Original subtitles

Did you ever stop to wonder where your car came from?

I mean, really came from?

Every component has a mind-blowing backstory,

an epic journey through time and space

filled with the most violent events since the big bang.

The history of your car is the history of the universe.

How old is your car?

My car is about 5 years old.

My car was assembled in 2001.

The car I drive is pretty old. It was manufactured in 1991.

But that's just when the pieces and parts were assembled.

To find out how old a car really is,

we need to take a trip back to the beginning of time.

Your car began its life billions of years ago,

billions of miles away in deep space.

The things that make up cars, those atoms, most of them

were forged well before our Earth was born.

You think your car is a clunker?

It's actually 13.8 billion years old.

All right. Let's do it, sir.

So, what's the stuff that cars are made of?

Best way to find out... Tear one apart.

Iron, plastics, oils and rubber are the first to go...

In another half hour or so,

this baby's gonna be completely stripped.

I can't wait to see it.

Then aluminum, silicon, copper.

And finally, precious metals,

like platinum and gold.

Each of these materials is crucial for building a car.

But in the earliest days of the universe, none of them existed.

13.8 billion years ago,

time and space are created in the big bang.

The early universe is filled with nothing but energy.

After the big bang, it was just a chaotic glob of stuff,

nothing like what you see today.

As the early universe cools,

the energy gives way to unstable matter and antimatter,

then protons and neutrons and, finally, atoms.

But none of them are iron, silicon or carbon.

The vast, gassy clouds are mostly hydrogen.

Something had to happen to give us everything else.

And everything was actually made

from hydrogen building blocks.

An atom of hydrogen is the simplest and lightest

atom in the universe,

just a single positively charged proton

bound to a single electron.

The universe then builds up bigger atoms like carbon

and iron by fusing hydrogen atoms together.

Everything starts from simpler origins.

An iron atom is actually lots and lots

of simple hydrogen atoms that were stuck together.

At first, this versatile proton building block

doesn't want to stick.

Protons are positively charged.

So as you push them closer together, they're gonna resist

coming closer together.

They really don't want to hang out.

This repulsion makes the early universe

a maelstrom of hydrogen atoms swerving to avoid each other.

But if you can get them to a point where you can

shove them together enough, at some point,

they're gonna lock together.

Pushing atoms together so strongly they stick

is called nuclear fusion.

It's the first step for turning a universe full of gas

into one filled with the ingredients for planets,

people, and cars.

So, how do you get two atoms to fuse?

This guy's been doing it in his garage since he was 14.

Taylor Wilson is obsessed with nuclear fusion.

Yeah, the neighbors know about the radioactive stuff

that's in the garage.

And so does the government.

It's all relatively low level.

That's my watch going off.

I think I'm the only person I've ever met

with a geiger-counter watch.

The centerpiece of Taylor's nuclear man cave

is this precision-engineered fusion reactor,

which he built when he was still in high school.

Okay, I'll let in some gas now.

The first ingredient... Hydrogen gas.

And it will be flowed into the chamber through this very

precise sapphire leak valve.

The next ingredient... High-voltage electricity.

Hmm.

Oh, I wonder what the problem is.

- Power su... - You probably want to plug it in.

Power supply is not plugged in. Okay, let's try that again.

That's embarrassing.

I'm getting power from the laundry room now.

Taylor passes a high voltage through a small, spherical cage

that sits inside the reactor.

The negatively charged cage

quickly draws the hydrogen ions inside it.

So it's taking all those ions

and sucking them towards the center.

And as they fly in they get confined,

and hopefully they collide with each other and fuse.

The temperature of the atoms inside the cage is now so great

that hydrogen atoms are fusing together,

creating heavier helium atoms and a burst of energy

hotter than the surface of the sun.

It's that little, tiny blob of plasma inside those grid wires

that's kind of like a star in a jar.

13 billion years ago,

the universe uses gravity to fuse atoms

instead of an electrical cage.

Across the cosmos, vast clouds of hydrogen gas

collapse under their own gravity.

Pressure and temperature build

as more and more gas gets sucked in.

Eventually, fusion sparks deep in the core

of these giant balls of gas,

and the first stars start to manufacture

many of the heavy elements that make up your car today.

A star is basically a machine for turning lighter elements

into heavier elements.

Fusion takes place only inside the core

of these first stars,

fusing hydrogen atoms together to create helium.

And when all the hydrogen in the core is used up,

the star finds new fuel to burn.

After you burn hydrogen to form helium, the core of the star

begins to collapse and get hotter.

And there is enough energy then to fuse three helium nuclei

into carbon.

And then that fuses to form nitrogen, oxygen,

silicon, iron.

But this incredible production line of elements

can't go on forever.

The heavier atoms you ram together,

the less energy you get out.

So you turn hydrogen into helium.

Helium becomes carbon, nitrogen, oxygen.

But every time there's a bit less energy to be had

until you get to iron.

The iron that is in your car is actually essentially

a deadly poison when it comes to a star.

It's robbing that star of the heat needed to keep itself up.

So the star collapses, dies, and explodes

at the moment you create iron in the core.

I mean, literally the fraction of a second.

I'm not kidding.

That's how dramatic and weird the steel in your car is.

The explosion, called a supernova,

is one of the brightest and most violent events in the universe.

It releases enough energy to dwarf what the sun puts out

over its entire lifetime.

And all of the elements that it has created are then dispersed

out into space.

The gassy remains of the explosion are called

a supernova remnant,

an expanding bubble of hydrogen gas

from the outer layers of the star that mixes with stardust,

the carbon, oxygen, silicon and iron from its core.

And this same 13-billion-year-old stardust

helped you drive to work last week.

This was once in the core of a dying star.

And who knows?

Maybe some of the iron atoms in this brake disc

were forged in the heart of the very first generation of stars

that illuminated the universe.

When you're pumpin' iron, you're pumpin' a universe.

The first generation of stars created the materials in a car's

chassis, body, windshield and seats.

But we're still missing key components, like the copper

for the car's electronics.

To create this crucial metal, a new generation of stars

must die an even stranger death.

Picture our universe as the very first stars

come to the end of their lives.

The early milky way is filled with flashes

as star after star explodes.

These violent supernovas hurl a rich cocktail

of heavy elements into space,

the carbon, silicon, aluminum and iron atoms

that will one day build our cars here on Earth.

But take a closer look at today's cars,

and there are many more elements heavier than iron,

like copper in the wiring

and gold in the connectors.

How did the universe create these heavy metals?

In the case of copper, the answer is reincarnation.

Copper is one metal that your car can't live without.

Turns out there's over a mile of copper in the average car.

And the reason why is because copper is an excellent

electrical conductor.

Copper's also used to conduct heat in radiators.

It stops bearings from failing when you need to go fast.

And when you need to stop, copper provides the friction

in your brake pads.

But the story of how that copper came to exist

and be on Earth, that's a truly remarkable story.

Copper begins with the death of a first-generation star.

The expanding supernova remnant slams into neighboring clouds

of gas, creating a shock wave of pressure,

giving birth to a new generation of stars.

There are cycles to the universe.

Stars form. They live out their lives.

They die. They blow off winds

and they explode, ceding their material into gas clouds

which then form new stars with heavier elements in them,

which will repeat the cycle again.

So if you want to think about it that way,

the universe is the ultimate recycler.

The hydrogen gas that forms these

second-generation stars is peppered with the carbon,

aluminum and iron thrown out by the supernova remnant.

The biggest of these dirty stars burn brightly

for a few million years.

Then they undergo an incredible metamorphosis.

The star grows suddenly to 100 times its previous size.

Then it cools and turns a ghostly red.

The second-generation star has transformed

into a red supergiant.

And it's in these diffuse outer layers that iron-rich stardust

is slowly converted into copper...

But not by fusion.

That iron nucleus has 26 protons.

That's a serious electric charge.

So it's gonna repel any protons we try to shoot in there.

How do we get more protons in?

The way we get those protons in there is we trick the nucleus.

Instead of shooting in protons, we shoot in neutrons.

Colliding atoms in the outer layers of a star

sometimes spit out neutrons.

Neutrons don't have a charge, so they're not repelled

by the positively charged protons in the iron stardust.

So these neutrons can stick to the other atoms around them.

An atom is a very tiny thing. It makes a very small target.

But there's a lot of particles flying around near a star.

And if, by chance, a neutron can hit an atom, it can stick.

And that will actually make the nucleus of the atom larger.

Neutron by neutron can hit an atom.

And then that neutron can actually decay into a proton.

The neutron spits out an electron,

and what's left is a proton and a new, bigger atom.

In this case, copper.

Scientists call this magical transformation beta decay.

So you can build up heavy elements very slowly

over the course of thousands or millions of years

just by capturing neutrons.

Eventually, the core of the red supergiant

runs out of fuel, and the star explodes,

blasting its copper-rich outer layer into space.

Thanks to the life and death of two generations of stars,

we can now equip our car with copper wiring.

But we're still short of some even heavier metals,

such as lead for the battery

and gold for the electrical connectors.

To make these truly massive atoms, the universe must create

the most spectacular explosions since the big bang.

To make a car, you need some seriously heavy metal.

Take iridium, a super-tough atom with 77 protons

that's used to coat the tips of spark plugs.

Next on the heavyweight lineup comes gold with 79 protons.

This shiny conductor resists corrosion, making it ideal

for exposed electrical connections.

These connectors here for this airbag assembly are gold.

And so this thing can react really quickly

if there is an accident and save your life.

The biggest atom in a car is lead with 82 protons.

Only lead has the durability to deliver the short burst

of high power needed to start an engine over and over again.

But until very recently, how the universe made these

oversized atoms was a complete mystery.

You can't make gold atoms in a normal star.

You can't make gold atoms in a massive star that's dying.

In order to make atoms this big with this many neutrons,

you need a truly cataclysmic event.

Just a few years ago, most scientists believed

that supernovas were cataclysmic enough to do the job.

But astronomer Edo Berger was not so sure.

If you open any one of these books and flip to the page

that tells you where gold came from, it will tell you

that gold came from supernova explosions.

But nobody had directly observed supernovas

producing elements like gold.

And inside computer simulations, virtual supernovas

lacked the energy to forge these oversized atoms.

Clearly, something was wrong.

But if supernovas weren't powerful enough,

what in the universe was?

To form heavy elements requires a lot of neutrons.

And so another possible theory was that the heaviest elements

were produced in the mergers of two neutron stars

in a binary system.

Neutron stars are some of the weirdest objects

in the universe.

They're formed from the collapsed cores of big stars

when they die.

You're taking a couple of times the mass of the sun

and squeezing it down into a ball

that's only a few miles across.

The electrons and the protons that are flitting around

inside of that combine to form neutrons.

And what you're left with is an extremely dense ball

of neutrons about the size of a city.

Neutron stars are extremely dense.

If you take just a teaspoon of the neutron star material,

it's actually a billion tons.

If neighboring stars die together,

it's possible for the two neutron stars they leave behind

to form a spinning binary pair.

But the partnership is doomed.

What you're left over with is two incredibly

compact dramatic objects spiraling around each other.

Over time they move in together,

until finally they can coalesce

in the most violent explosion since the big bang.

The explosion is called a neutron star merger.

The amount of energy in this explosion is crushing.

There is almost no way to describe it.

It's like taking all of the sun's energy

that it will ever emit over its entire lifetime

and releasing it in a single second.

Berger suspects this colossal explosion

forges iridium, gold and lead.

But to rewrite the textbooks, he needs hard evidence.

It was difficult to, uh, convince the community that this

was a potential channel for the production of heavy elements.

The proof is to actually see this process happening

in the universe.

June 2013...

NASA's swift satellite spots a short burst of gamma rays

from a nearby galaxy,

a sure sign that a neutron star merger has just taken place.

For Berger, it's the lucky break he's been waiting for.

As soon as we knew that there was

a gamma-ray burst nearby,

we knew that this was our one chance for perhaps several years

to obtain the right kind of measurements

to test the formation of heavy elements.

Once swift had identified the burst,

the hubble space telescope swung into action to capture images.

We grabbed them right away, and we just looked.

We knew exactly where to look...

At the center of this red circle.

And what we saw was this source right there in the middle

that is the direct signature of the production

of very heavy elements, including gold.

Berger's theory was right.

But the rate of production was way higher than he'd expected.

Well, in that one event,

the amount of gold that was produced

was more than the mass of the Earth.

If we can bring it all here, it would be worth

quadrillions and quadrillions of dollars.

The theory is still very new,

but it's possible that ancient neutron star mergers

made all the heavy metals we see in the world today,

including the last remaining ingredients for our car.

But all these elements are still floating free in space.

What's needed now is to pull them all together

into one giant fabrication plant...

The Earth.

This is what your car looked like

before the Earth was born...

Just a vast, swirling cloud of gas and stardust,

the exploded remains of ancient stars.

The clouds between the stars of the galaxy

are made of everything that the Earth,

your body, and your car is made of.

There's everything that you need floating in gaseous form

between the stars.

Four and a half billion years ago,

the gas and dust collapse once more.

It ignites explosively to create a new star... our Sun.

Close to the young Sun,

all of the lighter stuff got blown away.

What was left behind was the heavier, denser stuff.

There was carbon. There was iron.

There was gold... Everything in between.

Over time, these free-floating elements

begin to coalesce.

Dust becomes rock.

Rocks join to form larger objects called planetesimals.

Finally, planetesimals joined to form the Earth.

Our planet is born with all the ingredients to build a car.

But those ingredients are about to go their separate ways.

The Earth is a big planet.

And it's done something that not all planets do...

It's differentiated. It melted.

Copper and lead dissolve in sulfur

and float to the top of the molten Earth,

making these metals easy to mine today.

But precious metals like iridium and gold

sink to the core of the Earth,

and most of the iron sinks with it.

It's kind of a pain, actually. All the heavy elements

that are super useful, like iron,

they've sunk to the middle of the Earth,

where we can't reach them.

And there's not a whole lot of it in the crust.

3.8 billion years ago, the oceans form,

and water dissolves the last remaining traces

of iron from the Earth's surface.

In fact, there was so much iron in the sea

that the Earth would have been green,

not blue like it is today.

The Earth's crust seems destined to be

practically iron-free.

Then, along comes the most unlikely savior... green slime.

I want to show you a couple of examples of rocks

that we recently brought back from South Africa.

Caltech geobiologist Woody fischer

traces the history of iron

through the Earth's earliest rocks.

This is an example of a rock that was deposited

on the sea floor a little over 21/2 billion years ago.

And there's not a lot of iron in this sample.

Now what's so interesting is, you go to the same place

on the Earth 200 million years later,

and what you find is that things have really changed.

And you'll note this very rusty color to it.

This is from the presence of iron oxides.

And in fact the rock itself is incredibly heavy, very dense.

Why does the Earth's geological record

change so quickly and so profoundly?

One clue is that the sudden appearance of iron-rich rocks

coincides with the rise of the first simple plants.

This is a micro-organism called a cyanobacterium.

Each of the individual cells that are present in that medium

are green, and they're conducting photosynthesis.

This group cyanobacteria is gathering energy from light,

using that to split water.

And in so doing, they produce copious amounts of oxygen.

In the early oceans, this newly formed oxygen

quickly binds to the dissolved iron,

forming a heavy rust that settles on the ocean floor.

For the first time in Earth's history, there was oxygen...

Free oxygen in the air. That combined with the iron.

And the iron basically sank to the bottom of the ocean.

These ancient, rusty deposits

formed the iron ore we dig out of the ground

to make cars 2 billion years later.

So in the process of making a car,

mining the iron ore,

life was an essential part of that first step.

You have to wait until after these guys evolve

in order to be able to concentrate

the raw materials that you need.

The life of early plants brought us iron.

But their death is perhaps even more helpful

because without dead plants, your car isn't going anywhere.

So, what's the final ingredient

for getting a car to actually go?

You need to add fuel.

And we, right now, use hydrocarbon-based fuel.

We use oil.

Oil is actually the remnant of dead plant life

from billions of years ago.

It amazes me to think that, as you're driving your car around,

what you're actually running the car on is ancient dead life.

These hydrocarbons are also processed

to help make rubber and plastics for the tires and interior trim.

Now we have almost all of the components needed

to complete a car.

All that remains is a spark to bring the engine to life.

But to get that spark,

the Earth must pay a catastrophic price.

65 million years ago,

the Earth's crust had all the materials needed

to build a car except for one crucial group

of supertough metals.

This is a spark plug.

And the way it works is that 100,000 volts are put across

this gap here.

And that ignites gasoline vapor in the cylinder of your motor.

This tip has to survive in very harsh conditions.

So it must be made of a very, very sturdy, robust material.

And the material in this spark plug

is a metal known as iridium.

Like other heavy metals such as gold and lead,

iridium is born inside the exploded remains

of neutron stars.

And when the Earth forms, plenty of iridium is in the mix.

But it quickly sinks out of reach

while the Earth is still molten,

falling to the core under the influence of gravity.

So, where does the iridium come from that we mine today?

This exposed rock face in Colorado reveals a clue,

a mysterious layer in the Earth's geological record

that wraps around the entire planet.

There's something particularly interesting

about this Clay layer here.

If you analyze the concentration of rare metals

like iridium in this layer,

you'll find that there's about 100 times as much iridium here

as in the other rocks around us in the crust of the Earth.

It's rather bizarre, actually, to find so much iridium

concentrated in one place here in crustal rocks.

And it turns out that the entire budget of the iridium

in the Earth's crust is pretty much contained in this layer.

When geologists discovered the iridium layer

in the late '70s, it became one of the biggest

mysteries in science.

How could so much of this rare metal end up

concentrated in such a thin layer?

Only astronomers had measured such high concentrations

of iridium before, inside rocks

originating in the asteroid belt.

Billions of years ago, planets were forming

all over our solar system.

But there was an area in between Mars and Jupiter

where the gravity of Jupiter pretty much pulled apart

anything that tried to form.

And what got left over were a bunch of large, rocky chunks

that we call the asteroid belt.

Now, some of the asteroid belt is made of rock.

Other asteroids are richer in metals.

From time to time,

asteroids can get thrown out of orbit

by another asteroid, or by the long reach of Jupiter's gravity.

And sometimes, they smash into the Earth.

Is it possible the iridium layer was simply

the scattered remains of a single, giant

metal-rich asteroid impact?

30 years ago, this sounded like a crazy idea.

Only an asteroid the size of a city

would have had enough power

to blast debris around the entire planet.

If you can imagine the magnitude, the enormity

of the violence of an event like that,

and to have inches of dusty debris

come booming over the horizon and settling out of the sky

and raining on top of you and burying you in this layer,

that should make a pretty big crater someplace on the Earth.

Although it sounded crazy,

the asteroid hypothesis also solved

a longstanding mystery.

The dinosaurs were wiped out around the same time

the iridium layer was laid down.

Could the two events be linked?

The puzzle was solved when an asteroid impact crater

was discovered down in the Yucatan.

The crater age turned out to be exactly 65 million years old,

the same age as this deposit.

And the crater's size turned out to be just the size

of crater you would get from the size of an asteroid

it would take to make this layer.

So it turns out that, in a lot of ways, you can think

of asteroids as sort of a cosmic iridium-delivery system

for us here on the surface of the Earth.

And it's not just iridium

we have to thank asteroids for.

There were probably several times

in the history of our solar system where there was

heavy bombardment, all kinds of asteroids and comets

falling in towards the Earth.

Well, the Earth had solidified to some degree by that time.

So not everything sank down into the core.

So some of the metals we find around us

are products of this later era of bombardment.

The Earth's history is a violent one.

Over the course of time, we have been hit over and over

and over again by asteroids of all sizes.

Some of them have actually delivered quite a bit

of heavy elements to the surface of the Earth.

These asteroid-borne materials

include most of the gold, platinum and nickel

we use in cars today.

Asteroid impacts will form little pockets of concentrations

of some of those ore minerals and ore metals for us

that we can then mine in greater abundance on the surface.

In many cases, when you go to a mine to dig up

these heavy elements, what you are doing

is tapping into an asteroid impact.

Metal-rich asteroids are the final piece

of the puzzle.

We can now reconstruct the journey of every atom

of our car through time and space

from the moment of the big bang

through generations of stars to the birth of the Earth

and, eventually, the showroom floor.

Over the course of the multiple supernovae

in our universe and the birth and death of stars,

we were able to collect all of the materials needed

to assemble these cars.

That's pretty fantastic.

I think we don't fully appreciate how complicated

the elements that make up our car really are

and how special they are. They really are star stuff.

But not every car is like the one

we've just pulled apart.

These days, not every car runs on gas.

And electric vehicles require a magical element

that's made in space by cosmic ray guns.

This car doesn't have a gas tank.

It's part of a new generation of electric vehicles.

The key to these high-tech cars

are their rechargeable batteries,

a technology that relies on one of the Earth's rarest metals.

This here is a battery pack from an electric car.

And in today's electric cars, the metal of choice is lithium.

And lithium has one of the most amazing stories in the universe.

After hydrogen and helium,

lithium is the lightest element,

with just three protons and four neutrons.

Its lightness makes it ideal for electric cars.

If the battery weighs more than the car, then we are just

wasting energy on moving the battery around.

If we can build a light battery,

for example a lithium-ion battery,

then we can provide the power without the penalty

of having to carry those heavy batteries

along with the car.

Lithium is rapidly becoming

one of the most sought-after metals on Earth.

But it's also a cosmic curiosity.

The big bang creates a trace of lithium.

But as the first stars form, this lithium disappears.

Unlike hydrogen and helium, which are fairly stable

on an atomic scale, lithium is a little bit fragile.

It can actually be broken apart into its components.

As time goes by, these first stars manufacture

a little lithium on their own, but it doesn't last long.

It is so fragile that, the instant it's made,

it's destroyed once again by the conditions

in the core of the star.

So, how does the universe fuse together atoms

to form lithium?

Surprisingly, it doesn't.

It blasts them apart.

The answer for where lithium comes from

is an amazing thing.

It's almost like a Sci-Fi answer.

It kind of comes from ray guns from space.

The ray guns are supernovas.

And their bullets are cosmic rays, high-velocity particles

that streak through space at close to the speed of light.

Cosmic rays are subatomic particles.

They are atomic nuclei that are accelerated to high speed

in a supernova explosion.

If another atomic nucleus gets in the way, it can hit them

and shatter them.

And one of the pieces of shrapnel from this explosion

is lithium.

The process is a bit like going bowling, where the bowling ball

is the cosmic ray, and the pins together are some other

atomic nucleus.

When the bowling ball smashes into the pins,

it sends them scattered in all directions.

And one of those pins could be lithium.

Cosmic rays are traveling throughout all of space,

between galaxies and in galaxies.

So the cosmic rays that are forming lithium

by breaking other elements apart

are literally doing it in the space between the stars.

Almost all the lithium on Earth today

was made this way, atom by atom in the vastness of space,

and then swept up into the clouds of gas

that formed our solar system.

Oh, yeah, baby.

For our cosmic car, this may look like the end of the line.

But the production line for the universe,

that keeps on rolling.

This is pretty awesome.

These atoms in this car here have been traveling

across the cosmos.

They came to us from maybe 13 billion years ago,

a billion years after the formation of the universe.

And now, guess what? They were used,

and we're returning them back to where they came from.

The atoms in our car will not be in our car forever.

In fact, our car will probably be destroyed

within a single human lifetime.

Time to crush.

It'll be recycled into other things on Earth.

But eventually, even the atoms on Earth will be recycled

with the rest of the cosmos.

How cool was that?

You could imagine my car gets destroyed with the Earth,

and eventually it makes its way to another planet.

It gets built into some other kind of transportation mode

by an alien race... I mean, that's totally possible.

And I think that's kind of a cool idea.

From stars being born billions of years ago

to cosmic rays to even the big bang itself,

it's amazing to contemplate all of the things

that had to come together in the universe

for us to have cars.

You really are driving around

in the end product of something that started

13.7 billion years ago.

That new-car smell?

That's actually old-universe smell

because that smell is traceable all the way back

to the big bang.

How you like that?

That guarantees the last word in a... in a show.

Okay, yeah.