WEBVTT - Flares from Infinity: Sagittarius A* Part 1 0:00:02.560 --> 0:00:06.680 Further out in the dark, we found alien life. There 0:00:06.680 --> 0:00:09.920 were mats of corn colored slime glowing in the deep 0:00:10.320 --> 0:00:13.039 as they fed on jets of sulfur bubbling up from 0:00:13.039 --> 0:00:16.960 the mud at the bottom of a flooded crater. White 0:00:17.040 --> 0:00:20.520 ticks that tunneled through the ice, growing in spindles above 0:00:20.560 --> 0:00:24.680 the salt flats, the ruins of empty cities covered in 0:00:24.800 --> 0:00:29.360 mosslike growth on quiet planets. But as we journeyed further 0:00:29.440 --> 0:00:34.640 in into the hub, into the permanent light, everything was dead. 0:00:35.640 --> 0:00:39.519 What could live here? The stars hurtled past one another, 0:00:39.960 --> 0:00:43.040 dragging their doomed clouds of matter with them to collide 0:00:43.080 --> 0:00:47.040 like weather fronts. The radiation is a hot bath, the 0:00:47.120 --> 0:00:51.880 killer surf rocking in from all around. The night swarms 0:00:51.920 --> 0:00:56.840 with starlight. But our journey goes on because the Center calls, 0:00:57.680 --> 0:01:05.399 We're going to the bottom of the galaxy. Welcome stuff 0:01:05.400 --> 0:01:07.440 to Blow your Mind. A production of I Heart Radios 0:01:07.440 --> 0:01:15.240 How Stuff Works. Hey you, welcome to Stuff to blow 0:01:15.280 --> 0:01:18.440 your Mind. My name is Robert Lamb and I'm Joe McCormick. 0:01:18.480 --> 0:01:22.120 In Today we're coming back with some space themed I 0:01:22.200 --> 0:01:23.800 was about to say the word content. I'm not going 0:01:23.840 --> 0:01:26.880 to say the word content. I'm gonna say space themed stuff. 0:01:26.920 --> 0:01:30.440 That's an old favorite how stuff works fans. How about 0:01:30.440 --> 0:01:33.640 a space material. There's a lot of discussion of material 0:01:33.840 --> 0:01:37.760 and particles this episode in the one that follows it, 0:01:38.080 --> 0:01:40.639 because of course we're going to be talking about black 0:01:40.640 --> 0:01:43.039 holes once again. Yeah. Now, we did I think a 0:01:43.160 --> 0:01:45.800 three part series on black holes. It was sometime last year, 0:01:45.880 --> 0:01:48.560 maybe a year and a half ago, but we wanted 0:01:48.600 --> 0:01:52.000 to revisit the topic to talk about a specific case 0:01:52.120 --> 0:01:55.720 of very interesting black hole that we didn't get deep 0:01:55.760 --> 0:01:58.720 into in our last four That's right, So I do 0:01:58.760 --> 0:02:01.160 want to just so so really you can go about 0:02:01.160 --> 0:02:03.920 this two ways. Uh, you could treat this is part 0:02:04.000 --> 0:02:07.080 four and part five. Uh, and you know, go listen 0:02:07.160 --> 0:02:09.799 to the three previous black Hole episodes again. But I 0:02:09.800 --> 0:02:12.400 don't think it's entirely necessary. I think you can. You 0:02:12.440 --> 0:02:14.359 can come in and listen to these is just simply 0:02:14.440 --> 0:02:16.880 part one in part two of a look at a 0:02:16.960 --> 0:02:21.880 very particular type of black hole, a super massive black hole, right, 0:02:21.919 --> 0:02:24.200 and we'll do refreshers on the basics. So it's not 0:02:24.240 --> 0:02:26.680 like you've you've got to have done your homework here, right, 0:02:26.760 --> 0:02:29.800 you have to have seen either event Horizon or Disney's 0:02:29.840 --> 0:02:32.480 The black Hole. Otherwise you have no frame of reference. 0:02:32.600 --> 0:02:35.320 That's the starting homework. That's like the summer reading before 0:02:35.400 --> 0:02:37.840 you start our podcast in the ball well, you know, 0:02:37.960 --> 0:02:39.919 I mean the weird thing is that, you know, those 0:02:39.960 --> 0:02:43.320 are two films that I think are in some cases 0:02:43.320 --> 0:02:46.600 people's first introduction to the concept of a black hole. 0:02:46.960 --> 0:02:49.040 And granted, those are two films that, each in their 0:02:49.040 --> 0:02:52.440 own way are loaded with errors and problems and misinformation. 0:02:53.360 --> 0:02:55.960 And yet Fantasy black Hole and the Fantasy black Holes. 0:02:56.000 --> 0:02:58.640 But you know, a fantasy black hole is I think 0:02:59.200 --> 0:03:02.120 a good starting place in many respects. You know, it 0:03:02.160 --> 0:03:06.000 gives you a fantastic notion, sometimes an you know, an 0:03:06.040 --> 0:03:10.040 action pack very uh you know, terrestrial model of what 0:03:10.080 --> 0:03:12.880 a black hole is. And it's not a bad place 0:03:12.919 --> 0:03:17.600 to then begin and then build scientifically on the concept. 0:03:18.240 --> 0:03:21.080 There is a kernel of truth in the suggestion of 0:03:21.120 --> 0:03:23.520 the Fantasy black hole, which is that while we know 0:03:23.639 --> 0:03:26.079 more about black holes than we ever have before, and 0:03:26.440 --> 0:03:28.040 this year, for the very first time, we think we 0:03:28.160 --> 0:03:30.400 got you know, basically a direct image of a black 0:03:30.400 --> 0:03:33.079 hole to whatever extent that's possible. And talk more about 0:03:33.120 --> 0:03:37.000 the specifics of that later on, But but yeah, while 0:03:37.080 --> 0:03:39.440 we still, while we know more than we ever have, 0:03:39.640 --> 0:03:43.120 black holes still contain a lot of mysteries. They contain 0:03:43.200 --> 0:03:46.200 some edge cases for our theories of physics where what 0:03:46.280 --> 0:03:48.960 we know ceases to make sense. And so there's still 0:03:48.960 --> 0:03:51.840 a lot of lingering questions, a lot of tantalizing mysteries. 0:03:52.080 --> 0:03:55.040 But before we get to the tantalizing mysteries and the 0:03:55.120 --> 0:03:58.720 lingering questions, I want to talk about a a nerdy 0:03:58.760 --> 0:04:04.280 engineer born in Oklahoma whose middle name is Gooth. I mean, 0:04:04.360 --> 0:04:07.560 that's a that's an excellent nerd middle name. Okay, So 0:04:07.560 --> 0:04:10.600 I'm going to talk about Carl Gooth Jansky. He was 0:04:10.640 --> 0:04:13.960 born in Norman, Oklahoma, in nineteen o five, one of 0:04:14.040 --> 0:04:18.320 six children, and his family and Jansky's dad, Cyril, was 0:04:18.440 --> 0:04:22.640 an electrical engineering professor. It's a little Carl Jansky. When 0:04:22.680 --> 0:04:25.640 he grew up, he followed in his father's trajectory to 0:04:25.680 --> 0:04:28.480 study physics and engineering as well. So as a young man, 0:04:28.600 --> 0:04:31.839 Karl Jansky earned a degree in physics from the University 0:04:31.839 --> 0:04:34.640 of Wisconsin. I think he got his undergraduate degree but 0:04:34.680 --> 0:04:37.320 then failed to complete his masters. But then anyway, he 0:04:37.360 --> 0:04:39.880 went on to get hired by a company he was 0:04:39.960 --> 0:04:43.080 hired for a position as a radio engineer with Bell 0:04:43.240 --> 0:04:46.240 Telephone Laboratories in ninety eight, and this would have been 0:04:46.279 --> 0:04:49.360 when radio engineering was something fairly new, So at this 0:04:49.480 --> 0:04:53.000 time in the late nineteen twenties, Bell Labs was interested 0:04:53.120 --> 0:04:58.240 in creating a system for a wireless radio based telephone 0:04:58.279 --> 0:05:01.720 service that would allow ins atlantic phone calls and let's 0:05:01.720 --> 0:05:04.560 just say you needed to call across the Atlantic Ocean 0:05:04.760 --> 0:05:08.479 to order a bagat or something. These radio based phone 0:05:08.480 --> 0:05:10.640 calls that Bell Labs wanted to do would have been 0:05:10.640 --> 0:05:14.159 in the short wave frequency range, meaning wavelengths of about 0:05:14.160 --> 0:05:17.480 ten to twenty meters, and Jansky was given the job 0:05:17.760 --> 0:05:22.000 of hunting down any potential sources of radio interference that 0:05:22.040 --> 0:05:25.719 would cause static on the calls. So Jansky built a 0:05:25.880 --> 0:05:30.479 giant receiver antenna to detect signals at a wavelength of 0:05:30.560 --> 0:05:34.839 fourteen point five meters. And this was a directional antenna, 0:05:34.960 --> 0:05:37.159 and that meant that it could be moved around to 0:05:37.360 --> 0:05:41.719 identify the origin vector of any particular signal. Right, so 0:05:41.720 --> 0:05:45.240 it's not receiving signals from every direction the same you 0:05:45.360 --> 0:05:47.520 aim it in the direction that you want to pick 0:05:47.600 --> 0:05:50.280 up the signal from. And it was mounted on a 0:05:50.320 --> 0:05:54.640 giant rotating platform outfitted with motorized wheels. Actually there were 0:05:54.640 --> 0:05:57.400 the wheels from a model T and it could be 0:05:57.440 --> 0:05:59.719 aimed in any direction to root out the sources of 0:06:00.000 --> 0:06:02.840 attic or other interference that they were looking for. Some 0:06:02.880 --> 0:06:05.720 people called this Jantski's Merry go Round. I've got a 0:06:05.720 --> 0:06:08.719 photo of it here for you, Robert. Yeah, at first glance, 0:06:08.800 --> 0:06:13.200 it looks not unlike a giant biplane of some kind, 0:06:13.320 --> 0:06:15.760 you know. Oh yeah, with the struts on the wings, 0:06:16.160 --> 0:06:20.159 it looks like the world's most dangerous gymnastics equipment. It's 0:06:20.200 --> 0:06:22.880 just broken shins all around. Yeah, it looks a little 0:06:22.880 --> 0:06:27.000 bit like scaffolding or uh, the system of goals and 0:06:27.160 --> 0:06:31.200 some sort of Susian sport. But in the middle, of course, 0:06:31.200 --> 0:06:33.200 it's got wheels, and it's got a little track that 0:06:33.279 --> 0:06:35.919 the wheels roll around on so that you can aim 0:06:35.920 --> 0:06:38.920 it to to calibrate where the source of the interference 0:06:39.000 --> 0:06:41.720 is coming from. So, first of all, he discovered the 0:06:41.760 --> 0:06:46.239 main source of terrestrial interference on this radio frequency range, 0:06:46.520 --> 0:06:50.000 which was electrical storms. So if there's a thunderstorm nearby 0:06:50.200 --> 0:06:52.839 that could generate static. You can even get some static 0:06:52.880 --> 0:06:57.840 from distant thunderstorms. But Jansky also discovered a source of 0:06:57.880 --> 0:07:02.040 noise in this frequency range that seemed unrelated to thunderstorms, 0:07:02.279 --> 0:07:07.440 quote a steady hiss type static of unknown origin. This 0:07:07.520 --> 0:07:10.360 signal would go through a cycle once a day, peaking 0:07:10.400 --> 0:07:13.840 in intensity and then fading roughly every twenty four hours, 0:07:13.840 --> 0:07:17.760 but not exactly every twenty four hours, just slightly, just 0:07:17.840 --> 0:07:21.120 slightly less than twenty four hours. Now, at first, you know, 0:07:21.160 --> 0:07:24.680 what would you conclude if something was emitting radiation powerful 0:07:24.800 --> 0:07:28.080 enough to cause terrestrial radio interference in a cycle that 0:07:28.200 --> 0:07:31.040 lasted about one day? What would you think it probably was? 0:07:31.160 --> 0:07:33.600 But that that brings one's attention to just like the 0:07:33.600 --> 0:07:37.040 immediate neighborhood of the Solar system, something to do with 0:07:37.120 --> 0:07:40.360 the Earth's position relative to the Sun. Yeah, exactly. You 0:07:40.440 --> 0:07:43.760 think it's probably the Sun, right, But Jansky chased the 0:07:43.800 --> 0:07:46.080 signal and it turned out it wasn't the Sun because 0:07:46.120 --> 0:07:48.800 he kept following it for several months, and while the 0:07:48.840 --> 0:07:51.440 signal at some point, I think when he was originally 0:07:51.560 --> 0:07:54.000 chasing it was kind of near the Sun, it shifted 0:07:54.080 --> 0:07:57.320 over time and moved away. And so after months of 0:07:57.440 --> 0:08:01.080 using his radio source finding techniques and teen thirty two 0:08:01.480 --> 0:08:03.600 he discovered or I think it was thirty one or 0:08:03.640 --> 0:08:06.640 thirty two. He discovered that the origin of this anomalous 0:08:06.720 --> 0:08:11.840 static hiss was coming from deep space, and he narrowed 0:08:11.840 --> 0:08:17.280 it down to an origin point roughly in the constellation Sagittarius. 0:08:17.440 --> 0:08:22.240 Now Sagittarius is named after a a centaur archer. In 0:08:22.400 --> 0:08:26.520 Greek mythology, it's associated with the centaur uh An. Ancient 0:08:26.560 --> 0:08:31.320 Mesopotamian astrology, the constellation Sagittarius was associated with the deity 0:08:31.440 --> 0:08:34.640 near gal a creature of fire and the desert and 0:08:34.720 --> 0:08:38.800 war and disease, kind of a a creepy demon type figure. 0:08:39.080 --> 0:08:42.160 In Greek and Roman astrology, the constellation was most often 0:08:42.200 --> 0:08:45.560 associated with the image of a centaur drawing a bow. 0:08:45.840 --> 0:08:49.280 So it's like this super accurate centaur archer who always 0:08:49.360 --> 0:08:53.600 hits his mark. Yeah, that centaur's that name is Chion, 0:08:54.320 --> 0:08:58.400 mentor of the Greek hero Achilles. Alright, I'd rather like 0:08:58.480 --> 0:09:01.280 the idea of of Achilles is the sort of mythical 0:09:01.400 --> 0:09:04.480 killing machine having been you know, the student of of 0:09:05.080 --> 0:09:07.200 of Well, I don't want to spoil it, but some 0:09:07.280 --> 0:09:10.680 sort of cosmic anomaly, like he was getting messages into 0:09:10.720 --> 0:09:14.480 his brain from space. Yeah, this was the static kiss 0:09:14.520 --> 0:09:16.600 talking to Achilles. Yeah, I mean, well, what is it 0:09:16.640 --> 0:09:18.880 to be, you know, to hear the voice of the gods, 0:09:18.960 --> 0:09:23.040 but to be, you know, an antenna receiving signals from beyond, 0:09:23.360 --> 0:09:25.760 or to get your brain hit by a cosmic ray. 0:09:26.360 --> 0:09:31.439 But anyway, like any constellation, Sagittarius, Sagittarius is not a 0:09:31.800 --> 0:09:35.240 thing up there. This is something that I often fall 0:09:35.280 --> 0:09:39.080 into the trap of thinking of constellations as like objects 0:09:39.160 --> 0:09:42.480 that exist in themselves. But of course a constellation is 0:09:42.520 --> 0:09:45.240 a number of stars that appear in a certain arrangement 0:09:45.360 --> 0:09:48.440 from our perspective here on Earth. It's not like those 0:09:48.480 --> 0:09:52.079 stars have a natural association with each other, right, It's 0:09:52.080 --> 0:09:53.880 just a yeah, it all has to do with our perspective. 0:09:53.920 --> 0:09:56.240 And then it just is a shorthand way of identifying 0:09:56.800 --> 0:10:01.040 different different portions of the night sky. They're not objects 0:10:01.040 --> 0:10:03.440 in the sky anymore than like the figure of a 0:10:03.480 --> 0:10:06.760 shadowy goblin hand cast on your window at night by 0:10:06.800 --> 0:10:09.959 a tree limb against the moonlight is an object. It's 0:10:10.000 --> 0:10:12.920 feature of your perspective where the lights coming from, where 0:10:12.920 --> 0:10:16.480 you're looking from. But an important thing about Sagittarius from 0:10:16.480 --> 0:10:20.120 our perspective is that this constellation just happens to be 0:10:20.240 --> 0:10:24.559 generally the direction of the center of the Milky Way galaxy, 0:10:24.800 --> 0:10:27.720 our galaxy, the one we live in. And this was 0:10:27.760 --> 0:10:32.120 what Jansky had discovered, an extraterrestrial radio source coming not 0:10:32.280 --> 0:10:36.040 just from space, but from the core of the Milky Way. 0:10:36.280 --> 0:10:38.480 Then they get you're prickling a little bit, Yeah, like 0:10:38.600 --> 0:10:42.480 something something major is happening there, something that we can detect. Right. 0:10:42.520 --> 0:10:46.000 So Jansky authored a handful of scientific papers on this finding, 0:10:46.040 --> 0:10:50.920 including a paper called Electrical Disturbances Apparently of Extraterrestrial origin, 0:10:50.960 --> 0:10:54.160 which he presented in nineteen thirty three to a conference 0:10:54.160 --> 0:10:58.360 in Washington of the International Scientific Radio Union. And this 0:10:58.480 --> 0:11:00.840 led to media coverage, including an article in The New 0:11:00.920 --> 0:11:03.360 York Times from nineteen thirty three, which you can still 0:11:03.400 --> 0:11:05.840 read online if you got a log in with your subscription. 0:11:05.880 --> 0:11:07.800 I looked it up and I read it. Can you 0:11:07.960 --> 0:11:12.120 guess what the reporters asked to Jansky? Can you just guess? Um? 0:11:12.200 --> 0:11:15.000 You probably asked, are their little green men? Of course, 0:11:15.480 --> 0:11:18.320 the concluding paragraph of the article is there is no 0:11:18.400 --> 0:11:21.280 indication of any kind. Mr Jansky replied to a question 0:11:21.480 --> 0:11:25.520 that these galactic radio waves constitute some kind of interstellar signaling, 0:11:26.000 --> 0:11:27.760 or that they are the result of some form of 0:11:27.840 --> 0:11:32.680 intelligence striving for intragalactic communication. I'm glad they cleared that 0:11:32.760 --> 0:11:35.320 up because they specify in the article that was a 0:11:35.400 --> 0:11:39.080 steady hiss of random radio static, which seems like a 0:11:39.120 --> 0:11:42.319 really bad type of radio signal to use for interstellar 0:11:42.360 --> 0:11:45.880 communication would be like trying to communicate with somebody by 0:11:45.920 --> 0:11:50.280 handing them blank pieces of paper. Plus ninety three not 0:11:50.360 --> 0:11:53.719 a great time period to be visited by some sort 0:11:53.760 --> 0:11:56.920 of extraterrestrial civilization. I mean, not that today is you 0:11:56.920 --> 0:12:01.200 know that we've necessarily got things in working order, so 0:12:01.280 --> 0:12:04.640 that so that some distant civilization can judge us and 0:12:04.679 --> 0:12:07.040 decide if we should uh, you know, be left to 0:12:07.080 --> 0:12:10.199 function on our own or not. But thirty three was 0:12:10.240 --> 0:12:12.080 not a great year, no, not not one of the 0:12:12.120 --> 0:12:15.439 best periods. So so he's not saying it's aliens. He's 0:12:15.480 --> 0:12:18.000 definitely not saying it's aliens. He's saying it's pretty much 0:12:18.080 --> 0:12:23.240 undoubtedly physical, not organic. But what was it? Well? Jansky 0:12:23.280 --> 0:12:26.080 wanted to continue research on this deep radio source at 0:12:26.080 --> 0:12:28.040 the heart of the Milky Way, but Bell Labs was 0:12:28.160 --> 0:12:30.600 of course not interested in funding this kind of thing. 0:12:30.640 --> 0:12:33.320 In the nineteen thirties, early nineteen thirties. You know, this 0:12:33.400 --> 0:12:37.120 is the depression. They're they're they're not just looking to 0:12:37.120 --> 0:12:39.680 to profligately spend money on astronomy. It was enough for 0:12:39.720 --> 0:12:43.959 them to have the radio telephone interference issues solved, But 0:12:44.240 --> 0:12:47.800 in the following decades many astronomers actually picked up where 0:12:47.880 --> 0:12:51.280 Jansky had left off, and Jansky is now remembered as 0:12:51.360 --> 0:12:53.880 one of the pioneers of radio astronomy. I've seen it 0:12:53.920 --> 0:12:56.840 speculated somewhere that if he hadn't died early he died 0:12:56.840 --> 0:12:59.080 pretty young, that he may have received the Nobel Prize 0:12:59.120 --> 0:13:02.120 at some point later. But he he hasn't forgotten. In fact, 0:13:02.160 --> 0:13:05.960 I almost forgot this. The massive radio telescope array in 0:13:06.000 --> 0:13:08.520 New Mexico known as the Very Large Array, which I 0:13:08.640 --> 0:13:10.959 visited in person last year and have talked about on 0:13:11.000 --> 0:13:13.600 the show before. It's actually named in his honor. It 0:13:13.640 --> 0:13:15.720 almost gets forgotten because it's the v l A. But 0:13:15.800 --> 0:13:19.360 it's the Carl G. Jansky v l A. Oh okay, cool, Yeah, 0:13:19.360 --> 0:13:21.600 I didn't realize that either. And there's also a metric 0:13:21.679 --> 0:13:24.440 named after him. And there's a unit in radiophysics known 0:13:24.480 --> 0:13:26.960 as the Jansky I can't remember exactly what it is. 0:13:27.000 --> 0:13:32.319 It denotes something. But now astronomers have since then has 0:13:32.320 --> 0:13:34.560 spent a lot of time and energy trying to understand 0:13:34.640 --> 0:13:37.280 what is happening at the galactic center, at the core 0:13:37.320 --> 0:13:40.120 of our galaxy. And this is really difficult because we 0:13:40.200 --> 0:13:44.280 can't leave our galaxy to look down on it from above. Right. 0:13:44.480 --> 0:13:46.920 If you've ever seen an image of the Milky Way 0:13:46.960 --> 0:13:50.720 depicted in like a circular shape, this is just a guess, 0:13:50.720 --> 0:13:53.319 a guess of an illustrator. We can't look at our 0:13:53.320 --> 0:13:55.600 galaxy from outside it. We're in it. It would be 0:13:55.640 --> 0:13:58.360 like trying to look at a storm from above while 0:13:58.400 --> 0:14:00.559 the storm you're standing on the ground. The storm is 0:14:00.600 --> 0:14:02.760 going on all around you. The center of the Milky 0:14:02.800 --> 0:14:05.360 Way is especially hard for us to see into because 0:14:05.640 --> 0:14:07.840 this region at the center of the galaxy that the 0:14:07.880 --> 0:14:11.000 rest of the galaxy orbits around, is shrouded by dust, 0:14:11.200 --> 0:14:15.560 these thick clouds of dust that obscure its millions of 0:14:15.640 --> 0:14:18.760 stars from our point of view. I've seen numbers that 0:14:18.840 --> 0:14:22.720 suggests there are like twenty five magnitudes of optical extinction 0:14:22.880 --> 0:14:25.400 from this region due to dust. And that's why, even 0:14:25.440 --> 0:14:27.400 though the core of our galaxy is by far the 0:14:27.440 --> 0:14:29.880 brightest part of the galaxy, it's lit up with tons 0:14:29.880 --> 0:14:33.080 of stars. There's all this dust there that blots out 0:14:33.120 --> 0:14:36.360 the light and mutes that brightness from our point of view. 0:14:37.120 --> 0:14:41.160 But modern telescopes and equipment have given us other ways 0:14:41.240 --> 0:14:43.760 to peer through the dust into the center of the galaxy. 0:14:43.800 --> 0:14:48.440 For example, through infrared and other radio frequency detections, we 0:14:48.520 --> 0:14:52.360 can see what's shining from within. And today astronomers believe 0:14:52.400 --> 0:14:56.480 we have extremely compelling evidence that this radio source at 0:14:56.520 --> 0:15:00.440 the center of the galaxy uh Is is a regions 0:15:00.440 --> 0:15:06.200 surrounding a gigantic supermassive black hole. This compact radio source 0:15:06.280 --> 0:15:09.840 together is known as Sagittarius a star. And if you 0:15:09.920 --> 0:15:14.160 see this printed or you know, type, it is a 0:15:14.240 --> 0:15:19.280 Sagittarius a asterix. The asterix stands for star, right, Yeah, 0:15:19.320 --> 0:15:22.480 it's pronounced star. But it always, for the longest time, 0:15:22.520 --> 0:15:24.400 whenever I saw it, it it would confuse me because I'd 0:15:24.400 --> 0:15:26.400 see it then it looked like, Okay, I'm looking for 0:15:26.440 --> 0:15:31.640 the note and there's not one. Because in astronomy that 0:15:31.640 --> 0:15:34.720 that asterix denote star. And we'll get to the you know, 0:15:34.800 --> 0:15:36.560 the details on that in a bit. Yeah, it was 0:15:36.640 --> 0:15:40.000 named that way for a cheeky reason by an astronomer 0:15:40.480 --> 0:15:42.760 in the nineteen seventies. But maybe we should take a 0:15:42.760 --> 0:15:44.360 break and then when we come back, we can sort 0:15:44.400 --> 0:15:47.320 of do a refresher on black holes and get into 0:15:47.360 --> 0:15:52.520 the details of this supermassive black hole. Thank alright, we're back, 0:15:52.640 --> 0:15:54.320 all right. So, as we said before, we did a 0:15:54.360 --> 0:15:56.240 whole series on black holes about a year and a 0:15:56.280 --> 0:15:58.480 half ago. You can go listen to those if you want. 0:15:58.960 --> 0:16:01.200 They get way into the history of the discovery of 0:16:01.200 --> 0:16:03.720 black holes and all that, but we'll do a brief 0:16:03.720 --> 0:16:07.200 refresher here. One quote I really like comes from the 0:16:07.240 --> 0:16:10.800 physicist Supermanion Chandra Shekar, who is very important in the 0:16:10.800 --> 0:16:13.520 history of black hole research. Uh. And he wrote a 0:16:13.520 --> 0:16:16.320 book called The Mathematical Theory of black Holes, and in 0:16:16.360 --> 0:16:19.080 the prologue there's a part where he writes, quote, the 0:16:19.120 --> 0:16:23.520 black holes of nature are the most perfect macroscopic objects 0:16:23.520 --> 0:16:26.320 there are in the universe. The only elements in their 0:16:26.360 --> 0:16:30.360 construction are concepts of space and time. And this gets 0:16:30.360 --> 0:16:34.200 to some of the history we discussed in those previous episodes, 0:16:34.400 --> 0:16:37.920 being that, like, the black hole was the thing that 0:16:37.920 --> 0:16:41.280 that we saw in the math before we even began 0:16:41.400 --> 0:16:44.360 to like, you know, to to see through uh. You know, 0:16:44.480 --> 0:16:48.720 other astronomical means. Yeah, it existed in theory long before 0:16:48.840 --> 0:16:52.000 it had ever been detected directly. In fact, you could 0:16:52.000 --> 0:16:55.320 only argue probably that that you could well, I don't know. 0:16:55.360 --> 0:16:57.840 I guess it depends on what evidence people count. But 0:16:58.320 --> 0:17:02.040 there is evidence now that seems to be direct indications 0:17:02.040 --> 0:17:04.840 of black holes, but it's hard for reasons that we'll 0:17:04.840 --> 0:17:07.280 talk about in a minute, I guess, yeah, for for 0:17:07.400 --> 0:17:09.760 the longest black holes. So certainly if you pull out 0:17:09.840 --> 0:17:12.920 an older textbook, they're going to refer to black holes 0:17:12.960 --> 0:17:16.600 as theoretical objects, right, Yeah, So a black hole is 0:17:16.640 --> 0:17:20.120 a region of space time that is so dense that nothing, 0:17:20.440 --> 0:17:23.840 not even light, can escape, And this of course means 0:17:23.880 --> 0:17:27.000 that you can't see a black hole. There's nothing to 0:17:27.080 --> 0:17:29.719 see because the only way we see things is if 0:17:29.760 --> 0:17:33.040 they emit or reflect light, and a black hole does neither. 0:17:33.320 --> 0:17:36.000 No light comes out of it. If light goes toward it, 0:17:36.000 --> 0:17:38.280 it doesn't bounce off and come back in your direction. 0:17:38.320 --> 0:17:42.680 It just gets absorbed and never escapes. Yeah, you know this, 0:17:42.680 --> 0:17:45.200 this reminds me a lot of how we're recently talking 0:17:45.200 --> 0:17:49.119 about casually about quantum mechanics. In a new book that 0:17:49.160 --> 0:17:52.920 you've read, about quantum mechanics and and and uh, and 0:17:53.240 --> 0:17:54.600 this is kind of that's kind of like the the 0:17:55.840 --> 0:17:59.760 micro quest and then the black holes are the macro 0:18:00.680 --> 0:18:03.359 quest and the macro into the spectrum. And you know, 0:18:03.440 --> 0:18:06.160 both of these are extremes that are just so far 0:18:06.280 --> 0:18:10.320 beyond our ability to you know, certainly our evolved ability 0:18:10.359 --> 0:18:15.159 to perceive and and to some extent even contemplate, you know, 0:18:15.240 --> 0:18:17.320 and and and and so we you know, we talk 0:18:17.359 --> 0:18:20.640 about like how we would perceive them vigitally, and even 0:18:20.680 --> 0:18:23.080 that is like when you really start turning that over 0:18:23.119 --> 0:18:27.040 in your head, um, it's it just gets ridiculous really quickly, 0:18:27.160 --> 0:18:28.879 you know. Well, it forces you to think about the 0:18:28.960 --> 0:18:31.760 nature of physical information. Yeah, the fact that you know, 0:18:31.800 --> 0:18:34.640 a black hole highlights the fact that when you see 0:18:34.640 --> 0:18:38.240 a thing, you never really see the thing. You're seeing 0:18:38.359 --> 0:18:40.680 light reflecting off of it, which is, you know, that's 0:18:40.680 --> 0:18:43.400 our most common way of sampling the world. So it 0:18:43.480 --> 0:18:46.000 makes sense to just think about that as a short cut. Yes, 0:18:46.040 --> 0:18:49.359 when I see the light bouncing off of a coffee cup, 0:18:49.640 --> 0:18:51.840 I see the coffee cup, but you're not, you know, 0:18:51.920 --> 0:18:54.720 you don't have the coffee cup within you from that, 0:18:54.800 --> 0:18:58.680 it's just light. Yeah, with our site, with with certainly 0:18:59.080 --> 0:19:04.119 healthy human side. We kind of have this illusion that 0:19:04.119 --> 0:19:07.640 that we that we are cited, that we can perceive. 0:19:07.960 --> 0:19:10.680 But the more we look at things like the microscopic world, 0:19:10.680 --> 0:19:14.000 in the macroscopic world, the inner space and and outer space, 0:19:14.880 --> 0:19:17.840 you really begin to feel that we are not cited 0:19:17.880 --> 0:19:22.080 at all. We are just so incredibly blind. And the 0:19:22.119 --> 0:19:25.280 only way that we are really really have been able 0:19:25.320 --> 0:19:31.080 to understand h nature has been through scientific inquiry that 0:19:31.160 --> 0:19:33.199 I guess you could you could relate to the like 0:19:33.240 --> 0:19:37.400 the blind pawing of of the blind men and the elephant, 0:19:37.480 --> 0:19:39.639 you know. Yeah, And astronomy is a great way to 0:19:39.760 --> 0:19:42.400 highlight that. Astronomy and well you pointed to both ends 0:19:42.400 --> 0:19:46.360 of the scale, you know, physical scale, the quantum mechanics 0:19:46.440 --> 0:19:49.800 world and astronomy what's out there in the dark beyond Earth. 0:19:50.480 --> 0:19:54.320 They both really highlight ways in which the universe is 0:19:54.440 --> 0:19:59.240 full of hugely powerful, consequential phenomena that we not only 0:19:59.560 --> 0:20:03.760 don't regularly see, but we can't even understand when we 0:20:03.960 --> 0:20:06.440 when we detect it with other means right and in 0:20:06.560 --> 0:20:09.880 both totally violates our intuitions and in both directions, both 0:20:09.920 --> 0:20:13.280 towards the small and the large. You know, we can 0:20:13.320 --> 0:20:18.240 optically enhance the telescope or the microscope, but in both 0:20:18.280 --> 0:20:22.000 directions there reaches a point where optical enhancement uh doesn't 0:20:22.040 --> 0:20:24.120 get you anywhere, and we have to rely on other 0:20:24.320 --> 0:20:28.320 means of of pawing at the uh you know, at 0:20:28.359 --> 0:20:31.080 the the the the the Titanic forces on an either 0:20:31.200 --> 0:20:33.399 end of the spectrum. And that's something that, of course, 0:20:33.400 --> 0:20:36.159 we get to with Jansky's discovery, right, this idea that 0:20:36.480 --> 0:20:40.680 there are these powerful sources of information coming into the Earth, 0:20:40.720 --> 0:20:42.720 but it's not information that anybody would be able to 0:20:42.760 --> 0:20:46.360 see with their eyes coming in radio frequencies and then uh, 0:20:46.400 --> 0:20:49.280 you know, other frequencies of light. But I guess to 0:20:49.320 --> 0:20:51.560 get back to black holes, we should ask the question, 0:20:51.600 --> 0:20:54.320 of course, how is it possible for an object to 0:20:54.400 --> 0:20:57.240 be so dense that it neither reflects nor amidst light? 0:20:57.320 --> 0:20:59.600 Like what what happens to the light when it goes in? 0:20:59.720 --> 0:21:03.680 Why that be the case? Uh? So, the basic principle 0:21:03.760 --> 0:21:05.920 is the greater the mass of an object, the more 0:21:06.000 --> 0:21:10.000 difficult it is for an object that is moving away 0:21:10.040 --> 0:21:13.440 from it to escape its gravity. Well, now, all sources 0:21:13.480 --> 0:21:17.040 of gravity have their own particular escape velocity and If 0:21:17.080 --> 0:21:19.240 I'm standing on the surface of the Earth and I 0:21:19.280 --> 0:21:21.119 throw a cantalope straight up in the air at a 0:21:21.200 --> 0:21:23.760 hundred kilometers an hour, it's of course going to fall 0:21:23.760 --> 0:21:26.000 back down to the ground. If I throw the cantle 0:21:26.040 --> 0:21:28.440 ope at two hundred kilometers per hour, it's going to 0:21:28.560 --> 0:21:31.200 go up farther, but of course it will eventually slow down, 0:21:31.320 --> 0:21:33.960 reverse course and fall back to the Earth. But if 0:21:33.960 --> 0:21:36.359 I keep throwing it up in the air greater and 0:21:36.400 --> 0:21:40.119 greater velocities each time, eventually you will reach some velocity 0:21:40.400 --> 0:21:43.399 where the cantalope doesn't fall straight back down to the ground, 0:21:43.600 --> 0:21:45.320 but it goes up and up and up, and it 0:21:45.359 --> 0:21:47.919 breaks free of Earth's gravity, and then it just keeps 0:21:47.960 --> 0:21:51.239 on flying out into space. It maintains its momentum and 0:21:51.280 --> 0:21:53.439 goes in the other direction. Now at the surface of 0:21:53.480 --> 0:21:56.800 the Earth, this velocity for objects that don't keep propelling 0:21:56.840 --> 0:22:01.159 themselves as they travel, is about eleven point twokilometers per second, 0:22:01.240 --> 0:22:05.200 so it's very fast. Humans have never made a terrestrial 0:22:05.359 --> 0:22:08.760 vehicle that goes even close to this fast with humans 0:22:08.760 --> 0:22:12.680 in it. Certainly, our our launch vehicles that put things 0:22:12.720 --> 0:22:15.399