Martian Mud: Recent Discovery of Organic Matter on Mars

Martian Mud: Recent Discovery of Organic Matter on Mars


>>Jennifer Harbster:
Good afternoon everyone. I’m Jennifer Harbster. I’m the science section head
for the science, technology, and business division here
at the Library of Congress. I’d like to welcome
you to today’s program that will take us to
Mars, where we will learn about the recent
discovery of organic matter that was preserved in a three-billion-year-old
Martian mudstone. Exclamation mark. Let’s see, so it’s my pleasure
to introduce today’s speaker, Dr. Jennifer Eigenbrode, an interdisciplinary
astrobiologist at Goddard. She specializes in organic
biogeochemistry of Martian and ocean world environments. Dr. Eigenbrode received her
undergraduate degree in geology at James Madison University, her
master’s in geological sciences at Indiana University
in Bloomington, and her PhD in geosciences
from Penn State. As a sample analysis
at Mars Collaborator and participating scientist for the Mars science laboratory
mission, she has focused on the in situ detection
and preservation of organic molecules in
the radiated sediments at the Martian surface. Her work aims to improve
planetary mission design, contamination control, and
instruments measurements that will enable the search
for life beyond Earth. So, please join me in welcoming
Dr. Jennifer Eigenbrode to the Library of Congress. [ Applause ]>>Dr. Jennifer Eigenbrode:
Thank you, Jennifer, for that opening statement, and
thank you all for coming today. This is a great opportunity. I love being able to share
the passion that I have for the stuff that I study. I really do have questions
that I want to answer or I want to see somebody answer
them in my lifetime, and one of them is
trying to understand if there is life beyond earth. And I think that looking on
our solar system is problem one of the easiest places
for us to start. But let me get back
to our topic here. We’re talking about
organic matter. Organic matter that was
recently discovered on Mars. Now, the first thing
you might ask, what really is organic matter,
because let’s clear this up in the very beginning. Organic matter is
carbon molecules that are bound together. They usually have hydrogen,
sometimes oxygen, nitrogen, sulfur, phosphorus, those
things are all put together, and they make these
big molecules. Now, organic matter is
not just one molecule. It’s a whole bunch of
molecules all put together. So, think about yourself. Biology is all organic material. We might have the plastics,
the wood in the chairs, the hydrocarbons that we burn
in our cars and for fuel, all of that, that’s
all organic material. That’s all organic matter. This is the type of stuff
that we would expect to be left behind in a rock
if life had ever existed, but it’s not the only way
of getting organic matter. Okay, so, with that in
mind, we’re searching for organic matter on Mars. That was one of the goals of
the Mars science laboratory, and what I’m showing here is
an image of Curiosity Rover at one of our key locations. Now, where is that? Curiosity is in this yellow
location here on Mars. All of the white dots are
pointing out other places where we’ve had other landings
for our previous missions. But Curiosity is near the
equator, and it’s in a place with call Gale crater. Now, this crater is
about 96 meters wide– I’m sorry, not meters, 96 miles
wide, and the peak in the middle of it, which was formed when
an impactor hit the surface, is about 18,000 feet tall. All right. So, it’s taken us a
long time to figure out exactly what the
story of Gale crater is, but when we first picked out
this location, we had a hunch, it really wasn’t too
much more than a hunch because all we had were a
few images, we had a hunch that there might be evidence
of a former lake there. Well, that was indeed the
case, and I’ll tell you, when we first came across
the outcrops that you see in these first two images, these things are called
fluvial conglomerates, and there are basically lots of
rounded pebbles packed together in a random assortment, and when
you get that type of a feature, it means that you had chunks
of rock, and they were passed through a tumbling type
action to make them round. And that would take some
kind of medium to do that. It had to be water. And this was the
first time like, oh, my gosh, we had a river. We have evidence of a
river, and this is one of the deposits from that. And s we kept chugging
along on Mars, we ended up in a place
called Yellow Knife Bay, and that’s where the mudstones on the right-hand
picture is from, and you see there
are fine layers. These are the sediments that
end up going into the lake, and they trickle down. It takes a while, and they make
this fine layers at the bottom of the lake, and then
when the lake disappears, that turns into rock. That is what we found. So, we had a river,
and we had a lake. We were right. Our hunch took us
on the right path. Okay, these sediments
are everywhere. This is a beautiful picture
looking towards, you know, the dune field on the side,
the mound that’s in the middle, and all of those layers, all of
those layers are from a lake. There’s not, the
lake that we had in Gale crater wasn’t
just there and gone. It came and went. And it may have been
pretty shallow at times, and it could have been
meters deep at other times. But we think that it was pretty
extensive because there’s about 2000 meters of material
for this type of sediment. It takes a long time
to get that. So, the idea is the
entire crater at one point filled with water. All but that middle
peak in the middle, because that peak
is actually taller than the surrounding area. So, when we think
about that time period, Mars was actually more wet, not
the red planet we think of today by something where there
might have been clouds, more moisture around. Exactly what that picture
was like, we don’t know, but at least in order to
have water at the surface for such a small planet, it would take an
atmosphere of some sort. It would take lots of
moisture being pumped into it, and to keep that water there. Now, the interesting
thing about Mars is that it doesn’t look like Earth. It doesn’t have the biosphere, and every reason we could think
of, it’s very similar to Earth, but it took a different path. Well, what was that? Let’s do a comparison to Earth because this is probably
the most fundamental thing that happened in Mars that
took on a different path than what we have on Earth. Earth, shown here,
has a magnetic field, and because we have a core of
liquid fluids, liquid rock, and it’s moving around, it
creates what we call a dynamo. Now, you can’t see
the magnetic field, but what it does is it’s
actually an energy that kind of deflects the solar
wind that’s coming in, and you can see that as the
little yellow lines there. The solar wind is coming in, and
that solar wind is a whole bunch of ionized particles, ionizing
energy, ionizing radiation, and the magnetic field
literally deflects it. So, we don’t experience
much of it. We get UVB. You know, we get a
little bit of UV. We get some visible light
and that kind of stuff. We get that through, but we don’t get the
ionizing radiation, the really intense stuff. All of that stays outside
because of this magnetic field. Now, Mars had one like this too, and we know that because we
see records of it in the rocks, but Mars lost its magnetic
field because the inside of that planet actually
got stiff. It stopped moving around. So, here is a bow shock that’s
created by a magnetic field in yellow, and when that
bow shock went away, an the magnetic field went away, the solar wind blasted
the atmosphere away. And that changed Mars forever. At this point, when
this started happening, ionizing radiation started
hitting the surface. Now, what does that mean? Ionizing radiation is damaging. We are familiar with it because
we’re always told it’s bad for you, right. It does damage to our DNA. So, when we have radiation
come in and it hits things, like a DNA, this is
shown here as a helix, it actually can break bonds. So, this radiation, whether it’s
electromagnetic or a particle, like a proton, it comes in, and
it doesn’t care what it hits. It’s not choosing what it hits. Whatever is in its path,
it hits, and it’s going to deposit energy, which
can break the bond. It can deposit its mass,
which can change the atoms. It can do all sorts of things. That’s if it’s direct. The indirect is, what
if it hit something like a water molecule
in the atmosphere? It may turn into superoxide
type molecules, free radicals, and those free radicals
can do subsequent damage to organic molecules. So, we think of this in our own
lives in terms of what it means for us biologically and
for our medical purposes, but when it comes to a planet, it means that this
ionizing radiation is coming down to the surface,
nonselectively changing it, destroying things,
moving things around. And if your organic
matter is sitting there in a rock near the surface, and all this ionizing
radiation is coming down, it can change it. It can destroy it. So, honestly, when we
first propose this, or when this mission was first
proposed, we knew we needed to look for organic matter, but
we didn’t know if we were going to find it because of this. But we did it anyway. This is SAM. This is the Sample Analysis
at Mars instrument suite. It’s about the size of
a large microwave oven, and it is an incredibly
complex instrument. At the time, it was the most
complex instrument ever sent to another planet, and here
it is, all packaged up, being put into the belly of the
rover that I showed you earlier. You can see they’re all,
everyone’s in cleanroom suits. We call those bunny suits. They’re trying to
keep the contamination down to a bare minimum to make
sure we don’t bring organic matter with us that
we don’t want with us when we get to Mars. Okay, so what happens in
the sand as we heat a sample up that we’ve collected from the
surface and it turn into gases? Those gases then go into what
we call a mass spectrometer, and they ionize. Now, this is deliberate
ionization. We’re trying to break the
molecules up, but we do it in such a control manner that we
can predict how molecules will break, and we use
that information then to tell us what the
molecule compositions are. So, what we get is what we
call mass spectrum, shown here. So, you can see the very bottom
as a mass-to-charge ratio. That’s the unit our
data comes in. And we get a signal for
different types of masses. Those are for each
fragment from molecules. We can take that information
together knowing how the instrument works. We can piece together
what the molecule was. So, in this case, it’s
thiophene, which is carbon and sulfur and hydrogen
together, and you’re going to see thiophene again shortly. Now, the first place we got to
where we found some evidence of organic materials of some
sort was the Yellow Knife Bay. And there’s a picture
of where our scene was. You can see John
Klein and Cumberland. Those are the names of
targets that we drilled, and these are lake
mudstones again. The unit is called
the Sheepbed mudstone. You see Gillespie
Lake and Point Lake. Those are different
types of rocks that are packaged together here. But when we got to
Sheepbed mudstone, that’s where we thought
we had gotten to, these are the sediments from
the base of this crater. This is as low as
we’re going to go. This is where we expect to
find those lake sediments, and indeed that’s what we found. In those rocks, we came across
molecules that are chlorinated. Now, I didn’t mention
chlorine earlier. When I talked about organic
matter, I didn’t say chlorine. I said, carbon, hydrogen,
sulfur, and nitrogen. Sometimes phosphorus. Chlorine is usually
not in there, but here we have chlorine
attached to organic molecules. And there was only about five of them including this
chlorobenzene that’s shown here. This was a fabulous discovery. The first time we’ve actually
discovered organic molecules at the surface, in
situ, at the surface. But we didn’t know what
to do with this data. It was the last thing
that we expected to find. What does this mean? How do we interpret this? What’s the scientific
implications of this? Weren’t sure because this
is not what we expected. This is not organic
matter as we expect to find it in a natural system. So, we kept driving. So, you see here, Yellow
Knife Bay at the bottom, and this is an elevation
map, so we drove up the hill into what we call
the Murray formation, and we came across this
location called Pahrump Hills. And you can see at the top
there, our Rover is way up there by Vera Rubin Ridge. It’s actually past it at this
point, but we drove many miles to get to Pahrump Hills
from Yellow Knife Bay. And you can see on the map
over there, as the crow flies, I think that’s four
or five miles. It took us a while to get there,
but when we got to the base of Pahrump Hills, we got to the
base of the Murray formation, and this is what it looked like. And to a geologist, not
the best outcrop, but hey, we’ll take what we can
get when we’re on Mars. We studied these outcrops
for quite a while, and we chose Confidence
Hills, Mojave, Telegraph Peak, and this location called
Buckskin, [inaudible] site here, as four places where we
wanted to drill and look at the materials that
were in those rocks. And these were all lake
mudstones in this location, and when we got to
Confidence Hills in Mojave, we had a drill hole that looks
like the one that’s shown here. And do you know what’s
fabulous about this? It’s the planet is
red, and that is gray. Okay. So, when it’s
a red, it’s rust. It’s oxidized. Gray is not necessarily
oxidized. Maybe all that radiation
hasn’t destroyed everything that we’re after. That was the first
thought, okay. This is a good sign. We don’t know where
it’s going to go. Well, we got data, and I’m going
to give you sort of an overview of what this data is without
getting into specifics. On the bottom axis is
sample temperature. Remember how I told you
we were heating a sample? And then on the y axis, we
have intensity of that signal and you see a bunch
of squiggles. Now, they’re separated, and
they’re separated by mass, and I put some colors
in there and everything. So, don’t worry about
that interpretation. The point is that when
you get over 400 degrees, we started getting signals
that we could not explain by any other means to say
that it’s coming from Mars, it’s coming from the sample. Okay. So, every signal that
we passed 400, 500 degrees. That’s Martian. We can’t explain that with
our instruments any other way. It’s not something
we brought with us. Now, if you go to the
lower temperatures, there are some complications, and we know that
we can contribute that just from out instrument. But over 500 degree. No, all these gases that
are coming off this stuff is from our sample. And so, you see that I have
marked some of them with circles and squares and upside-down
triangles there? Those are all noting
temperatures where a whole bunch of stuff came out all at once. That is a type of signal
that we get when you combust, or I’m sorry, that’s
the type of signal when you break apart
organic matter with heat. We see this all the time. We have 60, 70 years of data
experience in doing this. We know how to do it. We know what it looks like. So, what I’m showing here is a
bunch of signals that tell us about different types
of molecules, and these are all the
molecules that we detected. This type of stuff. These are all little
fragments of things. So, what you see over here
on the side are these lines. The end, every corner of a little figure
here is a carbon atom, and the line represents the bond
between them, and we just assume that there’s hydrogen all
over that unless we note it. So, there’s blue lines. That’s carbon-carbon. The carbon nitrogen
is in yellow. In the green underneath it, that’s three carbons
linked together. Underneath that, it’s four
carbons linked together. Underneath that now in
pink you got five carbons linked together. In the middle, those
are all rings of carbon. So, six carbons linked
together in a ring with different things
coming off of it. Okay, and then over on the
side, on the far side there, we’ve got molecules that
have sulfur in them. This is exactly what
we would expect of natural organic matter. It doesn’t matter
where you look for it. Meteorites, natural stuff you
find in rocks here on earth, coal, there are so many things. This is what you expect. This is what happens. This is what you get. Hey, we’re feeling
better about this. And, you know, on top of
that there’s another type of experiment that we do. It’s called GCMS. It’s gas chromatography
mass spectrometry. And in that case, what we do
is we actually take the gases that come off after heating it,
and we put it into this column, and the column literally
separates it. So, as the molecules go
through, some of them go through faster than others. One by one, they go
out the other end and into the mass spectrometer. So, we actually separate
every single molecule, and we can look at
them individually. And when we do that,
we get really good data that can clarify what
exactly that molecule is. And on the top, I’m showing in
orange dotted, that’s a blank, that’s one we don’t have
any sample in the system. In blue, this is Mojave sample, and you can see I’ve got
three molecules marked there, they’re the sulfur
molecules, and in purple and flipped upside down, that’s
the same GCMS type system here on Earth in our lab,
operating the exact same way as the one on Mars. And notice that the peaks line
up to the ones, on the bottom, the first three peaks line
up to the ones on the top that have the molecules marked. That is perfect confirmation that we know what
we’re dealing with. And we have mass spectra that help tell us
exactly what those are. So, we have two types
of analyses that show that these molecules are there. Now, what’s important is
about the carbon sulfur. Carbon sulfur molecules
are predominant on Earth in the rock record, and it’s
taking years of research for organic geochemists
to figure out that that sulfur is the mechanism by
which a lot of organic matter that we use in petroleum,
in coal, is preserved, for millions to billions
of years. Sulfur is key to all of that. It doesn’t always stay in
that organic matter on Earth, but it may be the first thing
that happens that keeps it from being destroyed and getting into the rocks in
the first place. So, we have sulfur. That’s a key thing that probably
helped preserve this organic matter on Mars. Just like it does on Earth. But the other thing that
probably happened is that this organic matter,
clearly it’s refractory. It’s hard to chemically
break it up. Otherwise, the radiation would
have broken it up or oxidants in the rocks would
have broken it up, something might have happened. So, how is it that it prevailed? Well, we see two molecules here. I’ve got benzene
and propane shown. Two separate molecules. These are the types
of things we observed, but because of the temperature
at which we observe them, they’re telling us, the data
is telling us that it’s coming from something much larger. Giant molecules,
macro molecules. We call these kerogen,
giant stuff. When I say we discovered organic
matter on Mars, this is the type of stuff that we discovered. Not directly, but we use
the best methods we can to determine what’s there. So, where did this
organic matter come from? Was it Martian life? We really don’t know,
and to kind of, you know, shed a little light on this,
we took a Jurassic paleosol, this is an ancient soil
from 150 million years ago. You could see there’s an image
of what that would have looked like back then with dinosaurs and the giant trees,
the sequoias. And here is the rock
in the middle, and there’s this thing
called the great dirt bed. We looked at that. It’s just, you know,
it’s a good candidate. We looked at that. It’s old. It has
organic materials in it. It has coal in it,
and would you believe that we saw the same
type of signals. Gas is good. Cool, right. Same type of signals, nothing that is diagnostically
different. But what else is there? We looked at meteorites. So, here’s an example of the Murchison
carbonaceous chondrite. This is the stuff that’s
floating around our solar system from when it formed, and it’s
raining down on all the planets. And it has been raining
down on all the planets since the planets formed
in the first place. Okay, so this is
solar system material. It’s not related to life in
any way and how it formed. And we analyze that using the
same type of methods, like SAM, and we got the same type of
results of what we saw on Mars. And then we got a
Martian meteorite, and we put that into it,
the SAM type of analysis. This one is from a
geological source, so rock processes formed it. No life involved. Rock processes. People had synthesized
this stuff in the lab, we know its rock processes. And it created the same signal. Okay. So, you see,
there’s a pattern here. The data that we have is not
diagnostic of the source. It just tells us that
there’s organic matter there. We do not have enough
information. That’s where it leaves us. So, our conclusion is
the organic matter has been preserved. This is fabulous. We [inaudible] there. It’s been there for three
and a half million years in lake sediments, and
it was preserved probably through macro molecules,
some sulfur, and the mudstone certain helped. But the source of it is unclear. But realize that
Viking went looking for organic matter 42 years
ago, and it didn’t find any. Well, we finally found some. Why is this important? Well, if Gale crate
contained life three and a half billion years
ago, we all know that it did. But if it did, then
perhaps there’s fossils of that life still around. Maybe it’s preserved. Because the organic
matter is preserved, the fossils of that life
could be preserved in it. We just need to come
up with the right tools or I should say suite of tools and uncover those
fossils and observe them. We’ve taken the first
step in the search for ancient life on Mars. The other thing is this
lake was habitable. We know that from
other geochemistry. But it not only supported
autotrophic life. This is the type of
life that uses CO2 as its carbon source,
carbon dioxide. It also supported heterotrophic
life, the organisms that eat other organic
matter, like us. We eat organics. Okay. So, all the types of metabolisms could have
been supported in this lake. So, it’s been more than 40 years
since we started the search for life and the search
for organic matter on Mars. Now that we have evidence of
the ancient organic matters that are preserved,
we are one step closer to determining its source. So, what happens next? Well, we’ve got two
rovers that are going to be heading soon to Mars. One is the ESA’s 2020 ExoMars
rover, and the key thing about this one is it’s
going to drill deep. Now we talk about
that radiation, that radiation really
does a lot of damage at the very top surface, and
the further down you get, the further away you
get from that radiation. Mars is an ancient surface. We’re talking millions of years
old, tens of millions easy, hundred millions possibly. So, the surfaces you
see in these pictures, imagine that’s been
like that for millions and millions of years. It’s a lot of radiation,
a lot of time. Drilling deep gives
us an opportunity to get away from all that. I can’t wait. I honestly cannot wait, and we
have another instrument on there that can provide not only
the same, similar type of information that
we got from SAM, but even more expensive
information that could tell us if there are fossils there. The other one is the Mars
2020 rover that NASA is going to be sending, and
it’s a caching rover. It’s going to go
around, and it’s going to collect little samples
and leave them on the ground, and later, we can go
back and pick those up and bring them home. Okay. That’s the plan. It’s going to take a lot,
many years for that to happen. There could be other
missions going to the surface. Perhaps ones that
target very specifically if there is life
there in another way. So, we talked about how
modern-day Mars here was more like this ancient Mars. That’s of the rock
record we looked at, but everything I just talked
about was for the ancient stuff. Let’s go back. Let’s talk about modern
Mars for a moment, okay. We just found organic
matter in an ancient record. There could have been
life on Mars three and a half billion years
ago that produced it or was using that
organic matter. We don’t know that it was there,
but it could have been the case. Back then, Mars was much more
likely to have supported life. If that life ever existed,
what happened to it? It probably went
into the subsurface where taking refuge away from
all that ionizing radiation and all the oxidants
on the surface. But here’s what,
here’s the kicker, here’s what we know
about life on Earth. It lives in all sorts of
crazy extreme environments. Here’s Dallol, Ethiopia. It has a pH of less than one. And look at all that
green slime in there. Those are cyanobacteria
living happily in this crazy pH environment. Okay. Survival for a half
million years in permafrost, organisms surviving that long
in a super cold environment. Here’s Blood Falls
in Antarctica. It’s draining an iron-rich lake that is below the glacier,
away from sunlight. And that is loaded
with organisms. And then there’s even the
Atacama Desert, probably one of the driest places
we’ve extensively studied, and it has microbes that
they’re barely doing anything. They’re around, and
they hang out. And then when the conditions
are right, they, hey, okay, we’re doing something. Let reproduce. Let’s make more cells
and everything, and then things got dry again. Let’s wait and wait
and wait and wait. And didn’t they do
something later? Okay. This is what
extremophiles are like. We know this from
examples on Earth. We have this rampant
biosphere here. Mars certainly doesn’t. But Mars could have an
extremophilic biosphere. Here’s another example. I love this one. Chernobyl, it has,
they found this fungi, Cryptococcus neoformans. It lives off of gamma radiation. You take the gamma radiation,
right, it stops doing stuff. It thrives on it. It needs it. This is an organism that
adapts to the radiation. Hey, maybe organisms adapted to
some level of radiation on Mars, something that we’re
not used to. There’s microbes
living on the outside of the International
Space Station. Okay, so, organisms adapt, especially if they
have a lot of time. So, Mars changed. It had a lake at one point. It probably had environments
closer to what we’re familiar with,
but today, it’s different. So, perhaps there’s an
extremophilic subsurface biosphere on Mars. It’s not the same as
what we have here, but it could still
have a biosphere. And there are places that we
might choose to go look for it. Some of the examples
that people talk about are these recurring
slope lineae. This is a slope here of a
crater, and there are seeps of water coming out,
ground water seeping out. So, subsurface materials are
coming out to the surface, and then they’re draining down,
and they take repeated pictures, and they can see those wet
spots changing by season. Or, on the other side here,
we’ve got the exposed ice in the northern plains. This was exposed by
the Phoenix lander. Ice today could have been
wet ground in the past, because one of the crazy
things about Mars is that unlike Earth
it has an orbital, a tilt to the plant
that’s pretty shallow. Mars tilts a lot. So, you can imagine when
that axis moves back and forth the seasons
change dramatically. That wet spot, that
icy spot there in the northern plains could
have been a wet spot many millions of years ago or
even hundreds of thousands of years ago, which would
have been nice for life, especially extremophilic
life, if it can tolerate that. And then this is the big one. We don’t know if
there’s a Mars ecology. We don’t know if it’s in
the subsurface or not. In the past, or even now,
we don’t have those answers. We do not know. But what happens in the future? It doesn’t matter
if it’s past or now. It almost doesn’t matter. What happens in the future? Were going to send humans. Humans have a biome around them. We’re going to be
sending that to Mars, and we will do our
absolutely best to contain it, but there will be inadvertent
releases to the environment. Okay. So, whether
we intend it or not, there will be some
sort of life on Mars. Maybe it going to die out because it doesn’t
like the radiation. You know, maybe it’s
not going to survive, or maybe it’ll find a way
to adapt in its own niche. It’s hard to imagine what that
would be, but it’s possible. We want to study that. And if there is a Martian
subsurface life, what happens when the two interact? Are we going to be
able to observe that? Do we have a chance to
study that if it happens? It would be a lot easier to
study something like that if we first knew
if Mars had life. So, honestly, you know,
it would be wonderful to do a really good targeted
study looking for life on Mars now, modern-day
life, in some place where we think it would most
likely be if it’s there at all, before we send a human. Whether or not that’s
in the cards is yet to be seen, so we’ll see. And with that, I’m going
to bring us to a close and answer any of
your questions. [ Applause ]>>Jennifer Harbster: In the
question and answer period, when you answer the question if you can repeat
the question again.>>Dr. Jennifer Eigenbrode:
Okay.>>Jennifer Harbster:
Okay, do we have questions? You’re speechless?>>Dr. Jennifer Eigenbrode:
Oh, ask anything, really. [laughter]>>Can you tell me– [ Inaudible Comment ]>>Dr. Jennifer Eigenbrode: Levels of radiation
on the surface, yes. We do know what those are because on the Curiosity rover
there is an instrument called rad, and it actually
did these measurements. And there’s different ways
of reporting that value, but if you take all of the types
of radiations that are measured, it was 76 millirads per day. Oh, geez. I might be
getting my units mixed up. It was a number that we
were not too surprised by. It’s not very high, no. [ Inaudible Comment ] That’s right, yeah. It’s not very high, but
in this case when you talk about exposure to that over
geological time scales, it makes a big difference, yeah. Uh-huh?>>The atmosphere then, do we
know what it maybe was way back when [inaudible] could have been versus what it is
today [inaudible], what you have now
versus what was it.>>Dr. Jennifer Eigenbrode: That’s heavily debated
on what that was. First off, you had to have
a warmer planet in order to have all the liquid
water around, and in order to have a sustained
body of water, you have to have a certain
amount of atmosphere. In order to sustain an
atmosphere, particularly when the magnetic
field is already gone, it means that you have
to be pumping more stuff into the atmosphere than
is being stripped away by the solar wind. So, those types of details
are starting to be modeled, but we just don’t have
enough information on it yet. I think that the Maven mission, which studied the upper
atmosphere, really gave us a lot of insights into the
possibilities of what happened as far as the loss
of the atmosphere and how different
ions actually interact with that atmosphere
to make it go away. That’s the type of stuff that
makes the models possible. So, now we’re waiting for the
models to give us a better idea of what it might have been like.>>So, do you think
humans on the surface of Mars can do the search
for life just as well or better than rovers, robots?>>Dr. Jennifer Eigenbrode: No. I think that they could
do it in a combination with rovers but not
on their own. Because an astronaut, even
in suit that is super clean or as clean as they can
get it is still going to have some inadvertent
level of biology on it. So, when you’re talking
about looking for extraterrestrial life,
if you find something, you have to be able to
demonstrate, it’s not from us. It’s not, because otherwise we
will always be skeptical of it. We will always question it. So, when we take an astronaut
to do a study like this, the advantage is to have a
rover go collect the samples and get them contained. The rover we can keep clean. Let the rover go out
and get the samples. The rover collects them,
brings them into a facility, a habitat of some sort that
has a science facility, and then you engage the
astronaut in the analysis of that sample to
look for signs of life and understand it if it’s there. And the advantage there is
that you don’t have to wait for an analysis to be completed and then send all the data
back home, have humans look at it there, and then send
commands back to respond to what the data
was telling you. The astronaut right there
on the spot sees it, responds, does next test. Sees it, responds,
does next test. The amount of data and
observations and the direction of all that is strategically such that it increases the
science return by so many order of magnitude, and that would
be really, really critical for not just making us feel
more confident about what it is that we’re looking at, but if it
does look like it might be life, learning something about it. It’s really going to be
a combination of the two, and honestly, in every single
scenario I’ve ever heard people talk about, that’s
really what’s involved. It’s the two.>>But the research [inaudible].>>Dr. Jennifer Eigenbrode:
Oh yeah. Absolutely. I am convinced that if you
figure out what you want to study, what type of data
you need, and the requirements for getting that, that engineers
will eventually figure out how to make that possible
with a lander or a rover, some kind of robotic system. So, it’s doable, we can do it. We absolutely can,
and we’re ready to. Missions are being
proposed to do it. But there are huge advantages
to involving astronauts at some point later in the
whole strategic process. Did I answer your question?>>Yeah. It just
rounds that out. I mean they wouldn’t necessarily
have to be at the surface. I mean they could be
orbiting [inaudible].>>Dr. Jennifer Eigenbrode:
Oh, yeah. If you get the samples
to them, sure. Or, if they are able to
engage on a very quick time with a rover at the surface
because they’re in orbit, yeah. Yeah, we call that
low latency science. It’s a low, it doesn’t
take much time. It’s low latency between an
observation versus a response from that observation and
determining what to do next. Yeah. Right now it’s
a long time. You got to send the
data back to Earth, have a team of scientists
look at it. It takes a couple days, then
you respond, yeah [inaudible]. There’s a question
in the back there. Yeah. [ Inaudible Comment ] I’ve heard two cases,
two scenarios, and I honestly do not know
if they’ve been updated. The first one is that Mars
is a sixth the size of Earth, and part of the reason why
Earth still has molten core, a liquid rock-type interior is
because of all of the radiation, all of the natural radioactivity
of the rocks produce heat, and that keeps it melted, okay. So, if it’s one-sixth the
size, it has that much less of the radioactivity happening and the heat that’s
generated from that. So, it doesn’t have a
natural heat source of its own in the interior that’s
going to sustain it. The other thought is that
perhaps the Hellas Basin, which is a gigantic crater in
the southern hemisphere of Mars, it’s huge, and it breaks up the
magnetic field lines that we see in the rocks, which tell us that
there are these rocks that had, that were deposited and made
when there was a magnetic field and then the impactor
that came in and hit that area disrupted all of that
and created this gigantic basin. Well, people have modeled what
that impactor would be like, and it could have
been big enough to disrupt the interior
of the Martian core. Perhaps that had
something to do with it. Maybe it was a combination
of the two, but honestly, that’s as about as far as
that has gone [inaudible].>>But Earth has not
experienced a similar impact.>>Dr. Jennifer Eigenbrode: No, the only similar impactor would
have been maybe the generation of the moon, and at that
time that was so early in the formation of the Earth that it didn’t have
same type of response. Yeah. So, no, Earth has
not gone through that. [ Inaudible Comment ] Yes and no. If a large impactor hit, having
something that was loaded with organic material and having
it that size of what was needed to excavate Gale
crater, that’s something that we’re not familiar with. It’s not, say it’s not possible,
but we’re not familiar with it. A lot of times the type of
impactors we get are other types of rocks that don’t have
a lot of organic material. But, hey, right now
everything’s a possibility. And if that were to happen,
that impactor would have broken up into little pieces,
and it would have, and it excavated the hole there
too, so you have a mixture of whatever it excavated
out of the hole and all of the impactor material, it
all kind of blends together and gets scattered about. Then you have water coming in. Now, we do have evidence of some
water flowing on the surface and coming into the crater,
but we do think that most of that water actually
came from below, because there’s probably
ground water and ice down below when this happened, and when
you had this impactor come in, it generated so much heat,
we had hydrothermal activity. All that stuff melted, and
all that water kind of seeped through the bottom and come up. So, all of the stuff,
all the rocks scattered about including the impactor
could have washed in, blown in, and then been part of
the lake’s sediments. That is possible. But it’s, we just don’t know. I think that’s where
we’re going with it. We just don’t know. There are so many questions. People try and model
this type of stuff, and having organic matter coming in from large impactors
is not the predominant way of getting solar system
related organic materials to the surface. What’s more likely
to have happened if it wasn’t organic matter
initially from Mars is that we have these things
called micrometeorites, and it’s like dust particles. They’re super tiny. They’re incredibly hard
to collect and study. But anyway, these
things are raining down, and they’re so small
that they survive getting through the atmosphere. These things have been raining down on all the planets
since they formed. Well those things
have organic matter in them, actually quite a bit. And so, while a few in a rock
don’t make much of a difference, because it’s such a small
amount of organic material, if you talk about having a lake,
and you’re collecting stuff over many, many tens
of hundreds of millions of years’ time, it
can accumulate. It adds up. And it’s not just what falls
in, it’s what’s blown in, or it’s what’s washed in. So, it’s possible that
the organic material that we’re looking at,
that we found with sand, is actually the stuff, I looked
at the carbonaceous meteorite. It’s the same type of stuff. It could be that. It could be these dust
particles that came in from the solar system, yeah. So, hey, but you know what? Whatever we think has happened
will change in, you know, the next ten years as we
learn more about Mars. It’s part of the fun
of this research field. Yes?>>Are there any plans to
drill elsewhere on Mars where it’s not a
creator, no impact?>>Dr. Jennifer Eigenbrode:
Okay, so the question is, are there any other plans
to drill elsewhere on Mars, and the two rovers that
I mentioned at the end, both of them have
drilling capabilities. And the Mars Curiosity rover
that was the point of this site, it had a drill on it, or I
should say it still does. But the difference is,
the Curiosity rover and the Mars 2020 rover only
drill down 5 centimeters. It’s a really shallow
drill hole. But the ExoMars rover is
supposed to go down two meters. That’s, I mean that’s huge. That’s going to give us
access to samples that were, as long as we get the samples
out of the ground and analyzed, we are going to learn something
important, and we’ll have to wait and see what that is. Now, there are other proposals
out there to drill deeper into the ground in
other locations. One is to drill into
the northern plains. I know I showed you that picture of the ice the Phoenix
had excavated with the little scooper, and it had shown there
was ice not to far down. Well, there’s a mission that’s
proposed to actually go and look at that ice by drilling
deeper into it. So, and if that were the case,
it would look for signs of life. It’s designed to do that. But that is not funded
yet, and it’s still TBD. We don’t know what’s
going to happen. So, we’ll wait and see. There may be others. People are talking about
drilling, for multiple reasons. Not just for science sake,
but also for the sake of excavating water
that could be used by our astronauts
in the future, yeah. Okay?>>You said that there were
some questions that you wanted to have answered
or maybe a couple of them off the top [inaudible].>>Dr. Jennifer Eigenbrode:
Yeah. I think some of the
biggest questions for me are does Mars
host life now? It’s such a critical
turning point in our thought of that planet if we come
anywhere close to answering it. If we go look in the places
where we think it’s most likely to be, and we don’t find it,
maybe we’d look a second time. If we don’t find it, wow,
it’s either something so drastically different
than anything we expected and we looked in the wrong
places or just not there. And that gives us, sort of takes
off a question and allows us to move forward in new science
directions, but until we get that answered or at least
make an attempt to answer it, it’s like we have a hurdle in
front of us, we have this block. If there is life
there, the exploration of Mars will change forever,
completely different path. So, it almost to me, it almost
doesn’t matter which one it is. I just want to, I just
want to see it happen. I just want to see it
happen, I just want to be able to put some, shed some
light on that question. That’s the big one. The second one would
be, what happened to it. Why is it not a biosphere
on Mars. I’ve watch the discovery of
extremophiles over the decades as a student and then a
researcher, and the boundaries of life just keep going
further and further away, and it’s just astounding
to think that organisms have
found a way of adapting to so many different niches. So many crazy places that even
physically we didn’t think it was possible, but somehow
they found a way of doing it. And they’re there. Okay, great. So, if Mars had a more
rampant biosphere at some point because it had lakes and it
had, it was easier for life to survive if it was there. Why did it not adapt
to what’s there now? Why did it not adapt
to all that radiation? I would almost think that
drill a little further down and you might see something, like we do if we
go to the arctic. You go, you crack open a rock,
and a you look a few centimeters into the rock, and
you’ll actually see layers of colored organisms
in the rock. They figured out, get away
from the worst stuff, but hey, this is a happy time
right in here. So, you know, they
managed to do something. I would think that
Mars would have that. Those are the big ones. Then the other questions really
are more about well where else in the solar system
might they be, and we’d have those
ocean worlds. And honestly, if we
find evidence of life on an ocean world, it might
be that it’s a second genesis of life completely
independent of Earth’s. And if we find that or we find
evidence of life on Mars, if, these are all ifs, then when we
look out in the solar system, and we look out at the stars at
night or through our telescopes, like Hubble and our future one
of James Webb, and we see all of these galaxies out
there, and we wonder about all those exoplanets, we
think about there might be life out there, we’ll actually have
some footing, some basis to say, oh yeah, there could
be life out there or, why would there be
life out there if there’s no life here
elsewhere in our solar system? A likely place for it to be. It kind of stabilizes or it moves us a little bit
further away from what we think, what we want to think, what
we assume to having some basis for understanding
what’s possible elsewhere in the galaxies,
in the universe. I’m not going to see the answers
to all this in my lifetime, but the next generations might. [ Inaudible Comments ] Yes, so the question
is, what’s the role of the inorganic materials
in the preservation of the organic materials, and
that’s a fabulous question. Earth is a system on its
own, and every little package of Earth, whether it’s
a little rock or a leaf or ourselves, we
are systems too. And all of the stuff that
in that system is related to each other and its
composition and how it works. So, if we think about that
on Mars, Mars as a plant, as a system, every bit about
it influences the other bits. And if we zoom in on a
rock or even the crater, like Gale crater, or the
rocks that we were looking at and that organic material, that organic material
is part of a system. And it exists because of
the rest of that system, the rest of the composition, which is the inorganic
materials. They most certainly have a huge
impact on the preservation, and in fact, one of the things that I think the Mars
2020 rover is going to tell us is more
about what that is. Because it has the
right instruments to actually examine
the interface between the inorganic
and the organic. So, the minerals, how the
organic matter is packaged within them. Does it tell us something about
how the organic matter formed or how it got sandwiched between
minerals and then preserved? All of that is something
that we need to learn a little
bit more about, and the Mars 2020 rover is
probably our first next step in making progress
in that direction. The other way that we can learn
about it is through meteorites. Luckily, there have
been Martian meteorites, so pieces of Mars
have landed on Earth, and we’ve been studying them. There’s, they’ve been
around for decades. People have actually been able
to figure out that they’re from Mars based on
their isotopes. And we’ve learned a lot, and because our instrument
techniques on Earth keep advancing,
we go back to those over and over again, and we learn
more and more about them. But most of those, if not
all of them, are from deeper in the planet rather than
rocks like Gale crater. So, they’re not telling
us about lake sediments. They’re telling us about
volcanic rocks deeper down, and that’s important but
it leaves a lot of pockets yet to be filled
in our knowledge. Oh, there’s one more
question back here. [ Inaudible Comment ] Many, many countries are
involved in Martian exploration. The Mars science laboratory
involves several countries. We have teams of scientists
from Canada, France, Spain. Let’s see, Germany, there’s
quite a few European countries. We have lots of engagement
in that front, and then the European space
agencies got there ExoMars rover, that is an
international effort, and then there’s the
Israelis are interested. The United Arab Emirates
now have a space agency, and they’re interested in
supporting Mars research. The Chinese are interested, and I’m not exactly sure
how much India is involved in any one of those, but they
have expressed interest as well. So, their most certainly is
international involvement, and how that manifests itself is
something I’m not an expert at, but I can tell you that
when the scientist get in the room, it’s engaging. And we’re all after
the same type, answering the same
type of questions.>>Thank you. [applause]

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