The Infinite Monkey Cage - The Sun

Episode Date: June 22, 2020

Brian Cox and Robin Ince are joined by a dazzling panel of sun worshippers from actor, comedian and musician Tim Minchin to solar scientist Professor Lucie Green and biologist Professor Steve Jones. They look at how the evolution of life was only possible because of our position relative to the sun and its possibly unique behaviour, and how rare that situation might be across the rest of the universe. They also look at how the sun makes you feel and its vital importance to all creatures, especially snails.Producer: Alexandra Feachem

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Music, radio, podcasts. Hello, I'm Robin Ince. And I'm Brian Cox and this is the Infinite Monkey Cage. Two hosts, three guests in two hemispheres and 220 audience members all sat alone in their homes but all gathered together by technology. The future moves on at a pace. We're getting closer and closer to this being the equivalent

of Star Trek's holodeck. In fact, next week we are hoping that our guests are going to be Isaac Newton, Marie Curie, Socrates and Genghis Khan. Genghis Khan? Yeah, I think it's going to add just a little bit of an edge to the show. Anyway, with only around five billion years before it swells

into a red giant and consumes Mercury and Venus, we thought it was time to discuss the sun. To discuss how the nuclear fusion of hydrogen into helium has nurtured life on Earth on sombrero sails, we are joined by a biologist, an astrophysicist and a lyricist, and they are... Hi, I'm Lucy Green. I'm a professor of physics at UCL, and the fact that I think everyone should know about the sun is that even though light only takes eight minutes to get from the surface of the sun to us, that journey from the core to the surface takes 200,000 years. Sunlight is as old as modern humans are. Hi, I'm Steve Jones. I'm a biologist, a geneticist, and I've been working on snails and the sun throughout my entire career and the thing I find most fascinating about the sun I lived in Edinburgh for 10 years and I only

saw it once I'm Tim Minchin I'm not a professor of nothing my favorite fact about the sun is that the sun contains 99.9 percent of all the mass in the solar system and when it has burnt all its fuel the sun will collapse into a white dwarf which will be only about the size of the earth but will still have the mass of 333 000 earths and it will be doing no fusion which means it will be extremely dense like donald trump whilst having no original material like me. And this is our panel. I would like to immediately congratulate Tim Minchin

for the most scientifically accurate satire that we have had all series. There was a lot of information there. That was good. I like it. I like how that that joke like the sun eats itself and also like the sun isn't very funny but is um is donald trump is donald trump supported by electron degeneracy pressure see tim you've walked into one of the traps of science jokes is brian will always then have supplementary questions and you'll go i haven't done the revision beyond that punchline, mate. That's as far as I've gone. Lucy, we're talking about the sun.

So could you give us, to begin with, maybe the one-minute biography of the sun, a description of our star? Yeah, so the sun is the object that I spend my time studying. For me, it's just the most interesting and most important object in the whole solar system in fact a whole universe I would say but it is a fairly typical star in some senses so it's our local star size wise it's about 110 earths lined up side by side surface temperature around 6000 kelvin but in the atmosphere that temperature hikes up to a few million degrees it's a middle

age star, so halfway through its life at about four and a half billion years old. But it is fairly typical in some senses. So what it's made of, its rotation rate, but it's not typical in other ways. So for example, in how active our sun is, and maybe that's something that we can talk about later on. So our sun is an active star's something that we can talk about later on so our sun is an active star it has these explosions and eruptions in its atmosphere but what we've been seeing in other stars is that other stars can be much much more active than our sun but for us it has a nice activity level that means that we can sort of exist in its neighborhood without too much trouble tim i was i wanted to ask you that you, there was an incredible piece of work once

at the Tate Modern which was this kind of projection of the sun coming up and what the artists had hoped was that it would give a sense that for more primitive humans, that sense of almost worship of the sun and when we know the remarkable importance it has, do you feel as someone who's often spoken out about different mystical things, should we be worshipping the sun more i think it seems like a perfectly reasonable thing to worship if you want to i think we we probably lack a bit of ritual in our lives so if you're going to ritualistically dig on something i think the societies who had sort of uh spiritualities

attached to nature and honouring nature, certainly did a lot better than we're doing at looking after nature. So, yeah, I reckon you can worship the sun, although you've got to be careful. Aussies worship the sun and they've got a lot of skin cancer. Depends how you do it. Do it in clothes. Steve, I didn't want to let your intro go without commenting on it

because you made this link, an unusual link, between saying you'd spent your life studying snails and the sun. So I think that at least a brief explanation of what you meant. I know what you meant by it. You've spent your life studying snails and the sun. What's the connection? Well, the connection is I'm what's called a thermal ecologist, thermal geneticist, and one tends to forget

how overwhelmingly powerful the sun actually is. I mean, the analogy I always use in my book, I mention my book, I manage to mention my book, here comes the sun. If you were to take a 300-kilometre square in the Sahara and cover it completely with solar panels, the solar energy that would land on those solar panels would power the entire world forever at no cost, the entire human world forever at no cost. So that although the sun's a long way away and we only take a

minute fraction of its output, from our point of view there's an awful lot of it. But from a snail's point of view, there's even more, because a snail is what shouldn't be called a cold-blooded animal, but it doesn't keep itself warm in the way that we do. So it's constantly standing on the edge of a thermal cliff. It has to move in and out of the sun to stay at the right body temperature. If it gets too hot, it dies. If it gets too cold, it too cold it starves so it's a very pernickety relationship with the sun and the thing which got me involved in that a long time ago 50 years ago really

the early days in the pre-history of genetics, even in the pre-history of physics of course because it was before Brian Cox was invented I wasn't invented Steve we're trying to Ryan Cox was invented, was... I wasn't invented. I thought you... Steve, we're trying to keep this quiet

about the fact he was invented. He still thinks he's a real boy, OK? It's very important that we don't change that. I thought physicists didn't get involved in sex. Certainly two of the physicists I know. Now, I'm sorry, Steve, I'm very disappointed with you as a scientist. Only two physicists as reference points. That is

anecdotal evidence there, I'm afraid. I'm a geneticist, and I start my introductory lectures in genetics by standing up there and saying I'm a geneticist, and my job is to make sex boring and after 24 lectures they know exactly what I mean. Back to the snails we haven't finished the snail thing. I'll finish the snails because there is a point to them. People tend to forget

that genetics is a new science it didn't really get going until about the year 2000 and when I started studying it there was nothing you could look at in nature which was variable, okay? And the snails vary in their patterns, in their color, whether they're light or dark or yellow or pink or stripy or not stripy. And that, of course, and a physicist would probably understand this if I do it slowly, dark objects heat up more in the sun, okay? And so the question was, does the sun alter the genetic evolution of these snails? And the short answer is yes, and it's taken me 40 years to get to that yes.

I just want to slightly argue the statement, there is a point to snails. Not that I think snails are any more pointless than anything, I just don't think there's a point to anything. So, I mean, it's a general criticism. That's true. That's true. You tend to forget, you know, snails saved the human race,

at least marine snails did, because there was a moment in ancient, very ancient history, when the human population size went down to several hundred. There was a huge drought in Africa. And we moved from the Rift Valley to the coasts of Africa, the southern coasts of Africa, and lived off oysters for about 1,000 years. And if you go down there now, and I've been down there and seen them,

there are huge piles of oyster shells. And oysters are, of course, mollusks, snails. So, in fact, we owe our very existence to snails, so they're not pointless. So there we are, Tim, you see. We are covering a lot of ground here today and so little a bit about the sun. The teleological nature of the snail was not expected within 10 minutes. Steve, I wanted to go way back to the origin of life on Earth and its interaction with the sun.

Because, of course, the most common theory now is life began in the very deep oceans, so well away from the sun. So when do we see life beginning to interact with the sun if we take it as most likely that life began in the deep oceans? Well, I think almost certainly almost immediately. I mean, the problem about the origin of life is it's not a question about biology. It's a question about physics.

How do you get this incredibly improbable reaction going? And there are various theories. They seem to change more quickly than life does. The big theory, which I always like because of its name, it was called the black smoker theory. It was called the black smoker theory, and that was the origin of life, because a black smoker, as you know, is an ocean vent which pumps out lots and lots of heat and black matter and has tons and tons of bacteria hanging around it. Then it moved around to a white smoker theory, which isn't quite as hot,

but once it got away from the bottom of the sea, these vents, once it got into the ocean, it had to get into the sun because life needs energy to stay there. Life is an improbable chemical reaction which needs to be constantly fed with external energy. There's a physicist you may have heard of called Schrödinger who wrote a book called What Is Life? And it's an incredibly clever idea he had.

The point about life, the only point about life, is that it's got an inside and an outside. And what life does is to pump in external energy to maintain its own extremely unlikely existence. And without that energy, you wouldn't have life. And so from the very beginning of life, once we got away from the hot ocean floor, we had to go to the sea surface and get, lie in the sun, and we've to go to the sea surface and get lie in the sun and we've been lying in the sun ever since. Lucy we're talking about the the origin of life events that happened you know three and a half four billion years ago even the sun was a very different star then

wasn't it you mentioned that it's very stable but in the early days it's significantly different. Yeah so our sun is middle age now and it's in what we call the main sequence so it's significantly different yeah so our sun is middle age now and it's in what we call the main sequence so it's it is very stable it's not it's not changing rapidly it's you know it's not getting bigger it's not getting smaller but in its in its early phase it was an active star so and when stars are young they're quite active and they have strong winds blowing away from them but now our star has settled down and and also you know when steve's talking and talking about sunlight i'm thinking about the wavelengths of sunlight you know what what is sunlight we know of course that it's visible light that comes through our atmosphere but there's a whole range of other

wavelengths of light that the sun emits and the sun is an amazing emitter and it sends out everything from long wavelength radio all the way through the amazing emitter and it sends out everything from long wavelength radio all the way through the visible infrared and then up into very short wavelength energetic parts of the spectrum so what's what's fascinating to me is that you know how humans have evolved given the light that not necessarily is the light that reaches the top of the earth's atmosphere but the light that comes through the atmosphere, because our atmosphere protects us from the most dangerous forms of sunlight, x-rays and much of the old ultraviolet light. But it's the visible light that makes it through. And so it's fascinating to me

that, you know, we've developed in a way that we can utilise that light. So plants and photosynthesis and the eye, the eye, I mean, I'm not a biologist, as you know, but I'm fascinated by the fact that the eye detects visible light. And as an astronomer, I think about the fact that when you want to see something, when we look into the universe, we build our telescopes, you know, we want to see detail. And the size you build your telescope depends on the wavelength of light that you're using. So our eye is picking up visible light of, I don't know, around 700 billionths of a meter in wavelength. So we can get away with quite a small eye to see a lot of detail. If our atmosphere let through lots of radio wavelengths and our eye was picking up radio wavelengths, which are much longer, you'd need an enormous eye of around something like 3,000 metres across

to get the same kind of spatial resolution that we get with visible light. So there's just something so clever about the way we've evolved, given the star we have on our doorstep and given the light that that star gives to us that we receive on the surface of the Earth look let me let me break in there you can't use a word for like clever for the way we evolve because that suggests that suggests some kind of planning and evolution and natural selection is just a series of successful mistakes it's an error piled upon error and of course if you look at the eyes you will know know, any camera designer who designed a camera in which the light goes through the back of the film

before it gets to the light-sensitive stuff, which is what the eye does, would lose its job immediately. So the beauty of the eye to me and to biologists in general is what a mess it is. And that's what frightens me about physics. It isn't a mess. I like things to be a mess, and the eye is a classic example of it well that is i mean that one of the things that as you know you've dealt with this an enormous number of times uh steve where sometimes

a creationist or intelligent design proponent will say but how did the eye evolve and as you said just there it's a very messy process isn't't it, in terms of development of light-sensitive cells and beyond? Yes, certainly. You know, it's almost impossible to imagine the eye evolving. But the crucial point is almost, you know, every one of us is an almost impossible thing. Some of us on this panel, I have to say, appear to be more impossible than others.

But... Lame names. But that's what evolution does. It doesn't plan ahead. It doesn't. It's not clever. It just fiddles along from one generation to the next. And it comes up with beautiful objects like snails

and horrible objects like human beings as a result. Can you give us the quick review of the snail's eye? I've just got to ask you, because you're one of the leading experts on snails, and it seems remiss of me not to use that. Snail's eyes, actually, are a classic of evolution. You can see every step in the evolution of the eye if you look at different species of different kinds of sea snail

more than anything else. The squid eye is uncannily like our eyes. In fact, it works better than our eyes. So we can see that. But the joy of snails is, there are so much joy of snails, I even eat them now and again. But as I said before, they live

on a thermal cliff and they live on the ground surface most of the time. And the dangerous place for a creature to be on a sunny day is on the surface of the ground because there's a layer of superheated air on the ground surface and they have to climb to get out of it. But the interesting thing is if you go to the Mediterranean, you go to Perth around the coast of Australia, you'll see

millions of these little white snails climbing up on the vegetation in the summer. And they're doing that to escape the heat of the ground. They're a pest in Australia, actually. It's called theba. It's a European snail. But it's fascinating because that was picked up by the early Christians because they thought that snails were resurrected because they climb up a stick in the beginning of summer around the Mediterranean, and they appear to be dead. Then it rains in the autumn, and they come alive again. And if you go to Lambeth Palace in London, there's a thing called the resurrection window,

and it's a very beautiful, well, it should be medieval, but it was blown up in the war. It's a copy of it. But the resurrection window has a picture of Jesus being resurrected and going off to heaven. And there are two snails there. And nobody ever understood why the snails were there. But the snails are there because they're resurrected every autumn as it rains, and they can come down to the ground surface because the sun isn't there. And just to finish the story, that's why we stand up, because when primates came down from the trees onto the ground surface, if they went on all fours, first of all, they'd have much more skin facing the sun,

they'd heat up more, and also they'd be in the superheated layer. So slowly they evolved to stand upright. That meant we could be walk, which is a series of successful falls, one fall after another, which we stop, which turned us into fantastic hunters, which made us what we are. So that's what the sun did. It made us indeed everything that we are. made us what we are. So that's what the sun did. It made us, indeed, everything that we are. I have to throw this to Tim.

Tim, because Jesus, resurrection, snails. Discuss. Yeah, I mean, yeah. I mean, it's really exciting. I want to start a new religion. I think you did write a song, didn't you, called Jesus, resurrection, snails? Honestly, it feels like it might have been a band name I had once. But I like the idea of worshipping snails. That sounds much smarter to me than worshipping some other dude. Snails are pretty cool. Snails and Whales, which, by the way, is my favourite Julia Donaldson book. The Snail and the Whale. It's absolutely beautiful and very profound.

Unfortunately, there's not a book called The Joy of Snails, which would have been a very interesting sequel to a 1970s popular top-shelf manual. Well, Alex Comfort, strangely, I once corresponded with Alex Comfort, who wrote The Joy of Sex. And, in fact, I got what was his job at University College London now. And I wrote to him because I was working as a PhD student on the biochemistry of snail shell pigments. And he'd PhD student on the biochemistry of snail shell pigments

and he'd written stuff on the biochemistry of snail shell pigments so we corresponded back and forth but this was before he wrote The Joy of Sex so I didn't realise the incredible honour which I'd got. I've still got the postcards he sent me about snail shells and maybe they'll be worth something someday. Tim, it feels like it's time for a song! Snails and Jesus and resurrection Tim, it feels like it's time for a song.

If today's show, by the way, Tim, does not lead to your first ever prog album, I am going to be very disappointed. There's a big narrative coming on in this one. Lucy, you alluded to the stability of the sun. We had this climate that's been stable enough for four billion years or so to have an unbroken chain of life stretching all the way back. So if we look out beyond our solar system, so the 200, 400 billion stars in the Milky Way galaxy, can you just give us an overview of the different types of stars,

but in particular with reference to stars that you think may be stable enough to support ecosystems on the planets around them? Yeah, I mean, that's a really good question. And what I love is that in recent years, we've had some fantastic new results coming through with missions like the Kepler mission whose main aim was to study planets transiting in front of stars so when it comes to so we're talking about the light coming from our sun and one of the interesting things is in addition to the fact that you've got all these different wavelengths coming and some of it makes its way through our atmosphere and some of it doesn't is that actually the amount of light given off by the sun varies very, very slightly over time,

over something that we call the solar cycle, which is an activity cycle that lasts about 11 years. And our sun is active and the activity follows this 11 year cycle. But when we looked at other sun-like stars, we saw that they were way more active, producing explosions that were thousands of times more energetic than the explosions we see in the atmosphere of our sun. And so therefore we could conclude that the amount of high-energy ionising dangerous radiation would likewise be much more significant

in the atmosphere of these other stars. So I think there is something in our sun that even though it's kind of a typical star, we may be catching it in a phase in its life where it's just not not too variable and not too active and that could be important for us you know tim i want to ask you a serious question actually which is that i i find when we talk about life on earth and particularly that unbroken chain that's led ultimately to civilization and humanity um the more we learn, the more precarious it seems. And I think you can make a strong

argument, I'll ask Steve afterwards, but you can make a strong argument. There may be one planet on average per galaxy where we have an intelligent civilization. So do you feel that way? The more you learn about science, it's more of a general question, should we learn more about science as a civilization in order to value ourselves more because that seems to me the way that we're led i was just thinking about that what what are the odds that we're the only intelligent life in the universe right so when i was young i didn't know much about anything as opposed to now when i know so much. When I was young and I just went, well, I didn't even know, I didn't even know there was anything really past the solar system.

I didn't really know what stars were or whatever and I thought there's the earth and humans. I had a sort of, you know, earth-centric view of the universe and then as I learnt more and I really got my head around a billion trillion stars or whatever the number was back when I first sort of conceived of it, I thought, well, there must be infinite life because that's the nature of infinity. Even the slightest chance of a thing must repeat infinitely. And then when I, you know, now we talk about a billion trillion stars

and that's a big number like 10 to the 24 or whatever, right? You start thinking, well, what are the odds out of a billion yellow dwarfs, how many are as consistent as ours? And that number might be two or six. But let's call it one. Let's say one in a billion yellow dwarfs are as stable as ours, right? And then let's say for every stable yellow dwarf, life spontaneously erupted one in a billion times, right?

So that's a billion, billion. And suddenly when you look at the odds of all these events and then surviving not going snowball, surviving wars, surviving that bottleneck of sapiens in Africa because of mollusks. I mean, when you multiply a tiny chance things by tiny chance things, 10 to the 24 suddenly doesn't seem enough. I have just recently started thinking, hold on, I'm not sure it is mathematically impossible that we are the most

intelligent life forms ever to exist and if that's the case we should stop yelling at each other on twitter pronto you were i mean tim that's an interesting thing where you're talking about knowledge there i remember the first time talking to lucy when talking about the work that she did and when lucy when you were talking to me about the first time of actually observing the activity of the sun, I think a solar telescope where you're suddenly seeing something which is whatever you have imagined through equations or through academic books. That sensation of seeing something which you've been unable to imagine before. I mean, that's remarkable, isn't it? It is. It is one of those life-changing moments. And the thing that I think is that the sun is so familiar to all of us.

You know, it's there every day consistently. It rises in the morning, it sets in the evening. And so we know it, but yet we don't know it because it's so dazzlingly bright, we can't look at it. And so I had this, this yeah sort of transformative moment when I was um it was actually in Crimea and I was um visiting an observatory there and uh this lady who ran the solar telescope said oh I'll come to my telescope and we'll have a look at the sun through a specialist filter and I mean I just couldn't believe it this you know bright dazzling

thing in in the sky that had been there all the time suddenly was revealed as this structured dynamic beautiful object like the beauty in it i never expected and when you see the structures and that's why i'm so thrilled now that we have you know public access to all the data that we're collecting so everybody can see that everybody can see that the atmosphere of the sun is this amazingly structured gas with these beautiful loops and you know sinuous structures and and that when they erupt you know it's it's it's all the superlatives it's you know the most energetic most powerful biggest fastest all these things but the beauty in it is something that i think we should um that we should recognize in a blood too so much how I felt when I

first went jogging with Brian the fastest the most energetic all these years he'd been there but I didn't realize how beautiful and energetic he was but then then then we had a then we had a boxing match didn't we then we actually then we went boxing together. And then he saw my beauty. Yes, the sheer power. Which is even harder to see. You have to look for a long time. And then that evening... Then the seagulls turned up. My coronal mass ejection in the evening.

I've worked out two edit points from what you've said today, Tim, so far for the Radio 4 version. But Steve, the counter argument, I suppose. So we've talked about this potential, the rarity of our system, the system of planet and star. But I suppose the counter argument is that life is ingenious once it starts. And as you've said, it responds to challenges. That's what evolution essentially is. So I wondered what your view of the balance between these arguments,

the idea that we're in some kind of Goldilocks position that may be on average one per galaxy or even one per several galaxies, as Tim said, or that evolution is so, well, life is so robust in meeting the challenges through evolution that maybe we're not so rare. The origin of life is a very, very improbable event. And it's often pointed out that almost by magic we're in the Goldilocks zone, you know. But of course, we would say that because we evolved to live on this planet. It is conceivable, I suppose, on distant planets that life has evolved in a totally different way. Maybe it's a gas, okay? Remember, life used to be a gas long ago. Maybe it's a gas, maybe it's a crystal,

but it's copying itself and it's maybe changing to adapt to circumstances, but we wouldn't recognise it as life. And no doubt that gas or crystal is probably thinking to itself in its smug way, as we do, oh, isn't it marvellous, we live in just the kind of place where life can evolve. So my own perception, I'm very far from an expert on it,

I would imagine that life of the kind our kind of life what we would recognise as life I would say we're probably a one-off but the probably definitely comes into that sentence Lucy do you think we're what's your take?

I just ebb and flow over this before I knew much at all about astrophysics I think oh yeah it's totally a numbers game um and I'd come at it from these large numbers and think oh yeah there's billions of stars and and what we know now is that there are even more planets in the universe than there are stars in the universe because of all these exoplanet studies and so that made me think oh oh, it's a numbers game. You know, I know nothing about biology.

I haven't studied that since I was about 14 years old. So I think, of course, of course, there will be other life out there. But now I think the nuances of stars and their activity and the nuances of the planets that we're finding with the, you know, varying atmospheres varying compositions varying distances from their star to be honest i don't know anymore i feel that i completely and i i think when you stack those numbers and numbers and numbers just to talk about life being having long enough to evolve to multicellular complexity and then you hit the emergence of consciousness, as I say,

a billion trillion suddenly doesn't seem necessarily enough star systems. Yeah. You know, because I don't know, the emergence of consciousness seems to me freakier than the emergence of life. Well, I mean, how do you compare them? It's like the Beatles and Oasis. You can compare them. It's not that hard to compare.

Yeah, that's not a problem. The other perspective I look from is the kind of, you know, humans putting themselves on a pedestal or knocking us off the pedestal. And that kind of ebbs and flows with this as well. So I'm kind of drawn to the numbers that lead to us not being the only intelligent life that emerged because i'm sort of wanting us not not to be special in some way because that you know that affects our own psychology yeah it would be such

a pity if this is as special as it gets that's not something I want to be true. If the greatest intelligence in the universe sat in its Ugg boots looking at Twitter all day, it's so depressing. Tell me that's not true. I mean, I wanted to move this on because I know we're getting a little bit close to the end of the show, but one of the reasons that we decided to do this

on in this particular series was we were thinking during the lockdown, certainly in the UK certainly uh in the uk one of the the fortunate things was that it had been very good weather that i think that when you are actually you're in an enclosed space to have that sense of light to have that sense of sunshine i think has had some benefit when people have been facing a lot of anxiety and difficulty so we wanted to kind of talk about and i wanted to talk to you first of all, Tim, about this, which is that sense of sunlight when you get a cloudless day. Sorry, that's I think actually a line again from one of your songs. But when you do get a cloudless day,

when you get the sunshine, that does seem to enhance humanity. It doesn't merely seem to be some kind of hippie idea that, oh yeah, the sun's right, that it really does change you psychologically. And I wondered about for you personally, creatively, yeah, the sun's... that it really does change you psychologically. And I wondered about for you personally, creatively, whether you find that does have an effect on you. I don't know. It depends what you're aiming for because a sunshiny day might make you write a sunshiny song

and that's not necessarily what you want. But I do... I'm absolutely sure, or at least it seems obvious to me, that the physics, the biology of us that requires sunlight, exactly what Steve was talking about, that really our relationship with the sun is the true origin of life and is consistent through all living things.

I mean, I wrote a whole musical that uses the rising and the setting of the sun and, you know, based on Groundhog Day, that talks about a day as a life and that the sun is the beginning, you know, the rising of the sun has always been birth. That's why East is called East because it's where East from egg, isn't it? Oostra, whatever, you know, like the sun coming up has always been birth and the sun going down has always been death i mean we have a profound metaphorical physical intuitive relationship with the sun and it is definitely when i lived in the uk for eight years it is

you know you talk about sort of geo-psychology or whatever the culture of the UK is affected without doubt in my mind by this depression that settles over you all when you're just a month after Christmas and you think oh god are we still is the sun still going down at four o'clock you know and that affects your culture in good ways it makes you more creative and maybe write more books and study more snails or whatever but also in bad ways in which you do definitely have a sort of society-wide depression which sits on you for a month or two but then the spring comes and you have this joy which i haven't seen in australia because we Australia because we don't have the – it is not withheld from us, so we don't have the ejaculation, you know. If that's all there is.

Yeah, I mean, it's interesting that George Harrison, when he wrote Here Comes the Sun, that was after the winter of 68, 69, which was the coldest and grisliest winter of the century up to then. And he says, you know, the sun came out, and he picked up a guitar and wrote, Here comes the sun. My God, I wish I could do that. But there's an interesting, you know, what you're saying is correct.

The sun does, of course, cheer you up. And as I mentioned at the beginning, I spent ten years living in Edinburgh. And if you think a London winter is grim, try a Scottish winter. But it cheers you up for reasons we understand now. Because if you go out on a beautiful, sunny day, let's say in Edinburgh, which is an extraordinarily beautiful city, and the sun's out, you think to yourself,

oh, God, this is such a delightful place, I'll stay here. But then the next sunny day is, of course, three months later. But we now know that what the sun actually does, if you go into the sun, it actually generates mood hormones in your skin. Serotonin is one of them. And it changes your mood physically through these hormones. And there's a very bizarre paper to deal with sunbeds, which I was reading the other week, where people lie on sunbeds. And sunbeds are really big in the USA, much more so than they are in Britain. And I'm sure you don't need them in Australia.

And some people, women more than men, really become dependent on these sunbeds. Addicted, yeah. Yeah, they become addicted. And the people who did this work were concerned about the health effects because they're powerful, penetrating, ultraviolet light in these American sunbeds. So they did an experiment where they sent to, let's say, 100 sunbed users, okay, we'll pay for you to go on these our sunbeds for a week. And we want you to describe your feelings about our sunbeds, whether they're working or not, whether they're doing anything for you. And the cunning

trick was to doctor half the sunbeds so they only made bright, visible light and no ultraviolet. So people lay on the sunbeds, and within two minutes, the people on the experimental sunbeds said, hang on a minute, there's something wrong with this sunbed. It's not doing anything for me. And you can go further, and you can use drugs that block these mood hormones, opioid drugs that block the hormones and if you put them on a proper sunbed with their hormones with the drugs that block these joy

hormones they don't enjoy the sunbed so the sun literally as well as metaphorically makes your day i'm gonna make my moody teenager who won't go outside watch this she'll make me buy her a bloody sunbed teenager who won't go outside watch this. She'll make me buy her a bloody sundae. But it's a remarkable fact that British teenagers now go outside for one hour a day less than they did just 10 years ago. And lots of British teenagers are deficient in vitamin D as a result. And that, of course, is the mobile phone culture. You don't need to go out anymore. And people, you know, people

in the medical business are very concerned about it. But I don't know what we do. Move to Australia, I would say. Well, we say, I just wanted to, the last line of your book, which I think is very beautiful, and so I wrote it down, and it sums up what we've been talking about. You say, given the role of the sun's rays in

health, in happiness, in memory, in food, in water, in the shape of the world around us, and in our very existence, its behaviour in the next few decades should become a topic of almost as much interest to men and women as it has long been to snails. A wonderful way to end. Right. So we also asked the audience a question. And today's question was, in the film Sunshine, scientific advisor Brian Cox, the dying sun is restarted by a nuclear bomb. Have you got any better ideas?

So these are the answers that we had. My favourite, to tee you up, Robin, Roly Horwood said, get Brian Blessed to shout at it. For heaven's sake, keep siding, you bastard! Keep bloody siding! Sound people I really pulled back from my mic at that point.

It's a weird thing because I haven't been touring and because I've generally been in my attic room, I have not done any impersonations of Brian Blessed for a long time and I forgot how happy it makes me feel. Anyone who is, I promise you Tim, if you are looking for a way

sometimes to think I'm feeling a bit bleak, you go Oh, don't be so bloody miserable! It really really picks you up, I promise. I'll just ring you and get you to do it. You ring any time you want, day or night, I'm ready. The rest of my family might be surprised and my neighbours, but hey, that's the cost of it sometimes.

This is nice. Coprolite 9000, now there's a name, says, have an enormous dung beetle kicking about the sky a bit. I love that. Throw in a strawberry? Hit it, Tyler says, hit it with focus light from a nearby star using a giant magnifying glass from orbit so that we can also use that enormous eye

that's eventually going to evolve that Lucy was talking about before. Lucy, would that work? Well, I mean, you need temperature, but you need density too to make these interactions probable. So maybe blast it. And but you need density too to make these interactions probable. So maybe blast it. And also you need fuel. So it depends why the sun stopped shining.

If there's not enough hydrogen, shove some hydrogen in, heat it up, compress it. That's basically what a star does. I've never heard the restarting of a star described in such a beautiful, one is fun, Delia Smith way at the same time as well. Just slap a bit of hydrogen in, off you go. There we go. Take the sun straight out the oven, you're done.

Lovely job, Eddie. My favourite was James Arnold put 50p in the meter. Next week, we actually still have no idea what our show will be about. So what we thought is using Brian Cox's knowledge of probability and inputting the information that we've already done shows on the end of the universe, black hole, space, archaeology and exploration and the sun. What does your android brain predict, Brian?

Physics. Right. I want to do chimpanzees, so we'll find out which equation is correct next week. We could do 2001 then. So compromise. Yes, a little bit both physics and chimps well i'll tell you what i'll ask jane goodall and i'll see which one she wants i did

mention we got jane goodall on next week did i not oh okay anyway so uh i think she'll probably go with the chimpanzees anyway thanks very much everyone for listening and uh as we said next week uh jane goodall bye In the infinite monkey cage Without your trousers In the infinite monkey cage Turned out nice again Hi, I'm Catherine Bellhorst And I'm Sarah Keyworth

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