The past and future of exoplanet studies

Hello everyone and welcome to Space Cowboys, a BNR podcast brought to you by Yeah! Science, where we follow the modern explorers of our universe. My name is Thijs Roes and today my guest is Lucas Ellerbroek. Lucas and I met in New York through a mutual friend about six years ago, back when he was just getting started on his book Planet Hunters, in which he describes the history of the epic, I should say, hunt for exoplanets. Yeah. Nowadays, Lucas is the Institute Manager at the Anton Pannekoek Astronomy Department of the University of Amsterdam. And in our conversation today, we're going to explore how far we'll be able to peak in the coming years. Yeah, with all the new instruments coming out. And we just had a really wild exoplanet decade. And I'm really curious as to see after this golden decade, how this will be. Yeah, I think we'll see how this will develop. So we'll talk about oceans of methane, robots versus human exploration, and also about a drunk moose that fell off the stairs at the mansion of Danish astronomer Tycho Brahe in the 17th century. Yeah. Enjoy. So we're going to talk about life in the universe today. And a lot of your work has been about star formation and planet formation. True. As an astronomer. And you've come across all these exotic places in the universe. And you said something before the show that I thought was very funny, that you were very disappointed while watching Avengers Endgame. Yeah. You were disappointed in the science fiction planets in general, in movies. The lack of creativity in painting pictures of what other planets around other stars could look like. They all look like the Earth somehow. And Earth in itself is already quite diverse in terms of landscape. But I mean, they go to this planet, I forget the name, and it's very, meant to be very exotic, but there's just a staircase there. Just like a human staircase. Like, well, wouldn't that be something very different from what we see on Earth? They could have done more with it, you mean? Yeah, I don't know. What kind of planets could they have done? Oh, that's the point. I don't know. So maybe I'm just asking for things that aren't there. And maybe the whole point is that in that particular universe, everything came from the Earth. And so was created in image of the Earth. I don't know. Yeah, of course. But my point was what we see in nature, as far as we have seen other planets, which is something that's quite difficult in itself. We do see environments. We do see environments that are quite different from here and quite unimaginably different. While having the same base ingredients, you do create environments that are completely unbeknownst to us. So in that way, I think that maybe I haven't seen enough science fiction or read it, but there's a whole universe of creativity just lying there to be made. It's very often something that looks like Mars. Yeah, right. Avatar. Yeah. Something resembling the extreme environments that we see on the Earth are exaggerated on other planets. Yeah. And it might well be the case. But for instance, within our solar system, we know quite well about environments that are quite different from the Earth, and we can describe them in some detail. For example, Titan, Saturn's largest moon, is quite like the Earth in that it has an atmosphere. And the landscape, we put a lander on its surface. And we can describe it in a way that is very reminiscent of the Earth. You see lakes and mountains. But the lakes contain liquid methane, not water. Methane is a substance that only occurs in gaseous form on the Earth. But in Titan, because the atmosphere is so thick, methane becomes liquid, and it's very cold, so it becomes liquid. It's a pressure thing. It's a pressure and temperature thing. And in those environments, you get a chemistry which is similar to the chemistry we have on Earth. But with different ingredients. And it rains there as well? Yeah, you get oily methane rain. Oily methane rain. It's one of the few places in the solar system where there is an atmosphere, so you can actually smell there, and it would smell like gasoline. Like gasoline. Yeah. And if you would light a match, is there any oxygen to burn anything? I don't think so. Okay. No. Because, yeah, no. Okay, well, that's good. So you can at least take a swim in gas methane. Yeah. It'll be cold. It will be cold. You need a bodysuit. Yeah, yeah. And you can actually cool because there's an atmosphere that you can transfer heat to. Because in space, this is a, well, maybe I'm diverging too much. No, yeah. Please, please do. One of the nice pop quiz questions is, if you were floating around in space without a spacesuit, what would you die of first? Would it be exploding because of lack of pressure? Or lack of oxygen? Suffocating because of lack of oxygen? Or freezing? Okay, I'll go for freezing. It is lack of oxygen. Oh! Because there's no air in space. I mean, it's virtually a vacuum. So, yeah, it is cold, but there's no atoms to transfer your heat to. Okay. Yeah, there's no... And so what happens to these atoms? They just don't really cool down? You're very well isolated. Yeah. But you do cool, but very slowly. Yeah. And you suffocate earlier than that you freeze. Oh, wow. And in terms of exploding, yeah, there might be some oxygen left in your, or just air left in your lungs. So that may indeed... It will collapse. Yeah, but you suffocate earlier than that happens. Yeah, yeah. Okay. Yeah. So suffocation is... So, yeah. Yeah, if you don't get oxygen, you die pretty quickly. That's a very insightful thing also for the search of extraterrestrial life. Well, why? If there is no... Well, I mean... Oxygen is a very... For life on Earth is a very vital ingredient. And it's also very volatile. So it disappears quite quickly if you do nothing. That's very corrosive also, right? Yes. I once heard that it's kind of weird that life knew how to evolve, how to breathe oxygen. Yeah. Eventually, because in general, oxygen is way too reactive. Yeah, and the first forms of life are supposed to have been... They couldn't stand oxygen. They couldn't stand oxygen by itself. So, actually, oxygen was a toxin to the first forms of life. Yeah. Which had an anaerobic metabolism. What does that mean again? That means that anaerobic means no oxygen. And their biochem cycles were basically without oxygen, but rather they would live off methane. Okay. So there would be, again, a similar... Well, biochemistry, but with a replacement of ingredients. Yeah. So, actually, at some 2 billion years after the Earth... Formed? Formed. Right away from the start, it was already life. But about, I think, 2 billion years into it, there was what's called the oxygen catastrophe. So that basically, there was a lot of life forms emerging that created oxygen and that lived off oxygen. And they basically killed... Oxygen killed all the previous life forms. And I don't know. I mean, I'm not an expert. I'm not an expert, per se, in that field. So I don't know which country... Evolutionary geology. Yeah. And maybe nobody knows the answer because we can go back in time. But have we found oxygen on different planets in our solar system? No, not yet. Well, in our solar system, yes. Okay. There is some oxygen, for example, on, I think, was it Ganymede? Oh. It's a moon of Jupiter. It has a lot of oxygen in its atmosphere. Oh. But that oxygen was created by, likely, by photodissociation, it's called. So by decoupling water into oxygen and hydrogen. Aha, yeah. By radiation. Yeah. And, yeah, that's actually the same that happens in our atmosphere way up there. Because all the other oxygen is, of course, stored in a way in water. Yeah, exactly. Yeah. And if we talk about exoplanets... Have we been able to find... Do we know any of the... I mean, do we actually even know the composition of any of these exoplanets? Yes, we do. We have looked at atmosphere... When I say we, I just mean the royal we, you know? Yeah, the royal you astronomers. The royal, like, other people in my field. When I say we, I mean other people. Yes, exactly. When I... Yeah. Anyway, yeah. Yeah. We have detected gases in atmospheres of exoplanets. I mean, the other day there was a water vapor detected in an exoplanet, which is very good news. So we keep discovering all these familiar gases. But oxygen is a gas which has not been detected yet. And it would be kind of a holy grail. Oh, yeah. I think that's the next holy, well, stepping stone towards detecting life in the universe. Finding oxygen. Finding oxygen does not mean life. No. Yeah. We know... I mean, we've had the Earth without oxygen with life. Exactly. And it's not sad that if there's oxygen, it has to come from life. We just know that the evolution of oxygen on the Earth is kind of simultaneous with the evolution of life. But like you say, life has existed for which oxygen was toxic. Yeah. But anyway... That's something that always struck me when it comes to finding extraterrestrial life or finding... Exoplanets. Is that very often we're looking for something that... A situation as we know it now. Can you maybe talk about that a little bit? Why is it always like that? And should we be more open-minded or is that actually... You mean life as we know it? Yeah. If you say that oxygen could be a holy grail, then that might... Does that include bias? Is that bias or is it smart? It is biased. Or is it smart? Both. Okay. I mean, as long as we are aware... Aware of our biases. One of the research groups I describe in my book is Sarah Seegers. She's at MIT. Professor. And she... She studies atmospheres. Exactly. Of exoplanets. Exactly. Yeah. She did a lot of work on how you can detect exoplanet atmospheres. And she has thought about this topic called biosignature gases. So basically, she flipped the question. So she acknowledged the fact that we are basically... The only example of life that we have... Is here on Earth. And we... The first thing that we look for is life similar to Earth. But the whole universe might come up with something different than our life form. So she was basically asking the question, okay, so what is life? And what in... Can we make a very general definition of life? And what it needs and might use? And what kind of chemistry might underlie that? So she has come up with a short list of molecules. That might play a role within biochemical cycles that have the same kind of energy balances that our biochemistry has. And then she has also from... Well, she started with a long list, but from that she had to like scratch off a lot of things that you can create also with no life or just with geology. For example, methane is something that can be created by life, but it can also be created by volcanoes. Yeah. So... Detecting methane, which has happened, does not say there's life. So Seager was looking really for smoking guns. Yeah. And turns out that the list that she ended up with was very short. And aside from oxygen, there were only a couple of other gases, which are for various reasons, not really feasible to detect. So, yeah, that's actually why we come back to square one saying, well, if we would see oxygen and maybe also the combination of... Yeah. So if there's, for example, oxygen and methane, if you just leave them in a room, they cancel each other out. They react and they turn into different things. So if you see them simultaneously, you know that there's something out of equilibrium. Yeah. Something's doing that. Yes. Yeah. And that kind of things. And if you don't detect one example, but a hundred or maybe preferably a thousand, and out of those, 80% have this weird combination of chemicals that you wouldn't expect. Yeah. Yeah. Yeah. And if you don't expect in an equilibrium situation, then you might be after life. Mm-hmm. But that's a very indirect proof at best. Yeah. And I'm thinking, how far are we with actually finding the atmospheres of different planets? Good question. Yeah. We spoke to Lisa Kaltenegger from the Carl Sagan Institute. I think she was still in Heidelberg in your book. Yeah. When you talked to her. She was still in Germany. Yeah. She's now in Cornell, I think. Yeah. She's now at Cornell University. She's heading the Carl Sagan Institute. Right. Yeah. Looking for Earth 2.0. Yeah. Yeah. Yeah. And I think that she said that they're really waiting for the James Webb telescope to go up, which has been delayed a billion times already. Yeah. And over budget. Yeah. And over budget and everything. Yeah. Do you know, like, can we already measure these atmospheres in any other way? Limitedly. So, atmospheres have been measured. So, there's two things. You need the right glasses to do it. You need to look at the right colors of the light in which there are signatures from the right molecules. And that's why James Webb is interesting because those colors, those wavelengths that you need to look at are far infrared wavelengths. That's actually radiation that is also created by the Earth. So you really need to go into space to detect it because there's too much of it in our own atmosphere that will dilute your observations. Okay. That's why you need James Webb. And we just need to go into space to detect it. Yeah. And we simply do not have another observatory capable of that. That's good enough. That's good enough. Like James Webb. Yeah. Also, you need the right targets. So, we still are in dire need of new planets to be found to be very, I mean, we already have a lot. Yeah. But we need… Thousands. Yeah. Like more than 3,000. But we need planets on which we think life may have a chance. And those would be planets which are not too big. Because if they're too big, they're too gaseous. They're like Jupiter. You just plunge into it and you do not survive as life. So you need terrestrial planets. And you also need them to be on a distance from their star where it's in theory possible that temperature is right for molecules to survive. This is a very general description of what's usually called the habitable zone, which I object to that terminology. What? The habitable zone? Yeah. So it's way too… It's just suggesting that you can just go there with your rocking chair and just have a pina colada at the beach and it's very habitable. I mean, the only thing we know about those habitable zones is that they are at a distance where in theory you could have liquid water on the surface of the planet. But it all comes down to what kind of atmosphere the planet has. But anyway, you need the right places to look at. You need the right targets. Yeah. And you need the right sensitivity. Yeah. And that's where technology comes into play. Yeah. Yeah. Because we're looking for very small planets relatively close to their stars. If you would look at the Earth, if you would look at the Sun from a distance, you would barely see the Earth because the Sun is too close to it. To disentangle the light of the Sun from the light reflected by the Earth, yeah, you need a really, really sensitive telescope for that. And you need to be lucky to have a target reasonably close to the Sun so that you can actually… That helps because the closer the star is, the… To us. To us, yeah. Yeah. The closer the star is that we're looking at, the more you can basically resolve it. You can basically play this game of destroying the starlight in your image and just being… Looking at the light from the planet. Yeah. So we need to be lucky to find good targets. And then we need to get a telescope with the right sensitivity. And even the James Webb telescope, its scientific promise being enormous as it may be… Yeah. …that even that telescope will likely not be capable of detecting oxygen in an Earth-like planet. You're kidding. Well… I've been waiting all these years… Yeah. …for nothing. Well, I mean… You tell me now. …the reason that people don't say this is that the chance is not zero but we still need to be lucky to find a planet that is even eligible to look at. Yeah, yeah. And I'm not saying… I mean, there's… My colleagues already have list and list and list and even proposals that are approved of stars and planets to look at with James Webb. Yeah, yeah. That I will be sure to find very interesting results of. Yeah. But having this Holy Grail planet, the Earth, like a copy of the Earth around the Sun, yeah, even if you would find it, it's very hard to get the data out. I think it was… Maybe it was a Carl Sagan book, I think, where he once described… But I forgot the answer, so maybe I shouldn't have started. This is the story where he asked the question, if you would be looking from that planet, to us, when would you be able to figure out what life exists here and second, like how smart that life is, what it's doing. Yeah. Then I think he comes down to the fact that even if you're super close and you're looking at it, you see steel machines being infested by some tiny little creatures and then driving them all… Yeah. They drive all over the planet. Yeah. I don't know that particular title. It might have been also in Contact, his book and movie. Yeah. Contact, his book and movie, where he also talks about aliens detecting Earth through radio signals, which were basically broadcast of Hitler's speeches. Oh, yeah. Which were the first ones that were widely broadcast over air. Which would also mean four billion years of not sending out anything. Exactly. Exactly. And then life is suddenly sending out radio signals. Yeah. So without the radio signals, you wouldn't know until you're super close… Exactly. …what sort of life exists here. Exactly. So this search for extraterrestrial intelligence, the SETI project is very biased by itself and it knows it. I mean it's… Yeah. But yeah, that Sagan science is very interesting. He also has a paper in Nature in the 90s where he does this looking at Earth, what does Earth look like as a planet from space. And he also says, yeah, we can also detect these… Yeah. Yeah, indeed, radio signals from Earth, but they would also be diluted by Jupiter. So we can look at the landscape changing and the impact that it has, that life has on the landscape. So basically there's seasonal changes in the oxygen content in the atmosphere, which you can attribute to life. One thing which I find very neat is if you look at the dark side of the Earth, you see it's illuminated. By light. By light. Yeah. Which are all an effect of life. And if you look where those lights are and you look what those locations look like at the day side, you see it's all around water. So that already tells you a lot about life on Earth. That something… So it huddles around water. Yeah. Yeah. Exactly. Yeah. So… People live on the coast, they live near the end of rivers. Yeah. Yeah. Yeah. And it's interesting because we know what is causing it. But if you would see it without any knowledge of that, then it would be more difficult to unambiguously attribute that to life. Yeah. Yeah. So then… And it's interesting because if I just look at the past few years and also one of the times that we bumped into each other. I think we bumped into each other here in the Netherlands once, I think about four or five years ago. And then I thought we would… It was right before you wrote your book or… You wrote your book or you were writing your book because I was thinking about doing sort of the same thing. I was sort of interested in the same topic because I think it was also sort of a hype because of Kepler, I think. Yeah. Because all of these different planets were coming out. And then I heard you were already like working on it for a few years, which is fine because then I don't have to do the work. I did something else eventually. Yeah. It was funny. I remember that. I remember being a little bit afraid that you might make my idea. Yeah. Fortunately, I didn't. I didn't make your idea. I went to… I think instead I went to just Cornell to do videos about it for my channel. And I did a couple of stories for Motherboard in the end. Yeah. Yeah. And… But now the hype has sort of… It became a little bit more muted. Well, I don't know. And maybe it's coming again because of Tess? Yes. I mean, well, the way I see it is it's… Well, not surprisingly, but it is very persistent. Okay. It has emerged and it is still going. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. It is evolving. And also, the way that the public looks at it or the dish that the public gets served is sometimes… Yeah. Yeah. sometimes different from what the researchers are doing. And I, look, with planet discoveries, the first one was in 95. And then after, so that was the first planet. And then the next one was like, okay, so now it's a Jupiter planet. But then there was a planet that was smaller than Jupiter. That was a big news thing. And then there was a planet which was not one, but two planets around the star. And then there was Kepler, which detected 3,000 planets in multiple systems. And every time, and then we got this habitable zone things. So every time there's this milestone being acquired and to explain it to the public, like, okay, so why is this planet so important and new? And sometimes, I mean, planets get discovered like one a week on average, but not every planet is so interesting that it deserves like a front page article. And maybe we are a scientist over-promising a little bit and saying like, okay, so do you want to do this? Do you want to do this? This is the next step to life, right? Yeah. That's already being said in 95. We're really closer to discovering life on other planets. But if I'm honest, we are quite far from discovering life on other planets. Really? Yeah, well, I mean, we have all these new tools and we have James Webb and we have... We don't have it yet. Yeah, but we will have it. We will have the European Extremely Large Telescope. We will have all these facilities. So as long as we can reasonably keep up the technology with our imagination, then we will be very productive. But there might be a point where we, yeah, where we see, okay, well, if we want to detect these oxygen planets that are really small, we just need a telescope that costs 100 billion. Are we still that interested in the question, in the answer in the question? And are we really going to build this cathedral that will be finished in 100 years? So I don't know. I mean, I don't know how scalable... You can do it for the Sagrada Familia in Barcelona. Maybe we can do it for the telescope. I mean, astronomy... Astronomy in general, to put it in a bit broader context, astronomy in general in the last 50 years, last 100 years, has really soared. And it is also because we could make these jumps in sensitivity and we have these different glasses, so to speak. We have these different wavelength telescopes. We have optical telescope, infrared telescopes, ultraviolet telescopes, radio telescopes, all these different types of radiation we can look at simultaneously. And we have eyes in the sky on all of those wavelengths and they're complementary. And we can see that the combined power tells us so much. And then we can theorize as fast as we discover. And then the science flourishes. That's what happens with planets still. It's still happening with planets. We have still the ELT coming up. And during that era... The ELT is the Extremely Large Telescope? Sorry, the Extremely Large Telescope and James Webb. Okay, yeah. I mean, they will have like the observations. They will tell us about what the distant nature look like. Yeah. And scientists can also theorize about what that tells us about nature. Yeah. And as long as those two can go hand in hand to a reasonable extent, then the science will keep finding new things. But if one of the two dies out or hits a limit, then it becomes... Imagination or technology? Yes. And that's what, for example, has happened in high energy physics. Okay. Where, you know, CERN, the particle collider... Yeah. The Higgs boson that has been found. Yeah, that's found the Higgs boson. Yeah. I mean, particle physics in the 60s, when it emerged, was actually in the same stage as where exoplanets are now. So... Which is? There were... Well, which is where theory and observations went hand in hand. Right now they are. Yeah. So theorists like Feynman, Richard Feynman, predicted particles from their theories that the particles should exist. Simultaneously, the experimentalists worked on the machinery, that could design experiments that would collide particles. And voila, you would actually detect new particles from it. And so the theorists predicted and the experimentalists proved that they existed. And that made a lot of progress. And that resulted in what we call the standard model now. So the standard model is basically the ingredient list of all the matter in the universe. And... With the Higgs boson, that was kind of like the last piece of the puzzle of those particles. And... And so what happened in particle physics? Well, what happened is that... There are still a lot of unanswered questions. For example, we still do not know how gravity works. What is the particle that is actually related to gravity? Is there a particle related to gravity? So to answer that question, there's a lot of theories. But all those theories have one thing in common, that the experiments that one could design over that are either not possible, or we just not have the technology to... I once heard a particle accelerator the size of the solar system. Exactly. Things like that. Yeah, you just run into physical limits of what you are able to prove or disprove. And that means that theory runs wild. And I hope I'm not offending my theoretical physics colleagues. But... Theories run wild. And there's no way to measure them. There's no way to measure them. Yeah. So that's... I'm not saying theoretical physics is in a standstill, but it is in some sort of a crisis and a dearth of having new ideas. Okay. Yeah. Slowing into it. Yeah. And so you said maybe as scientists we run a risk of over promising things. Yeah. Because right now, they're really good in lockstep. The theory and the measuring of exoplanets just in this early phase of finding them and locating them and figuring out... Yeah. Yeah. Next step is characterizing them. And I think that there's a lot to be had from the characterization of planetary systems and just finding out how planets work. And right now it's super rough, right? We know, depending on the way they're being found, transit method or the wobble or whatever, you know a little bit like about their size, maybe their composition because of how it behaves. But we don't know that much. No. Or do we? Well, indeed. The basic parameters that you get from observations are indeed the size and the mass. If you get those two simultaneously, you can say something about the density. So you can say something about the material that they consist of. If you really want to see more, you're going to be interested in the surface. What's on the surface? Is there an atmosphere? You can also get that from a bit from those early observations. But pretty soon you need a spectrum. Spectrum meaning to... Actually disentangle the colors of the light reflected by the planet from the star. Yeah. So you have the star and you have the planet and the star shines on the planet and the planet reflects the light. Can you see that? Yeah. So that means that you need another step in sensitivity. You need a bigger telescope to do that. You need a James Webb, basically. Oh, yeah. Okay. But you can also do this with the Hubble Space Telescope, which is already in the air. And you can do that from the ground as well. And you can do it for the biggest planets or the closest. Yes, exactly. Something like that. Exactly. So that has been done for the gas giants, so to speak. So the Jupiter-like planets. Yeah. We have quite nicely described their atmospheres already. Yeah. But yeah, like you say, it is challenging. Yeah. But we can get to know a lot more in the next few years already. Yeah. And that in itself is already providing so much new science. And maybe that's undervalued in a way. We shouldn't stare ourselves blind on detecting that oxygen signature and hoping it is life. We should just appreciate the design. Yeah. And the discoveries that we can already make. It's just about collecting data right now, I guess. Yeah. And it is. And also knowing the right questions to ask. Okay. Because you can acquire a lot of data just basically blindly. But you do have limited resources. Yeah. So it is about finding the clever targets to look at. Yeah. To maybe point to Hubble. I'm trying to think. I think Hubble was launched before the first exoplanet was ever discovered. That's right. Yeah. That's insane. Yeah. And so right now it's sometimes being used for exoplanet research even though we didn't… And people didn't imagine that back then. That was very visionary. Yeah. We didn't know it existed. Hubble telescope we could do three episodes about. That's a very remarkable machine. Because Hubble's, in the end, it's a strength. Well, it is a fantastic telescope to begin with. But the fact that it has been serviced and upgraded by astronauts. Five times. Yeah. Up in the sky. Yeah. Up in the sky. That's unique. And that will not return very soon. Because James Webb is going to be at a location which is very difficult to access. Yeah. Behind the moon in a Lagrange point. Yeah. Exactly. It would be so epic though. It would be so epic to do a space mission out there. It's not being said that it is impossible. Yeah. And they might service it by robots. I don't know. Oh. But you should talk to other people about that. But that's what I heard. Yeah. But I think it's a very, very good thing. Yeah. But … Well, back to that thing about theory and imagination. You describe a couple of characters in your book … Yeah. … that are sort of the same. Very often you describe your characters as a couple. Yeah. That's true. Is it because you constantly wanted that distinction between these two? You do it with Kepler and Tycho, for example. Yeah. Yeah. Well, in that case, there were clearly two characters that symbolized these two sides of science. Okay. Tell me a little bit about that. So these two sides being theory and observations. Mm-hmm. And one of the points I try to make in the book is that theory and observations are ingredients for progress in science. And Kepler and Tycho was … The story was that there was this rich Danish aristocrat called Tycho who was kind of like a hobby astronomer. Mm-hmm. And he … This was before there were telescopes. But he had measurements. He had different instruments to determine precise locations of stars. So what he did was just look at planets and look at stars in the sky and just very detailedly measure where they were standing. Some sort of pinpoint … Yes, exactly. … device that he had. Yeah. Yeah. Just like a Google Maps of the sky he was making. That's what he was making. Yeah. And he, being an aristocrat, needed these people to look after him and he also needed like this retinue of … Yeah. Yeah. Interesting people to work with him. One of them was Kepler who was kind of his research assistant. Kepler was the research assistant of Johannes Kepler … Of Tycho. … the famous astronomer … Yeah. … was the research assistant of this … He worked … … gentleman Tycho. Yes, exactly. And he worked in Tycho's court and Kepler was … Tycho's court was kind of an insane place. Yes, exactly. There was this kind of this mansion in … on an island in Denmark called the Joranieborg, I think. It's like the Uranian temple. And yeah, the story goes that he had this crazy lifestyle, kind of like a great Gatsby lifestyle with a house dwarf that was pouring wine for the guests when they were there and there was like this … Shouting obscenities you wrote. Shouting … Yes, exactly. I compare him to Tyrion Lannister in this … in my book. Yeah. In Game of Thrones. Yeah. Yeah, exactly. And he had a moose that was drunk at one point and stumbled on the stairs. I mean, these are very precise anecdotes from the 17th century. I doubt their veracity, but they make for a good story. Exactly. The moose got too drunk. His house moose, his pet moose … Yeah. … got too drunk and fell down the stairs … That's it. … and died. Exactly. Yeah. Yeah. Poor moose. Exactly. So that … So that kind of describes how larger-than-life Tycho was and … He had an iron or copper … cut off in a fencing duel when he was young. Great story. Yes. So that was Tycho … So this gentleman gets Kepler as his research assistant … Exactly. … just to set the scene. Yeah. Yes, exactly. Kepler was this … apparently this introvert, very religious-minded scientist who was very … yeah … Mumbled. Mumbled a little. He mumbled a little and he was really good at … He was good at … He was good at … He was good at … He was good at … He was good at … He was good at … He was good at … He was good at interpreting observations. Okay. And he was good at mathematics and creating mathematical models of, in this case, the solar system. So this was when already Copernicus hypothesized that the sun was in the center of the … of the solar system and the earth revolved around the sun. Tycho was not so convinced that that was the case. He had his own model. And he basically hired Kepler to prove his model. Wow. Kepler made these measurements and concluded in the end … and this was way later … he concluded that actually Copernicus was right, but the orbits of the planets were not complete circles. They had to be ellipses. Yeah. And he concluded that based on getting the observations from Tycho. Tycho was really good at observing. And so he was … He was good at observing. He was good at observing. He was good at observing. He was good at observing. He was good at observing. He was good at observing. He was good at observing. And so he had observed Mars for a long time. And at some point Tycho, who had this extravagant lifestyle, apparently after a dinner party choked on his own food or booze or … I think his bladder exploded because he was too humble to go to the toilet. Yeah. You write that in a strange … in a maybe strange moment of humbleness, he didn't go to the bathroom long enough and then the bladder exploded. Yeah. That's the story. That's the story of Sorghagos. And of that, I mean, Kepler inherited his observations and analyzed them and made a big success of it. So … Yeah. Throwing away some of his earlier own conclusions. Exactly. And that was to Kepler's merit. He actually had his own idea about how the planets orbit the sun. But he had to relinquish that hypothesis because the data told him otherwise. And then he invented this model of ellipses which actually fit the data quite well. Yeah. A brave moment. I mean, a brave moment for him because you can also be a theorist that is too stuck to your old theories. Exactly. Yeah. And to this day, Kepler's laws are being used to describe planetary orbits. And that's why this successful Kepler telescope was named after Kepler. Yeah. Because you need his formula to actually get the size of the planets from the period of the orbits that you measure. Yeah. Well, this was in the 16th, 17th century. Yeah. When Tygo and Kepler were working together. I think you can only fast forward to only very recently, like say maybe the 90s. Yeah. It tends to find the same thing when you get to exoplanets where suddenly theory and observation are growing towards one another. Because before, when was the first exoplanet detected? 95. 95. Yeah. Before that, it was all just... It was all just a long, wild theory. It only existed in Star Wars. Yeah. Yeah. And people... The question simply wasn't considered interesting enough by scientists. Really? Yeah. Because this hypothesis, that's why I wrote the book. I just thought, all the ingredients for exoplanets theory were there in the 17th century. I mean, we knew that the sun was a star, that the earth revolves around the sun, that the earth is a planet, and all the other stars could have planets too. So aliens could exist. That's already what Christian Huygens, one of our famous Dutch scientists, hypothesized that other stars must have planets with people or with life on them. Yeah. 17th century. Yeah. Yeah. Talking about aliens. It was a science fiction novel that he wrote. Yeah. And my question was, why has it taken 300 years before we actually took the telescope to see them? Was it purely technology? Mm-hmm. Part of it was. But part of it was also that the question... Mm-hmm. ...in science fiction became kind of hijacked by science fiction. Mm-hmm. So these little green men got... Yeah, they're already in popular culture for hundreds of years. And that question of planets around other stars is something that, yeah, yeah, they're probably there. But we have more interesting questions in science to refer to, especially when technology actually became good enough to detect these planets. Yeah. When telescopes became developed in the beginning of the 20th century. Yeah. And then, you know, the first thing that came to mind was the fact that there was a lot of information about the universe. Mm-hmm. And then, you know, in the beginning of the 20th century, suddenly we had Einstein. We had Hubble. Einstein, who theorized about the cosmos. Hubble, that proved indeed that the cosmos looks a bit like Einstein predicted. And it's a lot bigger than we thought before. Yeah, exactly. It wasn't just the Milky Way. It was many Milky Ways. Exactly. So both astronomy and physics kind of went on these paths for their own. Mm-hmm. And astronomy became more like astrophysics. Mm-hmm. And astrophysics became more like the universe being the physics of stars. Yeah. So actually, the universe became a laboratory to study physics. And so when this first exoplanet was being detected, I mean, this was literally when the X-Files was still on. Yes, exactly. On TV. 95, yeah. Yeah. Super popular show about aliens being real but secretly hidden from us. Yeah. And so one man is, or multiple people actually, are trying to find a true answer to the fact that… Yeah. …that there are planets outside of our solar system. Yeah. What happened? So just to continue from the beginning of the 20th century, we had this emergence of basically astrophysics and physics. We had this particle physics revolution and everything and everything. And people that still said, yeah, aliens were kind of revoked, like, yeah, okay, you just go back to your science fiction and let me do the physics. And then the moon landing happened. And basically space got back into popular culture. Yeah. And of that moon landing, a lot of people got inspired to still… People like Carl Sagan actually got inspired to dare to ask that question, are we alone and how could we prove it? Yeah. And so basically people that worked on the Apollo mission, and one of them that I interviewed for my book is Bill Beruki, kind of got… Yeah, put his teeth into that question and thought of a way that we could actually look at the sky. Yeah. And discover planets. And he is the one who made what eventually became the Kepler Space Telescope that discovered all those planets. And his is kind of at the center of my book as a… Yeah, the hero of my book, I consider him. Because he went really against the grain and really had these… was considered to be like a crazy crackpot. Crazy crackpot from the beginning, right? Yeah. Yeah. Yeah. Yeah. Yeah. He was on a little team that was on cloud nine. He was learning and discovering little things and then got… In the meantime somebody else discovered the planet. And that kind of… Who did that? That was Michel Maillard. It was a Swiss, Michel Maillard and Didier Coelho, Swiss astronomers using a telescope in France. Basically they were looking for… Well, something slightly different from a planet. So they were looking for what's called brown dwarfs, which are actually very small stars, which are basalt班. people considered planets and there there were more brown dwarfs were more safe to look at from a political point of view so you wouldn't get called crazy by your colleagues if you would say i'm looking for brown dwarfs and they would say oh okay that's interesting if you would say i would look for planets then it would like oh man et get out of here oh wow so but so they uh were um actually well uh they found the first planet around another star a very big jupiter like thing because it was wobble the star was wobbling exactly yeah but uh the reason that they were able to find it was that this planet was very close to its star so basically it is like jupiter but way within the orbit of mercury um so it orbited not in 12 years like jupiter does but in four days four days yeah so but they observed for a couple of weeks so they observed a few years on that planet already within those couple of weeks and that's why but nobody i mean people instantly believed them but they were all really taken by surprise because nobody thought that a kind of planet like that would exist because we found it logical that within our solar system the small planets are close to the sun and large planets are outside why because planets form together with their star out of the same birth cloud that the star also forms out of and far from the star you have these uh colder uh materials and ices and they can easily form larger planets while closer to the star you have very little material and every every all the light material is being sucked up by the star itself uh or or disrupted or just or just just um um ablated so and that's because of explosions or whatever it's not just because of radiation it's just heated by the sun and just just blown away yeah so um we're so glad we can be so glad that we're here oh yeah that's very true that you can listen to this but this is but this is a riddle that still baffles everybody we still don't know how that actually works no but this particular jupiter like planet that's called a hot jupiter yeah um has likely formed further away from its star but ever since migrated inwards oh okay and that can happen if there's an old solar system or well old enough that this dynamical thing can have happened that there were multiple planets that kind of ping-ponged each other and so the fact that this planet is so close to its star now means that another planet got kicked out yeah then you say they all believed him uh because they could easily check it exactly if it is a they could look at the same star they could check the same data they could yeah just and they could think of a lot of things that it could also be and so there's still this wobble that you think about that you talk about can be caused by other things that have to do with the star itself and not with the planet so it still took a couple of years for people to really be convinced but five years later somebody else that i also interviewed for my book dave charbonneau and tim brown they um discovered a planet a different planet through an entirely different method but in the nem mixture it's a pretty broad method inЖ it it was really good i did a lot of research and there was a lot of people who got uh LIKE I lot of people who care because every one of them asked me how would we know so there was a lot you know you've seen that trs and how many things have you observed that pad기는 uh and decides that a planet is wrapped around the star to look at it whose rather than what is going to matter in terms of mass Ugusa Ebola and then how is it not to look up to know any other planets out there in terms of deducing these others you have two different methods by which you can detect a planet and if you also apply those two same methods on the same planet and still get the same result then that really is convincing yeah it's a confirmation of the yeah of the thing and eventually that's also what kepler used exactly that method can be easily applied to a lot of stars simultaneously yeah why is that because that's eventually so kepler comes a few years later uh the kepler telescope yeah and um it can do it can observe thousands of stars yes all at the same time yeah how does it work and how is it possible it's in theory easy because of and by the way bill barucki uh came up with this idea yes okay well actually uh he also built it off a paper that somebody else wrote who he credited but um uh so this method um is very simple because all you need to do is monitor how bright a star is and that's something that we know how to do for hundreds of years already oh nice he just had this uh tool called a ccd charge coupling device that we all know on our iphones is widely used everywhere in society back then in the 70s when he started thinking about this it was still very revolutionary very novelty yeah but because of this digital camera basically he could uh easily take photos of starry skies and very accurately measure their brightness digitally yeah, yeah, yeah, super easy yeah but yeah we say now super easy but I understand that part yeah back then it was revolutionary in the 90s when was the first the consumer digital cameras weren't until the 2000s yeah yeah so this yeah so barucki started his quest in the 80s and ccds had been around since the 70s I think but very basic yeah low resolution yeah yeah but yeah so for him it was easy he just needed to go to space because I mean he didn't have a camera he just needed to go to space because I mean he didn't have a camera he just needed to go to space because I mean he didn't personally but the telescope needed to go into space because in space you have basically no absorption from the atmosphere so you you see the stars way more clearly you have no distortion and he needed to pick a field of stars to look at yeah and just pick out the stars that behaved well so that were not too variable of themselves and were a bit like the sun so yeah but then still he could monitor the stars and he could monitor the stars and he could monitor the stars and it makes him a lived engineer because he wanted to but because on space he could it's impossible it makes him a lived engineer because he wanted to but because on space he could it's impossible but because on space he could it's impossibleắtt they thought they could not and then with this method transit method you can only detect planets 23 world let's then with this method transit method you can only detect planets that transit in front of their star that transit in front of their star that at the right angle exactly yeah and the that are just at the right angle exactly yeah and the planets don't care atts don't care that we are looking at them in our line of sceze yeah so there's only a percentage don't care that we are looking at them in our line of of the stars that will have planets that the stars that will have planets that theoretically have transits yeah so you could so you could just throw those away just throw those away But still, he was able to confirm more than 3,000 planets. So if you do the calculations, you can interpret that. Basically, the one-liner that Kepler discovered is that every star has an average at least one planet. At least. Yeah. A minimum. So basically, planets are a byproduct of star formation, period. Yeah, exactly. There's a better one. I think there's more planets than stars in the universe. There's more planets than stars. And it's so insane that, of course, we didn't get this in high school because we didn't know. Exactly, yeah. So now, literally, the high school texts are being rewritten. So that's why it's an exciting time. Yeah. And you think it will remain exciting? I mean, if we go back to what you said, like let scientists not overpromise too much. Alan Stofan, the former head scientist of NASA, said, we know. How? We know where to look for extraterrestrial life. We know where to look. And she said, I'm going to go out on a limb here and say we're going to find it within the next 20 to 50 years or so. Because the technology is coming, she said. Yeah. How do you feel about this? Yes. I think she's not too wildly overpromising, but I think the way that we... We will detect life eventually. We cannot really predict. And I think amazing things are going to be found in the next 15 to 50 years or whatever she said, 15 to 20. Something like that? Yeah. She said it already a couple of years ago. Okay, yeah. Yeah, I mean, I like being optimistic, but I think we should just be honest of what it is that we know that we can find. And I think that we will learn a lot about planets in the next 15 to 20 years. Yeah. And that we will detect a lot of planet atmospheres and we will find interesting stuff in there. Whether it points to life and whether we can unambiguously say it is life, I don't know. Yeah. But yeah, I think there's no reason to stop what we're doing. Yeah. Well, I'm glad to hear that. Please continue. I had to think about a hostel I was in recently with a bunch of... I was by far the oldest. They were all 20. And at a certain point, we were talking about extraterrestrial life and a large part of the group thought, without any sort of hesitation, that it was already settled and that it was already found. And like, huh, what? Have we not found extraterrestrial life yet? No, really? I was like, no, no, no, we didn't. Imagine the disappointment if they... The lack of interest some people will show when we finally find it because people think that we already found it. Yeah, well, that goes a bit too far. But... But it is true that even... Outside the scientific community. No, but inside the scientific community, a lot of astronomers that you ask, do you think there's life in the universe other than on Earth? 99 out of 100 will say yeah. Yeah. Yeah, a lot of people are already suspected. Will we find it? And how will we find it? You will have a conversation about that because probably most of the life in the universe, like most of life on Earth, is like simple or undetectable or does not build radio telescopes or spaceships or things that are easily detected by us. Yeah. But they're just bacteria. And monocular organisms. Yeah. Yeah. And they would have to satisfy us. And a lot of people don't even know that the... Maybe the older listener will know, but the past century very often, when it comes to exploration, was more finding out that there was nothing there instead of finding out what was there. It wasn't until more recently, I think, that we got to know the... Yeah. Yeah. I mean, when the first Mars missions went up, like there was a collective like, what the hell? There's nothing there. Yeah, right. Yeah. And the moon was the same in a way. Yeah. I mean, there was nothing of economic value there. Yeah. And that's, I think, sometimes that space flight, how that will evolve, I don't know. I don't know if there's going to be something useful being we were going to be able to take from space that will actually create economic value here on Earth. In the long end? In the long end. In the long end. In the long end. In the long end. In the long end. In the long end. In the short or what do you mean? In the short, in the, in the hundred years end. Okay. In the following century. It will just be a scientific undertaking or something for fun. Either scientific or touristic. Touristic. Touristic. And like asteroid mining, I have heard some really interesting visions of asteroid mining and how it is something more than just taking platinum out of an asteroid, but just using it to build an infrastructure in space. And I appreciate that thought, but still, I don't know. It's, yeah, I don't know how direct the value will be for us on Earth and how we should approach it as humanity to be very greedy and just take everything like it is ours in space. Do you have any thoughts about an alternative vision then? What do you mean? About space flight? Like if you're saying like, I don't know, I'm having second thoughts about, Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. I guess, not robots, right? You're fine with scientific robots. Yes. No, I think we should keep doing science in space and find efficient ways of getting to know as much as we want. But just using it for economic value, you're against? No, no, no. I'm also not opposed to having tourism in space. I just think we should think about the impact that we have on our own Earth and habitat. And I mean, if we have a thousand rockets flying every week, we do need to come up with some way to do that. with some cleaner form of launching them. And also, if we want to send colonies to the moon or to Mars, we have to think about what's needed to sustain them. I mean, all the resources that we need are basically here on Earth, unless we find a way of using resources that are in space. And still then, do you really want to go to Mars? I don't. Maybe. If it's convenient and if I have cold pina coladas. Yeah, well, that's the thing. There's no Starbucks yet. Yeah, there's no Starbucks yet. Yeah, there's no Wi-Fi. No. And it's going to be terribly slow. Like, there's going to be a whole bunch of waiting time. I think, yeah. So, I don't know. I think people will be on Mars at some point next 100 years, without a doubt. Yeah. Even though in the last 50 years, every year there has been, on average, one new planet. Yeah. And there's been a serious proposal to go to Mars within 10 years. Elon Musk has said, we'll be on Mars within 10 years. George Bush said, we will be on Mars in 10 years. I mean, 30 years back, Nixon said, we... I mean, everybody said, we will be on Mars in 10 years. And to this day, they still say so. It becomes a bit unbelievable. Yeah. But you're also thinking maybe, like, what's the... If it's cost so many resources, what is the actual value? Well, the value is... You're not sending a human there. The value is prestige. Okay. The value is that... Inspiration. Inspiration. It's a target. It's a very concrete target. It's very similar to what Kennedy promised with the moon. Yeah. If a Chinese man or woman will be on the moon, then America might stir and say, okay, now we're going to Mars. I don't know. It's all politically... Political prestige. But also, you get a new saying. Like, right now, the saying is, why can't we fix this? We've gone to the moon. We should be able to do dot, dot, dot. Yeah. We can replace the word moon with Mars and inspire a whole new generation. Oh, yeah. I think there's economic value in that sentence. Sure. Well, I'm quite excited about the value of robots. Like, for instance... Yeah. This year, a new mission from NASA was approved called Dragonfly, if you heard about that. No. It's going to be a drone on Titan. Oh, yeah. I heard about that. Yeah. Okay. It's going to be... A drone on Titan. A drone on Titan. Titan Saturn's moon, which is the only place where you can actually fly a drone because it has an atmosphere. Of course. And Titan, well, it's like we talked about. It's a very interesting place. It's going to teach us a lot about how planets emerge. So, I think the landing of Dragonfly on Titan in, I think, about 20 years' time or something, that's going to be the new moon landing for the new generation. Yeah. I mean... I mean, the footage is going to be incredible. Yeah. If you can fly over Titan in 4K video. Yes. Yeah. That would be amazing. That's insane. Yeah, that's insane. So, that kind of technology... Sorry, could we do this at Venus as well? Huh. Yeah. Good question. Yes. But you wouldn't survive for too long. Ah, yeah. The Russians have. I mean, they have sent like four or five landers to Venus and they... Yeah, there's some pictures that they took. There's some pictures. Yeah. Yeah, yeah. It's awesome. They didn't survive for long. No. The atmosphere of Venus itself, if you stay within the atmosphere, apparently it is quite... It's quite nice, the environment. What do you mean? It's like the temperature is quite agreeable and you can... And there's... The pressure is okay. So, you can just... Well, you can just free float there, but... Uh-huh. Actually, I think... So, what's the problem? Well, just urgency of going there. Lots of urgency. You're saying that Venus would be comfortable? Is that what you're saying? Yeah, but it's the sky. Oh, the sky. The high sky. The high sky. So, in theory, I haven't really looked into this, but if you would build a space station around Venus... In low Venus orbit, you might be able to survive there. Oh, yeah. But, yeah. To go outside. Yeah, but then... Sit on the balcony around Venus. Yeah, the only thing that you have is weightlessness and that you can also acquire here on Earth, around the Earth. Yeah, exactly. Exactly. Okay. So, I also saw a bunch of Boston Dynamics robots yesterday, dancing, jumping, twirling. This was insane. I was like, we can maybe send those to Mars. Just run around. Like, we'll have humanoid robots running around. Yeah. Yeah. Pretty much... Just for us to look at as entertainment. Pretty cool. Yes. And have... Yeah. Do gladiator fights. Like... Like robot wars on Mars. Like robot wars on Mars. That's a good show. Sounds a bit like the biker mice from Mars. Yes. But I would watch that. Yeah. I would watch it too. And then, yeah. Then science becomes entertainment. And in a way... So, there's your economic value. Yeah. Robot wars on Mars. It is true that those things might become important enough to people that they will spend money on it. Yeah. Yeah. Who knows? I mean, there's been documentaries about Antarctica, I guess. Yeah. Yeah. So, you're saying Titan is where we're going. We'll probably go to Enceladus. We'll probably go to Europa. Yeah. That would be exciting. Going to these exoplanets and figuring out how exotic they are. Is that a reality at all? It's very far flung. We would need either generation spaceships of people that... Just, yeah, hibernate and multiply on the spaceship or become bionic so that they can survive. Become like androids that can survive for a long time. Yeah. So, then it becomes instantly deep future science fiction. Yeah. Because physically the distances are very long and we cannot go faster than light. So, to go to the closest exoplanet is... If you have the speed of light, it's four years. So, if you get like... 10% the speed of light, it's 40 years. And then you need to break. That's just as difficult as launching. You need as much energy to launch as it is to break. Otherwise, you just shoot past it. Yeah, just shoot past it to take one selfie and then you're done. And you can't send it back. You can't come back. So, yeah, there's physical limits. You asked about the prospects of finding life. I think the opportunity to find life, the chance that we... The likelihood that we would find life is... That we would find it in the solar system, within the solar system. In one of those places that you mentioned, like Europa, Enceladus, possibly even Titan, but that would be very exotic life forms. Mars. Mars, perhaps. I don't think there's much life on Mars anymore. But Enceladus might have habitats that are very similar to early life on Earth. Yeah. And we know that there's geysers, as we speak, just blowing tons and tons of liquid water into the sky there. Yeah. From under the ice crust where there is an ocean and that's being heated from inside. So you have this environment that can sustain a biotope. So if we would find a way of going there and drilling through the surface and just ladling out a spoon of water and putting it under the microscope and looking at them, wriggling Enceladus microbe, that would be convincing and even more convincing than a couple of pixels in your telescope telling you there's... I think there's oxygen somewhere on an exoplanet. Yeah, definitely. I think Europa Clipper is not doing this, but it's at least exploring how to do this. Exactly. So, yeah, this would need another couple of generations of spacecraft. Oh, man. It's a long waiting chain. Yeah, it's a super... Everything in astronomy takes so long. Space missions are like cathedrals. They are built by generation one and then followed up by generation two or three. And then, yeah, then the end users are preceded by generations of scientists. that never got to see their their life's work yeah that's noble noble well yeah when it comes to your life's work let's talk about your last work are you working on a new book yeah I am okay so what are you focusing on my next book will be about the history of spaceflight and I've been working on it for some years now I hoped to have I had hoped to have it published this year because of the Apollo anniversary but yeah basically I interviewed a lot of people who worked in spaceflight in different generations starting starting well I started the book in the beginning of the 20th century and those people are not alive anymore but first rockets first rockets yeah and then basically there's three branches of rocketry in the US are the states and in Europe and I basically describe a bit against the historical background of the development of those Rockets I just interview people and what drives them to do what they do and I have a focus on science again I interviewed for instance Nancy Roman who is uh who was she passed away since uh who was the first NASA chief of science so in 57 she was set on a mission she's in the she was an astronomer but also an engineer and she kind of recruited astronomers to become enthusiastic to send telescopes into space and at that time people were not enthusiastic about that at all because they thought yeah that's just too expensive and we were quite happy with our telescopes on the ground so yeah I talked to her about what did it take to convince people to go to space for science yeah and then I talked to people who worked on the Apollo project that uh an engineer that designed the the mirror that is still on the Moon to this day oh yeah nice produced into like ranging experiments that the one that the distance the one yeah you can shoot a laser at it and see that it's there yeah I interviewed a space tourist Richard garriott nice he doesn't like to be called a space tourist so if you're listening Richard sorry private space Explorer a private splace yeah space Explorer but yeah he was explored a little bit of space yeah he paid to be on uh uh yeah I got give cake because unfortunately there was He paid to be on a mission to the International Space Station. Nice. And he also is like a space entrepreneur and a visionary for the future of spaceflight. So he is an interesting character to encounter. So yeah, it's kind of like a kaleidoscope book about what drives people to space. And where to go from here, maybe. Yeah, exactly. Because the options are endless. But like you're saying, the resources are immense. And the resulting value is unknown. Yeah, it's in a very pre-pre-pre phase. A lot of those business plans are now exploratory. So they're in a very early stage, I think. But will the 20s? Like we're nearing the end of this year, which means we're also nearing the end of this decade. Will the 20s be in? This was sort of like the decade of SpaceX, of course. Many of the exoplanet finds, the gravitational waves. When it comes to space exploration and finding life, what will the 20s bring? It will bring a lot of internationalization, more international presence in space. A lot of countries setting up their own satellite system. It becomes a decade that we really need to address things like space debris and space junk. And the space force. Cleaning up. After ourselves. Yes, exactly. And this space force that America is putting up. It sounds like a joke, but I think those things are good things to think about. Like this is actually our backyard. And how do we manage it? So I hope that some policies will emerge. In terms of exploration, there's a lot of missions that are planned. Going to Mars, but also to the moon. Of course, the states are again talking about putting people on the moon. I have yet to see if that's going to happen. But at some point, it will probably happen. I expect a lot of China because they tend to do things under the radar. And they don't overpromise. They just do and tell afterwards. So we cannot speculate as much. No. And I think it's exciting also to observe the dynamic between China and the rest of the world. And how China really wants to be, I think, considered a main player. Yeah. And they already are. They want the red planets. Yeah. Well, that will be. Yeah. And I think when it becomes political and when it becomes like a prestige race, then things might move faster than I project right now. Yeah, of course. And science, as far as science goes, I find it tremendously important to do good science and to get to know more. That has always delivered progress to us. But I also appreciate that science needs to also piggyback on big projects when they have to do it. And I think that's a great opportunity. Yeah. I hope. Science will also piggyback on the egos of the people that lead these countries. Exactly. Yeah, yeah, yeah. No, that's true. And that is not. We think maybe that it's the task of the government to do science, to fund science. But if you look at history, that has not always been the case. All those big observatories that are in the States that it started with are all built by people like Carnegie and big tycoons. You're kidding. As prestige projects. And they were privately funding. Just like. Just like Kepler and Tyco. Yeah. Just like Kepler and Tyco. And Elon Musk himself. Yeah. Yeah. Yeah. So it will be interesting to observe what will happen there. Yeah. Maybe. Could be government, could be private. Yeah. And then you have to think about, okay, so what is the ideology behind it? Are we just in it for the money? Or do we really want to discover more without requiring some return on investment? But there is a return on investment, of course. Like there. There are solar panels. Sure. There's pocket watches. There's this endless list. Yeah. That's true. But those have always been spinoffs. Yeah. Those have always been not the prime. Yeah. Not the prime target. The prime target, I think, still is signaling prestige, even for people like Elon Musk and Jeff Bezos. As much of a messiah they are considered by a lot of people in the end, I think for them, it's also that they're about business. And this is, I haven't looked at their books, but I don't think that space right now could be a really profitable business for them because NASA seems to be the biggest customer. Yeah. No, I think they do it because they're excited. They're almost boys who like to play with toys. Yeah, exactly. And for the betterment of all of us. And SpaceX is kind of like the prime supplier of spacecraft to NASA now. Yeah. And he has positioned himself very well. Yeah. And the big, I was watching the, this National Geographic documentary about the Falcon Heavy launch from a couple of years ago. And I was so amazed that it's only the launch of a rocket that already inspired so many people. Like it didn't find anything. It was just a weird thing. It was just, people were already excited that something was happening. And the landing of a rocket. Yeah. To have new innovation in space is very exciting to see. Yeah. And I find that very exciting to observe. Yeah. And I was also as amazed as everybody was to see those two rockets landing again. Yeah. It was really, wow, how can you pull that off? Yeah, exactly. That's so awesome. Yeah. And then, yeah, I'll just indulge all the egotistic things about it. I just think it's cool. Yeah, exactly. Exactly. So we'll see when your new book comes out. Yeah. And I think it's going to be a great book. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. But I think it's going to be a great book when it comes out. Yeah. But when it's out, please do come back. Yeah. In the meantime, you might enjoy my columns, my monthly column in the National Geographic Magazine in the Netherlands, where I have explored the solar system this year and next year I don't know where I'm going to. Ooh. Go outside the solar system. I might. Go outside the Milky Way. I might just do that. The exo-galaxies. Exactly. That would be a good one. Hey, Lucas, thank you so much for coming. Thank you. Very good to talk to you. And, yeah, talk to you later. And, yeah, thank you, Lucas. And yeah, talk to you later. And anybody listening, thank you so much for listening too. See you in two weeks. And until then, yeah, you can listen back to older episodes on the side of BNR or YesScience. Thank you so much, everyone. Thank you, Likas. Thank you. Bye.