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Narrator:
Black holes --
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long considered
the bullies of the cosmos,
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but are they really so bad?
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Black holes aren't violent.
They are elegant.
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They're incredibly
powerful objects,
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but they're beautifully simple.
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Narrator:
Simple but unpredictable.
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Black holes rip planets
to shreds,
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but they also
give birth to stars.
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Black holes are like
the ultimate
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recycling-trash-bin
combination.
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Narrator:
They build galaxies
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and may have lit up
the dark infant universe.
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Tegmark: It's one of the biggest
changes that happened.
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Someone switched the lights on
and transforms our universe.
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Narrator:
They come in all sizes,
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from microscopic
to ultramassive,
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controlling the fate
of everything around them.
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Thaller: The story of the
universe and how it's arranged
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is the story of black holes.
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Narrator:
Black holes are the master
architects of the universe,
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and without them,
we would not exist.
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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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narrator:
Black holes --
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we're riveted
by their destructive power.
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Black holes are dangerous.
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Black holes are hazards.
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Black holes are not friendly
for their environments.
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There's just no good end
to anything
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that falls into a black hole.
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Perhaps one of the most
frightening objects
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in the universe.
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Narrator: But what exactly are
these scary objects?
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Black holes are created
when you get enough matter
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in a small region of space.
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Narrator: This happens
when a massive star dies
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and collapses in on itself...
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...a supernova.
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A black hole is the ultimate
consequence of gravity.
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It's an object
that has so much mass
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crushed into such a small space
that its escape velocity
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becomes greater
than the speed of light.
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Sutter:
They are a one-way street.
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You go in.
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Nothing escapes, not even light.
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Narrator: But do black holes
really deserve their bad rap?
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Thaller: In some ways,
I think we set up black holes
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to be more villains
than they actually are.
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Black holes suffer a bit
of a p.R. Problem.
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I think they're a lot more
menacing in science fiction
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and popular media
than they really are.
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��
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narrator: There are trillions of
galaxies in the known universe.
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And most of them have
a supermassive black hole
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at their center.
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These monsters are millions
of times the mass of our sun.
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Their immense gravity
can send stars flying.
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They're instrumental
in choreographing
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the dance of stars
in their vicinity.
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Narrator: Supermassive
black holes shoot out torrents
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of lethal radiation
and violent cosmic winds
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and gobble up anything
that comes close.
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Now scientists are beginning
to realize these cosmic giants
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may also have a creative side.
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Most people think
of black holes
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as being like giant
vacuum cleaners in space,
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and basically everything
falls into them,
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but that's not
actually the case.
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They're better thought of
as the engines of cosmic change.
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Natarajan: Although black holes
are the end states of stars,
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they can actually influence
the formation of stars,
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as well, in a bunch
of different ways.
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Narrator: A galaxy's job
is to make stars,
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but uncontrolled star growth
isn't healthy.
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Too many stars can drain
a galaxy's gas supply.
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Black holes
are very important.
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It appears that galaxy evolution
is tied to black-hole evolution.
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We don't know exactly how yet,
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but the marriage
appears certain.
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Narrator: One idea is that
supermassive black holes
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act as cosmic
control mechanisms.
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Black holes can act like
a thermostat in your house.
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If your house gets too hot,
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the thermostat will kick on
the air conditioner,
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and if it gets too cold,
it'll kick on the heater.
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Black holes do the same things
for galaxies.
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Narrator:
Supermassive black holes
regulate star formation
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by pulling gas in and shooting
it back out into the galaxy.
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When these black holes
are consuming matter,
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they're drawing matter
into themselves,
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but they're also
spewing stuff out.
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Basically, black holes eat
like little babies --
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very sloppily,
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so a lot of what they eat
comes flying back out again.
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Oluseyi: They eat stars.
They eat planets.
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But most often,
they eat giant clouds of gas.
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Narrator: The black hole drags
gas and dust
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into an accretion disk
around it.
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This disk spins faster
and faster.
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Magnetic energy builds up.
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With the accretion disk
swirling around the black hole,
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there are also magnetic fields
that are going on.
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The material is moving
so rapidly
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that the magnetic field
sort of winds up, coils up,
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and forms a vortex
like a tornado.
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Astronomers call them jets.
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��
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these jets propagate outward
like freight trains
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plowing through the galaxy
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over hundreds and thousands
of light-years.
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These are like death rays.
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Narrator: The jets disrupt
the star-forming gas clouds,
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limiting excess star formation
in the main body of the galaxy,
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but in the very outer reaches
of the galaxy,
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they can spark star birth.
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Things are more gentle
out there.
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You're not as close
to the energetic heart,
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so stars, planets, and life
can form out there
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partially because of
the material
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that the black hole
has moved out there.
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Natarajan: So black holes can
have outsize influence
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on the regions
that they inhabit.
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Right around them, they can
prevent the formation of stars
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whereas,
on very, very large scales,
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they can actually instigate
the formation of stars.
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Narrator: 2018 -- black holes
hit the front page.
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��
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scientists discovered
black holes gobbling up gas
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so fast that they seem to be
outgrowing their host galaxies.
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It naturally makes
the question come up --
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how big can a black hole get?
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Narrator:
Now we have the answer.
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They can reach size triple-xl,
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becoming ultramassive
black holes.
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stricker: Ultramassive
black holes are so cool
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because it's just mind-boggling
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that black holes so large
can exist.
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Mingarelli: Ultramassive
black holes are very rare
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and typically have masses
of more than 10 billion times
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the mass of the sun.
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Narrator:
10 billion solar masses --
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that's a 10
followed by nine zeros.
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Ultramassive black holes
are real beasts.
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The black hole at the center
of our galaxy
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is 4 million solar masses.
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Imagine black holes
that are 2,500 times bigger.
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That's what
we're talking about here.
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Narrator: An ultramassive
black hole this big
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would be as wide
as the solar system...
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...and weigh as much as
all the stars in the milky way.
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They're inside galaxies
that aren't a whole lot bigger.
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That really surprised the hell
out of everybody.
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Narrator: And in 2018,
scientists discover
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a 20-billion-solar-mass
ultramassive black hole
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growing faster
than any other black hole.
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This ravenous behemoth devours
the mass of our sun
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every two days.
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Bullock: These big black holes
are really good
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at gobbling up other things.
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They'll literally eat
anything.
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They're monsters
of the universe.
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Narrator:
This kind of voracious eating
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can have
devastating consequences.
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It blasts so much energy
and turbulence into the galaxy
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that stars no longer form,
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and the bigger the black hole,
the faster the galaxy dies.
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The primary thing these
ultramassive black holes
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do to galaxies is they shut down
all star formation,
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and so in that sense,
they kind of kill galaxies.
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Oluseyi:
And so these things
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could even wipe out
their host galaxies.
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Narrator:
Ultramassive black holes are
a problem for scientists, too.
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They might be
the fastest eaters,
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but that doesn't explain
how they got so large.
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With these ultramassive
black holes,
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these black holes that are
10s of billions of times
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more massive than our sun,
you can't just grow them
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from the slow accretion
of gas over time.
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There's just not enough gas,
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and there's just
not enough time.
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Bullock: It gives us
a new mystery to solve.
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How do you make black holes
that are just that big?
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There's not a clear answer
so far
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as to how these ultramassive
black holes were formed.
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People wonder if there's
some other mechanism
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by which you could make
black holes.
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Narrator: A mechanism so violent
it also throws
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supermassive black holes
clean out of galaxies.
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��
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��
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narrator: We now know that
ultramassive black holes
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billions of times
the mass of the sun exist,
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but we have no idea
how they got so big.
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We've detected
lightweight stellar-mass
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black holes colliding.
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They merged into a new
larger black hole
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and generated
huge amounts of energy.
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But what about
supermassive black holes?
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When galaxies merge,
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their central
supermassive black holes
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will fall to the center
of the newly formed galaxy.
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Narrator: Could these
supermassive black holes
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caught up in galactic mergers
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combine to form
an ultramassive black hole?
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��
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in 2017, the hubble
space telescope spotted
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something strange in
a distant galaxy called 3c186.
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It detected
an incredibly bright spot
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thousands of light-years
from the galaxy center.
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Scientists suspect
it's a quasar.
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A quasar is an incredibly
bright, active galactic nucleus
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that's powered by
a supermassive black hole.
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Narrator: We regularly spot
black-hole-powered quasars,
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but always at the centers
of galaxies,
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until now.
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When we actually got
this data from hubble,
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we were absolutely stunned
to discover
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that the quasar that
we've long known to exist
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in the center of this galaxy
wasn't actually at the center.
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This black hole is offset
from the center of the galaxy
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by about 35,000 light-years.
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That's really weird.
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Tremblay: What is an incredibly
rare and bizarre event
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to find a quasar,
a supermassive black hole,
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that is not
at the center of the galaxy.
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Narrator: When scientists
looked closer,
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they discovered that the quasar
is hurtling through space
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away from the center
of the galaxy.
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Now, mind you,
this is a black hole
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with the mass of about
a billion times the sun,
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00:13:50,896 --> 00:13:55,700
and it's screaming away
at 4 million miles an hour.
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Tremblay:
This black hole,
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which was probably originally
in the galaxy center,
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00:13:59,506 --> 00:14:02,439
has somehow been shot out
at high velocity
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00:14:02,441 --> 00:14:05,243
by some incredibly
violent event.
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00:14:05,245 --> 00:14:07,645
It's hard to imagine
what kind of event
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00:14:07,647 --> 00:14:10,915
would pump that much energy
into such a huge object
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00:14:10,917 --> 00:14:14,118
to shoot it away
from the center of a galaxy.
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00:14:14,120 --> 00:14:18,055
Who kicked it out,
how, and why?
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00:14:18,057 --> 00:14:20,591
Narrator:
Scientists have an idea.
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00:14:20,593 --> 00:14:24,795
3c186 may be the remnant
of a galaxy merger.
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00:14:24,797 --> 00:14:28,132
Narrator: The merged galaxies'
supermassive black holes
247
00:14:28,134 --> 00:14:30,534
circle each other,
248
00:14:30,536 --> 00:14:35,106
sending out blasts of energy in
the form of gravitational waves.
249
00:14:38,745 --> 00:14:42,012
Gravitational waves
are all around us.
250
00:14:42,014 --> 00:14:46,350
They're ripples in the fabric
of space-time.
251
00:14:46,352 --> 00:14:48,352
Every time mass moves,
252
00:14:48,354 --> 00:14:50,487
gravitational waves
are produced,
253
00:14:50,489 --> 00:14:55,025
so if I wave my hand,
I am making gravitational waves.
254
00:14:55,027 --> 00:15:00,198
Narrator: A hand produces
imperceptible waves.
255
00:15:00,200 --> 00:15:01,632
When objects as huge
256
00:15:01,634 --> 00:15:05,435
as supermassive black holes
collide,
257
00:15:05,437 --> 00:15:08,773
the energy released
as gravitational waves
258
00:15:08,775 --> 00:15:12,109
is phenomenal.
259
00:15:12,111 --> 00:15:14,244
Scientists think
these black holes
260
00:15:14,246 --> 00:15:17,581
might have been different sizes.
261
00:15:17,583 --> 00:15:19,650
It's possible that
if one of the black holes
262
00:15:19,652 --> 00:15:20,717
is really massive
263
00:15:20,719 --> 00:15:22,652
and the other one
isn't quite as massive,
264
00:15:22,654 --> 00:15:25,255
that when they spiral around
and merge,
265
00:15:25,257 --> 00:15:28,726
they send out gravitational
waves in an asymmetric way.
266
00:15:28,728 --> 00:15:35,399
��
267
00:15:35,401 --> 00:15:38,469
narrator: This asymmetry has
a catastrophic effect.
268
00:15:41,474 --> 00:15:44,074
As the two black holes collide
and merge,
269
00:15:44,076 --> 00:15:47,545
they shoot out a huge blast
of gravitational waves,
270
00:15:47,547 --> 00:15:49,847
but only in one direction.
271
00:15:52,151 --> 00:15:56,353
This blast of energy kicks
the newly combined black hole
272
00:15:56,355 --> 00:15:59,490
out of the galactic center.
273
00:15:59,492 --> 00:16:03,327
Think of a shotgun recoil,
but supersized.
274
00:16:05,498 --> 00:16:08,031
Plait: And there's so much
energy in that emission
275
00:16:08,033 --> 00:16:09,433
that it acts like a rocket,
276
00:16:09,435 --> 00:16:12,636
and it actually pushes
the merged black hole away.
277
00:16:12,638 --> 00:16:14,705
It would have been one of
the most energetic events
278
00:16:14,707 --> 00:16:16,574
ever witnessed.
279
00:16:16,576 --> 00:16:18,242
Plait:
They're so energetic,
280
00:16:18,244 --> 00:16:21,479
they are literally shaking
the fabric of space.
281
00:16:25,184 --> 00:16:28,452
Narrator: We didn't witness
the actual collision,
282
00:16:28,454 --> 00:16:31,855
but 3c186 could be evidence
283
00:16:31,857 --> 00:16:37,061
that supermassive black holes
can collide and merge,
284
00:16:37,063 --> 00:16:41,198
building even larger
black holes.
285
00:16:41,200 --> 00:16:43,734
This would be a mechanism
by which you would create,
286
00:16:43,736 --> 00:16:47,004
ultimately,
an ultramassive black hole.
287
00:16:47,006 --> 00:16:49,206
Narrator: As for the ejected
black hole,
288
00:16:49,208 --> 00:16:52,209
the gravitational recoil sent it
289
00:16:52,211 --> 00:16:56,013
on a one-way ride to oblivion.
290
00:16:56,015 --> 00:17:00,350
So gravitational waves kicked
this supermassive black hole
291
00:17:00,352 --> 00:17:02,219
and sent it
flying through space.
292
00:17:02,221 --> 00:17:07,024
In 20 million years, it's
expected to exit its galaxy.
293
00:17:07,026 --> 00:17:09,760
Narrator: The ejected
supermassive black hole
294
00:17:09,762 --> 00:17:12,363
may eventually hit
another galaxy
295
00:17:12,365 --> 00:17:16,100
and merge with
its supermassive black hole.
296
00:17:16,102 --> 00:17:22,105
��
297
00:17:22,107 --> 00:17:23,974
these largest of black holes
298
00:17:23,976 --> 00:17:26,844
seem to throw their weight
around,
299
00:17:26,846 --> 00:17:31,649
bullying galaxies
and other black holes.
300
00:17:31,651 --> 00:17:35,919
Now researchers have discovered
a vampire black hole
301
00:17:35,921 --> 00:17:39,389
that's draining the lifeblood
of its neighbor.
302
00:17:39,391 --> 00:17:43,794
��
303
00:17:50,402 --> 00:18:00,411
��
304
00:18:00,413 --> 00:18:02,346
narrator:
Ultramassive black holes
305
00:18:02,348 --> 00:18:05,148
seem to destroy their galaxies,
306
00:18:05,150 --> 00:18:10,888
while supermassive black holes
seem to regulate star formation.
307
00:18:10,890 --> 00:18:15,559
But are all supermassive
black holes forces for good?
308
00:18:15,561 --> 00:18:20,864
��
309
00:18:20,866 --> 00:18:25,370
hundreds of galaxies
surround the milky way,
310
00:18:25,372 --> 00:18:28,571
large and small,
311
00:18:28,573 --> 00:18:33,844
but most of
the largest galaxies are red.
312
00:18:33,846 --> 00:18:35,979
This is not a good omen.
313
00:18:35,981 --> 00:18:39,350
In space, red means danger.
314
00:18:41,520 --> 00:18:43,721
If you have active
ongoing star birth,
315
00:18:43,723 --> 00:18:45,055
then you have massive stars,
316
00:18:45,057 --> 00:18:46,856
and massive stars
tend to be blue,
317
00:18:46,858 --> 00:18:49,226
but they don't live very long,
and they blow up.
318
00:18:53,132 --> 00:18:55,665
Once you stop star formation,
after some amount of time,
319
00:18:55,667 --> 00:18:59,336
the galaxy turns red.
320
00:18:59,338 --> 00:19:01,137
Narrator:
The only stars left alive
321
00:19:01,139 --> 00:19:06,944
are small, long-lived red stars
called red dwarfs.
322
00:19:06,946 --> 00:19:10,414
A red galaxy with only
red dwarfs
323
00:19:10,416 --> 00:19:13,750
is a dying galaxy.
324
00:19:13,752 --> 00:19:17,420
The Sloan digital sky survey
found an entire population
325
00:19:17,422 --> 00:19:20,557
of these luminous red galaxies
326
00:19:20,559 --> 00:19:22,961
that were no longer
forming stars
327
00:19:22,963 --> 00:19:23,994
that were dead.
328
00:19:26,899 --> 00:19:31,602
Narrator:
One galaxy around 340 million
light-years away stood out.
329
00:19:35,440 --> 00:19:40,444
It was named after a Japanese
anime character, Akira.
330
00:19:40,446 --> 00:19:42,046
Plait:
It's very red.
331
00:19:42,048 --> 00:19:44,514
All the stars in it are red,
and that means they're old,
332
00:19:44,516 --> 00:19:45,983
so we know that Akira
has not had
333
00:19:45,985 --> 00:19:48,452
any active star formation
in a long time.
334
00:19:51,390 --> 00:19:53,323
Narrator: The Akira galaxy
doesn't form stars
335
00:19:53,325 --> 00:19:55,793
because it doesn't have
the cool, calm gas
336
00:19:55,795 --> 00:19:57,061
needed to build them.
337
00:19:59,264 --> 00:20:02,933
Something is heating the gas,
making it turbulent.
338
00:20:05,004 --> 00:20:07,337
One of the ways in which
a black hole can drive
339
00:20:07,339 --> 00:20:09,806
the evolution of the galaxy
in which it resides
340
00:20:09,808 --> 00:20:13,410
is by simply powering a wind.
341
00:20:13,412 --> 00:20:16,714
These are winds that are
literally driven by light.
342
00:20:19,551 --> 00:20:21,151
Narrator:
When a black hole feeds,
343
00:20:21,153 --> 00:20:25,889
it drags gas
into an accretion disk.
344
00:20:25,891 --> 00:20:29,326
The disk heats up
and gives off light radiation.
345
00:20:31,763 --> 00:20:35,432
The radiation pressure
from the accretion disk
around this black hole
346
00:20:35,434 --> 00:20:37,767
couples to
the ambient gas and dust
347
00:20:37,769 --> 00:20:42,040
and pushes it outwards
at very high velocity.
348
00:20:42,042 --> 00:20:45,976
These winds that are driven
out by the black hole
349
00:20:45,978 --> 00:20:49,779
essentially warm up the gas
in the galaxy,
350
00:20:49,781 --> 00:20:52,349
preventing further
star formation.
351
00:20:54,453 --> 00:20:58,121
Narrator: However, whatever's
fueling the black hole in Akira
352
00:20:58,123 --> 00:20:59,990
is a mystery.
353
00:20:59,992 --> 00:21:02,793
Here's a weird thing --
there is an outflow,
354
00:21:02,795 --> 00:21:04,928
a wind coming out
of this galaxy,
355
00:21:04,930 --> 00:21:06,864
and that means
there's gas feeding
356
00:21:06,866 --> 00:21:10,000
that black hole in the center,
and it's blowing it out.
357
00:21:10,002 --> 00:21:13,604
Where is this gas coming from?
358
00:21:13,606 --> 00:21:16,606
Ah, it's stealing it.
359
00:21:16,608 --> 00:21:20,344
It has a small companion galaxy,
which is nicknamed tetsuo,
360
00:21:20,346 --> 00:21:22,080
and that has gas in it.
361
00:21:24,950 --> 00:21:29,219
Narrator: Akira's supermassive
black hole pulls gas from tetsuo
362
00:21:29,221 --> 00:21:31,923
and drags it
into the center of the galaxy.
363
00:21:34,827 --> 00:21:38,094
The black hole is taking the gas
from this companion galaxy,
364
00:21:38,096 --> 00:21:39,897
and that's what's falling
around the black hole
365
00:21:39,899 --> 00:21:41,632
and creating this wind,
366
00:21:41,634 --> 00:21:44,234
so Akira is actually
sort of a dead galaxy,
367
00:21:44,236 --> 00:21:47,404
but it's being rejuvenated
by its companion, tetsuo.
368
00:21:50,976 --> 00:21:52,844
Narrator:
Like a cosmic vampire,
369
00:21:52,846 --> 00:21:57,514
Akira's supermassive black hole
feeds off tetsuo.
370
00:22:00,053 --> 00:22:04,521
The black hole drags gas and
dust into its accretion disk,
371
00:22:04,523 --> 00:22:08,525
which spins faster and faster.
372
00:22:08,527 --> 00:22:10,793
Plait: When these particles
are rubbing against each other,
373
00:22:10,795 --> 00:22:13,131
well, that generates friction.
374
00:22:13,133 --> 00:22:15,532
Friction may not seem like
that big of a deal.
375
00:22:15,534 --> 00:22:16,800
I mean, you can rub
your hands together
376
00:22:16,802 --> 00:22:18,535
on a cold day to get warm,
377
00:22:18,537 --> 00:22:20,070
but imagine rubbing
your hands together
378
00:22:20,072 --> 00:22:22,472
at very nearly
the speed of light.
379
00:22:22,474 --> 00:22:24,074
How much friction is
that gonna generate?
380
00:22:24,076 --> 00:22:27,076
It's gonna make a lot of heat.
381
00:22:27,078 --> 00:22:31,415
Narrator: Over a million degrees
fahrenheit --
382
00:22:31,417 --> 00:22:35,185
so hot the accretion disk
lights up.
383
00:22:38,024 --> 00:22:41,558
Its temperature goes up,
and he starts emitting light.
384
00:22:41,560 --> 00:22:44,494
It becomes incredibly bright.
385
00:22:44,496 --> 00:22:46,563
Even though there's a black hole
in the core,
386
00:22:46,565 --> 00:22:51,902
its surroundings
are intensely bright.
387
00:22:51,904 --> 00:22:54,338
Narrator: This heats up
the surrounding gas,
388
00:22:54,340 --> 00:22:56,239
generating a hot wind,
389
00:22:56,241 --> 00:23:01,444
which extends thousands of
light-years from the black hole.
390
00:23:01,446 --> 00:23:04,515
Tremblay: And those winds carry
with them a lot of energy,
391
00:23:04,517 --> 00:23:08,051
and that energy, if it couples
to the gas in the galaxy,
392
00:23:08,053 --> 00:23:10,053
can blow that gas out.
393
00:23:10,055 --> 00:23:12,455
They inject energy
into nearby gas clouds
394
00:23:12,457 --> 00:23:17,127
and heat them up and prevent
them from forming stars.
395
00:23:17,129 --> 00:23:20,731
Narrator: Stars don't form --
the galaxy dies.
396
00:23:23,335 --> 00:23:26,870
These dying galaxies
are called red geysers.
397
00:23:30,476 --> 00:23:33,810
Scientists think around 10%
of the red galaxies
398
00:23:33,812 --> 00:23:37,014
we see around us
died this way...
399
00:23:39,352 --> 00:23:42,386
...heated up
by this galactic warming.
400
00:23:45,156 --> 00:23:48,158
We think that the source
of some of this galactic warming
401
00:23:48,160 --> 00:23:50,961
is in the growth of supermassive
black holes themselves
402
00:23:50,963 --> 00:23:53,297
because when you grow
a supermassive black hole,
403
00:23:53,299 --> 00:23:56,833
you must liberate
an enormous amount of energy.
404
00:23:56,835 --> 00:23:59,503
You can't grow a black hole
for free,
405
00:23:59,505 --> 00:24:03,240
and that energy gets dumped back
into the ambient surroundings
406
00:24:03,242 --> 00:24:05,175
and keeps this halo of gas hot.
407
00:24:05,177 --> 00:24:08,012
It prevents it from cooling
and forming stars.
408
00:24:11,450 --> 00:24:13,317
Narrator:
Sagittarius a-star,
409
00:24:13,319 --> 00:24:16,919
the supermassive black hole
at the heart of our galaxy,
410
00:24:16,921 --> 00:24:21,525
the milky way,
could turn into a red geyser.
411
00:24:21,527 --> 00:24:24,528
If you were suddenly to dump
an enormous amount of gas
412
00:24:24,530 --> 00:24:26,463
onto sagittarius a-star,
413
00:24:26,465 --> 00:24:29,199
you could have what is
effectively a red-geyser effect,
414
00:24:29,201 --> 00:24:33,203
a very powerful wind
driven by all of this energy.
415
00:24:37,475 --> 00:24:40,010
Narrator:
Star formation would stop,
416
00:24:40,012 --> 00:24:44,782
and our milky way would become
another dying red galaxy.
417
00:24:49,754 --> 00:24:53,690
Now new research suggests
that sagittarius a-star
418
00:24:53,692 --> 00:24:57,761
has already affected
the inner region of our galaxy,
419
00:24:57,763 --> 00:24:59,762
not by killing stars,
420
00:24:59,764 --> 00:25:05,269
but by transforming planets from
gas giants into super-earths.
421
00:25:05,271 --> 00:25:08,772
��
422
00:25:15,314 --> 00:25:20,517
��
423
00:25:20,519 --> 00:25:25,655
��
424
00:25:25,657 --> 00:25:27,390
narrator:
At the center of our galaxy
425
00:25:27,392 --> 00:25:32,295
lies a supermassive black hole,
sagittarius a-star.
426
00:25:35,467 --> 00:25:40,337
We think it's calm,
dormant, safe.
427
00:25:40,339 --> 00:25:42,405
Relative to other
supermassive black holes
428
00:25:42,407 --> 00:25:45,875
in the universe,
ours is relatively quiet.
429
00:25:45,877 --> 00:25:48,678
Narrator:
It's been active in the past,
430
00:25:48,680 --> 00:25:52,081
and it could flare up
in the future.
431
00:25:52,083 --> 00:25:54,350
Tremblay: It could be active
tomorrow, for all we know.
432
00:25:54,352 --> 00:25:55,952
All you need to do
to light it up
433
00:25:55,954 --> 00:25:58,088
is start dumping some gas on it,
434
00:25:58,090 --> 00:26:00,824
and there is almost certainly
a giant cloud of gas
435
00:26:00,826 --> 00:26:02,225
that we don't currently know of
436
00:26:02,227 --> 00:26:04,427
on its way
to the center of our galaxy,
437
00:26:04,429 --> 00:26:06,362
and it will find itself one day
in the vicinity
438
00:26:06,364 --> 00:26:07,965
of our supermassive black hole,
439
00:26:07,967 --> 00:26:11,701
and it will start to light up
like a Christmas tree.
440
00:26:11,703 --> 00:26:16,040
Narrator: In February of 2018,
scientists at Harvard
441
00:26:16,042 --> 00:26:20,910
simulated sagittarius a-star
during a feeding frenzy
442
00:26:20,912 --> 00:26:25,381
to understand the impact of an
active supermassive black hole
443
00:26:25,383 --> 00:26:26,917
on its local environment.
444
00:26:30,722 --> 00:26:31,854
They found that,
445
00:26:31,856 --> 00:26:35,058
as sagittarius a-star
gobbled up gas and dust,
446
00:26:35,060 --> 00:26:40,930
it belched out bright flares
of high-energy radiation,
447
00:26:40,932 --> 00:26:45,936
which radically affected the
region around the black hole.
448
00:26:45,938 --> 00:26:48,605
Plait: The environment near
the center of a galaxy
449
00:26:48,607 --> 00:26:51,007
that has an actively
feeding black hole
450
00:26:51,009 --> 00:26:53,943
is the worst place
in the universe.
451
00:26:53,945 --> 00:26:55,946
You've got
this tremendous object
452
00:26:55,948 --> 00:26:59,483
which is heating up this gas
to millions of degrees.
453
00:26:59,485 --> 00:27:01,818
This is no place
that you want to be.
454
00:27:04,822 --> 00:27:06,857
Narrator: The model revealed
what would happen
455
00:27:06,859 --> 00:27:10,360
to any planets
in the line of fire.
456
00:27:10,362 --> 00:27:11,427
Thaller:
Think about being in the way
457
00:27:11,429 --> 00:27:13,896
of one of these
black-hole burps.
458
00:27:13,898 --> 00:27:16,499
All of a sudden, there's
a tremendous wind of radiation
459
00:27:16,501 --> 00:27:18,167
that comes through
your solar system.
460
00:27:18,169 --> 00:27:21,103
That could actually strip away
the outer layers of gas
461
00:27:21,105 --> 00:27:22,572
of a planet like Neptune.
462
00:27:25,310 --> 00:27:26,709
Narrator:
The high-energy radiation
463
00:27:26,711 --> 00:27:28,845
from the supermassive
black holes
464
00:27:28,847 --> 00:27:33,317
would hit the gas planets
and heat up their atmospheres.
465
00:27:33,319 --> 00:27:35,919
Thaller:
Maybe this would actually
strip away the outer layers,
466
00:27:35,921 --> 00:27:38,054
leaving the solid material
in the middle.
467
00:27:38,056 --> 00:27:40,256
You could actually turn
a gas-giant planet
468
00:27:40,258 --> 00:27:42,325
into a terrestrial solid planet
469
00:27:42,327 --> 00:27:46,062
all because you're close
to a black hole.
470
00:27:46,064 --> 00:27:50,734
Narrator:
This radiation strips away
the gas, leaving the core,
471
00:27:50,736 --> 00:27:54,137
now a new rocky planet
472
00:27:54,139 --> 00:27:58,074
but a giant one --
a super-earth.
473
00:27:58,076 --> 00:27:59,977
Normally, you think
of rocky planets
474
00:27:59,979 --> 00:28:01,745
being about the size
of the earth,
475
00:28:01,747 --> 00:28:05,882
but this would be a way of
making so called super-earths.
476
00:28:05,884 --> 00:28:07,884
Narrator: Super-earths are
one of the most common
477
00:28:07,886 --> 00:28:11,888
type of planets
discovered in our galaxy.
478
00:28:11,890 --> 00:28:14,291
It's possible
that any super-earths
479
00:28:14,293 --> 00:28:16,626
close to sagittarius a-star
480
00:28:16,628 --> 00:28:19,729
were created
by these blasts of energy.
481
00:28:23,969 --> 00:28:26,235
Away from our galactic center,
482
00:28:26,237 --> 00:28:29,706
a much smaller
stellar-mass black hole
483
00:28:29,708 --> 00:28:33,143
is also radically transforming
its environment.
484
00:28:36,114 --> 00:28:38,715
January 2017 --
485
00:28:38,717 --> 00:28:41,851
researchers discover
something strange
486
00:28:41,853 --> 00:28:46,589
in a cloud of gas called w44.
487
00:28:46,591 --> 00:28:48,526
Plait:
W44 is a supernova remnant.
488
00:28:48,528 --> 00:28:53,797
It's the debris -- the expanding
cloud from a star that blew up.
489
00:28:53,799 --> 00:28:57,934
Narrator: The explosive
shock wave from a supernova
490
00:28:57,936 --> 00:29:01,671
pushes gas and dust
out from the dead star,
491
00:29:01,673 --> 00:29:05,275
forming a huge nebula.
492
00:29:05,277 --> 00:29:06,743
Plait:
We see a lot of these.
493
00:29:06,745 --> 00:29:09,280
I mean, they're catastrophic,
amazing, incredible events,
494
00:29:09,282 --> 00:29:10,480
but as far as they go,
495
00:29:10,482 --> 00:29:13,483
this one appears to be
pretty standard,
496
00:29:13,485 --> 00:29:15,752
except for one weird thing.
497
00:29:15,754 --> 00:29:16,952
Thaller:
In the heart of it,
498
00:29:16,954 --> 00:29:18,822
there's something
very mysterious going on.
499
00:29:18,824 --> 00:29:20,957
There seems to be something
shooting out
500
00:29:20,959 --> 00:29:23,493
of the very center
of this explosion.
501
00:29:23,495 --> 00:29:29,566
��
502
00:29:29,568 --> 00:29:32,435
narrator: A thin protrusion
trillions of miles long
503
00:29:32,437 --> 00:29:36,573
streams out from the cloud.
504
00:29:36,575 --> 00:29:39,241
It's moving at
over 60 miles a second
505
00:29:39,243 --> 00:29:42,779
against the flow of the galaxy.
506
00:29:42,781 --> 00:29:45,114
It's very strange
that it's moving backwards
507
00:29:45,116 --> 00:29:47,517
against the rotation
of the milky way.
508
00:29:47,519 --> 00:29:51,321
Tremblay: When you see a giant,
giant, very massive cloud of gas
509
00:29:51,323 --> 00:29:53,856
that is moving counter to
the rotation of the milky way,
510
00:29:53,858 --> 00:29:55,792
it needed to be like
a bullet from a gun
511
00:29:55,794 --> 00:29:59,395
fired against a headwind
in the opposite direction.
512
00:29:59,397 --> 00:30:00,797
So what is that gun?
513
00:30:00,799 --> 00:30:04,934
You know, what fired
that bullet of gas?
514
00:30:04,936 --> 00:30:07,404
Narrator: The tip of
the bullet cloud is expanding
515
00:30:07,406 --> 00:30:09,806
at 75 miles a second.
516
00:30:09,808 --> 00:30:12,809
That's 270,000 miles an hour,
517
00:30:12,811 --> 00:30:17,080
over 150 times faster
than a bullet.
518
00:30:17,082 --> 00:30:20,884
What in the cosmos has the power
to accelerate gas
519
00:30:20,886 --> 00:30:23,553
to such high speed?
520
00:30:23,555 --> 00:30:25,488
Could that actually be
a black hole
521
00:30:25,490 --> 00:30:28,491
moving very, very quickly?
522
00:30:28,493 --> 00:30:31,628
Narrator: Researchers think
a stellar-mass black hole
523
00:30:31,630 --> 00:30:33,296
hidden in the bullet cloud
524
00:30:33,298 --> 00:30:36,165
is powering
the movement of the gas.
525
00:30:36,167 --> 00:30:38,568
Gravity from this black hole
is incredibly strong,
526
00:30:38,570 --> 00:30:40,570
and so it will
latch onto this gas cloud
527
00:30:40,572 --> 00:30:42,038
as it passes through it,
528
00:30:42,040 --> 00:30:45,308
and it can completely disrupt
the motions of this cloud.
529
00:30:45,310 --> 00:30:47,711
Bullock: This is a very
interesting stream of gas
530
00:30:47,713 --> 00:30:50,246
that's somehow connected
to a black hole,
531
00:30:50,248 --> 00:30:51,581
and we don't know
whether it's there
532
00:30:51,583 --> 00:30:53,717
because the black hole
is moving through the gas,
533
00:30:53,719 --> 00:30:55,317
and it's creating a wake,
534
00:30:55,319 --> 00:30:57,520
or whether somehow
this black hole
535
00:30:57,522 --> 00:31:01,924
is spitting out a stream
of material in some way.
536
00:31:01,926 --> 00:31:03,927
Narrator: The black hole
could be dragging gas
537
00:31:03,929 --> 00:31:06,930
into an accretion disk
around it.
538
00:31:06,932 --> 00:31:09,199
The gas heats up and expands,
539
00:31:09,201 --> 00:31:15,538
giving the initial supernova
explosion, w44, an extra kick,
540
00:31:15,540 --> 00:31:19,942
driving this bullet-like cloud
out in front of it.
541
00:31:19,944 --> 00:31:23,613
Or the black hole could be
racing away from the nebula,
542
00:31:23,615 --> 00:31:27,082
dragging the gas behind it
like a wake.
543
00:31:27,084 --> 00:31:33,289
��
544
00:31:33,291 --> 00:31:37,827
ultramassive, supermassive,
and stellar-mass black holes
545
00:31:37,829 --> 00:31:41,564
all play a role
in shaping the cosmos,
546
00:31:41,566 --> 00:31:44,767
but there may be
another type of black hole
547
00:31:44,769 --> 00:31:49,105
even more dangerous
than the rest --
548
00:31:49,107 --> 00:31:51,841
a microscopic black hole.
549
00:31:51,843 --> 00:31:55,912
��
550
00:32:02,387 --> 00:32:09,058
��
551
00:32:09,060 --> 00:32:15,732
��
552
00:32:15,734 --> 00:32:18,735
narrator: We have so far
detected triple-xl
553
00:32:18,737 --> 00:32:24,206
ultramassive black holes,
large supermassive black holes,
554
00:32:24,208 --> 00:32:28,545
medium-sized
intermediate black holes,
555
00:32:28,547 --> 00:32:32,215
and small stellar-mass
black holes.
556
00:32:32,217 --> 00:32:36,419
Now scientists have another
to add to the roster --
557
00:32:36,421 --> 00:32:39,222
microscopic black holes.
558
00:32:39,224 --> 00:32:40,757
Carroll: We know there are
supermassive black holes
559
00:32:40,759 --> 00:32:42,626
at the centers of galaxies.
560
00:32:42,628 --> 00:32:45,228
We know there are
star-sized black holes
561
00:32:45,230 --> 00:32:46,562
from the deaths of stars.
562
00:32:46,564 --> 00:32:48,331
That's what we know for sure.
563
00:32:48,333 --> 00:32:50,900
It's possible there are
much smaller black holes,
564
00:32:50,902 --> 00:32:53,970
microscopically
small black holes.
565
00:32:53,972 --> 00:32:57,306
Narrator:
Microscopic black holes
are virtually invisible
566
00:32:57,308 --> 00:32:58,775
to the naked eye,
567
00:32:58,777 --> 00:33:04,648
but magnified, they look like
regular stellar-mass black holes
568
00:33:04,650 --> 00:33:06,983
the definition of a black hole
569
00:33:06,985 --> 00:33:09,385
is an object
that has so much mass
570
00:33:09,387 --> 00:33:12,756
crushed into such a small space
that its escape velocity
571
00:33:12,758 --> 00:33:14,924
becomes greater
than the speed of light,
572
00:33:14,926 --> 00:33:17,327
so it could be something
the size of a star,
573
00:33:17,329 --> 00:33:18,928
the size of a galaxy.
574
00:33:18,930 --> 00:33:21,998
It could also be
the mass of a planet.
575
00:33:22,000 --> 00:33:25,135
Narrator: If you could crush
the earth down far enough,
576
00:33:25,137 --> 00:33:27,670
it could become a black hole.
577
00:33:27,672 --> 00:33:28,938
Thaller:
The density of a black hole
578
00:33:28,940 --> 00:33:30,406
is something
that the human brain
579
00:33:30,408 --> 00:33:32,408
really doesn't wrap itself
around very easily.
580
00:33:32,410 --> 00:33:34,877
When you think about something
the size of the earth,
581
00:33:34,879 --> 00:33:37,547
how small would the earth
have to be to be a black hole?
582
00:33:37,549 --> 00:33:40,016
And the answer is something
on the order of a marble.
583
00:33:40,018 --> 00:33:41,884
So think about taking
the entire earth
584
00:33:41,886 --> 00:33:44,521
and compressing it down
to the size of just a marble.
585
00:33:46,958 --> 00:33:51,561
Narrator:
So where do these strange
little black holes come from?
586
00:33:51,563 --> 00:33:54,897
These very small black holes
can only be formed
587
00:33:54,899 --> 00:34:01,237
in the exotic conditions of
the incredibly early universe.
588
00:34:01,239 --> 00:34:04,173
Our universe might get flooded
with these small black holes
589
00:34:04,175 --> 00:34:09,112
that simply persist
to the present day.
590
00:34:09,114 --> 00:34:10,580
It's the only time
in the history of the universe
591
00:34:10,582 --> 00:34:12,448
where you could take
a small amount of matter
592
00:34:12,450 --> 00:34:13,983
and crush it down so tightly
593
00:34:13,985 --> 00:34:15,652
that it could become
a black hole.
594
00:34:15,654 --> 00:34:17,855
Those conditions don't exist
anymore,
595
00:34:17,857 --> 00:34:21,457
so if these things exist,
they would be primordial.
596
00:34:21,459 --> 00:34:24,060
They would be as old
as the universe itself.
597
00:34:24,062 --> 00:34:30,199
��
598
00:34:30,201 --> 00:34:33,603
narrator: These primordial
black holes may be ancient,
599
00:34:33,605 --> 00:34:36,806
but they still pack a punch.
600
00:34:36,808 --> 00:34:38,408
When it comes to black holes,
601
00:34:38,410 --> 00:34:42,344
the smaller black holes
are actually more dangerous
602
00:34:42,346 --> 00:34:44,480
because their mass
is concentrated
603
00:34:44,482 --> 00:34:47,149
into such a small volume.
604
00:34:47,151 --> 00:34:51,621
Narrator: In fact, a tiny
black hole would be lethal.
605
00:34:51,623 --> 00:34:55,091
If it were to pass
in front of me, very quickly,
606
00:34:55,093 --> 00:34:58,761
almost instantly, I would be
ripped apart head to toe,
607
00:34:58,763 --> 00:35:03,533
stretched into a long, thin
stream of fundamental particles
608
00:35:03,535 --> 00:35:06,302
that would then wind their way
into the black hole.
609
00:35:06,304 --> 00:35:12,041
It would actively feast on me
in a matter of seconds.
610
00:35:12,043 --> 00:35:15,445
Narrator: But if Paul
or an interstellar robotic probe
611
00:35:15,447 --> 00:35:17,780
visited a supermassive
black hole
612
00:35:17,782 --> 00:35:20,316
or even an ultramassive
black hole,
613
00:35:20,318 --> 00:35:25,121
they wouldn't be immediately
ripped to shreds.
614
00:35:25,123 --> 00:35:27,190
One of the most fun questions
about black holes is,
615
00:35:27,192 --> 00:35:29,125
how close could you get
to a black hole
616
00:35:29,127 --> 00:35:31,327
before the gravity
would rip you apart?
617
00:35:31,329 --> 00:35:34,597
And that actually depends
on the volume of the black hole.
618
00:35:34,599 --> 00:35:38,936
If the black hole is very large,
you could get very, very close.
619
00:35:38,938 --> 00:35:40,536
Bullock:
The more massive they are,
620
00:35:40,538 --> 00:35:43,806
the slightly softer they are
in how they tear things apart,
621
00:35:43,808 --> 00:35:45,876
so a supermassive black hole,
actually --
622
00:35:45,878 --> 00:35:48,077
you can cross within
the event horizon
623
00:35:48,079 --> 00:35:50,546
and not really notice it.
624
00:35:50,548 --> 00:35:52,015
You're never gonna get back out,
625
00:35:52,017 --> 00:35:54,149
but you won't necessarily
be stretched to your death
626
00:35:54,151 --> 00:35:55,818
while you cross inside.
627
00:35:58,556 --> 00:36:01,691
Narrator: So a probe could visit
a supermassive black hole
628
00:36:01,693 --> 00:36:03,426
and not be destroyed...
629
00:36:05,830 --> 00:36:08,230
...until it crossed
the event horizon
630
00:36:08,232 --> 00:36:10,533
and traveled deep inside.
631
00:36:12,637 --> 00:36:15,238
Then it would be torn to pieces.
632
00:36:17,642 --> 00:36:23,512
But microscopic black holes
are currently just a theory.
633
00:36:23,514 --> 00:36:26,782
Mingarelli: Microscopic
black holes have been the focus
634
00:36:26,784 --> 00:36:29,051
for some researchers
for many years,
635
00:36:29,053 --> 00:36:30,653
but currently
there's no evidence
636
00:36:30,655 --> 00:36:32,689
to support their existence.
637
00:36:35,527 --> 00:36:38,794
Narrator: Microscopic primordial
black holes may or may not
638
00:36:38,796 --> 00:36:41,364
have been around
since the big bang.
639
00:36:43,668 --> 00:36:48,137
Now scientists have discovered
supermassive black holes
640
00:36:48,139 --> 00:36:51,340
from the very early universe.
641
00:36:51,342 --> 00:36:56,412
They're shedding light on one of
the most mysterious eras,
642
00:36:56,414 --> 00:36:59,081
the cosmic dark ages.
643
00:36:59,083 --> 00:37:02,285
��
644
00:37:08,759 --> 00:37:16,700
��
645
00:37:16,702 --> 00:37:20,302
narrator: Black holes don't just
shape the universe now.
646
00:37:20,304 --> 00:37:24,273
They've been shaping it
from almost the dawn of time.
647
00:37:26,310 --> 00:37:29,044
Scientists think black holes
may have triggered
648
00:37:29,046 --> 00:37:32,115
one of the universe's
greatest transformations --
649
00:37:32,117 --> 00:37:37,186
turning from dark and foggy
to transparent and light.
650
00:37:37,188 --> 00:37:44,727
��
651
00:37:44,729 --> 00:37:46,329
at the beginning of time,
652
00:37:46,331 --> 00:37:50,500
the universe was a tiny ball
of super-hot energy --
653
00:37:50,502 --> 00:37:53,536
the big bang.
654
00:37:53,538 --> 00:37:57,406
Shortly after our big bang,
our universe was shining bright
655
00:37:57,408 --> 00:38:01,410
because it was full of
hot, glowing gas.
656
00:38:01,412 --> 00:38:05,082
Then it cooled off and entered
the so-called dark ages
657
00:38:05,084 --> 00:38:09,485
until eventually something
lit it up again.
658
00:38:09,487 --> 00:38:12,221
It's one of the biggest changes
that happened in our universe.
659
00:38:12,223 --> 00:38:17,492
Someone switched the lights on
and transformed the universe.
660
00:38:17,494 --> 00:38:18,895
Narrator:
During the dark ages,
661
00:38:18,897 --> 00:38:22,698
the universe was blanketed
in a thick fog.
662
00:38:22,700 --> 00:38:24,900
Then something lit it up
663
00:38:24,902 --> 00:38:29,305
in a process called
reionization.
664
00:38:29,307 --> 00:38:30,840
We still don't really know
for sure
665
00:38:30,842 --> 00:38:35,377
whether reionization
was mainly caused by young stars
666
00:38:35,379 --> 00:38:39,782
or whether it was mainly
black holes that ate stuff
667
00:38:39,784 --> 00:38:42,219
and spewed out
a bunch of radiation.
668
00:38:45,123 --> 00:38:48,458
Narrator:
Then in December of 2017,
669
00:38:48,460 --> 00:38:52,995
researchers in Chile scan
a region of space so far away
670
00:38:52,997 --> 00:38:58,267
it takes light
13 billion years to reach us.
671
00:38:58,269 --> 00:39:03,005
They spot an object
from just 690 million years
672
00:39:03,007 --> 00:39:04,606
after the big bang
673
00:39:04,608 --> 00:39:10,345
when the universe was only 5%
of its current age.
674
00:39:10,347 --> 00:39:16,652
It's called quasar j1342+0928.
675
00:39:19,757 --> 00:39:22,357
The thing that's so amazing
about this farthest quasar
676
00:39:22,359 --> 00:39:27,096
is we may actually have seen
the boundary of these dark ages.
677
00:39:27,098 --> 00:39:31,033
This particular supermassive
black hole/quasar tells us
678
00:39:31,035 --> 00:39:35,237
something about the formation
of the early universe.
679
00:39:35,239 --> 00:39:38,241
Narrator: It's thought that
quasars helped drag the universe
680
00:39:38,243 --> 00:39:40,309
out of the dark ages.
681
00:39:40,311 --> 00:39:42,845
They gobbled up
so much hydrogen gas
682
00:39:42,847 --> 00:39:46,650
and belched out jets of energy
683
00:39:46,652 --> 00:39:49,185
and cleared up the fog.
684
00:39:49,187 --> 00:39:51,988
Those jets could have actually
put so much energy
685
00:39:51,990 --> 00:39:55,257
into the universe
that it made it clear again.
686
00:39:55,259 --> 00:39:57,260
We may actually be seeing
the moment
687
00:39:57,262 --> 00:40:00,830
where something punches through
this boundary of the dark ages.
688
00:40:05,269 --> 00:40:07,670
Narrator: Pockets
of reionization opened up
689
00:40:07,672 --> 00:40:10,540
throughout the early universe.
690
00:40:10,542 --> 00:40:14,644
They came in different sizes,
depending on what created them.
691
00:40:17,415 --> 00:40:19,348
Tegmark: While our universe
was being reionized,
692
00:40:19,350 --> 00:40:21,417
there was kind of, like,
all these holes
693
00:40:21,419 --> 00:40:23,485
that kept growing.
694
00:40:23,487 --> 00:40:27,823
If the reionization was made by
a large number of little stars,
695
00:40:27,825 --> 00:40:29,759
you would have
many, many small holes,
696
00:40:29,761 --> 00:40:32,762
much like a sponge,
697
00:40:32,764 --> 00:40:36,098
whereas if you had
a small number
698
00:40:36,100 --> 00:40:37,501
of monster black holes doing it,
699
00:40:37,503 --> 00:40:41,805
you'd have a lot of big holes,
like in Swiss cheese.
700
00:40:46,711 --> 00:40:49,979
Narrator: At present, we can't
measure the ionized pockets
701
00:40:49,981 --> 00:40:53,049
to determine if
it was stars or black holes
702
00:40:53,051 --> 00:40:55,117
that lit up the early universe.
703
00:40:55,119 --> 00:40:58,187
Perhaps it was both --
704
00:40:58,189 --> 00:41:02,058
black holes and stars
working together.
705
00:41:02,060 --> 00:41:07,730
��
706
00:41:07,732 --> 00:41:09,799
the more we investigate
black holes,
707
00:41:09,801 --> 00:41:11,801
the more we learn
about their role
708
00:41:11,803 --> 00:41:14,136
as architects of the universe.
709
00:41:14,138 --> 00:41:23,145
��
710
00:41:23,147 --> 00:41:25,748
I think scientists
of my generation are very lucky
711
00:41:25,750 --> 00:41:31,487
to be able to be at the
beginning of this revolution.
712
00:41:31,489 --> 00:41:34,623
Narrator: We used to portray
black holes as monsters.
713
00:41:34,625 --> 00:41:37,159
Now we know that, without them,
714
00:41:37,161 --> 00:41:40,162
the universe would be
a very different place.
715
00:41:40,164 --> 00:41:42,032
They made life possible.
716
00:41:42,034 --> 00:41:45,701
Without black holes,
we probably wouldn't exist.
717
00:41:45,703 --> 00:41:46,970
Narrator:
We're discovering
718
00:41:46,972 --> 00:41:50,239
just how black holes
shaped the universe,
719
00:41:50,241 --> 00:41:56,378
but the more we learn,
the more questions they pose.
720
00:41:56,380 --> 00:41:58,513
I've spent my career
studying black holes,
721
00:41:58,515 --> 00:42:01,917
and I want to spend the rest of
my career studying black holes,
722
00:42:01,919 --> 00:42:05,255
and I guarantee you that,
at the end of my career,
723
00:42:05,257 --> 00:42:07,857
on the day I retire,
I will probably have
724
00:42:07,859 --> 00:42:11,360
more questions about black holes
than I do today.
725
00:42:13,931 --> 00:42:15,664
This is an incredibly
exciting time
726
00:42:15,666 --> 00:42:17,266
for black-hole science.
727
00:42:17,268 --> 00:42:19,135
Who knows what
we're gonna discover?
728
00:42:19,137 --> 00:42:28,511
��
58574
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