All language subtitles for Cosmic Front 03of18 Betelgeuse Death of a Star 710p

The Paranal Observatory in Chile

boasts one of the world's
most beautiful views

of the starry night sky.

It was here in 2009 that a
surprising discovery was made

regarding a particular star.

This star is a 1,000 times
bigger than the Sun,

and is covered in bright red flames.

It also has a bump-like protrusion,

and that's not all.

As I said, I mean it can be very close

to collapse and finally explosion.

It can be even at an age
of 99.9% of its life.

We are in Hida City in Japan.

The star may explode any day now,

and preparing for this is a gigantic

observation device called Super Kamiokande.

It should detect signs of the explosion

faster than anywhere else in the world.

If signs of an explosion are detected,

telescopes around the world
will turn to the star.

The star that's capturing
the attention of the

astronomers worldwide is
the Red Giant in Orion.

Betelgeuse.

It's not the explosion at its death will be

300 million times brighter than the Sun.

Furthermore, it is only
640 light years away.

On the grand scale of the universe,

it's a short distance from Earth.

Some scientists warn the explosion may even

spell danger for Earth.

If it is going to be
produce a Gamma Ray burst

and we're looking straight
down the jet of radiation.

Betelgeuse, the Red Giant.

What is happening now on this star

and what will happen at
the moment of its death.

We investigate Betelgeuse, a
star on the brink of death.

Roppongi, Tokyo.

The city at night,

viewed from the top of a
240-meter high skyscraper.

The city nightscape is not
the only view to be enjoyed.

Guides are on hand to explain
the stars in the night sky.

With the city's bright lights,

it's not easy to find the constellations.

But there is one constellation
that stands out

more than the rest.

Orion.

It's identified by the
three stars in a row,

and the four bright stars surrounding them.

In ancient Greek mythology,

Orion was a brave hunter armed with a club,

who died and ascended
to the heavenly skies.

Today's show features the bright red star

Betelgeuse.

We begin by looking at the
position of each star

that makes up the constellation.

The stars appear to be on the same plane,

but in fact are at widely
varying distances from Earth.

Betelgeuse is 640 light years away,

making it Orion's second
closest star to Earth.

200 years ago, an odd discovery

was made about the star.

It took place on the Cape of Good Hope,

on the southern tip of Africa.

The British established an observatory here

in the 19th century.

At the time, accurate
positioning of the stars

was vital for navigating the seas.

The Observatory was built
to study the stars

visible from the southern hemisphere.

The British astronomer Sir John Herschel

was fascinated by the bright Betelgeuse

and recorded observations of the star.

Herschel noted the stars
in order of brightness,

and noticed something rather strange.

These are the results of
four years of observation.

Orion here refers to Betelgeuse.

In March 1836, Betelgeuse was
the fourth brightest star,

yet eight months later in November,

it was the brightest.

He discovered that sometimes
the star grew dimmer,

and other times brighter.

Why did its brightness vary?

So began the quest to unravel
the mysteries of Betelgeuse.

80 years later in 1920, a
new discovery was made.

This time it was at the
Mount Wilson Observatory

just outside Los Angeles.

The physicist Albert Michelson
thought the varying

brightness of Betelgeuse
was perhaps caused by

changes in its size.

Michelson attached the device
called an interferometer

to the end of a large telescope

and attempted to directly
measure the size of Betelgeuse.

An interferometer uses
two mirrors to reflect

the light from the star,

and then combines the two beams.

When the mirrors are close together,

stripes known as an
interference fringe pattern

appear on the star's image.

As the gap between the mirrors widen,

the stripes gradually fade.

The stripes disappear
completely when the two mirrors

are exactly aligned with the
outer edges of the star.

This distance for Betelgeuse is known,

and so it's possible to
calculate its diameter

from its angular distance at this point.

From these observations,

Michelson concluded that
Betelgeuse was a giant star

300 times larger than the Sun.

But the mystery of its
varying brightness remained.

It was about 40 years later
that the puzzle was solved.

Guy Perrin is researching Betelgeuse

at the Paris Observatory.

Perrin uses results from
the latest observations

to explain the size of
Betelgeuse in the following way:

Detailed observations suggest
Betelgeuse's diameter

could be as wide as 1.4 billion kilometers.

That's 1,000 times greater than the Sun.

Placed at the center of our Solar System,

it would surpass the Earth's orbit,

and reach as far as Jupiter.

What's more, it has changed in size

by more than 100 million kilometers.

The giant star changes its
brightness as it pulsates.

In fact, this pulsation foreshadows
the star's future fate.

Thick stars, which shine
by their own light,

are born and die just like humans.

Stars are born out of clouds
of gas floating in space.

The gas gathers under its own gravity,

and when its core temperature
hits 10 million degrees,

it starts to shine
and a star is born.

A star spins most of its
life shining constantly

in its steady phase.

The Sun is presently in this stage.

But even the Sun will eventually
reach the end of its life,

and gradually expand turning red.

This is when a star becomes a Red Giant.

With a star like Betelgeuse,

whose mass is more than
eight times the Sun,

it expands even further as
it draws nearer to death

and becomes a Red supergiant.

Betelgeuse is coming to
the end of its life.

Scientists around the world
are carrying out research

to reveal the giant star's true shape.

Keiichi Ohnaka is based at the Max Planck

Institute for Radio Astronomy in Germany.

Since moving to Germany in 2000,

he has been studying dying stars.

In 2009, Ohnaka made a surprising discovery

about Betelgeuse's shape.

He made his observations at the

Paranal Observatory in Chile.

At an altitude of 2,600 meters,

and with 350 clear nights per year,

it is the ideal location for
astronomical observation.

This is the Very Large
Telescope Interferometer.

Three telescopes of 1.8 meter aperture

housed in round domes are combined

to make detailed observations.

It works on the same
principle as the device used

by Michelson in 1920, but
it's much more powerful.

The telescopes can be placed
up to 130 meters apart.

Placing the telescopes this
far apart produces images

higher in resolution than ever before.

The images of Betelgeuse
captured by the three telescopes

are laid on top of each other.

A black vertical stripe appears.

This is the interference fringe pattern.

What drew Ohnaka's attention was this part.

There is a kink in the black stripe.

Further investigation revealed
something unexpected.

Normally, spherical stars
produce symmetrical graphs.

In Betelgeuse's case however,

the left side of the graph
is significantly raised.

What can this mean?

Ohnaka grappled with this
conundrum for six months,

and finally reached a conclusion no one

could ever have imagined.

Ohnaka concluded that the
asymmetry in the graph

was caused by a bump
sticking out of Betelgeuse.

Ohnaka explains the star's shape

that he uncovered from
the observation results.

So Betelgeuse is massive, 700
million kilometers wide,

and 40 million times bigger than the Sun.

And unlike normal spherical stars,

it has an irregular shape
because of its bump.

But what caused this huge bump to form?

One scientist is proposing that the answer

lies in the star's interior.

Andrea Chiavassa from the
Free University of Brussels

is using not observations,

but calculations done on
a super computer to try

and decipher the mystery
of Betelgeuse's bump.

He has calculated how he travels out

from the center of the star

and how the gas moves over time.

This is how Betelgeuse looks

according to Chiavassa's calculations.

Its surface is covered in patterns

800 million kilometers wide.

And here and there, pockets of gas rise

and then sink back down.

According to Chiavassa's calculations,

the heat generated inside the star

has created convection currents
hundreds of times wider

than the Sun's diameter.

This is an actual image
of the Sun's surface.

Like Betelgeuse, there
are convection currents.

But they are 800,000 times smaller.

The difference is due to
the internal structure

of the two stars.

In the Sun, convection currents

only occur near the surface.

With Betelgeuse, on the other hand,

the convection currents almost reach the

center of the giant star.

This is why even the convection currents

visible on the surface are so large.

What's more, the currents are moving

at an astounding speed.

According to Chiavassa's calculations,

Betelgeuse's convection currents are rising

at a speed of 30 kilometers per second.

The gravity of the surface is quite low,

as it's so far from the center of the star.

Gas carried up by the convection currents

rising at great speed is
what's creating the bump.

Betelgeuse's odd shape
was caused by the star

expanding with age

and by the shear force of its
massive convection currents.

In 2006, Akari, a Japanese infrared

astronomy satellite was launched.

Using infrared invisible to the naked eye,

it can survey clouds of gas
and dust that float in space.

These are images of
Betelgeuse captured by Akari.

Let's combine these four images

taken with different filters.

This reveals a spherical cloud of gas and

dust enveloping Betelgeuse.

It is three light years wide,

20,000 times greater than
Betelgeuse's diameter.

The huge amount of gas

and dust that can be seen here

is thought to have been
emitted by Betelgeuse.

But it was unknown how Betelgeuse

expelled so much gas and dust.

Trying to decipher this mystery is Perrin

of the Paris Observatory.

Perrin set about observing
the area around Betelgeuse

and the gas it emits.

But it's not an easy task to magnify

and examine the area
surrounding Betelgeuse.

This is because there is turbulence

in the Earth's atmosphere.

When there is turbulence,

the image is distorted making it hard

to accurately capture the gas
and dust that the star emits.

Perrin solved this problem
with a clever idea.

This is a lucky imaging experiment.

This card here will be the star,

and the pool here will be the atmosphere

with random motions that
destroys the image quality.

So we will put the card in the water

and try to take the best image possible.

The technique of lucky
imaging consists in taking

many many pictures until we get

the right picture where the turbulence,

or here the pool is the
most stable possible

so that the image is the best possible.

And we will repeat that for many

many times during the night.

Perrin calls the image
taken the exact moment

there is no turbulence the lucky image.

Let's look at the actual photos taken.

Continuous shots are taken
as a high shutter speed.

In every few hundred photos,

there is one clear image
with no distortion.

This is the lucky image
that Perrin is after.

But in reality, the light
from a star is limited.

To take images at a high shutter speed,

you need a gigantic
telescope that can gather

a large amount of light.

So Perrin headed to the
Paranal Observatory in Chile.

There are some other big
telescopes like these ones,

but this is a unique
place in the sense that

we have four telescopes
in the same Observatory

with a multitude of
instruments that can be used

so that you can make every
observation as you would

think of in modern optical astronomy.

This is the Observatory's

Very Large Telescope or VLT for short.

With mirrors 8.2 meters in diameter,

it's one of the world's largest telescopes.

Using this, it's possible to
capture at high shutter speeds

the faint gas surrounding Betelgeuse.

Perrin checks the images freshly
captured by the telescopes.

The red star that appears on
the screen is Betelgeuse.

So what we see here are

images of Betelgeuse through turbulence.

So this is why they're wobbling.

And sometimes they are much sharper than

some others and that's what
we call lucky imaging.

The star seems to be constantly moving.

Is there a lucky image in there somewhere?

Perrin set the shutter speed
at 7/1000 of a second

and in one night captured over
a million images of the star.

The images were then taken back to the

Paris Observatory for analysis.

Perrin and his team have also
devised a way to pick out

just the lucky images from the
million images of Betelgeuse.

They turn their attention to the

brightest part of the images.

When an image is distorted
by the atmosphere,

light is scattered and the
image is less bright.

So by comparing the brightest
spot of each image

and choosing only the brightest images,

Perrin's team can separate
out all the lucky images.

Furthermore, by combining
all the lucky images,

it's possible to capture even
the faintest, smallest detail.

This is the face of Betelgeuse
that Perrin unmasked

from his million images.

The orange ball is Betelgeuse,

and the blue veil is the
huge quantity of gas

and dust released by the star.

At last, we have an image
that captures the star

expelling gas and dust into space.

Unexpectedly, the gas and
dust are not emitted

in a concentric circle but in
three different directions.

The furthest tip extends four billion

kilometers from the star.

In terms of the Solar System,

this is about the distance
between the Sun and Neptune.

The image also revealed that
a clump of gas and dust

had broken off from the outer edge.

This was how Betelgeuse was
releasing the high volume

of gas and dust that the

infrared satellite Akari had captured.

The red giant with its swelling
bump expels a vast quantity

of gas and dust into the space around it.

The dynamic activity of the
star betrays how close it is

to the end of its life.

The death of Betelgeuse
is drawing ever closer.

What will happen when it dies?

Hans-Thomas Janka has spent
25 years researching

the final years of a star at Germany's

Max Planck Institute for Astrophysics.

Janka uses an experiment to
simulate the death of a star.

We will do a little experiment

of how a supernova works.

How we think a supernova works.

Small container which I will fill

and then we put some water in it.

You see what happens is, of course,

that there's sparkling
bubbles coming and gases.

And then we will see how it evolves.

There's pressure building up,

and in the end we will see whether the lid

stays on this container.

So we see this is the way

how we think explosions work.

Janka believes Betelgeuse
will also be unable

to withstand the immense pressure

and will finally explode.

The massive explosion of a
gigantic star is something the

universe has seen countless
times in its long history.

1987 saw a massive explosion of a star

in a neighboring galaxy,

The Large Magellanic Cloud.

The explosion of the star has
great repercussions for us.

Thick stars like our Sun
emit light as a result of

nuclear fusion taking place in their core.

A star is mostly made up of the

simplest of the elements, Hydrogen.

The high temperature and
pressure inside a star's core

cause Hydrogen to fuse into Helium.

This creates energy making
the star shine brightly.

This is the present state of our Sun.

After a star has shown for
a long period of time,

the Hydrogen in its core
is eventually exhausted.

And then, instead of Hydrogen,

the Helium start fusing with each other.

This produces Carbon, Oxygen,

and other new elements.

The core temperature rises

and the star begins to expand.

And so begins its transformation into

a red giant like Betelgeuse.

Finally, when Iron is created,
the nuclear fusion stops.

The star can no longer support its own mass

and starts to rapidly collapse.

The pressure in the star's
core becomes so immense

it causes a massive explosion.

When the shockwave moves out
of the surface of the star,

we call the phenomenon the Supernova.

Event has observed. We can see this is

spectacularly bright celestial phenomenon.

When a Supernova explodes,

the huge amount of energy generated creates

elements heavier than Iron and
scatters them all around.

The elements created by the
star float abound in space.

Over a long period of time,

elements gradually gather
together once more.

And out of these, planets
like Earth are born.

And furthermore, life in its various forms.

It's all thanks to the
explosion of a dying star

that we are here today.

This is Cassiopeia A, the
remnant of a massive star

that exploded as a Supernova.

It's possible to make out
the various elements

produced by the star.

The red is Iron, and the green is Silicon.

This is another Supernova
remnant, the Crab Nebula.

The cloud of gas and dust is spreading

at a speed of 1,300 kilometers per second.

In this way, elements are scattered

across the universe when stars explode.

In all of recorded history,

only seven Supernova explosions

visible to the naked eye
have been witnessed.

The farthest away was SN 1987A,

a Supernova discovered in 1987

in the large Magellanic Cloud.

It is 160,000 light years away.

The Crab Nebula is the closest to us,

but it's still 6,500
light years from Earth.

In comparison, Betelgeuse is
a mere 640 light years away.

If Betelgeuse becomes a Supernova,

it would be the closest
explosion we have ever faced.

At such a close proximity,

will the Supernova explosion of Betelgeuse

pose any threat to Earth?

Clues to help us answer this question

can be found in Argentina.

It's a two hour drive
from the northern city

of San Juan beyond the ravines.

Geologists from the National
University of Cordoba

in Corboda province guide us to the site.

400 million years ago, dinosaurs
had yet to roam the Earth.

Apart from some moss growing on the ground,

few life forms existed.

Vaccari has found something.

It is a fossil of a Trilobite.

At the time these strata were formed,

the sea was full of many
different organisms

and Trilobites in particular flourished.

There were species that
lived deep in the sea,

and others that lived near the surface.

The sea was full of Trilobites
of all different types.

When Trilobite fossils from different

geological strata are compared,

an interesting fact comes to light.

In strata more than 440 million years old,

both deep sea and shallow
water species are found.

But in strata less than
440 million years old,

only deep water species are found.

One scientist believes
that a Supernova explosion

caused the extinction of the
shallow water Trilobites.

Brian Thomas is an astrophysicist at

Washburn University in America.

At the Ordovician extinction
about 440 million years ago,

the most abundant life was Trilobites.

The main reason for that is
that the Ozone depletion

is a radiation event which
directly affects the organisms.

When a massive star
explodes as a Supernova,

it releases a powerful burst of radiation

in the form of Gamma Rays.

Using theoretical calculations,

Thomas can show what changes
occur to the Earth's

environment when hit by
a burst of Gamma Rays.

This figure here shows the depletion

in Ozone over the globe.

So there's a rapid drop
off in the Ozone layer,

and that reaches about 30-35% total.

And that will increase slowly recovering

over about ten years.

Here is what Thomas thinks happened

to the Trilobites.

Earth is protected from the
Sun's powerful Ultraviolet Rays

by the Ozone layer.

When Gamma Rays produced by a
Supernova explosion hit Earth,

the Ozone layer is destroyed.

This allows the Sun's harmful
rays to beat down on the land

and the surface of the sea.

Thomas believes this killed
off all the Trilobites

near the surface of the
sea, but those deeper down,

where the UV rays couldn't reach, survived.

Once the Ozone is depleted,
Ultraviolet light from the Sun

comes through the atmosphere

and organisms are exposed
to this Ultraviolet light

will have their DNA and other
molecules like proteins

damaged by this particular radiation.

That can cause death.

Thomas argues that the death of a gigantic

star had huge repercussions on life

on Earth in ancient times.

The explosion of Betelgeuse
is thought to be imminent,

but are we in any danger?

Past research has shown
that when a star dies,

powerful Gamma Rays are
released at an angle of

less than two degrees from
the axis of rotation.

So the key lies in the
direction of Betelgeuse's axis

in relation to Earth.

Observations were carried out to measure

Betelgeuse's rotational axis.

The Hubble Space Telescope was used to

investigate the giant star.

It measured the speed
at which certain points

on the star's surface were moving.

This revealed for the first time ever

Betelgeuse's axis of rotation.

The star's axis misses Earth by 20 degrees.

Fortunately, if this is
the pole Betelgeuse,

and it represents the way
the jet would be oriented,

the Earth is not directly
focused along that beam.

It's actually off by about 20 degrees,

so that jet would go off into
space and miss us entirely.

When Betelgeuse explodes,

it looks like Earth will be safe from harm.

What would we be able to see

from Earth when Betelgeuse explodes?

Kenichi Nomoto's team at
the University of Tokyo

has used theory based calculations
to scientifically show

how Betelgeuse will change
in color, temperature,

and shape when it explodes.

Here is a simulation of the results.

The final moments have
arrived for Betelgeuse,

Orion's red super giant.

Its color changes from red to blue

as its temperature shoots up.

One hour later, Betelgeuse
burns more brightly

than any other star

and no one can fail to notice this change.

Three hours after the explosion,

the star's brightness
intensifies until it is around

100 times brighter than the full moon.

Even during the day, it
dazzles in the blue sky.

It is predicted this brightness will

continue for three months.

All around Betelgeuse,
the gas that the star

emits as it dies reflects the intense light

of the Supernova and glows brightly.

Four months later, the star
starts changing color again.

As the temperature falls, it
changes from blue to orange.

The gas swabs the star layer upon layer

like a flower in bloom.

Eventually, as the
temperature drops further,

the star turns red and
then gradually fades.

Four years later, Betelgeuse is no longer

visible to the naked eye.

Orion has finally lost its giant star.

A few hundred years later,

it should be possible to
see the scattered remnants

of Betelgeuse and the nebular of gas

reflecting light in the far distance.

Since the dawn of history,

we have never seen a
Supernova explode so near.

But when will this happen?

In January 2011, an article became a

hot topic of discussion on the internet.

It claimed that Betelgeuse
will explode in 2012.

But no one really knows.

A facility in Japan with the
ability to identify the

explosion before it's visibly observed

is drawing attention from around the world.

It is located 1,000 meters underground

among the mountains of Gifu prefecture.

This is the Super Kamiokande,

an apparatus that detects
particles called Neutrinos

that fly in from space.

Its tank is lined with more
than 10,000 detectors.

Just before a Supernova explodes,

a flood of Neutrinos is
released from the star's core.

The Neutrinos from Betelgeuse
will collide with the water

inside Super Kamiokande's
tank and emit countless

flashes of blue light.

At the earliest, the explosion may happen

just a few hours after these flashes occur.

At the facility, training
is being carried out

to ensure they will detect the explosion.

When a large number of
Neutrinos is detected,

a video conference is held where
scientists around the world

and the data is analyzed.

As soon as the Supernova
explosion is confirmed,

observatories worldwide are notified.

Scientists around the world are
waiting with baited breath

for Betelgeuse to explode.

It's near enough to be a
spectacular spot in the sky

if the Supernova explodes.

We will probably see it during daytime.

It would be fantastic to see that.

To see such a big explosion, very bright.

I would really love to see that
in my lifetime. Absolutely.

Betelgeuse has fascinated us
with its bright red glow.

It is a fierce giant bearing a huge bump

and emitting dust and gas
with staggering force.

And soon it will meet its
death in a massive explosion.

When will its final hour arrive?

At that historic moment,
humankind will witness

yet another undiscovered truth.