Albert Einstein -
0:03:34 > 0:03:38not only because it tested his ideals,
0:03:38 > 0:03:40but also because he felt he had played a role
0:03:40 > 0:03:42in the development of the bomb.
0:03:46 > 0:03:49What weighed heaviest on Einstein's conscience
0:03:49 > 0:03:51was a letter he had signed in 1939.
0:03:53 > 0:03:56It was addressed to the US President, Roosevelt,
0:03:56 > 0:03:59and written to encourage the Americans to build the bomb
0:03:59 > 0:04:01to deter the Nazis.
0:04:03 > 0:04:05Einstein knew that his signature
0:04:05 > 0:04:08would have carried more weight than any other.
0:04:09 > 0:04:11After all, by then he was the most famous
0:04:11 > 0:04:15scientist in the world - a scientific superstar.
0:04:23 > 0:04:26Einstein never worked on the Manhattan Project
0:04:26 > 0:04:27that built the bomb,
0:04:27 > 0:04:29but from the moment he learnt about the death
0:04:29 > 0:04:32of tens of thousands of innocent civilians in Hiroshima,
0:04:32 > 0:04:35he deeply regretted ever having signed the letter.
0:04:41 > 0:04:43Yet there was also another, more fundamental way
0:04:43 > 0:04:47in which Hiroshima lay on Einstein's conscience.
0:04:47 > 0:04:49Because the equation that made him famous,
0:04:49 > 0:04:53the equation that symbolised the scientific revolution he created,
0:04:53 > 0:04:57was the very same equation that underpinned the atomic bomb -
0:04:57 > 0:04:59E = mc2.
0:05:26 > 0:05:29In this simple and beautiful equation,
0:05:29 > 0:05:31Einstein had rewritten the laws of physics.
0:05:33 > 0:05:36But he had also unwittingly handed the world
0:05:36 > 0:05:37the key to the atomic bomb.
0:05:39 > 0:05:42It was an outcome he could never have foreseen
0:05:42 > 0:05:46when he began his scientific studies at the start of the 20th century.
0:05:52 > 0:05:57Einstein had crafted E = mc2 when he was in his 20s.
0:05:58 > 0:06:02At the time, he was just a young man working in obscurity
0:06:02 > 0:06:04in a patent office in Bern, Switzerland.
0:06:06 > 0:06:10But he had a fascination for light, space and time.
0:06:10 > 0:06:13He read a lot while he was at the patent office.
0:06:13 > 0:06:15He read a lot in the evening and weekends,
0:06:15 > 0:06:19and there was an informal group of scientists in Bern.
0:06:19 > 0:06:22He was very much engaged in discussion about science,
0:06:22 > 0:06:27even though he was spending his time at work assessing patents.
0:06:29 > 0:06:34Despite the group, Einstein did his best work alone.
0:06:34 > 0:06:37His method was to create thought experiments
0:06:37 > 0:06:40that asked some simple, profound questions.
0:06:43 > 0:06:47Questions like, "If I'm travelling on a tram,
0:06:47 > 0:06:48"does time run differently for me
0:06:48 > 0:06:52"inside the tram compared to people standing on the street outside?"
0:06:55 > 0:06:59And, "If I was travelling away from a clock tower on a beam of light,
0:06:59 > 0:07:02"would my wristwatch and the clock read the same time?"
0:07:04 > 0:07:07Whichever area he was looking at,
0:07:07 > 0:07:10he would find the little inconsistencies,
0:07:10 > 0:07:12the things that didn't quite make sense,
0:07:12 > 0:07:15the things that in retrospect seem like a bit of a fudge
0:07:15 > 0:07:19when you got different explanations for the same phenomenon.
0:07:19 > 0:07:24And he would focus in on those little rough corners
0:07:24 > 0:07:26and completely cut them away and bring in something new,
0:07:26 > 0:07:28and bring clarity to the situation.
0:07:28 > 0:07:31And that was very characteristic, I think,
0:07:31 > 0:07:33of the way he operated in all those different fields.
0:07:35 > 0:07:39Einstein spent time deep in concentration
0:07:39 > 0:07:42considering the outcomes of his thought experiments...
0:07:43 > 0:07:46..which would culminate in two ground-breaking theories
0:07:46 > 0:07:49that would lay the foundations for modern physics.
0:07:52 > 0:07:55First there was his special theory of relativity.
0:07:57 > 0:08:00This proposed a radical new concept of space and time,
0:08:00 > 0:08:03suggesting that neither are absolutes,
0:08:03 > 0:08:05but can change depending on the relative motion
0:08:05 > 0:08:07of objects and observers.
0:08:09 > 0:08:12A set of ideas that also led to E = mc2.
0:08:16 > 0:08:19And then his general theory of relativity,
0:08:19 > 0:08:22which gave physicists a new understanding of gravity.
0:08:22 > 0:08:24Rather than being a force,
0:08:24 > 0:08:28it was now a property of the curvature of space and time.
0:08:28 > 0:08:30They were ground-breaking new theories,
0:08:30 > 0:08:33products of Einstein's vivid imagination, creativity
0:08:33 > 0:08:35and ambition.
0:08:38 > 0:08:40The freedom and independence he enjoyed in Bern,
0:08:40 > 0:08:44away from the formality of academia, allowed him the space
0:08:44 > 0:08:48to formulate some of the most original ideas in science.
0:08:49 > 0:08:53And as other scientists began to provide support for these theories,
0:08:53 > 0:08:56Einstein was rocketed into world fame.
0:08:56 > 0:09:01Einstein had the reputation, before all these results were announced,
0:09:01 > 0:09:04of being very mild-mannered, of being shy -
0:09:04 > 0:09:07but he absolutely rose to the occasion.
0:09:07 > 0:09:10He just basked in the glory, and he really loved it.
0:09:10 > 0:09:13And he went on tours and he talked to audiences.
0:09:13 > 0:09:16His lectures weren't always very good,
0:09:16 > 0:09:19and there's a report from Oxford by a student,
0:09:19 > 0:09:21and he said, when Professor Einstein came in,
0:09:21 > 0:09:26he was shuffling along and he looked quite dejected and low-spirited,
0:09:26 > 0:09:29and then the audience rose to its feet and clapped,
0:09:29 > 0:09:33and suddenly Einstein came alive and his whole face lit up -
0:09:33 > 0:09:36and he obviously really needed that public adulation.
0:09:36 > 0:09:38- MAN:- Can you kill the lights, fellas?
0:09:38 > 0:09:40Can you kill the lights?
0:09:42 > 0:09:43Shake hands with me...
0:09:46 > 0:09:49The public latched on to Einstein's playful image,
0:09:49 > 0:09:52rather than trying to understand his complicated theories.
0:09:54 > 0:09:57The intellectual elite treated him like a god.
0:10:13 > 0:10:14LAUGHTER
0:10:22 > 0:10:23After Einstein,
0:10:23 > 0:10:25the story of 20th-century physics
0:10:25 > 0:10:29became the story of men and women who either built on Einstein's work,
0:10:29 > 0:10:33attacked it, or filled in the gaps of what it could not explain.
0:10:35 > 0:10:38And the first big development after relativity
0:10:38 > 0:10:42concerned the one part of the universe that seemed to defy it.
0:10:42 > 0:10:44The world of the subatomic particle.
0:10:47 > 0:10:49This was a strange new world,
0:10:49 > 0:10:53and it led to an entirely new branch of physics.
0:11:00 > 0:11:02It was called quantum theory,
0:11:02 > 0:11:06and became characterised by both bizarre ideas
0:11:06 > 0:11:07and rather bizarre people.
0:11:14 > 0:11:19Few were more strange than British mathematician Paul Dirac.
0:11:19 > 0:11:21His intellect rivalled that of Albert Einstein,
0:11:21 > 0:11:25but in character Dirac could not have been more different.
0:11:28 > 0:11:31Talking about the history of quantum mechanics,
0:11:31 > 0:11:33the English physicist Paul Dirac.
0:11:34 > 0:11:40Quantum mechanics was discovered 40 years ago by Heisenberg.
0:11:41 > 0:11:45Shortly afterwards it was discovered again,
0:11:45 > 0:11:49independently, in a rather different form by Schrodinger.
0:11:51 > 0:11:56Heisenberg and Schrodinger gave us a very wonderful theory.
0:11:56 > 0:12:02Many people took it up and proceeded to develop it.
0:12:02 > 0:12:03I was one of them.
0:12:03 > 0:12:07Well, he was certainly a very strange man.
0:12:07 > 0:12:10He was very quiet - people call him shy.
0:12:10 > 0:12:12I guess he was shy.
0:12:12 > 0:12:14He took things very literally.
0:12:14 > 0:12:17Also, it might be something that seemed a bit rude.
0:12:17 > 0:12:20I know that somebody asked him
0:12:20 > 0:12:22whether he had seen any good films recently, or something -
0:12:22 > 0:12:24sitting next to him, probably, at High Table,
0:12:24 > 0:12:27at St John's College, Cambridge,
0:12:27 > 0:12:29and he said, "Well, why do you want to know?"
0:12:31 > 0:12:33Dirac would later attribute his silence
0:12:33 > 0:12:36to being bullied as a child by his father.
0:12:37 > 0:12:40he was brought up by this very strict father
0:12:40 > 0:12:43who insisted that at dinner time - or at home, I think -
0:12:43 > 0:12:46his son should only speak in French.
0:12:46 > 0:12:49And Dirac didn't like to speak in French,
0:12:49 > 0:12:53and so, the preferable option, he just didn't speak at all.
0:12:55 > 0:12:58Others claimed Dirac's social awkwardness
0:12:58 > 0:12:59was because he was autistic.
0:12:59 > 0:13:01Whatever the reason,
0:13:01 > 0:13:03it didn't hold him back in the pursuit of a career
0:13:03 > 0:13:05in mathematics at Cambridge.
0:13:08 > 0:13:11Professor Dirac, we heard before from Professor Heisenberg
0:13:11 > 0:13:14about his visit to the Kapitza Club in Cambridge.
0:13:14 > 0:13:16Can you tell us something about that club?
0:13:16 > 0:13:20Kapitza was a young Russian physicist who came to Cambridge
0:13:20 > 0:13:22to work with Rutherford.
0:13:23 > 0:13:26He organised a club, about 20 members, physicists,
0:13:26 > 0:13:30who would meet every Tuesday evening,
0:13:30 > 0:13:34and someone would then read a paper on some question of physics,
0:13:34 > 0:13:37and there would be a lot of discussion afterwards.
0:13:37 > 0:13:39There was a minute book that was kept of this club,
0:13:39 > 0:13:42which is very fortunate, and we can look in the records of that
0:13:42 > 0:13:45and see just the subject that Heisenberg talked on.
0:13:46 > 0:13:50I don't remember whether he spoke about his new theory at that time.
0:13:50 > 0:13:55I... If he did, I didn't take it in, because...
0:13:55 > 0:13:57I was probably daydreaming,
0:13:57 > 0:14:00and I don't take in everything a lecturer says.
0:14:01 > 0:14:03Despite his daydreaming,
0:14:03 > 0:14:06Dirac was singled out as a brilliant and fresh new talent
0:14:06 > 0:14:08in the new field of quantum theory.
0:14:10 > 0:14:12He was invited to speak
0:14:12 > 0:14:14at the most prestigious international physics event -
0:14:14 > 0:14:16the Solvay Conference.
0:14:19 > 0:14:22Only a few months later, he published an equation
0:14:22 > 0:14:24which would solve one of the biggest problems in physics
0:14:24 > 0:14:26and become his most seminal work.
0:14:28 > 0:14:31I suppose the thing that Dirac's best known for
0:14:31 > 0:14:33is the Dirac equation.
0:14:33 > 0:14:36And I remember going to lectures where people would say,
0:14:36 > 0:14:37"Well, the Dirac equation
0:14:37 > 0:14:40"is the most accurate equation known in science."
0:14:40 > 0:14:42I don't know if you'd say that now,
0:14:42 > 0:14:45but it's the equation of the electron.
0:14:47 > 0:14:50It was partly to solve a problem which people found
0:14:50 > 0:14:52that they couldn't describe particles
0:14:52 > 0:14:54in accordance with relativity.
0:15:00 > 0:15:02Dirac had done what no-one else could.
0:15:04 > 0:15:08He had crafted an equation to describe how electrons behave
0:15:08 > 0:15:10that was consistent with both quantum theory
0:15:10 > 0:15:12and special relativity.
0:15:14 > 0:15:16A union that had yet to be proved possible.
0:15:18 > 0:15:21It was certainly highly original,
0:15:21 > 0:15:24but I think this was driven, maybe,
0:15:24 > 0:15:28by the fact that there was a barrier between him and the outside world,
0:15:28 > 0:15:30and that he was internally driven
0:15:30 > 0:15:35and therefore found that this was the way he understood things,
0:15:35 > 0:15:38and he would quite often, therefore, understand things in a different way
0:15:38 > 0:15:41from the way other people did, and it might be a better way,
0:15:41 > 0:15:43because he'd thought it all through in his own terms.
0:15:49 > 0:15:52As well as explaining how electrons behave,
0:15:52 > 0:15:56he developed a theory of quantum electrodynamics
0:15:56 > 0:15:59which described the interactions between electrons and light.
0:16:02 > 0:16:06Dirac's unique understanding of subatomic particles
0:16:06 > 0:16:08won him a Nobel prize
0:16:08 > 0:16:11and led to a series of breakthroughs in quantum physics.
0:16:13 > 0:16:15But despite all of his successes,
0:16:15 > 0:16:18Dirac would never become a household name.
0:16:18 > 0:16:21Unlike Einstein, attention made him uncomfortable,
0:16:21 > 0:16:24so he avoided the limelight whenever he could.
0:16:24 > 0:16:28He was interested in other things than science,
0:16:28 > 0:16:29but a little bit surprising -
0:16:29 > 0:16:31for instance he was interested in cartoon movies,
0:16:31 > 0:16:33Mickey Mouse, and things like that.
0:16:33 > 0:16:35He was interested in things
0:16:35 > 0:16:39where the emotional content was not a major part of it.
0:16:39 > 0:16:41But then there was also this story about either a play or a book,
0:16:41 > 0:16:43I can't quite remember which now,
0:16:43 > 0:16:45by a Russian author - maybe Dostoevsky.
0:16:45 > 0:16:49In it, somebody asks him, "Well, what did you make of it?
0:16:49 > 0:16:51"Did you enjoy it?"
0:16:51 > 0:16:55And he said, "Well, at one point the author made a mistake
0:16:55 > 0:16:59"and he said the sun rose twice in the same day."
0:16:59 > 0:17:00HE CHUCKLES
0:17:00 > 0:17:02So this is the sort of thing he would point out
0:17:02 > 0:17:06about some literary classic,
0:17:06 > 0:17:11rather than commenting on its emotional impact.
0:17:17 > 0:17:20Dirac only ever let a few people into his world.
0:17:23 > 0:17:29His wife was the sister of a very distinguish quantum physicist -
0:17:29 > 0:17:32or a mathematical physicist, Eugene Wigner,
0:17:32 > 0:17:34who was a very important figure, also, in the early days
0:17:34 > 0:17:36of quantum mechanics,
0:17:36 > 0:17:39and so she must have known that community
0:17:39 > 0:17:43and known how Dirac was respected within that community,
0:17:43 > 0:17:47which I expect had something to do with their getting together.
0:17:47 > 0:17:50And she probably felt that he was somebody who needed protection,
0:17:50 > 0:17:52needed attention,
0:17:52 > 0:17:55and somebody who would be very worthwhile
0:17:55 > 0:17:58and interesting to be with.
0:18:11 > 0:18:15While Dirac was developing the foundations of quantum mechanics,
0:18:15 > 0:18:18explaining the world of the very small,
0:18:18 > 0:18:20other scientists were working at the opposite scale,
0:18:20 > 0:18:23exploring the boundaries of the known universe.
0:18:25 > 0:18:27General relativity had led to the idea
0:18:27 > 0:18:30that we live in an expanding universe,
0:18:30 > 0:18:32and observations had confirmed it.
0:18:35 > 0:18:37But this led to a fundamental question.
0:18:38 > 0:18:41Did the universe have a beginning?
0:18:45 > 0:18:47It was a question that would cause
0:18:47 > 0:18:51one of the bitterest rivalries in science -
0:18:51 > 0:18:54a conflict that consumed two brilliant physicists,
0:18:54 > 0:18:56but would ultimately lead us
0:18:56 > 0:18:59to a deeper understanding of the universe.
0:19:02 > 0:19:06As you probably know, there are two forms of cosmology -
0:19:06 > 0:19:10what has been spoken of as the Big Bang, and the Steady State.
0:19:10 > 0:19:12The one that I've been associated with...
0:19:14 > 0:19:17..the galaxies must be forming the whole time.
0:19:18 > 0:19:21Fred Hoyle was the son of a wool merchant,
0:19:21 > 0:19:22and brusque Yorkshireman,
0:19:22 > 0:19:26who believed that the universe had no beginning and has no end.
0:19:31 > 0:19:34In the explosion theory,
0:19:34 > 0:19:36we suppose that the matter
0:19:36 > 0:19:39in the universe was originally in a highly condensed state
0:19:39 > 0:19:41which then expanded.
0:19:41 > 0:19:46And the galaxies which we now see are fragments of this explosion.
0:19:48 > 0:19:51Martin Ryle was a volatile yet sensitive man
0:19:51 > 0:19:55who, unlike Hoyle, believed the universe did have a beginning.
0:19:59 > 0:20:01Both worked at Cambridge University.
0:20:01 > 0:20:04And in the 1950s, neither man had enough evidence to prove
0:20:04 > 0:20:07one way or the other who was right.
0:20:11 > 0:20:15- PROFESSOR MARTIN REES:- I only got to know Fred Hoyle after 1965,
0:20:15 > 0:20:16when I was a student,
0:20:16 > 0:20:19but I already became aware that he had been a great figure
0:20:19 > 0:20:22in the history of the subject.
0:20:22 > 0:20:26Indeed between 1945 and 1965 it's fair to say that he contributed more
0:20:26 > 0:20:31to astronomy on the theoretical side than anyone else in the world.
0:20:31 > 0:20:34He was an extraordinarily inventive and versatile person.
0:20:34 > 0:20:39And his greatest achievement, in retrospect, was to realise
0:20:39 > 0:20:44that all the atoms that we are made of were forged inside stars.
0:20:47 > 0:20:50Hoyle was a confident man whose great achievements were,
0:20:50 > 0:20:53in part, because he wasn't afraid to go it alone
0:20:55 > 0:20:58FRED HOYLE: One of the things that one has to, um, think about
0:20:58 > 0:21:02is you have to have a sense of obstinacy in science.
0:21:02 > 0:21:08Because if you don't, you're not going to go against the crowd.
0:21:08 > 0:21:09And if you don't go against the crowd,
0:21:09 > 0:21:11you're not going to have any real successes.
0:21:11 > 0:21:18But the question then is, can it interfere with one's judgment?
0:21:18 > 0:21:21Well, um, let me make it absolutely clear
0:21:21 > 0:21:24that a sense of obstinacy is only of value
0:21:24 > 0:21:29insofar as it allows you to discount the opinions of other humans.
0:21:30 > 0:21:32At the time, Hoyle was an atheist.
0:21:32 > 0:21:34So perhaps it wasn't surprising
0:21:34 > 0:21:38that his Steady State theory avoided any hint of a genesis.
0:21:40 > 0:21:43He said that the universe had always looked the same,
0:21:43 > 0:21:45that new galaxies formed
0:21:45 > 0:21:49in the spaces made by the universe's expansion.
0:21:53 > 0:21:55And as a practised populariser of science,
0:21:55 > 0:21:59Hoyle took to the airwaves to promote his point of view.
0:21:59 > 0:22:01The BBC presents The Nature Of The Universe.
0:22:01 > 0:22:04'The speaker is Fred Hoyle -
0:22:04 > 0:22:07'a Cambridge mathematician and Fellow of St John's College.'
0:22:07 > 0:22:10'Perhaps like me, you grew up with a notion
0:22:10 > 0:22:13'that the whole of the matter in the universe
0:22:13 > 0:22:18'was created in one big bang at a particular time in the remote past.
0:22:18 > 0:22:21'What I'm now going to tell you is that this is wrong.'
0:22:21 > 0:22:25EXPLOSION
0:22:25 > 0:22:28Hoyle was the first person to refer to the explosion theory
0:22:28 > 0:22:30as a "big bang".
0:22:30 > 0:22:31EXPLOSIVE RUMBLING
0:22:31 > 0:22:34And although he didn't intend it to, the phrase
0:22:34 > 0:22:36captured the public's imagination
0:22:36 > 0:22:38and became a brilliant marketing tool for his opponents.
0:22:44 > 0:22:47Perhaps his greatest opponent was Ryle -
0:22:47 > 0:22:48different in almost every way.
0:22:51 > 0:22:55Unlike Hoyle he was a practical scientist, an engineer,
0:22:55 > 0:22:58who sought to observe the secrets of the universe,
0:22:58 > 0:23:02mapping the faintest, furthest things in the universe
0:23:02 > 0:23:03with a radio telescope -
0:23:03 > 0:23:06the newest and most exciting instrument in astronomy.
0:23:09 > 0:23:11MUSIC: Raymond Baxter Reports Theme
0:23:16 > 0:23:20- RAYMOND BAXTER:- 'This is Martin Ryle, Fellow of The Royal Society,
0:23:20 > 0:23:24'Professor of Radio Astronomy at Cambridge University.'
0:23:24 > 0:23:27'We're receiving a naturally emitted radiation,
0:23:27 > 0:23:28'just like the light from a star.'
0:23:28 > 0:23:31And if we listen to these radio waves,
0:23:31 > 0:23:34as in the case of the distant source, in Cygnus,
0:23:34 > 0:23:36what we hear is a rushing noise.
0:23:37 > 0:23:41WHOOSHING
0:23:41 > 0:23:44- PROFESSOR REES:- Martin Ryle was above all a brilliant technician
0:23:44 > 0:23:46and engineer, but also he combined that
0:23:46 > 0:23:51with being someone who understood the theory of what he was doing
0:23:51 > 0:23:52and the importance of it.
0:23:52 > 0:23:55And it's important to realise
0:23:55 > 0:23:58that having invested many years of effort
0:23:58 > 0:24:02in developing a pioneering new telescope,
0:24:02 > 0:24:03and actually built it
0:24:03 > 0:24:06and made the effort to get the money for it et cetera,
0:24:06 > 0:24:09then, clearly, he had a huge stake
0:24:09 > 0:24:12in ensuring that it did important work
0:24:12 > 0:24:17and was naturally rather sensitive at criticism of the output.
0:24:19 > 0:24:22So when theorist Fred Hoyle publically questioned the accuracy
0:24:22 > 0:24:25of the first data set produced by his telescope,
0:24:25 > 0:24:28Ryle was devastated.
0:24:28 > 0:24:30I think he took criticism rather deeply.
0:24:30 > 0:24:33It's partly because of his personality.
0:24:33 > 0:24:36Unlike Fred Hoyle, he was not robust in argument -
0:24:36 > 0:24:37he got genuinely upset -
0:24:37 > 0:24:40and he didn't really like taking part in debate.
0:24:40 > 0:24:43He didn't go to many conferences - he didn't enjoy them.
0:24:43 > 0:24:48And so he therefore took very deeply any criticism -
0:24:48 > 0:24:49it meant a lot to him.
0:24:49 > 0:24:52In front of the media,
0:24:52 > 0:24:55Ryle was very self-controlled and diplomatic.
0:24:55 > 0:24:59But those who knew him well often saw a different side to him.
0:24:59 > 0:25:01PROFESSOR CRAIG MACKAY: Martin Ryle did have
0:25:01 > 0:25:02a bit of a temper, there's no doubt about it.
0:25:02 > 0:25:05He would very easily fly into a rage about something.
0:25:05 > 0:25:07And I ended up getting on extremely
0:25:07 > 0:25:09well with him by writing down
0:25:09 > 0:25:12what my argument was and giving it to him.
0:25:12 > 0:25:15I would then get that back after a day or two,
0:25:15 > 0:25:17with Biro markings which were often
0:25:17 > 0:25:20so fierce as to go right through the paper.
0:25:20 > 0:25:23And that would be his view of the whole thing and I would reply.
0:25:23 > 0:25:24So we had this correspondence
0:25:24 > 0:25:27and it's my great regret that I've kept none of that.
0:25:27 > 0:25:29Many of those bits of paper were pretty transparent
0:25:29 > 0:25:30after he'd had a go at them.
0:25:33 > 0:25:36Ryle's fury with Hoyle fuelled his determination
0:25:36 > 0:25:41to use his radio telescope to destroy the Steady State theory.
0:25:43 > 0:25:46Can you explain exactly what you've been doing?
0:25:46 > 0:25:48Well, I think we'd better have a diagram here.
0:25:48 > 0:25:50And perhaps we could look at the board.
0:25:53 > 0:25:55According to the theory of continuous creation,
0:25:55 > 0:25:58the density of galaxies would be the same
0:25:58 > 0:26:02in the neighbourhood of the Earth, here,
0:26:02 > 0:26:05right out to the edges of the observable universe.
0:26:07 > 0:26:13One way in which one could test the two theories is to make a measurement
0:26:13 > 0:26:15of the variation of the density of
0:26:15 > 0:26:16galaxies with distance from us.
0:26:17 > 0:26:21If the Steady State theory was right then the more distant galaxies,
0:26:21 > 0:26:25which are older, would be distributed just as they are now,
0:26:25 > 0:26:28because it says the universe has always been the same.
0:26:31 > 0:26:32EXPLOSION
0:26:32 > 0:26:34If the Big Bang theory was right,
0:26:34 > 0:26:36then the more distant galaxies
0:26:36 > 0:26:38would be more densely packed,
0:26:38 > 0:26:41because the early universe would have been crammed full of matter
0:26:41 > 0:26:44before expanding and evolving.
0:26:44 > 0:26:47It's very easy for someone in the public to look at this
0:26:47 > 0:26:50and think, "It's two astronomers arguing about something."
0:26:50 > 0:26:52They're not. They're very different.
0:26:52 > 0:26:55A mathematician and an engineer are really rather different animals,
0:26:55 > 0:26:58they do look at the universe in a completely different way,
0:26:58 > 0:27:01they see different things - that was the fundamental problem, I think.
0:27:01 > 0:27:03There was very little attempt on either side,
0:27:03 > 0:27:05I believe, to understand the other -
0:27:05 > 0:27:08how they worked, how they ticked.
0:27:08 > 0:27:11Unlike Ryle, Hoyle was a performer
0:27:11 > 0:27:14and wasn't one to keep his opinions to himself.
0:27:14 > 0:27:16Do you reject this Big Bang theory?
0:27:16 > 0:27:19This concept of a beginning, an evolution and a going on?
0:27:19 > 0:27:23Well, I do and I always have done.
0:27:23 > 0:27:28One doesn't impress on the universe its properties in the start.
0:27:28 > 0:27:32I think my objection to Ryle was he was too sure too quickly.
0:27:34 > 0:27:37- PROFESSOR MACKAY:- Martin Ryle also found it very difficult
0:27:37 > 0:27:38with Fred Hoyle being
0:27:38 > 0:27:40extremely negative about the work of the group,
0:27:40 > 0:27:43but it's also true that Martin Ryle really made
0:27:43 > 0:27:47no serious attempt to build bridges with Hoyle and his people.
0:27:47 > 0:27:50And I think that that was very unfortunate.
0:27:50 > 0:27:53The two groups were working maybe as far as 200yds apart
0:27:53 > 0:27:57in the same town - an easy walk from one to the other -
0:27:57 > 0:27:59and the contact between the two groups was minimal.
0:27:59 > 0:28:04Collecting radio telescope data was a slow process.
0:28:04 > 0:28:08But in 1961, Martin Ryle presented a comprehensive catalogue
0:28:08 > 0:28:11that showed the furthest observable galaxies
0:28:11 > 0:28:14were more densely distributed.
0:28:14 > 0:28:16Finally he could settle the matter.
0:28:16 > 0:28:19RYLE ON TAPE: 'The first and most remarkable result of all,
0:28:19 > 0:28:20'as you proceed outwards
0:28:20 > 0:28:21'from the most intense
0:28:21 > 0:28:23'and presumably nearest sources,
0:28:23 > 0:28:26'we find a great excess of fainter ones.
0:28:27 > 0:28:30'The universe must have changed radically within the time span
0:28:30 > 0:28:32'accessible to our radio telescopes.
0:28:32 > 0:28:37'This result seems to show quite clearly that the Steady State -
0:28:37 > 0:28:38'the continuous creation -
0:28:38 > 0:28:41'theory of the universe cannot be correct.
0:28:42 > 0:28:45'The results imply that the universe is changing with time.'
0:28:46 > 0:28:50The rivalry between these two men had finally yielded a result -
0:28:50 > 0:28:54evidence for the Big Bang theory.
0:28:54 > 0:28:56Most of it comes from a body much larger...
0:28:56 > 0:28:58For most astronomers, the proof was now stacked against
0:28:58 > 0:29:00Hoyle and his theory.
0:29:00 > 0:29:03Although Hoyle himself wouldn't accept it.
0:29:04 > 0:29:06You have here in Cambridge Professor Ryle,
0:29:06 > 0:29:09who is a radio astronomer and, as I understand it,
0:29:09 > 0:29:13he made a study of the radio stars and claims to have proved
0:29:13 > 0:29:15your Steady State theory wrong.
0:29:15 > 0:29:17I still take the same view today.
0:29:17 > 0:29:20I think we cannot know whether there is a contradiction with the theory
0:29:20 > 0:29:24until we know exactly what these radio sources are.
0:29:26 > 0:29:27BIRDSONG
0:29:33 > 0:29:35Even when the rest of the scientific community
0:29:35 > 0:29:37embraced the Big Bang theory,
0:29:37 > 0:29:39Hoyle refused to join them.
0:29:44 > 0:29:48In the early 1970s, Hoyle felt forced out of Cambridge.
0:29:50 > 0:29:53He moved to the Cumbrian countryside,
0:29:53 > 0:29:57where he pursued his love for science fiction writing.
0:29:57 > 0:29:59Tea's ready.
0:30:00 > 0:30:04Here, he also had more time to spend with friends.
0:30:06 > 0:30:08Including a man who was revolutionising
0:30:08 > 0:30:11the other great branch of 20th-century physics -
0:30:11 > 0:30:14the quantum world of subatomic particles.
0:30:17 > 0:30:19Despite their very different specialisms,
0:30:19 > 0:30:21they found they had a lot in common.
0:30:21 > 0:30:25'Have you had a moment in a complicated problem,'
0:30:25 > 0:30:27where quite suddenly the thing comes into your head
0:30:27 > 0:30:29and you're almost sure you've got to be right?
0:30:29 > 0:30:31Oh, yes. That's...
0:30:31 > 0:30:33- This is great.- Oh, God, yeah.
0:30:33 > 0:30:35Richard Feynman was the ultimate showman,
0:30:35 > 0:30:38an American who became everybody's favourite physicist.
0:30:38 > 0:30:42# In a spell That old black magic
0:30:42 > 0:30:43# That you weave so well... #
0:30:43 > 0:30:45He was a brilliant mathematician...
0:30:47 > 0:30:48enamoured by the smallest,
0:30:48 > 0:30:51most fundamental building blocks of the universe.
0:30:51 > 0:30:53# ..Always glad when your eyes meet mine
0:30:53 > 0:30:57# That same old tingle That I feel inside... #
0:30:57 > 0:31:02Suppose little things behave very differently
0:31:02 > 0:31:05than ANYTHING that was big.
0:31:05 > 0:31:08The behaviour of things on a small scale is so fantastic,
0:31:08 > 0:31:13it's so wonderfully...different.
0:31:13 > 0:31:16I get a kick out of thinking...
0:31:16 > 0:31:18about these things.
0:31:18 > 0:31:22Uh, I can't stop. I mean, I could talk for ever.
0:31:22 > 0:31:27He was charismatic, engaging and enthusiastic.
0:31:27 > 0:31:30A bongo-playing prankster who approached both life
0:31:30 > 0:31:32and science with a sense of playfulness.
0:31:33 > 0:31:36Atoms do not behave like weights hanging on a spring
0:31:36 > 0:31:37and oscillating,
0:31:37 > 0:31:40nor do they behave like miniature representations
0:31:40 > 0:31:43of the solar system with little planets going around in orbit.
0:31:43 > 0:31:45It behaves like nothing
0:31:45 > 0:31:47that you've seen before.
0:31:48 > 0:31:50Well, there's one simplification.
0:31:50 > 0:31:51At least electrons behave
0:31:51 > 0:31:55exactly the same in this respect as photons,
0:31:55 > 0:31:58that is they are both screwy - but in exactly the same way.
0:32:00 > 0:32:04As a quantum man, Feynman was inspired by the great Paul Dirac.
0:32:04 > 0:32:07PROFESSOR ROGER PENROSE: There's this wonderful picture
0:32:07 > 0:32:09at the Warsaw conference of Feynman talking to Dirac -
0:32:09 > 0:32:13Dirac leaning back and Feynman being very...
0:32:13 > 0:32:16very demonstrative. They were very different characters,
0:32:16 > 0:32:18completely different characters.
0:32:18 > 0:32:20Dirac being this introverted...
0:32:20 > 0:32:22afraid to say things
0:32:22 > 0:32:24unless they're absolutely right.
0:32:24 > 0:32:26Feynman saying anything that comes to his mind -
0:32:26 > 0:32:28they usually were right nevertheless.
0:32:33 > 0:32:35Despite the differences in their characters,
0:32:35 > 0:32:38they were both fascinated by the same things.
0:32:38 > 0:32:41In fact Feynman was especially interested in unlocking
0:32:41 > 0:32:43a riddle that lay at heart of
0:32:43 > 0:32:47Dirac's own work on quantum electrodynamics.
0:32:47 > 0:32:49I read Dirac's book and he had these
0:32:49 > 0:32:52problems that nobody knew how to solve that were described there.
0:32:52 > 0:32:56I couldn't understand the book very well because I wasn't up to it.
0:32:56 > 0:32:58But there in the last paragraph
0:32:58 > 0:33:00at the end of the book it said,
0:33:00 > 0:33:02"Some new ideas are here needed."
0:33:02 > 0:33:05And so there I was, "Some new ideas are needed? OK."
0:33:05 > 0:33:07So I started to think of new ideas.
0:33:11 > 0:33:13Although Dirac's mathematical description
0:33:13 > 0:33:15of how electrons and photons interact
0:33:15 > 0:33:18was undeniably correct, the equations themselves
0:33:18 > 0:33:20confused physicists
0:33:20 > 0:33:24because they sometimes produced crazy answers like infinity.
0:33:26 > 0:33:28PROFESSOR PENROSE: Feynman went his own route
0:33:28 > 0:33:31and he said, "Look we don't have to have all this complicated stuff,
0:33:31 > 0:33:34"all these formulas and fancy mathematics.
0:33:34 > 0:33:37"Let's get right down to the root of what we're trying to do."
0:33:38 > 0:33:42Feynman's confidence, creativity and direct approach led to
0:33:42 > 0:33:44a radical solution to Dirac's riddle.
0:33:46 > 0:33:49It's like building those houses of cards,
0:33:49 > 0:33:51and each of the cards is shaky.
0:33:51 > 0:33:53If you forget one of them,
0:33:53 > 0:33:57the whole thing collapses again. and you have to build them up again.
0:33:58 > 0:34:02Feynman's answer came in the form of diagrams.
0:34:05 > 0:34:09Little pictures that represented each step of the equations.
0:34:10 > 0:34:12They could be manipulated,
0:34:12 > 0:34:15used to simplify the complicated calculations, remove the infinities,
0:34:15 > 0:34:18and produce useful answers
0:34:18 > 0:34:21to make accurate predictions about the world.
0:34:22 > 0:34:27Physicists all over the world started using the diagrams.
0:34:27 > 0:34:30Feynman had unlocked the potential of Dirac's electrodynamics.
0:34:33 > 0:34:36FANFARE PLAYS
0:34:39 > 0:34:44In 1965, Feynman was given the Nobel prize to recognise the impact
0:34:44 > 0:34:48of his diagrams, although he wasn't the most grateful receiver of it.
0:34:52 > 0:34:53I don't like honours.
0:34:55 > 0:34:58I'm appreciated for the work that I did
0:34:58 > 0:34:59and the people who appreciate it,
0:34:59 > 0:35:02and I notice that other physicists use my work.
0:35:02 > 0:35:03I don't NEED anything else,
0:35:03 > 0:35:07I don't think there's any sense to anything else.
0:35:07 > 0:35:11I don't see that it makes any point that someone in the Swedish Academy
0:35:11 > 0:35:15decides that this work is noble enough to receive a prize.
0:35:15 > 0:35:16I've already got the prize,
0:35:16 > 0:35:19the prize is the pleasure of finding the thing out,
0:35:19 > 0:35:21the kick in the discovery,
0:35:21 > 0:35:24the observation that other people use it.
0:35:24 > 0:35:27Those are the REAL things.
0:35:27 > 0:35:30The honours are unreal to me.
0:35:31 > 0:35:33For Feynman, the real reward
0:35:33 > 0:35:35was communicating his passion
0:35:35 > 0:35:37to others, and he was very good at it.
0:35:38 > 0:35:40The things that are solid are made of atoms,
0:35:40 > 0:35:43which, although they're jiggling, they never get out of place.
0:35:43 > 0:35:46If you took one away, the others in the right place pull them back.
0:35:46 > 0:35:48You see, it's a perpetual...
0:35:48 > 0:35:50check with your friend. "Are you OK?" "Yes."
0:35:50 > 0:35:53It's like people marching in a...
0:35:53 > 0:35:56It's like the high school band march, OK?
0:35:56 > 0:35:58Nobody really knows what they're doing.
0:35:58 > 0:36:00They're going like this. It's OK, it holds together.
0:36:00 > 0:36:05Students flocked to his lectures and would seek out his company
0:36:05 > 0:36:06whenever they could.
0:36:06 > 0:36:09I don't want to take this stuff seriously, I think
0:36:09 > 0:36:13we should have fun imagining it and not worry about it.
0:36:13 > 0:36:16There's no teacher going to ask you questions at the end.
0:36:16 > 0:36:18Otherwise it's a horrible subject.
0:36:18 > 0:36:20# You gotta have my... #
0:36:20 > 0:36:22Feynman's informal approach to science,
0:36:22 > 0:36:25and his brilliant creativity, were instrumental in the development
0:36:25 > 0:36:29and accessibility of quantum theory in the late-20th century.
0:36:29 > 0:36:30YELLS
0:36:30 > 0:36:33MUSIC: Spinning Wheel by Blood Sweat & Tears
0:36:42 > 0:36:45At the same time as the revolution in quantum physics,
0:36:45 > 0:36:49scientists were also making great astronomical finds.
0:36:49 > 0:36:53Observations that would provide robust proof of Einstein's theories.
0:36:57 > 0:37:00One the most significant discoveries was made in the late '60s,
0:37:00 > 0:37:02by an extremely determined young woman
0:37:02 > 0:37:06embarking on a career in the field of radio astronomy.
0:37:08 > 0:37:11'The new instrument was perhaps the least glamorous telescope
0:37:11 > 0:37:16'ever built and it was to be operated full-time by one person,
0:37:16 > 0:37:17'a girl.'
0:37:20 > 0:37:24Jocelyn Bell Burnell however was not just a girl, she was
0:37:24 > 0:37:28a talented scientist who had a lifelong passion for the night sky.
0:37:32 > 0:37:35JOCELYN: I went away to boarding school at 13.
0:37:36 > 0:37:39My physics teacher that I had, Mr Tillet, was a super teacher.
0:37:39 > 0:37:43I could well have had a physics teacher
0:37:43 > 0:37:45who took the view that girls couldn't do physics
0:37:45 > 0:37:47and what's the point of trying kind of thing.
0:37:47 > 0:37:51I'm not sure where I'd have gone then, what I'd have done
0:37:51 > 0:37:53but Mr Tillet was quite the opposite.
0:37:55 > 0:37:58I went to Glasgow and I was the only woman doing physics
0:37:58 > 0:38:02and every time I entered the lecture theatre, as was the tradition,
0:38:02 > 0:38:03the guys whistled,
0:38:03 > 0:38:06stamped, catcalled, banged their desks.
0:38:06 > 0:38:09There was a them and me.
0:38:10 > 0:38:13I was rather on my own the whole time.
0:38:14 > 0:38:17MUSIC: Come On Everybody by Eddie Cochran
0:38:25 > 0:38:30In the early 1960s, Bell Burnell started her PhD as part
0:38:30 > 0:38:33of Martin Ryle's radio astronomy group at Cambridge University.
0:38:36 > 0:38:38She had found her spiritual home.
0:38:42 > 0:38:44It was here that Mr Tillet's inspirational teaching
0:38:44 > 0:38:49and Glasgow University's trial by ordeal would start to bear fruit.
0:38:55 > 0:38:59The Cambridge Radio Astronomy Group had an interest in distant objects
0:38:59 > 0:39:02because they were interested in general
0:39:02 > 0:39:04in how the universe had evolved.
0:39:04 > 0:39:07But first we had to build the radio telescope, and actually
0:39:07 > 0:39:12I spent two of my three years constructing a radio telescope.
0:39:12 > 0:39:14She was outside in this muddy field,
0:39:14 > 0:39:18literally building things that looked like a very large fence,
0:39:18 > 0:39:20with wooden poles and wires strung between them,
0:39:20 > 0:39:22and it was quite a hard business.
0:39:22 > 0:39:25I think she must have become very, very fit because of all that,
0:39:25 > 0:39:28but it was a difficult, physically demanding life that she led
0:39:28 > 0:39:31when the telescope was being built.
0:39:31 > 0:39:34But it was only once the last cables were connected
0:39:34 > 0:39:36that the real work started.
0:39:37 > 0:39:39Bell Burnell was in charge of searching
0:39:39 > 0:39:42for tiny bright objects far out in the cosmos.
0:39:43 > 0:39:46We were actually using this telescope to look for quasars,
0:39:46 > 0:39:50because they twinkle, and this thing is specially designed to pick out
0:39:50 > 0:39:52twinkling things.
0:39:52 > 0:39:56And after we'd been running I suppose about a few months
0:39:56 > 0:39:59I began to notice there was something slightly curious on the records.
0:39:59 > 0:40:02They came out as paper charts,
0:40:02 > 0:40:05and of course on these charts you could see radio sources
0:40:05 > 0:40:09and unfortunately you could also see man-made interference.
0:40:09 > 0:40:12But there was also something that didn't quite fit either bill -
0:40:12 > 0:40:15it wasn't exactly a twinkling radio source
0:40:15 > 0:40:18and it wasn't exactly interference either.
0:40:27 > 0:40:31Everybody's first reactions were that it must be man-made.
0:40:32 > 0:40:35Including Bell Burnell's supervisor Antony Hewish,
0:40:35 > 0:40:38who was convinced there had to be a terrestrial explanation
0:40:38 > 0:40:41for the anomaly on the paper chart.
0:40:41 > 0:40:45We wrote round to all the astronomical observatories in Britain
0:40:45 > 0:40:47saying, "Have you had any programme going
0:40:47 > 0:40:50"which might possibly cause radio interference?"
0:40:53 > 0:40:56But the observatories wrote back with the all clear.
0:40:56 > 0:41:00There was nothing obviously interfering with her telescope.
0:41:00 > 0:41:03It's very easy when doing research, to try and
0:41:03 > 0:41:07brush over those things that don't quite fit into your view of things.
0:41:07 > 0:41:09It's much easier and much more convenient
0:41:09 > 0:41:11if it sort of fulfils your prejudices.
0:41:11 > 0:41:15She didn't do that - she found this thing that didn't really make sense,
0:41:15 > 0:41:17and she kept at it and was concerned
0:41:17 > 0:41:19as it became more and more obvious
0:41:19 > 0:41:21that it wasn't making any conventional sense.
0:41:21 > 0:41:24So I think that approach was very important.
0:41:25 > 0:41:28Bell Burnell enlisted the help of another radio telescope,
0:41:28 > 0:41:30to prove to all her doubters that the signal
0:41:30 > 0:41:33was in fact coming from the cosmos.
0:41:33 > 0:41:35She finally convinced Hewish
0:41:35 > 0:41:37that this was something to pay attention to.
0:41:39 > 0:41:41The big mystery was:
0:41:41 > 0:41:44what in the universe could be producing this signal?
0:41:44 > 0:41:47It looked like a series of equally spaced pulses.
0:41:47 > 0:41:49I don't know what I had expected
0:41:49 > 0:41:53but I certainly didn't expect regular pulsations.
0:41:53 > 0:41:56Stars and galaxies don't pulse like that.
0:42:00 > 0:42:02Hewish ruled out the possibility that it was
0:42:02 > 0:42:03coming from an object,
0:42:03 > 0:42:05because it pulsed too regularly and quickly
0:42:05 > 0:42:07for any known star or galaxy.
0:42:07 > 0:42:10Which led them to consider another explanation.
0:42:11 > 0:42:14Second reactions not really voiced very loud were:
0:42:14 > 0:42:16perhaps it's little green men?
0:42:24 > 0:42:26While the leaders of the radio astronomy group
0:42:26 > 0:42:30started considering their response to alien communication,
0:42:30 > 0:42:34Bell Burnell remained unconvinced, and returned to her telescope.
0:42:36 > 0:42:40She was very self-contained, very self-motivated,
0:42:40 > 0:42:43somebody who kept herself to herself.
0:42:43 > 0:42:46Wasn't really a great socialite in the group.
0:42:46 > 0:42:49Not that my memory is that it was particularly a social group,
0:42:49 > 0:42:51there were people who would get together -
0:42:51 > 0:42:55but she was somebody who tended to be and preferred to be on her own.
0:42:55 > 0:42:58Sometimes in research you can know too much,
0:42:58 > 0:43:01and it's the youngster who's ignorant
0:43:01 > 0:43:03or somebody coming in from outside
0:43:03 > 0:43:06that says, you know, the emperor has no clothes on,
0:43:06 > 0:43:10that actually is telling the truth, can see the truth.
0:43:11 > 0:43:14I think in order to make scientific discoveries,
0:43:14 > 0:43:17you really have to be open to the possibility of something
0:43:17 > 0:43:18quite unexpected.
0:43:18 > 0:43:20Jocelyn was somebody who WAS open to that,
0:43:20 > 0:43:22and she found something quite unexpected.
0:43:25 > 0:43:29Bell Burnell was rigorous, keeping meticulous records
0:43:29 > 0:43:32and analysing them in painstaking detail.
0:43:32 > 0:43:36She was dogged in her pursuit of an explanation.
0:43:36 > 0:43:39I was analysing chart from another piece of sky,
0:43:39 > 0:43:43and thought I saw a piece of this scruffy kind of signal.
0:43:45 > 0:43:47Looked exactly like what I was seeing before
0:43:47 > 0:43:50but from a totally different bit of the sky.
0:43:51 > 0:43:54Right. I thought, "I'm not going to bed tonight,
0:43:54 > 0:43:57"I'm going out to the observatory."
0:43:57 > 0:43:59And I switched on the high speed recorder,
0:43:59 > 0:44:02in came, blip, blip, blip, blip, blip.
0:44:02 > 0:44:07Clearly the same family, the same sort of stuff.
0:44:07 > 0:44:10And that was great, that was really sweet.
0:44:10 > 0:44:13Now, the people here say that
0:44:13 > 0:44:17if they got three signals as exactly spaced as that,
0:44:17 > 0:44:18it would be very unusual.
0:44:18 > 0:44:21If they got four, it would be phenomenal.
0:44:21 > 0:44:25Well, they've had pulses as exactly spaced as that 24 hours of the day
0:44:25 > 0:44:26since November.
0:44:28 > 0:44:29It was easier with the second one,
0:44:29 > 0:44:31and that was a great relief in many ways
0:44:31 > 0:44:35because it removed this possibility of it being little green men.
0:44:35 > 0:44:38Highly unlikely that several lots of little green men would be
0:44:38 > 0:44:40all signalling to us,
0:44:40 > 0:44:43all at the same frequency, all at the same time.
0:44:46 > 0:44:48With little green men ruled out,
0:44:48 > 0:44:52this had to be a brand-new type of cosmological object,
0:44:52 > 0:44:55behaving in a way that astronomers had never expected.
0:44:58 > 0:45:01The faint blips from space so nearly dismissed as error
0:45:01 > 0:45:03took the world by storm.
0:45:03 > 0:45:09The new objects were called pulsars, because they pulsed so regularly.
0:45:09 > 0:45:11For Bell Burnell, it was a personal vindication
0:45:11 > 0:45:13for her years of struggle.
0:45:17 > 0:45:22Seeing the article in print was tremendous,
0:45:22 > 0:45:26and I remember sending a copy of the paper to my physics teacher.
0:45:28 > 0:45:31- INTERVIEWER:- And that's your physics teacher at The Mount?
0:45:31 > 0:45:33At The Mount, yes. My physics teacher at The Mount.
0:45:33 > 0:45:35And how did he react to it?
0:45:35 > 0:45:40He had actually alerted the school.
0:45:42 > 0:45:44There was a lot of publicity.
0:45:44 > 0:45:47Mr Tillet had seen this, and told the school.
0:45:50 > 0:45:55There aren't so many people that take up physics as a profession,
0:45:55 > 0:45:59and certainly relatively few women of my generation,
0:45:59 > 0:46:04so Mr Tillet followed with some interest my career.
0:46:04 > 0:46:08And I was really pleased that he was still around
0:46:08 > 0:46:09at the time of the discovery.
0:46:13 > 0:46:15Further investigation showed
0:46:15 > 0:46:18that pulsars are the dense remains of rapidly spinning dead stars
0:46:18 > 0:46:21that emit beams of radiation.
0:46:22 > 0:46:24With each rotation, the beam sweeps
0:46:24 > 0:46:26in and out of the Earth's line of sight.
0:46:28 > 0:46:31And when they're found in pairs,
0:46:31 > 0:46:33they gradually move closer to each other.
0:46:34 > 0:46:39This behaviour indicated the existence of gravitational waves -
0:46:39 > 0:46:42distortions in space-time produced by massive objects.
0:46:44 > 0:46:46It's a phenomenon predicted
0:46:46 > 0:46:49by Einstein's theory of general relativity.
0:46:51 > 0:46:53It was the strongest evidence yet for the theory
0:46:53 > 0:46:55that Einstein had developed
0:46:55 > 0:46:59using just the power of maths and abstract thought.
0:47:02 > 0:47:05APPLAUSE
0:47:06 > 0:47:08'Professor Antony Hewish...'
0:47:08 > 0:47:12Antony Hewish won the 1974 Nobel prize
0:47:12 > 0:47:14for his role in the discovery of pulsars.
0:47:16 > 0:47:21Controversially, Bell Burnell was not included.
0:47:21 > 0:47:24But she has remained remarkably philosophical about it.
0:47:25 > 0:47:30You can actually do extremely well out of not getting a Nobel prize.
0:47:30 > 0:47:34And I have had so many prizes and so many honours
0:47:34 > 0:47:36and so many awards,
0:47:36 > 0:47:38that actually I think I've had far more fun
0:47:38 > 0:47:41than if I'd got a Nobel prize, which is a bit flash in the pan -
0:47:41 > 0:47:45you get it, you have a fun week and it's all over,
0:47:45 > 0:47:47and nobody gives you anything else after that
0:47:47 > 0:47:48cos they feel they can't match it.
0:47:50 > 0:47:53But Bell Burnell's discovery not only advanced
0:47:53 > 0:47:55our understanding of the universe,
0:47:55 > 0:47:57it also forced physicists around the world
0:47:57 > 0:48:01to think twice before they dismissed the unconventional.
0:48:05 > 0:48:09The scene was now set for other novel ideas in cosmology
0:48:09 > 0:48:11to be taken a little more seriously than before.
0:48:19 > 0:48:23Good news for another Cambridge PhD student
0:48:23 > 0:48:27who was not only pursing an idea rejected by other physicists,
0:48:27 > 0:48:30but was also facing his own personal struggle.
0:48:36 > 0:48:42In the early 1960s, Stephen Hawking was a normal, beer-swilling student,
0:48:42 > 0:48:46living life to the full while his physics studies took a back seat.
0:48:48 > 0:48:51However, his life would change for ever
0:48:51 > 0:48:53when at the age of 21
0:48:53 > 0:48:57Hawking was diagnosed with motor neurone disease.
0:48:57 > 0:49:01I was given two and a half years to live.
0:49:01 > 0:49:05I have always wondered how they could be so precise about the half.
0:49:06 > 0:49:09Its first effect was to depress me.
0:49:09 > 0:49:13I seemed to be getting worse fairly rapidly.
0:49:13 > 0:49:16There didn't seem any point in doing anything
0:49:16 > 0:49:19or working on my PhD,
0:49:19 > 0:49:23because I didn't know I would live long enough to finish it.
0:49:26 > 0:49:29While he struggled to adjust to the diagnosis,
0:49:29 > 0:49:34Hawking fell in love and married a family friend, Jane Wilde.
0:49:35 > 0:49:38I certainly wouldn't have managed it without her.
0:49:39 > 0:49:44Being engaged to her lifted me out of the slough of despond I was in.
0:49:44 > 0:49:47But then things started to improve -
0:49:47 > 0:49:50the condition developed more slowly
0:49:50 > 0:49:53and I began to make progress in my work.
0:49:53 > 0:49:55His spirits were buoyed,
0:49:55 > 0:49:58but Hawking believed he didn't have long to live.
0:49:58 > 0:50:01Motivated by a sense of his own mortality,
0:50:01 > 0:50:04he was determined to complete his PhD at Cambridge.
0:50:07 > 0:50:11In it, he applied general relativity to what we see in the universe,
0:50:11 > 0:50:13and showed that at the big bang
0:50:13 > 0:50:16there had to be what's known as a singularity -
0:50:16 > 0:50:21a infinitely small and dense point in space-time.
0:50:21 > 0:50:24In the 1960s, it was a thing that most physicists
0:50:24 > 0:50:26didn't believe existed.
0:50:26 > 0:50:30Roger Penrose was one of his examiners.
0:50:30 > 0:50:33He was very good at picking up ideas.
0:50:33 > 0:50:36When he came down to London when I was giving a talk -
0:50:36 > 0:50:39this was on some cosmological thing -
0:50:39 > 0:50:42I remember him particularly asking very awkward questions!
0:50:42 > 0:50:44So er...
0:50:44 > 0:50:49OK, good questions. I had to think a bit before giving the answer.
0:50:49 > 0:50:51So a bit of an awkward cuss, you would say.
0:50:51 > 0:50:55Not afraid to bring out issues which
0:50:55 > 0:50:58a young student might be a little shy of bringing up,
0:50:58 > 0:51:01so he wasn't shy at all in that way.
0:51:03 > 0:51:06Hawking remained at Cambridge University,
0:51:06 > 0:51:10and his career in astrophysics went from strength to strength.
0:51:12 > 0:51:14Although he had outlived his original diagnosis,
0:51:14 > 0:51:17his health was inevitably deteriorating.
0:51:19 > 0:51:22He could speak for quite a while,
0:51:22 > 0:51:25but largely only in ways that
0:51:25 > 0:51:27his close colleagues could understand him.
0:51:27 > 0:51:31HAWKING SPEAKS INDISTINCTLY
0:51:31 > 0:51:35Now, it just so happens that we have the universe here...
0:51:38 > 0:51:40INDISTINCT CONTRIBUTION FROM AUDIENCE
0:51:40 > 0:51:41- LAUGHTER - Sorry.
0:51:41 > 0:51:44I'd speak to him for a while, and...
0:51:44 > 0:51:47A fair amount of to and fro, and I could understand what he was saying
0:51:47 > 0:51:50more or less and he could understand what I was saying.
0:51:50 > 0:51:53But then he'd say something that... I couldn't understand a word of it.
0:51:53 > 0:51:55And he'd spell it out letter by letter.
0:51:55 > 0:51:58And it would either be a joke,
0:51:58 > 0:52:03- or an invitation to dinner. - HE LAUGHS
0:52:03 > 0:52:05Something which was on a personal nature not technical at all,
0:52:05 > 0:52:08so technical things were much easier to understand.
0:52:11 > 0:52:13Despite his ailing physical health,
0:52:13 > 0:52:16Hawking's mind was sharp and his will strong.
0:52:17 > 0:52:19HAWKING SPEAKS INDISTINCTLY
0:52:32 > 0:52:34Stephen's lucky in that he chose one of the few fields
0:52:34 > 0:52:37in which his disability is not a serious handicap.
0:52:37 > 0:52:38HE SPEAKS INDISTINCTLY
0:52:41 > 0:52:43Cos most of his work is really just thinking.
0:52:43 > 0:52:45HE SPEAKS INDISTINCTLY
0:52:48 > 0:52:50And his disabilities don't stop him doing that.
0:52:50 > 0:52:52HE SPEAKS INDISTINCTLY
0:52:55 > 0:52:57In a way, they give him more TIME to think.
0:53:03 > 0:53:06I think probably THE most determined person
0:53:06 > 0:53:08I've ever known.
0:53:08 > 0:53:10I remember staying at his house
0:53:10 > 0:53:13in Little Clarendon Street, wherever it was -
0:53:13 > 0:53:16there was a three-storey, little narrow house,
0:53:16 > 0:53:18much higher than it was wide.
0:53:18 > 0:53:22And when it came to the time when he wanted to go to bed
0:53:22 > 0:53:24he would crawl up the stairs -
0:53:24 > 0:53:28he refused to have anybody help him in any way -
0:53:28 > 0:53:30he would crawl up the stairs, it would
0:53:30 > 0:53:32take him about a quarter of an hour to get up the stairs,
0:53:32 > 0:53:36put himself to bed, do everything he could for himself.
0:53:40 > 0:53:43Hawking's determination was also evident in his science.
0:53:45 > 0:53:48Not only had his PhD shown singularities
0:53:48 > 0:53:50WERE present in the universe...
0:53:52 > 0:53:54..along with Penrose, he proved that they also lay
0:53:54 > 0:53:57at the heart of another curiosity - black holes.
0:53:59 > 0:54:02Hawking was now used to pushing the boundaries of cosmology.
0:54:06 > 0:54:10But his greatest discovery came in 1974,
0:54:11 > 0:54:15when he showed that black holes aren't entirely black,
0:54:15 > 0:54:16but emit SOME light.
0:54:18 > 0:54:21Radiation created by the strange quantum effects
0:54:21 > 0:54:23that occur at the edge of the black hole.
0:54:25 > 0:54:29Where Dirac had previously managed to unite special relativity
0:54:29 > 0:54:31and quantum theory,
0:54:31 > 0:54:34Hawking was the first to use both general relativity and quantum
0:54:34 > 0:54:36in the same explanation.
0:54:38 > 0:54:40Where I have had success,
0:54:40 > 0:54:44it has been because I have approached problems from a different angle.
0:54:45 > 0:54:48I rely on intuition a great deal.
0:54:49 > 0:54:51I try to guess a result.
0:54:52 > 0:54:54But I then have to prove it.
0:54:56 > 0:55:00That is how I found black holes aren't completely black.
0:55:01 > 0:55:03I was trying to prove something else.
0:55:05 > 0:55:08There's nothing like the eureka moment
0:55:08 > 0:55:11of discovering something that no-one knew before.
0:55:12 > 0:55:16I won't compare it to sex - but it lasts longer.
0:55:18 > 0:55:21Hawking's unifying idea was revelatory, yet complex.
0:55:23 > 0:55:25And having had a family of his own,
0:55:25 > 0:55:28he had a burning ambition now to popularize his science.
0:55:29 > 0:55:32In 1988, he published A Brief History Of Time,
0:55:32 > 0:55:35which aimed to explain the mysteries of the universe
0:55:35 > 0:55:36to non-scientists.
0:55:39 > 0:55:41It became an international bestseller.
0:55:41 > 0:55:44The contrast between his imprisoned body
0:55:44 > 0:55:47and a mind roaming the cosmos fascinated the public.
0:55:48 > 0:55:53All my life I have been fascinated by the big questions that face us,
0:55:53 > 0:55:58and have tried to find scientific answers to them.
0:55:58 > 0:56:01Perhaps that's why I have sold more books on physics
0:56:01 > 0:56:03than Madonna has on sex.
0:56:06 > 0:56:09He was catapulted into celebrity,
0:56:09 > 0:56:13and became the most famous living scientist.
0:56:14 > 0:56:15He clearly likes his fame -
0:56:15 > 0:56:18one can see that this is something
0:56:18 > 0:56:21he does get a lot of enjoyment out of,
0:56:21 > 0:56:22having big crowds and...
0:56:22 > 0:56:25So there's an element of showmanship about it all.
0:56:28 > 0:56:31Hawking's strength as a communicator of science
0:56:31 > 0:56:34has opened a window onto the cosmos,
0:56:34 > 0:56:36and enabled us all to marvel at its glory.
0:56:45 > 0:56:47Throughout the 20th century,
0:56:47 > 0:56:49the secrets of the universe
0:56:49 > 0:56:52have been unravelled by extraordinary individuals.
0:56:57 > 0:56:59Inspirational men and women,
0:56:59 > 0:57:01who have discovered fundamental new truths...
0:57:06 > 0:57:10..about everything from the subatomic
0:57:10 > 0:57:13to the extremely massive.
0:57:17 > 0:57:20But today, science has changed.
0:57:21 > 0:57:25Many of the most exciting frontiers of physics are being explored
0:57:25 > 0:57:30not by individuals, but by large groups of scientists,
0:57:30 > 0:57:32working together in collaborative units.
0:57:33 > 0:57:36The subject now is much more sophisticated,
0:57:36 > 0:57:38in that whether you're a space astronomer,
0:57:38 > 0:57:41an optical astronomer or a particle theorist,
0:57:41 > 0:57:45you depend on very large instruments, at CERN for instance.
0:57:45 > 0:57:47You have the designers of the instruments,
0:57:47 > 0:57:49the operators of the instruments,
0:57:49 > 0:57:51those who analyse the data, the phenomenologists
0:57:51 > 0:57:55and the theorists who try to make sense of it at a deeper level.
0:57:55 > 0:57:58So the story of physics in the 21st century
0:57:58 > 0:58:00is more about collective endeavour.
0:58:01 > 0:58:04And although we may miss the individual personalities,
0:58:04 > 0:58:07it is a price we may have to pay
0:58:07 > 0:58:09if we are to stand a chance of solving
0:58:09 > 0:58:12the remaining secrets of the universe.