Katherine de Kleer: Planets, Moons, and Asteroids in Our Solar System

Lex Fridman (01:59.040)

And then over time, it became clear that Pluto was not a unique, large object in the outer

Katherine de Kleer (02:04.980)

solar system, that there were actually many of these.

Lex Fridman (02:08.960)

And as we started discovering more and more of them, we realized that the concept of Pluto

Katherine de Kleer (02:12.600)

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

Lex Fridman (02:18.960)

So you could have imagined actually a different direction that this could have gone where

Katherine de Kleer (02:22.240)

all the other objects that were discovered in that belt, or at least all the ones, let's

Lex Fridman (02:26.800)

say, above a certain size, became planets instead of Pluto being declassified.

Lex Fridman (02:33.400)

But we're now aware of many objects out there in the outer solar system and what's called

Katherine de Kleer (02:37.920)

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

Lex Fridman (02:44.640)

So the declassification was really just a realization that it was not in the same category

Lex Fridman (02:50.480)

as the other planets in the solar system.

Lex Fridman (02:52.640)

And we basically needed to refine our definition in such a way that took into account that

Katherine de Kleer (02:57.420)

there's this belt of debris out there in the outer solar system of things with a range

Katherine de Kleer (03:03.120)

of sizes.

Katherine de Kleer (03:05.080)

Is there a hope for clear categorization of what is a planet and not, or is it all just

Lex Fridman (03:10.840)

gray area?

Katherine de Kleer (03:11.900)

When you study planets, when you study moons, satellites of those planets, is there lines

Lex Fridman (03:18.080)

that could be cleanly drawn or is it just a giant mess?

Katherine de Kleer (03:20.960)

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

Katherine de Kleer (03:27.120)

is a moon of a planet, what is debris, what is asteroids, all that kind of...

Lex Fridman (03:32.600)

So there are technically clear definitions that were set down by the IAU, the International

Katherine de Kleer (03:38.440)

Astronomy Union.

Lex Fridman (03:41.640)

Is it size related?

Lex Fridman (03:42.640)

Like what are the parameters based on?

Lex Fridman (03:44.440)

So the parameters are that it has to orbit the sun, which was essentially to rule out

Katherine de Kleer (03:49.560)

satellites.

Katherine de Kleer (03:50.560)

Of course, this was a not very forward thinking definition because it technically means that

Katherine de Kleer (03:53.880)

all extrasolar planets according to that definition are not planets.

Lex Fridman (03:58.020)

So it has to orbit the sun.

Katherine de Kleer (04:00.340)

It has to be large enough that its gravity has caused it to become spherical in shape,

Lex Fridman (04:05.760)

which also applies to satellites and also applies to Pluto.

Katherine de Kleer (04:08.280)

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

Lex Fridman (04:11.680)

is that it has to have cleared out its orbital path.

Lex Fridman (04:15.860)

And because Pluto orbits in a belt of material, it doesn't satisfy that stipulation.

Lex Fridman (04:21.560)

Why didn't you clear out the path?

Katherine de Kleer (04:22.840)

It's not big enough to knock everybody out of the way.

Lex Fridman (04:26.560)

And this actually is not the first time it has happened.

Lex Fridman (04:29.060)

So Ceres, when it was discovered, Ceres is the largest asteroid in the asteroid belt,

Lex Fridman (04:33.440)

and it was originally considered a planet when it was first discovered.

Lex Fridman (04:36.760)

And it went through exactly the same story, history, where people actually realized that

Katherine de Kleer (04:42.920)

it was just one of many asteroids in the asteroid belt region, and then it got declassified

Katherine de Kleer (04:47.180)

to an asteroid, and now it's back to a dwarf planet.

Lex Fridman (04:50.160)

So there is a lot of reclassification.

Lex Fridman (04:52.100)

So to me, as somebody who studies solar system objects, I just personally don't care.

Katherine de Kleer (04:59.840)

My level of interest in something has nothing to do with what it's classified as.

Lex Fridman (05:04.460)

So my favorite objects in the solar system are all moons, and frequently when I talk

Lex Fridman (05:08.420)

about them, I refer to them as planets because to me they are planets.

Katherine de Kleer (05:12.400)

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

Lex Fridman (05:17.080)

And so the distinction is not super meaningful to me, but it is important just for having

Katherine de Kleer (05:22.540)

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

Lex Fridman (05:28.260)

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

Katherine de Kleer (05:34.340)

It's just an object that flies out there and it doesn't really matter what the categorization

Lex Fridman (05:38.260)

is.

Katherine de Kleer (05:39.260)

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

Lex Fridman (05:45.300)

whatever, it's a really good movie.

Katherine de Kleer (05:48.780)

There's something about moons that's almost like an outlier.

Katherine de Kleer (05:55.580)

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

Katherine de Kleer (06:03.980)

regular part.

Lex Fridman (06:04.980)

None of that?

Lex Fridman (06:05.980)

You don't have any of that?

Lex Fridman (06:06.980)

No, I actually do.

Katherine de Kleer (06:07.980)

I really, satellites are, the moons are my favorite things in the solar system.

Katherine de Kleer (06:11.220)

I think part of what you're saying, I agree from maybe a slightly different perspective,

Katherine de Kleer (06:17.340)

which is from the perspective of exploration, we've spent a lot of time sending spacecraft

Lex Fridman (06:22.460)

missions to planets.

Katherine de Kleer (06:23.740)

We had a mission to Jupiter, we had a mission to Saturn, we have plenty of missions to Mars

Lex Fridman (06:27.260)

and missions to Venus.

Katherine de Kleer (06:28.500)

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

Lex Fridman (06:33.220)

solar system exploration.

Katherine de Kleer (06:35.580)

The belt of debris, just real quick, that's out there.

Lex Fridman (06:39.400)

Is there something incredible to be discovered there?

Katherine de Kleer (06:42.140)

Again, we tend to focus on the planets and the moons, but it feels like there's probably

Lex Fridman (06:47.500)

a lot of stuff out there and it probably, what is it?

Lex Fridman (06:51.880)

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

Katherine de Kleer (06:56.860)

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

Katherine de Kleer (07:02.060)

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

Katherine de Kleer (07:08.500)

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

Katherine de Kleer (07:13.820)

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

Katherine de Kleer (07:20.580)

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

Lex Fridman (07:24.140)

or there's nothing to be found?

Lex Fridman (07:26.860)

There's absolutely a lot to be found.

Lex Fridman (07:28.340)

So the material that's out there is remnant material from the formation of our solar system.

Lex Fridman (07:32.500)

We don't think it comes from outside the solar system, at least not most of it.

Lex Fridman (07:38.660)

But there are so many fascinating objects out there and I think what you fit on is exactly

Lex Fridman (07:44.740)

right that we just don't have the tools to study them in detail.

Lex Fridman (07:48.780)

But we can look out there and we can see there are different species of ice on their surface

Katherine de Kleer (07:53.100)

that tells us about, you know, the chemical composition of the disk that formed our solar

Katherine de Kleer (07:58.100)

system.

Katherine de Kleer (07:59.100)

Some of these objects are way brighter than they should be, meaning they have some kind

Katherine de Kleer (08:03.060)

of geological activity.

Lex Fridman (08:04.340)

People have hypothesized that some of these objects have subsurface oceans.

Katherine de Kleer (08:08.040)

You could even stretch your imagination and say some of those oceans could be habitable.

Lex Fridman (08:12.460)

But we can't get very detailed information about them because they're so far away.

Lex Fridman (08:16.980)

And so I think if any of those objects were in the inner solar system, it would be studied

Lex Fridman (08:21.500)

intently and would be very interesting.

Lex Fridman (08:24.060)

So would you be able to design a probe in that like very dense debris field, be able

Lex Fridman (08:30.100)

to like hop from one place to another?

Katherine de Kleer (08:32.780)

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

Lex Fridman (08:37.980)

that go out there and take pictures and land?

Lex Fridman (08:42.260)

Do you have to land to truly understand a little piece of rock or can you understand

Lex Fridman (08:47.200)

it from remotely, like fly up close and remotely observe?

Katherine de Kleer (08:52.580)

You can learn quite a lot from just a flyby and that's all we're currently capable of

Lex Fridman (08:56.780)

doing in the outer solar system.

Katherine de Kleer (08:58.540)

The New Horizons mission is a recent example which flew by Pluto and then they had searched

Katherine de Kleer (09:05.300)

for another object that was out there in the Kuiper Belt, any object that was basically

Katherine de Kleer (09:10.260)

somewhere that they could deflect their trajectory to actually fly by.

Lex Fridman (09:13.900)

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

Lex Fridman (09:18.500)

and they do what they can do.

Lex Fridman (09:19.860)

And if you've seen the images from that mission of Pluto, you can see just how much detail

Katherine de Kleer (09:25.220)

we have compared to just the sort of reddish dot that we knew of before.

Lex Fridman (09:29.060)

So you do get an amazing amount of information actually from just essentially a high speed

Katherine de Kleer (09:33.980)

flyby.

Katherine de Kleer (09:34.980)

It always makes me sad to think about flybys that we might be able to, we might fly by

Katherine de Kleer (09:41.260)

a piece of rock, take a picture and think, oh, that looks pretty and cool and whatever.

Lex Fridman (09:46.020)

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

Lex Fridman (09:49.820)

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

Lex Fridman (09:55.780)

And it's sad.

Katherine de Kleer (09:56.780)

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

Katherine de Kleer (10:00.300)

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

Lex Fridman (10:05.460)

own way, bacteria probably, right?

Lex Fridman (10:07.820)

But and we miss it.

Katherine de Kleer (10:10.100)

I don't know, some reason it makes me, it's the FOMO, it's fear of missing out.

Katherine de Kleer (10:16.380)

It makes me sad that there might be life out there and we don't, we're not in touch with

Katherine de Kleer (10:23.060)

it.

Lex Fridman (10:24.060)

We're not talking.

Katherine de Kleer (10:25.060)

Yeah.

Lex Fridman (10:26.060)

Well, okay.

Katherine de Kleer (10:27.060)

A sad pause, a Russian philosophical pause.

Lex Fridman (10:32.540)

Okay.

Lex Fridman (10:33.540)

What are the tools available to us to study planets and their moons?

Lex Fridman (10:36.900)

Oh my goodness.

Katherine de Kleer (10:38.660)

That is such a big question.

Lex Fridman (10:41.520)

So among the field of astronomy, so planetary science broadly speaking, well, it falls kind

Katherine de Kleer (10:47.620)

of at the border of astronomy, geology, climate science, chemistry, and even biology.

Lex Fridman (10:53.860)

So it's kind of on the border of many things, but part of it falls under the heading of

Katherine de Kleer (10:57.820)

astronomy.

Lex Fridman (10:58.820)

And among the things that you can study with telescopes, like solar system moons and planets,

Katherine de Kleer (11:04.560)

the solar system is really unique in that we can actually send spacecraft missions to

Lex Fridman (11:09.660)

the objects and study them in detail.

Lex Fridman (11:11.540)

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

Katherine de Kleer (11:15.580)

aware of, that's most popularized, these amazing NASA missions that either you fly by the object,

Katherine de Kleer (11:22.420)

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

Lex Fridman (11:27.620)

it, drilling, trying to detect tectonic tremors on its surface.

Katherine de Kleer (11:35.060)

The types of tools that I use are primarily telescopes and so I, my background is in astrophysics

Lex Fridman (11:42.140)

and so I actually got into solar system science from astronomy, not from, you know, a childhood

Katherine de Kleer (11:47.700)

fascination with spacecraft missions, which is actually what a lot of planetary scientists

Katherine de Kleer (11:52.300)

became planetary scientists because of childhood fascination with spacecraft missions, which

Katherine de Kleer (11:56.400)

is kind of interesting for me to talk to people and see that trajectory.

Lex Fridman (12:00.500)

I kind of came at it from the fascination with telescopes angle.

Lex Fridman (12:03.460)

So you like telescopes, not rockets, or at least when I was a kid it was looking at the

Katherine de Kleer (12:08.540)

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

Lex Fridman (12:14.180)

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

Lex Fridman (12:21.260)

telescopes today.

Katherine de Kleer (12:22.700)

You can resolve individual cloud features and watch them kind of sheer out in the atmosphere

Lex Fridman (12:29.860)

of Titan.

Katherine de Kleer (12:30.860)

You can literally watch volcanoes on Io change from day to day as the lava flows expand.

Lex Fridman (12:38.620)

So and then, you know, spectroscopy, you get compositional information on all these things

Lex Fridman (12:43.460)

and it's, when I started doing solar system astronomy, I was surprised by how much detail

Lex Fridman (12:51.100)

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

Katherine de Kleer (12:55.740)

like the Hubble Space Telescope or the James Webb.

Lex Fridman (12:59.580)

So with the telescope, you can, I mean, how much information can you get about volcanoes,

Katherine de Kleer (13:06.420)

about storms, about sort of weather, just so we kind of get a sense, like what a resolution

Lex Fridman (13:13.720)

we're talking about?

Katherine de Kleer (13:15.460)

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

Katherine de Kleer (13:20.020)

picture of Io and its volcanoes, you can sometimes see at least a dozen different volcanoes.

Katherine de Kleer (13:26.420)

You can see the infrared emission coming off of them and resolve them, separate them from

Katherine de Kleer (13:30.180)

one another on the surface and actually watch how the heat coming off of them changes with

Katherine de Kleer (13:36.300)

time.

Lex Fridman (13:37.300)

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

Lex Fridman (13:41.740)

So you send a spacecraft mission there and you get an incredible amount of information

Lex Fridman (13:45.860)

over a very short time period.

Lex Fridman (13:47.580)

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

Katherine de Kleer (13:53.480)

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

Katherine de Kleer (13:57.780)

atmospheres in the solar system.

Lex Fridman (14:00.540)

Its orbital period is 29, 30 years.

Lex Fridman (14:04.620)

And so if you want to look at how its atmospheric seasons work, you have to observe it over

Lex Fridman (14:09.700)

that long of a time period.

Lex Fridman (14:11.300)

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

Katherine de Kleer (14:15.420)

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

Katherine de Kleer (14:20.100)

Jupiter.

Lex Fridman (14:21.100)

Right.

Katherine de Kleer (14:22.100)

Okay.

Lex Fridman (14:23.100)

It's so big.

Katherine de Kleer (14:24.100)

There's like volcanoes all over the place.

Lex Fridman (14:27.380)

It's from a distance.

Katherine de Kleer (14:30.260)

It's awesome.

Lex Fridman (14:31.260)

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

Lex Fridman (14:37.700)

but that one kind of stood out to me.

Lex Fridman (14:40.140)

So why is that an interesting one?

Katherine de Kleer (14:42.340)

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

Lex Fridman (14:47.620)

It has hundreds of active volcanoes on it.

Katherine de Kleer (14:50.500)

It has volcanic plumes that go hundreds of kilometers up above its surface.

Lex Fridman (14:56.140)

It puts out more volume of magma per volcano than volcanoes on Earth today.

Lex Fridman (15:03.180)

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

Lex Fridman (15:10.160)

planetary processes.

Lex Fridman (15:12.780)

So one of the broad goals of planetary science is to put together a sort of more general

Lex Fridman (15:18.700)

and coherent framework for how planets work in general.

Katherine de Kleer (15:24.580)

Our current framework, you know, it started out very Earth centric.

Lex Fridman (15:27.660)

We start to understand how Earth volcanoes work.

Lex Fridman (15:30.540)

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

Katherine de Kleer (15:35.140)

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

Katherine de Kleer (15:41.540)

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

Katherine de Kleer (15:44.940)

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

Katherine de Kleer (15:49.140)

Earth doesn't apply.

Lex Fridman (15:50.220)

And so broadly, planetary science is trying to broaden that framework so that you have

Katherine de Kleer (15:56.540)

a kind of narrative that you can understand how each planet became different from every

Lex Fridman (16:01.260)

other planet.

Lex Fridman (16:02.700)

And I'm already making a mistake.

Lex Fridman (16:04.060)

When I say planet, I mean planets and moons.

Katherine de Kleer (16:06.300)

Like I said, I see the moons as planets.

Lex Fridman (16:08.340)

As planets.

Katherine de Kleer (16:09.340)

Yeah.

Lex Fridman (16:10.340)

I actually already noticed that you didn't introduce Io as the moon of Jupiter.

Katherine de Kleer (16:14.620)

You completely, you kind of ignored the fact that Jupiter exists.

Lex Fridman (16:19.300)

It's like, let's focus on this.

Katherine de Kleer (16:21.900)

Yeah.

Lex Fridman (16:22.900)

Okay.

Katherine de Kleer (16:23.900)

So, and you also didn't mention Europa, which I think is the, is that the most famous moon

Lex Fridman (16:28.780)

of Jupiter?

Lex Fridman (16:29.780)

Is that the one gets attention because it might have life?

Lex Fridman (16:33.660)

Exactly.

Katherine de Kleer (16:34.660)

Yeah.

Lex Fridman (16:35.660)

But to you, Io is also beautiful.

Lex Fridman (16:37.980)

What's the difference between volcanoes on Io versus Earth?

Lex Fridman (16:41.900)

You said atmosphere makes a difference.

Lex Fridman (16:44.980)

What the heat source plays a big role.

Lex Fridman (16:48.500)

So many of the moons in the outer solar system are heated from gravitationally by tidal heating.

Lex Fridman (16:55.860)

And I'm happy to describe what that is or, yeah, please, what's tidal?

Lex Fridman (17:00.540)

Yes.

Lex Fridman (17:01.540)

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

Lex Fridman (17:07.740)

you have to understand their heat sources.

Lex Fridman (17:10.660)

So for Earth, we have radioactive decay in our interior as well as residual heat of formation.

Lex Fridman (17:16.580)

But for satellites, tidal heating plays a really significant role and in particular

Katherine de Kleer (17:21.300)

in driving geological activity on satellites and potentially making those subsurface oceans

Lex Fridman (17:27.380)

in places like Europa and Enceladus habitable.

Lex Fridman (17:31.040)

And so the way that that works is if you have multiple moons and their orbital periods are

Katherine de Kleer (17:37.500)

integer multiples of one another, that means that they're always encountering each other

Katherine de Kleer (17:42.380)

at the same point in the orbit.

Lex Fridman (17:46.420)

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

Lex Fridman (17:50.220)

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

Lex Fridman (17:55.020)

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

Katherine de Kleer (18:00.160)

interactions add up coherently.

Lex Fridman (18:02.860)

And so that tweaks them into eccentric orbits.

Lex Fridman (18:06.100)

What's an eccentric orbit?

Lex Fridman (18:08.020)

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

Katherine de Kleer (18:12.980)

a circular orbit.

Lex Fridman (18:13.980)

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

Lex Fridman (18:19.180)

and at some points in their orbit, they're farther away.

Lex Fridman (18:22.340)

And so when they're closer, they're stretched out in a sense, but literally just not very

Katherine de Kleer (18:29.580)

stretched out, like a couple hundred meters, something like that.

Lex Fridman (18:32.240)

And then when they're farthest away, they're less stretched out.

Lex Fridman (18:35.220)

And so you actually have the shape of the object deforming over the course of the orbit.

Lex Fridman (18:40.140)

And these orbits are like just a couple of days.

Lex Fridman (18:42.620)

And so that, in the case of Io, that is literally sufficient friction in its mantle to melt

Lex Fridman (18:49.300)

the rock of its mantle.

Lex Fridman (18:50.900)

And that's what generates the magma.

Lex Fridman (18:52.840)

That's the source of the magma.

Katherine de Kleer (18:54.660)

Yeah.

Lex Fridman (18:55.660)

Okay.

Lex Fridman (18:56.660)

So why is, so Europa is, I thought there was like ice and oceans underneath kind of thing.

Lex Fridman (19:03.200)

So why is Europa not getting the friction?

Katherine de Kleer (19:05.380)

It is, it's just a little bit farther away from Jupiter.

Lex Fridman (19:07.820)

And then Ganymede is also in the orbital resonance.

Lex Fridman (19:10.740)

So it's a three object orbital resonance in the Jupiter system.

Lex Fridman (19:14.900)

But we have these sorts of orbital resonances all over the solar system and also in exoplanets.

Lex Fridman (19:20.700)

So for Europa, basically because it's farther from Jupiter, the effect is not as extreme,

Lex Fridman (19:25.620)

but you do still have heat generated in its interior in this way.

Lex Fridman (19:29.500)

And that may be driving, could be driving hydrothermal activity at the base of its ocean,

Lex Fridman (19:34.940)

which obviously would be a really valuable thing for life.

Katherine de Kleer (19:38.780)

Cool.

Lex Fridman (19:39.780)

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

Katherine de Kleer (19:42.100)

Heating up the ocean a little bit.

Lex Fridman (19:43.620)

And specifically in these like hydrothermal vents where we see really interesting life

Katherine de Kleer (19:48.580)

evolve in the bottom of Earth's oceans.

Lex Fridman (19:51.060)

That's cool.

Katherine de Kleer (19:52.060)

Okay.

Lex Fridman (19:53.060)

So what's Io, what else?

Lex Fridman (19:55.440)

So we know the source is this friction, but there's no atmosphere.

Katherine de Kleer (19:59.740)

I'm trying to get a sense of what it's like if you and I were to visit Io, like what would

Katherine de Kleer (1:00:01.380)

is made of sulfur dioxide, and that you could have these kind of ash particles from the

Katherine de Kleer (1:00:07.700)

volcano and the sulfur dioxide would condense onto these particles, and you'd have sulfur

Katherine de Kleer (1:00:13.940)

dioxide snow coming out of these volcanic plumes.

Lex Fridman (1:00:18.300)

And there's not much light, though, right?

Lex Fridman (1:00:21.380)

So you wouldn't be able to, like, it would not make a good Instagram photo, because you

Lex Fridman (1:00:25.180)

have to, would you see the snow?

Katherine de Kleer (1:00:28.140)

Sure.

Lex Fridman (1:00:29.140)

There's light.

Katherine de Kleer (1:00:30.140)

It depends.

Lex Fridman (1:00:31.140)

Oh, okay.

Lex Fridman (1:00:32.140)

So you could, okay.

Katherine de Kleer (1:00:33.140)

It depends what angle you're looking at it, where the sun is, all the things like that.

Katherine de Kleer (1:00:36.380)

You know, the sunlight is much weaker, but it's still there.

Lex Fridman (1:00:38.580)

It's still there.

Lex Fridman (1:00:41.180)

And how big is Io in terms of gravity?

Lex Fridman (1:00:44.180)

Is it smaller?

Lex Fridman (1:00:45.180)

Is it a pretty small moon?

Lex Fridman (1:00:47.780)

It's quite a bit smaller than Earth anyway.

Katherine de Kleer (1:00:49.980)

It's smaller than Earth.

Lex Fridman (1:00:50.980)

Okay.

Katherine de Kleer (1:00:51.980)

Okay.

Lex Fridman (1:00:52.980)

Cool.

Lex Fridman (1:00:53.980)

So they float up for a little bit.

Lex Fridman (1:00:54.980)

So it floats.

Katherine de Kleer (1:00:55.980)

Wow.

Lex Fridman (1:00:56.980)

Yeah.

Katherine de Kleer (1:00:57.980)

No, you're right.

Lex Fridman (1:00:58.980)

That would be gorgeous.

Lex Fridman (1:01:00.060)

What else about Earth is interesting besides volcanoes?

Lex Fridman (1:01:03.820)

So plate tectonics.

Katherine de Kleer (1:01:04.820)

I didn't realize that that was a unique element of a planet in the solar system, because that,

Katherine de Kleer (1:01:13.540)

I wonder what, I mean, we experienced as human beings, it's quite painful because of earthquakes

Lex Fridman (1:01:17.940)

and all those kinds of things, but I wonder if there's nice features to it.

Lex Fridman (1:01:22.260)

Yeah.

Lex Fridman (1:01:23.260)

So coming back to habitability again, things like tectonics and plate tectonics are thought

Lex Fridman (1:01:30.020)

to play an important role in the surface being habitable.

Lex Fridman (1:01:33.220)

And that's because you have a way of recycling materials.

Lex Fridman (1:01:36.840)

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

Katherine de Kleer (1:01:41.940)

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

Lex Fridman (1:01:48.060)

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

Lex Fridman (1:01:53.880)

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

Katherine de Kleer (1:01:58.620)

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

Katherine de Kleer (1:02:04.100)

of refresh your nutrient supply, in a sense, or the sort of raw materials that the surface

Lex Fridman (1:02:10.060)

has to work with.

Lex Fridman (1:02:11.980)

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

Katherine de Kleer (1:02:19.580)

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

Katherine de Kleer (1:02:24.540)

atmosphere.

Lex Fridman (1:02:25.540)

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

Katherine de Kleer (1:02:30.820)

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

Lex Fridman (1:02:35.780)

water.

Lex Fridman (1:02:37.260)

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

Lex Fridman (1:02:41.780)

And also see like tiny dot satellites flying around and rockets.

Katherine de Kleer (1:02:45.180)

Well, sure, yes.

Katherine de Kleer (1:02:46.180)

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

Lex Fridman (1:02:50.300)

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

Lex Fridman (1:02:58.020)

I think it would take a while, right?

Katherine de Kleer (1:03:00.220)

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

Lex Fridman (1:03:06.020)

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

Lex Fridman (1:03:10.180)

There's like ants, they would probably detect ants, right?

Katherine de Kleer (1:03:15.060)

Or they probably would focus on the water and the fish because there's like a lot of

Katherine de Kleer (1:03:19.140)

water.

Katherine de Kleer (1:03:20.140)

I was surprised to learn that there's more species on land than there is in the sea.

Katherine de Kleer (1:03:25.060)

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

Lex Fridman (1:03:29.420)

Or on land?

Katherine de Kleer (1:03:30.420)

On land.

Lex Fridman (1:03:31.420)

Not in the sea?

Katherine de Kleer (1:03:32.420)

No.

Lex Fridman (1:03:33.420)

Not in the sea.

Katherine de Kleer (1:03:34.420)

Not in the sea, but no, the variety that like the branches created by evolution, apparently

Katherine de Kleer (1:03:40.220)

it's probably a good answer from evolutionary biology perspective, why land created so much

Katherine de Kleer (1:03:45.580)

diversity, but it did.

Lex Fridman (1:03:46.980)

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

Katherine de Kleer (1:03:53.660)

not, it's not diversity friendly.

Lex Fridman (1:03:57.580)

What can I say?

Katherine de Kleer (1:03:58.580)

It needs to improve its diversity.

Lex Fridman (1:04:01.580)

Do you think the aliens would come, I mean, the first thing they would see is I suppose

Katherine de Kleer (1:04:04.940)

our cities, assuming that they had some idea of what a natural world looked like, they

Lex Fridman (1:04:10.220)

would see cities and say, these don't belong.

Lex Fridman (1:04:13.580)

Which of these many species created these?

Lex Fridman (1:04:15.820)

Yeah.

Katherine de Kleer (1:04:16.820)

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

Katherine de Kleer (1:04:21.620)

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

Katherine de Kleer (1:04:27.620)

shapes.

Lex Fridman (1:04:28.620)

Like if it's, cause to me like hard corners, like what do we think is engineered?

Katherine de Kleer (1:04:38.180)

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

Katherine de Kleer (1:04:42.500)

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

Katherine de Kleer (1:04:47.460)

the basic natural physics of the world.

Lex Fridman (1:04:52.420)

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

Katherine de Kleer (1:04:58.220)

be the plate tectonics.

Lex Fridman (1:05:01.220)

It could be like, that they're like the volcanoes that'd be okay.

Katherine de Kleer (1:05:04.940)

That's a source of heat.

Lex Fridman (1:05:05.940)

And then they would focus.

Katherine de Kleer (1:05:07.220)

They might literally, I mean, depending on how alien life forms are, they might notice

Katherine de Kleer (1:05:12.180)

the microorganisms before they notice the big, like notice the ant before the elephant.

Katherine de Kleer (1:05:20.260)

Cause like there's a lot more of them depending what they're measuring.

Katherine de Kleer (1:05:24.100)

We think like size matters, but maybe with their tools of measurement, they would look

Katherine de Kleer (1:05:29.220)

for quantity versus size.

Lex Fridman (1:05:32.420)

Like why focus on the big thing, focus on the thing that there's a lot of.

Lex Fridman (1:05:36.980)

And when they see humans, depending on their measurement devices, they might see we're

Lex Fridman (1:05:40.640)

made up of billions of organisms.

Katherine de Kleer (1:05:43.760)

Like the fact that we have, we're very human.

Lex Fridman (1:05:46.300)

We think we're one organism, but that may not be the case.

Katherine de Kleer (1:05:49.940)

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

Katherine de Kleer (1:05:56.420)

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

Katherine de Kleer (1:06:03.900)

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

Lex Fridman (1:06:11.500)

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

Lex Fridman (1:06:16.380)

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

Lex Fridman (1:06:20.500)

So we talked a lot about volcanic patterns.

Katherine de Kleer (1:06:26.260)

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

Lex Fridman (1:06:32.980)

temperature, all those kinds of things?

Katherine de Kleer (1:06:36.620)

Yeah.

Lex Fridman (1:06:38.480)

So there's sort of every planet and moon has a kind of interesting and unique weather pattern.

Lex Fridman (1:06:45.180)

And those weather patterns are really, we don't have a good understanding of them.

Katherine de Kleer (1:06:50.820)

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

Katherine de Kleer (1:06:56.900)

these atmospheres, why the storm systems occur.

Lex Fridman (1:07:00.560)

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

Katherine de Kleer (1:07:08.740)

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

Katherine de Kleer (1:07:13.780)

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

Lex Fridman (1:07:18.340)

and how the circulation is working.

Lex Fridman (1:07:20.380)

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

Katherine de Kleer (1:07:26.660)

to some altitude that's a little bit colder and that species will condense out and form

Lex Fridman (1:07:30.640)

a cloud at that altitude.

Lex Fridman (1:07:32.620)

And we can detect in some cases what those clouds are composed of.

Lex Fridman (1:07:39.220)

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

Katherine de Kleer (1:07:46.340)

the atmospheric circulation is, say, coming up at the equator and going down at the poles

Lex Fridman (1:07:50.940)

or whether you have multiple cells in the atmosphere.

Lex Fridman (1:07:53.620)

And I mean, Jupiter's atmosphere is just insane.

Lex Fridman (1:07:57.940)

There's so much going on.

Katherine de Kleer (1:07:58.940)

You look at these pictures and there's all these vortices and antivortices and you have

Katherine de Kleer (1:08:02.900)

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

Katherine de Kleer (1:08:09.200)

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

Lex Fridman (1:08:20.460)

and circulation.

Lex Fridman (1:08:22.780)

What are these vortices?

Lex Fridman (1:08:24.860)

What's the basic material of the storms?

Katherine de Kleer (1:08:27.760)

It's condensed molecules from the atmosphere.

Lex Fridman (1:08:30.100)

So ammonia ice particles in the case of Jupiter, it's methane ice in the case of let's say

Katherine de Kleer (1:08:36.100)

Uranus and Neptune and other species, you can kind of construct a chemical model for

Lex Fridman (1:08:40.940)

which species can condense where.

Lex Fridman (1:08:42.780)

And so you see a cloud at a certain altitude within the atmosphere and you can make a guess

Katherine de Kleer (1:08:47.180)

at what that cloud is made of and sometimes measure it directly and different species

Katherine de Kleer (1:08:51.900)

make different colors as well.

Lex Fridman (1:08:53.900)

Oh, cool.

Katherine de Kleer (1:08:55.220)

Ice storms.

Lex Fridman (1:08:56.220)

Okay.

Katherine de Kleer (1:08:57.220)

I mean, the climate of Uranus has always been fascinating to me because it orbits on its

Lex Fridman (1:09:02.260)

side and it has a 42 year orbital period.

Lex Fridman (1:09:07.420)

And so, you know, with Earth, our seasons are because our equator is tipped just a little

Lex Fridman (1:09:11.620)

bit to the plane that we orbit in.

Lex Fridman (1:09:13.100)

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

Lex Fridman (1:09:16.240)

below the equator.

Lex Fridman (1:09:17.240)

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

Lex Fridman (1:09:22.940)

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

Lex Fridman (1:09:26.900)

And it's actually kind of amazing that the atmosphere doesn't look crazier than it does.

Lex Fridman (1:09:33.460)

But understanding how, taking again, like one of these extreme examples, if we can understand

Lex Fridman (1:09:38.500)

why that atmosphere behaves in the way it does, it's kind of a test of our understanding

Lex Fridman (1:09:43.580)

of how atmosphere is.

Lex Fridman (1:09:45.820)

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

Lex Fridman (1:09:55.540)

and that you're saying should probably lead to some chaos.

Lex Fridman (1:10:00.480)

And it doesn't.

Lex Fridman (1:10:01.480)

The fact that it doesn't tells you something about the atmosphere.

Lex Fridman (1:10:04.860)

So atmospheres have a property that surfaces don't have, which is that they can redistribute

Lex Fridman (1:10:08.440)

heat a lot more effectively.

Katherine de Kleer (1:10:09.900)

Right.

Lex Fridman (1:10:10.900)

So they have a stabilizing, like self regulating aspect to them that they're able to deal with

Katherine de Kleer (1:10:15.780)

extreme conditions.

Lex Fridman (1:10:19.700)

But predicting how that complex system unrolls is very difficult, as we know, about predicting

Katherine de Kleer (1:10:27.260)

the weather on Earth even.

Lex Fridman (1:10:28.260)

Oh, my goodness.

Katherine de Kleer (1:10:29.260)

Yeah.

Lex Fridman (1:10:30.260)

Even with the little variation we have on Earth.

Katherine de Kleer (1:10:31.260)

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

Lex Fridman (1:10:35.100)

You know, we've done this for Earth.

Katherine de Kleer (1:10:36.300)

People have tried to do these for other planets as well.

Lex Fridman (1:10:38.740)

And it is a really hard problem.

Lex Fridman (1:10:41.820)

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

Katherine de Kleer (1:10:45.820)

system, and people have tried to make these global circulation models and actually predict

Katherine de Kleer (1:10:50.540)

what's going to happen moving into sort of the next season of Titan.

Lex Fridman (1:10:55.060)

And those predictions have ended up being wrong.

Lex Fridman (1:10:57.060)

And so then, you know, I don't know, it's always exciting when a prediction is wrong

Katherine de Kleer (1:11:00.780)

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

Lex Fridman (1:11:06.020)

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

Lex Fridman (1:11:09.620)

it fit.

Katherine de Kleer (1:11:11.900)

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

Katherine de Kleer (1:11:15.980)

there will be like news programs reporting the weather with the fake confidence of like

Katherine de Kleer (1:11:22.500)

as if you can predict the weather.

Lex Fridman (1:11:25.700)

We talked quite a bit about planets and moons.

Lex Fridman (1:11:28.580)

Can we talk a little bit about asteroids?

Lex Fridman (1:11:31.780)

For sure.

Lex Fridman (1:11:32.780)

What is, what's an asteroid?

Lex Fridman (1:11:34.580)

And what kind of asteroids are there?

Lex Fridman (1:11:36.940)

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

Lex Fridman (1:11:41.860)

is the region, it's a region of debris basically between Mars and Jupiter.

Lex Fridman (1:11:49.580)

And the, these sort of belts of debris throughout the solar system, the outer solar system,

Katherine de Kleer (1:11:57.620)

you know, the Kuiper belt that we talked about, the asteroid belt, as well as certain other

Katherine de Kleer (1:12:01.780)

populations where they accumulate because they're gravitationally more favored, are

Lex Fridman (1:12:08.740)

remnant objects from the origin of the solar system.

Lex Fridman (1:12:11.620)

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

Katherine de Kleer (1:12:17.620)

they could come hit Earth, but scientifically it's, it gives us a window into understanding

Katherine de Kleer (1:12:27.820)

the composition of the material from which Earth and the other planets formed and how

Lex Fridman (1:12:34.620)

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

Lex Fridman (1:12:40.000)

So the asteroids, one could classify them in two different ways.

Lex Fridman (1:12:44.200)

Some of them are ancient objects.

Lex Fridman (1:12:45.980)

So they accreted out of the sort of disc of material that the whole solar system formed

Lex Fridman (1:12:54.540)

out of and have kind of remained ever since more or less the same.

Katherine de Kleer (1:13:02.500)

They've probably collided with each other and we see the, all these collisional fragments

Lex Fridman (1:13:06.300)

and you can actually look and based on their orbits say, you know, like these 50 objects

Katherine de Kleer (1:13:13.120)

originated as the same object.

Lex Fridman (1:13:16.300)

You can see them kind of dynamically moving apart after some big collision.

Lex Fridman (1:13:22.620)

And so some of them are these ancient objects maybe that have undergone collisions.

Lex Fridman (1:13:26.120)

And then there's this other category of object that is the one that I personally find really

Katherine de Kleer (1:13:30.500)

interesting which is remnants of objects that could have been planets.

Lex Fridman (1:13:38.560)

So early on a bunch of potential planets accreted that we call planetesimals and they formed

Lex Fridman (1:13:45.540)

and they formed with a lot of energy and they had enough time to actually differentiate.

Lex Fridman (1:13:49.180)

So some of these objects differentiated into cores and mantles and crests.

Lex Fridman (1:13:53.560)

And then they were subsequently disrupted in these massive collisions and they, now

Katherine de Kleer (1:14:00.720)

we have these fragments, we think fragments floating around the asteroid belt that are

Katherine de Kleer (1:14:05.140)

like bits of mantle, bits of core, bits of crest basically.

Lex Fridman (1:14:08.740)

So it's like puzzle pieces that you might be able to stitch together or I guess it's

Katherine de Kleer (1:14:14.820)

all mixed up so you can't stitch together the original planet candidates or is that

Katherine de Kleer (1:14:22.480)

possible to try to see if they kind of, I mean, there's too many objects in there to.

Katherine de Kleer (1:14:28.900)

I think that there are cases where people have kind of looked at objects and by looking

Katherine de Kleer (1:14:33.780)

at their orbits, they say these objects should have originated together, but they have very

Katherine de Kleer (1:14:37.620)

different compositions.

Lex Fridman (1:14:39.620)

And so then you can hypothesize maybe they were different fragments of a differentiated

Katherine de Kleer (1:14:44.340)

object.

Lex Fridman (1:14:45.340)

But one of the really cool things about this is, you know, we've been talking about getting

Katherine de Kleer (1:14:49.620)

clues into the interiors of planets.

Lex Fridman (1:14:52.620)

We've never seen a planetary core or deep mantle directly.

Katherine de Kleer (1:14:57.580)

Some mantle material comes up on our surface and then we can see it, but, you know, sort

Lex Fridman (1:15:01.780)

of in bulk.

Katherine de Kleer (1:15:03.800)

We haven't seen these things directly and these asteroids potentially give us a chance

Katherine de Kleer (1:15:08.220)

to like look at what our own core and mantle is like, or at least would be like if it had

Katherine de Kleer (1:15:14.060)

been also floating through space for a few billion years and getting irradiated and all

Lex Fridman (1:15:18.980)

that.

Lex Fridman (1:15:19.980)

But it's a cool potential window or like analogy into the interior of our own planet.

Lex Fridman (1:15:26.020)

Well, how do you begin studying some of these asteroids?

Lex Fridman (1:15:30.660)

What if you were to put together a study, like what are the interesting questions to

Lex Fridman (1:15:33.980)

ask that are a little bit more specific?

Lex Fridman (1:15:37.140)

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

Lex Fridman (1:15:43.860)

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

Lex Fridman (1:15:51.780)

So when it comes to the asteroids, there are so many of them and the big pictures or the

Katherine de Kleer (1:15:58.060)

big questions are answered, so some questions can be answered by zooming in in detail on

Katherine de Kleer (1:16:08.140)

individual object, but mostly you're trying to do a statistical study.

Lex Fridman (1:16:11.940)

So you want to look at thousands of objects, even hundreds of thousands of objects and

Katherine de Kleer (1:16:18.300)

figure out what their composition is and look at, you know, how many big asteroids there

Katherine de Kleer (1:16:25.620)

are of this composition versus how many small asteroids of this other composition and put

Katherine de Kleer (1:16:29.380)

together these kinds of statistical properties of the asteroid belt.

Lex Fridman (1:16:34.180)

And those properties can be directly compared with the results of simulations for the formation

Katherine de Kleer (1:16:40.160)

of the solar system.

Lex Fridman (1:16:42.300)

What do we know about the surfaces of asteroids or the contents of the insides of asteroids

Lex Fridman (1:16:50.620)

and what are still open questions?

Lex Fridman (1:16:52.960)

So I would say that we don't know a whole lot about their compositions.

Katherine de Kleer (1:17:00.340)

Most of them are small and so you can't study them in such detail with telescopes as you

Katherine de Kleer (1:17:07.220)

could, you know, a planet or moon and at the same time, because there are so many of them,

Katherine de Kleer (1:17:11.780)

you could send a spacecraft to a few, but you can't really like get a statistical survey

Lex Fridman (1:17:17.500)

with spacecraft.

Lex Fridman (1:17:18.500)

And so a lot of what we, a lot of what has been done comes down to sort of classification.

Katherine de Kleer (1:17:24.260)

You look at how bright they are, you look at whether they're red or blue, simply, you

Katherine de Kleer (1:17:31.060)

know, whether their spectrum is sloped towards long wavelengths or short wavelengths.

Katherine de Kleer (1:17:35.180)

There are certain, if you point a spectrograph at their surfaces, there are certain features

Katherine de Kleer (1:17:41.740)

you can see.

Lex Fridman (1:17:42.740)

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

Lex Fridman (1:17:46.900)

But these are the sort of, they're pretty basic questions.

Katherine de Kleer (1:17:50.100)

We're still trying to classify them based on fairly basic information in kind of combination

Katherine de Kleer (1:17:55.380)

with our general understanding of the material the solar system formed from.

Lex Fridman (1:17:59.520)

And so you're sort of, you're coming in with prior knowledge, which is that you more or

Katherine de Kleer (1:18:03.380)

less know what the materials are the solar system formed from, and then you're trying

Lex Fridman (1:18:06.540)

to classify them into these categories.

Katherine de Kleer (1:18:09.540)

There's still a huge amount of room for understanding them better and for understanding how their

Lex Fridman (1:18:17.140)

surfaces are changing in the space environment.

Lex Fridman (1:18:20.180)

Is it hard to land on an asteroid?

Lex Fridman (1:18:23.100)

Is this a dumb question?

Katherine de Kleer (1:18:26.100)

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

Lex Fridman (1:18:36.300)

dense field of debris.

Katherine de Kleer (1:18:38.180)

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

Lex Fridman (1:18:44.100)

It is mostly open space.

Lex Fridman (1:18:47.100)

So mentally do picture like mostly open space with some rocks.

Lex Fridman (1:18:51.540)

The problem is some of them are not thought to be solid.

Lex Fridman (1:18:54.660)

So some of these asteroids, especially these, these core mantle fragments, you can think

Katherine de Kleer (1:18:58.480)

of as sort of solid like a planet, but some of them are just kind of aggregates of material.

Katherine de Kleer (1:19:04.500)

We call them rubble piles.

Lex Fridman (1:19:06.680)

And so there's not necessarily.

Katherine de Kleer (1:19:08.660)

Might look like a rock, but do a lot of them have kind of clouds around them, like a dust

Lex Fridman (1:19:15.780)

cloud thing, or like, do you know what you're stepping on when you try to land on it?

Lex Fridman (1:19:22.900)

Like what are we supposed to be visualizing here?

Lex Fridman (1:19:26.180)

This is like very few have water, right?

Katherine de Kleer (1:19:29.100)

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

Lex Fridman (1:19:32.700)

comets in the sense of having clouds around them.

Katherine de Kleer (1:19:37.300)

There are some crazy asteroids that do become active like comets.

Lex Fridman (1:19:41.180)

That's the whole other category of thing that we don't understand.

Lex Fridman (1:19:45.820)

But their surfaces, I mean, we have visited some, you can find pictures that spacecraft

Lex Fridman (1:19:50.460)

have taken of them.

Katherine de Kleer (1:19:51.460)

We've actually scooped up material off of the surface of some of these objects.

Lex Fridman (1:19:54.700)

We're bringing it back to analyze it in the lab.

Lex Fridman (1:19:58.780)

And there's a mission that's launching next year to land on one of these supposedly core

Katherine de Kleer (1:20:04.380)

fragment objects to try to figure out what the heck it is and what's going on with it.

Lex Fridman (1:20:09.780)

But the surfaces, you know, they're, they're, you can picture a solid surface with some

Katherine de Kleer (1:20:16.420)

little grains of sand or pebbles on it and occasional boulders, maybe some fine dusty

Katherine de Kleer (1:20:23.340)

regions, dust kind of collecting in certain places.

Lex Fridman (1:20:28.020)

Is there this, do you worry about this?

Katherine de Kleer (1:20:30.580)

Is there any chance that one of these fellas destroys all of human civilization by an asteroid

Katherine de Kleer (1:20:41.320)

kind of colliding with something, changing its trajectory and then heading its way towards

Lex Fridman (1:20:45.780)

earth?

Lex Fridman (1:20:47.460)

That is definitely possible.

Lex Fridman (1:20:49.420)

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

Lex Fridman (1:20:54.260)

We're not tracking all of them.

Katherine de Kleer (1:20:56.020)

We can't track all of them yet.

Lex Fridman (1:20:57.860)

You know, there's still a lot of them.

Katherine de Kleer (1:21:01.820)

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

Lex Fridman (1:21:05.300)

them.

Lex Fridman (1:21:06.300)

But there are a lot of them out there and it would be potentially catastrophic if one

Lex Fridman (1:21:09.540)

of them impacted earth.

Lex Fridman (1:21:11.260)

Have you, are you aware of this Apophis object?

Lex Fridman (1:21:16.980)

So there's an asteroid, a near earth object called Apophis that people thought had a decent

Katherine de Kleer (1:21:23.140)

probability of hitting earth in 2029 and then potentially again in 2036.

Lex Fridman (1:21:28.840)

So they did a lot of studies.

Katherine de Kleer (1:21:29.940)

It's not actually going to hit earth, but it is going to come very close.

Katherine de Kleer (1:21:35.060)

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

Katherine de Kleer (1:21:40.780)

not visible from Los Angeles, but, and it's going to come a 10th of the way between the

Lex Fridman (1:21:50.580)

earth and the moon.

Katherine de Kleer (1:21:51.740)

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

Lex Fridman (1:21:55.940)

Oh wow.

Lex Fridman (1:21:56.940)

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

Lex Fridman (1:22:02.660)

not actually going to hit us, but it was.

Katherine de Kleer (1:22:04.300)

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

Lex Fridman (1:22:08.540)

to happen if an asteroid actually hits earth.

Katherine de Kleer (1:22:13.100)

That the scientific community and government will confidently say that, uh, we have nothing

Lex Fridman (1:22:23.300)

to worry about.

Katherine de Kleer (1:22:24.300)

It's going to be a close call.

Lex Fridman (1:22:26.340)

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

Katherine de Kleer (1:22:30.420)

They're not lying.

Katherine de Kleer (1:22:31.420)

It's just like the space of possibilities, because it's very difficult to track these

Katherine de Kleer (1:22:35.300)

kinds of things and there's a lot of kind of, um, there's complexities involved in this.

Katherine de Kleer (1:22:40.500)

There's a lot of uncertainties that I just, something tells me that human civilization

Katherine de Kleer (1:22:46.340)

will end with, we'll see it coming.

Lex Fridman (1:22:49.540)

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

Katherine de Kleer (1:22:54.020)

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

Lex Fridman (1:22:57.740)

No problem.

Lex Fridman (1:22:58.740)

And last minute it'll be like, oops, that was a miscalculation.

Lex Fridman (1:23:01.140)

And it's all over in a matter of like a week, or just very positive and optimistic today.

Katherine de Kleer (1:23:10.380)

Is there any chance that Bruce Willis can save us in the sense that from what you know

Katherine de Kleer (1:23:16.380)

about asteroids, is there something that, um, you can catch them early enough to, uh,

Katherine de Kleer (1:23:24.460)

change volcanic, uh, eruptions, right, um, sort of drill, put a nuclear weapon inside

Lex Fridman (1:23:31.660)

and break up the asteroid or change its trajectory?

Katherine de Kleer (1:23:37.180)

There is potential for that.

Katherine de Kleer (1:23:38.980)

If you catch it early enough in advance, um, I think in theory, if you knew five years

Katherine de Kleer (1:23:48.180)

in advance, um, depending on the objects and how close, how much you would need to deflect

Lex Fridman (1:23:56.380)

it, um, you could deflect it a little bit.

Katherine de Kleer (1:24:00.620)

I don't know that it would be sufficient in all cases.

Katherine de Kleer (1:24:04.100)

Um, and this is definitely not my specific area of expertise, but my understanding is

Katherine de Kleer (1:24:09.500)

that there is something you could do.

Katherine de Kleer (1:24:11.980)

Um, but it also, how you would carry that out depends a lot on the properties of the

Katherine de Kleer (1:24:17.460)

asteroid.

Lex Fridman (1:24:18.460)

If it's a solid object versus a rubble pile.

Lex Fridman (1:24:20.220)

So let's say you planted some bomb in the middle of it and it blew up, but it was just

Lex Fridman (1:24:26.980)

kind of a pile of material anyway.

Lex Fridman (1:24:28.940)

And then that material comes back together and then you kind of just have the same thing.

Katherine de Kleer (1:24:33.420)

Presumably its trajectory would be altered, but it's, it's like a terminator too.

Katherine de Kleer (1:24:38.620)

When it's like the thing that just like you shoot it in splashes and then comes back together

Lex Fridman (1:24:43.120)

will be very useless.

Katherine de Kleer (1:24:44.940)

That's fascinating.

Lex Fridman (1:24:45.940)

It was fascinating.

Katherine de Kleer (1:24:48.580)

I've gotten a lot of hope from watching, uh, uh, SpaceX rockets that land.

Lex Fridman (1:24:56.860)

There's so much.

Katherine de Kleer (1:24:57.940)

It's like, Oh wow.

Katherine de Kleer (1:24:58.940)

From an AI perspective, from a robotics perspective, wow, we can do a hell of an amazing job with

Katherine de Kleer (1:25:06.140)

control.

Lex Fridman (1:25:09.380)

And but then we have an understanding about surfaces here on earth, we can map up a lot

Katherine de Kleer (1:25:15.140)

of things.

Lex Fridman (1:25:16.140)

I wonder if we can do that.

Katherine de Kleer (1:25:17.140)

Some kind of detail of being able to have that same level of precision in landing on

Katherine de Kleer (1:25:23.740)

surfaces with as wide of a variety as asteroids have to be able to understand the exact properties

Katherine de Kleer (1:25:31.940)

of the surface and be able to encode that into whatever rocket that lands sufficiently

Katherine de Kleer (1:25:37.620)

to, I presume humans, unlike the, unlike the movies, humans would likely get in the way.

Katherine de Kleer (1:25:44.580)

Like it should all be done by robots and like land drill, place the, the explosive that

Lex Fridman (1:25:52.900)

should all be done through control, the robots.

Lex Fridman (1:25:56.580)

And then you should be able to dynamically adjust to, um, to the surface.

Katherine de Kleer (1:26:01.080)

The flip side of that for a robotics person, I don't know if you've seen these, it's been

Katherine de Kleer (1:26:05.620)

very heartbreaking.

Katherine de Kleer (1:26:07.100)

Uh, somebody I know well, Russ Tedrick at MIT led the DARPA robotics challenge team for

Katherine de Kleer (1:26:14.060)

the humanoid robot challenge for DARPA.

Katherine de Kleer (1:26:15.980)

I don't know if you've seen videos of robots on two feet falling, but you're talking about

Katherine de Kleer (1:26:20.460)

millions, you know, several years of work from with some of the most brilliant roboticists

Lex Fridman (1:26:24.740)

in the world, millions of dollars.

Lex Fridman (1:26:27.060)

And the final thing is a highlight video on YouTube of robots falling, but they had a

Lex Fridman (1:26:31.140)

lot of trouble with uneven surfaces.

Katherine de Kleer (1:26:33.800)

That's basically what you have to do with, uh, the challenge involves you're mostly autonomous

Katherine de Kleer (1:26:38.420)

with some partial human communication, but that human communication is broken up.

Katherine de Kleer (1:26:43.300)

Like you don't get a, you get a noisy channel, so you can, humans can, which is very similar

Lex Fridman (1:26:48.700)

to what it would be like in humans remotely operating a thing on an asteroid.

Lex Fridman (1:26:54.860)

And so with that, robots really struggled.

Katherine de Kleer (1:26:57.420)

There's some hilarious painful videos of like a robot, not able to like open the door.

Lex Fridman (1:27:03.300)

And then it tries to open the door without like, it misses the handle and in doing so

Lex Fridman (1:27:07.640)

like falls, I mean, it's, um, it's painful to watch.

Lex Fridman (1:27:12.020)

So like that, there's that, and then there's SpaceX.

Lex Fridman (1:27:15.740)

So I have hope from SpaceX and then I have less hope from bipedal robotics, um, but it's

Katherine de Kleer (1:27:21.780)

fun.

Lex Fridman (1:27:22.780)

It's fun to kind of imagine.

Lex Fridman (1:27:23.900)

And I think the planetary side of it comes into play in understanding the surfaces of

Katherine de Kleer (1:27:28.420)

these asteroids more and more that, you know, forget sort of destruction of human civilization.

Katherine de Kleer (1:27:34.540)

It'd be cool to have like spacecraft just landing on all these asteroids to study them

Katherine de Kleer (1:27:39.100)

at scale and being able to figure out dynamically what, you know, whether it's a rubble pile

Lex Fridman (1:27:44.940)

or whether it's, um, a solid objects, like, do you see that kind of future of science?

Katherine de Kleer (1:27:51.660)

Maybe a hundred, 200, 300 years from now, where there's just robots expanding out through

Katherine de Kleer (1:27:57.860)

the solar system, like sensors, essentially.

Katherine de Kleer (1:28:00.800)

Some of it taking pictures from a distance, some of them landing, just exploring and giving

Katherine de Kleer (1:28:04.260)

us data.

Lex Fridman (1:28:05.260)

Cause it feels like we're working with very little data right now.

Katherine de Kleer (1:28:10.580)

Sure I, I do see exploration going that way.

Katherine de Kleer (1:28:14.420)

I think, um, the way that NASA is currently or historically has been doing missions is

Katherine de Kleer (1:28:23.340)

putting together these, these really large missions that do a lot of things and are extremely

Lex Fridman (1:28:28.140)

well tested and have a very low rate of failure.

Lex Fridman (1:28:30.500)

But now that, um, these sort of CubeSat technologies are, are becoming easier to build, easier

Lex Fridman (1:28:38.840)

to launch, they're, they're very cheap.

Lex Fridman (1:28:41.700)

And you know, NASA is getting involved in this as well.

Katherine de Kleer (1:28:43.980)

There's, there's a lot of interest in these missions that are relatively small, relatively

Katherine de Kleer (1:28:48.960)

cheap and just do one thing.

Lex Fridman (1:28:50.580)

So you can really optimize it to just do this one thing.

Lex Fridman (1:28:54.160)

And maybe you could build a hundred of them and send them to different asteroids.

Lex Fridman (1:28:57.140)

And they would just collect this one piece of information from each asteroid.

Katherine de Kleer (1:29:01.100)

It's a kind of different, more distributed way of doing science, I guess.

Lex Fridman (1:29:06.700)

And there's a ton of potential there, I agree.

Katherine de Kleer (1:29:11.160)

Let me ask you about objects or one particular object from outside our solar system.

Lex Fridman (1:29:17.220)

We don't get to study many of these, right?

Katherine de Kleer (1:29:19.660)

They don't, we don't get stuff that just flies in out of nowhere from outside the solar system

Lex Fridman (1:29:24.580)

and flies through.

Katherine de Kleer (1:29:25.580)

Apparently there's been two recently in the past few years.

Lex Fridman (1:29:30.460)

One of them is Amuamua.

Lex Fridman (1:29:34.540)

What are your thoughts about Amuamua?

Lex Fridman (1:29:37.340)

So fun to say.

Katherine de Kleer (1:29:38.340)

Could it, could it be space junk from a distant alien civilization or is it just a weird shaped

Lex Fridman (1:29:44.260)

comet?

Katherine de Kleer (1:29:45.260)

I like the way that's phrased.

Lex Fridman (1:29:49.540)

Um, so Amuamua is, is a fascinating object.

Katherine de Kleer (1:29:53.540)

Just the fact that we have started discovering things that are coming in from outside our

Lex Fridman (1:29:57.380)

solar system is amazing and can, can start to study them.

Lex Fridman (1:30:01.980)

And now that we have seen some, we can design now kind of thinking in advance.

Lex Fridman (1:30:09.340)

The next time we see one, we will be much more ready for it.

Katherine de Kleer (1:30:11.980)

We will know which telescopes we want to point at it.

Katherine de Kleer (1:30:14.140)

We will have explored whether we could even launch a fast turnaround mission to actually

Katherine de Kleer (1:30:18.660)

like get to it before it leaves the solar system.

Katherine de Kleer (1:30:23.540)

In terms of Amuamua, yeah, it's, for an object in our solar system, it's really unusual in

Katherine de Kleer (1:30:30.460)

two particular ways.

Katherine de Kleer (1:30:33.820)

One is the dimensions that we don't see natural things in our solar system that are kind of

Katherine de Kleer (1:30:38.860)

long and skinny.

Katherine de Kleer (1:30:39.980)

We see, the things we see in our solar system don't deviate from spherical by that much.

Lex Fridman (1:30:45.820)

And then that it showed these strange properties of accelerating as it was leaving the solar

Lex Fridman (1:30:50.540)

system, which was not understood at first.

Lex Fridman (1:30:53.380)

So in terms of the alien space junk, you know, as a scientist, I cannot rule out that possibility.

Lex Fridman (1:31:03.180)

I have no evidence to the contrary.

Katherine de Kleer (1:31:05.540)

Um, however,

Lex Fridman (1:31:06.540)

See, you're saying there's a chance.

Katherine de Kleer (1:31:10.460)

I cannot, I cannot, as a scientist, honestly say that I can rule out that it's alien space

Lex Fridman (1:31:16.580)

junk.

Katherine de Kleer (1:31:17.580)

However, I see the kind of alien explanation as following this, the Sagan's extraordinary

Lex Fridman (1:31:26.640)

claims require extraordinary evidence.

Katherine de Kleer (1:31:29.200)

If you are going to actually claim that something is aliens, you need to carefully evaluate,

Katherine de Kleer (1:31:37.580)

everyone needs to carefully evaluate the other options and see whether it could just be something

Katherine de Kleer (1:31:43.260)

that we know exists that makes sense.

Katherine de Kleer (1:31:45.260)

In the case of Oumuamua, there are explanations that fit well within our understanding of

Lex Fridman (1:31:53.660)

how things work.

Lex Fridman (1:31:54.660)

So there are a couple, there are two hypotheses for what it could be made of.

Katherine de Kleer (1:31:59.340)

They're both basically just ice shards.

Katherine de Kleer (1:32:02.140)

In one case, it's a nitrogen ice shard that came off of something like Pluto in another

Katherine de Kleer (1:32:05.940)

solar system, that Pluto got hit with something and broke up into pieces, and one of those

Lex Fridman (1:32:10.980)

pieces came through our solar system.

Katherine de Kleer (1:32:13.320)

In the other scenario, it's a bit of a failed solar system.

Lex Fridman (1:32:19.540)

So our solar system formed out of a collapsing molecular cloud.

Katherine de Kleer (1:32:24.820)

Sometimes those molecular clouds are not massive enough, and they sort of collapse into bits,

Lex Fridman (1:32:29.660)

but they don't actually form a solar system, but you end up with these kind of chunks of

Katherine de Kleer (1:32:33.180)

hydrogen ice, apparently.

Lex Fridman (1:32:35.100)

And so one of those chunks of hydrogen ice could have got ejected and passed through

Katherine de Kleer (1:32:38.860)

our solar system.

Lex Fridman (1:32:39.860)

So both cases explain these properties in about the same way.

Lex Fridman (1:32:45.780)

So those ices will sublimate once they've passed the sun, and so as they're moving away

Katherine de Kleer (1:32:50.720)

from the sun, you have the hydrogen or nitrogen ice sublimating off the sunward part of it,

Lex Fridman (1:32:55.860)

and so that is responsible for the acceleration.

Katherine de Kleer (1:32:58.940)

The shape also, because you have all this ice sublimating off the surface, if you take

Katherine de Kleer (1:33:04.760)

something, the analogy that works pretty well here is for a bar of soap.

Katherine de Kleer (1:33:11.220)

Your bar of soap starts out sort of close to spherical, at least from a physicist perspective,

Lex Fridman (1:33:17.140)

and as you use it over time, you eventually end up with this long, thin shard because

Lex Fridman (1:33:21.380)

it's been just by sort of weathering, as we would call it.

Lex Fridman (1:33:28.100)

And so in the same way, if you just sublimate material off of one of these ice shards, it

Lex Fridman (1:33:32.320)

ends up long and thin, and it ends up accelerating out of the solar system.

Lex Fridman (1:33:37.020)

And so given that these properties can be reasonably well explained that way, we should

Lex Fridman (1:33:43.380)

be extremely skeptical about attributing things to aliens.

Katherine de Kleer (1:33:47.380)

See, the reason I like to think that it's aliens is because it puts a lot of priority

Lex Fridman (1:33:54.060)

on us not being lazy and we need to catch this thing next time it comes around.

Katherine de Kleer (1:34:00.020)

I like the idea that there's objects, it almost saddens me, they come out of the darkness

Lex Fridman (1:34:06.420)

really fast and just fly by and go and leave.

Katherine de Kleer (1:34:10.620)

It just seems like a wasted opportunity not to study them.

Katherine de Kleer (1:34:16.260)

It's the easiest way to do space travel outside of the solar system is having the things come

Katherine de Kleer (1:34:22.540)

to us.

Lex Fridman (1:34:23.540)

Right?

Katherine de Kleer (1:34:24.540)

I like that way of putting it.

Lex Fridman (1:34:25.540)

And it would be nice to just land on it.

Lex Fridman (1:34:28.880)

And first of all, really importantly, detect it early and then land on it with a really

Lex Fridman (1:34:36.620)

nice spacecraft and study the hell out of it.

Katherine de Kleer (1:34:47.500)

If there's a chance it's aliens, alien life, it just feels like such a cheap way, inexpensive

Katherine de Kleer (1:34:56.740)

way to get information about alien life or something interesting that's out there.

Lex Fridman (1:35:03.180)

And I'm not sure if an ice shard from another planetary system will be interesting, but

Lex Fridman (1:35:08.300)

it very well could be.

Katherine de Kleer (1:35:09.300)

It could be totally new sets of materials.

Lex Fridman (1:35:11.440)

It could be, tell us about composition of planets we don't quite understand.

Lex Fridman (1:35:16.660)

And it's just nice when, especially in the case of a Moa Moa, I guess it was pretty

Lex Fridman (1:35:19.620)

close to earth.

Katherine de Kleer (1:35:20.620)

It would have been nice to, don't go there, they come to us, I don't know.

Lex Fridman (1:35:30.260)

That's what makes me quite sad.

Katherine de Kleer (1:35:31.420)

It's a missed opportunity.

Lex Fridman (1:35:32.420)

Well, yeah.

Lex Fridman (1:35:34.060)

And whether you think it's aliens or not, it's a missed opportunity, but we weren't

Lex Fridman (1:35:39.100)

prepared and we will be prepared for the next ones.

Lex Fridman (1:35:44.380)

So there's been a movement in astronomy more towards what's called time domain astronomy.

Lex Fridman (1:35:49.140)

So kind of monitoring the whole sky all the time at all wavelengths.

Katherine de Kleer (1:35:53.060)

That's kind of the goal.

Lex Fridman (1:35:54.060)

And so we expect to detect many more of these in the future, even though these were the

Katherine de Kleer (1:35:58.020)

first two we saw, our potential to detect them is only increasing with time.

Lex Fridman (1:36:02.020)

And so there will be more opportunities and based on these two, we now can actually sit

Lex Fridman (1:36:09.260)

and think about what we'll do when the next one shows up.

Katherine de Kleer (1:36:11.860)

I also, what it made me realize, I know I didn't really think through this, but it made

Katherine de Kleer (1:36:16.740)

me realize if there is alien civilizations out there, the thing we're most likely to

Lex Fridman (1:36:21.820)

see first would be space junk.

Katherine de Kleer (1:36:24.660)

My stupid understanding of it.

Lex Fridman (1:36:28.300)

And the second would be really dumb kind of, you could think of maybe like relay nodes

Katherine de Kleer (1:36:34.400)

or something objects that you need to have a whole lot of for particular purposes of

Lex Fridman (1:36:41.980)

like space travel and so on.

Katherine de Kleer (1:36:44.300)

Like a speed limit signs or something, I don't know, whatever we have on earth, a lot of

Lex Fridman (1:36:49.180)

that's dumb.

Katherine de Kleer (1:36:50.180)

It's not alien aliens in themselves.

Katherine de Kleer (1:36:52.660)

It's like artifacts that are useful to the engineering in the systems that are engineered

Katherine de Kleer (1:36:57.500)

by alien civilizations.

Lex Fridman (1:36:59.300)

So like it would, we would see a lot of stuff in terms of setting, in terms of looking for

Katherine de Kleer (1:37:05.600)

alien life and trying to communicate with it.

Katherine de Kleer (1:37:08.140)

Maybe we should be looking not for like smart creatures or systems to communicate with.

Katherine de Kleer (1:37:17.540)

Maybe we should be looking for artifacts or even as dumb as like space junk.

Lex Fridman (1:37:23.540)

It just kind of reframed my perspective of like, what are we looking for as signs?

Katherine de Kleer (1:37:29.340)

Cause there could be a lot of stuff that doesn't have intelligence, but gives us really strong

Lex Fridman (1:37:34.060)

signs that there's somewhere is life or intelligent life.

Lex Fridman (1:37:37.820)

And yeah, that made me kind of, I know it might be dumb to say, but reframe the kind

Lex Fridman (1:37:44.460)

of thing that we should be looking for.

Katherine de Kleer (1:37:46.940)

Yeah.

Lex Fridman (1:37:48.640)

So the benefit of looking for intelligent life is that we perhaps have a better chance

Katherine de Kleer (1:37:53.100)

of recognizing it.

Lex Fridman (1:37:56.260)

We couldn't necessarily recognize what an alien stop sign look like.

Lex Fridman (1:38:01.500)

And maybe the theorists are the people who sort of model and try to understand slow system

Lex Fridman (1:38:07.080)

objects are pretty good at coming up with models for anything.

Katherine de Kleer (1:38:10.220)

I mean, maybe a mua mua was a stop sign, but we're clever enough that we could come up

Lex Fridman (1:38:15.500)

with some physical explanations for it.

Lex Fridman (1:38:18.220)

And then we all want to go with the simplest possible, we all want to believe the sort

Lex Fridman (1:38:22.580)

of most skeptical possible explanation.

Lex Fridman (1:38:25.580)

And so we missed it because we're too good at coming up with alternate explanations for

Lex Fridman (1:38:29.460)

things.

Lex Fridman (1:38:30.460)

And it's such an outlier, such a rare phenomenon that we can't study a hundred or a thousand

Lex Fridman (1:38:35.820)

of these objects.

Katherine de Kleer (1:38:36.820)

We have to, we had just one.

Lex Fridman (1:38:38.140)

And so the science almost destroys the possibility of something special being there.

Katherine de Kleer (1:38:43.620)

It's like Johnny Ive, this designer of Apple, I don't know if you know who that is.

Lex Fridman (1:38:48.500)

He's the lead designer.

Katherine de Kleer (1:38:49.500)

He's the person who designed the iPhone and all the major things.

Lex Fridman (1:38:53.260)

And he talked about, he's brilliant, one of my favorite humans on earth and one of the

Katherine de Kleer (1:38:58.260)

best designers in the history of earth.

Katherine de Kleer (1:39:02.140)

He talked about like when he had this origins of an idea, like in his baby stages, he would

Katherine de Kleer (1:39:07.380)

not tell Steve Jobs because Steve would usually like trample all over it.

Lex Fridman (1:39:11.900)

He would say, this is a dumb idea.

Lex Fridman (1:39:14.060)

And so I sometimes think of the scientific community in that sense, because the weapon

Katherine de Kleer (1:39:19.860)

of the scientific method is so strong at its best that it sometimes crushes the out of

Katherine de Kleer (1:39:26.540)

the box outlier evidence.

Katherine de Kleer (1:39:30.580)

We don't get a lot of that evidence because we don't have, we're not lucky enough to have

Katherine de Kleer (1:39:35.020)

a lot of evidence.

Lex Fridman (1:39:36.020)

So we have to deal with just special cases and special cases could present an inkling

Katherine de Kleer (1:39:42.780)

of something much bigger, but the scientific method user tramples all over it.

Lex Fridman (1:39:46.900)

And it's hard to know what to do with that because the scientific method works, but at

Katherine de Kleer (1:39:52.260)

the same time, every once in a while, it's like a balance.

Katherine de Kleer (1:39:54.780)

You have to do 99% of the time, you have to do like scientific rigor, but every once in

Katherine de Kleer (1:40:00.380)

a while, this is not you saying, me saying, smoke some weed and sit back and think, I

Lex Fridman (1:40:06.300)

wonder, you know, it's the Joe Rogan thing.

Katherine de Kleer (1:40:09.300)

It's entirely possible that it's alien space junk.

Lex Fridman (1:40:13.980)

Anyway.

Katherine de Kleer (1:40:14.980)

Yeah.

Lex Fridman (1:40:15.980)

I think so.

Katherine de Kleer (1:40:16.980)

I completely agree.

Lex Fridman (1:40:18.380)

And I think that most scientists do speculate about these things.

Lex Fridman (1:40:23.580)

It's just at what point do you act on those things?

Lex Fridman (1:40:28.540)

So you're right that the scientific method has inherent skepticism, and for the most

Katherine de Kleer (1:40:33.060)

part, that's a good thing because it means that we're not just believing crazy things

Lex Fridman (1:40:39.220)

all the time.

Lex Fridman (1:40:41.540)

But it's an interesting point that requiring that high level of rigor occasionally means

Katherine de Kleer (1:40:50.040)

that you will miss something that is truly interesting because you needed to verify it

Katherine de Kleer (1:40:56.540)

three times and it wasn't verifiable.

Katherine de Kleer (1:40:58.620)

I also think like when you communicate with the general public, I think there's power

Katherine de Kleer (1:41:03.340)

in that 1% speculation of just demonstrating authenticity as a human being, as a curious

Lex Fridman (1:41:10.500)

human being.

Katherine de Kleer (1:41:12.540)

I think too often, I think this is changing, but I saw, I've been quite disappointed in

Lex Fridman (1:41:18.940)

my colleagues throughout 2020 with the coronavirus.

Katherine de Kleer (1:41:23.160)

There's too much speaking from authority as opposed to speaking from curiosity.

Katherine de Kleer (1:41:28.980)

There's some of the most incredible science has been done in 2020, especially on the virology

Katherine de Kleer (1:41:32.860)

biology side.

Lex Fridman (1:41:34.940)

And the kind of being talked down to by scientists is always really disappointing to me as opposed

Katherine de Kleer (1:41:41.860)

to inspiring.

Katherine de Kleer (1:41:42.860)

Like the things we, there's a lot of uncertainty about the coronavirus, but we know a lot of

Katherine de Kleer (1:41:47.820)

this stuff and we speak from scientists from various disciplines, speak from data in the

Lex Fridman (1:41:54.060)

face of that uncertainty.

Lex Fridman (1:41:56.500)

And we're curious, we don't know what the hell is going on.

Lex Fridman (1:41:58.740)

We don't know if this virus is going to evolve, mutate.

Katherine de Kleer (1:42:02.680)

We don't know if this virus or the next one might destroy all human civilization.

Lex Fridman (1:42:07.900)

You can't speak with certainty.

Katherine de Kleer (1:42:08.980)

In fact, I was on a survey paper about masks, something I don't talk much about because

Katherine de Kleer (1:42:16.620)

I don't like politics, but we don't know if masks work, but there's a lot of evidence

Katherine de Kleer (1:42:22.020)

to show that they work for this particular virus.

Lex Fridman (1:42:24.140)

The transmission of the virus is fascinating actually.

Katherine de Kleer (1:42:27.780)

The biomechanics of the way viruses spread is fascinating.

Lex Fridman (1:42:33.480)

If it wasn't destructive, it would be beautiful.

Lex Fridman (1:42:36.340)

And we don't know, but it's inspiring to apply the scientific method to the best of our ability,

Lex Fridman (1:42:42.180)

but also to show that you don't always know everything and to, perhaps not about the virus

Katherine de Kleer (1:42:47.300)

as much, but other things speculate.

Lex Fridman (1:42:51.020)

What if, you know, what if it's the worst case and the best case?

Katherine de Kleer (1:42:57.540)

Because that's ultimately what we are, descendants of apes that are just curious about the world

Lex Fridman (1:43:00.760)

around us.

Katherine de Kleer (1:43:01.760)

Yeah, I'll just add to that, not on the topic of masks, but on the topic of curiosity.

Katherine de Kleer (1:43:11.980)

I mean, I think that's, astronomy and planetary sciences, a field are a little, are unique

Katherine de Kleer (1:43:19.300)

because for better and for worse, they don't directly impact humanity.

Lex Fridman (1:43:26.420)

So you know, we're not studying virology to prevent transmission of, you know, illness

Katherine de Kleer (1:43:34.300)

amongst humans.

Lex Fridman (1:43:35.380)

We're not characterizing volcanoes on earth that could destroy cities.

Katherine de Kleer (1:43:40.180)

We, it really is a more curious and in my opinion, playful scientific field than many.

Lex Fridman (1:43:49.780)

So for better and worse, we can kind of afford to pursue some of the speculation more because

Katherine de Kleer (1:43:54.860)

human lives are not in danger if we speculate a little bit too freely and get something

Lex Fridman (1:44:00.420)

wrong.

Katherine de Kleer (1:44:01.420)

Yeah, definitely.

Katherine de Kleer (1:44:03.520)

In the space of AI, I am worried that we're sometimes too eager, speaking for myself,

Katherine de Kleer (1:44:09.940)

to like flip the switch to on just to see like what happens.

Katherine de Kleer (1:44:14.900)

Maybe sometimes we want to be a little bit careful about that because bad things might

Katherine de Kleer (1:44:19.260)

happen.

Katherine de Kleer (1:44:21.180)

Is there books or movies in your life long ago or recently that were inspiring, had an

Lex Fridman (1:44:27.940)

impact on you that you would recommend?

Lex Fridman (1:44:30.300)

Yeah, absolutely.

Lex Fridman (1:44:31.860)

So many that I just don't know where to start with it.

Lex Fridman (1:44:35.580)

So I love reading.

Katherine de Kleer (1:44:37.140)

I read obsessively.

Katherine de Kleer (1:44:38.340)

I've been reading fiction and a little bit of nonfiction, but mostly fiction obsessively

Katherine de Kleer (1:44:43.080)

since I was a child and just never stopped.

Lex Fridman (1:44:47.820)

So I have some favorite books.

Katherine de Kleer (1:44:50.140)

None of them are easy readings.

Lex Fridman (1:44:51.780)

So I definitely, I mean, I recommend them for somebody who likes an intellectual challenge

Katherine de Kleer (1:44:56.580)

in the books that they read.

Lex Fridman (1:44:59.980)

So maybe I should go chronologically.

Katherine de Kleer (1:45:02.900)

I have at least three.

Lex Fridman (1:45:04.580)

I'm not going to go through 50 here.

Katherine de Kleer (1:45:07.340)

Yeah, I'd love to also like maybe ideas that you took away from what you mentioned.

Lex Fridman (1:45:14.980)

Yeah.

Katherine de Kleer (1:45:15.980)

Yeah.

Lex Fridman (1:45:16.980)

Why they were so compelling to me.

Katherine de Kleer (1:45:20.300)

One of the first books that really captured my fascination was Nabokov's book Pale Fire.

Lex Fridman (1:45:27.580)

Are you familiar with it?

Lex Fridman (1:45:29.380)

So I read it actually for a class.

Katherine de Kleer (1:45:34.560)

It's one of the few books I've ever read for a class that I actually really liked.

Lex Fridman (1:45:39.820)

And the book is, it's in some sense a puzzle.

Katherine de Kleer (1:45:44.680)

He's a brilliant writer, of course, but the book is like, it's formatted like a poem.

Lex Fridman (1:45:52.320)

So there's an introduction, a very long poem and footnotes, and you get partway through

Katherine de Kleer (1:45:59.460)

it before realizing that the whole thing is actually a novel, unless you sort of read

Katherine de Kleer (1:46:04.020)

up on it going in.

Lex Fridman (1:46:05.020)

But the whole thing is a novel and there's a story that slowly reveals itself over the

Katherine de Kleer (1:46:10.820)

course of all of this and kind of reveals this just fascinating character basically

Lex Fridman (1:46:21.320)

and how his mind works in this story.

Katherine de Kleer (1:46:24.100)

The idea of a novel also being a kind of intellectual puzzle and something that slowly reveals itself

Katherine de Kleer (1:46:31.020)

over the course of reading was really fascinating to me and I have since found a lot more writers

Katherine de Kleer (1:46:36.460)

like that.

Katherine de Kleer (1:46:38.140)

In a contemporary example that comes to mind is Kazuo Ishiguro, who's pretty much all of

Katherine de Kleer (1:46:44.760)

his books are like slow reveals over the course of the book and like nothing much happens

Katherine de Kleer (1:46:49.600)

in the books, but you keep reading them because you just want to know like what the reality

Katherine de Kleer (1:46:54.280)

is that he's slowly revealing to you.

Lex Fridman (1:46:57.660)

The kind of discovery oriented reading maybe.

Lex Fridman (1:47:02.220)

What's the second one?

Lex Fridman (1:47:04.140)

Perhaps my favorite writer is Renier Maria Rilke.

Katherine de Kleer (1:47:08.100)

Wow.

Lex Fridman (1:47:09.100)

Are you familiar with him?

Katherine de Kleer (1:47:11.100)

No, also not familiar.

Lex Fridman (1:47:13.140)

You're hitting hidden ones.

Katherine de Kleer (1:47:14.140)

I mean, I know in the book of Well, but I've never read Pale Fire, but Rilke, I've never,

Lex Fridman (1:47:19.420)

I know it's a very difficult read, I know that much.

Katherine de Kleer (1:47:22.900)

Yeah, right.

Lex Fridman (1:47:23.900)

All of these are difficult reads.

Katherine de Kleer (1:47:25.220)

I think I just, I read for in part for an intellectual challenge, but Rilke, so he wrote

Katherine de Kleer (1:47:33.740)

one thing that might be characterizable as a novel, but he wrote a lot of poetry.

Katherine de Kleer (1:47:38.060)

I mean, he wrote this series of poems called the Duino Elegies that were very impactful

Katherine de Kleer (1:47:43.760)

for me personally, just emotionally, which actually it kind of ties in with astronomy

Katherine de Kleer (1:47:53.260)

in that there's a sense in which we're all going through our lives alone and there's

Katherine de Kleer (1:48:01.660)

just this sense of profound loneliness in the existence of every individual human.

Katherine de Kleer (1:48:10.100)

I think I was drawn to astronomy in part because the sort of vast spaces, the kind of loneliness

Lex Fridman (1:48:18.540)

and desolateness of space made the sort of internal loneliness feel okay.

Katherine de Kleer (1:48:24.660)

In a sense, it like gave companionship and that's how I feel about Rilke's poetry.

Katherine de Kleer (1:48:32.220)

He turns the kind of desolation and loneliness of human existence into something joyful and

Katherine de Kleer (1:48:40.920)

almost meaningful.

Katherine de Kleer (1:48:42.580)

Yeah, there's something about melancholy, I don't know about Rilke in general, but like

Katherine de Kleer (1:48:48.860)

contemplating the melancholy nature of the human condition that makes it okay.

Katherine de Kleer (1:49:00.860)

I got gentle from an engineering perspective, think that there is so much loneliness we

Katherine de Kleer (1:49:05.940)

haven't explored within ourselves yet and that's my hope is to build AI systems that

Lex Fridman (1:49:12.100)

help us explore our own loneliness.

Katherine de Kleer (1:49:15.580)

I think that's kind of what love is and friendship is, is somebody who in a very small way helps

Katherine de Kleer (1:49:22.020)

us explore our own loneliness, like they listen, we connect like two lonely creatures connect

Katherine de Kleer (1:49:28.860)

for a time and it's like, oh, like acknowledge that we exist together for a brief time, but

Katherine de Kleer (1:49:38.100)

in a somewhat shallow way, I think relative to how much it's possible to truly connect

Katherine de Kleer (1:49:43.260)

as two consciousnesses.

Lex Fridman (1:49:44.540)

So AI might be able to help on that front.

Lex Fridman (1:49:48.980)

So what's the third one?

Katherine de Kleer (1:49:49.980)

Actually, you know, I hadn't realized until this moment, but it's yet another one of these

Katherine de Kleer (1:49:54.100)

kind of slow reveal books.

Katherine de Kleer (1:49:57.160)

It's a contemporary Russian, I think Russian American writer named Olga Grushin and she

Katherine de Kleer (1:50:05.620)

wrote this just phenomenal book called The Dream Life of Sukhanov that I read this year.

Katherine de Kleer (1:50:12.660)

Maybe it was last year for the first time and it's just a really beautiful, this one

Katherine de Kleer (1:50:18.380)

you could call a character study, I think of a Russian father coming to terms with himself

Lex Fridman (1:50:26.060)

and his own past as he potentially slowly loses his mind.

Katherine de Kleer (1:50:33.660)

Slow reveal.

Lex Fridman (1:50:36.620)

Slow reveal.

Katherine de Kleer (1:50:37.620)

Well, that's apparent from the beginning.

Lex Fridman (1:50:39.740)

I hope I don't think it's a spoiler.

Katherine de Kleer (1:50:43.740)

Decline into madness.

Lex Fridman (1:50:44.740)

Spoiler alert.

Lex Fridman (1:50:45.740)

So all of these are really heavy.

Lex Fridman (1:50:47.540)

I don't know.

Katherine de Kleer (1:50:48.540)

I just, I don't have anything lighter to recommend.

Lex Fridman (1:50:50.540)

Ishiguro is the light version of this.

Katherine de Kleer (1:50:53.620)

Okay.

Lex Fridman (1:50:54.620)

Well, heavy has a certain kind of beauty to it in itself.

Katherine de Kleer (1:50:58.500)

Is there advice you would give to a young person today that looks up to the stars and

Lex Fridman (1:51:03.100)

wonders what the heck they want to do with their life?

Lex Fridman (1:51:05.160)

So career, science, life in general, you've for now chosen a certain kind of path of curiosity.

Lex Fridman (1:51:15.180)

What insights do you draw from that that you can give us advice to others?

Katherine de Kleer (1:51:20.340)

I think for somebody, I would not presume to speak to giving people advice on life and

Lex Fridman (1:51:27.940)

humanity overall, but for somebody thinking of being a scientist.

Lex Fridman (1:51:33.820)

So there are a couple of things, one sort of practical thing, which is career wise,

Katherine de Kleer (1:51:40.060)

I hadn't appreciated this going into science, but you need to, so the questions you're working

Katherine de Kleer (1:51:47.780)

on and the techniques you use are both of very high importance, maybe equal importance

Lex Fridman (1:51:55.260)

for being happy in your career.

Katherine de Kleer (1:51:58.060)

If there are questions you're interested in, but the techniques that you need to use to

Katherine de Kleer (1:52:01.660)

do them are tedious for you, then your job is going to be miserable even if the questions

Katherine de Kleer (1:52:07.700)

are inspiring.

Lex Fridman (1:52:09.100)

So you have to find, but if the techniques that you use are things that excite you, then

Katherine de Kleer (1:52:14.980)

your job is fun every day.

Lex Fridman (1:52:16.700)

So for me, I'm fascinated by the solar system and I love telescopes and I love doing data

Katherine de Kleer (1:52:22.100)

analysis, playing with data from telescopes, coming up with new ways to use telescopes

Lex Fridman (1:52:25.620)

and so that's where I have found that mesh.

Lex Fridman (1:52:28.100)

But if I was interested in, you know, the dynamical evolution of the solar system, how

Katherine de Kleer (1:52:32.740)

the orbits of things evolve, then I would need to do a different type of work that I

Katherine de Kleer (1:52:36.900)

would just not find as appealing and so it just wouldn't be a good fit.

Lex Fridman (1:52:39.800)

And so it sort of seems like an unromantic thing to have to think about the techniques

Katherine de Kleer (1:52:44.980)

being the thing you want to work on also, but it really makes a profound difference

Lex Fridman (1:52:49.100)

for I think your happiness and your scientific career.

Katherine de Kleer (1:52:52.300)

I think that's really profound.

Lex Fridman (1:52:53.300)

It's like the thing, the menial tasks.

Katherine de Kleer (1:52:56.300)

If you enjoy those, that's a really good sign that that's the right path for you.

Lex Fridman (1:53:00.300)

I think David Foster Wallace said that the key to life is to be unborable.

Lex Fridman (1:53:06.420)

So basically everything should be exciting.

Katherine de Kleer (1:53:09.700)

I don't think that's feasible, but you should find an area where everything is exciting.

Katherine de Kleer (1:53:15.220)

I mean, depending on the day, but you could find the joy in everything, not just the big

Katherine de Kleer (1:53:20.180)

exciting things that everyone thinks is exciting, but the details, the repetitive stuff, the

Katherine de Kleer (1:53:28.860)

menial stuff, the stuff that takes years, the stuff that involves a lot of failure and

Lex Fridman (1:53:32.980)

all those kinds of things that you find that enjoyable.

Katherine de Kleer (1:53:35.460)

That's actually really profound to focus on that because people talk about like dreams

Lex Fridman (1:53:40.800)

and passion and goals and so on, the big thing, but that's not actually what takes you there.

Lex Fridman (1:53:44.500)

What takes you there is every single day, putting in the hours, and that's what actually

Lex Fridman (1:53:49.340)

makes up life is the boring bits.

Katherine de Kleer (1:53:51.980)

If the boring bits aren't boring, then that's an exciting life because when you were talking

Lex Fridman (1:54:00.040)

so romantically and passionately about IO, I remember the poem by Robert Frost.

Lex Fridman (1:54:06.500)

So let me ask you, let me read the poem and ask what your opinion is.

Lex Fridman (1:54:11.500)

That's called Fire and Ice.

Katherine de Kleer (1:54:12.860)

Oh yeah.

Lex Fridman (1:54:13.860)

I could almost recite this from memory.

Katherine de Kleer (1:54:16.420)

Some say the world will end in fire.

Lex Fridman (1:54:18.300)

Some say in ice.

Katherine de Kleer (1:54:19.300)

From what I've tasted of desire, I hold with those who favor fire.

Lex Fridman (1:54:23.600)

But if I had to perish twice, I think I know enough of hate to say that for destruction

Katherine de Kleer (1:54:29.180)

ice is also great and would suffice.

Lex Fridman (1:54:33.020)

So let me ask, if you had to only choose one, would you choose the world to end in fire,

Lex Fridman (1:54:41.380)

in volcanic eruptions, in heat and magma, or in ice, frozen over?

Lex Fridman (1:54:51.180)

Fire or ice?

Katherine de Kleer (1:54:52.180)

Fire.

Lex Fridman (1:54:53.180)

Excellent choice.

Katherine de Kleer (1:54:54.180)

I've always been a fan of chaos and the idea of things just slowly getting cold and stopping

Lex Fridman (1:55:10.660)

and dying is just so depressing to me.

Lex Fridman (1:55:14.820)

So much more depressing than things blowing up or burning or getting covered by a lava

Lex Fridman (1:55:20.800)

flow.

Katherine de Kleer (1:55:21.800)

Somehow the activity of it endows it with more meaning to me, maybe.

Katherine de Kleer (1:55:27.500)

I've just now had this vision of you in action films where you're walking away without looking

Katherine de Kleer (1:55:32.100)

back and this explosion's behind you and you put on shades and then it goes to credits.

Lex Fridman (1:55:38.420)

Catherine, this is awesome, I think your work is really inspiring.

Katherine de Kleer (1:55:45.780)

The kind of things we'll discover about planets in the next few decades is super cool and

Katherine de Kleer (1:55:50.340)

I hope, I know you said there's probably not life in one of them, but there might be and

Katherine de Kleer (1:55:55.620)

I hope we discover just that.

Lex Fridman (1:55:58.380)

And perhaps even on Io, within the volcanic eruptions, there's a little creature hanging

Katherine de Kleer (1:56:04.020)

on that we'll one day discover.

Katherine de Kleer (1:56:06.340)

Thank you so much for wasting all your valuable time with me today, it was really awesome.

Katherine de Kleer (1:56:10.620)

Yeah, likewise, thank you for having me here.

Katherine de Kleer (1:56:14.340)

Thanks for listening to this conversation with Catherine Duclear and thank you to Fundrise,

Katherine de Kleer (1:56:19.140)

Blinkist, ExpressVPN and Magic Spoon.

Lex Fridman (1:56:23.180)

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Lex Fridman (1:56:26.460)

And now let me leave you with some words from Carl Sagan.

Katherine de Kleer (1:56:29.740)

On Titan, the molecules that have been raining down like mana from heaven for the last four

Katherine de Kleer (1:56:34.500)

billion years might still be there, largely unaltered, deep frozen, awaiting for the chemists

Lex Fridman (1:56:41.180)

from Earth.

Katherine de Kleer (1:56:42.800)

Thank you for listening and hope to see you next time.

Lex Fridman (20:05.740)

that look like?

Lex Fridman (20:06.740)

What would it feel like?

Lex Fridman (20:08.780)

Is this the entire thing covered in basically volcanoes?

Lex Fridman (20:15.560)

So it's interesting because there's very little atmosphere.

Katherine de Kleer (20:18.660)

The surface is actually really cold, very far below freezing on the surface when you're

Katherine de Kleer (20:23.300)

away from a volcano, but the volcanoes themselves are over a thousand degrees or the magma when

Lex Fridman (20:28.980)

it comes out is over a thousand degrees.

Lex Fridman (20:30.740)

And so.

Lex Fridman (20:31.740)

But it does come to the surface, the magma?

Katherine de Kleer (20:33.820)

It does.

Lex Fridman (20:34.820)

Yeah.

Katherine de Kleer (20:35.820)

In particular places.

Lex Fridman (20:36.820)

Whoa, that probably looks beautiful.

Lex Fridman (20:39.160)

So like, so it's frozen, not ice.

Lex Fridman (20:42.540)

Like what is, is rock, it's really cold rock.

Lex Fridman (20:46.380)

And then you just have this like, what is, what does that look, what would that look

Lex Fridman (20:51.340)

like with no atmosphere?

Lex Fridman (20:53.480)

Would that, uh, would it be smoke?

Lex Fridman (20:55.700)

What does it look like?

Lex Fridman (20:58.620)

It's just magma, like just red, yellow, like liquidy things?

Lex Fridman (21:03.420)

It's black, it's black and red, I guess.

Katherine de Kleer (21:06.500)

Like think of the type of magma that you see in Hawaii.

Lex Fridman (21:10.440)

So different types of magma flow in different ways, for example.

Lex Fridman (21:13.260)

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

Lex Fridman (21:19.740)

it has really low viscosity.

Lex Fridman (21:23.620)

And I think the lava flows that we've been having in Hawaii over the past couple of years

Katherine de Kleer (21:27.580)

are probably a decent analogy, although Io's magma's lavas are even more fluid and faster

Katherine de Kleer (21:35.020)

moving.

Lex Fridman (21:36.020)

How faster?

Katherine de Kleer (21:37.020)

Like what, uh, how fat, like if you, uh, by the way, sorry, through the telescope, are

Lex Fridman (21:41.580)

you tracking at what timescale?

Lex Fridman (21:43.620)

Like every frame is how far apart?

Katherine de Kleer (21:47.580)

If you're looking through a telescope, are we talking about seconds or we're talking

Katherine de Kleer (21:50.820)

about days, months, when you kind of track, try to get a picture of what the surface might

Lex Fridman (21:56.500)

look like, what's the frequency?

Lex Fridman (21:59.660)

So it depends a little bit on what you want to do.

Katherine de Kleer (22:03.020)

I, ideally every night, um, but you could take a frame every second and see how things

Katherine de Kleer (22:09.240)

are changing.

Katherine de Kleer (22:10.240)

The, the problem with that is that for things to change on a one second timescale, you to

Katherine de Kleer (22:16.300)

actually see something change that fast, you have to have super high resolution.

Lex Fridman (22:19.820)

The spatial resolution we have is a couple of hundred kilometers.

Lex Fridman (22:22.460)

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

Lex Fridman (22:28.260)

really crazy happening.

Lex Fridman (22:29.900)

So if you get, if you get a telescope closer to Io, if you get a, or a camera closer to

Lex Fridman (22:36.100)

Io, would you be able to understand something?

Lex Fridman (22:39.940)

Is that something of interest to you?

Katherine de Kleer (22:41.860)

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

Lex Fridman (22:46.300)

how magma flows and just the, like the rate of the magma is, or is it basically enough

Lex Fridman (22:52.920)

to have the kilometer resolution?

Lex Fridman (22:55.100)

Do you get it?

Lex Fridman (22:56.100)

No way.

Katherine de Kleer (22:57.100)

We want to go there.

Lex Fridman (22:58.100)

Absolutely.

Lex Fridman (22:59.100)

You want to go, you want to go to Io?

Katherine de Kleer (23:00.100)

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

Katherine de Kleer (23:02.660)

Absolutely.

Lex Fridman (23:03.660)

Why?

Lex Fridman (23:04.660)

Why are you scared?

Lex Fridman (23:05.660)

Why am I scared?

Katherine de Kleer (23:06.660)

Oh, you mean you don't like, I don't want to go there as a human as a human.

Lex Fridman (23:11.540)

I want to send a robot there to look at it though.

Katherine de Kleer (23:13.580)

This is again, everybody's discriminating against robots.

Lex Fridman (23:16.180)

This is not, but it's fine.

Lex Fridman (23:18.780)

But it's not hospitable to humans in any way, right?

Lex Fridman (23:22.320)

Just very cold and very hot.

Katherine de Kleer (23:24.780)

It's very cold.

Lex Fridman (23:27.380)

The atmosphere is composed of sulfur dioxide, so you can breathe it.

Katherine de Kleer (23:31.680)

There's no pressure.

Lex Fridman (23:32.680)

I mean, it's kind of all the same things you talk about.

Katherine de Kleer (23:34.860)

One talks about, about Mars only worse, the atmosphere is still a thousand times less

Lex Fridman (23:39.440)

dense than Mars is.

Lex Fridman (23:42.820)

And the radiation environment is terrible because you're embedded deep within Jupiter's

Katherine de Kleer (23:47.060)

magnetic field and Jupiter's magnetic field is full of charged particles that have all

Katherine de Kleer (23:53.060)

come out of Io's volcanoes actually.

Lex Fridman (23:56.460)

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

Katherine de Kleer (24:03.060)

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

Lex Fridman (24:07.540)

throughout the system actually.

Katherine de Kleer (24:08.900)

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

Lex Fridman (24:13.580)

Okay, cool.

Lex Fridman (24:15.700)

So what does studying Io teach you about volcanoes on earth or vice versa?

Lex Fridman (24:23.260)

Is in the difference of the two, what insights can you mine out?

Katherine de Kleer (24:30.900)

That might be interesting in some way.

Lex Fridman (24:34.900)

Yeah.

Katherine de Kleer (24:35.900)

Well, we try to port the tools that we use to study earth volcanism to Io and it works

Katherine de Kleer (24:41.540)

to some extent, but it is challenging because the situations are so different and the compositions

Katherine de Kleer (24:49.260)

are really different.

Katherine de Kleer (24:50.260)

When you talk about outgassing, you know, earth volcanoes outgassed primarily water

Lex Fridman (24:55.020)

and carbon dioxide, and then sulfur dioxide is the third most abundant gas.

Lex Fridman (25:00.540)

And on Io, the water and carbon dioxide are not there, either it didn't form with them

Katherine de Kleer (25:07.100)

or it lost them, we don't know.

Lex Fridman (25:09.620)

And so the chemistry of how the magma outgassed this is completely different.

Lex Fridman (25:14.220)

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

Katherine de Kleer (25:24.580)

it has these really low viscosity magmas, the lava spreads really quickly across its

Katherine de Kleer (25:29.580)

surface, it can put out massive volumes of magma in relatively short periods of time.

Lex Fridman (25:34.500)

And that sort of volcanism is not happening anywhere else in the solar system today.

Lex Fridman (25:39.220)

But literally every terrestrial planet and the moon had this, what we call very effusive

Lex Fridman (25:46.540)

volcanism early in their history.

Katherine de Kleer (25:48.580)

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

Lex Fridman (25:52.260)

Yeah.

Katherine de Kleer (25:53.260)

Okay, cool.

Lex Fridman (25:54.260)

So what are the chances that a volcano on earth destroys all of human civilization?

Katherine de Kleer (26:00.220)

Maybe I wanted to sneak in that question.

Lex Fridman (26:01.780)

Yeah, a volcano on earth.

Lex Fridman (26:06.020)

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

Katherine de Kleer (26:09.500)

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

Lex Fridman (26:15.380)

for humans, and then you realize we're sitting on many of them here?

Lex Fridman (26:18.980)

Right.

Katherine de Kleer (26:19.980)

Yeah, Yellowstone is a classic example.

Lex Fridman (26:22.300)

I don't know what the chances are of that happening.

Katherine de Kleer (26:26.740)

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

Katherine de Kleer (26:31.380)

wiped out by some other means, that maybe it'll happen eventually, that there'll be

Katherine de Kleer (26:37.580)

one of these massive volcanoes on earth, but we'll probably be gone by then by some other

Lex Fridman (26:41.060)

means.

Katherine de Kleer (26:42.060)

Not to sound bleak.

Lex Fridman (26:43.060)

That's very comforting.

Lex Fridman (26:44.060)

Okay, so can we talk about Europa?

Katherine de Kleer (26:51.060)

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

Lex Fridman (26:57.700)

life being in Europa?

Lex Fridman (27:00.140)

Maybe also, what are the things we know about it?

Lex Fridman (27:03.720)

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

Lex Fridman (27:08.540)

Sure.

Katherine de Kleer (27:09.540)

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

Lex Fridman (27:15.220)

system among the solar system moons.

Lex Fridman (27:16.960)

So there are a few, there's a lot of interest in looking for or understanding the potential

Lex Fridman (27:25.220)

for life to evolve in the subsurface oceans.

Katherine de Kleer (27:27.700)

I think it's fairly widely accepted that the chances of life evolving on the surfaces of

Lex Fridman (27:33.940)

really anything in the solar system is very low.

Katherine de Kleer (27:37.660)

The radiation environment is too harsh and there's just not liquids on the surface of

Katherine de Kleer (27:45.400)

most of these things and it's canonically accepted that liquids are required for life.

Lex Fridman (27:51.460)

And so the subsurface oceans, in addition to maybe Titan's atmosphere, the subsurface

Katherine de Kleer (27:55.620)

oceans of the icy satellites are one of the most plausible places in the solar system

Katherine de Kleer (28:01.260)

for life to evolve.

Katherine de Kleer (28:03.740)

Europa and Cellitus are interesting because for many of the big satellites, so Ganymede

Lex Fridman (28:08.780)

and Callisto, also satellites of Jupiter, also are thought to have subsurface oceans.

Lex Fridman (28:13.780)

But they have these ice shells and then there's an ocean underneath the ice shell.

Lex Fridman (28:19.380)

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

Lex Fridman (28:23.540)

and then there's rock.

Lex Fridman (28:25.580)

And the reason that that is a problem for life is that your ocean is probably just pure

Lex Fridman (28:30.640)

water because it's trapped between two big shells of ice.

Lex Fridman (28:34.740)

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

Lex Fridman (28:39.980)

And so the water and rock are in direct interaction and so that means that you can basically dissolve

Katherine de Kleer (28:45.500)

a lot of material out of the rock.

Katherine de Kleer (28:47.060)

You potentially have this hydrothermal activity that's injecting energy and nutrients for

Katherine de Kleer (28:52.840)

life to survive.

Lex Fridman (28:53.840)

And so this rock water interface is considered really important for the potential habitability.

Katherine de Kleer (29:02.500)

As a small aside, you kind of said that it's canonically assumed that water is required

Lex Fridman (29:08.940)

for life.

Lex Fridman (29:09.940)

Is it possible to have life like in a volcano?

Katherine de Kleer (29:13.700)

I remember people were like in that National Geographic program or something kind of hypothesizing

Katherine de Kleer (29:21.660)

that you can really have life anywhere.

Lex Fridman (29:23.700)

So as long as there's a source of heat, a source of energy, do you think it's possible

Lex Fridman (29:27.860)

to have life in a volcano, like no water?

Lex Fridman (29:34.580)

I think anything's possible.

Katherine de Kleer (29:37.780)

I think so.

Lex Fridman (29:39.740)

It doesn't have to be water.

Katherine de Kleer (29:42.660)

You can tell, as you identified, I phrased that really carefully.

Katherine de Kleer (29:46.100)

It's canonically accepted that because scientists recognize that we have no idea what broad

Katherine de Kleer (29:53.380)

range of life could be out there and all we really have is our biases of life as we know

Lex Fridman (29:57.780)

it.

Lex Fridman (29:58.780)

But for life as we know it, it's very helpful to have or even necessary to have some kind

Katherine de Kleer (30:02.820)

of liquid and preferably a polar solvent that can actually dissolve molecules, something

Katherine de Kleer (30:09.260)

like water.

Lex Fridman (30:10.260)

So the case of liquid methane on Titan is less ideal from that perspective.

Lex Fridman (30:14.100)

But liquid magma, if it stays liquid long enough for life to evolve, you have a heat

Lex Fridman (30:20.460)

source, you have a liquid, you have nutrients.

Katherine de Kleer (30:22.420)

In theory, that checks your three classic astrobiology boxes.

Lex Fridman (30:28.580)

That'd be fascinating.

Katherine de Kleer (30:29.580)

I mean, it'd be fascinating if it's possible to detect it easily.

Lex Fridman (30:32.580)

How would we detect if there is life on Europa?

Lex Fridman (30:38.780)

Is it possible to do in a noncontact way from a distance through telescopes and so on?

Lex Fridman (30:45.620)

Or do we need to send robots and do some drilling?

Katherine de Kleer (30:51.140)

I think realistically you need to do the drilling.

Lex Fridman (30:56.900)

So Europa also has these long tectonic features on its surface where it's thought that there's

Katherine de Kleer (31:02.580)

potential for water from the ocean to be somehow making its way up onto the surface.

Lex Fridman (31:08.180)

And you could imagine some out there scenario where there's bacteria in the ocean.

Katherine de Kleer (31:12.400)

It's somehow working its way up through the ice shell.

Lex Fridman (31:14.540)

It's spilling out on the surface.

Katherine de Kleer (31:16.200)

It's being killed by the radiation.

Lex Fridman (31:18.820)

But your instrument could detect some spectroscopic signature of that dead bacterium.

Lex Fridman (31:24.300)

But that's many ifs and assumptions.

Lex Fridman (31:26.980)

That's a hope because then you don't have to do that much drilling.

Katherine de Kleer (31:29.780)

You can collect from the surface.

Lex Fridman (31:32.100)

Skeletons of bacteria.

Katherine de Kleer (31:33.100)

Right.

Lex Fridman (31:34.100)

I'm thinking even remotely.

Katherine de Kleer (31:35.100)

Oh, remotely.

Lex Fridman (31:36.100)

Yeah.

Katherine de Kleer (31:37.100)

That's sad that there's a single cell civilization living underneath all that ice trying to get

Lex Fridman (31:45.580)

up.

Katherine de Kleer (31:46.580)

Trying to get out.

Katherine de Kleer (31:47.580)

Enceladus gives you a slightly better chance of that because Enceladus is a moon of Saturn

Lex Fridman (31:55.220)

and it's broadly similar to Europa in some ways.

Lex Fridman (31:59.580)

It's an icy satellite.

Katherine de Kleer (32:00.580)

It has a subsurface ocean that's probably in touch with the rocky interior.

Lex Fridman (32:05.500)

But it has these massive geysers at its south pole where it's spewing out material that

Katherine de Kleer (32:09.820)

appears to be originating all the way from the ocean.

Lex Fridman (32:12.940)

And so in that case, you could potentially fly through that plume and scoop up that material

Lex Fridman (32:20.100)

and hope that at the velocities you'd be scooping it up.

Lex Fridman (32:22.700)

You're not destroying any signature of the life you're looking for.

Lex Fridman (32:27.060)

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

Katherine de Kleer (32:31.500)

It potentially gives you a more direct opportunity at least to try to measure those bacteria

Katherine de Kleer (32:38.260)

directly.

Lex Fridman (32:39.260)

Can you tell me a little more on, how do you pronounce it, Salas?

Katherine de Kleer (32:45.100)

Enceladus.

Lex Fridman (32:46.100)

Enceladus.

Lex Fridman (32:47.100)

Can you tell me a little bit more about Enceladus?

Katherine de Kleer (32:49.780)

Like we've been talking about way too much about Jupiter, Saturn doesn't get enough love.

Katherine de Kleer (32:58.100)

Saturn doesn't get as much love.

Lex Fridman (32:59.380)

So what's Enceladus?

Lex Fridman (33:02.060)

Is that the most exciting moon of Saturn?

Lex Fridman (33:05.300)

Depends on your perspective.

Katherine de Kleer (33:07.760)

It's very exciting from a astrobiology perspective.

Katherine de Kleer (33:11.380)

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

Katherine de Kleer (33:16.860)

definitely both get the most attention also from the life perspective.

Lex Fridman (33:22.460)

So what's the more likely Titan or Enceladus for life?

Katherine de Kleer (33:28.500)

If you were to bet all your money in terms of like investing, which to investigate, what

Lex Fridman (33:33.580)

are the differences between the two that are interesting to you?

Katherine de Kleer (33:37.260)

Yeah.

Lex Fridman (33:38.260)

So the potential for life in each of those two places is very different.

Lex Fridman (33:43.260)

So Titan is the one place in the solar system where you might imagine, again, all of this

Lex Fridman (33:48.840)

is so speculative, but you might imagine life evolving in the atmosphere.

Lex Fridman (33:53.380)

So from a biology perspective, Titan is interesting because it forms complex organic molecules

Lex Fridman (33:59.900)

in its atmosphere.

Katherine de Kleer (34:01.740)

It has a dense atmosphere.

Lex Fridman (34:02.820)

It's actually denser than Earth's.

Katherine de Kleer (34:04.360)

It's the only moon that has an atmosphere denser than Earth's and it's got tons of methane

Lex Fridman (34:09.660)

in it.

Lex Fridman (34:10.660)

What happens is that methane gets irradiated, it breaks up and it reforms with other things

Lex Fridman (34:13.920)

in the atmosphere.

Katherine de Kleer (34:15.500)

It makes these complex organic molecules and it's effectively doing prebiotic chemistry

Lex Fridman (34:21.640)

in the atmosphere.

Lex Fridman (34:23.460)

While still being freezing cold?

Lex Fridman (34:25.540)

Yes.

Katherine de Kleer (34:26.540)

Okay.

Lex Fridman (34:27.540)

What would that be like?

Lex Fridman (34:29.740)

Would that be pleasant for humans to hang out there?

Lex Fridman (34:32.900)

It's just really cold?

Katherine de Kleer (34:34.200)

There's nowhere in the solar system that would be pleasant for humans.

Lex Fridman (34:37.820)

It would be cold.

Katherine de Kleer (34:38.820)

You couldn't breathe the air.

Lex Fridman (34:40.620)

But colonization wise, if there's an atmosphere, isn't that a big plus?

Lex Fridman (34:44.900)

Or still a ton of radiation?

Lex Fridman (34:47.860)

Sure.

Katherine de Kleer (34:48.860)

Okay.

Lex Fridman (34:49.860)

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

Katherine de Kleer (34:55.740)

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

Lex Fridman (35:01.220)

Okay.

Lex Fridman (35:02.740)

So what about Enceladus?

Lex Fridman (35:05.260)

So that would be still in the ocean.

Katherine de Kleer (35:07.780)

Right.

Lex Fridman (35:08.780)

And Enceladus has the advantage, like I said, of spewing material out of its south pole

Lex Fridman (35:13.300)

so you could collect it.

Lex Fridman (35:14.300)

But it has the disadvantage of the fact that we don't actually really understand how its

Katherine de Kleer (35:21.220)

ocean could stay globally liquid over the age of the solar system.

Lex Fridman (35:28.020)

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

Katherine de Kleer (35:34.860)

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

Lex Fridman (35:40.780)

in and out of these eccentricities.

Lex Fridman (35:45.020)

And in that case, the potential for life ever occurring there in the first place is a lot

Lex Fridman (35:49.540)

lower because if you only have an ocean for 100 million years, is that enough time?

Katherine de Kleer (35:55.020)

It also means there might be mass extinction events if it does occur and then it just freezes.

Lex Fridman (36:00.580)

Again, very sad, man.

Katherine de Kleer (36:01.580)

This is very depressing, all the slaughter of life elsewhere.

Lex Fridman (36:07.620)

How unlikely do you think life is on Earth?

Lex Fridman (36:11.900)

So when you study other planets and you study the contents of other planets, does that give

Katherine de Kleer (36:18.780)

you a perspective on the origin of life on Earth, which again is full of mystery in itself,

Katherine de Kleer (36:26.020)

not the evolution, but the origin, the first springing to life, like from nothing to life,

Lex Fridman (36:33.900)

from the basic ingredients to life?

Lex Fridman (36:37.380)

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

Katherine de Kleer (36:40.620)

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

Katherine de Kleer (36:46.580)

to.

Katherine de Kleer (36:47.640)

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

Katherine de Kleer (36:53.040)

independently a thousand times in different places.

Katherine de Kleer (36:56.560)

We don't know whether it's happened anywhere else in the universe, although it feels absurd

Katherine de Kleer (37:01.840)

to believe that we are the only life that evolved in the entire universe, but it's conceivable.

Lex Fridman (37:07.540)

We just have just no real information.

Katherine de Kleer (37:12.060)

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

Katherine de Kleer (37:15.740)

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

Katherine de Kleer (37:23.620)

are out there, planets have a big part to play in that equation.

Katherine de Kleer (37:29.700)

If you were to bet money in terms of the odds of origins of life on Earth, I mean, this

Katherine de Kleer (37:36.500)

all has to do with how special and unique is Earth.

Lex Fridman (37:40.220)

What you land in terms of the number of civilizations has to do with how unique their rare Earth

Katherine de Kleer (37:45.720)

hypothesis is.

Lex Fridman (37:47.000)

How rare and special is Earth?

Lex Fridman (37:49.640)

How rare and special is the solar system?

Katherine de Kleer (37:52.740)

Like if you had to bet all your money on a completely unscientific question, well, no,

Katherine de Kleer (37:58.500)

it's actually a rigorously scientific, we just don't know a lot of things in that equation.

Katherine de Kleer (38:03.340)

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

Katherine de Kleer (38:08.020)

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

Lex Fridman (38:13.500)

planets that are Earth like planets, it's getting better and better understood.

Katherine de Kleer (38:16.700)

What's your sense from that perspective, how many alien civilizations out there, zero or

Lex Fridman (38:24.780)

one plus?

Katherine de Kleer (38:25.780)

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

Lex Fridman (38:30.420)

about the first three parameters in the equation or something.

Lex Fridman (38:33.500)

How many stars are there, how many planets per star, and then we're just barely scratching

Lex Fridman (38:38.380)

the surface of what fraction of those planets might be habitable.

Katherine de Kleer (38:41.820)

The rest of the terms in the equation are like how likely is life to evolve given habitable

Lex Fridman (38:46.460)

conditions, how likely is it to survive, all these things.

Katherine de Kleer (38:51.480)

There are all these huge unknowns.

Katherine de Kleer (38:53.160)

Actually I remember when I first saw that equation, I think it was my first year of

Katherine de Kleer (38:58.860)

college and I thought this is ridiculous.

Katherine de Kleer (39:01.420)

This is A, common sense that didn't need to give a name, you know, and B, just a bunch

Katherine de Kleer (39:08.660)

of unknowns, it's like putting our ignorance together in one equation.

Lex Fridman (39:12.340)

But now I understand this equation, you know, it's not something we'll ever necessarily

Katherine de Kleer (39:17.860)

have the answer to, it just gives us a framework for having the exact conversation we're having

Lex Fridman (39:22.900)

right now.

Lex Fridman (39:23.900)

And I think that's how it was intended in the first place when it was put into writing

Katherine de Kleer (39:27.660)

was to give people a language to communicate about the factors that go into the potential

Katherine de Kleer (39:33.020)

for aliens to be out there and for us to find them.

Katherine de Kleer (39:38.100)

I would put money on there being aliens, I would not put money on us having definitive

Katherine de Kleer (39:46.740)

evidence of them in my lifetime.

Lex Fridman (39:49.740)

Well, definitive is a funny, is a funny word.

Katherine de Kleer (39:54.700)

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

Katherine de Kleer (40:01.500)

civilizations, I feel like we're so, we're so self obsessed that we literally would not

Katherine de Kleer (40:11.100)

be able to detect them.

Katherine de Kleer (40:13.340)

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

Katherine de Kleer (40:20.020)

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

Lex Fridman (40:28.780)

Like trees could be way more intelligent than us.

Katherine de Kleer (40:31.700)

I don't know.

Lex Fridman (40:32.700)

It's just a dumb example.

Katherine de Kleer (40:33.700)

It could be rocks or it could be things like, this, I love this, this is a Dawkins memes.

Lex Fridman (40:41.260)

It could be that ideas are the, like ideas we have, like where do ideas come from?

Lex Fridman (40:46.460)

Where do thoughts come from?

Katherine de Kleer (40:48.140)

Maybe thoughts are the aliens or maybe thoughts is the actual mechanisms of communication

Lex Fridman (40:55.840)

in physics, right?

Katherine de Kleer (40:57.700)

This is like, we think of thoughts as something that springs up from neurons firing or where

Katherine de Kleer (41:03.060)

the hell they come from.

Lex Fridman (41:05.340)

And now what about consciousness?

Katherine de Kleer (41:08.160)

Maybe consciousness is the communication.

Katherine de Kleer (41:10.560)

It sounds like ridiculous, but like we're so self centered on this space, time, communication

Lex Fridman (41:18.540)

and physical space using like written language, like spoken with audio on a time scale that's

Lex Fridman (41:26.780)

very specific on a physical scale, it's very specific.

Lex Fridman (41:30.960)

So I tend to think that, but bacteria will probably recognize like moving organisms will

Katherine de Kleer (41:37.620)

probably recognize, but when that forms itself into intelligence, most likely it'll be robots

Katherine de Kleer (41:42.700)

of some kind because we won't be meeting the origins.

Lex Fridman (41:45.620)

We'll be meeting the creations of those intelligences.

Katherine de Kleer (41:49.140)

We just would not be able to appreciate it.

Lex Fridman (41:51.340)

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

Katherine de Kleer (42:02.820)

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

Lex Fridman (42:07.300)

so much.

Katherine de Kleer (42:08.460)

The sad thing it could be that we're just like in the first 0.0001% of understanding

Lex Fridman (42:13.640)

anything is humbling.

Katherine de Kleer (42:15.060)

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

Lex Fridman (42:20.880)

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

Katherine de Kleer (42:25.700)

someday achieve.

Lex Fridman (42:26.700)

That actually feels optimistic to me.

Katherine de Kleer (42:29.540)

Well, I feel like that's easier for us to comprehend in the space of biology and not

Katherine de Kleer (42:35.020)

as easy to comprehend in the space of physics, for example, because we have a sense that

Katherine de Kleer (42:39.260)

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

Katherine de Kleer (42:45.460)

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

Lex Fridman (42:54.180)

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

Katherine de Kleer (42:58.380)

Biologists are like, uh, this is a squishy mess, we're doing our best, physicists, but

Katherine de Kleer (43:06.640)

I would be, it'd be fascinating to see if physicists themselves would also be humbled

Lex Fridman (43:10.580)

by their being like, what the hell is dark matter and dark energy?

Lex Fridman (43:15.940)

What the hell is the, not just the origin of the, not just the big bang, but everything

Lex Fridman (43:21.900)

that happened since the big bang.

Katherine de Kleer (43:24.180)

A lot of things that happened since the big bang, we have no ideas about except basic

Lex Fridman (43:27.320)

models of physics.

Katherine de Kleer (43:28.320)

Right.

Lex Fridman (43:29.320)

What happened before the big bang?

Katherine de Kleer (43:30.320)

Yeah.

Lex Fridman (43:31.320)

Yeah.

Lex Fridman (43:32.320)

What happened before?

Lex Fridman (43:33.320)

Or what's happening inside the black hole?

Lex Fridman (43:34.320)

Why is there a black hole at the center of our galaxy?

Lex Fridman (43:36.460)

Can somebody answer this?

Katherine de Kleer (43:37.460)

A supermassive black hole.

Lex Fridman (43:39.660)

Nobody knows how it started.

Lex Fridman (43:41.500)

And they seem to be like in the middle of all galaxies.

Lex Fridman (43:44.460)

Um, so that could be a portal for aliens to communicate through consciousness.

Katherine de Kleer (43:48.700)

Okay.

Lex Fridman (43:49.700)

Um, all right, back to planets.

Lex Fridman (43:51.700)

How, um, what's your favorite outside of earth?

Lex Fridman (43:55.300)

What's your favorite planet or moon?

Katherine de Kleer (43:57.740)

Maybe outside of the ones we, well, first, have we talked about it already or, and then

Lex Fridman (44:03.500)

if we did mention it, what's the one outside of that?

Katherine de Kleer (44:05.980)

Oh gosh.

Lex Fridman (44:06.980)

I have to come up with another favorite that's not IO.

Katherine de Kleer (44:08.980)

Oh, IO is the favorite.

Lex Fridman (44:09.980)

Oh, absolutely.

Lex Fridman (44:10.980)

Why is IO the favorite?

Katherine de Kleer (44:12.540)

I mean, basically everything I've, I've already said, it's just such a, an amazing and unique

Katherine de Kleer (44:17.540)

object.

Katherine de Kleer (44:18.540)

Um, but on, I guess a personal note, it's probably the object that made me become a

Katherine de Kleer (44:26.700)

planetary scientist.

Katherine de Kleer (44:28.660)

It's the first thing in the solar system that really deeply captured my interest.

Katherine de Kleer (44:34.260)

Um, and when I started my PhD, I wanted to be an astrophysicist working on things like

Katherine de Kleer (44:42.620)

galaxy evolution, um, and sort of slowly, I had done some projects in the solar system,

Lex Fridman (44:48.380)

but IO was the thing that like really caught me in to doing solar system science.

Lex Fridman (44:53.060)

Okay.

Katherine de Kleer (44:54.060)

Let's, let's leave, uh, moons aside.

Lex Fridman (44:56.980)

What's your favorite planet?

Katherine de Kleer (44:58.920)

It sounds like you like moons better than planets.

Lex Fridman (45:01.140)

So it's, uh, that's accurate.

Katherine de Kleer (45:02.940)

Um, but the planets are, are fascinating.

Katherine de Kleer (45:05.700)

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

Lex Fridman (45:10.540)

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

Katherine de Kleer (45:17.020)

There's still a lot more discovery space and the questions that we can ask are still the,

Katherine de Kleer (45:21.380)

the bigger questions.

Lex Fridman (45:22.380)

Gotcha.

Katherine de Kleer (45:23.380)

Um, which, you know, I, and maybe I'm being unfair to the planets because we're still

Lex Fridman (45:27.820)

trying to understand things like, was there ever life on Mars?

Lex Fridman (45:31.580)

And that is a huge question and one that we've sent numerous robots to Mars to try to answer.

Lex Fridman (45:37.460)

So maybe I'm being unfair to the planets, but, but there is certainly quite a bit more

Katherine de Kleer (45:41.220)

information, uh, that we have about the planets than the moons.

Lex Fridman (45:44.820)

But I mean, Venus is, is a fascinating object.

Lex Fridman (45:48.260)

So I like the objects that lie at the extremes.

Katherine de Kleer (45:53.340)

I think that if we can make a sort of theory or, or like I've been saying, framework for

Katherine de Kleer (45:59.420)

understanding planets and moons that can incorporate even the most extreme ones, then, you know,

Lex Fridman (46:04.380)

those are the things that really test your theory and test your understanding.

Lex Fridman (46:08.240)

And so they've always really fascinated me.

Katherine de Kleer (46:10.400)

Not so much the nice habitable places like Earth, but these extreme places like Venus

Katherine de Kleer (46:15.140)

that have, um, sulfuric acid clouds and just incredibly hot and dense surfaces.

Lex Fridman (46:23.620)

And Venus, of course, I love volcanism for some reason, and, and Venus has, probably

Katherine de Kleer (46:30.120)

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

Lex Fridman (46:37.020)

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

Lex Fridman (46:41.940)

in the atmosphere of Venus?

Lex Fridman (46:44.180)

Is that, sorry.

Katherine de Kleer (46:45.180)

Okay.

Lex Fridman (46:46.180)

You have opinion.

Katherine de Kleer (46:47.180)

I can already tell you have opinions.

Lex Fridman (46:49.100)

Was that fake news?

Katherine de Kleer (46:50.100)

I got excited when I saw that.

Lex Fridman (46:52.740)

What's the, what's the final, uh, is there a life on Venus?

Lex Fridman (46:56.460)

So the detection that was reported was the detection of the molecule phosphine.

Katherine de Kleer (47:01.020)

Um, and they said that they tried every other mechanism they could think of to produce phosphine

Lex Fridman (47:10.340)

and they, none of, no mechanism worked.

Lex Fridman (47:13.680)

And then they said, well, we know that life produces phosphine.

Lex Fridman (47:16.500)

And so that was sort of the train of logic.

Katherine de Kleer (47:19.540)

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

Katherine de Kleer (47:25.980)

Okay.

Lex Fridman (47:26.980)

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

Katherine de Kleer (47:35.500)

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

Lex Fridman (47:41.260)

from remotely and making conclusive statements about life.

Katherine de Kleer (47:46.740)

Oh yeah.

Katherine de Kleer (47:48.140)

Well that connection that you just made, the contents of the atmosphere to the life is,

Katherine de Kleer (47:53.500)

is a tricky one.

Lex Fridman (47:54.700)

And yeah, I know that that claim received a lot of criticism for the lines of logic

Katherine de Kleer (48:00.260)

that went from detection to, uh, to claim of life.

Katherine de Kleer (48:05.060)

Even the detection itself though, did, doesn't, doesn't meet the sort of historical scientific

Katherine de Kleer (48:11.760)

standards of, of a detection.

Katherine de Kleer (48:14.580)

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

Lex Fridman (48:20.820)

And a lot of really complicated data analysis methods had to be applied to even make that

Lex Fridman (48:26.600)

weak detection.

Katherine de Kleer (48:27.600)

Yeah.

Lex Fridman (48:28.600)

Um.

Lex Fridman (48:29.600)

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

Lex Fridman (48:32.660)

those things.

Lex Fridman (48:33.660)

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

Lex Fridman (48:38.100)

But of course, I mean, we're doing our best and it's clear that, uh, the human species

Katherine de Kleer (48:44.500)

are hopeful to find life.

Lex Fridman (48:46.940)

Clearly.

Katherine de Kleer (48:47.940)

Yes.

Lex Fridman (48:48.940)

Everyone is so excited about that possibility.

Katherine de Kleer (48:50.580)

All right.

Lex Fridman (48:51.580)

Let's, uh, let me ask you about Mars.

Katherine de Kleer (48:56.420)

So, um, there's a guy named Elon Musk and, uh, he seems to want to take something called

Lex Fridman (49:05.940)

Dogecoin there.

Katherine de Kleer (49:07.500)

First of the month.

Lex Fridman (49:08.500)

I'm just, I'm just kidding about the Dogecoin.

Katherine de Kleer (49:11.340)

I don't even know what the heck is up with that whole, um, I think, uh, I think humor

Katherine de Kleer (49:20.220)

has power in the 21st century in a way to spread ideas in the most positive way.

Lex Fridman (49:28.580)

So I love that kind of humor because it makes people smile, but it also kind of sneaks.

Lex Fridman (49:37.280)

It's like a Trojan horse for cool ideas.

Katherine de Kleer (49:40.740)

You you open with humor and you, uh, like the humor is the appetizer.

Lex Fridman (49:45.580)

And then the main meal is the science and the engineering anyway, uh, do you think it's

Katherine de Kleer (49:52.860)

possible to colonize Mars or other planets in the solar system, but we're especially

Lex Fridman (50:02.500)

looking to Mars.

Lex Fridman (50:04.300)

Is there something about planets that make them very harsh to humans?

Katherine de Kleer (50:09.100)

Is there something in particular you think about and maybe in a high like big picture

Lex Fridman (50:14.020)

perspective, do you have a hope we, we do in fact become a multi planetary species?

Katherine de Kleer (50:19.740)

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

Katherine de Kleer (50:26.820)

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

Lex Fridman (50:32.940)

planets.

Katherine de Kleer (50:33.940)

I do not expect that to happen in my lifetime.

Katherine de Kleer (50:36.380)

I mean, tourists may go to Mars, tourists, people who commit years of their life to go

Katherine de Kleer (50:41.260)

into Mars as a tourist may go to Mars.

Lex Fridman (50:43.820)

Um, I don't think that we will colonize it.

Katherine de Kleer (50:46.820)

Um, is there a sense why it's just too harsh on the environment to, uh, to, to, like it's

Lex Fridman (50:53.540)

too costly to build something habitable there for a large population.

Katherine de Kleer (51:00.260)

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

Lex Fridman (51:06.260)

are on the planet already to do the things we need.

Lex Fridman (51:09.540)

So if you're talking about someone going there for a few months, um, so we'll back up a little

Lex Fridman (51:16.460)

bit.

Katherine de Kleer (51:17.600)

There are many things that make Mars not hospitable, temperature, you can't breathe the air, you

Katherine de Kleer (51:22.820)

need a pressure suit, even if you're on the surface, the radiation environment is, you

Katherine de Kleer (51:27.420)

know, even in all of those things, the radiation environment is too harsh for the human body.

Katherine de Kleer (51:31.580)

Um, all of those things seem like they could eventually have technological solutions.

Katherine de Kleer (51:37.940)

Um, the challenge, the, the real significant challenge to me seems to be the, the creation

Lex Fridman (51:46.220)

of a self sustaining civilization there.

Katherine de Kleer (51:49.540)

You know, you can bring pressure suits, you can bring oxygen to breathe, but those are

Lex Fridman (51:53.880)

all in limited supply.

Lex Fridman (51:55.220)

And if we're going to colonize it, we need to find ways to make use of the resources

Katherine de Kleer (51:59.760)

that are there to do things like produce food, produce the air, the humans need to keep breathing

Katherine de Kleer (52:05.100)

just in order to make it self sustaining.

Lex Fridman (52:07.140)

There's a tremendous amount of work that has to be done.

Lex Fridman (52:09.620)

And people are working on these problems, but I think that's going to be a major obstacle

Katherine de Kleer (52:15.420)

in going from visiting where we can bring everything we need to survive in the short

Katherine de Kleer (52:19.780)

term to actually colonizing.

Lex Fridman (52:21.780)

Yeah.

Katherine de Kleer (52:22.780)

I find that whole project of the human species quite inspiring these like huge moonshot projects.

Katherine de Kleer (52:33.400)

Somebody I was reading something, um, in terms of the source of food that's that may be the

Katherine de Kleer (52:38.580)

most effective on Mars is you could farm insects.

Lex Fridman (52:42.860)

That's the easiest thing to farm.

Lex Fridman (52:44.980)

So we'd be eating like cockroaches before living on Mars because that's the easiest

Lex Fridman (52:50.740)

thing to actually, um, as a source of protein.

Lex Fridman (52:54.620)

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

Lex Fridman (52:57.860)

I just imagine this giant for people who are afraid of insects.

Katherine de Kleer (53:03.160)

This is not a pleasant, maybe you're not supposed to even think of it that way.

Lex Fridman (53:07.180)

It'd be like a cockroach milkshake or something like that.

Katherine de Kleer (53:09.780)

Right.

Katherine de Kleer (53:10.780)

I wonder if, have people been working on the genetic engineering of, of insects to make

Katherine de Kleer (53:15.420)

them radiation friendly, right.

Lex Fridman (53:19.060)

Or pressure resistant or whatever.

Lex Fridman (53:22.540)

What can possibly go wrong with making radiation resistant, they're already like survived everything.

Lex Fridman (53:29.620)

Plus I, um, I took an allergy test, um, in Austin.

Lex Fridman (53:32.900)

So there's everybody's alert is like the allergy levels are super high there.

Katherine de Kleer (53:36.820)

Uh, and, uh, one of the things, apparently I'm not allergic to any insects except cockroaches.

Katherine de Kleer (53:43.020)

It's hilarious.

Lex Fridman (53:44.380)

So maybe, uh, um, well, I'm going to use that as a, you know, people use, uh, an excuse

Katherine de Kleer (53:50.920)

that I'm allergic to cats to not have cats.

Katherine de Kleer (53:52.780)

I'm going to use that as an excuse to, uh, not go to Mars as one of the first batch of

Katherine de Kleer (53:56.980)

people.

Lex Fridman (53:57.980)

I was going to ask if you had the opportunity, would you go?

Katherine de Kleer (54:00.740)

Yeah, I'm joking about the cockroach thing.

Lex Fridman (54:03.080)

I would definitely go.

Katherine de Kleer (54:04.080)

I love challenges.

Lex Fridman (54:05.220)

I love, I love things.

Katherine de Kleer (54:08.260)

I love doing things where the possibility of death is, is, uh, not insignificant because

Lex Fridman (54:17.500)

it makes me appreciate it more.

Katherine de Kleer (54:22.740)

Meditating on death makes me appreciate life.

Lex Fridman (54:27.780)

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

Katherine de Kleer (54:35.660)

I enjoy those kinds of things.

Katherine de Kleer (54:37.900)

Most people don't, it seems like, but I love the idea of difficult journeys, um, for no

Katherine de Kleer (54:44.060)

purpose whatsoever, except exploration, going into the unknown, seeing what the limits of

Katherine de Kleer (54:50.780)

the human mind and the human body are is like, what the hell else is this whole journey that

Lex Fridman (54:55.460)

we're on for?

Lex Fridman (54:56.460)

I, I, uh, but it could be because I grew up in the Soviet Union.

Katherine de Kleer (55:00.380)

There's a kind of love for space, like the, the space race, the cold war created.

Katherine de Kleer (55:07.140)

I don't know if still it permeates American culture as much, but especially with the dad

Katherine de Kleer (55:13.020)

as a scientist, I think I've, I've loved the idea of humans striving out towards the stars

Lex Fridman (55:20.460)

always, like from the engineering perspective has been really exciting.

Katherine de Kleer (55:24.900)

I don't know if people love that as much in America anymore.

Katherine de Kleer (55:27.020)

I think, uh, Elon is bringing that back a little bit, that excitement about rockets

Lex Fridman (55:31.860)

and going out there.

Lex Fridman (55:33.940)

But, uh, so that's, that's hopeful, but for me, I always loved that idea.

Katherine de Kleer (55:38.180)

From a alien scientist perspective, if you were to look back on earth, is there something

Lex Fridman (55:47.140)

interesting you could say about earth?

Lex Fridman (55:49.180)

Like, how would you summarize earth?

Katherine de Kleer (55:51.060)

Like in a report, you know, like, uh, Hitchhiker's Guide to the Galaxy, like if you had to report,

Katherine de Kleer (55:57.180)

like write a paper on earth or like a letter, like a, like a one pager, um, summarizing

Lex Fridman (56:03.580)

the contents of the surface and the atmosphere, is there, is there something interesting?

Lex Fridman (56:06.700)

Like, do you ever take that kind of perspective on it?

Lex Fridman (56:11.140)

I know you like volcanism, so volcanoes that will probably be in the report.

Katherine de Kleer (56:14.860)

I was going to say that's where I was going to go first.

Katherine de Kleer (56:17.020)

Uh, there are a few things to say about the atmosphere, but in terms of the volcanoes,

Lex Fridman (56:20.560)

so one of the really interesting puzzles to me in planetary science is so we can, we can

Katherine de Kleer (56:28.300)

look out there and we've been talking about surfaces and volcanoes and atmospheres and

Katherine de Kleer (56:32.580)

things like that.

Lex Fridman (56:33.860)

But that is just, you know, this tiny little veneer on the outside of the planet and most

Katherine de Kleer (56:38.100)

of the planet is completely sort of inaccessible to telescopes or to spacecraft missions.

Katherine de Kleer (56:43.260)

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

Katherine de Kleer (56:47.580)

Um, and one of the cool puzzles is looking at what's going on on the surface and trying

Katherine de Kleer (56:53.500)

to figure out what's happening underneath or just any kind of indirect means that you

Katherine de Kleer (56:59.400)

have to study the interior because you can't dig into it directly, even on Earth.

Lex Fridman (57:03.940)

You can't dig deep into Earth.

Katherine de Kleer (57:06.300)

Uh, so from that perspective, looking at Earth, um, one thing that you would be able to tell

Lex Fridman (57:13.020)

from orbit, given enough time, is that Earth has tectonic plates.

Lex Fridman (57:18.760)

So you would see that volcanoes follow the edges.

Katherine de Kleer (57:22.940)

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

Katherine de Kleer (57:27.040)

the edges of the plates.

Lex Fridman (57:28.300)

And similarly, you would see things like the, uh, Hawaiian string of volcanoes that you

Katherine de Kleer (57:34.700)

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

Lex Fridman (57:39.260)

plates are moving over some plume that's coming up through the mantle.

Lex Fridman (57:43.260)

And so you could use that to say, if the aliens could look at where the volcanoes are, are

Katherine de Kleer (57:48.180)

happening on Earth and say something about the fact that Earth has plate tectonics, which

Katherine de Kleer (57:51.780)

makes it really unique in the solar system.

Lex Fridman (57:54.180)

Um...

Lex Fridman (57:55.180)

Oh, really?

Lex Fridman (57:56.180)

So the other planets don't have plate tectonics?

Katherine de Kleer (57:57.180)

It's the only one that has plate tectonics.

Lex Fridman (57:58.660)

Yeah.

Lex Fridman (57:59.660)

What about Io and the friction and all that, that's not plate tectonics?

Lex Fridman (58:03.740)

What's the difference between...

Katherine de Kleer (58:04.740)

Oh, it's plate tectonics, like another layer of like solid rock that moves around and there's

Lex Fridman (58:11.500)

cracks.

Katherine de Kleer (58:12.500)

Exactly.

Lex Fridman (58:13.500)

Yeah.

Katherine de Kleer (58:14.500)

So, so Earth has plates of solid rock sitting on top of a partially molten layer, and those

Lex Fridman (58:19.660)

plates are kind of shifting around.

Katherine de Kleer (58:22.060)

Um, on Io, it doesn't have that.

Lex Fridman (58:26.060)

And the volcanism is what we call heat pipe volcanism.

Katherine de Kleer (58:28.900)

It's the magma just punches a hole through the crust and comes out on the surface.

Lex Fridman (58:32.780)

I mean, that's a simplification, but that's effectively what's happening.

Lex Fridman (58:35.780)

Through the freezing cold crust?

Lex Fridman (58:38.220)

Yes.

Katherine de Kleer (58:39.220)

Very cold, very rigid crust.

Lex Fridman (58:41.380)

Yeah.

Lex Fridman (58:42.380)

How do you, how does that look like, by the way?

Katherine de Kleer (58:44.380)

I don't think we've mentioned, so the gas that's expelled, like if we were to look at

Lex Fridman (58:49.540)

it, is it beautiful or is it like boring?

Lex Fridman (58:51.940)

The gas?

Katherine de Kleer (58:52.940)

I mean, the whole thing, like the magma punching through, the icy...

Lex Fridman (58:56.740)

Oh my gosh.

Katherine de Kleer (58:57.740)

Yes, I'm sure it would be beautiful, and the pictures we've seen of it are beautiful.

Katherine de Kleer (59:00.700)

You have, so the magma will come out of the lava, will come out of these fissures, and

Katherine de Kleer (59:07.620)

you have these curtains of lava that are maybe even a kilometer high.

Lex Fridman (59:13.620)

So if you looked at videos, I don't know how many volcano videos you've looked at on Earth,

Lex Fridman (59:17.660)

but you sometimes see a tiny, tiny version of this in Iceland.

Katherine de Kleer (59:20.500)

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

Katherine de Kleer (59:24.380)

low viscosity magma, sort of water like, coming out of these sheets.

Lex Fridman (59:29.900)

And the plumes that come out, because there's no atmosphere, all the plume molecules are

Katherine de Kleer (59:35.420)

just plume particles, where they end up is just a function of the direction that they

Katherine de Kleer (59:42.820)

left the vent, so they're all following ballistic trajectories, and you end up with these umbrella

Katherine de Kleer (59:47.940)

plumes.

Katherine de Kleer (59:48.940)

You don't get these sort of complicated plumes that you have on Earth that are occurring

Katherine de Kleer (59:53.180)

because of how that material is interacting with the atmosphere that's there.

Katherine de Kleer (59:56.740)

You just have these huge umbrellas, and it's been hypothesized, actually, that the atmosphere