Professor Carlo Rovelli

Speaker 40:00

This is the BBC.

Presenter0:03

Hello, I'm Kirsty Young. Thank you for downloading this podcast of Desert Island Discs from BBC Radio 4. For rights reasons, the music choices are shorter than in the radio broadcast.

Presenter0:14

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Presenter0:41

My castaway this week is the physicist Professor Carlo Rovelli. He is one of the founders of loop quantum gravity theory, and yes, it is as complex as it sounds, but take heart. He's not just a whiz at understanding gluons, hot black holes, and discontinuous time, he's really good at explaining it too. His most recent book, Seven Brief Lessons on Physics, is an international bestseller, and the importance of his original scholarship is considered so significant, he's even had a five-day scientific symposium devoted entirely to his work. Such is his rock star status, they called it Carlo Fest. If you tend to think of science as a reassuring depository of certainties, then think again. According to my guest, the foundation of science is an acute awareness of the extent of our ignorance. He says, I think physics is about escaping the prison of the received thoughts and searching novel ways of thinking of the world, about trying to clear a bit the misty lake of insubstantial dreams, which reflect reality like the lake reflects the mountains. And so welcome, Professor Rovelli. Your most recent book, then, so far I think it's sold well over a million copies. Now it's been translated into 41 languages, and it begins thus. These lessons are written for those who know little or nothing about modern science. Well, on behalf of us all, I want to say thank you for writing it in the first place. But why do you want to use your precious time up on people like me?

Professor Carlo Rovelli2:14

Thank you very much for this introduction. I think writing for the large public for me was a way to try to share a passion and uh to communicate the beauty that I was seeing, that I see in theoretical physics. So it's like uh telling a love story in which I was uh immersed and I'm still is.

Presenter2:35

And you have clearly as poetic a way of speaking as you do of writing. There seems to be no

Presenter2:40

Well, embarrassment on your part in turning it into

Presenter2:43

A notion that is as sort of romantically beguiling this idea of physics and science.

Professor Carlo Rovelli2:49

There is a picture of uh science which is common as something dry and uh cold and uh based on uh stricter rationality, equations, measurements, numbers. That's not the reality of the making of science, of course. Science is a passion in which uh men and women get involved and can't resist it and is a is a sequence of moments of desperation, moment of excitement and disappointment. In fact, mostly disappointment and sometimes uh moments of enthusiasm. The reality of science is full of passion. Plus it's my story or the story of my generation to not be shy and not be embarrassed about ourselves, about our weaknesses and just present them. We're weak and that's fine.

Presenter3:33

You have in your book that I mentioned likened Einstein's equation on the curvature of space to the rarefied beauty of a late Beethoven string quartet, and I wonder if that is indeed a valid point to make. Why is it that people don't have the same passion for equations as they clearly do have for Beethoven?

Presenter3:52

I

Professor Carlo Rovelli3:53

chose a late Beethoven quartet in this metaphor, because that's not easy music. It's music that requires uh getting into Beethoven and listening a lot and then uh slowly you you realize how beautiful this music. And I am not sure um there are many more people who appreciate late Beethoven than people who appreciate Einstein equations. I live in an environment when a lot of people have their eyes uh becoming shining when they think about Einstein equations, because they are beautiful, they are so

Presenter4:22

We're not going to hear um anything from late uh Beethoven string quartet to begin with, but tell me about this first piece of music. What are we gonna hear this morning? Uh Jenny's Joppling, uh, me and Bobby McGee. Why have you chosen this?

Professor Carlo Rovelli4:34

Well, it's a song that has represented, I think, more than anything else the music of my life. It's about liberty, it's about freedom, it's about breaking out, and it's about taking a risk, taking things all the way through. There's a line that says freedom is just another word for nothing left to lose, which is scary and at the same time marvelous, because you have to go and not be afraid jumping into things. That's the way to go, in my opinion. I've done that in my life. I never regretted any jump I did.

Speaker 45:11

Freedom is just another word for nothing left.

Speaker 45:17

I mean nothing hun if it ain't free

Speaker 45:21

And feeling good was easy to sign booze, you know

Speaker 45:32

Good enough for me and my Bobby area

Presenter5:40

That was Danis Joplin and me and Bobby McGee. And you said, Professor Carlo Rovelli, that it was chosen because you value liberty and freedom and breaking out. And you said you've never been afraid to jump. You're somebody who, in your own words, says that the search for knowledge is not nourished by certainty. It's nourished by a radical distrust in certainty. And so that, I guess, is about being the person who has not just the knowledge and the intellectual power, but the courage to take a jump. Tell me more about that.

Presenter6:10

Yeah.

Professor Carlo Rovelli6:10

I think that science is uh largely based on uh rebellion, a rebellion against the past. It's not a silly rebellion, it's a learned rebellion. It's it's a rebellion based on uh first uh knowing as much as possible, but then always being aware that in our current knowledge there is most likely something wrong, something missing, and something to be abandoned.

Presenter6:32

Donald Rumsfeld, of course, famously a few years back, spoke about known unknowns and then unknown unknowns. And I wonder how you how you stop yourself then sort of catapulting into flimsy conjecture of just thinking, you know, well, if I'm going somewhere that nobody's gone before, why is that a reasonable place to go, from what we do know?

Professor Carlo Rovelli6:51

Well, that's the risky aspect of science, and that's why it's jumping. And that's a difficult equilibrium that uh we have in the development of knowledge between uh uh change and uh preserving what is there. There is uh always in science a point in which one uh recognizes that there is a problem, there is something that doesn't work. Quantum mechanics doesn't talk to generativity. And so one has to take the courage and throw away something and try in an ent

Presenter7:19

intelligent way, but try. You've mentioned quantum mechanics, and I keep wanting to say to you, Can you try to explain it to me in the simplest possible terms? Because I've had a answer.

Professor Carlo Rovelli7:27

Oh, there's I see

Speaker 47:29

No.

Professor Carlo Rovelli7:29

Uh But it's impossible, isn't it?

Professor Carlo Rovelli7:38

Exactly. And the reason, I believe, is that quantum mechanics is a spectacularly successful theory, is something on which we build our computers, plenty of modern technology, but nevertheless is something we scientists have not yet fully understood. That's why it's hard to explain. We have some equations, we have some ideas, we have some pieces of things which are more or less clear. The world is granular in the small. Light is not continuous, but it's little packets of light, the photons. There is probability in the small. So we can say a number of things. But there is not yet a coherent picture of quantum mechanics, and that's why we have so much difficulty of telling what it is.

Presenter8:09

The photo

Presenter8:20

You specialize in examining uh paradoxes in the in the physical world. Explain this to me. You're Italian and yet you don't like garlic.

Presenter8:29

Is that true?

Professor Carlo Rovelli8:30

Garlic. I I walk away from a place where there's somebody who smells garlic. I just can't bear it.

Presenter8:35

I just wanted to check that that was for real. I found it so unusual. Tell me about your second piece, Professor Carla Rovelli. What are we going to hear now?

Professor Carlo Rovelli8:38

The one you select

Professor Carlo Rovelli8:42

Uh

Presenter8:42

But

Professor Carlo Rovelli8:42

I go in Italy because after all I'm Italian, Gianna Lanini is a little bit the sort of the genius jopling in Italy and this is a song that reminds me of those years in which I was going into my young rebellion in Italy. I was living at the time in a sort of funny place in the countryside. It was a mixture between a hippie commune, a attempt to recreate the old Greek school, a farm in the old Italian style. So a group of us boys and girls living together and listening to this sort of music.

Speaker 39:32

Segui la mi a ka eta

Speaker 39:35

It makes an older fight.

Speaker 39:38

Vernicha la tumente.

Speaker 39:41

You need a gut suta.

Speaker 39:46

She wasn't like me and voice

Speaker 39:49

Shiva la significant.

Speaker 39:52

La shot in your job.

Presenter9:53

Veni Ragazzo, that was Gianna Nannini. Was that when you were listening to that, Carlo Rovelli, was that the time you were in Umbria with a goat called Lucrezia? Was that the commune? Was that that time? Yeah, that's exactly that. That's exactly at that time. Nineteen fifty six, Verona, that was where and when you were born. What what was it like growing up there at that time? Verona is near

Speaker 310:00

Was that

Speaker 410:01

At that time?

Professor Carlo Rovelli10:05

Exactly.

Professor Carlo Rovelli10:13

Venice, Venice is a mixture of an incredible openness to the world.

Professor Carlo Rovelli10:20

But at the same time, especially in the land around, is an old agricultural

Professor Carlo Rovelli10:26

Poor countryside that became rich with the late Industrial Revolution and especially after the war. And fascism in Italy was long, it was not short like Nazism in Germany, and fascist culture was even pregnating quite a lot of the Verona in which I was born. So I grew up in an apparently happy and protected environment, but more and more feeling in a clash against this environment.

Presenter10:57

You say apparently happy. What do you mean apparently happy?

Professor Carlo Rovelli11:01

R. D. Lange says that uh we can destroy ourselves uh by violence masquerading as slaves. Uh I grew up in a very lovely family with a very loving Italian mother. I was an only child, completely uh immersed in this maternal love, which was great. It gave me security, gave me strength, but was also a prison from which I clearly had to escape at some point if I wanted to go my way and uh change the world view that I was finding around me in my family, my school, in my teachers, many of whom had uh nostalgia for fascism.

Presenter11:44

Ah. Did you feel that your mother sort of did you feel love too much? Was there too much scrutiny too much?

Professor Carlo Rovelli11:50

Definitely

Professor Carlo Rovelli11:51

Yes, I felt I couldn't do anything without her approval, and she was

Presenter11:56

Yeah.

Professor Carlo Rovelli11:57

It's not ready to let me Goal.

Presenter11:58

But when you were around about I think you were about seven, isn't it right that your mother sent you

Presenter12:03

All on your own over to England just to learn English. Yes. I mean, it was only for a week, but that's quite a long time in your life.

Professor Carlo Rovelli12:09

No, it was longer than that. Probably for two weeks. And then uh the year after I was in Bath and uh I was there for a month alone. Yeah. So I had a good education in which my family pushed me to be independent.

Presenter12:10

Yeah.

Presenter12:15

Yeah.

Professor Carlo Rovelli12:24

But then I took it seriously and I said, Oh, wonderful. I'm twelve. Now I'm grown up. I can do whatever I want. And what did you do?

Professor Carlo Rovelli12:33

Well, when I was twelve, just fight with my mum, but when I was uh fifteen, I just went. I chiked from Paris to Sofia in Bulgaria alone, sleeping outside in the countryside. And uh my parents were desperate.

Presenter12:40

When?

Professor Carlo Rovelli12:49

Yeah.

Presenter12:49

And how were you? I was happy. Much more of that to come, Carlo Rovelli. Tell me about your third piece of music. What are we going to hear?

Presenter12:57

Yeah.

Professor Carlo Rovelli12:57

The third piece of music is, I would say, quintessential Venice and uh the culture of Venice is Vivaldi, the allegoretto from uh a concerto for uh violin and strings. And uh I had the incredible fortune at the time of high school of uh I could go once a week in an empty church where there was a group that was playing Vivaldi, that was unknown at the time and later became one of the world famous uh chamber music group, Solis Divinity. And they were rehearsing once a week and we boys from the school would go there and listen to them and it was absolutely magic and it was my entry into music.

Presenter14:46

The first movement of Viveldi's concerto for violin and strings performed there by E Musici led by Federico Agostini. Carlo Rivelli, tell me what age were you when you began to wonder about the world, began to sort of ponder it?

Professor Carlo Rovelli15:02

I have been reading all through my life enormously. In high school,

Professor Carlo Rovelli15:09

I began to dislike school.

Professor Carlo Rovelli15:12

To being in a position of clash against my teachers, not believing what they were telling me and being fascinated by what I was finding in books. I read politics, I read sociology, I read science, I read novels, poetry. There was an incredible space out there to explore, and school was so boring in comparison. And I found myself in a situation of rebellion, and at that point I started to talk to other, and we felt ourselves it was a

Professor Carlo Rovelli15:46

Huge disappointment later, but we felt ourselves as the beginning of a new world, a new reality.

Presenter15:51

You went on as a young man then to study physics at Bologna University, and there is you know, as you were describing it there, this tradition, or there was in Italian academia, of studying across subjects. What difference did your interest and knowledge in, say, the arts and philosophy and music make to the beginning of your studies in physics?

Professor Carlo Rovelli16:11

I went into physics a little bit by chance. I wasn't even sure that I actually wanted to go to university and to study. My dream life was to be a beggar and just go around the world and do nothing, which I did for a while, but then I thought that, well, it wasn't such a great life after all, and I could do better. And then.

Professor Carlo Rovelli16:31

Around my third university year, I was not following the classes at university, I was just studying by myself. While studying for an exam, I started thinking, wow, this is beautiful, this is incredibly beautiful. And more than that, in modern theoretical physics, there is a change in the way we view the world. There is a discovery of new visions of the world that resonated enormously for me to the desire of change, of rebellion, of discovery new things that was driving my life.

Presenter17:06

Let's fit in some more music, Carlo Rovelli. Tell me about this, we're gonna hear your force.

Professor Carlo Rovelli17:11

Avapart is a modern composer who who I love and uh I think it captures this pure beauty which I see in physics. But in particular this piece, Furalina, it's a short uh enchanted uh piece of purity, which for me is like a representation of the kind of cleanness and uh essentialness, the characteristic of being essential and simple, which is in theoretical physics.

Presenter18:45

That was part of For Alina, composed by Arvo Pert and performed there by Alexander Malter. And you said, Carlo Rovelli, that you'd chosen it for its simplicity. And I'm wondering you you've alluded a couple of times, or you've spoken a couple of times as we've been talking today, about the times in the nineteen seventies when you'd experimented with drugs and you went on your own free thinking way, and those sort of liminal areas of understanding that people can experience through drugs. Did they start to inform the work you were doing as well? The idea of sort of going beyond what is simply in front of us and apparently rational?

Professor Carlo Rovelli19:18

Yes, uh n not obviously not in the sense that by taking drugs one finds right physics. That's not doesn't work that way. It doesn't work that way. It would be too easy. Uh but yes, in the sense that uh a lot of science is based on recognizing that things are not the way they seem to be. The earth is not flat and uh is not still, but it moves. And definitely drugs for me and for many people played a role in uh freeing ourselves from uh the belief uh that uh the basic grammar through which we see nature is the only possible one. If one study uh quantum gravity like I do,

Presenter19:25

It doesn't work that way.

Professor Carlo Rovelli19:58

To find uh a correct description of the world in quantum gravity, one has to change the way we think about space, the way we think about time. And uh what is hard is to accept the idea that our obvious perception of space and time might be wrong, in inappropriate for studying things in the very small and very large

Presenter20:20

Large. Tell me a little bit more about this hippie commune in Umbria and living with the goat called Lucretia. I read about that and I immediately wanted to know a lot more. Um how did you find living in a commune? Did it suit you?

Professor Carlo Rovelli20:32

It never sued anybody living in a commune because it doesn't work, but it was but nevertheless it was a fantastic experience and I remember it as one of the defining periods in my life. And I was just feeling free and wandering and discovering. And in fact, I was beginning to study physics there. People laughing at me. I had huge rolls of paper and writing equations after equation after equation under a tree. And a lot of physics that I studied, I studied there.

Presenter21:02

You mentioned earlier on that we thought this countercultural thing would would work out and be a great idea. Turns out not so much. What was the point at which you embraced a degree of convention in your life?

Professor Carlo Rovelli21:14

The late seventies in Italy was a particularly hard moment for all the young generation. There was a disappointment, a strong disappointment. We are not going to change the world. The world is much harder and stronger. And very simply, the majority of the people of this planet does not want to change the world the way we want. So that's fine. I mean, that's what people want. So at that point, I felt a bit disoriented. Where do I go? And I think a lot of intellectuals are born from that sense of what is my place in society. And being an artist, being in science, being in theater is a perfect way out because society allows more freedom to these people. And when I discovered how beautiful this theoretical physics, and I also discovered that I was good at it, which was a late discovery, some of my teachers at university scolded me and said, Come on, Carlo, you can do this stuff. Then I had a moment in which I thought, well, maybe I can be a theoretical physicist. And I went into it full energy.

Presenter22:20

More to come. Tell me about your fifth disc. What are we going to hear now?

Professor Carlo Rovelli22:25

Well, we are really going back to that hippie world with Jerry Garcia and this music which I heard the first time in a movie by Antonioni. It's a Brisky Point. It's a movie set in the California of the late sixties. And in the m movie at some point there is a sort of surreal scene where the two characters make love in the desert and suddenly the desert fills up with couples making love in a joyful, happy light way. And you know, me coming from Italy, repressive Catholic, closed sex is bad, this lightness of love was marvelous.

Presenter23:43

Love scene, Jerry Garcia. So, um, Carlo Rovelli, in 1987, then, you took up a post-doctoral position at Yale.

Presenter23:49

And around about 1988, together with your colleagues there, you introduced a theory, and that theory was called loop quantum gravity. Now, as I understand, I've got my notes here in front of me, and I'm going to try and explain how much of it. So, this theory tries to reconcile general relativity, which most people of course are familiar with, the theory of gravity as it applies to large entities like planets, with quantum mechanics, which we've already touched on, and we've touched on how difficult that is. And that's the theory of gravity as it pertains to the smallest things, to particles and so on. Am I right? Perfect.

Presenter24:23

Right. So fill in the important spaces then. What was the work that you were trying to do to reconcile these two things?

Professor Carlo Rovelli24:32

The discovery of gravity is the discovery that space it's like a physical entity that can bend, has its own dynamics. Space moves, space can stretch, can compress. We saw last year the discovery of gravitational waves, space itself waving like the surface of the sea. And quantum mechanics teaches us that all waves, all things that move, have a quantum structure, which means a discrete structure. They're made by little bricks, little dots, little packets, like light, for instance, made by photons. So our theory, the theory in which I've been working with my colleagues, quantum gravity, tries to study the bits, the grains of that space itself should be made of. So we are immersed in a space which not only bent, but has a granular structure, has a minimal structure, which is like dots of space, which are not in space, they are space themselves. And so we wrote equations describing how these bits of space move and interact. And why is this important?

Professor Carlo Rovelli25:38

It's important for a number of reasons. First of all, it's an attempt to bring this seemingly incompatible pieces of our understanding of the fundamental world together. Second, because it tells us what is space in the small. And third, because it fills in a number of open questions which we don't know how to answer, like what happened at the beginning of the universe or what happens in the center of black holes. The theory of the Big Bang doesn't say that the universe started at the Big Bang. It says that the universe started in some very s compressed and hot state in which all the galaxies were squeezed in a small region. But what happened at that point exactly, we don't know. We need a quantum theory of gravity.

Speaker 326:17

So

Professor Carlo Rovelli26:23

to find out. So our theoretical work is meant to provide the the basic th theoretical understanding, the conceptual tools to be applied to that particular situation, where space and times are not going to be the space and time we are familiar with, they're going to be different.

Presenter26:39

Yeah.

Presenter26:40

Some more music, Cardo Rovelli. Tell me about your next. This is your your sixth piece.

Professor Carlo Rovelli26:46

Oh, that's Bach. That's a marvelous small little piece of a Bach cantata. And I remember distinctively I was in uh high school, I was at a party with some friends and a friend of mine came to me and said, You're gonna like this one and put some um headset around my ear and uh these two voices, pure joy, started singing and since ever I keep hearing this piece of music.

Professor Carlo Rovelli27:24

Yeah.

Presenter28:19

That was part of the second movement of Bach's Jesus, You, Who My Soul, performed there by Theresa Stitch Randall and Dagmar Hermann, accompanied by the Vienna State Orchestra and chorus conducted by Felix Prohaszka. So tell me, Carlo Rovelli, when you are not working, what occupies your time?

Professor Carlo Rovelli28:37

I have a small boat, it's a hundred years old, uh five six meters, with a sail next to where I live, so I sail in the Mediterranean, going out and swimming in the sea. I travel a lot, travel with women I love.

Presenter28:52

Who's also a theoretical physicist, as well as the

Professor Carlo Rovelli28:54

Right. That's right. I I keep reading, especially novels and old novels, and I spend time with my friends.

Presenter29:01

Do you ponder on the meaning of life? I mean, does your work give you meaning? Do you feel like the meaning of your life has to be the knowledge that you hand on?

Professor Carlo Rovelli29:09

Uh I often ponder about the meaning of life. I think we all do. I get to the point in which uh I think that uh we all of us are full of meaning of life and we don't need to search for one. Before being rational, I think we are animals and uh humans and social beings uh full of desire, full of motives. So I don't think we need meaning of life. To the opposite, we have to resist the excess of meaning that come from inside ourselves. I think that life is short, is finite, there's nothing after it.

Presenter29:46

There's nothing after it.

Professor Carlo Rovelli29:47

Yeah, it seems totally obvious to me that there's nothing after it. And uh that's why it's precious, that's why it's beautiful, that's why it's fantastic.

Presenter29:47

Yeah.

Presenter29:54

It's interesting. You seem very definite on that. And yet, throughout the morning, as we've been talking, you've said, well, you know, well, this is what I think and this is what it looks like and it may be this and yet you've just said, No, there's there's no there's n there's no afterlife. You seem very definite on that.

Presenter30:08

Yeah.

Professor Carlo Rovelli30:08

Well, we do have things we consider pretty obvious and reasonable, even if we are not sure about anything. So I would be very, very surprised if after dying I would wake up and find, I don't know, what, a big old man saying, Hey, you've been good, go that way, you've been bad, go that way. No, I don't believe so.

Presenter30:28

Tell me about your next piece of music, then what are we going to hear next?

Professor Carlo Rovelli30:31

Next one is Imagine by John Lennon. It's a simple, sweet anthem of a generation and the world so many of us dreamed, quite different from the present world. A world where there are no boundaries, there are no separations, there's no war, and when somebody kills us, we don't react by saying, Okay, let's kill all of them, but we react by saying, Well, let's talk and stop killing one another.

Speaker 431:02

Imagine there's no heaven.

Speaker 431:07

See if you try.

Speaker 431:15

Blue hell

Speaker 431:16

Below us.

Speaker 431:22

Above us only sky

Speaker 431:27

Imagine all the people.

Speaker 431:33

Bivin

Speaker 431:35

Fall today.

Presenter31:39

That was John Lennon and Imagine. I wonder, Carlo Ravelli, do you think as a theoretical physicist there is a point I'm sure you work with with young students often enough to have an idea about this where you feel that you will hand on

Presenter31:52

The work that you have done, or do you think you will do it until the day that you turn up your toes?

Professor Carlo Rovelli31:57

You're touching something that uh worries me like now, because uh there is a point in life in which you say, Well, am I risking of being counterproductive by being older and uh having an influence on other lives? Is my influence positive or negative at some point? I mean, I've uh I've been struggling against old people in my youth and now I'm definitely on the other side. So there is a great scientist that answered a similar question, say, Well, you can keep doing your stuff provided that you don't impose it to the young

Presenter32:31

I'm trying to go this way. You know, I'm going to send you off to this island because you're being cast away today. First of all, what are you looking forward to? I love.

Professor Carlo Rovelli32:37

Yeah, true.

Professor Carlo Rovelli32:41

I love being alone. I love uh silence. Of course being on a desert island means being away from the people you love. I I think that's a horribly hard part. But the price of being uh alone in the desert uh it's uh it I think is priceless. It's fantastic. I I I look forward

Presenter32:58

For the island, time for your final piece of music, Carlo Rivelli. Tell me about this. What's your eighth?

Professor Carlo Rovelli33:04

The Crystal Ship, Jim Morrison, The Doors. It's a marvelous piece of music to which I often go back. I have had a rather stormy life. I've changed the countries many times, I've changed a lot in my life. This is so mm dreamy and it's about sleep, about maybe death, about being elsewhere. It's soft, it's sweet, and uh Jim Morrison's voice is so wonderful. It's about elsewhere.

Speaker 433:35

But days are bright and filled with pain Enclose me in your gentle rain

Speaker 433:47

The time you round was two when Sally will meet again.

Speaker 433:59

Will meet again.

Presenter34:08

The Crystal Ship, the Doors. So, Carlo Rovelli, I give all my castaways a couple of books to take with them to this little island. They get the Bible, and they get the complete works of Shakespeare, and they get to take one other book, too. What's yours going to be?

Professor Carlo Rovelli34:22

Yeah.

Presenter34:22

Homer the Odyssey?

Presenter34:24

Right. That's yours. Yeah. And also you are allowed to take a luxury.

Professor Carlo Rovelli34:26

Yeah.

Presenter34:30

I would take a telescope.

Professor Carlo Rovelli34:31

Uh

Professor Carlo Rovelli34:32

Ah. Because the night on the islands will be long and I'm sure the telescope will fill them entirely and open an immense space. The island is small and the sky is immense.

Presenter34:38

And

Presenter34:42

Okay, we shall give you that. And if you had to save just one of these discs from the waves, which one would it be?

Presenter34:50

It would be

Professor Carlo Rovelli34:51

Jerry Garcia, because uh it's a music that uh doesn't start, doesn't end, it cannot be exhausted and uh is soft and sweet uh and will be wonderful to play.

Presenter35:01

Well, it's yours then. Professor Carlo Rovelli, thank you very much for letting us hear your desert island discs. Thank you, Cassie. Thank you very much.

Professor Carlo Rovelli35:01

Yeah.

Presenter35:54

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Speaker 436:25

This is the BBC.