Original subtitles

3.7 billion years ago,

early life was on the brink of extinction.

Colossal impacts...

Ferocious climate change...

And total atmospheric collapse have turned paradise into hell.

But this isn't Earth...

It's Mars...

And this is the violent history of perhaps

the first life forms in our solar system.

Could these martians still exist today?

Could they even be living among us?

scientists suspect that life may once have thrived on Mars...

That the barren world we see today

swarmed with martians long ago.

If I had to bet something incredibly valuable to me...

If I had to bet my car... On whether or not

there's life on Mars,

or evidence of past life on Mars,

I'd take that bet.

The building blocks for life

are widespread in the universe,

and early Mars could have been the perfect place

to pull these ingredients together.

If you had a recipe book for everything you need for life,

you'd have things like water, organic chemistry,

a stable surface, a thick atmosphere...

Well, Mars had all of those.

Mars satisfies every specific requirement

for letting life get started.

Life on Mars

may have been inevitable,

and we've sent a robot army to hunt for signs of it.

But so far, it's been elusive.

Our rovers, landers, and satellites

haven't found life yet,

but they have found evidence of something extraordinary.

Mars was the victim of a devastating series

of extinction-level events

that rocked the red planet to its core...

Leading us to wonder,

if life could have started over multiple times,

with generation after generation of martians

rising and falling through Mars' violent history.

It seems likely that a first Genesis of life

could have occurred very early on in Mars' history,

just as soon as the crust was cool enough

to give it a solid foothold.

The secret to this early life would have been

a crucial ingredient, one shared by the young Earth.

Dry, harsh Mars once had oceans.

For life to get started,

you need some carbon, an energy source,

it needs nutrients like nitrogen...

But those are likely to be present on Mars,

they are present and widespread on Earth.

The essential requirement is really the liquid water.

Picture Mars

4.5 billion years ago.

Molten rock has cooled to form a solid crust.

Water collects on the surface, forming primitive oceans.

Rain clouds sweep across

the steaming, volcanic landscape,

and in shallow pools of water,

the martians begin to emerge.

But these first aliens are simpler

than Sci-Fi would have us believe.

We're probably not talking about little green men

or women, or whoever.

Walking around on the surface of Mars, we...

We're talking about something probably

much, much smaller and simpler,

single-celled life.

If would look familiar,

it would look just like bacteria on Earth.

Little, tiny, round, rod-shaped organisms.

If this generation

of bacterial martian life really did exist,

it was the first life to grace our solar system.

Multiplying inside the rock pools of Mars

long before life took hold on Earth,

Mars' small size would've given it a head start.

Because Mars is smaller

than the Earth it would have cooled

a little bit faster than we did.

So early on in the life of the solar system,

Mars may have been more like Earth

than Earth was at the time.

Let's go back 100 million years

after the sun formed.

The surface of the Earth is still a molten lake.

But martian life could be thriving

on the smaller, cooler world.

But these first martians won't have long

to enjoy their time in the sun.

Inescapable death is already on its way from space...

A cosmic bomb so huge,

it would completely alter the shape of the planet,

leaving it lopsided,

the northern hemisphere crushed.

Most planets are round,

and that's just something you don't really

give much thought to,

but it turns out Mars isn't as round as it could be.

The Southern hemisphere, on average,

has a higher elevation than the northern hemisphere.

So, in other words, if you were to start on the north pole

and walk all the way around to the south pole,

you'd be walking uphill, essentially, the whole time.

So, we call this difference between the northern

and the Southern hemisphere,

we call this the crustal dichotomy on Mars,

and it's been one of the biggest mysteries of the planet,

you know, it's the first thing that you see about it,

and you say, well, how could this possibly have happened?

In 2008, scientists mapping

the surface of Mars came up with an explanation

for the massive dent in the planet, shown in blue.

This basin, the biggest in the solar system,

had to be the result of a massive impact.

Called the Borealis impact,

it blasted out a crater 6500 miles wide and five miles deep,

big enough to swallow the entire United States

with room to spare.

Something really big happened.

In fact, the entire top half of the planet

seems to have practically been blown off.

The only thing that could do that is a huge collision,

and we're talking a collision

with something the size of Pluto, perhaps.

You're talking about an impact

that makes the dinosaur killer impact

65 million years ago look pretty much like a wet firecracker.

4.5 billion years ago,

the early solar system is filled

with planetesimals and protoplanets...

Asteroid-like leftovers from a planet building process

that created Mars and the Earth.

One of these asteroids is huge,

and it's on a direct collision course with Mars.

Any microscopic martians have just seconds to live.

If this impact was happening today

and we were so unlucky as to be there to witness it,

what you first would have seen is another moon in the sky...

And then you would've looked back and seen,

oh, it's getting bigger.

As it came down it would have filled the entire sky,

from horizon to horizon,

and as it struck,

the top would have still been well out into space.

The impactor

is 1200 miles across,

the size of Pluto,

and as it hits, the energy of the impact

shakes Mars to its core.

The entire planet wobbles like jell-o.

As it came down,

it would have been hitting into the surface of Mars

as fast as a bullet out of a gun,

and it would have slammed into the surface

and sent a shockwave out

that would've been bigger than any earthquake ever recorded.

It would have been like a Tsunami of rock

coming out and tossing us out of the way.

The impact is catastrophic.

It blows nearly half the planet's surface into space

and turns what crust remains into a boiling lake of lava.

You can't have an impact of that scale

without almost melting the planet.

It's not literally a planet breaking event,

but it's a planet melting event,

and it is, it is the sterilization

of the planet at that point.

The surface of Mars was molten,

its atmosphere blown into space,

the oceans boiled away.

If Mars was home to the first generation of life

in our solar system,

that life didn't stand a chance.

It would take the surface of Mars 50 million years

to recover from the impact.

But what sort of planet will rise from the ashes?

Compelling new evidence suggests that the conditions for life

may have returned to Mars,

but did life itself make a comeback?

This impact was only a blip in time,

and there was possibilities for life

and the planet to recover.

4.5 billion years ago

an asteroid the size of Pluto

slammed into the surface of infant Mars.

It melted the surface of the planet,

it blew the atmosphere into space,

and it boiled away the oceans.

If life had gotten a foothold on the planet,

that life would have been completely exterminated.

But some scientists believe this extinction

could have been brief,

and that life could have started again from scratch.

One of the wonderful things

to imagine is that there probably wasn't

a single origin of life.

It's not like it happened once

and then everything just went from there.

Maybe there were multiple times that life got started

and went extinct.

Ten million years

after the Borealis impact

crushed the planet's northern hemisphere,

Mars has cooled enough for its surface

to become solid once more.

The planet has some of the ingredients for life...

The right molecules, a stable surface,

and an energy source.

But something's missing.

4.49 billion years ago the surface of Mars was dry,

and without water, life can't start over

and a second generation of martian can never arise.

As far as we know life,

water is absolutely, fundamentally important to life.

2004... NASA's opportunity rover

lands on Mars.

Part of its mission is to search for evidence

that water returned to Mars after the Borealis impact.

It's not long before opportunity

stumbles across something strange on the surface

of a fossilized sand dune...

Bizarre, round, metallic rocks.

These rocks are called blueberries,

and they're an important find for planetary geologists,

like Jani Radebaugh,

because fossilized sand dunes also exist on Earth.

And Utah's petrified dunes

are also littered with blueberries.

This is really exciting

because we've seen the exact same thing on Mars.

Finding blueberries on Mars

is significant, because the Borealis impact

melted the planet,

so anything found on Mars today

must have formed after the impact.

But crucially, these nodules of iron oxide

formed deep underground and in the presence of water.

In order to form one of these little blueberries,

there needs to be huge amounts of water

flushing down through the fossil sand dunes,

and as it does that,

it carries with it all of the iron oxides

around each sand grain.

And just one tiny, little one like this...

Now, this is maybe about

an ounce of iron, maybe a little bit more...

And in order to get an ounce of iron

to concentrate into this blueberry,

you need to have a thousand gallons of water.

Blueberries form

deep inside sandstone.

But over thousands of years,

wind erosion blows away the softer rock,

leaving just the blueberries behind.

If we walk to the edge of this

pile of blueberries,

we could see the process by which

they're actually eroding out of the rock.

The blueberries right here contain

within this fossil sandstone layer.

The winds are blowing in this direction,

down the layers,

and they're actually eroding out the soft sandstones right here

and leaving behind very dense iron nodules,

and as they pluck themselves out of the rock,

they roll down the hill and they collect...

Right here, in between layers.

We know we found conditions just like this on Mars.

We have fossil sand dune layers,

we also have blueberries all over the surface,

so we know the same kinds of things

had to have happened on Mars that have happened here.

There has to be water flowing through the rock,

gathering iron,

and then there has to be a huge amount of wind

to strip away the fossil sand dunes.

For blueberries to exist

on the surface of Mars today,

the red planet must have gotten its water

and its atmosphere back after the catastrophic impact.

With liquid water on the surface,

the ingredients of life might have combined, once again,

to create a second generation of martians.

But where did this water come from?

The answer is surprising.

It could have been in the planet itself...

Water is incredibly abundant.

We know that there's water deep,

deep, deep in the Earth's mantle,

and so it's entirely possible that on Mars

there was water so deep in the planet

that even after this catastrophe, it came back up.

On the Earth, scientists

diffuse the seismic waves of earthquakes

to detect an ocean's worth of water

chemically embedded in minerals deep underground.

A similar water source could have been hidden

hundreds of miles below post-impact Mars,

and volcanoes could have brought that water back to the surface.

One way for water to get from

deep underneath the surface to the surface of the planet

would be through geologic activities...

Volcanoes, for example.

We know that volcanoes spew out a lot of gasses on Earth,

including water vapor,

and we see volcanoes on Mars.

Mars is home to the largest

volcanoes in the solar system.

The biggest of all, Olympus Mons,

is over three times taller than mount Everest.

4.49 billion years ago volcanoes spew lava spiked with water

into the atmosphere and create ferocious rainstorms

that flood the surface of Mars.

Over tens of thousands of years

Mars becomes a watery world once again

with the perfect conditions for a second generation

of martians to rise up.

It would seem that

when you have a massive collision,

like what happened to Mars,

it would be game over for life.

But there's something more complicated going on.

Maybe that asteroid impact kicked off

an entirely new cycle of life on Mars.

In theory,

four billion years ago,

a second generation of single-cell bacterial life

arose on Mars,

and for the very first time there was life

on two planets in the solar system.

140 million miles away, life on Earth had just begun,

and thanks to Earth's stable climate,

it would one day evolve into us.

But the outlook for Mars was very different.

Evidence from the Mars reconnaissance orbiter

suggests an icy apocalypse was about to strike.

For Mars' second generation, winter was coming.

Four billion years ago,

the first life has arisen on Earth,

but on Mars, life may be starting out for a second time.

It's possible that Mars

had life before Earth did... It got wiped out...

And then got started again by rehydrating the planet.

A planetary collision

has blown away Mars' atmosphere and oceans,

along with any life,

but giant volcanoes have brought water back to the surface

from deep within the planet.

This could have allowed

for a second generation of life to rise up.

But these martians are about to be tested to their limits

by catastrophic climate change.

2008... NASA's Mars reconnaissance orbiter

flies high over the surface of Mars.

Its ground-penetrating instruments

peer deep below the surface,

aiming to unlock Mars' geological secrets.

As it scans near Mars' equator,

the orbiter spots something that has no right to be there...

A vast, underground glacier.

One mile thick and three times the size of Los Angeles,

ice on this scale should only form at the frigid poles.

The only explanation...

Mars must have been tipped over

with its equator tilted away from the sun.

The tilt on Mars' axis

has actually changed significantly over time,

and in non-systematic ways,

it just happens randomly that it will start moving,

and so there are some models that suggest

that Mars has actually been almost tipped over on its end.

Most planets wobble,

and from time to time, they wobble so much

they can tip over, leading to super winters.

If that had happened here on Earth,

Los Angeles could become the arctic.

Well, you can imagine something similar would happen on Mars,

how drastic the change would be.

You're used to seeing the sun overhead,

it's very warm, there's probably liquid water,

and as the planet starts going this way,

the sun is not gonna rise as high in the sky.

Eventually you may not see sunrise for half a year,

and any water that's there is gonna be frozen solid.

3.9 billion years ago,

Mars is tilting by as much as 80 degrees.

Winter temperatures drop below minus 125 degrees Fahrenheit.

As the polar ice sheet spreads quickly toward the equator,

liquid water is frozen solid,

along with any potential martians.

The water that drives the biochemistry of life

freezes inside the tiny bacteria.

Ice crystals form and puncture the martian's cell walls

until eventually, they die.

Every 120,000 years the tilt of Mars changes,

as again and again the planet's chaotic wobble

flips the martians in and out of the deep freeze.

Any second generation of life on Mars...

Is left in tatters.

Meanwhile, on Earth, our ancient ancestors have it easy.

The Earth's wobble, and its seasons, stay relatively stable,

and it's all thanks to our secret weapon...

Our oversized moon.

The interaction of our planet and the moon

means that the axis of our rotation is very, very stable.

The seasons return year after year, century after century,

for billions of years.

Our moon's enormous mass

exerts a huge gravitational pull on the Earth,

stabilizing the wobble of our planet

and keeping our climate in check.

Without the moon, the early Earth

would have wobbled just as wildly as Mars,

and our ancestors could have faced the same icy fate

as the early martians.

Mars doesn't have a big moon,

it has two, little, tiny moons

that don't really affect it much.

So if the martians were killed

the first time by a giant impact,

they may have been killed a second time

by Mars itself not being stable and flipping over

and having catastrophic super winters and super summers,

basically, mega catastrophic climate change.

On Mars, the outlook for life

seems bleak.

But the brutal conditions that drive martian life

to the edge of extinction may also have pushed it

to adapt and evolve.

We know this because on Earth organisms known as extremophiles

have evolved to live in the most severe of circumstances,

from boiling, hydro-thermal vents...

To the deep freeze of glacial ice.

When the going gets tough, life seems to get tougher.

Maybe the martian super winters

gave rise to a third generation of life...

A super tough army of bugs able to survive

the harshest of climate swings.

What we see on Earth is that life evolves

to occupy whatever niche it lives in,

and that evolution takes time.

So as the environment changes, life changes with it.

If there are sudden changes,

then life forms can't cope with it and many die away.

Those that survive, they continue on.

3.8 billion years ago

a third generation of life could have thrived

on the surface of Mars.

Evolved from a handful of its predecessors

to make it through Mars' super winters,

it's the toughest martian life yet.

But, as the super winters end,

the challenges for life on Mars are set to get worse.

Another extinction-level event is on the way.

Mars' atmosphere is being ripped away molecule by molecule.

Could this be the killer punch

that wipes out the martians for good?

Narrator: Imagine Mars

3.8 billion years ago.

It's a warm, wet world,

and super tough bacterial life is thriving.

But these martians are not the planet's first inhabitants.

The first generation of martian is vaporized

by the huge Borealis impact.

Perhaps life starts over from scratch,

but endures a series of extreme climate swings.

Only the toughest martians make it through.

But another disaster is about to strike,

and this catastrophe will test even the strongest martians.

They're about to lose the most basic ingredient of life...

Liquid water.

You really have to appreciate how difficult it is

to have liquid water on the surface of a planet.

We know that life works so well

when there's liquid water around.

But you need just the right balance

of air pressure and temperature.

Without air pressure

weighing down on it,

liquid water will evaporate from the surface of a planet,

whatever the temperature.

That air pressure is generated

by the presence of an atmosphere.

In a lot of ways that atmosphere

serves as a kind of a lid

stopping down the water from escaping into space.

It's very important to have that atmosphere.

3.7 billion years ago,

life on Earth enjoys warm oceans and a thick atmosphere.

But on Mars, a third extinction-level event

is gaining momentum.

The atmosphere is slowly being stripped away,

and Mars' great oceans are starting to evaporate.

The fate of life on both planets

now rests on the strength of their magnetic cores.

It turns out that the existence

of an atmosphere on Earth may rely on the magnetic field,

because what our magnetic field does

is it protects us from the onslaught of this wind,

of subatomic particles

that the sun is blowing out all the time.

We call this the solar wind.

And if we didn't have a magnetic field

to basically catch and deflect those particles gently,

they would directly slam into the Earth's atmosphere.

If you think of the magnetic field

as a windbreaker from the solar winds,

once we lose that protection,

that planet becomes very vulnerable.

The Earth's magnetic core

has stayed strong for 3.45 billion years

as super hot molten iron churns over and over

within the planet like a lava lamp.

Churning iron creates electricity,

which in turn generates a magnetic field

that rises up around the Earth, acting like a magnetic shield,

protecting our atmosphere from the ravages of the solar wind.

3.8 billion years ago

Mars had a molten core and a magnetic field.

But something caused its shield to drop.

Did Mars' small molten core simply get too cold to function?

Or did something else kickstart

this third great extinction of martian life?

A new and controversial theory points the finger

partly at the ancient Borealis impact.

A giant impact of this scale

can affect a range of temperatures,

from the hot inner core to the cooler outer mantle.

4.5 billion years ago

the impact that vaporizes

the first generation of martian life

also drives heat into the planet,

increasing the temperatures in the outer mantle.

The heat inside the planet evens out,

and the metals slowly stop churning.

But there's less of a temperature gradient...

That makes it harder for this dyno process to,

to drive a strong magnetic field.

Over hundreds of millions

of years, Mars' magnetic field shuts down.

When Mars lost its magnetic

field all of a sudden

it was completely vulnerable to the solar wind.

The solar wind could break apart

and carry away the martian atmosphere.

3.7 billion years ago

super tough martian life faces annihilation.

Bit by bits, the atmosphere is being swept into space.

The air pressure is dropping across the planet

and most of Mars' water has already boiled away.

The chances of survival

without this precious liquid are remote.

But, for the martians, there's an even more immediate danger.

With no magnetic field and no thick atmosphere,

the surface of Mars feels the full force

of the sun's radiation.

If you're a microbe

on the surface,

you would have to make do

with very little atmosphere, no water,

this flood of ultraviolet light from the sun,

and these particles which are slamming into you all the time.

The martians are bombarded

by radiation from the solar wind.

It rips their DNA apart.

Without an atmosphere,

the surface of the planet is sterilized.

But is this really the end for martian life?

Life is so tenacious,

it can survive even those incredible catastrophic changes,

and it may still be there today.

To survive the radiation,

martian life would have had to have moved deep underground.

In this protected subterranean environment

it may also have found a source of liquid water,

and if that happened,

could the martians still be there today,

waiting for us to drop in and say hello?

Since the 1960s

robotic probes and landers

have been searching the surface of Mars for signs of life.

But have they been looking in the right places?

The surface of Mars is a waterless desert

that's bombarded by harmful radiation.

If a fourth incarnation of martian life is alive today,

many scientists think it'll have to be deep underground.

Underneath the surface of Mars

you may have all the conditions you need for life.

There may be some liquid water down there,

and you're also protected from the intense radiation

that you find on the surface.

Scientists are split

on the best underground places to search for martian life.

But if Jani Radebaugh were on Mars,

she would head to the nearest sand dune and start digging.

Here you can see

this is wet sand just below the surface.

This is the perfect environment to be able to house life.

Even in the very driest deserts on Earth,

in between the sand dunes, in the inter-dunes,

you can find water percolating up from Springs

that come up from deep under the ground,

perfect for life to form and grow.

And if you just keep on digging...

Down into the bottom of the inter-dune,

maybe you would reach the water table.

And if you reach the water table on Mars,

now you have all the conditions just right for life.

This is my bet, this is where I'd go,

right between the dunes.

Digging for martian life

in the desert is one option.

But some scientists have very different ideas,

and planetary scientist Nina lanza

would need to pack a rope and a flashlight for her search.

So if were to go to Mars to find life,

I would go to a lava tube.

Lava tubes are made

by ancient volcanoes,

the empty leftovers from underground lava flows.

Today, they form deep tunnels,

shielded from radiation and shut off

from the harsh martian climate.

We've never been

in a lava tube on Mars,

but it is absolutely possible that there's liquid water.

So, that's an environment where you could have some moisture,

you could have a little warmth, you're protected from radiation.

I think that a martian microbe would be very happy there.

Finding life on Mars

would be a monumental human accomplishment.

But there is a danger.

By exposing martian life to life from Earth,

could we unwittingly set off yet another extinction event?

Humans have been

one of the most effective extinction mechanisms

of life on Earth.

The interesting question will be,

will we produce a similar calamity on Mars?

If humans someday go to Mars,

then we will be an invasive species,

and if there is some martian life

that's hanging on in some niche,

we could be their ultimate destroyers.

So we have an ethical responsibility

to preserve whatever life may be on Mars.

The problem isn't us,

it's the bugs in and on our bodies.

The average human has

ten to 20 trillion bacterial hitchhikers.

If we go to Mars,

we'll be taking our tiny companions along for the ride,

and any one of those bugs could turn out to be

a deadly competitor for martian life.

It's NASA engineer Moogega Cooper's

job to keep Mars rovers bug-free.

But keeping astronauts clean, that's a whole different matter.

We bake our spacecraft hardware

at 110 degrees Celsius for at least 50 hours

to prevent the contamination of Mars.

But unlike spacecraft, we cannot bake humans out.

We will not survive those temperatures.

Unless we find a way

to keep astronauts bug-free,

exploring Mars with robots is our best option

for keeping the martians safe from harm.

But what will happen when our robots

finally find that life and we look deep into the workings

of our extraterrestrial neighbors?

What will the martians turn out to be like?

Our example where DNA is the organic molecule

that carries the information of life...

We don't even know

if that's gonna be the rulebook in other places.

Finding any evidence whatsoever on Mars

would help us better understand what else is possible.

Will the martians

be different than us?

Made from different materials

and with a different biochemistry?

Or will they seem shockingly familiar?

Some scientists think that the very first martian life

may not have stayed on Mars.

It may have come here.

It's not that farfetched to think

that life could have jumped from Mars

or been a back and forth from Mars to Earth.

If the martians came to Earth,

could they have seeded life on our planet?

Maybe the martians aren't dead.

Maybe I'm a martian, maybe you're a martian.

We've sent a robot army to Mars,

and what it's found is astonishing.

The possibility that life could have arisen there,

perhaps more than once,

with different generations of martians emerging from the ashes

of catastrophic extinction events.

Life could still be sheltering

below the surface of Mars right now.

But there's another possibility that's truly astounding...

That martians aren't just hiding out on Mars,

they're thriving, right here on Earth.

I might be a martian,

you might be a martian.

We might be from another planet.

We might have already travelled and lived on two planets

as life forms... Not as a species, certainly,

but our ancestors may have come from another planet,

and that is mind blowing.

The idea that our ancestors

could be martians is a new take on an old theory

called Panspermia.

According to the theory,

life on Earth began when a space rock

filled with alien bacteria landed on the Earth

and every living thing we see today, including us,

evolved from those cosmic hitchhikers.

The idea of Panspermia has been around for centuries,

but had a resurgence when scientists

determined that life on Earth may go back four billion years,

to the end of a sustained attack of asteroid showers

known as the late heavy bombardment.

There are a lot of objects from the outer solar system...

Comets and asteroids, all kinds of things...

Coming into the inner solar system

and slamming into the planets.

Conventional wisdom

suggests the objects hitting the Earth at the time

were leftover debris

from the formation of the solar system.

But a very controversial idea

suggests these space rocks were actually all pieces of Mars,

thrown off in the Borealis space impact

when a huge object blasted into Mars.

The timing links up really well for the Borealis space impact.

If you calculate how much debris

that would have been thrown out into space

and when it would have had to have happened,

according to the martian geologic record,

it coincides with the late heavy bombardment...

It's possible that the debris

from the Borealis space in forming impact

might have come to Earth and rained down on us

and made the late heavy bombardment,

seeding the Earth with bacterial spores from Mars.

Now, this is just a hypothesis, we don't know this for certain,

we don't have evidence.

But it is physically possible for that to have happened.

Was the Earth seeded

by microscopic martians

blown into space by the Borealis impact?

It sounds crazy, but the science stacks up.

We know that simple life is tough,

able to survive in the cold vacuum of space,

and the timing of the Borealis impact

works out well for the rise of the first organisms on Earth.

Crucially, we know that rocks ejected from Mars

can make it all the way to Earth

because they're still crash landing here, even today.

One of the coolest things I've done as a scientist

is held a piece of Mars in my hands.

Now, we never had a mission that returned a sample from Mars,

we had to come about it a different way.

And it turns out we have meteorites

that we are 100% sure are bits of Mars.

They were actually exploded out during huge collisions,

and eventually they fell on the Earth.

Four different generations

of martians, each of them facing

a different planetary catastrophe.

But despite enormous odds,

martians could still be alive today,

buried deep under the surface of Mars,

or maybe even thriving on Earth.

If life is really that tenacious

that it can come back and keep coming back

and keep coming back,

that gives me a lot of hope for life in the universe.

That tells me that life is maybe tough,

maybe individuals are fragile, but maybe life itself is tough.

For now,

all we can do is speculate

until future generations develop the technology

to visit the red planet

and grab our first sample of extraterrestrial life.

That's going to change everything.

We're going to have another example

of how life started and how life works.

And even if it's something that's dead,

we knew it was there.

The universe will never be the same again.