The following is a conversation with Catherine DeClear, a professor of Planetary Science and

Astronomy at Caltech. Her research is on the surface environments, atmospheres,

and thermochemical histories of the planets and moons in our solar system.

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As a side note, let me say that this conversation and a few others, quite big ones actually,

that are coming up or filmed in a studio where I was trying to outsource some of the work.

Like all experiments, it was a learning experience for me. It had some positives and negatives.

Ultimately, I decided to return back to doing it the way I was doing before, but hopefully

with a team who can help me out and work with me long term. The point is, I will always keep

challenging myself, trying stuff out, learning, growing, and hopefully improving over time.

My goal is to surround myself with people who love what they do, are amazing at it,

and are obsessed with doing the best work of their lives. To me, there's nothing more energizing

and fun than that. In fact, I'm currently hiring a few folks to work with me on very small projects.

If this is something of interest to you, go to lexfreedman.com slash hiring.

That's where I will always post opportunities for working with me. This is the Lex Freedman

podcast, and here is my conversation with Catherine DeCleer. Why is Pluto not a planet anymore?

Does this upset you or has justice finally been served?

So I get asked this all the time. I think all planetary scientists get asked about Pluto,

especially by kids who we just love for Pluto to still be a planet. But the reality is,

when we first discovered Pluto, it was a unique object in the outer solar system, and we thought,

you know, we were adding a planet to the inventory of planets that we had. And then over time,

it became clear that Pluto was not a unique, large object in the outer solar system, that there were

actually many of these. And as we started discovering more and more of them, we realized that the

concept of Pluto being a planet didn't make sense unless maybe we added all the rest of them as

planets. So, you know, you could have imagined actually a different direction that this could

have gone where all the other objects that were discovered in that belt, or at least all the ones,

let's say above a certain size, became planets instead of Pluto being declassified. But we

were now aware of many objects out there in the outer solar system and what's called the Kuiper

Belt that are of the same size, or in some cases even larger than Pluto. So, the declassification

was really just a realization that it was not in the same category as the other planets in

the solar system. And we basically needed to refine our definition in such a way that took

into account that there's this belt of debris out there in the outer solar system of things

with a range of sizes. Is there a hope for clear categorization of what is a planet and not?

Or is it all just gray area? When you study planets, when you study moon satellites of those

planets, is there a line that could be cleanly drawn or is it just a giant mess? This is all

like a fluid, let's say not mess, but it's like fluid of what is a planet, what is a moon of a

planet, what is debris, what is asteroids, all that kind of. So, there are technically clear

definitions that were set down by the IAU, the International Astronomy Union. Is it size related?

Like what are the parameters based on what? So, the parameters are that it has to orbit the sun,

which was essentially to rule out satellites. Of course, this was a not very forward thinking

definition because it technically means that all extra solar planets according to that definition

are not planets. So, it has to orbit the sun. It has to be large enough that its gravity has

caused it to become spherical in shape, which also applies to satellites and also applies to

Pluto. The third part of the definition is the thing that really rules out everything else,

which is that it has to have cleared out its orbital path. And because Pluto orbits in a

belt of material, it doesn't satisfy that stipulation. Why didn't you clear out the path?

It's not big enough to knock everybody out of the way. And this actually is not the first time

it has happened. So, Ceres, when it was discovered, Ceres is the largest asteroid in the asteroid

belt and it was originally considered a planet when it was first discovered and it went through

exactly the same story, history, where people actually realized that it was just one of many

asteroids in the asteroid belt region and then it got declassified to an asteroid and now it's

back to a dwarf planet. So, there is a lot of reclassification. So, to me, as somebody who

studies solar system objects, I just personally don't care my level of interest in something has

nothing to do with what it's classified as. So, my favorite objects in the solar system are all moons

and frequently when I talk about them, I refer to them as planets because to me they are planets.

They have volcanoes. They have geology. They have atmospheres. They're planet like worlds. And so,

the distinction is not super meaningful to me, but it is important just for having a general

framework for understanding and talking about things to have a precise definition.

So, you don't have a special romantic appreciation of a moon versus a planet versus an asteroid. It's

just an object that flies out there and it doesn't really matter what the categorization is. Because

there's movies about asteroids and stuff and then there's movies about the moon, whatever,

it's a really good movie. There's something about moons that's almost like an outlier.

Like, you think of a moon as a thing that's the secret part and the planet is the more vanilla

regular part. None of that. You don't have any of that? No, I actually do. I really, satellites are

the moons are my favorite things in the solar system. And I think part of what you're saying,

I agree from maybe a slightly different perspective, which is from the perspective of

exploration. We've spent a lot of time sending spacecraft missions to planets. We had a mission

to Jupiter. We had a mission to Saturn. We have plenty of missions to Mars and missions to Venus.

I think that exploration of the moons in the outer solar system is the next frontier of

solar system exploration. The belt of debris just real quick. That's out there. Is there something

incredible to be discovered there? Again, we tend to focus on the planets and the moons,

but it feels like there's probably a lot of stuff out there. And it probably,

what is it? It's like a garbage collector from outside of the solar system, isn't it?

Like, doesn't it protect from other objects that kind of fly in and what it just feels like it's

a cool, you know, you know, when you like walk along the beach and look for stuff and like look

for sure. It feels like that's that kind of place where you can find cool, cool, weird things.

I guess in our conversation today, when we think about tools and what science is studying,

is there something to be studied out there? Or we just don't have maybe the tools yet,

or there's nothing to be found? There's absolutely a lot to be found. So the material

that's out there is remnant material from the formation of our solar system. We don't think

it comes from outside the solar system, at least not most of it. But there are so many

fascinating objects out there. And I think what you fit on is exactly right that we just don't

have the tools to study them in detail. But we can look out there and we can see there are

different species of ice on their surface that tells us about, you know, the chemical composition

of the disk that formed our solar system. Some of these objects are way brighter than

they should be, meaning they have some kind of geological activity. People have hypothesized

that some of these objects have subsurface oceans. You could even stretch your imagination and say

some of those oceans could be habitable. But we can't get very detailed information about them

because they're so far away. And so I think if any of those objects were in the inner solar system,

it would be studied intently and would be very interesting. So would you be able to design a

probe in that like very dense debris field, be able to like hop from one place to another?

Is that just outside of the realm of like, how would you even design devices or sensors that

go out there and take pictures and land? Do you have to land to truly understand

a little piece of rock? Or can you understand it from remotely, like fly up close and remotely

observe? You can learn quite a lot from just a flyby. And that's all we're currently capable

of doing in the outer solar system. The New Horizons mission is a recent example, which flew

by Pluto. And then they had searched for another object that was out there in the Kuiper Belt,

any object that was basically somewhere that they could deflect their trajectory to actually

fly by. And so they did fly by another object out there in the Kuiper Belt, and they take pictures

and they do what they can do. And if you've seen the images from that mission of Pluto,

you can see just how much detail we have compared to just the sort of reddish dot

that we knew of before. So you do get an amazing amount of information actually from just essentially

a high speed flyby. It always makes me sad to think about flybys that we might be able to,

we might fly by a piece of rock, take a picture and think, oh, that looks pretty and cool and

whatever and that you could study certain like composition of the surface and so on.

But it's actually teeming with life, and we won't be able to see it at first. And it's sad,

because you know, like when you're on a deserted island, you wave your hands and the

thing flies by and you're trying to get their attention. And they probably do the same, well,

in their own way, bacteria probably, right? But, and we miss it. I don't know,

some reason it makes me, it's the FOMO, it's fear of missing out. It makes me sad that there might

be life out there. And we don't, we're not in touch with it. We're not talking. Yeah. Well, okay.

A sad pause, a Russian philosophical pause. Okay. What are the tools available to us to

study planets and their moons? Oh my goodness, that is such a big question. So among the field

of astronomy, so planetary science broadly speaking, well, it falls kind of at the border of

astronomy, geology, climate science, chemistry, and even biology. So it's kind of on the border

of many things, but part of it falls under the heading of astronomy. And among the things that

you can study with telescopes like solar system moons and planets, the solar system is really

unique in that we can actually send spacecraft missions to the objects and study them in detail.

And so I think that's, that's the kind of type of tool that is that people are most aware of,

this most popularized, these amazing NASA missions that either you fly by the object,

you orbit the object, you land on the object, potentially you can talk about digging into it,

drilling, trying to detect tectonic tremors on its surface. The types of tools that I use are

primarily telescopes. And so I, my background is in astrophysics. And so I actually got into

solar system science from astronomy, not from, you know, a childhood fascination with spacecraft

missions, which is actually what a lot of planetary scientists became planetary scientists

because of childhood fascination with spacecraft missions, which is kind of interesting for me to

talk to people and see that trajectory. I kind of came at it from the fascination with telescopes

angle. So you like telescopes, not rockets, or at least the Earth? When I was a kid, it was looking

at the stars and playing with telescopes that really fascinated me. And that's how I got into this.

But telescopes, it's amazing how much detail and how much information you can get from

telescopes today, you can resolve individual cloud features and watch them kind of shear

out in the atmosphere of Titan, you can literally watch volcanoes on IO change from day to day as

the lava flows expand. So, and then, you know, with spectroscopy, you get compositional information

on all these things. And it's, when I started doing solar system astronomy, I was surprised by

how much detail and how much information you can get even from Earth, and then as well as from orbit

like the Hubble Space Telescope or the James Webb. So with the telescope, you can, I mean,

how much information can you get about volcanoes, about storms, about sort of weather,

just so we kind of get a sense like what a resolution we're talking about.

Well, in terms of resolution, so to, you know, on a given night, if I go and take a picture of

IO and it's volcanoes, you can sometimes see at least a dozen different volcanoes, you can see

the infrared emission coming off of them and resolve them, separate them from one another

on the surface, and actually watch how the heat coming off of them changes with time.

And I think this time variability aspect is one of the big advantages we get from telescopes. So

you send a spacecraft mission there, and you get an incredible amount of information over a very

short time period. But for some science questions, you need to observe something for 30 years, 40

years, like let's say you want to look at the moon Titan, which has one of the most interesting

atmospheres in the solar system. Its orbital period is 29, 30 years. And so if you want to look at

how its atmospheric seasons work, you have to observe it over that long of a time period. And

you're not going to do that with a spacecraft, but you can do it with telescopes.

Can we just zoom in on certain things like, let's talk about IO, which is the moon of Jupiter.

Okay, it's like epic. There's like volcanoes all over the place. From a distance, it's awesome.

So can you tell me about this moon? And you're sort of a scholar of many planets and moons,

but that one kind of stood out to me. So why is that an interesting one?

For so many reasons, but IO is the most volcanically active object in the solar system.

It has hundreds of active volcanoes on it. It has volcanic plumes that go hundreds of kilometers

up above its surface. It puts out more volume of magma per volcano than volcanoes on Earth today.

Okay. But I think to me, the reason that it's most interesting is as a laboratory for understanding

planetary processes. So one of the broad goals of planetary science is to put together a sort of

more general and coherent framework for how planets work in general. Our current framework,

you know, it started out very Earth centric. We start to understand how Earth volcanoes work.

But then when you try to transport that to somewhere like IO that doesn't have an atmosphere,

which makes it has a very tenuous atmosphere, which makes a big difference for how the magma

de gases, for something that's really small, for something that has a different heat source,

for something that's embedded in another object's magnetic field, the kind of intuition we have

from Earth doesn't apply. And so broadly, planetary science is trying to broaden that

framework so that you have a kind of narrative that all you can understand how each planet

became different from every other planet. And I'm already making a mistake. When I say planet,

I mean planets and moons, like I said, I see the moons as planets.

As planets. Yeah. I actually already noticed that you didn't introduce IO as the moon of Jupiter.

You completely, you kind of ignored the fact that Jupiter exists. It's like, let's focus on this.

Yeah. Okay. So, Anne, you also didn't mention Europa, which I think is the,

is that the most famous moon of Jupiter? Is that the one that gets attention because it might have

life? Exactly. Yeah. But to you, IO is also beautiful. What's the difference between volcanoes

on IO versus Earth? You said atmosphere makes a difference. What? Yeah. The heat source plays

a big role. So, many of the moons in the outer solar system are heated from gravitationally by

tidal heating. And I'm happy to describe what that is. Yeah, please. What's tidal? Yes.

So, tidal heating is, it's, if you want to understand and contextualize planets and moons,

you have to understand their heat sources. So, for Earth, we have radioactive decay in our

interior as well as residual heat of formation. But for satellites, tidal heating plays a really

significant role and in particular in driving geological activity on satellites and potentially

making those subsurface oceans in places like Europa and Enceladus habitable. And so, the way

that that works is if you have multiple moons and their orbital periods are integer multiples of one

another, that means that they're always encountering each other at the same point in the orbit. So,

if they were on just random orbits, they'd be encountering each other at random places and

the gravitational effect between the two moons would be canceling out over time. But because

they're always meeting each other at the same point in the orbit, those gravitational interactions

add up coherently. And so, that tweaks them into eccentric orbits. What's the eccentric orbit?

So, eccentric orbit or elliptical orbit, it just means noncircular. So, a deviation from a circular

orbit and that means that for Io or Europa, at some points in their orbit, they're closer to

Jupiter and at some points in their orbit, they're farther away. And so, when they're closer, they're

stretched out in a sense, but literally just not very stretched out, like a couple hundred meters,

something like that. And then when they're farthest away, they're less stretched out. And so, you

actually have the shape of the object deforming over the course of the orbit. And these orbits

are like just a couple of days. And so, that, in the case of Io, that is literally sufficient

friction in its mantle to melt the rock of its mantle. And that's what generates the magma.

That's the source of the time. Okay. So, Europa is, I thought there's like ice and

oceans underneath kind of thing. So, why is Europa not getting a friction?

It is. It's just a little bit farther away from Jupiter. And then, Ganymede is also in the orbital

resonance. So, it's a three object orbital resonance in the Jupiter system. But we have these sorts

of orbital resonances all over the solar system and also in exoplanets. So, for Europa, basically,

because it's farther from Jupiter, the effect is not as extreme, but you do still have heat

generated in its interior in this way. And that may be driving, could be driving hydrothermal

activity at the base of its ocean, which obviously would be a really valuable thing for life.

Cool. So, it's like heating up the ocean a little bit.

Heating up the ocean a little bit and specifically in these hydrothermal vents where we see really

interesting life evolve in the bottom of Earth's oceans.

That's cool. Okay. So, what's Io? What else? So, we know the source is this friction,

but there's no atmosphere. I'm trying to get a sense of what it's like if you and I were to visit

Io. Like, what would that look like? What would it feel like? Is this the entire thing covered in

basically volcanoes? So, it's interesting because there's very little atmosphere. The surface is

actually really cold, very far below freezing on the surface when you're away from a volcano,

but the volcanoes themselves are over a thousand degrees or the magma when it comes out is over

a thousand degrees. But it does come to the surface of the magma? It does, yeah.

In particular places, whoa, that probably looks beautiful. So, it's frozen, not ice. What is

rock? It's really cold rock. And then you just have this, what would that look like with no

atmosphere? Would that, would it be smoke? What does it look like? Is it just magma, like just

red, yellow, like liquidy things? It's black. It's black and red, I guess. Like, think of

the type of magma that you see in Hawaii. So, different types of magma flow in different ways,

for example. So, in somewhere like Io, the magma is really hot and so, it will flow out in sheets

because it has really low viscosity. And I think the lava flows that we've been having in Hawaii

over the past couple years are probably a decent analogy, although Io's magmas, lavas are even

more fluid and faster moving. How fast? Like, what, how fast, like, if you, by the way,

started through the telescope, are you tracking at what time scale? Like, every frame is how

far apart, if you're looking through a telescope. Are we talking about seconds or we're talking about

days, months? When you kind of track, try to get a picture of what the surface might look like,

what's the frequency? So, it depends a little bit on what you want to do, ideally every night.

But you could take a frame every second and see how things are changing. The problem with that

is that for things to change on a one second time scale, you, to actually see something change that

fast, you have to have super high resolution. The spatial resolution we have is a couple hundred

kilometers. And so, things are not changing on those scales over one second unless you have

something really crazy happening. So, if you get, if you get a telescope closer to Io, if you get,

or a camera closer to Io, would you be able to understand something? Is that something of interest

to you? Would you be able to understand something deeper about these volcanic eruptions and how

magma flows and just the, like, the rate of the magmas? Or is it basically enough to have the

kilometer resolution? Do you get a sense? No way. We want to go there. Absolutely. You want to go to Io?

I mean, I don't want to go there personally, but I want to send a spacecraft mission there,

absolutely. Why? Why are you scared? Why am I scared? Oh, you mean you don't...

Oh, like... I don't want to go there as a human. As a human. I want to send a robot there to look

at it, though. This is, again, everybody's discriminating against robots. This is not,

but it's fine. But it's not hospitable to humans in any way, right? So, it's very cold and very hot.

It's very cold. The atmosphere is composed of sulfur dioxide, so you can breathe it. There's no

pressure. I mean, it's kind of all the same things you talk about. One talks about Mars only

worse. The atmosphere is still a thousand times less dense than Mars is. And the radiation environment

is terrible because you're embedded deep within Jupiter's magnetic field. And Jupiter's magnetic

field is full of charged particles that have all come out of Io's volcanoes, actually. So,

Jupiter's magnetic field strips all this material out of Io's atmosphere, and that populates its

entire magnetosphere, and then that material comes back around and hits Io and spreads throughout

the system, actually. It's like Io is the massive polluter of the Jupiter system.

Okay, cool. So, what is studying Io teach you about volcanoes on Earth or vice versa

in the difference of the two? What insights can you mine out that might be interesting in some way?

Yeah, we try to port the tools that we use to study Earth volcanism to Io, and it works to some

extent, but it is challenging because the situations are so different. And the compositions

are really different when you talk about outgassing, you know, Earth volcanoes outgassed primarily

water and carbon dioxide, and then sulfur dioxide is the third most abundant gas. And on Io,

the water and carbon dioxide are not there. Either it didn't form with them or it lost them,

we don't know. And so, the chemistry of how the magma outgasses is completely different.

But the kind of one, to me, most interesting analogy to Earth is that so Io, as I've said,

has these really low viscosity magmas, the lava spreads really quickly across its surface. It can

put out massive volumes of magma in relatively short periods of time. And that sort of volcanism

is not happening anywhere else in the solar system today, but literally every terrestrial

planet and the moon had this, what we call, very effusive volcanism early in their history.

Okay, so this is almost like a little glimpse into the early history of Earth.

Yeah.

Okay, cool. So what are the chances that a volcano on Earth destroys all of human civilization?

Maybe I wanted to sneak in that question.

Yeah, a volcano on Earth.

Do you think about that kind of stuff when you just study volcanoes elsewhere?

Because isn't it kind of humbling to see something so powerful and so hot,

like so unpleasant for humans? And then you realize we're sitting on many of them here?

Right. Yeah, Yellowstone as a classic example. I don't know what the chances are of that happening.

My intuition would be that the chances of that are lower than the chances of us getting wiped out

by some other means. That maybe it'll happen eventually that there'll be one of these massive

volcanoes on Earth, but we'll probably be gone by then by some other means. Not to sound bleak.

That's very comforting. Okay, so can we talk about Europa?

Is there, so maybe can you talk about the intuition, the hope that people have about

life being on Europa? Maybe also, what are the things we know about it?

What are things to you that are interesting about that particular moon of Jupiter? Sure.

Yeah, Europa is, from many perspectives, one of the really interesting places in the solar system

among the solar system moons. So there are a few, there has, there's a lot of interest in looking for

or understanding the potential for life to evolve in the subsurface oceans. I think it's

fairly widely accepted that the chances of life evolving on the surfaces of really anything in

the solar system is very low. The radiation environment is too harsh. And there's, there's

just not liquids on the surface of most of these things. And it's canonically accepted that liquids

are required for life. And so the subsurface oceans, in addition to maybe Titan's atmosphere,

the subsurface oceans of the icy satellites, are one of the most plausible places in the

solar system for life to evolve. Europa and Celadus are interesting because for many of the big

satellites, so Ganymede and Callisto, also satellites of Jupiter, also are thought to have

subsurface oceans. But they are, so they have these ice shells, and then there's an ocean

underneath the ice shell. But on those moons around Ganymede, we think that there's another ice

shell underneath, and then there's rock. And the reason that that is a problem for life is that

your ocean is probably just pure water because it's trapped between two big shells of ice.

So Europa doesn't have this ice shell at the bottom of the ocean, we think. And so the water

and rock are in direct interaction. And so that means that you can basically dissolve a lot of

material out of the rock. You potentially have this hydrothermal activity that's injecting energy

and nutrients for life to survive. And so this rock water interface is considered really important

for the potential habitability. As a smaller side, you kind of said that it's canonically assumed

that light water is required for life. Is it possible to have life in the volcano? I remember

people, it's like a National Geographic program or something kind of hypothesizing that you can

really have life anywhere. So as long as there's a source of heat, a source of energy, do you think

it's possible to have life in a volcano? Like no water? I think anything's possible. I think it's

so water, it doesn't have to be water. That's sort of, you can tell, as you identified, I phrased

that really carefully. It's canonically accepted that because we recognize that, you know, scientists

recognize that we have no idea what broad range of life could be out there. And all we really have

is our biases of life as we know it. But for life as we know it, it's very helpful to have, or even

necessary to have some kind of liquid and preferably a polar solvent that can actually dissolve

molecules, something like water. So the case of liquid methane on Titan is less ideal from that

perspective. But you know, liquid magma, if it stays liquid long enough for life to evolve,

you have a heat source, you have a liquid, you have nutrients. In theory, that checks your three

classic astrobiology boxes. That'd be fascinating. I mean, it'd be fascinating if it's possible to

detect it easily. How would we detect if there is life on Europa? Is it possible to do in a

noncontact way from a distance through telescopes and so on? Or do we need to send robots and do

some drilling? I think realistically, you need to do the drilling. So Europa also has these

long tectonic features on its surface where it's thought that there's potential for water from

the ocean to be somehow making its way up onto the surface. And you could imagine some out there

scenario where there's bacteria in the ocean, it's somehow working its way up through the ice shell,

it's spilling out on the surface, it's being killed by the radiation. But your instrument

could detect some spectroscopic signature of that dead bacterium. But that's, you know,

that's many ifs and assumptions. That's a hope because then you don't have to do that much

drilling you can collect from the surface. Right. Or even I'm thinking even remotely.

Oh, remotely. Yeah. That's sad that there's a single cell civilization living underneath all

that ice trying, trying to get up, trying to get out. So Enceladus gives you a slightly better

chance of that because Enceladus is a moon of Saturn and it's broadly similar to Europa in

some ways. It's an icy satellite, it has a subsurface ocean that's probably in touch with

the rocky interior. But it has these massive geysers at its south pole where it's spewing out

material that appears to be originating all the way from the ocean. And so in that case,

you could potentially fly through that plume and scoop up that material and hope that at the

velocities you'd be scooping it up, you're not destroying any signature of the life you're looking

for. But let's say that you have some ingenuity and can come up with a way to do that, you know,

it potentially gives you a more direct opportunity at least to try to measure those bacteria directly.

Can you tell me a little more on how do you pronounce it? Celas. Enceladus. Enceladus?

Can you tell me a little bit more about Enceladus? Like we've been talking about way too much about

Jupiter. Saturn doesn't get as much love. So what's Enceladus? Is that the most exciting moon of

Saturn? Depends on your perspective. It's very exciting from an astrobiology perspective. I think

Enceladus and Titan are the two most unique and interesting moons of Saturn that definitely

both get the most attention also from the life perspective. So what's the more likely Titan

or Enceladus for life? If you were to bet all your money in terms of like investing,

which to investigate, what are the difference between the two that they're interesting to you?

Yeah, so the potential for life in each of those two places is very different. So Titan is the one

place in the solar system where you might imagine, again, all of this is so speculative, but you

might imagine life evolving in the atmosphere. So from a biology perspective, Titan is interesting

because it forms complex organic molecules in its atmosphere. It has a dense atmosphere. It's

actually denser than Earth's. It's the only moon that has an atmosphere denser than Earth's.

That's cool. It's got tons of methane in it. What happens is that methane gets irradiated,

it breaks up and it reforms with other things in the atmosphere. It makes these complex,

organic molecules and it's effectively doing prebiotic chemistry in the atmosphere.

While it's still freezing cold? Yes. Okay. What would that be like? Would that be pleasant

for humans to hang out there? It's just really cold? There's nowhere in the solar system that

would be pleasant for humans. It would be cold. You couldn't breathe the air.

But colonization wise, if there's an atmosphere, is that a big plus or still a ton of radiation?

Okay. So Titan, that's a really nice feature that the life could be in the atmosphere because

then it might be remotely observable or certainly is more accessible if you visit.

Okay. So what about Enceladus? So that would be still in the ocean.

Right. Enceladus has the advantage, like I said, of spewing material out of its

south pole so you could collect it. But it has the disadvantage of the fact that we don't actually

really understand how its ocean could stay globally liquid over the age of the solar system.

And so there are some models that say that it's going through this cyclical evolution

where the ocean freezes completely and thaws completely and the orbit sort of

oscillates in and out of these eccentricities. And in that case, the potential for life

ever occurring there in the first place is a lot lower because if you only have an ocean for 100

million years, is that enough time? And it also means that might be mass extinction events if

it does occur. Right. And it just freezes. Yes. Again, very sad, man. This is very depressing.

All that slaughter of life elsewhere. How unlikely do you think life is on earth?

So when you look, when you study other planets and you study the contents of other planets,

does that give you a perspective on the origin of life on earth, which again is full of mystery

in itself? Not the evolution, but the origin, the first springing to life,

like from, from nothing to life, from the basic ingredients to life.

I guess another way of asking it is how unique are we?

Yeah, it's a great question. And it's one that just scientifically we don't have an answer to.

We don't even know how many times life evolved on earth if it was only once or if it happened

independently a thousand times in different places. We don't know whether it's happened

anywhere else in the universe, although it feels absurd to believe that we are the only

life that evolved in the entire universe, but it's conceivable. We just have just no

real information. We don't understand really how life came about in the first place on earth.

I mean, so if you look at the Drake equation that tries to estimate how many alien civilizations

are out there, planets have a big part to play in that equation. If you were to bet money

in terms of the odds of origins of life on earth, I mean, this all has to do with how special

and unique is earth. What you land in terms of the number of civilizations has to do with

how unique their rare earth hypothesis is, how rare a special is earth, how rare and special

is the solar system. If you had to bet all your money on a completely unscientific question,

well, no, it's actually rigorously scientific. We just don't know a lot of things in that equation.

There's a lot of mysteries about that, and it's slowly becoming better and better understood

in terms of exoplanets, in terms of how many solar systems are out there where there's planets,

there are earth like planets that's getting better and better understood. What's your sense

from that perspective, how many alien civilizations out there, zero or one plus?

You're right that the equation is being better understood, but you're really only talking about

the first three parameters in the equation or something, how many stars are there,

how many planets per star, and then we're just barely scratching the surface of what fraction

of those planets might be habitable. The rest of the terms in the equation are like,

how likely is life to evolve given habitable conditions? How likely is it to survive all

these things? They're all these huge unknowns. Actually, I remember when I first saw that

equation, I think it was my first year of college, and I thought, this is ridiculous,

this is a common sense that didn't need to give a name and b, just a bunch of unknowns,

it's like putting our ignorance together in one equation, but I've actually, now I understand

this equation, it's not something we ever necessarily have the answer to, it just gives

us a framework for having the exact conversation we're having right now, and I think that's how

it was intended in the first place when it was put into writing was to give people a language

to communicate about the factors that go into the potential for aliens to be out there and for

us to find them. I would put money on there being aliens, I would not put money on us having definitive

evidence of them in my lifetime. Well, definitive is a funny, is a fun word, because my sense is,

this is the saddest part for me, is my sense in terms of intelligent alien civilizations.

I feel like we're so, we're so self obsessed that we literally would not be able to detect them,

even when they're like in front of us, like, like trees could be aliens, but just their

intelligence could be realized on a scale, on a time scale, or physical scale that we're not

appreciating, like trees could be way more intelligent than us, I don't know, it's just

a dumb example, it could be rocks, rock, or it could be things like, I love this, this is

Dawkins memes, it could be that ideas are the, like ideas we have, like where do ideas come from,

where do thoughts come from, maybe thoughts are the aliens, or maybe thoughts is the

actual mechanisms of communication in physics, right, this is like, we think of thoughts as

something that springs up from neurons firing, or where the hell they come from. And now,

what about consciousness, maybe consciousness is the communication, it sounds like ridiculous,

but like, we're so self centered on this space time, communication and physical space,

using like written language, like spoken with audio, on a time scale that's very specific,

on a physical scale that's very specific. So I tend to think that bacteria will probably

recognize, like, like moving organisms will probably recognize, but when that forms itself

into intelligence, most likely it'll be robots of some kind, because we won't be meeting the

origins, we'll be meeting the creations of those intelligences, we just would not be able to

appreciate it. And that's the saddest thing to me, that we, yeah, we're too dumb to see aliens.

Like, we're too, we kind of think like, look at the progress of science, we've accomplished so

much. The sad thing, it could be that we're just like, in the first 0.001% of understanding anything,

it's humbling. I hope that's true, because I feel like we're very ignorant as a species,

and I hope that our current level of knowledge only represents the 0.001% of what we will someday

achieve. That actually feels optimistic to me. Well, I feel like that's easier for us to comprehend

in the space of biology, and not as easy to comprehend in the space of physics, for example,

because we have a sense that like, we have, it like, if you talk to theoretical physicists, they

have a sense that we understand the basic laws that form the nature of reality of our universe.

But so there's much more, like physicists are much more confident. Biologists are like,

this is a squishy mess, we're doing our best. But I would be, it'd be fascinating to see if

physicists themselves would also be humbled by their being, like, what the hell is dark matter

and dark energy? What the hell is the, not just the origin of the, not just the Big Bang, but

everything that happens since the Big Bang. A lot of things that happen since the Big Bang,

we have no ideas about, except basic models of physics. Right, or what happened before the Big

Bang? Yeah, yeah, what happened before, or what's happening inside the Black Hole? Why is there a

Black Hole at the side of our galaxy? Can somebody answer this? A supermassive Black Hole? Nobody

knows how it started. And they seem to be like in the middle of all galaxies. So that could be a

portal for aliens to communicate through consciousness. Okay. All right, back to planets.

What's your favorite, outside of Earth, what's your favorite planet or moon? Maybe outside of

the ones, well, first, have we talked about it already? Or, and then, if we did mention it,

what's the one outside of that? Oh, gosh, I have to come up with another favorite that's not Io?

Oh, Io is the favorite. Oh, absolutely. Why is Io the favorite? I mean, basically everything I've

already said, it's just such an amazing and unique object. But on, I guess, a personal note, it's

probably the object that made me become a planetary scientist. It's the first thing in the solar system

that really deeply captured my interest. And when I started my PhD, I wanted to be an

astrophysicist working on things like galaxy evolution. And sort of slowly, I had done some

projects in the solar system, but Io was the thing that like really caught me into doing

solar system science. Okay, let's, let's leave moons aside. What's your favorite planet?

It sounds like you like moons better than planets. So let's, that's accurate. But the

planets are, are fascinating. I think, you know, I find the planets in the solar system really

fascinating. What I like about the moons is that they, there's so much less that is known,

there's still a lot more discovery space. And the questions that we can ask are still the

bigger questions. Gotcha. Which, you know, I, and maybe I'm being unfair to the planets because

we're still trying to understand things like was there ever life on Mars? And that is a huge

question and one that we've sent numerous robots to Mars to try to answer. So maybe I'm being unfair

to the planets, but there is certainly quite a bit more information that we have about the

planets than the moons. But I mean, Venus is, is a fascinating object. So I like the objects that

lie at the extremes. I think that if we can make a sort of theory or like I've been saying,

framework for understanding planets and moons that can incorporate even the most extreme ones,

then, you know, those are the things that really test your theory and test your understanding.

And so they've always really fascinated me, not so much the nice habitable places like Earth,

but these extreme places like Venus that have sulfuric acid clouds and just incredibly hot and

dense surfaces. And Venus, of course, I love volcanism for some reason. And Venus has, probably

has volcanic activity, definitely has in their recent past, maybe has ongoing today.

What do you make of the news and maybe you can update it in terms of life being discovered

in the atmosphere of Venus? Is that, sorry. Okay. You have opinion, I can already tell you

have opinions. Was that fake news? I got excited. I saw that. What's the, what's the final,

is there a life on Venus? So the detection that was reported was the detection of the molecule

phosphine. And they said that they tried every other mechanism they could think of to produce

phosphine. And they none of no mechanism worked. And then they said, well, we know that life

produces phosphine. And so that was sort of the train of logic. And

I don't personally believe that phosphine was detected in the first place.

Okay. So I mean, this is just one study, but I as a layman, I'm skeptical a little bit

about tools that sense the contents of an atmosphere, like contents of an atmosphere from

remotely and making conclusive statements about life.

Oh, yeah. Well, that connection that you just made, the contents of the atmosphere to the life

is a tricky one. And yeah, I know that that claim received a lot of criticism for

the lines of logic that went from detection to claim of life. Even the detection itself, though,

doesn't, doesn't meet the sort of historical scientific standards of a detection.

The, it was a very tenuous detection and only one line of the species was detected. And a lot of

really complicated data analysis methods had to be applied to even make that weak detection.

Yeah. So it could be, it could be noise, it could be polluted data, it could be all the,

all those things. And so it doesn't have, it doesn't meet the, the level of rigor that you would

hope. But of course, I mean, we're doing our best. And it's clear that the human species are hopeful

to find life. Clearly. Yes. Everyone is so excited about that possibility. All right. Let's, let me

ask you about Mars. So there's a guy named Elon Musk. And he seems to want to take something

called Dogecoin there. First of the month. I'm just kidding about the Dogecoin. I don't even

know what the heck is up with that whole, I think, I think humor has power in the 21st century

in a way to spread ideas in the most positive way. So I love that kind of humor because it makes

people smile, but it also kind of sneaks like a Trojan horse for cool ideas.

You open with humor and you, like the humor is the appetizer and then the main meal is the science

and the engineering. Anyway, do you think it's possible to colonize Mars or other planets in

the solar system? But we're especially looking to Mars. Is there something about planets that

make them very harsh to humans? Is there something in particular you think about? And maybe, you know,

high, like big picture perspective, do you have a hope we do in fact become a multi planetary

species? I do think that if our species survives long enough and we don't wipe ourselves out or

get wiped out by some other means that we will eventually be able to colonize other planets,

I do not expect that to happen in my lifetime. I mean, tourists may go to Mars, tourists,

people who commit years of their life to go into Mars as a tourist may go to Mars.

I don't think that we will colonize it. Is there a sense why it's just too harsh

from an environment to, like it's too costly to build something habitable there for a large

population? I think that we need to do a lot of work and learning how to use the resources that

are on the planet already to do the things we need. So if you're talking about someone going

there for a few months, so we'll back up a little bit. There are many things that make Mars not

hospitable temperature. You can't breathe air, you need a pressure suit, even if you're on the

surface, the radiation environment is, you know, even in all of those things, the radiation

environment is too harsh for the human body. All of those things seem like they could eventually

have technological solutions. The challenge, the real significant challenge to me seems to be the

creation of a self sustaining civilization there. You know, you can bring pressure suits,

you can bring oxygen to breathe, but those are all in limited supply. And if we're going to

colonize it, we need to find ways to make use of the resources that are there to do things like

produce food, produce the air the humans need to keep breathing, just in order to make itself

sustaining, there's a tremendous amount of work that has to be done. And people are working on

these problems. But I think that's going to be a major obstacle in going from visiting where we

can bring everything we need to survive in the short term to actually colonizing. Yeah, I find

that whole project of the human species quite inspiring. These like huge moonshot projects.

Somebody was reading something in terms of the source of food that's that may be the most effective

on Mars is you could farm insects. That's the easiest thing to farm. So we'll be eating like

cockroaches before living on Mars. Because that's the easiest thing to actually

as a source of protein. So growing a source of protein is the easiest thing is insects. I just

imagine this giant for people who are afraid of insects. This is not a pleasant. Maybe you're

not supposed to even think of it that way. It'll be like a cockroach milkshake or something like

that. Right. I wonder if people have been working on the genetic engineering of insects to make them

radiation friendly, or pressure resistant or whatever. What can possibly go wrong?

Radiation resistant. They're already like survived everything. Plus, I took an allergy test in

Austin. So there's everybody's like the allergy levels are super high there. And one of the things,

apparently, I'm not allergic to any insects, except cockroaches. It's hilarious. So maybe

well, I'm going to use that as you know, people use an excuse that I'm allergic to cats to not

have cats. I'm going to use that as an excuse to not go to Mars as one of the first batch of people.

I was going to ask if you had the opportunity when you go.

Yeah, I'm joking about the cockroach thing. I would definitely go. I love challenges.

I love things. I love doing things where the possibility of death is not insignificant

because it makes me appreciate it more. Meditating on death makes me appreciate life.

And when the meditation on death is forced on you because of how difficult the task is,

I enjoy those kinds of things. Most people don't, it seems like. But I love the idea of difficult

journeys for no purpose whatsoever, except exploration, going into the unknown, seeing what

the limits of the human mind and the human body are. It's like, what the hell else is this whole

journey that we're on for? But it could be because I grew up in the Soviet Union, there's a kind of

love for space, like the space race, the Cold War created. I don't know if still it permeates

American culture as much, but especially with the data as a scientist, I think I've

loved the idea of humans striving out towards the stars, always. Like from the engineer

perspective, it's been really exciting. I don't know if people love that as much in America

anymore. I think Elon is bringing that back a little bit, that excitement about rockets and

going out there. So that's hopeful. But for me, I always love that idea. From an alien scientist

perspective, if you were to look back on Earth, is there something interesting you could say

about Earth? How would you summarize Earth? Hitchhiker's Guide to the Galaxy, if you had to

report, write a paper on Earth or a letter, like a one pager, summarizing the contents of the

surface and the atmosphere, is there something interesting? Do you ever take that kind of

perspective on it? I know you like volcanism, so volcanoes, that'll probably be in the report.

I was going to say that's where I was going to go first. There are a few things to say about

the atmosphere, but in terms of the volcanoes, so one of the really interesting puzzles to me

in planetary sciences, so we can look out there and we've been talking about surfaces and volcanoes

and atmospheres and things like that. But that is just this tiny little veneer on the outside of

the planet, and most of the planet is completely inaccessible to telescopes or to spacecraft

missions. You can drill a meter into the surface, but that's still really the veneer.

And one of the cool puzzles is looking at what's going on on the surface and trying to figure out

what's happening underneath, or just any kind of indirect means that you have to study the

interior because you can't dig into it directly, even on Earth, you can't dig deep into Earth.

So from that perspective, looking at Earth, one thing that you would be able to tell from orbit,

given enough time, is that Earth has tectonic plates. So you would see that volcanoes follow

the edges. If you trace where all the volcanoes are on Earth, they follow these lines that trace

the edges of the plates. And similarly, you would see things like the Hawaiian string of volcanoes

that you could infer, just like we did as people actually living on Earth, that the plates are

moving over some plume that's coming up through the mantle. And so you could use that to say,

if the aliens could look at where the volcanoes are happening on Earth and say something about

the fact that Earth has plate tectonics, which makes it really unique in the solar system.

So the other planets don't have plate tectonics? It's the only one that has plate tectonics.

Yeah. What about Io and the friction and all that? That's not plate tectonics. What's the

difference between all this plate tectonics, like another layer of solid rock that moves around

and there's cracks? Exactly. Yeah. So Earth has plates of solid rock sitting on top of a partially

molten layer. And those plates are shifting around. On Io, it doesn't have that. And the

volcanism is what we call heat pipe volcanism. It's the magma just punches a hole through the

crust and comes out on the surface. I mean, that's a simplification, but that's effectively what's

happening through the freezing cold crust. Yes. Very cold, very rigid crust. Yeah.

How does that look like, by the way? I don't think we've mentioned. So the gas that's expelled,

like if we were to look at it, is it like beautiful? Is it like boring? The gas?

Like the whole thing, like the magma punching through the icy? Yes. I'm sure it would be

beautiful. And the pictures we've seen of it are beautiful. You have, so the magma will come out of

the lava, will come out of these fissures. And you have these curtains of lava that are

maybe even a kilometer high. So if you looked at videos, I don't know how many volcano videos

you've looked at on Earth, but you sometimes see a tiny, tiny version of this in Iceland. You see

just these sheets of magma coming out of a fissure when you have this really low

viscosity magma sort of water like coming out at these sheets. And the plumes that come out,

because there's no atmosphere, all the plume molecules are just plume particles where they

end up is just a function of the direction that they left the vent. So they're all following

ballistic trajectories. And you end up with these umbrella plumes. You don't get these sort of

complicated plumes that you have on Earth that are occurring because of how that material is

interacting with the atmosphere that's there. You just have these huge umbrellas. And it's

been hypothesized actually that the atmosphere is made of sulfur dioxide and that you could have

these kind of ash particles from the volcano and the sulfur dioxide would condense onto these

particles. And you'd have sulfur dioxide snow coming out of these volcanic plumes.

And that's not much light though, right? So you wouldn't be able to, like it would

make a good, it would not make a good Instagram photo because you have to, would you see the snow?

Sure. There's light. It depends. Oh, okay. So you could, you could, okay. Depends what angle

you're looking at it, where the sun is, all the things like that. You know, the sunlight is much

weaker, but it's still there. It's still there. And how big is IO in terms of gravity? Is it smaller?

Is it a pretty small moon? It's quite a bit smaller than Earth anyway. It's smaller than Earth. Okay.

Okay, cool. So they float, float up for a little bit. So the floats, wow, they, yeah,

no, you're right. That would be, that would be, that would be gorgeous. What else about Earth

is interesting besides the volcano. So plate tectonics, I didn't realize that that was the

unique element of a planet in the solar system. Because that, I wonder what, I mean, we experience

that as human beings, it's quite painful because of earthquakes and all those kinds of things, but

I wonder if there's nice features to it. Yeah. So coming back to habitability again,

things like tectonics and plate tectonics are, are thought to play an important role in the

surface being habitable. And that's because you have a way of recycling materials. So

if you have a stagnant surface, everything, you know, you use up all the free oxygen,

everything reacts until you no longer have reactants that life can extract energy from.

And so if nothing's changing on your surface, you kind of reach this stagnation point.

But something like plate tectonics recycles material, you bring up new fresh material from

the interior, you bring down material that's up on the surface, and that can kind of refresh your

nutrient supply in a sense, or the sort of raw materials that the surface has to work with.

So from a kind of astrobiologist perspective, looking at Earth, you would see that recycling of

material because the plate tectonics, you would also see how much oxygen is in Earth's atmosphere.

And between those two things, you would identify Earth as a reasonable candidate for a habitable

environment, in addition to, of course, the, you know, pleasant temperature and liquid water.

But the abundance of oxygen and the, the plate tectonics both play a role as well.

And also see like tiny dots, satellites flying around.

Well, sure, yes.

I wonder if they would be able to, I really think about that, like if they, if aliens were to visit,

and would they really see humans as the thing they should be focusing on?

I think it would take a while, right?

Because it's so obvious that that should, because there's like so much incredible,

in terms of biomass, humans are a tiny, tiny, tiny fraction.

There's like ants.

They would probably detect ants, right?

Or they probably would focus on the water and the fish.

Because there's like a lot of what, I don't, I was surprised to learn that there's more species

on land than there is in the sea.

Like there's 90, I think 90 to 95% of the species are on land.

Or on land?

Not in the sea.

Not in the sea.

I thought like there's so much going on in the sea, but no, the, the variety that like the

branches created by evolution, apparently, it's probably a good answer from an evolutionary

biology perspective, why land created so much diversity, but it did.

So like the sea, there's so much not known about the sea, about the oceans, but it's not,

it's not diversity friendly, what can I say?

It needs to, it needs to improve its diversity.

Looking at the sea.

Do you think the aliens would come?

I mean, the first thing they would see is, I suppose, are cities, assuming that they had some

idea of what a natural world looked like, they would see cities and say these don't belong.

Which of these many species created these?

Yeah, I mean, there's, I, if I were to guess, it would, it's a good question.

I don't know if you do this when you look at the telescope, whether you look at geometric

shapes, like if it's good, because to me, like hard corners, like what do we think is engineered?

Things that are like, have kind of straight lines and corners and so on, they would probably

detect those in terms of buildings would stand out to them, because that's, that goes against

the basic natural physics of the world.

But I don't know if the electricity and lights and so on, it could be, I honestly, it could be

the plate tectonics, it could be like, that, the like the volcanoes, that'd be, okay, that's

a source of heat, and then they would focus, they might literally, I mean, depending on how

alien life forms are, they might notice the microorganisms before they notice the big,

like notice the and before the elephant, because like, there's a lot more of them,

depending what they're measuring device, we think like size matters, but maybe with

their tools of measurement, they would look for quantity versus size.

Like why focus on the big thing, focus on the thing that there's a lot of, and when they see

humans, depending on their measurement devices, they might see, we're made up of billions of

organisms, like the fact that we have, we're very human set, we think we're one organism,

but that may not be the case.

They might see, in fact, they might also see like a human city, as one organism.

Like, what is this thing that like, clearly, this organism gets aroused at night, because

the lights go on, and then, and then it like, it sleeps during the day.

I don't know, like, the what perspective you take on the city.

Is there something interesting about earth or other planets in terms of weather patterns?

So we talked a lot about, what is the reason for that?

So we talked a lot about volcanic patterns.

Is there something else about weather that's interesting, like storms, or variations in

temperature, all those kinds of things?

Yeah, so there's sort of, every planet and moon has a kind of interesting and unique

weather pattern, and those weather patterns are really, we don't have a good understanding of

them. We don't even have a good understanding of the global circulation patterns of many of these

atmospheres, why the storm systems occur.

So the composition and occurrence of storms and clouds and these objects is another one of these

kind of windows into the interior that I was talking about with surfaces.

One of these ways that we can get perspective and what the composition is at the interior and

how the circulation is working.

So circulation will bring some species up from deeper in the atmosphere of the planet to some

altitude that's a little bit colder, and that species will condense out and form a cloud at that

altitude, and we can detect, in some cases, what those clouds are composed of.

And looking at where those occur can tell you how the circulation cells are, whether the atmospheric

circulation is, say, coming up at the equator and going down at the poles, or whether you have

multiple cells in the atmosphere. And I mean, Jupiter's atmosphere is just insane. There's

so much going on. You look at these pictures and there's all these vortices and anti vortices,

and you have these different bands that are moving in opposite directions that may be giving you

information about the deep in the atmosphere, physically deep properties of Jupiter's interior

and circulation.

What are these vortices? What's the basic material of the storms?

It's condensed molecules from the atmosphere, so ammonia ice particles. In the case of Jupiter,

it's methane ice, in the case of, let's say, Uranus and Neptune, and other species. You can

kind of construct a chemical model for which species can condense where, and so you see a cloud at a

certain altitude within the atmosphere, and you can make a guess at what that cloud is made of,

and sometimes measure it directly, and different species make different colors as well.

Oh, cool. Ice storms. Okay. I mean, the climate of Uranus has always been fascinating to me because

it orbits on its side, and it has a 42 year orbital period. And so, you know, with Earth,

our seasons are because our equator is tipped just a little bit to the plane that we orbit in. So

sometimes the sunlight's a little bit above the equator, and sometimes it's a little bit below

the equator. But on Uranus, it's like for 10 years, the sunlight is directly on the North Pole,

and then it's directly on the equator, and then it's directly on the South Pole. And it's actually

kind of amazing that the atmosphere doesn't look crazier than it does. But understanding how,

taking, again, like one of these extreme examples, if we can understand why that atmosphere behaves

in the way it does, it's kind of a test of our understanding of how atmosphere is.

So like heats up one side of the planet for 10 years, and then freezes it the next,

like, and that you're saying should probably lead to some chaos. And it doesn't.

The fact that it doesn't tells you something about the atmosphere. So atmospheres have a

property that surfaces don't have, which is that they can redistribute heat a lot more effectively.

Right. So they're a stabilizing, like self regulating aspect to them,

that they're able to deal with extreme conditions. But predicting how that complex system

unrolls is very difficult, as we know, about predicting the weather on Earth even.

Oh my goodness. Even with a little variation we have on Earth.

You know, people have tried to put together global circulation models. You know, we've

done this for Earth. People have tried to do these for other planets as well. And it is a really hard

problem. So Titan, for example, like I said, it's one of the best studied atmospheres in the solar

system. And people have tried to make these global circulation models and actually predict what's

going to happen moving into sort of the next season of Titan. And those predictions have

ended up being wrong. And so then, you know, I don't know, it's always exciting when a prediction

is wrong, because it means that there's something more to learn, like your theory wasn't sufficient.

And then you get to go back and learn something by how you have to modify the theory to make it

fit. I'm excited by the possibility of one day there'll be for various moons and planets, there'll

be like news programs reporting the weather with the fake confidence of like as if you can predict

the weather. We talked quite a bit about planets and moons. Can we talk a little bit about asteroids?

For sure. What is, what's an asteroid and what kind of asteroids are there?

So the asteroids, let's talk about just the restricted to the main asteroid belt, which is the

region, it's a region of debris basically between Mars and Jupiter. And the, these sort of belts of

debris throughout the solar system, the outer solar system, you know, the Kuiper belt that we

talked about the asteroid belt, as well as certain other populations where they accumulate,

because they're gravitationally more favored, are remnant objects from the origin of the

solar system. And so one of the reasons that we are so interested in them, aside from potentially

the fact that they could come hit earth, but scientifically, it's, it gives us a window into

understanding the composition of the material from which earth and the other planets formed,

and how that material was kind of redistributed over the, the history of the solar system.

So the asteroids, one could classify them in two different ways. Some of them are ancient objects,

so they accreted out of the, the sort of disk of material that the whole solar system formed out

of, and have kind of remained ever since more or less the same. They've probably collided with each

other, and we see all these collisional fragments. And you can actually look and, based on their

orbits, say, you know, like these 50 objects originated as the same object, you can see them

kind of dynamically moving apart after some big collision. And so some of them are these ancient

objects maybe that have undergone collisions. And then there's this other category of object that

is the one that I personally find really interesting, which is remnants of objects

that could have been planets. So early on, a bunch of potential planets accreted that we call

planetesimals, and they formed, and they formed with a lot of energy, and they had enough time to

actually differentiate. So some of these objects differentiated into cores and mantles and crusts.

And then they were subsequently disrupted in these massive collisions. And they, now we have

these fragments. We think fragments floating around the asteroid belt that are like bits of mantle,

bits of core, bits of crust, basically. So it's like puzzle pieces that you might be able to stitch

together. Or I guess it's all, it's all mixed up. So you can't stitch together the original planet

candidates. Or is that possible to try to see if they kind of, I mean, there's too many, there's

too many objects in there. I think that there are cases where people have, have kind of looked at

objects. And by looking at their orbits, they say these objects should have originated together,

but they have very different compositions. And so then you can hypothesize maybe they were different

fragments of differentiated objects. But one of the really cool things about this is, you know,

we've been talking about getting clues into the interiors of planets. We've never seen a planetary

core or deep mantle directly. Some mantle material comes up on our surface and then we can see it.

But, you know, in sort of in bulk, we haven't seen these things directly. And these asteroids

potentially give us a chance to like look at what our own core and mantle is like, or at least

would be like if it had been also floating through space for a few billion years and getting

irradiated and all that. But it's, it's a cool potential window or like analogy into the interior

of our own planet. Well, how do you begin studying some of these asteroids? What, if you were to put

together a study, like what are the interesting questions to ask that are a little bit more

specific? Do you find a favorite asteroid that could be tracked and try to try to track it

through telescopes? Or do you, is it has to be, you have to land on those things to study it?

So when it comes to the asteroids, there's so many of them. And the big pictures or the big

questions are answered. So some questions can be answered by zooming in in detail on individual

objects, but mostly you're trying to do a statistical study. So you want to look at

thousands of objects, even hundreds of thousands of objects, and figure out what their composition

is and look at, you know, how many big asteroids there are of this composition versus how many

small asteroids of this other composition and put together these kind of statistical properties of

the asteroid belt. And those properties can be directly compared with the results of simulations

for the formation of the solar system. What do we know about the surfaces of asteroids or the

contents of the insides of asteroids? And what are still open questions? So I would say that we don't

know a whole lot about their compositions. Most of them are small. And so you can't study them

in such detail with telescopes as you could, you know, a planet or moon. And at the same time,

because there are so many of them, you could send a spacecraft to a few. But you can't really like

get a statistical survey with spacecraft. And so a lot of what we, a lot of what has been done

comes down to sort of classification. You look at how bright they are, you look at whether they're

red or blue, simply, you know, whether their spectrum is sloped towards long wavelengths or

short wavelengths. There are certain, if you point a spectrograph at their surfaces, there are

certain features you can see. So you can tell that some of them have silicates on them.

And but these are the sort of, they're pretty basic questions. We're still trying to classify

them based on fairly basic information in kind of combination with our general understanding of

the material the solar system formed from. And so you're sort of, you come, you're coming in with

prior knowledge, which is that you more or less know what the materials are the solar system formed

from. And then you're trying to classify them into these categories. There's still a huge amount of

room for, for understanding them better. And for understanding how their surfaces are changing

in the space environment. Is it hard to land on an asteroid? Is this, is this a dumb question?

It feels like it would be quite difficult to actually operate a spacecraft in such a dense

field of debris. Oh, the asteroid belt, there's a ton of material there, but it's actually not

that dense. It is mostly open space. So, so mentally do picture like mostly open space with,

with some rocks. The problem is some of them are not thought to be solid. So some of these asteroids,

especially these, these core mantle fragments, you can think of as sort of solid like a planet.

But some of them are just kind of aggregates of material, we call them rubble piles. And so

there's not necessarily. Might look like a rock. But do a lot of them have kind of clouds around

them, like a dust cloud thing? Or like, do you know what you're stepping on when you try to land on

it? Like what, what are we supposed to be visualizing here? There's like very few of water,

right? There's some water in the outer part of the asteroid belt, but they're not quite like

comets. Okay. In the, in the sense of having clouds around them, there are some crazy asteroids

that do become active like comets. That's the whole other category of thing that we don't

understand. But their surfaces, I mean, we have visited some, you can, you know, find pictures

that spacecraft have taken of them. We've actually scooped up material off of the surface of some

of these objects. We're bringing it back to analyze it in the lab. And there's a mission

that's launching next year to land on one of these supposedly core fragment objects to try to

figure out what the heck it is and what's going on with it. But the surfaces, you know, they're,

they're, you can picture a solid surface with some little grains of sand or pebbles on it

and occasional boulders, maybe some fine dusty regions, dust kind of collecting in certain places.

But is there this, do you worry about this? Is there any chance that one of these

fellows destroys all of human civilization by an asteroid kind of colliding with something,

changing its trajectory and heading its way towards Earth? That is definitely possible.

And it doesn't even have to necessarily collide with something and change its trajectory.

We're not tracking all of them. We can't track all of them yet. You know, there's still

a lot of them. People are, people are tracking a lot of them and we are doing our best to track

more of them. But there are a lot of them out there and it would be potentially catastrophic

if one of them impacted Earth. Have you, are you aware of this Apophis object?

So there's an asteroid near Earth objects called Apophis that people thought had a

decent probability of hitting Earth in 2029 and then potentially again in 2036. So they did a

lot of studies. It's not actually going to hit Earth, but it is going to come very close. It's

going to be visible in the sky in a relatively dark, I mean, not even that dark, probably not

visible from Los Angeles, but, and it's going to come a tenth of the way between the Earth and the

Moon. It's going to come closer apparently than some geosynchronous communication satellites.

Oh, wow.

So that is a close call, but people have studied it and then apparently are very confident it's

not actually going to hit us, but it wasn't.

I'm going to have to look into this because I'm very sure, I'm very sure what's going to happen

if an asteroid actually hits Earth, that the scientific community and government

will confidently say that we have nothing to worry about, it's going to be a close call.

And then last minute, they'll be like, there was a miscalculation.

They're not lying. It's just like the space of possibilities because it's very difficult to

track these kinds of things. And there's a lot of kind of, there's complexities involved to this.

There's a lot of uncertainties that just something tells me that human civilization will end with,

we'll see it coming. And then last minute there'll be a oops, like we'll see it coming and we'll

be like, no, it's just, it's just threatening, but no problem, no problem. And last minute it'll

be like, oops, there was a miscalculation and then it's all over in a matter of like a week.

But we're just very positive and optimistic today. Is there any chance that Bruce Willis

can save us in the sense that from what you know about asteroids, is there something that

you can catch them early enough to change volcanic eruptions, right?

Sort of drill, put a nuclear weapon inside and break up the asteroid or change its trajectory?

There is potential for that if you catch it early enough in advance. I think in theory if you knew

five years in advance,

depending on the objects and how close with how much you would need to deflect it,

you could deflect it a little bit. I don't know that it would be sufficient in all cases.

And this is definitely not my specific area of expertise, but my understanding is that

there is something you could do. But it also how you would carry that out depends a lot on

the properties of the asteroid. If it's a solid object versus a rubble pile, so let's say you

planted some bomb in the middle of it and it blew up, but it was just kind of a pile of

material anyway, and then that material comes back together and then you kind of just have the same

thing. Presumably its trajectory would be altered, but it's... It's like Terminator 2 when it's like

the thing that just like you shoot it and it splashes and then comes back together. It would

be very useless. That's fascinating. And but what's fascinating, I've gotten a lot of hope

from watching SpaceX rockets that land. There's so much... It's like, oh wow, from an AI perspective,

from a robotics perspective, wow, we can do a hell of an amazing job with control.

And but then we have an understanding about surfaces here on Earth. We can map up a lot

of things. I wonder if we can do that some kind of detail of being able to have that same level

of precision in landing on surfaces with as wide of a variety as asteroids have. So be able to

understand the exact properties of the surface and be able to encode that into whatever rocket

that lands. Sufficiently to... I presume humans, unlike the movies, humans would likely get in

the way. Like it should all be done by robots. Like land, drill, place the explosive, that should

all be done through control through robots. And then you should be able to dynamically adjust to

the surface. The flip side of that for a robotics person, I don't know if you've seen these. It's

been very heartbreaking. Somebody, I know well, Russ Tedrick at MIT led the DARPA Robotics Challenge

team for the Humanoid Robot Challenge. For DARPA, I don't know if you've seen videos of robots on

two feet falling. But you're talking about millions, several years of work with some of the most

brilliant roboticists in the world, millions of dollars. And the final thing is a highlight video

on YouTube of robots falling. But they had a lot of trouble with uneven surfaces. That's basically

what you have to do with the challenge involves you're mostly autonomous with some partial human

communication. But that human communication is broken up. Like you don't get a, you get a noisy

channel. So you can, humans can, which is very similar to what it would be like in humans remotely

operating a thing on an asteroid. And so with that, robots really struggle. There's some hilarious,

painful videos of like a robot not able to like open the door. And then it tries to open the door

without like, it misses the handle and in doing so like falls. I mean, it's, it's painful to watch.

So like that there's that. And then there's SpaceX. So I have hope from SpaceX. And then I have less

hope from by Peter Robotics. But it's fun. It's fun to kind of imagine. And I think the planetary

side of it comes into play and understanding the surfaces of these asteroids more and more.

That, you know, forget sort of destruction of the human civilization. It'd be cool to have like

spacecraft just landing on all these asteroids to study them at scale. And being able to figure

out dynamically what, you know, whether it's a rubble pile or whether it's a solid objects.

Like, do you see that kind of future of science, maybe 100, 200, 300 years from now, where there's just

robots expanding out through the solar system, like sensors, essentially, some of it taking

pictures from a distance, some of them landing, just exploring and giving us data. Because it

feels like we're working with very little data right now. Sure, I, I do see exploration going

that way. I think the way that NASA is currently, or historically has been doing missions is putting

together these, these really large missions that do a lot of things and are extremely well tested

and have a very low rate of failure. But now that these sort of CubeSat technologies are becoming

easier to build, easier to launch, they're very cheap. And, you know, NASA is getting

involved in this as well. There's, there's a lot of interest in these missions that are

relatively small, relatively cheap, and just do one thing. So you can really optimize it to,

to just do this one thing. And maybe you could build 100 of them and send them to different

asteroids. And they would just collect this one piece of information from each asteroid.

It's a kind of different, more distributed way of doing science, I guess. And there's a ton of

potential there. I agree. Let me ask you about objects or one particular object from outside

our solar system. We don't get to study many of these, right? They don't, we don't get stuff that

just flies in out of nowhere from outside the solar system and flies through. Apparently there's been

two recently in the past few years. One of them is Amua Moa. What are your thoughts about Amua Moa?

So fun to say. Could it, could it be space junk from a distant alien civilization,

or is it just a weird shaped comet? I like the way that's phrased. So Amua Moa is,

is a fascinating object. Just the fact that we have started discovering things that are coming

in from outside our solar system is amazing and can, can start to study them. And now that we have

seen some, we can design now kind of thinking in advance. The next time we see one, we will be much

more ready for it. We will know which telescopes we want to point at it. We will have explored

whether we could even launch a fast turnaround mission to actually like get to it before it leaves

the solar system. In terms of Amua Moa, yeah, it's for an object in our solar system, it's really

unusual in two particular ways. One is the dimensions that we don't see natural things

in our solar system that are kind of long and skinny. We see the things we see in our solar

system don't deviate from spherical by that much. And then that it showed these strange properties

of accelerating as it was leaving the solar system, which was not understood at first.

So, in terms of the alien space junk, you know, as a scientist, I cannot rule out that possibility.

I have no evidence to the contrary. However, see, you're saying there's a chance.

I cannot, I cannot as a scientist honestly say that I can rule out that it's alien space junk.

However, I see the kind of alien explanation as following this, the Sagan's extraordinary claims

require extraordinary evidence. If you are going to actually claim that something is aliens,

you need to carefully evaluate, one needs to carefully evaluate the other options

and see whether it could just be something that we know exists that makes sense. In the case of

Amua Mua, there are explanations that fit well within our understanding of how things work.

So, there are a couple, there are two hypotheses for what it could be made of. They're both basically

just ice shards. In one case, it's a nitrogen ice shard that came off of something like Pluto

in another solar system. That Pluto got hit with something and broke up into pieces and one of

those pieces came through our solar system. In the other scenario, it's a bit of a failed solar

system. So, our solar system formed out of a collapsing molecular cloud. Sometimes those

molecular clouds are not massive enough and they sort of collapse into bits, but they don't actually

form a solar system, but you end up with these kind of chunks of hydrogen ice, apparently.

And so, one of those chunks of hydrogen ice could have got ejected and passed through our

solar system. So, both cases explain these properties in about the same way. So, those

ices will sublimate once they've passed the sun. And so, as they're moving away from the sun, you

have the hydrogen or nitrogen ice sublimating off the sunward part of it. And so, that is

responsible for the acceleration. The shape also, because you have all this ice sublimating off the

surface, if you take something, the analogy that works pretty well here is for a bar of soap.

Your bar of soap starts out sort of close to spherical, at least from a physicist's perspective.

And as you use it over time, you eventually end up with this long, thin shard, because it's been

just by sort of weathering, as we would call it. And so, in the same way, if you just sublimate

material off of one of these ice shards, it ends up long and thin, and it ends up accelerating

out of the solar system. And so, given that these properties can be reasonably well explained that

way, you know, we should be extremely skeptical about attributing things to aliens.

See, the reason I like to think that it's aliens is because it puts a lot of priority on us not

being lazy, and we need to catch this thing next time it comes around. I like the idea that there

are objects, not like, it almost saddens me. They come out of the darkness really fast,

and just fly by and go and leave. It just seems like a wasted opportunity not to study them.

It's like, it's the easiest way to do space travel outside of the solar system,

is having the things come to us. I like that way of putting it.

And it would be nice to just land on it. And first of all, really importantly,

detect it early, and then land on it with a really nice spacecraft, and study the hell out of it.

And, you know, if there's a chance it's aliens, alien life, it just feels like such a cheap

way, inexpensive way, to get information about alien life or something interesting that's out

there. And I'm not sure if an ice shard from another planetary system will be interesting,

but it very well could be. It could be totally new sets of materials. It could be,

tell us about composition of planets we don't quite understand. And it's just a nice one,

especially in the case of a more and more, I guess it was pretty close to Earth. It would have been

nice to, you know, let's say, don't go there, they come to us. I don't know. That's what makes me,

that's what makes me quite a sad. It's a missed opportunity.

Well, yeah, and whether you think it's aliens or not, it's a missed opportunity, but, you know,

we weren't prepared, and we will be prepared for the next ones. And as, so there's been a movement

in astronomy more towards what's called time domain astronomy, so kind of monitoring the whole

sky all the time at all wavelengths, that's kind of the goal. And so we expect to detect many more

of these in the future, even though these were the first two we saw, our potential to detect them

is only increasing with time. And so there will be more opportunities. And, you know, based on these

two, we now can actually sit and think about what we'll do when the next one shows up.

I also, what it made me realize, I know I didn't really think through this, but it made me realize

if there is alien civilizations out there, the thing we're most likely to see first would be

space junk, my stupid understanding of it. And the second would be really dumb kind of,

you could think of maybe like relay nodes or something, objects that you need to have a whole

lot of for particular purposes of like space travel and so on, like speed limit signs or

something, I don't know, whatever we have on earth, a lot of that's dumb. It's not alien,

aliens and themselves, it's like artifacts that are useful to the engineering in the

systems that are engineered by alien civilizations. So like, it would, we would see a lot of stuff

in terms of setting, in terms of looking for alien life and trying to communicate with it,

maybe we should be looking not for like smart creatures or systems to communicate with,

maybe we should be looking for artifacts or even as dumb as like space junk.

It just kind of reframed my perspective of like, what are we looking for as science?

Because there could be a lot of stuff that doesn't have intelligence but gives us really strong signs

that there's somewhere is life or intelligent life. And yeah, that made me kind of, I know it

might be dumb to say, but reframe the kind of thing that we should be looking for. Yeah, it's,

so the benefit of looking for intelligent life is that we perhaps have a better chance of recognizing

it. Yeah, we couldn't necessarily recognize what an alien stop sign look like. That's true.

And maybe, you know, the theorists are the people who sort of model and try to understand

slow system objects are pretty good at coming up with models for anything. I mean,

it may be a mua mua was a stop sign, but we're clever enough that we could come up with some

physical explanations for it. And then, you know, we all want to go with the simplest possible,

we all want to believe the sort of most skeptical possible explanation. And so we missed it because

we're too good at coming up with alternate explanations for things. And it's such an

outlier, such a rare phenomena that we can't, we can't study, you know, 100 or 1000 of these

objects, we have to we had just one. And so the science almost destroys the possibility of

something special being there. It's like a Johnny I've this design of Apple, I don't know if you

know who that is, he's the lead designer, he's the person who designed the iPhone and all the major

things. And he talked about he's brilliant on my favorite humans on earth, and one of the best

designers in the history of earth. He talked about like when he had this origins of an idea,

like in his baby stages, he would not tell Steve Jobs, because Steve would usually like

trample all over it. He would say this is dumb idea. And so I sometimes think of the scientific

community in that sense, because the the weapon of the scientific method is so strong at its best,

that it sometimes crushes the out of the box outlier evidence. You know, we don't get a lot

of that evidence, because we don't have we're not lucky enough to have a lot of evidence. So we

have to deal with just special cases. And special cases could present an inkling of something much

bigger. But the scientific method user tramples all over and it's hard to know what to do with that,

because the scientific method works. But at the same time, every once in a while, it's like a

balance. You have to do 99% of the time you have to do like scientific rigor. But every once in a

while, this is not you saying me saying smoke some weed and sit back and think, I wonder,

you know, it's the Joe Rogan thing, it's entirely possible that it's alien space junk.

Anyway, yeah, I think so I completely agree. And I think that most scientists do speculate

about these things. It's just at what point do you act on those things? So you're right that

the scientific method has inherent skepticism. And for the most part, that's a good thing,

because it means that we're not just believing crazy things all the time. But it's an interesting

point that requiring that high level of rigor occasionally means that you will miss

something that is truly interesting, because you needed to verify it three times, and it

wasn't verifiable. I also think like when you communicate with the general public,

I think there's power in that 1% speculation of just demonstrating authenticity as a human

being as a curious human being. I think too often, I think this is changing, but I saw,

I've been quite disappointed, my colleagues throughout 2020 with the coronavirus, there's

too much speaking from authority, as opposed to speaking from curiosity. There's some of the most

incredible science has been done in 2020, especially on the virology biology side.

And the kind of being talked down to by scientists is always really disappointing to me,

as opposed to inspiring, like the things we there's a lot of uncertainty about the coronavirus.

But we know a lot of stuff. And we speak from scientists from various disciplines speak from

data in the face of that uncertainty. And we're curious, we don't know what the hell is going

on. We don't know if this virus is going to evolve, evolve, mutate. We don't know if this virus or the

next one might, you know, might destroy all human civilization. You can't speak with certain, in fact,

you know, I was on a survey paper about masks. Something I don't talk much about, because

I don't like politics. But we don't know if masks work. But there's a lot of evidence to show that

they work for this particular virus. The transmission of the virus is fascinating, actually. The

biomechanics of the way viruses spread is fascinating. If it wasn't destructive, it would be beautiful.

And we don't know, but it's inspiring to apply the scientific method to the best of our ability,

but also to show that you don't always know everything, and to perhaps not about the virus

as much, but about other things speculate. What if, you know, what if it's the worst case and the best

case? And because that's ultimately what we are, descendants of apes that are just curious about

the world around us. Yeah, I'll just add to that, not on the topic of masks, but on the topic of

curiosity. That's, I mean, I think that's astronomy and planetary sciences, a field are a little are

unique because for better and for worse, they don't directly impact humanity. So, you know,

we're not studying virology to prevent transmission of, you know, illness amongst humans. We're not

characterizing volcanoes on earth that could destroy cities. We, and it really is a more curious

and in my opinion, playful scientific field than many. So, for better and worse, we can kind of

afford to pursue some of the speculation more because human lives are not in danger if we

speculate a little bit too freely and get something wrong. Yeah, definitely. In the space of AI, I am

worried that we're sometimes too eager, speaking for myself to like flip the switch to on just to

see like what happens. Maybe sometimes we want to be a little bit careful about that because bad

things might happen. Is there books or movies in your life long ago or recently that were inspiring

and had an impact on you that you would recommend? Yeah, absolutely. So many that just don't know

where to start with it. So, I love reading. I read obsessively. I've been reading fiction and a little

bit of nonfiction, but mostly fiction obsessively since I was a child and just never stopped. So,

I have some favorite books. None of them are easy reading. So, I definitely, I mean, I recommend them

for somebody who likes an intellectual challenge in the books that they read. So, maybe I should

go chronologically. I have at least three. I'm not going to go through 50 here. Yeah, I'd love to

also like maybe ideas that you took away from what you mentioned. Yeah, yeah, why they were so

compelling to me. One of the first books that really captured my fascination was Nabokov's book

Pale Fire. Are you familiar with it? So, I read it actually for a class. It's one of the few books

I've ever read for a class that I actually really liked. And the book is, it's in some sense a puzzle.

He's a brilliant writer, of course. But the book is like, it's formatted like a poem. So,

there's an introduction, a very long poem, and footnotes. And you get partway through it before

realizing that the whole thing is actually a novel unless you sort of read up on it going in. But

the whole thing is a novel and there's a story that slowly reveals itself over the course of all of

this and kind of reveals this just fascinating character, basically, and how his mind works in

this story. The idea of a novel also being a kind of intellectual puzzle and something that slowly

reveals itself over the course of reading was really fascinating to me. And I have since found a lot

more writers like that. You know, contemporary example that comes to mind is Kazuo Ishiguro,

who's pretty much all of his books are like slow reveals over the course of the book and like

nothing much happens in the books, but you keep reading them because you just want to know like

what the reality is that he's slowly revealing to you. The kind of discovery oriented reading,

maybe. What's the second one? Perhaps my favorite writer is Renier Maria Rilke.

Are you familiar with him? No, also not familiar. You're hitting ones, I mean, I know in the book

of Well, but I've never read Pale Fire. But Rilke, I've never, I know it's a very difficult read.

I know that much. Yeah, right. All of these are difficult reads. I think I just,

I read for in part for an intellectual challenge. But Rilke, so he wrote one thing that might be

characterizable as a novel, but he wrote a lot of poetry. I mean, he wrote this series of poems

called The Duino Elegies that were very impactful for me personally, just emotionally, which actually,

it kind of ties in with astronomy in that there's there's a sense, you know, in which we're all

going through our lives alone. And there's just this sense of kind of profound loneliness in the

existence of every individual human. And I think I was drawn to astronomy in part because the sort

of vast spaces, the kind of loneliness and desolateness of space made the sort of internal

loneliness feel okay. In a sense, it like gave companionship. And that's how I feel about Rilke's

poetry. He turns the kind of desolation and loneliness of human existence into something

joyful and almost meaningful. Yeah, there's something about melancholy. I don't know about

Rilke in general, but like contemplating the melancholy nature of our of the human condition that

makes it okay. I got gentle from an engineering perspective, think that there is so much loneliness

we haven't explored within ourselves yet. And that's my hope is to build AI systems that help us

explore our own loneliness. I think that's kind of what love is. And friendship is somebody who in a

very small way helps us explore our own loneliness, like they listen, we connect like two lonely creatures,

connect for time. And it's like, oh, like acknowledge that we exist together, like for a brief time.

But in a somewhat shallow way, I think relative to how much it's possible to truly connect as two

consciousnesses. So AI might be able to help on that on that front. So what's the third one?

Actually, you know, I hadn't realized until this moment, but it's yet another one of these kind of

slow reveal books. It's a contemporary Russian, I think Russian American writer named Olga Grushin,

G R U S H I N. And she wrote this just phenomenal book called The Dream Life of Sukhanov that I

read this year, maybe it was last year for the first time. And it's just a really beautiful,

this one you could call a character study, I think, of a Russian father coming to terms with

himself and his own past, as he potentially slowly loses his mind.

Slow reveal. Slow reveal.

Well, that's apparent from the beginning. I hope I don't think it's a spoiler.

I don't think it's a spoiler. Decline into madness. Spoiler alert. So all of these are really heavy.

I don't know. I just, I don't have anything lighter to recommend. Ishii grows the light

version of this. Okay. Well, heavy has a certain kind of beauty to it in itself. Is there advice

you would give to a young person today that looks up to the stars and wonders what the heck they

want to do with their life? So career, science, life in general. You've for now chosen a certain

kind of path of curiosity. What insights do you draw from that that you can give us advice to others?

I think for somebody, I would not presume to speak to giving people advice on life and

humanity overall, but for somebody thinking of being a scientist. So there are a couple of things,

one sort of practical thing, which is career wise, I hadn't appreciated this going into science, but

you need to, so the questions you're working on and the techniques you use are both

of very high importance, maybe equal importance for being happy in your career.

If there are questions you're interested in, but the techniques that you need to use to do them

are tedious for you, then your job is going to be miserable, even if the questions are inspiring.

So you have to find, but if the techniques that you use are things that excite you,

then your job is fun every day. So for me, I'm fascinated by the solar system and I love telescopes

and I love doing data analysis, playing with data from telescopes, coming up with new ways to use

telescopes. And so that's where I have found that mesh. But if I was interested in the

dynamical evolution of the solar system, how the orbits of things evolve, then I would need to do

a different type of work that I would just not find as appealing and so it just wouldn't be a good

fit. And so it sort of seems like an unromantic thing to have to think about the techniques

being the thing you want to work on also, but it really makes a profound difference for,

I think, your happiness and your scientific career.

I think that's really profound. It's like the thing, the menial tasks. If you enjoy those,

that's a really good sign that that's the right path for you. I think David Foster Wallace said

that the key to life is to be unboreable. So basically, everything should be exciting. I

don't think that's feasible, but you should find an area where everything is exciting,

I mean, depending on the day, but you can find the joy in everything, not just the big exciting

chronicle things that everyone thinks is exciting, but the details, the repetitive stuff, the

menial stuff, the stuff that takes years, the stuff that involves a lot of failure,

and all those kinds of things that you find that enjoyable. That's actually really profound to focus

on that. Because people talk about dreams and passion and goals and so on, the big thing,

but that's not actually what takes you there. It takes you there as every single day,

putting in the hours, and that's what actually makes up life is the boring bits. If the boring bits

aren't boring, then that's an exciting life. Because when you were talking so romantically

and passionately about IO, I remember the poem by Robert Frost. So let me read the poem and ask

what your opinion is. It's called Fire and Ice. Oh yeah, I could almost recite this from memory.

Some say the world will end in fire, some say in ice. From what I've tasted of desire,

I hold with those who favor fire. But if I had to perish twice, I think I know enough of hate

to say that for destruction, ice is also great and with suffice. So let me ask,

if you had to only choose one, would you choose the world to end in fire, in volcanic eruptions,

in heat, and magma, or in ice frozen over? Fire or ice? Fire.

Excellent choice. I've always been a fan of chaos and the idea of things just

slowly getting cold and stopping and dying is just so depressing to me. So much more depressing than

things blowing up or burning and they're getting covered by a lava flow. Somehow the activity of

it endows it with more meaning to me, maybe. I've just now had this vision of you in action films

where you're walking away without looking back and there's explosions behind you and you just got

and you put on shades and then it goes to credits. So, Catherine, this was awesome. I think your

work is really inspiring. The kind of things we'll discover about planets in the next few

decades is super cool and I hope, I know you said there's probably not life in one of them,

but there might be and I hope we discover just that. And perhaps even on Io, within the volcanic

eruptions, there's a little creature hanging on that we'll one day discover. Thank you so much

for wasting all your valuable time with me today. It was really awesome. Yeah, likewise. Thank you

for having me here. Thanks for listening to this conversation with Catherine de Cleer and thank you

to Fundurize, Blinkist, ExpressVPN, and Magic Spoon. Check them out in the description to support

this podcast. And now, let me leave you with some words from Carl Sagan. Untightened, the molecules

that have been raining down like mona from heaven for the last four billion years might still be

there, largely unaltered, defrozen, awaiting for the chemists from Earth. Thank you for listening

and hope to see you next time.