TED2019
Sheperd Doeleman: Inside the black hole image that made history
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At the center of a galaxy more than 55 million light-years away, there's a supermassive black hole with the mass of several billion suns. And now, for the first time ever, we can see it. Astrophysicist Sheperd Doeleman, head of the Event Horizon Telescope collaboration, speaks with TED's Chris Anderson about the iconic, first-ever image of a black hole -- and the epic, worldwide effort involved in capturing it.
Sheperd Doeleman - Astrophysicist
Sheperd Doeleman led the global team behind the Event Horizon Telescope that captured the historic, first-ever image of a black hole. Full bio
Sheperd Doeleman led the global team behind the Event Horizon Telescope that captured the historic, first-ever image of a black hole. Full bio
Double-click the English transcript below to play the video.
00:13
Chris Anderson: Shep,
thank you so much for coming.
thank you so much for coming.
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I think your plane landed
literally two hours ago in Vancouver.
literally two hours ago in Vancouver.
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Such a treat to have you.
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So, talk us through how do you get
from Einstein's equation to a black hole?
from Einstein's equation to a black hole?
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Sheperd Doeleman: Over 100 years ago,
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Einstein came up with this
geometric theory of gravity
geometric theory of gravity
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which deforms space-time.
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So, matter deforms space-time,
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and then space-time tells matter in turn
how to move around it.
how to move around it.
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And you can get enough matter
into a small enough region
into a small enough region
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that it punctures space-time,
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and that even light can't escape,
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the force of gravity
keeps even light inside.
keeps even light inside.
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CA: And so, before that,
the reason the Earth moves around the Sun
the reason the Earth moves around the Sun
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is not because the Sun
is pulling the Earth as we think,
is pulling the Earth as we think,
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but it's literally changed
the shape of space
the shape of space
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so that we just
sort of fall around the Sun.
sort of fall around the Sun.
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SD: Exactly, the geometry of space-time
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tells the Earth
how to move around the Sun.
how to move around the Sun.
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You're almost seeing a black hole
puncture through space-time,
puncture through space-time,
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and when it goes so deeply in,
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then there's a point at which
light orbits the black hole.
light orbits the black hole.
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CA: And so that's, I guess,
is what's happening here.
is what's happening here.
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This is not an image,
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this is a computer simulation
of what we always thought,
of what we always thought,
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like, the event horizon
around the black hole.
around the black hole.
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SD: Until last week, we had no idea
what a black hole really looked like.
what a black hole really looked like.
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The best we could do were simulations
like this in supercomputers,
like this in supercomputers,
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but even here you see this ring of light,
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which is the orbit of photons.
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That's where photons
literally move around the black hole,
literally move around the black hole,
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and around that is this hot gas
that's drawn to the black hole,
that's drawn to the black hole,
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and it's hot because of friction.
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All this gas is trying to get
into a very small volume, so it heats up.
into a very small volume, so it heats up.
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CA: A few years ago,
you embarked on this mission
you embarked on this mission
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to try and actually image
one of these things.
one of these things.
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And I guess you took --
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you focused on this galaxy way out there.
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Tell us about this galaxy.
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SD: This is the galaxy --
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we're going to zoom into the galaxy M87,
it's 55 million light-years away.
it's 55 million light-years away.
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CA: Fifty-five million.
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SD: Which is a long way.
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And at its heart,
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there's a six-and-a-half-billion-
solar-mass black hole.
solar-mass black hole.
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That's hard for us
to really fathom, right?
to really fathom, right?
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Six and a half billion suns
compressed into a single point.
compressed into a single point.
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And it's governing some of the energetics
of the center of this galaxy.
of the center of this galaxy.
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CA: But even though that thing is so huge,
because it's so far away,
because it's so far away,
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to actually dream
of getting an image of it,
of getting an image of it,
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that's incredibly hard.
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The resolution would be incredible
that you need.
that you need.
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SD: Black holes are the smallest
objects in the known universe.
objects in the known universe.
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But they have these outsize effects
on whole galaxies.
on whole galaxies.
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But to see one,
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you would need to build a telescope
as large as the Earth,
as large as the Earth,
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because the black hole
that we're looking at
that we're looking at
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gives off copious radio waves.
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It's emitting all the time.
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CA: And that's exactly what you did.
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SD: Exactly. What you're seeing here
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is we used telescopes
all around the world,
all around the world,
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we synchronized them perfectly
with atomic clocks,
with atomic clocks,
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so they received the light waves
from this black hole,
from this black hole,
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and then we stitched all of that data
together to make an image.
together to make an image.
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CA: To do that
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the weather had to be right
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in all of those locations
at the same time,
at the same time,
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so you could actually get a clear view.
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SD: We had to get lucky
in a lot of different ways.
in a lot of different ways.
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And sometimes, it's better
to be lucky than good.
to be lucky than good.
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In this case, we were both,
I like to think.
I like to think.
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But light had to come from the black hole.
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It had to come
through intergalactic space,
through intergalactic space,
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through the Earth's atmosphere,
where water vapor can absorb it,
where water vapor can absorb it,
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and everything worked out perfectly,
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the size of the Earth
at that wavelength of light,
at that wavelength of light,
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one millimeter wavelength,
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was just right to resolve that black hole,
55 million light-years away.
55 million light-years away.
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The universe was telling us what to do.
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CA: So you started capturing
huge amounts of data.
huge amounts of data.
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I think this is like half the data
from just one telescope.
from just one telescope.
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SD: Yeah, this is one of the members
of our team, Lindy Blackburn,
of our team, Lindy Blackburn,
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and he's sitting with half the data
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recorded at the Large
Millimeter Telescope,
Millimeter Telescope,
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which is atop a 15,000-foot
mountain in Mexico.
mountain in Mexico.
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And what he's holding there
is about half a petabyte.
is about half a petabyte.
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Which, to put it in terms
that we might understand,
that we might understand,
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it's about 5,000 people's
lifetime selfie budget.
lifetime selfie budget.
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(Laughter)
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CA: It's a lot of data.
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So this was all shipped,
you couldn't send this over the internet.
you couldn't send this over the internet.
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All this data was shipped to one place
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and the massive computer effort began
to try and analyze it.
to try and analyze it.
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And you didn't really know
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what you were going to see
coming out of this.
coming out of this.
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SD: The way this technique
works that we used --
works that we used --
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imagine taking an optical mirror
and smashing it
and smashing it
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and putting all the shards
in different places.
in different places.
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The way a normal mirror works
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is the light rays bounce
off the surface, which is perfect,
off the surface, which is perfect,
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and they focus in a certain point
at the same time.
at the same time.
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We take all these recordings,
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and with atomic clock precision
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we align them perfectly,
later in a supercomputer.
later in a supercomputer.
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And we recreate
kind of an Earth-sized lens.
kind of an Earth-sized lens.
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And the only way to do that
is to bring the data back by plane.
is to bring the data back by plane.
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You can't beat the bandwidth
of a 747 filled with hard discs.
of a 747 filled with hard discs.
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(Laughter)
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CA: And so, I guess a few weeks
or a few months ago,
or a few months ago,
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on a computer screen somewhere,
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this started to come into view.
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This moment.
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SD: Well, it took a long time.
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CA: I mean, look at this.
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That was it.
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That was the first image.
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05:12
(Applause)
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So tell us what
we're really looking at there.
we're really looking at there.
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SD: I still love it.
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(Laughter)
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So what you're seeing
is that last orbit of photons.
is that last orbit of photons.
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You're seeing Einstein's
geometry laid bare.
geometry laid bare.
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The puncture in space-time is so deep
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that light moves around in orbit,
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so that light behind the black hole,
as I think we'll see soon,
as I think we'll see soon,
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moves around and comes to us
on these parallel lines
on these parallel lines
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at exactly that orbit.
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It turns out, that orbit is
the square root of 27
the square root of 27
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times just a handful
of fundamental constants.
of fundamental constants.
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It's extraordinary
when you think about it.
when you think about it.
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CA: When ...
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In my head, initially,
when I thought of black holes,
when I thought of black holes,
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I'm thinking that is the event horizon,
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there's lots of matter and light
whirling around in that shape.
whirling around in that shape.
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But it's actually
more complicated than that.
more complicated than that.
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Well, talk us through this animation,
because it's light being lensed around it.
because it's light being lensed around it.
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SD: You'll see here that some light
from behind it gets lensed,
from behind it gets lensed,
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and some light does a loop-the-loop
around the entire orbit of the black hole.
around the entire orbit of the black hole.
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But when you get enough light
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from all this hot gas
swirling around the black hole,
swirling around the black hole,
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then you wind up seeing
all of these light rays
all of these light rays
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come together on this screen,
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which is a stand-in
for where you and I are.
for where you and I are.
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And you see the definition of this ring
begin to come into shape.
begin to come into shape.
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And that's what Einstein predicted
over 100 years ago.
over 100 years ago.
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CA: Yeah, that is amazing.
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So tell us more about
what we're actually looking at here.
what we're actually looking at here.
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First of all, why is part of it
brighter than the rest?
brighter than the rest?
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SD: So what's happening
is that the black hole is spinning.
is that the black hole is spinning.
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And you wind up with some of the gas
moving towards us below
moving towards us below
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and receding from us on the top.
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And just as the train whistle
has a higher pitch
has a higher pitch
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when it's coming towards you,
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there's more energy from the gas
coming towards us than going away from us.
coming towards us than going away from us.
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You see the bottom part brighter
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because the light is actually
being boosted in our direction.
being boosted in our direction.
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CA: And how physically big is that?
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SD: Our entire solar system
would fit well within that dark region.
would fit well within that dark region.
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And if I may,
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that dark region is the signature
of the event horizon.
of the event horizon.
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The reason we don't see light from there,
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is that the light that would come
to us from that place
to us from that place
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was swallowed by the event horizon.
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So that -- that's it.
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CA: And so when we think of a black hole,
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you think of these huge rays
jetting out of it,
jetting out of it,
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which are pointed
directly in our direction.
directly in our direction.
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Why don't we see them?
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SD: This is a very powerful black hole.
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Not by universal standards,
it's still powerful,
it's still powerful,
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and from the north and south poles
of this black hole
of this black hole
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we think that jets are coming.
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Now, we're too close
to really see all the jet structure,
to really see all the jet structure,
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but it's the base of those jets
that are illuminating the space-time.
that are illuminating the space-time.
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And that's what's being bent
around the black hole.
around the black hole.
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CA: And if you were in a spaceship
whirling around that thing somehow,
whirling around that thing somehow,
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how long would it take
to actually go around it?
to actually go around it?
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SD: First, I would give anything
to be in that spaceship.
to be in that spaceship.
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(Laughter)
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Sign me up.
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There’s something called the --
if I can get wonky for one moment --
if I can get wonky for one moment --
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the innermost stable circular orbit,
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that's the innermost orbit at which
matter can move around a black hole
matter can move around a black hole
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before it spirals in.
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And for this black hole, it's going to be
between three days and about a month.
between three days and about a month.
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CA: It's so powerful,
it's weirdly slow at one level.
it's weirdly slow at one level.
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I mean, you wouldn't even notice
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falling into that event horizon
if you were there.
if you were there.
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SD: So you may have heard
of "spaghettification,"
of "spaghettification,"
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where you fall into a black hole
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and the gravitational field on your feet
is much stronger than on your head,
is much stronger than on your head,
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so you're ripped apart.
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This black hole is so big
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that you're not going to become
a spaghetti noodle.
a spaghetti noodle.
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You're just going to drift
right through that event horizon.
right through that event horizon.
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CA: So, it's like a giant tornado.
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When Dorothy was whipped by a tornado,
she ended up in Oz.
she ended up in Oz.
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Where do you end up
if you fall into a black hole?
if you fall into a black hole?
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(Laughter)
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SD: Vancouver.
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(Laughter)
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CA: Oh, my God.
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(Applause)
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It's the red circle, that's terrifying.
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No, really.
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SD: Black holes really are
the central mystery of our age,
the central mystery of our age,
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because that's where the quantum world
and the gravitational world come together.
and the gravitational world come together.
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What's inside is a singularity.
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And that's where
all the forces become unified,
all the forces become unified,
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because gravity finally is strong enough
to compete with all the other forces.
to compete with all the other forces.
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But it's hidden from us,
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the universe has cloaked it
in the ultimate invisibility cloak.
in the ultimate invisibility cloak.
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So we don't know what happens in there.
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CA: So there's a smaller one of these
in our own galaxy.
in our own galaxy.
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Can we go back
to our own beautiful galaxy?
to our own beautiful galaxy?
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This is the Milky Way, this is home.
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And somewhere in the middle of that
there's another one,
there's another one,
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which you're trying to find as well.
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SD: We already know it's there,
and we've already taken data on it.
and we've already taken data on it.
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And we're working on those data right now.
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So we hope to have something
in the near future, I can't say when.
in the near future, I can't say when.
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CA: It's way closer
but also a lot smaller,
but also a lot smaller,
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maybe the similar kind of size
to what we saw?
to what we saw?
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SD: Right. So it turns out
that the black hole in M87,
that the black hole in M87,
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that we saw before,
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is six and a half billion solar masses.
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But it's so far away
that it appears a certain size.
that it appears a certain size.
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The black hole in the center of our galaxy
is a thousand times less massive,
is a thousand times less massive,
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but also a thousand times closer.
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So it looks the same
angular size on the sky.
angular size on the sky.
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CA: Finally, I guess,
a nod to a remarkable group of people.
a nod to a remarkable group of people.
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Who are these guys?
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SD: So these are only some of the team.
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We marveled at the resonance
that this image has had.
that this image has had.
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If you told me that it would be
above the fold in all of these newspapers,
above the fold in all of these newspapers,
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I'm not sure I would
have believed you, but it was.
have believed you, but it was.
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Because this is a great mystery,
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and it's inspiring for us,
and I hope it's inspiring to everyone.
and I hope it's inspiring to everyone.
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But the more important thing is that
this is just a small number of the team.
this is just a small number of the team.
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We're 200 people strong with 60 institutes
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and 20 countries and regions.
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If you want to build a global telescope
you need a global team.
you need a global team.
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And this technique that we use
of linking telescopes around the world
of linking telescopes around the world
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kind of effortlessly sidesteps
some of the issues that divide us.
some of the issues that divide us.
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And as scientists, we naturally
come together to do something like this.
come together to do something like this.
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CA: Wow, boy, that's inspiring
for our whole team this week.
for our whole team this week.
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Shep, thank you so much for what you did
and for coming here.
and for coming here.
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SD: Thank you.
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(Applause)
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ABOUT THE SPEAKER
Sheperd Doeleman - AstrophysicistSheperd Doeleman led the global team behind the Event Horizon Telescope that captured the historic, first-ever image of a black hole.
Why you should listen
Sheperd Doeleman is the project director of the Event Horizon Telescope and an astrophysicist with the Harvard-Smithsonian Center for Astrophysics. His research focuses on problems in astrophysics that require ultra-high resolving power. His work employs the technique of very-long-baseline interferometry (VLBI), synchronizing geographically distant radio dishes into an Earth-sized virtual telescope. In addition to his work at the Harvard-Smithsonian Center for Astrophysics and for the Event Horizon Telescope, Doeleman is a Harvard senior research fellow and a project coleader of Harvard's Black Hole Initiative.
Doeleman's research includes work at the McMurdo Station on the Ross Ice Shelf in Antarctica and as assistant director of the MIT Haystack Observatory. He is a Guggenheim Fellow and was the recipient of the DAAD German Academic Exchange grant for research at the Max-Planck-Institut für Radioastronomie. He leads and coleads research programs supported by grants from the National Science Foundation, the National Radio Astronomy Observatory ALMA-NA Development Fund, the Smithsonian Astrophysical Observatory, the MIT International Science & Technology Initiatives (MISTI), the Gordon and Betty Moore Foundation and the John Templeton Foundation. Doeleman received his BA from Reed College and completed a PhD in astrophysics at MIT.
Sheperd Doeleman | Speaker | TED.com