So Matt, after that conversation, I'm ready for life to be discovered on exoplanets like tomorrow. I mean, I'm gonna need lunch first and then I think we're good to go, right? I'm excited. I feed you and then we'll learn about life to universe. Just a salad. We've been learning a lot about methane and stuff and I don't want anything too big. Okay, all right. Me too. Looking forward to this, life in the universe, finally with the methods, tools and tactics to figure it out.
And the James Webb telescope ending its hand coming up on StarTalk. Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. You'll be the grass-dice in here, your personal astrophysicist. I got with me as today's co-host, Matt Kirshin. Hey! I know. I know it's been so long since I saw you not through a screen. Yeah, like Israel, you can put posted notes on my actual face rather than just covering it on the screen.
No, no, that's what I do. I imagine. Welcome to town. Welcome to my office. It's lovely to be back. At the Hayden Planetarium. Yeah. I'm in the American Museum of Natural History. I mean, that's always exciting. It's fun to come to work. I hope it doesn't ever get all the time. I've never walked through the Natural History Museum to get to work. It never gets old when I pass little children seeing exhibits for the first time.
And I just remember when I was a kid. The or with that same experience. Yeah, the natural one. I mean, it's just... What's if he comes through at night? Yeah. Don't tell anybody. But all the animals come to life. It'll tell if he comes through at night. It'll tell if he comes through at night. I've heard the room. It's so important. It's really true. So today is going to be a cosmic queries. Great. And it's on, I think everybody's favorite subject.
The search for life in the universe. Now, most people just talk about it. But some people have invested research time trying to figure this out. Some people have actual expertise. What? I mean, that's what I'm actually saying here. Yeah. Well, then people like me just, you know, looking up at night and going, ah, it's going to be something, right? So I have with me Lisa Koutenniger. Did I say their name correctly? Kouten, Koutenniger.
Perfect. And it's so much fun to be here. And Neil, I have to tell you, even so it's the small kids that do the wonder when I walk through those doors. I'm back as being the small kid. You're kidding me. I'm just like, you can again. And I do want to know if at night the dinosaurs come alive because I'm here. We're just going to record until night because I want to leave. You don't want to leave. You don't want to leave. No, no way. So you, I have your brilliant background here.
First, you're an astrophysicist. But more importantly, you're an astrobiologist. So there's a whole bio side of you. And any biology I know, it's like, I have to pick it up on the side. But here is centerline with you. And your associate professor of astronomy at Cornell University. Who else was at Cornell? Somebody else? I don't know. Is there anyone? Brian's with Fagan. Is a Reagan. Oh, let me just cut it. Just someone involved in like, someone communication as well as, as well as research.
Wait, you know, there are books and, uh, there's this cool office on the third floor where Mrs. Carlton and her sitting right now, but it was the office that rhymed with Fagan. Oh, yeah. So it's who got Carl Sagan's office. There's an answer to that. Me, me, me, me. Wow. So I was, no pressure. I was in that office 50 years ago. Wow. This is not a 49 years ago. I was in that office. You know what? If you come back and being in that office, just think about what's going to happen then.
Oh. Oh. What kind of personal. Well, you mean, so what you have to do is get your office set so that we can reprise what he did. Okay. I'm in his office and he reached back. Did a no look reach behind him. No look reach pulled out a book that was one of the books he wrote. And then handed it to me, signed it to me. So you're going to have all the books that you wrote on that shelf. And then my shelf, so like all hickory, like I have like books piled.
So I'm going to just pull one and all things going to come to our city. Yeah, I feel like if I tried that, I'd somehow pull the book shelf onto me. You are director of the Carl Sagan Institute. Absolutely. And like I said, the answer to the question who got Carl Sagan's office and your research interest or you model habitable worlds. And so the great thing right now is we know of more than 5,600 worlds around other stars, other sons, if you want, you know, of course their name is not son.
But it's cool when you look up and you know that around every fifth one, there's a planet that's at the right distance and not to hot and not to cold. And a rock so small enough. And so it could potentially be a habitat as you said. And so we live in this time where with the James Webb Space Telescope, big telescope we put into space. For the first time we can catch enough light to figure it out. So why does the light tell you that there might be life? So the light is a cosmic traveler.
And the great thing about it is it's actually encoded information in it. That's how astronomers know how the universe works. Yes, we don't know anything without that, right? That's very true. If it's dark. You can't go there. You can't put it in a petri dish. Even so I do have to say the engineer should do a bit more work, right? I've seen this on Star Trek. I'm not worth it. I can do it. Now she wants them to go to the stars as well. You heard it here first. Engineers, you're all lazy.
Every engineer. I'm just saying abundant. The other stuff all pulled together and make me an enterprise, right? I would like to go to the other three firms. Okay. Do you want to upset this flying scientist? I can't satisfy it at all. But you know what the thing is, like I'm even doing the blinky eyes. If somebody gets me a Starship Enterprise, I will do that. I can't do that. Okay. That's what it takes. All right. So in the light, what's encoded there that is of value to you?
So basically, when you have light, what we do is astronomers is called spectroscopy, we split up in its colors, and we figure out if all the energy gets to us, or if some of the energy hit the molecule or atom before it got to me, and that's even so I can set foot. I cannot set foot on these planets yet. I can actually figure out what's in the ear of these other worlds. Okay. So because each molecule has its own characteristic absorbing pattern, right? Yeah. Okay.
Exactly. It's like a barcode. And if you think back to high school, like each chemical has a different structure, like water, H2O, right? It has an oxygen atom and two hydrogen ones. It looks a little bit like a triangle, nearly. And oxygen to oxygen atoms looks different. So the energy that needs to hit it to make it swing rotate needs to be different.
And light carries energy, so which one's missing tells me, like a stamp in a passport, what chemical is in the ear of this other world without me being able to get there? What's kind of nearly as cool as that? So what are you specifically looking for? What things do you, are you hoping to find or expecting to find?
So what we're looking for is when you look at the earth and try to figure out if this life on the earth, the combination of oxygen and a reducing gas, like methane, tells you that something is producing oxygen, methane, and huge amounts. So reducing means you take an oxygen away from where it once was? Exactly. If reducing basically means it reacts with oxygen and it will make, it still fits. Absolutely. It's a good stealer. And so it makes CO2 and water.
So if you see it together in the atmosphere of a plant ant, you need two sources that produce it. And from methane, it could be life, but also it could be volcanoes. What you're saying is that the methane and the oxygen, when left alone, are unstable, and they will disappear, unless somebody is cranking it out continually. Well, something is cracking it out. Exactly. Just love each other. Think about this. They love each other so much that they will actually dance and go and make CO2 and water.
So by them being together in the atmosphere, you can actually figure out that that's a fingerprint of life as we know it. Oh, because if it still exists, if it isn't disappearing, and you don't have a volcano that's causing it. So for the methane, the volcano could do it. But for the oxygen with the methane, the oxygen needs life to do it in those big quantities. But if it's just oxygen, it's not enough.
Because you could think about the long time, like our planet's been around for 4.55 billion years. So if you had one oxygen ever so often, let's say one oxygen atom a week, then it would build up. So you need the methane to grab it. You say one per week. If you had one or one per month, you're 4.5 billion years. Oh, God. This is why you need the methane. This is why it's key to have the reducing gas. Other than that, it could just build up, and you wouldn't know where it comes from.
Did you put all that in your book? I did. Alien Earths, the new science of planet hunting in the cosmos. And so the cool thing that when I think about these alien worlds, like some of them could be like ours, so they could be habitats, as we were just talked about. Hence alien Earths, not just alien Earths.
No, and this an S at the end, because the other way is also to think about it that way, when you look at our own planets through time, you wouldn't be able to say you and the Earths if you were at time travel, so that doesn't work like Einstein show. We can go back in time. But if you could, you would not be able to figure out its theorists, and probably not, you know, statue of Liberty Hand sticking out or something to tell you.
Wait, the statue of Liberty shows up in every science fiction movie. I know. So you know it'll be there. Yeah, so what were the other equivalent on other planets? Is this one of the things that you research? If they don't have the same kind of like hominid shape to their bodies, like their statue of Liberty would look weird to us. I do. It looks normal to them, but you know. It could be like lobster with a claw stick. Yeah, but still holding a torch. Clar holding a torch. Yeah, exactly.
I figured it would still have a torch in a crown. But like it would be maybe two crowns. It's good. It depends on how many heads it has and how many. But I think the good thing is, I think about it, it might be easier to spot, if it's like three legs or five legs. We only have one arm. Like how did they do it? One arm is stuck out. Wait, wait, so these are how biased are you? How biased are we?
I think we are scientists and you know, Neil, you also were thinking about life in the universe at one point, right? So I think we biased, but in a good way, because we have to be ultra conservative to tell you that we found life. We don't want to just make it up. And so what we do is we look for something that we cannot explain other than with life.
And keep our eyes open for things that are interesting, weird, and unexplained in terms of chemical makeup of a planet, or some kind of features like art, space art that blocks out some part of the starlight. So lots of ideas are coming in, but we have to be conservative to find it for sure. And then we have to have an open mind for something we don't know what to expect yet.
And this is all because we can't actually see the surface of the planet, to see if there are cities or people or whatever. So you got to do the secondary way to get in on there. Absolutely, but what's really cool is the next generation of telescopes that we're planning right now, the Habitat World Observer, for example, is supposed to be really big, so that you actually can block out the star's light, see the tiny, tiny planet next to it, and catch the light from the surface.
And thus, you know that you said about the biology in my name, right? In my professional description, I actually have a bio-dap. Where we grow, grow, live in all the different colors from all the different parts of the world, like deserts, like ice fields. Is she just saying she creates life in her bio-dap? She grows it. She grows it. She grows it. I'm not, I'm not, I'm not. I'm just verifying. I mean, you've never seen my kitchen, but we've been growing life there for a while as well.
There's, I'm not proud of it. But it's a bottle shop for the refrigerator. Yeah, there's some different colors. There's a little difference. I don't know what, like, I don't know what colorful ones send them out or what. All right. I'll chuck them, give me an address, give me a mailing address. Can I ask you if someone, like, you're equivalent on a different planet, on a different star, how to telescope pointing at Earth, what would be the markers of life that they would see for us?
That's exactly the question I had about two years ago. And with an amazing person here, the American Museum of Natural History, check it for RT, we actually went to figure that out, because we know where the stars are. There's an amazing mission called Gaia that's up there right now, that is having a look where all the stars are around us are. And we're like, where would we be the aliens?
And so we figured out that if you just have our level of technology, that means you need to have the planet go in front of the hot star. So you see the star ever so slightly being less bright for the Earth that would be once a year for 12.8 hours. Then they are within 300 light years, light from there to us. And the other way around about 300 years, they are 2000 star systems where we could be the alien and people could be wondering, ah, hopefully they are not that alien there.
We're pretty bad aliens. They won't think there's a life in unless they can see the Statue of Liberty sticking out. Right, right. Or something. I'm so only hoping that they also figured out that the gas combination will work because that lets you say that there's life in our planet for about two billion years. And that's how I got started in the field because I was part of the design team to build such a telescope to try to find other life on other worlds.
And we were looking for 21% of the stars that's right now, more than Earth. And I was like, the Earth changed, right? Right. And then people said, well, yeah, if using that's important to figure out, do it yourself. And I was like, very young and naive. I was like, oh, you can do this. Then I figured out how hard it was to do something that we had done in B4. And this is why we figured out it was two billion years. And you know, 4.55 billion years of history on the Earth.
But for half of it, think about it for the 24 hour clock. Since lunchtime, you can actually spot signs of life on the Earth. And so in a way, the news is out of the bag. If they just figured out our level of intelligence, and I'm having high hopes that there's more out there than just our level. We are intelligent at all. Exactly. We really find that. Let's physics on what you just said. I think technically, if you want to be physics precise, it's not that methane and oxygen are signs of life.
Is that methane and oxygen are signs of something out of equilibrium. And life itself is out of equilibrium. Maybe we need to be more creative about other things that could be out of equilibrium other than life. Is anyone thinking that way? What's really fascinating, and that was where like in 65, they started out with this combination of oxygen and methane, right? So it's like old school science. 1965. 1965. 1965. That's a Miller-Uri experiment. When around that time too.
But the idea was then to say, well, it's just a disequilibrium. But then we actually figured out that geology is super good in making disequilibrium. And sometimes life actually brings an atmosphere chemistry back to equilibrium. So there's only some very specific pair of gases that in disequilibrium would actually only be explainable by life. And so that's like new, right? Because you'd say like, okay, 1965, they figured it out, right? We've done stuff since then.
Even so, we haven't found life yet. But it's fascinating. This search tells us so much more about our planet too and how it works and how life works. So before we go to Q&A, because this is a cosmic queries, one question before we hand it over to you, Matt. I'm in. I'm ready. You collected the questions from our... Did from our Patreon members? And this is unsurprisingly. This may not be a shock, but this was one that brought in a lot of questions.
So I'm going to try and get through as many as I can. I'm excited. Okay, so let me just ask, what is life? Oh, such a good question and a whole chapter in the book. I have no answer. Is that blank pages after the one is life's question? It's just a picture of it. It's a huge shrugging, yes? It's really, really great because as an astronomer, I actually don't need to know what the basic, tiny definition of what life is.
Because I need a biosphere that changes my whole planet to a spot it somewhere else around another star. So in a way, I've put all the knowledge we have together, you know, that it basically can evolve, that it's starting evolution, that it has information content and so on and so forth. And that's an entity that's encapsulated. So I put everything together from biology, noble price winners, and other people I talked to, that one I didn't talk to, I actually read his book.
But I talked to the other people who do biology in the call-sign institute, and they're like, yes, no, no, yes. So I just do. That's a good sign. It means it's a vibrant field. It's a vibrant field. So I distilled everything I know. And then I did put a blank page for your work here. Did you? Oh my gosh! We were just joking. Yeah. Is it, is it, is it, what I'm making? I'm going to be honest with you. I think my version of my work here is going to be much help to the field.
But some other people might, some other readers of your book might take that bat on a run further than I can. I think my is more likely to be a shopping list. Great, here we go. And the first page is pretty cool too, because it has alien wannabes. Oh yeah, life on earth that would pass. If you would show it to me, right, without DNA testing, I would be like, oh my god, this is... And of course, here is the Tartagrade. Oh yeah. The stuff on earth that looks alien, basically, what that is.
And that survives things that it kind of, you don't know why it survives. Yeah, yeah. We know it's desiccation for the Tartagrats, but you know, if you would sell it as like an alien, you'd get pretty far until... Desiccation means you remove the water. You remove the water. And leave it for dead. Yes. And it's just doesn't care. And it's still has people as soon as it's a re... So here's the page where you draw on your own planets and life.
I gave you a couple of planets, but you can draw your own ideas here. Very, very thoughtful. See, this is what I wanted to science book. What? I want facts and information, but I also want doodling space. It's like a me too. And the really great thing is like, when you write your own book, you can do what you want. To a certain extent, if you can sell it. That's right, that's right. I'm Nicholas Castella, and I'm a proud supporter of StarTalk on Patreon.
This is StarTalk with Neil deGrasse Tyson. So Matt, bring it on. Given that you've just brought up sea creatures and other creatures on Earth that look alien, Craig Cordwell from the UK from my home planet says... Wait, it's my whole planet too. The UK is not a planet unto itself. I mean, we're still less. We have neither. We have neither. But not in New York City. You're going to get away with saying that. Okay, go on.
So Craig asks, how possible is it that life has landed on Earth from a meteorite and has just become another animal? He says, I'm pointing at the octopus here, but not exclusively. Who I'd love that? Octopus don't look like nothing else on Earth. And I've seen them land in the movie Arrival, so you know, they kind of look octopus like you. Octopus being right, right.
But the cool thing about this, if you think about where they could come from and people think about Mars or the planets, actually, the Earths had the best bet so far because it had watered the longest on a rocky surface. So the question is more like if we were to find life on Mars, maybe we're going to find out they're actually Earthlings that became Marslings. But of course, it sounds cool that if we might be Marslings or some other things would be... Did you say the word Marslings?
Well, I did. Did we get the idea to work for that already? Like, Martian? He's a movie called Martian. I know, I know. Nobody calls Matt Damon Marslings. Well, that's why you're the scientoid. This is the key thing that we haven't found life on Mars, so I can't say Martian, so I say Marsling. Just as a hypothesis.
Okay. But the cool thing is like if there were kind of different life, we would find out if we do our sciencey thing, where we basically check everything and see if the DNA is made out of exactly like everybody else's DNA chemistry wise, right? Then you don't get away with calling it aliens because for an alien creature, you'd hope that at least one chemical pair is going to be different to tell us. Right.
Because it seems quite unlikely that even if life's on another world, what I hope that it is exactly the same chemistry it will use. Why is that unlikely when if you talk to geologists, they see that similar minerals on other planets? Absolutely. They get to have the same rock formation process, but you are not going to recognize that maybe biology is universal. I think biology is universal. I didn't want to say that.
What I mean is like carbon scaffolding and water, I'll probably really, really good basis for life. But what nuclear pairs you could have taken for the DNA, you have so many options or for proteins. And there aren't so many options to make minerals. Exactly. Oh, gotcha. And so I think this is why because it's going to be so weird when, for example, we'd find it on Mars, right? Would it have been a Hitchhiker? We brought it.
If it looked exactly like the Earth, or is it life doing the exact same thing and a different environment down to the tiniest at? I bet everyone would bet on the Hitchhiker. Well, this is why we're going to the icy moons and hopefully just fly through the plume. I see moons of Jupiter and Saturn so that we don't contaminate those particular environments. And this is why it's called departments of NASA whose job it is to make sure we don't do that contamination, right?
Exactly. It's a job, but it's so hard to do because life is very hard to kill. Good thing. It's a good thing. Yeah, you should say that like a... She's trying to, ahh, I'm trying to kill it so quickly. Superman! I've got so many hammers and tried to buy. That's what she does most of the time in her lab.
The coolest thing is actually if you think about life on the Earth, you would actually have to melt our planet to about 10 kilometers down to actually eliminate life because this life down to about 10 kilometers. That deep. And so if you just... She's fond of our planet, it really likes that. She worries me. Matt, does it... Where you met? How do we also claim Earth? You're talking about how you get rid of life on Earth, melt it down to 10 kilometers.
Because we now know there are these extremophiles that can survive in volcanic gas. Or it's hard to raise, right? Yeah, yeah. You can't just boil Earth for two minutes. I think about it as more hopeful because even if we were stupid enough and I hope we're not, I actually destroy all of ourself. Destroying life is luckily so much harder than some other kind of bug might actually make it to the stars if we can make it. Let's just look at the extinction episode record.
Maybe we should be amazed we're all still here. There's a 90% extinction episode. The PT extinction, Permian Triassic, and then there's the famous one, the KT extinction. We lost 70% of species. I mean, the universe has been trying to kill life on Earth for years. And here we are doing a podcast. I really think this is later. This cool wonder that we hear and then we can actually figure out the secrets of the stars. Right? We can do that.
I actually think we should give this much more wonder and credit. And thus, like kids seeing exhibitions for the first time, look at the stars and knew we figure out what they are like. The wonder and majesty of it all. So Torsten Dekov from Berlin says it took evolution quite a while to develop multicellular life on Earth. How likely is it that most planets are populated only by bacteria or similarly simple life forms? Also great question.
So this two billion years of oxygen and methane combination gives you a range of life. What we don't know is how fast evolution could be in another world because we have only a sample of one hour. But we think with more and more oxygen, you get more and more complex life just seeing dinosaurs. There was more oxygen in the air, actually, when the dinosaurs were around, thus big creatures. And so right now we're 20, 21% what was it back then? We think 30 to 32.
And so the coolest thing is like Jurassic Park worlds would actually be easier to spot than us. And so we published this was pretty funny and then the headlines were like alien dinosaurs. Like, we didn't talk about alien dinosaurs. You can't put those two words in a title and have depressed, properly interpret it. But having said that, I saw it differently because if we now get everybody who loves dinosaurs to all love exoplanets, they have to, if we're looking for alien dinosaurs, right?
That gives us 100% of all kids. And I think that's exactly what we need to get to the stars. I feel like we're stealing them from the anthropologist and the paleontologist, but I'm okay with that. Wouldn't they learn so much more if they had other dinosaurs and other planets? Yes they would. See? It's just like we're helping out. Yeah. I mean, that is a way to get kids into science. Kids love space, kids love dinosaurs. That is a source of space. There it is.
And then if we tell them that you can go and talk to comedians who do funny things and be on the air and say, Hi mom, right? You know, what else is there that they would want? Maybe these superpowers. But you know, if you were on one of these other moons like Titan, because it has so much less gravity but a dense atmosphere, you could flap your wings and you could actually fly on Titan. You couldn't breathe, but you could fly. Yeah, you suffocate, but I've even that everything is flying, right?
You have a sea to fly, you're saying. You'd have a great 60 seconds or so. You could also come with a space suit. I'm not saying you can do that. So what's the gravity on Titan then? It's just much less than here. Yeah. Maybe it's a third. Moon is one sixth first. Yeah. So it'll be no more than half. Yeah. For sure. I think in somewhere around a quarter. Yeah. Sure. What do you weigh here on earth? Pounds do. This is America. No more money. 120? Yeah. Yes, on the moon, you'd weigh 20 pounds.
Just think about how high you could jump. And thus we have all the kids back. We have superpowers. We can give them. Yeah. You want to give them superpowers, dinosaurs and space. What more do you want? Be kind to others, your fellow scientists. Yeah. It does look fun-basing around on the moon. I mean, that feels like. The funny part is like when you see the astronaut skipping, right? That's what I show my students when I teach them, like, look, this is real life skills.
If you ever find yourself on the moon, you know that you have to skip. And skipping kids stop skipping, like, in middle school. Yeah, you should do that because you might find yourself on the moon. You've got to do not have to have skipping classes in NASA and training. I think they do. They do skip a no-water. Is it part of selection? I don't know that. Meal, do you know that? Have you ever tried out for an astronaut?
No. The underwater is just for zero G, not for low G. Right, but did you ever try out for the astronaut program and actually tried to figure out if you had to skip? No, no, I never did that. I never did that. That's a math you have to go and become our token astronaut to figure that one out. I mean, I think I'm still a good skipper. I think I can skip to a decent level. But you will have to do it for the East side, right?
The European Space Agency, who will have to figure out about their American system. Well, how does it work? I'm a way to get in citizenship. So I might be able to do my struggle both. You're a citizenship. Can I get the two patches? Okay. Why not? Yeah. Science is international. Also, that was great too. Invite us to the launch. All right. It's a deal. You heard it here first. So there's a couple of questions about different types of life form and different environments.
A victory Rutledge from Texas says, Can there be entities say life forms which exist outside of any planetary boundaries? And then Jono from Iowa also says, what are the extremes of environmental conditions that we think life could exist in? And we look for across the galaxy. I'd like that. So that would include planetary moons, maybe asteroids, comets, or just free floating in space. Are these legit places? I think it's really right. So the first ones are absolutely legit places.
So there's no reason a moon couldn't be a habitat. Or maybe even asteroid, even so there becomes a big tricky because it gets really cold. So you have to dig down deep. And in the moon and a planet, you have residual heat from being actually formed. So you could do that. Well, right. So the moon doesn't have a heat left over from being formed, but Earth dies, right? Right. Right.
Earth dies. Sorry. So if you have a moon, that's what they heat down under, like the mid ocean ridge and all these places. Exactly. And the other moons in our solar system are on the giant planets. They are actually being molded. So the other moons actually tuck on them as well as Jupiter or in the other system Saturn. And so there's tidal heat that gets generated. So they actually get warm and this is why we have oceans. We have tides on Earth that move in and out.
And we credit the sun and moon for that. So you're saying we have tides on moons of Jupiter. And then what effect does that have on them? Absolutely. So we have tides and moons of Jupiter. And so what it does is basically we have these ice balls because it's so far away from the sun. Right. It's outside the Goldilocks. It's outside of the Goldilocks sound. But because of this pulling and pushing that actually deforms those moons, they is heat that melts the ice on the ice shell on top.
And so we knew those ice shells actually swimming on liquid oceans. And so this is where we hide hopes that maybe those oceans could also have kind of life. And so this is where you can do sure it's a life in our oceans. No, that's a sensible thought. But it's a very different ocean. So this is why we sending things there to investigate. Oh, because it's much smaller and it gets like bent out of shape. And hopefully the bent out of shape has been since forever.
But for some of the moons, they are a little bit smaller like in cellulose that goes around Saturn. And so it's a very not so deep ocean. But we think it has been around for millions of years. But the question is, has it been around for billions of years? And how long do you need an ocean to get life? And so I completely high-check that question. So yes, life actually has some boundaries as we know. It's when you destroy the cell walls.
And when you make it so hot or irradiated so much, that everything breaks down the structure that basically lets you concentrate chemistry in the inner part of the cell. I like the way you're saying that. So I do know that molecules are held together by a certain binding energy. And if exterior to the molecule, there's more energy than that available. Just blast up the molecule. Exactly. And we are complex molecules. So you don't want to get busted up. You definitely don't want to get busted up.
And it's actually even earlier because you need the cell walls, because those allow you to get some chemistry in and some out. And so if you were swimming in a huge ocean, one of the key problems you have is to concentrate the chemistry enough to get something like DNA and RNA started, because you need concentration for that. Because you need the frequency of them bouncing into each other. Exactly. And the ocean is vast.
And I feel like a couple of molecules, one of them, are ever going to meet, right? Right. And the other thing is like when it gets too cold, we think these reactions are starting to be so slow that it might take so long for any of them to take place. So there are some limits on life. But so far, we think you need at least for starters, a rocky surface and some water, where you can concentrate the chemistry and make these kind of vesicles that become cells.
And then wherever you find those conditions, hopefully. But one of those questions was, we went, how many, the three and a half billion years with single-celled life? Is that somewhere around there, right? Absolutely. And the key point is that, that's a long time. That's a very long time, but there's two good things. So the stars that are older than us, and planets are as old as their stars, there's a star that's older.
Well, that was older than the Earth's now when the Earth's formed and it has planets. But also we have no idea what's set to the evolutionary clock. And so it could be faster evolution or slower evolution of words. It seems to me, Lisa, that if Earth went three and a half billion years with single-celled life, it could easily have gone another three and a half billion years.
And this is why this life-ladiescussion is so helpful in science, where people are actually now coming to the conclusion, or at least that's the best explanation we have right now, is that if you have enough energy available and that was the oxygen content in our air, then you will make more and more complex life. And it's not completely done yet, but that's the best explanation we have for now. So get oxygen.
So if you sneak some oxygen in early enough, we might have had our explosion of complex life sooner in the timeline of the Earth. That's basically what the biologists are telling me. And so at that point, because I'm an astrophysicist, even an astrobiology-leaning one, my knowledge gets a little bit less complete. So I talk to people. But it kind of makes sense. If you had energy available that life could easily use, you could become more complex. So the light becomes opportunistic?
Absolutely. Opportunistic is, I think, a great word for life of an air. So there's a kind of related question about the environment from Kevin Vale, from Chester New Hampshire, who says, I've always wondered how massive of a rocky type planet would carbon-based life still be possible? How much higher or low gravity might affect life? Ooh. And so that's a great question. So generally, gravity should mostly affect the structure. Let's assume everything's equal.
You have a rocky solid surface and you have some water. So then gravity affects your structure. You need enough pressure on top of your ocean, not to evaporate the whole thing, right? So you need that. So chemically, what you're saying is, if there's just vacuum above the water, there'd be nothing to keep the water in its liquid state. Exactly. You need the pressure of the air in order to maintain that, OK? Completely right.
And since my in-laws living Colorado is high altitude, we'll try to boil something. Yeah, water boils off pretty quickly. You dry out very quickly. Yeah, yeah, yeah. And that's a fraction of vacuum. Right, right. Or you could have an ice layer, like in the icy moons, right? That basically keeps your water below, protect it.
And so how small can you get as small as you allow me to have liquid water in a rocky surface and so those moons that get tidally heated, actually from the first principle without the tidally heating, they would be too small because everything would be frozen and cold, but because they're tidally heated. And physics works and the Holocaust mass, you basically get this additional liquid water. So what's too small depends on the circumstances.
Do you get pulled and pushed from your neighboring moons? Yes or no. And so we still learning the limits, but at one point, when it becomes so incredibly big, when it forms, it will actually grab on to all the gas that's around it and will become one of these big planets like Jupiter or Saturn. And so at that point, we don't know how you could have liquid water with a rock interface. It's not super critical liquid water because there's so much pressure on it and so hot.
You make an interesting point. So the more massive the planet, the more likely it would have retained gases that in Earth's history or Venus's history or Mars's history would have been long lost into space. Absolutely. So when we think about this really, it's like, why does the planet have an atmosphere and it's not the whole story? Then it's really the pull of gravity that the planet has versus the escape velocity. How fast you need to be. Of the molecules of the air.
Of the molecules in the air. So there's no such thing as a jumbo rocky planet. We don't think so. And so that's the really interesting thing again with the James Webb Space Telescope because what we found most of the planets, I've had thousands of planets, right? One out of five, maybe like ours, 200 billion stars in our galaxy alone, billions and billions of possibilities, even so, of course, he never said it.
But what's really interesting here is that the most common planets are some we don't have. They are bigger than the Earth's. And smaller than Neptune. So these super-Ears, great name, whether they're better, is absolutely not clear. How are they like? This is what we now figuring out. We don't know from first principles. We have some ideas. But the James Webb Space Telescope lets us look and confirm those. You did say billions and billions. The man wrote a book called billions and billions.
I know after everybody can say it. And then he went on to the show right and said, okay, now I say it officially. You know who first said billions and billions. Who did? It was Johnny Carson. Johnny Carson, right? From the Tonight Show. But he basically interpreted it as saying that Satan said it, right? Yeah, he was imitating Carl Sagan in an exaggerated way. He knew he said billions. And he said it so in a fun way. You got to double up on billions.
Plus there was a cartoon where there was a Carl Sagan as a child. It says, look at all the stars. There must be hundreds and hundreds of... Perfect. It's part of pop culture. Yeah, I did. In 1976, Carl Sagan published a paper with Ed Salpeter speculating on life in Jupiter's atmosphere. And till now you've only been talking about rocky surfaces.
And he was imagining Predator Prey, a combination of life forms that could sustain themselves without any care at all about the surface of anything, like balloons that had buoyancy, these flying creatures, living off the temperature gradients within the atmosphere. Is there much thought still given to that idea? I love that paper just because it shows the creativity that you need at the edge of the forefront of science. But we have learned more and more about the original life since then.
Luckily, science always learns. It was 50 years ago. It was 50 years ago. And it was a visionary paper. But what we've learned so far is that you need a rocky surface and some kind of water to get this chemistry going, to start it. But maybe... You can't just have molecules coming to your hand. You can't even... Convecting air cells. The chances that they're going to stick to each other and making kind of cell are just so small, even if you give it 4.5 billion years.
But having said that, once we have such floaty things, we could always bring them to Jupiter and reenact Carl Sagan and solve Peter's amazing paper. You've got to be our atmospheric zoo. Wow. There's some kid watching that. That's your task. That's your 50 years from now. That's going to be your job. That sounds great. I don't want to be a zookeeper there, too. So what else you got? Well, we've been dancing around this question and this idea a little bit.
Let's just ask it directly. This is from Gavin Trayba from Sacramento, soon to be Dr. Gavin Trayba. Oh, no. Are you guys a chemistry and molecular medicine? No, go for it. And Gavin wants to know, do you think the origins of human life on Earth are at least the basic building blocks, such as amino acids, came from the stars already formed from elsewhere, or were they originally synthesized in a pre-barte earth? So let me offer a version of that question back at you.
You guys always talk the talk when the amino acids are discovered on meteorites being delivered from space. You talk the talk. But Earth is made of all these same ingredients. Why do we need any ingredients from space at all if the birth ingredients of Earth has all of those ingredients all by itself? I really think it's more the glamour from everything that comes from space. Because you can't make the chemistry down here, too.
But it's kind of cool to find it on an esterate or a meteorite or another moon, right? It's got a cool factor. I think it has a coolness factor. It's different than any weights and necessarily no, which one's which? Yeah, like how would we know whether this amino acid became? At that point, we need the tardis, you may a nail, have to go in, and then get back to that point. Tardis, a doctor who's tardis, get point. Not just to the right time, but to the right location.
This is why I want the tardis, right? Because it gets you to where and when you want to be. Space and time. I'll figure out how life started here in the Earth then. Well, I think I know the answer to this, though. Go ahead. I think many amino acids have a chirality to them, where they are different in a mirror from what they are in real life. So there's a certain configuration of the atoms that is just not symmetric in a mirror.
Am I right in thinking that one way is good in the other way is evil? One has a goatee. That's how we tell. That's how you know. One way is good in the other one is just blah. Like, one is your favorite food and the other one is blah. So the amino acids that would have chirality on meteorites are 50-50, and all the ones on Earth are they left-handed or whatever, whatever is the handiness. So all life has only one handiness, but the ones from the meteorites have both.
Exactly. But the key point is that, did you need to bring them to the Earth so life had enough to eat? So the Siri would go that, you know, if we started out and we didn't have life yet, we probably had 50-50, and it's quite interesting that there are some researchers who say that it could have gone either way. But life just picked one, and that's the one it picked. And what's really fascinating too is that when we try to make life in the lab, we can't do that yet. That's the problem, right?
We don't know how life started because we can't do it in the lab. And so, to all the amazing colleagues, because before that, you said, I don't like engineers. I love engineers. I married to one. But basically, just to say, it is really hard to make life in the lab, and what you would want to do is you would want to make it with a different chirality. So you know you're making it from scratch, and that's so hard to do. But- Today, when the light just keeps the lab, you know we try to kill.
We know we're trying to kill. It's not going to kill you because you are blah. Right? It doesn't want to eat you. You can't digest you. It's a safety matter. But I bet if it's chasing you down the street, it won't know until after it's in your stomach that it couldn't digest you. That's evolution, and we have like billions of people, so hopefully, just don't be the one that it eats first. First, right? So we have time for like one more.
Okay, well, I like this question from Eduardo Labato from Spain, but living in Finland, but asking the question in English. And Eduardo says, does the discovery of dimethylsulfide on planet K218B by the James Webb makers rethink how probable life is in other worlds? And also what makes DMS a marker of life? So what's really interesting, one important one? Let's back up for a minute. So K2, that's one in the Kepler's catalog. Is that right? K2 stars slash 18B. Right. It's not like the other peak.
Yeah, the other mountain who just discovered it. We've discovered life on that mountain. It has a climate. It's a dead climber. Yeah. His name was Ben. He had feelings and found out. Oh, no. Come on. Okay. So it's so can we survive? This is catalog ID. K2, keep going. 18B. K218B. 18B. Okay. So now tell me about this molecule. So basically it's DMS dimethylsulfide, and on the Earth's life makes it. But now we have these other planets. We were just saying this super earth and many Neptune's.
We don't understand the geology. We don't understand the photochemistry. So even if we see gases that on the Earth in a chemistry like ours would actually indicate life, you have to be very careful not to misinterpret it. And that specific case is interesting because it tells us something new about this weird world. We don't have an solar system. We definitely tried to think about ways that life could be there.
But if you have so much gravity, you would have kind of a super critical ocean under a huge amount of hydrogen. And on the Earth's, the material that makes DMS needs light. And so there it would actually be dark. And so absolutely we're thinking about this a lot. And you can deduce all of this from just the James Webb. From spectroscopy, from basically looking at the light. And so what's really important about these discoveries that they may have been. It's still quite realistic.
Yeah. So these bacteria mind us. Well, this is a question, right? We haven't asked for the consent of spying on other potentially alien worlds. But we're doing it very kindly. No interaction. We're just looking. And then if you find something interesting, you know, that's what I was about to say. But we don't know the law there. So it's not just the engineers. It's also the lawyers who have to get up to speed. Right. Right. Right.
So it's intriguing. This planet is bigger than Earth, but not as big as Neptune. Is that right? So it's bigger than Earth, but not as big as Neptune. But the key point is it will be so different from the Earth that you shouldn't just go with the same conclusions when you find something that would indicate life on the Earth. And that's where we're learning. The more interesting planets we find, the more patterns we will see.
And the more we'll learn about geology, photochemistry, all these other worlds. Well, we just don't know because we never had one of those scenarios. If we're Earth-like planet, then you feel more confident. Oh my god. If we're an Earth-like planet, I would be so much more excited about it. But if you have the mini Neptune with a huge hydrogen atmosphere, no light hitting a potential ocean. We don't even know if the ocean is there. Then I'm just saying, maybe intrigued, but not sold yet.
There it is. I like that. Intrigued, but not sold. All right. We got to end on that. No, that's a very hopeful note, I think. I think the wonder... It's a curiosity-stimulating note that you just ended on. I think what's really great is that we live in this time, where for the first time we could figure out if we're alone or not, and all of us get to live in it, so that wonder that we all bring to looking at the night sky. Child-like wonder.
Child-like wonder? We could point up, count to five, say one out of five, might have another Earth, but... We're not a five of the stars, yeah. Stars, might host another Earth, but maybe in a couple of years, we could say, oh, that one. That one, just signs of life. And then you realize that that one's actually just a plain flying planet. That chose signs of life, dude. It does have signs of life, and if you want satellite, you can point across. Oh my gosh, Lisa, thanks for coming to town.
Thanks so much for having me. This was fun. And congratulations on the book, Alien Earths. You know, I had somebody called Neil Lagras, Tyson said he was good. On the back cover. Whoa! Yeah! Who's that guy? Let me see, let me get the hang on. Let me just see what that says there. Is that top blurb on the list? Of course, top. It's my duty, if I'm asked to blurb a book, to make the shortest blurb possible. It's still informative, and that usually ends up at the top.
Lisa, Captain Negger's breezy narrative style invites you to experience with her the challenges and joys of being a scientist on the frontier of discovery. Who said that? Who said that right there? Some guy Neil dig-grab, rassy, high school. It's like I... Lisa, congratulations on the book. Thanks for coming to town. Thanks so much for having me. All right, next time I come to your office, we have to re-enact some curl-sagant things.
Absolutely, I think it's going to be this year because it would have been called second-sign teas first day. You should come, we should sit there, and we both should think about what he's going to do there. All right, well, work something out, I promise. And Matt, good to have you here in person. Oh, it's a joy. So just show it, look at this. Look at this real real. Can I do that too? Yeah, that's what it is. Matt exists. He's not a bot in the most recent one. It's real, I'm not some avatar.
And he's very happy. He's set in the middle of us. He's just, that's what I came here for. I came here for the physical touch. We'll be locking it in real quick. It's really official. That's how you just think about it. Yeah, yeah, yeah, yeah, yeah. I'm a fan of you. I'm a fan of you. And keep that podcast going. That's it. That's it. And I finally remembered it correctly. You got it dead on. Probably science. That's the one. All right, all right.
After this interview with Lisa Kouttenegger, I'm reminded explicitly reminded that the best scientists out there are those who are still kids. What does a kid do? They turn over rocks, look behind trees. They're curious about everything, everything because the whole world is a frontier to them, a frontier of exploration. If you carry that into adulthood, then the universe is there to, for you to reach out and explore, discover.
And then you have to pick up some math along the way so that you can speak the same language that the universe does. But when you do, oh my gosh, what a joy it is to be a child again. Not many adults get to make that claim, but those adults on the frontier who are scientists do. That is a cosmic perspective. Till next time, start talking. .