The Infinite Monkey Cage - Glastonbury

Episode Date: July 1, 2013

Brian Cox and Robin Ince transport their cage of infinite proportions to the Glastonbury Festival as they take to the stage with their special brand of science and comedy. They are joined by singer KT Tunstall and physicists Fay Dowker and Jeff Forshaw to discuss all things Quantum, in the most unlikely of places!

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To find out more, visit bbc.co.uk slash radio4. Ladies and gentlemen, would you please, for Glastonbury 2013, put your hands together, go absolutely wild with applause for Robin Ince, Brian Cox and the Infinite Monkey King! Yay! So basically what happened was we did Glastonbury two years ago and they asked us to do it again and Brian said, well if we're doing Glastonbury why don't we do something simple and gentle

about poetry or why stars are pretty and I said, no! We have got an audience of people who will be quite confused by this stage of the festival. Quantum cosmology is the only idea, and you are the perfect audience for quantum cosmology because I believe you are displaying quantum behaviour. Many of you are both dead and alive.

You are here and you are not here. You are indeed all in super positions. Yes, today we'll be looking at quantum cosmology. Are time and space, as Einstein envisaged, a smooth fabric with the future as real as the past? Or does quantum theory save us from deterministic drudgery? Are there really an infinite number of parallel universes, or is this it? What happens inside a black hole?

Was there anything before the Big Bang? Is there a possibility that I might one day meet another me from another world where I am shorter, without my trademark good looks and great hair and with no real understanding of particle physics at all? And am I that? Am I the other Brian Cox?

Have I come here to this world to kill him in some kind of Philip K. Dick nightmare? So, to help us explain, and when I say us, I do not include me, because I have no idea. We were actually up last night talking about these ideas, and they are fantastically bamboozling. Our first guest is a professor of theoretical physics

at Imperial College London, where she specialises in quantum cosmology. She has never been to the Glastonbury Festival before, but as someone who's studied many world interpretations, she also knows that she has been to every single Glastonbury Festival before, but as someone who's studied many worlds' interpretations, she also knows that she has been to every single Glastonbury Festival before. Sometimes as a human, sometimes as a sentient droplet of pear juice. She is someone dealing with very confusing worlds. It is Faye Dauker. Our next guest works on the phenomenology of elementary particle physics.

And trying to say phenomenology without thinking about the Muppets is difficult. Try it, phenomenology. Do-do-do-do-do. Thank you. He's also co-writer of books with a popular TV scientist, such as Why Does E Equals M C Squared and The Quantum Universe. It is Professor Geoff Foreshaw. It is Professor Geoff Foreshaw.

And like so many of our regular guests, Professor Richard Dawkins, Sir Paul Nurse, and the Astronomer Royal, Sir Martin Rees, today one of our guests is also a former podium dancer like them. Richard Dawkins, of course, used to be a podium dancer at the Heaven Nightclub until a falling out after their refusal to change its name to a finite existence followed by an inevitable death without any sense of being nightclub

he's a regular on Have I Got News For You The Now Show and sometimes also goes under the name Giles Wembley Hogg and he is Marcus Brickstar and our final guest is a musician who we had to have on because she titled her albums Eye to the Telescope and Crescent Moon and became a musician despite being brought up in a house with only one album in it, but it was satirist and scientist Tom Lehrer,

so that's a good start. You might hear more of that later. It is the great KT Tunstall, and this is our panel. CHEERING AND APPLAUSE later. It is the great KT Tunstall, and this is our panel. Now, I thought we'd start, because we have two of the most eminent professors in the UK here, Professor Fedayevka, Professor Geoff Foreshaw, I thought we'd start by getting a feel for what quantum cosmology is and the ideas behind it. So, Marcus Bridstock, quickly, can you explain quantum cosmology in a minute? In a minute? Yes, I certainly can. Is that with

deviation, repetition and hesitation? And can the benefit of the doubt go to anybody but me? Yes, I can explain it perfectly simply. If you go to the top of the Glastonbury Festival, by top, I mean the highest point here, you reach the green fields and then you can look down on the entire Glastonbury Festival and that in a way is probably the best metaphor in this short amount of time that I can think of to explain the thing

that you asked me about. And another thing that is worth remembering is that on the way back from there you can pass through what's known as the healing fields or what I like to call the field of lies. They're very sweet lies. They're lovely.

They don't mean any ill, but it is simply a field of lies. Ah, I see you're wearing spectacles. Rub these on them. You can't fix my eyesight like that. Lovely people, though. Katie, you were actually, your father was a physicist.

You were brought up in a house there. I'm here entirely vicariously through my father. So what was it, in terms of your experience with your father, trying to explain some of these kind of incredible ideas? Well, my dad loved his job, so he was just in the lab all the time. But he kind of played games with me and my brothers when we were little, and his favourite one was

the liquid nitrogen came in a big canister on a kind of dolly trolley, and he'd take the liquid nitrogen off, put me and my brother on the trolley, slush the liquid nitrogen down the corridor, then put me and my brother on the trolley and go, don't touch! And push us down the corridor, then put me and my brother on the trolley and go, don't touch, and push us down the corridor. And it was amazing. And social services never

found out about it. So, Faye, we've got these two words, quantum cosmology. So if you could start by just describing what cosmology is as a subject. Cosmology is the study of the whole universe all at once. So that does indeed include all of Glastonbury, everyone in this tent, absolutely everything. That's cosmology. But that's incredibly difficult. We couldn't possibly, in practice, explain everything all at once. in practice explain everything all at once. So what we do in cosmology is we ask questions about the largest scales in the universe that we can see.

So when we look out in the universe, we see that our sun is just one of 100 billion stars in our galaxy, and each galaxy, our galaxy, is only one of 100 billion galaxies in the observable universe. The most important and interesting thing that we see when we look out and we see all these galaxies is that they are moving away from us. The universe itself is expanding,

and it is expanding at a tremendous rate, and we know that, therefore, in the past, The universe itself is expanding, and it's expanding at a tremendous rate. And we know that, therefore, in the past, the universe must have been a lot smaller than it is now. Sorry, I have a question. Is the universe likely to keep on expanding and expanding, or is it like UKIP, and we hope that that's sort of a blip? We don't know the answer. It sort of gets bigger for a bit, and then people go,

oh, that's just silly. We don't know the answer to that question completely, but on the evidence that we have right now, the universe is... The expansion of the universe, its rate is actually increasing. So the rate of expansion is accelerating, and if that continues, then it will expand forever. We're living in a Farage universe, is what you mean.

It's Farage. If you're that anti-European, it's Farage, not Farage. Farage. Farage as in garage. Geoff, so why do we need quantum ideas? Why do you need those ideas in explaining? Why is classical ideas of physics not enough to explain the basic ideas of this universe, of our universe?

Well, in large part, classical ideas are OK. When you're building bridges, you don't need to know about quantum physics. But to understand how atoms work, then it's absolutely mandatory. To understand how the tiny particles which make up all of the things in the universe, as far as we can tell, everything in the universe is made up of tiny particles, things like electrons. Then to understand how those particles behave, we have to introduce these new laws, these laws of quantum physics. And these laws are characterized by the fact that they are ridiculous. They're a complete affront to common sense. So they have you...

We're back at UKIP. So you would be thinking about how an electron is behaving in the vicinity of a proton. That's a hydrogen atom. And the correct way to describe the electron in the vicinity of the proton is to suppose that that electron is in several different places at the same time and again in order to embrace ideas like particles a single particle can be in two places at once it's about as mind-blowing as it gets and the cosmology project is really audacious as faye was saying this is an attempt to describe the entirety of the universe starting out at the very beginning and it's so audacious that we're pretty certain that we can understand the evolution of the universe from a point

when all of those billions and billions of stars were compressed into a volume about the size of a beach ball. So all of that at the size of a beach ball. From there on to the present day we're reasonably confident that we actually understand the physics quantum effects come in before then earlier on we come across quantum physics in cosmology when we get to the very early universe much smaller than a second tiny tiny fractions of a second. That's been quantified. That was beautifully explained. Can I just say what is lovely is there's a wonderful silence in the audience,

and I know that all of them have at least grasped that at one point the universe was a beach ball. And then there's kind of that. We know that. We know that for certain. Can I just check? That time is an equation. I mean, what time frame are we talking about, from the Big Bang to the universe being the size of a beach ball?

It's something like 10 to the minus 25 seconds. Katie, to summarize that, we have, what, billions, 350 billion or so galaxies in the observable universe, large galaxies, compressed into the size of a beach ball. And the claim, Jeff's claim, the claim of modern physics, is we understand things pretty well from that point. The rest of this programme is talking about the universe before it got as big as a beach ball.

What do you think? Well, what fascinates me, the very little that I know about quantum mechanics and quantum physics, is that it basically seems to be that very little things don't necessarily like being looked at, and they sometimes behave a bit naughtily cheeky but shy particles there was there was actually you might like there was no it used to be an idea uh called pan psychism which was that even the smallest particles actually had

consciousness right which i know is one of your famous i love it i liked it. I liked that idea, till I then imagined the Large Hadron Collider, and it became really melancholy. Just where are we going? Round and round and round. Then it's the end. All this used to be fields. I bet there's a really keen particle at CERN, though, going, isn't it fast, though?

You go fast. The Jeremy Clarkson of particles going, I went round the collider. One of those particles is going, let's break it again. This is the rational tent. I'm not having this kind of conversation in the rational tent. You're looking for the left field, Brian. This is a tent full of nonsense.

But that is... I mean, Katie, you've said in an interview recently that you actually, when you were writing your new album, you were thinking very specifically about quantum ideas, and that you did actually kind of... Well, I wouldn't say very specifically, but I think, but with hindsight, which is a good thing in quantum physics, that I wrote the first half of my album, and I was concentrating on sort of smaller things,

and within a few months, there was a really weird sidekick quality to the first half of the record, where the songs that I'd written were incredibly informative of things that had happened afterwards and things that I couldn't have predicted happening. And Hal Gelb, who I made the record with, is a real firm believer also in the subconscious,

having very often a stronger effect on the way that you can think than your conscious mind, that there's something at play that is of your nature that you're not actually in control of and that is working on a more mysterious level than your conscious brain is. And the thing that I think for me, knowing very little about this, is the information, which might be completely wrong, that our brains are taking in

400 billion pieces of information a second, and yet we're actually only capable of processing... Three. Yeah, four. 2,000 or something. So our brains are choosing the reality that we're experiencing. I think Jeff was suggesting, so in particle physics,

it's what both myself and Jeff do, there seems to be no real conceptual problem in thinking about an electron doing multiple things at once around a proton, or at least it doesn't make us particularly uncomfortable. But when we move on to the universe and building a quantum picture, a quantum theory of the universe, are we really saying that we can legitimately think of multiple universes with multiple things happening? Or is that a signal that we don't understand physics correctly when we talk about quantum cosmology? There's controversy on exactly that question.

Quantum mechanics was invented, it was discovered to describe small things. And in trying to apply it to the whole universe, we have to do something that quantum mechanics isn't set up to do. So the rules of quantum mechanics tell you how to make predictions about observations and measurements that you make on the quantum system. And as you say, when the quantum system is an electron, then you're not too bothered about exactly what that electron is doing. You can use fuzzy language and say,

well, maybe it's in lots of places all at the same time. Maybe it's here and here at the same time. When it's just an electron, that's not too bothersome. But when you're talking about the whole universe, there's nothing outside the universe to measure or observe us in the universe. We, we're all part of the universe, and we are supposed to be part of the quantum system when we do quantum cosmology and the rules of quantum mechanics are just not set up for that situation they're not set up to

tell us what's really going on in a quantum system and there's just different points of view in the scientific community amongst physicists about how to describe what's really going on in a quantum system quantum physicists i'm interested in the the multiverse theory do serious quantum physicists and i imagine most of you are fairly serious spend time thinking a lot about the multiverse thing because it strikes me that it's a sort of it's a campfire greenfields bit of nitrous discussion. Yeah, you know, there could be a you and me over there. But it's sort of, considering it, does it have any practical effect on our understanding of this reality?

Have you seen sliding doors? Did you cry? The answer to that is yes. There are lots of serious physicists who take seriously the idea that there are multiple universes. It's very hard to test it, so they get criticised a lot for doing stuff which is not really physics because they need to think of a good way of testing that idea, a way of doing an experiment that would indicate that they're not just crazy.

And so far, there have not been any experiments like that. The kind of test that we would like to do would be, if you imagine getting out of bed in the morning, you could get out of bed on the left or on the right. So there are two versions. They're intense, mate. They're mostly intense. You can kind of roll out of the sleeping bag to the left or to the right and then go about your business.

And then at some point in the future, you make some decision or other. And the question of whether or not... Is there a universe where you got out on the left and one where you got out on the right? And if so, do they make a difference to your future? That's the kind of experiment that people are trying to do with things, not people, but much smaller objects. You've made it sound like physicists for years

have been trying to get out of bed and realising that the safest thing to do is to remain in it. So, Jeff's describing this interpretation of quantum theory as applied to a universe in which there really are multiple, actually infinite number of instances of all of us all interfering together, an infinite number of instances of all of us, all interfering together, an infinite number of universes. Is that, and Jeff has said that people take that seriously.

What's your view on that kind of interpretation? So I don't take that point of view. There are people who take that seriously. We're all struggling to understand what it means for the whole universe to be a quantum system. And this is one direction that people have taken that hypothesis in. I don't think that. I think there's just one instance of the universe.

There aren't multiple copies of us. There's just us. But we still have to understand how to describe ourselves quantum mechanically. That's work in progress as far as I'm concerned. The answer isn't we don't know we're doing research to figure out what what it means for us to be quantum systems and in doing quantum cosmology that that's one of the challenges to understand what it means for the hope for the universe to be a quantum system to describe the universe in fully quantum terms without having to mention or or pay regard to

or assume that there's something outside the universe looking at us. So in ourselves, being quantum systems, we want to be able to describe that. And the second challenge in quantum cosmology is that we need to be able to understand what it means for space-time itself to be quantum. So in cosmology, as Geoff was describing, there are two things. There's the matter in the universe, and we know that's quantum. As Jeff was saying, we have very good quantum theories to describe matter,

which we test to supreme and beautiful accuracy in experiments like at the LHC. But there's also space-time, and according to general relativity, Einstein's theory of gravity, space-time is itself a thing. It's just as real and material as the matter that this table is made of. And space-time bends, it warps, it ripples. It interacts with the matter. So the matter tells the space-time how to ripple, how to warp, and the space-time tells the matter how to move.

And because the matter is quantum, we know that there must be quantum fluctuations in space-time itself. But throughout most of the history of the universe, we can assume that those fluctuations are small enough we can just ignore them. However, at the Big Bang, at that moment, the quantum fluctuations in space-time are so big we can't ignore them anymore. General relativity itself breaks down

and we need a quantum theory of gravity. We need to know what the quantum structure of space-time is. And we're talking about, what, 10 to the minus 42 seconds after the Big Bang now, isn't it? So that is, for the drinkers, a million, million, million, million, million, million, millionths of a second after the Big Bang.

That's what's worrying us at the moment, the physics before that time. Physics before that time. And many scientists working on this problem of finding a quantum theory of space-time or a quantum theory of gravity, because according to general relativity, gravity is a manifestation of the curvature and warpage of space-time. Many people working on this problem think that at that time, or before that

10 to the minus 42 seconds after the Big Bang, Space-time ceases to be a smooth and continuous fabric, but is better described as something which is granular and atomic. I mean, I don't mean it's made of the same atoms that tables and chairs are made of, but it's made of individual grains, individual pixels, if you like. And that's a general idea that many people are pursuing. Just to underline how strange that is, you're talking about time here. So time itself and space together as space-time being granular

and built up out of indivisible units of time. Exactly. So what you experience as the passage of time is, or could be, according to these ideas, it could be the coming into being of these individual grains of time. Sorry, I've got another question. Because we've had the universe was lumpy and time granular. Are these words that you're using to comfort us, the simple, the tired, and the stoned? Or are those convenient descriptions for things that are massively complicated,

or are they genuinely how you see it? Little tiny pixels, particles, granular, and that the beach ball of everything was lumpy. Yeah, it was lumpy. It is lumpy. That's science there. It does make you feel better about your sleeping bag on a Sunday. Yeah, it is lumpy and granular, but in many ways isn't that the beginning of a universe in itself?

My mattress is simply full of everything and time. Katie, Richard Feynman, the great physicist, he once said, anyone who says they understand quantum physics doesn't understand quantum physics, which is obviously a tremendous relief for Marcus and me. Yeah, hello. What do you feel, for you as someone, again, who's not a scientist but brought up in a scientific family,

what are the hardest problems? What is the point where you go, now this bit someone, again, who's not a scientist, but brought up in a scientific family, what are the hardest problems? What is the point where you go, now this bit is too counter-instinctive? I mean, my poor dad used to come home from work and he'd go, look at my graph! And we'd go, shut up, Dad. Sit down, have your dinner. And so I do wonder whether our... And no disrespect to any scientists who are here, but is there some things that human beings cannot yet understand? And obviously people who are specialists in this field

are able to grasp it using language that is used in a way that we don't use it, granular, lumpy. But there's parts of it that I think that you can grasp onto something like entanglement where you've got two particles they're separated by a vast distance you do something to one of them and this exact same thing happens to another one and that that's a very kind of human fantastically human thing to grab onto the fact that our ideas of time travel or or um you know it's impossible that that's kind of an instruction that's going that distance it has to be something that's happening beyond someone someone like my grasp but that is surely

proof of some sort of subatomic connectivity, molecular connectivity, that does apply to us. It's what we're made of. And it surely informs us that there's connection between things in this universe that we don't understand, and that when you do separate things from each other, it doesn't work, that the universe isn't necessarily working as a machine, it's an organism. It's interesting. Katie raises a point there

about perhaps the limits of human understanding. We're assuming that we should be able to comprehend and understand the universe as it was, as you said, when it's millions and millions of times smaller than a beach ball, in fact. The observable universe is the tiny, microscopic, subatomic thing. Is there any reason to have confidence that we can actually begin to understand and answer these questions, or could it be that we just reach a limit?

Well, what should be said, first of all, is that... I mean, it sounds very grand, as though there's some attempt to explain lots of things, but actually everything that Fay and I have been talking about is characterised in large part by its simplicity and the fact that, for example, that nascent beach ball universe was actually less complicated than understanding what happens when you kick a bucket of water.

The physics of the universe when it was very young was remarkably, as far as we understand it, remarkably simple. Likewise, the stuff that's going on at CERN involves taking one or two particles and just banging them into each other. The rules are straightforward, and we can apply the rules so we can understand how these little particles are behaving. Put that way, it doesn't sound very ambitious.

So one thing that fundamental science is not capable of doing is explaining complicated phenomena complicated things how complicated things behave that's another branch of science which which is growing in interest the study of complicated systems so this fundamental physics it's all about getting our basic ideas right about what the fundamental laws are that are in play in the universe. It's a far cry from understanding those fundamental laws. We can have the fundamental laws, but we still won't be able to understand

a large fraction of the things that happen in the universe, especially those characterized by complicated things, things with lots of atoms in them, for example. It's a bit like knowing the rules of chess. You can know the rules of chess, but that doesn't mean that you can play chess like Garry Kasparov. So it might sound sometimes like it's a very ambitious program, and in some ways it is, but it's not.

In other ways, it's extremely simple and limited in its scope. Was quantum cosmology, did this happen during a kind of physicist beach holiday? We've got beach balls, buckets of water, granular, and do you ever get worried that with some of these ideas that, will there be a point, like we just said about Feynman, anyone who says they understand quantum physics doesn't understand quantum physics, do you ever have moments of doubt of going, what if we've gone down entirely the wrong path?

What if it does turn up? What if there is a moment of discovery where suddenly you go, wow, this could not... Or do you feel a level of confidence with it? Well, I mean, it would be wrong to say that I would be really happy if it turned out that everything that I've been doing was totally wrong. But there's a side of me that would welcome that in that there's a lot of stuff that I don't understand and that's

what allows me to get excited about carrying on doing physics. I want to understand how things work and the understanding that we've got now of how tiny particles behave, these quantum rules, which by the way are not esoteric. I mean they're the rules that determine how silicon chips work and how the micro, the transistors that are inside of them, present in their billions how they behave and so these laws are really tangible, you couldn't

design a computer without them but I've lost my train what was just say, are you alright right, Glastonbury? That's what you do. You'll be all right. Is there ever a...

You know, you have Newtonian laws that work up to a point. So is there any moment where you think, will there be another discovery which will turn much of this? So the fact that we can understand so much with so little, because that's the characteristic feature of what we've got. We've not got many equations that we write down. It's not like a big encyclopedia that we need. Just a few equations describe so much of the universe.

It really feels like we've got some measure of understanding. It's hard to imagine something taking that away from us. It works and is useful to people. So any new ideas may completely upturn the way that we think about the fundamentals, but they're not going to change the stuff that we've got already. It's a bit like when quantum physics came along. It completely overturned everything that Isaac Newton had done fundamentally, but all the bridges didn't suddenly fall down when we discovered quantum physics.

So we get better and better at understanding nature and surely we don't understand it all yet. There's more and it's in that sense that it's exciting. You're quite a young man. What do you think you'll do once you've solved it? After this, once you've got

it all and someone's noted it down and that, what next for you? I've got two young kids. Oh, right. Well, that's you buggered then. Faye, I wanted to... Geoff said that about new ideas overturning old ideas. This happens in physics from time to time. But you spoke about this idea of space-time itself being built up, in a sense,

these grains of space-time itself being built up, in a sense, these grains of space-time being constructed, as though the idea that the future is not yet there, that it has to be constructed, is a new idea and a challenging idea in physics. So what is the current paradigm? Because I think it seems to many people that the idea that the future is yet to be built seems to be a natural idea.

So our best theory that the idea the future is yet to be built seems to be a natural idea so our best theory of that deals with the question of the nature of time is general general relativity that's einstein's theory of gravity it's a theory there's no such thing as a global universal moment of now that is the same for us here for me for you for everyone in the rest of the site for people in sydney and australia for people on mars for aliens elsewhere in the universe. There's no such thing as now that covers the whole universe. That's simply an unphysical thing to think. And the way that Einstein described that is he said that there's relativity of simultaneity. So we can all say that together, but maybe I won't make you say it.

So there's no such thing as there being simultaneous events everywhere in the universe that we can all agree are now. Is that why Live Aid didn't work very well? And because there's no now, that means that now is what divides the past from the future. So because there's no global now, there can't be any difference between events in the past and events in the future. They must be just as real as each other, because now is what divides them. So if there's no now, there's no distinction

between past and future. And so people have taken this to its limit and said, well, that means that the universe must exist as a block. Or everything that has happened, everything that will happen, all those things exist in a timeless way, laid out once and for all in this block. And it is called, in fact, the block universe point of view. And people who believe that are called blockheads. This is great because Robin can ask the question that he's tried to ask for eight series of Monkey Cage. He sits there and he wants to ask the question but what about free will?

No, I'm never interested in free will. If free will's an illusion, who cares? He asks it all the time. It doesn't matter. It gets edited out of every show that we do. Go on, ask it. I'm not interested. Do you want him to ask it? I'm going to find out. Go on, Robin. I'll tell you what, I'll ask me a question.

Thank you very much. I like working with Eddie Large. So it's... Could it be true that free will's an illusion? Yes, but only if you need... That's all I needed! But this is one of the the things I do find interesting, we talked before about quantum ideas

being possibly a gateway to Boulder Dash. You were saying, Marcus, you were up in the healing fields. Is there a possibility, a problem, where you have people go, ESP can be explained because the mind, a thing, quantum behaviour.

Well, you can, can't you, with a small amount of information but some big sounding words, you can convince a lot of people of some things that certainly aren't true, I've built a fairly successful stand-up career on precisely that but just to

come back, Faith, to the idea that there isn't a now that's one of those things I've heard you say that in silence, I thought right, yes, well the idea that there isn't a now. That's one of those things you hear. I've heard you say that in science. I thought, right, yes, good. Well, she knows what she's talking about, so that must be true. And then I thought, no, that makes no sense to me at all.

I don't get it. Is that because, as you were saying before, time is bent and... I don't understand. I can't even frame a question to explain the way in which I don't understand. That's just going to be edited perfectly. Is it because time is bent? Thank you. Yeah.

The key word is universal. Universal no. So my no exists. I can talk about something no for me, but some things that are in my future will be in somebody else's past. So there's a blurring of the no when we start talking about everything that's happening in the universe, things that are happening far away or close by, that the order of things can be dependent on who's ordering the events.

Obviously, this is limited to human or maybe just animal experience, this idea of a now, because a now is a thing that we experience. But our nows, your now and my now, and the now of a man perhaps called now in Thailand. I don't know what sort of names they use, and I think that might have been racist. I'm not sure. It's perfect balance. Earlier you mentioned UKIP and Asia. And now I'm racist.

You're more pro-UKIP, so it's a good balancing. But all of those nows could happen all at once in the same now, could they not? Not according to general relativity. Those nows, they can't be joined up into a global now that's physical, that has any physical relevance. But what Jeff said is right. There are personal, individual nows which we experience.

So the temporality of our experience, I think, is real, but it's not in general relativity. That's the thing. Our current science doesn't contain any notion of the physicality of our temporal experience, the fact that we experience time passing. We don't feel that we exist once and for all. We feel that there is something special about now.

And one of the ideas that's coming out of this proposal, this hypothesis that space-time is fundamentally granular, is that there's now something to hang physically this experience, this temporality of our experience onto, and it is the process of the coming into being of these space-time grains. That birth of these new atoms of space-time is something that we can hang our individual, personal, local experience of the passage of time onto.

Am I sometimes on the Now Show? Or is that an illusion? You've just done it on your own, Marcus, that's all. It so often feels that way. Katie, we were talking before about... You've been watching some documentaries about quantum physics and quantum ideas. And when you, having been brought up in a scientific household, how do you try and sieve the kind of things you think,

well, I think that may well be a scientific idea and I think that might be possibly the work of a charlatan bamboos with a new book to sell. You usually look at what the person is wearing. And I always, basically, if there's excessive shaping of the beard, you usually

don't trust them. No, I wouldn't say Jeff's is excessively shaped. It's fairly wild there, Marcus. Mine's pretty loose. And grey on one side and not on the other, so I think... You know, you're not dying it. No, no, no, not yet. That's coming. But I think the left side of my face may be travelling more slowly...

No, more quickly through time... This is possible. ...than the right side of my face and is therefore ageing faster. That's an excellent theory, by the way. Thank you. Your tent will be in the healing field. So why is this side of my face so young? And you'll have your beach ball stall.

So we're just about to run out of time, actually. To begin to sum up then, Faye, where do you see this subject this attempt to bring quantum theory and relativity together uh quantum cosmology where do you see it going in the next few years what are you optimistic i'm very optimistic i think that to answer an earlier question the history of science has shown that every time we've been bold and have tried to understand something, then we've been successful. I mean, it's amazing what we have achieved

in some tiny fraction of the history of the entire universe. So the human race has only existed for a mere fraction of the age of the universe. And we understand so much about the universe and our place in it. It's really thrilling and totally inspiring what we have managed to do so far. And that, I take great confidence and heart from that, and I think that there's nothing we can't understand

if we want to, if we try to. And I believe that these ideas will be fruitful. But they've got to be tested. It's got to make predictions for things that we'll see when we look out and measure light from distant objects in the universe. It's got to have consequences for observation so we can test these ideas. Marcus, do you feel after this 27 minutes you now have a great grasp of quantum cosmology?

Define a great grasp, Robin cosmology. Define a great grasp, Robin. Can you narrow that down to a quantum amount? Do you feel that around a campfire tonight at 4am, you will be able to make people believe that you understand the work both of Einstein and beyond?

I tell you what, Robin, I don't think I will, but I think another me will. And, Katie, final question for you, which is, if we look at the many worlds interpretation, what is the perfect world for you in all of those different ones they split up? Oh, my. I would say 1973, watching Led Zeppelin. Were they? Sweet they kicking men?

So we're going to end on a song, because we should explain, right at the beginning we mentioned that Katie Tunstall only had at home, there was one album, and it was an album by Tom Lehrer, who is an incredible, is still alive today, though he hasn't recorded for many years, a great satirical writer, and a great writer on science as well. And we decided that we would attempt possibly the worst sing-along of all time. One of the most complex pieces. Basically, it's a song called The Elements.

And we're going to see what happens in this world when 3,000 tired and confused people attempt in approximately two and a half minutes to sing a song which includes all the elements, I'm very pleased to say that we have to help us do this someone who is currently appearing at the festival. He's appearing with four puffs and a piano. Please welcome to the stage Roland Anderson!

Come on, Brian, you lead the way. You have a grand musical tradition. CHEERING AND APPLAUSE There's antimony, arsenic, aluminum, selenium And hydrogen and oxygen and nitrogen and helium And nicolene, diamine, neptunium, germanium And iron, melamazium, ruthenium, uranium Europium, zirconium, lutetium, vanadium And lanthanum and osmium and astatine and radium And golden protectinium and indium and lithium, and lithium, and lithium,ontium, and Silicon, and Silver, and Sumerium And this is the frame in Lithium, Beryllium, and Barium

There's Holmium, and Helium, and Hafnium, and Erbium And Phosphorus, and Brassium, and Fluorine, and Turbium And Magnesium, and Mercury, and Lithium, and Magnesium There's Protium, and Scallium, and Cerium, and Zinc And Leprechaun, and Tritonium, and Magnesium, and Tritonium Thank you. from Radio 4's evening arts programme, Front Row. To find out more, visit bbc.co.uk slash radio4. This is the first radio ad you can smell. The new Cinnabon Pull Apart, only at Wendy's. It's ooey, gooey and just five bucks with a small coffee all day long. Taxes extra at participating Wendy's until May 5th. Terms and conditions apply.

In our new podcast, Nature Answers, rural stories from a changing planet, we are traveling with you to Uganda and Ghana to meet the people on the front lines of climate change. We will share stories of how they are thriving using lessons learned from nature. And good news, it is working. Learn more by listening to Nature Answers wherever you get your podcasts.