I'm gonna tell you about the most incredible place.
It might be the weirdest place in the whole universe...
Full of liquid rock, crystal caves and alien landscapes...
And you know what?
You're walking on it.
We think we know our home, but once you've seen it from space it hits you...
I really wish that everyone could see the world the way that I've had
a chance to see it.
First you look at it and really are wondering what it even is that you're seeing.
Just like I lived my whole live in a semi dark room and somebody
flipped on the lights.
A living, breathing, working planet.
It's all just so wonderfully unlikely, and yet it's here.
Eight astronauts, with over 1,000 days in space between them,
can tell us how being up there...
Helped them to truly understand what goes on down here.
The weird connections.
The near misses.
The lucky breaks.
That built our amazing world.
The strangest place in the whole universe might just be right here.
Oh, you ready this morning, huh?
Here you go.
Let's have some fun.
There you go.
We take Earth for granted.
Come on, come on.
Come on.
We take so much for granted.
Hey, come on.
In fact, there's one thing that comes so naturally we don't even think about it.
Breathing.
Yes, come on.
Come on, come on.
But if you knew even half of what it takes to make the oxygen we need,
it would take your breath away.
You wanna know about breathing?
Ask this guy.
My first spacewalk, holding on to the outside of the spaceship,
with nothing except the sound of my own breathing.
In my one hand is my entire link with my own history.
Everything that's human, every story that's going on down on the surface of the world,
everybody I've ever met, with the whole universe in the other direction.
And then...
I let go.
That's when you really appreciate the significance
of that thin blue line.
It contains everything that's important to us.
It contains life.
And then Houston called to get back to work, I grabbed back onto the handrail
but while I was working, suddenly...
I had a searing pain in my left eye.
Like somebody had just stabbed me.
My eye just snapped shut and it started tearing up.
But the trouble is, without gravity tears don't fall.
The tear just gets bigger and bigger.
It got big enough that it became a little lake of water that went across the
bridge of my nose...
Into my other eye.
So I call down to Houston, "Houston, I'm having a problem here.
I can't see.
I'm blinded in both eyes."
"What did he just say? He's blind?"
Houston looked at what all the symptoms were and said...
"Maybe it's the worst-case problem.
You may have contamination in your suit."
"And you're gonna have to flush it out."
I reached up, turned this little valve, popped it and suddenly could hear,
"Ssssss, sssss".
As my precious supply of oxygen hissed out into the empty vacuum of space.
There is nothing more natural than breathing.
Yet as far as we know, this is the only planet where that happens.
The only planet with an oxygen-rich environment.
Without that, life would be something very different indeed.
? ?
This is Felipe's favorite place.
Even though the air is toxic.
The ground spits acid, and there is no fresh water.
No birds sing here.
No insects fly.
No plants grow.
It's hard to imagine anywhere less inviting...
But Felipe has found one thing that calls this hellhole home.
And it doesn't use oxygen.
It lives in a lake of acid.
? ?
It's hard to imagine sometimes just how important oxygen is to us,
as the way to release energy.
Every time I breathe in, oxygen-rich air mixes with the food I've eaten
and creates energy.
Power that enables larger, more complex creatures to exist.
Our planet is literally bursting with life, so how on earth is there
enough oxygen for everyone?
The answer takes in some pretty surprising stuff.
Giant dust storms, tiny snowflakes, flying rivers;
and the most important living thing you've never heard of.
But it begins in a desert.
A desert made of salt.
? ?
The people here rely on this desert and so do we.
But not because of the salt.
? ?
Dust storms can be pretty amazing when you see them from space.
And sometimes they're huge.
You know, I had seen little dust storms blowing and you kinda look hard.
This you didn't need to look hard.
It was a continent of Northern Africa basically obscured by thick brown dust.
And as I orbited, I couldn't wait to come back.
And then when I did, I saw that dust storm that was over Africa now
over the Atlantic Ocean.
And my next orbit I see it hitting the coast of South America.
Every year about 27 million tons of that African dust we can see
from orbit drops out of the sky into the Amazon Basin.
And it turns out, it's the perfect fertilizer.
? ?
And as they grow, the plants and the trees turn carbon dioxide into oxygen.
One single tree can produce enough oxygen to support two people.
And the Amazon Rainforest...
Is ten times the size of Texas,
producing 20 times more oxygen than all the
people on the surface of the Earth could consume.
But, not one breath of it leaves the Amazon.
There are so many animals living in the Amazon Basin that the life there uses all
that oxygen up.
For all these years I've been thinking the rainforest is the lungs
of the planet.
Now sure, it makes a lot of oxygen, but it uses it all.
The rainforest does help us breathe, but not because of air.
There's a river in the Amazon, no, not that one, there's another river,
a river in the sky.
For the most part, I know this world from standing on its surface.
I mean, I've been up to the top of the Empire State Building,
put my quarter in the scope, and I've even jumped out of planes a couple times.
But that's nothing.
The International Space Station clocks in at 1 million feet.
Whenever there's a free moment on the spaceship, we try and get to the window
to take pictures.
And during my three space flights, I took about 45,000 photographs.
And some parts of the world are easy to take pictures of...
Like the outback of Australia.
It's always a sunny day there.
But there are parts of the world that you almost never get a good picture of.
One of those is the Amazon Basin.
So it makes ya think...
What's going on down there?
? ?
For the last ten years, Rosa has been working in the Amazon,
uncovering the surprising way the rainforest helps the whole planet breathe.
She's not kidding about special.
This is the tallest structure in all South America.
Rosa has tried to climb this tower twice before,
but she's never made it to the top.
? ?
Now that's a pretty cool climb, but something else is rising too.
If you could look inside the trees...
You'd see water sucked up from the forest floor.
? ?
When the water hits the top, the combination of sun and wind...
Turns it into a mighty river.
A flying river.
This river of cloud flows across South America,
obscuring everything beneath it...
Until it runs into a brick wall.
5,500 miles long and up to 4 miles high.
The Andes.
The clouds condense into raindrops, which then race down the slopes and
flow directly back into the Amazon Basin...
Eroding the rock and turning it into sediment...
Until all those nutrients are dumped into the ocean and a whole other world.
And waiting for those sediments is an extraordinary organism,
four times thinner than a human hair.
It's called a diatom.
Diatoms are the secret to the Earth's oxygen supply.
They use silica from the ground up rock to create new shells,
which allows them to reproduce.
Their population doubles every day...
And they begin to photosynthesize...
Each one starting to produce oxygen.
Take a breath.
Now take another.
Now think about this:
one of those breaths was entirely provided by
those little fellas under the sea.
Looking at the oceans from space, sometimes you see a local area that's
an entirely different color.
And amazingly enough, what you're looking at is microscopic life.
Diatom blooms that reflect the light differently, so that they show up from space.
Biggest one I think I ever saw was huge.
It covered hundreds of miles.
You know, when you swim in the ocean
you don't notice the diatoms around you.
But when you're in space, you see the vibrant colors of life.
It's just so stunning, the blues and the greens.
But also, like, wow, those things are keeping us alive.
But you know what?
Diatoms are important not just because of what they do when they're alive,
but also what they do once they're dead.
I spent 166 days off the world.
Underneath you, the planet is silently,
intimately revealing itself to you,
more and more, every single time around.
And from a spaceship, Earth is definitely the Blue Planet.
And pretty much everywhere that there's water, there's diatoms.
There are trillions of them in every ocean,
and they can't all rely on flying rivers.
So diatoms around the world have to get their nutrients in different ways.
Some about as far away from tropical rainforests as you can get.
Okay guys, off you go.
Okay, yeah, slow down...
You can stop right there, yeah.
Okay.
These glaciers are unusual.
They can slide in sudden spurts.
Still too slow to see in real time, but fast enough to hear...
if you know how to listen.
Sometimes they move 300 times faster than their normal glacial pace.
Heidi can hear them crushing a huge amount of rock, as they grind their way
down the valley.
And when ice meets sea, it makes a familiar sound.
The popping is a heads up for the team.
The ice face is about to crash.
I'm hearing increased activity, you need to come back, okay?
Wow!
? ?
Diatom dinner time.
Now sometimes these glaciers move really fast, dumping tons and tons of
nutrients into the sea.
Boom!
Sparking a feeding frenzy and a population explosion.
But then, just as quickly as it started, dinner time is over.
The glaciers come to a grinding halt and lie dormant, sometimes for decades.
Boom becomes bust.
When the nutrients run out, the blooms fade and most of the diatoms die.
Their carcasses slowly fall to the ocean floor...
Where they carpet it in a layer half a mile thick.
We call it 'marine snow', and that's exactly what it looks like.
Snowflakes.
But unlike snowflakes,
they never melt and over millions of years the sea beds rise...
The ocean levels fall and the ocean floor becomes a salty desert.
The desert that blows all the way to the Amazon...
That was once a sea bed.
And the dust that makes the rainforest grow?
Diatom shells.
It just goes to show how incredibly interlinked everything is.
There is absolutely nothing on one side of the planet that isn't connected in
some way with the other side of the planet.
It's astounding how all the systems down there must work together in order
for us to breathe.
Which is great...
But you only have to mess with oxygen a little bit
for things to start going really wrong.
Ee, two, one.
Lift off, lift off.
Though I've flow 100,000 miles, I'm feeling very still. ?
? Planet Earth is blue and there's nothing left to do. ??
I love the fact that the Earth has a blue sky.
You can look up and all of the various shades of it, you know,
the deepness of it and the way the colors change
close to the horizon and that's everything that we breathe,
and keeps us alive.
And you sort of fool yourself into thinking, it's really, really deep.
Like it goes on sort of forever.
But when you're on board a spaceship and you look straight down,
you hardly see the atmosphere at all.
It's only when you look to the horizon that you can see just how thin our
atmosphere truly is.
The thinnest of delicate blue lines.
It's because the gravity of the Earth is pulling every single one of those air
molecules and pressing it against the ground.
But the further up you go, the thinner it gets.
It's sort of like if you pluck a string on a guitar...
When does the note stop?
And our atmosphere is like that guitar string.
It just gets less and less the higher you go.
But what's surprising is, how fast that happens.
That blue line is so thin that you can walk to where the oxygen starts to run out.
? ?
Being a doctor in La Rinconada means that you have 25,000 patients,
living year-round in a town as high as Everest base-camp.
When Spanish settlers first arrived here, the lack of oxygen killed many
of their babies at birth.
Yet, people still live here.
They still work here.
Because in these mountains, there's something that's lured people through history.
The promise of gold.
This is the limit though.
Humans can't live any higher.
Without enough oxygen, our organs can start shutting down...
And it can happen surprisingly quickly.
So astronauts actually train to recognize their own symptoms of a lack of oxygen.
Of hypoxia.
In my case, there's a slight dizziness.
My vision starts to get a little bit narrow.
The colors become a little more brittle,
like maybe a certain type of painter's way
of using only the primary colors.
Sound changes a little for me.
It becomes a little bit more staccato, sort of a snappy sound to everything
that's going on around me.
And as soon as I put all those things together,
I realize I'm running out of oxygen.
Houston, I'm having a serious problem here.
Serious problem.
Blinded in both eyes.
"What did he just say?"
Can't see, purge your oxygen.
My precious oxygen.
I wasn't really sure how that was gonna turn out, but as the oxygen hissed through and
out my purge valve, the tears that were coming out of my tear ducts
slowly started evaporating.
My vision began to return, bit by bit, and what had caused it was pretty simple.
It was the anti-fog on my visor had been picked up by floating water in my suit and
gotten into my eye.
With confidence, I could reach up and close the valve and stop venting my
precious oxygen out to the rest of the universe.
It's vital that we get enough oxygen; but too much can be just as dangerous.
You see it when you blow on a little tiny fire.
Just blowing that little bit of oxygen turns that tiny spark into a flame.
And it's exactly the same for the whole planet.
A rise in oxygen levels can threaten life on Earth.
300 million years ago, there was a lot more oxygen in the atmosphere.
So much that the planet just burned.
But don't think that danger's all in the past.
Too much oxygen and we fry.
Too little and we choke.
We're walking a tightrope with death on either side,
and just like a tightrope walker
the only thing that can save us is balance.
Balance is crucial...
For the makeup of the atmosphere, and for life itself.
The thing is, we don't fully understand how the Earth manages it.
Despite diatoms having to wait for glaciers and South American trees having
to wait for African dust,
and despite the fact that human population has been steadily increasing,
the relative amount of oxygen in the atmosphere has been surprisingly constant.
For millions of years, oxygen has made up 20.95% of our atmosphere.
Exactly 20.95%.
Everything's somehow buffering out and keeping things pretty darn stable.
? ?
100,000 Buddhists gather here for the festival of Magha Puja.
Each one lights a candle.
They celebrate with their flames at a temple made from a million Buddha's.
? ?
Every breath we take, 16 breaths a minute,
23,000 breaths a day,
every inhale, every exhale of that precious oxygen
couldn't happen without earth, water, wind and fire.
The whole planet works as one to create that thin blue line.
The mark of a living world we've seen nowhere else in the universe.
I really wish that everyone could see the world the way that I've
had a chance to see it.
You have to wrench yourself away from the wonder and the strangeness of it.
And the beauty of space flight is you come back
with a real sense that this Earth is one place.
One shared place.
We're all crew mates on the same ship.
We're not just rare, we're not just special, we are unique and that's what
makes this One Strange Rock.
Next time on One Strange Rock...
Our paradise planet came from collisions, carnage and chaos.
And the impact is still shaping us.
Captioned by Cotter Captioning Services.