WEBVTT 1 00:00:03.439 --> 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 00:00:26.920 --> 00:00:31.039 I want you to imagine an object that is just 8 00:00:31.320 --> 00:00:35.880 so unbelievably dense, possessing such an incomprehensible amount of mass 9 00:00:36.119 --> 00:00:38.479 that it weighs a billion times more than our own. 10 00:00:38.359 --> 00:00:40.399 Sun, which is I mean, it's a scale. It just 11 00:00:40.399 --> 00:00:42.240 totally defies human intuition. 12 00:00:42.000 --> 00:00:43.920 Right, it breaks your brain a little bit. Yeah, But 13 00:00:44.039 --> 00:00:46.799 take that image, that unimaginable behemoth, and I want you 14 00:00:46.799 --> 00:00:49.000 to put a second one right next to it. Oh man, Yeah, 15 00:00:49.079 --> 00:00:51.960 picture of these two galactic giants and they're locked in 16 00:00:52.000 --> 00:00:56.719 this high speed, inescapable binary orbit, just whipping around each other, 17 00:00:56.799 --> 00:01:01.039 mere moments away from a cosmic collision that is literally 18 00:01:01.079 --> 00:01:04.120 going to warp the foundational architecture of the universe itself. 19 00:01:04.319 --> 00:01:08.359 The kinetic energy and the gravitational forces involved at that scale, well, 20 00:01:08.560 --> 00:01:11.120 we are talking about the physical deformation of space time. 21 00:01:11.159 --> 00:01:14.840 Here it's being stretched and squeezed by two super massive 22 00:01:14.920 --> 00:01:17.959 objects in their final inspiral phase. 23 00:01:18.079 --> 00:01:21.000 And as of April twenty twenty six, this whole scenario 24 00:01:21.079 --> 00:01:24.280 has moved entirely out of the realm of theoretical modeling. Like, 25 00:01:24.359 --> 00:01:25.480 we aren't just guessing. 26 00:01:25.200 --> 00:01:26.239 Anymore, No, not at all. 27 00:01:26.280 --> 00:01:29.079 We have the data exactly. We are looking directly at 28 00:01:29.079 --> 00:01:33.079 the galaxy Marcian five oh one or MERK five oh one, 29 00:01:33.200 --> 00:01:35.840 which is positioned in the constellation Hercules. 30 00:01:35.400 --> 00:01:38.400 Right about four hundred and fifty six million light years away. 31 00:01:38.400 --> 00:01:43.000 And researchers have uncovered the very first direct, unambiguous evidence 32 00:01:43.120 --> 00:01:46.159 of a close pair of supermassive black holes on the 33 00:01:46.239 --> 00:01:47.719 absolute brink of merging. 34 00:01:47.799 --> 00:01:51.040 Which is huge because catching a binary system in this 35 00:01:51.239 --> 00:01:56.159 specific final act, it's been this decades long pursuit in astrophysics. 36 00:01:56.280 --> 00:01:58.319 We're going to completely unpack this today. We're going to 37 00:01:58.400 --> 00:02:01.799 map out the life cycle of these central galactic objects. 38 00:02:02.040 --> 00:02:05.400 Look really closely at the twenty three year long radio 39 00:02:05.400 --> 00:02:08.599 astronomy stakeout that cracked this specific system open, a. 40 00:02:08.599 --> 00:02:11.800 Literal stakeout, just staring at this galaxy for over two decades. 41 00:02:11.879 --> 00:02:13.960 Yeah, and we'll break down how the impending collision of 42 00:02:13.960 --> 00:02:16.520 Mercle five oh one is forcing this massive pivot in 43 00:02:16.560 --> 00:02:19.759 how we actually do astronomy, because when telescopes hit a 44 00:02:19.759 --> 00:02:22.800 hard physical wall, tracking a merger like this means we 45 00:02:22.840 --> 00:02:24.680 have to measure the gravity itself exactly. 46 00:02:24.680 --> 00:02:29.080 We basically have to transition from electromagnetic observation to gravitational 47 00:02:29.120 --> 00:02:31.319 wave tracking. It's the only way forward when they get 48 00:02:31.319 --> 00:02:31.800 this close. 49 00:02:32.080 --> 00:02:34.159 So before we get into the crazy mechanics of the 50 00:02:34.159 --> 00:02:37.000 collision in Marcarian five oh one, we really have to 51 00:02:37.039 --> 00:02:39.240 look at why this merger has to happen in the 52 00:02:39.280 --> 00:02:39.840 first place. 53 00:02:40.520 --> 00:02:43.719 The weight problem, right, the accretion problem. It's one of 54 00:02:43.759 --> 00:02:47.439 the sharpest constraints we have in black hole astrophysics. 55 00:02:46.840 --> 00:02:48.639 Because if you look at the mass of these objects 56 00:02:49.080 --> 00:02:53.319 hundreds of millions, sometimes billions of solar masses, the standard 57 00:02:53.360 --> 00:02:56.680 models of how they eat or to crete matter, they 58 00:02:56.800 --> 00:02:59.719 just failed to explain how they got so big within 59 00:02:59.719 --> 00:03:02.960 the teen point eight billion year timeline of the universe. 60 00:03:03.360 --> 00:03:05.879 Yeah, we know that supermassive black holes reside at the 61 00:03:05.879 --> 00:03:09.159 center of virtually every large galaxy. I mean, we have 62 00:03:09.439 --> 00:03:11.759 a Sagittarius, a star right in the middle of our 63 00:03:11.759 --> 00:03:12.560 own milky way. 64 00:03:12.599 --> 00:03:15.520 But they can't just grow infinitely fast, right Like. As 65 00:03:15.560 --> 00:03:18.479 matter spirals inward, it forms that accretion disk. 66 00:03:18.719 --> 00:03:22.960 Yeah, and viscous friction heats that material up to extreme temperatures. 67 00:03:23.000 --> 00:03:24.960 It emits intense radiation. 68 00:03:25.080 --> 00:03:28.439 And that radiation actually exerts outward pressure, doesn't it. Precisely 69 00:03:28.599 --> 00:03:30.240 it pushes back the Eddington limit. 70 00:03:30.560 --> 00:03:34.400 Yes, the Eddington limit. It's this physical threshold where the 71 00:03:34.439 --> 00:03:38.479 outward radiation pressure of that glowing disk perfectly balances the 72 00:03:38.520 --> 00:03:40.759 inward gravitational pull of the black hole. 73 00:03:41.120 --> 00:03:42.960 So it's essentially a speed limit for eating. 74 00:03:43.080 --> 00:03:45.120 That's a great way to put it. If the mass 75 00:03:45.120 --> 00:03:48.840 flowing in exceeds that Eddington limit, the radiation pressure just 76 00:03:48.960 --> 00:03:51.199 blows all the surrounding gas and dust away. 77 00:03:51.439 --> 00:03:51.759 Wow. 78 00:03:51.960 --> 00:03:54.719 Yeah, it completely cuts off the black hole's fuel supply. 79 00:03:55.120 --> 00:03:59.159 So it's an inherent self regulating mechanism. It strictly limits 80 00:03:59.159 --> 00:04:01.800 how fast ap black hole can grow just by pulling 81 00:04:01.840 --> 00:04:02.400 in gas. 82 00:04:02.960 --> 00:04:06.680 So if you calculate the maximum theoretical growth rate from 83 00:04:06.719 --> 00:04:10.520 a tiny stellar mass seed black hole up to a 84 00:04:10.599 --> 00:04:14.159 billion solar masses, keeping that speed limit in mind. 85 00:04:13.960 --> 00:04:15.680 The universe simply isn't old enough. 86 00:04:16.040 --> 00:04:18.519 It's just not It's like trying to explain how someone 87 00:04:18.759 --> 00:04:21.360 ate an entire elephant and realizing they couldn't possibly do 88 00:04:21.439 --> 00:04:22.959 it one bite at a time. They must have just 89 00:04:23.000 --> 00:04:24.480 absorbed another giant eater. 90 00:04:24.759 --> 00:04:29.199 Huh, exactly. The math absolutely requires a shortcut. You don't 91 00:04:29.199 --> 00:04:31.480 build a billion solar mass black hole by pulling in 92 00:04:31.560 --> 00:04:33.399 interstellar gas slowly over time. 93 00:04:33.639 --> 00:04:37.000 You build it by smashing two five hundred million solar 94 00:04:37.040 --> 00:04:38.079 mass black holes together. 95 00:04:38.439 --> 00:04:42.920 Right, hierarchical merging, which integrates perfectly with our models of 96 00:04:42.959 --> 00:04:47.199 how the universe is structure formed. Galaxies collide and merge 97 00:04:47.759 --> 00:04:48.160 all the. 98 00:04:48.160 --> 00:04:51.959 Time, and when they do, their central supermassive black holes 99 00:04:52.160 --> 00:04:53.680 are dragged along for the ride. 100 00:04:53.800 --> 00:04:57.199 Yeah, they're subjected to something called dynamical friction. They interact 101 00:04:57.240 --> 00:05:01.120 gravitationally with the surrounding sea of star and gas in 102 00:05:01.199 --> 00:05:02.879 the new, bigger galaxy. 103 00:05:02.959 --> 00:05:04.399 This sort of bounce around and lose energy. 104 00:05:04.519 --> 00:05:08.040 Basically, they transfer some of their orbital kinetic energy to 105 00:05:08.079 --> 00:05:11.319 the stars, flinging those stars outward, which means the black 106 00:05:11.319 --> 00:05:14.560 holes themselves lose energy. They sink toward the center and 107 00:05:14.639 --> 00:05:16.240 eventually form a binary pair. 108 00:05:16.600 --> 00:05:20.519 Okay, but if galaxy collisions are so commonplace, why has 109 00:05:20.560 --> 00:05:25.160 this final close pair phase completely eluded our detection until 110 00:05:25.199 --> 00:05:28.360 right now. What makes his final phase so impossible to see? 111 00:05:28.399 --> 00:05:30.959 Well, the theory hits a massive bottleneck right there. It's 112 00:05:30.959 --> 00:05:33.160 why finding the Murk five oh one binary is such 113 00:05:33.160 --> 00:05:37.600 a breakthrough. Dynamical friction works incredibly well at large distances. 114 00:05:37.879 --> 00:05:39.959 It brings the black holes from the outskirts down to 115 00:05:40.000 --> 00:05:42.560 the core. But once they get within about one parsec 116 00:05:42.600 --> 00:05:43.319 of each other. 117 00:05:43.360 --> 00:05:45.399 Which is roughly what three point two late. 118 00:05:45.360 --> 00:05:48.720 Years, yeah about that. Once they hit that one parsec distance, 119 00:05:49.120 --> 00:05:51.959 the mechanism just breaks down entirely. It's called the final 120 00:05:52.040 --> 00:05:53.279 parsec problem. 121 00:05:53.000 --> 00:05:54.000 The loss cone depletion. 122 00:05:54.199 --> 00:05:57.600 Right exactly, by the time they're that close, they've acted 123 00:05:57.639 --> 00:06:01.800 like a massive gravitational slingshot. They've ejected almost all the 124 00:06:01.839 --> 00:06:03.199 stars in their immediate vicinity. 125 00:06:03.360 --> 00:06:06.399 So the lost cone, the area where stars could intersect 126 00:06:06.399 --> 00:06:09.439 their orbit, it just empties out. 127 00:06:09.480 --> 00:06:13.079 It becomes completely barren, and without any more stars to 128 00:06:13.120 --> 00:06:15.519 interact with, the dynamical friction. 129 00:06:15.399 --> 00:06:18.199 Just stops, so the orbital of the case stalls out. 130 00:06:18.839 --> 00:06:19.519 They're stuck. 131 00:06:19.600 --> 00:06:23.680 They're completely stuck. Theoretically, they could just orbit each other indefinitely, 132 00:06:23.720 --> 00:06:27.040 separated by a single parsec, totally unable to close that 133 00:06:27.079 --> 00:06:29.519 final gap because there is nothing left to bleed off 134 00:06:29.519 --> 00:06:30.279 their momentum. 135 00:06:30.319 --> 00:06:33.800 Wow. So to overcome that final parsec you need something. 136 00:06:33.560 --> 00:06:37.040 Extreme right, either a massive influx of new gas to 137 00:06:37.079 --> 00:06:40.920 provide viscous drag like a wet merger, or a third 138 00:06:41.279 --> 00:06:44.319 super massive black hole crashing the party from a subsequent 139 00:06:44.360 --> 00:06:45.439 galactic collision, just. 140 00:06:45.360 --> 00:06:47.480 To destabilize things enough to get them closer. 141 00:06:47.879 --> 00:06:51.600 Yes, because only when they cross that final parsec threshold 142 00:06:51.839 --> 00:06:54.160 can they get close enough for gravitational wave emission to 143 00:06:54.160 --> 00:06:58.160 take over. That becomes the new primary way they lose energy, which. 144 00:06:57.959 --> 00:07:01.839 Really brings into focus why to detecting this system mcfive 145 00:07:01.879 --> 00:07:04.680 Oh one is just so profound. We aren't just looking 146 00:07:04.720 --> 00:07:06.759 at a binary system. We're looking at a system that 147 00:07:06.800 --> 00:07:11.399 has actually successfully navigated that final parsec problem exactly. 148 00:07:11.480 --> 00:07:14.199 It's past the bottleneck. It is deep into the gravitational 149 00:07:14.199 --> 00:07:15.199 wave emission regime. 150 00:07:15.399 --> 00:07:18.920 But seeing that requires cutting through the densest most chaotic 151 00:07:19.000 --> 00:07:22.639 regions of space. I mean, galactic cores are totally obscured 152 00:07:22.720 --> 00:07:26.680 by incredibly thick toruses of dust and gas. You can't 153 00:07:26.720 --> 00:07:28.160 just use a normal optical telescope. 154 00:07:28.240 --> 00:07:30.680 Now, optical wavelengths are entirely useless there, it's just a 155 00:07:30.680 --> 00:07:35.120 wall of dust. That is where very long baseline interferometry 156 00:07:35.199 --> 00:07:37.639 or VLBI becomes essential, right, And. 157 00:07:37.560 --> 00:07:39.720 This is where the team led by Silk Britsen at 158 00:07:39.720 --> 00:07:42.319 the Max Plank Institute for the Radio Astronomy comes in. 159 00:07:42.720 --> 00:07:45.879 They bypass the optical problem entirely by relying on high 160 00:07:45.920 --> 00:07:47.480 frequency radio observations. 161 00:07:47.839 --> 00:07:51.879 Yeah, because radio waves can penetrate that circumnuclear dust chorus 162 00:07:51.920 --> 00:07:55.399 without scattering too much. It lets us actually resolve the 163 00:07:55.439 --> 00:07:57.600 immediate environment of the black hole itself. 164 00:07:57.680 --> 00:08:01.480 And they specifically focused on the relativistic jets. Mag five 165 00:08:01.519 --> 00:08:03.680 oh one is classified as a blazer. 166 00:08:03.439 --> 00:08:06.680 Right, yes, which means its primary jet is oriented at 167 00:08:06.720 --> 00:08:09.639 an extremely narrow angle relative to our line of sight. 168 00:08:09.680 --> 00:08:11.120 It's basically pointing right at. 169 00:08:11.000 --> 00:08:13.800 Us, like staring down the barrel of a cosmic. 170 00:08:13.399 --> 00:08:17.759 Flashlight exactly, and the relativistic beaming or Doppler boosting makes 171 00:08:17.759 --> 00:08:20.639 the jet appear exceptionally bright because the plasma is moving 172 00:08:20.639 --> 00:08:22.920 toward us at a huge fraction of the speed of light. 173 00:08:23.319 --> 00:08:26.279 Okay, so tell me about the actual mechanics of these jets. 174 00:08:26.560 --> 00:08:30.319 Well. The Blanford's Nedjeck process driving those jets is critical. 175 00:08:30.319 --> 00:08:33.799 Here the supermassive black hole is rotating right, and that 176 00:08:33.919 --> 00:08:36.720 rotation actually twists the space time around it in the 177 00:08:36.840 --> 00:08:40.600 ergosphere right, and that twisting winds up the magnetic field 178 00:08:40.679 --> 00:08:43.840 lines threading through the accretion disc. It creates this immense 179 00:08:43.879 --> 00:08:45.399 magnetic tension. 180 00:08:45.120 --> 00:08:49.559 Which just violently accelerates plasma outward along the rotational axis. 181 00:08:49.720 --> 00:08:52.600 Boom, you get a jet and for decades. The VLBI 182 00:08:52.799 --> 00:08:55.879 data for MICK five oh one showed this really powerful, 183 00:08:56.279 --> 00:09:00.679 highly variable single jet structure, which is standard for a blazer. 184 00:09:01.120 --> 00:09:03.039 But the max Plank team didn't just look at a 185 00:09:03.039 --> 00:09:07.200 single snapshot. They utilized a twenty three year archive of 186 00:09:07.240 --> 00:09:09.000 this VLBI data. 187 00:09:08.720 --> 00:09:11.720 A twenty three year stare. They weren't just looking for 188 00:09:11.759 --> 00:09:15.559 a high resolution picture, they were looking for kinematic evolution 189 00:09:15.720 --> 00:09:16.919 over more than two decades. 190 00:09:17.039 --> 00:09:19.519 It's like watching a time lapse of a creeping glacier 191 00:09:19.879 --> 00:09:22.639 only to suddenly realize decades later that there are actually 192 00:09:22.639 --> 00:09:23.879 two glaciers moving together. 193 00:09:24.000 --> 00:09:27.240 That's a perfect analogy because within that massive twenty three 194 00:09:27.320 --> 00:09:30.440 year data set they isolated the signature of a second, 195 00:09:30.720 --> 00:09:32.200 entirely distinct jet. 196 00:09:32.279 --> 00:09:35.960 But wait, space is full of interference and radiation. VLBI 197 00:09:36.080 --> 00:09:39.919 data on blazers is notoriously messy. How do astronomers distinguish 198 00:09:39.960 --> 00:09:42.919 an entirely new second jet from just a I don't know, 199 00:09:42.919 --> 00:09:45.720 a burp, a flare, or some distortion in the primary 200 00:09:45.759 --> 00:09:46.759 jet we already knew about it. 201 00:09:46.720 --> 00:09:49.759 That's the million dollar question, because a knot of plasma 202 00:09:49.799 --> 00:09:52.399 moving down the primary jet or some instability in the 203 00:09:52.440 --> 00:09:55.200 flow can easily mimic a secondary structure. 204 00:09:55.360 --> 00:09:57.240 So how do you prove it's a second black hole 205 00:09:57.679 --> 00:09:59.480 and not just a glitch in the single jet? 206 00:10:00.200 --> 00:10:04.000 Rigorous kinematic proof. You have to look for sustained non 207 00:10:04.120 --> 00:10:07.759 radial motion. A plasma shock or a flare within a 208 00:10:07.759 --> 00:10:11.720 single jet will propagate outward generally following the established flow 209 00:10:11.759 --> 00:10:12.240 of the jet. 210 00:10:12.440 --> 00:10:14.919 Even if it expands or dissipates, it still moves down 211 00:10:14.960 --> 00:10:16.000 the same path. Right. 212 00:10:16.200 --> 00:10:18.519 But what the team observed in Mystic five oh one 213 00:10:18.559 --> 00:10:21.559 over those twenty three years was a secondary structure that 214 00:10:21.679 --> 00:10:26.080 originated behind the primary core emission, and it exhibited a distinct, 215 00:10:26.240 --> 00:10:28.840 repeating counterclockwise motion around it. 216 00:10:28.919 --> 00:10:30.399 Oh wow, so it was orbiting. 217 00:10:30.480 --> 00:10:33.840 The motion is the smoking gun. A localized instability does 218 00:10:33.879 --> 00:10:37.759 not establish a sustained orbital trajectory around the primary core. 219 00:10:37.960 --> 00:10:41.360 So the only physical mechanism capable of generating a secondary 220 00:10:41.720 --> 00:10:44.200 tightly beamed outflow that is actively. 221 00:10:43.879 --> 00:10:47.000 Orbiting is a second super massive black hole, one that 222 00:10:47.080 --> 00:10:50.600 is actively a creating matter and powering its own independent jet. 223 00:10:50.799 --> 00:10:53.240 That is just mind blowing. And the realization that this 224 00:10:53.320 --> 00:10:55.679 second jet was moving like that, it opens up this 225 00:10:55.799 --> 00:10:59.080 wild new reality about the whole system. The entire galactic 226 00:10:59.120 --> 00:11:01.279 core of Markurrian five on one is in a state 227 00:11:01.320 --> 00:11:04.360 of chaotic motion. Yeah. The presence of the second jet 228 00:11:04.440 --> 00:11:07.440 also provides the framework for understanding the larger anomalies in 229 00:11:07.480 --> 00:11:12.159 the system. The entire primary jet structure exhibits this pronounced 230 00:11:12.200 --> 00:11:13.000 swaying motion. 231 00:11:13.360 --> 00:11:17.559 Silk Britsen compared evaluating the data to being on a 232 00:11:17.600 --> 00:11:20.200 moving ship. The entire system is precessing. 233 00:11:20.360 --> 00:11:24.559 Yes, the orbital plane of the binary is essentially wobbling. 234 00:11:24.200 --> 00:11:26.360 Because if you have two super massive bodies in a 235 00:11:26.399 --> 00:11:31.279 tight orbit, their individual spins and their orbital angular momentum 236 00:11:31.320 --> 00:11:32.679 are constantly interacting. 237 00:11:32.759 --> 00:11:36.919 Frame dragging, the lens thiring effect becomes incredibly pronounced at 238 00:11:36.919 --> 00:11:40.639 these masses in proximity. The rotating masses literally drag the 239 00:11:40.639 --> 00:11:42.600 local fabric of space time along with. 240 00:11:42.559 --> 00:11:45.120 Them, twisting the orientation of the accretion disks and the 241 00:11:45.159 --> 00:11:46.240 jets they produce. 242 00:11:46.120 --> 00:11:49.039 Exactly, so the angle of those jets relative to Earth 243 00:11:49.159 --> 00:11:52.960 is in a state of continuous predictable change. The sweeping 244 00:11:52.960 --> 00:11:55.000 motion alters the beaming effects. 245 00:11:54.720 --> 00:11:57.919 We observe, and this wobbling, this processing geometry, is what 246 00:11:58.000 --> 00:12:00.600 ultimately led to that massive event in June of twenty 247 00:12:00.679 --> 00:12:02.120 twenty two, the Einstein ring. 248 00:12:02.240 --> 00:12:05.559 Yes, gravitational lensing in action. Break that down for me, 249 00:12:05.639 --> 00:12:10.000 because the physics gravitational lensing are just wild. It happens 250 00:12:10.039 --> 00:12:13.600 when a massive four ground object warps the space time 251 00:12:13.639 --> 00:12:16.399 around it, bending the pass of light from a background 252 00:12:16.440 --> 00:12:17.519 source right right. 253 00:12:17.799 --> 00:12:20.960 But the specific alignment required to produce a complete ring 254 00:12:21.399 --> 00:12:24.840 rather than just an arc or multiple blurry images, requires 255 00:12:24.879 --> 00:12:27.799 an almost mathematically perfect sizogy. 256 00:12:27.440 --> 00:12:31.200 A perfect alignment between the observer us, the lens and. 257 00:12:31.120 --> 00:12:34.039 The source precisely. It relies on the impact parameter and 258 00:12:34.080 --> 00:12:37.799 the specific orientation. So in June twenty twenty two, the 259 00:12:37.840 --> 00:12:41.759 precession of the binary system brought the primary more massive 260 00:12:41.759 --> 00:12:45.240 black hole directly across our line of sight to the 261 00:12:45.279 --> 00:12:46.559 base of the secondary jet. 262 00:12:46.679 --> 00:12:49.679 Wow. So the primary black hole acted as the gravitational 263 00:12:49.759 --> 00:12:51.519 lens for the second black hole's jet. 264 00:12:51.639 --> 00:12:55.440 Yes, Because the alignment was so precise, the radio emissions 265 00:12:55.440 --> 00:12:58.279 from the secondary jet passing through the primari's gravitational well 266 00:12:58.440 --> 00:13:00.320 were deflected equally in all directs. 267 00:13:00.399 --> 00:13:02.639 It's like looking at a candle flame through the thick 268 00:13:02.679 --> 00:13:05.559 base of a wineglass. The glass bends the light into 269 00:13:05.559 --> 00:13:09.200 a complete circle. But here the wineglass is a supermassive 270 00:13:09.240 --> 00:13:09.759 black hole. 271 00:13:10.000 --> 00:13:12.879 That's exactly what it looks like. The warped space time 272 00:13:13.000 --> 00:13:17.600 stretched that emission into a perfect closed circular contour around 273 00:13:17.639 --> 00:13:21.679 the primary black hole's position, a tangential caustic Well. 274 00:13:21.720 --> 00:13:24.120 Let me ask you this, does this kind of perfect 275 00:13:24.320 --> 00:13:27.559 ring forming alignment happen on a regular schedule due to 276 00:13:27.600 --> 00:13:30.600 the orbit or was June twenty twenty two just a 277 00:13:30.679 --> 00:13:33.759 moment of incredibly lucky cosmic timing for us? 278 00:13:33.960 --> 00:13:36.840 Well, because of the procession, it is a transient alignment, 279 00:13:36.879 --> 00:13:39.279 so catching it in a twenty three year window is 280 00:13:39.320 --> 00:13:43.159 an incredibly rare observational triumph. It's a huge stroke of luck, 281 00:13:43.480 --> 00:13:46.120 but it's also a testament to just continuously watching the 282 00:13:46.159 --> 00:13:46.960 system and. 283 00:13:46.960 --> 00:13:49.320 Catching that ring wasn't just for a cool picture, right, 284 00:13:49.639 --> 00:13:53.759 It provided direct geometric conformation of the mass distribution and 285 00:13:53.799 --> 00:13:55.399 the separation of the two black. 286 00:13:55.159 --> 00:13:58.639 Holes exactly the radius of the Einstein ring. The Einstein 287 00:13:58.720 --> 00:14:02.120 radius is direct proportional to the square root of the 288 00:14:02.159 --> 00:14:03.559 mass of the lensing object. 289 00:14:03.799 --> 00:14:06.440 So by measuring the angular size of the ring and 290 00:14:06.480 --> 00:14:08.679 combining it with the data from the twenty three year 291 00:14:08.759 --> 00:14:12.480 VLBI study, they could finally lock down the orbital parameters 292 00:14:12.519 --> 00:14:13.440 of the binary. 293 00:14:13.159 --> 00:14:17.000 With unprecedented precision, and the numbers they derived are just staggering. 294 00:14:17.279 --> 00:14:20.600 Let's get into those numbers the final countdown, because the 295 00:14:20.720 --> 00:14:23.159 orbital period they calculated is just one hundred and twenty 296 00:14:23.159 --> 00:14:23.919 one days. 297 00:14:23.639 --> 00:14:27.559 Which is incredibly fast, and the physical separation between the 298 00:14:27.559 --> 00:14:30.799 two supermassive black holes is calculated to be between two 299 00:14:30.919 --> 00:14:34.519 hundred and fifty and five hundred and forty astronomical units. 300 00:14:34.759 --> 00:14:37.440 Wait, two hundred and fifty to five hundred and forty AU. 301 00:14:37.840 --> 00:14:39.720 I mean that sounds like a big number, but for 302 00:14:39.799 --> 00:14:43.200 objects weighing hundreds of millions or billions of solar masses, 303 00:14:43.279 --> 00:14:44.840 that is terrifyingly close. 304 00:14:45.080 --> 00:14:48.759 It places them deep into the strongly relativistic regime. I mean, 305 00:14:48.759 --> 00:14:51.639 the actual physical size of the black holes, their schwartz 306 00:14:51.720 --> 00:14:55.000 Child radioccupy significant fraction of that space. 307 00:14:54.720 --> 00:14:57.120 For scale two hundred and fifty AU is roughly six 308 00:14:57.200 --> 00:14:59.000 times the distance from our Sun to Pluto. 309 00:14:59.159 --> 00:15:01.440 Yeah, that's practical. Touching in galactic. 310 00:15:01.080 --> 00:15:03.080 Terms, in one hundred and twenty one days is basically 311 00:15:03.080 --> 00:15:06.600 a semester of college, and these billion sun mass objects 312 00:15:06.639 --> 00:15:09.519 are completing a full lap in that time. The gravitational 313 00:15:09.519 --> 00:15:11.360 forces at play are unimaginable. 314 00:15:11.440 --> 00:15:13.840 For objects of this mass to complete an entire orbital 315 00:15:13.879 --> 00:15:16.279 circuit in just four months, they have to be moving 316 00:15:16.279 --> 00:15:18.080 at a significant fraction of the speed of light. 317 00:15:18.320 --> 00:15:20.720 The sheer kinetic energy driving that one hundred and twenty 318 00:15:20.720 --> 00:15:24.879 one day orbit dictates an incredibly aggressive rate of orbital decay, doesn't. 319 00:15:24.600 --> 00:15:28.000 It It does. The system is governed by Peter's equations 320 00:15:28.000 --> 00:15:31.519 for gravitational radiation. Now it's shedding massive amounts of orbital 321 00:15:31.600 --> 00:15:36.600 energy and angular momentum by radiating low frequency gravitational waves, and. 322 00:15:36.519 --> 00:15:39.759 The decay rate accelerates exponentially as they draw closer. 323 00:15:39.919 --> 00:15:43.600 Right, the power radio by gravitational waves is inversely proportional 324 00:15:43.639 --> 00:15:46.679 to the fifth power of the orbital separation, so the 325 00:15:46.679 --> 00:15:48.519 closer they get, the faster they fall. 326 00:15:48.320 --> 00:15:51.440 In, which brings us to the timeline because the calculations 327 00:15:51.480 --> 00:15:55.919 placed the final coalescence of these two behemoths within approximately 328 00:15:56.080 --> 00:15:56.879 one hundred. 329 00:15:56.600 --> 00:15:59.159 Years, just one hundred years. We are not looking at 330 00:15:59.200 --> 00:16:02.879 a merger on some vague cosmological time scale. We are 331 00:16:02.879 --> 00:16:07.360 looking at an event that will occur within a human generational. 332 00:16:06.639 --> 00:16:08.799 Timeframe god'smc microsecond. 333 00:16:08.360 --> 00:16:11.879 Exactly, and the steepness of that inspiral curve over the 334 00:16:11.919 --> 00:16:14.559 next century is going to be profound. The orbit will 335 00:16:14.600 --> 00:16:17.559 continue to shrink, the period will drop from one hundred 336 00:16:17.559 --> 00:16:20.039 and twenty one days down to weeks, then. 337 00:16:20.080 --> 00:16:23.240 Days, until the event horizons finally intersect and just ring 338 00:16:23.320 --> 00:16:26.759 down into a single newly formed black hole. Okay, So 339 00:16:27.480 --> 00:16:29.799 if they are that close and moving that fast and 340 00:16:29.799 --> 00:16:32.679 give an emerge one hundred years, why can't we just 341 00:16:32.720 --> 00:16:35.240 point to the biggest telescope we have at hercules and 342 00:16:35.320 --> 00:16:36.279 watch them crash. 343 00:16:36.480 --> 00:16:40.840 And that is the ultimate frustration of observational astrophysics. Right there, 344 00:16:41.200 --> 00:16:43.759 the system is four hundred and fifty six million light 345 00:16:43.840 --> 00:16:47.679 years away. Right at that distance, an orbital separation of 346 00:16:47.679 --> 00:16:50.919 two fifty to five hundred and forty au translates to 347 00:16:50.960 --> 00:16:54.120 an angular resolution requirement on the order of microorc seconds, 348 00:16:54.120 --> 00:16:56.600 which is too small way too small. Even the event 349 00:16:56.679 --> 00:16:59.960 horizon telescope, which famously imaged black holes in twenty nineteen. 350 00:17:00.080 --> 00:17:03.120 In twenty twenty two, it operates in the tens of 351 00:17:03.159 --> 00:17:03.799 micro arc. 352 00:17:03.759 --> 00:17:05.839 Seconds, so it's just a hard physical wall. 353 00:17:06.000 --> 00:17:09.920 The physical Railey criterion prevents us from ever optically or 354 00:17:10.079 --> 00:17:14.039 radiometrically resolving the two distinct event horizons right before impact. 355 00:17:13.759 --> 00:17:17.119 So the actual physical merger will remain visually unresolved. A 356 00:17:17.160 --> 00:17:19.839 single point of intense radio and X ray emission is 357 00:17:19.880 --> 00:17:21.599 all our telescopes are ever going to capture. 358 00:17:21.720 --> 00:17:24.599 Yeah, but that inability to see them as two separate 359 00:17:24.640 --> 00:17:27.839 objects is precisely why Murk five oh one is fundamentally 360 00:17:27.920 --> 00:17:33.079 shifting our observational paradigm. We are moving toward continuous gravitational wave. 361 00:17:32.880 --> 00:17:37.079 Astronomy invisible ripples. We essentially have to trade our eyes 362 00:17:37.160 --> 00:17:37.880 for our ears. 363 00:17:38.000 --> 00:17:39.400 That's exactly what we have. 364 00:17:39.359 --> 00:17:41.359 To do, because we won't be able to see the 365 00:17:41.400 --> 00:17:44.640 splash of the collision, but we will absolutely feel the 366 00:17:44.720 --> 00:17:45.880 ripples hitting the shore. 367 00:17:46.160 --> 00:17:50.680 Right, we have to move past the electromagnetic spectrum entirely. Now. 368 00:17:50.839 --> 00:17:55.079 Ligo and Virgo have revolutionized astrophysics by detecting high frequency 369 00:17:55.160 --> 00:17:57.960 gravitational waves from stellar mass black holes. 370 00:17:58.480 --> 00:18:01.720 But a supermassive binary on one hundred and twenty one 371 00:18:01.799 --> 00:18:05.039 day orbit operates at a vastly different frequency right. 372 00:18:05.000 --> 00:18:08.039 A completely different scale. The wave frequency is basically twice 373 00:18:08.079 --> 00:18:10.839 the orbital frequency. So for a one hundred and twenty 374 00:18:10.880 --> 00:18:13.960 one day orbit, we're dealing with gravitational waves in the 375 00:18:14.039 --> 00:18:15.400 Nanohurtz regime. 376 00:18:15.279 --> 00:18:18.880 Meaning the physical wavelengths of these gravity ripples span light years. 377 00:18:19.000 --> 00:18:23.359 Yes, ground based interferometers like Lego are entirely blind to 378 00:18:23.400 --> 00:18:27.279 these frequencies. To detect nanohertz gravitational waves, you need a 379 00:18:27.319 --> 00:18:29.880 detector baseline on a galactic scale. 380 00:18:29.559 --> 00:18:32.119 Which sounds like science fiction, but we actually have one 381 00:18:32.319 --> 00:18:33.599 pulsar timing arrays. 382 00:18:33.680 --> 00:18:38.039 The European Pulsar Timing Array NANOGrav and the Park's array explain. 383 00:18:37.680 --> 00:18:40.640 How a pulsar timing array actually works as a detector. 384 00:18:41.440 --> 00:18:44.400 How do scientists use the steady ticking of dead stars 385 00:18:44.839 --> 00:18:46.480 to feel gravity warping. 386 00:18:47.200 --> 00:18:51.880 It's brilliant, really. The methodology relies on millisecond pulsars. These 387 00:18:51.880 --> 00:18:54.599 are ultra dense neutron stars that have been spun up 388 00:18:54.599 --> 00:18:56.799 by a creating material from a companion. 389 00:18:56.440 --> 00:18:58.319 Star, so they spin incredibly fast. 390 00:18:58.680 --> 00:19:02.559 Rotational periods on the order of milliseconds, and because they 391 00:19:02.559 --> 00:19:06.680 have this immense moment of inertia, their rotation is incredibly stable. 392 00:19:07.119 --> 00:19:10.599 They function as highly precise celestial clocks, and. 393 00:19:10.559 --> 00:19:13.920 We can model their radio pulses down to the nanosecond exactly. 394 00:19:14.319 --> 00:19:18.839 We account for incredibly complex variables, including the interstellar medium 395 00:19:18.880 --> 00:19:21.480 and the proper motion of the pulsars themselves. We know 396 00:19:21.559 --> 00:19:24.240 exactly when a pulse should hit our telescopes on Earth. 397 00:19:24.440 --> 00:19:27.599 So what happens when a nanohurtz gravitational wave rolls through. 398 00:19:27.519 --> 00:19:30.400 It repropagates through the local space time between Earth and 399 00:19:30.440 --> 00:19:34.680 that monitored millisecond pulsar. It physically perturbs the space time metric. 400 00:19:34.960 --> 00:19:37.839 It alters the geodesic path the radiopulse has to travel. 401 00:19:37.920 --> 00:19:39.880