It is a good rule of thumb that, in science,
the simplest questions are often the hardest to answer.
Questions like, how did the universe begin?
In fact, until relatively recently, science simply didn't have the tools
to begin to answer questions about the origins of the universe.
But in the last 100 years, a series of breakthroughs have been
made by men and women who, through observation, determination
and even sheer good luck, were able to solve this epic cosmic mystery.
This was real astronomical gold.
I am going to recreate their most famous discoveries
and perform their greatest experiments...
30,000 km/s.
..that take us from the very biggest objects in the universe
to the infinitesimally small,
until I reach the limits of our knowledge by travelling
back in time to recreate the beginning of the universe.
The moment one millionth of a second after the universe
sprang into existence.
This is a time before matter itself has formed in any way
that we would recognise it.
It is as close as we can hope to get to creation,
to the beginning of time,
the beginning of the universe itself.
It is a remarkable fact that science took hundreds of years to come up
with a theory to explain the origins of the universe.
All the more surprising, given what a simple
and fundamental question it is.
There is something quintessentially human about asking the question,
where does all of this come from?
Perhaps because it is a deeper, more fundamental version of
where I come from?
Yet, for most of human history, the answers to such an apparently
simple question could only be attempted by religion.
It wasn't until the middle of the 20th century that science
built a coherent and persuasive creation story of its own.
It was a story based on theory, predictions and observation,
a story that could finally explain what had happened at the very
beginning of time, the beginning of the universe itself.
A little over 100 years ago, if scientists considered the life of
the universe at all, they considered it eternal, infinite and stable.
No beginning and no end.
So even framing the question about the origins of the universe
was impossible.
But at the beginning of the 20th century, that began to change.
New discoveries shook the old certainties
and paved the way for questions about where the universe came from.
One observation transformed our idea about
the true scale of the universe.
It began with a mystery in the sky.
By the early part of the 20th century, it was well known
that our solar system way within a galaxy, the Milky Way.
Every single star we can see in the sky with the naked eye
is within our own galaxy and, until the 1920s, all these stars,
this single galaxy, was the full extent of the entire universe.
Beyond it was just an empty void.
But there were some enigmatic objects up there as well,
just discernible to the naked eye that looked different.
And one of the most notable is Andromeda.
You can find Andromeda if you know where to look.
So, if you start from Cassiopeia, those five stars
shaped like a sideways letter M, if you move across from the point,
from the points of the M, slightly up is where you should find it.
Now, I'm going to use my binoculars to help me in the first instance.
And if I zoom across...
Yeah, there it is.
You can tell it's not a star. I mean, it's basically
a very faint smudge stuck between those two stars.
That is it straight up there -
that is M31, the great Andromeda nebula.
Now, they were called nebulae, because they had this smudgy,
sort of wispy, cloudy nature.
In fact, the word nebula derives from the Latin for cloud.
These indistinct objects were found scattered throughout the night sky.
Telescopes revealed many of these nebulae were far more complex
than simple clouds of interstellar gas.
They appeared to be vast collections of stars
and that raised two intriguing possibilities.
Were these stellar nurseries places where stars were born,
and therefore residing within our own galaxy, or,
much more profoundly, were these beautiful, enigmatic objects
galaxies in their own right sitting way outside the Milky Way?
The implications of that second possibility were enormous.
If true, it would instantly
and utterly transform our idea about the size of the universe.
Here was an opportunity for an ambitious astronomer to make
a real name for themselves.
Perhaps someone with a really big telescope.
Step forward this man - Edwin Hubble, a man from Missouri,
although if you had ever met him, you'd never have guessed,
because he developed this weird persona, a pipe smoking tea drinker
with a very affected aristocratic English accent.
Hubble is probably the most famous astronomer ever,
not least because of his consummate skill at self-promotion,
but also because of the incredible measurements he would make.
In Hubble's day, when it came to observations
and new discoveries, size mattered.
Today, this is the most powerful optical telescope in the world,
the GTC, with a primary mirror
over 10 metres, or 400 inches, in diameter.
Far bigger than anything Hubble had.
In September 1923,
Hubble was working at what was then the biggest telescope
in the world, the 100-inch Hooker telescope
at the Mount Wilson Observatory, perched on top of the
High Sierra mountains overlooking Los Angeles in California.
He was using the telescope to study one of the most prominent
nebulae in the sky, the Andromeda nebula.
The same nebula I looked at earlier, and it was while observing it
that one very special star caught Hubble's attention,
one that could reveal the true nature of Andromeda.
And I am going to use this telescope to look for it now.
This is the control room of the GTC and, tonight, they've pointed
the telescope at Andromeda and they are going to take a picture of it.
It takes about a minute for the exposure
- to give you a clear enough image? - That's right.
Now, the picture is finished, so we're going to open it.
OK, so, this is Andromeda here.
That's Andromeda, that's right.
And now, this is Hubble's original plate.
Right, now, Hubble's star is down here in this corner.
Can you find it in your image?
Yeah, if you take the image and you compare it,
you will see that we don't see that one.
What we see is the edge of the galaxy,
so we have to go a little bit further west...
- Oh, I see, so all this is just the edge. - That's the edge.
- I was assuming it was the centre of the galaxy. - No, no, no.
It just goes to show how much more resolution your telescope can get.
- That's right. - OK, so, can we see that particular star?
Yes, in order to find that particular star,
because it is so faint,
we have to look for references which are brighter.
And, in this case, you will see four stars in here,
which are these four stars.
- And the star Hubble found will be this one here. - That's it...
That tiny star is the one that Hubble found.
That's amazing.
And are you able to get a magnitude for that star?
Yeah, we have to do a little bit of processing on the image,
but we are able to get it.
OK. Hubble had found his star.
He knew it was special,
because he compared his plate with others taken over previous nights
and he noticed that his star changed in brightness -
some nights it was brighter, some nights it was dimmer.
He realised this is a variable star, and he saw the significance of it.
He could see that this was real astronomical gold.
His star was a Cepheid variable.
In the stellar bestiary,
Cepheid variable stars hold very special place...
..because, by studying the way their brightness changes,
astronomers can calculate how far away they are.
Hubble's Cepheid was the first to be discovered in a nebula,
so he knew that, if he could measure its period,
he would be able to work out its distance from us.
So, Hubble set about meticulously measuring
how his star's luminosity varied.
It's not hard to imagine how exciting
this must have been for Hubble.
At his fingertips was the opportunity to resolve
a fundamental yet simple question -
was this nebula within the Milky Way or beyond it?
The answer would reshape our knowledge of the universe.
Hubble measured the luminosity, or brightness,
of his star over many nights and plotted this curve here.
Now, when we measured tonight, we found it had a value of 18.6
and I know because they measured it last night to be slightly dimmer
that it falls on this side of the curve.
But more important is the period,
the time in days, from peak brightness to peak brightness.
Hubble measured this to be 31.415 days.
This is the critical measurement.
Armed with this and its apparent brightness,
Hubble calculated the distance to the Andromeda nebula.
It was immediately apparent that this star is very far away.
But when Hubble did his calculation, he worked out that it was
900,000 light years away,
making this star the most remote object ever recorded.
It could mean only one thing -
not only is Andromeda a galaxy in its own right...
..but it lies well beyond our own Milky Way...
..and the myriad of other elliptical
and spiral nebulae were also individual distant galaxies.
It was a moment in human consciousness when the universe
had suddenly and dramatically got considerably bigger.
With this observation, Hubble had redrawn the observable universe.
It might not have directly challenged
the idea of a stable universe,
but it shattered long-held assumptions and opened
the possibility of other bigger secrets,
like an origin to the universe.
Into this profoundly-expanded cosmos strode someone who would,
without realising it, provide the tools to unlock that secret.
This guy.
A story as great as one that explains
the origins of the universe would somehow feel wrong without involving
a scientist as great as Albert Einstein.
And so, of course, it does,
because it was Einstein who provided the theoretical foundations
needed to study the universe
and effectively invent the science of cosmology.
100 years ago, he proposed his general theory of relativity.
It turned physics on its head and gave us
a completely new understanding of the world.
He proposed that gravity was caused by the warping
or bending of space-time by massive objects like planets and stars.
His theories were revolutionary.
Einstein was a maverick who ignored the conventional
to follow his own remarkable instincts.
One of his lecturers once told him,
"You are a smart boy, Einstein, a very smart boy.
"But you have one great fault -
"you do not allow yourself to be told anything."
Of course, it was this very quality that would allow him
to change the world of physics and, of course, to mark him out
as one of the greatest thinkers of the 20th century.
And in 1917, he took his general theory of relativity
and applied it to the entire universe.
By following the logic of his theory,
he arrived at something rather unsettling -
the combined attraction of gravity from all
the matter in the universe would pull every
object in the cosmos together, beginning slowly
but gradually accelerating until...
Gravity would ultimately
and inevitably lead to the collapse of the universe itself.
But Einstein believed, like virtually everyone else,
that the universe was eternal and static and certainly wasn't
unstable or ever likely to collapse in on itself.
But his equations appeared to show the opposite.
In order to prevent the demise of the universe
and keep everything in balance, he adds this in his equation -
Lambda, or the Cosmological Constant.
It is a sort of made-up force of anti-gravity
that acts against normal gravity itself.
Now, he had no evidence for this, but it helped ensure
that his equations described a stable universe.
Within his grasp was the secret to the origins of the universe.
Yet Einstein simply couldn't, or wouldn't, bring himself
to accept the implications of his own equations.
With hindsight, it seems remarkable that Einstein did this.
I mean, here was a man who had revolutionised science
by rejecting conventional wisdom
and yet, he couldn't bring himself to trust his own theory.
He felt compelled to massage his equation
to fit the established view.
He even admitted that the Cosmological Constant
was necessary only for the purposes of making a quasi-static
distribution of matter, basically to keep things the way they were.
Whatever his reasons, this little character, Lambda,
would return to haunt him.
Because, while it prevented Einstein from understanding
the implications...
..his ideas opened the way for someone else to propose
a theory for the origin of the universe.
He was a young part-time university lecturer of theoretical physics.
His idea was so radical, it shocked the world of physics
and split the scientific community.
He started an argument that wouldn't be resolved for half a century.
His name was Georges Lemaitre.
Now, the eagle-eyed might spot the dog collar.
In fact, he was both a physicist and an ordained priest.
Of this apparently curious dual role,
Lemaitre said, "There were two ways of pursuing the truth.
"I decided to follow both."
And, using Einstein's theory of relativity,
he developed his own cosmological models.
Lemaitre's model described a universe that,
far from being static, was actually expanding,
with galaxies hurtling away from one another.
Furthermore, Lemaitre saw the implications of this.
Winding back time, he deduced that there had to be a moment
when the entire universe was squeezed into a tiny volume,
something he dubbed the primeval atom.
This was essentially the first description of what became known
as the big bang theory, the moment of creation of the universe.
These were revolutionary ideas and so he published them
in the Annales de la Societe Scientifique de Bruxelles,
where they were promptly ignored by the scientific community.
So, he travelled to Brussels to try to gain support for his idea.
The 1927 Solvay Conference, held here in Brussels, was probably
the most famous and greatest meeting of minds ever assembled.
But for our story,
the most significant meeting didn't happen here.
It wasn't planned and happened away from the conference.
It happened here.
In this park, the unknown Lemaitre approached the most famous,
the most feted scientist in the world -
Albert Einstein.
Here, finally, was his chance to explain his idea about an expanding
universe to the very person whose theory he had used to derive it.
You can only imagine Lemaitre's trepidation as he approached.
If Einstein endorsed his radical idea,
then surely it would be accepted.
Surely this brilliant mind, this titan of physics,
this deeply original thinker, would see the merits of his theory.
But after a brief discussion,
Einstein rejected his idea out of hand.
According to Lemaitre, he said,
"Vos calculs sont corrects,
"mais votre physique est abominable."
As far as Einstein was concerned,
his maths might have been correct, but his understanding
of how the real world worked was, well, abominable.
Once again, Einstein dismissed the idea of a dynamic universe.
Lemaitre's paper should have ignited science,
but without the backing of such a huge and influential figure as
Einstein, his ground-breaking idea was doomed to be quietly forgotten,
unless some observation or evidence showed up to support
the idea of an expanding universe.
Edwin Hubble, here, was riding high after his discovery that
proved there were galaxies outside of our own.
He was feted by Hollywood glitterati,
a guest of honour at the Oscars,
and, with access to the world's most powerful telescope,
he was ready for his next challenge.
He had heard of some unusual observations that many galaxies
appeared to be moving away from us.
No-one could understand why this might be.
So, in 1928, the world's most famous astronomer
turned his attention to this new cosmic mystery and began to measure
the speed that these galaxies were moving relative to Earth.
To measure the velocity that a galaxy was receding from us,
Hubble use something called redshift.
Now, it's not a perfect analogy, but the effect is similar to one
most of us are familiar with in sound -
the pitch of a car engine as it approaches us is higher,
because the sound waves are compressed,
but the pitch drops lower as the car recedes,
because the sound waves are stretched.
The effect is similar with light waves.
As the source of light moves towards us, the observed wavelength
is squashed towards the violet or blue end of the spectrum.
But if the source is moving away from us,
the wavelength is stretched towards the red end of the spectrum,
or redshifted, in the parlance of astronomers.
And the greater the velocity the object is receding,
the greater the redshift.
With his assistant, Milton Humason, Hubble spent the next year
carefully measuring the redshift of galaxies.
And I have got the chance to do the same thing right now
using this telescope.
OK, Massimo, have you found a galaxy for me?
Yes, I found this galaxy.
So, how far away is this?
It is approximately 430 megaparsec far.
So, if you convert that to light years... 430 x 3.26...
So it's about 1.5 billion light years away.
- Yeah, yeah. - OK.
Hubble needed to measure the average light coming from the galaxy
in order to get a spectrum, so that he could calculate the redshift.
Now, Humason did this by exposing a photographic plate
and it took him a whole week to collect enough light
to get the spectrum.
But here at the TNG, the Galileo Telescope, they use instead
a very sensitive chip that can do this much more quickly.
How long does it take for you to get a spectrum?
Approximately 10, 15 minutes.
So, 10 or 15 minutes' exposure compared with a week
back in Hubble's time -
far more powerful than anything they had back then.
- It's done. - The spectrum is quite good.
Ah.
OK, so this is the raw spectrum that has been taken.
Is there a particular emission line here that you will
- use as your reference to measure the redshift? - Yeah.
Here, for example, you have an emission line,
but to obtain real spectra,
you have to clean it to obtain the final one.
- Ah, this is the cleaned-up version of that. - Yes, of that.
- So this is the actual emission lines from the galaxy... - Yes.
And this one below, I guess, is the reference?
The reference, correct,
of a galaxy with redshift zero.
- OK, so one that isn't moving away relative to us. - Yes.
And so it is very clear here, if you compare the top one with this one,
every emission peak is shifted.
It's shifted in the red.
The reference line for the sample is H-Alpha,
and, from these, you can compute the redshift of this galaxy.
And can you work out from that how fast
the galaxy is moving away from us?
In principle, you can obtain this.
OK, so what is the formula?
The formula is the difference between the reference wavelength
and the observed wavelength,
divided by the reference wavelength and multiplied by C.
This is the Doppler effect.
- Let's see if we can do that roughly. - Yes.
OK, so this is about...
7,200, approximate.
OK.
Minus 6,563.
- ..63. - OK. - Over...
6,563.
- And that is the fraction of the speed of light? - Yes.
OK, so, I might as well do this.
I should do it with my calculator, but...
So...
OK. So then that we divide by 6,563.
OK, so it is roughly 0.1 the speed of light.
So it is about 30,000 km/s, yes?
- Correct. - Thank you.
OK.
I'm actually quite pleased at my maths here,
because I was under pressure.
So, this galaxy is 1.5 billion light years away from the Milky Way
and, from the redshift,
we have worked out it is moving away from us
at 1/10 the speed of light.
That means it is moving away from us at three...
At, sorry, 30,000 km/s.
Boom.
Science.
Once he had calculated the speed of the galaxy,
Hubble then measured how far away it was.
Once Hubble had both his measurements,
he could start putting them on a graph of velocity against distance.
Now, he made 46 different measurements
and, when he put them on the graph, he noticed a pattern emerging.
He could draw a line through all these points -
each one of them is an individual galaxy.
He noticed a connection between the velocity
and the distance of a galaxy.
In fact, the further away it was,
the faster it was moving away from us.
In a stable universe, the speeds of galaxies should appear random.
You wouldn't expect a clear relationship
between the distance of a galaxy and its velocity.
Hubble's graph showed that the universe was expanding,
which has profound implications for the idea
of a beginning to the universe.
What this means is that it is not just that the galaxies
are all speeding away from us and from each other
but that, if you could wind the clock back,
there would have been a time when they were all squeezed together
in the same place.
Here, finally, was the first observation,
the first piece of evidence that Lemaitre's idea of a moment
of creation, of a universe evolving from a Big Bang,
might be correct.
Thanks to Hubble's work, Georges Lemaitre,
the unknown Belgian cleric,
the theoretician without proper international credentials,
the man whose physics Einstein called abominable,
was belatedly rightly recognised for his bold theory.
Most significantly,
the biggest name in physics came around to this revolutionary idea.
In 1931, on a visit to Hubble's observatory,
Einstein publicly endorsed the Big Bang expanding universe model.
"The redshifts of distant nebulae
"has smashed my old construction like a hammer blow," he said.
Einstein dropped the cosmological constant. He even wrote to Lemaitre,
"Ever since I introduced the term, I have had a bad conscience.
"I am unable to believe that such an ugly thing
"should be realised in nature."
It must have been quite an absolution for Lemaitre.
Having been practically cast out into the scientific wilderness,
he was now firmly at the centre of a cosmological revolution.
The idea of the Big Bang was finally gaining traction.
But, despite Einstein's seal of approval,
and the observations of Hubble,
the argument was far from over.
There were still significant objections
if the idea of a Big Bang was to be widely accepted.
A scientific theory of creation isn't just about explaining
the expansion of the universe -
there were more profound issues to resolve.
The problem was, the Big Bang raised as many questions as it answered.
Like, if the universe had erupted from a single point,
where did all the matter come from?
To go further, the Big Bang theory needed to explain
how matter itself had been formed.
Well, before that could be answered, we need to know
what the universe is actually made of - the elemental building blocks.
And working that out took an incredible bit of insight
by a remarkable woman - Cecilia Payne.
She studied at Cambridge University, but wasn't awarded a degree,
because, well, she was a woman.
So, to continue to her studies,
she needed to go somewhere more enlightened.
She left England for America
and it was there that she revealed the composition of the universe.
If you were to ask someone what the most common elements were,
an atmospheric scientist might say nitrogen.
After all, it makes up more than three quarters of the atmosphere.
A geologist might say silicon or iron or oxygen...
which all seems very quaint and Earth-centric
and really rather parochial.
So, astronomers thought it better to look at the sun.
Which makes sense, given that most of what we see
when we look out into the cosmos is stars.
The first attempts to analyse the composition of the sun
were done with a set-up rather like this.
Well, not exactly like this -
this is a cutting-edge 21st-century solar telescope.
But the basic idea was exactly the same.
The basic idea's very simple.
The sun's light is reflected off this mirror here,
up into a second mirror...
where it bounces off, down through the top of the tower,
all the way to the bottom, ten storeys down,
where it's focused and split into a spectrum and analysed.
This is the control room of the solar telescope.
The base of the telescope is over there.
And here, I've got a live feed image of the sun.
And what I've got up here is a zoomed-in section
of the spectrum of the light coming from the sun.
Now, it's in black and white,
but it actually corresponds to the green part of the spectrum.
These two thick dark lines correspond to the element iron.
They tell us there's iron in the sun.
Now, here I have the spectrum in much more detail,
and these two lines correspond to these two dips
in the absorption spectrum
at very specific wavelengths. This is iron.
If I look at different parts of the spectrum, I can see other elements.
This big dip here is hydrogen. These two dips represent oxygen.
And this dip corresponds to the element magnesium.
All these dips and lines in the spectrum
indicate the presence of these elements in the sun's atmosphere.
Effectively, a fingerprint of the sun's composition.
To a geologist, these elements are all very familiar.
It appears, at first glance, that the sun is made of the same stuff
as the Earth, that the sun is simply a very hot rock.
And that would have been that
were it not for the insight of Cecilia Payne.
She realised that the spectrographs were being affected by processes
in the sun's atmosphere.
These would distort the apparent abundance of the elements
that make up the sun.
So, she recalculated the relative abundances of the elements
and discovered that the sun was composed almost entirely
of just two elements -
hydrogen and helium.
All the other elements - carbon, oxygen, sodium, iron -
that made the sun seem so Earth-like
amounted to just a tiny fraction of its composition.
When she first presented this result,
it was considered impossible.
In fact, when she wrote up her work,
she was persuaded to add the comment that these calculated abundances
of hydrogen and helium were almost certainly not true.
The idea was only accepted some four years later,
when the director of a prestigious observatory
arrived at exactly the same conclusion by different means.
Ironically, this director was the very same man
who'd initially dismissed Payne's work as clearly impossible.
Payne's revelation about the ratio of hydrogen and helium was found
to be remarkably consistent for almost every star in the galaxy.
That led to a big conclusion.
The universe is dominated by just two elements, the simplest
and lightest elements - hydrogen and helium.
Together, they make up more than 98% of all the matter in the universe.
All the other elements that are so important to us -
like carbon, oxygen, iron - amount to less than 2%.
So now the challenge for supporters of the Big Bang theory
was very clear and simple -
could the Big Bang theory explain the creation
AND the observed ratios of hydrogen and helium found in the stars?
But to answer that would require a fundamental shift of emphasis.
Rather than consider the almost infinite vastness of the universe,
it was necessary to consider
the infinitesimally small world of the atom.
And that required, not an astronomer,
but an entirely different kind of physicist.
George Gamow was a Russian nuclear physicist
and an enthusiastic advocate of the Big Bang idea.
He turned his attention to the earliest moments of the universe.
Here, he felt,
was where the answer to the composition of the universe lay.
This was when he believed hydrogen and helium were first forged,
and he proposed it would have happened very soon
after the birth of the universe.
He set about building a mathematical model
of the earliest stages of the universe.
He was thinking about the universe in terms of seconds and minutes,
rather than billions of years.
And he recruited a young protege,
this chap, Ralph Alpher, to help him.
After years of hard work, some of which, according to Alpher,
were aided by hard drinking in a bar,
they presented their idea.
By rewinding the universe, it was clear to them that there
would have been a time when the early universe was incredibly dense
and phenomenally hot.
At this stage, which they calculated to be just three minutes
after the Big Bang, the universe would have been so hot
that atoms themselves couldn't exist,
only their constituent parts,
a kind of superheated primordial soup
of protons, neutrons and electrons.
They even gave this soup a name - ylem,
from an old English word for matter.
Then came the crucial moment...
a time when conditions were right for the nuclei
of the first elements to be forged.
In a short period of time,
which they estimated to be less than 15 minutes,
hydrogen nuclei proton were coming together to form helium,
in the process of nuclear fusion.
Moreover, the ratios of hydrogen and helium predicted by their model
matched that measured in the stars.
They announced their results in a paper published in 1948.
However, Gamow added another author to the paper -
the famous nuclear physicist, Hans Bethe,
who had nothing to do with the work.
Gamow added his name for a laugh.
He thought it made a good science pun,
because the authors of the paper now read, "Alpher, Bethe and Gamow."
The young Alpher, however, was less amused to be sharing the credit
with someone who'd done no work.
By way of reconciliation, the story goes,
Gamow produced a bottle of Cointreau for Alpher
but with the label changed to read, "Ylem."
The ability to make calculations that explained the origins of matter
in the first few minutes after a Big Bang was remarkable in itself.
But there was a very significant prediction
that emerged from their work.
A prediction that had the potential to deliver the proof
that the universe had begun with a Big Bang.
Alpher continued to study the early evolving universe,
focusing on what happened next.
He pictured the universe at this stage as a seething fog
of free electrons and atomic nuclei.
Then it dropped to a critical temperature,
a temperature cool enough for electrons to latch on
to the nuclei of hydrogen and helium.
At this precise point,
light was released to travel freely throughout the universe.
The first light of creation.
This might have remained nothing more than an academic curiosity
had it not been for Alpher's insight.
You see, he realised that this light from the beginning
of the universe should still be reaching us now,
after billions of years.
Very weak, very faint, but observable in all directions.
He calculated that the expansion of the universe should be stretching
the wavelength of this light beyond the range of the visible spectrum
and should now be arriving as microwave radiation.
So, find this predicted ancient microwave signature
and it will prove, not just the theory of the early evolution
of the universe, but the entire Big Bang theory itself. Simple.
The problem was, this was the late 1940s
and no-one had any way of detecting such a weak signal.
The acid test was quietly forgotten.
Supporters of the Big Bang now had the prediction
and observation of an expanding universe.
And a theory for how elements were forged
in the first few minutes after the Big Bang.
But without the clinching evidence for this, the argument over
whether the Big Bang theory was correct rumbled on.
The opponents of the Big Bang continually tweaked and adjusted
their theories to make their idea of an eternal and infinite universe
fit the new observations.
The scientific community was still pretty evenly split.
Conclusive proof of the Big Bang theory would eventually emerge
some 15 years later.
It would be revealed quite unexpectedly
by two young radio engineers.
In 1964, Arno Penzias and Robert Wilson -
that's Penzias on the right there -
discovered something so momentous, it won them the Nobel Prize.
This telescope is dedicated to study their accidental discovery.
In 1964, Penzias and Wilson were working at the Bell Laboratories
in the US where they were given this, a bizarre
and obsolete piece of kit to play with.
It looks, for all the world, like an enormous ear trumpet.
But when they turned their telescope on,
they found that the sky was saturated with microwave radiation.
All warm bodies emit microwave radiation,
whether it's from the atmosphere or from the instrument itself.
And today's mobile communications flood the sky with it.
FAINT STATIC
So, before they could do any useful measurements,
they had to calibrate their Horn Antenna to see
if they could reduce this "noise."
FAINT STATIC
Even after accounting for the atmosphere
and their instrumentation -
of course, there were no mobile phones to worry about back then -
they were still left with this persistent
and deeply irritating background noise.
It was registered on their instruments as a radiation
with a constant temperature of three degrees above absolute zero,
a microwave hiss that they couldn't get rid of
no matter what they tried.
FAINT STATIC
Even more annoying for them was the fact that it seemed to be
everywhere they pointed their celestial ear trumpet.
They were about to give up when Penzias attended a meeting
where he casually mentioned this irritant to a colleague.
A few weeks later, the same colleague phoned him up and said
he knew of some researchers in Princeton
who are looking for just such a signal.
Unwittingly, Penzias and Wilson had stumbled upon
that predicted radiation - Alpher's burst of light
from the early evolution of the universe.
Here, at last, was proof of the Big Bang theory.
It's quite remarkable to think that this microwave radiation
has travelled across the furthest reaches of space,
from 13.8 billion years ago
when that first light from the Big Bang was released.
As Penzias himself said, when you go outside,
you're getting a tiny bit of warmth from the Big Bang on your scalp.
And, yes, I probably feel it a bit more than most.
Almost 40 years after Lemaitre first postulated it,
the idea of the Big Bang had finally entered the scientific mainstream.
But the discovery of this cosmic microwave background radiation,
the CMB, and the proof of the Big Bang theory itself,
isn't the end of our story.
We've probed back to the first few minutes after the Big Bang.
And beyond this lies a new frontier of knowledge.
There are still very big questions to resolve about the beginning
of the universe, questions like,
"Where did all the matter itself come from?"
And "How do you get something from nothing?"
The answers to these questions lie further back,
hidden behind the curtain of the CMB.
Their secrets lie in the primordial universe,
within the very first second of its existence.
This is where the edge of our understanding now lies,
and this is where scientists are focusing their efforts...
not by looking into the skies,
but here on the border of Switzerland and France.
More specifically, at CERN,
with the largest particle accelerator in the world,
the Large Hadron Collider, or LHC.
Now, you might be wondering what a particle accelerator has to do with
the early universe, because the connection between the two
is far from obvious.
The thing to remember is that, when the universe was very young,
it was much smaller and so all the matter -
everything that makes up the stars, the galaxies, black holes -
all had to be confined into a much smaller space.
At that stage, the universe was phenomenally hot and,
more significantly, its energy density was very high.
It was then that the first matter sprang into existence.
The LHC can't yet replicate that process...
..but it can allow us to study the properties
of these fundamental particles.
Once a year, the LHC stops its normal business of colliding
beams of protons, and instead uses much more massive particles
to create collisions with energies more than 80 times greater
than that produced from two protons.
They do this by accelerating atoms of lead,
stripped of all their electrons,
up to speeds close to that of light,
and smashing them together.
And that lets us see something pretty special.
The collisions are so intense that, for a moment,
we create something unique -
a world not of atoms or even neutrons and protons -
but of quarks and gluons and leptons - exotically named particles
that came together to form atoms in the first millionth of a second
after the Big Bang, and have been locked away ever since.
Down there, underneath that lead shielding, we're recreating a stage
in the universe's evolution called the quark-gluon plasma.
Now, this is the moment immediately before the quarks become trapped
by the gluons to create protons and neutrons,
which themselves go on to form the nuclei of atoms.
The phrase we use - grandly -
is the confinement of the quarks.
To develop the necessary energy,
the lead nuclei are passed through a chain of smaller accelerators,
gradually ramping up the energy until they're finally
fed into the largest accelerator on Earth, the LHC.
Now, the maximum energy a beam can achieve is directly related
to the size of the accelerator,
and the LHC has a circumference of 27km.
That means the beams here can achieve an energy
of 1,000 tera-electronvolts.
Now, actually, that's less than you might imagine, because
it's equivalent to the energy that a housefly hits a window pane.
But the critical difference here
is that the energy is concentrated,
it's the energy density that's important.
The LHC can squeeze all that energy down to a space that's less than
a trillionth of the size of a single atom.
This is something that can happen nowhere else in the known universe.
The two beams of lead nuclei are travelling around the ring
in opposite directions.
They're meeting deep underneath this control room at the detector.
We can see live feed pictures of the detector up on that screen.
Now, underneath us,
they're travelling at a speed of 99.9998% the speed of light.
That means they're covering the full 27km circumference of the ring
more than 11,000 times per second.
When the beams reach maximum energy -
and we can see up there, it says "iron physics stable beams" -
that means they can be crossed.
Just like in Ghostbusters.
At that point, a tiny fraction of the lead nuclei will collide
and create a super-hot, super-dense fireball
with a temperature 400,000 times hotter than the centre of the sun,
and a density that would be equivalent to squeezing
the whole of Mont Blanc down to the size of a grape.
That looks like a fantastic image there.
- Can you tell me what we're seeing? - It's amazing, actually, isn't it?
It's literally tens of thousands of particles and antimatter particles
- flying out - this kind of aftermath of this explosion. - Right.
So the coloured particle trails here
AREN'T the quarks and gluons themselves,
but evidence of the quark-gluon plasma created by the collision.
We have to infer its properties from looking at the debris
that flies out. It's a bit like working out how an aircraft works
by looking at the debris of a plane crash. That's what we see.
What I find amazing is, what we're doing here is trying to recreate
that moment in the early universe where the quarks and gluons
were all free to float around, cos the energy was so high,
and then it cooled and they stacked together. You're doing the opposite.
We're starting with normal matter, smashing it together,
and going back to that unconfined state, that plasma.
Yeah. I like to think about it as a time machine.
We're actually winding back the clock.
And this is the only way that we can study the properties of free quarks,
because these quarks have been imprisoned inside particles
like protons and neutrons for 13.8 billion years.
That's pretty incredible, isn't it? Finally, after 13.8 billion years,
you can set these quarks free -
- even if it's for a fraction of a second. - Yes.
While we don't yet know how matter sprang into existence,
studying these collisions allows us
to make the first tentative steps towards that discovery.
What we've just witnessed is the earliest stages of the universe
that anyone - anywhere - has been able to observe.
It's the closet we've got to the moment of the Big Bang.
And, let's face it, it's not bad.
One millionth of a second after the Big Bang itself.
Even going this far back in time
still leaves physics with unanswered questions.
Beyond this is where some of the deeper mysteries of the universe
are hiding. How the fundamental forces that bind matter together -
gravity, electromagnetism and the nuclear forces -
are connected to each other.
How the particles that make up matter itself
condensed out of a fog of energy.
How mass is generated from the force that binds protons
and neutrons together.
And how the universe itself underwent a super-fast expansion
in one billion-billion- billion-billionth of a second
to create the structure of the cosmos.
At the moment, we have no way of observing any of these phenomena.
This is the realm of abstract theory and speculation.
If we're ever going to replicate this early stage of the universe's
evolution, we're going to need to create considerably higher energies.
Frankly, we're going to need to build a bigger collider.
And that's a problem. And it's not just one of expense,
although it would be phenomenally expensive.
No, it's more one of finding the room to build it.
Remember when I said the energy's related to the circumference
of the accelerator? Well, the LHC, down below me,
has a circumference of 27km.
It runs beneath the Jura Mountains
and straddles both France and Switzerland.
In order to look back and observe the universe at this earliest stage,
well, we'd need to build an accelerator
with a circumference larger than the orbit of Pluto.
Revealing the origin of the universe begs another,
even more profound question -
how will it end?
Next time, I discover whether the universe will end with a bang
or a whimper.
Want to discover more about the beginnings of the universe?
Go to the address below and follow the links to the Open University.