Lex Fridman PodcastAdam Frank: Alien Civilizations and the Search for Extraterrestrial Life | Lex Fridman Podcast #455
EVERY SPOKEN WORD
150 min read · 30,032 words- 0:00 – 1:58
Introduction
- AFAdam Frank
... if we don't ask how long they last, but instead ask what's the probability that there have been any civilizations at all, no matter how long they lasted. And I'm not asking whether they exist now or not, I'm just asking in general, um, about probabilities to make a technological civilization anywhere and at any time in the history of the universe. And that we were able to constrain. And so what we found was basically, uh, that the, there have been 10 billion trillion habitable zone planets in the universe. And what that means is, that are, those are 10 billion trillion experiments that have been run. Um, and the only way that we're the only time that this is, you know, this whole process from bi-, you know, uh, abiogenesis to a civilization has occurred, is if every one of those experiments failed, right? So therefore, you could put a, a probability... You could just... We called it the pessimism line, right? We don't really know what nature sets for the probability of making intelligent civilizations, right? But we could set a limit to using this. We could say, look, as... If the probability per habitable zone planet is less than 10 to the minus 22, one in 10 billion trillion, then yeah, we're alone. If it's anywhere larger than that, then they're, we're not the first. It's happened somewhere else. And to me that was an anno-, that was mind-blowing. Doesn't tell me there's anybody nearby, the galaxy could be sterile. It just told me that, like, you know, uh, unless nature's really against, has some bias against civilizations, we're not the first time this has happened. This has happened elsewhere over the course of cosmic history.
- LFLex Fridman
The following is a conversation with Adam Frank, an astrophysicist interested in the evolution of star systems and the search for alien civilizations in our universe. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description. And now, dear friends, here's Adam Frank.
- 1:58 – 7:08
Planet formation
- LFLex Fridman
You wrote a book about aliens. So the big question, how many alien civilizations are out there?
- AFAdam Frank
Yeah, that's the question, right? The amazing thing is that after two and a half millennia of, you know, 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 gonna have data relevant to the answer to that question. We're gonna 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. Uh, the one answer I can tell you, uh, which is, was an important part of the problem is how many planets are there, right? And just like people have been arguing about the, uh, existence of life elsewhere for 2,500 years, people have been arguing about planets for the exact same amount of time, right? You can see Aristotle yelling at Democritus about this. You know, you can see they had very wildly different opinions about how common planets were gonna be and how unique Earth was. And that question got answered, right? Which is pretty remarkable that, uh, 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, uh, 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, uh, 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, uh, 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.
- LFLex Fridman
So one of the things you've done is, uh, simulated the formation of stars. How difficult do you think it is to simulate the formation of planets, like simulate a solar system? The, through the entire evolution of the solar system. This is kind of a, a numerical simulation sneaking up to the question of how many planets are there.
- AFAdam Frank
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 y- really where you wanna start is a cloud of gas, these giant interstellar clouds of gas that may have, you know, 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 m-, uh, the gas is dense enough that gravity gets ahold 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 the, you know, this ball of gas where, uh, nuclear reactions are getting started, but it's also a disk. So you, as material falls inward, because it's, everything's rotating, as it falls inward it'll spin up and then it'll form a disk. The material will collect in what's called an accretion disk or a protoplanetary disk. And you can simulate all of that. Once you get into the disk itself and you wanna do planets, things get a little bit more complicated 'cause the physics gets more complicated. Now you gotta start worrying about dust, 'cause 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 protoplanets or planetary embryos as we call 'em. And then they'll, some, the next step is those things start slamming into each other to form, you know, 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 that ev- then eventually formed the moon.
- LFLex Fridman
And all of them have, uh, different chemical compositions, different temperatures?
- AFAdam Frank
Yeah, so the- the- the temperature of the material in the disk depends on how far away you are from the star.
- LFLex Fridman
Got it.
- AFAdam Frank
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, um, Uranus, and Neptune all have huge amounts of ice in them, or water and ice. Um, actually Jupiter and Saturn don't have so much, but the moons do. The moons have so much water in them that there's l- there's oceans, right? That we've got a number of those moons have got more water on them than there's water on Earth.
- LFLex Fridman
Do you think it's possible to do that kind of simulation to have a stronger and stronger estimate of, uh, how likely an Earth-like planet
- 7:08 – 14:30
Plate tectonics
- LFLex Fridman
is? Can we get the physics simulation done well enough to where we can start estimating? Like, what are the possible Earth-like things that can be generated?
- AFAdam Frank
Yeah, I think we can. I think we're learning how to do that now. Um, so, you know, one part is, like, trying to just figure out how to- how planets form themselves and doing the simulations. Like that- that cascade from, uh, dust grains up to planetary embryos, that's hard to simulate because it's both. You gotta do both the gas and you gotta do the dust, and the dust colliding, and all that physics. Um, once you get up to a planet sized body, then, you know, you kinda have to switch over to almost, like, a different kind of simulation. There, often what you're doing is you're doing, you know, sort of, you're assuming the planet is this sort of spherical ball, and then you're doing what, you know, like a 1-D, a radial calculation, and you're just asking, like, "All right, how is this thing going to... What is the structure of it gonna be? Like, am I gonna have a solid iron core or am I gonna get a solid iron core with a liquid iron core out around it like we have on- on Earth?" And then you get, you know, a silicate, kind of a rocky mantle, and then a crust. All those details, those are kind of beyond being able to do full 3D simulations from ab initio, from scratch. We're not there yet.
- LFLex Fridman
Uh, how important are those details, like the crust and the atmosphere, do you think?
- AFAdam Frank
Hugely important. So I- I'm part of a collaboration at the University of Rochester where we're using, uh, the giant laser. It's literally-
- LFLex Fridman
Yeah.
- AFAdam Frank
... this is called the Laboratory for Laser Energetics. We got a huge grant from the NSF to use that laser to, like, slam tiny pieces of silica to understand what c- conditions are like at, you know, the center of the Earth, or even more importantly, the center of super Earths. Like, the most com- 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 the, uh, we've been able to study enough, or observe enough planets now to get a census. You know, we pretty, you know, we kinda have an idea-
- LFLex Fridman
Yeah.
- AFAdam Frank
... of what, who's average, who's weird, um, 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, 10 times the mass of the Earth, and that's exactly where there are no planets in our solar system. So, um, 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- 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- 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 as a whole and what it's gone through in order to really understand whether a planet is a good place for life or not.
- LFLex Fridman
Why do you think plate tectonics might be inter- uh, useful for the formation of complex life?
- AFAdam Frank
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. Like we, you know, we went into a period of glaciation-
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
... where the- pretty much the entire planet was under ice. The- the oceans were frozen. Um, you know, early on in Earth's history, there was no, there was barely any land. We were actually a water world, you know, with just a couple of, um, Australia sized cratons they call them, proto-continents. So those, uh, we went through these snowball Earth phases, and if it wasn't for the fact that we had kind of an active plate tectonics, which had a lot of volcanism on it, um, we could've been locked in that forever. Like, once you get into a snowball state, a planet can be trapped there forever, which is, you know, maybe you already had life form, but then because it's so cold, you may never get anything more than just microbes, right? So what plate tectonics does is, it- because it fosters more, um, uh, volcanism is that you're gonna get carbon dioxide pumped into the atmosphere which warms the planet up and gets you out of the, uh, the, uh, snowball Earth phase. But 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 that the history of life and the history of the planet are- have nothing to do with each other, and it turns out in- as I was doing the reading for this, that, um, Earth probably early on had a- 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 'cause here's a funny thing. The Earth used to be flat. (laughs) And what I mean by that, right, so all the flat Earthers out there can get excited for one sec.
- LFLex Fridman
Clip it.
- AFAdam Frank
(laughs) What I meant by-
- LFLex Fridman
Still is.
- AFAdam Frank
(laughs) 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, you know, into these Himalayan style mountains. The weathering of that, the erosion of that puts huge amounts of nutrients, you know, things that microbes wanna use, uh, into the oceans, and then the, what we call the net primary productivity, the, you know, the photo... The, the, the bottom of the food chain, how much sugars they're producing, how much photosynthesis they're doing, shot up by a factor of a- almost 1,000, right? So the, the fact that you had plate tectonics supercharged evolution in some sense, you know? Like, we're not exactly sure how, how, how it happened, 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 plate te- this new vigorous form of plate tectonics.
- LFLex Fridman
So it's nice to have turmoil in terms of temperature, in terms of, uh, surface geometries, in terms of the chemistry of the planet, turmoil.
- AFAdam Frank
Yeah, that's actually really true because what happens is if you look at the history of life, that's a really, you know, it's an excellent point you're bringing up. If you look at the history of life on Earth, we get, uh, you know, abiogenesis somewhere around at, at least 3.8 billion years ago, and that's the first microbes. They kinda 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, they're, they're doing, microbes are doing amazing things, they're inventing, uh, um, fermentation. Thank you very much for (laughs) we appreciate that. Um, but it's not until sort of you get probably this, these continents 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, and somewhere around there is when you get the Cambrian explosion, is when suddenly every body plan, um, you know, e- evolution goes on an orgy essentially. Uh, so yeah, it does look like the, that chaos or that turmoil was actually very helpful
- 14:30 – 18:41
Extinction events
- AFAdam Frank
to evolution.
- LFLex Fridman
I wonder if there's some, uh, extremely elevated levels of chaos, almost like catastrophes behind every leap of evolution. Like, you're not gonna have leaps, um... Like in hu- in, in human societies, we have, like, an Einstein that comes up with a good idea, but it feels like in an evolutionary timescale, you need some real big drama going on for, for the evolutionary system to have to come up to a solution to that drama, like an extra complex solution to that drama.
- AFAdam Frank
Well, I think what's... I'm not sure if that's true. I don't know if it needs to be, like, an o- an almost-extinction event, right?
- LFLex Fridman
Right.
- AFAdam Frank
'Cause it's certainly true that we have gone through almost-extinction events, right? We've had, you know, uh, five ma- mass extinctions. But you don't necessarily see that, like, there was this giant evolutionary leap happening-
- LFLex Fridman
Right.
- AFAdam Frank
... after those. So, you know, with the, uh, comet impact, um, the K-T boundary, certainly, you know, lots of niches opened up and that's why we're here, right? 'Cause, you know, our ancestors were just little, basically rodents, rats living under the footsteps of the dinosaurs, and it was that comet impact that opened the, um, 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, 'cause the whole idea of the hard steps paper was, it was one of these, uh, anthropic reasoning kinds of things, where Brandon Carter said, "Oh, look, the intelligence doesn't show up on Earth-"
- LFLex Fridman
(laughs)
- AFAdam Frank
"... until about, um, you know, almost close to when the end of the sun's lifetime." Uh, 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." Uh, "And so therefore..." And he goes through all this reasoning, anthropic reasoning and, and, 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, you know, very, very hard. And because of that, you can calculate some probability distributions.
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
Um, 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 on one... You know, when you look at it, of course the timescale for the sun's evolution and the timescale for evolution on life are coupled because life and the... The, 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 the fate of the Earth and the fate of life are inextricably combined. Uh, and this is really important for astrobiology too. Um, life doesn't happen on, uh, on a planet, it happens to a planet. So this is something that David Grinspoon and Sara Walker both say and, you know, uh, uh, I agree with this. It's a really nice way of putting it. Um, so, uh, you know, plate tectonics, um, the evolution of oxygen, of an oxygen atmosphere, which only happened because of life, um, these things, you know, these are, are things that are happening where life and the planet are sort of sloshing back and forth.
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
And so rather than, to your, 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, when life invented this new form of photosynthesis about two and a half billion years ago...... that broke water apart to, you know, work, to do its, its shenan- chemical shenanigans. Um, it broke water apart and pushed oxygen into the atmosphere. That's why there's oxygen in the atmosphere, it's only 'cause of life. Um, that opened up huge possibilities, new spaces for evolution to happen. But it also changed the chemistry of the planet forever. So the evolu- the introduction of, of a, of oxygen photosynthesis changed the planet forever, and it opened up a bunch of windows for evolution that wouldn't have happened otherwise. Like for example, you and I, we need that amount of oxygen. Big-brained creatures need an oxygen-rich atmosphere 'cause oxygen is so potent, uh, um, for metabolism. So you couldn't get intelligent creatures 100 million years after the planet formed.
- 18:41 – 21:39
Biosphere
- AFAdam Frank
- LFLex Fridman
So really on a scale of a planet when there's, uh, billions, trillions of organisms on a planet, they can actually have planetary scale impact.
- AFAdam Frank
Yeah.
- LFLex Fridman
So, so the chemical shenanigans of an individual organism when scaled out to trillions can actually change a planet?
- AFAdam Frank
Yeah. A- and we know this for a fact now. Like this is... So there was this thing, Gaia Theory that, you know, with James Lovelock, uh, introduced in the '70s, um, and then Lynn Margulis, the biologist Lynn Margulis together. So this, Gaia Theory was the idea that planets pretty much take o- or sorry, life takes over a planet.
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
Life hijacks a planet in a way that, um, 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 is 100 degrees, right? And I go outside, but my internal temperature's gonna be the same. And I can go back to, you know, Rochester, New York in the winter and it's gonna be, you know, zero degrees, but my internal temperature's gonna be the same. That's homeostasis. The idea of Gaia Theory was that life, uh, 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 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?" You know, and like, and there were all these Gaian festivals with Gaian, uh, 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, like, the planet being conscious or anything. It was about these feedbacks that, that bi- the biology, the biosphere can exert these feedbacks. And now that's become whether or not it's still, we're still unclear whether there are true Gaian feedbacks in the sense that the planet can really exert complete control, but it is absolutely true that, um, the biosphere is a major player in Earth's history.
- LFLex Fridman
So the biosphere fights for homeostasis on Earth?
- AFAdam Frank
The bio- 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 Ga- a true Gaian feedback would be exactly what you said, right? The Ga- the biosphere is this somehow... And Sara Walker and David Grinspoon and I actually did a paper on this, about the idea of planetary intelligence or cognition across a planetary scale. 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. Um, so but w- so it's still unclear whether we have these full Gaian feedbacks, but it, we certainly have semi-Gaian feedbacks. If there's a perturbation on the planetary scale, temperature, you know, insolation, 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.
- 21:39 – 25:53
Technosphere
- AFAdam Frank
- LFLex Fridman
Now I wonder if the technosphere also has a Gaian feedback or elements of a Gaian feedback such that the technosphere will also fight, to some degree, for homeostasis. Open question, I guess.
- AFAdam Frank
Well that's, I'm glad you asked that question because that, that, that paper that David and, uh, uh, Sara and I wrote, what we were arguing was, is that over the history of a planet, right, when life first forms, you know, 3.8 billion years ago, it's kinda thin on the ground, right? You've got the first species b- c- you know, um, these are all microbes. And they have not yet, uh, been a- there are not gonna be enough of them to exert any kind of these Gaian feedbacks. So we call that an immature biosphere.
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
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 gonna, I'm sure later on we're gonna talk about definitions of life and such, there's this great term called autopoiesis, uh, that Francisco, uh, Varela, neurobiologist Francisco Varela came up with. And he said, you know, one of the defining things about life is this property of autopoiesis, which means self-creating and 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 Gaian perspective, has been autopoeitic for the, you know, billions of years. Now we just invented this technosphere in the last, you know, couple of hundred years, and what we were arguing in that paper is that it's an immature technosphere, right? 'Cause right now with climate change and all the other things we're doing, we don't, we're dest- 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 gonna last over, you know, geologic time scales, if we want a technosphere that's gonna last tens of thousands, hundreds of thousands, millions of years, then we've gotta become mature, which means to not, uh, undermine the conditions, to not subvert the conditions that you need to stay alive. So as of right now, I'd say we're not autopoeitic.
- LFLex Fridman
Well, I wonder if we look across thousands, tens of thousands, hundreds of thousands of years, that perturbations, the technosphere should create perturbations.Eh, as a way for developing greater and greater defenses against perturbations, which sounds like a ridiculous statement. But basically, uh, go out and play in the yard and hurt yourself to-
- AFAdam Frank
(laughs)
- LFLex Fridman
... to strengthen the im- or like drink water from the, from the pond.
- AFAdam Frank
From the pond. (laughs) Yeah. Right.
- LFLex Fridman
To strengthen-
- AFAdam Frank
Get sick a few times.
- LFLex Fridman
... to strengthen the immune system.
- AFAdam Frank
Yeah. Well, you know, it's interesting with the technosphere, we could talk about this more, but like, you know, the te- 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 it. 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, um, and, you know, like the idea of planetary defense or such, you know, we are actually gonna start exerting perturbations on the solar system as a whole. We're go- we're gonna start engineer- if we make it, right? I- I always like to say that if we can get through climate change, the prize at the end is the solar system, right?
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
Uh, so we will, um, will be change- literally engineering the solar system. But what you can think of right now with what's happening with the Anthropocene, the great acceleration that, that, uh, the- is the technosphere, you know, is the creation of the... 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 the techno- if the technosphere undermines the biosphere for its own conditions of habitability, then you're in trouble, right? I mean, the biosphere's not going away. There's nothing we could do. Like, the idea that we have to save the earth is a little ridiculous. Like, the earth is not a furry little bunny that we need to protect.
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
But it's the conditions for us, right? We, humanity emerged out of this, out of the Holocene, the last 10,000 years interglacial period. We can't tolerate very different kinds of earths. Um, so that's what I mean about a perturbation.
- 25:53 – 32:06
Emergence of intelligence
- AFAdam Frank
- LFLex Fridman
Before we forget, I gotta ask you about this paper.
- AFAdam Frank
Right.
- LFLex Fridman
Pretty interesting. Uh, there's an interesting table here about hard steps.
- AFAdam Frank
Yeah.
- LFLex Fridman
Abiogenesis, glucose fermentation to pyruvic acid, all kinds of steps, all the way to homo sapiens, animal intelligence, land ecosystems, endoskeletons, eye precursor, so formation of the eye.
- AFAdam Frank
Yeah.
- LFLex Fridman
Complex multicellularity.
- AFAdam Frank
That's definitely one of the big ones.
- LFLex Fridman
Yeah. So in- interesting. I mean, what can you say about this chart? There are all kinds of papers talking about what the difficulty of these steps?
- AFAdam Frank
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 evolution to get through to make it to intelligence," right? So there's some steps that are gonna 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 what- 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 suspect. So, you know, this- what's amazing about this model is it shows how important it is to actually work with people who are in the field, right?
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
So, you know, Brandon Carter was a, you know, brilliant physicist, the guy who came up with this. Um, and then lots of physicists and astrophysicists like me have used this. But the people who actually study evolution and the planet-
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
... 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 them and they'd be like, "What?" (laughs) Like, "What are you guys doing?" Turns out none of the, uh, details or n- none of the conceptual structure of this matches with what the people actually who study the planet and its evolution.
- LFLex Fridman
Is it mostly about the, the fact that there's not really discreet big steps? It's, it's a gradual continual kind of process?
- AFAdam Frank
Well, there's two things. The first most important one was that the planet and the biosphere have evolved together.
- LFLex Fridman
Yeah.
- AFAdam Frank
That's something that every, you know, 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, you know, there are actually windows that open up. And then the next thing is this idea of whether a step is hard or not. 'Cause for hard what, what you mean by s- a hard step is like I said, every time there's a generation, every time there's the next generation born, you're rolling the dice on whether this mutation will happen. 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. Uh, we sh- 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 a har- making wings is not a hard step. There are certain other things that people say, "No, that's a hard step." Uh, oxygen, you know, the oxygen, uh, photosynthe- synthesis. 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, uh, you know, went, made this i- 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 basically the, the, the, 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, how much once you look at the details of life's history on Earth, how it sh- really shifts you away from this hard steps model. And it shows you that those details that we were talking about like with do you have to know about the planet? Do you have to know about plate tectonics? Yeah, you're going to have to.
- LFLex Fridman
I mean, to be fair to Carter on the first point, it makes it much more complicated, uh, if life and the planet are co-evolving, because it's ni- it would be nice to consider the planet as a static thing that sets the initial conditions-
- AFAdam Frank
Yeah.
- LFLex Fridman
... and then we can sort of, from an outside perspective, analyze planets based on the initial conditions they create, and then there- there's a binary yes or no, will it create life? But if they co-evolve, it's just like a, it's a really complex dynamical system-
- AFAdam Frank
Yeah.
- LFLex Fridman
... where everything is, uh, becomes much more difficult from the perspective of SETI, of looking out there and trying to figure out which ones-
- AFAdam Frank
Yeah.
- LFLex Fridman
... are actually producing life.
- AFAdam Frank
But I think we're at the point now, so now there may be other kinds of principles that actually... 'Cause you know, co-evolution actually has its own, not deterministic, you're done with determinism, right?
- LFLex Fridman
Yeah.
- AFAdam Frank
But, but you, but complex systems have patterns. Complex systems-
- LFLex Fridman
Yeah.
- 32:06 – 36:20
Drake equation
- LFLex Fridman
let's return back to the question of how many alien civilizations are out there and, uh, talk about the Drake equation.
- AFAdam Frank
Yeah.
- LFLex Fridman
Can you, uh, explain the Drake equation?
- AFAdam Frank
You know, people have various, uh, feelings about the Drake equation. Uh, it, you know, it can be abused, but basically it was... The- the story actually is really interesting. So Frank Drake-
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
... in, uh, 1960 does the first ever astrobiological experiment. He d- gets a radio telescope, points it at a couple of stars, and listens for signals. That was the first time anybody had done any experiment about any kind of life in the history of humanity. Um, 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 that says, "Hey, we want you to ha- do a, um, 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 gonna be there as well. Uh, and like the night before, Drake has to come up with a, uh, uh, an agenda. How do you come up for an ag- with a- an agenda for a meeting on a topic that no one's ever talked about before? Right?
- LFLex Fridman
(laughs)
- AFAdam Frank
And so he actually writ- he breaks, what he does, what's so brilliant about the Drake equation is he breaks the problem of how many civilizations are there out there into a bunch of sub-problems, right? And he breaks it into seven sub-problems. Each one of them is a factor in an equation that when you multiply them all together, you get the number of civilizations out there that we could communicate with. So the first term is the rate at which stars form. The second term is the fraction of those stars that have planets, F sub P. The next term is the number of planets in the habitable zone, the place where we think life could form. Uh, the next term after that is the fraction of those planets where actually an abiogenesis event, lifeforms, occurs. 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 (laughs) care about, is the lifetime. How long you have a civilization, now how long does it last?
- LFLex Fridman
When you say we, we humans?
- AFAdam Frank
We humans, right? 'Cause we're standing, we're staring at the gu- or, you know, multiple guns pointing at us.
- LFLex Fridman
Yeah.
- AFAdam Frank
You know, nuclear war, climate change, AI. Um, so you know, how long on- 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 it 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. Um, so you know, the star people could figure out how many stars were forming per year. The- the people who were interested in planets could go out and find techniques to discover planets, uh, et cetera, et cetera.
- LFLex Fridman
I mean, these are their own fields. Essentially by creating this equation, he's launching new fields.
- AFAdam Frank
Yeah. That's exac- he gave a- astrobiology, which wasn't even a term then, a roadmap.
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
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, uh, uh, uh, you know, sort of marching orders-
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
... for all these different groups. Like for example, it's because of the Drake equation in some sense that um, people who were involved in SETI pushed NASA to develop the technologies for planet hunting. There was this amazing meeting in 1978 and 19... Two 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- what's the roadmap for us to develop technologies to find, find planets?" So, um, yeah, so you know, the Drake equation is absolutely, uh, uh, uh, foundational for astrobiology, but we should remember that it's not a law of nature, right? It's not something that's g- it's not E 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. Um, you know, I'm not sure where my paper fits in on those, so 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 a- that astrobiology faces, this really-... broke it up in a useful way.
- 36:20 – 39:04
Exoplanets
- AFAdam Frank
- LFLex Fridman
We could talk about each one of these, but let- let's just look at exo-planets.
- AFAdam Frank
Yeah.
- LFLex Fridman
So that's a really interesting one. I think, when you look back, you know, hundreds of years from now, what is it, in the '90s when they first detected the first-
- AFAdam Frank
90, yeah, '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.
- LFLex Fridman
I, I think that's, like, one of the greatest discoveries in the, in the history of science.
- AFAdam Frank
I agree. I agree.
- LFLex Fridman
Right now, I guess nobody's celebrating it too much because you don't know what it really means. But I think once we almost certainly will find life out there, it will o- obviously allow us to generalize across the entire galaxy, the entire universe. So if you can find life on a planet, even in the solar system, you can now start generalizing across the entire universe.
- AFAdam Frank
You can. All you need is one, like right now it's an any, you know... Our u- 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 don't have to find all the other examples. You just know that it's happened more than once, and now you are, uh, you know, in... From a Bayesian perspective, you can start thinking like, "Yeah, yeah. This is, life is not something that's hard to make."
- LFLex Fridman
Well, let me get your sense of, uh, estimates for the Drake equation. You also written a paper expanding on the Drake equation, but what- what do you th- what do you think is the answer?
- AFAdam Frank
So the paper, there was this paper we wrote, uh, Woody Sullivan and I, in 2016, where we said, "Look, we have all this exoplanet data now," right? The s- so the thing that exoplanet science and the exoplanet census I was talking about before have nailed is f sub p, the fraction of stars that have planets, it's one. Every fricking star (laughs) that you see in the sky hosts a family of worlds. I mean, it's mind-boggling 'cause every one of those, those are all places, right? They're either, you know, gas giants, probably with moons, so there, the moons are places you can stand and look out. Or they're like terrestrial worlds where even if there's not life, there's still snow falling and there's oceans washing up on, you know, on shorelines. It's incredible to think how many places and stories there are out there. So, right, the first term was f sub p, which is how many stars have planets. The next term is how many planets are in the habitable zone, right? On average. And it turns out to be one over five, right? So, you know, you know, around .2. So that means you just count five of 'em. Go out at night and go, "One, two, three, four, five." One of them has an, an Earth-like planet (laughs) , you know, in the habitable zone. Like, whoa!
- LFLex Fridman
So what, what defines a habitable zone?
- AFAdam Frank
Habitable zone is an idea,
- 39:04 – 42:06
Habitable zones
- AFAdam Frank
um, that was developed in the, um, uh, 1958 by the Chinese-American astronomer Shushang. And it was, it was a brilliant idea. It said, "Look, this is, there i- You know, I can do this simple calculation. If I, I take a planet and just stick it at some distance from a star of, what's the temperature of the planet? What's the temperature of the surface?" So now you're, all you're gonna ask, you give it a standard kind of, you know, Earth-like atmosphere and ask, "Could there be liquid water on the surface," right? We believe that liquid water is really important for life. There could be other things that's happening, fine, but, you know, if you were to start off trying to make life, you'd probably choose water as your solvent for it. So basically, the habitable zone is the band of orbits around a star where you can have liquid water on the surface. You could take a, you know, glass of water, pour it on the surface, and it would just pool up. It wouldn't freeze immediately, which would happen if your planet is too far out, and it wouldn't just boil away if your planet's too close in. So that's the formal definition of the habitable zone. So it's a nice strict definition. There's probably way more going on than that, but this is a place to start.
- LFLex Fridman
Right. Well, we should say it's a place to start. I, I do think it's too strict of a constraint.
- AFAdam Frank
I would agree.
- LFLex Fridman
We're talking about (laughs) temperature where water can be on the surface. There, there's so many other ways to get, uh, the aforementioned turmoil-
- AFAdam Frank
Yeah.
- LFLex Fridman
... where the temperature varies, whether it's volcanic, uh, so interaction of volcanoes and ice and all of this on the moons of planets that are much farther away-
- AFAdam Frank
Yeah.
- LFLex Fridman
... all this kind of stuff.
- AFAdam Frank
Yeah. Well, for example, we know in our own solar system, we have, say, Europa, the moon of Jupiter, which has got a 100-mile deep ocean under 10 miles of ice, right? That's not in the habitable zone. That is outside (laughs) the habitable zone. And that may be the best place. It's got more water than Earth does, all of its oceans. Or, you know, it's twice as much water on Europa than there is on Earth. So, you know, that may be a really great place for life to form, and it's outside the habitable zone. So, you know, the habitable zone is a good place to start, and it helps us... And there's reason, there's reasons why you do wanna focus on the habitable zone because, like Europa, I couldn't, I won't be able to see from across telescopic distances, across light years. I, I wouldn't be able to see life on Europa because it's under 10 miles of ice, right? So with... The important thing about, um, s- planets in the habitable zone is that we're thinking they have atmospheres. Um, atmospheres are the things we can characterize for, across 10, 50 light years, and we can see biosignatures, as we're gonna talk about. So there is a reason why the habitable zone becomes important for the detection of extra-solar life.
- LFLex Fridman
But for me, when I look up at the stars, it's very likely that there's a habitable planet or moon in each of the stars. Habitable defined broadly.
- AFAdam Frank
Yeah, I think that's, that's not unreasonable to say. I mean, es- especially since the, the formal definition, you get one in five, right? One in five is a lot. There's a lot of stars in the sky. So yeah, saying that in general, when I look at a star, there's a pretty good chance that there's something habitable orbiting it is not a unreasonable scientific claim.
- 42:06 – 51:04
Fermi Paradox
- AFAdam Frank
- LFLex Fridman
To me, it seems like there should be alien civilizations everywhere. Why the Fermi paradox? Why haven't we seen them?
- AFAdam Frank
Okay.... the Fermi paradox. Let's talk about the F- I love talking about the Fermi paradox because there is no Fermi paradox. Dun-dun-dun-dun. Yeah, so the Fermi paradox, let's talk a little about the Fermi paradox and the history of it. Um, so, uh, uh, Enrico Fermi, it's 1950, he's walking with his friends at Los Alamos Nuclear Weapons Lab to the cantina, and there had been this, um, cartoon in The New Yorker. They all read The New Yorker. Uh, and the cartoon was trying to explain why there had been this rash of, uh, uh, uh, garbage cans being disappearing in New York. And this cartoon said, "Oh, it's UFOs." 'Cause this is already, you know, it's 1950, the first big UFO craze happened in '47. So they'd all... They were laughing about this as they're walking, and they started, being physicists, started talking about interstellar travel, interstellar propulsion, blah blah blah. You know, conversation goes on for a while. Conversation turns to something else, you know, they've gone to other things. About 40 minutes later, over lunch, Fermi blurts out, "Well, where is everybody?" Right? Typical Fermi sort of thing. He'd done the calculation in his head and he suddenly realized that, look, if one... If there... You know, if intelligence is common, that even traveling at sub-light speeds, a, uh, a civilization could cross, you know, kinda hop from one star system to the other and spread out across the entire galaxy in a few hundred thousand years. And he realized this and so he was like, "Why aren't they here now?" Um, and that was the beginning of the Fermi paradox. It actually got picked up as a formal thing in 1975, uh, in a paper by Hart, where he actually kinda went through this calculation and showed and said, "Well, there's nobody here now, therefore there's nobody anywhere." That, you know... Okay, so that is what we will call the direct Fermi paradox. Why aren't they here now? But something happened where people, after SETI began, where people started to... There, there was this idea of the great silence. People got this idea in their head that, like, "Oh, we've been looking for decades now for signals of extraterrestrial intelligence and we haven't found any, therefore there's nothing out there." But that, so we'll call that the indirect Fermi paradox, and there absolutely is no indirect Fermi paradox for the most mundane of reasons, which is money. There's never been any money to look. There really... SETI was always done by researchers who were kinda like scabbing some time, you know, some extra time from their other projects to, you know, look a little bit, uh, you know, at the sky with a telescope. Telescopes are expensive. So, um, Jason Wright, my, one of my collaborators, he and his students did a study where they looked at the entire search space for SETI. You know, and imagine that's an ocean, all the different stars you have to look at, the radio frequencies you have to look at, how, when you look, how often you look, and they, they looked... Then they summed up all the SETI searches that had ever been done. They went through the literature, and what they found was if the, if the, if that search space, if the sky is an ocean and you're looking for fish, how much of the ocean have we looked at? And it turns out to be a hot tub. That's how much of the ocean that we've looked up. We've dragged an, a hot tub's worth of ocean water up and there was no fish in it, and so now are we gonna say, "Oh, well, there's no fish in the ocean," right? So there is absolutely, positively no indirect Fermi paradox. We just haven't looked. Um, but we're starting to look, so that's what's... You know, finally we're starting to look. That's what's exciting. The direct Fermi paradox, there are so many ways out of that, right? There's a book called 77 Solutions (laughing) to the Fermi Paradox, that it just, you know, you can pick your favorite one. It just doesn't carry a lot of weight because there's so many ways around it. We did an actual simulation, my group, uh, Jonathan Carroll, um, m- one of my collaborators, we actually simulated the galaxy and we simulated probes moving at sub-light speed from one, uh, uh, star to the other, gathering resources, heading to the next one. Um, and so we could actually track the expansion wave across the galaxy, have one IA biogenesis event, and then watch the whole galaxy get colonized or settled. And it is absolutely true that that wave crosses... You know, Hart was right, Fermi was right, that wave crosses very quickly. But civilizations don't last forever, right? So one question is, when did they visit? When did they come to Earth, right? So if you give civilizations a finite lifetime, you know, let them last 10,000, 100,000 years, what you find is you now have a steady state. Civilizations are dying, they're, you know, they're, they're coming back. They're traveling between the stars. What you find then is you can have big holes opened up. You can have regions of space where there is nobody for, you know, millions of years. And so if that, if we're living in one of those bubbles right now, then maybe we were visited, but we were visited 100 million years ago. And there was a paper that Gavin Schmidt and I did that showed that if there was a civilization, whether it was, like, dinosaurs or aliens that was here 100 million years ago, there's no way to tell. There's just, there's no record left over. The fossil record is too sparse. The only way maybe you could tell is by looking at the isotopic, uh, uh, strata, uh, to see if there was anything reminiscent of an industrial civilization. But the idea that, you know, you'd be able to find, you know, iPhones or, or toppled buildings after 100 million years is... There's no way.
- LFLex Fridman
So if there was an alien camp here-
- AFAdam Frank
Yeah.
- LFLex Fridman
... an alien village, a small civilization-
- AFAdam Frank
Right.
- LFLex Fridman
... maybe even a large civilization-
- AFAdam Frank
Even a large civilization, even if it was a large-
- LFLex Fridman
100 million years ago-
- AFAdam Frank
And it lasted 10,000 years, fossil record's not gonna have it. Yeah, yeah. The fossil record is too sparse, right? Most things don't fossilize.
- LFLex Fridman
Yeah.
- AFAdam Frank
Um, and 10,000 years is a, you know, blink in the eye of geological time. So we call, or Gavin called this the Silorian hypothesis after the Doctor Who episode with the lizard creatures, the Silorians. Um, and so that, but that paper got a lot of press, but it was a, you know, it was, uh, it was, it was an important idea. And obviously it was really Gavin's, I was just helping with the astrobiology, that to recognize that, like, yeah, you know, we, we could have been visited a long time ago. There just would be no record. Yeah, it's kinda mind-blowing.
- LFLex Fridman
It's really mind-blowing.
- AFAdam Frank
Yeah.
- LFLex Fridman
And then it's also a good reminder that we've been intelligent, uh, species have been here for a very short amount of time.
- AFAdam Frank
Very short amount of time. Yeah. This is not to say that there was. Like, so, oh, whenever I gave... You know, I, uh, uh, like when I was on Joe Rogan for exactly this paper, and I had to always emphasize, we're not saying there was a Silorian, you know? Um, but we're just saying that if there was. That's why I loved Gavin's question. Gavin's question was just like, how could you tell, right? It was a very beautifully scientific question. Um, that's what we were really showing, is that you really, you know, unless you did a very specific kind of search, which nobody's done so far, that, you know, there would... There's not an obvious way to tell that there, there, there could have been civilizations here earlier on.
- LFLex Fridman
I've actually been reading a lot about ancient civilizations, and it just makes me sad how much of the wisdom of that time is lost-
- AFAdam Frank
Yeah.
- LFLex Fridman
... and, uh, how much guessing is going on, whether it's in, uh, South America, like, what happened in the jungle?
- AFAdam Frank
Yeah. Like the Amazon, like the, the Amazon prob- that was, you know, the conquistadors came and wiped (laughs) everybody out. And especially just even the pl- like the plague may have-
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
... decimated, um, so yeah, how much of that civilization-
- LFLex Fridman
And there's a lot of theories, and, uh, you know, because of archeology only looks at cities, they don't really know the origins of humans.
- AFAdam Frank
Yeah.
- LFLex Fridman
And there's a, there's a lot of really interesting theories in there, of course controversial, and there's a lot of controversial people in, in every discipline, but archeology-
- AFAdam Frank
Mm-hmm.
- LFLex Fridman
... is like a-
- AFAdam Frank
Yeah.
- LFLex Fridman
... it's a fascinating one 'cause we know so little.
- 51:04 – 1:00:32
Alien civilizations
- LFLex Fridman
Uh, go- going back to this, uh, this paper, A New Empirical Constraint on the Prevalence of Technological Species in the Universe, this paper that, uh, expands on the Drake equation, what are some interesting things in this paper?
- AFAdam Frank
Well, so the main thing we were trying to do with this paper is say, look, we have all of this exoplanet data, right? It's gotta be good for something, (laughs) especially since two of the terms that have been nailed down empirically are two terms in the Drake equation. So FsubP, that's the second term, fraction of stars that have planets, and then NsubE, the average number of planets in the habitable zone. Those are the second and third term in the Drake equation. So what that means is all the astronomical terms have been nailed. And so we said like, okay, how do we use this to do something with the Drake equation? And so what we realized is, well, okay, the, we gotta get rid of time. The lifetime thing, we can't say anything about that. Um, but if we let that, if we don't ask how long do they last, but instead ask, uh, what's the probability that there have been any civilizations at all, no matter how long they lasted. I'm not asking whether they exist now or not, I'm just asking in general, um, about probabilities to make a technological civilization anywhere and at any time in the history of the universe. And that we were able to constrain. And so what we found was basically, uh, that the, there have been 10 billion trillion habitable zone planets in the universe. And what that means is that are, those are 10 billion trillion experiments that have been run. Um, and the only way that we're the only time that this is, you know, this whole process from bi- you know, uh, abiogenesis to a civilization has occurred is if every one of those experiments failed, right? So therefore, you could put a, a probability because we called it the pessimism line, right? We don't really know what nature sets for the probability of making intelligent civilizations, right? But we could set a limit when using this. We could say, look, as, if the probability per habitable zone planet is less than 10 to the minus 22, one in 10 billion trillion, then yeah, we're alone. If it's anywhere larger than that, then they're, we're not the first. It's happened somewhere else. And to me that was an ennui- that was mind-blowing. Doesn't tell me there's anybody nearby, the galaxy could be sterile. It just told me that like, you know, uh, unless nature's really against, it has some bias against civilizations, we're not the first time this has happened. This has happened elsewhere over the course of cosmic history.
- LFLex Fridman
10 billion trillion experiments.
- AFAdam Frank
Yeah. That's a lot of experiments.
- LFLex Fridman
That's a lot.
- AFAdam Frank
Right.
- LFLex Fridman
A thousand is a lot.
- AFAdam Frank
Yeah.
- LFLex Fridman
A hundred is a lot.
- AFAdam Frank
Yeah.
- LFLex Fridman
(laughs) I- if, uh, we normal humans saw 100 experiments and, uh, we knew that at least one time, uh, there was a successful human civilization built, I mean, we would say for sure-
- AFAdam Frank
Yeah.
- LFLex Fridman
... in, in a 100 you'll get another one.
- AFAdam Frank
Yeah. Yeah. So that's what I mean, that's why I saw this, you know, these kinds of arguments you have to be careful of what they can do. But what it really, I felt like what this paper showed was that, you know, the burden of proof is now on the pessimists, right? So what, that's why we called it the pessimism line. There's been, you know, throughout history there's been, uh, uh, you know, alien pessimists and alien optimists, and they've been yelling at each other. That's all they had to go with, right? You know, and like with Giordano Bruno in 1600, they burned the guy (laughs) at the stake for being an alien optimist. But nobody really knew what pessimism or optimism meant. This, you know, we sort of thought this was like the Planck length, this was sort of the Planck length of astrobiology, gave you an actual number that, you know, if you could somehow calculate what the probability, uh, you know, of forming a technological civilization was, this thing sort of shows you where the limit is. As, as long as you're above 10 to the minus 22, then you actually, absolutely it has occurred in the, in the, in the history, other civilizations have occurred in the history of the universe.
- LFLex Fridman
So to me at least, the big question is FE, which is basically abiogenesis. How hard is it for life to originate on a planet? 'Cause all the other ones seem-... very likely. Everything seems very likely. The only open question to me-
- AFAdam Frank
Yeah.
- LFLex Fridman
... is like how hard is it for life to originate?
- AFAdam Frank
There's lots of ways to, again, you know, we don't know unless we look. And that, you know, you had Sara Walker on not too long ago. You know, she's very interested in origins of life. Um, uh, so, you know, lots of people are working on this, but I think it's, it's hard looking at the history of the earth. You know, and again, this is, you can do Bayesian arguments on this. Um, but yeah, it, forming life, I don't think is hard. Getting, getting, like, basic biology started I don't think is hard. It's still wild. It's an amazing process that actually I think requires some deep rethinking about how we conceptualize what life is and what life isn't. That's one of the things I like about Sara's work. Um, we're, we're pursuing on a different level, uh, about the life as that on- the only process or the only system that uses information. Um, but still, regardless of all those kinds of details, uh, life is probably easy to make. That's, that's my, that's my gut feeling, you know?
- LFLex Fridman
Yeah, I mean, day by day, this changes f- for me. But I, as you've seen, once you create bacteria, it's- it's- it's off to the races.
- AFAdam Frank
Yeah.
- LFLex Fridman
You're gonna get complex life.
- AFAdam Frank
Yeah.
- LFLex Fridman
A- as long as you have enough time, I mean, that boring billion, and, but I just can't imagine a habitable planet not having a couple of billion to spare-
- AFAdam Frank
Yeah, a couple billion years-
- LFLex Fridman
... of years.
- AFAdam Frank
... to spare. You know, there is a mystery there about why did it take so long, like with the Cambrian explosion, but that may be, again, about these windows, that, like, it couldn't happen until, until the window, the planet, and the, uh, life had evolved together enough that they together kinda opened the window for the, the next step. Um, you know, uh, intelligent life and how long intelligent, you know, civili- technological civilizations, I think there's a big question about how long those last, and how, you know, I'm hopeful, you know. Um, but, uh, but in terms of just like, I think life is absolutely gonna be common in the, you know, pretty common in the universe.
- LFLex Fridman
Yeah, I think it's absolute, like, I, I think, uh, again, if I were to bet everything, uh, e- even in advanced civilizations are common. So the, to me then, the, the only explanation is the L. Our galaxy is a graveyard of civilizations.
- AFAdam Frank
Yeah, 'cause you know, you think about it, we've only been around, I mean, as a tech lot, truly, you know, when we think about in, in, Drake's, uh, definition, you had to have radio telescopes. That's been 100 years. You know, and if we had got another 10,000, 100,000 years of history, that would be w- for us, that'd be pretty amazing, right? Um, but that's still, that wouldn't be long enough to really pop up the number of civilizations in the, in the galaxy. So, you really need it to be, like, hundreds of millions of years, and that raises a question which I am very interested in, which is, how do you even talk about, like the billion-year civilization, right? How do we even begin to hypothesize or think about in any kind of systematic way what happens to a technological civilization across hundreds of millions to a billion years?
- LFLex Fridman
Yeah, like, w- how, how do you even simulate the trajectories that civilizations can take across that kind of timescale?
- AFAdam Frank
Yeah.
- 1:00:32 – 1:12:48
Colonizing Mars
- AFAdam Frank
- LFLex Fridman
Do you think if humans colonize Mars, the dynamic between a civilization on Earth and Mars will be fundamentally different than the dynamic between individual nations on Earth right now? Like, that, that's a thing to load into the simulat- the agent-based simulation-
- AFAdam Frank
Yeah.
- LFLex Fridman
... we're talking about.
- AFAdam Frank
If we settle it, Mars will very quickly wanna become its own nation.
- LFLex Fridman
Well, no, there's already gonna be nations on Mars, that's guaranteed.
- AFAdam Frank
Yeah. There'll be their own-
- LFLex Fridman
The moment you have two million people, one, the moment you have one million people, there's gonna be two tribes.
- AFAdam Frank
Right. Right.
- LFLex Fridman
And then they're going to start fighting.
- AFAdam Frank
Right.
- LFLex Fridman
And the question is, interplanetary fighting, how quickly does that happen, and does it have a different nature to it?
- AFAdam Frank
Uh...
- LFLex Fridman
Because of the distances, you know?
- AFAdam Frank
Uh, are you a fan of The Expanse? Do you, have you watched The Expanse? Great show. 'Cause it's all about the... I highly recommend to everybody, it's based on a series of books that are excellent. It's on Prime, six seasons, and it's basically about the settled solar system. It takes place about 300 years from now and the entire solar system is settled, and it is the best show about interplanetary politics. The first season, actually, um, the journal, what was it? Uh, Foreign, Foreign Affairs, said the best show on TV about politics, it takes place (laughs) is interplanetary. Um, so yeah. I think, you know, human beings being human beings, yes, w- there will be warfare, and there will be conflict. Um, and I don't think it'll be necessarily all that different. Uh, you know, because really, I think within a few hundred years, we will have lots of people in the solar system, and it doesn't even have to be on Mars. We did a paper where we, uh, looked b- based on (laughs) 'cause I always wanted to know about whether what, an idea in The Expanse was really possible. In The Expanse, the, the asteroid belt, what they've done is they have colonized the asteroid belt by hollowing out the asteroids and spinning them up and living em' on, on the inside, right?
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
'Cause they have the Coriolis force. And I thought, like, "Wow, what a cool idea." And when I ran the, uh, blog for NPR, I actually talked to the guys and said, "Did you guys calculate this to see whether it's possible?" Sadly, it's not possible. The rock is just not strong enough that if you tried to spin it up to the speeds you need to get, uh, one-third gravity, which is what I think the minimum you need for human beings, uh, the rock would just fall apart. It would break. But, we came up with another idea, which was that if you take small asteroids, put a giant bag around them, a nanofiber bag, and spin those up, it would inflate the bag, and then even a small, couple of c- uh, kilometer wide asteroid, would s- expand out to, um, you could get like a m- uh, uh, a Manhattan's worth of material inside. So, forget about even colonizing Mars. Space stations, right? Or space habitats with millions of people in them. So anyway, the point is that I think, uh, you know, within a few hundred years, it is not unimaginable that there will be millions, if not billions of people living in the solar system.
- LFLex Fridman
And s- you think most of them will be in space habitats versus on Mars on, on a planetary surface.
- AFAdam Frank
I th- you know, it's a lot easier on some, on some level, right? Depends on how w- like, with nanofabrication and such. But, you know, getting down to gravity well is hard, right? Um, so, you know, there's a certain way in which is a lot of, you know, it's a lot easier to build real estate out of, uh, asteroids. Um, but we'll probably do both. I mean, I think what'll happen is, oh, you know, the next... Should we make it through climate change and nuclear war and all the other, and AI, um, the, the next 1,000 years of human history is the solar system, right? And so, you know, I think we'll settle every nook and cranny we possibly can. And it's, you know, it's a beautiful... What I love about, what's hopeful about it is this idea you're gonna have all of these pockets and, you know, I'm sure there's going to be a Mormon space habitat. (laughs)
- LFLex Fridman
(laughs)
- AFAdam Frank
Like, you know, there's gonna be... Whatever you want. A libertarian space habitat. Everybody's gonna be able to kinda create their... There'll be lots of experiments in human flourishing.
- LFLex Fridman
Mm-hmm.
- AFAdam Frank
And those kinds of experiments will be really useful for us to sort of figure out better ways for us to interact and have maximum flourishing, maximum wellness, maximum democracy, maximum freedom.
- LFLex Fridman
Uh, do you think that's a good backup solution to go out into space sort of to avoid the possibility of humans destroying themselves completely here on Earth?
- AFAdam Frank
Well, I think, you know, I wanna be always careful with that because it, you know, like I said, it's centuries that we're talking about, right?
- LFLex Fridman
Yes.
- AFAdam Frank
Um, so, you know, the, the problem with climate change, you know, and same with nuclear war, it's breathing down our necks now. So it's not a... You know, trying to establish a, a, a, a base on Mars is gonna be so hard that it is not even gonna be close to being self-sufficient for a couple of s- you know, a century at least. So it's not like a backup plan now. Um, you know, we have to solve the problem of climate change. We have to deal with that there's still enough nuclear weapons to really do horri- you know, horrific things to the planet for human beings. Um, so I don't think it's like a backup plan in that way. But I do think, like I said, it's the prize. It's, you know, if we get through this, then we get the entire solar system to sort of play around in and, and experiment with and do really cool things with.
- LFLex Fridman
Well, I think it could be a lot less than a couple of centuries if there's a urgency, like a real urgency, like a catastrophe. Like, uh, maybe a small nuclear war breaks out where it's like, "Holy shit, this is for sure, for sure a bigger one is looming."
- AFAdam Frank
Yeah.
- LFLex Fridman
Maybe, maybe if geopolitically, the war between China and the United States escalates where there's this tension that builds and builds and builds and it becomes more obvious that we need to really, really, really accelerate.
- 1:12:48 – 1:29:13
Search for aliens
- AFAdam Frank
- LFLex Fridman
So as we look out there, according to the Drake equations we dis- just discussed, seems impossible to me that there's not civilizations everywhere. So how do we look at them? This process of SETI.
- AFAdam Frank
I have to put on my scientist hat and just say my gut feeling is that dumb life, so to speak, is common. I am a little agnostic about... I, I, I can see ways in which intelligent civilizations may be sparse.
- LFLex Fridman
Yeah.
- AFAdam Frank
But, but until you know, we gotta go look. It's all, it's all armchair, armchair astronomy.
- LFLex Fridman
So that's, that's from a sort of rigorous scientific pe-
- AFAdam Frank
Yeah.
- LFLex Fridman
... perspective. From my bro science perspective it seems again smoking this, the aforementioned weed, uh, it's-
Episode duration: 3:26:39
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