BBC Horizon (2010) - What Happened Before the Big Bang? (uncut, complet)

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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