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Narrator:
26,000 light-years from earth,
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shrouded in cosmic dust and gas
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is a mysterious region
of space --
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the center of the milky way.
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The center of the milky way
galaxy is one of the strangest,
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most exotic and violent places
in our galaxy.
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Plait:
Gas streaming everywhere,
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radiation blasting out,
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stars moving willy-nilly.
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Thaller: And at the very heart
is the mysterious black hole,
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4 million times
the mass of the sun.
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Narrator: Now we're exploring
the center of the milky way
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like never before,
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uncovering powerful forces
that affect us all.
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Everything that happens at the
center of the milky way galaxy
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really is connected
to what's going on
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in the rest of the milky way.
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Narrator: Understanding
the center of our galaxy
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unlock secrets of our past,
present and future.
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-- Captions by vitac --
www.Vitac.Com
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captions paid for by
discovery communications
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♪
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♪
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March 2019.
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We focus the xmm-newton
space telescope
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on a region of space
around sagittarius a-star,
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the supermassive black hole
at the heart of our galaxy.
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We spot two huge columns of gas
glowing in x-ray light.
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♪
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the columns seem to be coming
from sagittarius a-star.
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Filippenko:
We see giant fountains of gas
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extending outward
from the central region
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as though it's like a wind
or a giant expulsion event.
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Narrator: The fountains of gas
extend 500 light-years above
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and below the supermassive
black hole.
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That's over a million times
the distance
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from the sun to neptune.
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It looks like this material
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is actually leaving
the vicinity of the black hole,
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like it's burping out
these giant, hot x-ray chimneys.
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Narrator: So why is sagittarius
a-star burping out hot gas?
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Typically, around a black hole,
you have an accretion disk
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funneling material
into the black hole,
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but all of it doesn't end up
in the black hole.
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Tremblay:
There is a little bit of gas
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falling onto it right now,
even as I'm speaking, right?
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As gas falls toward
the supermassive black hole,
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it becomes super heated.
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It liberates an enormous amount
of energy
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and that energy
has to go somewhere.
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Narrator: As gas spirals towards
the black hole,
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some of the material accelerates
to near the speed of light.
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It blasts out from
the accretion disk...
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...Creating chimneys
of superheated gas
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that seem to connect
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to two of the largest
structures in the galaxy --
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the milky way's fermi bubbles.
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A few years ago,
we noticed that, in fact,
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there are these giant bubbles
coming out of the very heart
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of the milky way galaxy.
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In each direction,
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there's a bubble
25,000 light-years long.
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Narrator:
But the gas-filled bubbles
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dwarf the chimneys
of superheated gas.
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Scientists wonder
if another more powerful force
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blew the bubbles.
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So what could have created
all of this superheated gas
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that actually blew these
tremendously large bubbles?
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Narrator: Supermassive black
holes in other galaxies
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might offer clues.
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Black holes at
the centers of galaxies
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go through
different phases.
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So they can be either active
or they can be calm.
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Sometimes black holes
at the centers of galaxies
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go through an active phase.
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And when that happens,
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the black hole is actively
feeding on material around it,
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which means it's growing
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and it also gives off
huge jets of radiation.
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Narrator: Calm supermassive
black holes
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release a trickle of hot gas.
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But when lots of material
falls on them,
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they can shoot out jets up
to millions of light-years long.
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♪
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at the current time,
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sagittarius a-star is
what we call quiescent.
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It's quiet.
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There is some material
swirling around it,
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but really not very much.
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But we don't think
that's always been the case.
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The centers of galaxies
are busy places.
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There are stars there.
There's gas there.
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There's dust there,
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and sometimes these things
fall into that black hole.
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Narrator:
6 million years ago,
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sagittarius a-star
may have had a feeding frenzy...
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...Eating too much
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and blasting out
the remains in huge jets.
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Those jets plow
through the galaxy
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initially at near the speed
of light.
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And as they do so,
they can wreak havoc
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or sculpt the evolution
of the galaxy
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that
they're propagating through.
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Narrator:
Sagittarius a-star's jets
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blasted gas out of the galaxy,
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creating the scars we see
as the fermi bubbles.
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Now, whatever caused those jets
seems to have turned off.
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It's not happening anymore
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and we're seeing sort
of the leftovers of them.
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But this is clearly a sign
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that sometime in the past
few million years,
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the black hole
in the center of our galaxy,
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sagittarius a-star, was actively
feeding on material around it.
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Material was falling into it
and blasting out this stuff.
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Narrator: The jets left
destruction in their wake.
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♪
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they may have also affected
the growth of our entire galaxy.
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These structures at the center
of our galaxy are important
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because they can either
shut off star formation
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or they can trigger
star formation.
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Tremblay: As those jets
propagate through the galaxy,
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they pile up gas
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and that gas can be then
triggered into star formation.
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But these jets can also impart
so much heat or energy feedback
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into the environment that
they prevent star formation.
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So black holes in many ways
conduct an orchestra,
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instructing or dictating
when stars can and cannot form.
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♪
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narrator:
In the center of the milky way,
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star-formation rates seem low.
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The jets could be responsible.
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But in 2017,
the alma telescope discovered
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that change is coming.
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Thaller: So alma's actually been
able to peer in
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to the heart of our galaxy
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and see that near
all this destruction,
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there might actually be a new
generation of stars forming.
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Narrator: Today, our calm
supermassive black hole
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could be helping
star formation in the core.
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But the fermi bubbles could be
evidence of a time
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when sagittarius a-star
shut down star formation.
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Could the supermassive
black hole
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roar back to life in the future?
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Tremblay: Sagittarius a-star
could roar back to life
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by just dumping some gas
onto it.
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And there's a lot of gas
at the center of our galaxy
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and it could wander into
the proximity
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of sagittarius a-star
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and ultimately fall
onto the event horizon
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and that would light it up.
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Narrator: If sagittarius a-star
eats enough gas...
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...It could shut down
star formation in the galaxy
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for millions of years.
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♪
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it could also give off x-rays
and gamma rays
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that may hit the earth.
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Sutter: Thankfully, our central
supermassive black hole
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is pretty quiet
and massive feeding events,
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massive energy events
are very, very rare.
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We don't necessarily
have much to worry about.
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Narrator: Sagittarius a-star
has reshaped our galaxy.
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If we want to survive
in the universe,
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we need to know more about
this monster black hole.
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The event horizon telescope
is on a mission to do just that.
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Question is can it succeed?
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♪
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narrator:
The center of the milky way
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is home to a supermassive
black hole,
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sagittarius a-star.
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At least we think it is.
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We've never seen
the supermassive
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black hole directly.
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But we have seen stars
racing around the core.
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Filippenko:
The speeds of the stars
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zipping around the center
of our milky way galaxy
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indicate that there's
something very massive
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and very compact there,
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indeed, 4 million times
as massive as our sun
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in a volume smaller
than that of our solar system.
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It's got to be
a black hole basically.
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Narrator: By measuring
the orbits of stars
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in our galaxy center...
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...We estimate
that sagittarius a-star
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is over a hundred times
wider than our sun.
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But despite its size,
the black hole is hidden.
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Tremblay:
One of the immediate challenges
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of actually observing
black holes
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is the fact that they don't emit
light and so you can't see them.
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Right? So we've never
actually seen a black hole.
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We've only seen the stuff
around a black hole
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or we have seen the effects
that that black hole
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imparts on its ambient
surroundings.
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Narrator: That's where the event
horizon telescope came in.
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Its goal was to photograph
sagittarius a-star,
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not the black hole itself,
but its shadow.
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Around it is this a gas that is
moving around the black hole
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that's super heated
to millions of degrees.
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And what the event
horizon telescope
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00:12:01,722 --> 00:12:04,389
is trying to see is
the shadow of a black hole.
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00:12:06,393 --> 00:12:09,994
Narrator: Light from the hot gas
around sagittarius a-star
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frames the giant shadow.
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It could be up to
93 million miles across.
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Problem is sagittarius
a-star is so far away
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that the supermassive black hole
is still incredibly hard to see.
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Plait:
Sagittarius a-star is big,
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but it's
26,000 light-years away.
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00:12:32,252 --> 00:12:34,719
A single light-year
is 6 trillion miles.
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So this is a long, long walk.
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And even though it's big,
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that distance shrinks
its apparent size
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to just
a tiny little dot on the sky.
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Narrator: To see the tiny dot,
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00:12:47,968 --> 00:12:51,803
we need a telescope
the size of the earth.
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00:12:51,805 --> 00:12:52,904
How do you possibly do that?
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00:12:52,906 --> 00:12:56,474
You can't build
that telescope, right?
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00:12:56,476 --> 00:12:57,575
Well, there's a trick.
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00:12:57,577 --> 00:12:59,244
You actually get
a few different telescopes
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00:12:59,246 --> 00:13:02,413
and you spread them out
over the surface of the earth.
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00:13:02,415 --> 00:13:08,052
♪
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00:13:08,054 --> 00:13:11,523
doeleman: And when we had
all of these sites together,
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00:13:11,525 --> 00:13:14,626
we wind up being able
to take an image of something
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00:13:14,628 --> 00:13:18,930
that is really,
really impossibly small.
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00:13:18,932 --> 00:13:22,300
Narrator: To gather enough light
to see a target this small,
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00:13:22,302 --> 00:13:25,103
the team take
long-exposure images
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00:13:25,105 --> 00:13:27,906
of sagittarius a-star's
shadow...
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00:13:31,711 --> 00:13:34,579
...But there's a problem.
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00:13:34,581 --> 00:13:37,382
The accretion disk moves
too much for us
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00:13:37,384 --> 00:13:39,384
to capture a clear image.
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00:13:42,589 --> 00:13:44,689
When you're taking
a long exposure of a person,
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00:13:44,691 --> 00:13:46,157
right,
you need them to be really,
231
00:13:46,159 --> 00:13:47,926
really still, right?
232
00:13:47,928 --> 00:13:49,494
Because if they're moving around
a lot,
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00:13:49,496 --> 00:13:51,362
they're going to blur
the image out.
234
00:13:51,364 --> 00:13:52,831
And that kind of thing
is happening
235
00:13:52,833 --> 00:13:54,833
when we observe
sagittarius a-star
236
00:13:54,835 --> 00:13:57,235
because it is unwilling
to sit still for us.
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00:13:57,237 --> 00:13:58,937
It is booming and banging
and flashing
238
00:13:58,939 --> 00:14:03,174
on the timescale
of literally hours.
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00:14:03,176 --> 00:14:06,311
Narrator: As glowing material
orbits the black hole
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00:14:06,313 --> 00:14:07,912
at 30% the speed of light,
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00:14:07,914 --> 00:14:11,416
sagittarius a-star's
shadow blurs.
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00:14:13,820 --> 00:14:16,120
Future developments may allow us
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00:14:16,122 --> 00:14:18,790
to see sagittarius a-star
clearly.
244
00:14:21,561 --> 00:14:24,429
For now, we can't capture
an accurate image
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00:14:24,431 --> 00:14:27,265
of our galaxy's
supermassive black hole.
246
00:14:30,070 --> 00:14:33,404
But the hunt to see
a supermassive black hole
247
00:14:33,406 --> 00:14:34,839
wasn't over.
248
00:14:34,841 --> 00:14:38,676
The event horizon telescope
turned to another galaxy
249
00:14:38,678 --> 00:14:43,548
54 million
light-years away -- m87.
250
00:14:44,985 --> 00:14:48,086
M87 is an absolute beast
of a galaxy.
251
00:14:48,088 --> 00:14:50,221
It's the so-called
brightest cluster galaxy.
252
00:14:50,223 --> 00:14:52,991
These are among the largest
galaxies in the universe.
253
00:14:55,028 --> 00:14:56,895
Narrator: And m87 is home
254
00:14:56,897 --> 00:14:59,764
to another supermassive
black hole --
255
00:14:59,766 --> 00:15:02,800
the giant m87 star.
256
00:15:04,237 --> 00:15:09,607
M87 star is so massive
that the gravitational region
257
00:15:09,609 --> 00:15:12,176
that's interesting
is actually easier to image
258
00:15:12,178 --> 00:15:14,579
than the black hole
in our own galaxy.
259
00:15:17,651 --> 00:15:22,120
Narrator: M87 star is over
a thousand times more massive
260
00:15:22,122 --> 00:15:24,188
than sagittarius a-star
261
00:15:24,190 --> 00:15:28,159
and has a far
larger accretion disk.
262
00:15:28,161 --> 00:15:31,496
When photographing a black hole,
size matters,
263
00:15:31,498 --> 00:15:36,034
because big accretion disks
project more stable light,
264
00:15:36,036 --> 00:15:39,237
so images of them
don't blur as much.
265
00:15:42,242 --> 00:15:44,575
In April of 2019,
266
00:15:44,577 --> 00:15:49,113
the event horizon team
unveiled their image.
267
00:15:49,115 --> 00:15:52,717
We have seen what we thought
was unseeable.
268
00:15:52,719 --> 00:15:57,388
We have seen and taken a picture
of a black hole.
269
00:15:57,390 --> 00:15:58,656
[ applause ]
270
00:15:58,658 --> 00:16:05,229
♪
271
00:16:05,231 --> 00:16:06,631
I've been working
on this project
272
00:16:06,633 --> 00:16:09,634
for almost six years now,
and so, this is something
273
00:16:09,636 --> 00:16:13,972
we've been looking forward to
for a really long time.
274
00:16:13,974 --> 00:16:16,607
Narrator: Capturing this image
took decades of work
275
00:16:16,609 --> 00:16:20,478
by hundreds of scientists
all over the world.
276
00:16:23,350 --> 00:16:25,783
Galison: I was really stunned.
277
00:16:25,785 --> 00:16:29,721
Suddenly, when you say that's
the real thing, that's amazing.
278
00:16:29,723 --> 00:16:31,489
It really affected me.
279
00:16:31,491 --> 00:16:34,525
This is something
6 1/2 billion times
280
00:16:34,527 --> 00:16:36,194
the mass of the sun,
281
00:16:36,196 --> 00:16:41,599
55 million light-years away
and we're looking at it.
282
00:16:41,601 --> 00:16:44,535
Tremblay: So when you look at
the image, it's totally fine.
283
00:16:44,537 --> 00:16:46,070
You're totally forgiven
for thinking,
284
00:16:46,072 --> 00:16:48,606
"ah, it looks a little blurry."
285
00:16:48,608 --> 00:16:52,076
but I cannot reiterate enough
286
00:16:52,078 --> 00:16:55,179
how profound
this image actually is.
287
00:16:55,181 --> 00:16:59,283
We are seeing just a hair's
width away from a discontinuity
288
00:16:59,285 --> 00:17:01,652
in the fabric
of space-time itself.
289
00:17:01,654 --> 00:17:05,523
Actually seeing so close
to an actual event horizon,
290
00:17:05,525 --> 00:17:07,959
a discontinuity in the fabric
of space-time,
291
00:17:07,961 --> 00:17:11,396
never seemed possible.
292
00:17:11,398 --> 00:17:14,966
Narrator: This image of the
heart of a distant galaxy
293
00:17:14,968 --> 00:17:19,570
helps us understand supermassive
black holes like never before.
294
00:17:21,741 --> 00:17:24,342
Straughn: When we observe
supermassive black holes
295
00:17:24,344 --> 00:17:26,711
in other galaxies,
including the one in m87,
296
00:17:26,713 --> 00:17:28,946
we're able to learn more about
the big picture
297
00:17:28,948 --> 00:17:32,683
of how these massive black holes
form and evolve over time.
298
00:17:32,685 --> 00:17:34,419
And that in turn,
helps us understand
299
00:17:34,421 --> 00:17:35,753
how our milky way galaxy
300
00:17:35,755 --> 00:17:38,256
and its super massive
black hole has formed.
301
00:17:40,427 --> 00:17:42,794
Bouman: By studying, not just
making images of black holes,
302
00:17:42,796 --> 00:17:44,695
but making videos
of black holes,
303
00:17:44,697 --> 00:17:47,799
and seeing as that gas
is spinning around it,
304
00:17:47,801 --> 00:17:50,902
we can try to map around
a black hole more precisely
305
00:17:50,904 --> 00:17:52,870
and learn about its dynamics.
306
00:17:54,974 --> 00:17:57,375
Narrator: An image
of sagittarius a-star
307
00:17:57,377 --> 00:17:58,776
remains out of reach,
308
00:17:58,778 --> 00:18:02,914
but in 2018, it shows
a deadly side to its character.
309
00:18:04,684 --> 00:18:07,318
The supermassive black
hole's accretion disk
310
00:18:07,320 --> 00:18:10,121
releases huge, powerful flares,
311
00:18:10,123 --> 00:18:13,791
and they could be pointed
right at us.
312
00:18:22,001 --> 00:18:26,571
Narrator: In 2018, astronomers
were studying a special star
313
00:18:26,573 --> 00:18:29,807
orbiting our galaxy's
supermassive black hole.
314
00:18:29,809 --> 00:18:33,211
The star passes close
to sagittarius a-star --
315
00:18:33,213 --> 00:18:35,646
every 16 years.
316
00:18:35,648 --> 00:18:40,284
It's called s2, and by studying
this star's fly-by,
317
00:18:40,286 --> 00:18:44,021
we hope to learn more
about sagittarius a-star.
318
00:18:45,358 --> 00:18:48,226
Tremblay: We think that s2 may
be the very closest star
319
00:18:48,228 --> 00:18:51,662
to the supermassive black hole
in the center of our galaxy.
320
00:18:51,664 --> 00:18:53,764
At closest approach
to sag a-star,
321
00:18:53,766 --> 00:18:58,369
s2 comes within 17 light hours
or so of the surface.
322
00:19:00,907 --> 00:19:04,142
Narrator: The supermassive black
hole's powerful gravity
323
00:19:04,144 --> 00:19:09,180
accelerates the star
to 17 million miles an hour.
324
00:19:09,182 --> 00:19:12,517
That's fast enough to travel
from new york to l.A.
325
00:19:12,519 --> 00:19:15,620
In half a second,
326
00:19:15,622 --> 00:19:19,357
but it's not the star's speed
that excites scientists.
327
00:19:20,393 --> 00:19:23,194
This is a great star, because
it's on an elliptical orbit
328
00:19:23,196 --> 00:19:25,763
that takes it fairly far
from the black hole,
329
00:19:25,765 --> 00:19:27,064
but every few years,
330
00:19:27,066 --> 00:19:30,635
it passes right above
the supermassive black hole.
331
00:19:32,705 --> 00:19:36,941
Narrator: As we tracked s2's
swing around sagittarius a-star,
332
00:19:36,943 --> 00:19:40,511
we detected powerful
bursts of infrared light
333
00:19:40,513 --> 00:19:44,182
coming from the direction
of the supermassive black hole.
334
00:19:46,653 --> 00:19:48,319
Plait:
There's a blob of gas
335
00:19:48,321 --> 00:19:51,022
that is orbiting very close
to the black hole,
336
00:19:51,024 --> 00:19:53,558
and it was flaring
as it went around.
337
00:19:53,560 --> 00:19:55,726
There were three separate
flares of light
338
00:19:55,728 --> 00:19:59,063
that they were able to detect.
339
00:19:59,065 --> 00:20:00,965
Narrator:
The flares didn't come directly
340
00:20:00,967 --> 00:20:04,435
from
the supermassive black hole,
341
00:20:04,437 --> 00:20:07,672
they came from
the material around it.
342
00:20:10,210 --> 00:20:12,777
The flares that were discovered
are thought to originate
343
00:20:12,779 --> 00:20:14,278
from magnetic storms
344
00:20:14,280 --> 00:20:18,482
in this very, very hot turbulent
gas around the black hole.
345
00:20:20,887 --> 00:20:23,254
Narrator: The extreme heat
in the accretion disk
346
00:20:23,256 --> 00:20:26,390
strips electrons
from atoms of gas.
347
00:20:26,392 --> 00:20:30,261
The stripped electrons
and hot gas form a plasma,
348
00:20:30,263 --> 00:20:32,964
which creates powerful
magnetic fields
349
00:20:32,966 --> 00:20:35,266
when accelerated to high speeds.
350
00:20:37,237 --> 00:20:39,503
Tremblay: Because some super
massive black holes
351
00:20:39,505 --> 00:20:40,805
have these superheated,
352
00:20:40,807 --> 00:20:44,175
rapidly spinning vortices
of gas swirling around them,
353
00:20:44,177 --> 00:20:46,210
you get these very,
very powerful,
354
00:20:46,212 --> 00:20:48,546
very tightly wound
magnetic fields.
355
00:20:50,617 --> 00:20:52,750
And there's energy stored
in that magnetic field.
356
00:20:52,752 --> 00:20:55,686
It's like a bunch of piano wires
all tangled up.
357
00:20:55,688 --> 00:20:58,589
And if these things interact
with each other, they can snap,
358
00:20:58,591 --> 00:21:01,225
and when they snap,
that energy is released.
359
00:21:05,431 --> 00:21:07,698
Tremblay: You'll get this
enormous release of energy
360
00:21:07,700 --> 00:21:11,269
as these coils of magnetic
fields effectively snap.
361
00:21:11,271 --> 00:21:15,906
And when they do so, just like
on the surface of our sun,
362
00:21:15,908 --> 00:21:18,542
they release
an enormous flare of gas.
363
00:21:22,148 --> 00:21:27,385
Narrator: These powerful flares
can be millions of miles wide
364
00:21:27,387 --> 00:21:31,622
and come packed with superheated
gas and plasma.
365
00:21:35,194 --> 00:21:37,995
Solar flares release
as much energy
366
00:21:37,997 --> 00:21:40,698
as 10 million volcanic
explosions.
367
00:21:40,700 --> 00:21:45,569
♪
368
00:21:45,571 --> 00:21:50,508
flares from sagittarius
a-star's accretion disk
369
00:21:50,510 --> 00:21:55,579
are like millions of solar
flares all going off at once.
370
00:21:58,318 --> 00:22:01,986
It's kind of like comparing a
nuclear weapon to a firecracker.
371
00:22:04,123 --> 00:22:06,857
Narrator:
Sagittarius a-star's flares
372
00:22:06,859 --> 00:22:09,527
release intense blasts
of radiation,
373
00:22:09,529 --> 00:22:12,563
but by watching the flares
from earth,
374
00:22:12,565 --> 00:22:14,532
we can learn about
the orientation
375
00:22:14,534 --> 00:22:17,601
of the supermassive
black hole's accretion disk.
376
00:22:19,372 --> 00:22:21,472
Tremblay: This gas that's in
this accretion disk
377
00:22:21,474 --> 00:22:25,242
around the black hole
is like a friendly helper
378
00:22:25,244 --> 00:22:27,378
shining a flashlight
back toward earth.
379
00:22:27,380 --> 00:22:29,780
And we can watch the orbit
of these flashlights
380
00:22:29,782 --> 00:22:32,116
and help understand
the orientation of gas
381
00:22:32,118 --> 00:22:33,884
that swirls
around the black hole.
382
00:22:37,457 --> 00:22:39,423
We think we're getting
a bird's-eye view of it.
383
00:22:39,425 --> 00:22:41,092
And looking down the barrel,
384
00:22:41,094 --> 00:22:45,596
we're looking at the accretion
disk basically face-on.
385
00:22:45,598 --> 00:22:48,132
That means that any material
that gets blasted away
386
00:22:48,134 --> 00:22:50,968
from the black hole
could be aimed right at us.
387
00:22:53,973 --> 00:22:57,475
Narrator: Should we be worried
about the flares reaching earth?
388
00:22:59,078 --> 00:23:01,245
Plait: It sounds worrisome,
this blob of gas
389
00:23:01,247 --> 00:23:03,481
emitting these
huge flares of light,
390
00:23:03,483 --> 00:23:07,251
but you've got to realize,
this is 26,000 light-years away.
391
00:23:07,253 --> 00:23:08,552
That is a long way.
392
00:23:08,554 --> 00:23:11,122
It took an extremely sensitive
detector
393
00:23:11,124 --> 00:23:13,824
on one of the largest
telescopes on earth
394
00:23:13,826 --> 00:23:16,727
to be able to see this at all.
395
00:23:16,729 --> 00:23:18,996
Narrator:
Earth is safe for now,
396
00:23:18,998 --> 00:23:22,199
but the more we learn
about the galaxy center,
397
00:23:22,201 --> 00:23:25,136
the more terrifying it becomes.
398
00:23:25,138 --> 00:23:27,238
We know of sagittarius a-star,
399
00:23:27,240 --> 00:23:29,206
the central supermassive
black hole,
400
00:23:29,208 --> 00:23:31,008
but now we're beginning
to suspect
401
00:23:31,010 --> 00:23:33,577
that it might not be alone.
402
00:23:35,214 --> 00:23:37,815
Narrator:
A dangerous swarm of black holes
403
00:23:37,817 --> 00:23:41,719
could be racing around
the center of the milky way.
404
00:23:41,721 --> 00:23:44,922
Thousands more may
be hiding from sight.
405
00:23:47,960 --> 00:23:53,697
♪
406
00:23:53,699 --> 00:23:57,601
narrator: The supermassive black
hole, sagittarius a-star,
407
00:23:57,603 --> 00:24:00,070
dominates the center
of the milky way...
408
00:24:02,108 --> 00:24:04,041
...Affecting star formation...
409
00:24:06,212 --> 00:24:09,380
...And carving out vast
gas bubbles in space.
410
00:24:11,751 --> 00:24:16,554
But sagittarius a-star might not
be the only black hole in town,
411
00:24:16,556 --> 00:24:19,423
or even the most dangerous.
412
00:24:21,828 --> 00:24:23,027
Thaller:
We've known for a long time
413
00:24:23,029 --> 00:24:24,462
that there's a supermassive
black hole
414
00:24:24,464 --> 00:24:26,363
in the very heart
of our galaxy,
415
00:24:26,365 --> 00:24:29,533
but there may be an angry swarm
of smaller black holes,
416
00:24:29,535 --> 00:24:32,303
buzzing all around it.
417
00:24:32,305 --> 00:24:34,605
Narrator: In April of 2018,
418
00:24:34,607 --> 00:24:37,308
astronomers led
by columbia university
419
00:24:37,310 --> 00:24:39,844
revealed the results
of a hunting mission
420
00:24:39,846 --> 00:24:42,012
in the center of the galaxy.
421
00:24:42,014 --> 00:24:45,783
They'd used 12 years
of chandra observatory data
422
00:24:45,785 --> 00:24:49,987
to seek out
stellar mass black holes.
423
00:24:49,989 --> 00:24:52,590
Black holes that are made
from the death of stars,
424
00:24:52,592 --> 00:24:54,225
from supernova explosions,
425
00:24:54,227 --> 00:24:56,927
are called stellar
mass black holes.
426
00:24:56,929 --> 00:25:02,099
♪
427
00:25:02,101 --> 00:25:04,068
and these are made from stars
428
00:25:04,070 --> 00:25:06,871
that were many times
the mass of the sun.
429
00:25:09,709 --> 00:25:14,345
Narrator: Finding stellar mass
black holes is tough.
430
00:25:14,347 --> 00:25:17,381
Light can't escape
a black hole's gravity,
431
00:25:17,383 --> 00:25:19,383
so we can't see them directly.
432
00:25:22,688 --> 00:25:26,924
And stellar mass black holes
are only tens of miles wide,
433
00:25:26,926 --> 00:25:30,027
making them almost impossible
to detect.
434
00:25:32,265 --> 00:25:34,698
So astronomers look
for a special type
435
00:25:34,700 --> 00:25:36,667
of stellar mass black hole.
436
00:25:40,339 --> 00:25:44,275
One of the ways that we look
for stellar mass black holes,
437
00:25:44,277 --> 00:25:50,047
is that they often are vampires
eating a companion star.
438
00:25:53,786 --> 00:25:58,188
Narrator: These vampires are
part of a binary pair,
439
00:25:58,190 --> 00:26:02,560
a stellar mass black hole
in orbit with a living star,
440
00:26:02,562 --> 00:26:05,930
the black hole feasting
on its partner.
441
00:26:07,366 --> 00:26:08,732
Tremblay: That black hole
442
00:26:08,734 --> 00:26:11,468
is like a very, very deadly
parasite for that star.
443
00:26:11,470 --> 00:26:14,271
It is ripping mass
off the surface of that star,
444
00:26:14,273 --> 00:26:17,641
and that matter is raining down
toward the black hole itself.
445
00:26:20,980 --> 00:26:23,047
Sutter:
And that material lights up,
446
00:26:23,049 --> 00:26:25,616
so this allows us
to hunt for black holes,
447
00:26:25,618 --> 00:26:28,686
not through taking pictures
of black holes directly,
448
00:26:28,688 --> 00:26:32,990
but through seeing the material
falling to its doom.
449
00:26:32,992 --> 00:26:35,059
Narrator: The problem is,
450
00:26:35,061 --> 00:26:37,394
gas and dust spread
throughout the galaxy
451
00:26:37,396 --> 00:26:41,599
stops visible light from
the binary pair reaching earth.
452
00:26:41,601 --> 00:26:44,702
But the binary pair release
another type of light
453
00:26:44,704 --> 00:26:48,806
that passes through the gas
and dust more easily --
454
00:26:48,808 --> 00:26:50,741
x-rays.
455
00:26:50,743 --> 00:26:53,277
Mingarelli: The system itself
is emitting x-rays,
456
00:26:53,279 --> 00:26:55,279
so they're called
x-ray binaries.
457
00:26:55,281 --> 00:26:57,948
So these are useful,
because the x-ray emission
458
00:26:57,950 --> 00:26:59,450
can be very powerful
459
00:26:59,452 --> 00:27:02,152
and can be potentially seen
from the earth,
460
00:27:02,154 --> 00:27:04,221
even though the binary
is very far away,
461
00:27:04,223 --> 00:27:06,023
say, at the galactic center.
462
00:27:08,628 --> 00:27:12,396
Narrator: The glowing disks of
material in x-ray binary systems
463
00:27:12,398 --> 00:27:16,000
are almost a million times
smaller than the accretion disk
464
00:27:16,002 --> 00:27:19,336
surrounding sagittarius a-star,
too small
465
00:27:19,338 --> 00:27:23,540
for us to see the material
swirling around them in detail.
466
00:27:25,044 --> 00:27:30,447
So, we see the x-ray binaries
as pinpricks of x-ray light.
467
00:27:33,185 --> 00:27:36,787
Astronomers detect
12 of these x-ray binaries
468
00:27:36,789 --> 00:27:40,357
in a small 3-light-year-wide
patch of space
469
00:27:40,359 --> 00:27:42,192
at the galactic center.
470
00:27:42,194 --> 00:27:44,762
And that means that there could
be a much larger collection
471
00:27:44,764 --> 00:27:47,765
of these relatively tiny stellar
mass black holes
472
00:27:47,767 --> 00:27:51,268
in the heart of our galaxy.
473
00:27:51,270 --> 00:27:53,671
If black holes form the way
we think they do,
474
00:27:53,673 --> 00:27:56,440
there very likely
may be swarms of black holes
475
00:27:56,442 --> 00:27:58,542
racing around
sagittarius a-star.
476
00:28:01,480 --> 00:28:04,448
Narrator: But x-ray binaries
that are powerful enough for us
477
00:28:04,450 --> 00:28:08,852
to detect are incredibly rare.
478
00:28:08,854 --> 00:28:13,590
So we estimate that for the
dozen x-ray binaries discovered,
479
00:28:13,592 --> 00:28:15,526
there could be up
to a thousand more.
480
00:28:15,528 --> 00:28:20,798
♪
481
00:28:20,800 --> 00:28:25,536
in total, there could be
20,000 stellar mass black holes
482
00:28:25,538 --> 00:28:28,672
in this 3-light-year
region of space.
483
00:28:28,674 --> 00:28:38,048
♪
484
00:28:38,050 --> 00:28:41,852
why are these black holes
swarming in the galaxy center?
485
00:28:41,854 --> 00:28:45,789
It appears they've migrated
from the rest of the milky way.
486
00:28:47,326 --> 00:28:49,359
Tremblay: Through a process
called dynamical friction,
487
00:28:49,361 --> 00:28:51,862
black holes can actually sink
to the centers of galaxies
488
00:28:51,864 --> 00:28:55,933
very, very rapidly, like
dropping a stone into a pond.
489
00:28:55,935 --> 00:28:58,101
What that means
is that an errant,
490
00:28:58,103 --> 00:29:00,003
wandering black hole
might eventually
491
00:29:00,005 --> 00:29:02,606
find its way toward the center
of our own galaxy,
492
00:29:02,608 --> 00:29:06,577
where sagittarius a-star
resides.
493
00:29:06,579 --> 00:29:10,614
Narrator: As stellar mass black
holes orbit the galaxy,
494
00:29:10,616 --> 00:29:12,683
they interact gravitationally
495
00:29:12,685 --> 00:29:15,586
with stars and clouds
of gas and dust.
496
00:29:17,389 --> 00:29:20,524
These interactions
push the black holes
497
00:29:20,526 --> 00:29:23,827
towards the center
of the galaxy,
498
00:29:23,829 --> 00:29:25,429
where the black holes swarm.
499
00:29:25,431 --> 00:29:30,367
♪
500
00:29:30,369 --> 00:29:34,471
a swarm of stellar mass
black holes sounds deadly,
501
00:29:34,473 --> 00:29:37,007
but it may not be
the most lethal thing
502
00:29:37,009 --> 00:29:38,842
in the center of the milky way.
503
00:29:41,313 --> 00:29:45,382
A surprising observation
indicates that there is a lot
504
00:29:45,384 --> 00:29:49,386
of antimatter
in the center of our galaxy.
505
00:29:49,388 --> 00:29:52,523
Narrator: And when antimatter
meets matter,
506
00:29:52,525 --> 00:29:55,225
the results are explosive.
507
00:29:58,898 --> 00:30:05,602
♪
508
00:30:05,604 --> 00:30:07,437
narrator: In 2017,
509
00:30:07,439 --> 00:30:11,875
astronomers tried to solve
a decades-old cosmic mystery...
510
00:30:14,814 --> 00:30:17,748
...Unexplained
high-energy radiation
511
00:30:17,750 --> 00:30:19,683
streaming through our galaxy.
512
00:30:23,422 --> 00:30:25,923
At first, we didn't know
where it was from.
513
00:30:28,427 --> 00:30:31,228
But we discovered
it was gamma radiation
514
00:30:31,230 --> 00:30:34,932
coming from somewhere
in the center of the milky way.
515
00:30:37,536 --> 00:30:40,237
The question is,
what's making these gamma rays?
516
00:30:40,239 --> 00:30:41,972
That's hard to do.
517
00:30:41,974 --> 00:30:43,507
It's not like
you can rub your hands together
518
00:30:43,509 --> 00:30:46,910
and generate gamma rays.
519
00:30:46,912 --> 00:30:48,979
Narrator: When we took a closer
look at the gamma rays,
520
00:30:48,981 --> 00:30:52,783
we discovered the signature
of the most explosive substance
521
00:30:52,785 --> 00:30:55,419
in the universe -- antimatter.
522
00:30:59,258 --> 00:31:02,559
Antimatter is like
normal matter
523
00:31:02,561 --> 00:31:04,561
but with opposite charge.
524
00:31:04,563 --> 00:31:07,030
That's it.
It's matter's evil twin.
525
00:31:09,134 --> 00:31:11,935
Narrator:
When evil twin meets good twin,
526
00:31:11,937 --> 00:31:14,404
it is not a happy reunion.
527
00:31:17,309 --> 00:31:18,742
Plait: Antimatter is scary.
528
00:31:18,744 --> 00:31:21,445
It's not like you want
to have some in your kitchen.
529
00:31:21,447 --> 00:31:23,647
This stuff is very,
very explosive,
530
00:31:23,649 --> 00:31:25,749
if you want to think
of it that way.
531
00:31:25,751 --> 00:31:27,484
If it touches normal matter,
532
00:31:27,486 --> 00:31:29,786
it releases a huge
amount of energy.
533
00:31:31,724 --> 00:31:33,757
Narrator: When matter
and antimatter combine,
534
00:31:33,759 --> 00:31:36,159
they annihilate each other
and transform
535
00:31:36,161 --> 00:31:39,663
into high-energy radiation,
just like the gamma rays
536
00:31:39,665 --> 00:31:42,766
seen streaming out
of the center of the milky way.
537
00:31:44,603 --> 00:31:47,537
We see antimatter
throughout the galaxy,
538
00:31:47,539 --> 00:31:49,973
but strangely,
the galactic center
539
00:31:49,975 --> 00:31:54,511
seemed to have 40% more
antimatter than anywhere else.
540
00:31:56,815 --> 00:31:58,649
Right now in the heart
of our galaxy,
541
00:31:58,651 --> 00:32:01,685
we actually observe
fountains of antimatter
542
00:32:01,687 --> 00:32:04,655
that are producing
10 trillion tons
543
00:32:04,657 --> 00:32:07,824
of antimatter
every second.
544
00:32:07,826 --> 00:32:09,526
One of the big questions
that we've wondered about
545
00:32:09,528 --> 00:32:12,429
for a very long time, is what's
the origin of this stuff?
546
00:32:15,801 --> 00:32:19,403
Narrator: Initially,
there were several suspects.
547
00:32:19,405 --> 00:32:21,171
Plait: One possible source
of antimatter
548
00:32:21,173 --> 00:32:24,808
is the central black hole,
sagittarius a-star.
549
00:32:24,810 --> 00:32:26,443
Matter can be swirling
around this
550
00:32:26,445 --> 00:32:28,178
and it can have
such high energy
551
00:32:28,180 --> 00:32:29,947
that it can create antimatter.
552
00:32:33,218 --> 00:32:34,918
Narrator: But the antimatter
553
00:32:34,920 --> 00:32:37,054
isn't coming
from a single point,
554
00:32:37,056 --> 00:32:41,558
it's spread across thousands
of light-years of space.
555
00:32:41,560 --> 00:32:43,226
So sagittarius a-star
556
00:32:43,228 --> 00:32:46,730
can't be the source
of the gamma-ray stream.
557
00:32:49,668 --> 00:32:52,569
Another suspect
was dark matter.
558
00:32:55,040 --> 00:32:56,573
One of the biggest mysteries
in the universe
559
00:32:56,575 --> 00:32:58,642
right now is dark matter.
560
00:32:58,644 --> 00:33:01,511
We know that the majority
of mass in the universe
561
00:33:01,513 --> 00:33:03,146
is not in the same form
that we are.
562
00:33:03,148 --> 00:33:04,915
It's not made of atoms,
563
00:33:04,917 --> 00:33:07,451
but whatever sort of particle
it is or may be,
564
00:33:07,453 --> 00:33:10,854
if these things collide,
they can produce antimatter,
565
00:33:10,856 --> 00:33:12,589
and that will produce
the gamma rays.
566
00:33:12,591 --> 00:33:15,225
So it's possible that as we look
into the heart of the galaxy
567
00:33:15,227 --> 00:33:17,027
and see these extra gamma rays,
568
00:33:17,029 --> 00:33:19,629
that's the signal
that dark matter is there.
569
00:33:23,669 --> 00:33:26,737
Narrator: But the gamma ray
stream we detected is too weak
570
00:33:26,739 --> 00:33:29,139
to have been created
by dark matter.
571
00:33:31,810 --> 00:33:35,679
Then we had a breakthrough.
572
00:33:35,681 --> 00:33:40,317
We discovered that a special
metal called titanium-44
573
00:33:40,319 --> 00:33:43,487
could be responsible
for the gamma-ray stream.
574
00:33:47,326 --> 00:33:50,527
Titanium-44 is a highly
radioactive element.
575
00:33:50,529 --> 00:33:52,229
That means that
it wants to decay
576
00:33:52,231 --> 00:33:54,064
into other types of nuclei.
577
00:33:57,069 --> 00:33:59,636
Narrator:
When titanium-44 decays,
578
00:33:59,638 --> 00:34:01,438
it gives off antimatter.
579
00:34:01,440 --> 00:34:05,675
But to produce the antimatter
seen in the galaxy's core,
580
00:34:05,677 --> 00:34:09,112
you would need
a lot of titanium-44.
581
00:34:09,114 --> 00:34:14,217
It could be created
in rare energetic events,
582
00:34:14,219 --> 00:34:18,655
in the collision of two dead
stars -- white dwarfs.
583
00:34:20,559 --> 00:34:23,393
A white dwarf star is a star
that didn't have enough mass
584
00:34:23,395 --> 00:34:25,996
when it died
to actually become a supernova.
585
00:34:25,998 --> 00:34:28,665
It just sort of cools off
as a dead little cinder.
586
00:34:28,667 --> 00:34:30,333
But what if you have
two white dwarfs
587
00:34:30,335 --> 00:34:32,135
that are orbiting
around each other,
588
00:34:32,137 --> 00:34:34,938
and as they come closer
and closer and collide,
589
00:34:34,940 --> 00:34:36,907
all of a sudden now,
you have enough mass
590
00:34:36,909 --> 00:34:39,276
to actually kick
a supernova explosion off.
591
00:34:39,278 --> 00:34:44,347
♪
592
00:34:44,349 --> 00:34:46,183
these particular kinds
of supernovae
593
00:34:46,185 --> 00:34:49,052
are very good
at producing titanium-44.
594
00:34:50,856 --> 00:34:53,657
So these kinds of supernovas
are very, very good
595
00:34:53,659 --> 00:34:55,292
at making antimatter.
596
00:34:57,863 --> 00:35:00,864
Narrator: These supernovas
erupt in the core of the galaxy
597
00:35:00,866 --> 00:35:03,200
once every 2,000 years.
598
00:35:06,205 --> 00:35:09,139
But outside of the core
in the disk of the galaxy
599
00:35:09,141 --> 00:35:11,374
where our solar system orbits...
600
00:35:13,512 --> 00:35:16,746
...These supernovas happen
three times as often.
601
00:35:18,317 --> 00:35:22,152
So the gamma ray observations
were wrong.
602
00:35:22,154 --> 00:35:25,856
There isn't more antimatter
in the heart of the galaxy.
603
00:35:25,858 --> 00:35:28,091
It's our region of the galaxy
604
00:35:28,093 --> 00:35:31,194
that contains
the most antimatter.
605
00:35:33,365 --> 00:35:36,133
Question is, are we in danger?
606
00:35:38,570 --> 00:35:39,769
Plait:
If you take an ounce of matter
607
00:35:39,771 --> 00:35:41,738
and an ounce of antimatter
and collide them,
608
00:35:41,740 --> 00:35:45,175
you're generating
a megaton of energy,
609
00:35:45,177 --> 00:35:49,779
the equivalent of a million tons
of tnt exploding.
610
00:35:49,781 --> 00:35:51,748
So you don't need
much antimatter to generate
611
00:35:51,750 --> 00:35:54,684
a vast amount of energy.
612
00:35:54,686 --> 00:35:56,887
But the thing you have
to remember is we live
613
00:35:56,889 --> 00:35:59,156
in this wonderful,
dramatic environment
614
00:35:59,158 --> 00:36:00,357
of a larger universe.
615
00:36:00,359 --> 00:36:01,725
It's not dangerous.
616
00:36:01,727 --> 00:36:04,761
It's very far away from us,
and it's fascinating.
617
00:36:07,232 --> 00:36:10,567
But all of this antimatter
is being produced in our galaxy,
618
00:36:10,569 --> 00:36:13,603
so just sit back
and enjoy the fireworks.
619
00:36:15,874 --> 00:36:18,375
Narrator: The center
of the milky way
620
00:36:18,377 --> 00:36:19,876
is violent and extreme,
621
00:36:19,878 --> 00:36:22,812
but things could get
a whole lot worse.
622
00:36:24,683 --> 00:36:26,850
Rogue supermassive black holes
623
00:36:26,852 --> 00:36:30,053
could be
lurking near our galaxy,
624
00:36:30,055 --> 00:36:34,024
and they have the power
to end life as we know it.
625
00:36:38,564 --> 00:36:45,202
♪
626
00:36:45,204 --> 00:36:49,439
narrator:
The milky way is around
100,000 light-years across,
627
00:36:49,441 --> 00:36:54,511
and it's home to at least
200 billion stars,
628
00:36:54,513 --> 00:36:58,048
but it hasn't
always been this large.
629
00:36:58,050 --> 00:37:01,418
We know that our milky way
galaxy grew to the size
630
00:37:01,420 --> 00:37:06,756
it is now, which is huge,
by eating other galaxies.
631
00:37:06,758 --> 00:37:09,059
And some of these galaxies
would've had
632
00:37:09,061 --> 00:37:11,561
supermassive black holes
in their centers.
633
00:37:14,199 --> 00:37:16,866
Narrator:
When the milky way's gravity
634
00:37:16,868 --> 00:37:18,668
pulled in smaller galaxies,
635
00:37:18,670 --> 00:37:23,807
most of their material
merged with the milky way,
636
00:37:23,809 --> 00:37:25,976
but some material like stars,
637
00:37:25,978 --> 00:37:29,446
could've been slung tens
of thousands of light-years
638
00:37:29,448 --> 00:37:31,081
out of the milky way.
639
00:37:33,385 --> 00:37:36,886
This could've happened
to a smaller galaxy's
640
00:37:36,888 --> 00:37:39,789
super massive black hole.
641
00:37:39,791 --> 00:37:41,458
Plait: It is entirely possible
642
00:37:41,460 --> 00:37:43,526
there are supermassive
black holes
643
00:37:43,528 --> 00:37:46,963
wandering around out there,
not in the center.
644
00:37:49,401 --> 00:37:51,201
Thaller: So how could it be
possible that there's actually
645
00:37:51,203 --> 00:37:53,970
a supermassive black hole
close to us wandering around,
646
00:37:53,972 --> 00:37:55,739
but we never even see it?
647
00:37:55,741 --> 00:37:59,209
Well, remember black hole
means it's really, really black.
648
00:37:59,211 --> 00:38:02,045
It actually absorbs radiation
and any energy.
649
00:38:02,047 --> 00:38:04,481
So unless something is falling
into a black hole
650
00:38:04,483 --> 00:38:08,385
or orbiting around it,
you're not going to see it.
651
00:38:08,387 --> 00:38:09,953
Tremblay: And so, if this
supermassive black hole
652
00:38:09,955 --> 00:38:13,256
were hypothetically wandering
the outskirts of our galaxy,
653
00:38:13,258 --> 00:38:15,225
well, there's a lot less
gas there
654
00:38:15,227 --> 00:38:16,926
for that black hole to run into.
655
00:38:16,928 --> 00:38:18,128
And if there's no gas around
656
00:38:18,130 --> 00:38:20,530
that black hole,
we will not see it.
657
00:38:22,668 --> 00:38:26,102
Narrator: The rogue supermassive
black hole may not stay
658
00:38:26,104 --> 00:38:29,005
in the outskirts
of the galaxy forever.
659
00:38:29,007 --> 00:38:32,642
Gravitational interactions
slowly pull it back
660
00:38:32,644 --> 00:38:34,644
into the milky way.
661
00:38:34,646 --> 00:38:36,446
Billions of years later,
662
00:38:36,448 --> 00:38:41,217
the supermassive black hole
could arrive in the center.
663
00:38:45,557 --> 00:38:48,692
When this rogue supermassive
black hole meets up with
664
00:38:48,694 --> 00:38:53,530
sagittarius a-star,
the fuse is lit.
665
00:38:55,167 --> 00:38:57,634
The pair spiral
towards each other...
666
00:39:00,906 --> 00:39:02,872
...Spinning faster and faster,
667
00:39:02,874 --> 00:39:05,442
reaching up to half
the speed of light.
668
00:39:05,444 --> 00:39:10,680
♪
669
00:39:10,682 --> 00:39:14,517
finally,
the two black holes merge.
670
00:39:14,519 --> 00:39:20,790
♪
671
00:39:20,792 --> 00:39:21,991
tremblay: You would have
672
00:39:21,993 --> 00:39:24,160
an enormously energetic event
on your hands.
673
00:39:24,162 --> 00:39:26,663
Those supermassive black holes
could, in principle,
674
00:39:26,665 --> 00:39:30,533
merge together, create a huge
blast of gravitational waves,
675
00:39:30,535 --> 00:39:34,371
accompanied by a profoundly
energetic flash of light
676
00:39:34,373 --> 00:39:37,040
that could, in principle,
endanger all life on earth.
677
00:39:37,042 --> 00:39:43,146
♪
678
00:39:43,148 --> 00:39:45,648
plait:
It's literally a stretching
679
00:39:45,650 --> 00:39:47,817
and contracting of space itself.
680
00:39:47,819 --> 00:39:50,053
It's like grabbing
the framework of space
681
00:39:50,055 --> 00:39:51,921
and it's shaking it really hard.
682
00:39:51,923 --> 00:39:53,890
And if this happens
in our galaxy,
683
00:39:53,892 --> 00:39:59,028
the amount of energy emitted,
that would be bad.
684
00:40:01,099 --> 00:40:03,299
Narrator:
When the black holes collide,
685
00:40:03,301 --> 00:40:04,634
they release more energy
686
00:40:04,636 --> 00:40:08,671
than all the stars
in the galaxy combined.
687
00:40:08,673 --> 00:40:15,478
♪
688
00:40:15,480 --> 00:40:17,847
plait: Should we be panicked
about this?
689
00:40:17,849 --> 00:40:19,249
And the answer is no.
690
00:40:19,251 --> 00:40:21,184
The earth has been orbiting
the sun
691
00:40:21,186 --> 00:40:23,887
for 4 1/2 billion years
without any incident, right?
692
00:40:23,889 --> 00:40:26,523
We're pretty safe from them.
693
00:40:26,525 --> 00:40:30,660
Narrator: If we were around to
see the two black holes collide,
694
00:40:30,662 --> 00:40:33,396
we'd witness the most
destructive light show
695
00:40:33,398 --> 00:40:35,331
in the history of the galaxy.
696
00:40:38,003 --> 00:40:43,339
But for now, the center of our
galaxy is relatively quiet,
697
00:40:43,341 --> 00:40:46,376
but it's still
a terrible place to be.
698
00:40:49,915 --> 00:40:53,049
The center of our milky way
is not a friendly place.
699
00:40:53,051 --> 00:40:56,820
It's nowhere you want to be.
It's a bad neighborhood.
700
00:40:56,822 --> 00:41:00,924
You've got tons of stars,
tons of radiation,
701
00:41:00,926 --> 00:41:05,028
and stars are being born
and dying and exploding.
702
00:41:05,030 --> 00:41:06,896
You've got the central
supermassive black hole.
703
00:41:06,898 --> 00:41:09,566
You've got a potential swarm
of black holes.
704
00:41:09,568 --> 00:41:12,001
You've got accretion disks.
You've got flares.
705
00:41:12,003 --> 00:41:16,105
You've got magnetic outbursts.
You've got jets.
706
00:41:16,107 --> 00:41:18,675
Let's just stay out here
in the suburbs, all right?
707
00:41:20,812 --> 00:41:22,145
Narrator:
The center of our galaxy
708
00:41:22,147 --> 00:41:25,815
is one of the most nightmarish
places in the cosmos.
709
00:41:28,620 --> 00:41:32,021
It's also home to some
of the most incredible forces
710
00:41:32,023 --> 00:41:33,723
the universe has to offer.
711
00:41:36,528 --> 00:41:39,195
Whatever the future
holds for our galaxy...
712
00:41:41,600 --> 00:41:46,870
...The core of the milky way
will be at the center of it all.
713
00:41:46,872 --> 00:41:50,406
Our home galaxy, the milky way,
is our safe harbor,
714
00:41:50,408 --> 00:41:53,776
our island in this vast,
cosmic ocean.
715
00:41:53,778 --> 00:41:56,779
And so to understand
the heart of our galaxy,
716
00:41:56,781 --> 00:42:00,517
is to understand our home
in this cosmic void.
64265
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