One Strange Rock

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,