Stars...
Burning beacons of light
that dominate the cosmos.
People don't really realize
what sort of monsters
these things are.
Mysterious furnaces
that both create and destroy.
Each individual star
is a fearsome beast
of nuclear energy.
Where did the first stars
come from?
- They would have come - into existence,
they would have burned bright,
and they would have exploded.
And could their explosive deaths
have helped forge
our solar system?
Today, new technology is helping
astronomers unravel the secrets
of the most violent stars
in the universe.
They are a shining light
on how stars live and die...
...unlocking the source
of their power
and revealing
how they shape the cosmos.
...captions by Vitac...
www.Vitac.com
captions paid for by
discovery communications
We live in a universe
teeming with stars.
Using our most powerful
telescopes,
we can see on the order
of 100 billion galaxies.
Each one of those galaxies has
hundreds of billions of stars.
We're talking something like
a sextillion of stars out there.
And that's a number so big
you can't even imagine it.
There are still many mysteries
that we don't yet have answers
for about the nature of stars
and their inner workings
and their deeper history.
Today,
scientists around the world
are working to uncover
the mysteries
of how stars have evolved
to dominate our universe.
Now new technology
is allowing astronomers
to trace their development,
from the very first stars
to exist,
to their explosive deaths...
Their discoveries suggesting
the evolution of extreme stars
may have transformed
our solar system
and played a pivotal role
in our very existence.
One of the key mysteries...
Where did the first-ever stars
come from?
We think that the very
first stars in the universe
were different than the ones
we see around us today.
That first generation of stars
was likely very massive,
very large objects.
What were
these first stars really like?
On mount Graham in Arizona,
star hunter Dan stark
is searching for clues.
Without a doubt,
the formation of the first stars
- and the growth - of the first galaxies
was one of the most important
events in cosmic history.
One of our goals is to be able
to witness the first stars
turning on.
Dan wants to use
the large binocular telescope
to investigate
the early universe
where the first stars
may have emerged.
With two 27-foot mirrors,
this 715-ton rotating structure
is one of the largest optical
telescopes on the planet.
But how can he observe stars
that existed
so far back in time?
One of the great things - about astronomy
- is that we can use - our telescopes
effectively as a time machine.
So, because light travels to us
at a finite speed,
we see the universe
not as it is today,
but as it was when that light
left whatever object
we are looking at.
What you see here
is the Andromeda galaxy.
The Andromeda galaxy is located
2 1/2 million light-years away.
We see this not as it is today,
but as it was
2 1/2 million years ago.
But if we want to study
the first stars,
we need to look at objects that
are a great deal further away.
So we're not just talking
about 2 1/2 million years ago.
We're talking about
over 13 billion years ago.
Today, engineers
are upgrading the telescope.
They are fitting a new detector
called Lucy
that will help Dan
explore the ancient universe.
This primal time
looked very different
to the shining cosmos
that we see today.
13 1/2 billion years ago,
the universe was a fog
of hydrogen and helium gas.
Hidden in this cold darkness,
gravity began to clump
the gas together deep inside.
The gas
became squeezed in the center...
...until the pressure and heat
were so extreme,
it triggered
nuclear reactions...
...and a star was born,
bathing the cosmos in starlight
for the very first time.
Dan has measured the light from
a mysterious faint smudge...
A galaxy called EGS-ZS8-1.
It's one of the oldest galaxies
ever observed.
This little speck
you see here, this galaxy...
The light has been traveling
for more than 13 billion years.
It's located within
the first 700 million years
of the big bang.
But there is
something unusual in Dan's data.
The stars in this galaxy
look different to modern stars,
like our sun
that we see near us today.
We're seeing something
that we don't yet understand.
It looks like these stars
are producing a tremendous
amount of energetic radiation.
It appears
these ancient stars
are not only emitting
visible light,
but extreme
ultraviolet radiation.
You may need very massive
or hot stars
in order to power
the kind of spectral features
that we're seeing.
Could these emissions
hint at what the first stars
in the universe were like?
Scientists think
they were behemoths.
Made from only hydrogen
and helium,
they grew hundreds of times
more massive than the sun.
Their unprecedented size
sent temperatures soaring,
making their surface burn blue.
Blazing over a million times
brighter than the sun,
they may have been the most
radiant stars that ever existed.
To find out if the ancient stars
Dan has detected
could be the first ever formed,
he is measuring
what they are made of.
The only elements to exist
after the big bang
were hydrogen and helium.
Now, if these were truly
the first stars,
we would expect
to just see hydrogen, helium.
We wouldn't expect to see
any trace
of carbon, nitrogen, oxygen...
These heavier chemical elements.
But we found the evidence for
a tremendous amount of carbon
already in place
at these early times.
Finding carbon,
instead of hydrogen and helium,
means the very first stars
must be further back in time,
even closer
to the big bang itself.
- We keep pushing - these cosmic frontiers back,
from a billion years,
to, you know, 500 million years,
to 200 million years
after the big bang.
- As we build - larger and larger telescopes,
we keep looking
further and further back.
And eventually, ultimately,
we'll get back to
this first generation of stars,
first generation of galaxies,
and we'll be able to see these
truly primordial objects emerge.
New technology
will help astronomers like Dan
to, one day, reveal what the
earliest stars were truly like.
What really goes on
inside stars?
What extreme physics
makes them shine?
In Oxfordshire, England,
lies a 200-acre laboratory,
where scientists
are hunting for clues.
Physicist Ian Chapman
has built a star on earth.
It is absolutely remarkable that
mankind is able to do things
as crazy
as put a star here on earth,
which is effectively what we do
every single day of the year.
His star machine is called jet.
Five stories tall
and costing over $1 billion,
it's made
from 38 giant magnetic coils
that surround a center reactor.
Jet is
the biggest fusion reactor
- that we have in the world - at the moment.
It's a huge facility.
- But we need something - on this scale
to produce
the enormous magnetic fields
- which are required - to contain something
which is so energetic
and so hot.
Ian is investigating
where stars
get their energy from
by studying
the extreme nuclear physics
generated inside jet.
Of course, in space,
- we can't see - what's going on inside a star.
The beauty of a laboratory
experiment like this
is that we really can diagnose
in great detail
exactly what's happening.
Can this landmark investigation
reveal what scientists have
tried to prove for centuries?
Can they prove
what powers stars?
3, 2, 1, 0.
In Oxfordshire,
England, Ian Chapman
is investigating the physics
that power stars...
Something scientists have
examined for hundreds of years.
This $1-billion international
research facility is called jet.
And if Chapman's theory
is correct,
it should reveal
how a star like our sun
can produce
such vast amounts of energy.
The sun is an immense ball
of hydrogen and helium.
Above the surface,
a superheated halo
burns at over 2 million degrees.
Beneath this shroud of gas
lies the fiery surface,
emitting 400 trillion trillion
watts of sunlight.
The energy is fueled
from an internal power source...
...310,000 miles
beneath the surface
in the star's mysterious core.
Ian wants to know
how heating hydrogen gas
to extreme temperatures
can generate energy
and reveal
how the sun could be powered.
The reactor must be able
to withstand temperatures
10 times hotter
than the center of the sun.
Engineers use a
manually-controlled robotic arm
to inspect the surfaces
inside the reactor vessel.
So, here we go.
Ian starts the process
by heating the fuel source...
Hydrogen gas.
What we're doing here - is, we'll take some gas,
put it into the vessel,
and then we have to get that gas
really, really hot.
- And so we're passing - an extreme current.
Millions of amps of current
go through that fuel
and turn it into a plasma,
just like you would see
in stars in space.
- So, you have a solid, - then a liquid,
then a gas, then a plasma.
And a plasma
is like a very energetic gas.
The team draws
huge amounts of electricity
to power the 38 magnets.
10, 9, 8, 7...
700 megawatts...
Enough to power an entire city.
...3, 2, 1.
They heat the hydrogen
to 72 million degrees.
The cooler edges of the plasma
begin to glow.
And with a final boost
of energy,
plasma reaches
over 180 million degrees...
So hot, it turns invisible.
Once you have a plasma
- under - that temperature condition,
it behaves in a very similar way
to what happens in the sun.
Scientists believe they can test
how the sun is really powered.
Deep in the heart of the sun...
...the extreme pressure
and temperature
forces hydrogen atoms together,
causing them to fuse
and create helium.
This is nuclear fusion,
and it creates as much energy
as 100 billion atomic bombs
every second.
Gamma rays blast out of the core
and radiate through
the superdense plasma.
The energy transforms
on its journey,
finally reaching the surface,
where it shoots out as light.
At jet,
their results have confirmed
that when hydrogen plasma
reaches 180 million degrees,
a huge amount of energy
is released from nuclear fusion.
This physics is finally
revealing how nuclear fusion
can power stars like our sun.
Fundamentally, - what we're doing here is,
we're understanding where
the stars get their energy from,
why the stars shine,
- why they're giving out - the energy that they are,
because of the fusion
which is going on
inside the body of the star.
But a star's
nuclear fuel won't last forever.
The more massive a star is,
the faster it lives
and the faster it dies.
So really massive stars
have very short lives.
How does a massive
star cataclysmically explode?
Scientists believe
gravity could be to blame.
Throughout its life,
a star is precariously balanced.
Inside,
gravity compresses the star,
pulling it together
while energy blasting
from the core pushes out.
But when the fuel runs out,
gravity wins,
crushing the core
in milliseconds,
and an explosion begins.
But the star's outer layers hide
the fury for up to 10 hours.
It's a giant time bomb.
The star goes supernova...
The greatest explosion
in the cosmos.
To understand the power
in a supernova,
all you have to do
is look at a photograph of one.
So, supernovae
typically occur in galaxies.
So, here's the galaxy
of 100 billion stars.
- And then you have - the one exploding star
that's brighter
than the over 100 billion stars.
Supernovae blow off
these enormous shells of gases
that have these structures
and colors and filaments.
They're just beautiful.
Although we understand
the basic principles
behind the explosions of stars,
the details
are still not understood.
We see
the expanding ejected gases,
and they're really bright.
But this is the aftermath
of the explosion.
So, what about
the explosion itself?
To understand
the mysteries inside supernovae,
scientists hope
to catch one in the act.
Might catastrophically explode?
In the Italian mountains,
physicist Andrea Molinario
is working on a supernova
early-warning system.
Andrea spent his days searching
for strange, elusive particles
called neutrinos.
Hundreds of billions
of neutrino particles
are continually passing through
our bodies unnoticed.
They can even travel
through the entire planet
without being stopped.
To investigate, Andrea travels
to a hidden laboratory
nearly a mile
under the Italian mountains.
Inside the lab
is a machine designed to catch
the mysterious neutrinos,
and it is very large.
The tanks hold 1,100 tons
of liquid packed with sensors
that can pick up
the faint flash of light
and turn it into a signal.
It's so sensitive
to unwanted radiation,
it must be hidden
deep underground.
Andrea thinks that neutrinos
could be the key
to predicting supernovae.
He is looking for a sudden spike
in detections,
a signal
measured only once before.
Hours after a neutrino signal,
a bright light
appeared in the night sky...
A supernova.
Could a burst in neutrinos
be connected
to a stellar explosion?
Scientists believe
that deep inside a dying star...
...the core collapse
turns 99% of the star's energy
into a powerful burst
of neutrinos.
They shoot through the star
at almost the speed of light
and escape into the cosmos.
In their wake,
a shock wave is triggered...
As each layer collapses
and explodes.
In turn, the wave
surges to the edge of the star,
until, hours later,
it finally hits the surface
and explodes in all its glory.
If Andrea picks up
a sudden surge in neutrinos,
the system can issue astronomers
with an alert warning them
that a dying star
could be about to explode.
With a supernova possible
in our galaxy at any time,
the detector
must always be online.
But Andrea isn't the only one
waiting for this burst
of neutrinos.
Around the globe,
from Canada, to the south pole,
there is a network
of similar detectors.
They lay deep underground
or are suspended
within the antarctic ice itself.
Working together, they connect
to the same network...
The supernova early warning
system, or SNEWS.
One day soon,
astronomers will finally be able
to witness
the moment a star explodes.
The earliest moments
of the visible explosion
would be very, very important
for our understanding
of how stars explode.
So, for example,
we don't understand yet
how the implosion of a star
will lead to the explosion,
how the transfer of energy
actually occurs.
If I heard that there's been
a burst of neutrinos
and the neutrino astronomers
are able to tell me where
roughly to point in the sky,
that would be very exciting.
Though a supernova
is a tremendously explosive
and destructive event,
what we've come to learn is,
it's also a central piece
of a great cycle of production.
- Watch out - for rattlesnakes.
New evidence is emerging
that a supernova explosion
could be linked to the formation
of our solar system.
Could a supernova
have even played a part
in our very existence?
Stars...
Extreme nuclear furnaces
shedding light into the cosmos.
But their explosive deaths
play a crucial role
in how the cosmos evolves?
Since the early universe, stars
have been creating chemistry.
People refer to the stars
as the chemical factories
of the universe
because, inside stars,
hydrogen and helium
are being converted
into heavier elements.
So all of the atoms
in my body...
The carbon, nitrogen, calcium,
et cetera...
Is all created inside a star.
Heavy elements
necessary for life
are forged inside stars that
could catastrophically explode.
Looking at these phenomena
is important to us
that eject into the cosmos
the heavy elements.
Could it be
that an exploding star
was critical in the formation
of our own solar system,
and even our own very existence?
In the Arizona desert,
Meenakshi Wadhwa
is hunting for clues
to help solve this mystery.
Watch out
for rattlesnakes.
She is looking for evidence
about our solar system's
formation not in space,
but laying on
the desert floor...
Meteorites.
When we look
at meteorites, when
we study meteorites,
we're really looking back
into the deep past
4 1/2 billion years ago, when
the solar system was forming.
And it was before
even the planets were formed.
Meteorites could be
vital clues fallen from space,
where they started out
as asteroids.
4 1/2 billion years ago,
our solar system
was forming in a spiraling disc.
Deep inside, dust clumped
together, forming rocks.
And collisions
formed our planets.
But some rocks stayed separate
for millions of years.
These asteroids
are time capsules
from the beginning
of the solar system.
Ancient asteroids
could help scientists unlock
the mystery of our sun
and planets' formation
and reveal exploding stars
really were involved.
Most of these objects
are in orbits around the sun,
- and if earth happens - to be just in the right place
or in the wrong place,
they basically fall on the earth
at that time.
So, this is
most definitely not a meteorite.
They're called meteor-wrongs.
What we're really looking for
is something
that looks like this...
A classic meteorite.
It was actually found
very close to this area.
This is
around 4.5 billion years old.
So if there was a supernova
going off nearby,
- there would be some record - of that
in these earliest-formed
objects.
- And so that's part - of what we're looking for
in these rocks
when we study them.
You know, even as a person
who studies these meteorites
for a living,
it's incredible to me
that we actually get
to hold something in our hand
that existed when there
was nothing else around
in our solar system.
- There was - just this cloud of gas and dust
from which things solidified.
And these were
the very first solid objects.
Meenakshi wants to use
meteorites to test one theory.
As our solar system formed,
a supernova blast may have swept
across the cosmos.
This superheated Tsunami
of materials
would have collided
with everything in its path.
The blast mixed debris
into the spiraling disc
and may have deposited
exotic elements among the dust
that began to form
our solar system.
If the theory is true,
Meenakshi should find
a supernova signature
mixed into all the rocks
of the solar system
except for the very oldest.
In the lab, she can see
two different types of material
inside the same meteorite.
Most of the meteorite
is this dark material,
but embedded in it
are these white inclusions.
And these inclusions
are the very first solids
that condensed
from that cloud of gas and dust
as our solar system was forming.
Meenakshi carefully
extracts the inclusions
from the meteorite.
Then she measures
their chemical makeup,
identifying individual atoms.
Her results
show something remarkable.
The chemical signature
of a supernova
appears in the black bulk
of the meteorite,
but not in the white areas...
The oldest parts
called inclusions.
So, the inclusions that we
studied from this meteorite,
they are actually missing
a component
that can only really be injected
by a supernova.
So our solar system
had already started to form
and was basically solidifying
these first solids,
and then the supernova went off
and injected this material
into that forming solar system.
Exotic, heavy elements
from an exploding star
are missing from the oldest
fragments of the solar system,
but they are incorporated
into everything else.
This kind of chemical evidence
is now giving us some proof
that, in fact, there might have
been really a supernova
involved in the formation
of our solar system.
This material goes out.
It's fertile.
It's rich.
And as it cools,
it's ripe for forming stars
and forming planets
and forming life.
So, it's these supernovae, then,
that give rise to the heavy
elements in our bodies...
The carbon in our cells,
the oxygen that we breathe,
the calcium in our bones,
the iron in our red blood cells.
If it were not
for the explosions of stars,
the elements
that are created in stars
would remain locked up
in the core forever.
Since the dawn
of their existence,
stars have been transforming
the chemistry of the universe.
Could it be
that, with each new generation,
the properties
of stars themselves
have been transforming, too?
In Boston, Massachusetts,
astronomer Elisabeth Newton
is investigating
the extreme properties
of some of the smallest stars
in the cosmos.
Hey, John.
Ready to do some observing?
She wants to know if small stars
behave differently
to larger stars, like our sun,
because small stars
are everywhere.
From the earth,
around 9,000 stars are visible
with the naked eye.
Many are yellow, like our sun.
But strip away the dust
of the milky way,
and we would see many more.
1% are blue giants
that live fast and die young.
But hiding amongst them,
more than 3/4 of all stars
are faint red dwarfs,
so dim that from earth they are
invisible to the human eye.
The sun's nearest neighbor
is a red dwarf
only four light-years away.
We just don't see it.
Elisabeth is observing
the behavior
of a particular red dwarf star
called EV Lacertae, or EV Lac.
In 2008, NASA's swift satellite
recorded a massive X-ray flare
from ev lac.
Lasting for eight hours,
it was the brightest
stellar flare ever recorded.
How could a star seemingly
so benign become so violent?
Ev lac,
like many red dwarf stars,
can have very energetic flares.
Even though these stars
are very small,
they can have flares
many times more powerful
than the strongest flares
that we've seen on the sun.
- We've managed to break through - the clouds,
so we have an image
of ev Lacertae now.
And here it is.
- So, this is - our red dwarf star.
It's pretty cool.
Studying the red dwarf,
Elisabeth thinks
its fierce activity
is due to how the star rotates.
In general, if you have
a rapidly-rotating star,
- that star will have - a strong magnetic field.
A slowly-rotating star,
that star will have
a small magnetic field.
And ev lac is in a rapid spin.
The red dwarf is spinning
six time faster than the sun,
creating a powerful
magnetic field.
Deep inside,
a magnetic loop forms
and rises through
the churning plasma.
When the loop
breaks through the surface,
it can become tangled...
And suddenly snap.
It unleashes a mega flare
more powerful
than 100 million atomic bombs.
Red dwarfs, the most common
stars in the universe,
are magnetically active
monsters.
They emit flares that could wipe
out any nearby signs of life.
But they might not
stay this way forever.
You could think - of a red dwarf star as a person.
So, they have this youth
where they're throwing tantrums.
They're this, you know,
very obnoxious child,
and they throw things
everywhere.
So it's like
you're having a 2-year-old
for like 3 billion years.
And then, all of a sudden,
at 3 billion years,
that kid finally begins
to just slow down.
And as they slow down,
their tantrums become less.
They're really
quite well behaved.
The slowing down of red dwarfs
reveal another secret.
Their slow-burning personality
makes them extreme survivors.
The lifetime of a star like
the sun is 10 billion years.
For the red dwarf stars,
- it's about a trillion years - or longer.
These stars
have very long lives.
This new research
is revealing how red dwarfs
evolve from tempestuous beasts
to slow-burning beacons.
Stars can be extreme
in many ways.
To me, there's something
wonderful about the fact
that red dwarfs
are extreme survivors.
These stars will last longer
than any other type of star.
They will be the last stars
that exist in the universe.
But there may be a star killer
hidden in the cosmos...
An extreme star
formed from a supernova
that could cannibalize
red dwarfs.
Since the birth
of the first stars,
our universe has been dominated
by these shining bodies.
Stars are far more than
glimmering lights in the cosmos.
Some people refer to stars
as being the chemists
of the universe.
Amazingly, every single element
besides hydrogen and helium
came from the stars.
When you look
at the universe as a whole,
- you look at galaxies, you look - at stars, you look at people,
what do we all have in common?
We're born, we evolve,
and as we evolve, we change,
and then we die.
But could a star
rise from the dead,
a zombie cannibal that could
feast on other stars?
Near Manchester, England,
Rene Breton
is searching for clues.
He has detected mysterious
radio pulses coming from space.
Initially, - people were really puzzled
because of the repeating nature.
And the very first one to be
discovered was nicknamed lgm1,
which stood for
"little green men, number one,"
- because, to some extent, - you could think,
- "oh, is someone - trying to contact us?
Are there aliens
emitting this signal?"
Rene uses this giant
telescope called Lovell
to investigate the signals.
The Lovell telescope
is the third-biggest
fully-steerable telescope
in the world.
It's got a diameter
of 76 meters,
and so it's possible to detect
extremely faint signal
from the sky.
Rene needs to inspect
the dish for dirt
before he takes any readings.
The telescope is so sensitive,
any buildup on the surface
can affect his data.
If we were to talk
on a mobile phone on Mars,
we could actually pick up
the signal, the conversation,
with the Lovell telescope.
So that's how sensitive it is.
The dish passes the inspection,
and Rene descends
to start his observations.
05-31-31,
and declination
is plus-21-98-2.
Rene steers the telescope
towards the dead remains
of an old exploded star
called the crab nebula.
In this direction, we can hear a
repeating source, it turns out.
We are pointing
towards the crab nebula,
and even though there doesn't
seem to be much in there
except this cloud of gas,
we can actually see in the radio
a source that repeats
33 times per second.
The true nature of these pulses
could be even stranger
than aliens.
Deep inside the crab nebula
lays a cosmic freak.
Formed from the core
of an exploding star,
it weighs more than the sun,
but crushed into the size
of a city.
Its immense gravity comes from
inside the crystal-iron crust,
where a soup of neutrons
is so dense,
a teaspoon
can weigh a billion tons.
It spins 33 times a second,
and beams of radio energy
stream from its magnetic poles.
This freakish star is a pulsar.
Sometimes I say that pulsars
are like zombie stars,
- because they should be - dead stars,
but, actually, they are
still kind of alive in a way.
These hidden zombie
stars lurking in the cosmos
reveal themselves
with their radio pulses,
and they are everywhere.
Rene and his team have detected
hundreds of pulsars,
some of them
spinning at over 42,000 rpm.
The slowest ones may only repeat
once every 10 seconds,
whereas the fastest ones
can go all the way
up to 700 times per second.
But the rotating beam
of one extremely fast pulsar
shows something very unusual.
Pulsars are very stable.
They repeat over and over.
But we see that,
about 15 minutes in,
the pulsar disappears
for a couple of minutes
before reappearing again.
So it's somewhat mysterious.
Something must be maybe
blocking the radio signal.
Looking closer,
Rene has found this pulsar
has a companion...
...a tiny, defenseless star
distorted by gravity
and scorched on one side by
the pulsar's lethal radiation.
The pulsar blasts gas
off the star's surface,
slowly ripping it to pieces.
Caught in a deadly orbit, the
pulsar feasts on the material,
cannibalizing its victim.
But the pulsar is a messy eater,
and the dense cloud of gas
blocks the pulsar's beams,
creating a gap in the pulses
that reach earth...
A giveaway sign
that here lies a monster.
Because
of its extreme dining habits,
this pulsar
has been given a nickname.
We call these systems
black widows,
because a bit like
the black widow spiders,
which, after mating,
basically consumes the male
and gets rid of it
it might be that these systems
actually consume their companion
and completely get rid of them.
And the feasting
of this messy-eating pulsar
is keeping it alive.
This material that falls
onto the surface of the pulsar
spins it up, just a bit like
kids jumping on a merry-go-round
and making it spin
faster and faster.
These black widow systems
are even more extreme zombies
because they really,
literally feed off, you know,
their surrounding in order to,
you know, keep being alive
and spinning
really, really fast.
From the very beginning,
extreme stars have been shaping
our universe.
We have come to know
an amazing amount about stars,
or, you know, stick
a thermometer in them.
But every time
we improve our technology,
we find mysteries and puzzles
that we didn't know were there.
For thousands of years,
- humanity has wanted to think - of the stars
as something different from us.
But the thing that I'm amazed at
is how connected we are
to the stars.
I mean, right here,
pulsing through my veins,
is the story, the drama
of the violent universe.
From the very first
stars in the universe,
extreme stars have been tied
to our very existence.
Furnace that cooks new elements
that are cast out
in cosmic explosions.
This circle of star life
has sculpted
the universe we see today,
where extreme stars will
continue to dominate our cosmos.