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Adam Frank

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2024-12-22

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2024-12-22

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1. “Can all you need is one like right now, it's in any, you know, our understanding of life, we have one example we have n equals one example of life. So that means we could be an accident, right? It could be that we're the only place in the entire universe where this weird thing called life has occurred. Get one more example and now you're done. Because if you have one more example, now you're, you know, even, you know, you don't have to find all the other examples. You just know that it's happened more than once. And now you are, from a Bayesian perspective, you can start thinking like, yeah, yeah, this life is not something that's hard to make.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

2. “92 and 95. 95 to me was really that was the discovery of the first planet orbiting a sun-like star. To me, that was the water, the dam being broken.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

3. “Absolutely foundational for astrobiology, but we should remember that it's not a law of nature, right? It's not something that it's not equals mc squared. And so you can see it being abused in some sense. People, you know, it's generated a trillion papers. Some of those papers are good. I've written some of those and some of those papers are bad. I'm not sure where my paper fits in on those. I'm just saying, you know, one should be careful about what you're using it for. But in terms of understanding the problem that astrobiology faces, this really broke it up in a useful way.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

4. “That's exactly. He gave astrobiology, which wasn't even a term then, a roadmap. Like, okay, you guys go do this, you go do that, you go do that. And it had such far-reaching effect on astrobiology because it did break the problem up in a way that gave useful sort of marching orders for all these different groups. Like, for example, it's because of the Drake equation in some sense that people who are involved in SETI pushed NASA to develop the technologies for planet hunting. There was this amazing meeting in 1978 and 192 meetings, 1978 and 1979 that were driven in some part by the people who were involved in SETI getting NASA together to say, look, okay, look, how, you know, what's the roadmap for us to develop technologies to find planets? So, yeah, so, you know, the Drake equation is.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

5. “We humans, right? Because we're standing, we're staring at the multiple guns pointing at the nuclear war, climate change, AI. So, you know, how long in general does civilizations last? Now, each one of these terms, what was brilliant about what he did was what he was doing was he was quantifying our ignorance, right? By breaking the problem up into these seven sub-problems, he gave astronomers something to do, right? And so, you know, this is always with a new research field. You need a research program, or else you just have a bunch of vague questions. You don't even know really what you're trying to do. So, you know, the star people could figure out how many stars were forming per year. The people were interested in planets could go out and find techniques to discover planets, et cetera, et cetera.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

6. “And like the night before, Drake has to come up with an agenda. How do you come up for an agenda for a meeting on a topic that no one's ever talked about before? The next one is the fraction of planets on which you start to get intelligence. After that, it's the fraction of planets where that intelligence goes on to create a civilization. And then finally, the last term, which is the one that we really care about, is the lifetime. How long you have a civilization? Now, how long does it last?”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

7. “You know, people have various feelings about the Drake equation. It can be abused, but basically it was the story actually is really interesting. So Frank Drake in 1960 does the first ever astrobiological experiment. He gets a radio telescope, points it at a couple of stars, and listens for signals. That was the first time anybody done any experiment about any kind of life in the history of humanity. And he does it, and he's kind of waiting for everybody to make fun of him. Instead, he gets a phone call from the government and says, hey, we want you to do a meeting on interstellar communications, right? So he's like, okay, so they organize a meeting with like just eight people, a young Carl Sagan is going to be there as well.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

8. “Details aside so you can get to the heart of an issue, and that Very useful sometimes. Other times it obfuscates, right? Other times it clouds over actually what you needed to focus on, especially when it comes to complexity.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

9. “Think we're at the point now. So now there may be other kinds of principles that actually because you know coevolution actually has its own not deterministic. You're done with determinism, right? But complex systems have patterns. Complex systems have constraints. And that's actually what we're going to be looking for or constraints on them. And so, you know, and again, nothing against Carter was a brilliant idea, but it just goes to show, you know, there's this great XTC, I'm a theoretical physicist, right? And so I love simplified, give me a simplified model with, you know, a dynamical equation, some initial conditions. I'm very happy. But there's this great XDC comic where like, you know, somebody's working something out on the board. And this physicist is looking over and saying, oh, oh, I just wrote down an equation for that. I solved your problem. Do you guys even have a journal for this? And the subtitle is Why Everybody Hates Physicists. Yeah. So sometimes that approach totally works. Sometimes physicists can be very good at like zooming in on what is important and casting.”

   2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

10. “The creature was so successful, it took over, and there was no space for anybody else to evolve it. So yeah, so the interesting thing about this was seeing how much, once you look at the details of life's history on Earth, how it really shifts you away from this hard steps model. And it shows you that those details, as we were talking about, like do you have to know about the planet? Do you have to know about plate tectonics? Yeah, you're going to have to.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

11. “And the idea of something being a hard steps there's two ways in which something might even appear as a hard step and not be, or actually not be a hard step at all. One is that you see something that has occurred in evolution that has only happened once, right? So let's take the opposite. You see something that's happened multiple times, like wings, lots of examples of wings over lots of different evolutionary lineages. So that's clearly not hot. Making wings is not a hard step. There are certain other things that people say, no, that's a hard step. Oxygen photosynthesis. But they are so, they tend to be so long ago that we've lost all the information. There could be other things in the fossil record that made this innovation, but they're just gone now, so you can't tell. So there's information loss. The other thing is the idea of pulling up the ladder, that somebody, you know, some species makes the innovation, but then it fills the niche and nobody else can do it again. So yeah, it only happened once, but it happened once because based on...”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

12. “Well, there's two things. The first most important one was that the planet and the biosphere have evolved together. That's something that every most biogeophysicists completely accept. And it was the first thing that Carter kind of rejected. He said, like, no, that's probably not possible. And yet, you know, like if he'd only sort of had more discussions with this other community, he would have seen like, no, there are actually windows that open up. And then the next thing is this idea of whether a step is hard or not. Because for hard, what you mean by a hard step is that, like I said, every time there's a generation, every time there's a next generation born, you're rolling the dice on whether this mutation will happen.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

13. “So, you know, what's amazing about this model is it shows how important it is to actually work with people who are in the field, right? So, you know, Brandon Carter was a brilliant physicist, the guy who came up with this. And then lots of physicists and astrophysicists like me have used this, but the people who actually study evolution and the planet were never involved, right? And if you went and talked to an evolutionary biologist or a biogeophysicist, they'd look at you when you explain this to the men, they'd be like, What? Like, what are you guys doing? Turns out none of the details or none of the conceptual structure of this matches with what the people actually study the planet and its evolution.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

14. “Right, and so this was the idea. So, what Carter said was, you know, using anthropic reasoning, he said there must be a few very hard steps for the evolution to get through to make it to intelligence, right? So there's some steps are going to be easy. So every generation, you know, you roll the dice and yeah, it won't take long for you to get that step. But there must be a few of them. And he said you could even calculate how many there were, five, six, in order to get to intelligence. And so this paper here, this plot is all these different people who've written all these papers. And this is the point. Actually, you can see all these papers that were written on the hard steps, each one proposing a different set of what those steps should be. And there's this other idea from biology of the major transitions in evolution, MTEs, that those were the hard steps. But what we actually found was that none of those are actually hard. The whole idea of hard steps, that there are hard steps is actually sus.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

15. “The technosphere is the creation that is a giant perturbation on the biosphere, right? And what you can't do is, you know, the technosphere sits on top of the biosphere. And if the technosphere undermines the biosphere for its own conditions of habitability, then you're in trouble. I mean, the biosphere is not going away. There's nothing we could do. Like the idea that we have to save the earth.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

16. “Yeah. Well, you know what's interesting with the technosphere, we could talk about this more, but like, you know, we're just emerging as a technosphere in terms of as a interplanetary technosphere, right? That's really the next step for us is to, um, David Grinspoon talks about, I love this idea of anti-accretion, like this amazing thing that for the first time, you know, over the entire history of the planet, stuff is coming off the planet, right? It used to be everything just fell down, all the meteorites fell down. But now we're starting to push stuff out. And, you know, like the idea of planetary defense or such, you know, we are actually going to start exerting perturbations on the solar system as a whole. We're going to start engineer if we make it, right? I always like to say that if we can get through climate change, the prize at the end is the solar system, right? So we will be changed literally engineering the solar system. But what you can think of right now with what's happening with the anthropocene, the great acceleration that is.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

17. “Self maintaining life does not create the conditions which will destroy itself, right? It's always trying to keep itself in a place where it can stay alive. So the biosphere from this guyian perspective has been autopoietic for the billions of years. Now we just invented this technosphere in the last couple of hundred years. And what we were arguing in that paper is that it's an immature technosphere, right? Because right now with climate change and all the other things we're doing, the technosphere right now is sort of destroying the conditions under which it needs to maintain itself. So the real job for us, if we're going to last over geologic timescales, if we want a technosphere that's going to last tens of thousands, hundreds of thousands, millions of years, then we've got to become mature, which means to not undermine the conditions, to not subvert the conditions that you need to stay alive.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

18. “Well, that's, I'm glad you asked that question because that paper that David and Sarah and I wrote, what we were arguing was, is that over the history of a planet, when life first forms 3.8 billion years ago, it's kind of thin on the ground, right? You've got the first species. These are all microbes. And they have not yet, they're not going to enough of them to exert any kind of these Gaian feedback. So we call that an immature biosphere. But then as time goes on, as life becomes more robust and it begins to exert these feedbacks, keeping the planet in the place where it needs to be for life. We call that a mature biosphere, right? And the important thing, and we're going to, I'm sure later on we're going to talk about definitions of life and such, there's this great term called autopoiesis that Francisco Varelva, a neurobiologist Francisco Varela, came up with. And he said, you know, one of the defining things about life is this property of auto poesis, which means self-creating and”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

19. “And I think that actually is possible. It's not conscious, but there is a kind of cognitive activity going on. The biosphere in some sense knows what is happening because of these feedbacks. So it's still unclear whether we have these full Gaian feedbacks, but we certainly have semi-Gaian feedbacks. If there's a perturbation on the planetary scale, temperature, you know, insulation, how much sunlight's coming in, the biosphere will start to have feedbacks that will damp that perturbation. Temperature goes up, the biosphere starts doing something, temperature comes down.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

20. “So, okay, what I would say right now is I don't know if I can say that scientifically, I can certainly say that the biosphere does a huge amount of the regulation of the planetary state. And over billions of years has strongly modified the evolution of the planet. So whether or not a true guy in feedback would be exactly what you said, right? The biosphere is somehow, and Sarah Walker and David Grinspoon and I actually did a paper on this about the idea of planetary intelligence or cognition across a planetary scale.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

21. “Kinds of conditions for life. Now, when this theory came out, it was very controversial. People were like, oh my God, you know, what are you smoking weed? And like, there were all these Gaia-in festivals with Gaian dances. And so, you know, it became very popular in the New Age community. But Lovelock, actually, they were able to show that no, this has nothing to do with the planet being conscious or anything. It was about these feedbacks that the biology, the biosphere can exert these feedbacks. And now that's become, whether or not we're still unclear whether there are true Gaiaen feedbacks in the sense that the planet can really exert complete control. But it is absolutely true that the biosphere is a major player in Earth's history.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

22. “Yeah, and we know this for a fact now. Like, this is so there was this thing Gaia theory that, you know, with James Lovelock introduced in the 70s, and then Lynn Margellis, the biologist Lynn Margellis together. So this Gaia theory was the idea that planets pretty much take, or sorry, life takes over a planet. Life hijacks a planet in a way that the sum total of life creates these feedbacks between the planet and the life such that it keeps the planet habitable. It's kind of a homeostasis, right? I can go out like right now outside. It's 100 degrees, right? And I go outside, but my internal temperature is going to the same. And I can go back to, you know, Rochester, New York in the winter, and it's going to be, you know, zero degrees, but my internal temperature is going to be the same. That's homeostasis. The idea of Gaia theory was that life, the biosphere exerts this pressure on the planet or these feedbacks on the planet, that even as other things are changing, the planet will always stay in the right place.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

23. “that broke water apart to work to do its chemical shenanigans. It broke water apart and pushed oxygen into the atmosphere. That's why there's oxygen in the atmosphere. It's only because of life.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

24. “The fate of the earth and the fate of life are inextricably combined. And this is really important for astrobiology too. Life doesn't happen on a planet. It happens to a planet. So this is something that David Grinspoon and Sarah Walker both say and, you know, I agree with this. It's a really nice way of putting it. So play tectonics, the evolution of oxygen, of an oxygen atmosphere, which only happened because of life. These things, you know, these are things that are happening where life and the planet are sort of sloshing back and forth. And so rather than to your point about do you need giant catastrophes, maybe not giant catastrophes, but what happens is as the Earth and life are evolving together, windows are opening up, evolutionary windows. Like, for example, life put oxygen into the atmosphere. When life invented this new form of photosynthesis about two and a half billion years ago,”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

25. “On life are coupled because life and the timescale for evolution of the earth is coupled is about the same timescale as the evolution as the sun. It's billions of years. The earth evolves over billions of years. And life and the earth co-evolve. That's what Brandon Carter didn't see is that actually.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

26. “I was one of these anthropic reasoning kinds of things where Brandon Carter said, Oh, look, the intelligence doesn't show up on Earth until about almost close to when the end of the sun's lifetime. And so he's like, well, there should be no reason why the sun's lifetime and the time for evolution to produce intelligence should be the same. And so therefore, and he goes through all this reasoning, anthropic reasoning, and he ends up with the idea that like, oh, it must be that the odds of getting intelligence are super low. And so that's the hard steps, right? So there was a series of steps in evolution that were very, very hard. And because of that, you can calculate some probability distributions. And everybody loves a good probability distribution. And they went a long way with this. But it turns out that the whole thing is flawed because when you look at it, of course the timescale for the sun's evolution and the timescale for evolution.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

27. “Well, I think what's, I'm not sure if that's true. I don't know if it needs to be an almost extinction event, right? Because it's certainly true that we have gone through almost extinction events, right? We've had five mass extinctions, but you don't necessarily see that there was this giant evolutionary leap happening after those. So, you know, with the comet impact, the KT boundary, certainly, you know, lots of niches opened up. And that's why we're here, right? Because, you know, our ancestors were just little, basically rodents, rats, living under the footsteps of the dinosaurs. And it was that common impact that opened the route for us. But it wasn't, I mean, that still took another, you know, 65 million years. It wasn't like this thing immediately happened. But what we found with this hard steps paper, because the whole idea of the hard steps paper was.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

28. “Somewhere around there is when you get the Cambrian explosion when suddenly everybody plan evolution goes on an orgy essentially. So yeah, it does look like that chaos or that turmoil was actually very helpful to evolution.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

29. “Yeah, that's actually really true because what happens is if you look at the history of life, it's an excellent point you're bringing up. If you look at the history of life on Earth, we get abiogenesis somewhere around at least 3.8 billion years ago. And that's the first microbes. They kind of take over enough that they really do, you get a biosphere. You get a biosphere that is actively changing the planet. But then you go through this period they call the boring billion, where like it's a billion years and it's just microbes. Nothing's happening. It's just microbes. I mean, microbes are doing amazing things. They're inventing fermentation. Thank you very much. We appreciate that. But it's not until sort of you get probably these continent slamming into each other, you really get the beginning of continents forming and driving changes that evolution has to respond to, that on a planetary scale, this turmoil, this chaos, is creating new niches as well as closing other ones. And biology, evolution has to respond to that.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

30. “Shot up by a factor of almost a thousand, right? So the fact that you had plate tectonics supercharged evolution in some sense, like we're not exactly sure how it would happen, but it's clear that the amount of life, the amount of living activity that was happening really got a boost from the fact that suddenly there was this new vigorous form of plate tectonics.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

31. “What I mean by that is that there really weren't many mountain ranges, right? The beginning of, I think the term is orogenesis, mountain building, the true Himalayan style giant mountains didn't happen until this more robust form of plate tectonics where the plates are really being driven around the planet. And that is when you get the crusts hitting each other and they start pushing into these Himalayan style mountains. The weathering of that, the erosion of that puts huge amounts of nutrients, things that microbes want to use into the oceans and then what we call the net primary productivity, the bottom of the food chain, how much sugars they're producing, how much photosynthesis they're doing.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

32. “Even more, there's even more really important things. I just finished a paper where we were looking at something called the hard steps model, which is this model that's been out there for a long time that purports to say intelligent life in the universe will be really rare. And it made all these assumptions about the Earth's history, particularly the history of life and the history of the planet, or have nothing to do with each other. And it turns out, as I was doing the reading for this, that Earth probably early on had a more mild form of plate tectonics and then somewhere about a billion years ago it ramped up. And that ramping up changed everything on the planet because here's a funny thing. The Earth used to be flat. What I mean by that, right? So all the flat earthers out there can get excited for one set clip.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

33. “There's a bunch of different things. One is that, you know, the Earth went through a couple of phases of being a snowball planet. We went into a period of glaciation where the pretty much the entire planet was under ice. The oceans were frozen.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

34. “Ten times the mass of the Earth. And that's exactly where there are no planets in our solar system. The smaller ones of those we call super Earths, the larger ones we call sub-Neptunes. And they're anybody's guess. Like we don't really know what happens to material when you're squeezed to those pressures, which is like millions, tens of millions of times the pressure on the surface of the Earth. So those details really will matter of what's going on in there because that will determine whether or not you have, say, for example, plate tectonics. We think plate tectonics may have been really important for life on Earth, for the evolution of complex life on Earth. So it turns out, and this is sort of the next generation where we're going with the understanding, the evolution of planets and life, it turns out that you actually have to think hard about the planetary context for life. You can't just be like, oh, there's a warm pond, you know, and then some interesting, you know, chemistry happens in the warm pond. You actually have to think about the planet.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

35. “Hugely important. So I'm part of a collaboration at the University of Rochester where we're using the giant laser. It's literally, this is called the Laboratory for Laser Energetics. We got a huge grant from the NSF to use that laser to slam tiny pieces of silica to understand what the conditions are like at the center of the earth or even more importantly the center of super-Earths. This is what's wild. The most common kind of planet in the universe we don't have in our solar system. which is amazing, right? So we've been able to study enough or observe enough planets now to get a census. You know, we pretty, you know, we kind of have an idea of what whose average, who's weird. And our solar system's weird because the average planet has a mass between somewhere between a few times the mass of the earth to maybe, you know,”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

36. “Yeah, I think we can. I think we're learning how to do that now. So, you know, one part is trying to just figure out how planets form themselves and doing the simulations. Like that cascade from dust grains up to planetary embryos, that's hard to simulate because it's both. You got to do both the gas and you got to do the dust and the dust colliding and all that physics. Once you get up to a planet-sized body, then you kind of have to switch over to almost like a different kind of simulation. There often what you're doing is you're doing sort of, you're assuming the planet is this sort of spherical ball and then you're doing like a 1D, a radial calculation. And you're just asking like, all right, how is this thing going to, what is the structure of it going to be? Like, am I going to have a solid iron core? Or am I going to get a solid iron core with that liquid iron core out around it like we have on earth? And then you get, you know, a silicate kind of a rocky mantle and then across all of those details, those are kind of.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

37. “Yeah, so the temperature of the material in the disk depends on how far away you are from the star. So it decreases, right? And so there's a really interesting point. So like, you know, close to the star, temperatures are really high. And the only thing that can condense, that can kind of freeze out is going to be stuff like metals. So that's why you find Mercury as this giant ball of iron, basically. And then as you go further out stuff, you know, the gas gets cooler. And now you can start getting things like water to freeze, right? So there's something we call the snow line, which is somewhere in our solar system out around between Mars and Jupiter. And that's the reason why the giant planets in our solar system, Jupiter, Saturn, Uranus, and Neptune all have huge amounts of ice in them, or water and ice. Actually, Jupiter and Saturn don't have so much, but the moons do. The moons have so much water in them that there's oceans, right? That we've got a number of those moons have.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

38. “Into the disk itself, and you want to do planets, things get a little bit more complicated because the physics gets more complicated. Now you got to start worrying about dust because actually dust, which is just, dust is the wrong word. It's smoke, really. These are the tiniest bits of solids. They will coagulate in the disk to form pebbles, right? And then the pebbles will collide to form rocks. And then the rocks will form boulders, et cetera, et cetera. That process is super complicated. But we've been able to simulate enough of it to begin to get a handle on how planets form, how you accrete enough material to get the first proto-planets or planetary embryos, as we call them. And then the next step is those things start slamming into each other to form planetary-sized bodies. And then the planetary bodies slam into each other. Earth, the moon came about because there was a Mars-sized body that slammed into the Earth and basically blew off all the material.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

39. “That actually we're able to do now. There is you can run simulations of the formation of planetary system. So if you run the simulation really where you want to start is a cloud of gas, these giant interstellar clouds of gas that may have a million times the mass of the sun in them. And so you run a simulation of that. It's turbulent. The gas is roiling and tumbling. And every now and then you get a place where the gas is dense enough that gravity gets hold of it and it can pull it downward. So you'll start to form a protostar. And a protostar is basically the young star of this ball of gas where nuclear reactions are getting started. But it's also a disk. So as material falls inward because everything's rotating as it falls inward, it'll spin up and then it'll form a disc. Material will collect in what's called an accretion disc or a protoplanetary disk. And you can simulate all of that once you get...”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

40. “Opinions about how common planets we're going to be and how unique Earth was. And that question got answered, right? Which is pretty remarkable that in a lifetime you can have a 2,500-year-old question. The answer is they're everywhere. There are planets everywhere. And it was possible that planets were really rare. We didn't really understand how planets formed. And so if you go back to, say, the turn of the 20th century, there was a theory that said planets formed when two stars passed by each other closely and then material was gravitationally squeezed out, in which case those kinds of collisions are so rare that you would expect one in a trillion stars to have planets. Instead, every star in the night sky has planets.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source

41. “That's the question, right? The amazing thing is that after two and a half millennia of people yelling at each other or setting each other on fire occasionally over the answer, we now actually have the capacity to answer that question. So in the next 10, 20, 30 years, we're going to have data relevant to the answer to that question. We're going to have hard data finally that will, one way or the other, you know, even if we don't find anything immediately, we will have gone through a number of planets. We'll be able to start putting limits on how common life is. The one answer I can tell you, which is an important part of the problem, is how many planets are there, right? And just like people have been arguing about the existence of life elsewhere for 2500 years, people have been arguing about planets for the exact same amount of time, right? You can see Aristotle yelling at Democratus about this. You can see the head very wildly different.”

    2024-12-22 · Lex Fridman Podcast · #455 – Adam Frank: Alien Civilizations and the Search for Extraterrestrial Life · IDENTIFIED FROM THE TRANSCRIPT · source