What Happened Before the Big Bang? Horizon

In the first few years of the new millennium,

this starkly strange building

emerged from the Canadian countryside.

In it are housed some of the most extreme minds in science.

The ideas produced within the walls of this institution,

are intended to shed new light on science's hardest problem.

Is there an ultimate answer?

I don't know.

I don't even know if the question makes sense.

They intend to tell us once and for all where we came from

by unravelling the deepest mysteries of the birth of the universe.

Time did not exist before the beginning.

Somehow, time sprang into existence.

Now, that's a notion which we have no grasp of

and which may be a logical contradiction.

They are re-writing science's story of creation.

Why is it, all of a sudden, there are

laws of nature, and where did they come from?

Why these laws and not other laws?

And they've concluded that one of the 20th century's

greatest scientific ideas might have to be thrown out.

There is certainly not big bang. That is impossible.

I don't believe in that at all.

For thousands of years, science has tied to understand the mysteries of the night sky.

It is an awe-inspiring achievement that a certain kind of ape

has discovered that it is living on a planet,

that the planet is flying around a star in a galaxy.

..and that that galaxy that is just one of a vast sea of galaxies in a near-infinite universe.

But now it seems, science is about to go one step further

with an idea that will make previous breakthroughs in cosmology

pale into insignificance.

It is the grandest concept imaginable,

yet it has its roots in an notion that we are all familiar with.

Cause.

and effect.

Cause.

Effect.

It's a simple, yet powerful idea.

Because one thing follows another, we can stray from the present.

We can boldly stride into the future,

and confidently travel back in time.

It's this idea that allowed American astronomer Edwin Hubble to draw

a far-reaching conclusion to what he saw in the movement of galaxies.

The discovery of the century had to be Edwin Hubble making his Hubble diagram.

And what he did is he just plotted distance versus velocity, or speed, of the galaxy.

And can you imagine one day making that plot

and you discovered things further away

were moving faster away from you?

And this is the famous Hubble diagram

which told us that the universe is expanding.

This revolutionised our view of the universe.

Not only was there a universe out there but now there was a universe

that was expanding and it was getting bigger and bigger with time.

And it didn't take long for someone to figure out,

"If it's getting bigger with time, surely it started from somewhere."

And this really brought out the first idea

that there was a moment of creation

i.e. the big bang.

I think the discovery that the universe was expanding

was one of the most significant in science.

It's on a similar level to Darwin's discovery of evolution.

It tells us the universe

wasn't always the way it is today,

it tells us we came from something,

something violent,

something extraordinary.

The big bang is an elegant answer to the biggest question that science can ever ask.

It's startling idea.

It gives us a sense of origin.

And however odd the notion sounds, it's a comfort to know exactly where we came from.

Science assures us that our universe exploded into existence

13.7 billion years ago.

And thanks to cause and effect, science knows what happened

right from the very beginning of the bang itself.

Well, almost.

So, in the standard picture, if this is the history of our universe,

then this is where the big bang is.

At t = 0.

This is when the baby was born.

And when the universe is somewhere here.

where this is 10 to the power of -34th of this one second.

So we know about the universe up until 0.0000341 seconds

before it started.

That's a pretty small number, isn't it?

At this point, the classical theory would fail.

The thing is, big bang doesn't quite work.

So much so, that people are now starting to think the unthinkable -

that big bang wasn't the beginning at all.

How many people think that there was something before the big bang?

Ten years ago, this would never have happened.

Then, there was no doubt that "before the big bang"

made no sense. But today, the certainty has gone.

There is no escaping the inconvenient truth

that Hubble's graph,

work of genius though it is,

contains a huge problem.

It tells us that everything we see in the universe today -

us, trees, galaxies,

zebras, emerged in an instant from nothing.

And that's a problem.

It's all effect, and no cause.

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 galaxy,

the stars in the heavens coming from a pinpoint.

I mean how can it be? How can it be that everything comes from nothing?

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

it all depends on how you define "nothing".

In Sandusky, Ohio, is Plum Brook Station.

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

and part of that means generating nothing.

..in vast quantities.

This is the biggest vacuum chamber in the world.

Its eight-feet-thick walls are made from 2,000 tons 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.

So if you really understand the state of nothing,

you understand everything about the origin of the universe.

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.

I think there are two kinds of nothing.

First there is what I call absolute nothing, No equations, no space,

no time, absence of anything that the human mind can conceive of,

just "nothing", but then I think,

"There is the vacuum, which is nothing but the absence of matter."

Professor Kaku's version of nothing is a perfect vacuum where,

on the face of it, there is only energy.

But in a perfect vacuum,

energy sometimes transforms itself,

temporarily and briefly, into matter.

It is one of these tiny explosions

that might have kept going and ended up in the big bang.

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 actually 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".

If he's right, there's an opportunity for a cause to have an effect after all.

At Stanford University near San Francisco, Professor Andrei Lind

believes that the big bang itself is a flawed concept,

but one that holds tantalising clues to the "real" story of creation.

The idea of the big bang was a very powerful idea,

but, er, this idea chad its own problems.

One of the problems -

why the universe was as big as it is now?

The second idea - who made it expand?

What caused this explosion?

Big Bang was clearly a very special explosion.

Ordinary explosions are messy.

This one produced a universe that wasn't messy at all.

Our universe is "smooth" -

it looks more or less the same in every direction.

It was an observation that required a radical explanation.

Professor Linde was one of the cosmologists who provided it.

The idea was that, just after matter first appeared, rather than a messy explosion,

there was instead a massive and unprecedented growth in the size of the universe.

The process is called inflation.

If one assumed that there was

this period of exponential expansion of the universe,

in some energetic, vacuum-like state,

then you can explain why the universe is so large,

why our universe is so smooth at the very large scale,

why properties of the universe in different parts

are so similar to each other.

All of these questions can be addressed

if one uses inflation.

The big bang and inflation explained everything.

the universe began with a matter-producing explosion.

Then, inflation sped things up and smoothed things out for a while,

before disappearing, to leave the gently-expanding universe we see today.

Inflation was so successful

that Linde began to wonder if the big bang was needed at all.

Maybe it's easier to say that there was inflation from the very beginning.

It was not difficult from the point of view of mathematics,

it was a difficult psychological step

to give it up.

Linde's masterstroke was to cut the big bang

out of the story altogether,

and to envisage inflation as something from which our universe emerged.

A pre-existing condition that has been there...

well, forever.

You have Swiss cheese, OK?

And in Swiss cheese, we have these bubbles of air.

OK? So just imagine that the cheesy part of it

is heavy vacuum and the universe expands

and these bubbles appear inside.

And it looks like infinite universe inside.

So for Linde, the big bang isn't really a starting point at all

He thinks that it's simply the end of something else.

The universe appeared out of the cheese of what he calls "eternal inflation",

in an area where the inflation simply ran out of steam.

This has huge implications.

It means that when we look into the night sky,

we see only a tiny piece of the story of existence.

Our universe is not alone.

There are others,

all co-existing within the eternally-inflating super-universe of Linde's cheese.

And he's counted them.

We have calculated how many really different options

you can see on the way of your travel.

And what did that give you?

And that gave us the number 10 to the degree 10 to the degree

10 to the degree 7.

This is a huge...

absolutely enormous number.

But that's what we got as a result of our calculations.

Andrei Linde is a highly-respected scientist.

His ideas of the multiverse, odd as they seem, are now within the scientific mainstream.

For many cosmologists, eternal inflation is in itself a reasonable explanation

of what existed before our universe.

But for others,

it's utter nonsense.

It's too arbitrary.

You can start it one way,

another way, you can tweak the parameters

to get whatever observations you want.

This is very dissatisfying.

I basically feel we are letting down our tradition

of theoretical physics, which is the most precise,

predictive, powerful area of science we know,

and we've got to do better than this.

Professor Turok runs the Perimeter Institute for fundamental physics research near Toronto in Canada.

And you will get...one plus two!

It is full of men and women

trying hard to follow their leader's urgings to "do better".

Eternal inflation is quite a different creature than ordinary inflation.

Here, thinking about what happened before the big bang is all part of a day's work.

And though most people think there was something before the big bang...

How many people think there was

a universe before the big bang which was much like this one?

..no-one can quite agree on what,

or even if there was a bang at all.

I do believe that there is no big bang, but I don't know what is on the other side for sure.

How much would you bet? Would you bet your house?

-Would you bet, um...

-LAUGHTER

Param Singh is working on a theory that he hopes will shorten the odds.

He's trying to overcome the same problem as everyone else,

namely the rather inconvenient idea of everything emerging from nothing,

one Thursday afternoon 13.7 billion years ago.

But Param's ideas strike at the fundamental principles that cause all the problems in the first place.

So if you believe the universe is expanding

and if you look at its history,

then the universe must have expanded from something.

And if you look backward and backward,

what big-bang theory tells you

is that the universe starts expanding from nothing.

The principle mathematical objection is that, as the clock is wound back,

and Hubble's zero hour is approached,

all the stuff of the universe is crammed into a smaller and smaller space.

Eventually, that space will become infinitely small.

And in mathematics, invoking infinity is the same as giving up.

Or cheating.

Even if the mathematical laws would not have broken down at this point,

even then it's philosophically very incomplete,

like, how can something just originate from nothing?

And that is what the theory has to explain.

It's Param's job to understand how the unimaginably large emerged from the infinitesimally small.

But it's not just philosophy and infinity that stands in his way.

If you look at our universe which is at large scales, the mathematics that we know

from Einstein's' theory very well describes most of the phenomena -

all of the phenomena. Like this ball which I throw up - it comes back.

But if I want to describe what is inside this ball,

the atomic structure of the ball,

or how the molecules are made and how atoms are made,

what are their fundamental constituents,

then I don't use classical gravity, I use a completely different physics called quantum mechanics.

If I look at the universe, and I ask the question, I want to describe how it came from nothing,

what was its nature when it was very small,

then I have to use both the classical gravity and quantum mechanics and they don't talk to each other.

What I need is a new theory, a new mathematics.

And that is the biggest problem to find.

Param Singh has been working on a way to combine the two systems.

A scheme that works in the very big AND the very small.

What he's found is that the maths predicts a very peculiar phenomenon.

What we find is, that gravitational force,

which is attractive, becomes repulsive when the universe is very small.

That is predicted by the mathematics,

the new mathematics which we obtain by the marriage of quantum mechanics and Einstein's gravity.

It is a completely different paradigm now.

The problem of the big-bang infinities

are swept away by the new "repulsive" gravity.

The point of "everything in nothing"

is never reached.

The maths is here,

so this is one of the equations which took a couple of years to derive

and the part in orange

is the one that is predicted by Einstein's theory

and the part in the white

is the corrections which come from quantum gravity.

So if you look at this orange part,

this orange part tells you that if you look at the universe,

which is becoming smaller and smaller as you approach big bang,

the left-hand side and the right-hand side,

they both become infinity.

And we know that whenever we encounter infinity in mathematics,

something has gone terribly wrong.

So what quantum gravity gives us is this expression,

which ensures that as we approach the big bang,

when the universe is becoming smaller and smaller, both sides become zero,

and after that, the universe starts expanding again

on the other direction and the same laws remain valid.

-Problem solved.

-Problem solved.

In Param Singh's scheme, instead of emerging from nothing,

our universe owes its existence to a previous one

that had the misfortune to collapse in on itself,

then, thanks to some clever maths,

rebounded to become what we see today.

So the big bang was not a bang at all.

It was, rather, a big bounce.

It's a surprising thing, a bouncing universe, but in nature,

if you look around us, there are lots of cycles, always happening,

like we have seasons,

we have even the motion of planets around sun.

In fact, nature tries to prefer things were just cyclic in a way.

But if we look at the whole lifespan of the age of the universe,

which is billions of years, then maybe these cycles or the bounces, may not at all be surprising,

and these are just the cycles of weather,

in a way, for the universe,

of going through contraction and expansion

and contraction and expansion and so on.

Of course, it might all be nothing more than a fantasy world of maths and little else.

And there's always the nagging question

of what started the infinite bouncing in the first place.

Well, that's the most important question and I don't know the answer to that.

Maybe very soon we'll find an answer to how it all started.

-But it wasn't big bang?

-It was certainly not big bang,

that is impossible, I don't believe in that at all.

Down the corridor from Param Singh is the office of Lee Smolin.

But Professor Smolin rarely uses it.

He's more usually to be found doing his thinking elsewhere.

For him, the very idea of "everything from nothing" -

the so-called "singularity" - points to a lack of understanding.

I strongly, strongly believe

that there was a period before the big bang,

that the singularity was eliminated.

To me, the singularity is not an indication

that there was a first moment of time -

it's an indication

that general relativity is an incomplete theory.

It's general relativity shouting at us,

screaming at us, "I am not the end."

There is more to understand.

In his bid to further his own understanding of the cosmology,

Professor Smolin has cast his scientific net wide.

And, though he shares a lot of ground with Param Singh,

and even Andrei Linde,

his interpretation of what happened before the big bang

owes more to Charles Darwin than to Albert Einstein.

The idea works by analogy to how biology works.

It says that the universe has an ancestor,

which is another universe.

How is the universe born from the ancestor?

According to this hypothesis,

the universe is born inside of a black hole.

A black hole is a star which collapses,

where everything becomes infinite and time stops.

There is a bounce inside of every black hole.

The material contracts

and contracts and contracts again and then begins to expand again.

And that is the big bang which initiates a new region of the universe.

Smolin's natural selection idea proposes that for a universe to prosper, it must reproduce.

And for that to happen it must contain black holes,

that according to Smolin, spawn offspring universes.

Before the big bang was another universe much like our own.

In that universe there was a big cloud of gas and dust.

It collapsed to form a big massive star,

that star exploded, it left behind a black hole,

and in that black hole there was a region,

if you were misfortunate enough to fall in,

you would find it becoming denser and denser and denser.

You wouldn't survive this, but let's imagine you did.

And all of a sudden,

it would explode again and that would be our big bang.

It's a beguilingly simple, and controversial combination of two

of the greatest scientific breakthroughs of the modern age.

I think that the theoretical evidence is moving towards this idea.

And that's good.

That gives me some confidence for the future.

Professor Smolin is convinced that the big bang was not the beginning.

And until his theory of cosmological natural selection is conclusively proven, he's committed

to pursuing all avenues that might provide answers to what came before.

I think the only way to keep going in this business is to go

under the assumption that tomorrow's idea will be the best one so far.

So I'm trying!

Ten years ago, the only idea in cosmology was the unexplained big bang followed by inflation.

"Pre-big bang" was only talked about behind closed doors by radicals.

But today it's almost mainstream.

Yeah, we just have to replace this with this.

Back at the Perimeter Institute,

there are any number of strange ideas about how our universe was born.

And perhaps the strangest of all comes from the Institute's director, Professor Neil Turok.

There are essentially two possibilities at the beginning.

Either time did not exist before the beginning,

somehow time sprang into existence.

Now that's a notion which we have no grasp of

and which may be a logical contradiction.

The other possibility is that this event which initiated our universe

was a violent event in a pre-existing universe.

Professor Turok and his colleagues

have come up with a model that assumes a complex version of existence,

requiring ten spatial dimensions, plus time. Simple(!)

What is present in these models, the picture of the world in these models,

is that we live on an extended object called the brane.

And a brane, it's B-R-A-N-E, short for membrane.

But it's a membrane which is three-dimensional.

All of space that we live in is part of this brane.

And within these models you have to have at least two of these branes.

You can't have only one, there have to be at least two.

And they are separated by a little gap along a fourth dimension of space.

It's not one of our existing dimensions.

And basically within these models, these two branes can collide.

When they collide, they remain extended.

It's not all of space shrinking to a point.

They fill with a density of plasma and matter, but it's finite.

Everything is a definite number,

which you can calculate, and which you can then

describe using definite mathematical laws,

and so that's the essential picture of the big bang in our model.

And I think it's becoming a real alternative to the conventional picture

that everything was created at the big bang.

For many cosmologists, this is mathematical sleight of hand,

and an unwelcome distraction to the serious business of improving on the tried and tested.

What happens is that the authors

are producing one version of the theory after another.

Usually the lifetime of their ideas is about one year,

after which it is replaced by the new set of ideas,

then by another set of ideas, then still by another set of ideas.

Not because they want to replace it,

but because the previous versions were disproved

by investigation of other people.

So that is something which unless the whole line of research

and claims and statements, will become more accurate.

This is something which undermines the whole idea.

So far just about every prediction made by inflationary theory

has checked out in many, many observations.

So it's not surprising that people like Andrei Linde are sometimes irritated

by what they sees as speculative mathematical attacks on inflation.

But it's not quite a done deal.

And while there is any doubt, the likes of Neil Turok feel

that it is their duty to point out where those doubts lie.

They are basing their theory on shaky foundations.

They cannot explain what happens before inflation.

And I think they've got themselves into a whole host of puzzles

to do with eternal inflation, and in a sense,

not being able to predict anything.

So I feel that we ARE being constructive.

We're putting forward an alternative, one which can be proven wrong,

and one which I think

may in time become much more complete and satisfying

than the theory of inflation.

Ever since the idea of the big bang, people have wondered what caused it.

What made everything apparently spring un-bidden from nothing?

Might it be that Neil Turok's right,

that the miracle was due to colliding branes in another dimension?

Or perhaps Lee Smolin has the answer.

Our big bang was simply the other side of a black hole in a galaxy far, far away.

Maybe it would be best, like Michio Kaku, to stop thinking of nothing as nothing,

but rather as just absence of stuff,

and to imagine bubbles of matter forming in a high-energy vacuum.

Is Param Singh correct?

No big bang at all,

just the big bounce,

again, and again, and again.

Or should we subscribe to Andrei Linde's Swiss cheese model,

and redefine the big bang as simply the inflationary energy of a mega-verse dying out?

Ten to the power ten to the power ten to the power seven times.

All of these ideas stray from the standard model of cosmology,

which holds that everything emerged from nothing at the point of the big bang.

And they would be easier to dismiss as the half-baked musings of the lunatic fringe,

were it not for the fact that some of the very people who constructed

the everything from nothing big bang model are themselves starting to dismantle it.

For many years, Professor Sir Roger Penrose spent much of his time

dismissing the very idea of "before the big bang" as a complete non-starter.

If people would ask me what happened before the big bang, my normal answer would be to say,

"The word before. What does that mean?"

Well, that's a sort of temporal concept.

And if the big bang was a singularity in space-time,

that means the very notion of time loses its meaning at this event,

this so-called big bang.

So if the notion of time loses its meaning,

the very notion of before loses its meaning.

So we would tend to say

it's a meaningless question to ask for before,

there wasn't a before, that's the wrong kind of notion.

And I would have perhaps gone along with this point of view,

until I've had some different ideas more recently.

Professor Penrose has concluded that to understand the origin of the big bang,

science needs to study the end of the universe.

The present picture of the universe is that it starts with a big bang,

and it ends with an indefinitely expanding,

exponentially expanding universe,

where in the remote future it cools off,

and there's not much left except photons.

Now what I'm saying is that in this remote future,

the photons have no way of keeping time and they don't have any mass.

You need mass to make a clock, and you have to have a clock to measure the scale of the universe.

So the universe loses track of how big it is.

And this very expanded universe

becomes equivalent to a big bang of another one.

So I'm saying that this, what we think of our present universe

is but one eon of a succession of eons

where this remotely expanding universe of each becomes the big bang of the next.

So small and big become completely equivalent.

If Professor Penrose is right,

our universe's expansion means that all its mass will eventually be converted to energy.

When that happens, conventional ideas of time and size disappear.

The contention is that because of this,

a nearly infinitely large universe

could just as well be the infinitely small starting point for the next one.

A cyclic system with a before and an after.

It's quite a volte-face for a man who was until five years ago a pre-big bang denier.

Let me say that a change of mind is not something unpleasant, I find,

it's something exhilarating.

Because you get stuck in a rut and that's what I find, you know,

you're thinking about certain things,

and after a while you think you're stuck into this rut.

And a change of mind, you think, "Ah, why didn't I think of it like that?"

That's extraordinarily exhilarating.

It is a huge turnaround.

For 50 years, the big bang,

stating that everything including space and time emerged from nothing, has been scientific fact.

And though what Professor Penrose and the others are suggesting is revolutionary,

it's worth remembering that revolutions in cosmology have happened before.

500 years ago, anyone suggesting that the earth orbited the sun would have been ridiculed,

and then arrested.

But from Copernicus to Galileo...

..from Hubble to Hawking,

the emerging cosmology has opened our eyes in stages to a bigger, truer picture.

What is now being proposed is nothing less than the promise of the biggest picture yet.

Probably the biggest picture possible.

But in science, ideas are just ideas until they are confirmed

or denied by observations.

And because the pre big bang ideas are so radical, the race to back them up is intense.

In rural England, there's a project under way that could seriously undermine inflation,

the mainstay of the current cosmology.

What we're doing today is building part of the world's biggest radio telescope.

Which will allow us to look back

to about a billion years after the big bang.

So we'll get a glimpse of the universe in its adolescent years.

Professor Bob Nichol is part of a team of academics constructing a new generation of radio telescope.

It's called the Low Frequency Array - LOFAR.

And though it lacks the iconic beauty of the 25 metre dish whose site it shares...

..its scientific ambition more than makes up for the aesthetic disappointment.

One of the foundations of cosmology is inflation.

And one of the great things about inflation is that it says on the largest scales in the universe,

the universe should be random,

and the galaxies and the matter should be distributed randomly.

So what we can do with this telescope is check that.

And if we don't see it, if it's not random,

then that's going to set the cat amongst the pigeons,

and someone's going to have to come up with a better idea

for what could have caused that non-randomness in the universe.

-What do you think?

-Ah, I think... I'm not paid to think.

I'm paid to make the observations.

I would love it, I would love it to be non-random.

That would just be fantastic, right? It would really just give us something new to think about.

And that's what being a scientist's all about.

If LOFAR removes inflation,

the whole of the standard model of cosmology would be called into question.

But if it confirms inflation, it will not only support the standard model,

it will leave most of the competing theories intact as well.

To settle those arguments, the ambition is nothing less than to observe the big bang itself.

Of course, we're 13.7 billion years too late to witness the actual event.

But in a quiet corner of Louisiana, they're looking for the next best thing.

They're hunting for gravity waves.

But gravity waves are such slight and shy beasts that finding them has not been easy,

even in the relative peace of rural Louisiana.

This is LIGO,

the Laser Interferometer Gravitational Wave Observatory...

..where Joe Giaimi is sniffing out the reluctant gravity waves with laser beams and mirrors.

This concrete enclosure

protects the stainless steel vacuum tube that encloses our beam,

and it goes on for the next four kilometres.

How come it has to be so long?

Well, the way gravitational waves work,

the longer the distance you measure,

the larger the change in that length you see.

And four kilometres was chosen because we could afford it, and we could find a plot of land that big.

A gravity wave is thought to be produced when cataclysmic events take place,

like the big bang.

OK, let's go.

The gravity waves that are theoretically produced by such an event

are thought to warp the very fabric of space and time.

And it's this warping that Joe is hoping to measure with LIGO.

LIGO generates a laser beam which is split into two

and then reflected off mirrors at the end of each 4km tunnel.

When the beams arrive back at the start of their journey,

they should still be in sync with each other.

If they're not, it might be that a gravity wave

has temporarily changed the relative lengths of LIGO's arms.

A bit.

The difference between those two lengths,

we're sensitive to that by less than 10 in the minus 18 metres.

So if this arm length were to change with respect to that arm length

bigger than that, bigger than 10 in the minus 18 metres, we could see it.

And what does that equate to?

10 in the minus 18 metres is 1/1,000 the diameter of a proton,

or 1/1,000 the diameter of the smallest atomic nucleus,

the nucleus of a hydrogen atom.

-And you can measure that?

-Yes.

24 hours a day, 7 days a week,

a patient band of physicists watch over the signal in shifts.

So while we're taking data, we always have two people in the control room.

TRAIN WHISTLE

Can I just stop there? What was train whistle?

OK, so... All right.

When we lose lock, which is what just happened,

that little train whistle goes off, because usually when we lose lock it's because of a train.

TRAIN WHISTLE

With tolerances so fine, measurement can be affected by almost anything that moves on earth.

Freight trains passing five miles away...

TRAIN WHISTLE

..means that operations cease.

So if we...

ALARM RINGS

Tornado warning.

Though the technology is in its infancy, its potential is huge.

LIGO is, in short, a prototype big bang detector.

And once the concept is proved on earth,

another interferometer will be built in space,

where arms three million miles long

will intercept the remains of the gravity waves theoretically produced at the beginning of time.

And it could go even further.

It could be that hidden in the signature of that first wave

is contained evidence of previous big bangs.

Good news perhaps for Param Singh and Roger Penrose when the satellites eventually fly.

It is the holy grail of science to turn theory into fact with concrete observations,

and for pre-big bang ideas, the evidence is proving frustratingly elusive.

But there is a scientist who believes that her idea

has actually has been backed up by not one, but three observations already.

Laura Mersini-Houghton's radical theory materialised, quite suddenly, in 2006.

I was teaching early at 8am in the morning.

And it was one of those large classes with about 100 students.

I'm not an early riser, so I wasn't happy about it.

However, I did manage to come and teach, and was done by 9am.

So I thought, "I deserve a coffee.

"Time for a coffee to wake up and plan the rest of the day."

Of course I'd been thinking about the big questions of cosmology.

Why did we start with this big bang and what was there before?

And suddenly this idea comes.

It was an idea that emerged from the fact that it's possible

to represent the entire universe not as an object,

but mathematically, as a wave.

Dr Mersini-Houghton's idea was to manipulate the mechanics of that waveform

with a branch of mathematics called string theory.

It seemed to provide an elegant solution as to why our universe emerged in the first place.

when you do that, and you calculate how that wave form evolves,

you do end up with the high energy big bang.

It seemed such a simple idea that in one hand I was very excited about it,

at the simplicity of the idea, and the fact that it gave a very coherent picture

of connecting different branches of physics.

But immediately after I was also thinking, "It's too simple."

On the face of it, the theory looks much like the others.

It predicts a multiverse, and at least one big bang.

But it stands out in one crucial respect.

It doesn't commit the scientific sin of assuming initial conditions.

It doesn't assume an earlier collapsing universe.

It doesn't assume pre-existing inflation.

And it doesn't assume a primordial black hole.

According to Mersini-Houghton, it assumes nothing at all.

as far as I know it's one of the few theories

where everything is derived from first principles and fundamental physics.

Nothing has been tweaked by hand or can be changed.

Even if I wanted to change a parameter,

the equations would not allow me to do that.

The other remarkable thing about the theory is that it fits with three observations,

phenomena which have defied conventional explanation.

There's an unexplained patch of nothing,

the so-called void in the cosmic microwave background.

And great swathes of galaxies have been found to be moving in the wrong direction.

Another finding shows there's something odd about the temperature in outer space.

According to Mersini-Houghton,

all these effects are due to the presence of neighbouring universes,

and are explained in precise detail by her theory.

I really started taking the theory seriously

only when the predictions that we derived were successfully tested.

Three unexplained, difficult to accommodate findings,

observational findings,

seem to just fall beautifully together in this theory

and hang together.

And it's a theory that would not only explain

the high energy big bang, but have a continuation.

A pre-big bang and after big bang part of the story.

So now you do know what happened before the big bang?

I think so. Yeah, I'm starting to believe it.

In the last ten years, cosmology has experienced a remarkable turnaround.

From insisting that there was nothing at all before the big bang,

most researchers now concede that there must have been something.

But understanding what that something was and how it worked,

means that cosmologists are having to give up many of their most prized certainties.

Whatever the fate of the ideas which are on the table now,

about the big bang and before the big bang,

it's inconceivable to me

that the universe really started at the big bang.

Why? Because that would leave so many basic questions unanswered.

What I certainly believe in is that

the big bang is just a very small event in this whole history of the universe.

And I think that itself is a big paradigm change.

Once we start thinking about things before big bang,

and we work on these theories,

maybe very soon we'll find an answer to how it all started.

My parents were Buddhists.

In Buddhism there is no beginning, there is no end.

There is just Nirvana.

But as a child I also went to Sunday school,

where we learned that there was an instant where God said,

"Let there be light".

So I've had these two mutually contradicting paradigms in my head.

Well, now we can meld these two paradigms together into a pleasing whole.

Yes, there was a genesis.

Yes, there was a big bang, and it happens all the time.

I'm open to almost any philosophical point of view, as long as it works,

and I want a theory that's ultimately tested by data and confirmed

that this is the way the world works.

The story of cosmology is a quest for the ultimate truth,

but one where crazy notions like the big bang sometimes turn out to be correct.

For a while, at least.

Its characters are men and women who defend their theories as passionately as any priest...

..who believe it is their calling to answer questions

that were once thought to be unknowable.

If you are not brave enough to ask strange questions,

if you are not brave enough to believe your own answers even if they are unbelievable,

then, well, OK, so you live your life, but then it is not completely fulfilled.

If you take courage to answer questions

in not necessarily the ways which other people expect you.

Sometimes you just end up saying stupid things.

Sometimes you end up saying something maybe wise.

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