I want to take you on a journey.
It's a journey like no other. A journey out there...
Look up at the night sky. What do you see?
The planets, the stars,
a million points of light...
You're looking at your universe.
This series will take you there.
We'll experience first-hand the wonders of the universe, its power and its danger.
And to take a CLOSER look, we'll even bring space down here to Earth.
We'll seek out alien life.
Witness the birth of new worlds.
And we'll discover why what happens out there in space affects all of us here
on the one small planet we call our home.
We'll take you from the beginning of time...
..to the far future of humanity.
This is the voyage of a lifetime. This is the voyage into space.
We begin with the BIG question: where did we come from?
Aliens.
What would you think if I told you that you, me, everyone came from outer space?
Weird though it sounds, it's true - we're all aliens.
Once upon a time, every single thing that makes us what we are came from the stars.
We live in a small corner of the universe.
This is our neighbourhood - the solar system.
At its centre, the sun.
And just 150 million kilometres away is our home: the Earth.
It's an astonishing planet.
The only place we know of in the whole universe where conditions are right for life.
The air we breathe...
Rich seas and oceans...
Our planet is alive!
And what's remarkable is, it shouldn't be!
Life on Earth shouldn't even exist.
So where DID it all come from - me, you, the planet we live on, even our sun?
It's a puzzle because at the beginning none of it was here.
Let me show you what I mean.
This is the moment it all started - the Big Bang.
(EXPLOSION)
And that was it. The Big Bang created the universe,
but a universe containing only a vast cloud of hydrogen gas.
So how did something so featureless create our world? And how did it create us?
The journey from a cloud of hydrogen
to the building blocks of life is extraordinary.
The calcium in my bones, the oxygen we breathe, where did it come from?
It all began at the time the universe gave birth to the stars.
For millions of years, the entire universe
was nothing but the single vast cloud of hydrogen gas created in the Big Bang.
But within the cloud, something amazing was happening.
Shock waves from the Big Bang were echoing through the cloud,
making it billow and swirl.
Huge whirlpools of hydrogen formed, sucking in the cloud that created them,
spinning them tighter and faster to form huge balls of gas.
And as they span, these enormous spheres got hotter and hotter
until the moment came that changed the universe forever.
The first-ever stars were born.
But these stars alone are not enough to explain why WE'RE here.
What turned stars into us?
Beneath the deserts of Arizona is a device which may reveal the answer.
Lawrence Krauss is a physicist, but this isn't a lab he's visiting.
It's a weapons silo.
The closest we've been able to come to that incredible release of energy
associated with the violent birth of a star is with the hydrogen bomb, or the superbomb.
Hidden in bunkers like this is the technology that allows us
to understand what goes on in the heart of a star.
(ALARM BELL)
(SIREN)
It's the most destructive weapon on our planet.
(ALARM)
(CONTINUOUS SIREN)
This is the power of a hydrogen bomb.
It's the same hydrogen that fuels the fire of every star in the universe.
(KRAUSS) I'm standing on the gantry
near the very top of a Titan intercontinental ballistic missile.
A huge rocket designed to propel, at its very top,
a small payload containing the most explosive device ever created by mankind.
The amount of hydrogen gas in an H-bomb is tiny.
It's barely enough to fill a party balloon.
But the energy it can unleash is devastating.
(EXPLOSION)
This is the same energy which keeps the stars alight.
All this is from a single balloonful of hydrogen.
The ball of hydrogen that makes a star is a million kilometres across.
A star releases the energy of millions of H-bombs every second.
(EXPLOSION)
But, far from being destructive, inside the nuclear furnace of every star
there is an extraordinary process of creation.
As I stand here in this silo and look up at the thermonuclear device 100 feet above...
If it were to go off, I and everything in a ten-mile radius would be evaporated.
But it's also likely that almost every element in the universe would be created.
Just as inside stars hydrogen fuses to form helium, which fuses to form carbon,
then nitrogen, then oxygen, silicon, iron...
As I look around me, everything I see was once the inside of a star.
Every atom came from inside of a star.
The universe began with hydrogen.
And hydrogen created the stars.
And the stars created the elements we need for life:
oxygen in the air, calcium in our bones.
It all came from the stars, but how?
If it was created THERE, how did it make our world?
It's astonishing to think all the ingredients to make the Earth and every living thing
were created inside stars.
Every star is an immense factory churning out billions of tons of chemicals.
But the chemicals aren't much use to anybody while they're in there.
Luckily for us, stars don't last forever.
Just occasionally, they explode.
Amazing but true. Entire stars can blow themselves apart.
To understand WHY,
let me take you back to the very last few moments of a star's life,
just as it teeters on the point of destruction.
This is a star that died billions of years ago.
It's huge. Its life has been violent and short.
And its death made our lives possible.
You are about to witness one of the most violent and wondrous events in the cosmos.
The star has run out of hydrogen fuel.
The nuclear fires that have kept it burning for millions of years have gone out.
As it cools, it shrinks.
It starts to collapse under its own weight.
It crashes inwards
and explodes.
The whole event is over in a thousandth of a second.
They call it a supernova,
an explosion so bright it outshines entire galaxies.
Billions of tonnes of star stuff...
..hurtle outwards, into space.
So look at a supernova and you're witnessing a moment of creation.
Even with our most powerful telescopes, these explosions remain frustratingly distant.
The best way to find out what happens when a star dies is up close and personal.
We are now charging. Process...
Ten, nine, eight
seven, six, five,
four, three,
two, one.
(THREE BANGS)
To understand the moment of creation that happens when a star dies,
you have to study the explosion.
So we really ARE mistimed by two nanoseconds?
Paul Drake's job is to recreate the most violent explosion in the universe
in a lab in upstate New York.
It may not LOOK like it, but this is our version of an exploding star in the lab.
Exploding stars release a huge amount of energy.
We can't do that on Earth. We'd blow up the solar system.
What we CAN do is concentrate a great deal of energy into a small volume.
To generate anywhere near the force of a supernova,
Drake uses the world's most powerful laser
and focuses it onto a point smaller than the head of a pin.
Here we are in the laser bay, where the laser meets the tiny target.
We wear these bunny suits to protect the laser.
We wear glasses to protect our eyes from the laser.
The laser's in the room next to us. It's the size of a football field. It's huge.
The energy in that beam is 20 times the amount of electrical energy
flowing throughout the entire USA at any one time.
The target is a tiny tube containing the same materials you'd find at the heart of a star.
When the laser hits this target, that creates a shockwave that's so strong
that it shreds the material inside that tube. It tears the atoms apart.
Inside the tiny target is Paul Drake's version of a star just before it explodes.
The inside of a dying star is made up of layers, like the layers of an onion.
The outer layers are the remnants of the gases that fuelled the star, mostly hydrogen.
Deeper, there are layers of calcium, sulphur, carbon,
and at its heart, a dense core of molten iron.
Drake's tiny target is packed with these same layers - like a slice through a star.
(EXPLOSION)
His aim is to see what happens when a star explodes.
Five...
..four...
..three...
..two...
..one.
(REPEATED EXPLOSIONS)
Here, slowed down millions of times, is what his experiment reveals.
The complex patterns of an exploding star shown in astonishing detail.
The beautiful and precise motions
that scatter the building blocks of life out into space.
That explosion throws the elements that were formed in the star outwards
into the galaxy. Some of them gather together and form other stars,
solar systems, even planets, like the Earth.
These images, captured by our most powerful telescopes,
show the remains of these violent events.
Vast clouds of star stuff expanding though space,
one of the most breathtaking sights in the universe.
But there's a puzzle in these pictures.
It may be the stuff of life, but these are just clouds.
What could turn a cloud into rocks or water?
What could turn a cloud into life?
We've begun to piece the puzzle together.
We've traced the process from the death of a star to the creation of new worlds.
It has taken the most powerful telescopes
and years of patient searching by hundreds of scientists.
One of them is Professor Bob Kirshner.
They call him the godfather of supernovas.
There's a bright supernova once every hundred years or so in a galaxy.
So you're pretty lucky if you see one in your own lifetime.
In 1987, the astronomers' dedication finally paid off.
For the first time, they saw the moment of destruction.
A star exploding. A supernova in a nearby galaxy.
This is Supernova 1987A. We can see parts of this exploding star.
The heavy elements that could make a new planet some day
are in this little dot down in the centre. That's the actual new stuff.
Over tens of thousands of years, that shrapnel from the exploding supernova
gets mixed in with the gas between the stars,
and THAT becomes the stuff which contracts under gravity
to become new stars, new solar systems, new planets.
When you pick up a rock, you have a piece of the universe
that was formed five or seven billion years ago.
The silicon that makes up these bits of quartz were manufactured inside massive stars
and blasted into the gas between the stars.
But it's not just the rock - it's everything that you see in the Earth.
In this countryside of Arizona you can see the beautiful mountains
which are all formed out of elements that were manufactured a long time ago
from generations of stars that blew up five or seven billion years ago.
Over hundreds of thousands of years, countless supernovas spread and mingle.
This is what they become:
immense clouds made from ancient hydrogen gas
mixed with the remains of long-dead stars.
It's a stellar nursery, a place where new stars and new planets are born.
This is the Eagle Nebula - a vast cloud of debris,
the remains of an ancient explosion.
At its heart, new stars and worlds are being created.
These interstellar clouds are immense.
Each one of these bright dots is a star,
many of them much bigger than our own sun.
It was in a place like this that our solar system was born.
All the ingredients needed for the creation of everything are in here.
It just takes a little time for them to come together.
It's a dance that lasts millions of years.
It starts when the gas and dust form microscopic clumps
and it ends with new worlds.
(WALTZ MUSIC: ''THE BLUE DANUBE'')
As the clumps get bigger, they start to stick together, too.
They form clumps of clumps, always bigger, always heavier,
all swirling around each other.
And at the centre of them all...
..a vast cloud of gas and dust takes shape.
A whirling ball of matter, sucking in everything.
It grows bigger and bigger, hotter and hotter until...
..a new generation of stars is born.
And this one is OUR sun.
The remaining gas and dust is blown away, leaving behind the planets.
They keep growing. Smaller lumps of rock fall onto them for millions more years.
And when it's over, a new world is revealed.
Our world, the Earth.
But if that's how the Earth got here, then how did WE get here?
Eventually, water and an atmosphere came. But there was one thing missing: life.
Life could have started in the sea, or even in rock pools. But there is another possibility.
Life could well have started in a far-flung region of the universe
and hitched a ride here on the back of a comet.
(SWOOSH)
It may be the most intriguing theory of them all.
Some scientists think life on Earth appeared so quickly
that maybe it came from somewhere else.
Comets may hold the answer. Huge chunks of ice, kilometres across.
If very simple lifeforms could survive inside them,
life could have spread throughout the universe.
(THUNDER AND MUSIC FROM ''CARMINA BURANA'')
If the theory is right, you're about to watch the moment when life on Earth began.
Hurtling through space, the comet heads towards Earth.
Conditions are perfect: rich seas and atmosphere.
(''CARMINA BURANA'')
All that's needed is the spark.
Crashing into Earth, our alien ancestors are thrown in every direction,
scattering across the globe.
And our once lifeless planet is transformed forever.
Everything that makes up our world and us
came from the stars thousands of millions of years ago.
So next time someone asks you where you came from, tell them this.
You came from outer space, created in the heart of a star.