The Planets and Beyond

Our galaxy, far in the future.

A planet shrouded in turbulent, dense clouds.

Buried deep below,

an alien landscape...

Extreme pressures, and a scorched surface

with sky-high temperatures.

But this isn't a distant extraterrestrial world.

It's earth's future, maybe a billion years from now.

We know this because earth has a twin...

Venus.

And Venus has already descended into hell.

Have you ever dreamed about travelling out of this world?

My name is Mike Massimino,

and I turned that fantasy into a reality

when I space-walked to repair the Hubble space telescope.

Great job, Mike.

Now, as we expand our knowledge of our solar system

from Mercury to the cosmic unknowns,

I want to take you on a personal journey to...

"The planets."

Welcome to "the planets."

I'm Mike Massimino.

I got to live out my childhood dream

when I first travelled to space

in 2002.

Looking down at the earth from the Hubble space telescope,

I was blown away by this perfect blue sphere

in the middle of space.

As peaceful and inviting as our planet is,

our neighbor, Venus, is the complete opposite...

No water, scorching temperatures,

and crushing pressure.

And just when you think there's nothing in common

between these two planets,

it turns out they're actually siblings.

Take a look around the solar system...

Eight planets orbiting a central star, the sun.

Among them is earth

and its neighbor, Venus.

Earth, our home, is an oasis for life.

Venus is the stuff of nightmares.

Venus and earth couldn't be more different.

The earth is this beautiful planet,

and there's water everywhere.

It's ice at the poles. It's water in the ocean.

It's in the atmosphere as water vapor.

But then you look at Venus.

It is the worst place imaginable.

It is so hot on the surface, crushing pressures.

It couldn't be any less supportive of life.

To me, the planet Venus

is sort of a classic definition of the word "hell."

If you were to transport to Venus

and experience the environment there,

you'd quickly want to return back to earth.

The conditions on Venus

are among the most inhospitable in the solar system.

It's going to be a competition between whether or not

you're gonna be cooked to death or crushed to death.

Earth and Venus may seem like very different worlds,

but they shouldn't be.

They're roughly the same size, same mass,

and made from the same stuff.

And they started out as twins.

Early Venus and early earth were very similar.

They were twins,

probably nearly identical twins, at their earliest stages.

Given that Venus is so earth-like in so many ways,

it's really odd that it is so different than the earth.

And this makes it one of the biggest mysteries

in the solar system.

Somewhere in their two histories,

the earth and Venus took two very different paths.

The result?

Two totally different worlds.

Their paths were so different, you could hardly believe

that one would have been related to the other.

But now, the opposite thing's going to happen.

We're gonna catch up with our twin.

We're gonna evolve to be a lot more like Venus in the future.

In the future,

the two planets' paths will converge,

and they will become twin-like once again.

There is going to be hell on earth.

The oceans will vaporize. The land will melt.

Our hospitable blue planet will vanish,

replaced by a fiery, molten world.

We are actually on the earth at a time

when there's water and rain,

and it was so easy for life to take hold.

But that's gonna change.

And take a look in at Venus and have a look at our future.

How will this happen?

The roots of our home world's destruction

are buried deep in our twin planet's past.

It's very much true that, in studying the past of Venus,

we are also studying the distant future of earth.

Both planets share a violent birth,

scarred by brutal planet formation,

giant cosmic impacts, and rampant volcanism.

We're trying to reconstruct things

that happened in the ancient, ancient past.

It's almost like forensic planetary geology.

4.6 billion years ago, hundreds of infant planets

begin to form around the new sun.

Among them, the baby Venus and earth.

And as they hurtle around the sun,

collisions are inevitable.

Planet formation is like a demolition derby.

In a derby, the cars are racing around a track,

going around in circles at different speeds.

Well, it's the same thing with planets.

The material is orbiting the sun.

It's going around, and they're all going at different speeds,

at different angels, different trajectories.

And sometimes, boom.

In this derby, planet hits planet.

Two become one...

Violently.

You have these large bodies that are hitting each other

at really high velocity.

It's really a very hot, violent mess.

The amount of energy released

in these impacts is huge.

It completely dwarfs

all of the nuclear weapons on earth combined.

And yet, somehow, on these scales,

you wind up forming gigantic objects that we call planets.

Earth and Venus become voracious planet eaters.

But two spectacular collisions set the twins

on very different paths.

That was the moment Venus and earth went through

this divergence to what has now become

these really dramatically different worlds.

The divergence begins

when a Mars-sized object hits earth.

The impact makes our planet spin faster.

The core spins with it, generating

a powerful magnetic field around the planet.

The field fends off the worst of the sun's radiation.

Around the same time,

Venus takes a head-on hit from another infant planet.

This impact explains something very weird about Venus.

Venus is actually rotating

in the wrong direction.

How could that be?

Well, what if it got hit really hard by some object?

That could do it.

An object so huge,

Venus stops in its tracks and begins to spin backwards.

If you think about how much energy

and what size you need to change a planet's spin,

that is an incredibly large hit.

But the backspin is slow...

243 times slower than earth.

Without a fast spin,

Venus' core can't generate a strong magnetic field.

It has no protection from the deadly stream

of particles blasted from the sun.

Venus does not have a strong magnetic field,

and so it has suffered the full brunt

of this wind blasted out from the sun.

The tale of two planets

now splits radically.

Venus will roast

under a violent, suffocating atmosphere.

Earth will give birth to oceans,

life, and intelligence.

But ultimately, these twins' fates

are the same.

Earth's future is Venus...

Pure hell.

4.6 billion years ago,

two nearly-identical planets formed...

Earth and Venus.

Earth blossomed into a colorful haven

for life to thrive,

while Venus is the definition of hell.

How did they turn out so different?

Images from space probes sent to Venus provide the answer.

Venus is a vision of hell.

And one day, we'll meet our twin's fate.

So, how will our blue planet

become a superheated wasteland?

Only Venus can really tell us.

Something happened to Venus long in its past

to make it a completely different planet

with a completely different personality

than the earth as we know it today.

Two, three, four.

We earthlings sent our first probe

to our sister planet in 1967,

and we've been sending them ever since.

What they found blew scientists' minds...

Rocks that look like granite.

What makes that interesting is that, to make granite,

you need water.

That means that there must have been abundant water

for it to have formed in the first place.

Abundant water on scorched Venus?