Original subtitles

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WILL SMITH: The sun...

Gives us warmth and light.

It is the fuel of life.

Without the energy of the sun almost nothing grows, thrives or lives.

But the sun was not put there for our benefit.

It is not this big jolly ball of nice smiling down on us, wishing us all a good day.

It is not our friend.

The sun is a monster.

A planet killer.

And we don't see that side of the sun down here.

But eight astronauts, with over 1,000 days in space between them,

Can show us how being up there helped them understand the suns bright fury.

JEFF: It's got an incredible amount of power which you

really appreciate when you go out in space.

MAE: Just like the gods of old, the sun can give life and it

can destroy life.

JERRY: It's a mean son of a gun.

It's exploding and it's sending cosmic radiation at us.

-Given the amount of radiation from the sun, there shouldn't

be life on the surface of the earth.

We shouldn't be here.

WILL SMITH: But we are here.

And we owe our lives to this world.

I'm gonna tell you how the earths core...

The air above us....

and life itself work to protect us.

The earth shields us in a suit of armor.

And the way she does it...

Is one hell of a strange story.

(car horn)

♪ ♪

You see that guy in the crowd?

He's just a bit different from the rest of us.

He's a spaceman.

Once he risked his life to fix a telescope 350 miles above the earth.

And he's spent a lifetime studying the stars.

-People still feel this incredible fascination with,

with looking at the sun.

Twice a year it just crosses the line of the cross streets of Manhattan...

And sets at just that right point that it just makes a

beautiful orange glow which permeates the city.

In some sense I suppose I could say I saw more of the

true character of the sun...

Than people who are always on the surface of the earth.

You open the airlock and then turn around and look up.

It's like that great scene in the Wizard of Oz where Dorothy

comes out of the house and it's not black and white anymore.

All of a sudden, the whole world is in color.

WOMAN (over radio): But don't forget those visors.

They do come in handy when that big fire ball is staring at you.

-Yep.

One of my great eureka moments was realizing for the first time when I

was in space that I was seeing the sun in a black sky.

Think of that.

You really see the sun as a star.

Particularly when I was out in the space suit,

the power of the sun just hits you in the guts.

It just goes through your entire body.

LELAND: The temperature extremes are 250 degrees in

the sun and then minus 250 in the shade.

That's pretty incredible and that our suits can withstand those temperatures.

-But even we astronauts only experience a fraction of the sun's power.

It has many weapons it can send our way.

Heat, light and deadly flares that can devastate entire planets.

Look at Mars.

Billions of years ago we think it was just like us...

A potential cradle for life.

But radiation from the sun ravaged it.

Solar flares with the destructive power of billions

of Hiroshima atomic bombs helped chew away Mars's atmosphere

and the oceans evaporated into space.

WILL SMITH: Earth is even closer to the sun than Mars,

so how come we're not dust and ashes?

See, the thing is, our planet is strong on defense.

And every player has a role.

From the edge of space...

To the deepest oceans...

To one of the most hostile places on earth.

SIMS: We'll be sleeping with gas masks on.

Sometimes it'll clear up and be beautiful but most of the

time we'll be wearing our gas masks even to bed.

WILL SMITH: Ken Sims doesn't do nine to five.

This is his idea of a good day at the office.

For over 20 years he's ventured into active volcanoes

across the globe to collect samples of molten lava.

Studying this stuff is one of the best ways to understand

what's happening in the center of the earth and the process

that protects us from the sun.

KANE: Pretty much that whole bottom terrace now is completely covered in brand new

lava flow, isn't it?

-Yeah. And with the new lava flow coming around against the wall there,

we'll have to watch out.

The lava's intensely hot, roughly 2,000 degrees.

It will burn pretty much anything on contact.

-Okay, heading over.

I'll go over just towards the edge here.

We'll have a look.

Whoa.

Holy...

It's just opened up on that side, hasn't it?

-Yeah, totally. -Whoa.

Yeah, Ken, I'm pretty certain that there is absolutely no way we are going down there.

That is without doubt mission impossible.

-Okay, well, we're cancelling this mission.

-Yeah.

-Just anybody with half a brain wouldn't go down there.

WILL SMITH: The new vent means Ken can't take samples from the lake,

but he doesn't need to.

The vent is firing fresh lava right at him.

-There's a lot of lava bombs around here.

It's just covered with bombs.

Wow, I'm...

can see the vent from here.

It's really rocking and rolling.

-I'm gonna head back up, over. -Sure, I'll come back.

The solid lava samples we've collected are radioactive.

They have uranium and thorium in them.

Those elements are really important for maintaining the heat of the earth.

WILL SMITH: But wait a second.

What does any of this have to do with keeping us safe from the sun?

Radioactive lava up here proves there's a raging

nuclear furnace at the heart of our planet.

It is one big ball of incredible heat.

I mean, a very big ball.

But that's not all.

These molten insides are full of iron and nickel.

Rising, falling, spinning in a constantly melting furnace.

And all that churning metal creates its own magnetic field.

♪ ♪

This magnetic field stretches as far as 400,000 miles into space...

surrounding the entire planet.

It is a massive force field and it helps deflect the

deadly radiation that destroyed Mars.

♪ ♪

-For the most part our magnetic field is invisible.

But when the sun flares up, we get to see it in action.

We call it the aurora.

It's pretty much on everyone's bucket list but in space you see it in an

entirely different way.

LELAND: I saw this green glow.

It's almost like a person dancing.

It was a shape and these forms that were moving as we went over.

CHRIS: And the greens and reds and all of the faint colors,

like this enormous ghost of a curtain.

NICOLE: You're not just seeing it with your eyes.

It, you're feeling it.

You're feeling it with your heart as well.

It's a part of you.

-When we look down at the aurora it's all the more

beautiful because we know that we're looking at our planet

keeping us safe from the sun.

WILL SMITH: But you know what?

It takes more than that one shield to keep us alive...

because the sun has another weapon.

A silent assassin.

The assassin's name?

Light.

WILL SMITH: Everything revolves around the sun.

Literally.

It's the big boss of the solar system but its most deceptive

weapon is something we usually think of as our friend.

Light.

It's a hazard astronauts need special protection from.

JEFF: We see the visible light from the sun but there's

also ultraviolet light.

That can actually do significant damage.

JERRY: Every porthole window has special layers, different UV filters.

On space station MIR there was one that was not.

But when I floated over that thing, if you sat there and

had those rays of sun hit you, in less than a minute,

you'd see your skin reddened.

-The power of UV light in space means that without our

gold visors our eyesight could be damaged permanently.

For almost all life on earth facing the sun as we do in space would

ultimately be fatal.

♪ ♪

It's crazy, right?

In space you need a $12 million spacesuit to protect you from the sun...

whereas on the surface of the earth just some lotion does the job perfectly fine.

♪ ♪

We're quite fortunate.

Only about 2% of the really damaging ultraviolet radiation

from the sun actually gets down to the surface.

If every bit got down to earth...

skin would burn in a matter of seconds.

That's just the start.

UV radiation breaks down DNA and turns healthy cells cancerous.

If we were hit by the full force of the sun,

plants would be sterilized...

microscopic life would be sterilized...

life couldn't be sustained on the surface of the earth.

WILL SMITH: Ultraviolet light is vicious so how come we're

not burned to a crisp?

The answer is high above us.

The sun slings deadly UV light at us...

but most of it is stopped in its tracks by a thin blanket

of molecules that we call the ozone layer.

The ozone layer is our second shield in the sky but it's fragile,

extremely fragile.

30 years ago, we discovered manmade chemicals had punched

a hole in the ozone layer.

Is that hole here to stay?

Waiting around to kill us?

Today we're trying hard to find out.

♪ ♪

♪ ♪

Morgan Sandercock is about to test an experimental plane perfect for sampling ozone.

MAN (over radio): Go ahead, go, pressurizing.

We think we can go as high as 90,000 feet. Jim, you're ready to go.

JIM (over radio): I'm ready.

MORGAN: That's the big boy territory.

That's where things can wrong very, very quickly.

If we lose cabin pressure, then the pilots could very

easily pass out and we don't have any automatic systems to

recover from that.

WOMAN (over radio): Getting ready to roll.

WILL SMITH: Now a glider might sound like a dangerous choice so high up,

but gliders don't have engines which means they can't pollute

the team's samples.

MAN (over radio): Got a firm count, dolly off.

WOMAN (over radio): Count, dolly is off, wing wheel is off.

MAN (over radio): Okay, rolling at 11:32.

-11:32, written down, if you can get us the time.

MAN (over radio): Airborne.

♪ ♪

WILL SMITH: The Perlan glider uses air rising over the southern Andes

to reach extraordinary heights.

-Air speed, 70 knots. Looking beautiful, (inaudible).

MAN (over radio): Traffic, yeah.

WILL SMITH: 52,000 feet up makes this the highest glider

flight ever but you've gotta get this high to get a great picture of the ozone layer.

The good news is that thanks to a global ban on ozone

harming chemicals, it looks like the hole is healing up.

Our shield is regenerating.

MIKE: Our planet is not an inanimate object.

It's a living thing and it can heal itself.

JERRY: When we discovered the hole in the ozone layer,

mankind did come together on that one and we banned those substances.

-You look down and you see this fragile planet which supports life

on its surface in the face of the incredible

hostility and so you become much more sensitive,

I think, to the need to protect it.

WILL SMITH: Any way you look at it, the ozone layer is pretty special.

This shield has looked after us for millions of years,

even before mankind came down from the trees, even before the

dinosaurs walked the earth.

Without the ozone layer there would be no human race.

Life on earth would be trapped under water.

WILL SMITH: In Earth's battle with the sun, the sun has

often had the upper hand.

Today the ozone layer protects us from UV but once upon a time,

it wasn't there.

The only safe place for life was under the waves.

Life would probably still be down there if it wasn't for something

new that emerged nearly three billion years ago and found a way

to use sunlight to its advantage.

♪ ♪

JEFF: Billions of years ago as ancient organisms first harnessed the energy of the sun,

they began producing a waste product.

Oxygen.

At first it was just a few individuals, but thousands became millions.

Millions became trillions.

All bubbling up oxygen.

When oxygen gas rises high into the atmosphere something

very special happens to it.

It transforms into protective ozone.

Under the shelter of this ozone layer, first microbes

then fungi and plants migrated out of the water.

And this meant even more oxygen was being produced,

further strengthening our shield against the sun's UV light.

And this would help make possible one of our planet's

most defining moments.

♪ ♪

Protected by a thicker ozone layer than ever before,

a whole new world of possibilities opened up for life on earth.

♪ ♪

We think it was about 400 million years ago when simple

vertebrates first took their tentative steps onto dry land.

It's probable that these early animals were moving around using something that

was still pretty much like the fins that they used to get

around in the water.

With that one small step from water to dry land...

life on earth changed forever.

That was one small step for animal kind and one giant leap for life on earth.

♪ ♪

WILL SMITH: Life spilled out of the water in a billion different ways

taking on a host of forms.

All because of that special layer of oxygen up in the sky.

Right, so that's two shields that our planet gives us.

But the sun has a final weapon.

Heat.

It's pumping out millions of degrees of powerful burn and that

powerful burn is intensified by an ally down here on earth,

one feared by people everywhere.

(chanting in native language)

(chanting in native language)

(chanting in native language)

(chanting in native language)

(chanting in native language)

WILL SMITH: Volcanoes make terrible neighbors but even if you live

far away from one,

like on the other side of the planet,

a volcano could still make you feel the heat.

Much of this gas cloud is CO2, carbon dioxide,

and CO2 is a killer.

It traps heat in the atmosphere.

If you wanna know how dangerous CO2 can be,

just try taking a walk on Venus.

-The surface of Venus is hotter than hell.

CHRIS: Surprisingly the planet with the hottest temperature

at the surface in our whole solar system is Venus,

even though it's not the planet closest to the sun.

That is purely the effect of having too much carbon dioxide

in your atmosphere.

WILL SMITH: On earth volcanoes have been firing CO2 into the sky

for billions of years.

So, here's the question.

How come it's pretty cool here on Earth while Venus is fully baked?

Well, the earth has its own way of dealing with CO2, unique to this planet.

But it can easily go wrong.

WILL SMITH: The sun threatens us with solar explosions and ultraviolet light

but its most dangerous weapon could be plain old heat.

It can cook planets, especially ones wrapped in a

warm blanket of carbon dioxide gas.

But the Earth has its own very elegant way to stop itself from being

boiled dry by the sun.

The best way to see it in action is from 250 miles straight up.

JEFF: Just like the human body has ways of keeping all of our systems in check,

similarly the earth has its own regulatory system...

and it's kept just about the right amount of carbon dioxide

in the atmosphere.

From space you got a unique perspective.

The process starts with something no other planet in

the solar system has.

An air conditioning system made possible by rain.

Normally we think of the rain as being pure water coming

down out of the sky but actually it's carrying

dissolved carbon dioxide from the atmosphere and

this makes it acidic enough to dissolve rocks.

Ultimately this water, silt and locked-up carbon dioxide

will all get washed into the planet's rivers.

This process goes on right under our noses every day but

sometimes it can make itself visible in a truly spectacular fashion.

WILL SMITH: These people get to take a small peek at the way our world keeps

itself cool and, wow, is it impressive.

♪ ♪

WILL SMITH: Hidden in all that water is carbon

pulled from the sky.

This great river is forcing it into the ocean.

Seen from above its raging majesty is laid out for the stars to see.

-Looking at rivers from space you really get a sense of the movement of huge

amounts of material.

It's unforgettable.

You can see the brown color which goes way,

way out into the ocean.

As rivers spit out huge quantities of sediment and

locked-up CO2, carbon that was once in our atmosphere gets buried at the bottom

of the ocean and that helps cool down our planet.

Over millions of years the cycle of rain, rivers and

volcanoes has helped balance the CO2 in our atmosphere,

keeping us warm in the coldness of space while

preventing us from being boiled alive by the sun.

I had studied earth science but when you actually go into

space you feel it on a visceral level.

You realize it's the living Earth.

LELAND: All of these systems on the planet whether it's,

you know, volcanoes, whether it's currents in the ocean...

are shaping and molding this planet that we see.

NICOLE: It looks like it's its own organism.

Like it's living, it's breathing, it's the...

as the clouds move, I mean, it's almost like it's...

it looks alive.

WILL SMITH: Nature's ancient systems have kept our planet safe for billions of years

but now they're changing in a very big way.

-Right now humans are pumping 60 times more CO2 into our atmosphere

than volcanoes and there isn't enough time for the Earth's

air conditioning system to correct the problem.

The planet is getting hotter.

How much hotter?

That depends on us.

It's not gonna be easy but my hope is that just as we fixed the ozone hole,

humans are ultimately gonna be able to fix this.

WILL SMITH: Human beings don't have to just stand by and watch Earth's war

with the sun.

We can help. We have to.

For almost four billion years our planet has held off the power of the sun,

but that fire ball will get us in the end and thanks to

Jeff Hoffman we've been given a terrifying glimpse into the future.

A very bright future.

WILL SMITH: For almost four billion years our planet has

shielded us from the sun.

But those shields won't protect us forever.

Ask Jeff Hoffman.

He was part of the team who allowed us to see our ultimate

fate when he helped fix the Hubble telescope.

JEFF: Hubble couldn't see straight.

It was the butt of jokes of late night comedians.

It was denounced in the halls of the US Congress as a techno turkey.

It was a disaster.

So fixing Hubble was critical for the future space

activities that NASA wanted to carry out.

We are inspired. We are ready. Let's go fix this thing.

Both as an astronomer and an astronaut to take my two hands and put them on

the Hubble space telescope and actually fix it...

WOMAN (over radio): Endeavored motion of the aperture door.

-Roger, we're alive.

That's been a great source of satisfaction.

We have a good release.

WOMAN (over radio): Copy. And we very much appreciate it.

MAN (over radio): I do have some good news for you, Jeff.

The payload folks have gone through a complete checkout and are fully functional.

-Great news.

WILL SMITH: Thanks to Jeff and the team, Hubble went from

turkey to triumph.

-Some of these images are almost biblical in their intensity.

They still give me goosebumps when I look at them.

So many different forms and colors, it looks like the work of some psychedelic artist

but it's the universe that we live in.

I mean, it's extraordinary.

WILL SMITH: The work on Hubble meant we could capture the exact moment

when a star like the sun dies.

♪ ♪

-Around five billion years from now, the sun is going to grow in size,

swallowing up the earth.

And in those final moments, all matter on our planet,

all traces of life...

will be torn apart as the Earth is enveloped by the sun.

When I came back on Earth and looked up at the sun,

it looked the way it had always looked before except I knew

that I had seen it like it really was.

It's like seeing somebody's true nature very briefly when

they let their guard down and then you never see that again.

CHRIS: Earth's protected us from the sun for billions of years.

It's been one of the main reasons that life has been

able to thrive here on the surface.

JERRY: As a biological creature we need the Earth to protect us

and these shields provide sort of a blanket over us to just keep us secure

and sort of carefree on the planet.

-Were we just lucky that all these things happened to be in place?

Well, of course if they weren't in place, we wouldn't

be here and I wouldn't be talking about this.

WILL SMITH: Next time you take a walk outside when the

sun is high in the sky...

take a moment and think about the iron churning at the

Earth's core, the oxygen bubbling out from under the sea,

the rain crashing onto the rocks, all these things

that came before us and made this world possible, those

chance events, those planetary systems that allow our little

moat dust survivve in a sunbeam.

You, me and everyone we know, we're lucky, lucky to get as

far as we have and lucky to be here now.

But this is not the end of the story.

What's up? How are you doing?

Next time how all life on Earth got started.

And let me tell you, that takes strange to a whole new level.

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Captioned by Cotter Captioning Services.