All language subtitles for How.the.Universe.Works.S07E01.Nightmares.of.Neutron.Stars.1080p.WEB.x264-CAFFEiNE

��

narrator:
Neutron stars.

Super heavy,
super dense.

Narrator: Extreme.

Gravitational,
magnetic, hot.

Narrator: Scary.

Oluseyi:
They destroy planets.

They can even
destroy stars.

Narrator:
A cosmic conundrum.

Tremblay: They're very,
very massive,

but they're also
really, really small.

Narrator:
Tiny cosmic super powers

long overshadowed
by black holes --

until now.

Neutron stars have
been thrust very much

to the forefront of
modern astrophysics.

The world's astronomers know
that something is happening.

Something's up, it's new,
and it's different.

Neutron stars are
the most interesting

astrophysical object
in the universe.

Narrator: Now firmly
in the limelight,

neutron stars, creators of
our most precious elements

and life itself.

-- Captions by vitac --
www.vitac.com

captions paid for by
discovery communications

130 million
light years form earth,

a galaxy called
"ngc-4993."

Two dead stars trapped in
a rapidly diminishing spiral.

It's like listening to the
ringing of the cosmos itself.

The sound of that collision,
if you will,

imprinted on the fabric
of space and time itself.

Narrator: Livingston, Louisiana,
the advanced ligo observatory.

Its mission --
to detect gravitational waves

generated in space.

A gravitational wave is
a distortion of space time

that's caused by,
usually,

some kind of very traumatic
gravitational event.

Narrator:
Events such as a supernova,

or the collision of black holes,
or massive stars.

2015 -- ligo makes history
by detecting gravitational waves

for the first time,

100 years after
Einstein's prediction.

It's the signature of
the crash of black holes.

Tremblay: It's almost like
listening to the sound

of a distant car crash
that you didn't witness.

But you're so clever,

and the sound of this car crash
is such a unique signature,

that you are able to use
your computers to model

exactly the type of cars that
must have collided together.

Narrator: In 2017,
ligo picks up a different

kind of signal.

Oluseyi: The unfolding of
the August 2017 event

was nothing short
of extraordinary.

So, the signal comes in,
and the signal is strange.

It has a
long-lasting signal.

It's over 100 seconds.

Less than two seconds later,
a gamma-ray telescope

detected a flash
of gamma rays

from that same part
of the sky.

And very quickly,
the world's astronomers

know that something
is happening.

Something's up, it's new,
and it's different.

Narrator: This combination of
a long gravitational wave signal

and a Blaze
of gamma rays...

Acts as a beacon
for astronomers.

Sutter:
When they saw this event,

they sent out
a worldwide alert

to astronomers
across the globe, saying,

"hey, we saw
something interesting,

and it came from
a particular patch of sky.

Then, all the
chatter started

amongst the
astronomical community,

and everyone starting
pointing their telescopes

at this one part
of the sky.

Narrator: Within hours,
thousands of astronomers

and physicists across the globe
are frantically

collecting data
on this mysterious event.

Oluseyi: There is not just
the gravitational waves,

there is not just
the gamma rays.

There's a visible light,
there's infrared light,

there's ultraviolet light.

And all these signals together
tell us a story.

And this was
the very first time

we've seen these two
multiple messengers at once --

gravitational waves
and regular light.

So, that was a groundbreaking
moment for astronomy.

Narrator:
Scientists realize

this isn't another
black-hole collision.

This is something
different.

When you see an explosion
in the universe,

there aren't exactly
a lot of candidates.

There's not a lot of things
in the universe that blow up.

Narrator: But the length of
the signal is the smoking gun.

Oluseyi: The collision
of two black holes was quick.

This one was the longer,
slower, death end-spiral

of two neutron stars.

Spiraling in,
closer and closer, speeding up.

And then, when they
finally collide,

when they finally touch,
releasing a tremendous

amount of energy
into the surrounding system.

Narrator: The collision
throws up huge clouds of matter,

which may have slowed down
the light very slightly.

The light
and gravitational waves

travel for
130 million years,

arriving at earth
almost simultaneously.

It's the first time astronomers
see neutron stars collide.

They call it a "kilonova."

And this spectacular
cosmic event

doesn't just
release energy.

The aftermath of this
neutron-star collision,

this kilonova, created
a tremendous amount of debris,

which blasted out
into space.

And this may finally
have provided us

the evidence of where
some very special

heavy elements
are created.

Through the destruction of
a neutron star comes the seeds

for the essential ingredients
of life itself.

We breathe oxygen
molecules -- O2.

Water is
hydrogen and oxygen.

Most of our body is made up
of carbon compounds

that include nitrogen,
phosphorus.

One of the big questions
in science

over the history of humanity
has been,

"what are the origins
of these elements?"

And it turns out that neutron
stars play a critical role

in creating many of
the heavy elements.

Narrator: Most of the elements
on earth are made in stars.

But how the heaviest
elements are made

has been one of science's
longest-running mysteries.

Thaller: For a long time,
we knew there was a problem

with making these
heavier atoms --

things like gold and platinum,
all the way out towards uranium.

And really, the most
energetic thing we had

in the universe
was supernova explosions.

So, they had to be created
somehow in supernovas.

Narrator: But when scientists
ran computer simulations,

virtual supernovas failed to
forge these oversized atoms.

In 2016, astronomer
edo berger explained

a potential solution
to the mystery.

Berger: If you open
any one of these books,

and flip to the page that
tells you where gold came from,

it will tell you that gold
came from supernova explosions.

��

narrator:
But it was becoming clear that
the textbooks were out of date.

��

berger: To form heavy elements
requires a lot of neutrons,

and so, another possible
theory was that

the heaviest elements
were produced in the mergers

of two neutron stars
in a binary system.

Narrator: But at the time,
no one had actually seen

a neutron-star collision.

It was difficult
to convince the community

that this was
a potential channel

for the production
of heavy elements.

The proof is to actually
see this process

happening in the universe.

Narrator:
The 2017 kilonova

provides the
perfect opportunity.

It generates thousands
of hours of data.

Scientists
notice a pattern --

subtle changes in the color
of the kilonova remnants.

Plait: In space, when you have
an event that is very bright,

it emits a certain
amount of light,

and it emits it at
certain wavelengths --

what we think of
as colors.

Narrator: Different colors
in a pyrotechnics display

indicate the use of different
chemicals in fireworks.

In the same way, scientists
can uncover the elements

in the kilonova
by the colors in the explosion.

As the kilonova turns red,
they realize it's the result

of newly-created
heavy elements

starting to absorb
blue light.

As we watched
this remnant change --

the explosion change in
color, expand and cool --

we could estimate what sort of
elements were being produced.

Narrator: The light from
the debris shifts

from blue and Violet
to red and infrared.

The color change
provides clues

about the presence
of certain heavy metals.

��

��

well, this neutron-star
collision, this kilonova,

produced brightness
and a color spectrum

that are consistent
with models of predictions

that produce
gold and platinum.

Narrator: This model
is called "the r-process,"

short for
"rapid neutron capture."

That is a bit of
a complicated term

that describes how we make atoms
heavier than iron.

You need a really
neutron-rich environment.

And as you might imagine,
a neutron-star collision

is a very neutron-rich
environment.

Plait:
If these models are correct --

and this blows me away --

this collision,
this kilonova,

produced several dozen times
the mass of the earth

in just gold.

��

narrator: The 2017 kilonova
not only reveals

the origin
of key elements,

it sheds light on
the neutron star's interior --

the strongest material
in the universe

creating a
magnetic field

a trillion times greater
than that of earth.

Narrator: Two neutron stars
caught in a death spiral.

This massive kilonova explosion
not only sheds light

on the creation
of heavy elements,

such as gold
and platinum,

it also provides scientists
with a unique insight

into one of the most mysterious
objects in the universe.

Trying to imagine what
a neutron star is really like

really challenges
our imagination.

It also challenges
our theoretical physics.

We have to go to our computer
models, our mathematics,

to have some estimate
of what this might be like.

Narrator: Now,
scientists don't have to rely

on their imaginations.

They can use hard data
from the kilonova

to work out what makes
neutron stars tick.

There's so much information
we got from observing

that one single event, that one
colliding neutron star pair.

Now, for the first time,
we have an accurate estimate

of the mass of a neutron star,
and the diameter.

We can finally begin
to piece together

how neutron stars
really work.

Narrator: They calculate
the diameter is just 12.4 miles,

1 mile less than
the length of Manhattan.

Plait: Nailing down
any physical characteristic

is really important.

And if there's
gonna be one,

the radius is a big one,
because from there,

if you know the mass,
you can get the density.

And if you know
the overall density,

you can start to figure out
what the layering

inside of a neutron star
is like.

Narrator: For physicists,
the interior of a neutron star

is one of the most intriguing
places in the universe.

Bullock: You have to realize
that the conditions

inside a neutron star are very,
very different

than the conditions
that exist here on earth.

We're talking about material
that's so dense

that even the nuclei of atoms
can't hold together.

With a neutron star,
you're taking something

that weighs more
than the sun,

and compressing it down
to be smaller than a city.

It's so dense that, if you
tried to put it on the ground,

it would fall
right through the earth.

Narrator: High density
means high gravity --

gravity 200 billion times
greater than on earth.

Imagine climbing up on
a table on the surface

of a neutron star
and jumping off.

You're gonna just
get flattened instantly,

and just spread out
on that surface.

So, don't even think about
trying to do push-ups.

Narrator: Added to
the intense gravity

are hugely powerful
magnetic fields,

awesome X-ray radiation,

electric fields 30 million times
more powerful

than lightning bolts,

and blizzards of
high-energy particles.

This isn't a good neighborhood
for a space traveler.

Sutter: If you were to
find yourself in the vicinity

of a neutron star,
it's gonna be bad news.

First,
you would be torn apart

by the incredibly strong
magnetic fields.

Then, the X-ray radiation
would blast you to a crisp.

And as it
pulled you closer,

its intense gravity
would stretch out

your atoms and molecules
into a long, thin stream.

You would build your speed
faster and faster,

and then, you would finally
impact the surface,

splatter across it.

And that process would
release as much energy

as a nuclear bomb.

If I had the choice between
falling into a neutron star

versus a black hole,
I think I'd pick the black hole.

'Cause I don't really feel like
being torn apart

by a magnetic field
and blasted with x-rays.

Narrator: On a cosmic scale,
neutron stars may be pint-sized,

but they sure pack
a serious punch.

The secret to
all this pent-up power

is what's going on
below the surface.

Armed with
the new kilonova data,

we can now take
a virtual journey

into the heart
of a neutron star.

First, we must pass
through its atmosphere.

Now, it's not like
the earth's atmosphere,

which goes up,
like, a 100 miles.

On a neutron star, the
atmosphere is about this deep,

and it's extremely dense
compared to the air around us.

Narrator:
Below the compressed atmosphere
is a crust of ionized iron,

a mixture of
crystal iron nuclei,

and free-flowing
iron electrons.

Now, the gravity's
so strong

that it's almost
perfectly smooth.

The biggest mountains
on the surface

are gonna be less than
a quarter of an inch high.

Narrator: A quarter-inch
mountain range may sound odd...

But things get even stranger
as we go below the surface.

This is home to the strongest
material in the universe.

It's so weird, scientists
liken it to nuclear pasta.

Sutter: As we dive beneath
the crust of a neutron star,

the neutrons themselves start
to glue themselves together

into exotic shapes.

First, they form clumps that
look something like gnocchi,

then, deeper, the gnocchi
glue themselves together

to form long strands
that look like spaghetti.

Even deeper,
the spaghetti fuse together

to form sheets
of lasagna.

And then, finally,
the lasagna fuse together

to become a uniform mass,
but with holes in it.

So, it looks like penne.

Narrator: This is pasta,
nuclear style,

simmering at a temperature

of over one million
degrees fahrenheit.

Extreme gravity bends,
squeezes, stretches,

and buckles neutrons,
creating a material

100,000 billion times
denser than iron.

But the journey
gets even more extreme.

Even deeper is more mysterious
and harder to understand.

The core of
a neutron star --

which is very far away
from these layers,

which we call
the "nuclear pasta" --

is perhaps the most
exotic form of matter.

So exotic it might be
the last bastion of matter

before complete gravitational
collapse into a black hole.

Narrator: Data from NASA's
chandra observatory

suggests the core
is made up of a super fluid --

a bizarre friction-free
state of matter.

Similar super fluids
produced in the lab

exhibit strange properties,

such as the ability
to flow upwards

and escape
airtight containers.

Although our knowledge
of the star's interior

is still hazy,
there's not mystery

about its dazzling birth.

Forged into life during
the most spectacular event

the universe
has to offer --

the explosive death
of a massive star.

Narrator:
Neutron stars --

Manhattan-sized, but with a mass
twice that of our sun.

So dense a teaspoon of their
matter weighs a billion tons.

Mind-blowing objects
that arrive with a bang.

Tremblay: Neutron stars
spark into life

amid the death
of their parent star.

They're the ultimate story
of resurrection,

or of life from death.

Narrator: It's all part
of a cosmic cycle.

Stars are born from giant
clouds of very cold gas.

Those clouds collapse
under their own gravity,

and the density of the core
at the center of the collapse

starts to increase.

��

narrator: A star is a huge
nuclear fusion reactor.

The force of its gravity
is so powerful

that it fuses
atoms together

to make progressively
heavier and heavier elements.

The star fuses hydrogen
into helium.

Once it exhausts its hydrogen,
then, if it's massive enough,

it can start fusing helium
at its core.

Fusion continues,
forming carbon,

oxygen, nitrogen,
all the way up to iron.

Oluseyi: Once a star
has iron in the core,

it's almost like
you've poisoned it,

because this extinguishes
the nuclear reactions

in the core
of the star.

You fuse something into iron,
and you get no energy.

All of a sudden,
there's nothing to support

the crush of gravity.

No radiation pressure
pushing out

means no pressure keeping the
outer regions from falling in,

and that's what they do.

Narrator: As the star collapses
in its death throes,

its core becomes
the wildest, craziest,

and freakiest pressure cooker
in the whole universe.

The ingredients
are all in place.

It's time to start cooking up
a neutron star.

If we were to scale up
an atomic nucleus

to be the size
of a baseball,

in a normal atom,
the nearest electron would be

way over in those trees,

but in the extreme
conditions that lead to

the formation
of a neutron star,

those electrons can be pushed
closer to the nucleus.

They can come zipping in
from any direction.

And if the temperatures
and pressures are high enough,

they can even
strike the nucleus

and enter it,
and they can hit a proton.

And when they do, they become
converted into more neutrons.

So, in the formation
of one of these objects,

the protons and
electrons disappear,

and you're left with
almost entirely pure neutrons,

with nothing to stop them
from cramming together

and filling up
this entire baseball

with neutrons leading to
incredibly high densities.

Narrator:
With the sea of electrons

now absorbed
in the atomic nuclei,

the matter in the stars can now
press together a lot tighter.

It's like squeezing
300 million tons of mass

into a single sugar cube.

As the star collapses,

enormous amounts of gas
fall towards the core.

The core is small in size,
but huge in mass.

Billions of tons of gas
bounce off of it,

then erupt into
the biggest fireworks display

in the cosmos...

A supernova.

It's massive.

It's bright.

It's imposing.

Supernova are among
the most dramatic events

to happen
in the universe.

A single star dying --

one star dying --
can outshine an entire galaxy.

Narrator: And arising
out of this cataclysm,

a new and very strange
cosmic entity.

Thaller:
When the smoke finally clears
from the supernova explosion,

you're left with one of
the most real, fascinating,

unbelievable monsters
of the entire universe.

Humans have been
witnessing supernovas

for thousands of years,

but we're only now
just starting to understand

what we've truly
been witnessing --

the births
of neutron stars.

Narrator: But while supernovas
are big and bright,

neutron stars are small,

and many don't even
give off light.

So, how many neutron stars
are out there?

We know of about 2,000
neutron stars in our galaxy,

but there probably are many,
many, more.

I'm talking about tens of
millions in the milky way alone,

and certainly billions
throughout the universe.

Narrator:
Neutron stars may be small,
but some give themselves away,

shooting beams
across the universe --

unmistakable, pulsing strobes
of a cosmic lighthouse.

��

narrator: Our knowledge of
neutron stars is expanding fast.

But we didn't even know
they existed

until a lucky discovery
just over 50 years ago.

Sutter: Cambridge,
the mullard radio observatory,

Jocelyn bell,
grad student,

operating the new
radio telescope.

Scanning the sky, doing all
sorts of cool astronomy stuff,

and sees what she calls
"a bit of scruff" in the data.

This scruff is a short

but constantly repeating
burst of radiation

originating 1,000 light years
from earth.

It's so stable and regular
that bell is convinced

there's a fault
with her telescope.

Sutter:
She returns to that spot,

and finds a repeating,
regular signal --

a single point in the sky that
is flashing at us continually,

saying "hi. Hi. Hi."

Blip, blip, blip.

Boom, boom, boom.

Pulse, pulse, pulse.

Nothing that we know of
in the universe,

has such a steady,
perfectly-spaced in time, pulse.

It seemed so perfect that
it must have been artificial.

It looks like
someone is making that,

but it turns out, it's not
a person, but a thing.

What she discovered
was called a "pulsar."

Narrator: A pulsar is
a type of rapidly spinning

neutron star.

Neutron stars had been theorized
in the 1930s,

but were thought to be
too faint to be detected.

Neutron stars were
hypothesized to exist,

but not really
taken seriously.

It was just a,
"oh, that's cute.

Maybe they're out there,
but probably not."

Narrator:
The signal bell detected

seemed like something
from science fiction.

No one had ever seen this
in astronomy before,

and some people even speculated
that it was an alien signal.

She even called them
"lgm objects" --

"little green men."

Narrator: But then,
bell found a second signal.

Little green men
went back to being fiction,

and pulsars became
science fact.

The discovery of pulsars
came out of the blue.

Nobody was expecting this.

So, it was
an amazing breakthrough --

really important.

Narrator: Pulsars pulse
because they are born to spin.

They burst into life
as their parent star collapses

during a supernova.

Any object at all
that is undergoing

any sort of
compression event,

if it has any initial
angular momentum at all,

it will eventually
end up spinning.

Narrator: As the star shrinks,
it spins faster and faster.

They spin so quickly
because the earth-sized core

of a massive star

collapsed to something
as small as a city.

So, because the size of the
object became so much smaller,

the rate of spin had to increase
by a tremendous amount.

Tremblay: Neutron stars can spin
really, really, fast.

Their surface
is moving so fast.

It's moving at about 20% the
speed of light, in some cases.

Sutter: So, if you were to
get on the neutron star ride --

no pregnant women, no bad backs,
no heart issues,

keep your arms and legs
inside the ride at all times,

because they are about
to be obliterated.

Narrator:
And as they spin, they generate
flashing beams of energy.

Tremblay: This beam is like
a lighthouse beam.

You see these periodic flashes
many times per second.

So, every time you see it --

beam, beam, beam.

Narrator: These beams
are the pulsar's calling card.

They're generated
by the elemental chaos

raging inside
a neutron star.

Although the star
is predominantly

a ball of neutrons,

the crust is sprinkled
with protons and electrons,

spinning hundreds
of times a second,

generating an incredible
magnetic field.

And with this strong
magnetic field,

you can create strong
electric fields.

And the electric
and magnetic fields

can work off of each other
and become radiation.

These neutron stars send jets --
beams of radiation --

out of their
spinning poles.

And if their spinning pole
is misaligned,

if they're
a little bit tilted,

this beam will make circles,
across the universe.

And if we're in the path
of one of these circles,

we'll see a flash...

A flash.

Just like if
you're on a ship,

and you observe a distant
lighthouse in a foggy night,

you can see pulsars across
the vast expanse of space

because they are immensely
powerful beams of light.

Narrator: But sometimes,
pulsars get an extra push

that accelerates
the spin even more.

The way you make it spin
even faster

is by subsequently
dumping more material onto it.

That's called "accretion,"
and you end up spinning it up

even faster than it
was already spinning.

Narrator:
Like stellar vampires,

pulsars are ready
to suck the life

out of any objects
that stray too close.

Thaller: Gravity is bringing
that material in,

which means that any spin
it has is accelerated.

It spins faster and faster.

Narrator:
These millisecond pulsars

spin at around
700 revolutions per second.

They are the ultimate
kitchen blender --

they will chop, they will slice,
they will even julienne fry.

Narrator:
So, what stops neutron stars

from simply tearing
themselves apart?

Neutron stars are
incredibly exotic objects

with immense, immense forces
that bind them together,

and so, they can be
held rigid even against

these incredibly fast
rotation speeds.

Bullock: They have
incredibly strong gravity,

and this is what allows them
to hold together

even though they're
spinning around so fast.

Narrator: The speed of the spin
is hard to imagine.

On earth, a day
is 24 hours long.

On a neutron star,
it's a 700th of a second long.

Narrator:
Super-speeding pulsars

are not the only
weird stars

that scientists
are coming to grips with.

There is one other type
of neutron star,

that has the most powerful
magnetic field in the universe.

This magnetic monster
is called a "magnetar."

Narrator: Astronomers monitoring
pulsing neutron stars

have noticed
something very odd.

On very rare occasions,
they can suddenly speed up.

Plait: That's amazing.

I mean, you've got this
incredibly dense object,

and suddenly,
it's spinning faster.

It happens...Instantly.

They'll suddenly
change frequency.

It would take an amazing
amount of power to do that.

What's doing it?

Narrator: These sudden changes
in speed are called "glitches."

One leading idea for
what causes these glitches

is that the core material
latches onto the crust,

and this affects
the way it can spin around.

Narrator:
Excess material beneath
the crust cracks it open,

causing the glitch.

This process releases a
tremendous amount of radiation,

a blast of x-rays, causes
the face of the neutron star

to rearrange itself, and for
the rotation speed to change.

Narrator: But there's another
possible explanation.

Glitches could also be caused
by starquakes.

Sometimes,
the crust gets ruptured.

Anything that basically changes
the geometry of the pulsar

can change the rate
at which it spins.

Narrator: So,
what could be powerful enough

to cause these starquakes?

It's hard to believe

that there's any
force in the universe

that could deform the matter
inside of a neutron star,

which is undergoing
tremendous gravity.

But when it comes to
a neutron star,

if there's one thing that
can do it, it's magnetism.

Narrator:
Extreme magnetic fields

within the star
can get so twisted

they can rip the crust
wide open.

And so, the surface
can restructure itself,

and constantly reshape.

And just a tiny
reconfiguration

of the surface
of a neutron star,

on the order of
a few millimeters,

would be associated with
an enormous release of energy.

Narrator: The neutron star's
immense gravity

smooths over the star's surface
almost instantaneously.

It's like the glitch
never happened.

When it comes
to neutron stars,

there is no end
to magnetic mayhem.

Meet the reigning champion

in the universal "strongest
magnetic field" competition --

the magnetar.

1 in 10 neutron stars
formed during a supernova

becomes a magnetar.

The thing about magnetars,
as is implied in their name --

the magnetic field
on them is so strong,

that even somebody who is
used to using big numbers --

like, say, an astronomer --

is still kind of in awe
of these things.

Narrator:
Magnetars have a magnetic field

one thousand trillion times
stronger than that of earth's.

This amount of magnetism

will seriously mess up
anything that comes close.

Bullock: Any normal object
that we are familiar with,

if it got close to a magnetar,
it would just be shredded.

Any charged particle
with any movement at all,

would just be torn
from its atom.

It would be just
an insane situation.

Narrator:
Magnetars burn brightly,
but their lives are brief.

Tremblay:
We think magnetars --

these intensely
magnetized neutron stars --

can only be
really short-lived.

Their magnetic field
is so powerful

that it should decay
over very rapid time scales,

only on the order of
a few ten thousand years.

Narrator:
It seems their very strength
leads to their downfall.

Plait: That magnetic field
is so strong

that it's picking up material
around it, and accelerating it.

Well, that acts like a drag,
slowing it down.

So, over time, the spin
of the neutron star slows,

and the magnetic field
dies away.

Narrator:
During their lives,

magnetars operate very
differently than pulsars.

They don't have beams.

Their magnetic fields
shoot out gigantic bursts

of high-intensity
radiation.

But recently, astronomers
have spotted one neutron star

that's hard to classify.

It behaves like a stellar
Jekyll and Hyde.

So, this particular neutron star
is a really weird example.

It behaves both like
a radio pulsar,

and also a highly-magnetized
magnetar.

It has the extreme
magnetic fields,

it can have these
magnetic outbursts,

but it also has
this strong jet of radiation

coming out of its poles.

It's almost like it has
a split personality.

Narrator:
When first sighted in 2000,

this star was emitting
radio waves --

typical pulsar behavior.

Then, 16 years later,
it stopped pulsing,

and suddenly started sending out
massive X-ray bursts --

the actions
of a magnetar.

Scientists were baffled.

We don't know if this thing is a
pulsar turning into a magnetar,

or a magnetar turning
into a pulsar.

Narrator: One theory is that
these X-ray bursts happened

because the star's magnetic
field suddenly twisted.

The stress became so great,
the star cracked wide open,

releasing the x-rays
from the fractured crust.

A neutron star
is the densest material

that we know of
in the universe.

And yet, we've seen things

that actually make it shift
and pull apart.

This neutron star is actually
ripping itself apart

under the forces
of the magnetic field.

Narrator:
If this is the case,

placid neutron stars
turn into raging magnetars,

growing old
disgracefully.

When you think about the
life cycle of a human being,

we seem to kind of
slow down over age,

become a little
more calmer.

Neutron stars
do the opposite.

They can be spinning
faster than they were

when they were formed,

and the magnetic field can
get stronger over time.

It's sort of
a reverse aging process.

Narrator: But these strange
changes are extremely rare.

Most pulsars
are as regular as clockwork.

Pulsars are normally
incredibly regular.

You can literally set your watch
to the timing of their pulse.

Narrator: And it's this
stability that we may use

in our future exploration
of the universe.

Plait: You know,
if you're a starship captain,

what you need is
a galactic GPS system.

Well it turns out,
neutron stars may be the answer.

Narrator:
Astronomers often compare

the steady flash of spinning
neutron stars, called "pulsars,"

to cosmic lighthouses.

These flashes are not only
remarkably reliable,

each pulsar has its very own
distinct flickering beam.

Each one has a slightly
different frequency.

Each one has a slightly
different rate.

Anyone in the galaxy,
no matter where you are,

can all agree on the positions
of these pulsars.

Narrator: The unique
signature of pulsars

opens up intriguing
possibilities

for the future
of space travel.

��

straughn: We would
basically be using pulsars

to be able to sort of
triangulate where we're at.

And because those pulses
are so precise,

we can use that in a similar way
that we use GPS satellites

that are stationed
above the earth.

Narrator: Using pulsars
as navigational aids

is not a new idea.

It was recognized
by the NASA voyager mission

in the 1970's.

Affixed to the surface
of those spacecraft

is a golden record.

And on the plate
that covers that record

is a pulsar map,
which in principle could tell

an advanced alien civilization
how to find earth,

because it uses
the position of earth

relative to 14
known pulsars,

as, effectively,
a way to triangulate

the position
of our planet

relative to all
of these pulsars.

Narrator:
Aliens haven't made contact,
but NASA still uses pulsar maps.

NASA recently
launched a satellite

called "nicer sextant"

that exists on the
international space station,

that is being used to test
these types of theories.

��

��

they've used pulsars
to figure out the location

of an object orbiting
around the earth

at 17,000
miles an hour,

and they were able to
pinpoint its location

to within three miles.

That's pretty incredible.

Narrator:
By recognizing their position
relative to known pulsars,

future space missions
could navigate the universe.

��

neutron stars are gonna take us
on this incredible journey --

something as necessary

as knowing where you are
in the galaxy.

We could be many hundreds
of light years away,

but neutron stars
can actually show us

where in the milky way
we are.

��

��

I read a lot of
science fiction,

and I love the idea
of being able to go

from star to star,
planet to planet.

It's kind of weird to think
that, in the future,

as a galactic
coordinate grid,

we might wind up using
these gigantic atomic nuclei,

these rapidly spinning,
bizarrely-constructed,

magnetic, fiercely gravitational
objects like neutron stars.

Narrator: Neutron stars
have come a long way

since being mistaken
for little green men.

Once overlooked
as astronomical oddities,

they've now taken center stage
as genuine stellar superstars.

What's really exciting
about neutron stars is that,

we're at the beginning
of studying them.

We're not at the conclusion.
We've learned a lot,

but there's a lot more
to be learned.

Sutter: From the humble neutron
comes the most powerful,

the most rapid,
the strongest magnetic field,

the most exotic objects
in the cosmos.

Thaller: I love the idea
of a Phoenix,

something actually rising
from its own ashes.

You think something dies,
and that's the end of the story,

but something even
more beautiful,

even more fascinating,
comes afterwards.

I told you at the beginning,
and you didn't believe me,

but now,
I hope you do --

neutron stars
are the most fascinating

astrophysical objects
in the universe.