One Strange Rock

We sure lucked out with Planet Earth.

Blue skies, rolling hills, water everywhere.

I mean, this place is nice.

But our home didn't come like this out of the box.

Earth was a real fixer-upper,

and it took some seriously hard work to build this paradise.

Nearly four billion years of renovation.

Some tiny, some huge...

to make this house a home.

And when you get up off the planet,

you realize life is the one holding the hammer.

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.

Creatures on Earth don't just live and die.

They actually change the world around them.

The diversity of life can be seen everywhere,

from the coral reefs to the mountaintops.

The colors of life shine out.

You can just feel the life that is there

as you observe it from above.

When you look at the planet,

you realize that it's life that formed it that way.

Land, sky, rivers, rock,

all were shaped by life.

But life doesn't just create.

It also has the power to destroy.

So this story isn't just strange,

it's scary.

New York City.

Home to almost nine million people...

and this guy.

Astronaut Mike Massimino.

Right across the 59th Street Bridge, where's that?

Queens.

Yeah, yeah, but what's the name?

What part of Queens is that?

Long Island City.

That's what I was thinking of.

Yeah, Long Island City's right across the street there.

Where did you live originally?

Originally, I came from New York,

and then I lived in Houston, Texas, for 22 years.

I was six years old when Apollo 11 landing upon the moon.

Eagle, we got you now, it's looking good. Over.

You are go to continue powered descent.

Okay, engines stopped.

We copy you down, Eagle.

The Eagle has landed.

Probably by the time I was 8 or 9,

I realized that I was no fearless test pilot

like Neil Armstrong.

I was kind of a scared kid.

I didn't like heights, I still don't like heights.

I didn't like going fast.

So I thought maybe this wasn't the best job for me.

But New Yorkers don't give up so easily.

After years of grueling training,

Mike made it into space.

And up there, his fears melted away.

- Okay. Looking good. - I'm coming out.

Mike, you're doing good.

My second spacewalk, things were going well,

and I had a couple moments.

I took a look at the planet and...

This is incredible.

I started to become a bit emotional.

And just the sheer beauty of it,

I started to cry, and I could feel the tears welling up,

and what I thought was, 'This must be the view from heaven.'

If you could be in heaven, you look down on a planet,

this is how we must look from heaven.

And then I thought to myself, 'No. That's not right.

It's more beautiful than that.

This is what heaven must look like.'

And I felt like I was looking into a paradise.

Earth is a kind of Eden,

but if Mike had been orbiting way back in the day,

he wouldn't be looking down at heaven.

He'd be gazing straight into hell.

All that fire and brimstone had a role to play.

The inside of our planet is melted rock,

churning and turning.

That means that everything on the surface shifts and slides.

Earth's fiery heart powers some big changes.

And that's great news

for dinosaur expert Omar Medina Ramírez.

No need to dig down into the dirt;

just stand back and take in the view.

The power of the planet can take a lakeshore

and flip it into a cliff face.

But these rock formations and the entire continent they're on

might not even be here

without a particularly weird form of life.

Part algae, part fungi,

it grows in the harshest places,

and is a food source

for Dasher and Dancer and Prancer and Vixen.

Hoo-hoo! Ay! Ay!

Gsh! Ay! Ay! Ho!

Lichen are a pretty cool form of life.

They exist just about everywhere on the surface of the Earth.

About 8% of our planet is covered by this stuff,

and they can change the formations, the rock formations,

just by their existence.

As lichen grow, their fungal filaments

physically break apart rock.

But strange as it sounds,

this process will eventually help create new land.

Over thousands of years,

lichen and other terrestrial life-forms break down rock.

This creates huge amounts of microscopic particles.

As some of these particles get washed out into the oceans,

they trap water.

Over time, this locked-up water is pulled deep inside the Earth,

where it helps mantle rock melt and flow more easily.

Ultimately, this leads to more volcanic eruptions

back at the surface.

But the amazing thing is that all this lava

means new land is formed that wouldn't be there otherwise.

Life helps create the land.

Best guess is, without life,

Earth wouldn't have seven continents.

There would only be enough land for about one

floating in the middle of a seriously big ocean.

Life helped make the ground we walk on.

But it didn't do it overnight.

When you're in space,

you get a different appreciation of time,

compared to what we have on the Earth.

And what you see are changes in the Earth

that took place over sometimes millions of years

or, or even longer.

I think life, no matter what form it is,

whether it's a simple form like lichen or an animal

or a more complicated form of life like us,

whatever level that life-form takes,

it is going to change its planet.

It might just take a while to do it.

From the perspective of a space station,

suddenly you can see the entirety of the world's history.

It changes your fundamental feel of time.

Your fundamental perception of the age of the world,

and even though I knew the world was 4.5 billion years old,

I'd never got a sense for what that meant.

It took billions of years for life to mold a barren rock

into the world we know.

But things didn't just get better and better;

sometimes they went wrong.

Like, almost end-of-the-world wrong.

I'm a sucker for a tropical island.

I mean, I get off the plane and head straight for the beach.

Cool sea breeze and sand between my toes.

But get this:

all of that sand down there?

Most of it came out of the wrong end of a fish.

We'll head out towards the coral reef.

We'll drop down to about five meters,

and we'll survey along there, I think.

You can find parrotfish on reefs throughout the tropics.

You see them active on the reef,

feeding on the hard coral material continuously.

And the amazing thing is that you can hear

this incredible grinding, crunching noise.

That really gives you a sense of the life on the reef.

After the parrotfish have eaten the coral,

they then excrete it as sand.

In one year,

one fish eats enough coral

to poop out a ton of sand...

Literally.

And there's an awful lot of fish here.

That same sand material

that you find in the parrotfish poo

can be found in the islands themselves.

On some islands,

the sand material is made up of over 70% parrotfish poo.

The parrotfish are absolutely crucial

to the development of these islands.

But life's not done.

Fish form the fresh beach,

then more life follows on.

And presto,

instant island paradise.

As you fly across,

there are little light blue rings

down in the water beneath you.

There's the deep blue of the ocean around them,

and then all the different changing blues that are possible

as the water gets shallower and shallower.

But what's intriguing to think is that living organisms

down there created that beautiful vista

that is visible from space itself.

It's kind of amazing what a small creature can do.

That a bunch of little fish can build an island

just by going about their daily routine.

That's quite an impact.

Parrotfish aren't in the business

of seaside resort development.

I mean, they were just snacking.