Original subtitles

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.

These islands were a happy accident.

But life's little accidents don't always work out so well.

About three billion years ago,

bacteria in the oceans of the early Earth

produced a by-product... oxygen...

Which transformed our world.

But when this accidental waste gas filled the atmosphere,

it reduced levels of warming methane,

cooling the planet.

Earth started to freeze,

from the poles all the way down to the equator.

It froze like a giant snowball.

Billions of years ago,

things weren't looking that great for us,

but thanks to all the planet's water,

we got a lucky break.

Ice floats on water,

and underneath it is a kind of sanctuary.

Life managed to cling on down there, under the ice,

for millions of years

until eventually the planet's volcanoes saved the day.

We think that as they pumped out carbon dioxide,

the planet began to warm up.

The ice melted, and life on Earth really took off.

Life almost killed itself

when it messed with the atmosphere.

But it survived...

and put its roots down on land.

The creatures that emerged,

weird and wonderful and new,

helped build our modern world.

But not in the way you might expect.

They don't walk, they can't see,

they barely even move,

but plants are almost unstoppable.

Give them enough time,

and they are Earth's ultimate transformers.

Roots rip through rock like slow-motion excavators.

But they don't just destroy.

Those plants?

They shape how rivers run.

Plants have had a big impact on the Earth.

As plants grow, their roots spread out and intertwine.

They help hold soil together, like a kind of living glue.

Plant roots make riverbanks more solid,

so instead of spreading outwards,

plants cause rivers to get deeper,

and then begin to wind and switch back on themselves.

Rivers and land formations stand out.

It's almost like somebody has painted trees on the planet.

These bendy rivers have become a crucial habitat

for all kinds of living things,

including us.

You look down at Earth

and you see the Nile River.

You know, the cradle of civilization,

the Tigris-Euphrates.

The Yangtze over in China.

And you just sort of have an appreciation of history

and of mankind becoming civilized.

We've founded some of our greatest cities

at a bend in the river.

And plants help bend those rivers.

Once we settled, we started to build.

Brick by brick and rock by rock.

Life gave us perfect plots of building land,

but it gave us even more than that.

All those rocks we built with?

Some of them used to be alive.

Be super careful with the rock here.

It's really not so great.

Yeah.

I'm watching you.

Oh, my God.

Good job.

I'm specially aware of the landscape

from a geological point of view.

Can you find any gear?

Got a good hold at least.

Because obviously, my first focus is the rock.

This rock wasn't made from molten lava.

It's made of shells and bones.

Layers and layers of life that died and sank

and were squeezed into stone.

Limestone.

Limestone isn't the most solid rock.

Be careful.

There is always the possibility

of rock falling above you.

But I think I can keep on climbing across the chimney,

which makes it a bit easier.

Alright.

When you've got this tiny little summit

where nobody's been on top of it,

there is obviously something very special.

Woo-hoo!

Woo-hoo!

- Good job! Good job! - We did it!

Limestone is soft because it's made of shells.

That makes it tough to climb,

but easy to cut and carve and make into monuments.

In places, you can still see those seashells

in the monuments' walls.

- Can I help you? - How you doing?

Fine. You want a ticket?

Next train to Bronxville.

To Bronxville. Okay, Bronxville.

Grand Central Station,

you can look in the beautiful limestone

that cathedral-like terminal is made out of.

You can see evidence of little fossils

right in the rock.

Next time you're catching a train at Grand Central Station,

take a look at the rock,

and you'll see some evidence of the animals

that once were here on Earth many years ago.

It's not just building material.

Almost everything we think of as being man-made

has been given a helping hand by other life-forms.

The tar in the road.

The fiber in your clothes.

The polish in your toothpaste.

All these things are made from organisms

that died millions of years ago.

If it wasn't for those prehistoric critters,

we'd struggle to turn on a light,

let alone build a space station.

We've thrived with a little help from our friends.

But it's not all smooth sailing.

Because success brings its own problems.

Life has been shaping the Earth for billions of years.

Now, it's our turn.

We may be new here,

but the changes we're making are pretty easy to spot.

Flying over the Earth during the daytime,

you can't see buildings or motion or people at all.

It almost looks still and silent,

almost like a painting that you're looking at.

When you pass into nighttime,

then wow, you know, the planet comes alive.

Space becomes a very magical place at night.

You can see where people are living,

you can see where civilization exists,

because you see their lights.

If you see one of these cities,

space gives you a different perspective on it.

At nighttime, the pattern of lights,

you just think 'humanity' when you see that.

It's so obviously man-made,

because you'll see these straight lines of lights,

or you know, circles of lights,

where cities are just built in rings.

Seeing the planet at night from space

lets you see the footprint of human beings.

The city lights at night, the byways, the highways, the homes,

you see all of that.

Makes you wonder how powerful the human presence is.

We have spread far and wide over this old rock,

adding a whole new layer to the planet's surface.

But we didn't make all of this stuff out of nothing.

Franco Barattini helps extract

some of the most beautiful natural resources on the planet,

but it's a dangerous job.

Marble has been mined here since Roman times.

It's done with skill and loving care.

But you know what?

A showroom isn't the only place

to see that gleaming white stone.

Bright white marble in Italy, you can see that.

It's looks like there's a snowfield in a time of year

when we wouldn't have any snow.

But it looks as if it's snow,

because it's that white marble being taken from the Earth.

And it's not just marble.

When you're floating above the Earth,

you see many different examples

of how our desire for natural resources

is changing the planet,

and not always in a good way.

There are places on the planet,

when you fly over top of it,

you see these vast stretches of land

that have been mined for coal or mined for minerals or riches,

and this leaves a blight on the surface of the planet.

And it's ghastly at times to see some of this.

The scars and scratches in the Earth's surface

are one thing,

but the damage we can't see is the real danger.

Of all the changes that we're making to the Earth,

I think it's changes to the atmosphere

that we should be the most worried about.

That's the one that could really lead to some serious problems.

You just have to look at what happened in the planet's past

to see how badly it could go.

Our planet has always been changing.

It's been changing over billions of years.

We're just the latest form of life to do it here.

There's a big difference between then and now,

and we're making these changes,

but we're aware of what's going on,

and we have brains in our heads that can allow us

to try to understand what's happening and control it.

We're transforming our planet every day.

But it's very possible we could hurt it so badly...

that we can no longer live here.

And what if we do?

What would happen if humans disappeared?

Life has created the most remarkable planet

in the solar system.

But there is no guarantee

that humans are gonna always be here to appreciate it.

Thing is, the Earth will go on spinning,

life will go on living.

Astronauts like Mike can see that as clear as day.

There was this one particular time

when I was on the space shuttle,

and we were going from darkness into light.

And I could feel the warmth of the sun coming.

As I looked down at the Earth,

there was this line that was moving,

and the thought that went through my mind was,

'The sun will come up tomorrow.'

This cosmic dance of our planet going around the sun

and rotating as it does this,

this has been going on for billions of years.

It'll be going on for a long time after we are gone.

The Earth doesn't need us.

Neither does life.

And if humans don't make it,

life will go on changing things.

Even the things we leave behind.

Minoru Kinoshita left here when he was 13 years old.

This is the first time he's been back in 50 years.

Hashima Island was once

the most densely populated place on Earth.

People came here to mine coal.

When that ran out, everybody left.

This place was abandoned practically overnight.

40 years later, life has started taking Hashima back.

If humans died out,

most of our man-made world would fall apart.

Life would rip it up and transform it.

Reclaim and remold it.

Our buildings would crumble,

our towers would fall,

our lights would go out.

But the Earth would endure.

Not so different from the way we found it.

A big, blue ball...

that life made into a home.

How you doing?

One hot dog with mustard, please.

I think my concept of what I consider to be home

changed over the years.

Alright. Thanks very much. See ya.

When I was a little person,

my home was my home on Long Island and Franklin Square,

and my block surrounding it.

You know, that was my world, I guess.

Going to space and seeing where we live from above

and then turning and looking to the rest of the universe...

I think now I consider my home to be Earth,

and that is my home.

I might live in one part of it,

but I think of my home now as Planet Earth.

That's our home.

We moved into a populated planet,

and in the short time we've been here, we have changed it.

But we're not the master craftsmen.

We've just been moving furniture around.

Life worked on this planet for billions of years

before we even walked in the door.

It transformed a barren rock into a paradise.

A paradise we should be careful to hold on to.

Life transformed this planet,

but we aren't the only rock out there.

Next time...

Do we have any neighbors?