How the Universe Works

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

Where it really came from?

Every component has been on a mind-blowing journey,

through time, space...

and the most violent cosmic events since the Big Bang.

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

How old is a car?

My car is about five 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.

The materials that make up the cars we drive today

were created long before 1991.

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.

The best way to find out what a car is made out of

is to tear one apart.

Iron, plastics, oils and rubber are the first to be removed.

In another half-hour or so,

this baby's going to be completely stripped.

I can't wait to see it.

Then aluminium, 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,

the universe was born in a monumental event...

the Big Bang.

The early universe was 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 gave way to unstable matter and antimatter.

Then protons and neutrons,

and finally, atoms.

But not the iron, silicon or carbon atoms that we use in a car,

the universe was almost entirely made up of 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 built up bigger atoms such as carbon and iron

by joining hydrogen atoms together.

Everything starts from simpler origins.

An iron atom is actually lots and lots of simple hydrogen atoms

that were stuck together.

But hydrogen atoms don't naturally stick together.

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 going to lock together.

Pushing atoms together so strongly that they fuse

is called nuclear fusion.

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

into one filled with the ingredients for planets,

people and cars.

Getting two atoms to fuse is child's play...

at least it is if your name's Taylor Wilson.

Taylor's been fusing atoms in his garage since he was 14.

Yeah, the neighbours know about the radioactive stuff

that's in the garage, and so does the government.

It's all relatively low-level.

It's my watch going off.

I think I'm the only person

I've ever met with a Geiger-counter watch.

The centrepiece of Taylor's nuclear man cave

is a precision-engineered fusion reactor

which he built when he was still in high school.

OK, 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.

Hm.

Oh, I wonder what the problem is!

You forgot to plug it in. The power supply is not plugged in.

OK, let's try that again. That's embarrassing.

We'll get 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 pulls the hydrogen ions towards 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.

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 used gravity instead of an electrical cage

to fuse atoms together.

Across the cosmos,

vast clouds of hydrogen gas collapsed under their own gravity.

Pressure and temperature built as more and more gas was sucked in.

Eventually, fusion sparked deep in the core of these giant balls of gas,

and the first stars started to manufacture

many of the heavy elements that make up cars today.

A star is basically a machine

for turning lighter elements into heavier elements.

Fusion took place inside the core of these first stars,

fusing hydrogen atoms together to create helium.

And when all the hydrogen in the core had been 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 gas containing hydrogen that survived in the star's outer layers,

mixed in with carbon, oxygen, silicon and iron from the star's core.

This 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 pumping iron, you're pumping the universe.

The first stars created the materials in a car's chassis,

body, windshield and seats.

But key components, like the copper for the car's electronics,

are yet to be manufactured.

To create this crucial metal,

a new generation of stars must die an even stranger death.

Picture the scene 13 billion years ago...

as the universe's very first stars are coming to the end of their lives.

The sky is filled with flashes

as star after star violently explodes.

These supernovas hurl a rich cocktail of elements into space...

carbon, silicon, aluminium and iron,

materials that will one day be used to build cars on Earth.

But some even heavier elements

needed to build a car are still missing.

Elements like copper and gold, used in the car's wiring.

So far, the universe hasn't created these heavy metals,

but it's about to.

In the case of copper,

the secret to its formation is reincarnation.

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

It 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 can't begin to form

until the first generation of stars have died.

The expanding supernova remnants

crash into neighbouring clouds of gas...

creating a shock wave of pressure,

a perfect nursery for 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,

seeding their material into gas clouds which then form new stars

with heavier elements in them, which will repeat the cycle again.

So if you wanna think about it that way,

the universe is the ultimate recycler.

The gas that forms these second-generation stars

is peppered with the carbon, aluminium and iron

thrown out by the supernova.

The biggest of these new stars burn extremely brightly,

but only for a few million years...

then they undergo an incredible metamorphosis.

The star rapidly expands to 100 times its previous size...