Original subtitles

Narrator: The history of our solar system

Is the history of us,

But how well do we really understand our cosmic roots?

To understand where we are now,

We need to understand where we were at the beginning.

Narrator: Remarkable new evidence

Threatens to rewrite almost everything we thought we knew

About the birth of our planetary backyard.

Oluseyi: The history of the solar system

Isn't as neat as eight planets formed

And now they're the same eight planets today.

Greene: Anything that challenges the status quo

And our thinking about that is profound.

It profoundly changes our sense of how we got to be.

Narrator: Did one of the largest stars

That ever lived give birth to the sun?

Was our solar system home to two stars, not just one?

And did supersized planets once roam

Where the earth sits today?

There were planets that probably got ejected

From the solar system entirely.

There may have been planets that were actually

Thrown into the sun.

Narrator: This is the all-new birth story of our solar system,

And the race to rewrite history.

-- Captions by vitac -- www.Vitac.Com

Captions paid for by discovery communications

♪

Today, across the world, scientists are grappling

To solve a serious problem.

Their best theories for how our solar system formed

Just don't add up.

Understanding the history of our solar system

Really is the story of our origin.

We happen to be here today on this planet,

Because this planet formed from the raw ingredients

That formed our solar system.

Narrator: For decades, scientists have known

That the sun and the planets

Were born out of the same cloud of gas and dust

That collapsed under gravity 4.5 billion years ago.

But that collapse needed an extra ingredient

To get things started.

Somehow the cloud has to collapse.

Something has to give it a shove,

Make one area denser than another,

And then gravity can take its course

And bring things together, and begin to form

Our sun and the planets.

But it doesn't just happen spontaneously.

There needs to be a trigger.

Narrator: According to the conventional theory,

That trigger was a supernova --

An exploding star.

The supernova sends a shock wave of material

Blasting through space.

It smashes into a nearby cloud of gas and dust,

Forcing it to collapse.

A new star, our sun, sparks into life.

And the remaining swirls of gas and dust

Condense into planets.

Our solar system is born.

♪

The supernova trigger theory has reigned supreme for decades,

But remarkable new evidence now threatens to override it.

At the university of california,

Ed young hunts for cast-iron evidence

To support the supernova trigger theory.

He studies some of the rarest rocks on earth.

Meteorites that are as old as the sun.

Young: I'm pulling out this particular meteorite.

It's a meteorite that fell in australia in 1960.

It's about 4.5 billion years old, very ancient.

This rock is pretty much as old as the age of the solar system.

Narrator: Ed looks for chemicals inside these early rocks.

These chemicals could prove a supernova shock wave

Really did trigger the formation of our solar system.

Young: The solar system formed by the triggering event

Being a supernova, then this rock would contain

Some of the material that was spewed out

By the supernova at the time of the explosion.

Oluseyi: When a supernova explodes,

It sends out radiation in every direction,

And that radiation encounters other stuff,

And the fingerprint of the supernova

Is left on everything it touches.

Narrator: Ed looks for traces of a chemical

That forms in the abundance in supernova shock waves.

It's called iron-60.

Young: We use this instrument to measure

With great precision the various elements

That make up that meteorite.

If we find evidence for iron-60,

Then we have possible evidence for a supernova nearby

At the time the solar system formed,

Because supernovae form the iron-60.

Narrator: The team prepares the sample.

They grind the meteorite,

Setting its primordial grains free

After 4.5 billion years of imprisonment.

Then, they dissolve the grains in acid

And finally, place the sample

Inside a machine to measure its chemical composition.

The machine heats the sample to extreme temperatures,

Smashing it into its component chemicals.

Young: We walked our sample over to this mass spectrometer.

It has a plasma that's as hot as the surface of the sun,

And so it's a very efficient way

Of analyzing ratios of elements that we put in there.

Narrator: After just a few minutes,

The results flash up on ed's screen.

They list the type and abundance

Of every chemical in the meteorite.

But how much of the supernova marker, iron-60, will he find?

Young: The slope of this line indicates

A modest amount of iron-60 in the early solar system.

Less than had previously been estimated.

Narrator: The result is a surprising setback

For the supernova trigger theory.

Young: The fact that this slope is lower

And the amount of iron-60 that implies

Is less than previously thought,

Tends to argue against the notion

That there was a supernova exploding

Right near where the solar system was born

At the time it was forming.

Narrator: Ed's results suggest that a supernova

Can't have triggered the formation of our solar system.

If the violent winds of a supernova

Didn't provide the trigger...

What did?

Young: Now that we know that iron-60 is not a smoking gun,

We have to start rethinking the origins of other isotopes

That were present in the early solar system.

Narrator: Ed goes back to his results.

He searches for unusual levels of other chemical elements.

One stands out --

Aluminum-26.

Young: Unlike iron-60, aluminum-26 can be formed

By other ways -- ways other than a supernova.

Narrator: Aluminum-26 is commonly produced

By oversized stars.

But there's only one monster

With the power to kickstart the birth of a solar system.

A giant wolf-rayet star,

50 times the size of the sun.

The most massive, brightest breed of star in the universe.

Hidden under the surface, it's a cosmic chemical factory,

Fusing atoms of hydrogen together

To produce heavier elements like oxygen and aluminum

But, crucially, not iron-60.

This stellar furnace creates so much heat

It unleashes winds of nearly five million miles per hour,

Which slam into the surrounding clouds of cosmic gas and dust,

Sweeping them away from the star

And piling them up into a dense,

Chemically-rich shell of material,

Trillions of miles wide.

If a supernova didn't explode and collapse the cloud

That made the sun, what could have?

Well, maybe it was a very, very high-mass, luminous star.

There's a type of star like that called a wolf-rayet star,

And they are incredibly violent, blasting out radiation.

Narrator: Wolf-rayet stars are extremely rare.

Of the two billion stars in the milky way,

Astronomers have only spotted 600

Of these spectacular, bloated objects.

Thaller: They are very, very massive stars

That are almost ripping themselves apart with winds.

Winds of high energy charged particles.

Oluseyi: The winds of a wolf-rayet star

Are almost like a slow explosion of the star,

And because that's the case,

You don't get these radioactive iron elements,

So the fingerprint of the wolf-rayet is very different

Than that of the supernova.

Narrator: Did the ferocious winds from a wolf-rayet star

Trigger the creation of our solar system?

The theory ticks a number of boxes,

With one exception.

The clouds of gas that give birth to stars

Are normally very cold,

But wolf-rayet stars and the winds they throw out into space

Are scorching hot.

Far too hot to form a star like the sun.

But could the chemical-rich shell

That surrounds these massive stars hold a clue?

♪

♪

Narrator: At the university of chicago,

Astrophysicist vikram dwakadas,

Part of a team that uses computer simulations

To peer inside giant wolf-rayet stars.

He wants to know if the outer shell of one of these stars

Might have triggered the creation of our solar system.

Dwarkadas: The solar system cannot be formed too close to the star

Because these stars are very hot.

The wolf-rayet star is very small out here.

It's a single point at the center,

And in fact, this single point is still about a few times,

Up to 15 times the size of our sun.

Then this medium out here

Could go up to about 10 billion times the size of our sun.

Narrator: Vikram believes the distant outer shells of wolf-rayet stars

Have all the raw chemicals needed to build a solar system.

And because this dense layer lies trillions of miles away

From the hot central star,

It may have just the right temperature for star birth.

Dwarkadas: What this animation shows, basically,

Is the environment around the wolf-rayet star,

And what you're seeing is basically the density structure.

So, you can see that there's very low density inside

And very high density outside, which we call the dense shell.

Narrator: Vikram is convinced that our solar system

Was born inside the dense outer shell of a wolf-rayet star.

But to prove his theory, he needs to show

These cooler, outer layers can be rich in aluminum-26 --

The chemical found in abundance in early meteorites.

Dwarkadas: The aluminum-26 is produced by the star

At the very center, and what we want to know first

Is whether it can survive its journey

All the way from here out to the dense shell.

Narrator: Vikram suspects the delicate aluminum-26 atoms

Survive by attaching themselves to particles

Blown away from the giant star.

We find that dust forms around the star

During the wolf-rayet phase,

And in our theory, the iron actually hitches a ride

On the backs of these dust rings.

Narrator: Vikram's ideas are very new,

But if he's right, we can piece together

A new birth story for our solar system...

...Around one of the largest stars that ever lived.

The wolf-rayet shell is enormous --

20,000 times the size of our solar system.

Peeling back the outer layers

Reveals a concentrated patch of gas and dust.

A gust of hot stellar wind slams into the patch,

Triggering it to collapse.

It starts to spin, and flattens out into a disc.

The pressure at the center rises so much

It triggers a new dawn.

The gas ignites, and gives birth to the sun.

That's how the hot winds of a giant star

Can breathe life into thousands of others, like our sun.

These findings change everything we thought we knew

About our cosmic birth story.

It's kind of neat to think that it might be one of these

Rare, beautiful, violent stars

That triggered the formation of us.

Thaller: That means that we come from something rather special.

In many ways, creation and destruction

Turn out to be two sides of the same coin.

Narrator: New investigations and new evidence

Are forcing astronomers to reconsider

The birth story of our solar system.

But is that all we've gotten wrong?

Is it possible that our sun was born with a twin?

Astronomers find planets in other solar systems

Revolving around two stars,

Or sometimes more.

Thaller: It is so easy to assume that we are the normal things.

That we are not the exception to the rest of the rules.

When you look up into the night sky,

You see all these stars overhead,

But do you realize that most of those are not a single star?

They're actually two stars that are so close together

You can't actually see them as separate?

Narrator: Of all the stars in the night sky,

Around 80% sit so close to a neighboring star

That they orbit around each other.

These gravitationally bound stars

Are known as binary pairs.

Oluseyi: A binary star system is when two stars

Are locked in orbit around each other,

And that's a very common scenario,

But binaries are incredibly common

And they're very important for understanding

How stars form and evolve.

Narrator: But if binary pairs are so common,

How come we don't see two suns in the sky instead of one?

Astronomers always assumed the sun was born alone.

But startling new evidence suggests

We may have gotten that wrong, too.

Harvard astronomer sarah sadavoy

Studies star nurseries.

These are the vast clouds of gas

Where star birth is still going on today.

Sadavoy: Ultimately what we want to understand is how stars form.

How do planets form? How do solar systems form?

And it's a long process, and so we need to look at

A number of different observations

In order to really pick out

What's going on at different stages.

Narrator: Her primary target is this -- the perseus cloud,

An enormous haze of gas and dust,

And a fertile birthing ground for sun-like stars.

The perseus molecular cloud is like the perfect laboratory

To look at star formation.

It's nearby.

It's only 750 light-years away,

So very, very close to us.

It's a really active cloud,

So it's got lots and lots of star formation

Ongoing within it, and it's also a star forming region

That's forming stars very much like our own sun.

Narrator: Deep within the perseus cloud,

Star birth takes place inside the densest patches of gas.

Sarah calls them "cocoons".

She uses one of the world's most powerful telescopes

To map out these cocoons.

The james clerk maxwell telescope on hawaii.

Sadavoy: This is a dust map showing where dust is located.

It's a three color image indicating

The different temperatures of the dust,

So, red corresponds to colder dust

And blue corresponds to warmer dust.

So, you can see, here are all of the little cocoons

Where young stars are going to form out of.

Just for size reference, our solar system

Would fit inside each of these little cocoons.

Narrator: Once she's mapped them out,

Sarah turns to the mighty vla radio telescope in new mexico.

She uses it to gaze deeply into each cocoon

And reveal if it's hatching a single star, or a binary pair.

Sadavoy: What I did was I took radio observations,

Looking at all of the young stars

In the perseus molecular cloud,

And I combined that with observations

Of all of the dense cores,

The cocoons that these young stars formed out of.

So, you've got the black corresponding to the core.

That's where the dust is located,

And then you've got these white stars

That are labeled that indicate

Where the young stars are found.

Narrator: What sarah finds is astonishing,

And it raises new questions

About the birth of our sun.

♪

♪

Narrator: With the help of a powerful radio telescope,

Harvard astronomer sarah sadavoy

Peers deep into the perseus cloud

To find out more about how sun-like stars are born.

What she sees is remarkable.

Diving into the perseus cloud

Reveals a stellar birthing ground.

Deep within is a strange bean-shaped cocoon of gas.

Inside, a newborn star.

But it's not alone in its cradle.

A mysterious second body dances alongside it,

A partner star.

Spinning inside their shared birthing cocoon,

These stellar twins are not unique.

Lifting the lids on all the cocoons

Reveals that out here, no sun-like star is born alone.

The upshot of sarah's study is jaw-dropping.

If every sun-like star is born with a twin,

Perhaps our star was born with a twin, too.

Sadavoy: What we find with these models is that all stars like our sun

Likely formed in binary pairs

So that they had a companion when they initially formed.

And in the case of our solar system,

Something happened and our sun no longer has its companion.

This study showed that every sun-like star was forming,

Every single one, was in a binary system,

But yet, here our sun is without a binary partner.

Narrator: The idea of two stars in our solar system

Sounds like a science fiction dream,

But would the earth and life itself

Have evolved to see the wonder of a double sunrise?

Unfortunately, the chances seem slim.

If the sun was actually part of a binary system,

Things would be radically different,

And it raises the question --

Would there be life on this planet?

Would this planet be here?

Narrator: Although planets can exist around binary stars,

The earth may have been a very different place

If the sun had kept its twin.

The combined heat from two stars

Would've roasted the young earth,

Perhaps boiling away the oceans

And creating a crushing acidic atmosphere.

Surface temperatures would've soared.

Life as we know it would've been impossible

In this hot, toxic hellhole.

In a sky full of double stars,

It seems like our small blue planet may have gotten lucky.

And if that's true, how did we lose our companion?

Narrator: Could the chaos of the sun's early years be to blame?

One possible scenario could've played out

Inside the sun's stellar nursery.

Over 4.5 billion years ago,

Inside a stellar nursery,

Hundreds of gigantic birthing cocoons

Are busy incubating stars.

Inside one of them is our newly-formed infant sun.

As it swirls its way through the stellar dust,

A second star comes into view -- the sun's twin.

An immense, second cocoon passes by,

And its massive gravity rips our sun's twin

From its cosmic cradle

And throws it out into the wilderness of the cosmos.

Sadavoy: The more likely situation for the sun

Is two stars splitting apart,

Getting flung off into different directions

Within our own galaxy.

They're now millions of millions of miles apart.

There is no way to tell which star in the night sky

Is our companion star, or was our companion star

Back in the day

And likely we are never to meet it ever again.

Our sister star that formed right with us

Could be clear on the other side of the galaxy.

Narrator: Piece by piece, astronomers attempt

To rewrite the birth story of our home star -- the sun.

But what about the planets?

Do they hide a secret history, too?

The history of the solar system

Isn't as neat as -- eight planets formed

And now, they're the same eight planets today.

The early solar system was very much different

Than the solar system we now live in.

Narrator: And could a rare mineral

Reveal a new history for how the earth

Came to be the perfect oasis for life?

♪

♪

Narrator: Planet earth is bathed in warmth,

As it orbits close in to our mother star, the sun.

The size of our planet is perfect for gravity

To attract a thick atmosphere

And allow oceans of liquid water to pool on the surface.

For us, it's paradise.

But how many other worlds just like it are out there?

Scientists look to distant stars,

Hoping to find similar warm, wet planets.

What they find is shocking.

In the region where the earth sits in our solar system,

Astronomers find a very different type of planet.

When we look around the galaxy,

We see that the most common type of terrestrial planet

Is what we call a super-earth.

The term super-earth refers to a planet --

A solid planet -- that is somewhere between

Three and five times the mass of the earth,

And amazingly, these are the most common types of planets

In the universe.

Narrator: Super-earth planets are so common around sun-like stars

That astronomers now think our ancient solar system

May have had a family of super-earths, too.

This long-lost family of worlds

Would've orbited close in to the sun.

So close that some of their surfaces

Could've seethed with molten rock.

Today, large super-earths

Are nowhere to be seen in our solar system.

But if we did have them, where did they go?

And how did the earth and other rocky planets

Come to take their place?

The answer could lie in the chaos

Of our fledgling solar system,

When newborn planets were jostling

For their position in the cosmos.

Plait: These things were in all different orbits,

Elliptical orbits and they would get close to each other,

And so you were constantly seeing

Collisions between these things.

It wasn't like cars on a racetrack.

It was more like a demolition derby.

There were planets that probably got ejected

From the solar system entirely. There may have been planets

That were actually thrown into the sun.

Narrator: But were these mythical super-earths

Really destroyed this way?

A new theory suggests that jupiter,

The largest planet in our solar system,

May have been responsible

For sending the super-earths to their doom.

Today, jupiter sits almost 500 million miles from the sun,

But in the early days of our solar system,

Jupiter most likely migrated in towards the super-earths.

This trajectory creates cosmic carnage.

There's evidence of migration of some of the giant planets

In other solar systems, and so we think

That that same kind of process

May have happened in our own solar system.

Narrator: This is the theory --

4.5 billion years ago,

Jupiter spirals inwards through a young solar system.

Its immense gravity smashes the forming planets together,

And snowplows their corpses toward the sun,

Piling up a gigantic ridge of rubble.

♪

The pile of rubble meets the family of super-earths.

It disrupts their orbits.

Eventually, they collide,

Causing a planetary pileup that annihilates the super-earths

And leaves a cosmic wasteland in their wake.

Is jupiter really responsible

For the death of the super-earths?

♪

In switzerland,

Scientist farhang nabiei searches for evidence

That long-lost planets once roamed our solar system.

Farhang studies a fragment of the almahata sitta meteorite --

An 88-ton space rock

That exploded over the nubian desert in sudan.

This rare meteorite is thought to have formed

In the very early years of the solar system,

Perhaps even before the earth itself was born.

Tiny gemstones inside the meteorite

Offer a clue for where the rocks were formed.

These meteorites are from the stony family of meteorites,

So they are basically full of rocks,

And then one of the peculiar characteristics of them

Is that they have diamonds,

And diamonds, to form, they need high pressure,

So they should be really deep inside the planet.

Narrator: It's impossible for diamonds like these

To form inside small asteroids.

It takes a rock the size of a planet

To create the pressures that are needed.

This means the diamonds in farhang's meteorite

Were once part of a young planet that got destroyed.

Finding a diamond inside of a meteorite

Means that that meteorite was once under high temperatures

And high pressures,

And that could only occur inside of a planetary body.

If this object is then broken up by a catastrophic collision,

Those diamonds can be incorporated

Into an asteroid, a small asteroid.

Narrator: Are these diamonds a relic

From a long-lost super-earth?

Farhang looks inside the diamonds themselves

To see if there are clues

To the size of the planet they came from.

Nabiei: When diamonds are forming, they trap minerals inside,

And those things are called inclusions.

It's like when you are freezing water,

You put a small piece of stone.

At the end, you have that inside the ice.

You want to cut out those diamonds

And look at those inclusions and study

And see what we can know about this ancient planet.

Narrator: Different minerals form at different pressures.

If farhang can identify the raw materials

Trapped inside these diamonds,

He'll know the size of the planet that they were formed in.

The only trouble -- the mineral grains are tiny --

As fine as a human hair.

Luckily, farhang has access

To a multimillion-dollar microscope --

One of the most advanced of its kind in the world.

So, this is the transmission electron microscopes,

Similar to, lets say, biological microscope.

Instead of light, it's electrons going through the sample.

And here's the sample that we are gonna insert inside.

♪

Narrator: Moments later, the results are in,

And they reveal a surprise.

The planet should be at least about mercury- to mars-sized

To have such a pressure in its interior

And form these inclusions in diamonds.

Narrator: The diamonds are unlikely to have come

From something the size of a super-earth.

But could their planet of origin

Have become part of the rubble pile created by jupiter?

Nabiei: These meteorites, they have characteristics

That shows that probably it has formed somewhere quite close

To jupiter, but in the inner side of jupiter,

Closer to the sun.

Narrator: Farhang's incredible analysis

Proves that our solar system had at least one long-lost planet.

We'll have to wait for evidence

Of the mysterious super-earths to immerge.

But if they did exist, one question still remains --

How did the earth and other rocky planets

Come to take their place?

♪

♪

Narrator: As scientists continue to rewrite the story

Of the birth of our solar system,

They search for evidence of long-lost super-earths.

Did they exist, and, if so,

How did the earth and other rocky planets take their place?

One theory holds jupiter responsible.

After 100,000 years of wreaking havoc in the solar system,

Jupiter finally moves away from the sun,

Leaving a trail of devastation.

The super-earths are gone, burned up in the sun,

But the ridge of cosmic rubble that jupiter piled up

Can now start flattening out.

Inside it, rocks collide and merge to form new planets --

Mercury...Venus...And earth.

None of them are as big as the super-earths they replace.

But these lumps of hot rock will go on to form the heart

Of the solar system that we know today.

All thanks to jupiter destroying the first generation

Of super-earths.

Right now, it's only a theory,

But it may be that we don't just have jupiter to thank

For clearing the super earths out of the way.

The very rocks under our feet

Could be relics from the battle that killed them.

Through a process of collisions,

Planets being thrown out of the solar system,

Planets being thrown into the sun,

We ended up with a situation where what we call earth

Is really perhaps the remnants of early super-earths

And other broken-apart terrestrial protoplanets.

Tremblay: If all of those billions of years ago,

Jupiter hadn't carried out its colossal inward journey,

Our solar system could look completely different.

In fact, it might look like the other solar systems

We see beyond own.

For example, maybe our earth would instead be a super-earth.

Narrator: Scientists are writing a brand-new birth story

For our solar system.

Born inside the shell of a giant star,

The infant sun was ripped from its twin

By a passing cocoon.

And its first generation of rocky children were destroyed,

Allowing smaller planets like the earth to take their place.

Perhaps all these extraordinary events had to occur

For the earth to form,

Just the right size and just the right distance from the sun

To support life like us.

But for that life to get going,

One final extraordinary event was required.

The young earth needed water.

But where did our planet first get its water from?

For decades, scientists believed that our planet was born dry,

Formed from dry materials.

And our water arrived later,

Most likely from asteroids or comets

Smashing into the surface.

♪

One of the oldest questions we've had about earth is,

Where did all of this water come from?

We thought that perhaps it came to earth in asteroids

Or comets, and for sure, some probably did.

Narrator: Now, new evidence suggests this dry earth hypothesis

Could be completely wrong.

Geophysicist steve jacobson

Is convinced the rocks that came together to form the early earth

Were already wet...

...And much of this primordial water

Remains still trapped in the ground beneath our feet.

Steve has spent his career trying to prove

His controversial theory.

He studies a deep layer of our planet

Called the transition zone,

Located about 370 miles below the surface.

Jacobson: I study a part of the earth's interior

That we can't visit.

It's much too deep in the planet,

And so it's pretty difficult being a geologist

That can't do field work.

Narrator: Steve believes this deep layer of our planet

Is full of a rare mineral called ringwoodite,

Which acted like a chemical sponge when our planet formed,

Soaking up the earth's primordial water.

In the transition zone, it's possible that ringwoodite

Could contain more water than is found on the earth's surface.

Narrator: Steve's about to put his controversial theory

To the test.

♪

♪

Narrator: At the argonne national laboratory in illinois,

Geophysicist steve jacobson is about to make a sample

Of the rare mineral ringwoodite

And find out if it can absorb any water.

He suspects ringwoodite is made when a common earth rock

Called olivine is subjected to intense pressures,

Like those found in the greater depths of the earth's interior.

Jacobson: The most interesting thing about ringwoodite

Is its ability to store hydrogen and oxygen,

The components of water.

Narrator: Steve wants to know how much water

The earth's supply of ringwoodite could be hiding.

To find out, he takes a powdered sample of olivine

And adds water to it.

The sample is now placed at the center of this assembly,

Made of tungsten carbide cubes, which are gonna transfer

The force from the press to the sample.

Narrator: Steve subjects the mixture

To the pressures found deep in the transition zone.

These are 300,000 times higher

Than the pressure found on the earth's surface.

Jacobson: In the same way that ice can be made from water

When we change the temperature,

When we change the pressure, minerals can transform

Into new minerals.

Narrator: The 1100-ton hydraulic press transforms the olivine sample

Into a microscopic grain of ringwoodite.

Jacobson: What's gonna come out of the experiment

Is no longer olivine.

It's going to be ringwoodite.

Now, that ringwoodite may or may not have absorbed the water

That we put into the starting materials,

And that's what we're gonna find out next.

Narrator: With his sample made, steve just needs to determine

How much water the ringwoodite soaked up.

He places the sample in a spectroscope

And fires a fine-tuned laser beam to coax out the water

Trapped inside the tiny, blue-colored crystal.

Jacobson: When we change the pressure

And we change the temperature, using lasers,

The water appears to come out of the ringwoodite.

Narrator: But how much water does the ringwoodite contain?

We found huge amounts of water inside it.

This peak represents --

Probably 1 or 2% of the crystals weight is water.

Narrator: 2% may not sound like much,

But there's a whole lot of ringwoodite deep below our feet.

Jacobson: Now if ringwoodite throughout the earth's mantle

Contained this much water, it would be equivalent

To three or four times the amount of water in the oceans.

Narrator: Amazingly, steve is convinced

That this hidden water supply is as old as our planet,

Proving the earth was born with water.

This is too much water

To have been added to the mantle over geologic times,

Suggesting that the earth started off

With quite a bit of water from the beginning.

Narrator: Steve's theory allows scientists

To write a brand-new birth story for the earth's oceans,

One where they are filled from below, as well as from above.

♪

Nearly 4.4 billion years ago,

When young earth is parched and barren,

Hidden roughly 370 miles beneath its crust,

A vast layer of ringwoodite crystals

With enough water trapped inside

To fill our oceans many times over.

Heat rising from the area below forces the crystals upwards,

They melt and release water,

Creating fast-rising plumes of magma

That explode onto the surface.

Here the water condenses and rains down onto earth,

Filling up the newly-formed oceans.

Plait: Most of the water on the earth isn't even on the surface,

It's locked up in the mantle.

We didn't know that a few years ago, and now we do.

That changes our ideas about where water came from.

So there's always the possibility

That some new observation, some new evidence

Will come along and show, "hey, we're wrong."

Tremblay: If it turns out that rocky planets like the earth

Can form with water already in them,

That could suggest that there are a lot more

Water-rich planets out there than we originally thought.

Narrator: Chapter by chapter, scientists are rewriting

The birth story of our solar system.

But as technology develops and new ideas come to light,

How long will it be before the next revision

And the next after that?

This is what's really exciting about the process of science,

Is that there's always something new

That can lead us in directions that we never even imagined.

The basic process of scientific discovery

Is looking at how things are, finding small problems,

Small chinks in the armor of current theory,

And using them as a wedge to break that theory apart,

Come up with new ideas that radically enlarge

The arena of reality that we understand.

Narrator: The birth story of the solar system

Is a story that we should revise again and again.

Because it is the story of us,

And the better we understand that,

The better we understand our place in the universe.