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00:00Somewhere, not far from Earth, a star enters its death throes, and explodes in a violent
00:10supernova, leaving in its wake the strangest phenomenon in the cosmos, a black hole.
00:20Our galaxy may be infested with millions of them, but now there's evidence of something
00:26even more ominous.
00:29Black holes of unfathomable size and power.
00:32That's a big galaxy, and right down at the center, you can't see it, a black hole that's
00:38got a mass that approaches a billion suns.
00:43Astronomers are now studying them in unprecedented detail, and finding they are bigger, stronger,
00:49and more destructive than anyone imagined.
00:53We'd like to think black holes are far, far away, but what if there's one on our cosmic
00:58doorstep?
01:01A team from Europe and another from the United States are in a high-tech race to be the first
01:07to see into the very heart of the galaxy.
01:11Now an extraordinary new experiment is giving astronomers a first-ever glimpse inside a
01:16black hole, to see what's in the lair of the monster of the Milky Way.
01:37A new era in astronomy has begun, high-tech instruments in space are now revealing a universe
01:43rocked by violent events.
01:53In the distant galaxies, astronomers have witnessed space and time shattered by eruptions
01:58so vast they boggle the mind.
02:01To put this on sort of an earth scale, it's equivalent to about a trillion, trillion,
02:08trillion atomic explosions.
02:14But what could produce such awesome power?
02:19Whatever it is, it lives at the center of our own Milky Way.
02:26Scientists now believe it is the largest and most powerful object in the universe, and
02:30yet it emits no light.
02:36This is called a black hole.
02:39First suggested by Albert Einstein's equations, a black hole is space and time twisted into
02:44a furious knot, but the great scientists believed it could never exist in nature.
02:55Albert never really liked the idea of black holes himself.
02:59He thought they were anathema, this was something that nature should avoid.
03:04It's the places where space and time became infinitely twisted up.
03:09He thought, no, nature shouldn't allow that.
03:14Black holes are certainly odd beasts in the universe.
03:18They were thought to be peculiar, so peculiar as to perhaps not even really exist in the
03:23real world, simply because your equations show that they can exist, doesn't require
03:27that the real universe has them.
03:32There is something strange and powerful lurking in the center of our galaxy, first became
03:36clear 75 years ago.
03:38Early radio telescopes recorded a hit, like the sound of steam.
03:49As a young astronomer, Eric Bechlin was determined to get to the bottom of this mysterious energy
03:54source.
03:55First, he had to find it.
03:57There was a radio source called Sagittarius A, a very strong radio source, but there was
04:03even debate whether that was really the center or not.
04:07Astronomers knew that the centers of other galaxies are tightly packed with stars, but
04:11when they tried to see into the center of our galaxy, those stars were obscured behind
04:16a thick veil of dust.
04:21There is so much dust between us and the galactic center, it is completely opaque.
04:27You do not see the stars in the galactic center.
04:31The most powerful telescopes cannot see it.
04:37Bechlin knew that some kinds of light, invisible to our eyes, can make it through the dust.
04:43Infrared, for example, travels in slightly longer wavelengths.
04:49Infrared radiation gets through the dust because its wavelengths are longer and the dust just
04:56kind of rides on the infrared wave.
05:01In the 1960s, Bechlin bought an infrared detector from a military contractor and attached it
05:07to the end of a telescope.
05:09It was in August of 1966, and it was a beautiful night.
05:14As we were looking with the infrared detector, we were seeing more and more stars, and the
05:21signal increased, and each star gives you more signal.
05:26And we were building up, as we were getting closer to the center, more and more stars.
05:30We were actually seeing through the dust for the first time, and then came to a peak, and
05:38then back down again.
05:39And I knew immediately that that was the center of our Milky Way, and that I was the first
05:47person to actually see the stars in the very core of our galaxy.
05:53Eric Bechlin had discovered the very heart of the Milky Way, the exact location of the
05:58mysterious energy source.
06:00But its staggering power meant that this was no ordinary star.
06:05Scientists believe the only one thing that could explain the mystery was the very idea
06:09that Einstein had rejected, an object that defies explanation.
06:22What's a black hole?
06:23It's this monstrous, mysterious thing.
06:26It's a point of infinite density.
06:29We don't know how to wrap our brains around that.
06:33It's a region where space and time have closed in on itself.
06:38A black hole is a region of space where the pull of gravity is so immense that not even
06:44light can escape it.
06:46You reach the point where light cannot even come out, and if light can't come out, you're
06:50not coming out.
06:51And if light plus you are not coming out, it's a black hole.
06:54There's no other phrase we can possibly use to describe it.
06:58Welcome to the strange world of extreme physics, where space and time literally cascade into
07:04the abyss.
07:06Space itself is falling inside the black hole.
07:09It's rather like a river falling over a waterfall, except it's space itself that's falling over
07:15a cliff.
07:18It's rather like a kayaker trying to make their way upstream on a river that's going
07:23too fast.
07:24They get dragged down to the center of the black hole.
07:30Gravity becomes a riptide.
07:33The closer you get, the stronger the current.
07:35Eventually, you reach the event horizon, the point of no return.
07:48Matter goes inside the surface of the black hole, shrinks down to the very center where
07:54it gets destroyed in a region of infinite warp space and time, and it's gone.
08:02The gravity at your feet, if they're close to the black hole, is a little bit stronger
08:05than the gravity at your head, and you feel that as something that is tearing you apart.
08:11The tidal forces, unrelentingly getting stronger as they exceed the molecular forces that bind
08:18your flesh, and so you end up moving through space-time like toothpaste through a tube.
08:30Ultimately, you will pull your atoms apart.
08:33You will be, as we say, spaghettified.
08:36As strange as they are, black holes are a product of the familiar universe of stars
08:41and gravity.
08:42They have their genesis in a type of enormous star called a red supergiant.
08:47It is ten times heavier than our sun, yet it will burn itself out in a fraction of the
08:52sun's lifetime.
09:00Deep inside, the crush of gravity sends temperatures roaring above a billion degrees.
09:08Helium and carbon fuse into heavier elements, oxygen, silicon, sulfur.
09:18Then the star implodes under its own immense gravity, sending a shockwave roaring out.
09:24That star digs itself deeper into space travel and now goes supernova in a violent explosion.
09:31What's left is a dense core of subatomic particles, a neutron star, only about 16 kilometers across.
09:42It's so dense that a teaspoon full of neutron star matter would weigh about a billion tons.
09:47Eventually, the gravitational pressure will be so large that the neutrons themselves will
09:51be crushed and there'll be nothing left to stop the collapse.
10:05A black hole is born.
10:07It's a million times the mass of the earth, but compressed so tightly, it literally exits
10:12the known universe.
10:18Now the effect of that mass is still in our universe.
10:23The mass is still here in that it's causing this fold in space that goes all the way down.
10:33It's become a hole.
10:35The best way to look at it is, if you stick your finger down in there, you ain't getting
10:40it back.
10:42We know exactly what effect a black hole is going to have on its environment, on the stars
10:47in its vicinity, on the gas that wanders a little too close.
10:53So will we ever see a black hole?
10:56No.
10:58But that's not what's important here.
10:59What's important here is we can see its paw print.
11:05In search of a black hole's paw print, Eric Becklin is on a lifelong quest to probe the
11:10center of our galaxy.
11:18The Milky Way is a giant spiraling disk of over a hundred billion stars.
11:25Our sun is about halfway out in the peaceful suburbs.
11:29Becklin is headed to the galaxy's most exciting and most violent zones.
11:36To make the final leg of the journey, he would need help.
11:42So he turned to a rising star in astronomy.
11:45Andrea Goetz believes that the key to finding a black hole at the center of our galaxy lies
11:50in tracking the stars that buzz around it.
11:52For about three decades or so, there has been this question of whether or not our galaxy
11:58harbors a supermassive black hole at its center.
12:01And the key to answering this most definitively is to watch stars at the center of the galaxy
12:07orbiting.
12:08Goetz's team set up at the newly built Keck Telescope on the summit of Hawaii's Mauna
12:14Kea volcano, the largest telescope ever built.
12:21Our view to the center of the galaxy is absolutely superb.
12:24Our ability to position stars at the center of the galaxy is like somebody in Los Angeles
12:30seeing somebody in New York be able to move their finger like this, okay, just two centimeters.
12:36That's the precision with which we can measure something that is 26,000 light years away
12:43from us.
12:44Madeline, we're ready to go.
12:47The conclusive experiment to be done that really demonstrated there was a black hole
12:53was to follow the orbits of individual stars very, very accurately and with the highest
12:59precision possible.
13:02But the stars in the center of the galaxy were not the only thing Goetz and Becklin
13:06had to keep track of.
13:08Another group working in the mountains of Chile was hot on the same trail, led by Reinhard
13:13Gensel from Germany.
13:14This guy here, it's a little too dense to be just a random collection.
13:19We suspect that in the galactic center, there may be hiding very massive black holes.
13:25To really be sure that there are black holes, we have to go in there as close as we can.
13:30We can make measurements really good enough now that we can say it must be a black hole.
13:35Both teams wanted to be the first to prove that our galaxy harbors a supermassive black
13:39hole, but Gensel and his team had a three-year head start.
13:46The amazing precision of Keck is the ace in the hole for Goetz and her team.
13:51Mark Morris is a veteran of the galactic center search.
13:57The German group had already started to make headway on the galactic center even while
14:00we were deciding to pursue this.
14:02So we knew that in a head-to-head competition, that as long as they were using the small
14:072.2 meter telescope that they were using compared to our 10 meter telescope, that we would blow
14:13them away.
14:15Great spec on the top of this inset.
14:18That's the star which really has given us the essential clue for the black hole.
14:24It was certainly high excitement, but on the other hand, we would have to compile like
14:28at least five years of data before we could see the stars move.
14:33But what kind of cosmic monster was pulling the stars along?
14:38This is our roadmap.
14:39And that's the center of our galaxy.
14:43There's a large cluster of stars that are orbiting the center of our galaxy.
14:48Basically the way this experiment works is you take an image, you see where all the stars
14:51are, and then you come back sometime later and you take another image and you look to
14:55see if they've moved.
14:57So the second time we took an image, we knew we were golden, that those stars had clearly
15:03moved.
15:07The first order of business was to see how large the object is, to weigh it by measuring
15:12its gravity.
15:14So we have the black hole here, and the more massive it is, the more polar it is.
15:20The more polar it is, as it gets closer to the black hole, the faster it goes.
15:24And we are measuring the speed of these stars.
15:27That's the key to getting the masses, measuring the speed of those stars.
15:32Andrea's more advanced telescope made the difference.
15:36The object weighed in at a staggering 3 million times that of our sun.
15:43But that didn't prove it's a black hole.
15:46It could still be a cluster of smaller objects.
15:51For the Germans, it was time to even the playing field.
15:55The VLT, Very Large Telescope, opened its doors on a mountain in Chile.
16:01Both the VLT and Keck were upgraded with revolutionary technology.
16:05For years, the teams relied on computers to pinpoint the location of stars through
16:09the turbulence of our atmosphere.
16:15Now they could cancel it out with a new system known as Adaptive Optics.
16:20It uses a powerful laser beam to read the turbulence.
16:28Telescope operators can use those readings to sharpen the image of distant stars and
16:32galaxies.
16:35So this little animation shows you the benefit of Adaptive Optics.
16:41So you see the stars without Adaptive Optics, you turn the Adaptive Optics on, and all of
16:45a sudden you see stars, and in particular you see stars near the center of the galaxies.
16:50We track all of them, but these are the ones that are the key to the problem.
16:57These new eyes were delivered just in time.
17:00With both teams watching, one of the stars made a dramatic hairpin turn around the center.
17:05In 2002, it made a huge jump to over here.
17:08So it went, whoop, all the way around.
17:11That star was initially going very slowly, and then moving around very quickly, and at
17:16that point coming very, very close to the central black hole.
17:19And it's moving on order 10 million miles per hour, so it's just speeding away.
17:26The star had come close enough for the teams to see that it had to be circling a single
17:31massive object.
17:33All other physical explanations of what was at the very center were gone.
17:39The only thing left was the black hole.
17:42To astronomers around the world, the evidence was impressive.
17:45I have to say, when I first saw Andrea's video, I was stunned when I saw that star come out
17:50of the left side of the frame and go zipping around and go shooting off into the other
17:55end of the frame, and it moved around a point in space, and nothing was there.
18:02That we could, with our instruments, together with our minds, effectively travel to the
18:08center of the galaxy, 26,000 light years away, and collect the evidence for such an incredible
18:15object was really an amazing achievement.
18:20The European and American teams had confirmed that a black hole was there without actually
18:25seeing it.
18:26From our quiet corner at the far edge of our galaxy's spiral, it's hard to imagine the
18:31violence at its center.
18:35The closer you draw toward the center, the denser it gets.
18:41Your destination, the galaxy's central hub, brimming with stars, known simply as the bulge.
18:52Venture into the bulge, and you enter a busy highway.
18:55It's jammed with star traffic, speeding in every direction, and it's always rush hour.
19:01There's a lot of gas.
19:06There's a lot of dust.
19:08This is absolutely the most crowded place in our galaxy.
19:12There will be stars all around us, an incredible density of stars.
19:15I mean, we couldn't exist there.
19:17There's lots of ultraviolet radiation, x-rays are floating around, gas clouds bash into
19:21each other, a lot of activity.
19:23It's a very hostile environment, really.
19:30The black hole is surrounded by a cloud of super hot gas that's falling in.
19:34The space around the black hole is so warped, it distorts the light that scatters across it.
19:44As bizarre as it seems, the gravity of a super massive black hole is so spread out that you
19:49might fall in and survive for a moment.
19:53During the final descent, you would then go into the event horizon, but you would actually
19:58not feel it, because you are a small body compared to the large massive black hole.
20:04Now, thanks to a computer simulation based on Einstein's own equations, we can visualize the scene.
20:11As you move toward the black hole's core, you hit an inner horizon, a log jam of trapped
20:16light and energy.
20:19At a certain moment, as we hit the inner horizon, there's this infinitely bright, blinding flash
20:26of light.
20:27That's all the stuff that's been waiting there, trying to get out, is just held there at the
20:31inner horizon.
20:35It would vaporize you.
20:38Almost certainly, if you fell into a real black hole, you would simply, unfortunately, die.
20:49But that's not the end of the journey.
20:51The computer storm can be turned off, and the strange predictions of Einstein's equations
20:56allow it to play out.
21:04A passageway opens up, a tunnel through space and time, known as a wormhole.
21:09We now leave through a strange door, known as a white hole.
21:16Here, the twisted logic of extreme gravity goes into reverse.
21:24Instead of being sucked in, you would be catapulted out to the far reaches of time and space.
21:30But to where?
21:32In science fiction, wormholes offer handy escape routes to other universes.
21:36In reality, the inside of a black hole is probably too chaotic and violent for a wormhole
21:42ever to form.
21:49The black hole at the center of the Milky Way is strange enough as it is.
21:54But is it the norm, or is our galaxy a freak of nature?
22:02To find out, astronomers have mounted a major international project to search galaxies throughout
22:07the universe for evidence of supermassive black holes.
22:12From Apache Point in New Mexico, astronomers are probing big galaxies out to a billion
22:17light-years from Earth.
22:19They take a series of steel plates and drill holes to exactly match the location of galaxies
22:24in the night sky.
22:28Then they plug fiber-optic sensors into those holes, and for the first time ever, they can
22:34use the plates to capture the light of hundreds of galaxies per night.
22:41The astronomers are looking for a distinctive light signature coming from a galaxy's core.
22:46It's a sign of hot gas swirling into a black hole.
22:56The goal of the project, called the Sloan Digital Sky Survey, is to map a quarter of
23:01the entire northern sky, to find out what kind of galaxies make up our universe and
23:06how they are arranged.
23:15Of the 125 billion galaxies that make up the visible universe, more than a million
23:21have so far been analyzed.
23:26Nearly all the large ones, circled in red, bear the signature of a supermassive black
23:31hole.
23:34The closer we look to the centers of galaxies, the more we find these black holes, and the
23:38inventory is rising high.
23:40So any idea for the formation of a galaxy will now have to include some explanation
23:47for how you get a black hole in its center.
23:51But how did every big galaxy in the universe end up with a giant black hole in the middle?
23:56To understand, go back to the very beginning, the Big Bang.
24:07Matter and energy rush outward as the universe expands.
24:11So you've got the Big Bang handing you your birth ingredients, your hydrogen, your helium,
24:16your traces of some other elements.
24:18So it's kind of like this soup.
24:21You put it together and stir it.
24:24It's gravity that stirs the soup.
24:26Over billions of years, it molds the universe into a spider's web of gas and galaxies.
24:36In this web, gravity draws together wisps of hot, primordial gas.
24:43Over tens of millions of years, the clouds of hydrogen gas coalesce, growing more and
24:48more dense.
24:54Some grow hot enough to ignite.
24:58The first stars are born, giants, hundreds of times bigger than our sun.
25:03They burn out quickly and explode in the flash of a supernova.
25:13Billions of years later, an orbiting satellite called SWIFT is in position to capture that
25:18flash of light.
25:22SWIFT is the eyes of an international group of astronomers.
25:31Within 30 seconds of detecting a flash, it sends out an alert via mobile phones, pages,
25:37and emails.
25:38Adam, Mike Ford calling.
25:39We have a GRB detection.
25:40Please meet at the observatory and call the GRB team.
25:48The astronomers scramble to their telescopes.
25:54Speed is vital.
25:56They have to catch the light beam if they are to probe the dark secrets behind these
26:00distant disasters.
26:09First they determine how far it has traveled, give it a name, and pinpoint its birth galaxy.
26:15Then we are going to need to move the dome.
26:20By analyzing the light, they have gleaned the distinctive signatures of black holes
26:25being born.
26:29The most distant are the earliest generation of primordial monsters.
26:35We could be forming the seed of the supermassive black holes that we see in galaxies today
26:40very early on when the very first objects form in the universe.
26:46We can now with our big telescopes look back in time and sure enough what we find is that
26:51at the same time when the galaxies form, also the black holes form.
26:54It may very well be that they needed each other.
27:00This computer simulation shows how our Milky Way galaxy was born.
27:08It grew over billions of years from a swarm of smaller galaxies smashing together, merging.
27:18In a cosmic dance of death, the infant galaxies swirl around and orbit one another.
27:24Gravity pulling them closer.
27:29If another galaxy comes too close, they will each feel each other's gravity.
27:36What started out as a stately ballet of stellar orbits moving around the center of their galaxy
27:41has now become this, this maelstrom.
27:44There's no other way to say it, galactic cannibalism.
27:50That's what they're doing.
27:52They're dining on their neighbors, eating entire galaxies.
27:54Well, for every galaxy you eat, if that galaxy has a black hole in its center, it's going
27:59to eat the black hole.
28:00And the black hole will work its way down to the center of the large galaxy, making
28:06the center of the galaxy bigger as well as the galaxy itself.
28:11As galaxies swallow each other, the black holes at their centers merge and grow.
28:18There was an epoch once, about one, two, three billion years after the Big Bang, when in
28:24fact galaxies were forming, or at least they were tremendously more active than now.
28:29And at the same time, black holes already existed, had formed, and were fed at tremendous
28:36rates, producing very powerful quasars.
28:40Quasars are bright beacons of light at the centers of distant galaxies, where feeding
28:45black holes shine brighter than anything else in the universe.
28:49The Hubble Space Telescope peered into a dormant quasar in a nearby galaxy called M87.
28:55It found a tiny central region where gas is heated to tens of millions of degrees and
29:00whipped by gravity to millions of kilometers per hour.
29:08What became obvious was that there was a tremendous amount of mass in a very small volume.
29:14But that mass was very unlikely to be stars, like those stars that we see in our galaxy.
29:24Astronomer Brian McNamara believes giant ravenous black holes can have a profound effect on
29:29the surrounding galaxy and beyond.
29:32How can we get an offset, 180, 180, same direction?
29:41We are setting at 360, 360.
29:46Guider is locked up.
29:47McNamara is studying a trail of devastation left in their wake.
29:51Isn't that amazing?
29:53All of these other galaxies are gravitationally bound to this galaxy cluster.
30:00So they're all buzzing around this giant galaxy like bees buzzing around a hive.
30:06These clusters are the product of galactic cannibalism on a cosmic scale.
30:14This computer simulation shows how a galaxy cluster evolves in a dense region of the universe
30:19tens of millions of light years across.
30:23Hundreds of galaxies form, then swarm toward a common center.
30:27A central galaxy swallows them up.
30:30As it grows, so does the black hole.
30:39McNamara is searching for the monster's paw print.
30:44So that's a giant galaxy sitting in the middle of a cluster of galaxies.
30:48So the idea is that that's a big galaxy and right down at the center you can't see it.
30:53We think there's probably a black hole that's got a mass that approaches a billion suns.
30:59It very recently in the last several tens of millions of years gobbled up a lot of matter
31:06and it caused a huge eruption.
31:10McNamara zeroes in on a distant galaxy cluster two and a half billion light years away.
31:15Called MSO-7, it's hidden in a vast cloud of hot gas.
31:21There's an atmosphere of gas that pervades the entire galaxy cluster and it's an atmosphere
31:26like our atmosphere except that it's far less dense and it's much, much hotter.
31:34McNamara noticed that two immense cavities in this cloud had been hollowed out.
31:38That cavity here and this cavity here, we could stuff 600 Milky Ways in there.
31:44It's just astonishing.
31:46The energy involved is huge.
31:49McNamara believes this eruption of energy is the most powerful since the Big Bang itself.
31:57He traces its source to the core of the giant central galaxy, a supermassive black hole.
32:06But how does a black hole, a creature famous for devouring everything within its grasp,
32:11spew energy across the universe?
32:14As matter falls in, what we know now is that it spirals around in a disk,
32:21okay, very much the way when water goes down the drain.
32:26And the speeds that matter can achieve around that black hole approach the speed of light.
32:31And when matter travels at that speed, it gets a tremendous amount of energy.
32:36Matter falling into a black hole is a lot of stuff trying to get into a very small place.
32:43So it's like trying to fill a dog dish with a fire hose.
32:47Most isn't going to get in.
32:49A high-speed whirlpool of matter coils around the black hole,
32:54creating a powerful magnetic field that hurls enormous volumes of gas outward.
32:59It produces a powerful jet of matter, hundreds of millions of times the power of the sun,
33:05that blasts right out of the galaxy.
33:10There's no question that the black holes at the centers of galaxies
33:13have a profound influence on their surrounding.
33:16They send out these huge jets moving at almost the speed of light.
33:21And those jets can send shockwaves into the surrounding medium,
33:25change their surroundings completely.
33:27They have a dramatic influence.
33:30These jets can literally sterilize the galaxy by halting the formation of new stars.
33:36Principal galaxies can grow to very, very large sizes.
33:40And what we see in the universe is that they don't.
33:43And we think that the supermassive black holes at the center may be the culprit.
33:46They may be responsible for preventing runaway growth of galaxies.
33:53In smaller galaxies, all this violence can have a creative impact.
33:58Black hole blast waves spread heavy elements generated in the core of the galaxy,
34:03setting the stage for the formation of new solar systems.
34:11We usually think of black holes as God's dumpster,
34:14but they really are actress on the galactic stage.
34:21The monster of the Milky Way may have helped create our solar system.
34:25But what's to stop it from wiping us out?
34:29It all depends on the monster's diet.
34:33One of the key differences between galaxies with supermassive black holes
34:37is whether or not their black holes are lit up,
34:39because they're basically binging on a lot of material in its surroundings.
34:46For years, our own black hole has probably been fasting.
34:50But in 1999, the Chandra Space Telescope detected a powerful signal from the galactic center.
34:57Station 3-4, Chandra, O.C.
35:00To let you know, we have about 18 minutes remaining in the playback.
35:04An explosion just outside the event horizon.
35:07For the galactic center teams, the blast is a wake-up call.
35:13It was a hot piece of news at the time.
35:16A remarkable fact for all of us was, for many years, how inactive the black hole was.
35:22Bit of a puzzle that there are so many of the blue stars on that side, not on that side.
35:26Now, both Reinhard Genzel and Andrea Goetz race to their telescopes.
35:31They will try to see whether the black hole's about to binge.
35:36The two teams join in a worldwide effort.
35:39Five major observatories will probe the black hole.
35:42From space, the Chandra X-ray Observatory will watch for high-energy light.
35:54Reinhard Genzel heads to Europe's Very Large Telescope, set in the high desert of Chile.
35:59Andrea Goetz climbs Hawaii's Mauna Kea volcano to the legendary Keck Observatory.
36:06When you're there, it's an incredible rush.
36:09You're very much on for the few nights that you're there, hoping that your experiment
36:14works, hoping that the weather cooperates.
36:18Telescope time is precious.
36:19There's no room for mistakes.
36:21We're ready to go.
36:25The teams have five short nights to find out how much the black hole is eating by measuring
36:30the energy that flares out.
36:33Night one.
36:34The Chandra headquarters in Cambridge, Massachusetts.
36:37Zoom in a little bit more.
36:39All right.
36:40So first night, doesn't look like we've got any flares.
36:45The telescope turns up only noise, X-ray flashes from small black holes roaming through the
36:50galactic center.
36:52Four more chances, guys.
36:56Night two.
36:57The telescope in Chile has problems.
36:59Can I see the monitor?
37:03I'm still not very much there.
37:04Well, we do need to sacrifice now someone.
37:10To the gods or something like this.
37:12Should I volunteer?
37:13Even if there are flares, the Very Large Telescope can't see them.
37:16We have to redo the acquisition.
37:17The correction was...
37:18Unstable.
37:19Yeah, unstable.
37:20A patch of humidity is warping the delicate optics.
37:21Everything's a blur.
37:22We need to change something because look at the guy's dark.
37:23We need to change.
37:24OK.
37:25Now we have a problem with the eight meter.
37:26With the main mirror, the eight meter mirror seems to be deformed.
37:41In Hawaii, it's not much better.
37:43The galactic center is playing hide and seek behind overcast skies.
37:48We're fighting with clouds.
37:50It looked better just a moment ago.
37:52So it looked like we were just ready to go, but now it's looking like...
37:59Finally, on night three, it's really flaring.
38:04The German team's luck changes.
38:06In Chile, they spot an outburst.
38:07It has been going on for more than an hour already.
38:10That's the best flare event that we saw during this run.
38:13A new point of light appears in the star field, one that wasn't there before.
38:18So here we clearly see that there's basically no source at that position.
38:22OK.
38:23Between those two plots.
38:24On the other side, we have the same region, and we clearly see that they're the same two
38:28sources, and now in between, we see an additional source.
38:31So this is the flaring state.
38:36When the Chandra team receive their data from space, they can see it, too.
38:40Oh, all right.
38:41All right.
38:42Here we go.
38:43Oh, yeah.
38:44There we go.
38:45That's huge.
38:46All right.
38:47That's at least...
38:48All right.
38:49So that's at least a factor of, like, 15 or so.
38:53So let's pick...
38:54The X-rays show a spike that coincides with the flash of light captured by the Germans.
38:59News from our colleagues, of course, telling us that they are a few hours further west.
39:05So the sun hasn't even set yet.
39:09The stars of the galactic center haven't yet risen above the Hawaiian horizon.
39:14Gett has missed the flare.
39:16This part kills me.
39:18Waiting.
39:20But the next night, the team gets what it's looking for.
39:23I like that image a whole lot better.
39:26This is it.
39:29Yeah.
39:31Really.
39:32We were taking measurements, and you didn't see anything from the black hole.
39:37All you saw was a star, and then, bam, it was there and bright.
39:41And 15 minutes later, it was gone.
39:43So that was our moment to make the measurement,
39:45and it was extremely exciting to know that we'd actually been able to catch it.
39:51One day, not long from now, these scientists hope to see the monster directly.
39:56By linking observatories around the world in a giant telescope
40:00powerful enough to peer deep into the center of the galaxy.
40:08What they will see is a dark specter framed by flashes of light.
40:12These are just flares compared with the monumental eruptions of its past.
40:19Our black hole had a wild teenage life.
40:23I'm pretty sure of that.
40:25It probably had jets.
40:27It threw lots of matter out.
40:29It had a grand old time, and now it's decayed into the old folks' home of the galaxy.
40:36But what would it take for the monster of the Milky Way to awaken?
40:41Could explosive jets of energy once again blast across our galaxy?
40:48The watch is on at the very ends of the Earth.
40:51Astronomers have come to the South Pole to monitor radio signals from the galactic center.
41:00They can see signs of a disaster in the making.
41:03A vast ring of gas is looming just beyond the Milky Way's central black hole.
41:11In time, it will accumulate 300 million suns worth.
41:18When the ring reaches a tipping point, it will begin to funnel into a second ring that orbits close to the center.
41:31The inner ring will condense into a giant cloud.
41:35Within it, a storm of new stars will be born.
41:42Then, the gas cloud will begin to spiral down into the grasp of the black hole.
41:47When the feasting starts, the eruption will be visible far beyond our galaxy.
42:01Our galaxy will survive its black hole's upcoming feast.
42:05But it isn't likely to survive a threat further down the road.
42:09Galactic cannibalism.
42:12Our galaxy, the Milky Way, is not immune from these colliding galaxy scenarios.
42:18We've got neighbors. We're falling towards each other.
42:22And one day we will collide.
42:25Even now, the end of our galaxy is approaching.
42:28Our giant neighbor, the Andromeda Galaxy, is charging toward us.
42:37Knowing the galaxy's dimensions, flight paths, and the laws of gravity,
42:41scientists can predict how the clash of titans will unfold.
42:51What our simulations show is what could happen basically in quite a few billion years from now
42:57when the two galaxies will actually approach each other and merge.
43:02First, the galaxies will circle and entwine, ripping each other apart.
43:08Imagine what that might look like from another galaxy.
43:11You'll see two grand, beautiful spiral galaxies moving towards each other, slowly losing their shape.
43:17You'll see new avenues where stars and gas can funnel down towards this newly formed center,
43:26feeding this reborn monster.
43:32The collision will send a blizzard of stars and gas billions of kilometers into space.
43:40Some will shoot toward the crowded core of the new galaxy, spurring even more massive explosions.
43:48Amid the turmoil, our little solar system will be flung into the voids of space
43:53and even more driven into the black hole's jaws.
43:57In the process of merging, there will be a very strong starburst event occurring at the time of the merger
44:07as all of the gas is being funneled towards the center,
44:11as well as the two black holes that are likely to merge will also swallow a lot of this gas.
44:20The black hole in our Milky Way will ignite, emitting so much energy that all of the gas around it
44:27will again be blown away in this very substantial wind and very substantial outflow.
44:34The Milky Way will be destroyed, but what about the black hole at the center?
44:42It will merge with Andromeda's.
44:51Stars and galaxies may come and go, but supermassive black holes just keep getting bigger.
44:58Once considered freaks of the cosmos, black holes may simply be the workings of a restless universe.
45:06As we forge ahead in trying to understand how we came into being
45:11and how all of the matter got put down in the universe,
45:15we can't leave black holes out of the picture,
45:17because it seems they play a fundamental role on very, very large scales.
45:24Black holes not only actively shape the landscape in which they're engaged,
45:28they wreak havoc upon it,
45:30throw in a hungry beast in the middle of it all,
45:34and it distorts the gas clouds.
45:36It flings stars hither and yon.
45:41It creates energy fields that would fry any life in its vicinity.
45:46That kind of makes the center of galaxies interesting places.
45:49Black holes are kind of the spice of the universe.
45:53They're a major player in the evolution of the things that light up our night sky.
45:57Even though we can't see them,
45:59they are in a sense the secret shadows behind the walls of the galaxies.
46:05Scientists today are bringing us closer to a shadowy presence of black holes.
46:10They are the most important part of the universe.
46:14Scientists today are bringing us closer to a shadowy presence
46:18that long ago erupted across our galaxy
46:21and shaped the universe we know.
46:23For the moment, the monster is resting quietly.
46:27But how long will we have to wait for it to rise again?
47:13Transcription by ESO. Translation by —