Our neighbor, Mars,
fascinates us.
It's a planet
that is similar to Earth,
but with some big differences.
Mars is rusty, dusty,
frigid, and frozen.
It ain't the kind of place
you want to raise your kids.
Past missions suggest that Mars
was once a very different world.
The Mars we see today has
completely changed
from the Mars of
a few billion years ago.
If I had
a time machine to visit Mars
in the past,
I would go in an instant.
Without a time machine
to explore
ancient Mars,
we employ a team of high-tech
robot investigators.
We've got an entire fleet
of robotic spacecraft
exploring the planet.
Working together, they dig
into Mars's past to answer
the ultimate question...
Did Mars once have life?
February 2021.
The newest robot investigator
speeds towards Mars,
the most advanced rover
NASA has ever sent to
another world.
This is Perseverance.
The goal of
the Perseverance mission is
to look for signs of
past life on Mars.
First, it must navigate safely
to the surface of the planet.
Every landing
has its own dangers.
Because the rover must
be autonomous,
it has to do everything
without our help.
Perseverance enters
Mars's thin atmosphere at
close to 12,500 miles an hour...
and deploys a parachute.
The parachute slows Perseverance
to 200 miles per hour.
Still too fast to land safely.
To prevent a violent impact,
the rover must activate
the sky crane.
When I first saw
the sky crane concept,
I thought, hm, the engineers
are kind of losing it.
It seemed to me like
a really crazy idea.
Perseverance
activates its jetpack.
Retro rockets slow
the lander's descent to a crawl.
Then, 66 feet above the surface,
the sky crane uses cables to
gently lower the rover
to the ground.
Step one in
the search for Martian life,
find evidence of liquid water.
A good place to start is
the 28-mile-wide
Jezero Crater.
Perseverance has landed in
a crater called Jezero, and this
looks like a place where there
was liquid water in its past.
And the reason we think this
is because
there's this beautiful delta
deposit right in the middle.
Perseverance turns
its high-resolution cameras
onto a cliff side in the crater
and discovers giant five-foot
boulders near the top.
A clue to how they got there may
come from the first probes
to visit Mars.
One of the very first things
we noticed about Mars
when we first sent probes there
with Mariner and Viking was
that there were these huge
channels on the surface of Mars.
Looking at
these enormous landforms,
we realized that,
in some places on Mars,
there may have been
enormous floods,
bigger than almost anything
we'd ever seen on Earth.
Flash floods on Earth
cause similar rock formations to
those found in Jezero Crater,
suggesting that powerful,
fast-moving torrents carried
the giant rocks found by
Perseverance and dumped them
at the top of the cliff.
Perseverance is just one
member of an elite team
of robots patrolling the ground
and spying from the air.
The Mars Atmospheric
and Volatile Evolution
Orbiter, or MAVEN,
investigates Mars's atmosphere.
MAVEN smells really good.
It smells
the Martian atmosphere.
It tells us what
the Martian atmosphere
is made of all across
the planet.
Then there's the MARS
Reconnaissance Orbiter.
As its name suggests,
an orbiting spacecraft
that images surface of MARS.
The M.R.O.'s
high-resolution cameras
can identify surface features as
small as a kitchen table.
And joining the orbital crew,
The European Space Agency's
MARS Express.
With its
ground-penetrating radar,
it searches for evidence of
subsurface water.
And, on the Martian surface,
a group of high-tech landers
take a closer look,
including the team's quake
specialist, Insight.
This lander probes
deep beneath the surface
to discover how Mars's interior
shapes the planet over time.
The Insight lander on MARS has
a really simple concept.
You land a spacecraft
on the surface anywhere
on Mars and then just listen
for Mars quakes.
And 300 miles south of
Insight, veteran rover,
Curiosity is exploring
the Gale Crater.
The mission goal for Curiosity
is to look for habitability,
and so that's environments
in which life as we currently
understand it could exist.
Curiosity searches
for evidence of calmer,
more permanent water in
Mars's past.
Investigating layers of rock
at the base of Mount Sharp,
a three-mile-high mountain in
the middle of the crater.
The rock layers
start way up at the top of
Mount Sharp, and they move
progressively downward,
and basically, we're going
backwards in time until we get
to the very bottom, and the very
bottom is actually really old.
Mount Sharp was built
over millions of years,
layer by layer.
The rocks at the base of
the mountain date to
These rocks are made up
of very fine layers
and could only have been
formed in calm water.
These sedimentary layers were
formed when Gale Crater was
a lake, and sediment settles
out, and you get these
beautiful layers.
Curiosity explores
more of Gale Crater
and discovers rounded pebbles,
like those we find on Earth.
When you see a rounded
pebble on Earth,
you know that that got rounded
in a river channel.
Some of them used to be angular,
but their angles all got
knocked off by being rolled
and rounded and moved by water.
So we're very excited when
we see rounded pebbles on Mars.
The rock layers
and rounded pebbles
tell us that over
three billion years ago,
Gale Crater
was a lake fed by rivers.
It was so exciting
to understand liquid
water in the context of
Gale Crater,
where Curiosity is, and that's
just because what we see there
is this long-lasting,
freshwater lake, and that's
not like anything else
we've seen on Mars before.
Imagine standing on the edge
and looking out
at this big, beautiful
blue lake
shining in the distance.
What if there were just
a whole array
of craters filled with water
off in the distance?
It would be so beautiful.
And a good place
for life to evolve.
Mars was a nice place.
It was probably more like
Earth is now.
So it wouldn't surprise me
if it's supported life.
We're talking microbial life.
We're not talking, you know,
Marvin the Martian or anything
like that,
but life still is life.
Any water Mars once had
is now long gone.
To stay liquid,
water needs warmth
and atmospheric pressure.
So, hundreds of miles
above the planet,
orbiting members of the team
investigate the mystery of
Mars's missing atmosphere.
While robot team members,
Curiosity and Perseverance,
work the Martian surface,
eight probes orbit the planet,
searching for clues about
Mars's ancient wet history.
Leading the pack is MAVEN.
Its mission...
To solve the mystery of
Mars's lost atmosphere.
Today, the atmosphere of Mars
is incredibly thin.
It's only about 1 percent
the atmospheric pressure
here on Earth.
The weight of gas in
an atmosphere pressing down
creates pressure,
and that pressure dictates at
what temperature liquids boil.
Here on Earth at sea level,
the boiling point of water
is about 212 degrees Fahrenheit,
but up here in the mountains
near Denver,
we're at a higher altitude.
We've got a lot less
atmosphere pressing down on us,
and so it boils
at a lower temperature.
Let's put a thermometer in here.
There's 200 even right there.
That's a lot cooler boiling
temperature than at sea level.
Now, if you go to even higher
altitudes at 100,000 feet
here on the Earth,
the air pressure is about
what it is
on the surface of Mars.
On the surface of Mars,
water will boil effectively
at ambient temperature.
We wouldn't have
to heat it at all.
You just put a glass of water on
the surface of Mars, and it'll
boil and disappear away.
But the planet's surface
tells us that dry Mars
was very different in the past.
When you see things
like river channels
that probably took millions
of years to carve,
that gives you an idea that
the atmosphere was once very,
very different.
It had to be thick to allow
liquid water to exist on
the surface.
To investigate
what happened to that thick
Martian atmosphere,
MAVEN swings into action.
One of the main objectives of
the MAVEN mission was to
measure argon on Mars.
There are slightly different
kinds of argon.
We call these isotopes,
and basically,
it means that there's just
an extra neutron in the nucleus.
So there's one type of argon
that's just a little bit
heavier than the other type
just by one neutron,
not by much.
High up in the atmosphere,
MAVEN tag teams with Curiosity
down on the surface.
They measure the amount of
light and heavy argon.
Now, what's special about argon?
Well, argon
is not very reactive,
doesn't really get involved in
a lot of chemistry.
It's not really absorbed by
rocks, doesn't change much.
Once it's emitted,
it kind of hangs around.
And that makes it very
valuable, because it means it
stays in pretty much
its pristine, pure form
through the history
of the planet.
When the researchers
back on Earth
compare the readings from
the two Martian robots,
something doesn't add up.
With Curiosity
on the surface, we see
a certain ratio of heavy
to light argon.
And we expect that same ratio to
exist up in the atmosphere,
but with MAVEN,
we see a different ratio.
We see far less
of the light argon
than we do down on the surface.
So something is
messing with that ratio.
The only thing we can think of
that can mess with
the ratio of argon is
the solar wind from the sun.
The sun spits out a constant
stream of particles
called the solar wind.
The wind is over a million
degrees Fahrenheit
and travels at up to
When it reaches Mars,
it strips away
gases high up in the atmosphere.
The lighter the argon is,
the higher it gets up into
the atmosphere.
That means that that gets blown
away preferentially
by the solar wind.
The heavier argon stays
a little bit
lower down and a little bit
more protected.
So when you look at the ratio
in the atmosphere of the light
argon to the heavy argon,
it gives you an idea of how
much has been lost over time.
MAVEN's data reveals that Mars
has lost 65 percent of the argon
from its atmosphere,
and the solar wind continues to
bombard the planet.
The atmosphere of Mars is
being stripped away by
solar radiation by a quarter
of a pound every second.
This rate of atmospheric
loss leads to one conclusion.
The solar wind
robbed Mars of its once
thick atmosphere, and with it,
the planet's water.
But a question remains.
We know that Mars's
atmosphere was much thicker
in the past,
really similar to Earth's.
So why is it
that Earth's atmosphere
is still mostly there,
whereas Mars's has been
stripped away?
Earth has a protector,
a magnetic field
that shields our atmosphere
from the ravages
of the solar wind.
The Earth's
magnetic field is generated
deep in the core.
There are actually two cores.
There's a solid inner core
and a liquid outer core,
and that solid inner core
is delivering
heat to the outer core,
and as it does this,
it causes convection currents.
The convection currents
pull electric charges around
and cause magnetic fields
to fold in on themselves.
We call this a dynamo,
and this is what's capable
of generating powerful
magnetic fields.
The magnetic field forms
a protective bubble around Earth
that deflects the solar wind
away from our planet.
Did Mars once have
its own force field?
To find out,
MAVEN hones in on some
ancient volcanic rocks
on the Martian surface.
It detects faint
magnetic traces.
Martian rocks,
typically in the form of lava,
become magnetic
when the iron particles
in the rocks become aligned
with the magnetic field
that's active at the time,
and then as the rock cools,
those things
get frozen in place.
That sort of freezes
a magnetic field into place.
What that tells us,
that these volcanic materials
were erupted at a time
where there was a magnetic
field present on Mars.
Dating the magnetized
rocks reveals that Mars had
an active magnetic field for
almost a billion years.
This means
that the atmosphere of
Mars was protected
for those billion years,
and if the atmosphere
was protected,
the liquid water was protected.
And if that liquid water was
a home for life,
then that life was protected.
But something happened to
bring Mars's force field down.
To discover what, our quake
specialist, Insight, is ready to
burst open the mystery of
the planet's lost
protective shield.
Robots are rewriting
the history of Mars.
They found that Mars once had
a magnetic field that
protected its atmosphere.
Now, another team member,
Insight,
probes the planet's interior.
Its mission...
To discover if the secret of
the planet's lost magnetic
field lies
beneath the Martian surface.
Insight was developed with
the world's best seismometer.
This is a really precise,
really delicate,
really sensitive instrument,
and it just was placed on
the surface
and started listening.
Insight listens for seismic
vibrations, called Mars quakes,
as they travel through
the planet's interior.
It's detected
quite a few Mars quakes,
but these were very small,
but then it detected
two much larger ones.
And these were interesting.
Not only were they more
powerful, but they were coming
from the direction of
Cerberus Fossae,
which is a very interesting
region on Mars.
The magnitude 3.1
and 3.3 quakes
came from Cerberus Fossae,
a series of trenches that
stretched for 750 miles across
the Martian surface.
Some fissures cut through
impact craters that
are only a few million
years old.
This means Cerberus Fossae
must be younger.
Insight teams up with
the Mars Reconnaissance Orbiter,
flying hundreds of miles above.
This eye in the sky
spots an ancient lava flow,
spreading out
over a three mile area.
Dating of the flow
reveals that it's recent.
The Mars Reconnaissance Orbiter
spotted,
in the Cerberus Fossae region,
some lavas that appear to be
about 50,000 years old.
This is crazy young for Mars.
Mars has been around
for billions of years.
Humans were around on Earth
that long ago.
So this is really recent.
Based on the fact that we had
these two Mars quakes recently,
plus the evidence of
the volcanic eruption
just 50,000 years ago,
I mean, now we cannot
say that Mars is dead.
We have to say Mars is active.
A volcanically active Mars
suggests its interior may
still be warm... if it is,
why did the planet's
magnetic field die?
Insight probes
deep into the interior of
the Red Planet using vibrations
from small Mars quakes.
Insight uses these to kind of
construct what the interior of
Mars was like,
because these waves
bounce off different layers
inside the interior of Mars
in different ways.
Insight's seismometer
builds a picture of Mars
by completely redrawing the map
of the interior of the planet.
It turns out
the crust is thinner
than we thought...
It's only 12 to 23 miles thick.
So there's this whole picture
of Mars that is unfolding in
front of us that is
vastly different
than we ever predicted.
Insight's new and improved
layout of Mars reveals
a 969-mile-deep mantle
surrounding a metal-rich core.
New analysis of data from
Insight reveals the size of
the core of Mars,
and we haven't had this before.
It's so exciting.
It's about 1,100 miles
in radius.
This is a little more than
half the radius of the body,
which is pretty big, and is
much bigger than we expected
for the size
of the core of Mars.
Mars's larger core
makes up about a quarter
of the planet's mass.
And Insight's journey to
the center of Mars
reveals another surprise.
We have always thought
that the core of Mars
was long since solidified
and wasn't warm at all.
And Insight is now showing us
that actually,
part of the core is probably
still molten,
which is shocking.
There's a liquid core at Mars.
I mean, this is crazy.
Data from past missions may help
explain why Mars's core
is still liquid.
Scientists discovered high
levels of sulfur in the crust.
Mars seems to have
a bit more sulfur,
at least in the surface,
than Earth does.
If we extend that composition
to the core
and add more sulfur to
the iron-nickel core,
that would actually reduce
its melting temperature,
making it possible for this
core to be molten today.
We thought that Mars
lost its magnetic field
when the core
cooled and solidified.
A molten core
changes everything.
Well, how can we explain
this lack of a magnetic field
at Mars even though
there's a liquid core?
Well, in order to have
a magnetic field,
you need the fluid to be moving
and rotating and convecting.
Over time, as Mars
lost heat and cooled down
its core stayed molten
thanks to the sulfur.
But, with less heat,
there was not enough
energy to power the churning
convection of liquid metal
that creates
an electric current.
The convection in that core
would have slowed down
to the point where no magnetic
field would be generated.
Mars's magnetic shield dies.
The solar wind's
relentless att*ck
strips the planet of
its atmosphere.
As the atmosphere disappears,
water on the surface
gradually boils away.
But did all of the planet's
water dissipate?
To find out,
our robots once again team up.
Since the first probe
visited Mars in 1971,
the Red Planet from orbit,
while 10 landers
have explored the surface.
They've revealed Mars may
still be an active planet,
one that once had the right
conditions for life.
Mars used to be
thought of as this dry,
arid, inhospitable environment.
And thanks to the recent
Mars missions,
we know now that they could
have sustained life.
Could there be any
ancient Martian
water left,
hidden inside the planet today?
MAVEN investigates by
analyzing Mars's atmosphere
for one of water's
components... hydrogen.
The MAVEN mission is looking at
hydrogen that's currently in
the Mars atmosphere.
This is a really important
thing to study.
The gas is produced when
the solar wind slams into Mars's
thin atmosphere
and smashes apart
molecules of water
into hydrogen and oxygen.
Hydrogen molecules
come in two forms...
Light, regular hydrogen
and the heavier deuterium.
The ratio of the different types
tells us about the history of
water on the Red Planet.
It turns out that it's much
easier to lose the lighter
version, because gravity
just you can't hold on to
something that's light as
easily as a heavier thing.
So we expect that,
as time goes on,
we'll have less and less
light hydrogen
and more and more
heavy hydrogen.
So if we can measure
the outflow of hydrogen from
the Martian atmosphere today,
and specifically, whether
it's light or heavy hydrogen,
we can start to get some kind
of idea about how much water
has been lost from Mars
and therefore how much might
still be there today.
analyze data from Mars's
rovers and orbiters
to discover the ratio of
deuterium to hydrogen
in the atmosphere.
They find less of the heavy
hydrogen than expected.
If Mars had lost a lot of
its original water
out into outer space,
we'd expect to find lots of
heavy hydrogen
left behind in the atmosphere.
But, in fact, what we found
was that the ratio
told us that Mars didn't lose
much of its water upwards.
And so maybe
the water went downwards.
Where is Mars's water hiding?
Some scientists
think it could be
stashed away
in the Martian rocks.
When we look at a rock,
we often think this is a really
dry thing,
there's no water in there.
But, in fact,
there's often a lot of water
in rocks, and it's because
it's bound up in minerals.
Changes in the crust can drive
these minerals to suck up huge
volumes of water,
equivalent to a global layer
over 300 feet deep.
Researchers estimate
that as much as 99 percent of
Mars's water could be locked
away below the surface.
And Mars hides water
in other ways, too.
Enter the European
Space Agency's orbiter,
Mars Express... probing one mile
beneath the Martian South Pole,
it finds a secret store
of water.
Really exciting.
We've discovered a system of
lakes beneath the Martian
polar ice caps,
lakes of what appears
to be liquid water.
Now, these lakes
are not very deep.
They're probably only
a couple of feet deep,
maybe in some places even
a couple of inches deep,
but they're quite large.
Some of these are
about 20 miles across.
And there's even some
suggestion that these are
connected with channels, kind of
a system of very shallow
great lakes near
the South Pole of Mars.
The Martian poles are
the coldest regions
on the planet.
Temperatures can
reach 200 degrees below zero.
So why is it that
underneath this cold ice,
you might even find
liquid water?
Well, remember,
you're actually going down
closer into the interior
of Mars there,
and so that's warm.
It's possible that
the geologic activity inside
Mars is warming the ice
from the underneath.
But heat from
the interior of Mars
wouldn't be enough to keep
these lakes liquid.
The secret ingredient
may be salt.
If you've ever spread
salt on an icy driveway,
you'll notice that where
the salt hits the driveway,
the ice begins to melt.
Saltwater actually freezes at
a much lower temperature
than water that's fresh.
So if it's salty water,
it could actually stay liquid
at lower temperatures.
We still aren't
are completely liquid.
Some scientists think they
could be lakes of frozen clay.
Until we have a rover that can
explore beneath the poles,
we won't know for sure.
The only real way we can tell
for sure is to send
some kind of mission that drills
right down through
that polar ice and samples
what we find at the bottom.
Wherever it may be hiding,
Mars's water is locked away,
but in its past, the planet had
impressive lakes and rivers.
Did they ever host life?
To find out, the rovers
take a deep dive into Mars.
Veteran crew member, Curiosity,
explores the Gale Crater.
The rover's mission?
To find evidence
of whether Mars could have
supported life.
Los Alamos National Laboratory.
Principal investigator
of Curiosity's
ChemCam, Nina Lanza,
works closely with the rover
patrolling Mars 34 million
miles away.
In many ways, Curiosity
is like my first child.
We had to take such good care
of her while she was still here
on Earth, but like all children,
she had to forge her own path.
And so we had to send her
on her way
to discover new things
on Mars by herself.
ChemCam uses
a precision laser that
analyzes the chemical
composition of Martian rocks.
We have a laser that
we focus onto a target
up to 23 feet away, and we
vaporize a little material,
and then we look at the light
made by this vaporized material
and figure out
what elements are in the rock.
Working with an instrument
like ChemCam is really
a childhood dream come true,
because I was always hoping
to work on a spaceship,
and today, I work on
a spaceship with lasers.
How cool is that?
With their
long-distance teamwork, Nina
and Curiosity discover rocks
with a shiny coating,
laced with manganese.
One of the most exciting
discoveries from Curiosity in
Gale Crater was the existence
of high concentrations
of an element called manganese,
and that's because manganese on
Earth is very closely tied
to life.
Could the manganese of Mars
be linked to life forms?
To investigate, scientists
look at similar coatings
called varnish on desert rocks
here on Earth.
So I have an example here
of some rock varnish,
and you can see,
it's actually incredibly dark.
It has a lot of iron oxide,
manganese oxide,
and clay minerals in them.
And the rocks can sometimes have
none of these things
in the rock itself.
So the question is, where does
this coating come from?
Often,
we find microbes associated
with the varnishes
and so possibly,
these microbes
actually helped fix
the manganese onto the surface.
The age of these Earth
varnishes may provide
a clue to Mars's
distant past... here,
they only appear after
a significant event in
our history...
The creation of
the oxygen we breathe.
A couple of billion years ago
on Earth was the great
oxygenation event.
Basically, the Earth's
atmosphere did not have
a lot of oxygen in it.
It was locked up in
minerals and chemicals.
Well, some bacteria discovered
how to photosynthesize light,
how to convert energy from
light into their metabolism.
And via the chemistry of this,
they wound up emitting oxygen.
The oxygen was poison
to many life forms,
so they d*ed out.
But others thrived, pumping more
and more oxygen
into the atmosphere.
Oxygen reacts with
the manganese,
binding it to the rocks.
We don't really see
these minerals until
after the rise of oxygen
in the atmosphere,
so after photosynthesis.
For Mars to have
these same manganese varnishes,
there must have once been
more oxygen
in the planet's atmosphere.
Is it possible
that Mars had a lot
of oxygen in its atmosphere
in the past,
and there were wee little
beasties processing it?
And so the search
continues, and Curiosity uses
another piece of equipment
to sniff out
traces of past Martian life.
One of the key instruments
aboard Curiosity is a piece of
lab kit called a gas
chromatography
mass spectrometer,
or GC-MS, and all this really
is, in essence, is, like,
a very sensitive
electronic nose.
Curiosity digs up some
Martian soil
and heats it
in its portable chem lab.
Like a robotic bloodhound,
it sniffs the vaporized dirt
and picks up
the faint smell of
a rare molecular compound.
What Curiosity discovered was
a compound called thiophene.
This is interesting,
because at least on Earth,
thiophene is often found
in fossil material, in coal,
in oil, as well as
stromatolites or micro fossils
of ancient life
in the fossil record.
So maybe this thiophene
we've now discovered on
Mars is some trace chemical
fossil of ancient Martian life.
Or possibly, it was produced
by non-biological processes.
Curiosity is knocking
on the door
of finding the evidence
for life on Mars.
We haven't found life,
but we've found the interesting
bits that are pieces of
the puzzle,
the organic puzzle of life
on Mars.
And so it's getting us to that
ultimate question, is there
or was there ever life
on the planet?
To help answer that question,
scientists bring in
pinch hitter, Perseverance.
The newest member of the crew
has the latest tech, tools
designed based on lessons from
previous missions.
Perseverance is so important,
because it leverages all of
the knowledge of the previous
rovers, which set the stage for
taking samples
on the surface of Mars,
searching for life, and setting
up a place for humans to
explore in the future.
Perseverance gathers
rock and soil samples,
testing some itself and leaving
others to be collected
and returned to Earth later.
We are just at the beginning of
the Perseverance mission.
We have so much to learn.
But I think all of us
would be so thrilled
if we could actually find
definitive signs of past
Martian life...
That would be incredible.
I don't know what form
that would take,
but we're going to look for it
in every way that we know how.
While Perseverance
hunts for evidence
of ancient life on Mars,
Curiosity detects
hints that life may
exist on the Red Planet now.
In Gale Crater,
Curiosity detects
a huge surge of methane gas.
The methane we've
detected in the atmosphere of
Mars is potentially very,
very exciting.
Most of the methane
in our own air,
in Earth's atmosphere,
is biogenic.
It was released
by living organisms.
Curiosity's result
is exciting, because we know
that this can't be
ancient methane.
Methane is really interesting,
because it has a short
residency time in an atmosphere,
which means it breaks down
very quickly.
Whatever is making methane
in Gale Crater
is doing it right now.
Curiosity has detected
methane many times before.
But this is the largest
amount so far.
The question is,
what created it?
Maybe this Martian methane is
the first trace we found of
Martian life,
micro organisms living
deep underground.
Or maybe that methane is
not biological, but geological.
It's methane that's been given
off by volcanic processes in
the past.
The frustration is,
we can't quite tell
the difference
between the two just yet.
All we can do is continue
to sniff
the air and document
when and where we see it.
The picture becomes more
intriguing when Curiosity
detects oxygen in greater
quantities than expected.
There's a lot more oxygen on
Mars than we had suspected,
which is weird
in the first place.
And the amount of oxygen
is changing seasonally.
There's something in or on Mars
that is adding oxygen
to the Martian atmosphere
during the spring and summer
and then taking it away during
the fall and winter.
There is something that is
actively controlling
the amount of oxygen in
the Martian atmosphere.
What is that?
Most of Earth's oxygen
comes from living organisms
photosynthesizing, and it
changes with the seasons.
We have normal,
cyclical, seasonal variations in
the amount of oxygen here
on Earth because of life.
The most landmass on the Earth
is located in
the Northern Hemisphere.
And so that means that during
northern summer,
most of the oxygen
on Earth is generated.
So there's a peak in oxygen
during the northern summer.
So where is the oxygen
on Mars coming from?
Oxygen is a known result of
life of photosynthesis.
It's a biosignature.
It's a sign of life.
Is this a sign of life on Mars?
The atmospheric
changes in oxygen
and methane are
a fascinating puzzle
and a tantalizing hint of life.
Life on Mars
explaining these changes in
methane and oxygen would be
incredibly interesting.
So it's probably wrong.
The answer is probably more
boring, and not that chemistry
is boring, but it's...
It's a little less
interesting than life.
We Mars scientists, of course,
are always very excited
about seeing signs of maybe
extent life on Mars,
but we're going to require
really big proof before we feel
truly excited that
we've made this discovery.
The army of robotic
explorers continues
to rewrite the story of Mars,
discovering a once warm,
wet world
with the potential for life.
Now, a new generation of robots
led by Perseverance will dig
deeper into the Red Planet's
troubled past
and its frozen present
and maybe hit the mother lode,
life itself.
With every new mission to Mars,
I hope that somebody really is
going to find evidence
that life either existed there
in the past or maybe even
still does now.
And with all of these missions
on many places on this planet,
maybe now is the best time to
actually answer that question.
Whether or not it's likely
that Perseverance finds life
on Mars,
we have set ourselves up
for success, and I am
so hopeful that we get to
finally answer that question,
the big question.
Are we alone?
11x02 - A Robot's Guide to Mars
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Science documentary television series that provides scientific explanations about the inner workings of the universe and everything it encompasses.
Science documentary television series that provides scientific explanations about the inner workings of the universe and everything it encompasses.