Making a movie of a black hole

4:01over and over and create a movie >> of a black hole of the accretion disc revolving around a black hole and all of the weird physics that happens around that black hole. Right? So now you can start testing the theories and it's it's such a cool thing that we are able to do because of all the technology that we have. So if you start from the beginning right the most of the photos that you see of the black hole like that cat meme that is of M87 which is this galaxy 55 million lighty years away. It was first discovered in 1781 as part of the Messier catalog. Charles Messier was a French comet astronomer and he was basically like trying to hunt for

4:43comets. That was his big passion. And when you hunt for comets what do you do? You basically point the telescope at the sky and you look for fuzzy objects. But those fuzzy objects have to move. So in order to distinguish the ones that are moving from the ones that are not, he created a catalog of all the all the things that he should be ignoring. And that became the Messier catalog, which is now much more important than all of his comet. >> That's so >> research. You know, he was trying to basically find comets. And he he made a list of stuff to ignore. like you know when you're like coding or something and it's like ignore this flag, ignore this flag. That that that was him with the

5:23entire night sky. He created this giant catalog and turns out he cataloged I think something like on the order of hundreds if not maybe a thousand objects that are now like nebula galaxies other things that are close to the Milky Way and close to close to the sun. This is like a classic story in science which is kind of like our Hubble story with the deep field we did a few episodes ago which is let's point this at a >> a space of nothing >> and see what happens and and everyone's like what and it became one of the most important things ever and it's like sometimes you know >> you stumble upon discoveries and just being serendipitous is really important in the process because it it it does

6:04still again in this case it's a little bit annoying because he's like I I cared about this thing and I'm known for this other thing. But it's like you still did the work. >> No. And and I I don't think he would mind if he was alive today that all of these objects have the prefix M and then and then and then the object right in front like right everybody knows M87 in >> astrophysics because this is the closest large super massive active galactic nuclei to the Milky Way. It's only 55 million lighty years away which is actually quite close. Like the Andromeda galaxy is 2 million lighty years away. So this is only like what 20 to 30 times as distant as the Andromeda galaxy. So it's really in our local, you know,

6:45we're talking about tens of millions. The universe is tens of billions, right? So this is this is very local to us. It's it's in the constellation Virgo. And um you know to your point it's it's one of those things where cataloging negative results was actually a good thing in science everybody if you want to publish in science and nature and cell you have to come up with results and positive results. It's like oh I did an experiment I had a hypothesis the hypothesis worked here. He was just cataloging like negative things because he thought these are the stuff that I want to ignore. And it turns out the negative results in this particular scientific endeavor was the most

7:26important thing that he did in his life. Right. Kind of cool, >> right? >> Um so anyways, it turns out to be um one of the largest galaxies in our neighborhood and um it's the most studied super massive black hole in history. [snorts] If you go back to that photo, actually photo number two. >> Yes, photo number two. Notice you've got the it's an elliptical galaxy, so it doesn't have a lot of structure, which means it's full of old stars and it's massive. Okay? It's not a spiral galaxy in the sense that the Milky Way or the Andromeda galaxy is. And also, there's this giant jet. It's it's like a it's like a hose coming out of that center, right? >> Mhm.

8:07When people saw that using the radio astronomy that was built up after World War II, people were like, "That's really weird." Because one, you can actually measure the speed of that jet and it's very, very close to the speed of light. At some point, people were actually saying super luminous. It was higher than the speed of light. Turns out it was like it's not an error, but there's like some weird physics going on that like makes it seem like the stuff is moving faster than the speed of light, but really it's like kind of a group velocity type thing. Um the the actual stuff is not actually moving faster than the speed of light, but maybe some phenomenon is. Um

8:48when when people saw that, they were like, there's got to be something really energetic at the center of that thing that is causing a giant jet to form. That's like many light years in size. >> What what is creating the the inciting what is creating the force that is enabling us to image this particular situation? >> Yeah. Like if you've got a hose, right, and and the hose produces a jet that's light years long, the the hose has to be insanely strong. And so that's where we get the idea of active galactic nuclei. the idea that there could be a super massive black hole at the center that is creating so much energy from accreting

9:31matter into the black hole that that heat and that magnetic field and that plasma is shooting out a bunch of material at this incredibly high speed. So this [clears throat] is the first sort of indication that yes black holes are real and perhaps um we can study it in a really really precise way. Okay. Um then in 2019 we got two images these amazing images that popped up all over social media took over the entire globe. On the left is the black hole of M87. The center is probably where the event horizon is. Okay. That's where >> the the dark spot in the middle.

10:11>> Yeah. That's that's really what the black hole is. But obviously a black hole is somewhere is is a region of space where nothing can escape, not even light. So if light can't escape, how do you image it? Well, what you're really imaging is the accretion disc around the black hole. And I want to take a quick moment for our audio listeners. You know, many of you will have seen this image. It looks like a glazed donut, right? You have that orange glow, the black center, and and it was very big in this time period. But that that is the image we're looking at two, but that is one of the two that we're looking at. And then you'll get to the second here. >> Exactly. Okay. And and so the one on the left is the one at M87. That's 55

10:53million lighty years away. >> Okay. >> The one on the right >> and and you can see the size of that relative to the one on the left. Right. The the the one on the right you can see the inset. It it it would fit very neatly inside the black hole inside the event horizon of M87. The one on the right is our puny little black hole of the Milky Way. >> Ah okay. Yeah. >> Okay. >> Yes. And it's it's quite amazing that the M87 black hole is so much bigger than the Milky Way, >> right? We're it's probably in the way these images are scaled, we would say maybe it's >> two and a half to three and a half

11:33times. >> Yeah. >> Scale-wise, >> I will say that this the the R is is I think it's uh is it Sagittarius A? >> Sagittarius A. >> Sagittarius A. Kind of looks like a bagel. Yeah. >> A little more bagel shaped. >> Yeah. Compared to the donut shape. [laughter] Yeah. Yeah. Yeah. And and that's probably um >> it's probably a feature of the fact that M87 is so big >> that like the accretion disc is like more uniform and it's like farther away so you're not getting the nitty-gritty details. Um now the relative size of these photos you can see that like you know in terms of the relative size they look about the same. >> Yeah. Yeah. Yeah. Yeah, that's because in the sky, relative size-wise, they

12:15look about the same. It's just that the Milky Way black hole, Sagittarius a star, by the way, it's not Sagittarius A. The star means that we're talking about the the black hole. That's that's always like that's all the M87, you see the M87 star. So, that means we're talking about the black hole. >> And when we say star, we we mean asterisk. >> Asterisk. Yeah. Yeah. But in in colloquial language, >> 100%. Just for people who might be viewing it, that's what we're referring to as the asterisk. >> Exactly. Yeah. So whenever you see like that, that means we're talking about the black hole at the at the center of the galaxy. And the two are about the same size in the sky. So this is how how big they would look if we could like zoom in zoom in zoom in. >> It's just that the Milky Way, even though it's so much smaller, yes, >> it's so much closer to us. It's only

12:56100,000 lighty years, right? Compared to the 55 million lightyear. So even though the M87 is actually way bigger, it would it could fit the entire Milky Way black hole inside because it's so far away. The size of it looks about the same. So now that brings me to my second point.