How the Universe Works

to a place where the rules of physics collapse.

Imagine a place surrounded by trillions of icy rocks...

Unlock the secrets of earth's first oceans,

and we'll unlock the secrets of alien life.

And the magnetic fields that help stars ignite,

they shape entire galaxies.

And what's going on in its outer reaches determines

whether we live or die.

The first second of the universe has barely begun.

And the shortest possible units of time, planck times,

are flying by in their millionths.

The universe is a super-hot ball of radiation,

billions of times smaller than an atom,

and dense beyond imagination.

Gravity has begun shaping the future of the cosmos.

But as the universe expands, temperature drops.

Another force arrives on the scene, the strong force.

Without the strong nuclear force,

the nuclei of the atoms themselves

would all disintegrate.

Three forces...

gravity, the strong force, and the fractured super force...

rule the universe as it hurdles towards its next milestone,

an event that sets out the blueprint for the galaxies

that fill the cosmos today.

We think this event happened

because it explains a longstanding mystery.

Everywhere we've looked in the universe,

its billions of galaxies are spread evenly,

the same number in every direction.

Nobody could explain why.

All of these parts of the universe must have at one point

been in contact with each other.

It's kind of like having two people

who live on opposite sides of a country

getting up at the same time,

eating the same breakfast, dressing the same way,

even when they don't talk to each other.

There must be something common in their past that links them.

This problem needed a solution.

And in 1979, a young cosmologist named Alan guth proposed one.

He called it inflation.

This was very exciting.

I suddenly realized that this might be the key

to a very important secret of the universe.

But at the same time, I was, of course, very nervous

because it was all new.

And I was shaky about whether or not it was right.

Guth speculated that the infant universe

went through a phenomenal growth spurt.

Cosmic inflation was a moment in the history,

the very early history, of the universe

when the expansion suddenly accelerated.

It got huge for the briefest moments of time.

Just 10 million planck times after the big bang,

a tiny volume of space suddenly starts to expand

much more quickly than before.

This inflation is so rapid that it turns chaos into order,

spreading the constituents of our universe

evenly throughout space

and fixing their positions within it.

As the universe cooled down in those earliest moments,

it increased in volume by a factor of 10 to the 90th,

in a millionth of a billionth of a billionth of a second.

It's like a grain of sand

swelling to larger than the sun faster than the speed of light.

Well, have we violated Einstein's laws?

Nothing can go faster than the speed of light.

And here is one of the real subtle points

about the big bang.

Space can expand so much that two objects appear to move apart

faster than the speed of light.

But they're not moving.

It's the space in between them that's growing.

Guth's audacious idea, the inflationary universe,

could push the limit of our understanding back

to the very first moments of the very first second.

But how could we ever test it?

How could we peer into the birth of creation?

TV static holds a clue.

1% of the static on this screen

comes from light from the big bang.

In 1964, astronomers arno penzias and Robert Wilson

were listening to radio signals from space.

But in every direction,

they were picking up a background hum.

Puzzled by the hum, they suspected they knew the culprit

and swept the entire receiver free of pigeon droppings,

but to no avail.

What penzias and Wilson had stumbled upon

was the afterglow of the fireball

created by the big bang.

As the universe expanded, it cooled.

After a few hundred thousand years,

it was just protons and electrons flying around.

But at some point, the universe cooled enough

that when an electron and proton got together

all over the universe, essentially all at once,

the universe became transparent.

Kaku: Think of a gigantic fog that suddenly lifts.

Before the fog lifts,

you can only see a few feet in front of you.

Then suddenly everything becomes clear.

That's what happened 380,000 years after the big bang.

Ever since that moment,

380,000 years after the big bang,

this light has traveled uninterrupted through space.

Scientists call it the cosmic microwave background.

If you were to write down a handful

of the greatest scientific discoveries of all time,

one of them might be the discovery of DNA.

Another one might be

the discovery of a cosmic microwave background.

That's how big this discovery was.

We once believed creating a star was easy.

Take a huge cloud of gas,

add some gravity,

and stand back as the gravity crushes the gas down

to a hot ball of plasma.

Temperatures and pressures rise until fusion sparks,

and a star is born.

Now scientists think gravity alone is not enough.

To construct a star, you also need magnetism.

The primary mover when you're forming a star is gravity.

The material condenses in the center to form a star,

and as that star forms there's material swirling around it,

attracted to that central mass by its gravity,

but there's a problem.

This stuff has what's called angular momentum.

Angular momentum is the force of rotation

that keeps the clouds of gas spinning around the center

of the forming star.

It works against gravity,

smearing the gas into a thin disk.

Young stars, or protostars,

can only ignite if the central gas cloud

reaches a super hot, dense state.

But the disk spins around the center too fast

for gravity to do its work.

Scientists now understand that a third force

is at at play here.

That's where magnetism can play a role.

The magnetism of the protostar, the forming star,

can actually affect the disk and slow it down

and actually let it drop in and help the star itself form.

The swirling gas in the forming star

and its surrounding disk

generate powerful magnetic fields.

These fields grab the fast-moving particles,

slowing them down.

Bullock: Magnetism works like a cosmic brake.

It slows down a little bit

and eventually spirals into the center.

Gravity stars to win.

Gravity beats out that angular momentum,

and star formation happens.

Gravity drags the slowing disk inwards,

crushing it until the gas gets so dense it ignites.

A star bursts into life.

This is our universe as it looked 12 billion years ago.

The gassy cosmos is filled with flashes

as gravity and magnetism crush clouds of hydrogen gas

to create stars.

Some of the largest of these stars burn through

their hydrogen fuel quickly.

Without the power of fusion,

there's nothing to fight against gravity.

Sometimes this leads to a violent, magnetic death

when the star collapses and implodes in a supernova.

The gassy outer layers of the star blow out into space,

and the core of the star crushes inward,

supercharging its magnetism.

If you look at stars, just about all stars have

strong magnetic fields at their surface.

What happens is that if a star dies and it collapses,

the same amount of magnetic field must still be present.

So if the surface area of the star is decreased

by a factor of 1,000 or 10,000,

then that means that the magnetic field intensity

must increase by that same amount.

As the supernova's core collapses,

the magnetic field's strength keeps building.

At the end of all this, you get a ball 12 miles wide

called a magnetar.

These dense balls have very, very strong magnetic fields.

In fact, the strongest magnetic fields in the universe.

The magnetic field can be more than a trillion times

stronger than the earth's field.

If you got very, very close to a magnetar,

that strong magnetic field might possibly rip you apart

because your atoms just can't stay together

in the vicinity of such a strong magnetic field.

Giant stars with the potential to form magnetars

still exist within our universe.

Scientists know of 23 magnetars within our galaxy today,

and one of these, sgr 1806-20,

located 50,000 light-years from earth,

is the same magnetic monster that unleashed an assault

on the earth in 2004.

The blast was triggered by a starquake.