Mysteries from the Final Frontier

Speaker 1 You're about to listen to a brand new episode of Curious Cases. Shows are going to be released weekly, wherever you get your podcast.

Speaker 1 But if you're in the UK, you can listen to the latest episodes first on BBC Sounds.

Speaker 2 I'm Hannah Fry. And I'm Dara O'Brien.

Speaker 1 And this is Curious Cases. The show where we take your quirkiest questions, your crunchiest conundrums, and then we solve them.

Speaker 3 With the power of science.

Speaker 2 I mean, do we always solve them?

Speaker 3 I mean, the hit rate's pretty low.

Speaker 2 But it is with science.

Speaker 1 It is with science.

Speaker 1 Hello, and welcome to a special edition of Curious Cases, where we're going to do things a little bit differently, because Dara and I are currently in the BBC Radio Theatre at London's Broadcasting House.

Speaker 1 And as you can probably hear, we have an audience.

Speaker 2 And there's another thing we're doing differently as well. There certainly is.

Speaker 2 Because normally in an episode of Curious Cases, we take one question for the entire show.

Speaker 3 Absolutely. We're not doing that tonight.

Speaker 1 We are not doing that tonight. We are going to tackle quite a few of your questions on one single theme, space mysteries.

Speaker 1 And to help us out, we have called on some people who know their way around the universe, the presenters from the BBC TV show, The Sky at Night.

Speaker 2 Yes, the longest-running science program in the world. 68 years old, the Sky at Night is now.
Please, Sky at Night, you can introduce yourselves.

Speaker 3 I'm Maggie Adarin Pocock.

Speaker 4 I'm a space scientist and a science communicator, and I've specialized in building building instrumentation, so machines that go into space and help us understand the universe.

Speaker 4 And these have included the James Webb Space Telescope, the largest space telescope ever built, but also ground-based telescopes like the Gemini Telescope in South America.

Speaker 5 I am George Dransfield. I am an astrophysicist.
I specialize in exoplanets, so planets outside the solar system.

Speaker 5 In particular, I'm interested in gas giants, in particular, ones that are kind of warm and closer to their star than, for example, Jupiter and Saturn are.

Speaker 3 And I'm Chris Lintar. I'm a part-time alien hunter, full-time distractible astronomer.

Speaker 3 Spent most of the summer worrying about the oldest comet we've ever seen, which is paying a sudden visit to our solar system.

Speaker 1 Wow, what amazing guests for this evening.

Speaker 3 Welcome to all of you.

Speaker 3 Do you know how special the sky at night is, Dara?

Speaker 1 They had an asteroid named after them. What was it called, your asteroid?

Speaker 3 It's asteroid 57424 Calem Noctu, which is sort of Latin for the sky at night, but the number was the broadcast date of the first episode.

Speaker 3 And it looks like a dot. I've seen it in a telescope.

Speaker 1 Caleb Nocti, that sounds very fancy, doesn't it? I um, I looked up what curious cases would be if it was in Latin. What is it?

Speaker 1 Um, curiosa casebus, which I think, frankly, sounds like a venereal disease.

Speaker 1 So I'd be maybe they'll name one of those after us die.

Speaker 2 I kind of don't need one because I've got one named after me.

Speaker 3 Have you?

Speaker 3 9901!

Speaker 2 I've called a rank in the room, but yeah, it's

Speaker 2 asterid 4901, and it's just called Obrian, which is Latin for Obrian.

Speaker 3 Also if you know any astronomers almost everyone I know has an asteroid.

Speaker 3 That number is also their pin number. So it's a very useful thing to ask astronomers.

Speaker 1 What does yours look like through a telescope?

Speaker 2 Mine is the binary system.

Speaker 3 Wow, you're just showing this.

Speaker 2 I mean I was kind of forced into it but it is very much my brag.

Speaker 2 It's a really interesting system actually. It's like the one that they use to test whether you could dent an

Speaker 2 asteroid off course by making something crash into it. And also it's not going going to wipe out life on Earth.
That's an upside to happen.

Speaker 5 Yeah, that's also a flex.

Speaker 4 Dar O'Brien's coming in, he's going to wipe out the Earth is not good.

Speaker 2 I think you'd get one really good week of publicity out of it.

Speaker 3 After that, it's downhill.

Speaker 2 Honestly, I'd be booked on everything.

Speaker 2 Graham Norton finally returned my calls.

Speaker 2 Ahui ever going to run out of mysteries in space?

Speaker 3 Nah.

Speaker 4 I mean, I can't see how he can. Space is everything apart from planet Earth, and that is a very big playground.

Speaker 3 It's also expanding, so it is getting bigger. So the mystery density is dropping, but presumably there are more bubbling up out of the quantum ether.

Speaker 5 We're getting bigger telescopes, right? So that means that we are detecting new mysteries that we couldn't see before. So as long as we keep building bigger telescopes, we'll get new mysteries.

Speaker 2 Your racket is going to keep going for a while, then, isn't it, guys?

Speaker 3 68 years, still going.

Speaker 2 Okay, for the past few weeks, we've been asking you to send in your questions about space mysteries. And we're kicking off with Arianne in Ireland who asked, what sound do stars make?

Speaker 2 Big shout out to the the literalists who'll go, Oh, space, there's no sounds in space, like whatever. George, why is this a brilliant question?

Speaker 5 Because stars make sounds. They have sound waves traveling through them, and we actually detect these sound waves on the surface of stars.
And the field of study of this is called astro seismology.

Speaker 5 We can look at the waves as we detect them, and it tells us something about how big a star is, or what it's made of, or how dense it is.

Speaker 5 Unfortunately, because of the vacuum of space and all, those sound waves can't travel to us as sound waves, but you can detect them still still by looking at the light it makes the star wobble it makes the star light wobble so it's pretty cool and do we ever turn those measurements into a sound wave we can hear yeah absolutely so you know a really good way to interpret anything that's a wave um is to use a process called sonification where you just take any wave and you say this is what it would sound like if it was a sound wave of the same kind of shape and frequency so yeah sonification of stars is definitely a thing you've brought in some different forms of intergalactic audio

Speaker 4 maggie what did you bring in i wanted to actually go for something that is actually a sound.

Speaker 4 The Cassini-Huygens space mission was a mission to Saturn. And Cassini went in orbit around Saturn and got some great data.
But Huygens was a little probe, and it actually landed on this moon, Titan.

Speaker 4 And as it fell through the atmosphere, because there was a medium to carry the sound, we could actually listen to it. And I think this is a small section of the end as it actually sort of lands.

Speaker 2 So I am, as always, in these situations, wary of building it up too much.

Speaker 3 I know.

Speaker 3 I know.

Speaker 2 I've not heard this, but I'm taking a wild guess that

Speaker 2 probably imagining something maybe more majestic than we're about to play here.

Speaker 3 That's going to be right.

Speaker 3 It's okay.

Speaker 2 Yeah, okay. So, this is the sound of the Huygens probe landing on Titan.

Speaker 1 Manage your expectations, everybody.

Speaker 2 That was not what I was expecting at all.

Speaker 4 So I think there's the last sort of few minutes as it sort of lands and settles on Titan. But it is a real sound, which I find really exciting.

Speaker 1 That was very good.

Speaker 3 That was very good.

Speaker 5 Can we turn this into a competitive thing?

Speaker 3 All right. I'm giving that a seven out of ten.

Speaker 1 All right, George, what sound did you choose?

Speaker 5 Can we hear mine first and then see if you can figure out what it is?

Speaker 3 Oh,

Speaker 3 okay.

Speaker 3 Okay. Test camper.
All right.

Speaker 2 Okay, here it is.

Speaker 1 Was it a space elephant?

Speaker 3 No.

Speaker 2 Was it a buried choir?

Speaker 5 To me, that sounds like utter despair. Yeah.

Speaker 2 It's not an upbeat noise.

Speaker 5 Right? Yeah, it's nowhere near as upbeat as Maggie is. This is actually the sonification sonification of a black hole at the center of a galaxy cluster.

Speaker 5 And so, like, if you can picture those really cool images that we have of black holes, what they've done is kind of like swept around and made the profile of the wave into a sound.

Speaker 5 So, this is the sound of kind of sweeping around a black hole. And it just sounds like the despair at the end of the universe.

Speaker 3 Absolutely.

Speaker 2 Actual noise of spaghettification. Yeah.
Yeah. As something's been ripped apart by a black hole.
I mean, you're not going to to be upbeat in that situation, are you?

Speaker 5 No, exactly. It's the right kind of sound for it.

Speaker 1 Yeah. Hey, you know what, George Nothing says night entertainment, like

Speaker 3 the impending death of falling into a black hole. So, you know, I'm going to give you an eight out of ten.
So did I? I can 8 out of 10.

Speaker 4 Damn, upbeat and check.

Speaker 3 Never mind. Oh, sorry.

Speaker 2 The sense of existential despair that we're going from that was too good.

Speaker 3 Chris, what did you bring? Well, I thought we'd go from the grandest and most important sound of all.

Speaker 3 So just after the Big Bang, when the universe was in a hot, dense state, there was enough matter around that you could have sound waves propagating through the universe.

Speaker 3 And we can still see the effects of this in something called the cosmic microwave background, which is the oldest light of all.

Speaker 3 So, we know what sound waves were there, and we can work out what the spectrum is. And so, that means we can play the whole universe as an instrument.

Speaker 3 And so, that is the big sound. He's built it up.
He's built it up. Go on in.
So, this is the whole universe as an instrument.

Speaker 3 Good, is it? It's sort of space ASMR.

Speaker 3 So, the reason it sounds terrible is that you had all these frequencies at once. So, the point is, the universe didn't just have one

Speaker 3 note playing, it was all of them. So, you get this sort of white noise, but that was the whole universe.

Speaker 1 Well, 10 for honesty.

Speaker 3 Go for sound. I think you oversold it.

Speaker 2 I think George wins in that round.

Speaker 3 I think George wins, do you agree, everybody?

Speaker 3 Yeah, very good.

Speaker 3 Very good.

Speaker 1 Yeah, absolutely fascinating. Alright, next up we've got a question from one of our younger listeners.
See what you make of this.

Speaker 6 Hello, my name is Molon, I'm 11 and I live in Croydon.

Speaker 6 My curious question came to mind when I was watching a YouTube video about the edge of space and I thought it was an interesting but complex subject. What is the edge of space?

Speaker 6 What's it made of and how can we perceive it? Space must have an edge if it's expanding right, but then how can it be infinite?

Speaker 3 Deep, deep.

Speaker 2 Okay. Marlon is already the boss level of the universe.

Speaker 3 No.

Speaker 1 All right, Maggie, then, what is the edge? I mean, give us like at least a rope barrier and a bounce.

Speaker 3 Yes. You know what I mean? That's it.
That's what I want.

Speaker 4 The answer is we don't know.

Speaker 3 There.

Speaker 4 So, but I think it's trying to understand sort of the concept of the universe. Our current understanding of the universe is it began with something called the Big Bang.

Speaker 4 So it's sort of a singularity expanded out to create space and time.

Speaker 4 And so if you ask what is beyond space and time, it's a very hard concept to grapple. And so we don't really know what it's expanding into, we don't know where its limits are.

Speaker 4 And with things like the James Webb Space Telescope, we look at sort of light coming from the early universe, but we can't go beyond that because the light won't reach us if you see what I mean.

Speaker 4 So yes, we are limited in what we know and what we can see, and we believe it's expanding outwards, but into what we have no idea.

Speaker 1 Any guesses though, Chris?

Speaker 3 Well, we do have this edge edge to the observable universe.

Speaker 3 So as long as you're a practical astronomer, this question is easy to answer because the edge of the observable universe is the bit whose light is only just reaching us.

Speaker 3 So we can see the bit of the universe which in the last 13.8 billion years has had time to send us light. And that's, you could put a line around that.

Speaker 3 If we froze the expansion of the universe, we can say what part of the universe that is. The problem is that we think that's a tiny fraction of the whole.
Why?

Speaker 3 Because various features of our universe make more more sense if it's a tiny fraction of the whole.

Speaker 3 So, for example, if you cut the universe in two, if you pick any angle and you just slice the universe in two, the top half will look much like the bottom half.

Speaker 3 Everything we can measure about the top half on the largest scales matches the bottom half. So we seem to have this uniform universe.

Speaker 3 And that makes much more sense if we're a tiny part of a whole, because you wouldn't expect large-scale variations. So it's a guess, but the guess is that we live in this tiny fraction of the whole.

Speaker 3 So we've got this little bubble that we can see that has an edge. But the whole thing, well, that could easily be infinite.

Speaker 3 And the thing that's impossible to get your head around is the idea that our universe could have started in this Big Bang, this point in time,

Speaker 3 but it could have been infinite then and it could still be infinite now, and it's expanding ever since.

Speaker 3 And I get asked this question almost every time I give a talk, and I don't have an intuitive answer to it. It's just the maths tells us that.
Wow.

Speaker 1 Great question. Unsatisfying answer.

Speaker 3 Yes.

Speaker 2 So essentially, there's a fog around us. We have a torch.
We can shine the torch

Speaker 2 so far, and so the limit of how far we can shine the torch is our observable universe, but what's in the fog area outside, we have no idea. We have no idea.

Speaker 3 We assume it's the same because we assume that we've got a representative sample. But it's possible that the universe could on very large scales be very different.

Speaker 3 There could be empty bits or very dense bits or so on. But we have to assume that our bits typical, because otherwise we can't make any progress.

Speaker 2 Can I ask a related question? Because we had a lot of cosmological questions. This one is from Stephen.

Speaker 3 Hello, Hannah, Dara, and Sky at Night team.

Speaker 8 This is Stephen from Glasgow. When everything was created in the Big Bang, it all exploded outward and is still going.

Speaker 8 So, why is the universe not shaped like a big doughnut with nothing in the middle?

Speaker 2 Yeah, that's because there's no central point, presumably. There's no one central point that we pushed away from.

Speaker 4 I think the idea of an explosion is a bit of a misnomer, a bit of a misunderstanding.

Speaker 3 You have been saying explosion for 80 years now. You've been going over it.

Speaker 3 You chose the name, you

Speaker 3 rapid expansion.

Speaker 5 Rapid expansion, not explosion.

Speaker 4 No, you see, it's explosion, and flyers are.

Speaker 4 And you're sort of the matter starts here and then it's thrown outwards.

Speaker 4 But I think this is sort of the singularity expands rapidly, but it expands outwards. So it isn't like an explosion where all the matter that was there is thrown outwards.

Speaker 4 The matter itself is expanding outwards. So then it's less likely to be a donut, a toroid.
It's more likely to be a continuum expanding outwards.

Speaker 3 So people sometimes talk about if you have bread in an oven and it expands, you think about if there are raisins in the bread, the raisins get further apart.

Speaker 3 Of course, the bread has an edge, so that's not a great analogy. But on the name, the BBC is to blame for the name, the fact it's called the Big Bang.

Speaker 3 In this very building, Fred Hoyle in 1948, I think, Fred Hoyle was a Cambridge astronomer who didn't believe in the Big Bang theory.

Speaker 3 And he gave a talk about modern cosmology on the radio and he wanted wanted to disparage it. So, he said, This Big Bang theory, and the name stuck.

Speaker 3 So, it was actually named by the theory's opponent, so it's his fault. Probably in this room,

Speaker 3 yeah, yeah, yeah, but it but it's so memorable, so it stuck in in the 90s.

Speaker 3 Um, an American Astronomy magazine got so fed up with this explosion problem that they had a competition for people to suggest other names for the Big Bang. And about

Speaker 3 the

Speaker 3 10,000 people wrote in, and at the end, they had an expert panel judge them, and they decided that Big Bang was the least worse name.

Speaker 3 And so Big Bang won with horrendous space kablooey was second, which still has the explosion problem.

Speaker 3 Yeah, so it's not an explosion, it's a stretching of space.

Speaker 2 A donut is different to a sphere because its curvature is different. We can estimate the curvature of space.
Is it doughnut-shaped?

Speaker 5 Well, there is such a thing as the toroidal universe theory.

Speaker 2 Terroidal as much as you want.

Speaker 3 Collapse.

Speaker 5 Okay, so let's, yeah, let's call it the doughnut universe theory. Like, there is a theory about this, right? The four-dimensional fabric of space-time, people do actually research.

Speaker 5 You know, is it flat? Is it curved? And if it's curved, is it like a saddle? Is it open? Is it closed?

Speaker 5 And some people think that it might be shaped like a donut, a torus, which is pretty cool because then it means that like as you travel through the universe, eventually you'd come back in yourself, like if you're inside a video game, and it's like, you know, you can kind of go in a loop.

Speaker 3 But it's important to say that we know that if it's a donut it's a very big donut and that we live only on a small part of the donut.

Speaker 2 So we're not ruling out the donut.

Speaker 3 We're not, but when we measure whether our space is curved, the bit of the universe we can see is pretty flat.

Speaker 3 And so therefore for it to be on a donut, we have to only have a tiny bit of the donut.

Speaker 3 In the same way that if we were on a sphere, we must be on a tiny bit of the sphere so we don't notice the curvature.

Speaker 3 So you can have these exotic shapes, your donuts or your crumpets or whatever it is that you want the universe to be like,

Speaker 3 but we only see a tiny bit of it.

Speaker 2 Are we eliminating that we would be able to, like an ant on the football, walk all the way around it and find ourselves back at the same point?

Speaker 5 So I mean like like Chris says we can't fully rule it out but it's really unlikely because you know everything that we look at so far it looks like space-time is flat.

Speaker 5 So either the universe really is so much bigger than we can even imagine or it's flat as a pancake so we should go for pancake universe.

Speaker 3 I really like the idea that in maybe a hundred years time people would be sitting in this theater and going, no, they call it a pancake universe because the BBC

Speaker 1 absolutely okay so maybe a donut maybe a pancake definitely some sort of baked good all right um we have another question here this one came in from Keith

Speaker 9 Hello, my name is Keith and I'm from Liverpool.

Speaker 7 My question is, what would happen to the universe if the speed of light were to increase or decrease?

Speaker 7 This came from a discussion about how disappointing it is that physics seems to rule out interstellar travel.

Speaker 7 Then we thought, if light traveled more quickly, space travel would be faster and engines would be more powerful. But I suspect it would have some downsides too.

Speaker 2 I love the dryness of that.

Speaker 3 I mean, it might have some downsides. It would change one of the fundamental constructs of the universe.

Speaker 2 Like, everyone goes, there's been to be some causation that what would happen to the universe if it were to increase in degrees?

Speaker 2 And actually, if it were just different, in what way would our universe be different?

Speaker 4 So what Chris was talking about, sort of this sphere of things that we can look at, because it takes a finite time for light to leave them and travel to us.

Speaker 4 That's sort of the envelope we're seeing at the moment.

Speaker 4 Now, if we change the speed of light, of course, if we make it bigger, then that light can travel from further afield, so we can see more of the universe.

Speaker 4 If you make it smaller, then that sphere gets smaller because the light takes longer to get to us. But also, as you say, it is one of the fundamental constants of the universe.

Speaker 4 And as a physicist, we rely on this because otherwise, what else do we have?

Speaker 2 Yeah, but is there no reason for it to be three by ten to the the 8 meters per second?

Speaker 3 No, we don't know why the speed of light is what it is. It's just, we know relativity requires that it be constant.

Speaker 3 But the real problem, to answer the question that we got, if you change the speed of light, you upset the balance of forces that keep stars together.

Speaker 3 Because stars are in this constant battle between gravity pulling them together and light generated at the center pushing outwards.

Speaker 3 So if you upset that, even by changing the speed of light a bit and some of the other constants a bit, then stars don't exist. So that's bad for the universe.

Speaker 3 However, it would make for better science fiction.

Speaker 3 I have to tell this story because this instinct from the questioner that everything would be more fun if we could travel faster than the speed of light is spot on.

Speaker 3 And there's a great story from the early days of Star Trek where Gene Roddenberry, the producer, got this letter from a fan which said, look, I don't really understand what happened because on episode one, the shuttles moved at this speed, and then three episodes later, they could go faster.

Speaker 3 So what is the maximum speed of a shuttle that the Enterprise carries? And Rodenby wrote back and said, it's very simple. The shuttles travel at the speed of plot.

Speaker 3 And so, as a physicist, I think that's the fundamental rule of the universe.

Speaker 1 So, let me make sure I understand this then. So, speed of light, slightly slower, bad, nothing we know or love exists.

Speaker 1 Slightly faster,

Speaker 1 bad, nothing we know or love exists.

Speaker 3 If you don't change gravity as well,

Speaker 3 the balance between the two.

Speaker 1 Current speed, inconvenient for science fiction.

Speaker 3 Yeah.

Speaker 3 That's why we need to change it.

Speaker 4 We can find workarounds. There are sort of ideas like how Cubier Drive, for instance, where you keep still, but you walk space and time around you, takes huge amounts of energy.

Speaker 4 So we're not doing it tomorrow, but there are ways of sort of wormholes and all sorts of lovely ideas which science fiction lean into beautifully.

Speaker 2 Yeah, because I've never got from people who actually work in this field that you sit in cinemas cutting loud hit the screen, going, well, that wouldn't happen.

Speaker 2 You know, that wouldn't happen. Did you know that? And like shaking up the people beside you, going, this is nonsense.

Speaker 3 Yeah.

Speaker 2 You don't do that anymore than anyone else does. Like, whatever.
You presumably enjoy a science fiction rump the same as anyone else.

Speaker 4 I can suspend my disbelief unless it's really, really painful.

Speaker 5 Do you object? For me, it's just the messing with physics. Like, if we're doing straight fantasy, like, you know, if there's people who fly, if there is magic, that is fine.

Speaker 5 I just don't want them to interfere with physics.

Speaker 1 So fine with the impossible, just not with the implausible.

Speaker 3 Yes, exactly. Do you know what to know what the best astronomical blooper of all time is in a film? The kind of thing that would get me nudging the person next to me in the cinema?

Speaker 3 In Titanic, when the Titanic's sinking, they picked a random sky background, and so you can work out that it's April and they're in the Caribbean based on the stars,

Speaker 3 which completely changes the film.

Speaker 1 I think Neil deGrasse Tyson complained to James Cammon about precisely that.

Speaker 3 And they did a new director's cut with the correct sky yeah yeah because that's the length you go to to shut up the person in the cinema going did you know the stars are right fine we'll change things there you go

Speaker 1 well you started off by saying you're a part-time alien hunter and so we obviously cannot do a show on space mysteries without talking about aliens here we go

Speaker 9 hello it's richard from whitley bay Venus and Jupiter are deemed unsuitable for life, but aren't there points in the upper atmospheres where the temperatures and pressures are similar to where life is found on Earth?

Speaker 9 Could airship drones be sent to look for exotic simple forms of life?

Speaker 2 So there's two parts to this. Might there be exactly life forms in these planets? And also, how would we find them?

Speaker 2 He mentioned, George, what exactly are airship drones and why would we be sending them to Jupiter or Venus?

Speaker 5 I think a balloon. They're kind of robotic and you can operate them like drones remotely.

Speaker 5 And actually, I think NASA are planning something like this for Venus at least because they want to measure what's there.

Speaker 5 And the question is actually, right, there are areas where the temperature and pressure might be kind of Earth-similar.

Speaker 5 So, at least for Venus, people were talking about maybe some microbial life having colonized the atmosphere.

Speaker 5 I think the issue, though, maybe with sending something like this to Jupiter, is that it very rapidly, like the pressure gets out of hand. So, you know, the whole thing would just

Speaker 5 like you've also got to be careful. It's a bit acidic.
So, yeah, you've got to design your airship drone pretty carefully.

Speaker 1 I mean, you're basically trying to float a hot air balloon over a death planet. That's it.

Speaker 3 A little bit, yeah, yeah, yeah, a little bit. But there is this layer in Venus's atmosphere, which is about room temperature and pressure.
It's still acidic, as you say.

Speaker 3 And that's the layer that Jane Greaves a few years ago announced that she'd found a chemical called phosphine in. And phosphine on Earth is made mostly, frankly, by penguins.
It's a biosignature.

Speaker 3 It's made by life. It's in penguin poo,

Speaker 3 amongst other things. And so the fact that we found it on Venus, maybe it's the product of some volcanism or some weird chemical process, but it could also be life hanging on in this Venus penguin

Speaker 3 very very small Venus penguin Venus penguin is heart specific

Speaker 3 yeah

Speaker 3 so there are these these regions and it makes you wonder about what it is when we say we need conditions like Earth does that count you've got room temperature and pressure but it's acidic in Jupiter we rule it out because there's no oxygen but it'd be nice to to believe that life was creative enough well actually but the thing is um life could be so varied or so different from what we anticipate.

Speaker 4 In fact, just to name-drop, I did have this conversation with David Attenborough once.

Speaker 3 Sure. I know,

Speaker 4 as you do. I feel terrible because I was having an argument with our national treasure and saying that I don't know if we actually need water for life.

Speaker 4 Life as we know it, yes, but maybe not life not as we know it.

Speaker 4 Now we're looking at some of the moons of Jupiter and Saturn, and that's because we found life in places like the Mariana Trench, 11 kilometers below sea level, where sunlight can't penetrate.

Speaker 4 So we thought there could be no life here. So I think we need to be very careful how we define life.
There might be a whole variety of life that we just don't anticipate.

Speaker 3 I don't want microbes though.

Speaker 1 I want little green men.

Speaker 3 I know people to talk to, basically. This is the job.

Speaker 3 Well, I think one of the interesting things that's happening is we, if you think about an astronomer looking for life in the universe, that comes from a logic about deliberate communication.

Speaker 3 And what we're trying to do now is look for sort of accidental evidence for life.

Speaker 3 You know, if there's a civilization that's built giant solar panels orbiting their star, can we see the effect on the star? If they're mining their asteroid belt, can we detect that?

Speaker 3 All of these, they're called techno-signatures. And looking for that, gives us a new way to try and imagine how we might find life.

Speaker 1 Because I guess there is a conundrum there, right?

Speaker 1 That when we turned on the satellites, when we turned on the opportunity to listen into space, it was strange that there wasn't a cacophony of sounds.

Speaker 3 Yes, I think the space age was a bit of a disappointment that we found that Mars just had craters, that Venus was this hellhole, and so on.

Speaker 3 And I think people just expected it to be obvious that there was life in the cosmos. And it's not, but the universe is a big place.

Speaker 2 Actually, just a tiny sort of diversion. Last time I met David Attenborough,

Speaker 2 I was, no, no, because we were both doing the pre-Christmas selling books on radio interviews, and we're sitting in a waiting room radio too. And I had some kids' book out

Speaker 2 about space. And when he sat down, we were chatting.
And I said, by the way, I should tell you, the book I've written, yeah, it has some stuff about animals in it.

Speaker 2 And Attenborough genuinely leaned in and went, went, you have planets, I have animals.

Speaker 2 Look, one final proper question there.

Speaker 3 We've all traded our Attenborough stories.

Speaker 2 If you were given unlimited funds to try to find life, where would it be?

Speaker 5 So I would make a really big telescope and I would aim it at one of those lovely exoplanets we've been working so hard to discover in the habitable zones of their stars.

Speaker 5 So far, we've not found a single one of these kind of rocky ones that actually has an atmosphere. But, you know, once we do find a photos.

Speaker 2 In the hope that we would see the gases in the atmosphere that we've got.

Speaker 5 Yeah, so we'd be looking for biosignatures, definitely.

Speaker 3 Penguin farts.

Speaker 5 Yeah, exactly.

Speaker 5 We want to find phosphine on a rocky exoplanet.

Speaker 2 What if the penguins have been holding it in?

Speaker 3 They're floating.

Speaker 5 I mean, so that it is.

Speaker 2 Or they only poo on the other side of the planet.

Speaker 3 Damn.

Speaker 5 We find a planet that's rotating and isn't idly locked with a star.

Speaker 3 Sarah, you know, you started this by saying, are there always more mysteries in space? I think we've found some new ones.

Speaker 2 That is almost all we have time for.

Speaker 2 Have we solved anything anything solving?

Speaker 3 No, no.

Speaker 3 That's astronomy.

Speaker 2 Do we ever really solve anything?

Speaker 1 But look, they've been going for 68 years. They need to go for another 68.
So that's fine by me.

Speaker 3 There, absolutely.

Speaker 2 On that note, a huge thank you to our curious questioners, our wonderful audience here at London's BBC Radio Theatre, and of of course our fantastically starry panel of sky at night presenters george dransfield chris lintott and maggie adarin pocock

Speaker 2 subscribe to curious cases on bbc sounds and make sure you've got push notifications turned on and we'll let you know as soon as new episodes are available

Speaker 3 Who's in the news for all the wrong reasons?

Speaker 10 Step inside the world of crisis management and so-called spin doctors with me, David Yelland.

Speaker 11 And me, Simon Lewis. In our podcast from BBC Radio 4, we tell you what's really going on behind the scenes as the week's biggest PR disasters unfold.

Speaker 10 Simon and I used to be on opposite sides of a story in the media when I was editor of the sun and Simon was communications secretary to the late Queen.

Speaker 10 Now we've teamed up to share everything we know about what's keeping those big stories in and out of the press.

Speaker 11 As the great philosopher King Mike Tyson himself once said, everyone has a plan until they're punched in the mouth.

Speaker 10 And there's a lot of people punching people in the mouth in this town.

Speaker 11 Listen and subscribe to When It Hits the Fan on BBC Sounds.