Original subtitles

The night sky glitters with enumerable stars,

but space has many objects

still hidden from our view

as if they were just waiting to be discovered.

Some four decades ago an astrophysicist

argued that at the heart of every galaxy

there exists a supermassive black hole.

A galaxy can have hundreds of billions of stars.

Many are concentrated in the galaxy's nucleus

making that part called the "bulge"

the brightest part.

And in the very center

an astounding phenomenon,

a supermassive black hole.

One as massive, in fact, as several billion suns,

a monster black hole.

Surrounding gases are sucked in

with powerful gravitational force

even light cannot escape.

Lynden-Bell's theory was that every galaxy

has this kind of supermassive

black hole at its center.

This is the Institute of Astromony

at the University of Cambridge.

Donald Lynden-Bell argued

for the existence of supermassive black holes

when he was 34 years old.

He is still unraveling their mysteries.

When he published his argument

that supermassive black holes exist in every galaxy

he was met with a storm of criticism.

I think most people felt that they knew

what galaxies were like,

and they didn't see any reason why

there should be enormous masses

in the middles of galaxies, so it was an idea,

but you know far out,

and not very much considered as natural.

However, subsequent observations

by space based telescopes,

and by giant telescopes on earth

have confirmed that supermassive black holes

do indeed exist.

Now it is conceded that supermassive black holes

have a deep connection not only

to the formation of galaxies,

but to the very structure of space itself.

This program is dedicated to understanding

these mysteries objects

that seem to dominate space.

Supermassive black holes.

The black hole is a bizarre space object

defined by the absence of everything

except gravitational force.

How do scientists wrap their minds around it?

It's complicated.

Seriously massive objects warp the fabric of space.

The heavier the star, that is the greater its mass,

the greater the distortion.

So light which would otherwise travel

in a straight path gets bent.

If a star of any given mass shrinks sufficiently

its density increases until

its local distortion of space is infinite.

That's a black hole.

A border develops separating the black hole

from the space around it.

Once this border has been crossed

going into the black hole even light cannot escape.

Border diameter is determined

by the weight of the compressed mass.

A hole with the same mass as earth

would be merely two centimeters across

something the mass of the sun six kilometers.

That's considered the size of the black hole.

Black holes are created the instant stars die.

Let's say a star

20 or more times larger than our sun

reaches the end of its life and explodes.

The stars own gravity than causes

its remaining core to implode infinitely

becoming a purely gravitational force.

When a black hole is born like this

from the death of a star

its diameter is 50 kilometers at most,

but one can find black holes

of truly monstrous proportions

over 10 billion kilometers in diameter.

Andrea Ghez is an expert

on this invisible phenomenon of the black hole.

It was when she saw the Apollo moon landing on TV

that her interest in space was awakened.

My biggest objective in life when I was very young

was to become a ballerina.

I see things spinning in space now

as opposed to myself.

The path was unclear,

and today I view doing astronomy,

and studying the black hole

as putting together one big puzzle.

Donald Lynden-Bell predicted

that a supermassive black hole

lurks at the heart of every galaxy.

Andrea Ghez tried to find such a black hole

in our own Milky Way Galaxy.

Actually, the first thing

that we're trying to do is watch how stars move.

That's the key to finding that there's a black hole.

The way you do this is by pointing your telescope

at the center of the galaxy,

and using a technique that allows you

to see the stars around the black hole.

Here's the black hole, and what you want to do

is you want to be able to see a star.

You want to be able to see a star

make a complete orbit around the center.

Ghez followed the movements of the stars for years

plotting their trajectories.

If they were, in fact, orbiting some unseen object

than that would be proof of a black hole.

The center of the Milky Way, however,

is 26,000 light years from earth.

Ascertaining the movements of stars around

a point so far off in space is no easy matter.

Mauna Kea, Hawaii,

home to several giant telescopes.

Ghez used one of the obervatories

on this summit, the Keck Observatory.

The Keck has two of the largest

telescopes in the world with primary mirrors

that are 10 meters in diameter.

Ghez's observations here began in 1995,

but Ghez and her team were not the only ones

searching for a supermassive black hole

in the center of our galaxy.

A European team based in the heart of Germany

had also been hunting the same monster.

The leader of these star trackers

is Stefan Gillessen.

I have a 10 meter telescope.

We have an eight meter telescope,

so our telescope is a bit smaller,

however, we are on the southern hemisphere

where the galactic center is visible for more hours

so we can observe from February to October.

The European team conducts its observations

at the Paranal Observatory in Chile.

The VLT array there comprises

four 8.2 meter telescopes.

But even with such advanced technology

success is elusive.

The problem is earth's atmosphere.

Atmospheric fluctuations blur the stars.

April 2002 the European team installs

epic making new equipment.

From the VLT at Paranal

they shoot laser beams into the night sky

to measure and adjust for

those atmospheric fluctuations.

Their special equipment succeeds

in doing just that.

The new method is called "adaptive optics."

It brings the stars into focus.

Corrected for atmospheric fluctuations

the stars shine much more clearly.

Ghez, who did not yet have adaptive optics

was at a disadvantage.

She minimized atmospheric fluctuations

by restricting exposure time in imaging the stars.

Meticulously, she charted their movements.

Success or failure depended on

choosing the right stars to follow.

At first both teams were following

a start designated SO-1.

But Ghez's attention was drawn to another star.

Another star which people were very

excited about in the earliest days was SO-1.

It was the star that was moving fastest, initially,

but it was SO-2

that as it got closer to the black hole

has become the fastest moving star

that we've known about.

This graphic represents Ghez's findings.

Knowing that stars orbit the center of the galaxy

was not enough to prove

the existence of a black hole.

In January of 2002 another star designated SO-2

was observed to be behaving strangely.

It was executing a blindingly fast and tight orbit

clocked at 5,000 kilometers per second

as if being swung violently around and around.

These were incredibly exciting times

because, of course, at every stage

of this experiment people said:

"You can't do it,"

or "What you're seeing isn't"

"what you should be seeing."

We initially saw that they were moving fast,

and people said:

"These stars aren't bound to the galaxy."

"You're not gonna see them curve."

Yet SO-2 was indeed curving in a rapid orbit.

This is an actual imaging sequence.

Exhaustive analysis showed it to be

a giant star with a mass equivalent to 10 suns.

The only thing that can make stars

move that fast is a lot of mass.

These stars are moving

because there's a lot of gravity,

and the only thing that makes that much gravity

in that small a space is a supermassive black hole.

With their adaptive optics

the strange behavior of SO-2

had not escaped the notice

of the European team either.

They succeeded in imaging SO-2

at around the same time.

Of course, that was the moment

everybody was extremely excited about

"Wow! that orbit is proving"

"there must be a mass,"

"and we can measure the mass."

We can actually calculate the mass.

It's an easy calculation.

Any student can do it,

and the result is extremely fascinating.

This mass which we are seeing in these images

is four million times the mass of the sun.

Finally, after 10 years of observations

it was determined that a supermassive black hole

does, in fact, exist in the center of our galaxy.

And it is bigger than was imagined

by many orders of magnitude.

Black holes created when stars die

are typically 50 kilometers in diameter at most,

but the one at the center of our galaxy is gigantic.

The diameter is estimated

to be 24 million kilometers.

That's like 17 of our suns lined up in a row.

Around this monster black hole rushes SO-2,

a giant blue star at 5,000 kilometers per second,

about 200 times the speed

at which the earth orbits the sun.

That is a speed made possible only by

the immense gravitational pull of a black hole.

In the center of our own galaxy,

but far from earth unfolds a dance of the stars.

It was this dancing of the stars

that proved the existence

of a supermassive black hole.

It was an idea, but you know, far out,

and not very much considered this natural.

It remained that way for about 15 years.

Lynden-Bell had predicted that

a supermassive black hole exists

at the center of every galaxy.

Apart from observing the orbits of the stars

there's another way to prove

the existence of such a black hole.

That's to observe the moment when

a black hole swallows up stars or gases.

As gases are sucked into a black hole

they first flatten into a disk.

Friction causes them to super heat,

and to emit intense radio waves.

If these radio waves can be detected

that can indicate the presence of a black hole.

The largest telescope in the world

for detecting extremely high frequency

millimeter band radio waves

is the 45 meter radio telescope

at the National Astronomical Observatory of Japan.

It was, in fact, a Japanese scientist

who first proved Lynden-Bell's theory that

a supermassive black hole

lies hidden in every galaxy.

It happened in 1990,

21 years after Lynden-Bell's prediction.

Naomasa Nakai was working at

the Nobeyama Radio Observatory

studying gases at the centers of galaxies.

He was interested in a galaxy

adjacent to the Big Dipper.

Galaxy M106, a spiral galaxy

21 million light years from earth.

Radio waves had been reported

to be issuing regularly from the nucleus of M106.

In addition to a 45 meter

diameter parabolic dish antenna

Nobeyama Radio Observatory

has some world class instrumentation.

Eight spectrometers capable

of minute observation of radio waves.

A single spectrometer is sufficient to observe

radio waves from the nucleus of a galaxy.

But to be thorough Nakai used two spectrometers

for the very center of the galaxy,

and flanked them with the six remaining ones.

That decision to use all eight instruments

led to the discovery of the century.

Nakai had simply wanted to put

all his spectrometers to some use,

but the results astonished him.

There were surprising spikes

on both ends of the combined graphs.

Nakai was especially struck

by the ones on the left.

This indicated something moving

at high velocities never before observed.

More detailed observations

were made using a high resolution telescope.

They found something remarkable

at the core of the galaxy.

A spinning disk.

This was a structure very like

the disk formed by gases

being sucked into a black hole.

The spikes recorded by

the eight Nobeyama spectrometers

were from this disk.

The disk was spinning furiously.

3.6 million kilometers an hour.

Detailed analysis revealed that

the mass at its center

was equivalent to 39 million of our suns.

It was, indeed, a monster black hole.

When his discovery was published

in 1995 Nakai received a letter.

The letter read:

"I have been waiting 26 years for such proof,"

"and congratulate you"

"on your great discovery."

The letter came from England.

The sender, none other than Donald Lynden-Bell,

who had predicted the existence

of supermassive black holes.

I was very happy because I didn't feel that

I absolutely knew.

I thought it was likely,

and gradually I thought it was

more and more likely.

A black hole equivalent to 39 million solar masses

was sucking in huge volumes of gas

with its tremendous gravitational force.

The dark object in the center

of this artist's conception is a black hole.

Its diameter is awesome

as if 160 of our suns were lined up in a row.

It is now thought that almost

all galaxies have these supermassive

black holes at their center.

The most advanced observational instruments

are detecting ever larger black holes.

Situated outside earth's atmosphere

the Hubble Space Telescope

can see space objects with great clarity.

Hubble took aim at NGC 7052,

a galaxy located 37 million light years away.

The image it captured was that of a huge disk

comprised of gases and stars.

In its center there ought to be

a supermassive black hole.

When we got this image

I was just super excited, I mean,

because it was such beautiful rich detail

that I really knew right when I saw this

that we were gonna be able

to get excellent spectra,

and really be able to determine

whether this galaxy has a black hole,

and how massive it is, so I was very, very excited.

The galaxy was, indeed,

harboring a supermassive black hole.

A black hole equivalent to

300 million solar masses.

That's more than 70 times larger

than the one at the center

of our own Milky Way Galaxy.

A black hole with a diameter of

1,200 of our suns lined up in a row.

Hubble has spotted an even larger one.

An ultra massive black hole.

This one is in M87, 59 million light years away.

Scientists had long been puzzled by

a band of white light there.

When Hubble was trained on

the galaxy's core the band of white light

was revealed to be a gigantic jet of gases.

As the gases are sucked violently

into the black hole a portion of them are rejected

in the form of this jet.

The mass of the black hole

at the base of this jet has been calculated

to be 6.4 billion solar masses.

That's 10 million times greater than

the supermassive black hole

at the center of our Milky Way Galaxy.

In size its diameter is equal to

25,000 of our suns lined up in a row.

Then, in 2011 the largest black hole

in history was discovered.

In the galactic nucleus of NGC 4889

there's an unimaginably monstrous

black hole with a mass equivalent

to 9.7 billion times that of our sun.

What scientists are most eager

to elucidate now is the process by which

these black holes become so large

they may start with the death of a star,

but how do they then grow to

billions of times their original size?

Trinity College at the University of Cambridge.

Isaac Newton, who formulated

the universal law of gravitation

conducted research here.

Martin Rees has served as

master of Trinity College.

Rees has conducted research

on supermassive black holes

together with Lynden-Bell.

The impetus for his research was

the discovery of galaxies

whose high energy cores were emitting

powerful radio waves.

Well, there were various alternative theories

about what might be happening

in the centers of the galaxies

which are putting out a concentrated

high source of power.

These ideas included a very dense cluster of stars.

A very massive star,

a binary, supermassive object, et cetera.

I realized that if you followed forward

the likely evolution of any of these objects

they would all have no alternative

to becoming a big black hole.

So any object emitting

sufficiently high amounts of energy

will inevitably become a supermassive black hole.

How then are supermassive black holes born?

The "Rees Diagram" as it was called

chartered the possible routes.

In the 30 years since

the Rees Diagram was published

there has been a succession of disoveries

of supermassive black holes.

At the same time the study of their birth

has also been progressing.

One scenario suggested by Rees

was the consolidation of several

smaller black holes.

At the end of their lives stars explode

forming relatively small black holes.

Hundreds of millions of them may cluster together

merging into one supermassive black hole.

This is NASA's space-based

Chandra X-ray Observatory.

Chandra has been examining a region

where black hole consolidation

is thought to be taking place.

Galaxy NGC 6240 is located

400 million light years from earth.

Actually, two galaxies are colliding there.

As Chandra examines their galactic cores

two bluish white spots appear.

They are both massive black holes,

one at the center of each galaxy.

This blue region here is a blowup of the center,

and you can see there are two little sources there.

One brighter, and one a bit fainter,

but each of those when we look at the spectrum

shows a very characteristic sign

that this is just emission from

a supermassive black hole in each case

which has never been seen before

until we had the beautiful Chandra image,

and could separate the two.

Two black holes in close proximity to each other,

but they cannot soon merge.

Rather like the earth and the moon

in their perpetual dance

the two black holes orbit about each other

without colliding.

So what about Rees's concept of

black holes merging to form

a supermassive black hole?

Masayuki Uemura uses a super computer

to create simulations of black hole mergers.

Here, he simulates the behaviors

of 10 black holes of equivalent mass.

The first consolidation happens

far sooner than expected.

It takes only 50 million years.

The process repeats.

Within about 500 million years

five black holes have merged into one.

Let's look at our actual universe.

There are galactic collisions,

and mergers all over the place.

And when galaxies merge

the thinking is that their black holes merge too.

Wherever galaxies cluster

there's bound to be a cluster of black holes.

That means a process of consolidation

of black holes.

This conforms to actual observations

of our universe.

A second Rees Diagram scenario

has a seed black hole becoming supermassive

by swallowing up gases and stars.

In that scenario

the monster is born by gulping down

an unbelievable quantity of gases

equivalent to hundreds of millions of our sun.

The gases are sucked in with so much force

that the friction produces incredible heat.

That violent process emits intense light,

and X-radiation, and blows away surrounding gases.

The result is that there are

no more gases to feed on,

and the black hole seizes to grow,

but how is it that such a huge quantity of gases

could be sucked in in the first place?

Gases that are being sucked in

blowing away other gases.

Ken Ohsuga studies this contradiction.

He has found a particular mechanism

within black holes by which they can continue

to draw in vast amounts of gases.

He's prepared a simulation of one scenario

for how supermassive black holes may be created.

As a black hole sucks in gases

it generates magnetic field lines which

penetrate the surrounding gas disk like hoops.

Thus embedded they are then distorted

by the swirl of the disk.

As the disk swirls the magnetic field lines

are caught in a spiral vortex

twisted and coiled like a spring.

This is a plasma jet a portion of the disk's gases

charged with energy such as light

shoots out in opposite directions

perpendicular to the disk.

Any remaining gases are sucked into the black hole

which grows supermassive.

Hubble has captured this

actual image of an intense jet

erupting from the center of a galaxy.

The gas guzzling scenario

for supermassive black hole creation

as outlined in the Rees Diagram

thus seems persuasive.

Martin Rees developed several theories

of supermassive black hole formation.

One was by the continuing consumption of gases.

Another was by the consolidation

of smaller black holes,

but the Rees Diagram indicated

a third possibility as well.

Under this third scenario

just after the creation of the universe

large clouds of gas condensed into

supermassive black holes directly

without first becoming stars at all.

Recently, evidence for this third scenario

has also come to light.

By combining information from

the Chandra X-ray and Hubble Space telescopes

Priyamvada Natarajan hunts for

supermassive black holes created

at the inception of the universe.

These far off galaxies were photographed by Hubble.

Among those circled on the screen

are some that are 12 billion light years away.

They are small galaxies

born immediately after the universe itself.

Some 200 of them have been identified.

Here's one as perceived by Chandra.

And it already has a supermassive black hole in it.

Natarajan was surprised to discover

that almost all 200 of them

had supermassive black holes in them.

If so many supermassive black holes

were already present immediately after

the creation of the universe

then that lends powerful support

to the third scenario in the Rees Diagram.

So just as we think a gas cloud

that is collapsing could make

the first star reasonably easily

the conditions that you need for making

a black hole seed directly without forming a star

instead of forming a star

also exist in the early universe.

Efforts are also underway

to confirm the third Rees Diagram

scenario computationally.

I think that it is the first time

that there is a lot of showing

that it is possible to produce

a precursor of a big black hole

in the form of a supermassive cloud.

This is a giant gas cloud.

100 light years in diameter.

70,000 years after it formed into a gas cloud

its gasses were compressed into

a disk one light year across.

The gas disk was equivalent in mass

to 100,000 of our suns.

It then condensed further

compressed by its own weight

giving rise to a supermassive black hole.

So the third scenario in the Rees Diagram

going directly from gas cloud to black hole

is a real possibility.

Studies of the origins of these

supermassive black holes are ongoing.

The latest research reveals that

the supermassive black holes do not simply grow fat

consuming everything nearby.

Surprisingly, they exert a huge constructive

effect on the space around them.

What these remarkable monsters

call home is a galaxy's core.

More specifically it's inside

the concentration of stars called the "bulge."

The shape and size of the bulge

varies with each galaxy.

John Kormendy has investigated

the relationship between the mass of a bulge,

and of its supermassive black hole.

The first galaxy he observed was Andromeda.

The supermassive black hole here

is equivalent to 150 million solar masses.

The bulge is approximately

1,000 times greater in mass.

Next, he looked at the Sombrero Galaxy.

The black hole here is one billion solar masses.

The mass of the bulge is approximately

1,000 times that.

Plotted on a graph coordinating the masses

of the bulges with those of the black holes

the galaxies form a nearly straight line.

In most galaxies the black hole

to bulge ratio of masses is one to 1,000.

This strong relationship between

the mass of supermassive black holes,

and their galaxies bulges

surprised many scientists.

We know that when gas densities

get very big you get a burst of new stars

being formed, and so at the same time

when this burst of stars is making the bulge

the rest of the gas is being fed to the black hole,

and making the black hole bigger.

So you get lots of new stars,

and you get a higher mass black hole,

and the two correlate.

A galaxy comprises hundreds of billions of stars.

It turns out that at the galactic cores

the black holes and the bulges

have a deep interrelationship.

A giant bulge will correlate

with a giant black hole.

A small bulge with a small black hole.

This strange law of outerspace

may mean that galaxies and black holes

evolve together.

Andrea Ghez discovered the supermassive black hole

at the center of our own Milky Way Galaxy.

She also found evidence

that it performs an astonishing function

within the galaxies bulge.

We've had one surprise after another

in our study of the center of the galaxy.

What we see is that there are

very massive stars which tells us

that they're very young stars.

The last thing you expect near a black hole

is to find a very young star

because black holes are very

inhospitable to star formation.

They should just tear apart any cloud

that might eventually become a star,

so you really don't expect to see

young stars, baby stars near a black hole,

and yet all the stars that told us

there's a black hole are the ones

we predicted shouldn't be there,

so it's one mystery after another.

Near the supermassive black hole

at the center of the Milky Way

Ghez found many baby stars.

This suggests something astounding

that new stars may be emerging

from the gases that originally accumulate

around a black hole.

The effect black holes have

on surrounding space is not limited

to the birthing of stars.

A project spear-headed by NASA

called TANAMI is endeavoring to capture

distant galaxies.

TANAMI involves the participation of

radio telescopes in a dozen locations

in the southern hemisphere.

Chiefly, in Australia, but also in Chile,

South Africa, and the South Pole.

One of its targets is a galaxy located

14 million light years from earth Centaurus A.

This is the image they obtained.

A clear view of a plasma jet violently shooting out

from an invisible black hole.

The jet bursts out at 30% of the speed of light.

Analysis of this jet turned up

something quite unexpected.

The jet shooting out of the black hole

even escapes the galaxy itself.

Its plume expands for a distance

of a million light years.

So the black hole doesn't just guzzle down gases

it sends out the stuff that stars are made of

far beyond its own galaxy.

The role of the supermassive black holes

in the universe is still largely mysterious,

but scientists are learning more and more.

Cosmos looks the same from Britain to Japan.

Indeed, the night sky is the same to all of us,

and has been the same to all our ancestors

throughout human history.

It's the one common feature of all humanity.

They've all looked up at the night sky,

and wondered at it,

and interpreted it in their own way.

It's a wonderful story

when we found all these extraordinary

objects in the universe, and we can understand

these vast cosmic horizons in a way

that our ancestors could only have dreamed of,

so it's a wonderful story.

Supermassive black holes.

Monsters in the galactic cores.

They may gobble up everything around them,

but they also give birth to stars,

and send out energy rich materials

into the universe.

Some came into being at the same time

as their galaxies, and grew along with them.

What role have they played in the formation

of the universe itself?

This is a great mystery, but one whose solution

may be surprisingly close.