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 00:00:27.000 --> 00:00:29.960 Imagine looking up at the night sky. You're just staring 8 00:00:30.000 --> 00:00:31.920 out into deep space, right. 9 00:00:31.879 --> 00:00:33.759 Just a completely clear, dark night. 10 00:00:33.799 --> 00:00:39.520 Exactly, and suddenly you witness an explosion so unfathomably powerful, 11 00:00:39.880 --> 00:00:43.560 so overwhelmingly intense, that it shines ten or maybe even 12 00:00:43.600 --> 00:00:46.600 one hundred times brighter than a standard supernova. 13 00:00:46.759 --> 00:00:49.359 It's a scale of energy that's almost hard to wrap 14 00:00:49.399 --> 00:00:49.920 your head around. 15 00:00:50.200 --> 00:00:52.240 It really is. I mean, we are talking about events 16 00:00:52.240 --> 00:00:55.359 that outshine their entire host galaxies, and not just for 17 00:00:55.399 --> 00:00:57.759 a day or two, but for months at a time. 18 00:00:57.600 --> 00:01:01.000 Which completely breaks the standard models we have for stellar death. 19 00:01:01.159 --> 00:01:04.239 Yes, you are looking at one of the universe's ultimate 20 00:01:04.280 --> 00:01:08.959 thermodynamic mysteries. And today we are stepping into a monumental 21 00:01:09.000 --> 00:01:13.359 breakthrough in astrophysics. We are exploring the very first confirmed 22 00:01:13.400 --> 00:01:15.840 observation of the birth of a magnetar. 23 00:01:16.040 --> 00:01:18.159 It's an incredible milestone. 24 00:01:17.560 --> 00:01:20.159 It really is. It's a discovery that finally solves a 25 00:01:20.200 --> 00:01:23.599 sixteen year old cosmic cold case, and in the process 26 00:01:23.599 --> 00:01:27.920 it proves that Einstein's general relativity isn't just some elegant 27 00:01:27.959 --> 00:01:30.120 mathematical framework for describing gravity. 28 00:01:30.239 --> 00:01:33.840 No, it is actively physically shaping the light curves of 29 00:01:33.920 --> 00:01:35.879 exploding stars exactly. 30 00:01:36.200 --> 00:01:39.480 So our mission today is to unpack exactly what these 31 00:01:39.480 --> 00:01:43.120 bizarre cosmic engines are. We're going to analyze how a 32 00:01:43.159 --> 00:01:46.400 mathematically precise sort of chirp in the light of a 33 00:01:46.439 --> 00:01:49.959 galaxy a billion light years away cracked the case. 34 00:01:49.799 --> 00:01:53.920 And examine why this fundamentally shifts our entire paradigm regarding 35 00:01:54.000 --> 00:01:56.200 the universe's most extreme fireworks. 36 00:01:56.359 --> 00:01:59.920 Because the implications of this observation really just they can 37 00:02:00.159 --> 00:02:00.799 be overstated. 38 00:02:00.840 --> 00:02:04.560 They cannot. We are witnessing this incredibly rare moment where 39 00:02:04.959 --> 00:02:10.520 highly complex, predictive theoretical physics seamlessly aligns with observational. 40 00:02:09.919 --> 00:02:11.759 Reality, which doesn't happen every day. 41 00:02:11.960 --> 00:02:15.719 No it doesn't. For years, astrophysicists have possessed the mathematical 42 00:02:15.719 --> 00:02:19.199 models detailing the energy budgets required to power these events, 43 00:02:19.360 --> 00:02:21.919 we understood the theoretical limits of stellar collapse. 44 00:02:22.080 --> 00:02:24.560 The math was there on the whiteboard exactly. 45 00:02:24.520 --> 00:02:27.439 But possessing a theoretical model of a central engine is 46 00:02:27.479 --> 00:02:30.599 a far cry from empirically capturing that engine in the 47 00:02:30.639 --> 00:02:32.479 act of altering its surrounding environment. 48 00:02:32.599 --> 00:02:34.319 Right, actually seeing it happen. 49 00:02:34.360 --> 00:02:40.479 To finally isolate the specific relativistic mechanics powering these blinding explosions. 50 00:02:41.000 --> 00:02:44.479 It not only validates decades of rigorous computational work, but 51 00:02:44.560 --> 00:02:48.719 it forces us to reevaluate the dynamical evolution of stellar death. 52 00:02:48.960 --> 00:02:51.560 It takes it from theory to reality. 53 00:02:51.840 --> 00:02:55.439 It transitions the magnetar from a mathematical necessity to an 54 00:02:55.479 --> 00:02:57.199 observable mechanical reality. 55 00:02:57.240 --> 00:03:00.319 Okay, so to truly appreciate the magnitude of the sopsation, 56 00:03:00.759 --> 00:03:03.960 you really have to understand the specific thermodynamic puzzle that 57 00:03:04.039 --> 00:03:06.560 emerged back in the early two thousands. 58 00:03:06.159 --> 00:03:08.360 Right with the discovery of superluminous supernova. 59 00:03:08.479 --> 00:03:12.479 Exactly because anyone familiar with stellar evolution knows the standard 60 00:03:12.520 --> 00:03:13.560 core collapse model. 61 00:03:13.719 --> 00:03:15.199 The textbook definition. 62 00:03:14.919 --> 00:03:17.919 Right, a massive star says something twenty five times our 63 00:03:17.960 --> 00:03:22.039 Sun exhausts its nuclear fuel, the iron core collapses under 64 00:03:22.080 --> 00:03:25.759 its own gravity. And the resulting rebound drives a shockwave 65 00:03:25.840 --> 00:03:27.439 through the outer envelope. 66 00:03:27.039 --> 00:03:30.439 Creating a spectacular explosion boom supernova. 67 00:03:30.520 --> 00:03:33.240 Now, the energy budget for that standard event is relatively 68 00:03:33.319 --> 00:03:36.680 well understood, right. It relies heavily on the radioactive decay 69 00:03:36.719 --> 00:03:38.479 of elements like nickel fifty six. 70 00:03:38.319 --> 00:03:39.680 Since the size in the blast itself. 71 00:03:39.759 --> 00:03:43.080 Yes, and that decay powers the late stage light curve. 72 00:03:43.080 --> 00:03:47.240 It's what keeps it glowing. But these superluminous events, they 73 00:03:47.360 --> 00:03:49.479 fundamentally broke that energy budget. 74 00:03:49.520 --> 00:03:50.840 They absolutely shattered it. 75 00:03:50.719 --> 00:03:54.159 Because they were outputting these sustained luminosities that simply could 76 00:03:54.240 --> 00:03:57.520 not be explained by the standard mass limits of radioactive decay. 77 00:03:58.240 --> 00:04:00.520 Let's unpack that a bit. Why could to just be 78 00:04:00.639 --> 00:04:02.840 a really big normal supernova. 79 00:04:02.960 --> 00:04:05.639 Well, the nickel fifty six decay model works perfectly for 80 00:04:05.680 --> 00:04:09.439 a standard core collapse supernova because the diffusion of photons 81 00:04:09.479 --> 00:04:12.960 through the expanding ejecta matches the decay rate of those 82 00:04:13.039 --> 00:04:18.079 radioactive isotopes. Okay, But with superluminous supernova, the sheer volume 83 00:04:18.079 --> 00:04:21.680 of photons being emitted and over such an extended timescale 84 00:04:21.720 --> 00:04:23.519 it created this glaring discrepancy. 85 00:04:23.680 --> 00:04:25.720 Like the math just stopped working completely. 86 00:04:25.759 --> 00:04:27.839 If you attempt to model the light curve of a 87 00:04:27.879 --> 00:04:31.800 superluminous event using only nickel fifty six, the required mass 88 00:04:31.800 --> 00:04:34.600 of the nickel alone often exceeds the total mass of 89 00:04:34.639 --> 00:04:35.959 the entire progenitor star. 90 00:04:36.240 --> 00:04:38.800 Wow, so you'd need more nickel than the star even 91 00:04:38.800 --> 00:04:39.839 had stuff to begin with. 92 00:04:40.160 --> 00:04:43.160 Exactly, it is a physical impossibility. This meant that the 93 00:04:43.240 --> 00:04:46.160 kinetic energy of the initial shock wave and the subsequent 94 00:04:46.240 --> 00:04:50.199 radioactive decay were utterly insufficient to explain what we were seeing. 95 00:04:50.360 --> 00:04:52.120 So something else had to be powering it. 96 00:04:52.480 --> 00:04:56.480 Right, The expanding shell of stellar debris required a continuous, 97 00:04:56.839 --> 00:05:01.000 immense injection of fresh thermal energy a central engine, yes, 98 00:05:01.040 --> 00:05:04.279 an engine operating long after the initial collapse, just pumping 99 00:05:04.439 --> 00:05:07.879 energy in to maintain that extraordinary luminosity. 100 00:05:07.519 --> 00:05:10.639 Which brings us to the theoretical framework proposed back in 101 00:05:10.680 --> 00:05:14.720 twenty ten. We had theorists Dan Kaysen at UC Berkeley, 102 00:05:15.199 --> 00:05:19.360 Lars Buildston and Stan Woosley at UC Santa Cruz, brilliant minds, 103 00:05:19.519 --> 00:05:24.560 and they independently converged on this genuinely radical mechanism. They 104 00:05:24.600 --> 00:05:28.839 proposed that the necessary energy injection wasn't coming from radioactive. 105 00:05:28.199 --> 00:05:29.759 Decay at all, not even a little bit. 106 00:05:30.120 --> 00:05:32.519 It was coming from the rotational kinetic energy of a 107 00:05:32.560 --> 00:05:36.879 newly formed magnetar. Now, okay, let's unpack this To understand 108 00:05:36.920 --> 00:05:39.639 why this hypothesis was so compelling. We really need to 109 00:05:39.639 --> 00:05:42.480 look at the extreme parameters of what a magnetar. 110 00:05:42.040 --> 00:05:45.360 Actually is, especially in the immediate aftermath of a core collapse. 111 00:05:45.759 --> 00:05:49.040 Right, because we aren't just talking about a highly magnetized 112 00:05:49.079 --> 00:05:52.480 neutron star here. We are talking about an object operating 113 00:05:52.480 --> 00:05:55.120 at the absolute extremes of physics. 114 00:05:55.199 --> 00:05:59.000 That's right, When the iron core of a sufficiently massive 115 00:05:59.040 --> 00:06:03.199 star collapses into a neutron star, it conserves the angular 116 00:06:03.199 --> 00:06:05.839 momentum of the original stellar core. 117 00:06:05.879 --> 00:06:07.879 Like an ice skater pulling their arms in. 118 00:06:07.959 --> 00:06:11.600 A perfect analogy. Because the radius shrinks from thousands of 119 00:06:11.639 --> 00:06:16.160 kilometers down to roughly ten kilometers, the rotation rate just skyrockets. 120 00:06:16.279 --> 00:06:18.199 It spins up insanely fast. 121 00:06:18.319 --> 00:06:22.600 And if the progenitor star possessed a strong initial magnetic field, 122 00:06:23.319 --> 00:06:26.839 or if convective dynamos during the collapse amplify that field, 123 00:06:27.120 --> 00:06:28.319 you generate a magnetar. 124 00:06:28.439 --> 00:06:30.040 And the numbers here are just wild. 125 00:06:30.160 --> 00:06:32.399 We are looking at surface magnetic fields on the order 126 00:06:32.399 --> 00:06:34.160 of ten to the fourteenth or even ten to the 127 00:06:34.199 --> 00:06:35.519 fifteenth gaals. 128 00:06:35.319 --> 00:06:37.399 Which, to put that in perspective for you listening, that 129 00:06:37.480 --> 00:06:40.360 is roughly a quadrillion times stronger than Earth's magnetic field. 130 00:06:40.439 --> 00:06:44.639 It's almost unimaginable, and in its infancy right after the collapse, 131 00:06:44.920 --> 00:06:48.560 this ten kilometer wide sphere can rotate with a spin 132 00:06:48.639 --> 00:06:50.600 period of just one or two milliseconds. 133 00:06:50.800 --> 00:06:52.360 So wait, let me just make sure we're painting the 134 00:06:52.439 --> 00:06:55.240 right picture here. You have a mass greater than our 135 00:06:55.360 --> 00:06:59.000 sun correct compressed into the size of a small city. Yes, 136 00:06:59.199 --> 00:07:00.759 spinning a th tho times a. 137 00:07:00.759 --> 00:07:02.920 Second, more than a thousand sometimes. 138 00:07:02.519 --> 00:07:06.319 In generating a magnetic field so intense it literally distorts 139 00:07:06.319 --> 00:07:08.160 the electron clouds of atoms. 140 00:07:08.199 --> 00:07:10.399 It bends the very fabric of atomic structure. 141 00:07:10.480 --> 00:07:14.600 Yes, that is terrifying and amazing. So the ksin Buildston 142 00:07:14.680 --> 00:07:20.000 and Woosley model hypothesize that this extreme object basically acts 143 00:07:20.040 --> 00:07:23.560 as a macroscopic particle accelerator exactly. 144 00:07:23.759 --> 00:07:28.120 The rapidly spinning, hyperstrong magnetic field generates an immense electric field, 145 00:07:28.600 --> 00:07:33.600 and that accelerates charged particles to relativistic speeds, driving this continuous, 146 00:07:33.639 --> 00:07:38.279 incredibly powerful wind of high energy radiation in electron positron. 147 00:07:37.800 --> 00:07:41.319 Pairs and this is the mechanism known as spin down luminosity. 148 00:07:41.519 --> 00:07:45.519 That's the term. Yes, the magnetar is essentially breaking. As 149 00:07:45.560 --> 00:07:50.000 it spins, it's transferring its massive rotational kinetic energy into 150 00:07:50.000 --> 00:07:52.839 the surrounding environment via magnetic dipole radiation. 151 00:07:53.279 --> 00:07:55.959 So it's slowing down but dumping all that energy into 152 00:07:56.000 --> 00:07:56.959 the debris around it. 153 00:07:57.360 --> 00:08:01.959 Exactly, this relativistic winds slams into the inner boundary of 154 00:08:02.000 --> 00:08:06.480 the expanding supernova ejecta, and that generates a highly pressurized, 155 00:08:06.560 --> 00:08:07.560 superheated bubble. 156 00:08:07.680 --> 00:08:09.639 Okay, I can visualize that as. 157 00:08:09.439 --> 00:08:13.120 The magnetar spins down over days and weeks, it continuously 158 00:08:13.160 --> 00:08:16.519 pumps thermal energy into the expanding debris. Now, because the 159 00:08:16.560 --> 00:08:19.839 ejecta is highly opaque as a very high optical depth, 160 00:08:20.279 --> 00:08:23.040 this injected energy cannot escape immediately. 161 00:08:23.079 --> 00:08:24.120 It's trapped, right. 162 00:08:24.279 --> 00:08:27.759 It diffuses slowly heating the outer layers and powering the 163 00:08:27.839 --> 00:08:32.080 brilliant sustained light curve that defines a superluminous supernova. 164 00:08:32.480 --> 00:08:35.720 And Dan Kasen elegantly referred to this entire mechanism as 165 00:08:35.759 --> 00:08:37.279 a theorist's magic. 166 00:08:37.120 --> 00:08:38.919 Trick, which is such an apt description. 167 00:08:39.080 --> 00:08:42.840 It really is that phrasing perfectly captures the frustration and 168 00:08:42.840 --> 00:08:45.879 the brilliance of the model because the math checked out flawlessly. 169 00:08:45.960 --> 00:08:48.440 It did. If you put a one millisecond spin period 170 00:08:48.559 --> 00:08:51.600 and attend to the fourteenth goss magnetic field into the equations, 171 00:08:51.879 --> 00:08:55.799 the resulting spin down luminosity perfectly matches the light curves 172 00:08:55.919 --> 00:08:57.200 of Superluminus supernova. 173 00:08:57.360 --> 00:08:59.200 It's a perfect fit. But the trick is that the 174 00:08:59.200 --> 00:08:59.919 central engine is. 175 00:09:00.159 --> 00:09:02.320 Entirely obscured, hidden behind the cretain. 176 00:09:02.679 --> 00:09:07.240 Exactly, the magnetar is buried deep beneath light years of dense, 177 00:09:07.519 --> 00:09:12.360 optically thick stellar debris. You cannot observe the magnetar directly 178 00:09:12.399 --> 00:09:16.320 in the optical X ray or gamma ray spectrums because 179 00:09:16.360 --> 00:09:18.279 the ejecta just blocks everything. 180 00:09:18.399 --> 00:09:20.600 It acts as an impenetrable wall, right. 181 00:09:20.519 --> 00:09:23.399 So you are only seeing the glowing exhaust. You are 182 00:09:23.480 --> 00:09:24.960 never seeing the engine itself. 183 00:09:25.039 --> 00:09:28.279 And that's a huge problem for astronomy. The scientific method 184 00:09:28.360 --> 00:09:32.279 demands empirical verification. For over a decade, this was the 185 00:09:32.320 --> 00:09:35.799 central observational challenge in the field. How do you confirm 186 00:09:35.840 --> 00:09:38.240 the existence of an engine you fundamentally cannot see. 187 00:09:38.320 --> 00:09:40.080 You can't just say, well, the math works, so let's 188 00:09:40.080 --> 00:09:40.679 call it a day. 189 00:09:40.879 --> 00:09:44.440 No, you absolutely cannot. The theoretical community knew that if 190 00:09:44.440 --> 00:09:48.200 a magnetar was responsible, its energy deposition was making the 191 00:09:48.200 --> 00:09:51.519 debris superluminous, but there was no secondary signature. 192 00:09:51.679 --> 00:09:53.320 No smoking gun, right, There's. 193 00:09:53.159 --> 00:09:56.639 No independent variable that could do definitively rule out other potential, 194 00:09:56.679 --> 00:10:00.960 albeit less likely, power sources. To confirm the magnet our hypothesis, 195 00:10:01.159 --> 00:10:05.320 astronomers needed a highly specific dynamic signature in the light curve. 196 00:10:05.399 --> 00:10:07.759 Something that could only be produced by the geometry and 197 00:10:07.840 --> 00:10:12.360 mechanics of a spinning, highly magnetized neutron star precisely, and 198 00:10:12.399 --> 00:10:17.320 that specific signature finally materialized. We fast forward to December 199 00:10:17.320 --> 00:10:20.879 twenty twenty four, shifting this from a theoretical exercise into 200 00:10:20.919 --> 00:10:23.639 an unprecedented global observation. 201 00:10:23.480 --> 00:10:26.080 The discovery of SN twenty twenty four or five. 202 00:10:26.320 --> 00:10:30.440 Yes, a supernova situated at a red shift that places 203 00:10:30.480 --> 00:10:34.480 it roughly one billion light years from Earth, a staggering distance, 204 00:10:34.639 --> 00:10:38.240 and at that distance capturing the high resolution, high cadence 205 00:10:38.320 --> 00:10:41.559 data required to analyze the subtle dynamics of a light curve. 206 00:10:42.240 --> 00:10:44.679 I mean that that is an engineering marvel in itself. 207 00:10:44.919 --> 00:10:45.600 It truly is. 208 00:10:45.799 --> 00:10:50.240 This observation relied heavily on the less cumbers Observatory or LCO, 209 00:10:50.720 --> 00:10:54.399 which is this globally distributed network of twenty seven robotic. 210 00:10:54.039 --> 00:10:57.080 Telescopes, and the architecture of the LCO network is absolutely 211 00:10:57.120 --> 00:11:00.639 critical to this discovery. Tell us why well adding transient 212 00:11:00.679 --> 00:11:03.759 astronomical events. The biggest enemies of data collection are daylight 213 00:11:03.799 --> 00:11:04.240 and weather. 214 00:11:04.399 --> 00:11:06.519 Right the sun comes up and you're done, exactly. 215 00:11:06.799 --> 00:11:09.320 A single observatory can only track an object for a 216 00:11:09.360 --> 00:11:12.200 fraction of a day, leading to significant gaps in the 217 00:11:12.200 --> 00:11:16.399 photometric data. But by utilizing a network of robotic telescopes 218 00:11:16.519 --> 00:11:22.840 distributed across multiple longitudes, the LCO allows for continuous, unbroken observation. 219 00:11:22.720 --> 00:11:23.559 Like a relay race. 220 00:11:23.840 --> 00:11:26.600 Exactly like a relay, As the Earth rotates and the 221 00:11:26.639 --> 00:11:29.399 target dips below the horizon for a telescope in Hawaii, 222 00:11:29.720 --> 00:11:32.320 a telescope in Australia is already picking it up. Wow, 223 00:11:32.399 --> 00:11:35.240 and it's followed by South Africa and so on. This 224 00:11:35.360 --> 00:11:39.679 global relay enables astronomers to generate a pristine high cadence 225 00:11:39.759 --> 00:11:43.440 light curve documenting the exact fluctuations in brightness without the 226 00:11:43.440 --> 00:11:45.039 typical diurnal interruptions. 227 00:11:45.159 --> 00:11:48.840 It's just relentless observation. And this relentless observation capability was 228 00:11:48.879 --> 00:11:51.799 applied to SN twenty twenty four or five for over 229 00:11:51.840 --> 00:11:53.480 two hundred consecutive. 230 00:11:53.039 --> 00:11:54.759 Days, a massive stakeout. 231 00:11:54.879 --> 00:11:58.559 Basically, graduate student Joseph Fara at UC Santa Barbara, working 232 00:11:58.639 --> 00:12:02.960 with LCO astronomer Andy Howe, meticulously analyzed this massive data stream. 233 00:12:03.519 --> 00:12:03.679 Now. 234 00:12:03.720 --> 00:12:06.399 Initially, the light curve behaved exactly as expected for a 235 00:12:06.440 --> 00:12:07.399 super luminous event. 236 00:12:07.480 --> 00:12:10.320 They climbed in brightness, hitting its peak luminosity around fifty 237 00:12:10.360 --> 00:12:11.480 days post explosion. 238 00:12:11.679 --> 00:12:16.039 The energy output was staggering, entirely consistent with the magnetar 239 00:12:16.159 --> 00:12:19.759 spin down model, but the critical anomaly didn't appear during 240 00:12:19.799 --> 00:12:20.200 the peak. 241 00:12:20.360 --> 00:12:23.799 No, it appeared during the fading phase, the decaying tail. 242 00:12:23.679 --> 00:12:26.679 Of the light curve right. Normally, as the central engine 243 00:12:26.720 --> 00:12:30.120 spins down and the expanding edjecta cools what happens. 244 00:12:30.320 --> 00:12:35.159 Typically, the light curve should follow a relatively smooth, predictable 245 00:12:35.600 --> 00:12:38.720 exponential decay. It just slowly fades out. 246 00:12:38.799 --> 00:12:42.200 But the photometry for twenty twenty four A five deviated 247 00:12:42.279 --> 00:12:46.960 violently from a smooth fade. The luminosity began to oscillate. 248 00:12:46.720 --> 00:12:49.279 The brightness dropped, then spiked, then dropped again. 249 00:12:49.399 --> 00:12:52.240 It generated this series of discrete bumps in the light curve. 250 00:12:52.559 --> 00:12:55.440 And this wasn't random noise or chaotic flickering from bad 251 00:12:55.480 --> 00:12:59.480 weather on Earth. The data revealed exactly four distinct high 252 00:12:59.480 --> 00:13:00.559 amplitude bumps. 253 00:13:00.639 --> 00:13:03.720 And what's fascinating here is the structural nature of those forbumps. 254 00:13:04.080 --> 00:13:07.200 That's where the data completely diverges from standard models. 255 00:13:06.879 --> 00:13:08.960 Because they weren't evenly space exactly. 256 00:13:09.200 --> 00:13:11.840 Parah noted that the temporal spacing between these peaks was 257 00:13:11.840 --> 00:13:16.320 not uniform. The period of the oscillations was gradually precisely shortening, so. 258 00:13:16.320 --> 00:13:18.120 They were getting closer together, right. 259 00:13:18.519 --> 00:13:21.039 The time between the first and second bump was longer 260 00:13:21.080 --> 00:13:22.759 than the time between the second and third. 261 00:13:22.639 --> 00:13:24.720 Which was longer than the time between the third and 262 00:13:24.759 --> 00:13:25.879 fourth precisely. 263 00:13:26.360 --> 00:13:30.600 And Pharah used the perfect analogy to visualize this data set. 264 00:13:31.320 --> 00:13:32.919 He compared it to a chirp. 265 00:13:33.759 --> 00:13:37.720 I love that analogy. Let's break that down explicitly for everyone. 266 00:13:37.799 --> 00:13:40.159 If you look at the waveform of a bird's chirp 267 00:13:40.240 --> 00:13:43.279 or even a gravitational wave merger, the frequency of the 268 00:13:43.320 --> 00:13:45.840 oscillation increases as the event progresses. 269 00:13:45.919 --> 00:13:49.840 The sound gets higher pitched because the waves are compressing temporally. 270 00:13:49.559 --> 00:13:52.480 Exactly, and the light curve of the supernova was doing 271 00:13:52.480 --> 00:13:57.360 the exact same thing, accelerating its stroping effect as it faded, and. 272 00:13:57.320 --> 00:14:02.919 The presence of this specific accelerating periodicity immediately invalidated the 273 00:14:03.000 --> 00:14:07.039 leading alternative explanations for fluctuations in supernova light curves. 274 00:14:07.120 --> 00:14:10.279 Because in previous observations, if a light curve exhibited may 275 00:14:10.279 --> 00:14:13.559 be a singular bump or a minor fluctuation, what did 276 00:14:13.600 --> 00:14:15.440 astronomers usually lame it on? 277 00:14:15.639 --> 00:14:19.519 They often attributed it to circumstellar interaction, the idea being 278 00:14:19.519 --> 00:14:22.679 that if the progenitor star underwent heavy mass loss episodes 279 00:14:22.720 --> 00:14:26.080 prior to collapsing, it would be surrounded by dense shells 280 00:14:26.080 --> 00:14:27.000 of gas. 281 00:14:26.720 --> 00:14:28.679 Like blowing smoke rings before it dies. 282 00:14:28.879 --> 00:14:34.240 Essentially yes, and when the highly supersonic supernova shockwave impacts 283 00:14:34.279 --> 00:14:38.039 one of these circumstellar shells, the kinetic energy is converted 284 00:14:38.080 --> 00:14:42.159 into thermal radiation that creates a temporary flare or bump 285 00:14:42.399 --> 00:14:43.559 in the observed light curve. 286 00:14:44.000 --> 00:14:46.840 But the problem with the circumstellar interaction model here is 287 00:14:46.840 --> 00:14:48.399 that it's inherently stochastic. 288 00:14:48.639 --> 00:14:49.879 It's chickotic, right. 289 00:14:50.039 --> 00:14:53.759 The mass loss history of a dying massive star is messy. 290 00:14:54.240 --> 00:14:57.720 The distribution of surrounding gas is highly irregular. You might 291 00:14:57.720 --> 00:15:01.399 get one collision or perhaps a couple based out completely randomly, 292 00:15:01.440 --> 00:15:03.320 depending on where the clumps of gas just happen to 293 00:15:03.320 --> 00:15:04.120 be exactly. 294 00:15:04.399 --> 00:15:08.360 But you absolutely do not get four massive, mathematically organized 295 00:15:08.360 --> 00:15:11.879 collisions that perfectly accelerate in frequency. It's just too clean, 296 00:15:12.120 --> 00:15:16.279 way too clean. The precise periodicity of the chirp fundamentally 297 00:15:16.320 --> 00:15:20.679 requires a rotating dynamic mechanical system operating from the inside out, 298 00:15:21.080 --> 00:15:23.120 not a random series of external collisions. 299 00:15:23.279 --> 00:15:26.679 Okay, So this realization forced Farah and his team to 300 00:15:26.720 --> 00:15:31.679 construct totally novel mechanical model, one capable of producing and 301 00:15:31.799 --> 00:15:35.759 accelerating strobing light effect from deep within the opaque. 302 00:15:35.399 --> 00:15:38.720 Ejecta, and they turn to the dynamics of fallback accretion. 303 00:15:38.960 --> 00:15:42.360 Let's talk about fallback accretion, because when a core collapse 304 00:15:42.440 --> 00:15:48.000 explosion occurs, not all of the stellar material achieves escape velocity, right. 305 00:15:47.960 --> 00:15:51.440 Right, A significant fraction of the inner envelope, lacking the 306 00:15:51.519 --> 00:15:54.360 kinetic energy to overcome the immense gravity of the newly 307 00:15:54.399 --> 00:15:58.480 formed neutron star, just stalls and then it falls back inward. 308 00:15:58.679 --> 00:16:01.360 It rains back down on the cour precisely. 309 00:16:01.240 --> 00:16:03.960 But due to the conservation of angular momentum from the 310 00:16:03.960 --> 00:16:08.440 original stars rotation. This falling material cannot drop straight down 311 00:16:08.480 --> 00:16:10.039 onto the neutron star's surface. 312 00:16:10.120 --> 00:16:11.559 It cat just plunge in No. 313 00:16:11.840 --> 00:16:15.840 Instead, its spirals inward, flattening into a dense, superheated accretion disc. 314 00:16:16.120 --> 00:16:18.799 And this is where the geometric complexities of the explosion 315 00:16:18.879 --> 00:16:22.960 become paramount Because a supernova is not a perfectly spherical, 316 00:16:23.120 --> 00:16:25.799 highly symmetrical event. It's not this neat little drawing in 317 00:16:25.799 --> 00:16:26.960 a textbook. 318 00:16:26.639 --> 00:16:29.600 Not at all. The core collapse and the subsequent neutrino 319 00:16:29.720 --> 00:16:34.399 driven convection are wildly turbulent. Neutron stars often receive massive 320 00:16:34.519 --> 00:16:39.320 kicks during formation picks. Yes, asymmetrical forces during the explosion 321 00:16:39.360 --> 00:16:42.879 can literally kick the neutron star, accelerating it to hundreds 322 00:16:42.879 --> 00:16:45.120 of kilometers per second in a specific direction. 323 00:16:45.360 --> 00:16:45.879 Wow. 324 00:16:46.200 --> 00:16:50.000 And because of this inherent chaos and asymmetry, the angular 325 00:16:50.039 --> 00:16:54.360 momentum vector of the fallback material is almost never perfectly 326 00:16:54.399 --> 00:16:58.559 aligned with the spin axis of the central magnetar. 327 00:16:58.200 --> 00:17:01.919 Which creates a profound misalignment, a huge one. You have 328 00:17:01.960 --> 00:17:05.160 a central magnetar spinning on one axis right, surrounded by 329 00:17:05.160 --> 00:17:09.400 a massive superheated accretion disc rotating on an entirely different 330 00:17:09.440 --> 00:17:10.519 tilted axis as a. 331 00:17:10.440 --> 00:17:13.119 Wildly unstable geometric configuration. 332 00:17:12.640 --> 00:17:16.480 And this configuration, a misaligned disk orbiting a rapidly rotating 333 00:17:16.559 --> 00:17:20.759 ultracompact mass, is the precise environment where things get truly weird. 334 00:17:21.240 --> 00:17:23.960 This is where the most extreme predictions of Albert Einstein's 335 00:17:23.960 --> 00:17:26.319 general relativity step in and become dominant. 336 00:17:26.559 --> 00:17:28.920 Specifically, we have to look at the dynamics governed by 337 00:17:29.000 --> 00:17:32.799 the Kerr metric. The cur metric, yes, which describes the 338 00:17:32.839 --> 00:17:37.200 geometry of empty space time around a rotating, uncharged Axley 339 00:17:37.240 --> 00:17:40.960 symmetric black hole or in this case, a rapidly rotating 340 00:17:40.960 --> 00:17:41.640 neutron star. 341 00:17:41.920 --> 00:17:46.160 Okay, so Einstein's general relativity dictates something called frame dragging 342 00:17:46.680 --> 00:17:48.200 or lens thuring procession. 343 00:17:48.440 --> 00:17:49.279 That's the punchline. 344 00:17:49.359 --> 00:17:53.039 Yes, Let's break this down because in a classical Newtonian framework, 345 00:17:53.559 --> 00:17:57.000 gravity is simply a force acting across a distance, like 346 00:17:57.160 --> 00:17:58.279 an invisible tether. 347 00:17:58.599 --> 00:18:01.559 Right. Newton sees space as a static stage. 348 00:18:01.880 --> 00:18:05.000 But in general relativity, gravity is the curvature of space 349 00:18:05.039 --> 00:18:07.839 time itself. So when you have an object as dense 350 00:18:07.839 --> 00:18:11.640 as a magnetar spinning at incredibly high velocities, it doesn't 351 00:18:11.640 --> 00:18:13.759 just sit in a static depression in space time. 352 00:18:13.960 --> 00:18:17.440 Not at all, the mass and the extreme angular momentum 353 00:18:17.480 --> 00:18:21.200 of the magnetar literally grab the fabric of space time 354 00:18:21.240 --> 00:18:23.279 itself and drag it along in the direction of the. 355 00:18:23.319 --> 00:18:26.240 Rotation, like spinning a bowling ball in a vat of honey. 356 00:18:26.319 --> 00:18:29.119 That's a great visual. Space and time are physically twisted 357 00:18:29.119 --> 00:18:30.119 around the central engine. 358 00:18:30.160 --> 00:18:32.640 And because space time is being dragged, it exerts a 359 00:18:32.680 --> 00:18:35.599 profound mechanical force on anything orbiting within it. 360 00:18:35.720 --> 00:18:38.240 Yes, and remember our misaligned deccretion disc. 361 00:18:38.599 --> 00:18:42.279 It's sitting directly within this heavily twisted region of space time. 362 00:18:42.440 --> 00:18:46.319 Exactly because the disc's orbital plane is tilted relative to 363 00:18:46.319 --> 00:18:50.559 the magnetar's equatorial plane, the frame dragging effect applies a 364 00:18:50.599 --> 00:18:52.519 differential torque across the disc. 365 00:18:52.880 --> 00:18:54.519 It's twisting the disc it is. 366 00:18:55.119 --> 00:18:59.200 This torque forces the entire accretion disk to process so 367 00:18:59.359 --> 00:19:03.240 instead smoothly like a stationary record, the entire plane of 368 00:19:03.279 --> 00:19:06.440 the disc wabbles around the magnetar's spin axis, like a 369 00:19:06.519 --> 00:19:09.839 gyroscope or a spinning top that's starting to lose momentum. 370 00:19:10.160 --> 00:19:13.039 It wobbles, and because the inner regions of the disc 371 00:19:13.079 --> 00:19:16.680 are tightly coupled together magnetically and frictionally, the disc tends 372 00:19:16.720 --> 00:19:20.319 to process as a single rigid solid body. 373 00:19:20.160 --> 00:19:23.240 So you've got this tilted dick wobbling as one solid piece, 374 00:19:23.559 --> 00:19:26.880 and the solid body procession of the missiligned disc provides 375 00:19:26.920 --> 00:19:30.119 the exact mechanism needed to create the anomalous light curve. 376 00:19:30.319 --> 00:19:31.440 It's the lighthouse effect. 377 00:19:31.559 --> 00:19:34.200 Yes, let's visualize the mechanics. Here. We have the central 378 00:19:34.240 --> 00:19:38.039 magnetar pumping out immense spin down luminosity, thermalizing the inner 379 00:19:38.079 --> 00:19:40.240 region of the ejecta. It's brilliantly bright. 380 00:19:40.440 --> 00:19:43.480 But surrounding that central light source is this thick, opaque, 381 00:19:43.480 --> 00:19:44.640 tilted accretion disc. 382 00:19:45.039 --> 00:19:48.680 Right. And as the disc processes, as it wobbles, driven 383 00:19:48.720 --> 00:19:52.119 by the dragging of space time, its orientation relative to 384 00:19:52.160 --> 00:19:54.200 our line of sight constantly changes. 385 00:19:54.359 --> 00:19:58.319 It functions precisely like a cosmic lighthouse, but functioning through 386 00:19:58.359 --> 00:20:00.960 obscuration rather than directed. 387 00:20:00.519 --> 00:20:03.640 Emission, meaning it blocks the light instead of shining a beam. 388 00:20:04.039 --> 00:20:08.599 Exactly when the processing discs raised thicker edge wabbles into 389 00:20:08.640 --> 00:20:11.960 our line of sight, it heavily obscures the brilliant thermal 390 00:20:12.039 --> 00:20:13.880 radiation from the central engine. 391 00:20:13.559 --> 00:20:16.279 Which causes a sharp dip in the observed brightness. 392 00:20:16.599 --> 00:20:20.000 Right and then, as the disc continues its procession, and 393 00:20:20.000 --> 00:20:22.599 that thick edge rotates out of our view. We are 394 00:20:22.599 --> 00:20:25.960 granted a clearer, less obstructive view of the central engines'. 395 00:20:25.680 --> 00:20:29.039 Emission, resulting in a spike or a bump in the 396 00:20:29.119 --> 00:20:29.559 light curve. 397 00:20:29.640 --> 00:20:32.799 The entire inner geometry of the supernova is basically acting 398 00:20:32.839 --> 00:20:34.839 as a massive strobing shutter. 399 00:20:34.799 --> 00:20:38.440 That perfectly explains the periodic bumps. But the real genius 400 00:20:38.440 --> 00:20:41.319 of this model, the AHA moment, lies in how it 401 00:20:41.359 --> 00:20:45.079