The following is a conversation with Catherine DeCleer, a professor of Planetary Science and
Astronomy at Caltech. Her research is on the surface environments, atmospheres,
and thermochemical histories of the planets and moons in our solar system.
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As a side note, let me say that this conversation and a few others, quite big ones actually,
that are coming up or filmed in a studio where I was trying to outsource some of the work.
Like all experiments, it was a learning experience for me. It had some positives
and negatives. Ultimately, I decided to return back to doing it the way I was doing before,
but hopefully with a team who can help me out and work with me long term. The point is, I will
always keep challenging myself, trying stuff out, learning, growing, and hopefully improving over
time. My goal is to surround myself with people who love what they do, are amazing at it, and are
obsessed with doing the best work of their lives. To me, there's nothing more energizing and fun
than that. In fact, I'm currently hiring a few folks to work with me on very small projects.
If this is something of interest to you, go to lexfreedman.com slash hiring. That's where I
will always post opportunities for working with me. This is the Lex Freedman podcast,
and here is my conversation with Catherine DeClear. Why is Pluto not a planet anymore?
Does this upset you or has justice finally been served?
So I get asked this all the time. I think all planetary scientists get asked about Pluto,
especially by kids who we just love for Pluto to still be a planet. But the reality is, when we
first discovered Pluto, it was a unique object in the outer solar system, and we thought we were
adding a planet to the inventory of planets that we had. And then over time, it became clear that
Pluto was not a unique large object in the outer solar system, that there were actually many of
these. And as we started discovering more and more of them, we realized that the concept of
Pluto being a planet didn't make sense unless maybe we added all the rest of them as planets.
So, you know, you could have imagined actually a different direction that this could have gone,
where all the other objects that were discovered in that belt, or at least all the ones let's say
above a certain size, became planets instead of Pluto being declassified. But we were now aware
of many objects out there in the outer solar system, and what's called the Kuiper Belt that are
of the same size, or in some cases even larger than Pluto. So the declassification was really
just a realization that it was not in the same category as the other planets in the solar system,
and we basically needed to refine our definition in such a way that took into account that there's
this belt of debris out there in the outer solar system of things with a range of sizes.
Is there a hope for clear categorization of what is a planet and not? Or is it all just
gray area? When you study planets, when you study moon satellites of those planets,
is there a line that could be cleanly drawn, or is it just a giant mess? This is all like a fluid,
let's say not a mess, but it's like fluid of what is a planet, what is a moon of a planet,
what is debris, what is asteroids, all that kind of. So there are technically clear definitions
that were set down by the IAU, the International Astronomy Union. Is it size-related? Like what
are the parameters based on what? So the parameters are that it has to orbit the sun,
which was essentially to rule out satellites. Of course, this was a not very forward thinking
definition because it technically means that all extrasolar planets, according to that definition,
are not planets. So it has to orbit the sun. It has to be large enough that its gravity has
caused it to become spherical in shape, which also applies to satellites and also applies to
Pluto. The third part of the definition is the thing that really rules out everything else,
which is that it has to have cleared out its orbital path. And because Pluto orbits in a belt
of material, it doesn't satisfy that stipulation. Why didn't you clear out the path? It's not big
enough to knock everybody out of the way. And this actually is not the first time it has happened.
So Ceres, when it was discovered, Ceres is the largest asteroid in the asteroid belt,
and it was originally considered a planet when it was first discovered. And it went through exactly
the same story history where people actually realized that it was just one of many asteroids
in the asteroid belt region, and then it got declassified to an asteroid, and now it's back
to a dwarf planet. So there is a lot of reclassification. So to me, as somebody who studies
solar system objects, I just personally don't care my level of interest in something has nothing
to do with what it's classified as. So my favorite objects in the solar system are all moons,
and frequently when I talk about them, I refer to them as planets because to me, they are
planets. They have volcanoes. They have geology. They have atmospheres. They're planet-like worlds,
and so the distinction is not super meaningful to me, but it is important just for having a
general framework for understanding and talking about things to have a precise definition.
So you don't have a special romantic appreciation of a moon versus a planet versus an asteroid. It's
just an object that flies out there, and it doesn't really matter what the categorization is.
Because there's movies about asteroids and stuff, and then there's movies about the moon,
whatever, it's a really good movie. There's something about moons that's almost like an
outlier. You think of a moon as a thing that's the secret part, and the planet is the more vanilla
regular part. None of that. You don't have any of that? No, I actually do. I really, satellites are
the moons are my favorite things in the solar system, and I think part of what you're saying,
I agree from maybe a slightly different perspective, which is from the perspective of exploration.
We've spent a lot of time sending spacecraft missions to planets. We had a mission to Jupiter.
We had a mission to Saturn. We have plenty of missions to Mars and missions to Venus.
I think that exploration of the moons in the outer solar system is the next frontier of solar
system exploration. The belt of debris just real quick, that's out there. Is there something
incredible to be discovered there? Again, we tend to focus on the planets and the moons,
but it feels like there's probably a lot of stuff out there, and it probably,
what is it? It's like a garbage collector from outside of the solar system. Doesn't it protect
from other objects that kind of fly in and what, it just feels like it's a cool, you know, when
you walk along the beach and look for stuff and look for, it feels like that's that kind of place,
where you can find cool, weird things. I guess in our conversation today, when we think about
tools and what science is studying, is there something to be studied out there, or we just
don't have maybe the tools yet, or there's nothing to be found? There's absolutely a lot to be found
so the material that's out there is remnant material from the formation of our solar system.
We don't think it comes from outside the solar system, at least not most of it,
but there are so many fascinating objects out there, and I think what you fit on is exactly
right that we just don't have the tools to study them in detail, but we can look out there and we
can see there are different species of ice on their surface that tells us about, you know,
the chemical composition of the disk that formed our solar system. Some of these objects are way
brighter than they should be, meaning they have some kind of geological activity. People have
hypothesized that some of these objects have subsurface oceans. You could even stretch your
imagination and say some of those oceans could be habitable, but we can't get very detailed
information about them because they're so far away, and so I think if any of those objects were in
the inner solar system, it would be studied intently and would be very interesting.
So would you be able to design a probe in that like very dense debris field, be able to like
hop from one place to another? Is that just outside of the realm of like, how would you even design
devices or sensors that go out there and take pictures and land? Do you have to land to truly
understand a little piece of rock, or can you understand it from remotely, like fly up close
and remotely observe? You can learn quite a lot from just a flyby, and that's all we're currently
capable of doing in the outer solar system. The New Horizons mission is a recent example,
which flew by Pluto, and then they had searched for another object that was out there in the
Kuiper Belt, any object that was basically somewhere that they could deflect their trajectory to
actually fly by, and so they did fly by another object out there in the Kuiper Belt, and they
take pictures and they do what they can do. And if you've seen the images from that mission of
Pluto, you can see just how much detail we have compared to just the sort of reddish dot
that we knew of before. So you do get an amazing amount of information actually from just essentially
a high speed flyby. It always makes me sad to think about flybys that we might be able to,
we might fly by a piece of rock, take a picture, and think, oh, that looks pretty and cool and
whatever, and that you could study certain like composition of the surface and so on.
But it's actually teeming with life, and we won't be able to see it at first. And it's sad,
because you know, like when you're on a deserted island, you wave your hands and the
thing flies by and you're trying to get their attention, and they probably do the same, well,
in their own way, bacteria probably, right? And we miss it. I don't know,
some reason it makes me, it's the FOMO, it's fear of missing out. It makes me sad that there might
be life out there. And we don't, we're not in touch with it. We're not talking. Yeah. Well, okay.
A sad pause, a Russian philosophical pause. Okay. What are the tools available to us to
study planets and their moons? Oh my goodness, that is such a big question. So among the field
of astronomy, so planetary science broadly speaking, well, it falls kind of at the border of astronomy,
geology, climate science, chemistry, and even biology. So it's kind of on the border of many
things, but part of it falls under the heading of astronomy. And among the things that you can study
with telescopes like Solar System Moons and planets, the Solar System is really unique in
that we can actually send spacecraft missions to the objects and study them in detail. And so I
think that's the kind of type of tool that people are most aware of, this most popularized, these
amazing NASA missions that either you fly by the object, you orbit the object, you land on the
object, potentially you can talk about digging into it, drilling, trying to detect tectonic
tremors on its surface. The types of tools that I use are primarily telescopes. And so my background
is in astrophysics. And so I actually got into Solar System science from astronomy, not from,
you know, a childhood fascination with spacecraft missions, which is actually what
a lot of planetary scientists became planetary scientists because of childhood fascination
with spacecraft missions, which is kind of interesting for me to talk to people and see
that trajectory. I kind of came at it from the fascination with telescopes angle.
All right. So you like telescopes, not rockets, or at least the Earth?
When I was a kid, it was looking at the stars and playing with telescopes that really fascinated
me, and that's how I got into this. But telescopes, it's amazing how much detail and how much
information you can get from telescopes today. You can resolve individual cloud features and
watch them kind of shear out in the atmosphere of Titan. You can literally watch volcanoes on
Io change from day to day as the lava flows expand. So, and then, you know, with spectroscopy,
you get compositional information on all these things. And it's when I started doing Solar
System Astronomy, I was surprised by how much detail and how much information you can get
even from Earth, and then as well as from orbit, like the Hubble Space Telescope or the James Webb.
So with the telescope, you can, I mean, how much information can you get about volcanoes,
about storms, about sort of weather, just so we kind of get a sense like what a resolution we're
talking about? Well, in terms of resolution, so to, you know, on a given night, if I go and take
a picture of Io and it's volcanoes, you can sometimes see at least a dozen different volcanoes.
You can see the infrared emission coming off of them and resolve them, separate them from one
another on the surface, and actually watch how the heat coming off of them changes with time.
And I think this time variability aspect is one of the big advantages we get from telescopes.
So you send a spacecraft mission there and you get an incredible amount of information over a
very short time period. But for some science questions, you need to observe something for
30 years, 40 years, like let's say you want to look at the Moon Titan, which has one of the most
interesting atmospheres in the Solar System. Its orbital period is 29, 30 years. And so if you
want to look at how its atmospheric seasons work, you have to observe it over that long of a time
period. And you're not going to do that with a spacecraft, but you can do it with telescopes.
Can we just zoom in on certain things like, let's talk about Io, which is the Moon of Jupiter.
Okay, it's like epic. There's like volcanoes all over the place. From a distance, it's awesome.
So can you tell me about this Moon and you're sort of a scholar of many planets and moons,
but that one kind of stood out to me. So why is that an interesting one?
For so many reasons, but Io is the most volcanically active object in the Solar System.
It has hundreds of active volcanoes on it. It has volcanic plumes that go hundreds of kilometers
up above its surface. It puts out more volume of magma per volcano than volcanoes on Earth today.
Okay. But I think to me, the reason that it's most interesting is as a laboratory for understanding
planetary processes. So one of the broad goals of planetary science is to put together a sort of
more general and coherent framework for how planets work in general. Our current framework,
you know, it started out very Earth centric. We start to understand how Earth volcanoes work.
But then when you try to transport that to somewhere like Io that doesn't have an atmosphere,
which makes it has a very tenuous atmosphere, which makes a big difference for how the magma
digases. For something that's really small, for something that has a different heat source,
for something that's embedded in another object's magnetic field, the kind of intuition we have
from Earth doesn't apply. And so broadly, planetary science is trying to broaden that
framework so that you have a kind of narrative that all you can understand how each planet
became different from every other planet. And I'm already making a mistake. When I say planet,
I mean planets and moons, like I said, I see the moons as planets.
Yeah. I actually already noticed that you didn't introduce Io as the moon of Jupiter.
You completely, you kind of ignored the fact that Jupiter exists. It's like, let's focus on this.
Yeah. Okay. So, Anne, you also didn't mention Europa, which I think is the,
is that the most famous moon of Jupiter? Is that the one that gets attention because it might have
life? Exactly. Yeah. But to you, Io is also beautiful. What's the difference between volcanoes
on Io versus Earth? You said atmosphere makes a difference. What? Yeah. The heat source plays
a big role. So, many of the moons in the outer solar system are heated from gravitationally by
tidal heating. And I'm happy to describe what that is. Yeah, please. What's tidal? Yes.
So, tidal heating is, it's, if you want to understand and contextualize planets and moons,
you have to understand their heat sources. So, for Earth, we have radioactive decay in our
interior as well as residual heat of formation. But for satellites, tidal heating plays a really
significant role and in particular in driving geological activity on satellites and potentially
making those subsurface oceans in places like Europa and Enceladus habitable. And so, the way
that that works is if you have multiple moons and their orbital periods are integer multiples of one
another, that means that they're always encountering each other at the same point in the orbit. So,
if they were on just random orbits, they'd be encountering each other at random places and
the gravitational effect between the two moons would be canceling out over time. But because
they're always meeting each other at the same point in the orbit, those gravitational interactions
add up coherently. And so, that tweaks them into eccentric orbits. What's an eccentric orbit?
So, eccentric orbit or elliptical orbit, it just means non-circular. So, a deviation from a circular
orbit and that means that for Io or Europa, at some points in their orbit, they're closer to
Jupiter and at some points in the orbit, they're farther away. And so, when they're closer, they're
stretched out in a sense, but literally just not very stretched out, like a couple hundred meters,
something like that. And then when they're farthest away, they're less stretched out. And so, you
actually have the shape of the object deforming over the course of the orbit. And these orbits
are like just a couple of days. And so, in the case of Io, that is literally sufficient friction
in its mantle to melt the rock of its mantle. And that's what generates the magma.
That's the source of the magma. Okay. So, Europa is, I thought there was like ice and
oceans underneath kind of thing. So, why is Europa not getting a friction?
It is. It's just a little bit farther away from Jupiter. And then, Ganymede is also in the orbital
resonance. So, it's a three-object orbital resonance in the Jupiter system. But we have these sorts
of orbital resonances all over the solar system and also in exoplanets. So, for Europa, basically,
because it's farther from Jupiter, the effect is not as extreme, but you do still have heat
generated in its interior in this way. And that may be driving, could be driving hydrothermal
activity at the base of its ocean, which obviously would be a really valuable thing for life.
Cool. So, it's like heating up the ocean a little bit.
Heating up the ocean a little bit and specifically in these hydrothermal vents where we see really
interesting life evolve in the bottom of Earth's oceans.
That's cool. Okay. So, what's Io? What else? So, we know the source is this friction,
but there's no atmosphere. I'm trying to get a sense of what it's like if you and I were to visit
Io. What would that look like? What would it feel like? Is this the entire thing covered in basically
volcanoes? So, it's interesting because there's very little atmosphere. The surface is actually
really cold, very far below freezing on the surface when you're away from a volcano. But the
volcanoes themselves are over a thousand degrees, or the magma when it comes out is over a thousand
degrees. But it does come to the surface of the magma? It does, yep. In particular places,
whoa, that probably looks beautiful. So, it's frozen, not ice. What is rock? It's a really
cold rock. And then you just have this, what would that look like with no atmosphere? Would it be
smoke? What does it look like? Is it just magma, like just red, yellow, like liquidy things?
It's black. It's black and red, I guess. Like think of the type of magma that you see in Hawaii.
So, different types of magma flow in different ways, for example. So, in somewhere like Io,
the magma is really hot. And so, it will flow out in sheets because it has really low viscosity.
And I think the lava flows that we've been having in Hawaii over the past couple years
are probably a decent analogy, although Io's magmas, lavas are even more fluid and faster
moving. Oh, faster. Like what, how fast, like if you, by the way, started through the telescope,
are you tracking at what time scale? Like every frame is how far apart, if you're looking through
the telescope. Are we talking about seconds or we're talking about days, months? When you kind
of track, try to get a picture of what the surface might look like, what's the frequency?
So, it depends a little bit on what you want to do. Ideally every night,
but you could take a frame every second and see how things are changing. The problem with that
is that for things to change on a one second time scale, you actually see something change
that fast, you have to have super high resolution. The spatial resolution we have is a couple hundred
kilometers. And so, things are not changing on those scales over one second unless you have
something really crazy happening. So, if you get, if you get a telescope closer to Io, if you get,
or a camera closer to Io, would you be able to understand something? Is that something of interest
to you? Would you be able to understand something deeper about these volcanic eruptions and how
magma flows and just the rate of the magmas? Or is it basically enough to have the kilometer
resolution? Do you get a sense? No way. We want to go there. Absolutely. You want to go to Io?
I mean, I don't want to go there personally, but I want to send a spacecraft mission there,
absolutely. Why? Why are you scared? Why am I scared? Oh, you mean you don't? I don't want to go
there as a human. As a human. I want to send a robot there to look at it. This is again,
everybody's discriminating against robots. This is not, but it's fine. But it's not
hospitable to humans in any way, right? Just very cold and very hot. It's very cold. The
atmosphere is composed of sulfur dioxide, so you can breathe it. There's no pressure. I mean,
it's kind of all the same things you talk about. One talks about Mars only worse. The atmosphere
is still a thousand times less dense than Mars's. The radiation environment is terrible because
you're embedded deep within Jupiter's magnetic field. Jupiter's magnetic field is full of charged
particles that have all come out of Io's volcanoes, actually. Jupiter's magnetic field strips all this
material out of Io's atmosphere. That populates its entire magnetosphere, and then that material
comes back around and hits Io and spreads throughout the system, actually. It's like
Io is the massive polluter of the Jupiter system. Okay, cool. So what is studying Io teach you about
volcanoes on Earth or vice versa? Is in the difference of the two, what insights can you
mine out that might be interesting in some way? Yeah, we try to port the tools that we
use to study Earth volcanism to Io, and it works to some extent, but it is challenging
because the situations are so different. The compositions are really different when you talk
about outgassing. Earth volcanoes outgast primarily water and carbon dioxide, and then
sulfur dioxide is the third most abundant gas. And on Io, the water and carbon dioxide are
not there. Either it didn't form with them or it lost them, we don't know. And so the chemistry
of how the magma outgases is completely different. But the kind of one, to me, most interesting
analogy to Earth is that, so Io, as I've said, it has these really low viscosity magmas. The
lava spreads really quickly across its surface. It can put out massive volumes of magma in
relatively short periods of time. And that sort of volcanism is not happening anywhere else in
the solar system today. But literally, every terrestrial planet and the moon had this, what
we call, very effusive volcanism early in their history. Okay, so this is almost like a little
glimpse into the early history of Earth. Yeah. Okay, cool. So what are the chances that a volcano
on Earth destroys all of human civilization? Maybe I wanted to sneak in that question. Yeah, a
volcano on Earth. Do you think about that kind of stuff when you just study volcanoes elsewhere?
Because then it's kind of humbling to see something so powerful and so hot,
like so unpleasant for humans. And then you realize we're sitting on many of them here.
Right. Yeah, Yellowstone as a classic example. I don't know what the chances are of that happening.
My intuition would be that the chances of that are lower than the chances of us getting wiped out
by some other means that in the time, you know, that maybe it'll happen eventually,
that there'll be one of these massive volcanoes on Earth, but we'll probably be gone by then
by some other means, not to sound bleak. That's very comforting. Okay, so can we talk about Europa?
Is there, so maybe can you talk about the intuition, the hope that people have about
life being on Europa? Maybe also, what are the things we know about it? What are the things
to you that are interesting about that particular moon of Jupiter? Sure. Yeah, Europa is, from many
perspectives, one of the really interesting places in the solar system among the solar system moons.
So there are a few, there has, there's a lot of interest in looking for or understanding
the potential for life to evolve in the subsurface oceans. I think it's fairly widely accepted that
the chances of life evolving on the surfaces of really anything in the solar system is very low.
The radiation environment is too harsh. And there's, there's just not liquids on the surface of
most of these things. And it's canonically accepted that liquids are required for life. And so the
subsurface oceans, in addition to maybe Titan's atmosphere, the subsurface oceans of the icy
satellites are one of the most plausible places in the solar system for life to evolve. Europa
and Celadus are interesting because for many of the big satellites, so Ganymede and Callisto,
also satellites of Jupiter, also are thought to have subsurface oceans. But they are, so they have
these ice shells, and then there's an ocean underneath the ice shell. But on those moons
around Ganymede, we think that there's another ice shell underneath, and then there's rock.
And the reason that that is a problem for life is that your ocean is probably just pure water because
it's trapped between two big shells of ice. So Europa doesn't have this ice shell at the bottom
of the ocean, we think. And so the water and rock are in direct interaction. And so that means that
you can basically dissolve a lot of material out of the rock. You potentially have this hydrothermal
activity that's injecting energy and nutrients for life to survive. And so this rock water interface
is considered really important for the potential habitability.
As a small aside, you kind of said that it's canonically assumed that
water is required for life. Is it possible to have life in the volcano? I remember people were
like a National Geographic program or something kind of hypothesizing that you can really have
life anywhere. So as long as there's a source of heat, a source of energy, do you think it's
possible to have life in a volcano, like no water? I think anything's possible. I think it's so
water, it doesn't have to be water. You can tell as you identified, I phrased that really
carefully. It's canonically accepted that because scientists recognize that we have no idea what
broad range of life could be out there. And all we really have is our biases of life as we know it.
But for life as we know it, it's very helpful to have or even necessary to have some kind of
liquid and preferably a polar solvent that can actually dissolve molecules, something like water.
So the case of liquid methane on Titan is less ideal from that perspective. But liquid magma,
if it stays liquid long enough for life to evolve, you have a heat source, you have a liquid,
you have nutrients. In theory, that checks your three classic astrobiology boxes.
That'd be fascinating. It'd be fascinating if it's possible to detect it easily. How would we
detect if there is life on Europa? Is it possible to do in a non-contact way from a distance through
telescopes and so on? Or do we need to send robots and do some drilling?
I think realistically, you need to do the drilling. So Europa also has these long tectonic
features on its surface where it's thought that there's potential for water from the ocean to
be somehow making its way up onto the surface. And you could imagine some out there scenario
where there's bacteria in the ocean. It's somehow working its way up through the ice shell. It's
spilling out on the surface. It's being killed by the radiation. But your instrument could detect
some spectroscopic signature of that dead bacterium. But that's many ifs and assumptions.
That's a hope because then you don't have to do that much drilling. You can collect from the surface.
Right. Or even I'm thinking even remotely.
Oh, remotely. Yeah. That's sad that there's a single cell civilization living underneath all
that ice trying to get up. Trying to get out. So Enceladus gives you a slightly better chance
of that because Enceladus is a moon of Saturn and it's broadly similar to Europa in some ways.
It's an icy satellite. It has a subsurface ocean that's probably in touch with the rocky interior.
But it has these massive geysers at its south pole where it's spewing out material that appears to
be originating all the way from the ocean. And so in that case, you could potentially fly through
that plume and scoop up that material and hope that at the velocities you'd be scooping it up,
you're not destroying any signature of the life you're looking for. But let's say that
you have some ingenuity and can come up with a way to do that. It potentially gives you
a more direct opportunity at least to try to measure those bacteria directly.
Can you tell me a little more on how do you pronounce it? Celas?
Enceladus.
Enceladus? Can you tell me a little bit more about Enceladus? We've been talking way too much about
Jupiter. Saturn doesn't get enough love. Not enough. Saturn doesn't get as much love. So what's
Enceladus? Is that the most exciting moon of Saturn?
Depends on your perspective. It's very exciting from an astrobiology perspective.
I think Enceladus and Titan are the two most unique and interesting moons of Saturn that
definitely both get the most attention also from the life perspective.
So what's more likely Titan or Enceladus for life?
If you were to bet all your money in terms of like investing,
which to investigate, what are the difference between the two that are interesting to you?
Yeah. So the potential for life in each of those two places is very different. So Titan is the
one place in the solar system where you might imagine, again, all of this is so speculative,
but you might imagine life evolving in the atmosphere. So from a biology perspective,
Titan is interesting because it forms complex organic molecules in its atmosphere.
It has a dense atmosphere. It's actually denser than Earth's. It's the only moon that has
an atmosphere denser than Earth's. And it's got tons of methane in it. What happens is that
methane gets irradiated, it breaks up, and it reforms with other things in the atmosphere.
It makes these complex organic molecules and it's effectively doing prebiotic chemistry in
the atmosphere. While it's still freezing cold. Yes. Okay. What would that be like?
Would that be pleasant for humans to hang out there? Is this really cold?
There's nowhere in the solar system that would be pleasant for humans. It would be cold. You
couldn't breathe the air. Recolonization wise, if there's an atmosphere, isn't that a big plus?
Or still a ton of radiation? Okay. So Titan, that's a really nice feature that
the life could be in the atmosphere because then it might be remotely observable or certainly
is more accessible if you visit. Okay. So what about Enceladus? So that would be still in the
ocean. Right. And Enceladus has the advantage, like I said, of spewing material out of its
south pole so you could collect it. But it has the disadvantage of the fact that we don't actually
really understand how its ocean could stay globally liquid over the age of the solar system.
And so there are some models that say that it's going through this cyclical evolution
where the ocean freezes completely and thaws completely and the orbit sort of
oscillates in and out of these eccentricities. And in that case, the potential for life ever
occurring there in the first place is a lot lower because if you only have an ocean for 100
million years, is that enough time? And it also means that might be mass extinction events if
it does occur. Right. And it just freezes. Yes. Again, very sad, man. This is very depressing.
All that slaughter of life elsewhere. How unlikely do you think life is on Earth?
So when you look, when you study other planets and you study the contents of other planets,
does that give you a perspective on the origin of life on Earth, which again is full of mystery
in itself, not the evolution, but the origin, the first springing to life,
like from nothing to life, from the basic ingredients to life?
I guess another way of asking it is how unique are we?
Yeah, it's a great question. And it's one that just scientifically we don't have an answer to.
We don't even know how many times life evolved on Earth if it was only once or if it happened
independently a thousand times in different places. We don't know whether it's happened
anywhere else in the universe, although it feels absurd to believe that we are
the only life that evolves in the entire universe, but it's conceivable. We just have
no real information. We don't understand really how life came about in the first place on Earth.
I mean, so if you look at the Drake equation that tries to estimate how many
alien civilizations are out there, planets have a big part to play in that equation.
If you were to bet money in terms of the odds of origins of life on Earth,
I mean, this all has to do with how special and unique is Earth.
What you land in terms of the number of civilizations has to do with
how unique their rare Earth hypothesis is, how rare a special is Earth,
how rare and special is the solar system? If you had to bet all your money on a completely
unscientific question, well, no, it's actually rigorously scientific. We just don't know a lot
of things in that equation. There's a lot of mysteries about that. It's slowly becoming
better and better understood in terms of exoplanets, in terms of how many solar systems are out
there, where there's planets, there are Earth-like planets that's getting better and better understood.
What's your sense from that perspective, how many alien civilizations are out there?
Zero or one plus? You're right that the equation is being better understood,
but you're really only talking about the first three parameters in the equation or something.
You know, how many stars are there? How many planets per star? Then we're just barely scratching
the surface of what fraction of those planets might be habitable. The rest of the terms in the
equation are like, how likely is life to evolve given habitable conditions? How likely is it to
survive all these things? They're all these huge unknowns. Actually, I remember when I first
saw that equation, I think it was my first year of college, and I thought, this is ridiculous.
This is a common sense that didn't need to give a name and b, just a bunch of unknowns. It's like
putting our ignorance together in one equation. Now I understand this equation, it's not
something we'll ever necessarily have the answer to. It just gives us a framework for having
the exact conversation we're having right now. And I think that's how it was intended in the
first place when it was put into writing, was to give people a language to communicate about
the factors that go into the potential for aliens to be out there and for us to find them.
I would put money on there being aliens. I would not put money on us having definitive
evidence of them in my lifetime. Well, definitive is a funny word because my sense is,
this is the saddest part for me, is my sense in terms of intelligent alien civilizations.
I feel like we're so self-obsessed that we literally would not be able to detect them
even when they're in front of us. Trees could be aliens, but their intelligence could be
realized on a scale, on a time scale or physical scale that we're not appreciating.
Trees could be way more intelligent than us. I don't know. This is just a dumb example.
It could be rocks or it could be things like, I love this, this is Dawkins memes.
It could be the ideas we have. Where do ideas come from? Where do thoughts come from?
Maybe thoughts are the aliens or maybe thoughts is the actual mechanisms of communication
in physics. We think of thoughts as something that springs up from neurons firing. Where the
hell do they come from? And now, what about consciousness? Maybe consciousness is the
communication. It sounds like ridiculous, but we're so self-centered on this space-time
communication in physical space using written language, spoken with audio,
on a time scale that's very specific, on a physical scale that's very specific.
So I tend to think that bacteria will probably recognize, like moving organisms will probably
recognize, but when that forms itself into intelligence, most likely it'll be robots of
some kind, because we won't be meeting the origins. We'll be meeting the creations of those
intelligences. We just would not be able to appreciate it. And that's the saddest thing to me,
that we're too dumb to see aliens. We kind of think like, look at the progress of science.
We've accomplished so much. The sad thing, it could be that we're just like in the first 0.0001%
of understanding anything. It's humbling. I hope that's true, because I feel like we're very ignorant
as a species. And I hope that our current level of knowledge only represents the 0.001% of what
we will someday achieve. That actually feels optimistic to me. Well, I feel like that's easier
for us to comprehend in the space of biology, and not as easy to comprehend in the space of physics,
for example, because we have a sense that we have, if you talk to theoretical physicists,
they have a sense that we understand the basic laws that form the nature of reality,
of our universe. So there's much more, like physicists, they're much more confident.
Biologists are like, this is a squishy mess, we're doing our best. But I would be,
it'd be fascinating to see if physicists themselves would also be humbled by their being,
like what the hell is dark matter and dark energy? What the hell is the, not just the origin of the,
not just the Big Bang, but everything that happens since the Big Bang. A lot of things that
happen since the Big Bang, we have no ideas about it, except basic models of physics.
Right. Or what happened before the Big Bang?
Yeah, yeah, what happened before, or what's happening inside the black hole?
Why is there a black hole at the side of our galaxy? Can somebody answer this? A super massive
black hole? Nobody knows how it started. And they seem to be like in the middle of all galaxies.
So that could be a portal for aliens to communicate through consciousness. Okay.
All right, back to planets. What's your favorite outside of Earth? What's your favorite planet or
moon? Maybe outside of the ones, well first, have we talked about it already? Or, and then
if we did mention it, what's the one outside of that?
Oh gosh, and to come up with another favorite that's not Io?
Oh, Io is the favorite.
Oh, absolutely.
Why is Io the favorite?
I mean, basically everything I've already said, it's just such an amazing and unique
object. But on, I guess, a personal note, it's probably the object that made me become
a planetary scientist. It's the first thing in the solar system that really deeply captured my
interest. And when I started my PhD, I wanted to be an astrophysicist working on things like
galaxy evolution. And sort of slowly, I had done some projects in the solar system, but Io was
the thing that like really caught me into doing solar system science.
Okay, let's, let's leave moons aside. What's your favorite planet? It sounds like you like moons
better than planets. So let's, that's accurate. But the planets are, are fascinating. I think,
you know, I find that the planets in the solar system really fascinating. What I like about
the moons is that they, there's so much less that is known. There's still a lot more discovery
space and the questions that we can ask are still the bigger questions.
Gotcha.
Which, you know, I, and maybe I'm being unfair to the planets because we're still trying to
understand things like was there ever life on Mars? And that is a huge question and one that
we've sent numerous robots to Mars to try to answer. So maybe I'm being unfair to the planets,
but there is certainly quite a bit more information that we have about the planets than the moons.
But I mean, Venus is, is a fascinating object. So I like the objects that lie at the extremes.
I think that if we can make a sort of theory or, or like I've been saying, framework for
understanding planets and moons that can incorporate even the most extreme ones, then,
you know, those are the things that really test your theory and test your understanding. And so
they've always really fascinated me, not so much the nice habitable places like Earth, but
these extreme places like Venus that have sulfuric acid clouds and just incredibly hot and dense
surfaces. And Venus, of course, I love volcanism for some reason. And Venus has,
probably has volcanic activity, definitely has in their recent past, maybe has ongoing today.
What do you make of the news? Maybe you can update it in terms of life being discovered
in the atmosphere of Venus? Is that sorry? Okay. You have opinion, I can already tell you
have opinions. Was that fake news? I got excited. I saw that. What's the, what's the final,
is there a life on Venus? So the detection that was reported was the detection of the
molecule phosphine. And they said that they tried every other mechanism they could think of to produce
phosphine. And they none of no mechanism worked. And then they said, well, we know that life
produces phosphine. And so that was sort of the train of logic. And I don't personally believe
that phosphine was detected in the first place. Okay. So then, I mean, this is just one study,
but I as a layman, I'm skeptical a little bit about tools that sense the contents of an atmosphere,
like contents of an atmosphere from remotely and making conclusive statements about life.
Oh, yeah. Well, that connection that you just made, the contents of the atmosphere to the life
is, is a tricky one. And yeah, I know that that claim received a lot of criticism for the lines
of logic that went from detection to to claim of life. Even the detection itself, though,
doesn't meet the sort of historical scientific standards of a detection. It was a very tenuous
detection and only one line of the species was detected. And a lot of really complicated data
analysis methods had to be applied to even make that weak detection. Yeah. So it could be, it
could be noise, it could be polluted data, it could be all all those things. And so it doesn't
have, it doesn't meet the, the level of rigor that you would hope. But of course, I mean,
we're doing our best. And it's clear that the human species are hopeful to find life.
Clearly. Yes. Everyone is so excited about that possibility.
All right. Let's, let me ask you about Mars. So
there's a guy named Elon Musk. And he seems to want to take something called Dogecoin there.
First to the moon. I'm just, I'm just kidding about the Dogecoin. I, I even know what the,
what the heck is up with that whole, I think, I think humor has power in the 21st century
in a way to spread ideas in the most positive way. So I love that kind of humor because it makes
people smile, but it also kind of sneaks, it's like a Trojan horse for cool ideas.
You, you open with humor and you, like the humor is the appetizer. And then the main
meal is the science and the engineering. Anyway, do you think it's possible to colonize Mars
or other planets in the solar system? But we're especially looking to Mars. Is there
something about planets that make them very harsh to humans? Is there something in particular you
think about? And maybe in a high, like big picture perspective, do you have a whole week,
we do in fact become a multi-planetary species?
I do think that if our species survives long enough and we don't wipe ourselves out or get
wiped out by some other means that we will eventually be able to colonize other planets.
I do not expect that to happen in my lifetime. I mean, tourists may go to Mars, tourists,
people who commit years of their life to go into Mars as a tourist may go to Mars.
I don't think that we will colonize it. Is there a sense why it's just too harsh
from an environment to, to, to, to, like it's too costly to build something habitable there
for a large population? I think that we need to do a lot of work and learning how to use the
resources that are on the planet already to do the things we need. So if you're talking about
someone going there for a few months, so we'll back up a little bit. There are many things that
make Mars not hospitable, temperature, you can't breathe air, you need a pressure suit,
even if you're on the surface, the radiation environment is, you know, even in all of those
things, the radiation environment is too harsh for the human body. All of those things seem
like they could eventually have technological solutions. The challenge, the real significant
challenge to me seems to be the, the creation of a self-sustaining civilization there, you know,
you can bring pressure suits, you can bring oxygen to breathe, but those are all in limited supply.
And if we're going to colonize it, we need to find ways to make use of the resources that are
there to do things like produce food, produce the air that humans need to keep breathing,
just in order to make it self-sustaining, there's a tremendous amount of work that has to be done.
And people are working on these problems, but I think that's going to be a major obstacle in
going from visiting where we can bring everything we need to survive in the short term to actually
colonizing. Yeah, I find that whole project of the human species quite inspiring, these like huge
moonshot projects. Somebody, I was reading something in terms of the source of food that's
that may be the most effective on Mars is you could farm insects. That's the easiest thing to farm.
So we'd be eating like cockroaches before living on Mars, because that's the easiest thing to actually
as a source of protein. So growing a source of protein is the easiest thing is insects. I just
imagine this giant for people who are afraid of insects. This is not a pleasant. Maybe you're not
supposed to even think of it that way. It'll be like a cockroach milkshake or something like that.
Right. I wonder if have people been working on the genetic engineering of insects to make them
radiation friendly or pressure resistant or whatever. What can possibly go wrong?
What can cockroaches make in radiation resistant? They're already like survived everything. Plus,
I took an allergy test in Austin. So there's everybody's alert is like the allergy levels
are super high there. And one of the things apparently, I'm not allergic to any insects
except cockroaches. It's hilarious. So maybe, well, I'm going to use that as you know,
people use an excuse that I'm allergic to cats to not have cats. I'm going to use that as an
excuse to not go to Mars as one of the first batch of people. I was going to ask if you had
the opportunity when you go. Yeah, I'm joking about the cockroach thing. I would definitely go.
I love challenges. I love things. I love doing things where the possibility of death
is not insignificant because it makes me appreciate it more. Meditating on death
makes me appreciate life. And when the meditation on death is forced on you because of how difficult
the task is, I enjoy those kinds of things. Most people don't, it seems like. But I love the idea
of difficult journeys for no purpose whatsoever, except exploration, going into the unknown,
seeing what the limits of the human mind and the human body are. It's like, what the hell
else is this whole journey that we're on for? But it could be because I grew up in the Soviet Union,
there's a kind of love for space, like the space race, the Cold War created. I don't know if still,
it permeates American culture as much, but especially with the data as a scientist,
I think I've loved the idea of humans striving out towards the stars, always. From the engineer
perspective, it's been really exciting. I don't know if people love that as much in America
anymore. I think Elon is bringing that back a little bit, that excitement about rockets and
going out there. So that's hopeful. But for me, I always love that idea. From an alien scientist
perspective, if you were to look back on Earth, is there something interesting you could say
about Earth? Like, how would you summarize Earth? Like, you know, like Hitchhiker's Guide to the
Galaxy? Like, if you had to report, like, write a paper on Earth, or like a letter, like a one
pager summarizing the contents of the surface and the atmosphere, is there something interesting?
Like, do you ever take that kind of perspective on it? I know you like volcanism, so volcanoes,
that'll probably be in the report. I was going to say, that's where I was going to go first.
There are a few things to say about the atmosphere, but in terms of the volcanoes, so one of the
really interesting puzzles to me in planetary sciences, so we can look out there, and we've
been talking about surfaces and volcanoes and atmospheres and things like that. But that is
just, you know, this tiny little veneer on the outside of the planet, and most of the planet is
completely sort of inaccessible to telescopes or to spacecraft missions. You can drill a meter
into the surface, but you know, that's still really the veneer. And one of the cool puzzles
is looking at what's going on on the surface and trying to figure out what's happening underneath,
or just any kind of indirect means that you have to study the interior, because you can't
dig into it directly, even on Earth, you can't dig deep into Earth. So from that perspective,
looking at Earth, one thing that you would be able to tell from orbit, given enough time,
is that Earth has tectonic plates. So you would see that volcanoes follow the edges.
If you trace where all the volcanoes are on Earth, they follow these lines that trace the
edges of the plates. And similarly, you would see things like the Hawaiian string of volcanoes that
you could infer, just like, you know, we did as people actually living on Earth, that the plates
are moving over some plume that's coming up through the mantle. And so you could use that to say, if
the aliens could look at where the volcanoes are happening on Earth and say something about
the fact that Earth has plate tectonics, which makes it really unique in the solar system.
So the other planets don't have plate tectonics? It's the only one that has plate tectonics.
Yeah. Well, what about Io and the friction and all that? That's not plate tectonics. What's the
difference between, oh, is plate tectonics like another layer of solid rock that moves around
and there's cracks? Exactly. Yeah. So Earth has plates of solid rock sitting on top of a partially
molten layer. And those plates are kind of shifting around. On Io, it doesn't have that. And the
volcanism is what we call heat pipe volcanism. It's the magma just punches a hole through the
crust and comes out on the surface. I mean, that's a simplification, but that's effectively what's
happening through the freezing cold crust. Yes. Very cold, very rigid crust. Yeah.
How does that look like, by the way? I don't think we've mentioned. So the gas that's expelled,
like if we were to look at it, is it like beautiful? Is it like boring? The gas?
Like the whole thing, like the magma punching through the IC. Yes, I'm sure it would be beautiful.
And the pictures we've seen of it are beautiful. So the magma will come out of the lava, will come
out of these fissures, and you have these curtains of lava that are maybe even a kilometer high.
So if you looked at videos, I don't know how many volcano videos you've looked at on Earth,
but you sometimes see a tiny, tiny version of this in Iceland. You see just these sheets of
magma coming out of a fissure when you have this really low viscosity magma sort of water-like
coming out at these sheets. And the plumes that come out, because there's no atmosphere,
all the plume molecules are just plume particles. Where they end up is just a function of the
direction that they left the vent. So they're all following ballistic trajectories.
And you end up with these umbrella plumes. You don't get these sort of complicated plumes that
you have on Earth that are occurring because of how that material is interacting with the
atmosphere that's there. You just have these huge umbrellas. And it's been hypothesized actually
that the atmosphere is made of sulfur dioxide and that you could have these kind of ash particles
from the volcano and the sulfur dioxide would condense onto these particles and you'd have
sulfur dioxide snow coming out of these volcanic plumes. And that's not much light though, right?
So you wouldn't be able to, like it would not make a good Instagram photo because you have to,
would you see the snow? Sure. There's light. It depends. Okay. So you could, okay. Depends what
angle you're looking at it, where the sun is, all the things like that. You know, the sunlight is
much weaker, but it's still there. It's still there. And how big is Io in terms of gravity?
Is it smaller? Is it a pretty small moon? It's quite a bit smaller than Earth anyway.
It's smaller than Earth. Okay. Okay, cool. So they float up for a little bit. So the floats,
wow, they, yeah, no, you're right. That would be, that would be, that would be gorgeous.
What else about Earth is interesting besides volcanic, so plate tectonics, I didn't realize
that that was the unique element of a planet in the solar system. Because that, I wonder what,
I mean, we experienced as human beings, it's quite painful because of earthquakes and all those
kinds of things, but I wonder if there's nice features to it. Yeah. So coming back to habitability
again, things like tectonics and plate tectonics are thought to play an important role in the
surface being habitable. And that's because you have a way of recycling materials. So
if you have a stagnant surface, everything, you know, you use up all the free oxygen,
everything reacts until you no longer have reactants that life can extract energy from.
And so if nothing's changing on your surface, you kind of reach this stagnation point.
But something like plate tectonics recycles material, you bring up new fresh material from
the interior, you bring down material that's up on the surface, and that can kind of refresh your
nutrient supply in a sense, or the sort of raw materials that the surface has to work with.
So from a kind of astrobiologist perspective, looking at earth, you would see that recycling
of material because the plate tectonics, you would also see how much oxygen is an earth
atmosphere. And between those two things, you would identify earth as a reasonable candidate
for a habitable environment, in addition to, of course, the, you know, pleasant temperature
and liquid water. But the abundance of oxygen and the the plate tectonics both play a role as well.
And also see like tiny dots, satellites flying around.
I wonder if they would be able to, I really think about that, like if they, if aliens were to visit,
and would they really see humans as the thing they should be focusing on?
I think it would take a while, right? Because it's so obvious that that should, because there's like
so much incredible, in terms of biomass, humans are a tiny, tiny, tiny fraction. There's like ants.
They would probably detect ants, right? Or they probably would focus on the water and the fish.
Because there's like a lot of what, I was surprised to learn that there's more species
on land than there is in the sea. Like there's 90, I think 90 to 95% of the species are on land.
Or on land or not in the sea. Not in the sea. I thought like there's so much going on in the
sea. But no, the, the variety that like the branch is created by evolution, apparently,
it's probably a good answer from an evolutionary biology perspective, why land created so much
diversity, but it did. So like the sea, there's so much not known about the sea, about the oceans.
But it's not, it's not diversity friendly. What can I say? It needs to, it needs to improve
its diversity. Do you think the aliens would come? I mean, the first thing they would see is, I suppose,
are cities, assuming that they had some idea of what a natural world looked like, they would see
cities and say, these don't belong. Which of these many species created these?
Yeah, I mean, there's, I, if I were to guess, it would, it's a good question. I don't know if you
do this when you look at the telescope, whether you look at geometric shapes, like if it's,
because to me, like hard corners, like what do we think is engineered?
Things that are like have kind of straight lines and corners and so on, they will probably
detect those in terms of buildings will stand out to them because that's, that goes against the basic
natural physics of the world. But I don't know if the electricity and lights and so on, it could be,
I honestly, it could be the plate tectonics. It could be like, that they're like the volcanoes,
that'd be, okay, that's the source of heat. And then they would focus, they might literally,
I mean, depending on how alien lifeforms are, they might notice the microorganisms
before they notice the big, like notice the and before the elephant. Because like,
there's a lot more of them, depending what they're measuring device, we think like size matters,
but maybe with their tools of measurement, they would look for quantity versus size,
like why focus on the big thing, focus on the thing that there's a lot of,
and when they see humans, depending on their measurement devices, they might see,
we're made up of billions of organisms. Like the fact that we have, we're very human-centered,
we think we're one organism, but that may not be the case. They might see, in fact,
they might also see like a human city as one organism. Like, what is this thing that like,
clearly this organism gets aroused at night, because the lights go on. And then,
and then it like, it sleeps during the day. I don't know, like the what perspective you take
on the city. Is there something interesting about earth or other planets in terms of weather
patterns? So we talked a lot about volcanic patterns. Is there something else about weather
that's interesting, like storms or variations in temperature, all those kinds of things?
Yeah, so there's sort of every planet and moon has the kind of interesting and unique
weather pattern. And those weather patterns are really, we don't have a good understanding of
them. We don't even have a good understanding of the global circulation patterns of many of these
atmospheres, why the storm systems occur. So the composition and occurrence of storms and clouds
and these objects is another one of these kind of windows into the interior that I was talking
about with surfaces, one of these ways that we can get perspective and what the composition is
at the interior and how the circulation is working. So circulation will bring some species up from
deeper in the atmosphere of the planet to some altitude that's a little bit colder and that
species will condense out and form a cloud at that altitude. And we can detect, in some cases,
what those clouds are composed of. And looking at where those occur can tell you how the
circulation cells are, whether the atmospheric circulation is, say, coming up at the equator
and going down at the poles or whether you have multiple cells in the atmosphere. And I mean,
Jupiter's atmosphere is just insane. There's so much going on. You look at these pictures and
there's all these vortices and anti-vortices and you have these different bands that are moving
in opposite directions that may be giving you information about the deep proper, like deep
in the atmosphere, physically deep properties of Jupiter's interior and circulation.
What are these vortices? What's the basic material of the storms?
It's condensed molecules from the atmosphere. So ammonia ice particles, in the case of Jupiter,
it's methane ice, in the case of, let's say, Uranus and Neptune and other species, you can kind
of construct a chemical model for which species can condense where. And so you see a cloud at a
certain altitude within the atmosphere and you can make a guess at what that cloud is made of.
And sometimes measure it directly and different species make different colors as well.
Oh, cool. Ice storms, okay. I mean, the climate of Uranus has always been fascinating to me because
it orbits on its side and it has a 42-year orbital period. And so, you know, with Earth,
our seasons are because our equator is tipped just a little bit to the plane that we orbit in. So
sometimes the sunlight's a little bit above the equator and sometimes it's a little bit below the
equator. But on Uranus, it's like for 10 years, the sunlight is directly on the north pole and
then it's directly on the equator and then it's directly on the south pole. And it's actually
kind of amazing that the atmosphere doesn't look crazier than it does. But understanding how,
taking again, like one of these extreme examples, if we can understand why that atmosphere behaves
in the way it does, it's kind of a test of our understanding of how atmosphere is.
So like heats up one side of the planet for 10 years and then freezes it the next, like,
and that you're saying should probably lead to some chaos and it doesn't.
The fact that it doesn't tells you something about the atmosphere. So atmospheres have a property
that surfaces don't have, which is that they can redistribute heat a lot more effectively.
Right. So they're a stabilizing, like self-regulating aspect to them that they're able to deal with
extreme conditions. But predicting how that complex system unrolls is very difficult,
as we know, about predicting the weather on Earth, even with a little variation we have on Earth.
You know, people have tried to put together a global circulation model. So, you know, we've done
this for Earth. People have tried to do these for other planets as well. And it is a really hard
problem. So Titan, for example, like I said, it's one of the best studied atmospheres in the solar
system. And people have tried to make these global circulation models and actually predict what's
going to happen moving into sort of the next season of Titan. And those predictions have ended
up being wrong. And so then, you know, I don't know, it's always exciting when a prediction is
wrong because it means that there's something more to learn, like your theory wasn't sufficient.
And then you get to go back and learn something by how you have to modify the theory to make it fit.
I'm excited by the possibility one day there'll be for various moons and planets,
there'll be like news programs reporting the weather with the fake confidence of like as if
you can predict the weather. We talked quite a bit about planets and moons. Can we talk a little
bit about asteroids? For sure. What is what's an asteroid and what kind of asteroids are there?
So the asteroids, let's talk about just the restricted to the main asteroid belt, which is
the region. It's a region of debris basically between Mars and Jupiter. And
the these sort of belts of debris throughout the solar system, the outer solar system,
you know, the Kuiper belt that we talked about, the asteroid belt, as well as
certain other populations where they accumulate because they're gravitationally more favored.
Our remnant objects from the origin of the solar system, and so one of the reasons
that we are so interested in them, aside from potentially the fact that they could come hit
Earth, but scientifically, it gives us a window into understanding the composition
of the material from which Earth and the other planets formed and how that material was kind of
redistributed over the history of the solar system. So the asteroids, one could classify them in two
different ways. Some of them are ancient objects, so they accreted out of the sort of disc of material
that the whole solar system formed out of and have kind of remained ever since more or less the same.
They've probably collided with each other and we see all these collisional fragments and you can
actually look and, based on their orbit, say, you know, like these 50 objects originated as the same
object. You can see them kind of dynamically moving apart after some big collision.
And so some of them are these ancient objects, maybe, that have undergone collisions. And then
there's this other category of object that is the one that I personally find really interesting,
which is remnants of objects that could have been planets. So early on, a bunch of potential
planets accreted that we call planetesimals and they formed and they formed with a lot of energy
and they had enough time to actually differentiate. So some of these objects differentiated into
cores and mantles and crusts. And then they were subsequently disrupted in these massive
collisions. And now we have these fragments. We think fragments floating around the asteroid belt
that are like bits of mantle, bits of core, bits of crust, basically.
Oh, cool. So it's like puzzle pieces that you might be able to stitch together. Or I guess it's
all mixed up. So you can't stitch together the original planet candidates. Or is that possible?
To try to see if they kind of... I mean, there's too many objects in there.
I think that there are cases where people have kind of looked at objects and by looking at
their orbits, they say these objects should have originated together, but they have very
different compositions. And so then you can hypothesize maybe they were different fragments
of differentiated objects. But one of the really cool things about this is we've been talking about
getting clues into the interiors of planets. We've never seen a planetary core or deep mantle
directly. Some mantle material comes up on our surface and then we can see it, but in sort of
in bulk. We haven't seen these things directly. And these asteroids potentially give us a chance
to look at what our own core and mantle is like, or at least would be like if it had been also
floating through space for a few billion years and getting irradiated and all that. But it's a
cool potential window or like analogy into the interior of our own planet.
Well, how do you begin studying some of these asteroids? If you were to put together a study,
what are the interesting questions to ask that are a little bit more specific? Do you find a
favorite asteroid that could be tracked and try to track it through telescopes? Or is it has to
be you have to land on those things to study it? So when it comes to the asteroids, there's so many
of them and the big pictures or the big questions are answered. So some questions can be answered
by zooming in in detail on individual object, but mostly you're trying to do a statistical study.
So you want to look at thousands of objects, even hundreds of thousands of objects and figure out
what their composition is and look at how many big asteroids there are of this composition versus
how many small asteroids of this other composition and put together these kind of statistical
properties of the asteroid belt. And those properties can be directly compared with the results
of simulations for the formation of the solar system. What do we know about the surfaces of
asteroids or the contents of the insides of asteroids and what are still open questions?
So I would say that we don't know a whole lot about their compositions. Most of them are small
and so you can't study them in such detail with telescopes as you could, you know, a planet or
moon. And at the same time, because there are so many of them that you could send a spacecraft to
a few, but you can't really like get a statistical survey with spacecraft. And so a lot of what we,
a lot of what has been done comes down to sort of classification. You look at how bright they are,
you look at whether they're red or blue, simply, you know, whether their spectrum is sloped towards
long wavelengths or short wavelengths. There are certain, if you point a spectrograph at their
surfaces, there are certain features you can see. So you can tell that some of them have silicates
on them. But these are the sort of, they're pretty basic questions. We're still trying to classify
them based on fairly basic information in kind of combination with our general understanding of
the material the solar system formed from. And so you're sort of, you're coming in with prior
knowledge, which is that you more or less know what the materials are the solar system formed
from. And then you're trying to classify them into these categories. There's still a huge amount of
room for understanding them better and for understanding how their surfaces are changing
in the space environment. Is it hard to land on an asteroid? Is this a dumb question? It feels like
it would be quite difficult to actually operate a spacecraft in such a dense field of debris.
Oh, the asteroid belt, there's a ton of material there, but it's actually not that dense. It is
mostly open space. So mentally, do picture like mostly open space with some rocks. The problem
is some of them are not thought to be solid. So some of these asteroids, especially these core
mantle fragments, you can think of as sort of solid like a planet. But some of them are just
kind of aggregates of material. We call them rubble piles. And so there's not necessarily...
Might look like a rock, but do a lot of them have kind of clouds around them? Like a dust cloud thing?
Or like, do you know what you're stepping on when you try to land on it?
Like, what are we supposed to be visualizing here? There's like very few of water, right?
There's some water in the outer part of the asteroid belt, but they're not quite like comets.
In the sense of having clouds around them, there are some crazy asteroids that do become
active like comets. That's the whole other category of thing that we don't understand.
But their surfaces, I mean, we have visited some, you can find pictures that spacecraft
have taken of them. We've actually scooped up material off of the surface of some of these
objects. We're bringing it back to analyze it in the lab. And there's a mission that's launching
next year to land on one of these supposedly core fragment objects to try to figure out
what the heck it is and what's going on with it. But the surfaces, you can picture a solid surface
with some little grains of sand or pebbles on it and occasional boulders, maybe some fine,
dusty regions, dust kind of collecting in certain places.
Is there, do you worry about this? Is there any chance that one of these
fellows destroys all of human civilization by an asteroid kind of colliding with something,
changing its trajectory and heading its way towards Earth?
That is definitely possible. And it doesn't even have to necessarily
collidously and change its trajectory. We're not tracking all of them. We can't track all of them
yet. You know, there's still a lot of them. People are tracking a lot of them and we are
doing our best to track more of them, but there are a lot of them out there and it would be
potentially catastrophic if one of them impacted Earth.
Have you, are you aware of this Apophis object? So there's an asteroid, a near-Earth
object called Apophis that people thought had a decent probability of hitting Earth in 2029
and then potentially again in 2036. So they did a lot of studies. It's not actually going to hit
Earth, but it is going to come very close. It's going to be visible in the sky and are
relatively dark. I mean, not even that dark, probably not visible from Los Angeles, but
and it's going to come a tenth of the way between the Earth and the Moon. It's going to come closer
apparently than some geosynchronous communication satellites. So that is a close call, but people
have studied it and then apparently are very confident it's not actually going to hit us,
but it wasn't. I'm going to have to look into this because I'm very sure, I'm very sure what's
going to happen if an asteroid actually hits Earth, that the scientific community and government
will confidently say that we have nothing to worry about, it's going to be a close call.
And then last minute they'll be like, there was a miscalculation. They're not lying, it's just like
the space of possibilities because it's very difficult to track these kinds of things. And
there's a lot of complexities involved to this. There's a lot of uncertainties. Something tells
me that human civilization will end with, we'll see it coming and then last minute there'll be
oops, we'll see it coming and we'll be like, no, it's just threatening, but no problem, no problem.
And last minute it'll be like, oops, there was a miscalculation and then it's all over
in a matter of like a week. Or just very positive and optimistic today. Is there any chance that
Bruce Willis can save us in the sense that from what you know about asteroids, is there something
that you can catch them early enough to change volcanic eruptions, drill, put a nuclear weapon
inside and break up the asteroid or change its trajectory? There is potential for that if you
catch it early enough in advance. I think in theory, if you knew five years in advance,
depending on the objects and how close, how much you would need to deflect it,
you could deflect it a little bit. I don't know that it would be sufficient in all cases.
And this is definitely not my specific area of expertise, but my understanding is that
there is something you could do. But it also, how you would carry that out depends a lot on
the properties of the asteroid. If it's a solid object versus a rubble pile, so let's say you
planted some bomb in the middle of it and it blew up, but it was just kind of a pile of material
anyway, and then that material comes back together and then you kind of just have the same thing,
the same thing. Presumably its trajectory would be altered, but it's-
That's like Terminator 2, when it's like the thing that's just like you shoot it in splashes
and then comes back together. It would be very useless. That's fascinating. And what's fascinating,
I've gotten a lot of hope from watching SpaceX rockets that land. There's so much, it's like,
oh wow, from an AI perspective, from a robotics perspective, wow, we can do a hell of an amazing
job with control. But then we have an understanding about surfaces here on Earth. We can map up a
lot of things. I wonder if we can do that some kind of detail of being able to have that same
level of precision in landing on surfaces with as wide of a variety as asteroids have. So be able
to understand the exact properties of the surface and be able to encode that into whatever rocket
that lands, sufficiently to- I presume humans, unlike the movies, humans would likely get in the
way. Like it should all be done by robots. And like land, drill, place the explosive,
that should all be done through control, through robots. And then you should be able to dynamically
adjust to the surface. The flip side of that for a robotics person, I don't know if you've seen
these, it's been very heartbreaking. Somebody, I know well, Russ Tedrick at MIT led the DARPA
robotics challenge team for the humanoid robot challenge. For DARPA, I don't know if you've
seen videos of robots on two feet falling. But you're talking about millions, several years of
work with some of the most brilliant roboticists in the world, millions of dollars, and the final
thing is a highlight video on YouTube of robots falling. But they had a lot of trouble with uneven
surfaces. That's basically what you have to do with the challenge involves you're mostly autonomous
with some partial human communication. But that human communication is broken up, like you don't
get a, you get a noisy channel. So you can, humans can, which is very similar to what it would be like
in humans remotely operating a thing on an asteroid. And so with that, robots really struggle.
There's some hilarious, painful videos of like a robot not able to like open the door. And then
it tries to open the door without like misses the handle and in doing so like falls. I mean, it's
painful to watch. So like that there's that and then there's SpaceX. So I have hope from SpaceX.
And then I have less hope from by Peter robotics. But it's fun. It's fun to kind of imagine. And
I think the planetary side of it comes into play and understanding the surfaces of these asteroids
more and more, that, you know, forget sort of destruction of the human civilization, it'd be
cool to have like spacecraft just landing on all these asteroids to study them at scale. And being
able to figure out dynamically, what, you know, whether it's a rubble pile or whether it's a solid
object deck, do you see that kind of future of science, maybe 100, 200, 300 years from now,
where there's just robots expanding out through the solar system, like sensors, essentially,
some of it taking pictures from a distance, some of them landing, just exploring and giving us data.
Because it feels like we're working with very little data right now.
Sure. I do see exploration going that way. I think
the way that NASA is currently, or historically is when doing missions is putting together these
really large missions that do a lot of things and are extremely well tested and have a very
low rate of failure. But now that these sort of CubeSat technologies are becoming easier to build,
easier to launch, they're very cheap. And, you know, NASA is getting involved in this as well.
There's a lot of interest in these missions that are relatively small, relatively cheap,
and just do one thing. So you can really optimize it to just do this one thing. And maybe you could
build 100 of them and send them to different asteroids. And they would just collect this one
piece of information from each asteroid. It's a kind of different, more distributed way of
doing science, I guess. And there's a ton of potential there. I agree.
Let me ask you about objects or one particular object from outside our solar system. We don't
get to study many of these, right? They don't get stuff that just flies in out of nowhere
from outside the solar system and flies through. Apparently, there's been two recently.
In the past few years, one of them is Amua Mua. What are your thoughts about Amua Mua?
So fun to say. Could it be space junk from a distant alien civilization, or is it just
a weird-shaped comet? I like the way that's phrased. So, Amua Mua is a fascinating object,
just the fact that we have started discovering things that are coming in from outside our
solar system is amazing and can start to study them. And now that we have seen some, we can design
now kind of thinking in advance. The next time we see one, we will be much more ready for it.
We will know which telescopes we want to point at it. We will have explored whether we could even
launch a fast turnaround mission to actually get to it before it leaves the solar system.
In terms of Amua Mua, yeah, for an object in our solar system, it's really unusual
in two particular ways. One is the dimensions that we don't see natural things in our solar
system that are kind of long and skinny. The things we see in our solar system don't deviate
from spherical by that much, and then that it showed these strange properties of accelerating
as it was leaving the solar system, which was not understood at first. So, in terms of the
alien space junk, as a scientist, I cannot rule out that possibility. I have no evidence to the
contrary. However- See, you're saying there's a chance. I cannot, as a scientist, honestly say
that I can rule out that it's alien space junk. However, I see the kind of alien explanation
as following this, the Sagan's extraordinary claims require extraordinary evidence. If you
are going to actually claim that something is aliens, you need to carefully evaluate,
one needs to carefully evaluate the other options, and see whether it could just be
something that we know exists that makes sense. In the case of Amua Mua, there are explanations
that fit well within our understanding of how things work. So, there are two hypotheses for
what it could be made of. They're both basically just ice shards. In one case, it's a nitrogen
ice shard that came off of something like Pluto. In another solar system, that Pluto got hit with
something and broke up into pieces, and one of those pieces came through our solar system.
In the other scenario, it's a bit of a failed solar system. Our solar system formed out of a
collapsing molecular cloud. Sometimes those molecular clouds are not massive enough,
and they sort of collapse into bits, but they don't actually form a solar system, but you end
up with these chunks of hydrogen ice, apparently. One of those chunks of hydrogen ice could have
got ejected and passed through our solar system. So, both cases explain these properties in about
the same way, so those ices will sublimate once they've passed the sun, and so as they're moving
away from the sun, you have the hydrogen or nitrogen ice sublimating off the sunward part
of it, and so that is responsible for the acceleration. The shape also, because you have
all this ice sublimating off the surface, if you take something, the analogy that works pretty
well here is for a bar of soap. Your bar of soap starts out sort of close to spherical, at least
from a physicist's perspective, and as you use it over time, you eventually end up with this long,
thin shard, because it's been just by sort of weathering, as we would call it.
And so, in the same way, if you just sublimate material off of one of these ice shards, it ends
up long and thin, and it ends up accelerating out of the solar system, and so given that these
properties can be reasonably well explained that way, we should be extremely skeptical
about attributing things to aliens. See, the reason I like to think that it's aliens
is because it puts a lot of priority on us not being lazy, and we need to catch this thing
next time it comes around. I like the idea that there's objects, not like, it almost saddens
me, they come out of the darkness really fast, and just fly by and go and leave. It just seems
like a wasted opportunity not to study them. It's like, it's the easiest way to do space travel
outside of the solar system. It's having the things come to us. I like that way of putting it.
And it would be nice to just land on it, and first of all, really importantly, detect it early,
and then land on it with a really nice spacecraft and study the hell out of it.
If there's a chance it's aliens, alien life, it just feels like such a cheap way, inexpensive way,
to get information about alien life or something interesting that's out there.
I'm not sure if an ice shard from another planetary system will be interesting,
but it very well could be. It could be totally new sets of materials. It could be,
tell us about composition of planets we don't quite understand. And it's just a nice one,
especially in the case of a more and more, I guess it was pretty close to Earth. It would have been
nice to, you know, don't go there, they come to us. I don't know. That's what makes me,
that's what makes me quite a sad. It's a missed opportunity.
Well, yeah, and whether you think it's aliens or not, it's a missed opportunity, but, you know,
we weren't prepared, and we will be prepared for the next ones. And as, so there's been a movement
in astronomy more towards what's called time domain astronomy, so kind of monitoring the whole
sky all the time at all wavelengths, that's kind of the goal. And so we expect to detect many more
of these in the future, even though these were the first two we saw, our potential to detect them
is only increasing with time. And so there will be more opportunities. And, you know, based on these
two, we now can actually sit and think about what we'll do when the next one shows up.
I also, what it made me realize, I know I didn't really think through this, but it made me realize
if there is alien civilizations out there, the thing we're most likely to see first would be
space junk, my stupid understanding of it. And the second would be really dumb kind of,
you could think of maybe like relay nodes or something, objects that you need to have a whole
lot of for particular purposes of like space travel and so on, like speed limit signs or
something, I don't know, whatever we have on earth, a lot of that's dumb. It's not alien,
aliens and themselves, it's like artifacts that are useful to the engineering in the
systems that are engineered by alien civilizations. So like, it would, we would see a lot of stuff
in terms of setting, in terms of looking for alien life and trying to communicate with it,
maybe we should be looking not for like smart creatures or systems to communicate with,
maybe we should be looking for artifacts or even as dumb as like space junk.
It just kind of reframed my perspective of like, what are we looking for as science?
Because there could be a lot of stuff that doesn't have intelligence but gives us really strong signs
that there's somewhere is life or intelligent life. And yeah, that made me kind of, I know it
might be dumb to say, but reframe the kind of thing that we should be looking for. Yeah, it's,
so the benefit of looking for intelligent life is that we perhaps have a better chance of recognizing
it. Yeah, we couldn't necessarily recognize what an alien stop sign look like. That's true.
And maybe, you know, the theorists are the people who sort of model and try to understand
slow system objects are pretty good at coming up with models for anything. I mean,
it's maybe a Muamua was a stop sign, but we're clever enough that we could come up with some
physical explanations for it. And then, you know, we all want to go with the simplest possible,
we all want to believe the sort of most skeptical possible explanation. And so we missed it because
we're too good at coming up with alternate explanations for things. And it's such an
outlier, such a rare phenomena that we can't, we can't study, you know, 100 or 1000 of these
objects, we have to we had just one. And so the science almost destroys the possibility of
something special being there. It's like a Johnny I've this designer of Apple, I don't know if you
know who that is, he's the lead designer, he's the person who designed the iPhone and all the major
things. And he talked about he's brilliant on my favorite humans on earth, and one of the best
designers in the history of earth. He talked about like when he had this origins of an idea,
like in his baby stages, he would not tell Steve Jobs, because Steve would usually like
trample all over it. He would say this is dumb idea. And so I sometimes think of the scientific
community in that sense, because the the weapon of the scientific method is so strong at its best,
that it sometimes crushes the out of the box outlier evidence. You know, we don't get a lot
of that evidence, because we don't have we're not lucky enough to have a lot of evidence. So we
have to deal with just special cases. And special cases could present an inkling of something much
bigger. But the scientific method user tramples all over and it's hard to know what to do with that,
because the scientific method works. But at the same time, every once in a while, it's like a
balance. You have to do 99% of the time you have to do like scientific rigor. But every once in a
while, this is not you saying me saying smoke some weed and sit back and think, I wonder,
you know, it's the Joe Rogan thing, it's entirely possible that it's alien space junk.
Anyway, yeah, I think so I completely agree. And I think that most scientists do speculate
about these things. It's just at what point do you act on those things? So you're right that
the scientific method has inherent skepticism. And for the most part, that's a good thing,
because it means that we're not just believing crazy things all the time. But it's an interesting
point that requiring that high level of rigor occasionally means that you will miss
something that is truly interesting, because you needed to verify it three times, and it
wasn't verifiable. I also think like when you communicate with the general public,
I think there's power in that 1% speculation of just demonstrating authenticity as a human
being as a curious human being. I think too often, I think this is changing, but I saw,
I've been quite disappointed, my colleagues throughout 2020 with the coronavirus, there's
too much speaking from authority, as opposed to speaking from curiosity. There's some of the most
incredible science has been done in 2020, especially on the virology biology side.
And the kind of being talked down to by scientists is always really disappointing to me,
as opposed to inspiring. There's a lot of uncertainty about the coronavirus,
but we know a lot of stuff. And we speak from scientists from various disciplines speak from
data in the face of that uncertainty. And we're curious, we don't know what the hell is going
on. We don't know if this virus is going to evolve, evolve, mutate. We don't know if this virus
or the next one might destroy all of human civilization. You can't speak with certain,
in fact, I was on a survey paper about masks. Something I don't talk much about, because
I don't like politics. But we don't know if masks work, but there's a lot of evidence to show that
they work for this particular virus. The transmission of the virus is fascinating, actually.
The biomechanics of the way viruses spread is fascinating. If it wasn't destructive,
it would be beautiful. And we don't know, but it's inspiring to apply the scientific method
to the best of our ability, but also to show that you don't always know everything and to,
perhaps not about the virus as much, but other things speculate. What if it's the worst case
and the best case? Because that's ultimately what we are, descendants of apes that are just curious
about the world around us. Yeah, I'll just add to that, not on the topic of masks, but on the topic
of curiosity. Astronomy and planetary sciences field are unique because for better and for worse,
they don't directly impact humanity. We're not studying biology to prevent transmission of
illness amongst humans. We're not characterizing volcanoes on earth that could destroy cities.
It really is a more curious and, in my opinion, playful scientific field than many. So for better
and worse, we can kind of afford to pursue some of the speculation more because human lives are
not in danger if we speculate a little bit too freely and get something wrong. Yeah, definitely.
In the space of AI, I am worried that we're sometimes too eager, speaking for myself,
to flip the switch on just to see what happens. Maybe sometimes we want to be a little bit
careful about that because bad things might happen. Is there books or movies in your life
long ago or recently that were inspiring, had an impact on you that you would recommend?
Yeah, absolutely. So many that just don't know where to start with it. So I love reading. I read
obsessively. I've been reading fiction and a little bit of nonfiction, but mostly fiction,
obsessively, since I was a child and just never stopped. So I have some favorite books. None of
them are easy reading. So I definitely, I mean, I recommend them for somebody who likes an
intellectual challenge in the books that they read. So maybe I should go chronologically. I have
at least three. I'm not going to go through 50 here. Yeah, I'd love to also maybe ideas that you
took away from what you mentioned. Yeah, yeah, why they were so compelling to me. One of the first
books that really captured my fascination was Nabokov's book, Pale Fire. Are you familiar with
it? So I read it actually for a class. It's one of the few books I've ever read for a class that
I actually really liked. And the book is, it's in some sense a puzzle. He's a brilliant writer,
of course. But the book is like, it's formatted like a poem. So there's an introduction, a very long
poem and footnotes. And you get partway through it before realizing that the whole thing is actually
a novel unless you sort of read up on it going in. But the whole thing is a novel and there's a story
that slowly reveals itself over the course of all of this and kind of reveals this
just fascinating character, basically, and how his mind works in this story. The idea of a novel
also being a kind of intellectual puzzle and something that slowly reveals itself over the
course of reading was really fascinating to me. And I have since found a lot more writers like
that. You know, contemporary example that comes to mind is Kazuo Ishiguro, who's pretty much
all of his books are like slow reveals over the course of the book. And like nothing much
happens in the books, but you keep reading them because you just want to know like what the
reality is that he's slowly revealing to you. The kind of discovery oriented reading, maybe.
What's the second one? Perhaps my favorite writer is Renea Maria Rilke.
Are you familiar with him? You're hitting one. I mean, I know in the book of Well,
but I've never read Pale Fire. But Rilke, I've never, I know it's a very difficult read.
I know that much. Yeah, right. All of these are difficult reads. I think I just,
I read for in part for an intellectual challenge. But Rilke, so he wrote one thing that might be
characterizable as a novel, but he wrote a lot of poetry. I mean, he wrote this series of poems
called the Duino Elegies that were very impactful for me personally, just emotionally,
which actually it kind of ties in with astronomy in that there's there's a sense,
you know, in which we're all going through our lives alone. And there's just this sense of kind
of profound loneliness in the existence of every individual human. And I think I was drawn to
astronomy in part because the sort of vast spaces, the kind of loneliness and desolateness of space
made the sort of internal loneliness feel okay. In a sense, it like gave companionship and
that's how I feel about Rilke's poetry. He turns the kind of desolation and loneliness of human
existence into something joyful and almost meaningful. Yeah, there's something about
melancholy, I don't know about Rilke in general, but like contemplating the
melancholy nature of our of the human condition that makes it okay.
Like I got gentle from an engineering perspective, think that there is so much loneliness we haven't
explored within ourselves yet. And that's my hope is to build AI systems that help us explore our
loneliness. I think that's kind of what love is and friendship is is somebody who in a very small
way helps us explore our own loneliness, like they listen to connect like two lonely creatures
connect for a time that's like, oh, like acknowledge that we exist together, like for a brief time.
But in a somewhat shallow way, I think relative to how much it's possible to truly connect this
two consciousnesses, so AI might be able to help on that on that front. So what's the third one?
Actually, you know, I hadn't realized until this moment, but it's yet another one of these kind of
slow reveal books. It's a contemporary Russian, I think Russian American writer named Olga Grushin,
G-R-U-S-H-I-N. And she wrote this just phenomenal book called The Dream Life of Sukhanov that I
read this year, maybe it was last year for the first time. And it's just a really beautiful,
this one you could call a character study, I think, of a Russian father coming to terms with
himself and his own past, as he potentially slowly loses his mind.
Slow reveal. Slow reveal.
Well, that's apparent from the beginning. I hope I don't think it's a spoiler.
Declining to madness. Spoiler alert. So all of these are really heavy. I don't know. I just,
I don't have anything lighter to recommend. Ishii grows the light version of this.
Oh, well, heavy has a certain kind of beauty to it in itself. Is there advice you would give to a
young person today that looks up to the stars and wonders what the heck they want to do with their
life? So career, science, life in general, you've for now chosen a certain kind of path of curiosity.
What insights do you draw from that that you can give us advice to others?
I think for somebody, I would not presume to speak to giving people advice on life and humanity
overall, but for somebody thinking of being a scientist. So there are a couple of things,
one sort of practical thing, which is career-wise, I hadn't appreciated this going into science, but
you need to, so the questions you're working on and the techniques you use are both
of very high importance, maybe equal importance for being happy in your career.
If there are questions you're interested in, but the techniques that you need to use to do them
are tedious for you, then your job is going to be miserable, even if the questions are inspiring.
So you have to find, but if the techniques that you use are things that excite you,
then your job is fun every day. So for me, I'm fascinated by the solar system and I love telescopes
and I love doing data analysis, playing with data from telescopes, coming up with new ways to use
telescopes. And so that's where I have found that mesh. But if I was interested in the
dynamical evolution of the solar system, how the orbits of things evolve, then I would need to do
a different type of work that I would just not find as appealing and so it just wouldn't be a good
fit. And so it sort of seems like an unromantic thing to have to think about the techniques
being the thing you want to work on also, but it really makes a profound difference for,
I think, your happiness and your scientific career.
I think that's really profound. It's like the thing, the menial tasks. If you enjoy those,
that's a really good sign that that's the right path for you. I think David Foster Wallace said
that the key to life is to be unboreable. So basically, everything should be exciting. I
don't think that's feasible, but you should find an area where everything is exciting,
I mean, depending on the day, but you can find the joy in everything, not just the big exciting
chronicle things that everyone thinks is exciting, but the details, the repetitive stuff, the
mean stuff, the stuff that takes years, the stuff that involves a lot of failure and all those kinds
of things that you find that enjoyable. That's actually really profound to focus on that,
because people talk about dreams and passion and goals and so on, the big thing, but that's not
actually what takes you there. It takes you there as every single day, putting in the hours,
and that's what actually makes up life is the boring bits. If the boring bits aren't boring,
then that's an exciting life. Because when you were talking so romantically and passionately
about IO, I remember the poem by Robert Frost. So let me read the poem and ask
what your opinion is. That's called Fire and Ice. Oh, yeah. I could almost recite this from memory.
Some say the world will end in fire, some say in ice. From what I've tasted of desire,
I hold with those who favor fire. But if I had to perish twice, I think I know enough of hate
to say that for destruction, ice is also great and will suffice. So let me ask,
if you had to only choose one, would you choose the world to end in fire, in volcanic eruptions,
in heat, and magma, or in ice frozen over? Fire or ice? Fire.
Excellent choice. I've always been a fan of chaos. The idea of things just
slowly getting cold and stopping and dying is just so depressing to me. So much more depressing than
things blowing up or burning and they're getting covered by a lava flow. Somehow the activity of
it endows it with more meaning to me, maybe. I've just now had this vision of you,
in action films where you're walking away without looking back and there's explosions behind you
and you just put on shades and then it goes to credits. Catherine, this was awesome. I think your
work is really inspiring. The kind of things we'll discover about planets in the next few decades
is super cool and I hope, I know you said there's probably not life in one of them,
but there might be and I hope we discover just that. And perhaps even on Io,
within the volcanic eruptions, there's a little creature hanging on that we'll one day discover.
Thank you so much for wasting all your valuable time with me today. It was really awesome.
Yeah, likewise. Thank you for having me here.
Thanks for listening to this conversation with Catherine de Cleer and thank you to
Fundrise, Blinkist, ExpressVPN, and Magic Spoon. Check them out in the description to support this
podcast. And now, let me leave you with some words from Carl Sagan. On Titan, the molecules that have
been raining down like mana from heaven for the last four billion years might still be there,
largely unaltered, deep frozen, awaiting for the chemists from Earth. Thank you for listening and
hope to see you next time.