Into the Impossible With Brian Keating - Aliens are Out There! Lisa Kaltenegger (#294)

Episode Date: February 2, 2023

Please support the podcast by taking our short listener survey: https://www.surveymonkey.com/r/intotheimpossible Lisa Kaltenegger is the founding director of the Carl Sagan Institute at Cornell. In 2009, Kaltenegger realized that a telescope like JWST would see only tiny signals from atmospheric gases during each transit, so in order to achieve any statistical certainty, astronomers would need to observe dozens or even hundreds of transits, which would take years. Acting on this insight, astronomers started to seek Earths in close orbits around dimmer, colder red dwarf stars, where atmospheric signals will be less drowned out by starlight and transits repeat more frequently. In 2017, astronomers announced the discovery of seven rocky planets around a red dwarf star called TRAPPIST-1. Then in September, the SPECULOOS-2 system emerged as a backup. These stars are close. They’re dim and red. They each have multiple rocky planets that transit. And as of the summer, the JWST is up and running even better than expected. It will spend a sizable fraction of the next five years staring hard at these messy globes of rock and chemicals spinning around their strange stars. For theoreticians like Kaltenegger who went from daydreaming of alternate Earths to churning out predictions about their atmospheric chemistry, decades of anticipation have given way to a slow fade-in of squiggly spectra on computer monitors. The goal at the time was to compare spectra from rocky, temperate planets to what Earth’s spectrum would look like from far away, seeking conspicuous signals like a surplus of oxygen due to widespread photosynthesis. Kaltenegger’s objection was that, for the first 2 billion years of Earth’s existence, its atmosphere had no oxygen. Then it took another billion years for oxygen to build up to high levels. And this biosignature hit its highest concentration not in Earth’s present-day spectrum, but during a short window in the late Cretaceous Period when proto-birds chased giant insects through the skies. Without a good theoretical model for how Earth’s own spectrum has changed, Kaltenegger feared, the big planet-finding missions could easily miss a living world that didn’t match a narrow temporal template. She needed to envision Earth as an exoplanet evolving through time. To do this, she adapted one of the first global climate models, developed by the geoscientist James Kasting, which still includes references to the 1970s magnetic-tape era it originated in. Kaltenegger developed this code into a bespoke tool that can analyze not only Earth through time but also radically alien scenarios, and it remains her lab’s workhorse. Follow Lisa https://twitter.com/KalteneggerLisa Join the Carl Sagan Inst: https://carlsaganinstitute.cornell.edu Read How to Characterize Habitable Worlds and Signs of Life https://www.annualreviews.org/doi/abs/10.1146/annurev-astro-082214-122238 Connect with Professor Keating: 🏄‍♂️ Twitter: https://twitter.com/DrBrianKeating 📸 Instagram: https://instagram.com/DrBrianKeating  🔔 Subscribe https://www.youtube.com/DrBrianKeating?sub_confirmation=1 📝 Join my mailing list; just click here http://briankeating.com/list ✍️ Detailed Blog posts here: https://briankeating.com/blog.php 🎙️ Listen on audio-only platforms: https://briankeating.com/podcast Subscribe to the Jordan Harbinger Show for amazing content from Apple’s best podcast of 2018! https://www.jordanharbinger.com/podcasts  🎧 On Apple devices, click here, https://apple.co/39UaHlB scroll down to the ratings and leave a 5 star rating and review The INTO THE IMPOSSIBLE Podcast. Other ways to rate here: https://briankeating.com/podcast Support the podcast on Patreon https://www.patreon.com/drbriankeating  or become a Member on YouTube- https://www.youtube.com/channel/UCmXH_moPhfkqCk6S3b9RWuw/join Learn more about your ad choices. Visit megaphone.fm/adchoices

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See Home Depot.com slash price match for details. think about it this way, if in the far, far future, somebody sets out to another planet, they might have this tiny antique map, you know, from the first time when scientists got around to say, oh, this might be an interesting planet. And they might just look at it, and there might be smiling and laughing a little bit, like when we look at the antique groups. But maybe I was a person who put those planets on the map. And so even if I'm not there in person, what I did will then travel through the stars.

Welcome everyone to this episode of Into the Impossible on the ever-trending existential questions. Are we alone in the universe? Are there really billions of Earth-like planets that could harbor life? And if there are, where is everybody? One of our planets leading scientists and thinkers on astrobiology is host Brian Keating's guest on this episode, Lisa Kaltinecker, founding director of the Carl Sagan Institute at Cornell. Could there be a more illustrious legacy for this subject than Carl Sagan? Come along into the Goldilocks Zone as we learn about the cutting edge of exoplanet research and the incredible interdisciplinary approaches to answering some of the humanity's most persistent questions about the origin and evolution of life on Earth and beyond.

Any sufficiently advanced technology is indistinguishable from magic. Open the budd bay doors, please, hell. One of my favorite finds from around the universe, that's Dr. Lisa Kaltanager, of Cornell University. She is the Carl Sagan Center founding director, where she's been in that role since at least 2015. And I brought along my only prop today. I have two props. I've got some samples of a proto planet that never formed,

aka a meteorite. And then I have this guy here. You recognize this guy? Of course. Carl Sagan. We're talking about Cornell University and the Carl Sagan Institute. So there was a reason why we actually came here and why the inspiration for searching for life in the universe is just so deeply rooted at Cornell. Yeah, and I had my roots there almost.

I was almost born at Cornell. My father was a professor there, and he left just a couple of years before I was born to go down to Stony Brook down the south. We'll take it. You are Cornellian right now. You know, it's just one of these things. Well, Lisa, I'm glad that you say that because the admissions officers did never say that, not for undergrad and not for grader. graduate school. We're not, I'm not bitter, Lisa. I'm not bitter. But I have had the honor of how you're not the first Cornelian, not to be on or the first Ithaconian or whatever, Ithacan, because I've had on both Andrurian,

Carl Sagan's lovely, lovely writing partner, spouse, muse, and also his daughter, Asha Sagan. They've both been guests on the podcast. My first. Amazing. Yeah, my first ever mother-daughter, you know, kind of team up. And that was just delightful. So Carl looms large over almost everything, you know, that we think about in the search for other worlds, but even in things ranging from the search for our own humanity. And I wonder we'll get into a discussion of whether or not Carl's dream of detecting the Earth from a distance could be made more visualized by the work that you're doing. You're a theorist, but you work very closely with observations, with forecasting. I was telling you before we started broadcasting that I had always known of your work.

And actually, we had been scheduled. I've been scheduled to give a colloquium there. I think it's still waiting for you. March 2020. I don't remember what happened back that. It's all a blur. But I will come back. But I was, of course, aware of you for so long.

Your reputation is so well deserved. And you do so much not only in the public sphere for, for, you know, popularizing the work that we do. And I think that's a moral obligation. that scientists have to give back to the public because they pay our salaries at some level or they funded our education. But more than that, you do a great service to the scientists in your field by providing a benchmark of what a good scientist looks like and how they should approach a field,

both interacting with experimentalists like me, observers like past guests on the show, and, of course, with theorists. And today we're going to be talking about your work inspired by this Quantum Magazine article most recently that is rumored to be one of their most popular. I don't want to make any of my friends jealous or betray any secret. I did talk to the editor Thomas there not too long ago, and he said it was one of their most popular ever, and it's well deserved.

So Lisa, we're going to talk about your work. But first, I do want to start with your quick origin story. How did the origin of life, the life of Lisa, get started? Please give us a brief intro into what brought you to being the founding director of the Sagan Institute. Well, I am actually from a tiny, tiny town in Austria, so they are always a very, about a thousand people in that time. And whenever I come back, they still wave out of the car at me. And I was like, oh, you're back, you know, that kind of town.

And from that, it was actually never really in the carts, I thought, to become a university professor, you know, small country, not really a space agency. But in Austria, we can choose what we pick to study. And so I was curious about everything around me. You'll see that probably is one of the things that might work. I think an exoplanet is so fascinating to me, especially in Earth-like one, because there's so many puzzle pieces that you need to put together

to understand what you're seeing or to figure out what you need to now observe with this big telescopes. And by the way, I'm a theorist right now because we didn't have telescopes that could do it. So I'm starting to get closer and closer to an observer aspect. And I'll tell you about all the stuff I grow in the lab. So I'm actually starting to become an experimentalist, too, because it's a lot of fun to put these pieces together. but yes, theory is definitely the core of what I do. And so in 1995, when I started to study,

they found the first planet around another start. And the people who found them are just incredibly nice people. I met them at a conference like Michel Mayor and Didier-A-Kalos. They're just great. And the interesting thing is they're both Swiss, right? And they found them in Switzerland. So Switzerland has a lot of mountains. Austria has a lot of mountains.

Switzerland is pretty small. Austria is pretty small, right? And I was like, hey, if they can do this, then maybe, just very, very maybe, you know, I can do this too. But of course, I saw nobody who looked like me anywhere. So then I went to my first meeting in Karshais, like in Korsico. It was like a tiny meeting and it was in 98, so three years after. And they were, I think we were about 50 people. So I shared a room with Sarah Seeger because, you know, we were just four girls and the whole thing.

Past guest on the pod, past three-time guest on the podcast. Perfect. And so basically, that's where I got. to me a lot of super interesting people in, I saw that this hierarchy can break down. So there was like this esteemed professor asking my opinion about things that I didn't know much about because I was an undergrad at that time. And then they were saying, well, we're looking, we're trying to figure out how we could find life in these planets. And I'm like, oh my God, is there really an option that I could help trying to figure out if we're alone in the universe?

And I think from there, it spiraled insofar that I was like, okay, maybe it's really true. maybe I can really do something like that. And then I went to the European Space Agency to do part of my PhD that were looking for young engineers and have an engineering degree and a science degree. So that worked out well. And I only applied for one mission. It was called the Darwin mission. And it was supposed to search for planets like ours and figure out if there was life. And from all these applicants, they picked me what was really interesting because I was like, why do you do that? But apparently like having engineering optics, background and the theory. background in astronomy was not as usual. So then I went to Holland and then from there it kind of went the way that we designed a telescope to try to find life and we'll get to that when we talk a little bit more about work. But the interesting thing was like nobody could tell me how the Earth would have looked like earlier. We were looking for a carbon copy of modern Earth in all our design choices. And I was like, but what about if the Earth is younger, right? I can't tell you what's going happen if the years is older because we don't have any data yet, we just have models.

And nobody knew. And so then basically, I talked to somebody at Harvard, what was pretty funny, right? So I'm in this meeting, I'm talking about that we really need to model the evolution of Earth through time. And nobody's taking me up on it. And I learned why, because it's so hard to do, you know, the naivete about this is possible. It's a lot of energetic capital in the beginning when you're trying to do a huge project, as you well know. And then West Trowb at Harvard-Smithsonian Center for Rastrophysics said, well, if you think you need to do this, you know, then you'll just have to do it yourself. You know, if you think it's worth doing, you have to do it. And so this is how I then went to Harvard. And then from Harvard, I went and built my team at the Max Blanc Institute in Germany when they were saying, ooh, maybe you want to build our team here.

And I was like, yeah, I can do that. And coming back, you know, to Europe was also a great choice. And then Cornell called and they were saying, well, you know, we would really like you to come here. And so I think that was the first time I actually knew where Connell was. And I also was the first time I ever went to Cornell. So, you know, you have some time still. So that phone call was incredibly pleasant. And then they were saying, well, what will convince you to come and join us?

And I was like, well, I really want to work in this interdisciplinary team. that's basically one of the key things in my research. I think if you understand the planet, you need to understand the biology, you need to understand the chemistry and the engineering to figure out how to find it and so on. And I can do quite some of it, but not all of it. There's no way we can do this anymore, right, to know everything there is. And so I said, well, I want to work in this institute. And then they turn around and it's like, well, if you think it's worth doing and having this

institute, you'll have to build one and lead it. Again. I saw that coming. I should have seen that coming. in the best possible way. This is how the Colossagan Institute here got started. In my workroom, I bribed people from all the different departments with really good coffee. So my startup was spent very well on coffee machines and espresso machines and then, you know, dark Belgium chocolate and some good cake.

So if you ever come by and want to talk about research, you know, we have the best coffee on campus. And so we have an incredibly striving team because, you know, scientists do like good coffee and good sweets. Not a place for diaries. And great things to talk about. Yes. Not a place to go on a d. That's true. Well, I am just blown away by kind of the essence of what you're doing.

And I always feel like it's a question for me, you know, how do you understand a project when there may not be an answer at the end? And you may not be successful detecting life. And that's okay. And I might not be successful detecting, you know, waves of gravity from the early universe. And that's okay, too. But on a daily basis, what keeps you going? I mean, is it the knowledge that there are so many planets? I mean, as Androian and as Carl Sagan write in their book, Contact, which became a famous movie, loosely based on other Cornell and two-time guest on the show, Jill Tarter, who's maiden name.

Do you know what her maiden name was? No, I don't actually. Cornell. I'm almost positive. It's Cornell. Someone in the chat room, correct me if I'm wrong. But anyway, and she was at Cornell, obviously. and she is still a towering figure and a mentor to millions around the world.

But, you know, as they write in that book, if there isn't life in the universe, it's an awful waste of space. And I never liked that because I've been to Antarctica twice, which isn't, you know, quite as luxurious with replete with chocolate as is Austria or Belgium or now it sounds like Ithaca. But I've been there twice and, you know, it's one seventh of all the continents on Earth. And so you might think naively, if you're just a dumb experimentalist like me, you might say, well, they must have one seventh of the life on Earth there. And it's like 0.1% of all the life on Earth. You know, it's a couple of penguins, which are really cute. And some nasty birds called scoos, which are like literal, like like seagulls on steroids that will eat anything, chocolate or not. They'll eat your luggage. But that's about it. And there's some,

there's 200 nerds, you know, on the planet in the middle of winter down there, which is coming up in about six months. But anyway, Lisa, the supposition that, you know, space is tantamount to probability has always troubled me about your field. So I'm not putting you on the spot. I hope too much. But what do you make of this argument that, well, there's so many, you know, planets in the universe, there has to be the potential for life. What do you make of those kinds of arguments? Well, let me go. One point just about what you were talking about life. There's actually I have an amazing postdoc right now. She was a PhD student with me who went to Hudson Bay and scooped up this lifeless goo. And we found like such a diversity of

biota in there, like not penguins. I would have left the picture of the penguin. Luckily it's also not polar. It's not right. But there are so much diverse microbial life in there. And then you just kind of have to imagine that if these were the main condition on a planet, there could actually be advances in that kind of life form too that we just don't see here because it's just niche environments as you were saying. And so I agree. But let's come back to your question. Absolutely.

So is it a numbers game? And I like to use like, may the numbers be forever in our favor, right? Because we know that one out of five stars from everything we know from the small region and around our star, like about thousand, two thousand light years around where we actually look at planets around other stars, we find that one out of, well, one out of two at least has a planet. and one out of five, that's the amazing number, has a planet that's small enough to be a rock and at the right distance to not be too hot and too cold.

So, but I agree with you. Now, how do you go from that huge number, 200 billion stars in the galaxy? So one out of five roughly gets you to 40 billions. Of course, you have to be careful because in the middle, there's a black hole, much more stellar density. There might be not enough metals in some regions, but we're talking billions and billions. You know, basically channeling calls, like it on this show. But we're talking possibilities, right?

But now what's really fascinating is that we can make life in the lab. That was one thing that, for example, I didn't know. Yes, I should have known, but I didn't know that we can't do that. And so if we can't make life in the lab yet, we do not know if small changes in the initial conditions could actually leave a planet baron if you want. or if they are huge changes in condition and still life will evolve maybe differently, right? Because on the earth, we also think it got a couple of starts, but we don't know that. And so this is why I agree with you, if you have like a couple of billions multiplied by zero.

Yes. You still have zero. And I love, if you multiply by one, you have a huge number, but I love, Michelle Mayurr got this question in one of the talks when I was at Harvard. And they were like, so what's the probability of life? And Michelle was so funny. He said, 50%. And then he was like, oh, my God. And he said, plus minus 50.

And that's exactly where we are. And this is in a way why this is so fascinating, right? Because if we knew already, it wouldn't be cutting at research anymore. If you knew that the gravitational waves would come from the beginning of the big bang or just slightly after, you know, what would be the fun and trying to puzzle out how to potentially do it? And you were asking how I feel about, you know, this stage in our time. Maybe I'm going to find life, hopefully.

Maybe not, right? And what I love about science is that we are connected through time. We basically, I use things that Kepler found. I use relativity, you with repetitive that Einstein put together. And so to me, the scientific knowledge is in a way like this huge firmament. this other kind of sky where we all are like tiny points that adds something to it. And with that we're creating the knowledge that puts humanity forward. And yes, of course I want to find life in the universe, not even a question, but maybe if I can't, my contribution will allow the next

person to step off there and find it. And when I talk to my students, I think about it this way. if in the far, far future, and I hope we're going to get a Star Trek kind of spaceship, right? Somebody sets out to another planet, they might have this tiny antique map, you know, from the first time when scientists got around to say, oh, this might be an interesting planet. And they might just look at it and there might be smiling and laughing a little bit like when we look at the antique globes. But maybe I was a person who put those planets on the map. And so even if I'm not there in person, what I did will then try. travel through the stars. That's delightful and true.

And I want to, first, I want to make an offer, even though I wasn't accepted at Cornell, two times. Grads. I'm not going to dwell on this. Their fault. I'm not bitter. I'm not bitter at all. It doesn't sound as if you are.

I'll come back for that chocolate. I want to turn very briefly to your thoughts as a theorist as an astrophysicist on the, what we can say statistically about objects like this. I told you I've got two props. One is Carl Sagan. This is a meteorite, which was discovered in Argentina, the so-called Campo de Scello in about three or four hundred years ago. And I bring this up because of two things.

One, I'm going to give them away to your students. Anyone with a dot edu email list automatically wins one of these. And the rest of you, non-educated Cornell or not, by the way, it could be anywhere that with a dot edu address. So if you join my mailing list, which is linked right over there, you will get your own sample. I'm going to bring you a much bigger sample when I come visit you, Lisa. But what can we say about the fact that there's material exchanged all around the solar system for millions of years, including from, I have a tiny, tiny fragment of Mars. I have a smaller sample of the moon.

And these were all not captured by me as an astronaut going, obviously, because we haven't been to Mars. But it was brought by gravity in the U.S. Postal Service to my lab. And we examine them and you get some data about these guys when you join the mailing list. But anyway, the point is we've been receiving material from all these different planetary bodies in our own backyard. And that implies, if I'm not mistaken, you'll correct me. But there's material from Earth that could have made it to other regions of our own solar system, including these potentially fertile places like Enceladus and maybe Phobos. I don't know.

You'll correct all the errors that I'm probably making. But what can we say about the non-observation of life in our own solar system as a laboratory? you're thinking the solar system as an extremophile laboratory. What can we say? Can we say that there's less chance that there's even slime mold or those protozoa that were in your brilliant postdoc samples from Hudson Bay? What can we say about the non-observation of any form of life in our own solar system where there's definitely one source of life, it's here on Earth, and it's been exchanging

material for least a billion years since life has been in existence? Can we say anything in a Bayesian sense about the probability or not of life existing throughout the cosmos. So what's really interesting in this, and I love that you brought the props, is that, yes, you can have microbial life, right? But if, even if you have the most dirty microbial life, if you throw it into a completely different kind of condition,

it doesn't need to strive, right? If the conditions are similar, it can't, but if it's different, it can't. And so this is really interesting body of research and there's no conclusion yet, how big such a meteorite would have to be to bring enough material with it to allow the biota to actually adapt to the conditions outside, right? So you'd have to survive for a while in the condition that you brought.

And then you could try to adapt to the conditions outside. And there is no consensus how much material that would be. But most of the consensus is that these small pieces are not enough because they just don't give you enough nutrition, they don't give you enough solvent, whatever you're using. But on the flip side, it was really funny. And I love that you brought, you know, that the Earth, of course, shed those asteroids as well, right, to all these other places. That's right. It was really interesting because most of the time we come back to saying, oh, so we're all Martians, right? Because somehow it's cooler to be a Martian, then to be an Earthling. I don't know why. Right.

But there it's kind of really interesting because if you look at the planets and moons in our solar system, and you mentioned Ancelotus and your roper and Titan the three other worlds, in addition to Mars, where we're trying to figure out if it could be life, then basically the Earth had the best conditions for the longest, because liquid water on the surface, we don't know of any life that doesn't use liquid water, was the longest around here on the Earth. And so by taking that, we just really hope that any Martian life we find is not a copy of Earth because A, it could have been like thrown out. And so then was it a second Genesis? And the second problem we have, and we're thinking about this very strongly, especially for icy moons, where we haven't landed

yet, right? So Ancelotus and Eurper and Titan, we haven't actually landed on yet, is that on Mars, we could have brought hitchhikers on early emissions. And then if those by you, Ayota could survive in Martian conditions, right? Some of them are extremely sturdy. What about if to survive and strive, and if we scoop our Martian life, it looks exactly like home. What does it mean? Does it mean we are Martian?

Does it mean they are earthlings? Or does it mean life just evolve similarly, right? And so that's going to be a beautiful puzzle that we hopefully don't have to solve because what we're really hoping for in the solar system is life that is kind of different, different amino acids or a different kind of DNA structure, or a different kind of cell structure. That's what we're really hoping to find in our search for life in the solar system. But taking all the stuff we know, we now extrapolating out. Because the big problem we have for planets that circle other stars is that we can't get there.

We can drill through the ice and check if there's actually life in the oceans, like, for example, an Enceladist or Europa. that also luckily have gaseurs, so there's water spewing out. So maybe we don't have to land and have much an easier way not to contaminate anything by just flying through that spew of water that comes out. But for other planets, we'll have to use our Earth, the only place that we know life is at, to basically get as much information as possible of what to look for.

And thus, Hudson Bay, all these weird kind of microbes that I usually don't think about, Yellowstone National Park, all this hot loving microbes, like, you know, that I also usually don't think about when I think about life. And trying to put a color catalog of life, it's what I call it, together, so that we know what our telescopes could pick up if life that exists on Earth, but in a nation environment, we're the dominant life somewhere else. And just think about algae blooms, just think about a hugely ocean cover with red algae or green algae, and this is when you can envision what I'm trying to talk about. and what kind of models I'm developing for us not to miss science of life,

just because we might be a little bit too focused on what we see outside when we look. Got it. You said this place was steps from the water. We just haven't found the steps yet. How much did we save? Enough. Enough to get lost. Or you could book a stay with Hilton.

Welcome to your ocean front room. Just steps from the water. The Hilton sale is on now. book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected. When you want savings, not surprises. It matters where you stay. Hilton, for the stay. Okay, I want to get to our nerding out session.

You promise me the nerdiest, most fun set of lecture slides that show me what I would have missed if I could go back in time, even though I'm older than you, by a lot. But I'd have you as my professor. Anyway, I don't care. We're not going to violate space-time causality, as Carl's saying. and did, as Ellie did, Arroway in contact. But anyway, I want to get to your nerding out because I love that. But first, I want to ask you one more emotional question.

This is something I think about, you don't have to answer if you don't want to answer it. But if you could be guaranteed in your career, let's say the end of your career, which hopefully will be another 60 years or more, but let's say you get to the end of the career and then you discover slime mold on an exoplanet and you are responsible for it, You and your team, and you've discovered the first ever evidence of life in the universe. And it comes with a little note, and it says, we're the only form of life that ever will be found in the entire galaxy, let's say, okay? Or you could have one of your great, great, great, great, great, grand PhD students discover technological life a thousand years from them. Which do you take?

Satisfaction in your lifetime of discovering the only life, primacy. of slime mold that I have in my refrigerator, or would you settle for the knowledge that a thousand years from now will make contact with a super advanced alien civilization? Is that my question? I can't pick both? No. No, no, no, no. Can the smile slime mode be like technology get advanced?

All good. Athletic Green sponsor of the podcast? No, I'm just kidding. It's not there no letters. I do have to say, is if we just find life anywhere. It doesn't have to be me. Can be my grand, grand, grand, grand. PhDs, whatever form of life. If we find it once, we know it has to be everywhere. Because we are

so crappy in finding it. Our telescope, yes, they are big, they're beautiful, they're bringing amazing images down, but they are not a perfect tool or not even a great tool yet to find these tiny, tiny signals for us to find life in the universe. And so if we find life just once somewhere else that is not Earth's life that we brought as a hitchiker, then the universe, must be teeming with life. And that is basically what I'm hoping for. And yeah, at the end of my life, can it, can I be selfish at the end of my life? I think, I actually think if we just find slime mold, that's going to be the step that everybody's going to jump on. And it's not going to take us a thousand years to find the other slime molds and the other technical civilized stations if we can find the first

signs of life because then it's going to be all out because students are already so excited about this research about that we could be a generation where you find out if we're alone in the universe that there's so many brilliant minds that will have so many better ideas than I could ever have that will just take it and move forward. Wow. And find stuff. Yeah, we will with all the tools and technology that your team is working so diligently on. So now we've come to the nerding out session. So I'd like to ask you to set up the PowerPoint, share the screen, and Just a reminder, you can win a meteorite, guaranteed win a meteorite if you join my mailing list and use it.edu email address. And that's because I'm trying to really be forceful in my attempts

to communicate with students. And my target audience, my target demographic in some ways are students of all ages, but especially young people and helping them kind of navigate what I call the academic hunger games, which unfortunately is too common these days. And it starts with the hunger games of getting rejected by Cornell. I'm not going to mention that. So, Lisa, you've got your street. I've never heard that. And you know what?

If you want to do a PhD with me, just let me know. Actually, yeah, that would be pretty tempting. Yeah, I'd have to leave, you know, La Jolla, which is, which is quite an attractive place. We have some life forms here, too, which is. I was about to say you'd get to do snowman right now instead of being in the warmth where you just don't know what kind of season. It's so brutal. I just envy you with that, that brinketland. risk cold air that drove my mother crazy and forced her to move to the far south regions of New

York State on Long Island. So Lisa, we see your screen. It's showing me the presenter view instead of the, there we go, perfect. Awesome. Okay, the screen is yours. Let the nerding begin. This is a treat. Everybody out there, leave a thumbs up. If you love what you're learning about, and Lisa's unique brand of brilliance combined with just irrepressible enthusiasm. So Lisa, Lisa, it away. Thanks a lot. So I wanted to just bring home just a couple of points in our search for other Earth. And yes, we found lots of different planets, but what I'm most interested in is the one that could potentially be like ours, and that's, of course, ours that you see on the slide. But if you keep going, right, so hours or a habitable planet doesn't have to at all look at

hours, right? It hasn't have to be a carbon copy. And so let's see. see what we found. The first thing that I did want to point out, if you want any more information, the Carl Sagan Institute at Cornell has about 40 faculty from about 15 departments, and it's interdisciplinary. So we have biologists, we have chemists, we have engineers, we have science communicators, we have arts and science, arts and science, so arts and science engineering, and we have bio, and we have like performing arts, everything also how to communicate this amazing excitement because there's so many people who want to be part of this search and this finding life and for sharing it. As Brian was saying before, you know, this is only possible because

everyone is interested in, even if you don't work on us, right? If you were interested in our space in the universe, this gets us going with your insidious and with your question on the street and, you know, with the textiles that we spend on telescopes, like the huge James Webb Space Telescope that we just launched. And so if you want a deep dive, I'll give you a little deep dive, but if you want a real deep dive, it's like there's an annual review I wrote about this topic, how to characterize habitable worlds and science of life. And so, yes, annual reviews are pretty amazing because they have scientists who spend like

about half a year, I spent half a year and hundreds of papers, summarize the topic for you. And I strongly believe in that the best way to teach or to think about, something, is to try to show you the way I see things. Because hundreds and thousands of papers have gotten me to the point where I am. And the fastest way for me to learn from somebody else is if they do the same. It is to show me the way they see, the way they see the field, the way that they think about it. And so I tried to do this in the review. So, you know, great. Just for young people that might not be familiar, this is the most prestigious, one of the most prestigious outlets for astronomers to communicate, not necessarily, as Lisa is saying, original research, although

she has some of her own research in this article, but it's the compendium of the brilliance of the field, the hive mind of the field. And this journal in this particular journal is the highest of possible impacts on the field. So thank you for this. I'll put a link to it in the show notes below. Thank you. But so if you want to dive in, that's a good place to get started. And there's lots of links to where you can go from there. But where are we? We have more than 5,000 worlds that circle other stars, right? So from 1995, when they found the first one around a sun-like star, and that's the Nobel Prize, of course, for Michelle Major and Dediate Kelos, who did that, what was amazing and super hard to do, we have more than 5,000's known world around other stars.

And that's incredible, because what that does, it gets you from looking at one object and thinking about it to an ensemble. And in an ensemble, you can see, patterns. And those patterns tell you something about where these planets come from, how they are made, what the evolution of a planet is. This is how we figured out how the stars work and live, like how our sun actually was born and is going to die. And now we want to do this for planets as well, trying to get a glimpse of the diversity. And I promise Brian to nerd out a little bit. So basically, what you see here, and don't worry if you don't get the whole scoop, I'm just going to point out the most interesting things here. So what do you see on this axis is the radius of the planets.

Okay, that's the y-axis goes up. And then on the right, on the bottom, the x-axis, the sign that goes to the right, is the periods and days. And then I've marked the size of Mars, Earth, Neptune, and Jupiter here. Well, what do you see? We see two blobs, right? That's really the most important thing here. And one blob is up at Jupiter or even higher and at very short periods. What that means is the period I've shown you here is the year on that planet. We have 365 days. So a year on Earth is 365 days, right? So if you go to the period of one day, what that means is extremely hot because you're so

close to the star. So you see this blob. So there seem to be like huge fluffy Jupiter. That's the first ones we actually found very close to their star. And there's a second blob. where you see that most of the planets we found are actually in size between Earth and Neptune. So that's weird because Earth is the biggest rocky planet we have and Neptune is the smallest, gaseous one. But it seems to be that most of the planets there are are actually bigger than Earth,

smaller than Neptunes. And now the guessing game is on. Are there rocks like yours called superers or are there mini-neptune? And the color coding is just how hot their star is because it's just easier to find planets around small stars. Because the same size planet around a smaller star makes a bigger signal. That's as easy as it is. And if it is fast in going around the star makes a bigger signal than if it takes hundreds of days. This is why this whole pattern is kind of a bit constrained by observations too. So that we haven't found an Earth analog and that we have less than less planets when you go down and to the right here, so it's between Earth and Mars and for higher periods, is just

observational. It's not that they don't exist. But the two blobs that you see are actually, especially if you cut off the period around 100 or 30 days, these are real. They are really in the data. And so apparently the most common planet in the universe is one we don't have in our system. You know, who knew? Who could have even guessed? And so if I throw this around and I give you the radius and the mass. You know, if you have a radius and if you have mass, you can get to the mean density of an object. So what I mean by that?

What I mean by that is if you have the Earth and you throw it in water, it will sink. If you have Saturn, the one with the rings, and you throw it in water, it would actually swim because the mean density of Saturn is lighter than water. So gas planets are really completely different than rocky planets. And what we find, again here, what do you see is that we have blobs. So big blobs, big mass, big radius.

And then we have a small blob here. And this small blob is actually where the rocky planets come in. That I'll show you in a minute. Now, this one is one of the tricky slides that you'll see. So bear with me for a minute. And if not, just forget about this one. I told you about the mean density. If I have radius and mass, I can tell you if something is a

rock, blue, right, like the earth that will sink in the water, or a gas planet like a Saturn, because I mean density is different. Another way to think about it is, I can tell you if this thing is made out of rock or marshmallows. That usually gets the attention of my students because they were like, what? Pl planets are made out of marshmallows? I was like, no, but I was just checking if you're awake, right? They have made up the gases one are made out of hydrogen and helium, so completely different than the rocks. But you have to be a little bit careful because mean density of marshmallows is pretty close to that. And I learned that by looking it up.

And so think about this hot exoplanets as smores. But because they're hot, they're close to the star, but smores made off hydrogen and helium, way less tasty to eat. That's all I'm going to say about these hot, big planets because I'm really interesting in the small ones. And so what you see- I'm getting hungry.

Me too. What do you see here is lines. The dots you see here all the planets we found. The purple ones are the one in our solar system, so forget about the purple ones. V and E is Venus and Earth here on the left side. And if you want more information in the review, that's all spelled out. But basically, you can say if this planet is made out of just iron, that's the F-E on the bottom 100%, this is where it should be. And then you can say if the planet were Earth-like, that's the green line, this is where it should lie. This is where we should find it in terms of mass and

radius. And what I find fascinating is that we actually found already a lot of planets that are, from all we know, similar to Earth's composition. But of course, not for all of those, we can actually get mass and radius, because radius is when the planet goes between us and the star, so the light from the star dims a little bit, and we can figure out how big the planet must be. And then the mass we get if actually the star wobbles because the planet tucks on it. But that's a really hard measurement. And we use big telescopes from the ground to do it. So first order, if something is smaller than two Earth's radii, roughly, it's a rock.

So when you hear something in the news about a cool new planet in the Hablo's zone, first check, is it above or below two Earth radii? If it's more than double the size of our own planet, it's most likely a gas blob. still interesting, but not as interesting as if we were a rock, at least to me. Because these gas blops. I'm sorry to interrupt, Lisa, but just to go back to the iron part. So when you receive these meteorites, if you're so lucky to win one, if you don't have an EDU email list, or if you have one, you'll win one, they're mostly iron. And you'll get the spectrum, and I've done x-ray fluorescent spectroscopy on them, and, you know,

90%, 87% iron. and then the rest are pretty heavy minerals as well, metals as well, that are magnetic. And so one of the tests I ask the students to do or receive them is to play around with these and magnets because you'll be doing basically the experiment that shows that they can't be pure, that these plants can't be pure iron, but they have to have some amount of iron. And iron is one of the most abundant elements, of course, in the galaxy. So just wanted to point that out that you'll actually receive from Lisa's theoretical background, you'll actually receive some experimental hardware to play around with.

And the best thing is to have experimental hardware, like something in your hand where like, oh, my God, that could make out planets. Because all these tiny pieces that Brian is talking about, actually in the beginning of the solar system smashed into each other and made bigger and bigger and bigger pieces until they formed the Earth and the other planets, depending on how far away from the star they were. They grabbed more gas than ice.

and if they were close to the star where it's really hot, they're mostly rocky. And so here you see how that turns out. The picture you see the big one is Jupiter, and you see an incredible amount of weather patterns on it. The small one, of course, is a rock, our own Earth. But so just to get a feeling how different these planets are. And so where should we look, right? I showed you all these dots, I showed you all those points. I said we have 5,000 planets.

Well, if you want to find life, where do you look? And so I was thinking about making this an interactive thing with Brian, but I don't think I'm going to put him on the spot too much. But thinking about it, you close to the star, it's hot. You're further away from the star, it's cooler, right? So orbital distance. You have a super hot planet, a lava world where everything melts. Then you have a planet like Venus that lost all its water,

and then you get to the Earth habitat. And so we've defined something that's called a habitable zone. That's where surface water or water could be liquid on a surface on a rocky planet like the Earth. It's a handful. But basically for us to find life somewhere else, it shouldn't be under a huge layer of ice. Because that makes the big problems in our solar system, right? So for these icy moons with a big ice layer, Anceladus and Europa, we have to go there and either

drill through the ice. or fly through the geisha, the things that they spew out to figure out what's going on in the ocean, Berlin. And if you have a star very, very far away, that's not going to work because we can't get there. So the only thing we have is light. But light and matter interact. So when light hits a molecule or an atom, when light hits a molecule in the atmosphere of a planet, it starts to swing and rotate. And that leaves a telltale sign in the light that I receive from a telescope. there's something missing.

And that missing tells me what the atmosphere of the planet is made out of. That's really what astronomers do most of the time. We look for missing stuff to figure out what chemicals the whole universe is made out of. And so we know how bright the star is. And then we know at what distance

it's nice and warm. At what distance it's way too hot. So you would actually melt the rock on the surface. Yes, there are planets out there. They would have a lot of covered oceans. Not the ones we want to go visit, but there are out there from what we find. And then if you're too far away from your star,

you start to get frozen over. And then so far away, like us to the next star over, so our star, of course, the sun is eight light minutes away. But the next star over after that is about four light years away. So we can get there. Is that Ithaca on the right? Is that Ithaca? That's what I'm about to say.

But no, not all of it is frozen over. Even so we are still a little bit in the half room. but basically if you want to think about it plus minus 70% of the energy we get here on the earth is what you're looking for to hopefully have oceans and rivers glistering so i have a lot of more in-depth thing do you really want to go and actually nerd out or do you want to come back and just talk about what we'll be looking for piece by piece well i definitely want to get to the questions for the audience so um maybe with that We'll postpone some of the nerding for their questions at the end.

That sounds perfect because I think, if you allow me, what I will do, I'll just go to the fun part. So, Earth, of course, let me be five more minutes. So Earth, of course, has changed, right? And I told you about all these different things. And, you know, the habitable zone, all of that depends, what kind of gases and volcanoes you have. And, you know, what can give you all links to that?

But if you go just a little further, think about that Earth would actually not be recognizable if you were a time travel. Like, I would love to go with Doctor Who. You gave me like finding Slimele. I really want to be on Dr. Hood's tardigrant, that Tardis and just go and actually explore the universe like they do. And they never have to worry about breathing. Because, of course, the Earth, not just the surface, you know, all the content,

moving and so on, but also the air changed, but we can use that. So we know that the Earth's changed. We know the surface changed. We know what was on the surface changed. And about 750 million years ago, there was no green land plants. It started to be barren. So it becomes really, really interesting to think about if you were a time travel, you wouldn't recognize our planet. There will be no more Himalayas, Alps, anything, because the continents have shifted. there's no more green. The only thing that could save you, maybe, is if you know your constellations,

if you know the stars and you're like, I don't know what planet this is, but at least the sky looks familiar. And so what we did here, and I thought that might be a fun thing to talk about, is when I was, we were talking about Hudson Bay, we were talking about Yellowstone National Park, all these beautiful colors is different kinds of life

that are just not dominant here. but we basically bag, boarded and steeled, is what I call it. So we ask everybody if they had some kind of biota that they wanted to send us, and we could just basically measure what they looked like, what it would look like to our telescope, because that's something biologists don't do because they don't need that. And then astronomers don't have any biota because we don't do that. So we have this really interesting mix in my research team

and also the Kalsaken Institute. We actually have a lab where we grow stuff. You know, we is the royal we because I kill most stuff I grow. So I have an amazing team that grow stuff for me. And also the astronomy department was informing me that because apparently Carl Sagan sent the building on fire at one point, we're not doing these experiments in our astronomy department anymore. I'd rather find somebody who has a biolab with all the equipment.

And so we're doing that. But it's just this different vibrant colors, right? I don't know what kind of life could come out of it. If you and me would have like red skin or green skin or, you know, you know, know, if dinosaurs will be walking around with all different kinds of colors or something completely different. But we know that if part of the planet were covered with this different kind of life, we can spot it in our telescopes. And this is one of the fun ones that we had for the astrobiology, is a magazine that we use. And we got the cover for this work of one of my students, Ligierke-Ello.

And so basically, how would you use that? Think about a frozen world. We're going back to when you were saying you were actually seeing only penguins, a lot of life can actually thrive in ice. And it can color that ice. It's one of the biggest problems we actually, or one of the problems we actually have with climate change. Because if the ice gets colored by biota, that can all of a sudden strive because it's warm, the reflectivity of the ice will go down and it will warm faster. And so in a way, it's pretty funny how, again, these different researchers come together because I want to know about this. So to find, on another planet somewhere else in my telescope.

And people on the Earth want to know about this to figure out how to help or mitigate climate change. And so one last thing that Brian was allowing me to do is to do another fun aspect. So we have, where are we looking? We found 5,000 planets. Where are we looking? What's this habitable sound, right? Well, determined by we cannot look through ice. It's something that's so far away that we can get there.

But once you think about the other. signatures of life that you could look in your telescope. One thing that's that jumped out at me was the question is like, so who could see us? If they were alive, and you know, we have talked about this, there might be zero or there might be billions, right? If they were life and they had just our level of technology. So we find most of the planets because the star dims a little bit when the planet goes between us and the hot stellar surface of the star. The star looks as if it was less bright. still the same brightness, we just don't see all of the surface. And so then we said, well, how many stars could see us that way?

And it turns out, this was with a colleague of mine, Jamie Farthier, at an American Museum of Natural History. Turns out you have about 2,000 stars that right now within 300 light years, that's not much, could see us. And the fun part about it was where are we the aliens? Right. They are actually 75 of those where also the radio waves would have already passed by them. So they couldn't just see the dimming of our star.

They could also listen to really bad music and television from a while ago. You know, it's getting better with time. But, you know, I'm a bit biased. Some of those already are known to host plants within this habitable zone I was talking about. And we are observing more and more of this. And one thing that I really liked about this is, there were headlines about this paper. They were so funny.

It was like 2,000 ways Earth has blown its cover. And then there were somebody who was saying, ooh, are you feeling watched? So with that, I can actually give you some relaxation, watched maybe in terms of gases in the atmosphere, but I don't think that anybody can like zoom in all these worlds hundreds of light years away.

But it's kind of interesting to think about that if we could have been discovered, and that gets back to your question, Brian, right? So why is nobody here? Right. Use acid for the solar system, but you can also ask it for wider field, right? If the universe is teeming with life, why do we not find anything? And no UFO sightings can actually stand up, unfortunately, because I'd love there to be signs of life that comes and visits us.

It would shortcast my research, and I wouldn't have to wait until the end of my rear for slime mold or a thousand years for technical advanced. If somebody were landing and saying, hey, we are aliens. That would help me so much, much more than a hard way of trying to find life on other planets. But what's really, really interesting in this is when I ask my students, I say, okay, let's say it's hard to travel or it's actually hard to communicate or, you know, it just costs a lot to communicate. And I have two planets, two planets with signs of life. One is 5,000 years younger than us, and one is 5,000 years older than us. I can only do one in terms of communication or getting to.

Which one should I pick? Yeah. Which one do you pick, Brian? I pick the more advanced one, but... I pick the more advanced one, too. 90% of the people I ask. And so if you turn that around, you know, I love a planet. Earth is my favorite planet.

I adore it. But if the universe is teeming with civilizations, are we really the people you want to come and visit? Because, you know, face it, we had boots on the moon, but we haven't even gotten humans to other planets yet. So in terms of interest, we might not be the most interesting people out there if there's life out there. And so that was just kind of the thing where I wanted to bring it around to what you ask and then we're going to get the questions. Yeah. In case somebody wants some more information, I've got the review. This is basically some thoughts I had.

And then, you know, feel free to email me or ask me on Twitter any questions that you have. But hopefully we'll have some now, right? Yeah, we have a whole bunch now. But I'm going to take the host prerogative and ask the first one. If alien exoplaneteers, exoplanetary biologists at their own, you know, Sagan Center, somewhere distant, distant Lisa, If they haven't JWST, how far out could they spot Tokyo? You know, could Trappist one, which you've had some great involvement with, could they, you know, are they close enough far, too far away to actually use a technology

like a six meter infrared telescope to spot a megacity on Earth? So megacities you actually can do. There's a paper on this and it actually says that you have to be pretty much in our solar system before you can see megacities. But gases that we breathe in and out, oxygen with reducing gas like methane, that basically we cannot explain with anything else but life, that you can see from far, far away. And we showed in our research that you can see that for about two billion years in Earth's history,

because of course before there was not much oxygen, so you couldn't see that. And if life makes just CO2 in methane, then you have the problem that you can get that from volcanoes too. So you need unique signatures, extraordinary evidence for extraordinary discoveries, as Carl Sagan said. And so you can go pretty far out, but the question is always, as you know in science, and your viewers might not know this, but it always is the question how much time do we get? Because the James Webb is an amazing instrument. And it has completely changed how we can see the universe. The problem is it hasn't just changed it for exoplanets because there are these pesky people who want to know something about the early universe or black holes or galaxy evolution who do not understand that we just want to use all the time on exoplanets. That was, of course, a joke.

I think for me, because I love exoplanets, this is the most important thing. There's so many other interesting things that other scientists want to do and they are amazing. So we don't get to commenter the James Webb Space Telescope just to find life on other planets unfortunately. So if an alien civilization could, they could be pretty far out actually

and still find life on our planet. Very good. Okay, first question that we have here comes from longtime friend of the channel, Jimmy Jassy. He wants to know your views on the origin of life. And he has a further sub-comment about Darwin and you can, we don't have to get into that, Jimmy.

But what do you think about the origin of life? As you said, you know, if we find Martians and they're really Earthlings or maybe we're Earthlings and they're Martians, that just, you know, defers the question maybe of how life originated. It doesn't solve the question of how life originated. What are your thoughts? I know it's not exactly your field of research, but you are, you know, this pan-dynamic institute director.

So what are the current leading thoughts on origin of life from your perspective as an astrophysicist? So what's really interesting, and I'm with you there, you know, it's like, how do we not know how life started on the earth? How is that even possible, right? When I started to do the evolution of earth, you know, my models on the evolution of Earth, I just thought we knew so much more than we do. And it's fair, right? It's hard to know because the further you go back, the less love records you have, the less fossils you have. And then life actually starts to have nothing to actually contain in those fossil records because there were no more bones, no more feathers. it becomes squishy and so it's hard to actually find it.

But so the major theories right now is that you could have kind of three regions where life should have evolved. It could have evolved. One is on the bottom of the ocean where we have something that's called black and white smokers where it's super, super cold, but there are regions where like super hot water with a lot of sulfur gets spewn out from the ocean floor. And that temperature gradient actually allows for a chemical gradient. And the chemical gradient is key to try to get some kind of chemicals together to make a cell-like structure, to make DNA-like structure.

We think it's RNA and then DNA. The second one, that's kind of the running winner for now, but, you know, not winner. It's just like a lot of people believe that that would be the easiest way to do it. Is a shallow water hypothesis? That just means you have a shallow pond. There's chemistry in the water, right? It gets hot. You evaporates some of the water.

it gets more concentrated. And then on the bottom of that pond, if it's like clay or something, there are some things that just cling together and form the first kind of structures. Cells, RNA, this is how you start to go. And then the third one, that's a little bit less favorite, is that you could do it in ice. Because when you freeze something, you also concentrate the chemistry in the resulting water. If there's just a little bit of water left, most of it is actually highly concentrated chemistry. and then you could melt it a bit more and again make it more versatile.

But the problem is that if you have the huge ocean, you don't concentrate the chemistry enough to get life started. So you either have to have shallow waters, bottom off the ocean with a temperature gradient and chemistry gradient coming out, or maybe in ice where you actually freeze and de-freeze the water. Very good, very good. So there's another question coming in from a long time, friend of the channel, Andy Oates, and he's asking about how does the equation change with the discovery of exo moons and even of asteroids with moon moons. But I want to, well, first get your take on that, and then I want to ask you about a Cornell alumnus passed away sadly last year,

Frank Drake and his eponymous equation. But first, does the discovery that there are, in fact, exomones, does that raise or lower the probability of finding life, given that the moon, an Earth's moon, is responsible for our tidal phenomena and the black smokers and stuff are related tectonic activity. Tidal activity also seems to play a role in these stromatolites that extremophiles have been found in anyway, Lisa, what does the discovery of exo moons do for the chances of life of any kind and maybe even of technological life's probability as a theorist? So one, we haven't found an exhumoon yet, but we're desperately looking.

There's some indications that there could be some, but there's no definitive exhumun yet. But I said billions of billions, a little cheeky's leave, because of course, calls second's book billions and billions, but we are very conservative. You know, one out of five stars has a planet at the right distance, small enough to be a rock within this habitable zone. But then there could be billions more of movements. out there that could provide around gas giants places for life like, you know, Enceladus and Europa do and Titan hopefully do in our solosite. So there are so many other options that we

haven't even explored yet that could also give us environments where life could strive. And so I kind of really like our chances. And so when we go back to the second point on this is do you need a moon to be habitable? There we come into something that I find fascinating and that I had to grow out of because it is so easy to just look around. It's like, oh, yellow sun. So life needs a yellow sun. Oh, moon. So life needs a moon, right? And yes, the moon stabilizes our season and there's lots of other things going on that the moon does for us and for life on the earth. But it is because life on the earth developed with a moon, right? It didn't develop because a moon from everything we know. But it, of course, used everything in its environment to strive. And so if you take the moon

way in a planetary scenario. We probably, the planet doesn't have a problem. That life on it probably doesn't have a problem because it basically evolves without a planet having, without a moon being there. And when you look at our solar system, it's so interesting why we have a moon in the first place, right? Well, Venus doesn't have one. Mars has two tiny, caught things and Mercury doesn't have one. And a big question that people are trying to figure out is that maybe because of the huge impact, there was a Mars-sized object that hid the Earth and then threw part of it out to make a moon, first a ring and that formed a moon. Maybe that got tectonic kickstarting it. And maybe that helped. But on the other hand, Mars should have had tectonic initially too. And it never went through this

collision. So it's going to be super important to find other planets and get our info from there from the patterns. And when you were talking about life before, it's like, how can we figure out, well, I've started on the earth. Well, think about it this way. If you find lots of earths that are frozen and have always been frozen and they show sign of life, then a cold start is likely. If you find lots of earth that are hot and only they show kind of light, then a hot start is likely. And so we basically piece together what happened in our own planet and how life started from the other places where we get information from, as scientists always do. Very good. So long-term, friend of mine has at least half his name shared with the namesake of the Carl Sagan Center,

and that's Fred Carl asking, do we have a carbon life form bias? In other words, do we sort of have this predisposition that life must have evolved elsewhere in the universe as it did on Earth in terms of primarily based on, or entirely based on carbon and so-called organic chemistry? Is that a fair bias that we should continue to hold on to, or should we put it in the dust bin, a speck of dust in history? Yes, we do have a bias. However, it's quite interesting because if you look at the Earth, like, for example, silicate sinks that people talk about,

you know, instead of carbon that you could use. We have that on the Earth. There's actually more silicate on the Earth than there's carbon. It's just locked in rocks. And the problem is it doesn't make gases very easily. either. You have to go actually very high in temperature to have a silicate SIO2, for example. And so the question really comes down to under what condition is carbon and water your best bet? And this habitable cell that we have defined, right, is basically for that best bet.

The solvent being water and then the backbone probably being carbon. But if you just think about a Titan, for example, we hope there could be life. This is why we're sending a super cool quadcopter. We're sending a quadcopter to another moon in our solacea. I just think that's super cool. And part of the Cal Sagan Institute is working on that. And I just get updates.

And I'm like, so cool, can I fly it? Dave won't let me play it. But, you know. After what happened in the lab with that explosion and Carl Sagan. But the key point is for Titan, it's too far out. It's a moon of Saturn. Yes. And so it's too cold.

there's no liquid water on the surface. But there are lakes of ethanol and methane. So different solvent could absolutely be a base for life. And so people are looking into how you could get similar kind of life started. How could you make a cell structure with a different kind of solvent? How could you make life backbone with something that's not carbon? But there's really a lot of good reasons for carbon A. It's one of the most abundant things in the universe, carbon, hydrogen,

and oxygen. And also, life on the earth showed that it was incredibly good at using what's ever around. And it used carbon. So in other places where carbon is incredibly abundant, it's kind of hard to imagine why it would just say, ooh, not using that one, use something else, except if you bring in temperature. If you bring in temperature, then the solvents need to change. Because other than that, ice is just going to be block of ice, right? So water is going to be block of ice. And so there's lots of fascinating things. And so, yeah, absolutely, we have a carbon bias because we can make life in the lab yet. If we could make life in the lab, we could just throw, you know, something else in inside

of carbon and try to figure it out. And a friend of mine at Harvard was just so funny because I asked him, so what about life in the lab? How hard is it, right? And they were like, well, it's the most terrible PhD project because you need something to publish in three years, right? It's just like, it could be tomorrow. Three years.

Oh, my God. Why would you want the square root of the number of years that I have my graduate students? Just kidding, I don't do that. But the interesting thing about this is just to say that you don't know how long you have. Let's say this is the bath or how life could get started, right? So when do you change the parameters? Did life need a thousand years? Did it need five minutes to get the initial thing started?

If you just change it a little too fast, you've missed it, even if the parameters were right. or if you change it too slow, it's going to take you thousands of years to figure it out. So trying to make life in the lab is fascinating and incredibly hard to do. But if we could, then we could actually work on our carbon bias. For now, we can only look for stuff that we know makes life. Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals

because we're built for what you're building. Fit for your ambition for Citizens Bank. Lisa, do you have time for a few more questions? Oh, absolutely. Sorry, and I'm going to try to be shorter. No, no, no. It's so fascinating. But there's just so many questions. You can leave your question in the live chat or in the comment of the video afterwards. I'll send the link to Lisa and she'll maybe troll the comments section and say we have to get a better host into the impossible podcast.

So I'm going to ask you a question that is kind of aligned with my curmudgeonly side. And that comes from Sam Adams, founder of this country. and he shares a view that I find somewhat persuasive. Here's what he says. He's not actually asking a question, but he's making a statement. He says only 10% of the stars in the galaxy are like our sun. Jupiter and Saturn's orbits are kind of act like vacuum cleaners. They scoop up dangerous comets and asteroids.

Luckily not the green comet, which you can see tonight. We'll have some information about that on our Twitter feeds. But they kind of act as bodyguards for the earth protecting the earth. The moon distance to the earth of our moon and only a single moon is quite favorable. Most stars are binary stars in the galaxy. I think that's correct. Anyway, he's basically saying there is no one else in the galaxy, let alone, you know, advanced life form, not even slime mold. There's too many terms in the Drake equation, so to speak, that are inhospitable to life.

And then he adds on echoing some of my curmudgeonliness. He says, be glad there's no one else in our galaxy because it would be a disaster if we did meet them. How do you react to these pessimists, Lisa? You're such a cheerful person. What do you do on your down days? Do you ever think, oh, my God, these Sam Adams guys are right? You know, there's just too many variables in the Drake equation that aren't really captured and the kind of nuisance variables. But those are the most important things, the plus or minus 50%.

I like to say the interesting thing of the Drake equation is not the equation solution. It's the error bars that you put on it because they can be anywhere from zero to 100% of the value. So anyway, how do you react to this rare earth, as Donald Brownlee and others have called it? There's so many things that are so improbable. There's really zero chance. Sorry to break it to you at the Carl Sagan Institute, but maybe you'll become a cosmologist and you'll get your second PhD. How do you react, Lisa? I think it's great to bring this up because, you know, when I talk about it.

this, you could be like, oh, she's like optimistic about all these things and so on. So let me just unpack a couple of these things. And this is where we're saying that sometimes it's so hard for us not to just see or see the things that are around us, because of course, that's where we get the patterns from, right? So this is why when I was talking about, you know, we need to find different kinds of life or look, at least look for them. But let me unpack this just to a little. So Jupiter Saturn, let's just talk about, you know, what hits the Earth. It's like, it's actually there's a really interesting paper that I like and it's just like I remember the title because it's just such a cool title, Jupiter friend or foe. Because when you look into it, Jupiter

actually does as much harm as it saves us because yes, it collects a lot of these pieces that would be throwing onto the earth. But it's also the reason, because of its huge gravity, that those pieces keep starting to flow in the first place, right? So it's kind of, if you look at it in detail, it's kind of a wash. And then the question is, what would have, happen if there would have been more impacts, right? Maybe impacts, that's actually very interesting in biology, maybe impacts are actually the thing that get life to evolve further. Remember, there were these extinctions event in life's history, and after that, life actually started to blossom. You know, would it have ever developed from slime mold if we never would have had this pressure,

this environmental pressure for it to evolve, right? So that's that part. And then the moon part, I completely go, you know, we have this moon, and it seems to be such a beautiful, special thing. And I love our moon, not even a question. Me too. But think about it this way. If you go back in Earth's history, the moon initially was very close to us. We know that because the moon is still moving away from us. So what that means, we can calculate that, is the Earth must have had a much faster rotation when it was young.

So about eight hours is what we expect it to be, have been early. So what that now tells you is the rotation rate of the planet cannot make much of a difference because other than that, life wouldn't have started here, right? So the 24 hours is actually quite late in terms of rotation rate. And by the way, you're gaining like nanoseconds per year. So the day is getting tomorrow is just a tiny bit longer than today. If you're looking for the extra hour in your day, I'm going to have to look for a while, but getting better.

And so a lot of things that seem very special. to us are actually just because we see the end results of all of it. And just think about if you had an ocean, right? Even if you have lots of impacts, if you had weird seasons, life on the bottom of the ocean wouldn't care. It wouldn't even care about the composition of the air, right? Because you wouldn't need that composition of the air. Yes, maybe it would never get on land if there were land because there's some kind of radiation on the surface of the planet and so on. And the second thing that I wanted to mention what was really surprising, in a way, we got super lucky. You go completely right, there are not many yellow stars like the sun.

The yellow star is a very standard star, but it's not the most abundant one. The most abundant one is tiny, small, not so massive, red suns. So when you look around, somehow, we don't know why, Mother Nature, if you want, made much more rocky planets around these small stars. There is a component of how does make sense. because the disk that forms around the star to make these planets about 1% of the star's mass doesn't have so much stuff.

So you can make rocks, rocky planets, the small ones, but you can't make big Jupiters because you don't have enough stuff to do it. And so what we find is these small stars that are most abundant in the universe actually have most rocky planets within this habitable zone. And so we hadn't even talked about Trappist 1,

one of the really interesting, fascinating planets red sun with seven earth-sized planet and four of them within the Habitable Zone boundary. So there could be four Earth there. They could just be no life whatsoever, right? But this is, of course, one of the high priority targets we have for James Webb. And we have some super interesting information that I can't tell you because I'm not the first author, but it would come out. And so what I'm just saying is that I love the question because it allows you to unpack our biases. And I had these biases absolutely the same when I started out. And then I talk with

biologists and geologists more. And then you figure out what you think is desperately needed for life is not what life needs to get started or even evolve. So this rare earth is maybe also born in little bit in the hope that we might be unique. But, you know, if it turns out not to work out, Brian, I'll take you up on your PhD. That's right. The big. beauty is there's never a shortage of things to learn about. Okay, we have a lot more questions than we have time for, but let's keep going with a couple more. A question coming from, again, from Andy Oates, who really should go and do a PhD with Lisa, does Lisa think a binary planetary system in the habitable zone or green zone, as he's calling it, has a better chance of showing advanced

evolutionary processes? In other words, does your location in the habitable zone too close, too far, still in the Goldilac zone, but nevertheless, does that in a binary with a multiple planetary system, does that increase chances for advanced life forms, or does that have no effect? Thanks for the question, because I was curious about that a couple of years ago, and so I actually figured out where the Hadril zone is for a binary star. And of course, you know, I'm also a Star Wars fan in a certain point, and so I wanted to know if Tatween could be real, right? That's right. We actually found planets around four stars, so Tatooine is kind of not a certain. visionary as you might think. So science that's actually overtaken sci-fi. What is amazing. I love it.

I love sci-fi. I love the connection. So don't take this with a grain of salt. But what about the evolution of life, right? So whether you have one or two stars kind of doesn't matter because you will evolve for it, right? Even if you think about it, if the planet most likely, or most of the planets we found around binary systems, actually orbit both stars. And so that is a life light source instead of one on the sky. It's like tattooing, right? You have two stars that give you the light. But it doesn't matter because they go around each other like this.

So you always kind of see both of them. So you always get the same amount of light. And so there shouldn't be any difference between the evolution, if everything else being the same on a binary star planet than another one. But we do know that it's going to be harder to make more planets around binary. because the problem is you start to truncate this disk with two stars, especially if the planet actually orbits one of the two stars that happens to. So if the planet orbits one of the two stars, the other star also has a gravitational pull on this disk from the outside that again truncates

it. So you only have so much stuff that can make planets. But fascinating. And it's kind of harder to find planets that are two stars because there are two stars that you have to get rid of instead of one in terms of signal. So this is why we haven't found as many planets around binary stars as we have around single stars. But most of the stars are in binaries, so 50%, so yes. We luckily found planets around those two. All right.

Now let's go to like yes or no short answer so we can answer everybody's question. Verdi, again, we have some famous, famous channel members here. Verdi is asking, you know, about life. Love the music. That's right. That's right. Although you must be partial to Mozart. I am, but Latraviat is still my favorite. Oh, wow. This is incredible. I love the fact that Mozart and Doppler grew up in the same town,

and they're both have relevance to most astrophysicists. But anyway, he's asking about a magical shield, but I'm going to convert that to a magnetic field. Our magnetic fields, we'll just do short answer. Magnetic fields, are they critical for evolution of any form of life on a planet, a rocky planet? Life on the surface, very likely. Life in the ocean on the bottom, probably not. As long as you have enough air left, that liquid can be liquid, water can be liquid. Got it. Tony Nagy, who asks a lot of Naji, asks a lot of questions. He's a good, good supporter of the channel. Does the Ork Cloud shield us in some way from maybe Avi Loeb's interstellar assaults? Does the Orch Cloud play a role in evolution of habitable planets?

So we don't think so. The really interesting thing is about even the belts in our own solicits and the asteroid and the Kuiper belt, right? Why is there no planet? We don't really know why it didn't form a planet. But the word clad out is, again, a plus minus because it can bring material in to bring, for example, things like water. But it can also lead to huge impacts that could maybe actually deter life or make extinct life. So again, it seems to be like a wash, but because it's so. far out and so far away, we don't know if you just took it away completely what would happen.

Yes. So speaking of the Ord Cloud, you may see one of its former citizens, the green comet, comet discovered, at least in the last 50,000 years ago, since the last 50,000 years, discovered by the Zwicki transient facility at Mount Palomar in San Diego County, not too far from where I am on campus. And that so-called green comet visible tonight with binoculars, as it makes its closest approach to the Earth, 225 million miles away from the Earth. So look for that. Lisa, maybe you'll get a spot at that, that beautiful observatory that you guys have on campus. And it's cold, so we have a Cleonite. It is cold. And you're away from most of the city lights, although Ethica is quite developed.

I don't know if you could spot it from another, from Trappist 7B. How many of those planets Verdi's asking again, are tidily locked orbiting? He's asking about red dwarfs. I think he might be thinking of Jill Tartor's coined Cornelian term, a brown dwarfs. But anyway, how many tidily locked planets might be orbiting around either dim stars or failed stars, brown dwarfs? Do we know about that?

So basically for the red stars, the smallest suns that I was talking about, absolutely. If you're in the harbidable zone, if you're so close, that you get similar energy because the star is smaller, right? So it is not as luminous. To get similar energy that the Earth does, you start to get tightly locked. What means is synchronously locked, one face always facing the star, one face, never facing the star. Like the Moon does to the Earth, basically.

Like the Moon does to the Earth. But the interesting thing is life doesn't need light. Three quarters of life on the Earth actually doesn't do photosynthesis. It doesn't need it. It gets energy from chemistry or some other ways. And so basically, this is again. the bias that we have because the life that's on the surface, right, that's nice and green and does photosynthesis is what we see every day. So it's easy to think that that's the life that's out there.

And so I envision such a world pretty amazingly. You can calculate when they start to get tightly locked and most of them in the hospital zone should be tightly locked because the age of the star is a couple of billion years. Long story short. But thinking about it, you basically have sun forever and then when you want to get tired, you just walk it to dust and dawn. and then you keep walking it. Maybe you have like a biofluorescent life world kind of biota on the other side. I just can imagine an amazing sci-fi movie coming out of this. So, you know, Brian, just keep an eye open on somebody picking this up.

That's right. And you do have a movie that's available on Apple, iTunes and so forth. What's the name of that movie that you appeared in, documentary? That's actually a documentary about the search for life and space and as amazing visual of space. and it came in 3D in the iMix. And so I was like, can I touch it? It's probably as close as I ever going to be to touching the other planets in our solar system

because I don't have any plans to become an astronaut. But yeah, I think it's amazing what we know about the planets of moon and our solar system and now start to learn about planets circling other stars. Oh, wow. Okay, so the next is about from Channel Warhorse, a name I almost chose from one of my children. He's asking about AI life,

But I wonder he's asking if does the existence of advanced AI, what does it tell us about humans and maybe perhaps to infer a little bit more than he's asking, you know, are we more likely to see an AI astronaut, you know, as evidence of extraterrestrial intelligence than a physical UFO hovering over, you know, downtown Ithaca. I think we need a couple more podcasts to unpack that question, right? Fine. If you agree, we'll come back. I would just say it links to what's our future going to be. Because right now we haven't decided yet, right? If all civilizations go the road of AI, right, you don't need any food anymore, you don't need anything. We basically upload ourselves in the clouds. But on the other hand, is this really what we're going to do?

Are we going to just use it to our mentor ourselves, like to help us remember and so on? We haven't made that choice yet. And so it's very hard to guess what a completely different alien is. civilization would make in that kind of choice. And what their lifespans would be compared to ours. If it's a fraction of a second, they probably don't travel the stars. If it's millions of years, then traveling the stars is not such a big deal. Yeah, that's right.

Although someone is asking, why would they even get off their couches when they can just put on an AR headset and just be in the metaverse all day long? Okay. Because there'd be scientists like us, and we could also just sit and binge watch something, but we want to figure new things out. just kind of a feeling inside. And I'm sure everybody has the curiosity about something. Scientists are just incredibly tenacious to figure things out. Right.

The last question that will take before I wrap up with a couple of my own. Comes from Dadsen Worldwide, who asks an interesting question. Can the existence of exoplanets or specific exoplanets tell us anything about the galaxy in which it inhabits? Is there any way to determine, say, from the spectroscopy and the predictor? that you make from a theoretical perspective, could we sort of invert that and learn about, you know, for one thing, you'd learn if there's iron, pure iron planet that that star forming rate in that galaxy must have been quite high and the supernova rate must have been quite high. Can you learn about the galaxy, Lisa, from any of the observations of exoplanets that are cosmological

or galactic physics from exoplanet physics? So that would make my job recruiting much, much easier here. I think you definitely can because a lot of times what's really interesting is when you see a completely other distribution of the exoplanes you found in another galaxy. Let's assume that's what you see, right? Then you'll have to figure out why. And that will have to link with what kind of stars have been made, what the stars are made out of, and that will link back to what happened in that galaxy. We can only do this for close by once, right, because you need light.

Why is that galaxy so different from ours and gives you a different angle? Of course you can observe all the other things like which stars does it have, what's the center of the galaxy and so on, what's the movement. But it gives you a different angle to ask the same question. And the more angles you have to figure out a result, I think the more you can learn. Yeah. Okay. Lisa, you've been such a phenomenal guest.

There's people demanding that you come back for a part two. I know you have a busy and demanding schedule, research and teaching and everything that you do for the cosmos. But I can't help. But echo back to the namesake of the Sagan Institute. And that is Carl Sagan. It looks kind of angry here. I want to get a dollar of you, Lisa. I want to distribute these dolls of you.

But Carl Sagan said famously a book is proof that humans can work magic because you have this article, this piece of incredible intelligence, maybe, or maybe not, if it's this book here, my first book. But at any rate, you have this kind of archive of a human's experience and distilled. And I want to ask you kind of in keeping with that quote that a book is proof that humans can do magic. I want to ask you the kind of update to that. I say a podcast is proof that humans can do magic because now we can save the voice of the actual author, the thinker, the scientist in your case, and we can preserve that forever.

And as Arthur C. Clark said once, he said that any sufficiently advanced technology is indistinguishable from magic. I want to ask you, looking into your crystal ball, what kind of technology or almost incomprehensible technology do we have now, that in the future, people will look back on and say, that was really magical. It could be a discovery. It could be something that you particular have discovered. What fact or what aspect of the universe that you've encountered, maybe even you've discovered, do you find most magical? I think in our lifetime, we found the first planet around another star. And this is a royal way, but it took all of us to get there. And

And that planet for me changed our trajectory as humans, right? And if you think about it in the longer time scale, think about a history book. And maybe there's going to be two epochs, the time before humankind knew that they weren't alone, and hopefully the time after. And I really hope we are just at that brink, because I want to go out at night, look up, see the green comment, absolutely. but I want to look up and say like around that star, there's a planet that could be like ours. And maybe someone is looking up right now, wondering about us too. Lisa, I think you've done more than almost anybody I know to inspire young people and old people like me, to just be fascinated by the actual contributions that a human being, small compared to the size of the cosmos,

as Sagan once said, and yet has infinite worth and infinite capability. I want to thank you so much for coming on The Into the Impossible podcast. I hope the questions didn't get too much. And I hope people connect to you on Twitter. We have links to your Twitter bio down below, the Carl Sagan Institute and follow Lisa as I do for more information. As I said, please do subscribe to my mailing list. If you have a dot edu email address, you'll guarantee to win a meteorite because I want to really promote STEM education to all my students locally and virtually out there in the Metaverse. and I want them to connect with great thinkers.

And I strive to do that on this channel as you have witnessed today with one of my favorite interviews of all time, bucket list interview, made up for me not getting into Cornell. And that's Lisa Calta Dager. Thank you so much, Lisa, and I wish you very successful rest of your day. Enjoy the winter there. I'm just so envious of you. The cross-country skiing you can do there is just so envious.

Thank you so much, Lisa. Thanks so much for having me. Thanks for all the great questions you guys have done. and, you know, think about it and get us help to try to find life in the universe. And, you know, Brian, my offer still stands. If you want another PhD, I can kind of guarantee that we'll exact you in Cornell this time. Okay. Well, we'll see if the donation check clears this time.

Lisa, thank you so much. And I will be seeing you, hopefully this fall and lovely Ithaca, fair Ithaca. We'll go gorge diving together with my kids and you, hopefully. Any sufficiently advanced technology is indistinguishable from magic. So, what do you think? Are Lisa and her colleagues at the precipice of discovering extraterrestrial life? And if they do, how would that change things here on Earth? Let us know your thoughts by posting a review and leaving us a five-star rating.

We love hearing from you. For a chance to win your very own proto-planetary piece of space dust in the form of a meteorite fragment, subscribe to Brian's mailing list at briankeeting.com slash list. And remember, always be curious. All pay off your home, travel for life, drive a Ferrari. In celebration of the world premiere of the Monopoly Big Board Buckslot Machine by Aristocrat Gaming, Yamava Resort and Casino at San Manuel is giving one person a $1.6 million dream package. The biggest prize in Yamava's history. Club Serrano members can earn daily instant prizes and secure a spot in the finale May 29th.

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