Original subtitles

Black holes.

The most formidable yet mysterious entities

in our Universe.

For over two years,

our cameras have followed a team of international scientists

trying to reveal their ultimate secret.

Attention, attention!

Call Station 42.

They are taking the first-ever picture

of a black hole.

If you ask why this hasn't been done before,

it's because it's really, really hard.

To pull off this extraordinary feat,

they must travel to the most hostile environments

in the world...

It's pretty cold.

The windchill right now is around minus 70.

...to build a network of telescopes

the size of planet earth.

Their goal: To reveal a picture of a black hole

that will challenge the theories of Albert Einstein

and could pave the way to a revolution in physics.

It will be one of the most thrilling discoveries

of our age.

This is the inside story

of the mission to capture the first real image

of a black hole.

In the expanse of our Universe,

there is one object so mysterious

it puzzles the greatest scientific minds.

The black hole.

Pretty much every crazy idea

that sounds like Sci-Fi

has been put forward in a serious physics journal

as something that can happen inside of black holes.

It's really the frontier of the wild west of physics.

A black hole is a region of space

where the pull of gravity is so powerful

that nothing at all can escape if it gets too close.

And by nothing, I really mean nothing,

including even light itself.

What we really mean by that

is this area called the event horizon.

It's a specific limit

around the black hole

that marks what's inside and what's outside.

Once anything crosses that boundary,

adios, it is out of contact with the rest of the Universe.

We don't know what its ultimate fate is,

but probably it ain't very good.

Most scientists today

believe that black holes really exist.

But nobody has ever actually seen one.

We have identified lots of objects

that look like black holes,

but you can't prove that they're black holes.

This is where the problem comes, right?

If nobody has ever seen a black hole,

can we be sure that they really exist?

Could this fundamental notion about our Universe

and how it works

be wrong?

Astronomer Shep Doeleman

from the Smithsonian Astrophysical Observatory

is on a mission to solve this mystery.

He's spearheading an extraordinary experiment.

Shep wants to take the first-ever photograph

of a black hole.

The goal of the entire project

is to see what a black hole really looks like,

detect its shape

and see what's happening immediately surrounding it,

because that's where the action is.

We are really in uncharted territory.

So it's all a bit of a gamble.

It's what we call high risk, high payoff.

Here at the Haystack Observatory

and across the world,

Shep has been developing a technique

to try and see the unseen.

Shep is targeting the very center of the galaxy,

where astronomers have recorded a cluster of stars

orbiting something strange.

The stars are orbiting so fast,

scientists have calculated

it must have the mass of over 4 million suns.

The best explanation?

A black hole.

Shep wants to use radio-telescopes

to try and see this black hole.

But there's a problem.

Although it's predicted to be much larger than the sun,

from earth it's 26,000 lightyears away.

This is such a small target,

there's no telescope in existence

that has the power to see it.

The entire reason this hasn't been done up till now

is that black holes are extremely small.

It would be the equivalent of trying to see an orange

at the distance of the moon.

So we have to build a telescope.

We have to build a fundamentally new instrument

that can see things that are that small.

To achieve this unprecedented power,

for the last decade,

Shep has been working towards a master-plan.

He wants to combine eight separate telescopes...

In Spain,

Mexico,

Arizona,

Hawaii,

Chile,

and the South Pole.

This earth-sized network

is called the Event Horizon Telescope.

To capture the crucial image,

all eight dishes must point towards the black hole

at exactly the same time.

We're linking telescopes about 10,000 kilometers apart,

even more than that.

By spanning the globe,

you create a new kind of instrument

that can see a black hole.

That's the secret sauce,

that's the secret of the Event Horizon Telescope.

It's a monumental technological undertaking.

At each of the eight observatories across the world,

radio waves from around the black hole

must be recorded

and the data stored

onto hundreds of specialized hard drives.

These drives must then be transported

to the Max Planck institute in Germany

and Haystack Observatory in Massachusetts,

where the data will be combined inside giant supercomputers

called correlators.

This correlator is the final piece of the puzzle.

The first part is collecting data

at different spots around the globe.

The second piece, though, is combining that data.

And that's what the correlator does.

Only then will this earth-sized telescope network

have a chance to make an image of a black hole.

If the Event Horizon Telescope

manages to actually take a high-quality photo

of a black hole,

that's not an impressive feat;

it's a mind-blowing feat.

It's a technical tour de force like we've never seen before.

But what does Shep's team hope to see

if a black hole allows nothing, not even light, to escape?

A black hole itself is invisible,

but matter falling into it

should give it away.

Its intense gravity attracts interstellar gas

and pulls it into a faster and faster orbit.

This heats the gas to billions of degrees

and emits a glow

that the telescopes may be able to detect.

If our ideas about black holes are true,

the team predicts they will see a circular ring of light

and the shadow of a black hole.

For physicists, a lot is at stake.

A picture of a black hole

will test one of the most treasured theories in science,

Einstein's theory of general relativity.

His theory says that mass curves the fabric of space and time,

creating an effect that we call gravity.

Einstein's theory of relativistic gravity,

that is what lays the foundations

that set all of our understanding.

Step 1 is just, did Einstein get it right?

Is there some detail that's been overlooked?

For a hundred years,

Einstein's theory has passed every test.

But nobody has ever seen its most extreme prediction.

If enough mass was crushed into a small enough space,

the gravity would be so strong,

it would form a black hole.

How wonderful would it be

if the Event Horizon Telescope shows us that in extreme realms,

Einstein is not completely right?

It will be one of the most thrilling discoveries of our age

as we will then leap-frog forward

in our grasp of how the Universe works.

A challenge to Einstein's theory

and a new era of astronomy

rests on the success

of the event horizon telescope team.

There are now just three months

until the team will attempt to observe the black hole

using a network of eight telescopes.

But there's a lot to do.

Shep has come to one of the telescopes in the network

to oversee a crucial test run.

What really gets us out of bed,

what really gets us motivated for this,

is building a new kind of instrument.

When you think of building a telescope

as large as the earth,

that in and of itself is such a crazy idea.

None of the telescopes were originally designed

to connect in this giant network.

So the team must fit each telescope

with special equipment

and customize them to make it work.

We're operating a little bit on faith...

Faith that we've checked everything that we can

and that it's working properly.

Shep and the team are hoping that the test run

goes according to plan.

We spend all of our time being paranoid.

There's a saying, only the paranoid survive.

To connect the telescopes together,

the team is using a special technique

called very-long-baseline interferometry.

But there is a big challenge.

During the observations,

they won't see any results in real time.

The very nature of the technique we're using

is that we're not gonna know if these observations work

until we get all the data back

to a central processing facility.

So we're here to do what's called a dry run,

to make sure that everything runs like clockwork.

Scan 2.

Somebody wrote .78. It's .078.

Who wrote that?

During the critical observation run,

there's a lot that can go wrong.

The radio signal from the black hole

must be recorded at each telescope

and the data stored onto specialized hard drives.

But clouds can obscure the signal

and equipment could fail,

knocking one or more

of the telescopes

out of the network.

So the team needs clear weather

and perfectly working telescopes

at every location across the globe,

simultaneously.

If just one telescope fails,

they might not get an image.

After the data have been recorded,

the filled hard drives will be shipped

to Massachusetts and Germany,

where the data must be combined,

and they will know if their ambitious plan has worked.

Everything's all set?

Yeah, I hope so.

In Mexico,

astronomer Gopal Narayanan is in charge.

The whole purpose

of the test observations we're doing

is to bring in a couple

of new facilities.

We're going to bring in APEX, which is in Chile,

Pico Veleta in Europe,

and the South Pole Telescope.

Out of all of the telescopes in the network,

the South Pole is critical to make an image of a black hole.

From Mexico, the South Pole is nearly 8,000 miles away.

The huge distance between these telescopes

will help the team get an image with much greater resolution.

Physicist Dan Marrone and his team

have traveled here to the ends of the earth

to get the telescope ready.

By including the South Pole Telescope,

we really truly make a telescope the size of the earth.

It more than doubles the resolution of the array

and gives us that last bit of detail that we need

to make a picture of a black hole.

It's January,

and the weather is a biting 33 degrees below zero.

So it's pretty cold.

The windchill right now is around minus 70.

Despite the cold,

the team still needs to prepare for the test observations.

They must install this custom-built mirror

to the telescope

with submillimeter accuracy.

Ok. I do believe the tertiary is installed.

We have to have this mirror positioned

so that the light from this giant 10-meter telescope

is focused precisely on our receiver.

Uh, so that took a little bit of doing,

but we think we have it right about now.

The mirror is in,

but until the observations are complete,

they won't know if it's worked.

Back in Mexico,

Gopal and the team get ready to start the trial observation run

with the four telescopes.

They will record the radio emission

from bright sources called quasars

to test the network.

Data specialist Lindy Blackburn

is in charge of recording the data.

One minute to go.

One minute to go. Is Lindy happy with this?

Here we go. We're on.

But as the test observations begin...

Ok, recording.

There's an unexpected problem.

No lights.

No lights?

A bug in the code

means the recording lights are not coming on.

It's trying to record.

It's trying to record? Ok.

Sending data to record...

Only the very last step in this whole fine process,

which is albeit a very important step,

which is to record the damn data

we've collected all through the chain.

That is not happening right now.

Without data,

the telescope is knocked out of the network.

Lindy is working furiously to find the fixes.

And I think we're hopeful.

So the I.F. Levels look fine.

Yeah.

Tell me it's working, Lindy.

No.

Same problem.

I changed the order

that I thought was the initial problem with the...

You're hoping that we'll get

this recording to start, Lindy?

I really don't know.

All ready?

10 seconds to go.

Lights.

Yay!

Good job, Lindy!

It's 2:46 A.M.

The team has recorded the quasar data.

But they won't find out if the test has worked

until the data have been analyzed.

Only then will the team know

if they stand a chance on the real observation run

when they attempt to record an image of a black hole.

An image of a black hole will provide a new way

to test Einstein's most extreme theoretical predictions.

Einstein's equations show us

that if you spend an hour or two at the edge of a black hole

and then come back to earth, for instance,

earth might have aged ten thousand

or a million or a billion years.

So when we are observing

the event horizon of a black hole,

we are observing what really can be characterized

as a time machine.

Yet despite Einstein's equations,

even he didn't think that black holes could exist.

He didn't believe there was a way they could ever form.

That's a sensible objection that Einstein had.

I mean, after all, it would be very, very, very hard to do,

to crush all the mass of something to a point.

Einstein naturally and reasonably assumed

that matter just wouldn't allow itself

to be compacted that much.

But evidence of a mechanism has been growing.

Scientists now believe a black hole

is the corpse of a giant star

that's gone supernova.

Deep inside the debris,

the surviving core collapses to an infinitely small point.

This is called the singularity.

Its intense gravity warps space and time so severely

that nothing can escape,

forming the black hole's event horizon.

It's possible that black holes

are ultimately a figment of the mathematical equations

that Einstein gave us.

But how better to begin to push this understanding

than to look and see what's actually out there?

And that's the promise of the Event Horizon Telescope.

The team hopes to test these theories

by taking a picture of a black hole.

They have two targets

in the centers of two different galaxies...

One called Sagittarius A-Star;

the other called M87.

There are only a couple of targets

in the Universe currently

where the event horizon telescope

could hope to resolve the silhouette of a black hole,

to see the edge of the event horizon.

M87 is one of them.

This image showing emissions from M87

is the closest astronomers have come to seeing a black hole,

but it's not close enough.

If we want to image the event horizon

we have to make an image

of what's inside this little box here,

at the very central core of this galaxy.

That's what we've been directing all of our efforts towards

for over a decade...

To find out what happens

in this place that has been off limits to us

since the beginning of astronomy.

If they succeed,

computer simulations show they should see this.

A ring of light circling the edge of the black hole.

If we could see this ring,

it would be the best evidence that we have

for the existence of black holes.

It's been three months

since the event horizon telescope team ran a test

using four out of eight telescopes in their network.

Since the test run, they have been processing the data.

And despite the recording problems in Mexico,

the results showed that four telescopes

combined successfully as one.

The full observation run is now just one day away,

and Shep is at the black hole initiative

in Cambridge, Massachusetts.

This will be mission control.

The team needs to link eight world-leading,

multi-million-dollar observatories simultaneously

to capture their image.

They have a 10-day window at the telescopes.

But clouds at any one of the locations

will obscure the signal from the black hole

and ruin the data.

So each day Shep needs to make a call...

If the night is go or no-go.

Whether or not you energize

the Event Horizon Telescope on a given night,

that's the biggest decision you can make.

If you make the right one, then you've got great data.

If you make a wrong decision,

you've expended huge amounts of resources.

Each night of observation

will cost thousands of dollars

and eat up their limited hard-drive space.

Shep needs five nights of data

to stand the best chance of making an image.

Judging the weather conditions across the world

will be critical.

Pico might go above in the next couple of days.

The Alma looks good.

If you make the wrong go/no-go decision,

you may have jeopardized

your ability to image a black hole.

And that's what consumes us when we're in that room.

The communication and weather reports are online.

Now Shep needs to make sure the telescopes are ready.

We want to make sure that we understand where things stand

by the end of today, right?

Because if something is not technically ready,

then we really do have a problem.

High in the atacama desert of Chile...

Astronomer Alan Roy is at the APEX Telescope

to make final preparations.

Alan is responsible for the most critical part of the project...

The timing.

Timing is absolutely important to this project,

absolutely central.

It's the heart piece of the whole experiment.

You're putting in a lot of effort,

a lot of money, a lot of time,

and it's all hinging on getting that timing right.

The event horizon telescope network is so large,

the signal from the black hole

will arrive at each telescope

at a different point in time.

What's more, the earth rotates.

As it spins, the position of the telescopes in space

constantly changes.

If the team can't record the time the signals arrive

to within a millionth of a millionth of a second,

the telescopes will fail to combine as one.

To sync the telescopes together,

the team has spent $2 million

on some of the most accurate atomic clocks

in the world,

called hydrogen masers.

This is the hydrogen maser.

This clock keeps time to about a second in 10 million years.

Of course we don't wait 10 million years to measure it.

Alan must keep this clock at a stable temperature

so it runs precisely.

But there's a problem.

The chamber used to cool it is broken.

The bearings have seized, and we've got no cooling.

So that means the chamber overheats,

and the maser is then not very happy.

A faulty maser could be catastrophic.

In the remote atacama desert,

it's too far to call for an engineer.

But Alan has a resourceful solution.

The solution is to crack open the door of the chamber

so that the excess heat from the maser

can come out through the door.

It makes me a little nervous,

but the clock we have to take on faith, yes,

that it's running as it should.

This piece of tape

should keep the maser running correctly,

if it doesn't, the whole experiment could be at risk.

My hat is off to the folks

that can actually undertake

these experiments and observations

and make it work.

It's real, it's tangible,

and it's extreme and abstract at the same time.

In Hawaii, on the volcano mauna kea,

project manager Remo Tilanus hears from mission control.

So, just got the news.

It's a go.

So, ready to go and start observing.

This is the crucial moment

that over 10 years of hard work has been leading up to.

It's taken a long time to get to this point

that we're going to get a real shot

to get an image of a black hole.

And now finally the day is here.

Remo must ascend to over 13,000 feet,

to the top of the volcano.

Here two observatories,

the James Clerk Maxwell Telescope

and the submillimeter array,

are part of the network.

And Remo is up against the clock to get them ready.

Right.

We have to start tuning the receiver.

This mirror directs the radiation

into the receiver that we're going to use.

It's like tuning a radio.

It's going.

Looking good.

At the submillimeter array,

engineer Jonathan weintroub is checking the data recorders.

We have 50 minutes now

to run the checks before we start recording.

And high altitude doesn't help your brain function.

You tend to make more mistakes at altitude.

But across the mountain,

Remo hits a glitch.

Oh!

What the heck?

He fell out of lock.

The receiver won't lock on to the frequency.

Without a lock, the data from the telescope will be ruined.

Maybe our yig is unlocked.

Remo has no option

but to manually adjust the receiver settings.

Yeah, we stayed in lock.

Excellent.

The team is ready just in time.

I think we're all set.

Good.

Great. It has a nice signal.

Attention, attention.

Doors and roof will be opening, doors and roof will be opening.

Call Station 42, call Station 42.

Oh, JCT is open.

Remo directs the antenna onto the target...

And Jonathan gets ready to record the data.

5, 4, 3, 2, 1.

Are we going?

The event horizon telescope is on the way.

After years of work,

the teams at eight observatories across the world

are finally recording the radio emissions

from around a black hole.

Over the first two days of the run,

they successfully record two full nights of data.

But it's not easy.

We're tired.

You know, you wind up

just being up at all hours of the night.

Where is it? Where is...

Oh, so, it's in front.

We had a problem at one of the telescopes,

one of the bits of electronics that we rely on

was giving us some crazy results.

We're at the maser right now.

Look at channel number 17.

And ultimately we fixed it,

because we were in the room, we're working.

So far,

the weather has been perfect across the globe.

But on day three,

at the large millimeter telescope in Mexico,

the outlook is beginning to change.

That's a scary, scary webcam.

The LMT is just completely chaotic right now.

I mean, you saw the webcam.

They're socked in by fog, there's clouds rolling in.

It looks very, very dicey up there.

Yes, it's clearly building up.

A storm system looks like it's moving towards Mexico.

The telescope in Mexico, the LMT,

and the telescope in Arizona have dicey weather.

So we're just gonna wait.

Shep delays the go/no-go decision.

It's too close to call.

You guys have to explain these LMT webcams to me.

From one direction, it just looks like a vacation paradise.

And then from these other views,

it just looks like

you're heading into a vortex maelstrom of hell.

And I don't understand how three different views

can be so different.

Shep has to decide.

But now there's news from the Alma Observatory in Chile.

Hold on, hold on,

I want to make sure I understand what you just said.

You think there's a chance that the data from last night

from Alma are corrupted?

Um, there's a chance.

Corrupt data

could put the whole $50 million experiment

in jeopardy.

At eight telescopes across the world,

the team has been recording the emission from a black hole.

- Ok, recording. - Recording.

- Alright. - Oh, yes, yes.

They are three days

into their 10-day observation window,

but at the Alma Observatory in Chile,

the team thinks their entire second night of data

could be corrupt.

This is a whole new wrinkle for us.

If you had extra time, could you run this problem down?

Running it down is probably not likely.

It's a massive blow.

The team might now only have one night's worth of data

out of five they need.

With the weather outlook set to get worse,

Shep has to take a risk.

I think we should make this a go

because we're not gonna tear the system apart,

so we have to assume that Alma's going to be fine.

So I'm gonna say that we're gonna go.

Over the next five days,

the team avoids the storm

and observes for the remaining three nights.

We are recording the data.

Their hard drives fill up

with over 6 million gigabytes of precious data...

More storage than 12,000 laptop computers.

In Chile, Alan Roy and the team

finish what's been a tiring eight days.

This is coming up to the end of the last run.

We've got maybe three minutes.

I'm feeling weary but, but content.

The team has recorded their target

of five nights of data.

But only when all the data are combined together

will they know if they might see a black hole.

This is the interesting part. This is...

It's almost a game of bluff.

You've now spent more than a week here at the telescopes,

observed through the night,

and we still don't know if anything will come out of this.

Over in Cambridge, Shep is winding down.

This is the beginning of the end, right?

I mean, this is not the end by any stretch of the imagination.

We have a lot of work to do, a lot of work to do.

But we've taken this first big step.

At the South Pole,

after five months of total darkness,

flights resume once again.

Now the team can finally return the last remaining hard drives

back to the U.S. and Germany

and complete the processing from all eight telescopes.

At the black hole initiative,

Shep assembles team members from around the world

to test how to turn the new data into images.

The big challenge that we face

in this technique of the Event Horizon Telescope

is that we don't have

all the pixels in the image, if you will.

We have some of the pixels,

so the art is trying to figure out

what the entire image looks like

without having, you know,

everything that we'd like to have.

The team will test different computer algorithms

to see if they can create an accurate image.

But they won't attempt it on the target black holes just yet.

First we're putting on training wheels.

Right? We're taking baby steps.

And we're trying to use

the algorithms that we want to use

for Sag A-Star and M87,

but on well-known sources that are much brighter.

These bright sources

come from matter swirling into what's believed to be

a feasting black hole.

As the black hole accelerates the matter, it rips it apart

and launches jets of radiation into space.

These are quasars.

They can kick out more energy than a billion stars,

leaving a signature jet that's visible across the cosmos.

If we can get really good images on those sources,

then we know we'll be ready to go to the next phase.

Katie bouman is leading one of the teams

trying to make an image of a quasar.

It's really exciting,

the first time we're actually trying to make an image.

So, here is 3c120.

The quasar is too far away

to see the edge of the black hole,

but the team knows what the jet should look like

from existing telescopes.

But two days into this workshop,

the algorithms are not producing one consistent image.

I can make an image that looks like that,

and that's ridiculous.

We get a lot of different kind of structures

come out from the same data.

That's not a vote of confidence in those images, I guess.

Physicist Mareki Honma

is also not getting a clear image.

Here is a very bright spot.

So we believe there is something,

but the whole area, it just looks like noise.

If the team can't get the algorithms to work,

they won't be able to make an image of a black hole.

The Event Horizon Telescope team

has linked data from eight telescopes together

to try and capture an image of a black hole.

The team has had problems

creating a clear test image of a quasar,

but after a week of coding, the images start to improve.

And the jet has more detail

than anything the team has seen before.

I see this jet-like kind of structure shooting out.

It's incredible.

Look at all the structure.

The team has produced images now,

after going through this whole pipeline,

that seem very robust.

So that's the key.

You have to be so confident in your techniques

and your data handling,

that you trust them,

because for Sag A-Star, for M87,

we have no idea what we're gonna see.

After more than ten years of planning...

Yay!

$50 million,

and the combined brainpower

of over 200 international scientists...

Attention, attention.

Doors and roof will be opening.

Finally the time comes

to try and make an image of a black hole.

This has been a huge process,

a very, very careful process,

and the imaging team is now getting the first set of data

that they can use to make a photo of a black hole.

It's really exciting.

We just got the data,

and that's, you know, what we've been waiting for

for many years,

so it's a pretty exciting time for us.

This is the moment when we finally get to see

what a black hole might look like.

Each member of the team loads the data

and starts running their algorithms.

Are we gonna... Are we doing this?

Let's see it.

Ok, ready... set...

Go. Going, going, going...

The algorithms are producing

some tantalizing images.

This is very early stages,

this is exploratory surgery.

The patient is on the table,

we've opened the patient up,

we're looking inside,

we're trying to find out what we see.

Each member of the team

needs to zero in on one consistent image.

That is interesting.

Whoa.

Ha ha!

I'm getting something pretty similar, a little bit.

And with the data for the black hole M87,

one image soon becomes clear.

I see a circle-y feature. Ha!

A bright ring of light

circling the shadow of the black hole.

What I'm seeing on the screen here

is pretty startling.

This is a case where the signal is so clear

that it kind of hits you on the head with a hammer.

If this holds up,

it's going to be the discovery of my lifetime,

and I think of many other people's lifetime.

And... it's, uh,

it's really sobering to see what a black hole looks like

for the first time.

The image shows photons of light

being distorted into a ring by the power of gravity.

In the center,

a black hole with the mass of 6 billion suns

is swallowing the light that strays too close.

It is profound evidence

that confirms the existence of black holes

first predicted by Einstein's theory of gravity.

This shows us that space-time is distorted

in the way that Einstein felt it would be

at the black hole boundary,

at the most extreme environment in the Universe.

These photons are struggling to get away from this black hole.

And the black hole is tethering them

with its immense gravity.

And every once in a while,

some of them can just get away from the black hole

and come to us.

So we're seeing the very definition of this surface

where light is lost forever.

In 2019,

the Event Horizon Telescope team verified their data

and released their results to the world.

This is a groundbreaking scientific result.

For the Event Horizon Telescope team,

they hope it could transform the way we see the Universe.

When Galileo first proved

that you can take pictures of the sky with telescopes,

that didn't end astronomy;

it started it.

And in the same way,

the most important scientific legacy

of the Event Horizon Telescope

is gonna be the fact that it creates

an entirely new field of science.

If I know astronomers, when this thing is done,

they're gonna go, "ooh! What else can we do with this?"

I can certainly envision

that 10, 30, 50 years from now,

our description of black holes are gonna be

completely, radically different.

For Shep and the Event Horizon Telescope team,

they hope this is just the beginning.

We're not done.

We don't actually like things

to be tied up in a bow and finished.

This shows us how black holes eat and how they feed

in a way that has been impossible up to now.

This, most of all,

signals a whole new direction in astronomy.

And that's rare.

That is really extraordinary.