Cosmic Dawn: The Real Moment of Creation Horizon

In the beginning, the universe was a bit of a let down, really.

For millions of years after the Big Bang,

things were actually rather boring.

It's just this...soup.

The Big Bang was not the moment of creation.

The real moment of creation came 100 million years later.

There was this magical, if you like, metaphysical moment.

The cosmic dawn.

The moment of first light.

It's the moment the first stars were born...

The first stars are fundamental to how the universe evolved.

They're like the rock stars in the universe.

They live fast and die young.

..the moment that lit up the universe...

For the first time in cosmic history,

the universe really is getting interesting.

..and began forging the ingredients that made you, me

and everything around us.

It was the starting point that led to the appearance of life.

Astronomers are now trying to witness

and understand this moment of creation.

I guess what we're trying to achieve is to see the beginning of things.

THUNDERCLAP

We are dealing with a scientific version of the story of Genesis.

Let there be light!

This is the Murchison country, Mid West, Western Australia.

It's the ancestral home of our people, the Yamaji.

It's very remote and the night skies are something special.

I like how it's flickering there.

It's like, if you come...

Our people like to tell stories and paint pictures -

stories about the land, about the stars,

about how things got here.

And there's Venus, beautiful and bright too. Look at that.

Sometimes it's the morning star, sometimes it's the evening star.

That's in a story from the Kouri people, over in the east,

that when Venus comes this way, they say hello to us

and then, we say hello to them.

-When it goes back?

-Yes.

Oh, nice, that's a nice thought.

Many people tell stories about creation and how we got here.

This is Steven Tingay. He's an astronomer.

-That's Orion.

-That's Orion's Belt.

It's just dark enough to see the saucepan, the three stars.

That's that one over there.

He knows a lot about the stars,

but he didn't know about the emu in the sky.

The emu in the sky tells a story about our ancestors,

how they used to gather food

and that emu in the sky

would tell them the right time to go out hunting.

It's all about collecting our bush tucker.

When you see the emu's laying, that's the time -

and then, when the emu is standing, that's the season over.

I've been looking at the night sky since I was six years old

and looking at the Milky Way for decades,

and never, ever saw it.

I forget who it was that pointed it out and said well, you know,

there's the emu's head, neck, body and I've just gone...

whoa!

That's been there all the time that I've been looking at it

and I've never seen it.

It was mind-blowing.

Steven's looking for more discoveries in the sky.

He's trying to put together his own story about how we got here,

the scientific story of our creation.

He's built himself a giant radio telescope out here on our land,

to tune into something no human has ever seen -

the moment the first stars were born,

the first light was made,

and the first stuff that made all of us.

Some people call it the moment of creation.

This may be our land,

but it's a story about every single one of us.

THUNDERCLAP

Steven Tingay is not alone.

Here at Harvard, Avi Loeb is also hoping to build up

a complete picture of the life story of the universe...

..to assemble a cosmic photo album

that traces our story right back to the beginning of time.

Our cosmic family book.

That's an image of the earth from the moon, a quite beautiful image.

This is our home and, of course,

we would like to trace our cosmic roots

all the way back to where we started.

We have some brilliant pictures of our universe

as it is today - as an adult.

Our solar system,

our Milky Way galaxy

and our galactic neighbours.

And if we go to the very beginning of the album,

we also have one picture of the universe as a newborn baby.

Where it all began.

It's called the cosmic microwave background.

This is an image of the infant universe,

and that image shows us the conditions

in the very early universe.

The picture tells us without doubt

that our story started with a hot, dense and bright beginning.

The Big Bang,

often credited as being the moment of creation.

The Big Bang arranged the initial conditions of the universe.

Early on, the universe was very bright.

The temperature of radiation was very high,

much higher than we find at the centres of stars nowadays,

but as the universe expanded, it cooled off.

And as it cooled, the universe became darker and darker.

The lights went out

and our universe was nothing more than a vast black fog of hydrogen.

Welcome to the dark ages.

Several million years after the Big Bang,

the universe was dark and boring,

filled with cold hydrogen atoms floating through space.

All the things we treasure did not exist.

The Big Bang was not the moment of creation.

The Big Bang gets all the credit,

but in reality, it merely set the stage.

It created space and time, a brief flash of light and some fog,

but nothing that you and I would recognise

as our present day universe...

..and it left us with the longest interval in history -

the dark ages.

Then, we get to the dark ages.

We don't have photos of those.

These are the missing pages in our photo album.

The dark ages are the last great frontier in our cosmic history.

The universe, the cosmic photo album.

Yeah, that's worth a blow-up.

I guess this is the famous cosmic dark ages.

Astronomers are desperate to fill in the missing pages,

the childhood years of our universe...

It's still blank.

..to see the moment of transformation,

when the dark fog gave way to a universe of light...

These are the bits that we want to fill in.

How dark is it?

..to see the first stars in the cosmic dawn,

the real moment of creation.

The first star probably formed about here.

Somewhere in these pages.

To reach this moment in our cosmic history,

astronomers have devised some extraordinary techniques.

At the Edinburgh Royal Observatory,

Jim Dunlop and Ross McClure

are trying to see the cosmic dawn by tunnelling deep into space.

What we're trying to achieve is see the beginning of things,

see when the first structures in the universe formed -

first stars, first galaxies.

And to do that, they have been using the Hubble space telescope

to take one of the most important pictures ever.

We're looking at an ordinary patch of sky,

in this case, a little bit to the right of Orion,

but it's a tiny, tiny area, smaller than my fingernail.

It looks blank to the human eye.

It may look blank with the naked eye,

but Hubble is allowing Jim and Ross

to tunnel deeper into the distant universe than ever before,

in their search for ancient light from the cosmic dawn.

We're trying to look back as far as we can,

to the beginning of time,

as close to the Big Bang as we can manage.

Here we have Orion, a constellation that many people will recognise,

and we're zooming in, tunnelling in.

To collect the faint light

from the most distant objects in the universe,

they use what may be the longest exposure in cosmic history.

During the course of 650 orbits,

they pointed Hubble at the same tiny thumbnail patch of dark sky

for 100 hours.

So we go deeper, tunnelling into deep space

and then we start to see very faint galaxies appear.

As they tunnel,

they are reaching further back in time,

because the further away something is,

the longer its light has taken to reach us.

And what we see of a distant object

is how it looked in the distant past.

One of the simplest ways to look at it is to realise

that even the sun is seen as it was eight minutes ago.

So, if the sun disappeared,

we wouldn't know for eight minutes and if Jupiter disappeared,

we wouldn't know for about an hour, or something like that.

What's really staggering is that once you get to the nearest galaxy,

that delay is already several million years.

Which means that we're seeing these galaxies as they were

millions of years in the past.

Deeper down the tunnel,

there are galaxies that we see as they were

many billions of years ago.

And here, we start to come into this image of what's called

the Hubble ultra deep field and these galaxies now,

we're seeing back to within a billion years or so of the Big Bang.

This here is the deepest ever image of the night sky ever taken.

The deepest image shows the oldest things -

galaxies that formed less than a billion years after the Big Bang.

That tiny - if you like - borehole that we've made into the sky,

it is a window into a very different time.

For three months, Jim and Ross had exclusive first access,

looking through this window in time...

We were the first people to look at this data.

..and they set about analysing the ancient light

for signs of the earliest stars and galaxies.

There was this one object in there,

from the thousands that were in that image,

that we identified as being potentially the most...

the most distant object that ever had been seen by anyone.

This one here is the most distant of all.

This is zoomed in. It's just literally a faint blob

and there's only a few photons of light

being collected to see this object, which we're seeing

only 500 million years after the Big Bang.

This faint blob turned out to be an entire galaxy.

You see, it's not a star, it's not point-like.

You can see it's slightly extended, which proves it's a galaxy -

I think about 20 times smaller than our Milky Way.

But that's about all we have on this galaxy.

We can't even measure its colour very well.

It's only just detected by Hubble in its very reddest wavelength.

It's an excitement, to be the first person to ever look at that image

and from that image,

to see this object that nobody's ever seen before.

And until the next generation of telescopes come online,

it's as far away as we can possibly see.

This was, interestingly,

the most distant object you could see with Hubble.

Hubble's incapable of seeing any further than this object.

I guess it also means no-one's going to pip you for the next few years?

Correct.

-We are the record holders for a few more years.

-Yeah.

Ross and Jim have identified the earliest galaxy ever found.

It was born more than 13 billion years ago.

You can do the sticking, since you've got young kids,

so you're used to this stuff.

It's a picture that takes us right to the edge of the dark ages.

Which way up is it?

We've filled one more page in the cosmic album,

taken one step closer to creation,

but for now, that's the limit.

Using this method,

the cosmic dawn and the very first stars

still remain tantalisingly out of reach.

But it is only one method.

What if even older objects could be found elsewhere in the universe?

At Siding Spring Observatory, in Australia,

Stefan Keller is also searching for the first stars and the cosmic dawn,

but not by staring across the entire universe.

He's looking much closer to home for some very unusual stars.

The star we are most familiar with is, of course, our own sun.

Here we are on top of a mountain,

catching the last rays of the sun,

and the sun is very special for us,

but it's a very average sort of star.

It's been around for about 4.6 billion years,

a third of the lifetime of the universe.

That may sound a long time,

but it's pretty typical for stars in our galaxy.

And among the 200 billion stars of the Milky Way,

Stefan is searching to see if any truly ancient stars

may have survived since the very beginning.

What we are looking for are those very rare stars

that are amongst the oldest stars that are out there.

But spotting a truly ancient star is no easy task,

when all you have to go on is a pinprick of light.

The light is all that we have to work with.

We need special ways of dissecting the starlight that is coming to us,

so that we can understand where they've come from, how old they are.

When we decode that, we can uniquely identify

some of the older stars that remain with us today.

The secret to spotting an extremely old star

is to see what it's made of.

It's all down to a process of cosmic recycling.

Stars are fundamental to life,

because they're the furnaces

that have created everything that we need on earth.

The rocks that we see have been formed inside a stellar interior

and then thrown back out into the universe.

The gold and the silver in the rings on my finger,

they've all been made in a supernova.

There's no other place in the universe

that you can create elements like that.

After a lifetime forging elements as heavy as iron,

a star will eventually run out of fuel.

Many then explode in a massive supernova,

spewing out a cloud of debris into interstellar space.

This rich cloud is then recycled into the next generation of stars.

Again and again and again, this cosmic recycling is taking place.

In a star like the sun,

there have been about a thousand generations of stars before it.

Each generation has a richer and richer composition

of heavier and heavier elements,

and particularly noticeable is the build-up of iron.

So, the amount of iron is an arrow of time.

It shows us how old the star is.

If you want to find a very old star

from the beginning of the recycling process,

you need to find one with very little iron.

The way to do that is to look for a specific

but minute variation in colour,

something that Stefan's robotic Skymapper telescope

is carefully designed to spot.

So, our sun has a particular yellow colour.

If we then looked at a star of similar temperature,

but which was much older,

it would have an ever so slightly different colour.

It's slightly bluer and so, by looking for stars

that are ever so slightly bluer,

we can zero in on the needle in the haystack

and we can do that at a rate of about 100,000 stars per hour.

Each night, Skymapper captures the light from nearly a million stars.

It automatically analyses the colour of each one

and arranges them for Stefan according to iron content.

So, we see in most stars, like the sun, have quite a lot of iron,

but then there's this tail of objects

that don't have much iron in them at all,

and they're the potential needles in the haystack.

And in 2013, Skymapper presented Stefan with one particular star

that looked quite unlike any other.

Here you see 100 or so ordinary stars scattered around the field

and in the centre is the star that we discovered.

The initial reading from Skymapper

suggested that this star had an incredibly low iron content.

At first, we thought we must have done something wrong here,

but we confirmed it the next night

and that's when things really got exciting.

The next step was to take a much closer look

with a much bigger telescope.

We were lucky enough to find some telescope time over in Chile

and we stared at this one star the entire night,

building up a very detailed spectrum of the star.

There were a number of things that we saw

that we just hadn't ever seen before.

With enough light, it's possible to make a detailed spectrum

that can reveal the precise ingredients of a star.

What we see here is the spectrum of light

from a star that's similar to the sun.

This is like a fingerprint from the star

and it tells us how much iron, magnesium and calcium

is inside that star.

And you can see that there's quite a lot of lines here.

In the case of our star, which is up the top here, all we see

are the lines of hydrogen

and a little bit here, which is carbon.

And so, it's quite a different recipe and indeed,

we just don't see any iron detectable in this star

and we knew that we were onto something very exciting,

because we had never seen a star like this before.

A star with no detectable iron

must have been made very early in the process of cosmic recycling.

It's been around for 13.6 billion years.

It's a very pristine star.

It formed very early on in the history of the universe,

before much stellar recycling had taken place.

Stefan had discovered the oldest star ever seen.

It's been burning for 13.6 billion years.

Could it be a remnant from the cosmic dawn?

In fact, what we're able to do with this star is,

for the first time,

say that there was only one star that preceded it.

Stefan's star had to have been formed from the exploding debris

of one of the very first stars of the cosmic dawn.

Remarkably,

it is from only the second generation of stars ever made.

Stefan's discovery takes us

further back towards the dark ages than ever before.

His star is even older than Jim and Ross's blobby galaxy

and amazingly, it's right here in our own galaxy.

Ah, here we are!

That looks like the right spot.

This is a star that predates the Milky Way galaxy itself.

But we must go even further,

because even before this

came the very first stars of the cosmic dawn -

stars that lie beyond the reach of any telescope,

that we may never see directly.

So, how can we know what ended the dark ages -

how light and structure emerged in the very first stars?

What if we could visualise building them from scratch,

by going right back to

the individual atoms of that hydrogen fog?

If you go back to the this time of the dark ages,

the universe looked completely different.

If you had a human observer translated back in time,

you would see a completely dark, boring, featureless universe -

an utterly alien place, it would appear to us.

It was a universe without any light.

There were no stars, no galaxies.

Just a collection of lone hydrogen atoms

and the odd bit of helium,

spread out in a diffuse fog.

Hydrogen would be in its most primitive state -

single hydrogen atoms.

Basically, we would have, say,

a volume of the size of my stretched-out arms

and in this volume, you would basically have one hydrogen atom.

So diffuse, that if a hydrogen atom was the size of a ping-pong ball,

the next closest one would be almost halfway to the moon.

So, we have this very diffuse universe.

How do we get stars out of this?

Volker Bromm decided the only way to get a picture of the first star

was to build one from scratch,

one hydrogen atom at a time.

It was time to forget the telescopes

and bring on the supercomputer.

We can input into the supercomputers all the laws of physics -

from, as we say, first principle.

We can put in the initial conditions,

because initial conditions is what we see here.

There are no missing pieces.

We have all the laws of physics

that describe the behaviour of these basic ingredients

and at that point, we set up the computer and then we let it go.

The scale of the calculation seems impossible -

to model the behaviour of vast clouds of primordial hydrogen gas,

trillions of hydrogen atoms,

one interaction at a time,

and to ask the question...

..will they form a star?

At first, you might think this is hopeless.

How do we get things like stars out of this?

But what really then kicks in is the force of gravity

and the force of gravity has an infinite reach.

It reaches over vast stretches of the universe -

millions of light years, so the force of gravity is a very patient force.

Crucially, the distribution of matter wasn't completely even.

Tiny fluctuations left over from the Big Bang

meant some regions were slightly more dense than others...

..allowing gravity to work its magic.

Gravity would very, very slowly act

to clump matter together.

Certain regions of space, where the density of primordial stuff

is larger than the rest.

And then, what would happen is millions of years,

millions of years would create and attract more and more material.

Eventually, gravity could pull such a vast collection of atoms

so incredibly close together,

under such extreme pressure

that it would trigger nuclear fusion

and a star could be born.

But Volker's supercomputer simulations revealed a problem.

Something was stopping the first stars from sparking into life.

Gravity may be pulling the gas atoms closer together,

but there's another force trying to push them apart.

This comes together and you compress gas,

then it also is heated up and at some point,

the heat will basically have random motion -

and the random motion will basically prevent gravity

from condensing the gas any further.

The more the gravity squeezes inwards,

the more the gas heats up and pushes outwards.

It's a stalemate.

Later stars overcome this problem

because they come from a cloud enriched by heavier elements

that can readily absorb some of the heat,

letting gravity win the fight

and squeeze the gas beyond the point of no return.

But with no heavy elements,

how could the primordial gas get past the stalemate?

And then, the important question is, can this gas,

this primordial gas, can this get rid of the heat?

Volker realised there had to be

something else in the primordial gas,

or the universe would have got stuck.

What tipped the balance in favour of gravity

were a few chance encounters between the hydrogen atoms.

Very rarely, something very dramatic happened.

You have the two hydrogen atoms and they meet

and they form hydrogen molecules.

And crucially, a pair like this are able to absorb

a tiny bit of heat in a way that a lone atom can't.

This is the key process for the entire end of the cosmic dark ages.

The gas can cool, gravity can take over

and eventually create conditions

that are so extreme, in terms of temperature and density,

that you can trigger nuclear fusion

and can eventually form, out of this material, stars.

MUSIC: Lacrimosa by Zbigniew Preisner

The first star is born.

The first light of the universe is created.

The gas has collapsed for millions of years

into the centre of the system

and now, for the first time in cosmic history,

we see the moment of first light -

the moment that the first star formed.

What Volker discovered about these first stars was a revelation.

Big surprise was that the first stars that formed

were very different from stars that form in the present-day universe.

Because these stars were made purely from the primordial gas

with no heavier elements,

they must have been huge.

What we found is that in the early universe,

stars are much more massive -

maybe even 100 times more massive than the sun.

After 100 million years,

this was how the dark ages finally came to an end.

The first stars were giants,

100 times or more the mass of the sun.

That has dramatic consequences,

because massive stars have a very different life -

a much more violent life

than the kind of low mass star that the sun is.

They would be 20 times hotter...

..shining ultraviolet blue...

..10 million times more luminous than the sun.

Although we may never see them for real,

Volker's model has given us an image of these first stars.

The one picture that really captures

this metaphysical moment of first light, it would be like this -

a supercomputer frame that shows the very first star.

It's an image from the childhood of the universe.

An image of the first light from the first ever star.

Let's patch it in just at the end of the cosmic dark ages,

because this is when it happened.

It shows the moment when,

from the impenetrable fog of the dark ages,

light finally dawned on the universe

and of course, it wasn't just one star.

ORCHESTRA TUNES UP

It had been a long time coming,

but after 100 million years of nothing,

the show had finally started.

CONDUCTOR TAPS BATON

ORCHESTRA PLAYS

The dark ages of the universe ended almost abruptly.

It was the same pattern across the universe.

Soon after the first star formed, a few million years later,

another star formed somewhere else and then the process accelerated.

After 100 million years of darkness,

lights were coming on across the universe.

It grew up exponentially.

Very quickly, within tens of millions of years,

there were plenty of stars filling up the universe.

That was the era that so many astronomers had searched for...

..the cosmic dawn.

The cosmic dawn would have been spectacular.

New galaxies were forming out of darkness.

This age of enlightenment was a very dynamic period of time.

And it wasn't just light that was created during the cosmic dawn.

The cosmic dawn is the beginning of complexity in the universe

that led to our existence.

The birth of these great furnaces also triggered

the forging of the more useful ingredients of the universe.

Obviously, I think it's interesting.

For the first time, new elements are being made.

They take hydrogen, turn it into helium.

Helium gets combined to make carbon

and we go to oxygen and silicon.

Deep in their hearts,

the first giant stars began a transformation of matter,

producing the heavy elements necessary for life.

And their huge size had another important consequence.

They burnt through their fuel incredibly quickly.

They can only live for a very short time, only a few million years.

That's really nothing.

You might say they're like the rock stars in the universe.

They live fast and die young.

And so, by the time you make another one over here,

this one may already be ready to die.

When they died, they died in a unique type of supernova -

a hypernova...

..the biggest explosion ever in the universe.

Stars were appearing and disappearing.

It's like fireworks, it's very dynamic.

These were the very first events that spewed out the heavy elements

and led to the formation of the second generation of stars.

And so began the process of stellar recycling,

that after about a thousand generations of birth and death,

led eventually to our own sun being formed.

It had been a long time coming,

but the birth of the first stars

was the catalyst that triggered the transformation of the universe.

For the first time, stars were made,

light was produced

and heavy elements were forged.

And yet, it would still appear an utterly alien universe,

because the dramatic events of the cosmic dawn

were still shrouded behind a veil of fog

and for hundreds of millions of years,

the universe was opaque.

How, then, did our universe go from something so alien and opaque

to what we see today?

It's a transformation that wouldn't be complete while the fog survived.

Those first stars? Very bright.

You know, they could be a million times as bright as our own sun,

giving off tons and tons of light.

But the light's not getting very far yet.

Actually, most of it gets sort of stopped by all this fog of hydrogen.

Atoms of neutral hydrogen still fill the space

between the giant first stars,

so even if we could see that far away,

we might never be able to see them through the fog.

As the light leaves the surface of the star and travels outward,

it gets stopped and so, it couldn't get to us yet,

so the universe at this point is still opaque.

But somehow,

the universe transformed from opaque to transparent.

Tom Abel is trying to work out what happened to the fog.

Like Volker, he uses supercomputer simulation

to try and model these first stars and the fog,

and to work out how the universe became transparent.

What we'd like to do is try and predict the past.

What we have here is one of the first stars forming.

There's a whole filament of gas, that was all that hydrogen gas.

Now see, everything that gets blue here gets really hot.

That's the ultraviolet radiation from this star affecting

everything up to thousands of light years away from that star.

These giants were so hot

that most of the light they gave out was ultraviolet

and it would have had a drastic effect on thick fog.

It's so strong, it can blast the electrons out of the hydrogen atoms.

The radiation that they give off as it's trying to escape

ionises hydrogen gas,

but as a consequence, you actually make things transparent.

Radiation hits the fog,

fog gets transparent.

Now, my boundary to the fog is further away.

Radiation in the next little bit can go a little further,

so I make these bubbles.

Each star created a clearing in the fog around itself,

blowing a bubble of transparent space.

The simplest way to think about it is some Swiss cheese.

As their light travels out, it changes the cheese.

Our air bubbles are growing and we make ever larger ones.

In this way of thinking about it,

at the end, we end up with no cheese at all,

or the bubbles are so big

that the light from those objects really travels freely.

Tom has modelled an entire chunk of the universe,

revealing how it gradually became transparent

during this epoch of re-ionisation.

What we have here is actually the large scale now,

and every little dot that you see in here represents a galaxy

and that galaxy has massive stars inside of it.

They put out ultraviolet radiation

and it makes progressively more of the universe

more and more transparent.

You just look, there are some regions

you can see further and further into the queue

and you see how all these individual bubbles coalesce,

and you get sort of long path lines, like you can see here,

where you can look deep down already and we're not even complete yet.

Some parts of the universe are still neutral and opaque.

But there it goes, and the whole fog lifts

and all the galaxies are revealed.

Re-ionisation would be completed somewhere in these pages.

Tom's models offer an explanation

for how our universe finally became transparent.

Shall we glue it in? Maybe with a light glue?

TOM LAUGHS

In case we have to correct it.

It's the last piece

in our theoretical jigsaw of the cosmic dawn.

After half a billion years,

the universe had gone through an astonishing transformation.

From a dark, featureless sea of fog,

the first stars were born.

They triggered a rollercoaster of creation.

Light was generated,

matter was transformed

and vast bubbles of fog were cleared.

And at the climax of the cosmic dawn,

the curtain was lifted

to reveal a universe that was now transparent.

Finally, here was a universe that we recognise...

..our universe.

At least, that's the theory.

But back in the real world, how can we check?

We can't see the first stars for real.

They're all dead.

And even if we could look back that far,

they'd be hidden in the fog.

However, all is not lost,

because the first stars left behind ghosts -

the bubbles in the fog.

RADIO RETUNES

MUSIC: First Light by Django Django

And these ghosts may offer one last chance

to make contact with the first stars of the cosmic dawn...

RADIO RETUNES

..because the hydrogen fog was transmitting a radio signal.

MUSIC: First Light by My Morning Jacket

# First light tonight

# First light tomorrow

# First light this morning First light this evening

# First light tonight... #

Steven Tingay is trying to tune in to Radio Hydrogen.

In the early universe, in the first billion years,

there were vast amounts of hydrogen

and each one of those hydrogen atoms can randomly give off a radio wave.

And so, we can tune our telescope to that radio frequency

and then, we're tuning in to the hydrogen gas.

# Been looking back

# Down through the ages

# First I was an ancient Then I was an infant

# Now I am alive. #

Trouble is, once the radio waves reach Planet Earth,

that particular band of radio is rather crowded.

Hydrogen gas produces the radio waves at a very specific frequency.

That's similar to sort of FM radio, by the time they get to us.

So it means that we've got to build our telescopes

in areas where there's no human interference,

so you can't have FM radio, you can't have TV.

You can't have mobile phones,

traffic on the road, or anything like that.

# First light this evening First light this morning

# First light tonight. #

It's worth it, because hidden in this radio signal

could be the only message we'll ever get from the cosmic dawn.

Distance is the only cure,

so we need to be in the middle of nowhere, basically.

So, Steven's heading out to Murchison country,

in Western Australia.

It's about the size of the Netherlands,

but with less than 150 residents...

RADIO SIGNAL GOES FUZZY

..and amongst the worst radio, TV and phone reception

anywhere on the planet.

RADIO STATIC

The perfect place for

one of the strangest-looking telescopes you'll ever see.

This is Steven's telescope...

..hundreds of miles from the nearest town.

The Murchison Widefield Array, or MWA.

2,000 antennas spread over more than a square kilometre,

all tuned into the radio signal from the cosmic dawn.

So, what we've got here are the antennas.

We have a cluster of 16 of them here,

so you can build a lot of antennas and get a very sensitive telescope.

Sensitive enough to receive radio waves from the primordial fog

that had been travelling more than 13 billion light years.

And handily for Steven,

the radio waves are only transmitted by the opaque fog,

not by the transparent bubbles.

So, that gas outside the bubble produces the radio waves.

No radio waves from the bubble.

And so, for us, we're sort of looking for this Swiss cheese

pattern of bubbles and holes in the hydrogen gas distribution.

So, although it's not possible to see the first stars,

it should be possible, with this radio set,

to find clues about them

from the way they cleared the hydrogen fog.

We don't actually see the stars themselves.

We see the effect of the star on its environment.

Each atom only emits a tiny signal,

but there was a lot of gas,

and it all adds up to a signal that Steven is close to detecting.

This is an actual image made from the MWA data.

This is a patch of the sky that's around about 30 degrees across,

so it's quite a big chunk of sky.

So, we're looking through our atmosphere,

we're looking through our galaxy,

we're looking through most of the universe.

If you look carefully down here, you can see many, many specks

and these are all galaxies or quasars

millions, billions of light years away,

so we need to remove each of these signals, one by one,

in order to peel back those layers

and hopefully, what we're left with is just the signature of the gas

and the first stars forming, 13 billion years ago.

This signature will be our first direct contact

with the very first stars of the universe.

It will take us right back to the moment of creation

and provide our first glimpse of the cosmic dawn.

It's incredible to think that in this very image,

that I'm looking at right now,

that signal exists.

What's really special for me is being able to look at this

while sort of sitting in an ancient landscape,

where we've actually built the telescope

and collected the data from these signals

that have traversed billions of light years throughout the universe,

so it's just astonishing on a number of different levels for me.

But this is just the beginning.

Once Steven has tuned in to the first stars,

he's going to fill this entire landscape with antennas

to make a much bigger, more precise radio,

that will let him map the early universe as never before.

We want to build a much bigger telescope -

100 times bigger -

and this will dissect the first billion years of the universe,

step by step,

and watch the evolution of the first stars and galaxies

forming in a great deal of detail.

We are all curious where we came from.

If one opens the first chapter of Genesis, in the Bible,

the Old Testament, one finds a version of this story -

how the universe started and how we humans came to live in it.

Some bits of this story are right.

There was a beginning in time.

Light came into existence from darkness.

Life was created.

But other parts of the story are wrong.

Some things are out of context and mixed up

and there are some missing elements.

If I had to give a grade to this early version of the story,

I would give it a B+.

We are now at a special time

that allows us to explore this question scientifically.

We are able to peer deep into space

and see those very early sources of light

that tell us how we came into existence.

And of course, with modern technology,

we are hoping to get the story much more accurate -

to the level of an A+.