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  • it is quite amazing.

  • I mean, usually.

  • So this is a very big collaboration of people.

  • And usually word leaks out somewhere the sort of analogies thing that have not that long ago.

  • With the first results about gravitational waves on there, the world kind of nods and winks going on.

  • And if you knew the right people within, you could probably get a little bit of an inside track.

  • This there has been absolutely nothing.

  • They have really kept it completely under wraps.

  • The data they're gonna be presenting today was actually taken in 2017.

  • So they've been analyzing for the last couple of years is kind of the nature of this data.

  • It is incredibly complex.

  • So actually getting it to a point where you go from the raw data to something that looks like an impressive in image is a lot of work on them, so that would have taken most of the last couple of years.

  • But at this point, they must know that they've got something good.

  • So this thing called the event horizon is kind of that point of no return.

  • It's the point where you can not even light can no longer escape from from the region around a black hole.

  • The region we would hope to see today is a bit bigger than that.

  • It's probably about two or three times that event horizon size.

  • Um, really, Because well, it's because the distorting effects are so strong because what we're actually going to see a sort of light from around the black hole radio wave light and that radio wave light is originating a little bit further away.

  • And also you got this massive object in the case of the one in the middle of Milky Way.

  • It's about four million times the mass of the sun, which really means that the powers of light you think about like traveling in straight lines.

  • But because the gravitational field is so intense on the space, time is so curved the light actually travels in very bent.

  • Paul's technique they're using is the tinkle very long baseline interferometry, So the object that they're trying to resolve the size of the event horizon is about 30 times the radius of the sun.

  • So it's absolutely tiny at the distance of the galactic center, and the region that they're trying to say is a bit bigger than that, but it's still absolutely tiny thing analogy that's being drawn is it's like trying to take a picture off a golf ball on the moon.

  • Okay, so the technique and the technique they using really involves making the diameter of the telescope bigger and bigger.

  • And so one thing you could do is instead of having a single telescope, we have multiple telescopes, and then, as you move them further and further apart, the sharpness of the image increases because of the ultimate sharpness is limited by the distance between your two most distant parts of your telescope.

  • In the technique, they're using their actually recording the data on different radio telescopes around the world.

  • So these enormous it's the diameter of the earth is the diamond of the telescope they're using.

  • But then the tricky part is then, having collected all that data, you then have to combine it all together, and that's the technique that they're using.

  • This thing called very long baseline interferometry, involves taking all that signal on.

  • Actually, it's so they collect so much data.

  • It's not something you can just transfer over the Internet.

  • They actually end up recording the data on hard drives, shipping the hard drives to a place where you can kind of correlate all that data together on combining the information from the telescopes to extract an image from it, so that the troubles everyone has in their mind the movie interstellar, right?

  • Because they had the most amazing graphics of what one of these supermassive black holes would look like on they were actually, you know, they had real physicists involved in it.

  • There was actually lots of serious general relativistic calculations went into making those those graphics for the movie cause the trouble is they could do that whatever resolution they wanted, real emitted by the resolution that we can achieve with the wavelengths that we have with the diameter of the Earth that we have, which really means that you're not going to see those incredibly pin sharp images.

  • The whole thing is gonna be a bit blurry, but hopefully it's going to be a blurry image of something really exciting on a blurry image of something really exciting is probably pretty exciting itself.

  • There was one other thing to mention, which is that there's another candidate out there.

  • They're actually observed two objects so they observed the object in the middle of the of the Milky Way, which is this black hole of about four million times the mass of the sun.

  • They also were looking at the black hole in the middle off a much bigger galaxy Messier 87 in the middle of the Virgo cluster, which is several 1000 times further away.

  • So actually, the the quality of the images will be several 1000 times poor up because you're trying to look at something further away, so everything's much smaller.

  • But the black hole in the middle of Messy 87 is several 1000 times bigger than the black hole in the middle of the Milky Way, and it turns out that event horizon size scales with the mass of the black hole.

  • So if you've got a black hole, which is a couple of 1000 times bigger in mess than its, its event horizon will be a couple of 1000 times bigger as well.

  • So whole thing scares up in size.

  • So it turns out the ultimate sharpness is the image that they will get from the black hole in the middle of Messy 87 is about the same as from the Milky Way.

  • Andi.

  • It's a bit of a toss up.

  • Which one's gonna make the night of pictures?

  • I think my bet is still on the Milky Way because it's actually works that when you do the calculations, it works out.

  • You end up with slightly sharper images for the Milky Way, but there's not much in it.

  • Yeah, this is probably looking Alexi, and this is the first up in trouble.

  • These images are not sufficient.

  • If you want to know what the black hole looks.

  • Fine.

  • Eso from our chatting before the press conference.

  • I was wrong and I was right.

  • I was wrong because I picked the wrong black hole.

  • I said They're looking at to the one in the middle of the Milky Way and the one in Messier 87 I thought they'd be more likely to find something about how one.

  • But it turns out that this is the one that got the result from today's announcement was pretty special, actually, because I've been working on Black hold myself for 20 years.

  • I did.

  • My PhD in black holes have been working on that ever since.

  • A lot of former mother.

  • So today feels like quite profound day.

  • And to make it even more special was watching the press release downstairs with my six year old son, Andi.

  • Hey had this toy black hole with him and he was sitting there comparing it with the thing on the screen.

  • And it does look more or less as we were talking about before that There is this kind of ring of fire effect that are more particularly, you're kind of not seeing any light from the middle there.

  • And it really is just out of this effect that the light is being so bent by this black hole somewhere in the middle there that the light you're seeing kind of coming out around the size is actually being admitted around the back of the black hole on being bent.

  • Right rounds have been bent by 90 degrees and more to head towards us and into our line of sight.

  • And that really is sort of the definition of strong gravity, right?

  • I'm coming late to the party.

  • Here is currently to 40 Nottingham Time, and it's been half a hour since the results were released.

  • In that time, I've been interviewing perspective Undergraduates, Um, and I actually made them sit down and watch the press release up until the point where we saw the image of the black hole.

  • And then I I thought, we better get on with the business of the interviews, he said.

  • Yes, it looks looks like our toy black hole.

  • But the real black hole doesn't have eyes, and the real black hole isn't this cute.

  • Cuddly is this work, And he said, My toy black hole doesn't have the ring of fire around it.

  • We know that light gets bent by gravity.

  • It has been known for, actually almost exactly 100 years.

  • The first measurements of this effect were made almost exactly 100 years ago, when they were looking at what happens during a total eclipse of the sun, where stalls near the sun.

  • The position of the stars shifts a little bit just because the light from those stars is being bent tiny, bit by the but by the gravity of the sun.

  • So we've known about this affecting kind of that weak gravity limits that things like can get bent a tiny bit by something as massive as the sun Now we're talking about, like getting bent through 90 degrees and more on now.

  • You're talking about really, really strong gravitational field, so that gets us very much into the Einstein end of general relativity.

  • If you were just presented with a picture like that and say What's going on, you could come up with many explanations as to what it waas that that there was a cosmic donor out there in space.

  • Or there's a sphere and you're seeing the ages of a sphere or whatever.

  • You know, there are lots of ways you could explain.

  • There are many things in space that look like rings, but the thing is here, they said, OK, so we think that general relativity is right, and we think there's a massive black hole in the middle of these galaxy, and we think that it's got a lot of this sort of radio admitting material around it.

  • What would we expect to see if those things were the truth?

  • And then they predicted, this is what you want to see you pretty much on.

  • Then you go out and take the picture, and there it is.

  • And then so in some sense, that's the best proof the reverie is, is when you actually put it something before you go and see it on DSO.

  • I think in that sense, it's probably used the best evidence there's ever bean for a supermassive black hole in the middle of a galaxy.

  • Again, there are lots of ways that you can get those kind of a symmetries.

  • The most likely, I think, is that what's actually happening is that the material is rotating.

  • It's no.

  • It is not just sort of uniformly spread around there.

  • It's actually spinning around because we know further out.

  • That's a disk of material which is spinning around.

  • So the stuff we're staying close to the black hole.

  • It's probably in a rather turbulent, messy way.

  • Still rotating around on what happens is the bit that's coming towards you gets a big boost in energy thing called the Doppler Effect and in light, the way one of the ways that manifest itself is that the light gets a lot brighter.

  • That's a lot more energy in it.

  • Where's the stuff is going away from you, you see, it'll ah, lower energy and so you basically see it is fainter and so I think that asymmetry we're seeing there is just to do with the rotation of material around the black hole.

  • There was a lot of structure there as well that it looks like there's something that points out this way as well.

  • I'm kind of intrigued.

  • By and again, one of the things that might be expected, as you might expect jets of material to be flying out of the black hole on the material would probably be rotating around those jets of material.

  • So it sort of fits together, but I gain.

  • That's kind of down near the limits of what you can actually see on an image like that.

  • But this really this is just my very first reaction to it s So I am really looking forward to reading about the science has come out of this about whether structures that I'm seeing in the background here, a riel on what they mean, Um, and just how these predictions match up not just on a qualitative level, but on a quantitative level to the data that's actually been gathered.

  • I mean, the other thing that you sort of have to take your hats off to the people involved in this experiment is you have to bear in mind the technique they're using v o B I.

  • It's not just like taking a picture with the camera.

  • You've got to take all these data from all these different radio telescopes.

  • Combine them all together and from that, So basically, you take sort of every pair of radio telescopes and you get a bit of information from the sort of the phase delay.

  • The difference in the signal between each pair and each of those gives you a little bit of a picture.

  • But actually you don't have the whole picture.

  • And it is.

  • It's essentially because, you know, if you got a regular camera, you're kind of got your lens or your mirror.

  • If it's a telescope, is sort of filling the entire Apertura.

  • In this case, you've just got a few dishes sort of scattered within your aperture.

  • That means there's a lot of missing information, which means that you then have to kind of reconstruct that missing information, and they're actually there isn't generally a unique solution to this.

  • So there is a little bit of kind of prejudice that goes into this that says, because you could.

  • You know, there are many different images you could reconstruct from those data.

  • Most of them look completely ridiculous.

  • And so you can sort of throw them out on the basis that they look on physical, that they just very noisy or they just that don't match what you'd expect from a real astronomical object on.

  • So there's sort of a lot of processing that has to go into turning this data into an image.

  • Now, what's gonna happen over time is the more and more dishes get added to this network of telescopes, so you have more and more pairs of telescopes, which gives you more arm or information.

  • So as time goes on, they're gonna be repeating these experiments with Maura Maura information so the images will get better and better, and they'll be less of that kind of interpolation of figuring out the missing data just because it'll be less missing data.

  • But for the moment, that's a lot of work that has to go into turning the rule data into an image like this.

  • And so that's, I think, fundamentally, the reason why it's taken a ll the time from when they took the data two years ago to now to actually produce an image like this from the data they collected.

  • So there's talk about putting radio telescopes into space because remember what dictates the sharpness of the images, how far apart, your most distant party, a telescope?

  • Or if you could put your telescopes into orbit?

  • If you could put one of them on the moon that he could put them all into orbit around the sun, then in principle, you could make longer and longer.

  • Baselines.

  • There's not a lot to this picture, is there?

  • Really?

  • It's like, you know, it's a ring with a hole in the middle, but actually, I think that's absolutely astounding.

  • How amazing is that that, you know, millions of light years away?

  • You can actually see a black hole in another galaxy down to the scale of the black hole.

  • Remember the black region in the middle?

  • It's about three times the ultimate size of the black hole itself.

  • So the black hole itself is actually not much smaller than this.

  • We really are getting right down into that strong gravity regime right next to the event horizon of a black hole.

  • Actually, I said, it exceeded my expectations with simulations of what this might look like.

  • And they look more or less exactly like this.

  • But I thought, with scattering of light and instrumental effects and noise, you know they'll be lucky to get it to get the prediction as accurately as that.

  • But it looks bang on.

  • So it's pretty, pretty special.

  • Say, we're seeing this radio synchrotron radiation from the immediate vicinity of a black hole.

  • You can see the black hole itself shadowing the light so you can see its influence.

  • It's pretty special.

  • Yeah, that people be analyzing these data for years to come?

  • I think so.

  • I feel like I just feel like a real breakthrough.

  • Yeah, well, I mean, remember, you're looking at radio waves here, so you could actually make this any color you want it to be.

  • Fundamentally, they clearly just pick something which look nice.

  • You could probably would have done it in black and white or because we're these are what you're really looking at here.

  • A millimetre waves, no optical light it all.

  • So, yes, there is a certain matter of aesthetics as to what color you end up reproducing these images and it makes a big difference.

  • That's the other interesting thing that you know.

  • NASA employees, graphic designers who know what looks really nice because you do have that degree of freedom because it is all about how you present the data on you know it's not.

  • There's no dishonesty here in that.

  • The reason the right color causes to say these radio waves.

  • Radio waves aren't either blue or green their radio waves.

  • So actually, you really can pick whatever color looks nicest if the galaxy's the size of a football.

  • The supermassive black hole in the nucleus is the size of a hydrogen atom, so absolutely tiny but the energy they can produces and bacon more than enough to blow the galaxy the bits many times over.

  • So they understanding the link between these supermassive black holes, like the one we found that there was today on the broader Galaxies that they're embedded in.

  • I think that's a really key issue for me personally.

  • It's nearing our work on how to Galaxies form.

  • How did they switch off forming stars, but called may play a role and now we know that the really old black holes in there so We knew that before, but we've got an actual image of one.

  • For the first time.

  • There's been loads of evidence for black holes, but no actual image.

  • Take a picture of one, so it's very special.

  • We've made quite a few videos about black holes over the years.

  • I'm gonna put a link in the video description and here on the screen also our astronomy channel, Deep Sky videos.

  • We've got video all about M 87 already on there.

  • So if you want to find out more about 87 again links on the screen video description.

it is quite amazing.

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THAT ブラックホールの絵 ⚫ - 六十のシンボル (THAT Black Hole picture ⚫ - Sixty Symbols)

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    林宜悉 に公開 2021 年 01 月 14 日
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