The Infinite Monkey Cage - The Universe: What Remains to Be Discovered?

Episode Date: August 1, 2016

Brian Cox and Robin Ince take to the stage at the Blue Dot Festival, at the home of Radio Astronomy, Jodrell Bank. They are joined on stage by Ben Miller, Charlotte Church, Dr Paul Abel and Professor Tim O'Brien to explore the big questions that are still to be answered about our Universe.

In our new podcast, Nature Answers, rural stories from a changing planet, we are traveling with you to Uganda and Ghana to meet the people on the front lines of climate change. We will share stories of how they are thriving using lessons learned from nature. And good news, it is working. Learn more by listening to Nature Answers wherever you get your podcasts. Hello, I'm Robin Ince. And I'm Brian Cox. And welcome to the podcast version of the Infinite Monkey Cage, which contains extra material that wasn't considered good enough for the radio. Enjoy it. Thank you.

This is the Blue Dot Festival and this is the Infinite Monkey Cage. This is the first time for quite a while that Radio 4 have done a panel show in an open field. Not actually. You remember Parsons at Woodstock? There was Nicholas Parsons at Woodstock. Some of the older people here will remember that, of course, halfway through the Who set, Nicholas walked on and said, I have to admit, I am going to give the both deviation and hesitation

there for trying to put us down. That was a correct challenge, the Grateful Dead. You have 17 hours now on my generation. Quote, unquote, Reading 97. Quote, unquote, Nigel Rees and

Daphne and Celeste, of course. A lot of people forget about Nigel Rees being there, but thees and Daphne and Celeste, of course. A lot of people forget about Nigel Rees being there, but the reason that Daphne and Celeste were bottled off was due to a poorly thought quotation from GK Chesterton. I've got to say to you, not to spoil the myth or anything, but I said, I'll make some jokes up, say anything. So I could say, kind of, you and yours, Donington. Yeah, you and yours, I think, Donington, Monsters of Rock.

We're joined by Lemmy to talk about tinnitus. Lemmy, Lemmy, Lemmy. Gardener's Question Time, Oasis, Nedworth. Classic. Gardener's Question Time, opening for Oasis, a lot of questions about things that grow in the garden, many of them not legal. So this is the first time that we have done the Infinite Mung Cage

in an open field. We have done festivals before, but basically you can't... How many of you have actually been to Jodrell Bank before? Isn't the Lovell Telescope one of the most beautiful pieces of human imagination turned into a structure to interrogate the universe that you've seen recently? We actually stood right in the middle of the dish, didn't we? What, it was about six months ago? Yeah, for our Einstein programme.

We did this programme about Einstein. And afterwards, we're sitting in the canteen, and I asked Brian to explain a little bit more about general relativity, and he did it very beautifully. And someone had gone to go and get him a pie, because that's how famous he is. He doesn't have to get his own pies, they're brought to him. And he leant forward, still smiling,

bit into the pie and went, Ow, ow, ow, it's's boiling it's boiling right which i thought was very beautiful because there's something wonderful about seeing a human being who understands the idea of the heat death of the universe but not the speed of the cooling of a pie so it was great though it's such a beautiful structure. It is a beautiful structure. The fact that it can see out to the edge of the observable universe as we talk about 13 billion light years away, it's a tremendous thing. I'm not going to give it away though.

Maybe we should start. What we're going to be talking about is what we are yet to find out about the universe, what we still need to know about the universe. So the official title is, The Universe What Remains to be Discovered, brackets, not dark energy or dark matter, close brackets. Because fans of Monkey Cage will know we've done that about six times, and so our producer said we're not allowed to talk about dark matter and dark energy.

Dark matter is 70% of the energy density in the universe. Dark, sorry, dark energy is 70%. Dark matter, yeah. Do not tell anyone you saw that! It's the most secret thing! Oh, my God! What a brilliantly knowledgeable crowd this is! Dark matter is 25%.

So we've got about 4.9% of the universe that we're restricted to talk about, but we'll make a good... There's another reason we're not going to talk about dark energy, because even after every show we've done about dark energy, people have gone, well, what exactly is dark energy? And you've gone, yeah, it's a little tricky, that one. It's a little tricky. So we have

a great group of people. Again, Ledger, and please welcome to the stage Associate Director of George Orwell Bank, Tim O'Brien, Astronomer Paul Abel, Actor andauter Ben Miller, and singer and songwriter Charlotte Church. And we're going to open with Hotel California. So, Paul, we look like some horrendous Boyzone tribute act.

So we will get... This is, as I said, it is quite a bizarre thing. We've never done this. We are doing it properly. Well, as properly as we've ever done it. But it's going to be a discussion about what we have yet to find out about the universe. And so we'll start off...

Well, in fact, the music that you heard when we came on is a fantastic recent piece of music called Hello Moon, but it is not merely music. And Tim, Tim O'Brien, I want to ask you, tell me a little bit more about why an audience here at Jodrell Bank in the shadow of the Lovell Telescope, why they should be fascinated by what they heard as we walked on. Because somewhat bizarrely, maybe that dance track is made up of a remix of space sounds, some of them recorded with this telescope. So the beat, the thud that you hear

is actually the thud of pulsars, the flash of stars that exploded thousands of years ago. They spin like cosmic lighthouses hundreds of light years away, and we detect the flashes with the telescope, take those radio flashes and turn them into a sound. And that sound gives that rhythm that we then built into that dance track. You should perhaps describe pulsars in more detail because they're fascinating objects in their own right.

Yeah, I mean, they're basically things that are about the mass of the sun, so about one and a half times the mass of the sun, but only about the size of a city, so only about 20 kilometres across. So if you can imagine getting a giant pair of oven gloves or something and getting hold of the sun and squashing it down to the size of a city, that's a pulsar. Mass of the sun, 20 miles across or so, rotating how fast?

Well, some of them rotate, the fastest ones rotate more than 700 times a second. So it's something, the mass of the sun, the size of a city, spinning more than 700 times a second, radiating out sort of beams of radio waves from the magnetic poles, and as those beams sweep round, just like a lighthouse, you get a flash, flash, flash, flash. And if we look at the Hubble telescope over there,

how distant are the pole stars that you can listen to? So they range from a few tens of light years away to several thousand light years away. So the radio waves we're picking up with that telescope have taken, in some cases, thousands of years to reach us, travelling at the speed of light, 300,000 kilometres every single second. Well, Ben, your most recent science book is about trying to define what life is and indeed looking at it as well from the perspective of possible extraterrestrial life. Now talking about pulsars, Justin Belbanel, somebody initially what was called LGM1 and I wonder if you can give us a little bit of background of why a pulsar may have been given the tag LGM1.

Yes, well, this is a brilliant story, dating back to a time when we were first switching on our radio telescopes and starting to look at the sky. And of course, we just didn't know really what we might find. And one of the possibilities was a signal from an alien civilization. What if there was an alien civilization out there with radio telescopes broadcasting some kind of signal? So I think this was something that all radio astronomers of the time were aware of. And Jocelyn Belbanel, as you say, set up a radio telescope. This was in the late, about 1967.

She was doing her PhD, actually, and she was looking for a special type of very active galaxy called the quasar. She built this very sensitive, for the time, radio telescope, and she was there at night, and she had the chart recorder paper because there was no sort of electronic instrumentation. You know, this was like a proper good old-fashioned chart recorder going along. And she began to notice when she

looked at the readout, there was about two centimeters of what she called scruff that appeared on the paper, which was this very, very intense signal. And of course, then she lay in wait. And one night, she managed to be there just at the right time to switch the chart recorder pen so that it could really pick up the detail of the signal, and it was a pulse, which is exactly what you might expect if an alien civilization had set up some kind of beacon, some kind of lighthouse, some kind of indication,

here we are, come and have a chat. So they called this source LGM after little green men. It was slightly tongue-in-cheek, I believe, at the time. But there was a very real possibility. And Jocelyn Belvenel was furious because she needed to get a PhD out of setting up this experiment. And she felt absolutely gutted

because some alien civilization had decided to signal to her exactly the frequency she was looking at and ruined her experiment. But I remember we do Stargazing Live here, as some of you might know, and we had about three or four years ago now, wasn't it, when we discovered a planet in the Kepler Space Telescope data,

and we asked Tim, we were all sat there going, it would be brilliant if someone had a radio telescope. I don't know, there's that one. And Tim said, yeah, okay. So we swung it around to this planet. And then at some point, the BBC said, what happens if we detect a signal in the broadcasting regulation? Does it say we're allowed to do it?

We asked Tim. We had to go and look at what to do. What would a radio astronomer do? What would you do? You're director of this telescope. If you heard a signal, would you immediately go on Twitter? There are aliens out there. Well, OK, probably. Officially.

But officially. In fact, we would want people to know, right? So we would not keep it secret. Wel, oes. Efallai. Yn y ffordd, byddwn ni am bobl i'w wybod. Felly byddwn ni ddim yn cadw'r pethau'n segredig. Mae pobl yn meddwl bod rhai o'r seicrwydd swyddiol wedi'i anfon ar rywun sy'n dweud, os ydych chi'n detegu arwain, peidio â ddweud i unrhyw un fod yn panic. Nid ydym wedi gwneud hynny. Nid yw unrhyw un yma wedi'i anfon hynny. Byddwn ni am bobl i'w wybod, oherwydd byddai'n beth mwyaf anhygoel y byddwn ni wedi ei ddysgu. Ond beth fyddwch chi'n ei wneud yn gyntaf yw gwirio a oedd e'n iawn. incredible thing we'd ever discovered. But what you would do first, actually, is check you got it right. You would actually think about it in the same way that the people at Cambridge, Jocelyn and Tony Hughes,

those people, they looked at it and thought, they didn't name it that, but they thought, you know, is it really aliens? And they thought about it for months and they kept it quiet for months because they wanted to check what was going on. So there'd be a period of checking, you'd get your mate with another telescope to have a look, see whether they could see it. But then, actually, you'd, you know, I think what we'd do, in fact,

I had somebody else ask me this question quite recently, what would we do? And it's not really written down. So we'd be inventing it as we went along, to be honest. And we'd say, okay, is it real? We'll go to the International Astronomical Union. We'll tell the union and see what they think. So it's an amazing thing.

There's no protocol. There's no signed-up protocol. I think we looked, and the only people we could find who had a protocol were Vatican City. But they had some regulation, didn't they? You ring the Pope. So I don't know whether it's comforting or not that we don't have a protocol for what to do if we pick up aliens.

Is it comforting? I just like the idea that if you had broadcast that on Stargazing, that the second signal you'd get from extraterrestrial life would be a cease and desist letter having sued for they've invaded our privacy on Andromeda. Yeah, or something like going, that Darrow green's always on. Yeah. Charlotte, the first time, in fact, the very first time that we met was at another music fest, End of the Road,

where at one point you were watching Sufjan Stevens and singing along and someone turned to you and said, you've got a nice voice. Yeah. And you just said, thanks very much. But the first conversation we'd never met before is you kind of came up to me very quickly in a glittery outfit and just went, I love physics! Yeah. And, you know, people know that obviously you've been interested in such a broad variety.

What was it about physics? What is it that drew you into kind of the world of things like cosmology? Do you know what? It happened when I was at a newsagent's and I was buying some completely pointless, worthless celebrity beauty magazine thing. Ac fe ddigwyddodd pan roeddwn i ar agenwyr llyfrgell a chael rhai pethau o ddim yn ddigon ddiddorol, gweddill, celfyddydau, magasin gweddill, ac fe wnes i weld copi o'r gwyddonwyr newydd a meddwl, beth ydw i'n ei wneud? Pwy ydw i? Rwy'n mynd i gael fy ngwneud. Ac fe wnes i newid fy fywyd. Roeddwn i'n gwbl yn hynod o'n ffasynol gan bob beth yn ymwneud â hynny. Ac fe wnes i'r syniad o ddysgu am yr holl bethau hwn.

Roedd yn bosibl nad oedd rhaid i mi fod yn boffin iawn neu mynd i'r brifysgol i fod yn ddiddordeb ac i gallu addysgu fy hun, hyd yn oed ychydig, am y cysylltiadau mawr hyn. Ond hefyd, fe wnes i ddod o hyd i amrywiaeth o ffwrdd, yn rhywbeth, yn ymwneud â pethau fel mecanigau cyffredinol a sut anodd rhai pethau immense amount of comfort somehow in this, you know, especially when it comes to things like quantum mechanics and just how odd some things about our universe and reality and some of these huge ideas, these mind-bending ideas, I found loads of comfort in. Do you remember the first, because there are certain facts

where you just think this is a good entry point for anyone who doesn't think science is for them. Like recently with gravitational waves, I was reading a piece by marcus chow and when he was talking about the point of the merging of the two black holes and at that point of merging the power output would have been the equivalent of 500 times the power of all the stars in the universe that's a really good opener if someone's not interested in that you go we won't be needing to ever talk to you again because it so was there an idea that you just saw and you thought what this changes so much i think for me it was it was the idea of entanglement the idea of entanglement was just like oh that is so cool

it could be how far away um yeah so yeah the idea of entanglement just read but also and i suppose Yn fawr. Felly, ie, y syniad o ddiffygwylio, ond hefyd, ac rwy'n credu bod hyn yw lle mae llawer o nodau cod yn dod i mewn, sy'n gweithio hefyd, i ddysgu. Ond, dim ond, dyma sut gallwch ystyried hynny, efallai fel byd dynol neu, chi'n gwybod, y gwaith dynol emosiynol sy'n mynd ymlaen. Felly, fe wnes i ysgrifennu cân gyda fy marn i ei enw Diffygwylio, sy'n ymwneud â, yn y bôn, fel cân o fawr, ond mae'n stuff that goes on. So I actually wrote a song with my partner called Entanglement, which is basically a sort of like a love song, but it's sort of about two entangled particles as well. We should, Paul, because the main subject of this discussion is things we don't know. Yes.

And that idea, quantum mechanics, the way that that interacts, I suppose, with cosmology in the sense of relativity, that's one of the big things. Perhaps you could start just by giving the one-minute description why quantum mechanics and our best theory, the framework for cosmology, general relativity, doesn't fit together. Right, OK. So a big admission on behalf of all theoretical physicists in this area, we don't have a quantum theory of gravity.

We do have quantum mechanics. It's brilliant. It's the reason why all your mobile phones work. We have general relativity, which is the reason why all your sat-navs work, and they got you here today on time. They both fundamentally disagree on the nature of space-time, and that's really rather embarrassing, because it means you have to sort of choose whether you want to do physics of the very small or physics of the very large. We don't want to have to do that. It's very, very embarrassing to be in that situation. The reason why black holes are key to this is because

around the event horizon of a black hole, we have quantum mechanical effects that are happening as well as gravity. The two have to work there. They have to coincide there. This becomes a very good place to look for a quantum theory of gravity, how gravity works at quantum scales.

And when people started doing this in the 70s, one of the most remarkable results that came out of this hybrid of the two theories, quantum field theory, was that black holes are not static, they're not dead, they radiate slowly over time. And the fact that the smaller the black hole is, the quicker it radiates. So far from being static dead objects, any primordial black holes that may have formed at the time of the Big Bang might now be evaporating.

And as they get smaller, the evaporation process runs away, and they explode in a shower of gamma rays. I mean, in cosmological terms, it's not that impressive, but if one went off in this field, it would be enough to take out us, the stage, and most of this side of the planet. So a bit of respect for them. But these gamma-ray bursts still exist out in the universe.

We don't know if they could be the final death throes of black holes. I think I went over a minute, didn't I? No, no. But, Tim, gamma-ray bursts, they're one of the big mysteries. So perhaps you could describe gamma-ray bursts from an observational standpoint. Yeah, these were things that were discovered in the late 60s, and they were actually discovered by satellites that were put up

to look for people violating the test band, you know, testing atomic weapons. So they were seeing flashes of gamma rays, thinking that they were coming from the Earth, and in fact it was a sort of pantomime, it's behind you moment, because they were behind the satellites

out in the distant universe. So every so often, one of these things explodes, flash of gamma rays. We had no idea what they were for decades. We still don't know exactly, but we do know they're far away. So they're scattered all over the sky. That means they're not in our Milky Way.

They don't sort of track the Milky Way across the sky. They're all over, very distant, probably explosions. Our best guess is that they're explosions of massive stars, supermassive stars at the ends of their lives. By very far away, how far do you mean? Oh, I mean many millions of light years, and probably in most cases billions of light years. So, you know, when we look out in time, of course,

out in space, I should say, the great thing about astronomy is you're seeing back in time. So you've got a telescope that's a time machine. You look far away, you see far back in time. So these things are back a good fraction of the age of the universe. So we're seeing billions of years into the past when these things are out. Well, I want to ask Paul something. Because we were talking about the idea of looking back in time,

we should also cover the notions of time and the debates over our understanding of how we believe we experience time and then time as an idea within physics. Yeah, time in physics is very interesting because we have sort of kind of like have two forms of it. And I think it's probably just me being stupid, but I've never really understood how time in quantum mechanics works it's not really like time in general can anybody help it

I just say that how remarkable this entire event is to be standing on a stage and all these people listening to descriptions of the inability sometimes to match up quantum theory with our understanding of the nature of time. It's not at all what it was like when the stereophonics played in. We should say, have you got now the one-minute version of what on earth you mean by that sentence? What is it about time and quantum theory that's confusing you? Well, it's time in general. I'm going to do it from the other way around.

Time in general relativity is really well described. We know if you move quicker, time moves slower for you and for other people observing you. They have their own measurement of time. But I'm still not clear, really, what time is in quantum mechanics. We need time in there, because it's what we call a unitary theory.

Things happen A, B, C, D, but they have to be time reversible as well. That's another important point. So you have to be able to go back the other way. But we don't see those sort of processes happening on larger scales. Ben, sorry. Is it right to say that in both quantum mechanics

and general relativity, there's nothing to stop you going back in time? I mean, there's nothing within the actual theory. Do you see what I mean? Aren't all processes time-reversible? No. It's actually closed time like geodesics are.

I shouldn't have said that. It's a bit too... The answer's no. I'll try and do it. It's special relativity. It's the fact the speed of light is a constant for all observers. Yes. Ultimately is the thing that stops you being able to go back in time. It's built into the geometry because you then would reverse causality.

But you can't bend that geometry in curved space time. So if you've got a powerful gravitational field, you can bend your future light cone into the past. But we think those space time solutions are not stable. We don't think that it's real. Really, we just frown upon it and hope that there is no such thing. Since nobody's arrived from the future, is that not a good practical... Has anybody arrived from the future? I don't know.

They probably won't say. He's put his hand up. I got shouted at for saying that by a relativist. Because they said, no, because it seems to be true that you can't go back further than the first time machine. No. Well, it depends on quantum effects. Whose past are you going into?

What do we really mean by past, present, and future? Because it's not clearly defined. And I, as again, I've come to slowly believe that my brief foray into this area, that our problems we're experiencing in finding a quantum theory of gravity lies with time. And I think maybe changing it or removing it

or at least some sort of alternative understanding Removing time. That is what he said. Don't say it like that, Ben. It's not weird. Can he do that? Now? No, not now. No, because you can't even define what now is. Don't remove time. Underworld will go on in two hours.

It would be two hours. It'll be a disaster. You didn't have to come up here to be insulted. Yes, you must have heard the show before. It's an interesting idea, though, isn't it? It's interesting, I think, removing time. But it's the most basic thing. It's probably the thing that we find easiest to experience and describe,

and yet physics has no Good description of its diff. What better states or does it? Because you've got the second you know the second law of thermodynamics haven't you you've got me yes. Yes, I'm on chat This is a brilliant audience. I was heckled in heckle What about the fact that entropy always increases in a closed system? Aren't they lovely? I went, I should take more.

And I would hazard, Paul. Yeah? Hazard? Hazard. I would hazard that one of the very canny things about that solution in the 70s was it actually combined the second law of thermodynamics with quantum theory and general relativity all in one go. Because part of the key to the puzzle was defining the entropy of a black hole, right?

Yes, it was. And the whole area, after we realized black holes worked, radiated, created a whole new area called black hole thermodynamics, where we have the equivalent versions of the thermodynamics of all the things we understand translated in sort of a gravity version but there's still problems something's still wrong because one of the big problems we have is something called the information paradox is everyone here familiar with that well that's safe and line this is like the middle of the set for the band isn't? We'll do the popular quantum mechanics at the beginning. We'll close with some really beautiful high cosmology. But right in the middle, we will go for a little bit of it.

Let's try the B-side. So the interesting thing is, quantum mechanics says you can't lose information. If you've got a particle, things like its charge momentum, that can't vanish from the universe. But if you throw it into a black hole, it's gone from the universe. And when this radiation comes off black holes and they evaporate, there's no correlation between the stuff that fell in. So that's just a big violation of quantum mechanics.

Again, something very strange is happening that we don't understand. Can I just check? If I do fall into a black hole, is it true I'll be spaghettified and stretched like I saw in a book? It depends on the size of the black hole and if it's rotating. If it's rotating, a big car black hole, then you might survive the buffeting. But it'd be funny to see you spaghettified.

Well, that's what I just wanted to know if I'd be shot around in a black hole. Charlotte. I just loved it when you said, can I just check? What were you thinking of doing? Well, you know when you've been on a weight loss program and it hasn't worked, and you think, well, maybe if I were taller.

What about the idea that with Hawking radiation, that the two particles are entangled, and so the one would come out of the black hole and the other would remain in, but there's something to do with that can't be possible because the particle can't be entangled with two things. So what does that mean for what you're saying? Yeah, come on. Do you want to go, Tim? No, you go.

I think, you know, just to describe this idea, in quantum theory, so now everywhere, there are particles popping in and out of existence all the time. And you can measure those effects, so we know that's real. It changes the way that light, the spectrum of hydrogen atoms and things, so it's a real thing. But on the edge of a black hole on the event horizon, you can imagine them popping into existence, and before they have time to go away and return their energy to the vacuum again,

one of them falls in. and before they have time to go away and return their energy to the vacuum again, one of them falls in. And that means that the one that's fallen in can't get back to annihilate with this one, and that's what Hawking radiation is. But I think that idea was that they can still be entangled in some way, which means that you do something to this one, something happens to this one, even though this one has gone into a region where they can't communicate. We wondered if perhaps that's how the information might be retained, but no one's

really sure. There's a recent thing called the firewall hypothesis. I think it's rubbish. I don't care for it at all. And you have this idea that... We'll get letters. What? We'll get letters. I'll write them back. The firewall Easter's. I don't mind. They're all over Twitter, the firewall Easter's. Well, they will

now you've put the idea into that, yes. No, I don't... Because part of the over Twitter, the firewallistas. Well, they will now you've put that idea into their head, yes. No, I don't... Because part of the problem with the firewall is that you have to suspend the equivalence principle. And that is at the heart of general relativity, so no. Right, that's the B-side done now. That's the great foot down to the castle. With a fantastic guest appearance from Charlotte Church

halfway through, which is what you want on the B-side. Charlotte, when you're dealing with... What was the moment when you were reading... We're not just the new scientists. Do you want on the B-side. Charlotte, when you're dealing with, like, what was the moment where, when you were reading, we're not just the new scientists, do you have kind of stop-start moments where you get to a certain idea and it becomes so delightful that you go,

right, this is where you stay for a while. You're trying to be kind of, you know, renaissance human across many ideas, but you then go, this particular idea of quantum behaviour, for instance. Well, I was reading something about the idea of the big bounce as opposed to the big bang, which literally made me, like, clap and whoop with joy.

It was amazing and it's sort of so neat and lovely. And it was about the idea that, you know, at the point of singularity, there is no... There is zero mass but infinite energy. And, you know, when that happens, then, you know, you've got... That's the end of, you know, general relativity. And so the idea of trying to circumvent how you get... So you avoid the singularity.

And just reading, like, lots of different people's ideas of how you do that would just... Yeah, it made me have a little whoop. These are questions, Tim, about the origin of the universe, which is obviously a difficult question to answer. But even the origin, we mentioned it earlier, the origin of structure in the universe, which is a very interesting area of study at the moment.

So what came first? We have this idea that there's a big bang, then the universe expands and cools. You get atoms forming 380,000 years after the big bang, but then there's no structure for a long time. And then what happened? The first stars, the first galaxies, black holes, what? I think this is one of the most beautiful ideas at the moment, actually. There are very poetic names for this period in the evolutionary universe. So we can see back

to 380,000 years after the Big Bang. We look at the fading glow of the Big Bang. It's the cosmic microwave background. We can see that and we have spacecraft that map that and we learn a huge amount about the universe at that time. But after that time, as the universe is expanding, it's mostly hydrogen

and some helium. It sort of gradually gets more and more diluted. It cools down. But it's dark. There's no stars. It fades away after the brightness of the Big Bang. And you go through this period we call the Dark Ages, where the universe is dark. And then eventually, we think probably something like 500 million years later, the first stars are born because the dark matter, and I know we're not allowed to talk about dark matter on this particular episode, but the dark matter sort of clumps together and then sort of normal matter, if you like, falls into that. And so you get these sort of

dense spots where the first stars form. When the first stars form and they start to fuse hydrogen and helium, they light up the universe. We call that cosmic dawn. So you go from the Big Bang through the Dark Ages to cosmic dawn. And that period, although we know a lot about the Big Bang, we know very little. We haven't observed the Dark Ages and cosmic dawn. And that's what we're building a new telescope.

The international headquarters of it is here, actually, at Jodrell, the Square Kilometre Array, a big array of radio telescopes in South Africa and Australia. And one of its key science aims is to observe the cosmic dawn, to see the effects of the first stars lighting up the universe. That is so beautiful. I'd never heard that phrase until today. It's the first time.

So when did that become part of, you know, cosmic dawn? Again, the beauty which can replace so much mysticism. Just with that terminology alone, you go, that's a better narrative than my previous Odin-based one. But we do think now, is it widely accepted that stars form before galaxies? We do, yeah. The galaxies come after, which is a very counterintuitive idea. Yeah, but of course we haven't observed it.

So we have supercomputers we put in all the physics we think we understand so so obviously clearly we've heard we there's lots we don't but we we do we do already understand a lot we put that all in the computer we churn the computer through we make a model of a big chunk of the universe and we see what happens in the computer simulation and yeah that's what pops out these stars are formed these galaxies yn y symuladrwyr cyfrifiadol ac mae hynny'n cyfleu. Mae'r stair yn ffurfio, mae'r galegau'n sefydlu'n gyfres. Rydych chi'n creu'r ddwylyg ddwylyg, y gweb ysgol. Mae'n debyg os oes gennych chi bwbl bach a'ch bod yn edrych ar y ffwrm ac yn gweld y bwbl, y math o gyfranogolwyr rhwng y bwbl

a'r galegau a'r stair yn ffurfio gyda'r fwyaf o fwyau rhwng nhw. Gallwn weld hynny'n gyffredinol. Felly mae gennym y symuladrwyr ond dydyn ni ddim wedi cael y sylwadau o'r cyfnod honno. Ac wrth gwrs, ni ddim yn dweud yn unig that directly so we have the simulations but we haven't got the observations of that period and of course you know we shouldn't just believe theorists we should make observations and see what the universe is really like that it's a vast universe that we look out to i wanted to go back actually ben because you wrote a book recently on life in this vast cosmos it must be it must be the case there's life somewhere.

But if we talk about civilization, the question, I know Frank Drake, the astronomer, defines civilization as something capable of building a radio telescope. That's his definition. In the sense that at least you could communicate. So what was your feeling? What position did you come to on the likelihood of us making contact with these telescopes, seeing another civilization?

Well, I think a bit like you, I feel that microbial life, bacterial life, that seems to kickstart itself. If life on Earth is anything to go by, and finally it's all we do have to go by at the moment, if that's any guide, it seems like that happened pretty quickly on Earth. And it seems like that's almost a property, I mean, to quote you, your ancestors are rock. You know, it's quite possibly volcanic vents on the seafloor of the very early Earth that produced the first cells. It feels like that process, the harnessing of everyday chemical reactions into a life form happens almost in a continuum from as soon as you create a rocky planet with some sort of tectonic activity, you start to get that basic kind of life.

The real question, and it's very, very hard to answer, I think, with the limited amount of information we have, is the leap from these almost two different kinds of very simple life that started the archaea and the bacteria here on Earth, which then merged, it seems, in one single event from which every other complex organism then evolved. That only appears to have happened once. And so the question is, how rare is that event? This is, in principle, an answerable question, isn't it?

And SETI, using telescopes like the Lovell for SETI, was frowned upon for many years, whether it was seen as a fringe activity. Is it still, and do you do it here, and is it legitimate now? So SETI is the Search for Extraterrestrial Intelligence, often with radio telescopes. The reason you might say it might be frowned upon is because you could spend your whole career

using up all the time on radio telescopes like this one, searching for signals from aliens and never getting one because we have no idea if aliens exist, we have no idea if they're sending us messages, and so that's why, in a way, it's fr upon, because there's loads of other interesting stuff we could be doing with the telescopes. But actually, in fact it's now part of the key science aims of many telescopes. So we have done SETI with this telescope, we did the thing called Project Phoenix which we searched all the thousand nearby stars with a few telescopes around

the world including this one. We didn't pick anything up, otherwise we would have told you. But the square kilometre array, that's one of its science aims. It will do setting. So although it will do all the stuff at the same time as well, it's got this clever system of being able to look at multiple things at once. See, I want to ask you how putting together the images that you get from the signals. So, you know, that itself is not as, you know, that translation from the radio signals to the image of the objects that you're talking about. Yeah.

So, you know, in a way, you're seeing the invisible universe. So you're probably familiar with, like, thermal imaging. So infrared cameras that see at night. So you're seeing the infrared glow that we're all radiating now. ymddiriedol. Felly, mae pobl yn debyg, rydych chi'n debyg yn ymwybodol â ddifonu thermol. Felly, cameraau ffynhedol sy'n gweld yn y nos. Felly, rydych chi'n gweld y ffynhedol glwydro rydyn ni i gyd yn radio nawr. Felly, gallwch chi weld yn y nos gyda hynny. Mewn ffordd tebyg, rydych chi'n gweld y glwydro radio o'r sgai. Felly, mae'n ffordd gwahanol o blynyddoedd. Felly, mae'n un o'r ddwy ffyrdd eletro-magnetic o'r blynyddoedd gwahanol. Ond mae'n gweithio yn yr un ffordd ymhellach. Felly, gallech chi ddefnyddio telesgop radio fel'r un y tu ôl yma ac allwch chi ei sganio ar draws y sgai ac allwch chi exactly the same way. So you could use a radio telescope like the one behind us here, and you could scan it across the sky, and you could measure the brightness of the radio sky and build up a picture that way. Or in fact, what we do is we connect this telescope

to other ones across the country in a big network. We connect it across to other telescopes across the world. They join forces, and we create a telescope the size of the planet. They join forces and we create a telescope the size of the planet. Charlotte, how do you feel about the idea of what human reaction might be to... Because we think that we certainly, every time we've found not merely similar species, but even our own other humans, if we've considered ourselves superior to them, we have very often not treated people well. So the idea of sentient extraterrestrial creatures that may well even be superior to them, we have very often not treated people well. So the idea of sentient extraterrestrial creatures that may well even be superior to us,

how do you think human beings, that first announcement, do we end up with that kind of Orson Welles moment of panic during the broadcast of War of the Worlds? Yeah, yeah, definitely. I think everybody... People are pretty fearful on this planet right now, and I should imagine that if you throw that into the mix, then they might completely lose their minds entirely. I think it would be wonderful. yn ddifrifol ar y planed honno ac mi fyddwn i'n dychmygu os byddwch chi'n rhoi hynny i'r cymysg yna, efallai y byddant yn llwyddo eu meddwl yn gyffredinol. Rwy'n credu y byddai'n

wych. Fe wnes i ddarllen rhywbeth ddiddorol o'r Harvard. Roedd rhywun yn dweud ei fod yn meddwl bod y bywyd mwyaf amrywiol ar blynyddoedd arall y byddant yn cael ei ddysgu yn bywyd biologol oherwydd mae'n ddifrifol. Mae'r bywydau fwyaf yn fwyaf yn gallu ddysgu bywyd biologol. Yn wir, byddwch chi'n edrych ar roeddiadau mwy fel because there are far fewer planets which could sustain biological life that actually what you'd be looking at is far more like super intelligent robots, like AI, who could live in all different sorts of terrain, who would not, and the reason that they haven't contacted us is because they're so far advanced that they really don't care. They're totally disinterested in having a conversation.

So we're just like a sample on a slide from pond water. Yeah, but I quite like the idea of super intelligent robots, you know, just patrolling the skies. I think you've got your prog rock album waiting for you there, definitely. You said that you think people would panic, but it could be quite a unifying thing. I mean, it's probably a radio signal or something most likely, which means they're untouchable, as it were.

We're not going to be able to visit these things. But knowing there are other civilizations out there, do you not think that might be a unifying idea? I think it would be completely wonderful, but I think that so many people have watched so many disaster movies. I'm specifically thinking about Mars Attacks, which is one of my favourite films.

I think, you know, the idea of knowing that something else existed and then that tantalising thing of not necessarily being able to know anything more or contact or do anything would just be... I think it would drive people mad. Isn't there something... Bertrand Russell talked about the idea that what we almost need, even if it was a fictionalised version,

I think this was done in Outer Limits or Twilight Zone as well, which is the idea that just out there is an extraterrestrial species that may invade at any moment, and that might be the only thing that actually brings human beings together is because they think there's something else

that's going to try and get them. Yeah, you create a bigger enemy, essentially. Which is a bit sad in a way. Yeah, it's true. I'd hope we'd be able to come together without having to create an external enemy. It's funny, this festival's called The Blue Dot, isn't it? Which reminds you of that famous

Carl Sagan passage where it was sort of seeing ourselves as a planet suspended in this empty galaxy that sort of seeing ourselves as a planet suspended in this empty galaxy that sort of really made us reimagine ourselves as a species. I think when you see another, you know, when we see evidence of another living species out there in the further stretches of the galaxy, I think it I think it'd be a tremendously unifying thing for us for very positive reasons, because we really have to think about what our aims are, what we're here for, and I think

there's so much division in the world and in society at the moment, and I think we could really benefit from having some sort of protocol, having some kind of UN meeting, some subcommittee where we decide what we represent and what we would like to communicate to alien civilizations out there. And basically tell them we want to leave Europe. With these lines, I mean, this is, you mentioned it

and I said we brought it on with the show, the Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they can become the momentary masters of a fraction of a dot. And then it just said it has been said that astronomy is a humbling

and character building experience. There's perhaps no better demonstration of the folly of human conceits than this distant image of a tiny world. To me it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home

we've ever known. And that to me should be... If you gathered every, not just every human being should read this book and every politician if they even just read the introduction of this book when you do think that

the few people who've been able to leave this book and every politician, if they even just read the introduction of this book, when you do think that the few people who've been able to leave the planet Earth, Tim Peake and Chris Hadfield and Gene Cernan, and they have been the very few who've been able to see the whole of the planet Earth in their field of vision and the way that it has changed them, it's a fascinating thing. But we have a

final question. Yeah, we are coming towards the end. So the final question, you won't have known it, this structured discussion, it was about things that we don't know. Oh, yeah! The final question to everyone is if there's one thing about the universe

we don't know now that we could find out, what would it be? For me personally, it would be a quantum theory of gravity. How does gravity work at the quantum level? I'm close to wanting it to be aliens, but for me, no. It's a bit dull, sorry. But yeah, a working quantum theory of gravity. Tim.

OK, we're not allowed to talk about dark energy. No, you can. You can, Dan. I've loved watching your pain. Oh! Let me talk about dark energy! OK, so the thing is, the really embarrassing fact is that despite all the stuff we do know,

all the stuff that we're made of, that we see around us now, makes up about 5% of the mass energy density of the universe. So 5% of the universe is the only stuff we understand. So the rest of it is dark matter and dark energy. We have no idea what dark matter is

we've known about it since the 1930s it's stuff that has mass it has gravity but we don't know what it is we found this other thing back in 1998 we also didn't know what it was so we just called it after the thing we already didn't know what it was so we call it dark energy and this is the stuff that appears to be causing the expansion of the universe to accelerate and I think given that that's 95% of the whole blood universe I think We really ought to try and understand what that's the first Charlotte I Might sort of carry on a bit from that and this is this is complete like this is complete cod science But I would like to find some link between so Codd, ond hoffwn ddod o hyd i ryw fath o ffynniad rhwng y cwmpas a'r egni cwmpas, ac rwy'n

gweld hynny mewn ffordd tebyg i'r ffordd nad oes gennym unrhyw sylw o ran beth yw'r cywysedd, o'i gwahaniaeth â'r rhan fwyaf o'r rest o'n meddwl. Felly hoffwn ddod o hyd i ryw fath o ffynniad a chael fwy o ffynniad i ffyzic yn gyfan. what consciousness is and possibly make a bigger link to physics as a whole. Why not? You know, it's a theoretical question. This suddenly feels, because of these high stools, it does also feel like a bit of a blind date thing, where Brian's going to go, well, I'm going to go with number one, because I thought the quantum theory of gravity answered. So, Ben, are we alone?

That's what I want to know. Are we alone? That's what I want to know. Are we alone? You know, we could be right here, right now. There could be messages. There could be communication from alien civilizations that we're not even aware of. I find that just an amazing thought. And it's been said many times before,

but either possibility is incredible. I think most famously by Arthur C. Clarke, either we are alone or we're not, and either is absolutely mind-blowing. Well, we're going to bring it to a close with something we didn't even get around to talking about, which was the Golden Record. And, of course, now it will be a golden iPod or USB,

and that will all be required. But we were wondering what should be placed on the next golden record that will be sent on whatever might be the next Voyager. And Charlotte came up with an idea for what song she believed should be on that record. So please welcome to the singing microphone, I believe, and also joined by her writing partner, someone who performs with a great deal, Johnny, as well.

So this is Charlotte's belief of what we should place on the next Golden USB. All right. CHEERING Sometimes I lose myself in me I lose track of time And I can't see the wood for the trees You set them alight Building bridges as you go

Too weak to fight you And I've got my personal hell to deal with And you say Walk my path Wear my shoes Talk like that I'll be an angel And things can only get better, can only get better Now I've found you, you Things can only get better

Can only get better Now I've found you Ready? Things can only get better Can only get better Yeah I can Can only get better Now I've found you There we go Ladies and gentlemen, Charlotte Church

and Johnny Vax That was, uh, that was a bit like stars in your eyes, because it turned out not everyone knows the song as well as they imagine. Things are going to get better. Can I just say, I didn't know you were going to do that. No, we did keep that quite quiet. Thank you very much, Blue Dot. This is the first time we've done it in the open air, in a field. We have been very happy to have with us Paul Abel, Tim O'Brien, Ben Miller, Charlotte Church. That's the final show of this series.

We'll be back at Christmas. Thank you, Blue Dot, and goodbye. In the Infinite Monkey Cage Turned out nice again. In our new podcast, Nature Answers, rural stories from a changing planet, we are traveling with you to Uganda and Ghana

to meet the people on the front lines of climate change. We will share stories of how they are thriving using lessons learned from nature. And good news, it is working. Learn more by listening to Nature Answers wherever you get your podcasts. you