Kind: captions
Language: en
the following is a conversation with
catherine declare 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 quick mention of our
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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 were 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 various small
projects
if this is something of interest to you
go to lexfriedman.com
hiring that's where i will always post
opportunities for
working with me this is the lex friedman
podcast
and here is my conversation with
catherine to clear
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
would just love for pluto to still be a
planet um
but the the reality is um when we first
discovered pluto it was it was a unique
object in the outer solar system and we
thought
you know we were adding a planet to the
inventory of planets that we had and
then
over time it became clear that pluto was
not
a unique large object in the outer solar
system that there were actually
many of these and as we started
discovering more and more of them we
realized that the concept of pluto being
a planet
um 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
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
um so the 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 this
belt of debris out there in the outer
solar system of things with a range of
sizes
um is there a hope for clear
categorization
of what is a planet and not give us or
is it all just gray area
when you study planets when you study
moons satellites of those planets
is there lines that are cl that could be
cleanly drawn or is it just a giant mess
this is all like a fluid let's say not
mess but it's like fluid
uh of what is a planet what is the 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
um is it size related like what are the
parameters based on 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
um so it has to order uh 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 has
have cleared out its orbital path um
and because pluto orbits in a belt of
material it doesn't satisfy
that stipulation why didn't it clear out
the path it's not big enough
right knock everybody out of the way um
and this actually is not the first time
it has happened so
series 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 and 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 i it is important just for having a
general framework
for for understanding and talking about
things to have a precise definition
so you don't have a special romantic
like appreciation of a moon versus a
planet versus an asteroid it's just an
object that flies out there and doesn't
really matter
what the categorization is because
there's movies about asteroids and stuff
and then there's like and then there's
movies about you know
the moon whatever it's a really good
movie
you know there's something about moons
that uh that's almost like
an outlier like you think of a moon
as a thing that's the secret part and
the planet
is like the more like vanilla regular
part
none of that you don't have any of that
no i actually do i really satellites are
the moons are my favorite things in the
solar system and i think part of
what you're saying i agree from
maybe a slightly different perspective
which is from the perspective of
exploration
we've spent a lot of time sending
spacecraft missions to planets we had a
mission to jupiter we had a mission to
saturn we have plenty of missions to
mars and missions to venus
i think that exploration of the moons in
the outer solar system is
the next frontier of solar system
exploration
the belt of debris just real quick
that's out there
is there something incredible to be
discovered there
again we tend to focus on the planets
and the moons but it feels like
there's probably a lot of stuff out
there and it probably
what is it it's like a garbage collector
from
outside of the solar system isn't it
like doesn't it protect
from other objects that kind of fly in
and what it just feels like
it's a cool you know you know when you
like walk along the beach and look for
stuff
and like look for sure it feels like
that's that kind of place where you can
find cool
cool weird things or it 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 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 it's 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 i
think what you fit on is exactly right
that we just don't have the tools to
study them in detail
but we 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
disc 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 the
realm of like how would you even design
devices or sensors that go out there
and take pictures and 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
um 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
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 it's sad because
you know like when you're on a deserted
island you wave your hands and the thing
flies by and you're
trying to get their attention and they
probably do the same
well in their own way bacteria probably
right but
and we we miss it i don't know some
reason it makes me it's a
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 uh a sad uh
pause uh 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 um
so among the fields 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
um and planets
the solar system is really unique in
that we can actually send
spacecraft missions to the objects and
study them in detail and so i think
that's that's the kind of type of tool
that is that people are most aware of
this most popular eyes
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 um
trying to detect tectonic tremors on its
surface
um the types of tools that i use
are primarily telescopes and so i my
background is in
astrophysics and so i actually got into
solar system science from
astronomy not from you know a childhood
fascination with spacecraft missions
which is actually what
a lot of planetary scientists became
planetary scientists because of
childhood fascination with spacecraft
missions which is kind of interesting
for me to talk to people and see that
trajectory i kind of came at it from the
fascination with telescope's angle
do you like telescopes not rockets or at
least 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 sheer out in the atmosphere of
titan you can
literally watch volcanoes on io change
from day to day as the 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 at a 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 and actually watch how 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
it's 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
uh just
zoom in on certain things like let's
talk about io which is the moon of
uh jupiter right okay it's like epic
there's like volcanoes all over the
place
it's um from a distance it's awesome
so can you tell me about this moon and
you're
sort of uh 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 uh io is it is
the most volcanically active object in
the solar system it has hundreds of
active volcanoes on it
um 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 um but
i think to me the reason that it's most
interesting is be
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
um 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 the
magma d gases
for something that's really small for
something that has a different heat
source for something that's embedded in
another object's magnetic field
the kind of intuition we have from earth
doesn't apply and so broadly
planetary sciences 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 you completely you uh you kind of
ignored the fact that jupiter exists
it's like let's focus on this
yeah okay so uh and you also didn't
mention europa
which i think is the is that the most
famous moon of jupiter
it's like no one gets attention because
it might have life exactly
yeah but you're but to you i o is also
beautiful
i what's the difference between
volcanoes on io
versus earth you said atmosphere makes a
difference
what uh yeah um the heat source plays a
big role so
um many of the moons in the outer solar
system are heated
from gravitationally by tidal heating um
and i'm
happy to describe what that is or well
yeah please
okay um yes so tidal heating
is it's if you want to understand and
contextualize
planets and moons you have to understand
their heat sources
um 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 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
um and so that tweaks them into
eccentric orbits
so eccentric orbit or elliptical orbit
it just means
non-circular so a deviation from a
circular orbit and that means that you
know for io or europa
it's 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 but
literally just not very stretched out
like a couple hundred meters something
like that
and then when they're farthest away
they're less stretched out and so you
actually have the shape of the object
deforming over the course of the orbit
and these orbits are like just a couple
of days
and so that in the case of io that is
literally
sufficient friction in its mantle to
melt the rock of its mantle
and that's what generates the magma
that's that's the source of the
the okay so why is your so europa
is i thought there was like ice and
oceans underneath kind of thing
so why is europe and not getting the
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 like hydrothermal
vents where we see really interesting
uh life evolve in the bottom of earth's
oceans
that's cool okay so what's uh what's io
um 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
if you and i were to visit io
like what would that look like what
would it feel like
is it is the entire thing covered in
basically
uh volcanoes um
so it's 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 the
magma when it comes out is over a
thousand degrees and so
but it does come to the surface the
magma it does yeah
in particular places oh that probably
looks beautiful
so like so it's frozen not ice like what
is
uh is rock it's really cold rock
and then you just have this like uh
what is what does that look what would
that look like with no atmosphere
would that uh would it be smoke
what does it look like was it's just
magma like just red
yellow like liquidy things uh it's
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
um and i think the the lava flows that
we've been having
in hawaii over the past couple years are
probably a decent analogy although um
ios magmas lavas are even more fluid and
and faster moving like what uh how fat
like
if you oh by the way sorry through the
telescope
are you tracking at what time scale like
what the for every frame
is how far apart if you're looking for a
telescope are we talking about
seconds or we're talking about days
months
when you kind of track try to get a
picture of what the surface might look
like
what's the frequency so it depends a
little bit on what you want to do
i ideally every night
but you could take a frame every second
and see how things are changing
the the problem with that is that for
things to change on a one
second time scale you to actually see
something change that fast you have to
have super high resolution the spatial
resolution we have is a couple hundred
kilometers and so
okay things are not changing on those
scales over one second unless you have
something really crazy happening
so if you get you if you get a telescope
closer to io
if you get uh or a camera closer to io
would you be able to understand
something is that something of interest
to you
it would you be able to understand
something deeper about
these volcanic eruptions and how magma
flows and
just the like the rate of the magmas or
is it basically
enough to have the kilometer resolution
no way
we want to go there you want to go you
want to go to iowa 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
like i don't want to go there as a human
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 uh but it's not
hospitable to uh
humans in any way right so it's very
cold and very hot
it's very cold um the atmosphere is
composed of sulfur dioxide
so you couldn't breathe it there's no
pressure i mean it's kind of all the
same things you talk about
one talks about about mars only worse
the atmosphere is still a thousand times
less dense than mars's
and the radiation environment is
terrible because you're embedded
deep within jupiter's magnetic field and
jupiter's magnetic field is
full of charged particles that have all
come
out of ios volcanoes actually um so
juveder's magnetic field strips all this
material out of ios atmosphere
and that populates its entire
magnetosphere and then that material
comes back around and hits io and
spreads throughout the system actually
it's just
it's like a io is the massive polluter
of the jupiter system
okay cool uh so what uh what is studying
io
uh teach you about volcanoes on earth or
vice versa
is in the difference of the two
what uh insights can you mine out
that might be interesting in some way
yeah it's
we try to port the tools that we use to
study earth volcanism to io and it works
to some extent but
it is challenging because the
situations are so different and the
compositions are really different when
you talk about
outgassing you know earth volcanoes
outgas primarily
water and carbon dioxide and then sulfur
dioxide is the the third
most abundant gas and 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 so the
chemistry of how the magma outgasses is
completely different
um but the the kind of one to me
most interesting analogy to earth is
that
um so io as i've said it has these
really low viscosity magmas the
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
um 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 uh what are the chances
that uh a volcano on earth destroys all
of human civilization
maybe i wanted to sneak in that question
yeah a volcano on earth
um do you think about that kind of stuff
when you just
study volcanoes elsewhere because in it
kind of humbling to see something so
powerful
and so hot like so unpleasant for humans
and then you realize we're sitting on
many of them here right
yeah yellowstone as a classic example i
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
so that in the time
you know that maybe it'll happen
eventually that there will be one of
these massive volcanoes on earth but
we'll probably be gone by then by some
other means
not to sound bleak but it's very
comforting
okay so can we talk about um europa
is there um so maybe can you talk about
the intuition the hope that people have
about life being in europa
maybe also what are the things we know
about it
what are things to you that are
interesting about that particular moon
of jupiter
sure yeah europa is from many
perspectives one of the really
interesting
places in the solar system among the
solar system moons so there are a few
there has there's a lot of interest in
looking for or understanding the
potential for life to evolve in the
subsurface oceans
i think it's fairly widely accepted that
the chances of life evolving on the
surfaces of really anything in the solar
system is very low
the radiation environment is too harsh
and there's there's just not liquids on
the surface of most of these things and
it's canonically accepted that liquids
are required for life
um and so the subsurface oceans in
addition to maybe titan's atmosphere the
subsurface oceans of the icy satellites
uh are one of the most plausible places
in the solar system for life to evolve
europa and enceladus 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 um 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 uh 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
water interface is is considered really
important
for the potential habitability
as a small aside you kind of said that
it's canonically assumed that
uh light water is required for life
is it possible to have life uh like in
the volcano
i remember people are at that like in
that
national geographic program or something
kind of hypothesizing that you can
really have life anywhere so as long as
there's a source of heat
a source of energy do you think it's
possible to have
life in a volcano like no water
i think anything's possible
i think it's so water it doesn't have to
be
water that's sort of you can tell as you
identified i phrased that really
carefully it's canonically accepted that
um because we recognize that you know
scientists recognize that we have no
idea
what broad range of life could be out
there and all we really have is our
biases of life as we know it
but for life as we know it it's very
helpful to have or even necessary to
have some kind of
liquid and preferably a polar solvent
that can actually dissolve molecules
something like water so the case of
liquid methane on titan is less ideal
from that perspective
but you know liquid magma if it stays
liquid
long enough for life to evolve you have
a heat source you have a liquid you have
nutrients in theory that checks your
three
classic astrobiology boxes
um that'd be fascinating i mean it'd be
fascinating if it's possible to detect
it easily
how would we detect if there is life on
europa
is um 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 um
there's so europa also has these long
tectonic features on its surface where
it's thought that
there's potential for water from the
ocean to be somehow making its way
up onto the surface and you could
imagine some out there scenario where
there's bacteria in the ocean it's
somehow working its way up through the
ice shell
it's spilling out on the surface it's
being killed by the radiation
but your instrument could detect some
spectroscopic signature of that
dead bacterium but that's you know
that's many ifs and assumptions
that's a hope because then you don't
have to do that much drilling you can
collect from the surface right or even
i'm thinking even remotely oh remotely
yeah that's sad that there's a
single cell civilization living
underneath all that ice
trying trying trying to get up trying to
get out
so enceladus gives you a slightly better
chance of that
because enceladus is a is a moon of
saturn
and it's broadly similar to europa in
some ways it's an icy satellite it has a
subsurface ocean that's probably
in touch with the rocky interior but it
has these massive
geysers at its south pole where it's
spewing out material that appears to be
originating all the way from the ocean
and so in that case you could
potentially fly through that plume and
scoop up that material and hope that at
the velocities you'd be scooping it up
you're not destroying any signature of
the life you're looking for
but let's say that you have some
ingenuity and can come up with a way to
do that
you know it potentially gives you a more
direct opportunity at least to try to
measure those bacteria directly
can you tell me a little more on uh how
do you pronounce it
enceladus enceladus can you tell me a
little bit more about enceladus
like uh we've been talking about way too
much about jupiter
saturn doesn't get enough
uh saturn doesn't get as much love so
what's what's enceladus uh
is that the most exciting moon of uh
saturn
depends on your perspective um it's it's
very exciting from a
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
um
so what's more likely uh titan or
enceladus for life
if you were to uh bet all your money in
terms of like investing
wish to investigate what 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 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 the
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 what
an atmosphere denser than earth 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 still being freezing cold uh
yes okay what what would that be like
would that be pleasant for humans to
hang out there
it's just really cold there's nowhere in
the solar system that would be pleasant
for humans
um it would be cold you couldn't breathe
the air um
but colonization wise if there's an
atmosphere isn't that a big plus
or still a ton of radiation
so okay so titan
that that's a really nice feature that
the light could be in the atmosphere
because then it's it's that might be
remotely observable or certainly is more
accessible if you visit okay
so uh 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 froze or sorry 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 um cyclical
evolution
where the ocean freezes completely and
thaws completely and the orbit sort of
um oscillates in and out of these
eccentricities um 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 there might be mass extinction
events if it does occur
right it just freezes again very sad man
this is very depressing all the like
slaughter of
life elsewhere how unlikely do you think
life is on earth so when you look
when you study other planets and you
study the contents of other planets
does that give you a perspective on
the origin of life on earth which again
is full of mystery
in itself not the evolution but the
origin
the first springing to life like from
from nothing to life from the basic
ingredients to life
and 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
uh we don't know whether it's happened
anywhere else
in the universe although it feels absurd
to believe
that we are the only life that evolved
in the entire universe but
it's conceivable we just have just no
real information we don't understand
really how life came about in the first
place on earth
i mean so if you look at the drake
equation
that tries to estimate how many alien
civilizations are out there
planets have a big part to play in that
equation
if you were to bet money uh
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 special is earth how rare and
special is the solar system
like if you had to bet all your money on
a
on a completely unscientific question
well no actually it's actually
rigorously scientific we just don't know
a lot of things
in that equation there's a lot of
mysteries about that
and it's slowly becoming better and
better understood in terms of exoplanets
in terms of
how many solar systems are out there
where there's planets their earth-like
planets is
getting better and better understood
what's your sense
from that perspective um how many alien
civilizations out there
so zero or one you're right that the
equation
is 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
and then we're just barely scratching
the surface of what fraction of those
planets might be habitable
the rest of the terms in the equation
are like how likely is life to evolve
give inhabitable conditions how likely
is it to survive all these things
um they're all these huge unknowns
actually i i remember when i first
saw that equation i think i was 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 given name
you know um and b just a bunch of
unknowns it's like
putting our ignorance together in one
equation but i've actually
now i understand this equation you know
it's not
something we ever necessarily have the
answer to it's
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 was put
into writing was to 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 um
i i would
put money on there being aliens i
would not put money on
us having definitive evidence of them in
my lifetime
well definitive is a funny is a funny
word
because uh my sense is this is the
saddest part
for me is my sense in terms of
intelligent alien civilizations
i feel like we're so
we're so self-obsessed that we literally
would not be able to detect them
even when they're like in front of us
like like
trees could be aliens but just their
intelligence could be
realized on a scale on a time scale
or physical scale that we're not
appreciating
like trees could be way more intelligent
than us
i don't know it's just a dumb example it
could be rocks rock
or it could be things like
this i love this this is the dawkins
memes it could be that ideas
are the like ideas we have like where do
ideas come from where do thoughts come
from
maybe thoughts are the aliens or
maybe thoughts is the actual mechanisms
of communication
in uh physics right this is like we
think of thoughts as something that
springs up from neurons
firing where the hell they come from
and now what about consciousness maybe
consciousness is the communication
it sounds like ridiculous but like
we're so self-centered on this uh
space-time
communication and physical space using
like written language
like spoken with audio
on a time scale that's very specific on
a physical scale it's very specific
uh so so i i tend to think that uh but
bacteria will probably recognize like
like moving organisms will probably
recognize but when that forms itself
into intelligence
most likely it'll be robots of some kind
because we won't be making
the origins we'll be meeting the
creations of those
intelligences we just would not be able
to to appreciate it and that's the
saddest thing to me
that uh we we
yeah we when we're too dumb
to see aliens uh like we're two
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 point zero zero
zero one percent 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 that i feel like that's easier for
us to comprehend in the space of biology
and not as easy to comprehend in the
space of physics for example
because we have a sense that like we
have
it like if you if you talk to
theoretical physicists
they have a sense that we understand the
basic laws
that form the nature of reality
of our universe but so there's much more
complex physicists and much more
confident
biologists are like uh
this is a squishy mess we're doing our
best
uh physicists but i would be it'd be
fascinating to see if physicists
themselves would also be humble
by their being like what the hell is
dark matter in dark energy
what what the hell is the not just the
origin of the
not just the big bang but uh everything
that happened since the big bang
a lot of things that happened since the
big bang we have no ideas about except
basic models of physics right
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
center 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
um so that could be a portal for aliens
to communicate through conscious okay
um all right back to planets how um
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 iowa's the
favorite oh absolutely why is iowa the
favorite
i mean basically everything i've i've
already said it's just such an amazing
and unique
object um 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
um and when i started my phd i wanted to
be
an astrophysicist working on things like
galaxy evolution
um and sort of slowly i had done some
projects in the solar system but io was
the thing that like really caught me
in to doing solar system science okay
let's let's leave
uh moons aside what's your favorite
planet
it sounds like you like moons better
than planets so it's uh
that's accurate but the planets are are
fascinating i think
you know i find the planets in the solar
system really fascinating what i like
about the moons
is that they there's so much less that
is
known there's still a lot more discovery
space and the questions that we can ask
are still the the bigger questions
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 but
there is
certainly quite a bit more information
that we have about the planets than the
moons
but i mean venus is is a fascinating
object so
i like the objects that lie at the
extremes
i think that if we can make a sort of
theory or
like i've been saying framework for
understanding planets and moons that can
incorporate even the most extreme ones
then you know those are the things that
really test your
theory and test your understanding and
so they've always really fascinated me
not so much the nice habitable places
like earth but
these extreme places like venus that
have
um 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 the 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 uh
is there a life on venus so the
detection that was reported was the
detection of the molecule phosphine
um 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 um
i don't personally believe that
phosphene was detected in the first
place
okay so i mean this is just one study
but i
as a layman i'm skeptical
a little bit about tools that
sense the contents of an atmosphere like
contents of an atmosphere from remotely
and making conclusive statements about
life
oh yeah well that connection that you
just made the contents of the atmosphere
to the life
yeah 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
uh to claim of life even the detection
itself though
did doesn't doesn't meet the sort of
historical
scientific standards of of a detection
um the it was a very tenuous detection
and only one line of the species was
detected
and a lot of really complicated data
analysis methods had to be
applied to even make that weak detection
yeah
um so it could be it could be noise it
could be polluted data it could be 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 uh
the human species are hopeful to find
life
clearly yes everyone is so excited about
that possibility
all right let's uh let me ask you about
mars
so um there's a guy named elon musk
and uh he seems to want to take
something called dogecoin there
first of the moon i'm just i'm just
kidding about the tushcoin i
i even know what the what the heck is uh
up with that whole uh
i think uh 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
sneak it's like a trojan horse for cool
ideas
you you open with humor and you uh like
the humor is the appetizer and then the
main meal is the science and the
engineering
anyway uh do you think
it's possible to colonize
mars or other planets in the solar
system but we're
especially uh 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 hope we
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 going to mars as
a tourist may go to mars
um i don't think that we will colonize
it um
is there a sense why it's just too harsh
of an environment
to uh 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
um so 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 those things the radiation
environment is too harsh for the human
body
um all of those things seem like they
could eventually have
technological solutions
the challenge the 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 the 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 um 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 would be eating like cockroaches
if we're living on mars because that's
the easiest thing to actually
um as a source of protein so growing a
source of protein is the easiest thing
is
as 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
of insects to make them more radiation
friendly
right or pressure resistant or whatever
it makes them
what can possibly go wrong cockroaches
make them radiation resistant
they're already like survived all
everything plus i um
i took an allergy test i'm in austin so
there's everybody's alert is like the
allergy levels are super high there
uh and one of the things apparently i'm
not allergic to any insects
except cockroaches it's hilarious so
maybe uh um well
i'm gonna use that as you know people
use an excuse that i'm allergic to cats
to not have cats i'm gonna use that as
an excuse to uh
not go to mars as one of the first batch
of people otherwise i was gonna ask if
you had the opportunity would you go
yeah i'm joking about the cockroach
thing and i would definitely go
i love challenges i love i love things
i love doing things where the
possibility of death
is is uh not insignificant
because it makes me appreciate it more
meditating on death makes me appreciate
life
and uh 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
i i uh but it could be because i grew up
in the soviet union there's a kind of
love
for space like the the space race the
cold war created
i don't know if still it permeates
american culture as much
but especially with the dad as a
scientist
i think i've i've loved the idea of
humans striving
out towards the stars always like from
the engineering perspective
has 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 but uh so that's that's
hopeful but for me i always loved that
idea
from uh 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
li