The Search for Life: Exploring Ocean Worlds (live public talk)

The Search for Life: Exploring Ocean Worlds (live public talk)


>>Announcer: NASA’s Jet
Propulsion Laboratory presents the von Karman Lecture. A series of talks by
scientists and engineers who are exploring our
planet, our solar system, and all that lies beyond.>>Good evening everybody. I’m Brian White from JPL’s Office of Communications
and Education. Welcome to the
von Karman series. Before we get started,
I want to talk about a teacher I had in college
who on the very first, great teacher, on the
very first day of class, he drew this itty-bitty tiny
little circle on the board, and he said “this is
everything you know.” [laughter] Exactly that’s what we
thought as college students. We thought we knew everything. We thought we knew more
than a tiny little circle. He says “it’s fine
because everything “that circle is
touching, is everything “you now know you don’t know.” He said “by the
end of the class,” and drew this much bigger
circle all the way around it, and he said “I hope this is you, “and I hope it’s a lot scarier, “because everything
that circle is touching “is everything you now
know you don’t know.” [laughter] Ocean worlds are a
rich and vibrant part of our solar system that
intrigue both scientists and the public alike. Obviously you’re
all here tonight. But what exactly
are we looking for, and how will we know we’ve
found it, whatever it is? Tonight we’ll take a
look at some things that we know we don’t know and
how we go about figuring out which questions to ask. Now this evening’s speaker,
Doctor Morgan Cable is a research
scientist here at JPL. While earning her PhD
in chemistry at Caltech, she designed receptor
sites for the detection of bacterial spores, the
toughest form of life. She and colleagues were the
first to discover a cocrystal, the equivalent of hydrated
mineral made exclusively of organics that may
exist on Titan’s surface. This work has led to the
inception of a new field, Titan petrology, and
she can correct me if I screwed that one up. She conducts fieldwork in
extreme environments on Earth, searching for life in places
such as the Atacama Desert, the summit of Mount Kilimanjaro and the lava fields of Iceland. She is an extreme unicyclist. She’s a surfer who worked
on the Cassini mission as a project science
systems engineer, is currently a
co-investigator on the Dragonfly mission to Titan, and a member of the
project science team for the Europa lander. Ladies and gentlemen,
Doctor Morgan Cable. [applause]>>Thank you. Can you all hear me all right? All right. Thanks so much for coming,
for braving the coronavirus. Make sure you’re all
washing your hands. We’ve been doing the
chemistry hi-five, which is with the elbow. I’ve also seen some
with the foot, you know, instead of shaking hands. It’s such a pleasure
to be here tonight. I’m so excited to
tell you a bit about the work that we’re
doing here at JPL and other NASA
centers to explore this ultimate
question, are we alone. So before we get started, I’d like you all to
do a little exercise. Now it’s kind of
late here, 7 p.m. For those of you
watching online, it might be a little bit later, but I’d like you
to take a minute to take a breath
and close your eyes. And I want you to
picture yourself, in your mind’s eye,
standing on an alien world. All right, picture it. Look up into the sky. How many suns are there? Is there a single star
like we have here, or is it more like Tatooine? Binary star systems are
actually pretty common. Maybe it’s night time. Do you see different
constellations in the sky? Look down. What are you standing on? Is it rock? Is it ice? Sand? Maybe you’re floating. Maybe it’s a boat
in your own liquid. Is that liquid water or
is it something else? Picture yourself there
on your alien world. Is there a lot of gravity? Is it larger than Earth and
so it’s pulling you down, or are you kind of floating? Would you skip around like the
astronauts did on the moon? Think about this place. And now I’m going to
give you a mission. Your mission, if you
choose to accept it, is to collect one sample. Well, not even one. Anything that your
arms can carry to prove that there is life
on your alien world. Think about what you might grab. Okay and now I’d like
you to open your eyes. This is our only example of
a place that has life, right? Our home planet. Our pale blue dot. The Earth. And you may think that in
a world teeming with life, doing that exercise
that I just asked of you would be easy, right? This would be super simple. But is it? Well it depends
on where you land. If you land here, super easy. This is the Amazon
rainforest, right? You could just go grab a leaf, maybe a monkey if
you’re quick enough. You know, you
could get something really easy and obvious
that there’s life there. Okay that’s great. But if I were an
engineer trying to design a spacecraft to land here, do
you see a safe place to land? Not so much. Chances are I would want to
land in a nice flat place. This is the Atacama
Desert in northern Chile. It’s one of the driest
deserts in the world, and we actually love
this here at NASA, because this makes an
excellent analog for Mars. A lot of the salts,
the water activity, other things about
this environment make it a good analog for Mars. But if you were to try
to look for life here, there is life here, but it’s
not quite as easy to find. You might need a
microscope for example. You might need a tool
to dig down underneath the surface a little
bit to find that life. Now what if you went
to a place like here. Does anyone recognize
the skyline? Yeah, this is Los Angeles. Now this gets into a different
kind of bio-signature, something that we call
a techno-signature, and we’re going to save that
discussion for another time. That would be amazing,
and if we find something like this somewhere checking that life box would
be pretty easy. But chances are if we were to
land anywhere here on Earth, we would land here, right? About 70% of Earth’s
surface is covered in water. And if you were to design
a container to collect life to bring back, you would
design it differently if you were going to land
someplace like an ocean then you would if
you were landing in a desert or in a rainforest, and so depending on where you go and what you’re looking
for, may define the type of things that you would bring
with you to your alien world. And it’s appropriate
that we end on water, because for NASA this is
one of the key ingredients that we look for when
we’re searching for life. It’s not the only thing. Of course there could be life
that is not aqueous based, that’s not based
on liquid water. But this is our
sample size, right? Sample size of one. One world and here we find that life needs three
key ingredients. One of them is liquid water. Liquid helps you
transport nutrients in, transport waste out. It gives, it sort of greases the molecular machinery
of life it lubricates it. So we know that
life needs water. We also know that it needs
what I call chemistry. Basically building blocks. You need something to
make those molecules that you are made up of. You need something
to make those out of, and that can be carbon,
hydrogen, nitrogen, like we have here abundantly. Typically it’ll be something
that’s pretty common. If we were all based on, I
don’t know, titanium or iridium, there’s not a lot
of that around, so there wouldn’t
be very many of us. Which I guess means
we wouldn’t have as many coronavirus distributor,
which would be good. But you typically use building
blocks that are common. So that’s the second thing. We need the building
blocks of life. And the third thing
we need is energy. Something to metabolize. Something to drive the
chemical reactions, the biochemical reactions
that keep us alive. And so any place on
Earth where we find those three things,
we find life. Every time. And so these are the things
that we will look for when we try to explore our
solar system and beyond and search for life there. So let’s go a little bit
further out from Earth, we’re going to go about 480
million miles to Jupiter. Jupiter’s our largest planet
in our solar system, right? It’s kind of the bouncer. It sorta kept a lot of
major meteoritic events from happening here on
Earth, at least not too many. So we’re 65 million years and
counting since the last one. That’s great. Jupiter is amazing. It’s beautiful and I love it. But I love its moons even more. Jupiter has four what
we call Galilean moons, ’cause Galileo discovered them, should get some credit. And three of them are locked in what’s called
the tidal resonance. And this one, Europa,
is in the middle. So in between Europa and
Jupiter is a world called Io. It’s the most volcanically
active body in the solar system. It’s a really cool place
and it’s really hot because of its interaction with
Europa and also with the third moon out which
is called Ganymede. So it goes Io, Europa, Ganymede. And for every one orbit
Europa does, Io does two. For every orbit that Ganymede
does, Europa does two. And so what happens
is, it’s kind of like, you remember on the playground
when you were a kid, if you pushed your friend
or maybe your sister, brother on the swing set, and you wanted them
to go really high, you had to time that pushes
just right, you know, and if you did that you could
get them go maybe higher than your parents
thought was safe. That’s what’s happening
here with these worlds. So they’re locked in this
gravitational tug-of-war and because of this resonance, every time they orbit
around they give each other this energetic kick. And here that kick turns into
this friction that causes the worlds to move like this. And so that flexing
we call tidal flexing, that generates heat. And that’s why Europa has a lot of liquid underneath
this icy shell. And it’s why it’s one
of my favorite places in the entire solar system. Europa actually has two to
three times the volume of all of Earth’s oceans
combined in liquid water. That’s a lot of water. Now it’s under a shell of ice. But it’s really interesting
because you can learn a lot about this
world, we think, from studying Europa’s surface. Now you may notice that
it’s got some cracks and some grooves and they
seem to be a darker color. We’re not sure exactly
what that dark color is, we think it could either be
salts or organic molecules, maybe a little bit of both. But one thing is kind
of missing from this. Does anyone know? I’ll give you a hint, our
moon has a lot of these. Yes. Craters. Turns out Europa
only has this many. It’s got about
seven big craters. You know that’s important, because this is
how we date objects in our solar system,
by crater counting. And this tells us
that the surface of Europa is relatively young. Now this is cool. It’s about 50 million years. So even younger
than the dinosaurs, which means something must
be refreshing it somehow. We think that there could be
some activity from the ocean, maybe some localized heating. We see these things
called lenticulae, which is Greek or
Latin for freckles. Some places where it looks
like there’re little hot spots. We see these smooth bands
where it looks like some of the surface has split open
and water has been sucked up or ice has been sucked up
and filled in the gaps. And so we see these
places on the surface where it looks like
there’s a lot of activity, and that gets us really excited, because we would want, if we send something
to explore this place, to search those fresher regions. Those may have more
organics in them, they may have better evidence of what’s in that
ocean underneath. And boy, wouldn’t it be great
to send a spacecraft here and look for life or look
for evidence of habitability? Yes it would. And we’re going to do that. Europa is incredible, right? We think that underneath
this ice shell, we know that it has
a liquid water ocean, we’re not sure exactly
how deep it is. That’s one of the things that our next mission
is going to study. But we do know that there’s a lot of radiation
at the surface. This is because
Jupiter is really big. It acts as the bouncer for
the rest of our solar system, which is great, but it also
has some negative effects for some of the moons around it. Because it’s so large
it sucks in a lot of the charged particles
from the solar winds and it whips them around with its really strong
magnetic field, and it slams them into Europa. Now Europa doesn’t
have an atmosphere, and so these things
will interact directly with that water
ice on the surface. And water ice is H2O right? That’s water. It’ll break that up. It’ll kick off the hydrogens and since they’re super
light they float away, and so you’ll end up
with this tenuous oxygen, we don’t even call
it an atmosphere. We call it in exosphere
’cause it’s so thin. And that oxygen is
really rich in electrons. Now down at the
seafloor where we think there could be hydrothermal
activity, heating, geothermal activity,
things like that, we are pretty sure based
on examples here on Earth that that place
is electron poor. So if you’ve got a lot of
electrons in one place, a few electrons in another
place, you know what that is? That’s a battery,
basically right? You just need to connect the
two and there’s a lot of types of life here on Earth
that we call a chemotroph. Chemoautotrophs. Chemo- means chemistry, auto means it does it by
itself, it doesn’t need help, and it uses those types
of energy sources, just shuttling the
electrons around. Takes a little tax, a
little bit off the top, and that’s what it
uses to be alive. And so there are all
sorts of organisms that could exist in
environments like this. And the Europa Clipper Mission
is going to study this world. So Europa Clipper is a mission that NASA’s building right now. It’s going to have nine
different instruments that will be able
to study Europa, its surface, its interior, and all of these properties
to help us understand whether or not it’s
habitable and whether or not there could be life there
today, or maybe in the past. Europa Clipper is
going to be ready for launch in about 2025, as
I said we’re building it now. And depending on
which rocket we go on, we’ll reach the Jupiter system
maybe sixish years later, and we’ll bring all of
these instruments to bear. We’re going to have some
very sensitive cameras that will be able
to take incredibly high resolution images
of Europa’s surface. We will have basically
a fancy compass, magnetometer that can
tell us by studying the magnetic field properties
of that ocean and its depth. We’ll have a radar
sounder that could do the same thing we do
here when we fly radar over Antarctica to get at
the thickness of the ice and if there are any
pockets of water in there. It will also have an instrument
called a mass spectrometer. And we actually have
two different kinds. One that can get at the gas. It’s sort of like your nose. It’ll sniff what’s there. Things that are coming
off the surface, to tell us if there are
any interesting gases like hydrogen or methane, things that we could tie to some sort of
geothermal activity. And we’ll also have
one that it’s kind of like sticking out your
tongue and tasting snowflakes, except doing it, you know,
five kilometers a second. Would not recommend doing
that with your tongue, but with the instrument
aboard that’s a dust detector, that is actually the perfect
speed to pick up dust grains, ice grains, you smash them
open and you can determine what kind of organic
molecules are present. And so we can do
that for bits of ice that are sputtered
off the surface from micrometeoroid impacts
and things like that, and get an idea what that
surface composition is, even without landing. So the Europa Clipper
Mission is going to be in the Jupiter system
for several years, but we decided to not
have it orbit Europa because of the
intense radiation. It’s not so good for us
if we were standing on the surface of Europa,
you probably get a lethal dose of
radiation in a few hours, it’s not good for
spacecraft either. It can cause things
like single-event upsets in your electronics
and make them function, turn on and off in ways
that you don’t expect. And so what Europa
Clipper’s going to do is it’s going to
get close to Europa, take lots of data and
then come back out, cool off, send the data
back give us some time to interpret it,
think about it before it goes back in again
for its next pass. And this is something that
we’re really excited about, because we’ll be able
to get images that every time we send a powerful
spacecraft somewhere, and we bring advanced
instruments like cameras, detectors, the electronic
tongue I was talking about, we always find things
that surprise us. And I can’t imagine the
things that we will find here that will surprise us. Now when NASA does missions,
typically we like to send an orbiter or a
flyby mission first. Now there’s some
reasons for that. This can give us a
lot of great images and maps of the surface. One of the other
instruments aboard Clipper is basically like a
really fancy camera. For every picture that
it takes, each pixel of that image will
actually be a spectrum. That will give us
information about what the surface is made of. Those kinds of details
are really important, ’cause ultimately
if we want to answer the life question,
we need to land, and we’re working
right now on a concept. This is called
the Europa Lander. This is something that
would come after Clipper and be able to take
all of that information to help us pick just the
right spot to land, right? We want to go to a safe place
but an interesting place that could potentially
have signatures of life. It will have the ability
to communicate directly with Earth through
its high gain antenna, and it will have
an arm, it would, that would be able to
cut into the surface. Now the surface of
Europa is pretty cold. It’s about a hundred
and fifty Kelvin. Which, let’s see in celsius
that’s what -130 degrees C. I don’t know what it is in
fahrenheit I’m a scientist. We don’t work in fahrenheit. But it’s really cold. And it turns out that
ice at those temperatures has a lot of similar properties
to rock, like granite. And some of our
engineers here at JPL who are designing types of
cutting tools to be able to slice into that
really hard ice, boy they are really interesting. One of the guys was telling me “yeah I was on my
treadmill this morning, “I was thinking about what
is the toughest sample “that we could come up with.” And he ended up,
this was really mean. He took cotton, and he
stretched out the cotton balls until you get like that
really fibrous kind of stuff, and then he put
that in water ice, and then dunked that
and liquid nitrogen. And he said that broke about
half of their prototypes, because of the fibers, you
know, tripped up all the blades. But the reason that we do that
is because we want to be sure that we have
over-engineered everything, such that even if the
surface is something we wouldn’t necessarily expect, we can still do our science. Even if we land in a place
where there’s something, there’re bigger rocks
than we expected, there might be some
weird fibrous things, that we could still cut
some of that sample, hopefully not destroy some
really sensitive organism, and bring it in and look
at it with our instruments. And so that’s what this
type of mission concept would be able to do. So Europa is a
fascinating place. But it’s not the only place. There are a few
other worlds I’d like to tell you about tonight. So let’s go a
little bit further, actually a lot further, out
further away from the sun. So you know how you’ve got
those like nice diagrams of the solar system and it
shows like the sun and then Mercury, Venus and they’re
all kind of evenly spaced out. You know they’re not
actually like that, right? Like the distance from
the sun to Jupiter, you’ve got to do that
again to get to Saturn. Space is big, okay. So if you’re here at
Saturn now, the sun is, it’s not 10 times dimmer. The distance is 10 times, but the light intensity varies, do you guys remember this
from from high school? One over R squared. 100 times dimmer, right? Because it’s 10 squared. So things are very
different around Saturn. We were fortunate to
have a spacecraft in the Saturn system
called Cassini, which if you’re here in the room is right over there,
the scale model. Cassini launched
in, let’s see, ’97, it arrived in the
Saturn system in 2004. Space is big. And was there for
about 13 years. And I was lucky enough
to be involved in the Cassini mission
right near the end of its time in
the Saturn system. We learned so much about Saturn,
its rings, and its moons. And one of the ones
that surprised us the
most was this one. This is one of my
favorite places. This is Enceladus. Small things can
be mighty, I know. Enceladus is relatively small. It’s about the size of Arizona. But really amazing things are
packed in this tiny package. It is the whitest and brightest
body in the solar system, which tells us that the surface is mostly just really
reflective snow, water ice. And you see that cool thing
spewing out of the south pole? Yes, that is a plume and
that surprised all of us. When we built Cassini,
we didn’t think there was liquid water out this far. So we cleaned it but
we didn’t sterilize it. That’s actually why
Cassini ended up doing its swan dive into
Saturn when we reached the end of the
spacecraft’s life, ’cause we didn’t want to
contaminate places like this. Enceladus, in its south pole,
has these four big cracks. They’re called tiger stripes, ’cause it looks like a giant
tiger just went like that. But these are really
big, it’d have to be a very large tiger there about, let’s see, three marathons long. A marathon’s what’s
42 kilometers? 42, answer to everything. Yes. And they’re a
little bit less than a marathon in
between each of them. So these are really
large cracks, and coming out from
them is a lot of water. It starts out as
liquid, this has a liquid water ocean
just like Europa, and when that water comes
out into space it freezes, and then it can reflect
light beautifully from the sun which are what some of these gorgeous back-lit
or front-lit images are. And it’s spewing out
tons of just free sample from its ocean into space. No need to dig or drill, just like “NASA, you want
to find life somewhere? “Come on down, get your
free sample right here.” Now when we built Cassini,
we didn’t think there was liquid water out this far, and we sure didn’t
think that there could be life this far out, and so Cassini did not have
life detection instruments on board, but it was
still able to fly through this plume multiple times
and use its instruments to give us some hints of
what we think is there. Just like Europa Clipper,
Cassini also had that tongue that could stick out and
collect some ice grains and figure out if there are
organic molecules there, and it found some. It had a sniffing instrument
so we could sniff gases, and it found
hydrogen and methane, two things that we
know organisms either
eat or poop out. Either way it’s exciting
that they’re there, and it also found evidence
of hydrothermal vents, like we think are also
present on Europa. We found three separate
lines of evidence that tell us there could
be places at the seafloor where water from the
ocean goes underneath, gets heated up and
then comes back out. Now this is a video of a
hydrothermal vent here on Earth. I would love if this
was taken at Enceladus, we’re not quite there yet
but we’re working on it. These places are very
rich ecosystems of life. Not just bacteria,
but crabs octopus, octopods I think is a plural
officially of octopus, we see tubeworms, all sorts
of advanced organisms. And their living as far
removed from sunlight as you can get here on Earth. Now this is important, right? ‘Cause all of these ocean
worlds I’m showing you have a thick layer of
ice that’s shielding that ocean from sunlight. Almost all life here on
Earth needs sunlight, directly or indirectly. If you are a plant, it’s direct. If you eat a plant,
it’s indirect. And so we seek evidence
in communities like this, these rare places where sunlight
doesn’t seem to be needed, to give us clues to what we
might look for in these worlds. And so a lot of NASA
scientists will study these hydrothermal
systems here on Earth, or ask our oceanographer
buddies to give us some hints and some clues as to
what we might look for and where we might
get tripped up if we’re trying to design an
experiment to look for life. So Enceladus is another
fascinating place. But I want to tell
you about one more. This is one of the bigger
moons in our solar system. It looks tiny next to Saturn, you see that little
sorta golden dot. That’s Titan. Titan is the second largest
moon in our solar system. If you count its atmosphere,
it’s actually the biggest. But we’ll give Ganymede a win, ’cause otherwise it’s
not quite as fascinating. Titan has an atmosphere, an atmosphere that’s actually
thicker than Earth’s. And thanks to a
collaboration between NASA and the European
Space Agency, the ESA, we were able to land
the Huygens probe on the surface of Titan, and this
is the image that it took. Now it kind of looks
like Earth, right? You see some dirt there, it’s probably a really
hazy day here in LA, right? It’s kinda yellowish brown. And you see some pebbles
there, some rocks. Those are not rocks
as we know it. Those we think are
made out of water ice, and that brown stuff
we think is a mixture of complex organic molecules that are made in the atmosphere. Actually similar to smog. We think it’s photochemistry, it’s the same way smog is made. So light interacts
with some gases, those gases start to
link their atoms together to make bigger molecules,
and those continue, those reactions
continue to happen and you get bigger
and bigger aerosols that eventually get big enough that they rain down or
snow down on the surface. We think that’s
what’s happening. But there’s still
a lot of unanswered
questions about Titan. One of the coolest
things about Titan is that it’s not just rocks,
it’s not just, you know, it has clouds, it
has an atmosphere, but it also has
liquid on its surface. Titan is even colder
than Europa though. Its -183 degrees C,
which is 90 kelvin and I don’t know what
that is in fahrenheit, but it’s even colder. However if you were standing
on the surface of Titan, you would not actually need a spacesuit because
of that atmosphere. You’d need a heck of a parka. Like a really thick one. You know frostbite
would be a thing. But you could walk
around without that pressurized spacesuit. This is, the pressure is
about one and a half times our pressure here on
Earth at sea level. And so because of that, a lot of really cool
things are possible. We also see rain
happening on Titan, but because it’s so cold
it’s not liquid water. Water is frozen solid. We see lakes that are made
out of liquid hydrocarbons. Methane and ethane. When I give talks to kids, I say liquid farts and they
all get really excited. Sometimes adults do too. [laughter] I love it. It’s great. But this is fascinating, right? Because if you remember
from like maybe middle or high school chemistry, water is a polar solvent, right? Methane and ethane
are the opposite. They are nonpolar. And you may recall
like dissolves like. Anything that dissolves in
liquid water is not going to in these liquid
hydrocarbons, and vice versa. And so we have these huge
seas, they’re as big as the Great Lakes, and bigger, that are filled with this
liquid that couldn’t be, it could not grease the
machinery of life as we know it. But it could potentially do that for some other weird alien
chemistry that would have to be by definition very different
from any biochemistry here on Earth just to be
able to stay dissolved and work in a liquid like this. So just in our own
cosmic backyard, we have this wild
example of something that boy would be really
nice if we could go here and study this world more. So it’s got this cool
stuff on its surface, but people always forget
this Titan also has a liquid water
ocean underneath all of the cool stuff
happening on the surface. You got those liquid
hydrocarbon lakes, that cool organicy stuff that
we don’t know what it is, and then you go down through
the ice, which is the shell, and you hit liquid water also. Now this is really
exciting to me, for someone who is a
chemist by training, I study organic chemistry
because we’ve tried to replicate some places
in Titans environment, here in the laboratory. We can do that
same photochemistry that makes that gunk
in the atmosphere. Carl Sagan was actually
one of the first people to do this in the lab
and he named that stuff, he called it tholin, which is
from the Greek word tholos, which means muddy or not clear. Which is really great
it’s a double meaning. Because the stuff,
when you make it, it’s like that brownish
orangeish color, so it’s sort of mud colored. And we also don’t know
what it’s made of. ‘Cause you stick it
into an instrument, and you get this
forest of peaks. It’s like anything
that you can think of that’s made out of carbon,
hydrogen and nitrogen. Those three elements, you mix
’em together whatever way, do you have your chemistry
set at home, anybody? I do. No, you don’t do that for fun? But you can make small
things, big things, every, it’s all in there,
in the tholin, and the really cool thing
is if you take that tholin and you dissolve
it in liquid water, you make amino acids, like that. So if any of that organicy
goopy stuff that’s made on, in the atmosphere that
stuck on the surface, if any of that gets pulled down into that liquid water ocean, boy you’ve got a lot of
interesting molecules now that life could use potentially. And so this is why
I think Titan is a really fascinating
world, worthy of study. Boy, wouldn’t it be great
if we were working on a mission to go there? We are. This is Dragonfly. This is a brand new mission, it was just selected in July
of last year, and it is big. This is eight-bladed
rotorcraft that can move, remember I said the
atmosphere is thick? The gravity on
Titan is a lot less. It turns out it’s more
efficient to fly around than it would be to drive, like our typical
rovers do on Mars. And this thing is large. Like our first
science team meeting, they had the VR headset so
we can see how big it is, and like okay, I’m not
normal-sized human, so picture little
bit bigger than me, but it’s like I put out my arms and I can’t quite reach as wide. Like it’s big. That antenna, the
direct to Earth antenna, that thing that folds up in
back, is like taller than me, I was looking up at it. This thing is big. But because of all
the advancements in rotorcraft technology,
in autonomous navigation, this type of thing is
possible to do now, which is super exciting, ’cause this means we
can land in one spot, study that place
and then pick up and go somewhere
else interesting. So we can study these
dunes that we see in the equatorial region of Titan, that’s where we’re
going to start. We’re going to
start near a crater. Titan also doesn’t
have very many craters, but it’s got a few, and it’s a great place
’cause it looks like that impact excavated
some stuff out and some of the water ice may be
really accessible, and so we’re gonna go there too, and we’re going to just
hop around for a few years. This is going to
launch we hope in 2026, land on Titan in 2034. Space is big. And don’t count how
old you will be, because you might get depressed, but I’m really excited
about this mission. So the future is really
bright when it comes to the types of missions
that we’re working on, that we’re building
to answer some of these critical questions
about ocean worlds and whether or not we’re alone. But this is just in our
own cosmic backyard. What about further than that? I’d like to introduce you
to the TRAPPIST system. So this is about
12 parsecs out in the Aquarius
constellation, so if you’re a really good pilot
like Han Solo, this is one Kessel Run away. [laughter] I’m glad you went
with me on that one. It’s got about seven planets in orbit around
a red dwarf star. Now this is a place that we
are just starting to study, but there are a handful of
worlds even in this system that are in what we
call the habitable zone. Now what is that? Well that’s where Earth is. If you’re too close
to your host star, things get a little bit
hot and liquid water is not stable at the surface,
it would all boil away. If you’re too far
you end up with the opposite problem, right? Things get frozen solid. Earth is in just that
right happy place, where liquid water can
be stable on the surface, and when we look at exoplanets, that’s what we
call these planets in orbit around other stars, We start off looking
in that habitable zone, because those worlds
may be similar to Earth. And we’ve started a
catalog and just in a few years of looking
we’ve already found a bunch. You can see some
that say TRAPPIST-1, whatever there’s a
letter at the end, that’s typically how
we name exoplanets. We start with the
telescope that found them, so the TRAPPIST, or the mission
that found them is first, then we give it a number for
the star that we observed, and then the planets all
get letters, so A-B-C-D-E, so you can figure
out where it is, how close it is
to its host star. And so you can see
TRAPPIST D, E and F and G all seem to be in
that habitable zone, and that’s just around one star, and we’ve just started looking. This thing is probably
already out of date, it’s from September of last year but I’m sure we
found a few more. And this just blows
your mind, right? These are just the ones
in the habitable system. We haven’t even started
looking for exo-Europas and exo-Titans and exo-Enceladi? Enceladi. Now we know that liquid water
can exist even further out than this habitable zone
that Earth resides in. It’s an incredibly
exciting time to be a planetary scientist, to
be studying these worlds. But looking for life on a place this far away is
challenging, right? If we wanted to send
a spacecraft there, it would take a very long time. We’re working on
concepts like that. There’s some spacecraft
that we’re working on using things like
solar electric propulsion or even lasers to
accelerate them to a significant percentage
of the speed of light, which is nuts, ’cause
then how do you slow down. But we’re working on that, too. And to get to these world
so that we can study them. We can still do a lot with powerful telescopes
here on Earth. One of the nice things
we can do is if some of these worlds are
just the right angle where they pass between
us and their host star, we can do spectroscopy. Spectro- is lights,
-scopy is study, so we’re studying
light, spectroscopy. So we can break that
down into the rainbow and look at what
wavelengths are missing, and by doing that we can tell
what kind of gases are in the atmospheres of
some of these worlds, which is pretty amazing. But the search for life
can have challenges, right? It can be tough. Who recognizes this image? Yeah, this is, does anyone
know the name of the meteorite? Very good, it’s ALH84001. Which do you want to know
how meteorites are named? I’m going to tell you. Guess what. All right so this was a Mars
meteorite that was discovered in Allan Hills Antarctica,
that’s where the ALH comes for, the 84 is from 1984,
’cause that was the year that it was discovered,
and then the 001 is it was the first meteorite that was
found that year in this place. They leave a couple
extra digits, ’cause I guess they’re hoping
they’ll find, you know, maybe 100 or more,
that would be great. We haven’t found that many
Mars meteorites though. We found about 30 so far, and most of them we
do find in Antarctica, because it’s nice and white, there’s not a lot of snow
or anything else happening, and so these black meteorites
show up brilliantly. They’re very easy to find. So this one ALH84001 is the oldest Mars meteorite
that we’ve found. We think that it’s from
a time in Mars’s history when it was much
warmer and wetter. Now the reason we know
it’s from Mars is because there were some
trapped gases inside that we were able to
sample, and those gases are the same as in
Mars’s atmosphere. We also some other
evidence to show us, to prove to ourselves
as scientists that
this is from Mars. And when we sliced it open
and looked at it under a scanning electron microscope,
this is what we saw. And of course we all immediately
got very excited, right? Because that thing
looks like a worm. Well it’s not. It’s about 1/100 the
width of a human hair, which is incredibly small, very few cells are
even that small, much less a multicellular
organism like this. But it gives us some
lessons as to when life can, or when evidence that we
think as biased humans that we see looks like life, whether or not it is
actually life or not. So we study the chemical
signatures that were in this meteorite and there
is still to this day, some scientists, a small
subset of the community that are convinced that this
is actually evidence of life. But the problem is it’s hard
to convince the rest of us, and the reason for
that is because there are abiotic
explanations for all of the things that we see here. We see some carbonate globules. Carbonate typically is
associated with life, especially fossilized life, but you can also make
it without life, too. We see magnetite crystals
inside of this meteorite. Now some bacteria will
actually use magnetite, kind of like little compasses
to sort of navigate around, but the amount of
magnetite that we saw was inconsistent with what we would expect
for most organisms. The amount that we
saw would have meant that Mars’s magnetic field
would be super strong, like way stronger than Earth’s, and that’s doesn’t make
sense ’cause it’s smaller, how could it, that
doesn’t make sense. And you can also deposit
that abiotically, too. So Carl Sagan said once that “life has to be the
hypothesis of last resort.” You must have eliminated all
other possible explanations, and if you can do that and the
only thing you’re left with is life then you
can be convinced. And the problem with this
meteorite is there are still enough abiotic
explanations for this that all of us
can’t be convinced. And this is something that
we have here, on Earth. So we can bring to bear all of our most sensitive
instruments, some of the microscopes
and spectrometers that fill a room, right? What if you want to take
that and now put it on a spacecraft, miniaturize it and then send it somewhere else? Some of the instrumentation,
it gets challenging, right? You may not be able
to be as sensitive, but now you can be sure that
you know exactly what happened to your sample in between
when it was there on Mars, for example like with Viking, and when you reached
out your robotic arm and grabbed it and then
looked at what was inside. With meteorites we can
guess at when they formed, that meteorite that
I was showing you, it probably was ejected
from Mars millions, maybe billions of years ago,
when it was warmer and wetter, and then it just kind of
circled around in space for a while we think until
about 16,000 years ago. And that’s when it
crashed here on Earth. We don’t really know what
was happening to it during that time and that
uncertainty can lead us to question anything we
might find inside it. That’s why we want to go
and land on these places, where we have a
better understanding of what we call the
provenance of that sample, the history, where it’s
been, how it got there, so that if we find
a signature in it we can say for sure that
came from this place, it’s not contamination. It’s not something
it picked up later. That’s really important
for being sure when we finally answer this
key question are we alone, we can be sure of our answer. So the Viking landers, there were two of
them in the 1970s. These landed on the
surface of Mars, and this was the first
mission that explicitly had the goal of looking for
life somewhere else. On Mars in this case. The Viking landers, they
had identical instruments and they went to two different
places on Mars’s surface, and they had three biology
detection instruments. They also had a
chemical analyzer called a mass spectrometer,
remember the tongue, it’s like similar to that. Of the three
biology experiments, one gave a positive
result for life, one was negative and
one was ambiguous. Now this isn’t because the
scientists did a poor job, they did the best job
that they could designing an experiment that they
thought would give them that absolute yes or no answer. But all three of
these techniques were based off of
metabolic assays. Basically what they did is
they scooped up some Mars soil, some Mars regolith,
they put it in a bin and then they dropped
either water or liquid water or some nutrients on it
or both and sealed it up and they looked at the gases
that came off or they looked at whether or not it could
take some of the nutrients that it was given and be
able to turn that into other molecules that could
give us evidence of life. So these tests were
based off of them going to different places
here on Earth and trying those
same experiments, and they thought that they
were very confident that these types of
things could give us an absolute yes or no
answer, are we alone. Well it turns out that
we didn’t have as deep of a knowledge of the surface
chemistry of Mars at that time. Since then we’ve
discovered that there are things like perchlorates,
very reactive salts, that can give the
same types of answers. It turns out that a
scientist recently was able to replicate very
well, not perfectly, but really closely those
same false positives, what we call it, when
you see something that you think is
real but its not. Those false positive
measurements, if you take perchlorate
and you sort of give it a light dusting of gamma rays, and then you do that same sort of life
detection measurement, you dump some water and
some nutrients on it, you’d get the same gases off. And so, as Carl
said, life has to be that hypothesis of last resort, and in the case of the
Viking experiments, we still have abiotic
explanations that could explain the data that we see. But we have learned
a lot since then. When we were building and
launching the Viking landers, we didn’t know about the
third branch of life. We knew about
bacteria and fungi, but we didn’t know
about archaea. That haven’t been
discovered yet. We know a lot more
now than we did then. It doesn’t mean though that
we won’t make new mistakes whenever we search
for life elsewhere. And that’s something
that as scientists we always need to keep in mind. We will do our best to design the most foolproof experiments. But we have to prepare
ourselves for the fact that we will likely make
new and different mistakes. We’ll still learn something,
and we still have to go. Because we need to know. But we need to make sure that
we’re prepared for an answer. And so that’s something
that I always try to keep in mind
when we’re having these endless discussions
about what experiments we should do, how
sure we can be, how many tests we can
do here to be positive that we’re spending
our taxpayer dollars, your dollars, as well
as we can, right? Because that’s what NASA does. And we can take a
lot of lessons from the types of life that
we have here on Earth. Does anyone recognize
this little guy? The tardigrade. The water bear. This little guy can
survive in space, right? I think he’s super cute. One of my friends said
“boy, it would be terrifying “if that was like
large enough to ride.” I think that’d be amazing. Could you imagine
like riding around. It’s be awesome. So we have examples of life that can survive really
extreme conditions. How would you look
for a tardigrade? Would a microscope be enough? That would just be a
morphology type of measurement. What if you saw it move? That would be better. Maybe if you also were
able to study some of the molecules that
the tardigrade is
consuming or producing, or maybe sad to
say, maybe just take the tardigrade itself
and stick it into an instrument and see
what it’s made of. These are types of
things that we could do if we expect this kind of life. But we see some other
weird things too. This kind of organism, I
can’t remember its name, but it doesn’t need oxygen. It’s one of the few animals,
even though it’s microscopic, it’s an animal that doesn’t
need oxygen to be alive. This is a brand-new sea
slug that’s new to science, discovered just last year. So we’re still finding even
on our own planet all sorts of wacky and wild forms of
what look like alien life, and this guy, this
is something we call the immortal jellyfish. It’s about the size
of your pinky nail, and it does this weird thing. When conditions get bad,
it reverts back to its sort of primordial polyp form and
it just kind of chills out, and then again when
conditions get good again, it makes itself back
into a jellyfish. So we think this thing
could potentially live for a really long time,
maybe forever. Forever is a long time, but
at least for a very long time. So we try to take lessons
from the extreme forms of life that we see here
to help inform those tests that we might perform
somewhere else, to answer that pivotal question. ‘Cause this is what
we’re going for, right? At least, you know,
it’d be great, to write my speech, to go in
and collect the Nobel Prize for finding life for the
first time in human history. This is something we call
civilization level science. You only get to make
this discovery once, and it would
revolutionize, I think, our opinion of who
we are as a species. Whether or not we’re alone. Is the Earth just this this
precious terribly alone ball, or is it one of millions and
billions that are out there, that could potentially all
have different various forms of life that we
couldn’t even imagine? This kind, we have the
technology to answer this question now, and
we’re building missions to go and find these answers. It’s an incredibly exciting
time to work for NASA, to be a planetary scientist,
and I don’t even need that. I would just be so happy to
be part of this question, of trying to find the answer. But there is that
other potential, that maybe we
search for life here in our own cosmic
backyard and elsewhere and we come up empty. Do you recognize this image? This is the 30-year
anniversary, actually, of the pale blue dot, which was taken by
Voyager One spacecraft, the last von Karman
lecture I believe focused heavily on this. What if this is all there is? I find that terrifying,
but in a way it could also be really gratifying to think
that we are this precious. That this world
just happened to be the magical place
where life can happen, and boy it really
makes you think about how we want to preserve
that and keep it going, maybe go over to Mars and you
know, set up a colony there, just in case the next
65 million year meteor. We don’t want that to happen. But that would be a
revolutionary discovery, too. And either way as a
scientist, I want to know. I want to ask the question. I want to design that
experiment or help to design that experiment
where we end up with that single hypothesis
of last resort, that the only explanation
could be life. it could not be
made abiotically. And then I want to go and
figure out what that life is. Right now we only have
a sample size of one. That’s it, right? This could be all there is, or it could be one
small grain of sand in an immense universe of worlds that could all have
life of their own. I want to be part of
finding that answer. So I want you to go back
now, close your eyes again. I know it’s like 45 minutes
later, but you can do it. I believe in you. I haven’t heard any snoring
yet, you guys have done so well. And go back to that
alien world again. Except this time it’s
not you standing there, it’s a robotic version of you. It’s a robotic
exploration spacecraft. So now when you look up at
that sun or those suns in the sky, it’s not just a light
that you see now you have a spectrometer, and you
can break down that light and figure out what
that energy profile is and how that light
might be utilized by life that’s on your world. Now whenever you look down, you can figure out what
the rock distribution is, and which one is most
likely to have maybe a microbe hiding underneath it. Now you have instruments
inside of you and your belly that when you take a sample
and you put it in there, you can be sure that that
has the signatures of life. For the first time
in human history of an alien somewhere else. That’s what we do at NASA. That’s what I’m helping to
work on with my colleagues, is to be able to extend
our senses further out into the solar system and beyond. I want to be able
to take that circle and expand it out further
than I can possibly imagine, to stretch it out
as far as I can during my time here as a human and that’s just why I
love terribly what I do. Thank you very much. [applause]>>Folks, we are
going to open up for some questions right now. If you are in the house
and you’ve got a question, you’re going to
line up right behind that microphone over there. We also have some questions from our online audience as well. So while you’re all
thinking about maybe a question you’re going to ask, I’m going to go online here to the great Mosasaur
from YouTube asks “although there isn’t a
concrete answer for this, “in your opinion, your opinion, “do you think we can find
life on these worlds? “Can we expect to see
it in our lifetime?”>>I think so, otherwise I would be spending my energy
doing something else. Again with just the
sample size of one, we have some guesstimates of the types of life we would find, chances are they’re going
to be small microorganisms, just based on the
energy that’s there, and we have some estimates of how many organisms we might
expect in some of these oceans. So we have some idea
of the types of life and the amounts of
life we might find, and some of the instruments
that we are working on miniaturizing and sticking
on spacecraft right now have limits of detection
that are sensitive enough that they could
find those things. That’s why I think that
we have the ability to answer this question now.>>Another one from
online, from Space Debris on YouTube, it’s kind of similar to what you were just answering and what the last part of
what you were talking about, “besides knowing
we’re not alone, “what is the best
value for humans “in finding life
on another world?”>>For me it’s
knowing that there are so many other
possibilities out there. I mean if we’re not asking
these big questions, the things that when we were
much earlier on in our history of just starting to be
humans and we looked up from that campfire up into
the stars at night and wondered about them. That’s what sets
us apart, right? Otherwise we’re just what, like eat, sleep, reproduce
and die and that’s it? You know? This is the thing
that drives us, that makes us human is to
ask these questions why, and because of that we want
to strive to know the answers. And as soon as we know the
answer to that question, we’re going to
have so many more. It’s going to be this
amazing beautiful cycle and I want to kick
off some more of that.>>I think we’ve got a
question here in the house.>>This is a very very
interesting lecture. I really like it. So you talked about the the
nonpolar versus the polar and how if those mix I
guess it was on Europa?>>Titan.>>It was on Titan that we mix. Because there’s what
is actually water under Titan even though. So my question is, so you
have all this carbon on Titan, why, do we have any idea
why we have a planet, satellite at Saturn
that’s heavily carbon, and then we have Io at
Jupiter that’s heavily sulfur. Why do we have, why don’t
we have one of each on both, circling both
Jupiter and Saturn?>>That’s a great question. Well a lot of these
worlds probably do have a lot of
carbon and sulfur, but it may be in different forms where it’s trapped in the crust
or underneath the ice shell. Titan we’re lucky,
because of its atmosphere. It’s outgassing methane
from its interior. We’re actually not sure
why it’s still doing that, because if you
look at the amount of methane that should be there, it should have run
out in oh, you know, a hundred million years. So there’s probably some
funky cycle that’s going on and we’re catching
it at a good time. But that methane is
what’s broken up by light. Methane and nitrogen. So we’ve got CH4 and N2, and you break those apart
and you make all sorts of other different
C, H, N things, and that’s what the
photo chemistry is making that’s depositing
on the surface. There are other worlds where
you still have reservoirs of carbon maybe as methane ice, like Pluto is very rich in
methane ice for an example. As you step further
into the solar system, closer to the sun you don’t
have as many volatiles. Those, the things
that are gases here freeze out as ices further out, but you have other
complex organic molecules. Like we have here on Earth. A lot of the organics
that are here probably were deposited by comets and meteoritic impacts
over a millennia, and so that’s another
great source of carbon.>>Audience Member: Thank you.>>All right and this will be
our last question in the house. If we don’t get a chance
to ask your question, Morgan is going to
stick around for awhile, answer, she said she’ll
answer everything that comes up here. So good luck to that. But our last question in here.>>Yes. What promising technologies
do we have at this point for getting through
the layers of ice into the oceans of
these water worlds?>>Okay. I could do a whole
other talk just on that. So there are a few
different architectures that NASA scientists and
a bunch of engineers both at NASA centers and universities and other companies
are working on. There’s one that we
call it a melt probe, it’s something that
would have a heated tip, there are a bunch of different
ways you can do that, that would slowly melt away or sublime if you’re
in a vacuum, right? The solid would just turn
into water vapor and go away. You can use that to get down. There are also some
robotic techniques. There’s a concept that
I’m working on with some colleagues here
at JPL called EELS, Enceladus Extant Life Surveyor, it also is like snake
like, so eels, get it. We love acronyms if
you haven’t noticed. That could maneuver down
through those open tiger stripes on Enceladus, and potentially
reach the ocean that way, and so there are a bunch
of different things we’re working on, ’cause
getting to that ocean would be the ideal place
to look for life, ’cause then you could
take in your sensor and you could just
filter water for as long as you wanted until you got
the concentrations high enough to be sure that if there
was even one cell in like, you know, gallons
and gallons of water, that you would find it.>>And how would we get the
information back from the probe?>>How would we get
the information back? So there are some
theories about that. You could have a tether, but if there are some
geophysical tidal flexing things that could break the tether
you could deposit pucks that could communicate,
that would have their own little power supplies
that you could connect. So there are a bunch
of different ways
that we’re looking to try to answer that question, because that kind of
engineering is super fun, the really challenging things.>>Do we know enough
about the cracks on Europa to know if a similar
type of eel like device could get through
the cracks there?>>That’s a good question. There is some
preliminary evidence that Europa may have
a plume as well. It hasn’t been verified yet. We’ve seen some
funky things with the Hubble Space Telescope. We’ve seen some, it
looks like water vapor in places it shouldn’t be, and we, some
scientists went back and looked at the Galileo data. Galileo was a spacecraft that
went to the Jupiter system in the ’90s and early 2000s,
and the magnetometer, that fancy compass,
found some weird readings that might be consistent
with a plume of water vapor. But my understanding of
talking to the geologists and the geophysicists
is that a crack, since Europe is bigger and
its ice shell is thicker, might not propagate all
the way to the ocean, instead if there is a
plume, which Clipper, Europa Clipper would confirm, if there is one
it’s probably from a near surface reservoir. And if that’s true, well
could life get up there, if it could would
it still be alive? Chances are it
might be very salty. Will that affect things? There are a bunch of
things that we would need to think about to understand
the provenance, right? The history of that sample.>>Thank you.>>That’s all the time
that we have for tonight. Real quick, join us next
month, April 16th and 17th, where we kind of what we’re
looking at right here, how NASA observe Earth
from air and orbit. But before we go,
let’s give our speaker another great big
round of applause. [applause] Thank you for joining
us this evening. Have a wonderful evening
wherever it leads you, folks. [jaunty music]

26 thoughts on “The Search for Life: Exploring Ocean Worlds (live public talk)

  1. How about the life of the millions in jeopardy of the planned epidemic of the one and only world we have been given to manage?

  2. Were not from this planet, the gravity is to high, I get chair sores, and Elon Musk says the gravity is barely right so that rockets 🚀 can leave this world 🌎, if you had a choice then maybe chickens can fly

  3. We already know that ET life exists, it’s here on Earth. Unfortunately it’s the most classified subject in the US government.

  4. These mini planets have water and heat sources. There's no way there isn't life. I can't wait to see what it looks like.

  5. FYI: The English subtitles are very, very out of sync. The auto-generated one is working fine, though.

  6. A lot of interesting things was told. Thank you. If there, on Titan, are lake and rivers exist why we didn't have for now an boat or more submarine with sensors, spectrum analysis of all kind ( gas, liquid, minerals, mass). If I understand, at the Titan dark a lot, it's opportunity for using lasers to connect our science boat with orbital device on a high speed. In that case all materials & liquids under the egg shell may be analysed on the surface, as far all material goes through vulcanos and other holes. How to dig down the ice at Titan ? It's the question.

  7. Doesn't matter to me if we are "alone" or not. If the answer is no, we still have no means to interact, displace ourself further than our solar system. Someone need to figure out how to do it.

  8. Quick correction; the letter on exoplanets is the order of discovery, not the order from the star. https://exoplanets.nasa.gov/faq/20/how-do-exoplanets-get-their-names/

  9. If that is Enceladus behind her on the thumb nail, isn't it upside down? My dream is to tour around the orbit of Enceladus. It's the most beautiful thing I have ever seen in space.

  10. Religious and political powerstructures will never let the 'unwashed masses' know about discovery of extraterrestrial life anytime soon. But talk was very good, appreciated! Just imagine an alien civilization 2 million years more advanced than ours :O pretty sobering for us humans who are gravitating to feeling 'special'. Imagine where we would be in 2 million years -> yeah Greta: BUT WE WILL BE DEAD IN 14 YEARS IF YOU DONT PAY MORE TAXES

  11. from 2010 Odyssey Two by Arthur C. Clarke: "ALL THESE WORLDS ARE YOURS, EXCEPT EUROPA. ATTEMPT NO LANDING THERE. USE THEM TOGETHER. USE THEM IN PEACE" mkay bro, why no Europa? Carl Sagan RIP 🙁 i love earth and and our civilization of course but there is no way that we are not alone. Look at the odds, please. Lady holding the speech was AWESOME!

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