Distant Aliens & Space Dinosaurs with Lisa Kaltenegger

Has JWST found potential alien worlds? Neil deGrasse Tyson and comedian Matt Kirshen learn about exoplanet discovery on the frontier, how higher oxygen gave us dinosaurs, and what type of life could be out there with astrophysicist and astrobiologist Lisa Kaltenegger.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Neil deGrasse Tyson?

  So Matt, after that conversation, I'm ready for life to be discovered on exoplanets like tomorrow.

• 0:05Matt Kirshen?

  I mean, I'm gonna need lunch first and then I think, I think we're good to go, right? I'm excited.

• 0:10Neil deGrasse Tyson?

  I'll feed you and then we'll learn about life in the universe.

• 0:12Matt Kirshen?

  No, just a salad.

• 0:14Neil deGrasse Tyson?

  Just a salad.

• 0:15Matt Kirshen?

  And, you know, we've been learning a lot about methane and stuff. I don't want anything too big.

• 0:18Neil deGrasse Tyson?

  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 lending its hand. Coming up on StarTalk.

• 0:33Neil deGrasse Tyson?

  Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:46Neil deGrasse Tyson?

  This is StarTalk. Field of grass Tyson here, your personal astrophysicist. And got with me as today's co-host, Matt Kirshen. Matt?

• 0:54Matt Kirshen?

  Hey!

• 0:55Neil deGrasse Tyson?

  And I have you in person.

• 0:56Matt Kirshen?

  I know, I know. It's been so long since I saw you not through a screen. Yeah, like it's real. You can, you can put Post-it notes on my actual face rather than just covering it on the screen like normal.

• 1:05Neil deGrasse Tyson?

  Is that what I do?

• 1:06Matt Kirshen?

  I imagine.

• 1:07Neil deGrasse Tyson?

  Well, welcome to town. Welcome to my office here.

• 1:09Matt Kirshen?

  It's lovely to be back.

• 1:10Neil deGrasse Tyson?

  At the Hayden Planetarium.

• 1:11Matt Kirshen?

  Yeah.

• 1:12Neil deGrasse Tyson?

  Of the American Museum of Natural History.

• 1:13Matt Kirshen?

  I mean, that's always exciting. It's, it's fun to come to work. It, does it get old? I hope it doesn't ever get old. The fact that you walk through the Natural History Museum to get to work.

• 1:21Neil deGrasse Tyson?

  It never gets old when I pass little children seeing exhibits for the first time. And I just remember when I was a kid.

• 1:30Matt Kirshen?

  The awe.

• 1:30Neil deGrasse Tyson?

  With that same experience.

• 1:32Matt Kirshen?

  Yeah, the natural wonder. I mean, it is.

• 1:33Neil deGrasse Tyson?

  Plus, if you come through at night.

• 1:35Matt Kirshen?

  Yeah.

• 1:36Neil deGrasse Tyson?

  Don't tell anybody, but all the animals come to life.

• 1:39Matt Kirshen?

  I've, I've heard the rumors. I've heard the rumors.

• 1:42Neil deGrasse Tyson?

  It's really true. So today is gonna be a cosmic queries.

• 1:47Matt Kirshen?

  Great.

• 1:47Neil deGrasse Tyson?

  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.

• 2:02Matt Kirshen?

  Some people have actual expertise in it rather than just...

• 2:04Neil deGrasse Tyson?

  Expertise? Maybe that's what I'm actually saying here.

• 2:06Matt Kirshen?

  Yeah, rather than people like me just, you know, looking up at night and going, "Ah, it's gonna be something, right?"

• 2:11Neil deGrasse Tyson?

  So I have with me Lisa Kaltenegger. Did I say that your name correctly? Kaltenegger.

• 2:17Speaker 02

  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.

• 2:26Neil deGrasse Tyson?

  You're a kid again! You're a kid again!

• 2:28Speaker 02

  And I do wanna know if at night the dinosaurs come alive? Because I'm here, we're just gonna record until night because I wanna say that.

• 2:35Neil deGrasse Tyson?

  You don't wanna leave, you don't wanna leave.

• 2:36Speaker 02

  No, no way.

• 2:37Neil deGrasse Tyson?

  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 had to pick it up on the side. But here is centerline with you. And you're Associate Professor of Astronomy at Cornell University. Who else was at Cornell? Somebody else?

• 2:59Matt Kirshen?

  I don't know, was there anyone?

• 3:01Neil deGrasse Tyson?

  It rhymes with Fagin.

• 3:02Matt Kirshen?

  Is there...

• 3:03Neil deGrasse Tyson?

  Reagan.

• 3:04Speaker 02

  Oh, oh, oh, let me just cut it...

• 3:05Matt Kirshen?

  Is someone involved in like, someone communication as well as research? Someone who wrote books and...

• 3:11Speaker 02

  There's this cool office on the third floor where Mrs. Kaltenegger is sitting right now, but it was the office that rhymed with Fagin.

• 3:19Neil deGrasse Tyson?

  Oh! So it's who got Carl Sagan's office? There's an answer to that.

• 3:23Speaker 02

  Me, me, me, me, me!

• 3:24Neil deGrasse Tyson?

  Wow! So I was...

• 3:27Speaker 02

  No pressure.

• 3:27Neil deGrasse Tyson?

  I was in that office 50 years ago.

• 3:31Matt Kirshen?

  Wow.

• 3:32Neil deGrasse Tyson?

  This not, uh, 49 years ago, I was in that office.

• 3:34Speaker 02

  You know what? If you come back and be in that office, just think about what's gonna happen then.

• 3:39Neil deGrasse Tyson?

  Oh! What kind of sorcery will you be... 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 gonna have all the books that you wrote on that shelf.

• 4:03Speaker 02

  And then my shelves are like all hickory, like I have like books piled, so I'm gonna just pull one and then the whole thing's gonna come towards you.

• 4:11Matt Kirshen?

  Yeah, I feel like if I tried that, I'd somehow pull the bookshelf onto me.

• 4:15Neil deGrasse Tyson?

  You are director of the Carl Sagan Institute.

• 4:17Speaker 02

  Absolutely.

• 4:18Neil deGrasse Tyson?

  And like I said, the answer to the question, who got Carl Sagan's office? And your research interests, you model habitable worlds.

• 4:25Speaker 02

  And so the great thing right now is we know of more than 5,600 worlds around other stars, other suns, if you want, you know. Of course, their name is not sun, 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, so not too hot and not too 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.

• 4:59Neil deGrasse Tyson?

  So why does the light tell you that there might be life?

• 5:03Speaker 02

  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.

• 5:12Neil deGrasse Tyson?

  Yes, we don't know anything without that, right?

• 5:14Speaker 02

  That's very true, if it's dark.

• 5:16Neil deGrasse Tyson?

  You can't go there, you can't put it in a Petri dish.

• 5:19Speaker 02

  Even so, I do have to say the engineer should do a bit more work, right? I've seen this on Star Trek and Star Wars, I can do it.

• 5:25Neil deGrasse Tyson?

  Now she wants him to go to the stars as well.

• 5:27Matt Kirshen?

  You heard it here first, engineers, you're all lazy.

• 5:31Speaker 02

  I'm just saying, abandon the other stuff, all pull together and make me an Enterprise, right? I would like to go to these cool stars we found.

• 5:38Neil deGrasse Tyson?

  Okay.

• 5:39Matt Kirshen?

  Do you wanna upset this fine scientist, engineers?

• 5:42Neil deGrasse Tyson?

  Can't satisfy us at all, okay.

• 5:44Speaker 02

  But you know what, the thing is like I'm even doing the blinky eyes if somebody gets me Starship Enterprise, I will do that, I can do that. If that's what it takes.

• 5:51Neil deGrasse Tyson?

  All right. So in the light, what's encoded there that is of value to you?

• 5:57Speaker 02

  So basically, when you have light, what we do as 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 thus, even though I can't set foot, I cannot set foot on these planets yet, I can actually figure out what's in the air of these other worlds.

• 6:20Neil deGrasse Tyson?

  Okay, so because each chemical, each molecule has its own characteristic absorbing pattern, right? Yeah, okay.

• 6:30Speaker 02

  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, has an oxygen atom and two hydrogen ones. It looks a little bit like a triangle nearly. And oxygen, two oxygen atoms, looks different. So the energy that needs to hit it to make it swing and rotate needs to be different. And light carries energy, so which one's missing tells me, like a stamp on a passport, what chemical is in the air of this other world without me being able to get there? What's kind of nearly as cool as.

• 7:04Matt Kirshen?

  So what are you specifically looking for? What things are you hoping to find or expecting to find?

• 7:10Speaker 02

  So what we're looking for is when you look at the earth and try to figure out if there's life on the earth, the combination of oxygen and a reducing gas like methane tells you that something is producing oxygen, methane in huge amounts.

• 7:23Neil deGrasse Tyson?

  So reducing means you take an oxygen away from where it once was.

• 7:26Speaker 02

  Exactly. Reducing basically means it reacts with oxygen and it will make, it steals it. Absolutely. It's a good stealer. And so it makes CO2 and water. So if you see it together in the atmosphere of a planet, you need two sources that produce it. And for methane, could be life, but also could be volcanoes.

• 7:46Neil deGrasse Tyson?

  What you're saying is that the methane and the oxygen, when left alone, are unstable.

• 7:53Neil deGrasse Tyson?

  And they will disappear unless somebody's cracking it out continually.

• 7:57Matt Kirshen?

  Or something is cracking it out.

• 7:58Speaker 02

  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.

• 8:15Matt Kirshen?

  Oh, because if it still exists, if it isn't disappearing and you don't have a volcano that's causing it.

• 8:21Speaker 02

  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, right? So if you had one oxygen, every so often, let's say one oxygen atom a week, then it would build up. So you need the methane to grab it.

• 8:49Neil deGrasse Tyson?

  Did you say one per week?

• 8:50Speaker 02

  If you had one or one per month, you have 4.5 billion years.

• 8:53Neil deGrasse Tyson?

  Oh, you can accumulate it.

• 8:54Speaker 02

  You can accumulate it. 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.

• 9:03Neil deGrasse Tyson?

  Did you put all that in your book?

• 9:05Speaker 02

  I did.

• 9:07Neil deGrasse Tyson?

  Alien Earths: The New Science of Planet Hunting in the Cosmos.

• 9:14Speaker 02

  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 just talked about.

• 9:22Neil deGrasse Tyson?

  Hence Alien Earths, not just Alien Aliens.

• 9:24Speaker 02

  No, and there's an S at the end because the other way is also think about it that way. When you look at our own planets through time, you wouldn't be able to say you're on the Earth if you were a time traveler. So that doesn't work like Einstein showed we can go back in time. But if you could, you would not be able to figure out it's the Earth and probably not, you know, Statue of Liberty hands sticking out or something to tell you.

• 9:45Neil deGrasse Tyson?

  Wait, the Statue of Liberty shows up in every science fiction movie.

• 9:48Speaker 02

  I know.

• 9:49Neil deGrasse Tyson?

  So you know it'll be there.

• 9:50Matt Kirshen?

  Yeah, so what would be their equivalents on other planets? Is this one of the things that you research? Like 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.

• 10:01Speaker 02

  I do.

• 10:02Matt Kirshen?

  It would look normal to them, but you know.

• 10:03Neil deGrasse Tyson?

  It could be like lobster with a claw sticking out.

• 10:05Matt Kirshen?

  But still holding a torch.

• 10:06Neil deGrasse Tyson?

  Claw holding a torch.

• 10:07Matt Kirshen?

  Yeah, exactly. I figure it would still have a torch and a crown. But like it would be maybe, maybe two crowns. It depends on how many heads it has and how many.

• 10:15Speaker 02

  But I think the good thing is like, thinking about 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? Like, this one arm stuck out.

• 10:23Neil deGrasse Tyson?

  Wait, wait. So Lisa, how biased are you? How biased are we?

• 10:27Speaker 02

  I think we as scientists and, you know, Neil, you also were thinking about life and 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.

• 11:11Neil deGrasse Tyson?

  And this is all because we can't actually see the surface of the planet to see if there's cities or people or whatever. So you got to do this secondary way to get in on there.

• 11:21Speaker 02

  Absolutely. But what's really cool is the next generation of telescopes that we're planning right now, the Halbert 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 and my name, right? And my professional description, I actually have a bio lab where we go grow life in all the different colors from all the different parts of the worlds, like deserts, like ice fields.

• 11:54Neil deGrasse Tyson?

  Did she just say she creates life in her bio lab?

• 11:57Speaker 02

  She grows it. She grows it. She grows it. I'm not, I'm not, no, no, no, no.

• 12:02Neil deGrasse Tyson?

  You know, I'm just verifying.

• 12:03Matt Kirshen?

  I mean, you've never seen my kitchen, but we've been growing life there for a while as well. It's uh. I'm not proud of it.

• 12:09Neil deGrasse Tyson?

  Especially if it's on the shelf with a refrigerator.

• 12:10Matt Kirshen?

  Yeah, yeah, there's some different colors.

• 12:13Speaker 02

  Right, right, Matt, so if you have any colorful ones, send them out.

• 12:16Matt Kirshen?

  All right, I'll chuck, give me an address, give me a mailing address. Can I ask you, if someone like your equivalent on a different planet, on a different star, had a telescope pointing at Earth, what would be the markers of life that they would see from us?

• 12:30Speaker 02

  That's exactly the question I had about two years ago, and with an amazing person here at the American Museum of Natural History, Jackie Farh-Ti, 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 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 there are within 300 light years, so light from there to us and the other way around, about

• 13:12Speaker 02

  300 years, there are 2,000 star systems where we could be the alien and people could be wondering, ah, hopefully they're not bad aliens there.

• 13:23Matt Kirshen?

  We're pretty bad aliens, I think.

• 13:26Neil deGrasse Tyson?

  They won't think there's life here unless they can see the Statue of Liberty sticking out or something.

• 13:30Speaker 02

  I'm strongly hoping that they also figured out that the gas combination will work because that lets you say that there's life on our planet for about 2 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 20%, 21% of our stars that's right now, modern Earth. And I was like, but the Earth's changed, right? And then people said like, well, yeah, if you think 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, so nobody had done it before. And this is why we figured out it was 2 billion years, and you know, 4.55 billion years of

• 14:13Speaker 02

  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.

• 14:30Neil deGrasse Tyson?

  That assumes we are intelligent at all.

• 14:32Speaker 02

  Exactly, we redefine it.

• 14:33Neil deGrasse Tyson?

  Let me lay some 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. It's 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?

• 14:57Speaker 02

  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.

• 15:05Neil deGrasse Tyson?

  Sixty five, I mean.

• 15:06Speaker 02

  Nineteen sixty five, sorry, nineteen sixty five.

• 15:09Neil deGrasse Tyson?

  That's the Miller-Urey experiment.

• 15:10Speaker 02

  Went around that time too, but the idea was then they said, well, it's just disequilibrium. But then we actually figured out that geology is super good in making disequilibrium. And sometimes life actually brings an atmospheric chemistry back to equilibrium. So there's only some very specific pair of gases that in disequilibrium would actually only be explainable by life.

• 15:34Neil deGrasse Tyson?

  Wow.

• 15:34Speaker 02

  And so that's like new, right? Because you'd say like, okay, nineteen sixty five, 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.

• 15:49Neil deGrasse Tyson?

  Yeah.

• 15:49Speaker 02

  And how life works.

• 15:50Neil deGrasse Tyson?

  So before we go to Q and A, because this is a cosmic queries, one question before we hand it over to you, Matt.

• 15:57Matt Kirshen?

  I'm in, I'm ready.

• 15:57Neil deGrasse Tyson?

  You collected the questions for?

• 15:59Matt Kirshen?

  I've got.

• 15:59Neil deGrasse Tyson?

  They're from our Patreon members.

• 16:01Matt Kirshen?

  And there's, 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.

• 16:07Neil deGrasse Tyson?

  Of course it would, I wouldn't.

• 16:08Matt Kirshen?

  This is a, this is a biggie.

• 16:09Speaker 02

  I'm excited.

• 16:10Neil deGrasse Tyson?

  Okay, so let me just ask, what is life?

• 16:15Speaker 02

  Ooh, such a good question and a whole chapter in the book and no answer.

• 16:19Neil deGrasse Tyson?

  Oh, is that, is it blank pages after the what is life question?

• 16:22Matt Kirshen?

  It's just a shrug, it's just a picture of shoulders going up.

• 16:24Neil deGrasse Tyson?

  It's just you shrugging, yes?

• 16:26Speaker 02

  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. Cause I need a biosphere that changes my whole planet for it to 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 during 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, Nobel Prize 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 Carl Sagan Institute. And they're like, yes, no, no, yes. So I distilled-

• 17:05Neil deGrasse Tyson?

  That's a good sign. It means it's a vibrant field.

• 17:07Speaker 02

  It's a vibrant field. So I distilled everything I know. And then I did put a blank page for your work here.

• 17:13Neil deGrasse Tyson?

  Did you? Oh, my gosh. We were just joking.

• 17:17Matt Kirshen?

  Yeah. I'm gonna be honest with you. I don't think my version of my work here is gonna be much help to the field. But some other people might.

• 17:25Speaker 02

  You never know.

• 17:25Matt Kirshen?

  Some other readers of your book might take that baton and run further than I can. I think mine's more likely to be a shopping list.

• 17:31Neil deGrasse Tyson?

  Right, here we go.

• 17:32Speaker 02

  And the first page is pretty cool, too, because it has alien wannabes.

• 17:36Neil deGrasse Tyson?

  Oh, yeah. Life on Earth that would-

• 17:38Speaker 02

  If you would show it to me, right, without DNA testing, I would be like, oh, my god.

• 17:43Neil deGrasse Tyson?

  And of course, here is the tardigrade.

• 17:45Speaker 02

  Oh, yeah.

• 17:45Neil deGrasse Tyson?

  Stuff on Earth that looks alien, basically, is what that is.

• 17:47Speaker 02

  And that survives things that it kind of, you don't know why it survives. We know it's desiccation for the tardigrades. But, you know, if you would sell it as like an alien, you'd get pretty far until-

• 17:57Neil deGrasse Tyson?

  Desiccation means you remove the water.

• 17:59Speaker 02

  You remove the water.

• 18:00Neil deGrasse Tyson?

  And leave it for dead.

• 18:01Speaker 02

  Yes.

• 18:02Neil deGrasse Tyson?

  And it just doesn't care.

• 18:03Matt Kirshen?

  And it still has the ability to re-

• 18:05Neil deGrasse Tyson?

  So here's the page where you've drawn your own planets and life and things.

• 18:08Speaker 02

  I gave you a couple of planets, but you can do all your own ideas here.

• 18:13Neil deGrasse Tyson?

  Very thoughtful.

• 18:14Matt Kirshen?

  See, this is what I want in a science book. I want facts and information, but I also want doodling space.

• 18:19Speaker 02

  Exactly, me too.

• 18:21Matt Kirshen?

  Yeah.

• 18:21Speaker 02

  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.

• 18:27Neil deGrasse Tyson?

  That's right, that's right.

• 18:40Speaker 03

  I'm Nicholas Costella, and I'm a proud supporter of StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 18:56Neil deGrasse Tyson?

  So Matt, bring it on.

• 18:57Matt Kirshen?

  Given that you've just brought up sea creatures and other creatures on Earth that look alien, Craig Caldwell from the UK, from my home planet, says-

• 19:04Neil deGrasse Tyson?

  Wait, it's my home planet too.

• 19:06Speaker 02

  Oh.

• 19:07Neil deGrasse Tyson?

  UK is not a planet unto itself.

• 19:09Speaker 02

  I was there last week.

• 19:10Matt Kirshen?

  We have an ego. We do, we have, we have an ego there.

• 19:13Neil deGrasse Tyson?

  You might think that, but not in New York City are you gonna get away with saying that. Okay, go on.

• 19:17Matt Kirshen?

  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."

• 19:27Neil deGrasse Tyson?

  Oh, I'd love that. Octopus don't look like nothing else on Earth.

• 19:30Speaker 02

  And I've seen them land in the movie Arrival, so you know, they kind of look octopus-like.

• 19:35Neil deGrasse Tyson?

  Octopus-y, right, right.

• 19:36Speaker 02

  But the cool thing about this, if you think about where they could come from, and people think about Mars or other planets, actually, the Earth 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 gonna find out they're actually Earthlings that became Marslings. But of course, it sounds cooler if we might be Marslings or some other things would be.

• 20:01Neil deGrasse Tyson?

  Did you say the word Marslings?

• 20:02Speaker 02

  Well, I did hypothesize-

• 20:05Neil deGrasse Tyson?

  Didn't we invent a word for that already? Martian? There's a movie called Martian.

• 20:08Speaker 02

  I know, I know, I know.

• 20:09Neil deGrasse Tyson?

  Nobody calls Matt Damon Marsling.

• 20:12Matt Kirshen?

  Well, that's why you're the Scientoid.

• 20:14Speaker 02

  This is, 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.

• 20:21Neil deGrasse Tyson?

  Okay.

• 20:21Speaker 02

  But the cool thing is, like, if there were kind of different life, we would find out if we do our sciency 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 gonna be different to tell us.

• 20:44Matt Kirshen?

  Right.

• 20:44Speaker 02

  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.

• 20:52Neil deGrasse Tyson?

  Why is that unlikely, when if you talk to geologists, they see that similar minerals on other planets?

• 21:00Speaker 02

  Absolutely.

• 21:00Neil deGrasse Tyson?

  Why do they get to have the same rock formation process, but you are not- Gonna recognize that maybe biology is universal.

• 21:10Speaker 02

  I think biology is universal. I didn't want to say that. What I mean is like carbon scaffolding and water are 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.

• 21:23Neil deGrasse Tyson?

  And there aren't so many options to make minerals.

• 21:25Speaker 02

  Exactly.

• 21:26Neil deGrasse Tyson?

  Oh, gotcha.

• 21:26Speaker 02

  And so I think this is why, because it's gonna be so weird when, for example, we'd find it on Mars, right? Would it have been a hitchhiker we brought if it looked exactly like the Earth? Or is it life doing the exact same thing under different environments, down to the tiniest atom?

• 21:42Neil deGrasse Tyson?

  I bet everyone would bet on the hitchhiker.

• 21:44Speaker 02

  Well, this is why we're going to the icy moons and hopefully just fly through the plumes.

• 21:48Neil deGrasse Tyson?

  Icy moons of Jupiter.

• 21:50Speaker 02

  Of Jupiter and Saturn, so that we don't contaminate those pristine environments.

• 21:54Matt Kirshen?

  And this is why it's whole departments of NASA, whose job it is to make sure we don't do that contamination, right?

• 21:58Speaker 02

  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.

• 22:06Matt Kirshen?

  Yeah, you should say that like a...

• 22:07Neil deGrasse Tyson?

  She's trying it. I've tried to kill it, so frustrating.

• 22:10Matt Kirshen?

  I've got so many hammers.

• 22:14Matt Kirshen?

  Tried fire, there's nothing, that's what she does most of the time in her lab.

• 22:17Speaker 02

  But 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 there's life down to about 10 kilometers. That deep. And so if you just sterilize...

• 22:31Neil deGrasse Tyson?

  She's thought about how to get rid of life on Earth. This worries me. Does it worry you, Matt?

• 22:34Matt Kirshen?

  How do we autoclaver?

• 22:35Neil deGrasse Tyson?

  Here's how you get rid of life on Earth: melt it down to 10 kilometers.

• 22:39Matt Kirshen?

  Because we know, we now know there are these extremophiles, right, that can survive in like volcanic gases.

• 22:44Speaker 02

  Or tardigrades, right?

• 22:45Matt Kirshen?

  So you can't just sort of, you can't just boil Earth for two minutes.

• 22:50Speaker 02

  I think about it as more hopeful because even if we were stupid enough, and I hope we're not, to actually destroy all of ourselves, 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.

• 23:03Neil deGrasse Tyson?

  Plus, if you 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 had been trying to kill life on Earth like for years.

• 23:22Matt Kirshen?

  And then here we are doing a podcast.

• 23:26Speaker 02

  I really think this 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 anew. We figure out what they are like.

• 23:43Neil deGrasse Tyson?

  The wonder and the majesty of it all.

• 23:46Matt Kirshen?

  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?

• 23:57Speaker 02

  Also, great question. So this 2 billion years of oxygen and methane combination gives you a range of life. What we don't know is how fast evolution could be on another world, because we have only a sample of one, ours. But we think with more and more oxygen, you get more and more complex life. Just think dinosaurs. There was more oxygen in the air actually when the dinosaurs were around, thus big creatures. And so

• 24:23Neil deGrasse Tyson?

  Right now, we're at 20, 21%.

• 24:25Speaker 02

  We're 21.

• 24:25Neil deGrasse Tyson?

  What was it back then?

• 24:26Speaker 02

  We think 30 to 32.

• 24:28Neil deGrasse Tyson?

  Oh!

• 24:28Speaker 02

  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." I'm like, "Whoa, whoa, we didn't talk about alien dinosaurs."

• 24:41Neil deGrasse Tyson?

  You knew that was coming. You can't, you can't put those two words in a, in a title and have the press properly interpret it.

• 24:47Speaker 02

  But having said that, I saw it differently, because if we now get everybody who loves dinosaurs to always love exoplanets, they have to if we're looking for alien dinosaurs, right?

• 24:55Neil deGrasse Tyson?

  That gives us 100% of all kids.

• 24:58Speaker 02

  And I think that's exactly what we need to get to the stars.

• 25:03Neil deGrasse Tyson?

  I feel like we're stealing them from the anthropologist and the paleontologist, but I'm okay with that.

• 25:08Speaker 02

  Wouldn't they learn so much more if they had other dinosaurs and other planets?

• 25:11Neil deGrasse Tyson?

  Yes, they would.

• 25:12Speaker 02

  See?

• 25:12Neil deGrasse Tyson?

  Yeah.

• 25:13Speaker 02

  It's just like we're helping out.

• 25:14Matt Kirshen?

  Yeah. I mean, that is a way to get kids into science. Kids love space. Kids love dinosaurs.

• 25:20Neil deGrasse Tyson?

  Dinosaurs and space. There it is.

• 25:22Speaker 02

  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 it is 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.

• 25:45Neil deGrasse Tyson?

  Yeah, you'd suffocate, but other than that, everything is fine.

• 25:48Speaker 02

  Other than that, right?

• 25:48Neil deGrasse Tyson?

  It'd be easy to fly, you're saying.

• 25:50Matt Kirshen?

  You'd have a great 60 seconds or so as you chokingly fly in a panic.

• 25:56Speaker 02

  You could also come with a space suit. I'm not saying you can't do that.

• 25:59Neil deGrasse Tyson?

  Mm-hmm, mm-hmm.

• 26:00Matt Kirshen?

  So what's the gravity on Titan, then?

• 26:02Speaker 02

  It's just much less than here.

• 26:04Matt Kirshen?

  Yeah.

• 26:05Neil deGrasse Tyson?

  Maybe it's a third. Moon is one-sixth Earth, so it'll be no more than half.

• 26:11Matt Kirshen?

  Yeah.

• 26:12Neil deGrasse Tyson?

  For sure.

• 26:12Speaker 02

  I think it's somewhere around a quarter, yeah.

• 26:14Neil deGrasse Tyson?

  Sure. What do you weigh here on Earth? Pounds, dude. This is America.

• 26:17Matt Kirshen?

  Uh.

• 26:18Speaker 02

  I have no clue about pounds.

• 26:20Neil deGrasse Tyson?

  120?

• 26:20Matt Kirshen?

  Yeah.

• 26:21Neil deGrasse Tyson?

  Yeah, so on the moon, you'd weigh 20 pounds.

• 26:22Speaker 02

  Just think about how high you could jump. And thus, we have all the kids back. We have superpowers. We can give them.

• 26:26Neil deGrasse Tyson?

  Damn, you want to give them superpowers, dinosaurs, and space?

• 26:30Speaker 02

  What more do you want?

• 26:31Neil deGrasse Tyson?

  Be kind to others, your fellow scientists.

• 26:34Matt Kirshen?

  It does look fun, bouncing around on the moon. I mean, that feels like...

• 26:38Speaker 02

  The funny part is like when you see the astronauts skipping, right? That's what I show my students when I teach. I'm like, look, this is real life skills. If you ever find yourself on the moon, you know that you have to skip.

• 26:48Neil deGrasse Tyson?

  And skipping, kids stop skipping like in middle school.

• 26:51Speaker 02

  Yeah, you shouldn't do that because you might find yourself on the moon at one point.

• 26:54Neil deGrasse Tyson?

  Yeah.

• 26:54Matt Kirshen?

  Yeah, do they have to have skipping classes in NASA and training?

• 26:57Speaker 02

  I think they do. They do skip underwater.

• 26:59Matt Kirshen?

  Is it part of selection?

• 27:01Speaker 02

  I don't know that. Neil, do you know that? Have you ever tried out for an astronaut?

• 27:04Neil deGrasse Tyson?

  No, the underwater is just for zero G, not for low G.

• 27:06Speaker 02

  Right, but did you ever try out for the astronaut program and actually tried to figure out if you had to skip?

• 27:10Neil deGrasse Tyson?

  No, no, I never did that.

• 27:12Speaker 02

  I never did that either. So Matt, you have to go and become our token astronaut to figure that one out.

• 27:16Matt Kirshen?

  I mean, I think I'm still a good skipper. I think I can still skip to a decent level.

• 27:20Neil deGrasse Tyson?

  All right.

• 27:21Speaker 02

  But you will have to do it for the ESA, right? The European Space Agencies who will have to figure out about the American system.

• 27:26Matt Kirshen?

  Well, how does it work? Because I'm on my way to getting citizenship, so I might be able to...

• 27:30Speaker 02

  Ooh, do both.

• 27:31Matt Kirshen?

  Can I straddle both?

• 27:31Neil deGrasse Tyson?

  US citizenship.

• 27:32Matt Kirshen?

  Can I get the two patches?

• 27:33Neil deGrasse Tyson?

  Okay, why not?

• 27:35Speaker 02

  Why not? Yeah. Science is international, so that must work too.

• 27:39Neil deGrasse Tyson?

  Invite us to the launch.

• 27:41Matt Kirshen?

  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. So Victor Ray Rutledge from Texas says, can there be entities, say, life forms which exist outside of any planetary boundaries? And then John O. 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?

• 28:02Neil deGrasse Tyson?

  I'd like that. So that would include planetary moons, maybe asteroids, comets, or just free-floating in space. Are these legit places?

• 28:10Speaker 02

  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 though there becomes a bit tricky because it gets really cold, so you have to dig down deep. And in a moon and a planet, you have residual heat from being actually formed, so you could do that.

• 28:29Neil deGrasse Tyson?

  Right, so the moon doesn't have heat left over from being formed, but Earth does, right?

• 28:33Speaker 02

  Right, Earth does. Sorry.

• 28:34Neil deGrasse Tyson?

  That's why they heat down under like the mid-ocean ridge and all of these places.

• 28:39Speaker 02

  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.

• 28:55Neil deGrasse Tyson?

  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 what effect does that have on the?

• 29:06Speaker 02

  Absolutely. So we have tides on moons of Jupiter. And so what it does is basically we have these ice balls because it's so far away from the Sun.

• 29:13Neil deGrasse Tyson?

  Right, it's outside the Goldilocks zone.

• 29:15Speaker 02

  It's outside of the Goldilocks zone, but because of this pulling and pushing that actually deforms those moons, there's heat that melts the ice under the ice shell on top. And so we knew those ice shells are actually swimming in liquid oceans. And so this is where we had hopes that maybe those oceans could also have kind of life. And so this is what you can do for a moon.

• 29:37Neil deGrasse Tyson?

  No shortage of life in our oceans.

• 29:39Speaker 02

  No.

• 29:39Neil deGrasse Tyson?

  Sensible thought.

• 29:40Speaker 02

  But it's a very different ocean, so this is why we're 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 Enceladus 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-checked 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

• 30:25Speaker 02

  in the inner part of a cell.

• 30:26Neil deGrasse Tyson?

  I like the way you're saying that. So I do know that molecules are held together by certain binding energy. And if exterior to the molecule, there's more energy than that available, just bust up the molecule.

• 30:39Speaker 02

  Exactly.

• 30:40Neil deGrasse Tyson?

  And we are complex molecules, so you don't want to get busted up.

• 30:45Speaker 02

  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.

• 31:04Matt Kirshen?

  Because you need the frequency of them bouncing into each other.

• 31:07Speaker 02

  Exactly, and the ocean is vast. And if there's like a couple of molecules, when are they ever going to meet, right?

• 31:11Neil deGrasse Tyson?

  Right.

• 31:12Speaker 02

  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.

• 31:40Neil deGrasse Tyson?

  But one of those questions was, we went how many? Three and a half billion years with single-celled life? Is that somewhere around there, right?

• 31:49Speaker 02

  Absolutely, and the key point is that-

• 31:50Neil deGrasse Tyson?

  That's a long time!

• 31:51Speaker 02

  That's a very long time, but there's two good things. So there are 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 is now when the Earth formed, and it has planets. But also, we have no idea what sets the evolutionary clock. And so it could be faster evolution or slower evolution in other worlds.

• 32:13Neil deGrasse Tyson?

  All I'm saying is, 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.

• 32:21Speaker 02

  And this is why this life-related discussion is so helpful in science, where people actually are 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.

• 32:44Neil deGrasse Tyson?

  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.

• 32:52Speaker 02

  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.

• 33:11Neil deGrasse Tyson?

  So the life becomes opportunistic?

• 33:14Speaker 02

  Absolutely, opportunistic is, I think, a great word for life, if we know it.

• 33:17Matt Kirshen?

  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 lower gravity might affect life?"

• 33:31Neil deGrasse Tyson?

  Ooh.

• 33:31Speaker 02

  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.

• 33:48Neil deGrasse Tyson?

  So chemically, what you're saying is- If there's this vacuum above the water, there'd be nothing to keep the water in its liquid state.

• 33:55Speaker 02

  Exactly.

• 33:55Neil deGrasse Tyson?

  You need the pressure of the air in order to maintain that, okay?

• 34:00Speaker 02

  Completely right.

• 34:01Matt Kirshen?

  My in-laws live in Colorado, it's high altitude.

• 34:04Speaker 02

  Trying to boil something.

• 34:05Matt Kirshen?

  Yeah, water boils off pretty quickly, you dry out very quickly.

• 34:08Neil deGrasse Tyson?

  Yeah, yeah, yeah.

• 34:09Matt Kirshen?

  That's a, and that's a fraction of a vacuum.

• 34:11Neil deGrasse Tyson?

  Right, right, yeah.

• 34:12Speaker 02

  Or you could have an ice layer, like in the icy moons, right? That basically keeps your water below protected. 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 tidal heating, they would be too small, because everything would be frozen and cold. But because they're tidally heated, and physics works in the whole cosmos, 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're still learning the limits. But at one point, when it becomes so incredibly big,

• 34:55Speaker 02

  when it forms, it will actually grab on to all the gases that surround it, and it 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, with not super critical liquid water, because there's so much pressure on it and so hot.

• 35:14Neil deGrasse Tyson?

  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.

• 35:27Speaker 02

  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.

• 35:39Neil deGrasse Tyson?

  Of the molecules of the air.

• 35:40Speaker 02

  Of the molecules in the air.

• 35:41Neil deGrasse Tyson?

  So there's no such thing as a jumbo rocky planet?

• 35:44Speaker 02

  We don't.

• 35:45Neil deGrasse Tyson?

  With only rocks?

• 35:45Speaker 02

  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 said 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 and smaller than Neptune. So these super Earths, great name, whether they're better is absolutely not clear. How are they like? This is what we're 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.

• 36:30Neil deGrasse Tyson?

  You did say billions and billions. The man wrote a book called Billions and Billions.

• 36:34Speaker 02

  I know, after everybody kept saying, and then he went on to the show, right? And said, okay, now I say it officially. And so.

• 36:40Neil deGrasse Tyson?

  Do you know who first said billions and billions?

• 36:42Speaker 02

  Who did?

• 36:43Neil deGrasse Tyson?

  It was Johnny Carson.

• 36:43Speaker 02

  Johnny Carson, right?

• 36:44Neil deGrasse Tyson?

  From the Tonight Show.

• 36:45Speaker 02

  But he basically interpreted as saying that Sagan said it, right?

• 36:49Neil deGrasse Tyson?

  Yeah, he was imitating Carl Sagan in an exaggerated way. He knew he said billions.

• 36:56Speaker 02

  I love.

• 36:56Neil deGrasse Tyson?

  And he said it so in a fun way, you got to double up on it. Billions and billions. Plus, there was a cartoon where it was like Carl Sagan as a child. Says, look at all the stars. There must be hundreds and hundreds of.

• 37:11Speaker 02

  Perfect. It's part of pop culture.

• 37:14Neil deGrasse Tyson?

  You got it. In 1976, Carl Sagan published a paper with Ed Saul Peter speculating on life in Jupiter's atmosphere. Until 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?

• 37:46Speaker 02

  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 origin of life since then. Luckily, science always learns.

• 37:59Neil deGrasse Tyson?

  It was 50 years ago.

• 38:00Speaker 02

  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.

• 38:12Neil deGrasse Tyson?

  But maybe. You can't just have molecules come.

• 38:15Speaker 02

  Floating around.

• 38:16Neil deGrasse Tyson?

  Convecting air cells.

• 38:17Speaker 02

  The chances that they're gonna stick to each other and make a 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's and Sal Peters' amazing paper.

• 38:33Neil deGrasse Tyson?

  That'll be our atmospheric zoo.

• 38:36Matt Kirshen?

  There's some kid watching that. That's your task. That's your 50 years from now. That's gonna be your job.

• 38:43Speaker 02

  That sounds great. I wanna be a zookeeper there, too.

• 39:06Neil deGrasse Tyson?

  So what else you got?

• 39:06Matt Kirshen?

  Well, we've been dancing around this question and this idea a little bit, so let's just ask it directly. This is from Gavin Traber from Sacramento, soon to be doctor Gavin Traber. RNA biochemistry and molecular medicine.

• 39:21Neil deGrasse Tyson?

  Ooh, go for it.

• 39:22Matt Kirshen?

  And Gavin wants to know, do you think the origins of human life on Earth, or 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 prebiotic Earth?

• 39:34Neil deGrasse Tyson?

  So let me, let me offer a version of that question back at you, okay? You guys always talk the talk when the amino acids are discovered on meteorites being delivered from space. You talk the talk, okay? 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?

• 40:00Speaker 02

  I really think it's more the glamour from everything that comes from space. Because you can make the chemistry down here, too, but it's kind of cool to find it on an asteroid or a meteorite or another moon, right?

• 40:11Neil deGrasse Tyson?

  It's got a cool factor.

• 40:12Speaker 02

  I think it has a coolness factor.

• 40:13Matt Kirshen?

  Is there even any way to necessarily know?

• 40:16Speaker 02

  Which one's which?

• 40:16Matt Kirshen?

  Yeah, like, how would we know whether this amino acid that became?

• 40:20Speaker 02

  At that point, we need the TARDIS. You, me, and Neil have to go in and then get back to that point in 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 wanna be.

• 40:35Neil deGrasse Tyson?

  Space and time.

• 40:35Speaker 02

  And figure out how life started here on the Earth, then we could tell.

• 40:39Neil deGrasse Tyson?

  I think I know the answer to this, though.

• 40:41Speaker 02

  Go ahead.

• 40:41Neil deGrasse Tyson?

  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.

• 40:57Matt Kirshen?

  Am I right in thinking that one way is good and the other way is evil?

• 41:00Neil deGrasse Tyson?

  Yeah, one has a goatee.

• 41:03Matt Kirshen?

  Yeah, that's how we tell.

• 41:04Neil deGrasse Tyson?

  That's how you know.

• 41:05Speaker 02

  One way is good and the other one is just blah. Like one is your favorite food and the other one is blah.

• 41:11Neil deGrasse Tyson?

  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 handedness. So all life has only one handedness, but the ones in the meteorites have both.

• 41:27Speaker 02

  Exactly. So but the key point is that did you need to bring them to the Earth so life had enough to eat? So the theory would go that, you know, if we're starting 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.

• 41:46Neil deGrasse Tyson?

  Yeah.

• 41:47Speaker 02

  But life just picked one. And that's the one it picked. And what's really fascinating too, is that when we're trying to make life in the lab and 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 lab. And so to all the amazing colleagues, because before that you said, I don't like engineers, I love engineers, 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

• 42:18Neil deGrasse Tyson?

  Then when the life escapes the lab.

• 42:20Matt Kirshen?

  You know, it wants to kill.

• 42:21Neil deGrasse Tyson?

  We know who wants to kill.

• 42:23Speaker 02

  It's not gonna kill you because you are blah, right? It doesn't want to eat you.

• 42:27Neil deGrasse Tyson?

  You're not interested. You can't, it can't digest you.

• 42:29Speaker 02

  Exactly. It's a safety measure.

• 42:32Neil deGrasse Tyson?

  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.

• 42:37Speaker 02

  That's evolution. And we have like billions of people. So hopefully just don't be the one that it eats first.

• 42:42Neil deGrasse Tyson?

  First, right. So we got time for like one more.

• 42:45Matt Kirshen?

  Okay. Well, I like this question from Eduardo Lobato from Spain, but living in Finland, but asking the question in English. And Eduardo says, "Does the discovery of dimethyl sulfide on planet K218B by the James Webb make us rethink how probable life is in other worlds? And also, what makes DMS a marker of life?"

• 43:05Speaker 02

  So, what's really interesting, one of the planets...

• 43:08Neil deGrasse Tyson?

  Let's back up for a minute. So, K2, that's in the Kepler's catalog, is that right?

• 43:13Speaker 02

  K2 slash 18B.

• 43:15Neil deGrasse Tyson?

  Right. It's not like the other peak in the Himalayas.

• 43:19Matt Kirshen?

  Yeah, the other mountain we've just discovered it. We've discovered life on that mountain. He has a climber.

• 43:24Neil deGrasse Tyson?

  It's a... It's a dead climber. It used to be alive, but...

• 43:27Matt Kirshen?

  His name was Ben. He had feelings and family.

• 43:29Speaker 02

  Oh, no, come on!

• 43:31Neil deGrasse Tyson?

  Okay, so...

• 43:33Speaker 02

  Can we survive?

• 43:33Neil deGrasse Tyson?

  That's his catalog ID. K2, keep going.

• 43:37Matt Kirshen?

  18B.

• 43:38Neil deGrasse Tyson?

  18B, okay. So now, tell me about this molecule?

• 43:40Speaker 02

  So, basically, it's DMS, dimethyl sulfur. And on the Earth, life makes it. But now, we have these other planets, we're just seeing these super Earths and mini Neptunes. 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 these weird worlds we don't have in our solar system. We definitely try to think about ways that life could be there. But if you have so much gravity, you would have kind of a supercritical ocean under a huge amount of hydrogen.

• 44:23Speaker 02

  And on the Earth, the bacteria that makes DMS needs light. And so there, it would actually be dark. And so, absolutely, we're thinking about this a lot.

• 44:32Neil deGrasse Tyson?

  And you can deduce all of this from just the James Webb data?

• 44:36Speaker 02

  From the spectroscopy, from basically looking at the light. And so, what's really important about these discoveries is that they make us think...

• 44:42Neil deGrasse Tyson?

  It feels almost voyeuristic, you know?

• 44:43Matt Kirshen?

  Yeah.

• 44:44Neil deGrasse Tyson?

  Because they're spying on you.

• 44:45Matt Kirshen?

  Do these bacteria mind us?

• 44:48Speaker 02

  Well, this is the 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 we find something interesting, you know, that's...

• 45:01Neil deGrasse Tyson?

  There's still probably a law against it. But that's right.

• 45:03Speaker 02

  I was about to say, but we don't know the laws there. So it's not just the engineers. It's also the lawyers who have to get up to speed.

• 45:09Neil deGrasse Tyson?

  Right, right, right. So it's intriguing. This planet is bigger than Earth, but not as big as Neptune. Is that right?

• 45:15Speaker 02

  So it's bigger than ours, 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. What we just don't know because we never had one of those in our system.

• 45:42Neil deGrasse Tyson?

  If it were an Earth-like planet, then you'd feel more confident.

• 45:45Speaker 02

  Oh, my God. If it were an Earth-like planet, I would be so much more excited about it. But if you have a 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.

• 46:02Neil deGrasse Tyson?

  There it is.

• 46:03Matt Kirshen?

  I like that. Intrigued, but not sold.

• 46:06Neil deGrasse Tyson?

  All right, we got to end on that note. That's a very hopeful note, I think.

• 46:09Speaker 02

  I think the wonder...

• 46:11Neil deGrasse Tyson?

  A curiosity-stimulating note that you just ended on.

• 46:15Speaker 02

  I think what's really great is that we live in this time where for the first time we could figure out if we are 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.

• 46:28Neil deGrasse Tyson?

  Childlike wonder.

• 46:29Speaker 02

  Childlike wonder. We could point up, count to five, say one out of five might have another Earth, but...

• 46:36Neil deGrasse Tyson?

  One out of five of the stars.

• 46:38Speaker 02

  Stars might host another Earth. But maybe in a couple of years, we could say, oh, that one. That one shows signs of life.

• 46:45Matt Kirshen?

  And then you realize that that one's actually just a plane flying over.

• 46:49Speaker 02

  That shows signs of life too.

• 46:50Matt Kirshen?

  It does have signs of life in it.

• 46:51Neil deGrasse Tyson?

  An Elon satellite just going across, right. Oh, my gosh, Lisa, thanks for coming to town.

• 46:56Speaker 02

  Thanks so much for having me. This was fun.

• 46:58Neil deGrasse Tyson?

  And congratulations on the book, Alien Earths.

• 47:01Speaker 02

  You know what? Somebody called Neil deGrasse Tyson said he was good. It's on the back cover.

• 47:07Neil deGrasse Tyson?

  Whoa!

• 47:08Matt Kirshen?

  Yeah! Who's that guy in that blurb?

• 47:10Neil deGrasse Tyson?

  Wait, wait, let me see. Hang on. Let me just see what that says there.

• 47:14Matt Kirshen?

  Is that top blurb on the list?

• 47:16Neil deGrasse Tyson?

  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 Kaltenegger's breezy narrative style invites you to experience with her the challenges and joys of being a scientist on the frontier of discovery.

• 47:39Neil deGrasse Tyson?

  Who said that? Who said that right there?

• 47:40Matt Kirshen?

  It's, uh, some guy Neil, Neil deGrasse Tyson. That's that guy.

• 47:49Neil deGrasse Tyson?

  Lisa, congratulations on the book. Thanks for coming through town.

• 47:52Speaker 02

  Thanks so much for having me.

• 47:53Neil deGrasse Tyson?

  All right. And next time I come to your office, we have to reenact some Carl Sagan things.

• 47:57Speaker 02

  Absolutely. I think it's gonna be this year because it would have been Carl Sagan's 90th birthday. You should come. We should sit there and we both should think about what he'd wanna do now.

• 48:08Neil deGrasse Tyson?

  All right, we'll work something out, I promise. And Matt, good to have you here in person.

• 48:12Matt Kirshen?

  Oh, such a joy. Such a joy. Look at this. Look at this. Real, real.

• 48:14Speaker 02

  Can I do that to you?

• 48:17Neil deGrasse Tyson?

  Matt exists. He's not a bot in Los Angeles.

• 48:20Matt Kirshen?

  It's real. I'm not some avatar.

• 48:21Neil deGrasse Tyson?

  Yeah.

• 48:22Speaker 02

  And he's very happy he said in the middle of us.

• 48:25Matt Kirshen?

  That's what I came here for. I came here for the physical touch. We've been lacking it recently.

• 48:28Speaker 02

  It's really a facial. That's how you should think about it.

• 48:31Neil deGrasse Tyson?

  A facial massage, yeah. And keep that podcast going.

• 48:36Matt Kirshen?

  Thank you.

• 48:36Neil deGrasse Tyson?

  Probably science.

• 48:37Matt Kirshen?

  That's it, yeah.

• 48:38Neil deGrasse Tyson?

  And I finally remembered it correctly.

• 48:39Matt Kirshen?

  You got it dead on.

• 48:40Neil deGrasse Tyson?

  Probably science. All right, all right. After this interview with Lisa Kaltenegger, 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.

• 49:22Neil deGrasse Tyson?

  Explore, discover. And 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. Until next time, StarTalk. Keep looking up.