Original subtitles

With the Big Bang, 13.7 billion years ago

the Universe was born.

In the beginning the Universe was extremely hot

and filled with light.

But as it rapidly expanded all light was lost.

In the pitch black Universe, only gases floated by,

and not a single shining star was to be seen.

How did this total darkness become the light-filled Universe

that we know today?

So the end of a dark age

occurred when the first fluctuations

the first over-dense regions stopped expanding

and contracted and somehow turned into the first star.

Light was introduced to this dark Universe

for the first time.

This change was brought about by the celestial bodies

known as the first stars.

It's thought that these first stars can be seen 13 billion

light years away.

Now scientists around the world are vying to catch a glimpse

of them.

They were first in the Universe, they were the first

objects in the Universe

and actually their existence changed everything.

What kind of stars were the first ever

stars in the Universe?

What effects did they subsequently have?

These first stars that transformed the dark Universe,

filling it with light.

Cambridge in England is often called the birthplace

of modern science.

It has produced many great thinkers,

such as Darwin, and Newton.

Here one finds another great thinker with a profound

influence on the world today.

Martin Rees is one of the worlds foremost

astrophysicists.

Rees aims to apply theory to unlock the secrets of the

history of the Universe, from it's origin to the present.

I think what is rather wonderful is that

we are able as humans to

make sense of our environment, to understand

how we got here, obviously Darwinian Evolution,

here on our planet, but we are able to put our planet,

the Earth, in this wider cosmic context to trace it right

back to the origin of the solar system,

the origin of the galaxy, and right back to the first

tiny microsecond of the Big Bang

that set everything going.

This is how Rees believes the Universe

came in to being.

It is thought that the Universe began

13.7 billion years ago.

It all began with the Big Bang.

The newly created Universe

started out in a high energy state,

filled with light.

This was the age of light.

Once the Universe had cooled down to

6,000 degrees Celsius, Helium was created;

and at 3,000 degrees, Hydrogen.

Temperatures continued to drop.

The Universe became filled with just Hydrogen and Helium.

As time passed, the visible light that had once filled

the Universe gradually stretched to longer wave lengths

and by around 500,000 years after the Big Bang

there was no light left that could be seen.

This marked the end of the age of light

and the beginning of the dark ages, according to Rees.

Let's turn back the clock from the present to the beginning

of the Universe 13.7 billion years ago.

At some point along the way

all light is lost and darkness envelopes everything.

How long these dark ages lasted and how they ended

remains shrouded in mystery.

One of the things I'm very interested in myself

is how we can actually probe the way

the first light happened in the Universe,

when the first structures formed and lighted up;

were these ordinary stars, were they massive stars,

were they single, were they in groups

and how did those develop into galaxies?

When did the first stars come into being,

shedding light on the dark Universe?

And what kind of stars were they?

Prompted by these questions posed by Rees

astronomers around the world are now attempting

to observe the first stars.

One scientist is trying to observe the first stars directly.

For more than 30 years, Garth Illingworth

of the University of California has been using telescopes

to uncover the origins of the Universe.

It's actually interesting because what we're doing

here is searching for the youngest objects and so

with astronomy and our telescopes what we can do

is look back in time.

To look at the distant Universe

is to look at the past.

Light emitted at a certain moment in the past

travels at the speed of light.

As light travels, time continues to pass.

And so what the observer sees at a distance

is not the present, but in fact the past.

In other words when we see a star that is 10 billion

light years away, we area actually seeing how it looked

10 billion years ago.

It's exciting to be looking out to the

earliest possible times, one of the things that

is behind all of what we do

is trying to understand our place in the Universe.

And so as a person I think I come to this

with a desire to really understand our origins.

Back when Illingworth began his research

the largest telescopes were the ground-based

four meter aperture telescopes.

At the time, he and his colleagues focused on galaxies,

the huge gatherings of stars

to observe the Universe as far away in distance

and therefore in time as possible.

In 1990 this was the most distant galaxy

that could be observed at the time.

Observed at a distance of 7.8 billion light years away

it showed how the galaxy appeared 7.8 billion years ago.

Yet this was still just half of the Universes

13.7 billion year history.

It was around this time that Hubble Space Telescope

was launched.

Hubble was really a game changer

in what it did for astronomy.

Up to that point we had telescopes on the ground that,

while very powerful, were rather limited,

when we looked out through the atmosphere it blurs,

we can't see all different wavelengths,

taking a telescope into space was an amazing change

for us.

Suddenly we had crystal clarity,

there's no atmosphere.

In 2003

Illingworth and his colleagues set out to use

the Hubble Space Telescope to observe the furthest

reaches of the Universe to date.

The target of their observations was one corner of

Fornax in the southern sky.

Using ground based telescopes

this area appears pitch black

with hardly anything visible.

They thought that here they would be able to observe

even dark celestial objects a great distance away.

Hubble made observations of this one region

over the course of 270 hours.

This was the end result.

Ten thousand galaxies of varying sizes

had been captured.

Many galaxies more than ten billion light years away

were also discovered.

The Hubble Space Telescope has allowed humans

to capture with such clarity,

the Universe as it was ten billion years ago.

By looking out even further it may be possible

to observe the first ever stars that ended the dark ages.

With this in mind Illingworth set out to somehow

find a way of observing the most distant celestial objects.

The method he came up with was the layering over

of images.

He layered together 2,062 Hubble images

captured in various observing programs.

In September 2012

an image was produced showing the darkest

celestial object ever captured.

Illingworth proceeded to work out the distance

of each celestial object in the image.

He then singled out a dimly shinning red object.

It is the deepest image of the sky

and so the one that is most exciting

is this one, 6284.

Which is the galaxy that we first found two years ago.

Which is a red shift a little over ten

and then as a result is only 450 million years

from the Big Bang.

The red object shows some spread

and is irregular in shape.

Illingworth believes that this is a galaxy made up of

a billion stars clustered together.

One of the most interesting aspects of this whole

activity of trying to see the earliest galaxies

is trying to understand what came before:

when the first stars and when the first galaxies

formed and started to grow.

And that was probably about 200 million years

before this image.

Thanks to the Hubble Space Telescope

it has been possible to get a glimpse of the

fledgling Universe.

Just 450 million years after the Big Bang.

We are just one step away from finding the first stars

that ended the dark ages.

Looking into the distance

is not the only way of searching for

the first stars.

Rees argues that with some ingenuity

one need not look far to find the first stars.

Rees believes that among the first stars born

more than 13 billion years ago,

a few still survive continuing to shine.

The lifetime of the sun is ten billion years.

A star with a mass 80% of the sun

can continue to shine for well over

13 billion years.

It is therefore entirely possible

that there are first stars still around us.

Further more, Rees explains that the first stars

have a distinctive feature not seen in other stars.

What we don't know

is the masses of these first stars.

We don't know how many there were,

we don't know exactly when they formed.

And that is one of the frontier areas

of our subject at the moment.

But first stars would form from material

made in the Big Bang which contains,

essentially only Hydrogen and Helium.

Immediately after the Big Bang

only two elements, Hydrogen

and Helium, existed in the Universe.

It follows that if a light star made of just these two

elements was discovered,

it would be a first star that has survived to this day.

One scientist is seeking to prove this theory

by seeing if there are any surviving first stars near us.

Anna Frebel has spent the last ten years

searching for a first star

made up of just Hydrogen and Helium.

My research program focuses on finding

the oldest most multipole stars

and of course the ultimate goal is to find

a first star, a star that was...

Came first in the Universe and changed everything.

Born and raised in Germany, Frebel loved stars,

even as a child.

On becoming an astronomer,

she came across the concept of searching for

first stars and has been absorbed by it ever since.

Frebel is currently carrying out observations

at Las Campanas Observatory in Chile.

She is aided in her search for the first stars

by this telescope with its 6.5 meter aperture.

Using special equipment

she analyzes the colors of the stars light

and works out what elements

and how much of them are found in each star.

Can we go to target number

eight please?

This is a star that we observed

earlier tonight and this is one of the most multipole ones

we found that's run.

What you can see is that the lines here

the strong magnesium lines

become much weaker if it was a first star

we would see just continue no lines at all.

But these are pretty weak already

so, we were almost there.

Frebel can only make observations with

this telescope ten days of the year.

To maximize the precocious time she has here

observations are carried out nonstop until dawn.

Frebel has observed 1,500 stars

over the past ten years.

But she has yet to encounter a first star.

If you want to find the needle in the haystack

you have to be very persistent.

We are looking for objects that are very very rare.

So you have to sift through lots and lots and lots of stars,

and hopefully you are lucky in the end.

So you have to be very patient

and very diligent and work very hard

but it's also a lot of fun.

So you have to have fun as well.

Somewhere in this starry sky

a first star is shining, waiting to be found.

It can only be a matter of time,

before it is discovered.

Observational equipment like ground based giant telescopes

and the Hubble Space Telescope are being employed

in the search for the first stars.

The University of Tokyo's, Naoki Yoshida, however,

is approaching the problem with a method

that does not involve making observations.

Yoshida designed a computer simulation

of the newly created Universe,

to observe how the first stars were born.

Just 380,000 years after the Big Bang

intense light was emitted all over the Universe.

By looking 13.7 billion light years away

it should still be possible to observe this light

as microwaves.

In order to observe this light directly

the WMAP's satellite was launched.

The light from 13.7 billion years ago

is observed from all directions in the Universe.

By measuring the differences in the intensity of the light

it is possible to find out how matter was distributed

throughout the Universe at the time.

This is how the primitive Universe looked

at 380,000 years old.

The red spots show regions of low matter density,

while the blue spots indicate high density.

We now know how the Universe looked

13.7 billion years ago, just before the dark ages.

With a starting point established

it's time to turn to Yoshida and his computer.

Working from the WMAP data,

Yoshida used 300 million particles to represent Hydrogen

and Helium and recreated the infant Universe

in his computer.

What looks like smoke are actually particles.

The laws of nature that function between the particles

should remain the same today

as they were 13.7 billion years ago.

Using 107 formulae

including the equations of fluid dynamics

that govern the motion of gas,

Einsteins equations for the expansion of the Universe

and the equations for the chemical reactions

of Hydrogen and Helium,

Yoshida made accurate calculations

of the particles behavior.

This is the young Universe

as recreated by Yoshida's computer.

It shows, for the first time

how the dark ages looked.

The Hydrogen and Helium

that had been drifting about

start becoming uneven in density.

The gasses begin to gather together

under their own gravity

and create a spiderweb like structure.

It took seven years to attain these results.

A spherical mass of gas has been formed,

but no first star yet.

To keep looking beyond this point

calculations within smaller time frames were necessary.

And so three years were spent developing a new model.

To recreate what happened

at the center of the clouds of gas.

These are the results.

The onion like structure shows the density of gas.

The density increases towards the center of the mass.

Here's what happens as time passes.

The density of the gas at the top and bottom

decreases.

Meanwhile, the gas at the sides

does not decrease in density.

The gas flows into the center

and the core becomes increasingly heavy.

The gas continues to be compressed

and when the center reaches a searing temperature

of 100 million degrees Celsius

nuclear fusion begins

and the Universe produces a self illuminating star

for the very first time.

This is the first star.

Yoshida's calculations showed that

many of the first stars were massive stars

that emit an intense blue-white light.

They weigh 50 times the mass of the Sun.

And they are an outstanding million times brighter.

Heavy stars burn up quickly

and so they only live a few million years.

This is the story of the birth of the very first star,

as revealed by Yoshida's computer model.

380,000 years after the big bang

an intense flash of light was emitted all over the Universe.

And then came the dark ages, when darkness reigned.

During this time only Hydrogen and Helium gasses

were present in the Universe.

There was some irregularity in the distribution

of these gasses.

Gas was drawn into the denser regions by gravity

creating a cloud of gas.

The temperature at the center

became increasingly hot.

When it reached 100 million degrees Celsius

nuclear fusion began,

blasting off the surrounding gas.

And so the first star was born.

The temperature of the bright blue surface is

100,000 degrees Celsius.

Its brightness a million times that of the sun.

Emitting vast amounts of energy,

the first star moves ever closer to its dramatic fate.

A few million years have passed since its birth.

The star bursts in a huge explosion

and it comes to the end of its life.

This is the life of the first star

brought to light by the latest astronomical research.

Yoshida's calculations have revealed the spectacular ending

to a first stars life.

The explosion lasts just a moment

but releases such an intense burst of energy

that it may be possible to observe it

even if it happened more than 13 billion light years away.

SWIFT is an astronomy space craft

launched in 2004 to observe massive, explosive phenomena.

When a huge star like a first star explodes

it emits intense electromagnetic waves

called gamma rays.

This phenomena is known as a gamma ray burst.

By detecting the abrupt appearance of gamma rays

SWIFT can seek out the massive explosions of stars.

On April 29th, 2009

SWIFT detected a five second long gamma ray burst

in the constellation Canes Vanetici.

When a massive explosion is detected,

researchers around the world are alerted immediately.

The news sent a ripple of excitement

through astronomers world wide.

Among them was Antonino Cucchiara

who was a student at Pennsylvania State University

at the time.

We needed to act right away.

The main reason for that was we had access to

Hawaiian telescopes

and I was in the east coast and it already was night

so it was sunset in Hawaii,

so the night was just started.

By turning the telescope to the explosion

immediately after its detection

it would be possible to make detailed observations.

At the time, Cucchiara was in Pennsylvania

on the east coast of America.

The telescope was in Hawaii, 8,000 kilometers west,

with a time difference of five hours.

The sun was setting in Hawaii when SWIFT detected

the explosion.

At the Gemini observatory

on the 4,200 meter high summit of Mauna Kea

preparations were underway for scheduled observations.

Astronomer, Kathy Roth

was working in the lab when a Target of Opportunity alarm

flashed up on the computer screen.

Attention, target of opportunity.

So at night when we're observing

if we receive a new rapid T.O.O alert

we interrupt what we're doing, the scheduled observation

so that we can focus on the new T.O.O.

Just like we did back in April 2009.

Roth stopped what she was doing in order

to help with the Target of Opportunity Observation.

Two and a half hours after SWIFT had detected the explosion

a giant eight meter aperture telescope was turned

to its direction.

The observations were carried out for 15 minutes.

But nothing could be seen.

It was this blank image, however,

that excited Cucchiara.

If we don't see anything in your optical images

it's already a sign that this object can really be

one of those most interesting ones.

So it was very exciting, everybody was excited.

Light emanating from the distant Universe

of the first stars has its wavelength stretched

by more than ten times under the influence of

Cosmic Expansion.

This has the effect of changing the light into infrared

waves invisible to the human eye.

In other words, if this were a first star explosion

it wouldn't be visible as ordinary light

but only as infrared.

I think was like 3 a.m in the morning at that point

so it was kind of interesting because at that point

my colleague in Europe and U.K were well awake

so I coordinate with them

we decided to go with another set of observations,

the infrared.

Roth, meanwhile was busy in the control room.

This is the RAW acquisition image in the R-Band

and this is the finding chart.

What you would expect is you would see an object here

which I don't, I don't see anything there,

so we zoom in a little bit to look a little harder,

change its stretch but...

I still don't see anything here.

So then we take an image in the infrared however,

K-Band in this case

then you start to see, there is a faint object there.

If this explosion had occurred more than

13 billion light years away, it's possible it was a star

from more than 13 billion years ago.

In other words, a first star.

To calculate the accurate distance from the exploding star

Cucchiara decided to carry out a third set of observations.

Using equipment that analyzes the colors in light.

But luck was not on their side.

The weather up on the summit,

which had been fine up until then, suddenly turned.

Clouds spread across the sky.

Actually I think it was a phone call from

one of the telescope operators

saying, "I'm sorry but the clouds just roll over"

"and we need to close the dome."

And we were like, ok, I mean we were like...

It was really interesting but

there is some thing we don't have power on.

And that's the weather.

The next day the telescope was turned to

the same spot again.

The light was to faint, however, to carry out the

intended observations.

But Cucchiara did not give up.

Over the course of a year,

he set out trying to work out the distance,

using the infrared images.

When the infrared images were captured

several different filters were used.

At wavelengths any shorter than the filter labeled J,

nothing can be seen.

By analyzing the images captured by Gemini

they could work out the approximate distance from the

celestial object.

The farthest you push an object

in distance, meaning also in time,

is a very close to the beginning of the Big Bang,

you going to start losing information

you start losing light, first you lose the UV light

then the optical and maybe start seeing some

losing light also from the infrared.

And that means also the object is actually high red shift

or means like in this case 500 million years

after the Big Bang.

By observing many more distant explosions

like this, scientists can determine when

and how many, first stars were born.

Martin Rees believes that the appearance of the first stars

transformed the course of history for the Universe.

In order for us to be here, then

lots of things have to have happened over the

13.7 billion years since the Big Bang.

The first stars have to have formed

and they need to have led to nuclear fusion

transmuting primordial Hydrogen and Helium

into elements like Carbon, Oxygen and Iron.

The first stars were born out of just

the Hydrogen and Helium that existed

in the Universe at the time.

Inside the first stars, nuclear fusion took place,

creating elements like Carbon, Nitrogen,

Oxygen and Iron out of the Hydrogen and Helium.

When the first stars meet their demise in an explosion,

these elements are scattered throughout space.

One scientist is making observations of the elements

created by the first stars.

Timothy Beers is searching for the second stars

the second generation stars born just after the first stars

exploded.

Second stars contain elements such as Carbon and Oxygen

that were created by the first stars.

It was thought that the quantity of these elements

would be just one ten-thousandth

of what is found in the Sun.

Beers hopes that by investigating the quantities of elements

found in stars,

he will be able to find the second stars.

In order to make the search more efficient

he employed a special method.

The technique is called Objective Prism.

By placing a giant prism in front of a telescope

the light of each star that had looked like dots

appears as thin bands of rainbow colors.

This is the spectrum created when sunlight

is put through a prism.

A closer look reveals faint black lines

among the rainbow.

These are caused when the elements contained in the sunlight

absorb certain colors of light.

These black lines are known as Absorption Lines.

The Sun produces so many Absorption Lines

because it contains huge amounts of many different elements.

The second stars that Beers is looking for on the other hand

contain hardly any elements apart from Hydrogen

and Helium, which means

there should be very few Absorption Lines.

Beers used two telescopes in Chile and America

to capture a total of 340 photographs.

The glass photographic plates have been carefully stored.

Each glass plate depicts 10,000 stars.

Up close, Absorption Lines can be seen

on most of the stars.

Once we take the plates

with a telescope such as the Burrell Schmidt,

that's really only the beginning of the effort.

We have to find the most interesting

chemically ancient stars.

With that microscope we can determine whether

a star was likely to be interesting or not.

Using this method

this candidate was singled out as a potential second star.

It certainly shows almost no Absorption Lines.

Such candidate stars were then observed through a larger

telescope.

This enabled Beers to pick out 1,044 second stars.

This is a star located in Pisces.

Its iron levels were found to be one ten-thousandth

of those of the Sun,

which allowed Beers to conclude

that it was a second star.

A further investigation threw up a surprise.

The carbon levels were 100 times greater

than what was predicted.

The first stars had produced a great quantity of Carbon;

which had then been passed on to the second stars.

One of the most exciting results of the last

two or three years has been the recognition

that the first stars produce

very large amounts of Carbon, Nitrogen, and Oxygen.

The three fundamental elements without which,

as far as we know, no life can be formed.

The various elements produced by

the first stars are inextricably linked

to the birth of ordinary stars, like our Sun.

This is the theory put forth by one researcher.

John Wise is working on a simulation

of the Universe after the first stars.

Incorporating the elements they produced.

According to Wises simulation

the first stars themselves did not cluster together

to form galaxies.

A few hundred million years after the first stars

were born, galaxies formed where the stars had been.

How were these galaxies created?

Let us study the simulation in more detail.

The top half of the screen shows Wises simulation

of the Universe.

While the bottom half shows the distribution of elements

such as Carbon, Oxygen and Iron at the time.

This is what happens as time progresses.

As the first stars explode,

huge volumes of elements are scattered in certain areas.

A multitude of stars are created where there are high

concentrations of elements,

giving rise to galaxies.

In areas with high levels of Carbon,

Oxygen and Iron,

small stars like the Sun are born one after the other

out of these elements.

Wise believes these were the beginnings of the galaxies

we see today.

These first stars, they produced the very first metals

in the Universe, and without these first metals

we wouldn't see any of the stars that we see today.

The explosions of the first stars changed

the Universe irrevocably.

The explosions caused elements like

Carbon, Oxygen and Iron to scatter all around.

These became the building blocks from which a whole host

of lighter stars like the Sun were born.

These stars clustered together forming galaxies.

In other words, these first stars

paved the way to our present Universe

full of stars and full of life.

The first stars brought light to a dark Universe.

It's thanks to these first stars that the Universe

we know is filled with light and a multitude of elements.

Stars like the Sun and lifeforms like ourselves

can all be traced back to the first stars.

These are the great stars that shaped the

destiny of our Universe.