Sir Martin Rees

Speaker 30:00

Hello, I'm Kirsty Young, and this is a podcast from the Desert Island Discs Archive. For rights reasons we've had to shorten the music. The programme was originally broadcast in nineteen ninety seven, and the presenter was Sue Lawley.

Presenter0:28

My castaway this week is an astronomer. From his base at Cambridge University, he spends his time trying to understand cosmic evolution. In other words, how the Earth and Solar System were formed. But the seeker after such big truths is no dreary academic with his head in the stars. Balanced, cultured, and passionate about the need to widen interest in scientific subjects, it's his contention that the general ideas of cosmology can be expressed simply and clearly. The concepts involved are relatively straightforward, he says. It's more difficult to understand a frog than the cosmos. He is a Royal Society professor and the Astronomer Royal, Sir Martin Rees. First things first, Sir Martin, what does the Astronomer Royal do? I have this image of you tutoring the young princes about the sky at night.

Sir Martin Rees1:18

Well, Astronomer Royal is a rather antique title. It dates back to the 17th century. It used to be the person who ran the Greenwich Observatory, but for the last 25 years it's just been an honorary title given to a senior astronomer. And my day job, as it were, is as a professor at Cambridge University, and I hold this title, which is a purely honorary one.

Presenter1:38

But if you did it's a wonderful title, isn't it? It sounds very grand. I mean if if you did go to Buckingham Palace uh you might begin by telling them that the cosmos is is simpler to understand than the frog. Um how can that be? This unknown blackness that inspires such awe and fear in us all?

Sir Martin Rees1:54

Well, it inspires tremendous awe and it's immense in scale, but it is amazing that we have been able to understand quite a lot about our cosmic origins, to see not only how the Earth evolved, but how our solar system evolved, and to trace cosmic history right back to what we call the Big Bang, where everything started. And the reason I think we can do this is that, in a sense, the universe, though large, is simple in it it's governed by universal laws that we can understand. Whereas something like an animal is much more complicated because although it's small, it has got far more layers of structure in it. The fact that things are big doesn't in itself mean that they are harder to understand than everyday things we find here on Earth.

Presenter2:39

And yet to most of us the concept of a black hole, you know, this kind of nothingness which we are told is there and people argue even if they are there, you know, that particular concept, a hole in space into which objects and bits and pieces disappear, is terribly difficult to grasp.

Sir Martin Rees2:55

Oh, it is. I think one thing we do learn is that when we talk about extreme conditions, like black holes where gravity is very strong, and like the beginning of the universe and perhaps the end of the universe, then the concepts transcend what we have in common sense because the conditions are far more extreme than we are used to and can study in the lab. So certainly we come up against a frontier or even a barrier when we can't do more than speculate. But what's amazing is we've been able to get so far through observations and progress in the last 10 or 20 years in particular that we can seriously talk about questions like how did the universe begin? Will it go on forever? Why do stars exist? How do they evolve? And are there planets and are there other kinds of life around other stars? We can at least talk about these questions. And when I started my research 25 years ago, most of them were entirely speculative. And so there's been tremendous progress to bring these within the range of serious science.

Presenter3:52

But let me ask you a really big question. How much do we need to know what goes on out there? I mean, is your work unlike the science of genetics or nuclear physics or whatever? Is it really much more of a of a cultural enterprise?

Sir Martin Rees4:08

One dimension is clearly cultural. Just as Darwin taught us in the 19th century how life is evolved on the earth, so we're trying to understand cosmic evolution, understand how the earth emerged, how the atoms we are made of evolved from the Big Bang. So it's cultural in the same sense that Darwin gave us a cultural concept and taught us a new way of understanding our place in nature.

Presenter4:32

Right, more of all of that in a moment, more black holes, more of the cosmology, but first of all, tell me about your first record.

Sir Martin Rees4:39

My first record is one of Beethoven's Razumovsky Quartets. I think I need no excuse for picking a Beethoven Quartet, but I chose this particular movement because I read that Beethoven was inspired to write it by looking up at the stars and thinking about the music of the spheres.

Presenter5:56

Part of the second movement of Beethoven's string quartet in E minor, opus fifty nine, number two, Razumovsky, played by the Medici string quartet. Beethoven was inspired by the sky at night, Sir Martin. Is the opposite true? Can you in your astronomy be inspired by music?

Sir Martin Rees6:11

I wouldn't say it's an inspiration, but certainly listening to music is an important part of my life and my relaxation. But you'd

Presenter6:17

I'd like to have been amused.

Sir Martin Rees6:17

Musician would

Presenter6:18

Cheers.

Sir Martin Rees6:19

I suppose I'd like to have been a composer more than anything else. I was put to the piano at a fairly early age, but it wasn't long before I realised that I had no particular talent in that direction. But I always enjoyed music. I even enjoyed singing, although rather ineptly. But fortunately I went to a school where there was a very large choir that did performances, and one didn't need to be very adept at singing in order to be part of that choir, so I enjoyed the experience of participating.

Presenter6:45

When did you decide to become an astronomer? When did that ambition develop?

Sir Martin Rees6:51

In fact, I wasn't someone who right from an early age had a definite direction of where they wanted to go. When I was young, I was very interested in science and how things worked. But I think honestly, what happened was that when I was at school, I found that I was good at maths and science, rather bad at languages. So actually, it was my badness at Greek and Latin which perhaps steered me most towards studying science and maths in my final years at school, which then led on to me doing those subjects at university. So I didn't have a definite direction from the start.

Presenter7:22

So you went up to Cambridge to Trinity to read what's been described as the most difficult mathematics course in the world, was it?

Sir Martin Rees7:28

I found it fairly difficult, but I quite liked the problem solving aspects, and I did all right in the exams most of the time, but I think I knew already that I really wasn't cut out to be a mathematician.

Presenter7:40

A pure mathematical

Sir Martin Rees7:40

A pure mathematician, I hoped I could find something to which I could apply my skills in mathematics and physics, and eventually I found that these could be applied to a subject like astronomy and cosmology.

Presenter7:53

So you were sort of scouting around for something, were you?

Sir Martin Rees7:55

That's right. I was very uncertain and in fact in my final year at university I thought I might do

Sir Martin Rees8:02

Astronomy and cosmology, I thought I might do economics. I was as uncertain as that, but I was lucky in having a very good research supervisor who was also Stephen Hawking's supervisor at the same time. Stephen was a couple of years ahead of me then. But also I was lucky because the subject was at an exciting stage and that new discoveries were being made in the mid-1960s, which it was exciting to try and explain. And that therefore meant that since the discoveries were new, the experience of older people was, as it were, at a discount and it was possible for young people to start making significant contributions. But the other respect in which I've been very lucky is that although I've now been doing the subject for nearly 30 years, the pace of new advances has not slowed down in any way. In the last two years, there have been just as many important new discoveries as at any period before that. So as the frontiers of the subject have advanced, their periphery, as it were, has got longer, and there's more and more to think about.

Presenter8:59

Hmm. Let's have another record.

Sir Martin Rees9:01

Well, in fact, I grew up in Shropshire, and I couldn't think of a great Shropshire composer, but over the border in Worcestershire, of course, is the land of Edward Elgar, and I thought I would choose an Elgar piece. And since we are thinking about Irelands, what more appropriate than something from Elgar's Sea Pictures?

Speaker 49:38

And for that sin, the brain fire.

Speaker 49:45

Oh, that sea will bring it with war.

Sir Martin Rees9:48

Fill it with water.

Speaker 49:53

Eyelids raised too long.

Presenter10:18

Dame Janet Baker singing part of A Sabbath Morning at Sea from Elgar's Sea Pictures with the London Symphony Orchestra conducted by Sir John Barbarolly.

Presenter10:32

We all happily use this phrase big bang theory. I'm not sure a lot of us know exactly what it means. Give give us the layman's definition, Sir Martin.

Sir Martin Rees10:41

It's basically the idea that at some time in the past, about 10 or 15,000 million years ago, everything that's now in the universe was squeezed to a very hot dense state, hotter and denser than the middle of the Sun is now, and that the universe has expanded from that dense state to produce, after this immense span of time, the cosmos we see around us. And this is an idea which goes back about 50 or 60 years, but the evidence for it is rather more recent. Indeed, when I started my research, it was rather controversial whether there was indeed a Big Bang or whether, as people like Fred Hoyle argued, the universe was still in a so-called steady state, having existed from everlasting to everlasting in the same situation.

Presenter11:23

Didn't he invent the term as a a a derisive term, really, big bang? That's right.

Sir Martin Rees11:28

That's right. The name Big Bang was due to Fred Hoyle and he didn't like then and still doesn't like the theory, but people haven't really thought of a more dignified name for this concept, even though most of us believe very strongly that the Big Bang idea has a lot of evidence in its favour, and indeed is probably as well established as many ideas about the early history of the earth, which we learned from geology and looking at fossils.

Presenter11:52

But do we know what made the Big Bang happen? Do we know what happened in that one second when it banged?

Sir Martin Rees11:58

No, we don't. When I say we believe in the Big Bang, we believe we can extend cosmic history back to a stage before any stars or galaxies formed, when everything was squeezed this dense state. But of course, you can always ask how far back can we go? Because as we go back further and further, nearer and nearer to the beginning, everything gets denser and denser, hotter and hotter and more and more extreme. And of course, we then get less confident because when conditions get beyond what we can study in the lab,

Sir Martin Rees12:29

We don't really know exactly what happens, and so we are still flummoxed about the very early stages of the Big Bang.

Presenter12:35

So we can go back 15 billion years, but not to the one second before that.

Sir Martin Rees12:39

That's right, and this is of course in itself amazing progress from the time when we didn't really understand evolution here on earth.

Presenter12:47

And you've said, therefore, as a result of believing in the Big Bang theory, um, that we are stardust. That's very romantic as a concept, isn't it?

Sir Martin Rees12:56

Well the idea there is that the material that emerges from the Big Bang is just the simplest kind of atoms, mainly just hydrogen, and all the things we are made of, all the carbon and oxygen and other atoms in our bodies and in our blood, those atoms were actually made inside stars. This is an idea which Fred Hoyle actually pioneered, the idea that what keeps a star shining is nuclear reactions.

Sir Martin Rees13:23

The same sort of thing is happening in an H-bomb, but this is happening deep inside stars. And when stars die, they throw back out into space all their nuclear waste, as it were. And that nuclear waste then finds itself in interstellar clouds and condenses into new stars. So we can think of our entire galaxy, our Milky Way, as a sort of ecosystem where atoms are being recycled through one star and then through our sun, and of course when our sun dies, perhaps through other stars in future.

Presenter13:53

So that's how the universe began. Let's um before we go any further into it, let's pause for another piece of music. Tell me about your third record.

Sir Martin Rees14:00

Well my third record is a Chopin Polonaise. This particular one I chose because when I learnt the piano as a child I very much wanted to play this particular piece for some reason, that I was always frustrated that I could never get beyond the first few bars before making some major goof. So this piece has rather mixed associations for me, but I'd like to hear it nonetheless.

Presenter15:17

Artur Rubinstein playing the opening of Chopin's Polonaise in A, Opus forty, number one. Let's move on then, Sir Martin, to the next big question. Could there be other intelligent life out there, or are we, you know, this planet Earth, some kind of fluke?

Sir Martin Rees15:33

Well, that's about the most important question we can ask, really. And unfortunately, we're far from answering it, in my opinion, because it's really a question for biologists, not a question for astronomers, because astronomers can say that there are almost certainly other planets around other stars, there are other solar systems. We even have evidence for that. So we can say that there are planets like the Earth around stars like the Sun.

Sir Martin Rees15:56

But what we don't know is whether life gets started automatically when you have the right environment. That's a question for biologists. Most people think it does, but we don't really know the answer.

Presenter16:07

But you surely as an astronomer would have picked up the signal somewhere. I mean, if there's somebody out there, they would have surely been trying to communicate in some way. They'd have picked up ours, wouldn't they?

Sir Martin Rees16:17

They would, but of course we've got to get from simple life to life that's complex and intelligent. And of course we've got to bear in mind that even if there's intelligent life out there, they may not want to send out signals. They may be living a very happy, contemplative life, not wanting to send out any signals and reveal their presence. So absence of evidence isn't evidence of absence in this context. The other thing we learn from astronomy is that we are not near the culmination of the universe. Even our sun.

Sir Martin Rees16:46

is less than halfway through its life. And so you can imagine that even if life is unique to the earth now, it might be possible for species or entities descended from us to spread through the galaxy and beyond. So we mustn't think of ourselves as being the combination in any sense.

Presenter17:03

But are you suggesting, then, that in your view it's how how definitely can one put it it's simply a matter of time before we spot something out there that is going to either confirm or prove the negative that there is no other life?

Sir Martin Rees17:21

I don't know. It would be hard to prove the negative because if there was life out there, it might not be detectable in any way. It'll be a very long time before we can actually get an image of a planet around another star and tell if there's life on it. So it'd be very hard to get evidence for life unless it's the kind of life that's technologically like us. And that's, of course, perhaps a very rare kind of life indeed. So

Sir Martin Rees17:43

I would say there's a very small chance, but a chance that's worth shooting for, that we will detect life, and that's why I support efforts to search for it. But even if those searches fail, I don't think we should conclude we're alone in the universe. There may be life in some less obvious manifestation.

Presenter18:01

More music, number four.

Sir Martin Rees18:03

Well, I'm based in Cambridge and I'm also a member of King's College and that of course is famous for its marvellous choir and so I wanted to have at least one record by the King's College Choir and conducted by their superb music director Stephen Clearbury and the piece I've chosen is Foray Requiem.

Speaker 418:40

Wow.

Speaker 418:41

So she

Presenter19:22

Part of In Paradisum from Foray's Requiem, sung by the choir of King's College, Cambridge, with the English Chamber Orchestra, conducted by Stephen Clearbury.

Presenter19:31

So you're an interpreter who tries to analyse what other people have observed and come to some conclusion about those observations?

Sir Martin Rees19:39

That's right. I tend to try and tie together what's observed by different people with different techniques and to see if I can make sense of it, making use of what I know about physics and mathematics. And this involves also collaboration with uh other theorists who have expertise I lack. So my work tends to be very interactive and lots of collaboration with many other people.

Presenter19:59

But it also requires you, doesn't it, to t to take a conundrum that you've been presented with by these observers and to come to some sort of great conclusion about and then see if you can make that work, see if you can prove it mathematically.

Sir Martin Rees20:13

That's right. One hopes to have some insight which perhaps makes sense of the observations. But then, of course, you want to check that by making some more observations. And very often, what we do is we come up with some idea, and if it was right, it would have certain consequences. We then do further checks, and more often than not, it doesn't work out, sometimes it does, and we're vindicated. So it's been very

Presenter20:33

Well, you're being very modest here,'cause I know you have the reputation of being something of a scientific magician. Didn't you really quite quickly and went almost off the top of your head.

Presenter20:42

explain to people exactly why quasars behaved as they behaved.

Sir Martin Rees20:45

Well, I was lucky in that early on I explained what turned out to be one very puzzling feature of them. So I hit the mark once, but uh many times I failed. But my work tends to be

Sir Martin Rees20:55

trying to interpret data are not very mathematical. It's different from, say, what Stephen Hawking does. He tends to work in a very mathematical style, which is remote from observations. I tend to work on phenomena that are directly related to observation and experiments in a more synthetic way.

Presenter21:11

But obviously from what you say, you regard it as a as a creative business, which is which is perhaps something that people don't always imagine science to be a creative business. I mean in the in the age old argument of the two cultures,

Presenter21:23

Um

Presenter21:24

It is very difficult for a science to be so creative, isn't it? Because it's competitive. You've got to get on and find the answer before somebody else does.

Sir Martin Rees21:34

Well that's right. Science is creative in a sense. It's like invention where you've got to try and think of new ideas. And so one has original ideas. But the ideas aren't quite as distinctive as the ideas which one has in the humanities and arts. In a sense that in general, if I didn't have an idea, someone else would have the idea pretty soon. Whereas in the arts, of course, your work is original, individual, no one else is going to scoop you. This is quite well put in the context of Wagner. Someone said that Wagner took 10 years off in the middle of the ring cycle to write Tristan and the Meistersingers. He wasn't worried that someone would scoop him on Goethe Demrum. Whereas if you take time off in the middle of some scientific project, someone else is going to come up with the idea. So in science, your work doesn't have the same individuality as it does in the arts.

Presenter22:26

But is there any consolation here for the the fairly lowly research scientist? Do you think that perhaps he might have a greater chance of being relevant, because he might have proved or again disproved something that went towards the greater discovery? Whereas the odd novel or poem might come for nothing and be forgotten to morrow?

Sir Martin Rees22:45

That's right. The work is not only relevant but also durable. Even the modest contribution to science become part of the corpus of public knowledge, as it were. So we all feel that we are contributing something which is durable, even though in general the identity of who discovered that particular bit will be forgotten.

Presenter23:03

Tell me about your fifth record.

Sir Martin Rees23:05

Well, we mentioned Wagner and I'm not really a Wagnerian, but I do like the noise it makes, and I recall the experience of seeing Wagner on the stage for the first time, and I would like to have one Wagner piece, and I've chosen to have the great duet at the beginning of Gotta Demerung, the duet between Siegfried and Brunhilde.

Presenter24:23

Bernd Aldenhof and Birgit Nielsen as Siegfried and Brunnhild are taking leave of each other at the beginning of Wagner's Goethe Demmerung, with the Bavarian State Orchestra conducted by Hans Knappitzbusch.

Presenter24:35

So we come to another of the big questions, Sir Martin. How will it all end? Or or is the future infinite?

Sir Martin Rees24:42

Well, we don't know whether it's infinite or not. We know our universe is expanding. We know the future.

Sir Martin Rees24:48

Lies many billions of years ahead of us anyway, but there's an interesting question about whether the universe will go on expanding actually forever, or whether at some immensely distant epoch everything will collapse to what some people call the big crunch. And that would be rather like the fate which you would experience if you went too close to a black hole. Now, black holes are objects which Einstein speculated about and which we now know actually exist in the universe. They're objects that have collapsed, cutting themselves off from the rest of the universe, but leaving a gravitational imprint in space, as it were.

Presenter25:22

Am I right in understanding that that ninety per cent of the mass of the universe is missing? It's dark matter and we don't know what or where it is.

Sir Martin Rees25:31

Yes, indeed. This is a very embarrassing admission which all astronomers have to make that most of what we see in the universe is just a small and atypical fraction of all that's there, in that there are good reasons to think that there's at least ten times as much stuff pervading all of the universe than what we actually observe. And this is what we call a dark matter. We've no idea what it is. And we'd like to know obviously what it is, because it's rather embarrassing that the dominant part of the universe is completely unknown. But we'd also like to know how much of it there is, because the amount of dark matter is what determines the eventual fate of the universe, determines whether the universe will go on expanding forever or whether there's enough gravitating material in it to eventually stop the expansion. This is about 100 billion years from now, which is ten times further in the future at least.

Presenter26:18

Still be quite nice to know, though, wouldn't it? Somehow you feel we ought to.

Sir Martin Rees26:23

It makes you uneasy, that's it, to have this uncertain future.

Presenter26:25

Hmm.

Sir Martin Rees26:27

Me too.

Presenter26:28

Record number six.

Sir Martin Rees26:30

Well, this is something completely different. My wife, Caroline, is another academic, but of a very different kind from me. She's an anthropologist who spends a lot of time in eastern Siberia on collective farms and among the nomads of Mongolia. And I thought I would have a short extract from a Mongolian chant as a great contrast from all the rest of my selection.

Presenter27:19

My Beautiful Hang Eye Land, a Mongolian chant, which was recorded in 1974. You must have paused in all this cosmology, Sir Martin, to consider whether there was space for a creator, for a God, in all of this science.

Sir Martin Rees27:36

I really don't think that what we discover in cosmology helps to answer that question. I think if you'd asked that question of Sir Isaac Newton 300 years ago, he would have given a particular answer, whereas some of his contemporaries would have given a different answer. And so it is among my contemporaries. Some people interpret cosmology in a religious context, others don't. And I genuinely don't think there's any impact between the kind of science I do and any religious views that I might have. So I actually don't think that our work does have any particular relevance to theology. But it's a dull answer, but I really believe that.

Presenter28:08

But as you can see

Presenter28:10

But as you say, a lot of scientists say that knowing what you know and understanding what you understand, that that the concept of there being a God is is simply intellectually insupportable. But you don't feel able to wipe it away in that way.

Sir Martin Rees28:24

I think if science teaches me anything that's relevant to this question, it's that even simple things like a single atom are fairly hard to understand. And that, I suppose, makes me slightly suspicious of any claim to have more than a very incomplete and metaphorical understanding of something really complex and important. So I suppose my work makes me slightly sceptical of any

Sir Martin Rees28:46

Very strong dogma, but I don't think any more than that is relevant.

Presenter28:49

Hmm.

Presenter28:50

Record number seven.

Sir Martin Rees28:52

It's always nice if one comes across a work one hasn't heard before, and just about three months ago I happened to hear the Brahms Alto Rhapsody. That led me to buy a record of it which I then played over and over again. I think it's a marvellous piece.

Speaker 429:08

I

Presenter30:04

Part of Brahm's alto rhapsody sung by Anne Sophie von Otter, accompanied by the Arnold Schoenberg Choir and the Vienna Philharmonic, conducted by James Levine.

Presenter30:14

We the British have such a a strong history of scientific invention and discovery, you know, from the spinning jenny to penicillin to the cathode ray tube. And yet we as we approach the end of the twentieth century, it does seem and I think you've said this yourself we seem to have lost our scientific vitality. Why do you think that is? Is it simply a matter of money?

Sir Martin Rees30:34

I think it might be too strong to say we've lost the vitality. We are still probably the number two nation to the United States in science. But I think there is a issue of the prestige and standing of science, particularly among young people.

Sir Martin Rees30:47

And I think that although my work of astronomy and cosmology may seem remote from everyday concerns, I think it's an important subject to

Sir Martin Rees30:57

present to the public because unlike other high profile sciences it has a positive and non-threatening public image and I think it's important to enthuse young people with science because all too often at the age of fifteen or sixteen young people are turned off science and under our over specialized education system that of course means that they may foreclose the option of ever studying any science in depth.

Presenter31:22

So you think we should go on studying science through the sixth form even if you're specializing in the arts?

Sir Martin Rees31:22

So you think we

Sir Martin Rees31:27

Well, I think one should study some science. It's not because we want everyone to become scientists, obviously not.

Sir Martin Rees31:33

But because everyone ought to be well enough informed about science to participate in debates about how it's supplied. But I think there is something else, which is that certainly scientists aren't adequately appreciated in our country. And I think one has to give them the impression that they will be appreciated as much as, say, an accountant in order to make young people feel that a scientific career and a scientific training is going to be something which they will benefit from in the long run. So I think there's got to be a culture change in that sense.

Presenter32:02

Last record.

Sir Martin Rees32:04

Well, we talked earlier about the difference between science and the arts in creativity. There's another difference, which is that in

Sir Martin Rees32:12

Music and other arts, you can often get better and better as you get older. In the case of composers, their last works are often their deepest because they've had a long internal development.

Sir Martin Rees32:23

In the case of scientists, I'm afraid the best one can do is stay on a plateau. One hopes one doesn't get worse and can continue making a useful contribution, but in order to do good science as you get older, you've got to still be receptive to external influences, and that's what we find harder as we get older. And Richard Strauss is an example of a composer who made a great noise both literally and metaphorically when he was in his twenties, but went on until his eighties and produced some of his greatest works in his extreme old age.

Presenter33:46

Part of Metamorphosen, a study for twenty three solo strings by Richard Strauss, played by the English Chamber Orchestra conducted by Geoffrey Tate. If you could only take one of those eight records, Sir Martin, which one would it be?

Sir Martin Rees33:58

I think it would be the Foray Requiem. I think if one was going to listen to one last piece of music, that's the best choice.

Presenter34:03

What about your book?

Sir Martin Rees34:05

Well

Sir Martin Rees34:06

The choice of records is perhaps rather on the heavy side, because I chose records I could happily listen to over and over again, and I thought therefore I might need cheering up, so my book's going to be rather frivolous. I thought I'd choose Gary Larson's collected cartoons to remind me of the uh idiocies and surreal aspects of the world I'd be cut off from.

Presenter34:27

And what about your luxury?

Sir Martin Rees34:29

Well, I'm a rather lazy character and I was going to choose what I think is called a Jefferson chair. This is sort of reclining chair which Thomas Jefferson invented where you can have a sort of swivel table and a lamp and if I can have a little telescope swiveling onto it so much the better so I can sit back and contemplate and read comfortably.

Presenter34:50

Sir Martin Rees, thank you very much indeed for letting us hear your desert island discs.

Speaker 335:00

You've been listening to a podcast from the Desert Island Discs Archive. For more podcasts, please visit bbc.co. uk slash radio four.