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 00:00:26.960 --> 00:00:30.359 Imagine you're standing outside on a perfectly clear night. 8 00:00:30.440 --> 00:00:31.839 Oh that sounds nice, right. 9 00:00:32.119 --> 00:00:34.600 You're far away from the city, no street lights, no 10 00:00:34.719 --> 00:00:37.880 light pollution at all. You were just staring up at 11 00:00:37.880 --> 00:00:40.880 a completely dark, quiet patch of the night sky, just 12 00:00:41.000 --> 00:00:44.240 you and the universe exactly. The stars are fixed. Everything 13 00:00:44.280 --> 00:00:50.640 seems peaceful, serene, ancient. But then suddenly, right in the 14 00:00:50.640 --> 00:00:55.679 middle of that black void, there's this brilliant, blindingly powerful 15 00:00:56.039 --> 00:00:59.520 double flash of energy out of nowhere, out of nowhere, 16 00:00:59.600 --> 00:01:03.679 It's up that patch of space with unimaginable violence, and then, 17 00:01:04.000 --> 00:01:08.239 almost as quickly as it appeared, it just vanishes, complete silence. Again. 18 00:01:08.280 --> 00:01:11.040 Here's the crazy part, though. If you were standing there, 19 00:01:11.159 --> 00:01:14.480 relying entirely on your own human eyes, you wouldn't have 20 00:01:14.519 --> 00:01:16.959 seen a single thing, nothing at all, not a blip 21 00:01:17.000 --> 00:01:20.319 the sky would have remained completely unchanged because well, human 22 00:01:20.400 --> 00:01:23.599 vision is locked into this ridiculously narrow band of the 23 00:01:23.640 --> 00:01:26.359 electromagnetic spectrum. We just see visible. 24 00:01:26.079 --> 00:01:27.719 Light, right the colors of the rainbow. 25 00:01:27.840 --> 00:01:30.040 Yeah, exactly, But the universe, I mean, it doesn't limit 26 00:01:30.040 --> 00:01:32.159 its violence to the colors of the rainbow. 27 00:01:31.920 --> 00:01:35.599 Which is terrifying honestly, but fascinating at the same time, 28 00:01:36.159 --> 00:01:40.719 because this flash absolutely happened. It was completely invisible to 29 00:01:40.760 --> 00:01:43.560 the naked eye, but it happened, and it left the 30 00:01:43.560 --> 00:01:46.840 smartest astronomers on Earth completely scratching their heads. 31 00:01:46.959 --> 00:01:48.200 Oh, totally baffles. 32 00:01:48.280 --> 00:01:51.159 We're talking about an event that occurred recently on March fifth, 33 00:01:51.239 --> 00:01:54.239 twenty twenty four, and to really figure out what happened 34 00:01:54.239 --> 00:01:56.280 out there in the dark, we've got to look at 35 00:01:56.280 --> 00:02:00.920 the initial alert logs, the multi wavelength follow up data 36 00:02:00.920 --> 00:02:05.439 from all over the planet, and well the theoretical astrophysics 37 00:02:05.480 --> 00:02:07.040 trying to piece this whole puzzle together. 38 00:02:07.120 --> 00:02:09.599 It's a massive puzzle, it really is, and it. 39 00:02:09.520 --> 00:02:13.159 All starts with a highly sensitive piece of orbital technology 40 00:02:13.199 --> 00:02:14.680 called the Einstein Probe. 41 00:02:14.719 --> 00:02:17.960 The Einstein Probe is just it's an incredible feat of engineering. 42 00:02:18.080 --> 00:02:21.759 It's a space telescope launched with a very specific and 43 00:02:21.840 --> 00:02:26.240 frankly very difficult mission, which of what basically to tirelessly 44 00:02:26.319 --> 00:02:28.919 stare into the cosmic abyss and just wait for something 45 00:02:28.919 --> 00:02:31.280 to explode. But like we said, it doesn't look for 46 00:02:31.400 --> 00:02:34.800 visible light. It's equipped with these wide field X ray optics. 47 00:02:34.840 --> 00:02:38.719 They call them lobster eye optics, right, yeah. 48 00:02:37.960 --> 00:02:40.479 It's super cool. It mimics the way a crustacean's eye 49 00:02:40.520 --> 00:02:42.719 can take in light from a massive field of view 50 00:02:42.759 --> 00:02:45.120 all at once. So it just scans the cosmos for 51 00:02:45.199 --> 00:02:48.439 these sudden, totally unpredictable, high energy. 52 00:02:48.240 --> 00:02:49.120 X ray flashes. 53 00:02:49.280 --> 00:02:51.520 And it has to be in space because our atmosphere 54 00:02:51.560 --> 00:02:54.680 actually protects us from X rays. If the Einstein probe 55 00:02:54.759 --> 00:02:58.560 was sitting on a mountain on Earth, it wouldn't see anything. 56 00:02:58.680 --> 00:03:02.159 That is a crucial point. The Earth's atmosphere is incredibly thick. 57 00:03:02.319 --> 00:03:05.000 It acts like a lead shield against high energy radiation 58 00:03:05.159 --> 00:03:06.599 like X rays and gamma rays. 59 00:03:06.400 --> 00:03:07.240 Which is great for us. 60 00:03:07.319 --> 00:03:10.919 Oh yeah. If our atmosphere didn't absorb those wavelengths, life 61 00:03:10.960 --> 00:03:13.960 on Earth would be sterilized. Period. So to observe the 62 00:03:14.000 --> 00:03:16.639 high energy universe, we literally have to put our robotic 63 00:03:16.680 --> 00:03:18.039 eyes above the atmosphere. 64 00:03:18.199 --> 00:03:21.080 Makes sense. So on this day in March, this orbital 65 00:03:21.080 --> 00:03:24.199 telescope is just doing its job, watching the dark, and 66 00:03:24.240 --> 00:03:26.240 it catches something entirely. 67 00:03:25.800 --> 00:03:27.759 New, a completely novel event. 68 00:03:27.680 --> 00:03:31.000 Right, and it gets cataloged with the incredibly poetic name 69 00:03:31.120 --> 00:03:34.000 of EP two four zero three zero five. 70 00:03:34.039 --> 00:03:36.680 A ah, yes, the romance of astronomy. 71 00:03:36.879 --> 00:03:39.400 I know they love their naming conventions. Yeah, but essentially 72 00:03:39.400 --> 00:03:42.879 that just stands for Einstein probe, the year twenty twenty four, 73 00:03:43.240 --> 00:03:45.439 the month of March, the fifth day, and the first 74 00:03:45.439 --> 00:03:46.120 event of the day. 75 00:03:46.639 --> 00:03:50.840 It's pure functional data management. But you know, the name 76 00:03:50.919 --> 00:03:52.080 isn't really the point. 77 00:03:52.240 --> 00:03:56.199 No, The core mystery here is that this specific flash 78 00:03:56.240 --> 00:04:01.280 of X rays completely defies existing classification. It doesn't fit 79 00:04:01.319 --> 00:04:02.280 into any known. 80 00:04:02.120 --> 00:04:03.680 Box, not a single one. 81 00:04:03.759 --> 00:04:06.520 If we're playing cosmic detective, it's sort of like it's 82 00:04:06.560 --> 00:04:09.120 like finding an animal in the woods that has the 83 00:04:09.159 --> 00:04:11.479 feathers of a bird, the scales of a fish, and 84 00:04:11.520 --> 00:04:12.360 the bark of a dog. 85 00:04:12.639 --> 00:04:14.800 That's a great way to put it. The physical mechanics 86 00:04:14.800 --> 00:04:17.240 of what we're looking at just don't align with the 87 00:04:17.279 --> 00:04:19.560 categories we've spent centuries building. 88 00:04:19.480 --> 00:04:22.040 And astrophysics relies on those categories completely. 89 00:04:22.199 --> 00:04:24.879 The universe is usually quite good at fitting into our 90 00:04:25.000 --> 00:04:28.319 established models. We know the exact signature of a dying star. 91 00:04:28.879 --> 00:04:32.120 We know the signature of a supermassive black hole feeding 92 00:04:32.160 --> 00:04:33.199 on a cloud of gas. 93 00:04:33.439 --> 00:04:35.240 So when something doesn't fit, when. 94 00:04:35.120 --> 00:04:38.680 A transient event entirely refuses to fit into those boxes, 95 00:04:38.800 --> 00:04:42.319 it forces a reckoning. It means our understanding of the 96 00:04:42.360 --> 00:04:45.879 fundamental mechanics of extreme stellar death is incomplete. 97 00:04:45.959 --> 00:04:49.079 To understand why this event is forcing that reckoning, we 98 00:04:49.160 --> 00:04:51.839 need to look really really closely at the precise timeline 99 00:04:51.839 --> 00:04:55.120 of the flash, because it wasn't just a random burst 100 00:04:55.120 --> 00:04:55.639 of static. 101 00:04:55.839 --> 00:04:59.759 No, it had a highly specific and frankly very weird heartbeat. 102 00:05:00.120 --> 00:05:03.480 Right the Einstein probe witnessed a brief X ray flare, 103 00:05:04.199 --> 00:05:06.360 a massive spike of energy, and then this is the 104 00:05:06.399 --> 00:05:09.240 wild part. The energy dropped to nothing, dead quiet, yeah, 105 00:05:09.360 --> 00:05:11.759 for about two hundred seconds, and then boom, a second 106 00:05:11.800 --> 00:05:13.480 brief X ray flare hit right after it. 107 00:05:13.560 --> 00:05:16.720 In the realm of transient astronomy, which focuses entirely on 108 00:05:16.800 --> 00:05:19.600 things that change rapidly in the sky, a two hundred 109 00:05:19.639 --> 00:05:21.879 second pause is deeply anomalous. 110 00:05:21.920 --> 00:05:24.759 It feels anomalous just logically. I mean, when I picture 111 00:05:24.759 --> 00:05:28.959 a cosmic explosion. I picture a singular catastrophic release of energy. 112 00:05:29.120 --> 00:05:31.279 A star blows up, it expands. 113 00:05:30.839 --> 00:05:32.360 Outwards, a one and done kind of deal. 114 00:05:32.639 --> 00:05:34.959 Exactly. A star doesn't blow up, pause for three and 115 00:05:34.959 --> 00:05:36.560 a half minutes to catch its brapp and then blow 116 00:05:36.639 --> 00:05:38.240 up a second time. It makes me think of an 117 00:05:38.279 --> 00:05:39.000 engine stalling. 118 00:05:39.279 --> 00:05:41.000 An engine stalling, Yeah, like an. 119 00:05:40.920 --> 00:05:45.279 Old car engine that vapor locks, It sputters, goes completely 120 00:05:45.319 --> 00:05:48.519 silent while the fuel line clears, and then aggressively fires 121 00:05:48.560 --> 00:05:52.360 one last time. Does the universe actually build engines that 122 00:05:52.439 --> 00:05:52.920 can stall? 123 00:05:53.319 --> 00:05:55.759 You know that analogy of a stalling engine is actually 124 00:05:55.800 --> 00:05:58.759 incredibly close to the underlying physics we're talking about here. Really, 125 00:05:58.879 --> 00:06:02.519 oh absolutely. If we look at standard cosmic explosions, like 126 00:06:02.519 --> 00:06:07.279 a supernova, that is a continuous outward expansion of energy 127 00:06:07.439 --> 00:06:10.959 and matter, it rises in brightness, it peaks, and it 128 00:06:11.040 --> 00:06:12.759 fades over weeks. 129 00:06:12.519 --> 00:06:14.519 Right, a single structural failure, but. 130 00:06:14.519 --> 00:06:17.959 A double flare separated by a hard pause. That implies 131 00:06:17.959 --> 00:06:21.040 a central engine that is actively managing a flow of fuel. 132 00:06:21.319 --> 00:06:23.240 So we aren't looking at a bomb going off. We're 133 00:06:23.240 --> 00:06:25.199 looking at a machine processing material. 134 00:06:25.439 --> 00:06:29.040 Exactly. The machine in this context is almost certainly a 135 00:06:29.040 --> 00:06:32.800 black hole, or maybe a highly magnetized neutron star, and 136 00:06:32.839 --> 00:06:34.519 the fuel is an accretion disk. 137 00:06:34.600 --> 00:06:38.439 An accretion disc, that's the swirling vortex of superheated gas 138 00:06:38.480 --> 00:06:40.480 spiraling down into the gravitational Well. 139 00:06:40.439 --> 00:06:40.920 We got it. 140 00:06:41.160 --> 00:06:44.240 Black holes do not function like cosmic vacuum cleaners. They're 141 00:06:44.240 --> 00:06:45.839 more like a massive traffic jam. 142 00:06:46.040 --> 00:06:46.800 A traffic jam. 143 00:06:46.959 --> 00:06:49.560 Yeah, material is trying to fall in, but it's spinning 144 00:06:49.680 --> 00:06:53.639 so fast that centrifugal force fights against gravity, so it literally. 145 00:06:53.399 --> 00:06:55.399 Has to wait its turned across the event horizon. 146 00:06:55.519 --> 00:07:00.160 Yes, the gas rubs against itself, creating immense friction and 147 00:07:00.240 --> 00:07:03.560 heating up to millions of degrees, which, by the way, 148 00:07:03.600 --> 00:07:05.120 is what produces the X rayce. 149 00:07:05.199 --> 00:07:07.399 Okay, so that's the flare. But where does the pause 150 00:07:07.399 --> 00:07:07.680 come in. 151 00:07:07.839 --> 00:07:11.879 Well, accretion disks are highly unstable. They're governed by super 152 00:07:11.920 --> 00:07:15.879 complex magnetic fields. If those magnetic fields get tangled up, 153 00:07:16.040 --> 00:07:18.959 or if a massive clump of matter temporarily blocks the 154 00:07:19.000 --> 00:07:23.079 inner flow, the engine can effectively choke. Wow, the flow 155 00:07:23.120 --> 00:07:25.560 of fuel into the black hole stops, the X ray 156 00:07:25.600 --> 00:07:28.639 emission shuts off, and that is your two hundred second. 157 00:07:28.360 --> 00:07:29.639 Pause, and then it clears. 158 00:07:29.879 --> 00:07:33.879 Yep, the magnetic tension snaps, the blockage clears, a new 159 00:07:33.920 --> 00:07:37.439 clump of matter falls in, and the engine aggressively reignites, 160 00:07:37.560 --> 00:07:39.000 producing that second flare. 161 00:07:39.360 --> 00:07:41.920 So a black hole basically choked on its dinner, had 162 00:07:41.920 --> 00:07:44.120 a three minute coughing fit, and then took a second bite. 163 00:07:44.160 --> 00:07:47.279 That is a very visceral, but very accurate way to 164 00:07:47.360 --> 00:07:47.879 describe it. 165 00:07:48.199 --> 00:07:51.360 But here is the massive logistical problem with studying an 166 00:07:51.399 --> 00:07:54.600 event like this. You don't get a calendar invite. Never 167 00:07:54.720 --> 00:07:58.079 we know years in advance exactly when a solar eclipse 168 00:07:58.120 --> 00:08:00.560 is going to happen, down to the millisecond, but a 169 00:08:00.639 --> 00:08:03.800 transient X ray flash. By the time the Einstein probe's 170 00:08:03.800 --> 00:08:06.680 alarm bells start ringing down here on Earth, the event 171 00:08:06.759 --> 00:08:07.519 is completely over. 172 00:08:08.160 --> 00:08:12.199 That is the fundamental hair pulling frustration of transient astronomy. 173 00:08:12.240 --> 00:08:16.199 You are entirely at the mercy of the universe's unpredictability. 174 00:08:16.279 --> 00:08:18.319 It's all reacting, completely reactive. 175 00:08:18.680 --> 00:08:22.399 These sudden flashes are the ultimate fleeting evidence. By the 176 00:08:22.399 --> 00:08:26.120 time the orbital telescope registers the photons, processes the data, 177 00:08:26.399 --> 00:08:29.759 and beams an alert down to ground control, the primary 178 00:08:29.839 --> 00:08:33.039 signal the X rays generated by that immediate violence, is 179 00:08:33.159 --> 00:08:35.159 already dissipating into the void. 180 00:08:35.120 --> 00:08:38.039 Which means catching the initial flash is really only step 181 00:08:38.080 --> 00:08:41.919 one of the investigation. The actual science, the real detective work, 182 00:08:42.279 --> 00:08:46.639 happens in the frantic, highly coordinated scramble immediately after the flash. 183 00:08:46.799 --> 00:08:49.159 Right, how do you study an explosion when the fire 184 00:08:49.200 --> 00:08:50.080 is already dying out? 185 00:08:50.360 --> 00:08:54.399 Exactly? You have to mobilize every available observatory on Earth 186 00:08:54.480 --> 00:08:57.600 and in space as fast as humanly possible before the 187 00:08:57.639 --> 00:09:03.000 ashes blow away. That introduces the necessity of what astronomers 188 00:09:03.039 --> 00:09:06.600 call a massive multi wavelength follow up campaign. 189 00:09:06.840 --> 00:09:09.759 This is where the story turns into an international scavenger hunt. 190 00:09:09.879 --> 00:09:12.600 Once the Einstein probe sounded the alarm on EP two 191 00:09:12.679 --> 00:09:16.279 forty three oh five, A, researchers rapidly pointed multiple different 192 00:09:16.320 --> 00:09:19.679 telescopes located all over the globe and in orbit at 193 00:09:19.720 --> 00:09:21.360 those exact coordinates in the sky. 194 00:09:21.519 --> 00:09:23.840 And they didn't just look for more X rays. They 195 00:09:23.919 --> 00:09:28.080 gather data across entirely different wavelengths of the electromagnetic spectrum. 196 00:09:28.159 --> 00:09:31.600 We're talking X rays, infrared, optical, and radio. 197 00:09:32.159 --> 00:09:35.480 This is critical for anyone trying to understand the modern astronomy. 198 00:09:35.759 --> 00:09:38.679 We aren't just looking through glass lenses trying to magnify 199 00:09:38.759 --> 00:09:40.120 visible light anymore, not at all. 200 00:09:40.240 --> 00:09:43.200 The universe communicates across an entire spectrum. If you only 201 00:09:43.240 --> 00:09:45.480 look at the visible light, you're only reading one single 202 00:09:45.519 --> 00:09:47.639 paragraph of a massive encyclopedia. 203 00:09:47.799 --> 00:09:49.799 For anyone listening who might not be a physicist. I 204 00:09:49.799 --> 00:09:52.480 want to make sure the concept of wavelengths really lands 205 00:09:52.840 --> 00:09:56.159 because it is the absolute key to unraveling everything that follows. 206 00:09:56.480 --> 00:09:58.279 It's the most important concept here. 207 00:09:58.360 --> 00:10:00.519 Think of it like a car crash. I'm standing on 208 00:10:00.519 --> 00:10:04.960 the sidewalk and I witness two cars collide. My eyes, 209 00:10:05.240 --> 00:10:09.559 which are basically biological optical sensors, see the dented metal, 210 00:10:09.679 --> 00:10:12.600 the shattered glass, the red paint of the car. That 211 00:10:12.720 --> 00:10:15.039 is optical data, right. But if I pull out a 212 00:10:15.039 --> 00:10:19.440 thermal infrared camera, I don't see the red paint anymore. Instead, 213 00:10:19.519 --> 00:10:22.600 I see the intense glowing heat radiating off the engine 214 00:10:22.600 --> 00:10:24.879 blocks and the friction burning on the tires. 215 00:10:25.039 --> 00:10:27.720 It's the exact same event, but a totally different set 216 00:10:27.759 --> 00:10:29.279 of physical data exactly. 217 00:10:30.279 --> 00:10:32.679 So what about the extremes? What do X rays and 218 00:10:32.799 --> 00:10:33.799 radio waves tell us? 219 00:10:34.440 --> 00:10:37.240 If we push that analogy further into the extreme ends 220 00:10:37.240 --> 00:10:40.480 of the spectrum, the X rays would represent the actual 221 00:10:40.519 --> 00:10:43.039 acoustic shock wave of the collision. 222 00:10:42.679 --> 00:10:43.559 Like the loud crunch. 223 00:10:43.720 --> 00:10:47.320 Yes, the violent immediate sound of metal crushing. X rays 224 00:10:47.360 --> 00:10:50.919 represent the highest energy, the most violent immediate consequence of 225 00:10:50.960 --> 00:10:53.840 the event. They tell us about materials being superheated to 226 00:10:53.960 --> 00:10:56.879 millions of degrees and the immediate vicinity of a massive 227 00:10:56.919 --> 00:10:58.159 gravitational engine. 228 00:10:58.279 --> 00:11:03.759 So X rays equal idiot extreme violence the sound of 229 00:11:03.799 --> 00:11:06.399 the crash. So what do radio waves tell us? Because 230 00:11:06.440 --> 00:11:08.759 we always hear about radio telescopes. 231 00:11:08.679 --> 00:11:11.120 Radio waves sit at the complete opposite end of the 232 00:11:11.159 --> 00:11:14.799 spectrum from X rays. They are low energy with very 233 00:11:14.879 --> 00:11:18.480 long wavelengths. In your car crash analogy, the radio waves 234 00:11:18.480 --> 00:11:21.360 would be the long black skid marks left on the asphalt. 235 00:11:21.519 --> 00:11:23.600 I like that, or maybe the sound of the police 236 00:11:23.600 --> 00:11:26.879 sirens echoing through the neighborhood hours later. They are the 237 00:11:26.919 --> 00:11:28.240 long term aftermath. 238 00:11:28.320 --> 00:11:31.919 But how does an explosion in a vacuum produce radio waves? 239 00:11:32.039 --> 00:11:33.639 There's no air for sound or anything. 240 00:11:33.799 --> 00:11:36.519 It happens through a process called synchrotron. 241 00:11:36.080 --> 00:11:37.639 Radiation sychotron radiation. 242 00:11:37.879 --> 00:11:40.840 Right when a massive explosion happens, it rarely just puffs 243 00:11:40.840 --> 00:11:44.039 out in a perfect sphere. Often it blasts highly concentrated 244 00:11:44.039 --> 00:11:47.639 plumes of material relativistic jets out into space at nearly 245 00:11:47.720 --> 00:11:48.559 the speed of light. 246 00:11:48.519 --> 00:11:49.720 That could cosmic fire hose. 247 00:11:49.840 --> 00:11:53.519 Exactly, As those jets slam into the interstellar gas and 248 00:11:53.600 --> 00:11:56.879 dust that was quietly floating around the star's neighborhood, it 249 00:11:56.960 --> 00:12:01.519 creates a massive shockwave. That shockwave operates like a cosmic 250 00:12:01.559 --> 00:12:02.919 particle accelerator, so. 251 00:12:02.840 --> 00:12:04.559 It's riving up whatever's already out there. 252 00:12:04.720 --> 00:12:08.679 It catches electrons, traps them in magnetic fields, and whips 253 00:12:08.679 --> 00:12:12.679 them around at tremendous speeds. As those electrons spiral around 254 00:12:12.679 --> 00:12:15.720 the magnetic field lines, they bleed off energy in the 255 00:12:15.720 --> 00:12:18.519 form of a steady, glowing hum of radio emission. 256 00:12:18.639 --> 00:12:18.960 Wow. 257 00:12:19.279 --> 00:12:22.039 And because that shockwave takes a long time to plow 258 00:12:22.080 --> 00:12:26.759 through the surrounding gas, that radio hum can last for weeks, months, 259 00:12:26.879 --> 00:12:29.759 or even years after the initial X ray flash has 260 00:12:29.840 --> 00:12:30.279 died out. 261 00:12:30.440 --> 00:12:33.519 Okay, So, armed with that understanding of the spectrum, let's 262 00:12:33.559 --> 00:12:36.039 look at the actual clues the astronomers gathered in the 263 00:12:36.080 --> 00:12:39.399 days following the double flash of our mystery event, because 264 00:12:39.440 --> 00:12:43.240 the timeline of how these different wavelengths faded is bizarre. 265 00:12:42.960 --> 00:12:43.840 Truly bizarre. 266 00:12:43.919 --> 00:12:47.360 First, the X rays, the data shows they vanished rapidly 267 00:12:47.399 --> 00:12:50.720 over a matter of days. That tracks with our engine analogy, right. 268 00:12:50.919 --> 00:12:53.639 The engine turned on, burned its fuel, and shut down. 269 00:12:53.480 --> 00:12:56.720 Permanently, exactly a rapid X ray DEK points strongly to 270 00:12:56.759 --> 00:13:00.240 a highly energetic but very short lived initial burst. The 271 00:13:00.279 --> 00:13:01.360 immediate violence was. 272 00:13:01.480 --> 00:13:04.600 Fast, but then they looked at the radio emissions and 273 00:13:04.639 --> 00:13:08.600 those lingered. They faded much much more slowly, dragging on 274 00:13:08.679 --> 00:13:09.480 over several. 275 00:13:09.240 --> 00:13:13.240 Weeks, which is the definitive smoking gun for an evolving jet. 276 00:13:13.879 --> 00:13:17.120 That tells us that whatever exploded didn't just flash. It 277 00:13:17.159 --> 00:13:20.480 fired a concentrated beam of matter out into space, and 278 00:13:20.519 --> 00:13:23.679 we were watching the slow motion aftermath of that beam 279 00:13:23.840 --> 00:13:25.840 plowing through the cosmic neighborhood. 280 00:13:25.919 --> 00:13:29.120 The skid mark the skid marks exactly Here is where. 281 00:13:28.960 --> 00:13:33.200 It gets really interesting, though. The telescopes also spotted a faint, 282 00:13:33.480 --> 00:13:37.559 fading near infrared source at the exact same location, so 283 00:13:37.600 --> 00:13:41.399 there's some heat, some glowing embers left behind. But incredibly, 284 00:13:41.440 --> 00:13:43.600 and this is the part that makes this specific event 285 00:13:43.679 --> 00:13:48.799 so notorious, there was zero detection at optical wavelengths, nothing. 286 00:13:48.720 --> 00:13:50.559 No visible light whatsoever. 287 00:13:50.120 --> 00:13:52.639 Which is astonishing. Usually when you have an event powerful 288 00:13:52.759 --> 00:13:55.200 enough to blast out high energy X rays and carve 289 00:13:55.240 --> 00:13:59.200 a massive radio emitting jet through interstellar space. You expect 290 00:13:59.240 --> 00:14:01.159 a brilliant flash of visible light. 291 00:14:01.279 --> 00:14:04.039 Oh, without a doubt. A standard supernova, for example, can 292 00:14:04.080 --> 00:14:07.240 outshine its entire host galaxy, and optical light to have 293 00:14:07.279 --> 00:14:10.519 an event this violently energetic be completely optically dark adds 294 00:14:10.559 --> 00:14:12.759 a profound layer of stealth to the phenomenon. 295 00:14:13.000 --> 00:14:15.279 But how do you hide an explosion that big from 296 00:14:15.320 --> 00:14:19.600 regular telescopes? I imagine space is empty, but clearly something 297 00:14:19.720 --> 00:14:20.639 was blocking the view. 298 00:14:20.840 --> 00:14:24.240 It forces us to analyze the environment where this explosion 299 00:14:24.279 --> 00:14:27.679 took place. Optical light is actually quite fragile compared to 300 00:14:27.879 --> 00:14:31.759 X rays or radio waves. Fragile, yeah, it gets easily blocked, scattered, 301 00:14:31.799 --> 00:14:36.039 and absorbed by cosmic dust. We call this process dust extinction. O. 302 00:14:36.960 --> 00:14:39.519 Think of trying to shine a standard flashlight through an 303 00:14:39.559 --> 00:14:44.120 incredibly thick, dense fog. The visible light just diffuses, scatters 304 00:14:44.120 --> 00:14:47.039 off the water droplets, and vanishes after a few feet. 305 00:14:47.399 --> 00:14:49.600 But X rays in radio waves don't care about the. 306 00:14:49.519 --> 00:14:52.279 Fog exactly, and X ray can punch right through that 307 00:14:52.360 --> 00:14:55.679 fog as if it isn't there, and radio waves, being 308 00:14:55.720 --> 00:14:58.440 so long, just roll right over the far particles. 309 00:14:58.600 --> 00:15:02.200 So the complete lack of optical light strongly suggests that 310 00:15:02.279 --> 00:15:06.279 this explosion happened in an incredibly dirty, dusty, chaotic region 311 00:15:06.320 --> 00:15:09.360 of space. The visible light was simply swallowed by the 312 00:15:09.360 --> 00:15:11.960 soot of its own environment before it ever reached Earth. 313 00:15:12.080 --> 00:15:15.320 That's the only logical explanation for the missing optical data. 314 00:15:15.399 --> 00:15:18.200 So to summarize the crime scene for you listening, we 315 00:15:18.279 --> 00:15:21.120 have a physical engine that filed, stalled for three minutes, 316 00:15:21.159 --> 00:15:24.720 and fired again. It generated intense X rays that died 317 00:15:24.759 --> 00:15:27.080 in a matter of days. It fired a jet that 318 00:15:27.159 --> 00:15:31.000 produced synchrotron radio waves for weeks. It left a tiny 319 00:15:31.039 --> 00:15:34.200 thermal signature of heat, and it was completely cloaked in dust, 320 00:15:34.480 --> 00:15:37.559 making it invisible to the naked eye. That is our 321 00:15:37.639 --> 00:15:39.279 exact set of physical clues. 322 00:15:39.360 --> 00:15:42.120 That is the complete profile of our culprit. 323 00:15:41.759 --> 00:15:44.480 Which means we are now ready for the ultimate game 324 00:15:44.559 --> 00:15:48.000 of cosmic elimination. To figure out what this new thing 325 00:15:48.080 --> 00:15:51.679 actually is, scientists couldn't just invent a new theory. They 326 00:15:51.720 --> 00:15:53.759 first had to meticulously prove what it. 327 00:15:53.720 --> 00:15:57.360 Isn't, and astrophysics has a massive lineup of usual suspects 328 00:15:57.360 --> 00:15:57.840 to go through. 329 00:15:57.960 --> 00:16:00.679 Let's walk through that exhausting list, because is watching this 330 00:16:00.720 --> 00:16:04.559 single event systematically dismantle every single existing theory of stellar 331 00:16:04.639 --> 00:16:07.440 death is kind of thrilling. Let's bring in suspects number 332 00:16:07.440 --> 00:16:10.679 one in two title disruption events and X ray binaries. 333 00:16:10.799 --> 00:16:13.000 All right, let's define the physics of those, because they're 334 00:16:13.519 --> 00:16:16.320 some of the most violent events in the universe. A 335 00:16:16.440 --> 00:16:20.679 tidal disruption event, or TDE happens when a star wanders 336 00:16:20.879 --> 00:16:23.960 just a little too close to a supermassive. 337 00:16:23.279 --> 00:16:25.480 Black hole, which is a bad day for the star. 338 00:16:25.440 --> 00:16:28.320 A very bad day. Every black hole has something called 339 00:16:28.320 --> 00:16:31.759 a roche limit. When a star crosses that invisible boundary, 340 00:16:31.960 --> 00:16:34.080 the gravity of the black hole becomes so intense that 341 00:16:34.120 --> 00:16:36.519 it pulls exponentially harder on the nearer side of the 342 00:16:36.559 --> 00:16:37.519 star than the far side. 343 00:16:37.559 --> 00:16:40.240 Oh, I've heard this. The title forces just rip the 344 00:16:40.279 --> 00:16:43.200 structural integrity the start to pieces violently. 345 00:16:43.240 --> 00:16:45.879 It stretches the star out, shredding it into a long 346 00:16:45.960 --> 00:16:50.360 stream of superheated gas, a process cheerfully known by astrophysicists 347 00:16:50.480 --> 00:16:51.840 as spagetification. 348 00:16:52.120 --> 00:16:55.360 Spaghetification. It sounds fun until you realize it's a star 349 00:16:55.440 --> 00:16:56.679 being ripped into a noodle. 350 00:16:56.799 --> 00:16:59.639 Right, And as that shredded star material wraps around the 351 00:16:59.639 --> 00:17:03.159 black hole and collides with itself, it circularizes into an 352 00:17:03.159 --> 00:17:07.319 accretion disc. It heats up immensely through viscous friction and 353 00:17:07.400 --> 00:17:10.839 releases massive amounts of X rays, and it often launches 354 00:17:10.839 --> 00:17:12.000 a jet from its poles. 355 00:17:12.200 --> 00:17:15.319 Okay, so a TDE fits the description perfectly. It's an 356 00:17:15.440 --> 00:17:17.720 X ray transiit with a jet. What about an X 357 00:17:17.799 --> 00:17:18.519 ray binary? 358 00:17:18.680 --> 00:17:22.319 And X ray binary is essentially a localized stellar relationship 359 00:17:22.400 --> 00:17:23.640 gone very wrong. 360 00:17:23.640 --> 00:17:24.799 A toxic relationship. 361 00:17:24.839 --> 00:17:27.920 Oh, incredibly toxic. You have a compact object like a 362 00:17:27.960 --> 00:17:31.119 stellar mass black hole or a highly dense neutron star, 363 00:17:31.559 --> 00:17:35.680 orbiting very closely with the normal living star. The gravity 364 00:17:35.680 --> 00:17:39.200 of the compact object slowly siphons gas off its companion star. 365 00:17:39.319 --> 00:17:40.880 It's just stealing its material, yep. 366 00:17:40.920 --> 00:17:43.319 It pulls the outer layers of the living star across 367 00:17:43.359 --> 00:17:47.039 the gravitational equilibrium point between them, building up that swirling 368 00:17:47.039 --> 00:17:51.200 accretion disc. Periodically, that disc reaches a thermal tipping point, 369 00:17:51.599 --> 00:17:54.599 becomes suddenly unstable, and dumps a massive amount of matter 370 00:17:54.640 --> 00:17:56.039 onto the compact object. 371 00:17:55.759 --> 00:17:57.480 All at once, resulting in a flash, a. 372 00:17:57.440 --> 00:17:59.880 Brilliant, violent outburst of X rays. 373 00:18:00.079 --> 00:18:03.039 So both of those suspects sound incredibly violent. Both produce 374 00:18:03.240 --> 00:18:05.880 X rays, Both involve things being torn apart and eaten 375 00:18:05.920 --> 00:18:09.200 by black holes or neutron stars, which completely fits our 376 00:18:09.240 --> 00:18:11.799 engine theory. So why did the astronomers look at the 377 00:18:11.880 --> 00:18:14.240 data for EP two forty three H five A and 378 00:18:14.279 --> 00:18:15.480 completely throw them out. 379 00:18:15.680 --> 00:18:18.920 It comes entirely down to the mechanical clock. The timescale 380 00:18:18.920 --> 00:18:20.400 of a physics is completely wrong. 381 00:18:20.519 --> 00:18:21.759 Too slow, way too slow. 382 00:18:22.440 --> 00:18:25.279 When a supermassive black hole shreds a star in a 383 00:18:25.319 --> 00:18:30.279 tidal disruption event, it's a messy, prolonged process. The viscous 384 00:18:30.319 --> 00:18:33.880 timescale basically the time it takes for that glowing, superheated 385 00:18:33.920 --> 00:18:37.240 disc of stellar spaghetti to actually drain into the black 386 00:18:37.279 --> 00:18:41.480 hole and cool down takes months, sometimes even years. The 387 00:18:41.640 --> 00:18:44.359 X ray emission drags on and on. 388 00:18:44.279 --> 00:18:46.519 And our events X rays faded completely in a few 389 00:18:46.599 --> 00:18:47.519 days exactly. 390 00:18:47.920 --> 00:18:50.359 The physics of a TDE do not allow an accretion 391 00:18:50.440 --> 00:18:52.400 disc of that size to drain and go dark in 392 00:18:52.440 --> 00:18:55.119 a matter of days. It was way too fast, and 393 00:18:55.160 --> 00:18:59.279 the exact same thermodynamic problem applies to standard X ray binaries. 394 00:18:59.839 --> 00:19:03.079 Accretion disc outbursts typically lasts for several months as the 395 00:19:03.119 --> 00:19:04.920 instability works its way through the disc. 396 00:19:05.039 --> 00:19:06.519 Well, wait, I was reading about this, and there is 397 00:19:06.559 --> 00:19:10.079 a loophole right. The astronomers did consider a very rare, 398 00:19:10.200 --> 00:19:13.960 short lived subclass called fast X ray transience. There are 399 00:19:14.000 --> 00:19:16.200 some X ray binaries out there that can flare up 400 00:19:16.200 --> 00:19:18.480 and fade within a few weeks. Could this just be 401 00:19:18.519 --> 00:19:20.480