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��
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narrator:
Neutron stars.
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Super heavy,
super dense.
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Narrator: Extreme.
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Gravitational,
magnetic, hot.
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Narrator: Scary.
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Oluseyi:
They destroy planets.
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They can even
destroy stars.
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Narrator:
A cosmic conundrum.
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Tremblay: They're very,
very massive,
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but they're also
really, really small.
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Narrator:
Tiny cosmic super powers
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long overshadowed
by black holes --
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until now.
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Neutron stars have
been thrust very much
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to the forefront of
modern astrophysics.
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The world's astronomers know
that something is happening.
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Something's up, it's new,
and it's different.
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Neutron stars are
the most interesting
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astrophysical object
in the universe.
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Narrator: Now firmly
in the limelight,
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neutron stars, creators of
our most precious elements
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and life itself.
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-- Captions by vitac --
www.vitac.com
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captions paid for by
discovery communications
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130 million
light years form earth,
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a galaxy called
"ngc-4993."
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Two dead stars trapped in
a rapidly diminishing spiral.
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It's like listening to the
ringing of the cosmos itself.
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The sound of that collision,
if you will,
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imprinted on the fabric
of space and time itself.
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Narrator: Livingston, Louisiana,
the advanced ligo observatory.
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Its mission --
to detect gravitational waves
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generated in space.
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A gravitational wave is
a distortion of space time
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that's caused by,
usually,
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some kind of very traumatic
gravitational event.
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Narrator:
Events such as a supernova,
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or the collision of black holes,
or massive stars.
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2015 -- ligo makes history
by detecting gravitational waves
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for the first time,
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100 years after
Einstein's prediction.
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It's the signature of
the crash of black holes.
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Tremblay: It's almost like
listening to the sound
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of a distant car crash
that you didn't witness.
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But you're so clever,
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and the sound of this car crash
is such a unique signature,
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that you are able to use
your computers to model
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exactly the type of cars that
must have collided together.
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Narrator: In 2017,
ligo picks up a different
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kind of signal.
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Oluseyi: The unfolding of
the August 2017 event
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was nothing short
of extraordinary.
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So, the signal comes in,
and the signal is strange.
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It has a
long-lasting signal.
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It's over 100 seconds.
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Less than two seconds later,
a gamma-ray telescope
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detected a flash
of gamma rays
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from that same part
of the sky.
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And very quickly,
the world's astronomers
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know that something
is happening.
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Something's up, it's new,
and it's different.
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Narrator: This combination of
a long gravitational wave signal
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and a Blaze
of gamma rays...
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Acts as a beacon
for astronomers.
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Sutter:
When they saw this event,
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they sent out
a worldwide alert
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to astronomers
across the globe, saying,
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"hey, we saw
something interesting,
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and it came from
a particular patch of sky.
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Then, all the
chatter started
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amongst the
astronomical community,
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and everyone starting
pointing their telescopes
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at this one part
of the sky.
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Narrator: Within hours,
thousands of astronomers
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and physicists across the globe
are frantically
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collecting data
on this mysterious event.
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Oluseyi: There is not just
the gravitational waves,
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there is not just
the gamma rays.
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There's a visible light,
there's infrared light,
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there's ultraviolet light.
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And all these signals together
tell us a story.
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And this was
the very first time
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we've seen these two
multiple messengers at once --
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gravitational waves
and regular light.
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So, that was a groundbreaking
moment for astronomy.
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Narrator:
Scientists realize
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this isn't another
black-hole collision.
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This is something
different.
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When you see an explosion
in the universe,
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there aren't exactly
a lot of candidates.
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There's not a lot of things
in the universe that blow up.
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Narrator: But the length of
the signal is the smoking gun.
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Oluseyi: The collision
of two black holes was quick.
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This one was the longer,
slower, death end-spiral
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of two neutron stars.
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Spiraling in,
closer and closer, speeding up.
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And then, when they
finally collide,
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when they finally touch,
releasing a tremendous
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amount of energy
into the surrounding system.
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Narrator: The collision
throws up huge clouds of matter,
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which may have slowed down
the light very slightly.
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The light
and gravitational waves
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travel for
130 million years,
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arriving at earth
almost simultaneously.
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It's the first time astronomers
see neutron stars collide.
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They call it a "kilonova."
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And this spectacular
cosmic event
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doesn't just
release energy.
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The aftermath of this
neutron-star collision,
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this kilonova, created
a tremendous amount of debris,
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which blasted out
into space.
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And this may finally
have provided us
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the evidence of where
some very special
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heavy elements
are created.
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Through the destruction of
a neutron star comes the seeds
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for the essential ingredients
of life itself.
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We breathe oxygen
molecules -- O2.
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Water is
hydrogen and oxygen.
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Most of our body is made up
of carbon compounds
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that include nitrogen,
phosphorus.
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One of the big questions
in science
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over the history of humanity
has been,
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"what are the origins
of these elements?"
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And it turns out that neutron
stars play a critical role
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in creating many of
the heavy elements.
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Narrator: Most of the elements
on earth are made in stars.
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But how the heaviest
elements are made
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has been one of science's
longest-running mysteries.
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Thaller: For a long time,
we knew there was a problem
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with making these
heavier atoms --
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things like gold and platinum,
all the way out towards uranium.
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And really, the most
energetic thing we had
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in the universe
was supernova explosions.
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So, they had to be created
somehow in supernovas.
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Narrator: But when scientists
ran computer simulations,
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virtual supernovas failed to
forge these oversized atoms.
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In 2016, astronomer
edo berger explained
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a potential solution
to the mystery.
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Berger: If you open
any one of these books,
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and flip to the page that
tells you where gold came from,
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it will tell you that gold
came from supernova explosions.
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��
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narrator:
But it was becoming clear that
the textbooks were out of date.
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��
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berger: To form heavy elements
requires a lot of neutrons,
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and so, another possible
theory was that
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the heaviest elements
were produced in the mergers
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of two neutron stars
in a binary system.
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Narrator: But at the time,
no one had actually seen
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a neutron-star collision.
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It was difficult
to convince the community
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that this was
a potential channel
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for the production
of heavy elements.
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The proof is to actually
see this process
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happening in the universe.
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Narrator:
The 2017 kilonova
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provides the
perfect opportunity.
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It generates thousands
of hours of data.
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Scientists
notice a pattern --
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subtle changes in the color
of the kilonova remnants.
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Plait: In space, when you have
an event that is very bright,
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it emits a certain
amount of light,
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and it emits it at
certain wavelengths --
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what we think of
as colors.
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Narrator: Different colors
in a pyrotechnics display
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indicate the use of different
chemicals in fireworks.
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In the same way, scientists
can uncover the elements
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in the kilonova
by the colors in the explosion.
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As the kilonova turns red,
they realize it's the result
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of newly-created
heavy elements
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starting to absorb
blue light.
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As we watched
this remnant change --
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the explosion change in
color, expand and cool --
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we could estimate what sort of
elements were being produced.
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Narrator: The light from
the debris shifts
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from blue and Violet
to red and infrared.
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The color change
provides clues
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about the presence
of certain heavy metals.
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��
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��
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well, this neutron-star
collision, this kilonova,
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produced brightness
and a color spectrum
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that are consistent
with models of predictions
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that produce
gold and platinum.
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Narrator: This model
is called "the r-process,"
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short for
"rapid neutron capture."
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That is a bit of
a complicated term
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that describes how we make atoms
heavier than iron.
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You need a really
neutron-rich environment.
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And as you might imagine,
a neutron-star collision
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is a very neutron-rich
environment.
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Plait:
If these models are correct --
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and this blows me away --
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this collision,
this kilonova,
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produced several dozen times
the mass of the earth
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in just gold.
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��
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narrator: The 2017 kilonova
not only reveals
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the origin
of key elements,
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it sheds light on
the neutron star's interior --
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the strongest material
in the universe
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creating a
magnetic field
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a trillion times greater
than that of earth.
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Narrator: Two neutron stars
caught in a death spiral.
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This massive kilonova explosion
not only sheds light
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on the creation
of heavy elements,
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such as gold
and platinum,
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it also provides scientists
with a unique insight
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into one of the most mysterious
objects in the universe.
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Trying to imagine what
a neutron star is really like
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really challenges
our imagination.
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It also challenges
our theoretical physics.
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We have to go to our computer
models, our mathematics,
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to have some estimate
of what this might be like.
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Narrator: Now,
scientists don't have to rely
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00:12:00,520 --> 00:12:01,853
on their imaginations.
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They can use hard data
from the kilonova
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to work out what makes
neutron stars tick.
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There's so much information
we got from observing
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that one single event, that one
colliding neutron star pair.
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Now, for the first time,
we have an accurate estimate
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of the mass of a neutron star,
and the diameter.
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We can finally begin
to piece together
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how neutron stars
really work.
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Narrator: They calculate
the diameter is just 12.4 miles,
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1 mile less than
the length of Manhattan.
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Plait: Nailing down
any physical characteristic
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is really important.
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And if there's
gonna be one,
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the radius is a big one,
because from there,
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if you know the mass,
you can get the density.
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And if you know
the overall density,
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you can start to figure out
what the layering
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inside of a neutron star
is like.
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Narrator: For physicists,
the interior of a neutron star
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is one of the most intriguing
places in the universe.
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Bullock: You have to realize
that the conditions
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inside a neutron star are very,
very different
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00:13:09,722 --> 00:13:11,789
than the conditions
that exist here on earth.
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We're talking about material
that's so dense
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that even the nuclei of atoms
can't hold together.
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With a neutron star,
you're taking something
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that weighs more
than the sun,
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and compressing it down
to be smaller than a city.
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It's so dense that, if you
tried to put it on the ground,
247
00:13:28,341 --> 00:13:30,208
it would fall
right through the earth.
248
00:13:32,211 --> 00:13:35,279
Narrator: High density
means high gravity --
249
00:13:35,281 --> 00:13:40,084
gravity 200 billion times
greater than on earth.
250
00:13:40,086 --> 00:13:41,685
Imagine climbing up on
a table on the surface
251
00:13:41,687 --> 00:13:43,554
of a neutron star
and jumping off.
252
00:13:43,556 --> 00:13:45,689
You're gonna just
get flattened instantly,
253
00:13:45,691 --> 00:13:48,291
and just spread out
on that surface.
254
00:13:48,293 --> 00:13:52,696
So, don't even think about
trying to do push-ups.
255
00:13:52,698 --> 00:13:54,498
Narrator: Added to
the intense gravity
256
00:13:54,500 --> 00:13:57,234
are hugely powerful
magnetic fields,
257
00:13:57,236 --> 00:13:59,303
awesome X-ray radiation,
258
00:13:59,305 --> 00:14:02,974
electric fields 30 million times
more powerful
259
00:14:02,976 --> 00:14:04,976
than lightning bolts,
260
00:14:04,978 --> 00:14:09,112
and blizzards of
high-energy particles.
261
00:14:09,114 --> 00:14:13,084
This isn't a good neighborhood
for a space traveler.
262
00:14:16,055 --> 00:14:19,056
Sutter: If you were to
find yourself in the vicinity
263
00:14:19,058 --> 00:14:22,593
of a neutron star,
it's gonna be bad news.
264
00:14:22,595 --> 00:14:24,595
First,
you would be torn apart
265
00:14:24,597 --> 00:14:27,264
by the incredibly strong
magnetic fields.
266
00:14:27,266 --> 00:14:32,204
Then, the X-ray radiation
would blast you to a crisp.
267
00:14:32,206 --> 00:14:34,070
And as it
pulled you closer,
268
00:14:34,072 --> 00:14:36,473
its intense gravity
would stretch out
269
00:14:36,475 --> 00:14:40,010
your atoms and molecules
into a long, thin stream.
270
00:14:40,012 --> 00:14:42,947
You would build your speed
faster and faster,
271
00:14:42,949 --> 00:14:45,950
and then, you would finally
impact the surface,
272
00:14:45,952 --> 00:14:47,686
splatter across it.
273
00:14:47,688 --> 00:14:50,755
And that process would
release as much energy
274
00:14:50,757 --> 00:14:51,822
as a nuclear bomb.
275
00:14:54,894 --> 00:14:58,095
If I had the choice between
falling into a neutron star
276
00:14:58,097 --> 00:15:01,298
versus a black hole,
I think I'd pick the black hole.
277
00:15:01,300 --> 00:15:03,501
'Cause I don't really feel like
being torn apart
278
00:15:03,503 --> 00:15:06,036
by a magnetic field
and blasted with x-rays.
279
00:15:10,509 --> 00:15:15,045
Narrator: On a cosmic scale,
neutron stars may be pint-sized,
280
00:15:15,047 --> 00:15:17,715
but they sure pack
a serious punch.
281
00:15:17,717 --> 00:15:20,317
The secret to
all this pent-up power
282
00:15:20,319 --> 00:15:24,855
is what's going on
below the surface.
283
00:15:24,857 --> 00:15:27,391
Armed with
the new kilonova data,
284
00:15:27,393 --> 00:15:29,126
we can now take
a virtual journey
285
00:15:29,128 --> 00:15:31,795
into the heart
of a neutron star.
286
00:15:31,797 --> 00:15:36,133
First, we must pass
through its atmosphere.
287
00:15:36,135 --> 00:15:37,467
Now, it's not like
the earth's atmosphere,
288
00:15:37,469 --> 00:15:39,269
which goes up,
like, a 100 miles.
289
00:15:39,271 --> 00:15:42,673
On a neutron star, the
atmosphere is about this deep,
290
00:15:42,675 --> 00:15:47,945
and it's extremely dense
compared to the air around us.
291
00:15:47,947 --> 00:15:52,549
Narrator:
Below the compressed atmosphere
is a crust of ionized iron,
292
00:15:52,551 --> 00:15:54,951
a mixture of
crystal iron nuclei,
293
00:15:54,953 --> 00:15:58,289
and free-flowing
iron electrons.
294
00:15:58,291 --> 00:16:00,357
Now, the gravity's
so strong
295
00:16:00,359 --> 00:16:02,560
that it's almost
perfectly smooth.
296
00:16:02,562 --> 00:16:04,028
The biggest mountains
on the surface
297
00:16:04,030 --> 00:16:06,431
are gonna be less than
a quarter of an inch high.
298
00:16:06,433 --> 00:16:11,902
Narrator: A quarter-inch
mountain range may sound odd...
299
00:16:11,904 --> 00:16:16,207
But things get even stranger
as we go below the surface.
300
00:16:18,311 --> 00:16:22,279
This is home to the strongest
material in the universe.
301
00:16:25,451 --> 00:16:31,522
It's so weird, scientists
liken it to nuclear pasta.
302
00:16:31,524 --> 00:16:34,525
Sutter: As we dive beneath
the crust of a neutron star,
303
00:16:34,527 --> 00:16:37,861
the neutrons themselves start
to glue themselves together
304
00:16:37,863 --> 00:16:39,730
into exotic shapes.
305
00:16:39,732 --> 00:16:45,002
First, they form clumps that
look something like gnocchi,
306
00:16:45,004 --> 00:16:48,072
then, deeper, the gnocchi
glue themselves together
307
00:16:48,074 --> 00:16:52,142
to form long strands
that look like spaghetti.
308
00:16:52,144 --> 00:16:54,678
Even deeper,
the spaghetti fuse together
309
00:16:54,680 --> 00:16:58,148
to form sheets
of lasagna.
310
00:16:58,150 --> 00:17:01,151
And then, finally,
the lasagna fuse together
311
00:17:01,153 --> 00:17:05,689
to become a uniform mass,
but with holes in it.
312
00:17:05,691 --> 00:17:08,159
So, it looks like penne.
313
00:17:08,161 --> 00:17:11,629
Narrator: This is pasta,
nuclear style,
314
00:17:11,631 --> 00:17:12,829
simmering at a temperature
315
00:17:12,831 --> 00:17:15,632
of over one million
degrees fahrenheit.
316
00:17:15,634 --> 00:17:19,436
Extreme gravity bends,
squeezes, stretches,
317
00:17:19,438 --> 00:17:22,372
and buckles neutrons,
creating a material
318
00:17:22,374 --> 00:17:26,710
100,000 billion times
denser than iron.
319
00:17:26,712 --> 00:17:30,447
But the journey
gets even more extreme.
320
00:17:30,449 --> 00:17:34,251
Even deeper is more mysterious
and harder to understand.
321
00:17:34,253 --> 00:17:36,320
The core of
a neutron star --
322
00:17:36,322 --> 00:17:39,123
which is very far away
from these layers,
323
00:17:39,125 --> 00:17:41,191
which we call
the "nuclear pasta" --
324
00:17:41,193 --> 00:17:44,395
is perhaps the most
exotic form of matter.
325
00:17:44,397 --> 00:17:48,665
So exotic it might be
the last bastion of matter
326
00:17:48,667 --> 00:17:52,937
before complete gravitational
collapse into a black hole.
327
00:17:54,941 --> 00:17:57,274
Narrator: Data from NASA's
chandra observatory
328
00:17:57,276 --> 00:18:00,678
suggests the core
is made up of a super fluid --
329
00:18:00,680 --> 00:18:04,414
a bizarre friction-free
state of matter.
330
00:18:04,416 --> 00:18:07,151
Similar super fluids
produced in the lab
331
00:18:07,153 --> 00:18:09,086
exhibit strange properties,
332
00:18:09,088 --> 00:18:11,822
such as the ability
to flow upwards
333
00:18:11,824 --> 00:18:15,693
and escape
airtight containers.
334
00:18:15,695 --> 00:18:18,028
Although our knowledge
of the star's interior
335
00:18:18,030 --> 00:18:20,230
is still hazy,
there's not mystery
336
00:18:20,232 --> 00:18:22,432
about its dazzling birth.
337
00:18:22,434 --> 00:18:26,503
Forged into life during
the most spectacular event
338
00:18:26,505 --> 00:18:28,505
the universe
has to offer --
339
00:18:28,507 --> 00:18:31,910
the explosive death
of a massive star.
340
00:18:48,127 --> 00:18:50,127
Narrator:
Neutron stars --
341
00:18:50,129 --> 00:18:56,800
Manhattan-sized, but with a mass
twice that of our sun.
342
00:18:56,802 --> 00:19:02,806
So dense a teaspoon of their
matter weighs a billion tons.
343
00:19:02,808 --> 00:19:07,077
Mind-blowing objects
that arrive with a bang.
344
00:19:07,079 --> 00:19:09,013
Tremblay: Neutron stars
spark into life
345
00:19:09,015 --> 00:19:11,081
amid the death
of their parent star.
346
00:19:11,083 --> 00:19:13,684
They're the ultimate story
of resurrection,
347
00:19:13,686 --> 00:19:16,353
or of life from death.
348
00:19:16,355 --> 00:19:20,490
Narrator: It's all part
of a cosmic cycle.
349
00:19:20,492 --> 00:19:24,762
Stars are born from giant
clouds of very cold gas.
350
00:19:24,764 --> 00:19:27,866
Those clouds collapse
under their own gravity,
351
00:19:27,868 --> 00:19:31,034
and the density of the core
at the center of the collapse
352
00:19:31,036 --> 00:19:32,169
starts to increase.
353
00:19:32,171 --> 00:19:37,307
��
354
00:19:37,309 --> 00:19:41,178
narrator: A star is a huge
nuclear fusion reactor.
355
00:19:41,180 --> 00:19:43,780
The force of its gravity
is so powerful
356
00:19:43,782 --> 00:19:45,582
that it fuses
atoms together
357
00:19:45,584 --> 00:19:50,454
to make progressively
heavier and heavier elements.
358
00:19:50,456 --> 00:19:53,657
The star fuses hydrogen
into helium.
359
00:19:53,659 --> 00:19:56,860
Once it exhausts its hydrogen,
then, if it's massive enough,
360
00:19:56,862 --> 00:19:59,196
it can start fusing helium
at its core.
361
00:20:01,734 --> 00:20:04,401
Fusion continues,
forming carbon,
362
00:20:04,403 --> 00:20:10,474
oxygen, nitrogen,
all the way up to iron.
363
00:20:10,476 --> 00:20:12,743
Oluseyi: Once a star
has iron in the core,
364
00:20:12,745 --> 00:20:14,678
it's almost like
you've poisoned it,
365
00:20:14,680 --> 00:20:18,414
because this extinguishes
the nuclear reactions
366
00:20:18,416 --> 00:20:19,749
in the core
of the star.
367
00:20:19,751 --> 00:20:23,954
You fuse something into iron,
and you get no energy.
368
00:20:23,956 --> 00:20:25,756
All of a sudden,
there's nothing to support
369
00:20:25,758 --> 00:20:27,091
the crush of gravity.
370
00:20:27,093 --> 00:20:28,759
No radiation pressure
pushing out
371
00:20:28,761 --> 00:20:32,697
means no pressure keeping the
outer regions from falling in,
372
00:20:32,699 --> 00:20:34,565
and that's what they do.
373
00:20:34,567 --> 00:20:37,767
Narrator: As the star collapses
in its death throes,
374
00:20:37,769 --> 00:20:41,171
its core becomes
the wildest, craziest,
375
00:20:41,173 --> 00:20:45,375
and freakiest pressure cooker
in the whole universe.
376
00:20:47,513 --> 00:20:50,046
The ingredients
are all in place.
377
00:20:50,048 --> 00:20:54,853
It's time to start cooking up
a neutron star.
378
00:20:54,855 --> 00:20:57,654
If we were to scale up
an atomic nucleus
379
00:20:57,656 --> 00:20:59,522
to be the size
of a baseball,
380
00:20:59,524 --> 00:21:03,594
in a normal atom,
the nearest electron would be
381
00:21:03,596 --> 00:21:05,530
way over in those trees,
382
00:21:05,532 --> 00:21:07,664
but in the extreme
conditions that lead to
383
00:21:07,666 --> 00:21:09,867
the formation
of a neutron star,
384
00:21:09,869 --> 00:21:13,937
those electrons can be pushed
closer to the nucleus.
385
00:21:13,939 --> 00:21:17,073
They can come zipping in
from any direction.
386
00:21:17,075 --> 00:21:19,943
And if the temperatures
and pressures are high enough,
387
00:21:19,945 --> 00:21:22,012
they can even
strike the nucleus
388
00:21:22,014 --> 00:21:24,881
and enter it,
and they can hit a proton.
389
00:21:24,883 --> 00:21:29,419
And when they do, they become
converted into more neutrons.
390
00:21:29,421 --> 00:21:32,023
So, in the formation
of one of these objects,
391
00:21:32,025 --> 00:21:34,424
the protons and
electrons disappear,
392
00:21:34,426 --> 00:21:37,360
and you're left with
almost entirely pure neutrons,
393
00:21:37,362 --> 00:21:40,430
with nothing to stop them
from cramming together
394
00:21:40,432 --> 00:21:43,300
and filling up
this entire baseball
395
00:21:43,302 --> 00:21:48,905
with neutrons leading to
incredibly high densities.
396
00:21:48,907 --> 00:21:50,307
Narrator:
With the sea of electrons
397
00:21:50,309 --> 00:21:52,776
now absorbed
in the atomic nuclei,
398
00:21:52,778 --> 00:21:57,714
the matter in the stars can now
press together a lot tighter.
399
00:21:57,716 --> 00:22:00,917
It's like squeezing
300 million tons of mass
400
00:22:00,919 --> 00:22:04,254
into a single sugar cube.
401
00:22:04,256 --> 00:22:06,056
As the star collapses,
402
00:22:06,058 --> 00:22:09,126
enormous amounts of gas
fall towards the core.
403
00:22:11,863 --> 00:22:16,399
The core is small in size,
but huge in mass.
404
00:22:16,401 --> 00:22:19,203
Billions of tons of gas
bounce off of it,
405
00:22:19,205 --> 00:22:22,672
then erupt into
the biggest fireworks display
406
00:22:22,674 --> 00:22:25,542
in the cosmos...
407
00:22:25,544 --> 00:22:28,145
A supernova.
408
00:22:28,147 --> 00:22:29,412
It's massive.
409
00:22:29,414 --> 00:22:30,546
It's bright.
410
00:22:30,548 --> 00:22:31,815
It's imposing.
411
00:22:31,817 --> 00:22:34,951
Supernova are among
the most dramatic events
412
00:22:34,953 --> 00:22:36,419
to happen
in the universe.
413
00:22:36,421 --> 00:22:38,088
A single star dying --
414
00:22:38,090 --> 00:22:43,061
one star dying --
can outshine an entire galaxy.
415
00:22:46,965 --> 00:22:49,432
Narrator: And arising
out of this cataclysm,
416
00:22:49,434 --> 00:22:52,836
a new and very strange
cosmic entity.
417
00:22:55,841 --> 00:22:58,775
Thaller:
When the smoke finally clears
from the supernova explosion,
418
00:22:58,777 --> 00:23:01,445
you're left with one of
the most real, fascinating,
419
00:23:01,447 --> 00:23:04,580
unbelievable monsters
of the entire universe.
420
00:23:04,582 --> 00:23:06,183
Humans have been
witnessing supernovas
421
00:23:06,185 --> 00:23:07,851
for thousands of years,
422
00:23:07,853 --> 00:23:10,654
but we're only now
just starting to understand
423
00:23:10,656 --> 00:23:13,457
what we've truly
been witnessing --
424
00:23:13,459 --> 00:23:17,327
the births
of neutron stars.
425
00:23:17,329 --> 00:23:20,463
Narrator: But while supernovas
are big and bright,
426
00:23:20,465 --> 00:23:23,066
neutron stars are small,
427
00:23:23,068 --> 00:23:26,202
and many don't even
give off light.
428
00:23:26,204 --> 00:23:30,141
So, how many neutron stars
are out there?
429
00:23:30,143 --> 00:23:33,677
We know of about 2,000
neutron stars in our galaxy,
430
00:23:33,679 --> 00:23:35,279
but there probably are many,
many, more.
431
00:23:35,281 --> 00:23:38,148
I'm talking about tens of
millions in the milky way alone,
432
00:23:38,150 --> 00:23:42,419
and certainly billions
throughout the universe.
433
00:23:42,421 --> 00:23:48,291
Narrator:
Neutron stars may be small,
but some give themselves away,
434
00:23:48,293 --> 00:23:51,762
shooting beams
across the universe --
435
00:23:51,764 --> 00:23:56,967
unmistakable, pulsing strobes
of a cosmic lighthouse.
436
00:24:10,315 --> 00:24:13,251
��
437
00:24:16,054 --> 00:24:20,524
narrator: Our knowledge of
neutron stars is expanding fast.
438
00:24:23,128 --> 00:24:25,263
But we didn't even know
they existed
439
00:24:25,265 --> 00:24:28,765
until a lucky discovery
just over 50 years ago.
440
00:24:30,803 --> 00:24:34,003
Sutter: Cambridge,
the mullard radio observatory,
441
00:24:34,005 --> 00:24:35,939
Jocelyn bell,
grad student,
442
00:24:35,941 --> 00:24:39,475
operating the new
radio telescope.
443
00:24:39,477 --> 00:24:42,612
Scanning the sky, doing all
sorts of cool astronomy stuff,
444
00:24:42,614 --> 00:24:48,017
and sees what she calls
"a bit of scruff" in the data.
445
00:24:48,019 --> 00:24:49,419
This scruff is a short
446
00:24:49,421 --> 00:24:52,756
but constantly repeating
burst of radiation
447
00:24:52,758 --> 00:24:57,027
originating 1,000 light years
from earth.
448
00:24:57,029 --> 00:25:00,296
It's so stable and regular
that bell is convinced
449
00:25:00,298 --> 00:25:02,900
there's a fault
with her telescope.
450
00:25:02,902 --> 00:25:04,901
Sutter:
She returns to that spot,
451
00:25:04,903 --> 00:25:09,106
and finds a repeating,
regular signal --
452
00:25:09,108 --> 00:25:14,710
a single point in the sky that
is flashing at us continually,
453
00:25:14,712 --> 00:25:17,514
saying "hi. Hi. Hi."
454
00:25:17,516 --> 00:25:19,182
Blip, blip, blip.
455
00:25:19,184 --> 00:25:21,518
Boom, boom, boom.
456
00:25:21,520 --> 00:25:23,453
Pulse, pulse, pulse.
457
00:25:23,455 --> 00:25:25,455
Nothing that we know of
in the universe,
458
00:25:25,457 --> 00:25:30,059
has such a steady,
perfectly-spaced in time, pulse.
459
00:25:30,061 --> 00:25:34,265
It seemed so perfect that
it must have been artificial.
460
00:25:34,267 --> 00:25:37,734
It looks like
someone is making that,
461
00:25:37,736 --> 00:25:41,671
but it turns out, it's not
a person, but a thing.
462
00:25:41,673 --> 00:25:44,475
What she discovered
was called a "pulsar."
463
00:25:47,346 --> 00:25:50,013
Narrator: A pulsar is
a type of rapidly spinning
464
00:25:50,015 --> 00:25:51,281
neutron star.
465
00:25:54,086 --> 00:25:57,954
Neutron stars had been theorized
in the 1930s,
466
00:25:57,956 --> 00:26:01,892
but were thought to be
too faint to be detected.
467
00:26:01,894 --> 00:26:06,429
Neutron stars were
hypothesized to exist,
468
00:26:06,431 --> 00:26:09,365
but not really
taken seriously.
469
00:26:09,367 --> 00:26:11,902
It was just a,
"oh, that's cute.
470
00:26:11,904 --> 00:26:14,404
Maybe they're out there,
but probably not."
471
00:26:15,641 --> 00:26:17,440
Narrator:
The signal bell detected
472
00:26:17,442 --> 00:26:21,445
seemed like something
from science fiction.
473
00:26:21,447 --> 00:26:24,180
No one had ever seen this
in astronomy before,
474
00:26:24,182 --> 00:26:28,319
and some people even speculated
that it was an alien signal.
475
00:26:28,321 --> 00:26:30,720
She even called them
"lgm objects" --
476
00:26:30,722 --> 00:26:33,590
"little green men."
477
00:26:33,592 --> 00:26:36,093
Narrator: But then,
bell found a second signal.
478
00:26:38,931 --> 00:26:42,132
Little green men
went back to being fiction,
479
00:26:42,134 --> 00:26:45,868
and pulsars became
science fact.
480
00:26:45,870 --> 00:26:48,137
The discovery of pulsars
came out of the blue.
481
00:26:48,139 --> 00:26:49,739
Nobody was expecting this.
482
00:26:49,741 --> 00:26:51,876
So, it was
an amazing breakthrough --
483
00:26:51,878 --> 00:26:53,076
really important.
484
00:26:56,348 --> 00:27:00,750
Narrator: Pulsars pulse
because they are born to spin.
485
00:27:00,752 --> 00:27:04,821
They burst into life
as their parent star collapses
486
00:27:04,823 --> 00:27:06,356
during a supernova.
487
00:27:08,627 --> 00:27:10,961
Any object at all
that is undergoing
488
00:27:10,963 --> 00:27:13,095
any sort of
compression event,
489
00:27:13,097 --> 00:27:16,299
if it has any initial
angular momentum at all,
490
00:27:16,301 --> 00:27:20,503
it will eventually
end up spinning.
491
00:27:20,505 --> 00:27:24,508
Narrator: As the star shrinks,
it spins faster and faster.
492
00:27:26,511 --> 00:27:30,647
They spin so quickly
because the earth-sized core
493
00:27:30,649 --> 00:27:32,048
of a massive star
494
00:27:32,050 --> 00:27:35,252
collapsed to something
as small as a city.
495
00:27:35,254 --> 00:27:39,456
So, because the size of the
object became so much smaller,
496
00:27:39,458 --> 00:27:44,127
the rate of spin had to increase
by a tremendous amount.
497
00:27:44,129 --> 00:27:47,464
Tremblay: Neutron stars can spin
really, really, fast.
498
00:27:47,466 --> 00:27:49,932
Their surface
is moving so fast.
499
00:27:49,934 --> 00:27:53,670
It's moving at about 20% the
speed of light, in some cases.
500
00:27:53,672 --> 00:27:57,006
Sutter: So, if you were to
get on the neutron star ride --
501
00:27:57,008 --> 00:28:01,077
no pregnant women, no bad backs,
no heart issues,
502
00:28:01,079 --> 00:28:03,680
keep your arms and legs
inside the ride at all times,
503
00:28:03,682 --> 00:28:05,950
because they are about
to be obliterated.
504
00:28:07,886 --> 00:28:13,223
Narrator:
And as they spin, they generate
flashing beams of energy.
505
00:28:13,225 --> 00:28:15,625
Tremblay: This beam is like
a lighthouse beam.
506
00:28:15,627 --> 00:28:18,962
You see these periodic flashes
many times per second.
507
00:28:18,964 --> 00:28:20,563
So, every time you see it --
508
00:28:20,565 --> 00:28:23,834
beam, beam, beam.
509
00:28:23,836 --> 00:28:26,903
Narrator: These beams
are the pulsar's calling card.
510
00:28:26,905 --> 00:28:29,639
They're generated
by the elemental chaos
511
00:28:29,641 --> 00:28:32,241
raging inside
a neutron star.
512
00:28:32,243 --> 00:28:34,110
Although the star
is predominantly
513
00:28:34,112 --> 00:28:35,978
a ball of neutrons,
514
00:28:35,980 --> 00:28:39,716
the crust is sprinkled
with protons and electrons,
515
00:28:39,718 --> 00:28:41,918
spinning hundreds
of times a second,
516
00:28:41,920 --> 00:28:44,621
generating an incredible
magnetic field.
517
00:28:46,391 --> 00:28:48,191
And with this strong
magnetic field,
518
00:28:48,193 --> 00:28:50,260
you can create strong
electric fields.
519
00:28:50,262 --> 00:28:51,994
And the electric
and magnetic fields
520
00:28:51,996 --> 00:28:55,665
can work off of each other
and become radiation.
521
00:28:55,667 --> 00:29:01,337
These neutron stars send jets --
beams of radiation --
522
00:29:01,339 --> 00:29:03,406
out of their
spinning poles.
523
00:29:03,408 --> 00:29:05,942
And if their spinning pole
is misaligned,
524
00:29:05,944 --> 00:29:07,545
if they're
a little bit tilted,
525
00:29:07,547 --> 00:29:11,815
this beam will make circles,
across the universe.
526
00:29:11,817 --> 00:29:14,550
And if we're in the path
of one of these circles,
527
00:29:14,552 --> 00:29:17,086
we'll see a flash...
528
00:29:17,088 --> 00:29:18,287
A flash.
529
00:29:18,289 --> 00:29:19,889
Just like if
you're on a ship,
530
00:29:19,891 --> 00:29:22,559
and you observe a distant
lighthouse in a foggy night,
531
00:29:22,561 --> 00:29:26,630
you can see pulsars across
the vast expanse of space
532
00:29:26,632 --> 00:29:30,166
because they are immensely
powerful beams of light.
533
00:29:30,168 --> 00:29:33,570
Narrator: But sometimes,
pulsars get an extra push
534
00:29:33,572 --> 00:29:37,240
that accelerates
the spin even more.
535
00:29:37,242 --> 00:29:39,376
The way you make it spin
even faster
536
00:29:39,378 --> 00:29:42,578
is by subsequently
dumping more material onto it.
537
00:29:42,580 --> 00:29:45,114
That's called "accretion,"
and you end up spinning it up
538
00:29:45,116 --> 00:29:47,183
even faster than it
was already spinning.
539
00:29:47,185 --> 00:29:49,252
Narrator:
Like stellar vampires,
540
00:29:49,254 --> 00:29:51,589
pulsars are ready
to suck the life
541
00:29:51,591 --> 00:29:54,958
out of any objects
that stray too close.
542
00:29:54,960 --> 00:29:57,393
Thaller: Gravity is bringing
that material in,
543
00:29:57,395 --> 00:30:00,129
which means that any spin
it has is accelerated.
544
00:30:00,131 --> 00:30:01,998
It spins faster and faster.
545
00:30:02,000 --> 00:30:04,200
Narrator:
These millisecond pulsars
546
00:30:04,202 --> 00:30:08,471
spin at around
700 revolutions per second.
547
00:30:08,473 --> 00:30:10,541
They are the ultimate
kitchen blender --
548
00:30:10,543 --> 00:30:14,844
they will chop, they will slice,
they will even julienne fry.
549
00:30:17,549 --> 00:30:19,616
Narrator:
So, what stops neutron stars
550
00:30:19,618 --> 00:30:22,752
from simply tearing
themselves apart?
551
00:30:22,754 --> 00:30:26,156
Neutron stars are
incredibly exotic objects
552
00:30:26,158 --> 00:30:30,093
with immense, immense forces
that bind them together,
553
00:30:30,095 --> 00:30:32,361
and so, they can be
held rigid even against
554
00:30:32,363 --> 00:30:34,631
these incredibly fast
rotation speeds.
555
00:30:38,369 --> 00:30:40,236
Bullock: They have
incredibly strong gravity,
556
00:30:40,238 --> 00:30:42,172
and this is what allows them
to hold together
557
00:30:42,174 --> 00:30:44,241
even though they're
spinning around so fast.
558
00:30:47,312 --> 00:30:52,715
Narrator: The speed of the spin
is hard to imagine.
559
00:30:52,717 --> 00:30:54,917
On earth, a day
is 24 hours long.
560
00:30:54,919 --> 00:30:59,922
On a neutron star,
it's a 700th of a second long.
561
00:30:59,924 --> 00:31:01,591
Narrator:
Super-speeding pulsars
562
00:31:01,593 --> 00:31:03,859
are not the only
weird stars
563
00:31:03,861 --> 00:31:06,395
that scientists
are coming to grips with.
564
00:31:06,397 --> 00:31:08,798
There is one other type
of neutron star,
565
00:31:08,800 --> 00:31:12,735
that has the most powerful
magnetic field in the universe.
566
00:31:12,737 --> 00:31:17,040
This magnetic monster
is called a "magnetar."
567
00:31:32,490 --> 00:31:35,692
Narrator: Astronomers monitoring
pulsing neutron stars
568
00:31:35,694 --> 00:31:38,561
have noticed
something very odd.
569
00:31:38,563 --> 00:31:44,233
On very rare occasions,
they can suddenly speed up.
570
00:31:44,235 --> 00:31:45,435
Plait: That's amazing.
571
00:31:45,437 --> 00:31:47,437
I mean, you've got this
incredibly dense object,
572
00:31:47,439 --> 00:31:48,839
and suddenly,
it's spinning faster.
573
00:31:48,841 --> 00:31:50,973
It happens...Instantly.
574
00:31:50,975 --> 00:31:52,775
They'll suddenly
change frequency.
575
00:31:52,777 --> 00:31:56,112
It would take an amazing
amount of power to do that.
576
00:31:56,114 --> 00:31:57,714
What's doing it?
577
00:31:57,716 --> 00:32:02,318
Narrator: These sudden changes
in speed are called "glitches."
578
00:32:02,320 --> 00:32:04,654
One leading idea for
what causes these glitches
579
00:32:04,656 --> 00:32:07,257
is that the core material
latches onto the crust,
580
00:32:07,259 --> 00:32:10,460
and this affects
the way it can spin around.
581
00:32:10,462 --> 00:32:14,397
Narrator:
Excess material beneath
the crust cracks it open,
582
00:32:14,399 --> 00:32:16,399
causing the glitch.
583
00:32:16,401 --> 00:32:20,336
This process releases a
tremendous amount of radiation,
584
00:32:20,338 --> 00:32:24,874
a blast of x-rays, causes
the face of the neutron star
585
00:32:24,876 --> 00:32:29,212
to rearrange itself, and for
the rotation speed to change.
586
00:32:29,214 --> 00:32:31,881
Narrator: But there's another
possible explanation.
587
00:32:31,883 --> 00:32:36,152
Glitches could also be caused
by starquakes.
588
00:32:36,154 --> 00:32:38,688
Sometimes,
the crust gets ruptured.
589
00:32:38,690 --> 00:32:42,825
Anything that basically changes
the geometry of the pulsar
590
00:32:42,827 --> 00:32:45,695
can change the rate
at which it spins.
591
00:32:45,697 --> 00:32:47,230
Narrator: So,
what could be powerful enough
592
00:32:47,232 --> 00:32:50,633
to cause these starquakes?
593
00:32:50,635 --> 00:32:51,634
It's hard to believe
594
00:32:51,636 --> 00:32:54,037
that there's any
force in the universe
595
00:32:54,039 --> 00:32:57,106
that could deform the matter
inside of a neutron star,
596
00:32:57,108 --> 00:32:59,842
which is undergoing
tremendous gravity.
597
00:32:59,844 --> 00:33:01,444
But when it comes to
a neutron star,
598
00:33:01,446 --> 00:33:04,647
if there's one thing that
can do it, it's magnetism.
599
00:33:04,649 --> 00:33:06,382
Narrator:
Extreme magnetic fields
600
00:33:06,384 --> 00:33:09,185
within the star
can get so twisted
601
00:33:09,187 --> 00:33:11,921
they can rip the crust
wide open.
602
00:33:11,923 --> 00:33:14,591
And so, the surface
can restructure itself,
603
00:33:14,593 --> 00:33:16,125
and constantly reshape.
604
00:33:16,127 --> 00:33:18,794
And just a tiny
reconfiguration
605
00:33:18,796 --> 00:33:20,564
of the surface
of a neutron star,
606
00:33:20,566 --> 00:33:22,198
on the order of
a few millimeters,
607
00:33:22,200 --> 00:33:26,736
would be associated with
an enormous release of energy.
608
00:33:26,738 --> 00:33:28,805
Narrator: The neutron star's
immense gravity
609
00:33:28,807 --> 00:33:34,009
smooths over the star's surface
almost instantaneously.
610
00:33:34,011 --> 00:33:36,480
It's like the glitch
never happened.
611
00:33:40,017 --> 00:33:42,084
When it comes
to neutron stars,
612
00:33:42,086 --> 00:33:46,756
there is no end
to magnetic mayhem.
613
00:33:46,758 --> 00:33:48,691
Meet the reigning champion
614
00:33:48,693 --> 00:33:53,228
in the universal "strongest
magnetic field" competition --
615
00:33:53,230 --> 00:33:55,764
the magnetar.
616
00:33:55,766 --> 00:33:59,302
1 in 10 neutron stars
formed during a supernova
617
00:33:59,304 --> 00:34:01,771
becomes a magnetar.
618
00:34:01,773 --> 00:34:06,376
The thing about magnetars,
as is implied in their name --
619
00:34:06,378 --> 00:34:08,578
the magnetic field
on them is so strong,
620
00:34:08,580 --> 00:34:11,114
that even somebody who is
used to using big numbers --
621
00:34:11,116 --> 00:34:12,915
like, say, an astronomer --
622
00:34:12,917 --> 00:34:15,985
is still kind of in awe
of these things.
623
00:34:15,987 --> 00:34:18,321
Narrator:
Magnetars have a magnetic field
624
00:34:18,323 --> 00:34:22,525
one thousand trillion times
stronger than that of earth's.
625
00:34:22,527 --> 00:34:24,460
This amount of magnetism
626
00:34:24,462 --> 00:34:29,332
will seriously mess up
anything that comes close.
627
00:34:29,334 --> 00:34:31,800
Bullock: Any normal object
that we are familiar with,
628
00:34:31,802 --> 00:34:35,471
if it got close to a magnetar,
it would just be shredded.
629
00:34:35,473 --> 00:34:37,674
Any charged particle
with any movement at all,
630
00:34:37,676 --> 00:34:39,609
would just be torn
from its atom.
631
00:34:39,611 --> 00:34:42,945
It would be just
an insane situation.
632
00:34:42,947 --> 00:34:47,350
Narrator:
Magnetars burn brightly,
but their lives are brief.
633
00:34:47,352 --> 00:34:48,685
Tremblay:
We think magnetars --
634
00:34:48,687 --> 00:34:51,287
these intensely
magnetized neutron stars --
635
00:34:51,289 --> 00:34:53,156
can only be
really short-lived.
636
00:34:53,158 --> 00:34:55,425
Their magnetic field
is so powerful
637
00:34:55,427 --> 00:34:57,961
that it should decay
over very rapid time scales,
638
00:34:57,963 --> 00:35:00,630
only on the order of
a few ten thousand years.
639
00:35:00,632 --> 00:35:04,967
Narrator:
It seems their very strength
leads to their downfall.
640
00:35:04,969 --> 00:35:06,970
Plait: That magnetic field
is so strong
641
00:35:06,972 --> 00:35:09,972
that it's picking up material
around it, and accelerating it.
642
00:35:09,974 --> 00:35:12,041
Well, that acts like a drag,
slowing it down.
643
00:35:12,043 --> 00:35:15,177
So, over time, the spin
of the neutron star slows,
644
00:35:15,179 --> 00:35:16,946
and the magnetic field
dies away.
645
00:35:19,250 --> 00:35:20,583
Narrator:
During their lives,
646
00:35:20,585 --> 00:35:24,186
magnetars operate very
differently than pulsars.
647
00:35:24,188 --> 00:35:25,854
They don't have beams.
648
00:35:25,856 --> 00:35:28,858
Their magnetic fields
shoot out gigantic bursts
649
00:35:28,860 --> 00:35:32,261
of high-intensity
radiation.
650
00:35:32,263 --> 00:35:35,932
But recently, astronomers
have spotted one neutron star
651
00:35:35,934 --> 00:35:38,468
that's hard to classify.
652
00:35:38,470 --> 00:35:42,639
It behaves like a stellar
Jekyll and Hyde.
653
00:35:44,743 --> 00:35:48,544
So, this particular neutron star
is a really weird example.
654
00:35:48,546 --> 00:35:51,013
It behaves both like
a radio pulsar,
655
00:35:51,015 --> 00:35:53,950
and also a highly-magnetized
magnetar.
656
00:35:53,952 --> 00:35:56,219
It has the extreme
magnetic fields,
657
00:35:56,221 --> 00:35:59,021
it can have these
magnetic outbursts,
658
00:35:59,023 --> 00:36:01,691
but it also has
this strong jet of radiation
659
00:36:01,693 --> 00:36:02,892
coming out of its poles.
660
00:36:02,894 --> 00:36:07,029
It's almost like it has
a split personality.
661
00:36:07,031 --> 00:36:09,298
Narrator:
When first sighted in 2000,
662
00:36:09,300 --> 00:36:11,767
this star was emitting
radio waves --
663
00:36:11,769 --> 00:36:14,703
typical pulsar behavior.
664
00:36:14,705 --> 00:36:18,707
Then, 16 years later,
it stopped pulsing,
665
00:36:18,709 --> 00:36:23,179
and suddenly started sending out
massive X-ray bursts --
666
00:36:23,181 --> 00:36:26,115
the actions
of a magnetar.
667
00:36:26,117 --> 00:36:29,118
Scientists were baffled.
668
00:36:29,120 --> 00:36:32,321
We don't know if this thing is a
pulsar turning into a magnetar,
669
00:36:32,323 --> 00:36:34,924
or a magnetar turning
into a pulsar.
670
00:36:34,926 --> 00:36:37,860
Narrator: One theory is that
these X-ray bursts happened
671
00:36:37,862 --> 00:36:41,930
because the star's magnetic
field suddenly twisted.
672
00:36:41,932 --> 00:36:46,402
The stress became so great,
the star cracked wide open,
673
00:36:46,404 --> 00:36:50,406
releasing the x-rays
from the fractured crust.
674
00:36:50,408 --> 00:36:52,675
A neutron star
is the densest material
675
00:36:52,677 --> 00:36:54,543
that we know of
in the universe.
676
00:36:54,545 --> 00:36:55,811
And yet, we've seen things
677
00:36:55,813 --> 00:36:58,281
that actually make it shift
and pull apart.
678
00:36:58,283 --> 00:37:00,883
This neutron star is actually
ripping itself apart
679
00:37:00,885 --> 00:37:02,885
under the forces
of the magnetic field.
680
00:37:02,887 --> 00:37:04,420
Narrator:
If this is the case,
681
00:37:04,422 --> 00:37:08,891
placid neutron stars
turn into raging magnetars,
682
00:37:08,893 --> 00:37:12,428
growing old
disgracefully.
683
00:37:12,430 --> 00:37:14,364
When you think about the
life cycle of a human being,
684
00:37:14,366 --> 00:37:16,299
we seem to kind of
slow down over age,
685
00:37:16,301 --> 00:37:17,767
become a little
more calmer.
686
00:37:17,769 --> 00:37:19,368
Neutron stars
do the opposite.
687
00:37:19,370 --> 00:37:21,237
They can be spinning
faster than they were
688
00:37:21,239 --> 00:37:22,504
when they were formed,
689
00:37:22,506 --> 00:37:24,774
and the magnetic field can
get stronger over time.
690
00:37:24,776 --> 00:37:28,045
It's sort of
a reverse aging process.
691
00:37:28,047 --> 00:37:31,248
Narrator: But these strange
changes are extremely rare.
692
00:37:31,250 --> 00:37:36,319
Most pulsars
are as regular as clockwork.
693
00:37:36,321 --> 00:37:38,254
Pulsars are normally
incredibly regular.
694
00:37:38,256 --> 00:37:41,524
You can literally set your watch
to the timing of their pulse.
695
00:37:41,526 --> 00:37:43,993
Narrator: And it's this
stability that we may use
696
00:37:43,995 --> 00:37:47,797
in our future exploration
of the universe.
697
00:37:47,799 --> 00:37:49,598
Plait: You know,
if you're a starship captain,
698
00:37:49,600 --> 00:37:52,735
what you need is
a galactic GPS system.
699
00:37:52,737 --> 00:37:55,838
Well it turns out,
neutron stars may be the answer.
700
00:38:11,189 --> 00:38:12,989
Narrator:
Astronomers often compare
701
00:38:12,991 --> 00:38:17,260
the steady flash of spinning
neutron stars, called "pulsars,"
702
00:38:17,262 --> 00:38:19,394
to cosmic lighthouses.
703
00:38:19,396 --> 00:38:23,132
These flashes are not only
remarkably reliable,
704
00:38:23,134 --> 00:38:28,737
each pulsar has its very own
distinct flickering beam.
705
00:38:28,739 --> 00:38:31,208
Each one has a slightly
different frequency.
706
00:38:31,210 --> 00:38:33,943
Each one has a slightly
different rate.
707
00:38:33,945 --> 00:38:37,346
Anyone in the galaxy,
no matter where you are,
708
00:38:37,348 --> 00:38:43,553
can all agree on the positions
of these pulsars.
709
00:38:43,555 --> 00:38:45,954
Narrator: The unique
signature of pulsars
710
00:38:45,956 --> 00:38:48,557
opens up intriguing
possibilities
711
00:38:48,559 --> 00:38:50,160
for the future
of space travel.
712
00:38:50,162 --> 00:38:53,162
��
713
00:38:55,633 --> 00:38:58,033
straughn: We would
basically be using pulsars
714
00:38:58,035 --> 00:39:01,036
to be able to sort of
triangulate where we're at.
715
00:39:01,038 --> 00:39:03,239
And because those pulses
are so precise,
716
00:39:03,241 --> 00:39:06,442
we can use that in a similar way
that we use GPS satellites
717
00:39:06,444 --> 00:39:07,944
that are stationed
above the earth.
718
00:39:10,982 --> 00:39:13,782
Narrator: Using pulsars
as navigational aids
719
00:39:13,784 --> 00:39:15,585
is not a new idea.
720
00:39:15,587 --> 00:39:18,988
It was recognized
by the NASA voyager mission
721
00:39:18,990 --> 00:39:22,058
in the 1970's.
722
00:39:22,060 --> 00:39:24,393
Affixed to the surface
of those spacecraft
723
00:39:24,395 --> 00:39:25,595
is a golden record.
724
00:39:25,597 --> 00:39:27,729
And on the plate
that covers that record
725
00:39:27,731 --> 00:39:31,067
is a pulsar map,
which in principle could tell
726
00:39:31,069 --> 00:39:34,536
an advanced alien civilization
how to find earth,
727
00:39:34,538 --> 00:39:37,006
because it uses
the position of earth
728
00:39:37,008 --> 00:39:39,207
relative to 14
known pulsars,
729
00:39:39,209 --> 00:39:41,410
as, effectively,
a way to triangulate
730
00:39:41,412 --> 00:39:42,878
the position
of our planet
731
00:39:42,880 --> 00:39:45,815
relative to all
of these pulsars.
732
00:39:45,817 --> 00:39:51,820
Narrator:
Aliens haven't made contact,
but NASA still uses pulsar maps.
733
00:39:51,822 --> 00:39:53,755
NASA recently
launched a satellite
734
00:39:53,757 --> 00:39:55,424
called "nicer sextant"
735
00:39:55,426 --> 00:39:57,961
that exists on the
international space station,
736
00:39:57,963 --> 00:40:00,763
that is being used to test
these types of theories.
737
00:40:00,765 --> 00:40:03,766
��
738
00:40:05,903 --> 00:40:09,504
��
739
00:40:09,506 --> 00:40:11,908
they've used pulsars
to figure out the location
740
00:40:11,910 --> 00:40:13,910
of an object orbiting
around the earth
741
00:40:13,912 --> 00:40:16,246
at 17,000
miles an hour,
742
00:40:16,248 --> 00:40:18,047
and they were able to
pinpoint its location
743
00:40:18,049 --> 00:40:19,581
to within three miles.
744
00:40:19,583 --> 00:40:21,717
That's pretty incredible.
745
00:40:21,719 --> 00:40:26,054
Narrator:
By recognizing their position
relative to known pulsars,
746
00:40:26,056 --> 00:40:29,725
future space missions
could navigate the universe.
747
00:40:29,727 --> 00:40:32,728
��
748
00:40:36,333 --> 00:40:39,335
neutron stars are gonna take us
on this incredible journey --
749
00:40:39,337 --> 00:40:40,736
something as necessary
750
00:40:40,738 --> 00:40:42,604
as knowing where you are
in the galaxy.
751
00:40:42,606 --> 00:40:44,540
We could be many hundreds
of light years away,
752
00:40:44,542 --> 00:40:46,275
but neutron stars
can actually show us
753
00:40:46,277 --> 00:40:47,810
where in the milky way
we are.
754
00:40:47,812 --> 00:40:50,846
��
755
00:40:52,950 --> 00:40:55,684
��
756
00:40:55,686 --> 00:40:56,952
I read a lot of
science fiction,
757
00:40:56,954 --> 00:40:59,688
and I love the idea
of being able to go
758
00:40:59,690 --> 00:41:02,158
from star to star,
planet to planet.
759
00:41:02,160 --> 00:41:05,828
It's kind of weird to think
that, in the future,
760
00:41:05,830 --> 00:41:08,364
as a galactic
coordinate grid,
761
00:41:08,366 --> 00:41:12,701
we might wind up using
these gigantic atomic nuclei,
762
00:41:12,703 --> 00:41:15,739
these rapidly spinning,
bizarrely-constructed,
763
00:41:15,741 --> 00:41:20,176
magnetic, fiercely gravitational
objects like neutron stars.
764
00:41:23,381 --> 00:41:26,115
Narrator: Neutron stars
have come a long way
765
00:41:26,117 --> 00:41:30,853
since being mistaken
for little green men.
766
00:41:30,855 --> 00:41:35,391
Once overlooked
as astronomical oddities,
767
00:41:35,393 --> 00:41:42,866
they've now taken center stage
as genuine stellar superstars.
768
00:41:42,868 --> 00:41:45,333
What's really exciting
about neutron stars is that,
769
00:41:45,335 --> 00:41:47,670
we're at the beginning
of studying them.
770
00:41:47,672 --> 00:41:49,938
We're not at the conclusion.
We've learned a lot,
771
00:41:49,940 --> 00:41:51,741
but there's a lot more
to be learned.
772
00:41:51,743 --> 00:41:56,412
Sutter: From the humble neutron
comes the most powerful,
773
00:41:56,414 --> 00:41:59,949
the most rapid,
the strongest magnetic field,
774
00:41:59,951 --> 00:42:03,619
the most exotic objects
in the cosmos.
775
00:42:03,621 --> 00:42:05,421
Thaller: I love the idea
of a Phoenix,
776
00:42:05,423 --> 00:42:07,957
something actually rising
from its own ashes.
777
00:42:07,959 --> 00:42:10,426
You think something dies,
and that's the end of the story,
778
00:42:10,428 --> 00:42:12,094
but something even
more beautiful,
779
00:42:12,096 --> 00:42:14,563
even more fascinating,
comes afterwards.
780
00:42:14,565 --> 00:42:16,699
I told you at the beginning,
and you didn't believe me,
781
00:42:16,701 --> 00:42:18,100
but now,
I hope you do --
782
00:42:18,102 --> 00:42:20,769
neutron stars
are the most fascinating
783
00:42:20,771 --> 00:42:23,305
astrophysical objects
in the universe.
63475
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