The Final Frontier? A Horizon Guide to the Universe

Ever since the first humans stood in awe and wonder

beneath the night sky, we have wanted to know what's out there

and what is our place in the cosmos.

For thousands of years, it seemed only religion could provide answers.

But today, it's science that guides our understanding of the universe.

The goal is to understand the universe in which we live.

We want to know why things are the way they are,

how they work, what everything is. We want to understand.

Was there a beginning? Did time continue before the Big Bang?

This is the deepest problem in cosmology.

Over the last 50 years, Horizon and the BBC have been

following science's pursuit of the biggest questions humanity can ask.

Where did the universe come from? How did we get here?

Are we alone?

This is the story of our final frontier -

the search for a complete understanding of the universe.

JFK: Man in his quest for knowledge and progress

is determined and cannot be deterred.

The exploration of space will go ahead.

We choose to go to the moon.

We choose to go to the moon in this decade and do the other things,

not because they are easy, but because they are hard.

When President John F Kennedy made that speech in 1962,

it was at the moment when human

exploration of space changed from science fiction into reality.

Hello, Apollo 11. Houston. We'd like you press on to star 44. Over.

Up until this point, the idea of leaving our planet,

and travelling into the cosmos seemed fantastical.

But within a decade, men had stood on the surface of the moon.

One small step for man...

It was a technological triumph...

..and perhaps the greatest voyage of discovery that we humans

have ever undertaken.

For thousands of years, explorers have set sail to discover new lands

and find what lies beyond the horizon.

But now, the nature of exploration is changing.

Today, we've mapped, we've catalogued, we've photographed

virtually every corner of the globe. We've even gone into space.

The human desire to explore is as strong as it has ever been.

The difference is, today, we don't need to physically

set sail into the unknown to learn new things.

Most of what we understand about the universe didn't come from our

space missions. Instead, it came from our clever instruments,

the great minds and extraordinary imaginations

of the people right here on Earth.

Back in the 17th century, one of the greatest breakthroughs in

the history of science was made in this apple orchard in Lincolnshire.

It would reveal the fundamental force that

keeps our feet on the ground and binds the entire universe together.

The idea sprung from the imagination of Britain's best-known scientist.

No, it wasn't Brian Cox, it was Isaac Newton.

The story goes that it was in this orchard that Newton was sat

thinking about the universe and an apple fell on Newton's head

and got him thinking about what it is that makes the apple fall.

What force pulls the apple towards the ground?

Newton suggested that the apple falls because of a force of attraction

that naturally exists between the apple and the Earth.

It's this force that we know as gravity.

But Newton's real genius was not to just stop with the apple,

but to ask the question, "Is the same force that causes the apple

"to fall here on Earth also responsible for the movement

"of much bigger things out there in the cosmos?"

Newton believed that gravity is a force that acts throughout

the entire universe.

In 1686, he finally managed to break it down into one single

mathematical equation.

Newton's understanding of gravity is actually incredibly simple -

the force between two objects depends on only two things:

the mass of the objects and the distance they are apart.

So the more massive the objects, the stronger the force, and the further

the objects are apart, the weaker the force.

With one beautiful bit of maths, Newton had figured out gravity.

But not just here on Earth.

The Moon seemed to orbit the Earth exactly as he predicted...

..as did the planets orbiting around the Sun.

Newton believed we live in a universe in which, ultimately,

the movement of everything can be predicted.

Newton's Law of Gravity was a huge leap forward

in our understanding of the universe.

It told us why the sun moves across the sky and why the Moon waxes

and wanes each month.

Gravity locks the Moon into orbit around the Earth, and the Earth and

all the planets into orbit around the sun. They move like clockwork.

And those movements can be predicted with such astonishing accuracy

that, three centuries after the falling apple,

we were able to use Newton's equations to launch

a rocket from Earth and land it safely on the Moon.

Figuring out one of fundamental laws of the universe from an orchard

in Lincolnshire was a pretty impressive bit of thinking. In fact,

nothing quite that extraordinary was to come along for another 300 years.

But when it did, it was mind blowing.

For Albert Einstein,

Newton's brilliant description of gravity wasn't quite enough.

Einstein wanted to know what caused gravity in the first place.

And in one gigantic leap of imagination,

he managed to come up with the answer.

Einstein called his theory General Relativity,

but the concepts were so bizarre, scientists ever since

have needed just as much imagination to explain them.

The Theory of Relativity is infamous for its difficulty.

I want to show that there's nothing peculiarly difficult about it.

Here's a little piece of the universe

and each of these stars represents a galaxy.

If I just stretch the rubber band...

Let me illustrate this with an example here.

Let's imagine this piece of jelly is the space.

Then the presence of matter is to distort the space.

The sun or the Earth bends space-time.

In bent space-time, you don't move in a straight line any more.

According to Einstein, space isn't simply an empty void.

It's more like a fabric woven from both space and time.

Objects like stars bend the space time around them.

Certainly, Einstein's Theory of Relativity

does lead us down some very strange and unfamiliar paths.

Any object that passes through that warped space-time will move

as if being pulled by a force

and that's what we experience as gravity.

Relativity is perfectly intelligible to anybody who is willing to think.

General relativity is probably one of the greatest feats

of human thinking ever accomplished.

And bizarre as the theory may sound,

experimental evidence has proved that Einstein was right.

Gravity really is a distortion of space and time.

BANJO MUSIC

Armed with Newton's gravity

and Einstein's Theory of Relativity, scientists could predict

and explain the movements of everything in the cosmos,

from an apple falling to the ground to the orbits of the planets

and the stars.

Einstein and Newton completely revolutionised our understanding

of the universe and they revealed much of the inner workings

of the cosmos using almost entirely the power of abstract thought.

Now, great minds like those don't come along very often

and, luckily, they don't need to,

because human beings have another great skill that's just as useful

when it comes to unravelling the secrets of the universe.

We're very good at building things.

In the early 1900s, astronomers set out

to build the most powerful telescope the world had ever seen.

A 4,000 kilogram slab of glass was ground and polished for five years,

to produce a gigantic mirror that was installed into the brand-new

Hooker telescope, here the Mount Wilson Observatory in California.

The mighty telescope could see, not just the stars in our own sky,

but the stars in other galaxies,

trillions and trillions of miles away.

And it was these distant galaxies that would lead astronomer

Edwin Hubble to discover the origin of the universe itself.

Up until this point,

people had thought that the universe was eternal and unchanging.

After all, the stars had been twinkling away in the night sky

ever since anyone could remember.

But with the new, super-powerful Hooker telescope,

Hubble saw something remarkable...

The universe was on the move.

The distant galaxies were hurtling through space.

And Hubble could even work out which direction they were moving in,

thanks to a handy bit of physics, known as the Doppler Shift.

STEAM ENGINE WHISTLES

In 1978, Horizon enlisted the help of a steam train, and no fewer than

six professional trumpeters, to show us how the Doppler Shift works.

This baroque experiment was actually first tried by a Dutch physicist

in the flatlands of Holland - steam engine, uniformed bandsmen and all.

Yes. Half a semitone?

-Do you think?

-Yes.

-What speed do you think he was doing?

I think about 40 kilometres.

The expert trumpeters on the train

certainly held their pitch constant, at a middle C,

but listeners on the ground heard the tone change

as the locomotive puffed by.

It was the physicist Christian Doppler, of Prague, who first

pointed out, 150 years ago, that such a change of pitch would be expected

whenever a steady source of waves moved with respect to an observer.

Today, we call it the Doppler Shift.

Approaching - higher pitch, shorter waves.

Receding - lower pitch, longer waves.

By listening for changes in the pitch of the note, it's possible to

work out if the source of the sound is moving towards or away from you.

And the same principle applies to light.

Using the powerful Hooker telescope,

Hubble measured the wavelengths of light coming from distant galaxies.

He discovered they were all hurtling away from each other

and that could only mean one thing - the universe is expanding.

If the universe is expanding, that means yesterday, it must have

been smaller and the day before that, smaller still.

And if you keep winding the clock back, it gets smaller

and smaller and smaller until, at some point, the whole thing

must have been all squashed together in a single tiny space.

Hubble had discovered that, far from being eternal and unchanging,

the universe had a beginning.

Scientists called it The Big Bang -

a single moment of creation, in which everything in the universe

burst into existence.

From a hilltop in Los Angeles, Hubble had discovered

the origin of the universe.

But he knew he could go one step further than that,

because if he could work out the speed at which the galaxies

were moving, he would know how long the cosmos had taken to grow

to its present size.

He could calculate the age of the universe.

But even with the most powerful telescope in the world at the time,

Hubble couldn't see distant galaxies in very much detail.

He could tell that they were moving,

but it was impossible to calculate their speed with any accuracy.

The problem was that no matter how sensitive the telescope,

the Earth's atmosphere distorts the light

coming from distant galaxies,

making it impossible to see them with any clarity.

In 1953, Edwin Hubble died without ever managing to calculate

the true age of the universe.

But 25 years later, a new building project began.

This time, astronomers set out to build a telescope that would be free

from the distorting effects of Earth's atmosphere.

Because this telescope would be launched into space.

It took 13 years, one and half billion dollars,

and a mirror so perfectly curved it could capture

light from distant galaxies in pin-sharp detail.

Its mission was to discover the age of the universe.

It was named the Hubble Space Telescope in honour

of Edwin Hubble's groundbreaking work.

But it very nearly tarnished the reputation of the whole of science.

And lift off!

The space shuttle Discovery with the Hubble Space Telescope.

A window on the universe.

There are smiles galore down here.

It's quite a sight.

Great work up there, you guys.

The moment everyone was waiting for had arrived.

Hubble was ready to transmit its first pictures back to Earth.

But something was wrong.

What we had expected to see in those first images

were very, very sharp points of light.

What we actually saw were kind of big blurry things.

In fact things that at first glance didn't look a lot sharper

than what we could see from the ground.

And we looked at them and we thought, "Hmm."

The Hubble had a serious problem.

The most perfect mirror in the world...

was the wrong shape.

It was slightly too flat,

which meant that the light reflected from its edge,

and light from its centre, were focused in different places.

It could not produce a sharp image.

And there was nothing anyone could do about it.

Remarkably the original equipment used to test the mirror was

still in position.

And it was here they discovered that unknown

to anybody one tiny accident had crippled the telescope.

A fleck of black paint just two millimetres wide

had at some stage been

chipped off the cap of one of the measuring rods that had been

used to test the mirror's shape.

This exposed a chink of metal.

Light hitting this chink distorted the measurements,

causing the fatal error.

The mirror was only minutely misshapen -

just a 50th of a width of a human hair.

But it was enough to put the mission's goals out of reach.

The Hubble had to be saved at all costs.

Which we listed as mechanical correction or deformation.

We put everything on the table,

even the craziest idea to see what we could do to fix the problem.

This is replacement of the secondary,

just as a straight correction.

And they range from going

up in the shuttle taking the space craft,

bringing it back to Earth and replacing the primary mirror.

To send astronauts up and actually inside the tube

of the telescope to do something to the optics.

Among the proposals was the ingenious solution.

An instrument that would match the error in the mirror in reverse

and cancel it out.

Plans for an ambitious repair mission began to take shape.

The astronaut team undertook the most punishing training

schedule since Apollo to make ready for this boldest of missions.

Five, four, three, two, one...

..and we have lift off!

Lift off of the space shuttle Endeavour on an ambitious

mission to service the Hubble Space Telescope.

In December 1993 the impossible mission was launched.

Hello, Houston, we are ready. Let's go fix this thing.

The astronauts got to work.

They knew that the tiniest mistake

could be catastrophic for the mission.

First came the delicate task of putting in the new camera.

It goes in with incredible precision.

What we were worried about was

any astronaut could just kind of bump into it,

and that would be the end of our mission.

The astronauts eased the new camera into place.

My side looks good.

That's beautiful. Looks like it's in there.

Two weeks later, it was time to put the repairs to the test.

CHEERING

-Right there!

-Ooh!

-Wait, wait, wait.

-Yeah. Yeah.

Those are actually stars!

Orbiting 350 miles above our planet,

the telescope could see distant galaxies in breathtaking clarity,

and measure the speed at which they were moving

with unprecedented accuracy.

The Hubble Space Telescope was finally able to finish

the work that Edwin Hubble had started.

It could measure the age of the universe.

The answer was 13.7 billion years.

The Hubble Space Telescope went on to produce the most

magnificent images of the universe the world had ever seen.

They showed that space isn't just an endless blanket of stars -

it's populated by a bewildering variety of celestial phenomenon.

There are colossal furnaces where new stars are forged.

And violent explosions where others have died.

There are ancient, primordial galaxies in the furthest reaches

of space, and newer ones stretching out in majestic, glittering spirals.

Hubble would have been proud.

The construction and launch of the Hubble Space telescope was

one of the most ambitious engineering projects ever attempted.

But if it wasn't for the skill

and the determination of the engineers,

then it could have become one of science's greatest failures.

It's that persistence and determination to overcome problems

that has driven our quest to understand the universe.

And nowhere have we needed it more than to find the answer

to perhaps our most profound question - are we alone?

Science fiction fans aren't the only ones

who believe in extraterrestrials.

Hello!

Is there anyone out there?

Plenty of scientists believe in them too.

In fact, science's determination to find alien life

borders on obsession.

They've scoured the skies, sent messages out into space

and spent years listening intently for the faintest sign of ET.

So far, they've found nothing.

But there is one place they have been searching more than any other.

Generations of scientists have dreamed of finding life there.

It's our nearest planetary neighbour - Mars.

Something is happening to the children of Mars.

As leader of the Martians you must do something about it.

I know. But what?

In the late 19th century, American astronomer Percival Lowell was

so convinced that life existed on Mars,

he thought the markings he could see

through his telescope must be canals,

built by a Martian civilisation.

Up until the 1970s, it was thought that dark patches

on the surface of the red planet could be extraterrestrial forests.

We've just had some amazing photographs sent back

by the American probe to Mars - Mariner 6.

Just look at that!

You can see some of the dark areas, which may be vegetation...

Of course, those early observations were just tricks of the eye.

But the hope of finding Martians never faded.

And in 1996,

the first strong evidence of life on Mars was announced.

If this discovery is confirmed, it will surely be one of the most

stunning insights into our universe that science has ever uncovered.

Researchers working in Antarctica had found a meteorite

lying in the snow.

A battery of tests showed that this was no ordinary meteorite -

it had come from Mars.

Closer analysis revealed something extraordinary.

The Martian rock contained large quantities of organic carbonates...

..a compound that is usually associated with living things.

This is just going to knock

the socks off of people when they see this.

Samples were sent to NASA, where astrobiologist Everett Gibson

set out to establish

if this meteorite contained evidence of alien life.

Everett Gibson took the meteorite to the head of NASA's electron

microscope lab, Dave McKay.

As we zoom in on this cave area here,

we see some interesting features.

One evening, after David had spent many long hours on the microscope,

we were moving around and we came across a region

that appeared to be a little different

to what we had normally seen.

And we kept scanning in and scanning in at higher magnification,

and we saw something that caught our eye.

And we said, "What is that?"

We found this structure. It had 10-12 segments in it,

and appeared to have a head, and appeared to have a tail.

And we looked at each other

and kind of looked with this look that said, "This can't be."

And the significance of the structure got to both of us.

That night I had difficulty sleeping.

I was saying, "Could we have a microfossil here from Mars?"

Later this month, scientists are

expected to announce remarkable new findings about life on Mars.

We are right on the edge of a potential unbelievable discovery

that's going to rock our world if it's true.

Sure enough, the press had a field day.

They are the remains of Martian life.

But there's a problem.

Some microbiologists think that what NASA are seeing are might not

be bugs but blobs -

artefacts created

when the sample is coated with gold for use in the electron microscope.

Is the fact that things

are consistent with the presence of life

enough to convince you

that you're making one of the most sensational claims ever made.

And I would say no.

What you need is evidence that requires life to explain it.

Nealson's team have been looking at rocks with a new

kind of electron microscope.

This one can work without the gold coating.

To my way of thinking, it's very impressive how different

the samples are when they're coated with gold or not coated.

His uncoated rocks look jagged and crystalline

at high magnification.

But add the gold coating and tiny blobs appear,

which are about the same size as the famous Martian worm.

The edges now can be rounded off with the gold

and even an expert could be fooled.

You look at it and you say, "Wow, that could be life."

So this might just be rock fragments,

made to look like a worm by a thin coating of gold.

Almost 20 years later, the controversy still goes on.

So far, we've found no signs of intelligent life on Mars

and no hard evidence of microbes either.

But all hope is not lost.

Even if Mars is barren and lifeless today,

it might still have been a home to life in the past.

Because for a planet to support life,

there is one vital ingredient it must have.

One special substance that it's thought any alien,

anywhere will need...

..water.

Life involves complex chemical reactions -

and as far as we know, complex chemistry needs liquid water.

On Earth, wherever there is water, there is life.

So if Mars once had liquid water,

then it dramatically increases the chance that it once had life too.

An armada of spacecraft

and six robotic rovers have been sent probe the red planet.

They've found no sign of water on the surface today.

But there is plenty of evidence that things were different in the past.

Did a river once flow through this valley?

Was this once a lake?

Perhaps, billions of years ago, Mars had oceans, clouds and rain,

just like the Earth.

It's an intoxicating thought.

Last year, NASA sent one more rover - Curiosity -

to the surface of the red planet.

It's the most sophisticated ever built.

Just a few weeks ago, it landed.

Its mission is to discover once and for all

if Mars ever had the conditions to support life.

Here's hoping.

Finding any kind of life on Mars,

even if it's the fossilised remains of tiny bacteria,

would mean that the Earth is not unique in that respect.

But the real goal it to try and find complex intelligent life.

Now we're probably not going to find it within our solar system,

but there's a lot of other solar systems out there,

and perhaps orbiting another star in another part of the galaxy

is a planet just like Earth.

The problem that we've got is finding it.

With 200 billion stars in our own galaxy alone, astronomers had

suspected for centuries that there must be other planets out there.

But they'd never managed to see one.

I have little doubt that at this very moment,

on some alien far-off planet.

There's a broadcaster

addressing an audience saying exactly what I am saying to you.

And on his TV screen he maybe showing a star field.

But suppose we could

look at that scene from a planet going around the nearest star.

The overall view would be the same,

but there would be an extra point of light representing our own sun.

And if the sun appears only as a point, what chance

would our hypothetical astronomer have of seeing the Earth?

Obviously none at all.

In fact, from the Earth we similarly cannot see the planets of

other stars. We can only infer that they exist.

But I'm quite sure that they do.

Spotting a planet in orbit around a distant star is like trying

to spot a grain of sand in the glare of a floodlight,

from a hundred miles away.

So not surprisingly, astronomers struggled to find any

planets at all, let alone one that looked like ours.

The search for another Earth was stuck in the starting blocks.

But, in the 1950s, a Russian astronomer named Otto Struve

had come up with an ingenious idea.

He suggested a way to spot planets by looking at stars.

Gravity holds planets in orbit around their stars.

The star pulls on the planet, but the planet also pulls

back on the star, making the star move with the tiniest of wobbles.

Struve argued that this wobble should be

detectable from here on Earth.

The trouble was telescopes at the time weren't capable of making

accurate enough measurements.

Astronomers would have to wait

another 40 years for technology to improve.

The first planet beyond our solar system was finally discovered

in 1992, and it opened the floodgates.

Within a decade, almost a hundred more had been found.

Otto Struve's technique was brilliant.

But it had one major flaw.

It's much easier to spot a big wobble than a small one.

The closer the planet is to the star, the bigger the wobble -

but the hotter the planet will be.

Every single one of the planets that had been found were searing hot,

tortured worlds...

with no chance of life.

To find a planet like the Earth, orbiting at a safe distance

from its star, astronomers needed to detect much smaller wobbles.

With ordinary telescopes, that was impossible.

But then, in 2003,

a brand new planet hunting instrument was unveiled.

Horizon was there to tell the story.

Between the Andes mountains and the Pacific Ocean,

on the remote southern edge of the Atacama Desert lies

one of the most extraordinary observatories on Earth.

The high elevation and the low rainfall,

just one millimetre a year, makes it

the perfect place for uninterrupted views of the southern night sky.

Please come in. I have something to show you in here.

Professor Stephane Udry is the proud owner of a machine which

could change the course of human history.

Inside this big box is an enclosure

and inside this is a vacuum tank, with the instrument that is

the most sensitive in the world now for planet detection.

With this instrument we can detect low mass planet five,

ten times the mass of the Earth.

Can we go in?

No. Of course not, because just opening the door will destroy

the measurement for a few days.

Because we need to have a very stable instrument to be able

to repeat the measurement with the same precision day after day,

month after month, years after years.

And that's exactly what they've been doing.

They drew up a list of a thousand targets

taken from the Gliese Catalogue of Nearby Stars...

and began measuring and re-measuring each candidate,

hunting for wobbles that had previously been too small to detect.

But one star caught Stephane's attention.

Gliese 581 was in our target list since the beginning.

Categorised as Gliese 581a,

it's a Red Dwarf star, a third of the mass of our own sun.

When the wobble was plotted it revealed 581b,

a massive planet the size of Neptune, close into the star,

and orbiting once every five and a half days.

It was no Earth,

but the star's wobble held some fine

detail that still intrigued Stephane.

We noticed that there was something else in the system.

There seemed to be another, smaller planet lurking in the detail.

That something else could be a five Earth-mass planet very close

to the star.

If Stephane's hunch was right,

it would be the smallest planet ever detected around a distant sun.

And this planet seemed to be habitable.

We got excited because the distance was just right for the planet

to possibly be in the habitable zone.

After years of hunting, the search for Second Earth was over.

European astronomers have spotted a new planet outside our solar

system which closely resembles the planet Earth.

The probability that there is life elsewhere in the universe

goes up a bit.

This latest find has set the world of astronomy alight.

It is always very exciting to be the first one to know.

It's like being in the spaceship

coming to a planet and being the first one to see the landscape.

So far, astronomers have searched just a tiny

fraction of the stars in our galaxy,

but they've already found five more potentially habitable worlds.

That's five more chances that out there somewhere there is

another Earth.

And for every new world that astronomers discover,

the dream of finding intelligent life gets a little closer.

Science has completely transformed our understanding

of the universe and most of those breakthroughs have been made

right here on Earth.

They've allowed us to explore alien worlds,

to unlock the secrets of gravity,

to discover the very origins of the universe itself.

But it seems the deeper we look, the more questions we find

and the more profound they become -

questions that we've been asking for thousands of years,

such as, "Where did we come from?"

In the beginning there was nothing -

no galaxies, no stars, not even atoms.

Then 13.7 billion years ago, from nothing came everything.

The universe burst into existence.

We all came from the Big Bang.

But how did it happen?

How did the Big Bang actually create the atoms that make

up our bodies, and the bodies of the planets and the stars?

One inescapable fact is that we exist,

so does the sun, the stars, the Earth and everything else.

And no-one has yet explained how the matter

came into existence in the first place, which adds force

to my own contention that we are strong on the detail

and weak on the fundamentals.

Up until the 20th century,

it was thought that the atom was the smallest particle in existence.

Now we know that inside the atom live a whole host of particles

that are even smaller still.

The protons, neutrons and electrons. These particles

are the building blocks from which everything in the universe is made.

And somehow, they were forged from pure energy in the Big Bang.

But how did that actually happen?

How did energy become matter that we can touch?

The answer could lie in a mysterious, invisible field.

The best theory we have at the moment for the origin of mass

for what makes stuff stuff is called the Higgs mechanism.

And the Higgs mechanism works by filling the universe with...

with a thing. It's almost like treacle.

And by the universe,

I don't just mean the void between the stars and the planets,

I mean the room in front of you.

Some particles move through the Higgs field

and talk to the Higgs field and slow down,

and they're the heavy particles. So all the particles that make

up your body are heavy because they're talking to the Higgs field.

Some other particles, like particles of light, photons,

don't talk to the Higgs at all and move through at the speed of light.

To prove that this strange, treacly field is real,

scientists need to find the particle associated with it.

They call it the Higgs particle.

The problem is that this

particular particle isn't exactly easy to find.

If it exists at all, it's only for a fleeting moment.

And the only way to see it is to travel 13.7 billion years back

in time to moment it first flashed into existence - in the Big Bang.

Needless to say, that's a bit tricky.

But rather than give up,

scientists came up with an extraordinary solution.

They would conjure up the particle themselves,

by recreating the conditions of the Big Bang here on Earth.

They needed a burst of energy so powerful,

it would mimic the moment of creation itself.

And the best way to achieve that is to smash things

together at phenomenal speeds.

So they chose the tiny proton from the heart of the atom and set out

to build the biggest proton smashing machine the world had ever seen.

13.7 billion years after it all began...

..we're about to go back to the beginning of time...

..with the largest and most complex

scientific experiment ever attempted.

The Large Hadron Collider or LHC has just one simple

but audacious aim - to recreate the conditions of the Big Bang...

..in an attempt to answer the most

profound questions about our universe.

The goal of particle physics is to understand

the universe in which we live.

We want to understand why things are the way they are.

How they work. What everything is. We want to understand.

The large Hadron Collider spans the Swiss French border just

outside Geneva.

It's the largest particle accelerator ever constructed.

It's down here in caverns brimming with the latest

technology that the big bangs will be made.

The bits of matter we're going to

fire around the LHC are called protons.

Not one, but four colossal particle detectors have been installed

around the ring to take pictures of what happens when protons collide.

Our theories predict that the Higgs particle is immensely heavy.

And it's a general rule in particle physics

that heavy particles are unstable.

They simply fall apart into lighter particles.

So if the Higgs is a real part of nature -

it would have long ago vanished from the early universe.

And today, even if we manage to recreate the Higgs,

it'll disappear...

..before we can see it.

This is a simulation of a single proton-proton collision at the LHC.

It's actually a simulation of the production of a Higgs particle.

Now the Higgs particle you don't see of course,

it just decays in a fraction of a second.

But what you do see is the smoking gun.

In this case, two very clear red tracks -

these two particles here called muons that have gone straight to

the very edges of the detector.

And if we see not just one collision like this but maybe ten.

maybe a hundred, then we'll have discovered the Higgs and for

the first time we'll understand the origin of mass in the universe.

That is, if the experiment works.

On the 10th September 2008 the LHC was switched on and the first

particles were smashed together at close to the speed of light.

And in July 2012 the first glimpse of the Higgs particle was announced.

Scientists hunting for the elusive Higgs boson

say they've discovered strong signals that it exists...

Say they've uncovered signs of the elusive Higgs boson,

known as the God particle...

Researchers presented results from two independent experiments...

Evidence which helps them

move closer to the building blocks of the universe.

The results show that the mysterious Higgs field really exists,

which means we now better understand how the matter that makes up

the universe was formed, and why it is the way it is.

You might think that staring into the face of creation would

mark an end to science's quest to understand the universe,

in fact it could just be the beginning.

Once you understand how the Big Bang created us and created everything

in the universe, you realise there's a much bigger even more profound

question beyond it - and finding an answer to that will require

more imagination, more intelligence, more determination than ever before.

If the Big Bang created the universe -

then what created the Big Bang?

That question reveals a major problem with

the idea of the Big Bang.

It exposes the one part of the theory

that just doesn't make any sense.

How did everything apparently spring, unbidden, from nothing?

The idea of "everything from nothing" is something that

has occupied physicist Michio Kaku for much of his professional life.

You know, the idea sounds impossible.

preposterous. I mean, think about it, everything from nothing!

The galaxies, the stars in the heavens coming from a pinpoint.

I mean, how can it be?

But you know, if you think about it a while,

it all depends on how you define nothing.

This is the biggest vacuum chamber in the world.

It is here that NASA recreates the conditions of space on Earth.

Its eight-feet-thick walls

are made from 2,000 tonnes of solid aluminium.

It takes two days of pumping out the air, and another week of

freezing out the remaining molecules to create a near-perfect vacuum.

A cathedral-sized volume of nothing.

When they switch this place on,

this is as close as we can get to a state of nothingness.

Everywhere we look we see something.

We see atoms, we see trees, we see forests, we see water.

But hey, right here, we can pump all the atoms out,

and this is probably the arena out of which genesis took place.

Except, of course, it isn't quite that straightforward.

For a start, the nothing created by NASA still has dimensions.

This is nothing in 3-D.

And the tests carried out within the chamber can, of course, be viewed.

This is nothing through which light can travel.

NASA's nothing has properties.

This nothing is, in fact, something.

So, for me, the universe did not come from absolute nothing,

that is a state of no equations, no space, no time,

it came from a pre-existing state, also a state of nothing

that our universe did in fact come from this infinitesimal tiny

explosion that took place, giving us the Big Bang and giving us

the galaxies and stars we have today.

For Professor Michio Kaku,

the laws of physics did not arrive with the Big Bang.

The appearance of matter did not start the clock of time.

His interpretation of nothing tells him that there

was, in short, a before.

Most scientists now believe that there must have been

something before the Big Bang.

And understanding what that something was and how it

worked is the new frontier in our quest to understand the universe.

It occupies the minds of some of the greatest thinkers on the planet.

And the solutions they've come up with

stretch human imagination to its limits.

You have Swiss cheese, OK?

Just imagine that the cheesy part of it is heavy vacuum

and the universe expands and these bubbles appear inside.

The universe is born inside of a black hole.

-String theory.

-M-theory.

Where M stands for magic, mystery or membrane.

It's actually safe to create a universe in your basement.

The Big Bang is the aftermath of some encounter

between two parallel worlds.

These theories sound pretty far-fetched.

But then we are dealing with concepts

that are almost beyond imagination.

At the moment, they're fighting it out with no clear winner.

So nobody can say for sure what caused the Big Bang.

For the time being, this is as far as we can go.

Science's quest to understand the universe is one of the greatest

voyages of discovery that we've ever embarked on.

But any explorer worth his salt will tell you that for every

door that you open, another one lies beyond. Science has revealed

a universe that is more beautiful, more extraordinary, than we ever

could have imagined,

but that journey for us is only just beginning.

Subtitles by Red Bee Media Ltd