The Infinite Monkey Cage - Southern Skies

Episode Date: February 18, 2023

Brian Cox and Robin Ince start a new series from Sydney, Australia. They are joined by astrophysicists Kirsten Banks and Devika Kamath and comedian Ross Noble as they discuss how different the night sky looks from the southern hemisphere. They hear stories of how different cultures have always used constellations in the sky to help navigate life down here, on planet Earth. They find out how just one point of light can tell you exactly what a star is made of and why this can be the key to understanding the future of our galaxy. Producer: Caroline Steel Executive Producer: Alexandra Feachem

Hello, I'm Robin Ince. And I'm Brian Cox, and we're back for a brand new series. New episodes will be released weekly, but if you're in the UK and can't wait, you can hear it all. Right now, before anywhere else. First, on BBC Sounds. It's a wonderful platform. So good. I'm Robin Ince. And I'm Brian Cox, and this is a new series of The Infinite Monkey Cage.

And today we are in Australia again. Of course we're in Australia because, as many Australians will know, when you've kind of got a sitcom in Britain that eventually is starting to fall apart and reach the end of its life, it comes to Australia. So, Are You Being Served, Tony Hancock, Love Thy Neighbour, all of them eventually found themselves here, and so do we. I wouldn't say we're a sitcom. There's no place for comedy in science.

That's why we work well together, actually. Meow! It turns out, Schrodinger, the cat was alive. That was my first and only ad lib of the evening. Which is weird, because when I hear you talking about physics, I think you're making it all up. One of the great joys of the southern skies is the view afforded of our galaxy, the Milky Way. The southern hemisphere points directly towards the galactic centre

and the rich star clouds of Sagittarius, the constellation of the Archer. And, of course, that's one of the reasons that we've picked that particular one, the constellation of the Archer, because anyone here who is a regular radio 4 listener knows that anything that involves the everyday story of country folk even if it is from an astronomical point of view wins over an audience and this by the way was a joke that brian suggested that we put in and he said it's really going to work and that shows both of us are doing heavy lifting, but very much in different genres here. Does anyone have a clue what the archers is?

Yes. I see. So it just wasn't funny then. Yeah. You all got all the context and all the background. I think it was because you said archer singly. Yeah, yeah, yeah. I think that's one of the problems.

It was the singular rather than the archers, which suggests the everyday story of country folk. So I think you'll find it was your delivery initially that destroyed that. But it's not called... It's the archer, isn't it? Yeah, I know. That's the problem.

You see, this is the issue with doing jokes and mixing them with science, is because science has to be accurate, very often that means... Whereas comedy involves misunderstandings, right? Whereas you go, a misunderstanding, I cannot have that. That is not the Schwarzschild radius at all.

But it is if we're going to do the black hole joke. Well, we can't do the joke then. If you want to talk about science, what you've employed is the Shuler principle. And that's a very specific Archer's joke. There was a character called Shuler in it for many years. Well, I'll tell you what, we still haven't got a laugh, but you get a lot of respect.

You get a lot of respect for being niche. We're talking about the archers in Sydney for an Australian audience. Magnificent. We'll change the joke. So if you say, of course, it's wonderful, the rich star fields of the Sullivans, and then I'll say something about the TV soap opera

The Sullivans that ended in 1982. The block universe still runs. The southern hemisphere points directly towards the galactic centre and the rich star fields of The Sullivans. There we go. You see, you got a laugh. We didn't have to do anything else with it. That was like a Beckett play. Brilliant. Anyway,

now you do your next bit, which is you sounding a bit like Carl Sagan. The deeds of heroes and gods in the skies. Yep, go on. The night sky is a bit like Carl Sagan. The deeds of heroes and gods in the skies. Yep, go on. The night sky is a place of beauty and legend. The stars have always told us stories of origins and endings. And the deeds of heroes and gods. But what stories do the stars tell us today?

What secrets do they reveal when we gaze at them, not with human eyes, but with the telescopes and instruments of the 21st century? Today, we are at the Powerhouse Museum in Sydney and with us to discuss the magic of the southern sky and its stories past, present and future, we are joined by two astrophysicists and the 11th greatest stand-up in the world. And they are...

I'm Kirsten Banks, I'm an astrophysicist and science communicator and the weirdest thing I've seen in the night sky is while working at Sydney Observatory as a tour guide, I saw this really bright light thinking maybe it was Venus, but it was in the wrong spot. So then my undergrad brain went, am I seeing a star exploding? No, it was just a plane. I'm the Vika and I'm a stellar astrophysicist and a senior lecturer at Macquarie University. Something in the night sky that really touched my heart was the transit of Venus in 2004. Now, the transit of Venus is very special because it is an event that, you know, back

in the 1770s, when Captain James Cook came looking for it in the Pacific Ocean, he didn't really see the transit as well. But he did land up mapping or rather discovering Australia. So the transit of Venus helped him sort of spot Australia. And in my case, I was a student back in India in 2004. I saw the transit of Venus and I landed up in Australia for my PhD. I'm Ross Noble. I'm a stand-up comedian. And the weirdest thing I've ever seen in the night sky was a strange pulsating orb. I was in Wales. I won't tell you what I was doing but I was on a

Welsh mountain in the dark. I was having a wee. I'll be honest I was having a wee and behind me a strange red orb started pulsating. I looked up thinking it was a UFO, right? It was the red light on top of a wind turbine, and every time the blades went round, it went on and off. Not a UFO at all. I presumed it was the police. We've told you before.

Yes, you're right. Stop urinating on that slide. But it's also completely inaccurate because it's not in the sky then, is it? It's on top of a wind turbine, so it doesn't count. It was bloody high, though. Yeah. Hang on.

Sorry, first question from a layman's point of view. Where does the sky begin? Oh, I've gotten this question on TikTok many, many times. On TikTok? Yes. Sorry, it wasn't accompanied with a dance. That's the secret. You've got to dance while you're doing your science.

Where does the sky... Because I've got a big ladder. That's a good start. I've got a big ladder. When Jimi Hendrix said, excuse me, I'll kiss the sky, is it possible to do that with a ladder? Well, see, I would argue that the sky starts

where Rayleigh scattering happens, where we get the blueness of the sky. And that happens in some kilometres above the ground. How many kilometres? Some. Some? Yes. Right.

Where the blueness starts. I'm from the north-east of England. I didn't see blue sky until I came to Australia. Technically, that means there's no sky. How about anything above the horizon? That could be sky. That's very far away, though. Yeah.

You see how difficult it is doing this show. I was hoping we were going to deal with the death of stars, but I don't think we're really going to get beyond the end of the pier, are we? Anyway, this is our panel. Also, by the way, can I just say, Davika, I was impressed when you were talking about Captain Cook and the transit Venus. The difference between when you came here and he did is you worked out you hadn't discovered it, that there were people here already and you weren't the first.

Very true. Kirsten, we'll start off with you grew up under Australian skies. And I think for a lot of people, they think the sky, wherever you are in the world, is the sky and you'll get roughly the same thing. And then you come to the Southern Hemisphere and you discover that this is a totally different picture. Oh, yes. I believe we have the best view of the night sky here in Australia and other Southern Hemisphere countries, of course.

But that's because, like you said at the start, Brian, that we have the most privileged position where we look directly at the centre of the galaxy. And there is so many stars, but also not stars there as well, where you can see some really interesting patterns within the dusty bands of our Milky Way galaxy. And Davika, many people listening to this will not have seen the majesty of the southern sky. So could you take us through some of the highlights that you see? Sure. So I grew up in the northern hemisphere in the southern parts of India. So I was, you know, very familiar with the northern sky. And then when I came to Australia, the first thing I noticed was everything was upside down. This is down under and everything. Orion, one of all our favorite constellations, was upside down.

And I was like, why is the hunter upside down? And I realized, well, that's Australia. It's just different. But, you know, the southern sky, as Kirsten said, is just spectacularly beautiful, though it confuses you in terms of orientation, because the other thing that you only see in the southern hemisphere is the closest star to our sun, which is Alpha Centauri. You cannot see this in the northern hemisphere. You know, you have our sun, and we're all happily,

you know, enjoying planet Earth for as long as it lasts. But then there's another star, Alpha Centauri. So there's a lot of new objects that you can't see in the southern hemisphere that you can. Now, one that you can see in both hemispheres is Andromeda, which is the closest galactic system. And you can see that in the northern hemisphere, but for three months, which is kind of nowish, you can see it in the southern hemisphere.

So there's a spectacular system. It feels to me like if anyone here has ever been one of those like universal studio tours i would always pick the wrong side of the ride to go on so jaws would always be coming out of the water on the right hand side when i was sat on the left the baits motel would always be on the left hand side if i was on the right and that's kind of what it's like being in the northern hemisphere isn't it we're looking right at the ass end of the galaxy and there's a great view down here, isn't there? I mean, that's the thing, is we see a very different sense

of even the potential of the stars. For Radio 4 listeners, arse end means outer spiral arm. Arse end was a very popular sitcom in the late 1950s. Please welcome Kenneth Horne with Arse End. And a lovely suburb of London as well. It's weird, isn't it? Because you said before about Orion being upside down. And I thought the first time I came here and I saw that,

because that is the one that you notice and you think, thank God he's got a belt on, his trousers will fall down. That's all the Australian beer. That's what it is. And Kirsten, it's interesting you refer to Orion because that's one of the legends. It's Orion the hunter. But you were a jury woman.

And so you grew up with different stories of the stars. So could you take us through some of the stories in the sky? I would actually love to share with you one about Orion, but we call it by a different name. In Wiradjuri, we call it Biami. It's the creator spirit. But what's interesting about this is that it's the exact same stars creating the picture of a man, but to Wiradjuri perspective, it's the same orientation as Orion,

upside down. Which seems weird when you first think about it, like we're on the, you know, the right side of the world, and it should be the right way up on this right side of the world, but it's not, it's upside down. And that links into one of the stories where Bayami is chasing an emu, which we call Dinawan. And as he's chasing Dinawan the emu, he trips over a log and falls flat on his face. Not so great for the creator spirit, but that is reflected in the stars. If you watch Orion or the stars of Orion, the stars of Bayami setting in the western sky, he sets headfirst into the ground, just like falling into the ground like the story it's illustrated in the stars that's really that's interesting that you would build the stories around

an upside down character and you know that's really because like he was chasing the emu whereas in the northern hemisphere we have an emu that chases people with an old man called rod hall i think there are richer stories that's astronomy really it's looking up at the sky with an old man called Rod Hull. I think they're a richer story. That's astronomy, really. It's looking up at the sky and trying to figure out what's out there. So, you know, different cultures looked at it through different times

and they interpreted it the way they saw it. The Emu is the only constellation that is not made solely of stars. That's right. In Wiradjuri, we call it Gagoman. And if you look for the Southern Cross, one of the most iconic constellations in the Southern Hemisphere, in a place with very little light pollution, you're not going to get it here in Sydney, unfortunately. But just below the

Southern Cross, you have this dark triangle shape of dust that we call the Coalsack Nebula in Western astronomy, but it makes the head of Gugurman, the head of the emu. And as you continue along the sky towards the centre massive bulge of our galaxy, you have this thin band that makes a long neck of the emu and then the bulge of the galaxy is the body of the emu. And its position in the night sky indicates to us as Wiradjuri people when is the right time to go looking for emu eggs. So when it's kind of just coming up above the horizon after the sun has gone down, it kind of looks like an emu running along the horizon. So that maps and mirrors down onto the ground

that the Dinawan, the ground emu, are running around looking for a mate. But then later in the year, as the Earth moves further around its path around the sun, that center of our galaxy rises higher and higher into the sky, and then our perspective changes again. Instead of it being a body of an emu anymore, it's now an emu egg in a nest.

And that tells us that now's the right time to go looking for emu eggs. It seems that a lot of First Nation astronomy has been ignored until more recently, and there's a lot more books coming out of this. And it seems that there was a lot of first nation astronomy was kind of dismissed because it was interpreted as being literal as opposed to the fact that's the way we remember by having these vivid tales absolutely much easier than any textbook so the untrained eye people who aren't astronomers you look at the sky and you see points of light and all those points of light basically look the same and so could you take us through

the differences that are up there right how much time do we have for this program because there are many types of stars out there have you got any plans for thursday and as we also know time is an illusion possibly a construct so fantastic yeah so let's start at the very beginning the The sun is a star. It's a pretty ordinary star. It's currently burning hydrogen in its core, turning it into helium. It's a main sequence star. Most of the stars we see in the night sky are in this category of main sequence. But eventually when stars like our sun run out of that nuclear fuel in their cores,

the core itself will shrink because it's no longer being held up by this pressure of nuclear furnace. And it starts to grow bigger and bigger and turn into a red giant. And eventually, depending on what type of star you are, you'll go through a different category or a different journey of life. If you're more massive, you have more mass as a star, you will live fast, die young. massive stars do it well, and you'll turn into, thank you, I'm sometimes funny too. You have these big red giant stars, there are different categories of red giant stars, you have your red giant branch, which is like a branch on this graph that we show in astronomy,

you have your red clumps, which are a clump of red stars in the big graph as well. We're really good at naming things in astronomy. Is that the technical term, a red clump? Yes, literally called a red clump. That is my entire PhD on the red clump stars. Yes. That's what you found in the plug after Ed Sheeran's been around. Come on, Ed. I love it. The speed you drag it down is incredible. That even had a visualisation of something being dragged down as well as you do. Yeah, beautiful. Because Kirsten said, I can be funny too,

you were like, no way! I've got an edge here in gag now. Red clump's the best thing I've ever heard. Oh, yes. So what is a red clump? A red clump star is a type of red giant that is burning helium in its core. So it's gotten rid of all the hydrogen. The core's kind of just hung out just being helium for a little while,

while a shell of hydrogen fusion is happening outside the core, creating more helium that's heavier than hydrogen. So it's falling down into the core until it gets to a point where it's, I believe, about 1.4 times the mass of our sun, and then that helium ignites in what we call a helium flash. Again, we're really good at naming things in astronomy. And then when it's burning helium in its core, that's a red clump star.

I don't feel bad, by the way, just about astronomers naming things. Look at biology. Blobfish. Why do you call it that? It's like a blob. Imagine that. All that evolution, and what do you end up being biology. Blobfish. Why do you call it that? It's like a blob. Imagine that. All that evolution and what do you end up being named? Blobfish. It's not fair, is it? I must say, it's quite accessible, though. It looks like a blob. And it does look quite like a blob as well.

But doesn't the blobfish, when it's in the water, it only blobs when you take it out of the water? Yeah, yeah, yeah. It's very disappointing. Yeah. When it's floating, it's alright. Yeah, it's magisterial. Non-blo, yeah. It's very disappointing. Yeah. Yeah, yeah, yeah. When it's floating, it's all right. Yeah, it's magisterial. Non-blobfish. It's exactly what you don't want.

This is a show about astronomy. Stop talking about this stuff. Okay, let's get back to the record. Like a star's dead, and then the light takes so long. I don't need to explain this to you, but if that was... You can try. No, Ross, I want you to. Go ahead and try.

You amuse me. Kirsten did jokes. You're allowed to, Russ, I want you to. Go ahead and try. You amuse me. Kirsten did jokes. You're allowed to do so. That would be deeply unsettling. If your gran died, but you could still see the light coming off her at the funeral. You go, do you want a sandwich? Ah! You're meant to be dead.

Give it a thousand years, I'll be gone. Brian, can I just say, you've never looked more confused. I'm just trying to work out how to steer it back. I think you've been steering it back all the time. It's absolutely fine. Davika, your research is based on, first of all, measuring the composition of stars.

Could you run through how it is that just from the light, a point of light in the sky, we can understand exactly what that star is made of? So like I said before, stars have a chemical composition. And one of the longstanding research questions we have is, where do the elements in the universe come from? And when I mean elements, if I take this glass of water, it's got hydrogen and oxygen in it. The question is, where is this hydrogen coming from? Where is this oxygen coming from? And like I said, not all stars make the elements at the same time. As Kirsten said, young stars are just making hydrogen into helium.

They're not making carbon and so on. But the question that Brian asks me is, how do we know? So I spend all my day looking at starlight and turning it into rainbows. That's my life, guys. It's beautiful. And the way I do this is I stare at a star and the starlight comes to me and I put it through a prism and that prism breaks up this white light into the colours of the rainbow. That's what it does, right? White light through a prism gets broken down into the colors of the rainbow. But now imagine my star has helium or neon or argon or whatever the chemical element is. When the photon from the core of the star is passing through this element, some of the energy of the light particle is absorbed by that element. So what happens is when I look at my rainbow,

I either see dark lines because some of the light has been absorbed by that particular element. What we can do, and this is measured in laboratories and through atomic physics, we can tell the missing lines to great precision where I know when a line is missing, I know which element it represents. And in some cases, the line's not missing or the light particle is energized. So the light can either be absorbed by the element or it can be energized by the element. And that's going to show up in my spectra

as what I call an absorption line or an emission line. In my beautiful rainbow, it's going to be a bright line or a dark line. It's simple. It's so cool with studying stars like that. Like we're getting information not from the light that they emit, but from the light they don't emit. That's right.

So basically elements have a chemical fingerprint just like you and I. Very, very unique. I've just got this image of you, like people walking past your lab and the doors open, it's just rainbows flying out of the lab. Oh, she's exploded on my little pony again. It's either astronomy or it's the Lucky Charms factory. One or the other. I can't be sure which. It's interesting. When you think of the galaxy,

400 billion stars give or take. Some people say 200 billion. Astronomers don't care about factors of two. Whatever. 400 billion. And we tend to think that that whole galaxy has the potential to be like this part of the galaxy. So could you explain, Kirsten, where we are in the galaxy, so our solar system,

and how the galaxy changes as we move inwards towards the core? Right. So we are kind of in a bit of the outer suburbs of the galaxy. Our galaxy is a big spiral galaxy with maybe two or four spiral arms. We're not too sure on that one, I'm pretty sure. Yeah, a few. A factor of two, you know. Even that's remarkable that we don't know how many spiral arms our galaxy has. Absolutely. There are so many questions that we still have yet to answer. But we're kind of in the outer suburbs. Our galaxy is around 100,000 light years across, and we're about 25,000 to 27,000 light years from the center of our galaxy and that seems to be quite a good place for life to form there's some good stars around here we've

got a pretty good one that's up during the day most of the time no not from olden just in case you're wondering a light year is quite a lot of distance that's like almost 9.25 trillion kilometers i don't know if that's made it any better or worse, but I'm just saying it's quite big, no? Location, location, location. That's what they always say. That's it, that's it. That's the centre of the universe. Oh, God, I've got to get an Uber.

And the nearest star is about four light years away also. About four light years away from us, yes. So while there is a lot of space in space, we've got a lot of space between us and the next star. Sorry, you just sounded like me there. There's a lot of space in space. It's a good line.

Is it wrong? Yeah. No, I'll tell you what. I believed you when you said that, and I would not believe it if you said that. Yeah, sorry. There's a lot of space in space. That's why they call it space.

Space. That's right. call it Spears. Space. That's right. Indeed there is. Still haven't got it. No, I wouldn't trust you. We live in a bit of a spur of one of the arms of our galaxy called the Orion Arm. And as you go further into the galaxy toward the supermassive black hole at the centre of our galaxy, recommend looking at it from a far distance,

you get much older and older stars that are just kind of hanging out in this bulge of the galaxy. As you go through the spiral arms, you tend to have younger stars that are just being born. Our sun's around five billion years old, at a bit of a middle-aged sort of star. And as you go higher and higher as well, we find that there's actually lots of neutron stars and black holes just flung out from different supernovae events. That's a new pit of science that we've come out recently. It's really, really interesting. And some older stars kind of up around the dinner plate of the galaxy, I like to call it. Why are the older stars towards the centre? That is a great question that I'm going to fire to Davika. Davika's going to throw it to Robert.

that I'm going to fire to Davika. Davika's going to throw it to Robert. You just stole my line, Robert. Thank you. The old ones, they all hang around together. Sorry. Are you sure, Ross? I don't want to steal your thunder here. I don't.

Okay. Well, it's actually to do with what we believe is the formation of every galaxy. So typically what happens is when you have a galaxy being formed, there's two models that you can either start from outside going inwards, or you can start because of some sort of turbulence in this massive giant molecular cloud, and then you start inwards going outside. So what we find based on observations of most galaxies is almost every galaxy has a supermassive black hole, almost every galaxy. Because of the way the galaxy is formed, we believe

that it starts off with this supermassive black hole because of the way the cloud collapses, which is this massive cloud of dust and gas. Now when you have a star being bombed, it's also forming because of the gravitational collapse of a cloud, but a baby cloud. If you have a star being bombed, it's also forming because of the gravitational collapse of a cloud, but a baby cloud. If you have a big cloud, then when that collapses, you land up with the formation of a galaxy. This is what we believe at the moment based on observations. And then the configurations of stars start off with being older towards the bulge,

and as you go outwards, you'll end up forming disks, and the much more younger population is in spiral arms. I'd forgotten we were recording a radio show, and I'm just getting very interested in this physics, and I should probably not do it. It's not the first time. We should probably talk amongst yourselves. I've got some technical questions.

Yikes. But we should perhaps explain that the mass of a star is related to its lifetime. When we say mass, we're always comparing it with respect to our sun's mass, okay? But we should perhaps explain that the mass of a star is related to its lifetime. When we say mass, we're always comparing it with respect to our sun's mass, okay? So we assume that the sun is one solar mass. So when I say massive, I mean anything between, say, 10 and 20 solar masses and beyond. You know, Itakarina, for example, is somewhere around 100 solar masses.

So we don't really know what the exact mass is. That's a lot of mass. That is a chunky star. That's a chunky star. That's a technical, again. You've got all these notes. Chunky star, red clump, you're getting the whole lot. Exactly. A chunky star, I believe it's like Kit Kats, isn't it? It's like Kit Kats, you know.

The regular stars were the original two-fingered ones. I'm fully with you. But the more massive a star is, the more exciting his life is, and the more exciting your life is. It's beautiful, but it can be short, and that's exactly what happens, right? So massive stars die pretty young because it consumes its fuel

at a very faster rate. I just like the way you looked straight at Ross and said it's massive, but beautiful and short. She's flirting with Robin. So Kirsten, what are the most elusive elements for the time being? I mean, are there certain elements we really can't seem to understand

where they've come from? We have a pretty good idea of where majority of elements come from. There have a pretty good idea of where a majority of elements come from. There was a really great paper that came out recently showing the evolution of all the elements on the periodic table except one. And I forget what it is. Was it a leucine? That's a tough question.

What I can tell you is that it is a metal, according to astronomers. So it's not hydrogen. So it's not hydrogen or helium. On a periodic table, has it got just a blank square and you open a little door and it's just like... So can I just reiterate that? The advent element, I love that. For the radio listeners, Ross just did an impression of an element,

which was quite impressive. It's a facial expression. Peeking out behind a tiny trap door. See, now that's the element of surprise. impression of an element which was quite impressive it's a facial expression out behind a tiny trap door now that's the element of surprise but it was when when you you can go ross so what is it what is this thing element is very unstable, so we don't see it so much in the spectra of stars and galaxies. I read this paper only recently. This is very embarrassing. I think we've found the problem.

Because it's the most forgettable of elements, I think when the research is being done... Oh, I forgot to check with... It strikes me, for educational purposes in this show, that you mentioned the stability of elements. Just the idea that, well, iron is the most stable element. So if you could take us through how stars make the lighter elements and then beyond iron, it gets more difficult.

Yes, it does, yeah. OK. That's it. Just the panic hop of a PhD student. Please explain this for me. Double magic super-duper element. It's the most Julie Andrews of elements. You love musicals, and yet we've moved straight back to iron. Well, we could stay with that.

I was trying to complete the educational journey that we're all on. Well, actually, it's a very interesting process. So, I mean, you're right, Brian. I mean, most of the time. Anyway, about the elements, I probably stick to the elements. So iron has a really high binding energy of the nucleus. Now, iron-56, which is the number of particles in the nucleus of an iron, is very, very stable.

And if you want to make elements after iron-56, you cannot burn them. So you cannot cook iron like you'd cook pasta. What you have to do is you basically have to add particles onto iron. And we call this neutron capture nucleosynthesis. So you have iron, and then you add neutrons into it. And that's exactly what happens in a supernova explosion. And you have massive amounts of energy, and you have lots of neutrons that come from secondary reactions that happen in the background of the star. So you have lots of neutrons, you have stable ion nuclei, you get the bombardment of, you know, neutrons onto the stable ion nuclei, and you land up making something that's unstable. And then this unstable nuclei,

because it's unstable, it's going to beta decay. Now, beta decay is just a fancy word for saying a neutron converts into a proton or a proton converts into a neutron. That's just what it is. It beta decays into the next element, which happens to be a stable element. So all of the elements outside of iron are made through series of neutron captures and beta decays it's worth emphasizing that what we mean there is gold and silver and platinum so those things we're very familiar with we all own something made of those things yes more than others brian some more than others supernova explosions it is a wonderful thing just just for my records and so what's the future of the sun what what

we're looking at what are the stages before it's over so our sun has another five billion years on the main sequence fusing hydrogen so we're good for now after that it will turn into a red giant star where it will stay like that for maybe about a hundred million years and from our point of view yes yeah this is the fun part yeah yes where the sun starts to expand it will snack on mercury gobble up venus and probably consume the earth as well yep lovely but don't worry before it consumes the earth the earth will be a fiery husk before it even gets to us because of the sun still but as it grows it will continue up the red giant branch for about 100 million years drop down into the red clump phase

where it's burning helium in its core for about 1 million years, maybe 10. A factor of 10, it's fine. Call it fine. Call it fine. Yeah, it's totally fine. Then it will continue up into where the Vika studies does into the asymptotic giant branch. But then after that, staying there for a very short amount of time, a couple million years, it will leave behind a dead core called a white dwarf. And that white dwarf will slowly fade until it becomes a black dwarf. We've never seen that happen before. The universe isn't old enough for us to have seen a white dwarf completely fade into darkness. Well, that's reassuring. But again, five, three years.

You asked that question if you were thinking about your retirement home. Where's going to be the safest place for me? And so when it becomes a white dwarf, sorry, I know this is route one for you, but when it becomes a white dwarf, what does it then do to the rest of the solar system then?

Nothing, because the separations are just too big for it to interact, unless it's in a relationship. Then it might make a supernovae explosion, because it could... Luckily though, we are not in a relationship with another star. But then again, dead husk by then, so...

What does it matter to us? A pink dwarf might turn up, they get together, happy tears, you know? We should put it round up there, I think, Russ. There was just one final question I wanted to ask Kirsten. So I know you're just finishing your PhD. So what is the big question that you would hope to answer? The ultimate question is, why are we here?

And to answer that is answering the question of where are the elements in the galaxy? And to do that, we study the stars. And we can study very specific types of stars that allow us to do that really, really well. That's those red clump stars. But the problem with red clump stars, they look very similar to their red giant branch imposters. We can't use those as effectively to map the galaxy. So what I'm trying to do is to distinguish one from the other using spectra, using spectroscopy. So your why are we here is a kind of geographical question basically. Why are we here? Why are we in this part of a galaxy rather than the bigger philosophical question of why are we here? I tend to digest

that the first one better than the last one. Yeah, I'd say you've got a lot more chance of success to be quite honest. Philosophy is moving slower than we might have hoped. Tameka, what about for you? What is the big question you would like to hope that we can understand within your working life? I think it's really understanding how galaxies evolve with time through the basic building blocks, which are stars. So the big question is really trying to understand the chemical composition of the universe, starting from the basic building blocks, stars. And we don't know a lot of it because of the diversity. It may seem like, well, yeah, we know these stars make carbon,

but there's so many internal complexities. If you take a galaxy and you map the chemical composition of it, it's not going to be a straight line for every element and even the same group of stars some of them will make carbon or some element and some of them will decide no i'm not going to show up today and i'm not going to make this element and the question is why yeah i think it's a wonderful picture that a galaxy this thing as you said a hundred thousand light years, is a big chemistry set. Yes, it is in a way that we don't quite understand. We understand it by and large,

but the intricacies of it is what we don't understand. See, that's the worrying thing, though. If anyone here, if they were a kid, was given a chemistry set, what was the first thing you did? How do I make everything explode? Which means that we might not be the people who should be responsible for the chemistry set. The universe explodes just fine by itself.

Did you want to know the question? I was about to say, Ross. Has your big question changed from what you've heard tonight? No, I'm still the CM. I'm still working on my big question in my research. If you were racing centaurs,

would you just have them racing normally, or would you just have them racing normally? Or would you have miniature jockeys on them with horses' heads? No. Where have you got to so far? To be honest with you, I'm finding it hard to source the centaurs. Yeah. I'm using regular horses with Papiomassi human heads.

So you're hoping this will be an observational science and not just theoretical? Yes, to be honest. When I do it theoretically, the people at the bus stop move away quickly. To be honest, I remember when you had two minotaurs on a unicycle. That was disaster enough, wasn't it? They won't fund my research anymore. The people at the centre.

The centaur centre? The centaur centre. Is that the central centaur centre the central centre the central centre is that the central centre or centre that's right yes what would you no no no Brian don't go further with this

don't well I'm no I'm intrigued now now we've got to if one of the if one of the two possible outcomes you described

were shown to be which one would you hope would turn out to be the correct answer well I would hope I would turn out to be the correct answer? Well, I would hope. I mean, obviously, you've got to decide, do you put a jockey's hat on the human head of the centaur? Yes.

You know? Yes. Technically, they've got a horse's body, but a human head. So that's the first thing. But that's not an observational question. You choose that. Do you choose or do they choose? They've got a human brain, yet a horse's body.

Right. Yeah. To be honest, I was even more excited when you got that cyclops to play darts. The monocular nature of it really does change its ability, doesn't it? Yeah, it's ready to start deflecting him. This is why Brian is the greatest popular scientist, because a lot of people who are very intelligent would go, shut up, Ross. I'm just trying to pin it down. What you have to understand about science is, it's just loose. We don't know all the answers. It's okay, Ross, what you need to say

here is that's beyond the scope of this research. Exactly. And then move on. Well, anyway, we'll be following up on Ross's Centaur Centre research in the next series. We won't. Yes, we will. We'll be putting them in a centrifuge. Yeah. Obviously, if he actually brings us some evidence. It's like when you made up that story about that crocodile on the loose in Newcastle and created that panic.

That's true, by the way. Yeah, yeah, yeah. I made up a story about a crocodile being on the loose in a park in my hometown of Newcastle it is before the internet and I got people to ring up a phone in radio show and say I saw a crocodile in the park and it spread like wildfire I just thought it was a bit of a laugh and the next day four of the national newspapers had the story was featured but the best bit of all is robin at the time was writing on a topical news show and had to write topical jokes about the story in the paper that he knew was bullshit yeah thank you very much to our panel kirsten banks dr vika

kermode and ross noble we asked our audience a question as well. What is the most improbable thing you would like to be discovered deep in the universe? So, the fountain of youth that Brian Cox drinks from. Zanita says, a strawberry seen to a cat, knock, knock. And the cat replying, open the bloody box and find out. Lizzie wants a cocktail bar with hot aliens. Is there one of those in Sydney?

I think that's a cocktail. Can I have two hot aliens? Space cats with laser eyes. You know when your eyesight's not very good and you have the laser put in to fix the eye, would that make the cat's eyes better? If they had lasers coming out of the eyes, would it make the eyes better or worse? You said that so much like an optician.

Better or worse? Can I ask you again, Puss in Boots? Better or worse? Laser cat? Better or worse? Laser cat? Woo! Better or worse? John said dark side of the moon on the dark side of the moon. Took me a while. He wants to find the Pink Floyd album

on the dark side of the moon. I keep meaning to ask you this as well. What happens if you put a werewolf on the moon? The dark side of the moon isn't dark. No, no, no, but he's not talking about that. If it's on the dark side of the moon isn't dark. No, no, no, but he's not talking about that. If it's on the dark side of the moon, it will be perpetually human. If it's on the other side of the moon, it will be a perpetual lycanthrope. But it wouldn't be seeing the moon, it would be seeing the sunlight.

No, no, no, but it doesn't matter. The moon is always going to be full, though, isn't it? But it is, because you're going to be on the moon. Can you explain to him what he's saying? No, no, no. Can I just tell you, just so you know, even though it's night, I'm still able to move around and see things.

No, but I'm just saying that it's not night all the time on the dark side of the moon. No, no, no. It doesn't have to be night to be a werewolf. God, you don't know anything about werewolves. Yet another enormous gap in your knowledge. No, but there's no difference. You said it was,

on the dark side of the moon it'd be one thing and on the light side of the moon it'd be the other thing. But it's not because there's no difference to the werewolf. No, but there's still

the requirement of, it's actually the reflected light. It has to be a full moon. But your perspective wise you're there so you're not getting the full moon. You're only getting

the curvature of the moon. You're not getting the full moon. But it'll be getting because of the moon. You're not getting the full moon. But it'll be getting the curvature. What would the Earth then take in place of the moon? If it was a full Earth, would that be... Only if it was a space werewolf.

Yeah, yeah, yeah. It's always going to get reflected moonlight if the surface is illuminated. That's what I'm thinking. It's standing on the damn thing. No. If it's the Earth, it's going to have its own... If it's the Earth, it makes it kind of wear labradoodle, like that kind of thing, like labrapoodledoodle. It's going to be the pepperoni in the pizza.

That's what it's going to be like. Yeah. I'm just saying, tomorrow, you're going to be in your lab, all rainbows flying around. You're not going to be able to concentrate on your important work. You'll be thinking about the moon. Anyway, so thank you very much to everyone. Next week, our guests include four humans and two spiders.

We have our final show that we're recording in Australia, and we have an orb web spider and a huntsman, both of which you're very keen on, aren't you, Brian? I don't like spiders. Love them. Absolutely love a spider. I'm so looking forward to having the spiders on spider and a huntsman both of which you're very keen on aren't you brian i don't like spiders love them absolutely love a spider i'm so looking forward to having the spiders on because we had an episode once with a crow and you were really annoyed by the crow weren't you because the crow kept walking around and giving you a look that showed that it possibly was more intelligent

than you because it had a little puzzle with this box that had to pull strings and it did it and you couldn't yeah well if the spider does that I'm going to be extremely worried. My top tip on the spiders because I live in the countryside and there's a lot of big ones around and a lot of people they try and catch the spiders and flick them out but when you zoom in on a spider you know how they've got the hair

they're quite hairy creature spiders. Get a bit of hair gel or hairspray doesn't kill them, but it sets them. Right. You just pick them up, put them outside,

rains on them, ooh, I'm off. That's it. There you go. With that, with that, with your rockabilly spiders, thank you very much, everyone. Bye-bye. In the Infinite Monkey Cage. Till now, nice again. Hello, I'm Professor Hannah Fry.

And I'm Dr Adam Rutherford. And together, we're investigating listener-led mysteries. Some people have levitated a frog. Yeah, yeah, I've seen it happen. Has anyone ever levitated a human? In this new series, you'll discover the secret of levitation and what really fuelled the construction of the pyramids.

All the burgers you can eat, lots of beer, and one of the groups called themselves, and I'm not making this up, the drunkards of Menkaura. All this and daredevil experiments too. Now here is the crystal.

Am I allowed to touch it? You certainly are, yeah. Oh, hang on, it's seared off. It's slipped away. The new series of The Curious Cases of Rutherford and Fry. Available now on BBC Sounds. 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. Tax is extra at participating Wendy's until May 5th. Terms and conditions apply.