WEBVTT 1 00:00:03.399 --> 00:00:07.719 Welcome to Bedtime Astronomy. Explore the wonders of the cosmos 2 00:00:07.759 --> 00:00:12.279 with our soothing Bedtime Astronomie podcast. Each episode offers a 3 00:00:12.359 --> 00:00:16.320 gentle journey through the stars, planets, and beyond, perfect for 4 00:00:16.399 --> 00:00:20.239 unwinding after a long day. Let's travel through the mysteries 5 00:00:20.239 --> 00:00:22.440 of the universe as you drift off into a peaceful 6 00:00:22.480 --> 00:00:23.800 slumber under the night sky. 7 00:00:26.960 --> 00:00:30.559 Imagine for a second, you're just looking up at the 8 00:00:30.640 --> 00:00:33.119 night sky, right right, just taking it in. Yeah, and 9 00:00:33.159 --> 00:00:36.039 you're watching one of the absolute brightest street lights in 10 00:00:36.079 --> 00:00:40.880 the entire universe simply turn off, just completely go dark exactly. 11 00:00:40.920 --> 00:00:43.119 And I don't mean fading away over millions of years 12 00:00:43.119 --> 00:00:46.600 as the cosmos slowly ages. I mean we are talking 13 00:00:46.640 --> 00:00:50.840 about a beacon so luminous that it outshines entire galaxies 14 00:00:50.920 --> 00:00:54.600 oh easily, and it dims so incredibly fast that you 15 00:00:54.759 --> 00:00:57.799 actually witness it happen within a fraction of your own lifetime. 16 00:00:58.200 --> 00:01:02.840 It's it really is a staggering image, and I think 17 00:01:02.840 --> 00:01:07.400 it fundamentally breaks how we are taught to perceive the cosmos, right, 18 00:01:07.560 --> 00:01:10.239 because we're basically conditioned to view the universe as this 19 00:01:11.000 --> 00:01:11.879 static painting. 20 00:01:12.000 --> 00:01:14.359 Yeah, Like it's unchanging exactly. 21 00:01:14.480 --> 00:01:17.120 We just assume that astronomical changes happen on these massive 22 00:01:17.159 --> 00:01:21.480 time scales that render a single human life practically invisible. 23 00:01:21.079 --> 00:01:22.879 A blink of an eye, right, But. 24 00:01:22.879 --> 00:01:27.239 The event we're gysecting today it proves that assumption completely 25 00:01:27.439 --> 00:01:28.439 undeniably wrong. 26 00:01:28.879 --> 00:01:32.400 And that is exactly our mission today. We are taking 27 00:01:32.439 --> 00:01:36.400 a journey roughly ten billion light years across the universe 28 00:01:36.760 --> 00:01:42.439 to explore a cosmic anomaly that is frankly forcing astrophysicists 29 00:01:42.480 --> 00:01:44.480 to rewrite the entire rule book. 30 00:01:44.599 --> 00:01:45.560 Yeah, they really are. 31 00:01:45.840 --> 00:01:49.760 We are investigating the sudden, dramatic and honestly pretty violent 32 00:01:49.920 --> 00:01:52.519 dimming of a very distant galaxy. 33 00:01:52.680 --> 00:01:54.519 Violent is definitely the right word for it. 34 00:01:54.560 --> 00:01:56.560 And by the time we're done here, you'll understand the 35 00:01:56.959 --> 00:02:01.200 intricate machinery that powers the brightest objects in the cosmos. 36 00:02:00.760 --> 00:02:02.200 Which is fascinating in itself. 37 00:02:02.239 --> 00:02:05.959 Oh absolutely. Plus you'll see how astronomical cold case detectives 38 00:02:06.079 --> 00:02:09.919 essentially use seventy year old evidence to solve modern mysteries. 39 00:02:10.000 --> 00:02:11.240 I love that part of the story. 40 00:02:11.319 --> 00:02:13.680 It's so good. And we'll get into why everything we 41 00:02:13.719 --> 00:02:16.080 thought we knew about the life span of supermassive black 42 00:02:16.080 --> 00:02:18.879 holes might just need to be thrown right out the window. 43 00:02:19.159 --> 00:02:23.919 Yeah, because to really appreciate the shockwave, this scent through 44 00:02:23.960 --> 00:02:27.159 the astrophysics community, we first have to, well, we have 45 00:02:27.199 --> 00:02:30.080 to establish the scene of the cosmic crime, so to speak. 46 00:02:30.199 --> 00:02:31.719 Right, let's set the stage. Where are we looking? 47 00:02:31.960 --> 00:02:36.919 So the focus is this specific incredibly distant galaxy. It's 48 00:02:37.000 --> 00:02:39.560 cataloged is JA zero two one eight minus serio zero 49 00:02:39.560 --> 00:02:43.439 three at six. Patchy name, very catchy, right, standard astronomical naming. 50 00:02:44.120 --> 00:02:47.639 But astronomers measure the distance to these far off objects 51 00:02:47.680 --> 00:02:50.199 using a metric called red shift. Okay, and Jay zero 52 00:02:50.319 --> 00:02:52.400 two one eight has a red shift of one point eight. 53 00:02:52.639 --> 00:02:54.800 Let's actually break down what a red shift of one 54 00:02:54.800 --> 00:02:57.560 point eight actually means, because you know, it's not just 55 00:02:57.599 --> 00:02:59.000 a physical distance. 56 00:02:58.680 --> 00:03:00.439 Right, It's not just miles or coldometers. 57 00:03:00.520 --> 00:03:04.080 No, it's a temporal distance. It's time because light takes 58 00:03:04.080 --> 00:03:07.759 time to travel. Looking across space is quite literally looking 59 00:03:07.800 --> 00:03:12.080 back in time, cosmic time machine exactly. It's like receiving 60 00:03:12.080 --> 00:03:14.599 a postcard in the mail that took ten billion years 61 00:03:14.639 --> 00:03:15.120 to arrive. 62 00:03:15.280 --> 00:03:16.280 That's a great way to put it. 63 00:03:16.319 --> 00:03:18.879 And the unsettling part is, as you're holding this ancient 64 00:03:18.919 --> 00:03:22.520 postcard in your hands, the picture on the front drastically 65 00:03:22.560 --> 00:03:24.080 fades right before your eyes. 66 00:03:24.240 --> 00:03:27.560 Yeah. That temporal aspect is so vital to understand because 67 00:03:27.560 --> 00:03:29.800 when we observe the light from j zero to le eight, 68 00:03:30.240 --> 00:03:32.159 we are seeing the universe as it was when it 69 00:03:32.240 --> 00:03:34.560 was only roughly a third of its current age. 70 00:03:34.680 --> 00:03:35.800 Wow, only a third. 71 00:03:36.039 --> 00:03:40.240 Yeah, this era around a redshift of two. Astronomers often 72 00:03:40.280 --> 00:03:42.360 referred to it as cosmic noon. 73 00:03:42.719 --> 00:03:45.120 Cosmic noon. That sounds intense. 74 00:03:45.240 --> 00:03:49.280 It was. It was this period of intense rapid star formation. 75 00:03:49.919 --> 00:03:54.280 Galaxies were incredibly active, chaotic, constantly colliding and merging. 76 00:03:54.439 --> 00:03:57.879 So finding a tremendously bright object in that specific era 77 00:03:58.039 --> 00:03:59.400 isn't really the surprise, right. 78 00:03:59.400 --> 00:04:01.759 Not at all. We expect things to be bright and 79 00:04:01.840 --> 00:04:05.400 violent back then. The shot came when an international team 80 00:04:05.479 --> 00:04:08.960 led by Tomochi Morrikuma at the Cheap Institute of Technology, 81 00:04:09.319 --> 00:04:11.599 when they discovered that the brightness of jayas zero two 82 00:04:11.599 --> 00:04:15.800 to ODA suddenly plummeted to just one twentieth of its 83 00:04:15.840 --> 00:04:19.240 original level. We're twentieth And the craziest part, it did 84 00:04:19.240 --> 00:04:21.600 this in merely twenty earth years see a. 85 00:04:21.560 --> 00:04:24.279 Twenty full drop. I mean that means we are looking 86 00:04:24.279 --> 00:04:27.319 at a system that went from operating at peak luminosity 87 00:04:27.399 --> 00:04:30.279 down to just five percent of its previous output five percent. 88 00:04:30.360 --> 00:04:33.000 If you're say, driving to work right now, think about 89 00:04:33.000 --> 00:04:35.800 the engine in your car. Okay, if your engine suddenly 90 00:04:35.800 --> 00:04:38.600 lost ninety five percent of its power, you wouldn't just 91 00:04:38.639 --> 00:04:39.839 call it a minor fluctuation. 92 00:04:40.000 --> 00:04:42.040 No, you'd pull over immediately, right. 93 00:04:42.079 --> 00:04:44.399 You would assume a catastrophic mechanical failure. 94 00:04:44.920 --> 00:04:47.720 That is a highly accurate way to frame it, actually, 95 00:04:48.199 --> 00:04:51.439 because an object visible from ten billion light years away 96 00:04:52.120 --> 00:04:56.319 is generating energy on a scale that completely defies everyday comprehension. 97 00:04:56.360 --> 00:04:59.680 It's unfathomable, truly, So to lose ninety five percent of 98 00:04:59.680 --> 00:05:03.480 that ma massive energy output in just two decades, it 99 00:05:03.600 --> 00:05:07.399 signals a complete systemic breakdown of the engine driving that light. 100 00:05:07.680 --> 00:05:10.279 Which brings us to the mechanics of the engine itself, 101 00:05:10.480 --> 00:05:13.639 because a twenty fold drop in brightness is massive. But 102 00:05:13.759 --> 00:05:16.199 to grasp the true scale of what was lost, we 103 00:05:16.240 --> 00:05:18.800 really need to understand what was generating all that light 104 00:05:18.839 --> 00:05:19.600 in the first place. 105 00:05:19.800 --> 00:05:21.759 Right, what's the fuel? What's the engine? 106 00:05:21.839 --> 00:05:24.160 Yeah, because we are just talking about a really big 107 00:05:24.199 --> 00:05:26.920 cluster of stars here, No, definitely not. We are talking 108 00:05:27.000 --> 00:05:30.600 about an active galactic nucleus or an agn Yeah, so. 109 00:05:30.600 --> 00:05:33.560 If we look at the anatomy of most large galaxies, 110 00:05:33.600 --> 00:05:37.079 including our own, actually we find a supermassive black hole 111 00:05:37.199 --> 00:05:37.839 right at the core. 112 00:05:38.000 --> 00:05:40.000 And when we say super massive, we are. 113 00:05:39.920 --> 00:05:43.279 Talking about an object with a mass of hundreds of millions, 114 00:05:43.399 --> 00:05:46.759 sometimes billions of times the mass of our own sun. 115 00:05:47.240 --> 00:05:49.480 Just compact it into a tiny point. 116 00:05:49.240 --> 00:05:53.600 Exactly, compacted into a relatively tiny region of space. Now, 117 00:05:53.680 --> 00:05:57.759 in a quiet galaxy like our Milky Way, the black 118 00:05:57.759 --> 00:06:01.519 hole is mostly dormant right sitting there, Yeah, it's fasting. 119 00:06:01.959 --> 00:06:06.480 But in an active galactic nucleus, the environment is violently chaotic. 120 00:06:06.800 --> 00:06:10.120 You have these immense clouds of gas and dust constantly 121 00:06:10.160 --> 00:06:12.639 being pulled inward by the black hole's gravity. 122 00:06:12.720 --> 00:06:15.199 But wait, knowing the engine is powered by a black 123 00:06:15.199 --> 00:06:18.519 hole makes this whole scenario sound incredibly counterintuitive to me. 124 00:06:18.879 --> 00:06:22.439 How so, Well, we all know the fundamental rule of astrophysics, right, 125 00:06:23.120 --> 00:06:27.319 nothing escapes the event horizon, right, not even light exactly. 126 00:06:27.839 --> 00:06:32.120 Black Holes are the ultimate cosmic vacuum cleaners. They trap light. 127 00:06:32.680 --> 00:06:35.439 So how is it that the area immediately surrounding the 128 00:06:35.519 --> 00:06:38.800 darkest object in the universe somehow becomes the brightest thing 129 00:06:38.839 --> 00:06:39.959 we can possibly see. 130 00:06:40.079 --> 00:06:43.480 It is honestly one of the most beautiful paradoxes in physics. 131 00:06:43.639 --> 00:06:46.120 I mean, is it purely just the friction of some 132 00:06:46.199 --> 00:06:47.199 cosmic traffic gem. 133 00:06:47.399 --> 00:06:49.639 That's a huge part of it. The key is really 134 00:06:49.680 --> 00:06:52.399 differentiating the black hole itself from its surrounding environment. 135 00:06:52.480 --> 00:06:55.120 Okay, separate the hole from the waiting room exactly. 136 00:06:55.759 --> 00:06:59.639 The event horizon is the boundary of no return. But 137 00:06:59.720 --> 00:07:03.680 the light we see from an agn isn't coming from inside. 138 00:07:03.199 --> 00:07:06.040 The black hole, obviously not because we wouldn't see it. 139 00:07:06.040 --> 00:07:08.560 Right, It's coming from the accretion disc, that is, the 140 00:07:08.560 --> 00:07:11.480 waiting room of material just outside the event horizon. 141 00:07:11.560 --> 00:07:13.160 So what's happening in that waiting room? 142 00:07:13.360 --> 00:07:17.319 Well, as gas is pulled inward, conservation of angular momentum 143 00:07:17.399 --> 00:07:19.199 forces it to swirl around. 144 00:07:18.920 --> 00:07:21.800 The black hole, kind of like water circling a drain. 145 00:07:22.000 --> 00:07:24.959 Exactly like that, right, And it flattens out into this vast, 146 00:07:25.160 --> 00:07:27.639 incredibly dense whirlpool of plasma. 147 00:07:27.759 --> 00:07:30.319 And as that plasma spirals closer and closer to the 148 00:07:30.360 --> 00:07:32.959 event horizon, it accelerates massively. 149 00:07:33.240 --> 00:07:36.079 The inner tracks of this whirlpool are spinning at a 150 00:07:36.160 --> 00:07:39.240 significant fraction of the speed of light. Wow. Meanwhile, the 151 00:07:39.279 --> 00:07:41.199 outer tracks are moving much much slower. 152 00:07:41.519 --> 00:07:44.120 Ah. Okay, so the inner lanes of the highway are 153 00:07:44.160 --> 00:07:47.639 moving at near light speed and the outer lanes are sluggish. 154 00:07:47.720 --> 00:07:52.000 Yes, And that differential rotation creates something we rarely associate 155 00:07:52.040 --> 00:07:54.839 with the vacuum of space, which is profound. 156 00:07:54.399 --> 00:07:56.519 Friction because things are rubbing together. 157 00:07:57.040 --> 00:08:01.040 But it's not the simple mechanical friction of two solid 158 00:08:01.040 --> 00:08:04.800 objects rubbing together, like rubbing your hands to get warm. 159 00:08:04.680 --> 00:08:06.360 Right, because it's gas. 160 00:08:06.160 --> 00:08:09.360 Well, it's plasma. They're dealing with plasma physics here, So 161 00:08:09.399 --> 00:08:12.560 the friction is actually driven by magnetic fields threading through 162 00:08:12.560 --> 00:08:13.639 this ionized gas. 163 00:08:13.720 --> 00:08:14.480 Oh interesting. 164 00:08:14.639 --> 00:08:17.800 Yeah, As these layers of plasma sheer against each other 165 00:08:17.839 --> 00:08:23.519 at relativistic speeds, it triggers a phenomenon called magnetor rotational. 166 00:08:23.000 --> 00:08:26.639 Instability magneto rotational instability. 167 00:08:26.680 --> 00:08:29.240 That sounds like a mouthful it is, but basically it 168 00:08:29.319 --> 00:08:33.519 just creates immense violent turbulence within the disk, okay. And 169 00:08:33.559 --> 00:08:37.559 that turbulence is what converts the gravitational potential energy of 170 00:08:37.559 --> 00:08:40.399 the in falling gas into staggering amounts of heat. 171 00:08:40.519 --> 00:08:42.080 So we aren't just talking about the gas getting a 172 00:08:42.080 --> 00:08:43.639 little warm, no, No. 173 00:08:43.679 --> 00:08:47.279 The friction generated by these magnetic turbulent forces, heats the 174 00:08:47.320 --> 00:08:51.240 plasma to hundreds of thousands, sometimes millions of degrees. 175 00:08:51.399 --> 00:08:52.600 Millions of degrees. 176 00:08:52.679 --> 00:08:56.159 That is insane, and at those extreme temperatures, the gas 177 00:08:56.200 --> 00:08:59.799 glows brilliantly across the entire electromagnetic spectrum. 178 00:09:00.000 --> 00:09:02.120 So it's basically screaming as it falls in. 179 00:09:02.559 --> 00:09:05.480 Exactly, it's the death cry of the gas just before 180 00:09:05.480 --> 00:09:10.519 it crosses the event horizon. And the efficiency of this 181 00:09:10.639 --> 00:09:13.200 process is difficult to overstate. 182 00:09:13.440 --> 00:09:16.320 How efficient is it compared to say, a star. 183 00:09:16.519 --> 00:09:20.679 It's wildly more efficient. Dropping mass into a supermassive black 184 00:09:20.679 --> 00:09:23.559 hole via an accretion disc is actually one of the 185 00:09:23.559 --> 00:09:26.960 most efficient ways to generate energy in the known universe. 186 00:09:27.039 --> 00:09:29.200 Wait, really more than fusion. 187 00:09:28.919 --> 00:09:31.879 Far more efficient than the nuclear fusion powering stars like 188 00:09:31.919 --> 00:09:32.320 our sun. 189 00:09:32.519 --> 00:09:33.279 I had no idea. 190 00:09:33.440 --> 00:09:37.240 Yeah, that is exactly why a single agn can outshine 191 00:09:37.320 --> 00:09:39.120 hundreds of billions of stars combined. 192 00:09:39.480 --> 00:09:42.639 Okay, so we have established this blindingly bright vortex of 193 00:09:42.720 --> 00:09:46.360 superheated plasma rueled by the immense gravity of a monster 194 00:09:46.480 --> 00:09:49.720 black hole pumping out more energy than entire galaxies. 195 00:09:49.799 --> 00:09:50.559 That's the engine. 196 00:09:50.600 --> 00:09:53.039 But knowing that the engine is a massive accretion disc 197 00:09:53.360 --> 00:09:56.399 makes this rapid shut down even more impossible to believe 198 00:09:56.559 --> 00:09:59.279 it really does, because we are talking about physical structures 199 00:09:59.279 --> 00:10:00.679 that are light years cross right. 200 00:10:00.799 --> 00:10:02.600 Sometimes yes, they are immense. 201 00:10:02.919 --> 00:10:06.919 So the inertia alone means an engine that massive physically 202 00:10:06.960 --> 00:10:09.720 cannot stop that fast. You can't hit the brakes on 203 00:10:09.759 --> 00:10:12.519 something light years wide and expect it to halt in 204 00:10:12.559 --> 00:10:13.200 twenty years. 205 00:10:13.440 --> 00:10:16.039 And that right there is the twenty year glitch. Yeah, 206 00:10:16.039 --> 00:10:18.799 that is exactly where standard physics breaks down in this case. 207 00:10:18.879 --> 00:10:20.799 Okay, so let's dig into that glitch. What is the 208 00:10:20.879 --> 00:10:22.600 normal behavior supposed to. 209 00:10:22.519 --> 00:10:25.720 Be to understand the anomaly? We have to establish that 210 00:10:25.799 --> 00:10:30.600 baseline of normal behavior. Active glactic nuclei do vary in brightness, 211 00:10:30.799 --> 00:10:31.639 that is known, right. 212 00:10:31.639 --> 00:10:33.159 They aren't perfectly steady. 213 00:10:32.879 --> 00:10:36.639 Because the flow of gas into the disc is turbulent 214 00:10:36.720 --> 00:10:41.039 and clumpy. It's not a perfectly smooth stream. Because of this, 215 00:10:41.279 --> 00:10:44.000 it is completely standard for an agn to vary in 216 00:10:44.039 --> 00:10:48.000 its luminous output by about thirty percent over months or 217 00:10:48.039 --> 00:10:48.639 even years. 218 00:10:48.759 --> 00:10:51.320 Okay, so a thirty percent variation that makes sense to me. 219 00:10:51.399 --> 00:10:53.519 That's like a flickering light bulb on your front porch. 220 00:10:53.720 --> 00:10:53.840 Right. 221 00:10:54.399 --> 00:10:57.639 Sometimes the current waivers a bit, the filament cools for 222 00:10:57.679 --> 00:11:00.000 a microsecond, and it dims, then it brightens again. 223 00:11:00.279 --> 00:11:02.720 A perfect analogy. That's just the normal breathing. 224 00:11:02.399 --> 00:11:05.000 Of the accretion disc, but dropping to five percent of 225 00:11:05.039 --> 00:11:07.840 its original brightness, dropping by a factor of twenty. 226 00:11:08.080 --> 00:11:08.840 Yeah, that's different. 227 00:11:08.919 --> 00:11:11.120 That is not a flicker. That's someone walking over and 228 00:11:11.240 --> 00:11:13.840 violently ripping the power cable right out of the wall. 229 00:11:14.039 --> 00:11:18.200 Exactly. And when astrophysicists build models to describe the physics 230 00:11:18.200 --> 00:11:22.919 of these accretion discs, they deal with very specific mathematical time. 231 00:11:22.639 --> 00:11:24.159 Scales, well kind of timescales. 232 00:11:24.320 --> 00:11:27.480 Well, there is the dynamical time scale, which dictates how 233 00:11:27.519 --> 00:11:30.679 fast things orbit the black hole. Okay, but more importantly 234 00:11:30.720 --> 00:11:33.799 for this mystery, there is the viscous timescale. 235 00:11:33.879 --> 00:11:36.320 This is like viscosity, like honey. 236 00:11:36.559 --> 00:11:40.000 Exactly, it's the time it takes for mass to actually 237 00:11:40.039 --> 00:11:43.000 flow through the friction of the disk and eventually fall 238 00:11:43.000 --> 00:11:43.919 into the black hole. 239 00:11:44.080 --> 00:11:45.360 Ah, I see. 240 00:11:45.399 --> 00:11:49.480 And for a supermassive black hole, the viscous timescale is 241 00:11:49.559 --> 00:11:53.679 immense changes in the fundamental mass secretion rate. The actual 242 00:11:53.759 --> 00:11:57.440 fueling of the black hole should happen incredibly slowly, slowly 243 00:11:57.480 --> 00:12:00.240 over tens of thousands of years at the absolute. 244 00:11:59.799 --> 00:12:03.240 Mid So, meaning if you hypothetically cut off the fuel 245 00:12:03.240 --> 00:12:05.799 supply at the outer edge of the disc today. Yes, 246 00:12:05.960 --> 00:12:08.200 it should still take tens of thousands of years for 247 00:12:08.240 --> 00:12:09.919 the inner part of the disk to finally drain out 248 00:12:09.919 --> 00:12:10.519 and go dark. 249 00:12:10.759 --> 00:12:14.679 Yes, the math simply does not allow an object containing 250 00:12:14.759 --> 00:12:18.039 hundreds of millions of solar masses to shut down its 251 00:12:18.039 --> 00:12:20.120 primary energy generation in twenty years. 252 00:12:20.399 --> 00:12:21.799 It's just too fast. 253 00:12:21.600 --> 00:12:24.159 Way too fast. To put it in geological terms, down 254 00:12:24.200 --> 00:12:27.519 here on Earth, it is equivalent to watching the entire 255 00:12:27.879 --> 00:12:32.279 Himalayan mountain range completely level out into a flat plane overnight. Wow, 256 00:12:32.440 --> 00:12:34.120 just wake up and the mountains are gone. 257 00:12:34.200 --> 00:12:37.320 And if a geologist saw the Himalays flatten overnight, their 258 00:12:37.360 --> 00:12:40.320 first instinct would be to assume their equipment was broken. 259 00:12:40.679 --> 00:12:43.080 Exactly. You check your sensors, right. 260 00:12:43.159 --> 00:12:46.360 You can't just claim you broke standard physics without bringing absolute, 261 00:12:46.480 --> 00:12:47.879 ironclad receipts. 262 00:12:47.960 --> 00:12:49.240 And these researchers knew that. 263 00:12:49.639 --> 00:12:53.080 So to prove this wasn't just some instrument error, astronomers 264 00:12:53.120 --> 00:12:57.120 had to pull together an unprecedented multi generational investigation, and. 265 00:12:57.039 --> 00:13:01.120 The methodology they used is just a masterclass in ovational astronomy. 266 00:13:01.399 --> 00:13:04.759 Let's walk through that detective work, because it's fascinating. 267 00:13:04.240 --> 00:13:07.559 It really is. The discovery wasn't a sudden eureka moment 268 00:13:07.960 --> 00:13:10.200 at a telescope by piece where someone. 269 00:13:10.039 --> 00:13:12.559 Gasped, you know, right, It's not like in the movies. 270 00:13:12.919 --> 00:13:16.519 No, It relied on comparing immense digital data sets that 271 00:13:16.559 --> 00:13:20.080 were separated by nearly two decades and then corroborating all 272 00:13:20.080 --> 00:13:21.679 of that with historical archives. 273 00:13:21.759 --> 00:13:24.279 Okay, so where does the timeline start. 274 00:13:24.720 --> 00:13:28.639 The before picture? The baseline of this roaring bright agn 275 00:13:29.120 --> 00:13:31.919 was established around two thousand and two by the Sloan 276 00:13:32.000 --> 00:13:33.000 Digital Sky Survey. 277 00:13:33.080 --> 00:13:36.960 Okay, the SDSS, that's pretty legendary and astronomy circles right. 278 00:13:36.840 --> 00:13:39.559 Oh, absolutely. It wasn't just looking at individual objects. It 279 00:13:39.679 --> 00:13:43.840 essentially created one of the first highly detailed, massive three 280 00:13:43.960 --> 00:13:46.200 D maps of the observable universe. 281 00:13:46.039 --> 00:13:49.399 Scanning massive swaths of the sky night after night. 282 00:13:49.480 --> 00:13:52.039 Exactly, and it provided a vital benchmark for what the 283 00:13:52.039 --> 00:13:53.879 sky looked like at the turn of the millennium. 284 00:13:54.000 --> 00:13:57.399 Right, But obviously, astronomy technology evolves incredibly rapidly. 285 00:13:57.559 --> 00:14:00.360 It does. Fast forward to twenty eighteen and re searchers 286 00:14:00.360 --> 00:14:03.600 were using the hypersuprimecam the HC right mounted on the 287 00:14:03.639 --> 00:14:07.360 super Bru telescope in Hawaii. The HSC uses these highly 288 00:14:07.399 --> 00:14:11.559 advanced charge coupled devices that are far, far more sensitive 289 00:14:11.600 --> 00:14:13.639 than what was available back in two thousand and two. 290 00:14:13.480 --> 00:14:14.799 So they get a much crisper look. 291 00:14:15.279 --> 00:14:19.000 Exactly. So this international collaboration, which by the way, required 292 00:14:19.159 --> 00:14:25.279 coordinating massive teams across Japan, Germany and Spain just to 293 00:14:25.320 --> 00:14:27.639 process the sheer volume of data. 294 00:14:27.759 --> 00:14:29.879 Just moving the hard drives must have been a nightmare. 295 00:14:29.919 --> 00:14:34.000 Seriously. But when they compared the twenty eighteen HSC images 296 00:14:34.039 --> 00:14:37.600 to the two thousand and two SDSS data, the discrepancy 297 00:14:37.639 --> 00:14:39.840 in Jay zero two eighteen was glaring. 298 00:14:40.120 --> 00:14:41.759 The light had simply vanished. 299 00:14:41.759 --> 00:14:42.519 It is just gone. 300 00:14:42.559 --> 00:14:45.720 But seeing a discrepancy between two digital surveys is you know, 301 00:14:45.879 --> 00:14:48.080 it's a great start, but it's not enough to rewrite 302 00:14:48.080 --> 00:14:48.559 the text. 303 00:14:48.399 --> 00:14:50.960 Posts and nave and close. You need confirmation, right. 304 00:14:50.879 --> 00:14:53.279 So they launched this massive follow up campaign. 305 00:14:53.320 --> 00:14:54.600 They threw everything they had at it. 306 00:14:54.600 --> 00:14:57.399 They brought in the Grand Telescopeio Canarias. They brought in 307 00:14:57.440 --> 00:15:02.600 the WMCC Observatory for new optical and near infrared observations. Yeah, 308 00:15:02.639 --> 00:15:04.919 they pulled in X ray data, they pulled in radio 309 00:15:05.000 --> 00:15:05.919 wave data. 310 00:15:05.720 --> 00:15:06.840 All across the spectrum. 311 00:15:06.879 --> 00:15:09.279 And then my absolute favorite part, They went into the 312 00:15:09.320 --> 00:15:14.200 physical vaults. Yes, the archival sleuthing scientists literally pulled out 313 00:15:14.240 --> 00:15:18.279 physical photographic plates taken roughly seventy years ago to build 314 00:15:18.279 --> 00:15:20.679 a complete historical timeline of this galaxy. 315 00:15:21.039 --> 00:15:23.879 It really is a stunning validation of the importance of 316 00:15:23.960 --> 00:15:25.519 preserving archival data. 317 00:15:25.559 --> 00:15:28.679 I mean seventy years ago. We are talking about chemical. 318 00:15:28.360 --> 00:15:32.960 Emulsions, long before digital sensors ever existed. But those old 319 00:15:33.000 --> 00:15:36.879 plates allowed the team to confirm that this sudden dimming 320 00:15:37.120 --> 00:15:40.519 wasn't just a return to some historical norm ah Okay, 321 00:15:40.639 --> 00:15:42.879 it allowed them to track the long term behavior of 322 00:15:42.919 --> 00:15:46.960 the agn over decades and definitively confirmed that the twenty 323 00:15:47.039 --> 00:15:51.600 year drop was a genuine, unprecedented anomaly in the object's history. 324 00:15:51.679 --> 00:15:53.360 Okay, hold on, I have to push back on the 325 00:15:53.360 --> 00:15:56.320 methodology here for a second. Sure, I love the idea 326 00:15:56.480 --> 00:15:59.960 of modern astronomers dusting off seventy year old physical place, 327 00:16:00.720 --> 00:16:02.919 but you're telling me a piece of glass coded in 328 00:16:03.000 --> 00:16:06.159 chemicals from the nineteen fifties is being used to verify 329 00:16:06.279 --> 00:16:08.519 a ten billion year old cosmic anomaly. 330 00:16:08.720 --> 00:16:10.039 That is exactly what I'm telling you. 331 00:16:10.240 --> 00:16:12.399 But how do we know the emulsion on those plates 332 00:16:12.440 --> 00:16:15.480 hasn't just degraded over the decades. How can we trust 333 00:16:15.519 --> 00:16:17.559 an old piece of glass sitting in a drawer to 334 00:16:17.679 --> 00:16:19.879 rewrite modern astrophysics. 335 00:16:20.000 --> 00:16:23.000 It is a very valid skepticism, and it's something astronomers 336 00:16:23.080 --> 00:16:25.919 actively account for through rigorous calibration. 337 00:16:26.320 --> 00:16:29.279 Okay, how do they calibrate a seventy year old photo. 338 00:16:29.879 --> 00:16:32.559 Well, you don't just look at the single galaxy on 339 00:16:32.600 --> 00:16:35.720 the glass plate in isolation. You look at the entire 340 00:16:35.799 --> 00:16:39.360 field of view captured on that piece of glass. Okay, 341 00:16:39.639 --> 00:16:42.919 you measure the brightness of Jay zero two eighteen against 342 00:16:42.919 --> 00:16:47.240 the brightness of dozens of steady, non variable stars they 343 00:16:47.320 --> 00:16:49.840 were captured on that exact same photographic plate. 344 00:16:50.120 --> 00:16:51.519 Oh I see right. 345 00:16:51.600 --> 00:16:55.360 So if the chemical emulsion simply degraded over time, the 346 00:16:55.440 --> 00:16:57.360 reference stars would also look dimmer to us. 347 00:16:57.399 --> 00:16:58.919 Now, that is brilliant. 348 00:16:59.039 --> 00:17:02.120 By measuring the relative brightness between the galaxy and those 349 00:17:02.159 --> 00:17:05.680 steady stars, the chemical degradation of the physical plate is 350 00:17:05.759 --> 00:17:07.319 completely factored out of the equation. 351 00:17:07.480 --> 00:17:10.079 Okay, that makes perfect sense. The steady stars act as 352 00:17:10.079 --> 00:17:12.680 an internal control group for the plate's physical condition. 353 00:17:12.839 --> 00:17:14.640 Exactly. It's very clever, it is. 354 00:17:14.920 --> 00:17:16.799 But let's look at the modern follow up data they 355 00:17:16.839 --> 00:17:19.000 gather because I have another question there. Shoot, why did 356 00:17:19.000 --> 00:17:22.359 they need radio X ray and optical data? I mean, 357 00:17:22.359 --> 00:17:25.559 if the light went out, shouldn't a regular standard visible 358 00:17:25.599 --> 00:17:28.559 light telescope be enough to tell us that? Why throw 359 00:17:28.599 --> 00:17:31.000 the entire electromagnetic spectrum of the problem. 360 00:17:31.079 --> 00:17:35.359 Because different wavelengths of light review entirely different physical mechanisms 361 00:17:35.400 --> 00:17:37.960 within the ag in itself. Okay, explain that if you 362 00:17:38.000 --> 00:17:41.079 only look at visible light the optical stuff, you miss 363 00:17:41.160 --> 00:17:44.039 the vast majority of the actual physics going on. Yeah, 364 00:17:44.079 --> 00:17:48.559 An active glyphic nucleus is a complex layered ecosystem. 365 00:17:48.680 --> 00:17:50.240 It's not just one glowing ball. 366 00:17:50.720 --> 00:17:54.599 No, it is governed by extreme thermal gradients. So the 367 00:17:54.599 --> 00:17:57.759 inner region right next to the black hole is the hottest. 368 00:17:57.359 --> 00:18:00.359 Part, right where the friction is crazy exactly. 369 00:18:00.039 --> 00:18:02.839 Because it's so hot, it produces high energy short wavelength 370 00:18:02.880 --> 00:18:03.160 X ray. 371 00:18:03.319 --> 00:18:05.000 So it's kind of like the blue flame on a 372 00:18:05.000 --> 00:18:07.680 blowtorch being hotter than the yellow flame on a candle. 373 00:18:07.839 --> 00:18:11.279 That is a fantastic parallel. Yes, Okay, Then the swirling 374 00:18:11.319 --> 00:18:14.839 gas further out from the center is slightly cooler, relatively speaking, 375 00:18:15.160 --> 00:18:17.400 so that produces your optical and ultraviolet light. 376 00:18:17.599 --> 00:18:19.559 So that's the yellow flame, right. 377 00:18:19.359 --> 00:18:21.759 And then even further away from the black hole, you 378 00:18:21.839 --> 00:18:25.920 have this massive torus, essentially a giant donut shape of 379 00:18:25.960 --> 00:18:29.039 cosmic dust, a dust donut, a dust donut, and that 380 00:18:29.160 --> 00:18:32.720 dust actually absorbs the inner light and reradiates it as 381 00:18:32.799 --> 00:18:34.359 long wavelength infrared heat. 382 00:18:34.599 --> 00:18:36.680 Oh wow, So you have X rays in the middle, 383 00:18:36.880 --> 00:18:39.799 optical in the middle ring, and infrared on the outer edge. 384 00:18:39.880 --> 00:18:43.200 Phcisely. So by looking at all these different wavelengths, researchers 385 00:18:43.240 --> 00:18:45.200 aren't just checking to see if the object as a 386 00:18:45.200 --> 00:18:46.279 whole got darker. 387 00:18:46.640 --> 00:18:49.880 They are diagnosing which specific parts of the engine. 388 00:18:49.599 --> 00:18:53.799 Broke down exactly. They're checking the spark plugs, the fuel line, everything. 389 00:18:53.559 --> 00:18:57.119 And more importantly, using those different wavelengths was the only 390 00:18:57.200 --> 00:19:01.720 way to rule out the absolute most common suspect and astronomical. 391 00:19:01.000 --> 00:19:02.960 Mysteries, which is cosmic dust. 392 00:19:03.240 --> 00:19:08.079 Exactly because whenever something gets unexpectedly dim in space, it 393 00:19:08.119 --> 00:19:10.720 feels like the first instinct is always did a giant 394 00:19:10.759 --> 00:19:12.960 cloud of dust just float in front of it? 395 00:19:12.960 --> 00:19:15.759 It is the most logical assumption based on Okham's razor. 396 00:19:16.079 --> 00:19:20.920 I mean, space is incredibly dusty, right, Galaxies are filled 397 00:19:20.960 --> 00:19:24.920 with these immense, sweeping clouds of silicates and carbonaceous grains 398 00:19:24.960 --> 00:19:27.039 that were forged in the depths of older stars. 399 00:19:27.119 --> 00:19:29.079 It's very crowded, very so. 400 00:19:29.240 --> 00:19:31.160 The most obvious answer to the question why did the 401 00:19:31.200 --> 00:19:34.559