How to See a Black Hole | BBC Documentary
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00:00The universe holds a giant cosmic secret.
00:09Nobody has ever seen what a black hole really looks like.
00:15Now a team of international astronomers are on a mission to find out.
00:19Here we go, we're on.
00:24The team's director has dedicated his life to take the first ever picture of a black
00:30hole.
00:31If you ask why this hasn't been done before, it's because it's really, really hard.
00:36For two years our cameras have followed these scientists to the most hostile environments
00:41in the world.
00:43It's pretty cold.
00:44The wind chill right now is around minus 70.
00:47As they build a revolutionary telescope the size of planet Earth.
00:54If they succeed, a picture of a black hole will challenge the theories of Albert Einstein
01:00and could pave the way to a new era of physics.
01:04It will be one of the most thrilling discoveries of our age.
01:11This is the inside story of the mission to capture the first real picture of a black
01:18hole.
01:28Of all the wonders in our cosmos, one object has remained hidden to the greatest scientific
01:34minds.
01:38The black hole.
01:43A black hole is a region of space where the pull of gravity is so powerful that nothing
01:49at all can escape if it gets too close.
01:52And by nothing, I really mean nothing, including even light itself.
01:58What we really mean by that is this area called the event horizon.
02:02It's a specific limit around the black hole that marks what's inside and what's outside.
02:09Once anything crosses that boundary, adios.
02:13It is out of contact with the rest of the universe.
02:15We don't know what its ultimate fate is, but probably it ain't very good.
02:23Most scientists today believe that black holes really exist, but nobody has ever actually
02:30seen one.
02:34We have identified lots of objects that look like black holes, but you can't prove that
02:41they're black holes.
02:42This is where the problem comes, right?
02:46If nobody has ever seen a black hole, can we be sure that they really exist?
02:52Could this fundamental notion about our universe and how it works be wrong?
03:04Astronomer Shep Dolman is on a mission to solve this mystery.
03:11He's spearheading an extraordinary experiment.
03:15He wants to take the first ever picture of a black hole.
03:21The goal of the entire project is to see what a black hole really looks like and detect
03:26its shape and see what's happening immediately surrounding it.
03:32Just saying that gives me chills.
03:35I've been interested in black holes since I began doing astronomy.
03:39It's really kind of what got me into it in the first place.
03:42I kind of fell in with this crowd doing radio astronomy in a very special way.
03:54Here at the Haystack Observatory and across the world, Shep has been developing a technique
03:59to try and see the unseen.
04:06Shep is targeting the very center of the galaxy, where astronomers have detected a cluster
04:11of stars orbiting something strange.
04:18The stars are orbiting so fast, scientists have calculated the object must have the mass
04:26of more than 4 million suns.
04:31The best explanation, a black hole called Sagittarius A star.
04:38Shep wants to use radio telescopes to try and see this black hole, but there's a problem.
04:44Although it's predicted to be larger than the sun, from Earth, it's 26,000 light years
04:50away.
04:51This is such a small target, there's no telescope in existence that has the power to see it.
04:59The entire reason this hasn't been done up till now is that black holes are extremely
05:03small.
05:04They would be the equivalent of trying to see an orange at the distance of the moon.
05:09So we have to build a telescope, we have to build a fundamentally new instrument that
05:13can see things that are that small.
05:17To achieve this unprecedented power, for the last decade, Shep has been working towards
05:23a master plan.
05:26He wants to combine eight separate telescopes in Spain, Mexico, Arizona, Hawaii, Chile and
05:41the South Pole.
05:43This network is called the Event Horizon Telescope and spans the face of planet Earth.
05:50To capture the crucial image, all eight dishes must point towards the black hole at exactly
05:55the same time.
05:58We're linking telescopes about 10,000 kilometers apart, even more than that.
06:03By spanning the globe, you create a new kind of instrument that can see a black hole.
06:10That's the secret sauce, that's the secret of the Event Horizon Telescope.
06:20Each of the eight telescopes in the network are unique and powerful observatories.
06:30They can detect emissions from around the black hole, but the team will need to combine
06:34these signals to make an image.
06:37Across the world, the team will observe the black hole simultaneously and record the data
06:43onto hard drives.
06:46Then they must physically transport the drives back and combine the data inside a giant supercomputer
06:53called a correlator.
06:56This correlator is the final piece of the puzzle.
06:59The first part is collecting data at different spots around the globe.
07:04The second piece, though, is combining that data, and that's what the correlator does.
07:11Only then will this new earth-sized telescope have a chance to make an image of a black
07:17hole.
07:20If the Event Horizon Telescope manages to actually take a high-quality photo of a black
07:25hole, that's not an impressive feat.
07:28It's a mind-blowing feat.
07:30It's a technical tour de force like we've never seen before.
07:35But what does Shep's team hope to see if a black hole allows nothing, not even light,
07:41to escape?
07:47A black hole itself is invisible, but matter falling into it should give it away.
07:58Its intense gravity attracts interstellar gas and pulls it into a faster and faster
08:04orbit.
08:08This heats the gas to billions of degrees and emits the light that the telescopes should
08:14be able to detect.
08:18The mathematics suggests gravity will warp these emissions into a circular ring, leaving
08:24in the center the shadow of the black hole.
08:32It's an important scientific prediction.
08:34If the team sees something that isn't circular, it could turn the most treasured theory in
08:40physics on its head.
08:45Einstein's theory of general relativity.
08:49This theory says mass curves the fabric of space and time, creating an effect that we
08:55call gravity.
08:59Einstein's theory of relativistic gravity is what lays the foundations that sets all
09:04of our understanding.
09:06Step one is just, did Einstein get it right?
09:09Is there some detail that's been overlooked?
09:11For a hundred years, Einstein's theory has passed every test.
09:17But nobody has ever seen its most extreme prediction.
09:22If enough mass could be crushed into a single point, its gravity would be so strong it would
09:28form a black hole.
09:31How wonderful would it be if the Event Horizon Telescope shows us that in extreme realms,
09:39Einstein is not completely right?
09:41It will be one of the most thrilling discoveries of our age, as we will then leapfrog forward
09:47in our grasp of how the universe works.
09:51A challenge to Einstein's theory, and a new era of astronomy rests on the success of the
09:57Event Horizon Telescope team.
10:09There are now just three months until the team will attempt to observe a black hole
10:13using a network of eight telescopes.
10:16But there's a lot to do.
10:20Shep has come to Mexico to oversee a crucial test run using four of the eight telescopes
10:26in the network.
10:29What really gets us out of bed, what really gets us motivated for this, is building a
10:35new kind of instrument.
10:37When you think of building a telescope as large as the Earth, that in and of itself
10:42is such a crazy idea.
10:45To link the telescopes, the team will use a technique called Very Long Baseline Interferometry,
10:52or VLBI.
10:53But it poses a major challenge.
10:55During the observations, they won't see any results in real time.
11:00The very nature of the technique we're using is that we're not going to know if these observations
11:06work until we get all the data back to a central processing facility.
11:11So we're here to do what's called a dry run, to make sure that everything runs like clockwork.
11:23We have crack ninja teams here in Mexico, Chile, the South Pole, Spain, and they all
11:30know their business, frankly.
11:32They know what to do.
11:34You check everything, and you check it again, and you check it three times.
11:39During the critical observation run, there's a lot that can go wrong.
11:50The radio emission from the black hole must be recorded at each telescope, and the data
11:55stored onto specialized hard drives.
12:00Clouds can obscure the signal, and equipment could fail, knocking one or more of the telescopes
12:07out of the network.
12:10So the team need clear weather and perfectly working telescopes at every location across
12:15the globe, simultaneously.
12:19If just one telescope fails, they might not get an image.
12:25After the data have been recorded, the filled hard drives will be shipped to Massachusetts
12:30and Germany, where the data must be combined, and they will know if their ambitious plan
12:36has worked.
12:37You think it's all set?
12:40I hope so.
12:42In Mexico, astronomer Gopal Narayanan is in charge.
12:46The whole purpose of the test observations we're doing is to bring in a couple of new
12:51facilities.
12:53We're going to bring in OPEX, which is in Chile, PICO, Vivaleda, in Europe, and the
12:58South Pole Telescope.
13:04The South Pole is a critical location for the team.
13:09Its clear, frozen skies are perfect for observation.
13:15But flights here will soon stop for the winter, which means the data from the South Pole will
13:20be the last to return.
13:25Instrument expert Dan Maroney and his team have traveled here to the ends of the Earth
13:30to get the telescope ready.
13:31By including the South Pole Telescope, we really, truly make a telescope the size of
13:35the Earth.
13:36It more than doubles the resolution of the array and gives us that last bit of detail
13:41that we need to make a picture of a black hole.
13:46It's January, and the weather is abiding 36 degrees below zero.
13:51So it's pretty cold.
13:52The wind chill right now is around minus 70.
13:57Despite the cold, the team still need to prepare for the test observations.
14:05They must install this custom-built mirror to the telescope with sub-millimeter accuracy.
14:10Okay, I do believe the tertiary is installed.
14:15We have to have this mirror positioned so that the light from this giant 10-meter telescope
14:21is focused precisely on our receiver.
14:24So that took a little bit of doing, but we think we have it right about now.
14:28The mirror is in, but until the observations are complete, they won't know if it's worked.
14:40Back in Mexico, Gopal and the team get ready to start the trial observation run with the
14:45four telescopes.
14:47They will observe bright sources called quasars to help test the new network.
14:55Data specialist Lindy Blackburn is in charge of recording the data.
14:59One minute to go.
15:00One minute to go.
15:02Is Lindy happy with this?
15:04Here we go.
15:07We're on.
15:09But as the test observations begin, there's an unexpected problem.
15:21A bug in the code means the recording lights are not coming on.
15:25No, it's trying to record.
15:27Oh, it's trying to record.
15:30Sending data to record, only the very last step in this whole fine process, which is
15:35probably a very important step, which is to record the data we've collected all through
15:39the chain.
15:40That is not happening right now.
15:43Without data, the telescope is knocked out of the network.
15:48Lindy is working furiously to find the fixes, and I think we're hopeful.
15:55So the IF levels look fine.
15:56Yeah.
15:57Tell me it's working, Lindy.
15:58No.
15:59No.
16:00Same problem.
16:01I changed the order when I thought it was the initial problem with the...
16:10You're hoping that we'll get this recording this time, Lindy?
16:14I really don't know.
16:15One minute.
16:16Already?
16:17Ten seconds to go.
16:18Lights.
16:19Yay!
16:20Good job, Lindy.
16:21It's 2.46 a.m.
16:22The team have succeeded in recording the test data, but they won't find out if it's
16:41worked until the data have been analyzed.
16:46Only then will the team know if they stand a chance on the real observation run, when
16:52they attempt to record an image of a black hole.
16:59An image of a black hole will provide a new way to test Einstein's most extreme theoretical
17:05predictions.
17:07Einstein's equations show us that if you spend an hour or two at the edge of a black hole
17:11and then come back to Earth, for instance, Earth might have aged 10,000 or a million
17:16or a billion years.
17:18So when we are observing the event horizon of a black hole, we are observing what really
17:22can be characterized as a time machine.
17:26Yet despite Einstein's equations, even he didn't think that black holes could exist,
17:33that nature could ever allow them to form.
17:36That's a sensible objection that Einstein had.
17:38I mean, after all, it would be very, very, very hard to do, to crush all the mass of
17:43something to a point.
17:45Einstein naturally and reasonably assumed that matter just wouldn't allow itself to
17:50be compacted that much.
17:53But evidence of a mechanism has been growing.
18:02Scientists now believe a black hole is the corpse of a giant star that's gone supernova.
18:12Deep inside the debris, the surviving core collapses to an infinitely small point.
18:20This is called the singularity.
18:24Its intense gravity warps space and time so severely that nothing can escape, forming
18:29a black hole's event horizon.
18:33It's possible that black holes are ultimately a figment of the mathematical equations that
18:38Einstein gave us.
18:40But how better to begin to push this understanding than to look and see what's actually out there.
18:45And that's the promise of the event horizon telescope.
18:50The team hoped to test these theories by taking a picture of the black hole at the center
18:56of our galaxy.
19:00But they have an even bigger target, a black hole in the center of a different galaxy called
19:05M87.
19:06There are only a couple of targets in the universe currently where the event horizon
19:13telescope can hope to resolve this silhouette of a black hole to see the edge of the event
19:18horizon.
19:19M87 is one of them.
19:21This image of M87 is the closest astronomers have come to seeing a black hole.
19:27But to see its edge, Shep must zoom in much further.
19:32If we want to image the event horizon, we have to make an image of what's inside this
19:37little box here at the very central core of this galaxy.
19:41That's what we've been directing all of our efforts towards for over a decade, to find
19:46out what happens in this place that has been off limits to us since the beginning of astronomy.
19:53If they succeed, computer simulations show they should see this.
19:59Light bent into a ring and the shadow of the black hole.
20:05If we could see this ring, it would be the best evidence that we have for the existence
20:10of black holes.
20:16There are now just two weeks to go until the team will attempt to observe the black holes.
20:25And they're still working their problems.
20:31In Europe, Dutch astronomer Remo Telanus is in charge of managing the logistics of this
20:36global project.
20:37Hey, morning.
20:39How are you guys doing?
20:42I like that.
20:43That is what you guys did.
20:45The monitor.
20:46It looks very good.
20:50It's taken two months for the team to process the test run data, but the results are finally in.
20:57I know.
21:00Some nice results to show you.
21:02The data shows the telescopes have successfully linked together.
21:06Even though they're apart by thousands of miles, they actually observe this source exactly
21:12at the same time.
21:13We did have problems because the South Pole Telescope, it has moved by about 20 meters
21:17because the whole ice sheet moves.
21:20That's quite unusual.
21:21I think there's no other telescope which does that, actually.
21:22I hope not.
21:23I certainly hope not.
21:24We're in trouble then if that happens.
21:27That doesn't mean that the job is quite done yet.
21:29There are a few technical issues we need to take care of, but the core system works.
21:35It's good news for the team.
21:37But Heino Falcke, one of the project's leading physicists, knows how difficult linking all
21:42eight telescopes will be.
21:44If you go to these extreme experiments, you have to be extremely precise and take everything
21:49into account.
21:50You need to know the position to a fraction of a millimeter precisely.
21:54If you look at Hawaii, this is a volcanic region.
21:58This actually shifts due to plate tectonics by six centimeters per year.
22:03But if you go to the South Pole, there's ice and that flows.
22:08And this can move by meters, 10 meters sometimes within years.
22:12So this really is the Formula One race car of the telescopes moving positions.
22:17And of course, let's not forget, you know, away from the Earth is the moon.
22:22And that actually, it's affecting the entire globe.
22:25So some of the telescopes actually will be pulled by the gravity of the moon into one
22:29direction.
22:30They move half a meter up and down every six hours.
22:35With such incredible precision needed, the team need everything to go to plan.
22:40Any telescope you lose will already significantly compromise your result.
22:45It will still be interesting.
22:46It will just not be an image.
22:47It will be some data and some plots that you show.
22:50It will not be an image.
23:01Some of the others are very nervous.
23:03I believe that they absolutely want to get the picture this year.
23:09But I'm more relaxed.
23:11I find it exciting just to be at the point that we can try to do this.
23:18Remo has come to the Max Planck Institute for Radio Astronomy in Bonn to check the team's
23:23preparations.
23:27Here, hardware specialist Alan Roy is facing a problem that could jeopardize the entire
23:32project.
23:36Hey, Alan.
23:37Hi.
23:38Good to see you.
23:40How are you doing?
23:41Did you have a good trip?
23:42Yeah, I had a good trip.
23:43It was fine.
23:44Oh, man.
23:45So it's happening here.
23:46Thermal problems.
23:47Yeah.
23:48The machines that record the data are overheating.
23:51The problem with the recorders we have at the moment is they're getting too hot inside
23:55and they're shutting down.
23:58If that happens in the run, then that would stop us in our tracks.
24:03The observations we're making depends on having the whole array present.
24:09The problem is high altitude.
24:14The thin air at the telescopes means the cooling system is less effective.
24:19So Alan needs to make metal plates to deflect more cool air over the electronics.
24:27It's looking good.
24:28Let's see.
24:34So, let's see if it fits.
24:38Always a moment of tension, even in simple things.
24:42And yes, perfect.
24:47Across the hall, Helge Rotman is in charge of over 500 hard drive units that can store
24:54millions of gigabytes of data.
24:57Disk modules, they really contain the essence of what we want to do.
25:01The specialty about these, they are helium-filled disks able to operate at very high altitudes.
25:08In terms of operational costs, this is the main factor.
25:11So buying disks is expensive.
25:13For example, we cannot afford to back up any data.
25:17And if it gets lost or broken, we practically lose that data, which is quite catastrophic.
25:22That's my nightmare, that we'll have like a whole pallet full of these and they drop
25:26the pallet.
25:27That is just going to be horrible.
25:31Remo must send the drives to each telescope location.
25:36It's just one small part of this global logistical feat.
25:40It's now 8 p.m. and Remo is running a teleconference with the rest of the team.
25:45The next issue I think I want to tackle is the outstanding tickets that we still have
25:50before we get to the observations.
25:53Just two weeks away from the observations, the pressures and tensions of the project are mounting.
25:59The schedule starts at 3 p.m. local time at 0100 UTC.
26:05There's nothing we can do about it anymore.
26:07I mean, these were discussed and have been discussed.
26:10So the schedules are what they are.
26:13Just assume that it's going to be OK.
26:15All right.
26:16There's nothing we can do about it.
26:17No, no, I realize that.
26:18OK, that's it, guys.
26:19Thanks all.
26:20We'll be in touch.
26:21Bye.
26:22OK, bye.
26:23Thanks, bye.
26:24It's taken 10 years to pull all these telescopes into the array, to equip them.
26:30We're all motivated by the same thing.
26:32We want to see that black hole and that is ultimately what drives us.
26:37Get a glass of wine and go to bed.
26:39Seriously, that is what I now want to do.
27:02There's now just one day to go before the make-or-break observations to photograph a black hole.
27:10So move it here.
27:12Imagine we had it kind of open.
27:15In Massachusetts, chef and physicist Demetrius Saltis are setting up a central communications hub.
27:22Yeah, to have space around something like that.
27:27What do you see?
27:28Now you're talking.
27:29Now you're talking.
27:32This will be mission control.
27:34Communication is vital to the entire project.
27:37I mean, we're synchronizing things to a microsecond.
27:40We need to make sure that everything is set up.
27:42We need to make sure all the tests have been run.
27:48The team need to link eight world-leading, multimillion-dollar observatories simultaneously to capture that image.
27:56We've got clear blue skies, so...
27:59They have a ten-day window at the telescopes,
28:01but clouds at any one of them could obscure the signal from the black hole and ruin the data.
28:09So each day, Shep needs to make a call.
28:11If the night is go or no-go.
28:15Whether or not you energize the Event Horizon Telescope on a given night,
28:19that's the biggest decision you can make.
28:21If you make the right one, then you've got great data.
28:25If you make the wrong decision, you've expended huge amounts of resources.
28:29Each night of observational will not only cost thousands of pounds,
28:33but also eat up their limited hard-drive space.
28:37Shep needs five nights of data to stand the best chance of making an image.
28:43Judging the weather conditions across the world will be critical.
28:47People might go above in the next couple of days.
28:50The armor looks good.
28:52If you make the wrong go-no-go decision,
28:54you may have jeopardized your ability to image a black hole.
28:58And that's what consumes us when we're in that room.
29:04The communication and weather reports are online.
29:07Now Shep needs to make sure the telescopes are ready.
29:11We want to make sure that we understand where things stand by the end of today.
29:14Because if something is not technically ready, then we really do have a problem.
29:22In Hawaii, the volcano Mauna Kea is home to two observatories in the network.
29:30The James Clark Maxwell Telescope and the Submillimeter Array.
29:38Remo has arrived from Europe, but the equipment still isn't ready.
29:47Hey, Jonathan.
29:48Hi, Remo.
29:49How's it going?
29:50Not too bad.
29:51Lead engineer Jonathan Weintraub is still fitting the new cooling kits to his set of data recorders.
29:58It was installed on Thursday, and then we were like, oh damn, it doesn't have a cooling kit.
30:03Oh, yeah.
30:04So we're putting in the...
30:06Yeah, it's a proper just-in-time management, I guess.
30:09I guess, yeah.
30:10This is kind of last minute.
30:13This is kind of preventative maintenance.
30:16We don't want to suffer a failure due to overheating in the middle of the run.
30:23Yeah, now the light turned on.
30:24Here we go.
30:25Yeah.
30:26And there's air blowing out of these fans.
30:28Yep.
30:29Excellent.
30:35Okay, slide them in.
30:38Remo and Jonathan must install the recorders and check they are all working.
30:43Okay, there we go.
30:44That's it.
30:46More discs are there.
30:48Yep.
30:49All of them show up.
30:50Right.
30:51The very act of powering down and then powering up is to some degree stressful.
30:56I mean, sometimes you power something down and it never works again.
31:01So, you're always relieved when something works.
31:05Whilst things are back on track in Hawaii,
31:10high in the Atacama Desert of Chile,
31:16Alan Roy has arrived from Germany to lead the observations at APEX.
31:21Atento, Guardia de Control, APEX 2, APEX...
31:26Here, Alan is responsible for the most critical part of the project,
31:30the timing.
31:32Timing is absolutely important to this project, absolutely central.
31:35It's the heart piece of the whole experiment.
31:39You're putting in a lot of effort, a lot of money, a lot of time,
31:43and it's all hinging on getting that timing right.
31:48The Event Horizon Telescope network is so large,
31:51the emission from the black hole will arrive at each telescope
31:55at a different point in time.
31:57What's more, the Earth rotates.
32:00As it spins, the position of the telescopes in space constantly changes.
32:05If the team can't record the time the signals arrive
32:08to within a millionth of a millionth of a second,
32:12the telescopes will fail to combine as one.
32:18To sync the telescopes together,
32:20the team have spent two million dollars
32:22on some of the most expensive telescopes in the world.
32:26They've spent two million dollars
32:28on some of the most accurate atomic clocks in the world,
32:31called hydrogen masers.
32:34This is the hydrogen maser.
32:36This clock keeps time to about a second in ten million years.
32:40Of course, we don't wait ten million years to measure it.
32:44Alan must keep this clock at a stable temperature
32:46so it can run precisely.
32:49But there's a problem.
32:51The chamber used to cool it is broken.
32:54So that means the chamber overheats
32:56and the maser is then not very happy.
32:59A faulty maser could be catastrophic.
33:05In the remote Atacama desert,
33:07it's too far to call out an engineer.
33:10Alan has only one improvised option available.
33:13The solution is to crack open the door of the chamber
33:17so that the excess heat from the maser
33:19can come out through the door.
33:22It makes me a little nervous,
33:24but the clock we have to take on faith,
33:26yes, that it's running as it should.
33:30For now, this resourceful solution
33:32has to keep the clock running correctly
33:34or the whole experiment could be at risk.
33:38My hat is off to the folks
33:40that can actually undertake
33:42these experiments and observations
33:44and make it work.
33:46It's real, it's tangible
33:48and it's extreme and abstract at the same time.
33:51There's always a risk with these kind of measurements.
33:53They're difficult things.
33:55It's required so much care and finesse
33:57to bring all these pieces together.
34:02Remarkably, the weather is clear
34:04at all eight telescopes.
34:07In Hawaii, Remo hears from mission control.
34:11So, just got the news.
34:13It's a go.
34:15It's a go.
34:17So, just got the news.
34:19It's a go.
34:21Ready to go and start observing.
34:26This is the crucial moment
34:28that over ten years of hard work
34:30has been leading up to.
34:32It's taken a long time to get to this point
34:34that we're going to give it a real shot
34:36to get an image of a black hole.
34:38And now, finally, the day is here.
34:43Remo must descend to over 4,000 metres
34:46to the top of the volcano.
34:50He had two observatories.
34:52The James Clark Maxwell Telescope
34:54and the submillimetre array
34:56are part of the network.
35:00And Remo is up against the clock.
35:06Right.
35:10We have to start tuning the receiver.
35:12This mirror directs the radiation
35:15into the receiver that we're going to use.
35:17It's like tuning your radio.
35:21It's going.
35:23Looking good.
35:25At the submillimetre array,
35:27engineer Jonathan Weintraub
35:29is in charge of recording the data.
35:31We have 50 minutes now
35:33to run the checks before we start reporting.
35:35And high altitude doesn't
35:37help your brain function.
35:39You tend to make more mistakes
35:41at altitude.
35:44But across the mountain,
35:46Remo hits a glitch.
35:48Oh.
35:50What the heck?
35:52He fell out of lock.
35:54The receiver won't lock onto the frequency.
35:58Without a lock,
36:00the data from the telescope
36:02will be ruined.
36:04Maybe our gig is unlocked.
36:06Remo has no option
36:08but to manually adjust
36:10the receiver settings.
36:13I might now need reading glasses.
36:15I can't see their stupid dials anymore.
36:21Yeah, we stayed in lock.
36:23Excellent.
36:29The team is ready,
36:31just in time.
36:33Good.
36:35Wait.
36:37It has a nice signal.
36:39Attention, attention.
36:41Roof will be opening.
36:43Doors and roofs will be opening.
36:45Call station 42.
36:53It is open.
37:01Remo directs the dish onto the target.
37:05And Jonathan gets ready
37:07to record the data.
37:103, 2, 1.
37:12Are we going?
37:14The event horizon telescope is on the way.
37:18After over 10 years of work,
37:20the teams at eight
37:22different observatories
37:24are finally fixing their gaze
37:26on a black hole.
37:36The team observed the emission from black holes
37:39and record data
37:41late into the night.
37:43After a 14-hour shift,
37:45Remo must leave
37:47to avoid altitude sickness.
37:49It's getting close to our 14 hours
37:51on the mountain.
37:53You're getting tired
37:55and I will go down to the day facility
37:57which is a little bit lower
37:59but I will be sitting and monitoring
38:01for quite a few more hours
38:03but at least there will be more oxygen there
38:05so that will help.
38:08The rest of the night. We'll see you tomorrow.
38:10Cheers.
38:12Over the first two days of the run,
38:14the eight telescopes around the world
38:16record two full nights of data.
38:24But in these extreme locations,
38:26the physical as well as mental challenges
38:28are taking their toll on the team.
38:32It's hard physical work each day
38:34and you feel it constantly on your body.
38:37The pulse rate is constantly elevated at altitude
38:39and there's constant stress on the system.
38:43We're tired.
38:45You know, you wind up
38:47just being up at all hours of the night.
38:49People at high altitude
38:51are not always thinking perfectly.
38:53Where is it?
38:55Oh, so it's in front.
38:57We had a problem.
38:59One of the telescopes,
39:01one of the bits of electronics
39:03that we rely on,
39:05look at channel number 17.
39:07And ultimately we fixed it
39:09because we were in the room.
39:11We're working.
39:15So far,
39:17the weather has been perfect across the globe.
39:19But on day three,
39:21at the Large Millimeter Telescope in Mexico,
39:23the outlook is beginning to change.
39:27It's a scary, scary webcam.
39:31You know, the LMT is just completely chaotic right now.
39:34I mean, you saw the webcam.
39:36There's softened by fog.
39:38There's clouds rolling in.
39:40It looks very, very dicey up there.
39:42It is. It's clearly building up.
39:54I mean, I'm not going to candy-coat it for you guys.
39:56The decision
39:58for tonight largely rests
40:00with you.
40:03It's a fool's game, right?
40:05You can't predict the weather 10 hours from now.
40:07Especially the top of an extinct volcano
40:09with a big telescope on it.
40:11We got real solid,
40:13good weather
40:15at one, two, three, four, five,
40:17six of our sites.
40:19Six out of eight.
40:21Those are tremendous, tremendous odds.
40:23Two of the key sites,
40:25they're marginal.
40:27The telescope in Mexico,
40:29the LMT,
40:32and the telescope in Arizona
40:34have dicey weather.
40:36And so we're just going to wait.
40:42Shep delays the go, no-go decision.
40:44It's too close to call.
40:46You guys have to explain
40:48these LMT webcams to me.
40:50From one direction,
40:52it just looks like a vacation paradise.
40:54And then for these other views,
40:56it just looks like
40:58you're heading into a vortex maelstrom
41:01of hell.
41:03And I don't understand how three different views
41:05can be so different.
41:07Shep has to decide.
41:09But now there's news
41:11from the ALMA observatory in Chile.
41:13Hold on, hold on.
41:15I want to make sure I understand what you just said.
41:17You think there's a chance
41:19that the data from last night are
41:21from ALMA are corrupted?
41:25There's a chance.
41:27Their entire second night
41:29of data
41:31could be corrupt.
41:33This is a whole new
41:35wrinkle for us.
41:37If you had extra time,
41:39could you run this problem down?
41:41Running it down is probably
41:43not likely.
41:45If the data are corrupt,
41:47the team might now only have one night
41:49out of the five they need.
41:53With the weather set to get worse,
41:56Shep has to take a risk.
41:58I think we should make this a go
42:00because we're not going to tear the system apart
42:02so we have to assume that ALMA is going to be fine.
42:04So I'm going to say
42:06that we're going to go.
42:14Over the next four days,
42:16the team let the storm pass
42:18and observe for another two nights.
42:20We are recording the data.
42:26Their hard drives fill up with over 6 million gigabytes
42:28of precious data.
42:30More storage
42:32than 12,000 laptop computers.
42:38If the team can make an image,
42:40it could unravel one of the biggest
42:42mysteries in physics today.
42:50What lies at the very center
42:52of a black hole?
42:56Einstein's equations suggest
42:58it's an infinitely small and dense point.
43:00The so-called singularity.
43:04A singularity is a physicist's
43:06way of saying we do not know what the heck
43:08is going on.
43:10In reality, at the dense
43:12core of a black hole,
43:14Einstein's equations don't make sense.
43:16If you take
43:18Einstein's mathematics seriously
43:20and apply it right to the center
43:22of a black hole, then you do have
43:24an infinite density.
43:26But there's no meter in the world
43:28that when you measure something
43:30goes infinity.
43:34Nature is kind of
43:36grabbing us by the lapel
43:38and slapping us in the face
43:40and saying you don't understand what you're doing
43:42if infinity is cropping up
43:44as the answer.
43:46Right now, frankly,
43:48the interior of a black hole
43:50is the Wild West of physics theorists.
43:52But the good news is
43:54if you have a theory that predicts something different
43:56from Einstein, from what happens inside,
43:58there's a good chance it also predicts
44:00something different from what happens immediately outside.
44:02It's just so
44:04exciting to finally, hopefully start
44:06getting some clues from
44:08the Venterisen telescope.
44:12A picture of a black hole will take theory into reality.
44:16It could be the best physical evidence
44:18scientists have
44:20to figure out the mysteries deep inside.
44:22And could pave the way
44:24to a so-called theory of everything.
44:34It's seven days
44:36into the run.
44:42At mission control,
44:44the team must now decide
44:46on what could be the final night of observation.
44:48This will be our fifth night.
44:50And this way we'll have
44:52OPEX and ALMA
44:54at one end of a very sensitive baseline
44:56with really good weather at the other end of the baseline.
45:00The weather looks clear around the world.
45:02Alright, so we're a go for tonight.
45:04Everybody,
45:06let's make it count.
45:08Music
45:16For the last time,
45:18light from around the black holes
45:20is being recorded.
45:24In Chile,
45:26Alan Roy and the team finish
45:28what's been a tiring eight days.
45:30This is coming up to the end
45:32of the last run. We've got maybe three minutes.
45:34I'm feeling weary but
45:36content.
45:38The team have recorded their target
45:40of five nights of data.
45:42But only when they combine
45:44all the data together,
45:46will they know if they can see a black hole.
45:48This is the interesting part.
45:50This is
45:52almost a game of bluff.
45:54You've now spent
45:56more than a week here at the telescopes,
45:58observed through the night,
46:00and we still don't know if anything will come out of this.
46:06Music
46:08Back at mission control,
46:10Shep is reflecting on the team's
46:12extraordinary accomplishment.
46:14This is the beginning
46:16of the end, right? I mean, this is
46:18not the end by any stretch
46:20of the imagination.
46:24Even though we have all these disks,
46:26they could get lost in the mail.
46:28There are no backups.
46:30It's very, very difficult to copy all this data.
46:32So, you know, we're just a little
46:34nervous about some of that.
46:36You know, we have
46:38a lot of work to do. A lot of work to do.
46:40But we've taken this
46:42first big step.
46:46We humans
46:48love exploring things to the limits
46:50of what's possible. And the
46:52Event Horizon is the ultimate limit.
46:54I look at the audacity
46:56and the bravery, frankly,
46:58of the people who came up with a way
47:00of actually taking this incredible challenge
47:02and turning it into something
47:04that they are measuring today.
47:06It's mind-boggling.
47:18At the South Pole,
47:20after five months of winter darkness,
47:22flights resume
47:24once again.
47:26Now the team can ship
47:28the last remaining hard drives,
47:30holding the precious black hole data
47:32back to Massachusetts and Germany
47:34and complete the
47:36processing from all eight telescopes.
47:38This is where a lot of the action
47:40has been because
47:42all the drives
47:44that you see here came from all over
47:46the globe. All the EHT sites
47:48have sent their drives here.
47:50And this correlator has been crunching
47:52through all of these
47:54drives.
47:56Five months since the observations,
47:58the team can finally see
48:00if the telescopes linked together.
48:02This one's from Spain.
48:04This one's from Hawaii.
48:06This one's from Mexico.
48:08So you're really seeing kind of like
48:10a U.N. of the astronomy world here.
48:12We're basically
48:14taking the light that was recorded from
48:16these sites out of the deep freeze,
48:18reanimating it,
48:20and then combining it as though
48:22it was being combined for the first time.
48:24A data expert,
48:26Vincent Fish, finds a problem
48:28with the timing.
48:30This cannot be right.
48:32You're sh***** me.
48:34I'm amazed that nobody
48:36finds this at reserve time.
48:38Oh, sweet Jesus.
48:44They have discovered one of the network's
48:46atomic clocks in Spain was faulty.
48:48You're really getting
48:50just random noise here.
48:52We're pushing
48:54really the recording
48:56and the technology
48:58and the resolution to its absolute limits.
49:00And when you push something
49:02to the limits like this,
49:04you start uncovering these problems.
49:06There is a fix to this.
49:08I think we can correct for it
49:10so we don't face this problem again.
49:12Wow, look at this.
49:14This is the
49:16delay.
49:18The delay.
49:20Whilst the team
49:22resolve the timing glitches,
49:26in Cambridge,
49:28scientists from Arizona,
49:30Europe, and Japan have come to test
49:32how to turn the new data
49:34into images.
49:36The big challenge that we face in this technique
49:38of the Event Horizon Telescope is that we don't have
49:40all the pixels in the image, if you will.
49:42We have some of the pixels,
49:44so the art is trying to figure out
49:46what the entire image looks like
49:48without having
49:50everything that we'd like to have.
49:52The team will test
49:54different computer algorithms to see
49:56if they can create an accurate image.
49:58But they won't
50:00attempt it on the target black holes just yet.
50:02First,
50:04we're putting on training wheels.
50:06We're taking baby steps.
50:08And we're trying to use the algorithms
50:10that we want to use
50:12for SAG-JSTAR and M87,
50:14but on well-known sources that are much brighter.
50:18These bright sources come from
50:20matter swirling into what's believed
50:22to be a feasting black hole.
50:26As the black hole accelerates the matter,
50:28it rips it apart
50:30and launches jets of radiation
50:32into space.
50:34These are quasars.
50:36They can kick out
50:38more energy than a billion stars,
50:40leaving a signature jet
50:42that's visible across the cosmos.
50:46If we can
50:48get really good images
50:50on those sources,
50:52then we know we'll be ready to go to the next phase.
50:56Imaging scientist Katie Baumann
50:58is leading one of the teams
51:00trying to make an image of the quasar.
51:02It's really exciting. The first time we're actually
51:04trying to make an image with the data.
51:08The quasar is too far away
51:10to see the black hole itself.
51:12But the team know
51:14what the jet should look like
51:16from existing telescopes.
51:22But two days into this workshop,
51:24the algorithms are not producing
51:26one consistent image.
51:30I can make an image that looks like that,
51:32and that's ridiculous.
51:34We get a lot of different kind of structures come out
51:36from the same data.
51:38But I vote of confidence in those images, I guess.
51:40Physicist Mareki Honma
51:42is also not getting a clear image.
51:46Here is a very bright spot,
51:48so we believe there is something.
51:50But the whole area,
51:52it just looks like noise.
52:00If the team can't get the algorithms
52:02to work for the quasar,
52:04they won't be able to make an image
52:06of the black hole.
52:14The team worked for a week adjusting
52:16the computer code.
52:18Finally,
52:20the algorithms start to work.
52:22And the team can see
52:24the quasar jet in more detail
52:26than ever before.
52:28I see this jet-like kind of structure
52:30shooting out.
52:32It's incredible.
52:34The team
52:36has produced images
52:38now after going through this whole pipeline
52:40that seem very robust.
52:42So that's the key.
52:44You have to be so confident in your techniques
52:46and your data handling
52:48that you trust them.
52:50Because for SAGESTAR, for M87,
52:52we have no idea what we're going to see.
52:58After over 10 years of planning,
53:04over 30 million pounds,
53:06and the combined brainpower
53:08of over 200 international scientists.
53:10Attention, attention.
53:12Doors and roof will be opening.
53:18Finally, the time comes
53:20to try and make an image
53:22of a black hole.
53:24This has been a huge process,
53:26a very, very careful process.
53:28And the imaging team is now getting
53:30the first set of data they can use
53:32to make a photo of a black hole.
53:36It's really exciting.
53:38We just got the data,
53:40and that's, you know,
53:42what we've been waiting for for many years.
53:44So it's a pretty exciting time for us.
53:48This is the moment
53:50when we finally get to see
53:52what a black hole might look like.
53:54Each member of the team
53:56loads the data and starts
53:58running their algorithms.
54:00Are we going to, are we doing this?
54:02Okay. Ready?
54:04Set?
54:06Go. Going, going, going.
54:18The algorithms
54:20are producing some tantalizing images.
54:24This is very early stages.
54:26This is exploratory surgery.
54:28We've opened the patient up.
54:30We're looking inside. We're trying to find out what we see.
54:36Each member of the team needs to zero in
54:38on one consistent image.
54:44That is interesting.
54:48Whoa.
54:50I'm getting something very similar, a little bit.
54:54And with the data for the black hole M87,
54:56one image soon becomes clear.
55:02I see
55:04a circle-y feature.
55:10An image the likes of which
55:12astronomers have never seen before.
55:18What I'm seeing on the screen here is
55:20pretty startling.
55:22This is a case where
55:24the signal is so clear
55:26that it kind of hits you on the head with a hammer.
55:28If this holds up,
55:30it's going to be the discovery
55:32of my lifetime, and I think of
55:34many other people's lifetime.
55:36And
55:38it's really
55:40sobering to see what a
55:42black hole looks like for the first time.
55:46The image shows photons of light
55:48being bent into a ring
55:50by the power of gravity.
55:52In the center,
55:54a black hole with a mass of
55:56six billion suns is
55:58swallowing the light that strays too close.
56:00It is profound
56:02evidence that confirms
56:04the existence of black holes,
56:06first predicted by Einstein's
56:08theory of gravity.
56:10This shows us that space-time
56:12is distorted
56:14in the way that Einstein
56:16felt it would be at the black hole boundary,
56:18at the most extreme environment
56:20in the universe.
56:22These photons are struggling
56:24to get away from this black hole.
56:26And the black hole
56:28is tethering them with its
56:30immense gravity.
56:32And every once in a while
56:34some of them can just
56:36get away from the black hole and come to us.
56:38So we're seeing the very definition
56:40of this surface
56:42where
56:44light is lost forever.
56:50In 2019,
56:52the Event Horizon Telescope
56:54team verified
56:56their data and released their results
56:58to the world.
57:10This is a groundbreaking
57:12scientific result.
57:16But with plans for more
57:18telescopes and even better data,
57:20a picture of Sagittarius A
57:22star could soon be next.
57:24When Galileo first
57:26proved that you can take pictures
57:28of the sky with telescopes,
57:30that didn't end astronomy.
57:32It started it.
57:34And in the same way,
57:36the most important
57:38scientific legacy of the Event Horizon Telescope
57:40is going to be the fact that it creates
57:42an entirely new field of science.
57:45If I know astronomers,
57:47when this thing is done, they're going to go,
57:49what else can we do with this?
57:51I can certainly envision
57:53that 10, 30, 50 years
57:55from now, our description of black holes
57:57are going to be completely, radically
57:59different.
58:01Porschepp and the Event Horizon
58:03Telescope team,
58:05they hope this is just the beginning.
58:07We're not done.
58:09We don't actually like things to be
58:11tied up with a bow and finished.
58:14This shows us how
58:16black holes eat and how they feed
58:18in a way that has been impossible
58:20up to now.
58:22This most of all
58:24signals a whole new direction
58:26in astronomy.
58:28And that's rare.
58:30That is really extraordinary.
58:34Coming up, the flexibility
58:36of the spine giving us vast freedom
58:38of movement. Secrets of bones
58:40are uncovered here on BBC4 Next.
58:44Sound effect.
58:46Music.
58:48Music.
58:50Music.
58:52Music.
58:54Music.
58:56Music.
58:58Music.