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 00:00:27.239 --> 00:00:32.240 Somewhere out there, right like deep in the dustiest, absolutely 8 00:00:32.280 --> 00:00:35.679 most violent center of our galaxy, there is this invisible 9 00:00:35.719 --> 00:00:39.560 cosmic metronome that's just been ticking away for over thirty years. 10 00:00:39.759 --> 00:00:42.320 Yeah, it's pretty wild to think about. 11 00:00:42.159 --> 00:00:45.039 Right, Just imagine the sheer scale of that for a second. 12 00:00:45.159 --> 00:00:48.880 Every twenty minute, just boom, a massive blast of radio 13 00:00:49.000 --> 00:00:52.799 energy washes over the Earth. It's perfectly timed. It's incredibly powerful, 14 00:00:53.039 --> 00:00:55.560 and it is utterly invisible to the naked. 15 00:00:55.320 --> 00:00:57.320 Eye, completely invisible, and for. 16 00:00:57.240 --> 00:01:02.200 Decades, the absolute smartest astrophisms in the world had well, 17 00:01:02.280 --> 00:01:05.400 they had absolutely no idea what was setting off this timer. 18 00:01:05.159 --> 00:01:08.519 None at all. It really is one of the most 19 00:01:09.200 --> 00:01:11.959 I guess, eerie pictures in modern astronomy. You have these 20 00:01:11.959 --> 00:01:15.200 phenomenal bursts of energy just rhythmically pulsing out of the 21 00:01:15.239 --> 00:01:18.879 absolute dark like clockwork exactly, and we're picking up the signal. 22 00:01:19.000 --> 00:01:21.239 You know, we know something enormous is out there generating it, 23 00:01:21.359 --> 00:01:23.760 but the actual mechanism behind it has just remained this 24 00:01:23.879 --> 00:01:25.280 complete void in our understanding. 25 00:01:25.400 --> 00:01:28.959 Well, our mission today is to finally unravel that exact mystery. 26 00:01:29.519 --> 00:01:34.159 We're going to explore what astronomers call long period transience 27 00:01:34.599 --> 00:01:37.760 or lpts, right, and we're going to look at this 28 00:01:37.920 --> 00:01:42.920 truly ground breaking new discovery. It's a specific star system 29 00:01:42.959 --> 00:01:45.879 designated a scott O J seventeen forty five. 30 00:01:45.959 --> 00:01:47.799 Yeah, quite a cashy name, right, Oh. 31 00:01:47.640 --> 00:01:50.040 They always have the best names in astronomy. But this 32 00:01:50.280 --> 00:01:54.400 single newly mapped system is finally giving the scientific community 33 00:01:54.439 --> 00:01:56.959 the answers they've been so desperately searching for. 34 00:01:57.200 --> 00:01:59.040 It's changing everything, honestly. 35 00:01:58.640 --> 00:02:01.959 Okay, let's unpack this because to understand why this new 36 00:02:02.000 --> 00:02:05.280 discovery is so revolutionary, we first have to look at 37 00:02:05.280 --> 00:02:08.439 how these signals behave in the wild, right, Like, why 38 00:02:08.479 --> 00:02:10.680 are they so incredibly difficult to track down in the 39 00:02:10.719 --> 00:02:11.280 first place. 40 00:02:11.599 --> 00:02:14.479 So when we talk about a transient in astronomy, we 41 00:02:14.560 --> 00:02:18.360 are generally talking about, well, anything the sky that changes 42 00:02:18.360 --> 00:02:19.520 over a short human time. 43 00:02:19.400 --> 00:02:21.120 Scarce s meaning what exactly like a. 44 00:02:21.080 --> 00:02:24.199 Star exploding, a comet passing by, maybe a solar flare, 45 00:02:24.319 --> 00:02:27.479 just something that happens relatively quickly, but a long period 46 00:02:27.560 --> 00:02:31.759 transient in this specific context refers to objects that produce 47 00:02:31.840 --> 00:02:36.360 these bright, repeating bursts of light, specifically at radio wavelengths. 48 00:02:36.400 --> 00:02:37.120 Okay, I got it. 49 00:02:37.280 --> 00:02:40.400 Now, the universe is, you know, it's a noisy, flashy place. 50 00:02:40.680 --> 00:02:43.120 They are actually quite used to things bursting in space. 51 00:02:43.000 --> 00:02:45.520 Right, Things blow up all the time exactly. 52 00:02:45.680 --> 00:02:49.599 But the timing of these specific lpts is what makes 53 00:02:49.639 --> 00:02:53.159 them such an absolute anomaly. Usually, when we find fast 54 00:02:53.240 --> 00:02:57.759 flashing objects, they repeat very rapidly, like how we're talking 55 00:02:57.759 --> 00:03:01.759 fractions of a second. These objects they operate on a 56 00:03:01.800 --> 00:03:07.879 completely different, almost languid timescale. They repeat on the order 57 00:03:07.919 --> 00:03:10.199 of minutes or sometimes even hours. 58 00:03:10.080 --> 00:03:12.039 Which I mean, if you think about the sheer amount 59 00:03:12.080 --> 00:03:15.240 of energy required to send a signal across the entire galaxy, 60 00:03:15.319 --> 00:03:17.639 a twenty minute gap feels like an eternity. 61 00:03:17.719 --> 00:03:20.280 Oh, it is an absolute eternity in high energy physics, 62 00:03:20.800 --> 00:03:25.000 and their behavior is wildly inconsistent. Too inconsistent how well, 63 00:03:25.000 --> 00:03:26.520 as you mentioned at the beginning, we have some of 64 00:03:26.520 --> 00:03:29.360 these lpts that have been pulsing with this perfect, unbroken 65 00:03:29.439 --> 00:03:33.800 rhythm for over three decades, just NonStop, relentless, a totally 66 00:03:33.840 --> 00:03:36.319 reliable beat. But then you have other transients in this 67 00:03:36.439 --> 00:03:39.520 exact same category that will pulse rhythmically for a while 68 00:03:39.919 --> 00:03:43.439 and then just well go completely dark for days at a. 69 00:03:43.400 --> 00:03:45.479 Time, just nothing, no signal at all. 70 00:03:45.479 --> 00:03:49.479 Nothing, and some go permanently radio silent. It's as if 71 00:03:49.520 --> 00:03:52.759 the engine just flooded and shut down foreverythingh that's frustrating. 72 00:03:52.800 --> 00:03:56.080 And to make matters even more complicated, almost all of 73 00:03:56.120 --> 00:03:58.520 these lpts have been discovered right in the middle of 74 00:03:58.560 --> 00:04:00.919 the Milky Way, right like close to the galactic center, 75 00:04:01.120 --> 00:04:04.520 which is essentially a massive cosmic smog bank. 76 00:04:05.039 --> 00:04:07.400 That is honestly the perfect way to describe it. It's 77 00:04:07.400 --> 00:04:09.759 a smog bank. The center of our galaxy is just 78 00:04:09.879 --> 00:04:14.599 packed with these dense clouds of gas, interstellar dust, carbon, 79 00:04:14.719 --> 00:04:15.560 silicate's ice. 80 00:04:15.719 --> 00:04:17.920 So it's just filthy out there, it really is. 81 00:04:18.360 --> 00:04:21.399 And this presents a massive observational hurdle for us. You 82 00:04:21.439 --> 00:04:24.680 can't just point a standard optical telescope like the kind 83 00:04:24.720 --> 00:04:27.240 that detects visible light at the galactic center and expect 84 00:04:27.279 --> 00:04:28.279 to see what's going on. 85 00:04:28.240 --> 00:04:30.560 Because the dust acts like a physical wall to the light. 86 00:04:30.680 --> 00:04:34.160 Right. Precisely, it comes down to how different wavelengths of 87 00:04:34.240 --> 00:04:37.879 light interact with physical matter. Visible light has a relatively 88 00:04:37.920 --> 00:04:41.199 short wavelength, right, so when it hits a microscopic particle 89 00:04:41.199 --> 00:04:45.000 of cosmic dust, the light wave just scatters, It bounces 90 00:04:45.000 --> 00:04:47.920 off in a completely different direction and never actually reaches 91 00:04:47.920 --> 00:04:49.279 our telescopes. 92 00:04:48.759 --> 00:04:50.839 Which is why the center of the galaxy just looks 93 00:04:50.920 --> 00:04:52.759 dark to the naked eye exactly. 94 00:04:53.399 --> 00:04:56.720 But radio waves, they have incredibly long wavelengths. We're talking 95 00:04:56.839 --> 00:05:00.319 meters or even kilometers long. They really, oh yeah, So 96 00:05:00.360 --> 00:05:03.199 instead of hitting those tiny dust particles and scattering, the 97 00:05:03.319 --> 00:05:06.399 radio waves just they just glide right over them. They 98 00:05:06.439 --> 00:05:09.800 pass completely through the galactic smog and eventually hit our 99 00:05:09.879 --> 00:05:11.120 radio dishes here on Earth. 100 00:05:11.199 --> 00:05:14.680 Okay, So I am imagining this like trying to observe 101 00:05:14.720 --> 00:05:17.079 a street scene while standing on the roof of a 102 00:05:17.120 --> 00:05:19.839 skyscraper in a heavily smoggy city. 103 00:05:20.040 --> 00:05:21.439 Okay, I like that, right. 104 00:05:21.319 --> 00:05:23.680 So you are looking down, but you cannot see a 105 00:05:23.720 --> 00:05:27.120 single car, a single pedestrian, or even the street itself 106 00:05:27.160 --> 00:05:29.680 because the smog is completely opaque. 107 00:05:29.279 --> 00:05:31.720 Right, it's just a wall of gray exactly. 108 00:05:32.160 --> 00:05:35.800 But every twenty minutes you hear this massive booming car 109 00:05:35.839 --> 00:05:38.160 horn cutting right through the air. You know for a 110 00:05:38.240 --> 00:05:41.000 fact something huge is down there making that noise, but 111 00:05:41.079 --> 00:05:45.199 you have zero visual conformation of its shape, its color, 112 00:05:45.360 --> 00:05:47.199 or like how many wheels it has. 113 00:05:47.319 --> 00:05:51.480 What a fantastic visualization. That is exactly the dilemma. You 114 00:05:51.519 --> 00:05:53.279 only have the sound of the horn, which is our 115 00:05:53.360 --> 00:05:56.800 radio burst. Because you can't see the actual source, and 116 00:05:56.839 --> 00:06:01.600 because these births happen so infrequently, they're remarkably hard to discover. 117 00:06:01.879 --> 00:06:05.199 I'd imagine most radio telescope surveys they scan the sky 118 00:06:05.360 --> 00:06:08.240 very quickly. They look at a patches sky, record what's 119 00:06:08.279 --> 00:06:10.839 there for maybe five minutes, and then move on to 120 00:06:10.879 --> 00:06:11.480 the next patch. 121 00:06:11.560 --> 00:06:13.879 Oh, I see the problem. If you are only looking 122 00:06:13.920 --> 00:06:17.199 for five minutes and the object only pulses every twenty. 123 00:06:16.920 --> 00:06:19.680 Minutes, you're going to miss it almost every single time. 124 00:06:19.839 --> 00:06:22.000 Wow. Which explains why we. 125 00:06:21.920 --> 00:06:25.000 Know of a few of them exactly. Despite the vastness 126 00:06:25.000 --> 00:06:28.040 of the galactic Center, astronomers have only managed a catalog 127 00:06:28.360 --> 00:06:31.680 about a dozen of these strained sources to date, just twelve. 128 00:06:31.759 --> 00:06:34.720 That is a tiny number for an entire galaxy. 129 00:06:34.399 --> 00:06:37.319 It really is. And what's fascinating here is the sheer 130 00:06:37.399 --> 00:06:41.759 diversity among just those twelve objects. I mean, even within 131 00:06:41.800 --> 00:06:45.480 such a tiny sample size. Their pulse profiles, their brightness, 132 00:06:45.480 --> 00:06:49.120 their periods of silence, they're all completely different. 133 00:06:49.160 --> 00:06:50.480 They don't match, not at all. 134 00:06:50.680 --> 00:06:54.439 They don't neatly fit into a single easily identifiable category. 135 00:06:54.600 --> 00:06:56.879 So if you are an astronomer and all you have 136 00:06:57.000 --> 00:06:59.639 is the booming horn and the smog, how do you 137 00:06:59.680 --> 00:07:02.120 even be begin to guess what's making the noise? I 138 00:07:02.160 --> 00:07:03.759 mean you have to look at the vehicles you already 139 00:07:03.759 --> 00:07:04.480 know about, right. 140 00:07:04.439 --> 00:07:07.439 You start with the usual suspects. Yeah, when you only 141 00:07:07.480 --> 00:07:10.319 have repeating radio pulses to go on, you have to 142 00:07:10.360 --> 00:07:14.319 ask the fundamental question, what else in the universe produces 143 00:07:14.360 --> 00:07:15.480 repeating radio bursts? 144 00:07:15.560 --> 00:07:17.120 Okay? And what does well? 145 00:07:17.319 --> 00:07:21.600 For decades, the absolute undisputed king of the repeating radio 146 00:07:21.639 --> 00:07:24.759 burst has been the pulsar. So the initial rating theory, 147 00:07:24.800 --> 00:07:26.959 the assumption that drove a lot of the early research, 148 00:07:27.319 --> 00:07:29.839 was that these lpts were simply pulsars that were just 149 00:07:29.879 --> 00:07:31.399 spinning very very slowly. 150 00:07:31.600 --> 00:07:34.399 Okay, let's look at the pulsar theory, because my understanding 151 00:07:34.399 --> 00:07:37.160 is that pulsars are some of the most extreme objects 152 00:07:37.199 --> 00:07:39.160 in existence. Like they aren't normal. 153 00:07:38.879 --> 00:07:43.480 Stars, oh far from it. A pulsar is a highly magnetized, 154 00:07:43.600 --> 00:07:44.920 rotating neutron. 155 00:07:44.560 --> 00:07:47.079 Star, and a neutron star is well. 156 00:07:47.199 --> 00:07:49.560 To understand what that means, we have to look at 157 00:07:49.600 --> 00:07:53.639 how a massive star dies. When a star much much 158 00:07:53.759 --> 00:07:56.480 larger than our Sun burns through all its nuclear fuel, 159 00:07:56.879 --> 00:07:59.160 it can no longer support its own weight against the 160 00:07:59.199 --> 00:08:03.240 crushing force of gravity, so it collapses violently. The core 161 00:08:03.279 --> 00:08:05.839 collapses inward in a fraction of a second, and the 162 00:08:05.879 --> 00:08:09.240 outer layers are just blown away in a massive supernova explosion. 163 00:08:09.480 --> 00:08:12.160 And what's left behind in the absolute center of that 164 00:08:12.240 --> 00:08:14.079 explosion is the neutron star. 165 00:08:14.360 --> 00:08:17.920 Yes, and it is dense. You take a mass roughly 166 00:08:18.000 --> 00:08:20.839 equivalent to our entire Sun, and you crush it down 167 00:08:20.839 --> 00:08:23.680 into a sphere about the size of a small city, like. 168 00:08:23.680 --> 00:08:26.480 The city like twenty kilometers across me exactly. 169 00:08:26.560 --> 00:08:29.759 The density is just incomprehensible to the human brain. A 170 00:08:29.759 --> 00:08:33.600 single teaspoon of neutron star material would weigh billions of tons. 171 00:08:33.639 --> 00:08:35.279 That's insane, and because of. 172 00:08:35.279 --> 00:08:38.159 The conservation of angular momentum, you know, much like an 173 00:08:38.200 --> 00:08:40.519 ice skater pulling their arms in to spin faster. 174 00:08:40.679 --> 00:08:42.559 Right, They pull their arms in and suddenly they're a blur. 175 00:08:42.960 --> 00:08:46.840 Yes, exactly, because this massive core collapse down so drastically, 176 00:08:47.440 --> 00:08:51.919 this tiny, ultra dense sphere is rotating at staggering. 177 00:08:51.399 --> 00:08:55.639 Speeds, and that rotation is what creates the lighthouse effect 178 00:08:55.679 --> 00:08:56.480 we see from Earth roax. 179 00:08:56.559 --> 00:09:00.360 Right, these neutron stars have intensely powerful magnetic flare fields. 180 00:09:01.200 --> 00:09:04.960 As they spin, they funnel charge particles to their magnetic poles, 181 00:09:05.399 --> 00:09:08.200 accelerating them to near the speed of light and blasting 182 00:09:08.240 --> 00:09:10.360 out twin beams of radio waves. 183 00:09:10.399 --> 00:09:13.159 So it's shooting out beams from the top and bottom essentially. 184 00:09:13.240 --> 00:09:16.799 Yeah, And if the star's magnetic axis is tilted relative 185 00:09:16.840 --> 00:09:20.559 to its actual rotation, those beams sweep through space like 186 00:09:20.600 --> 00:09:22.759 the beam of a lighthouse. Oh I fall, So every 187 00:09:22.759 --> 00:09:25.840 time that beam sweeps across the Earth, a radio telescope 188 00:09:25.840 --> 00:09:27.639 picks up a pulse that is your pulsar. 189 00:09:27.720 --> 00:09:30.080 Okay, but here is where I see the physical contradition 190 00:09:30.159 --> 00:09:32.840 with the theory. You mentioned that an ice skater pulls 191 00:09:32.879 --> 00:09:35.879 their arms in to spin faster, So a newly born 192 00:09:35.919 --> 00:09:38.480 pulsar should be spinning at a dizzying speed, right, like 193 00:09:39.159 --> 00:09:40.200 multiple times a second. 194 00:09:40.240 --> 00:09:40.320 Oh. 195 00:09:40.360 --> 00:09:44.000 Absolutely, A typical pulsar rotates anywhere from once every few 196 00:09:44.039 --> 00:09:47.320 seconds to hundreds of times a second. Yeah. The crab pulsar, 197 00:09:47.399 --> 00:09:49.480 for example, rotates about thirty times a second. 198 00:09:49.799 --> 00:09:52.120 But the signals we are picking up from these long 199 00:09:52.159 --> 00:09:56.120 period transients they repeat every twenty minutes. If the light 200 00:09:56.159 --> 00:09:58.440 pulse is directly tied to the spin of the star, 201 00:09:58.919 --> 00:10:01.399 that means the star is to twenty full minutes to 202 00:10:01.440 --> 00:10:02.799 complete a single rotation. 203 00:10:03.080 --> 00:10:06.879 Yes, and you have isolated the exact flaw in the 204 00:10:06.919 --> 00:10:09.639 assumption right there. The math simply does not. 205 00:10:09.679 --> 00:10:11.600 Support it because it's too slow. 206 00:10:11.879 --> 00:10:15.200 It's not just that twenty minutes is unusually slow, it's 207 00:10:15.200 --> 00:10:19.000 that a twenty minute rotation completely breaks the fundamental physics 208 00:10:19.039 --> 00:10:20.360 of how a pulsar operates. 209 00:10:20.559 --> 00:10:23.519 Wait, really, why does the speed of the spin dictate 210 00:10:23.559 --> 00:10:25.879 whether the light turns on or off. Shouldn't a slow 211 00:10:25.960 --> 00:10:27.960 lighthouse still sweep a beam. 212 00:10:27.840 --> 00:10:30.720 In a mechanical lighthouse on Earth? Yes, you just turned 213 00:10:30.720 --> 00:10:32.960 the motor down. But a pulsar is at mechanical It's 214 00:10:32.960 --> 00:10:34.399 an electromagnetic engine. 215 00:10:34.519 --> 00:10:34.879 Okay. 216 00:10:35.159 --> 00:10:38.200 The radio emission is entirely powered by the rotational kinetic 217 00:10:38.320 --> 00:10:41.519 energy of the star. Itself. As the neutron star spins, 218 00:10:41.879 --> 00:10:45.399 its massive magnetic field spins with it, and that generates 219 00:10:45.399 --> 00:10:50.000 a staggering electric field that literally rips charged particles right 220 00:10:50.039 --> 00:10:51.120 off the surface of the star. 221 00:10:51.399 --> 00:10:53.440 Whoa, it pulls its own surface off. 222 00:10:53.559 --> 00:10:56.000 Yeah, and then it flings them ount into space. Yeah. 223 00:10:56.039 --> 00:11:00.960 But this entire mechanism requires an incredibly fast spin to 224 00:11:01.039 --> 00:11:02.519 generate enough voltage to do that. 225 00:11:02.799 --> 00:11:04.600 Ah, So there is a threshold, like you have to 226 00:11:04.639 --> 00:11:07.559 be spinning at least x speed to power the beam exactly. 227 00:11:07.600 --> 00:11:08.879 We call it the death line. 228 00:11:09.039 --> 00:11:11.240 The death line sounds ominous. 229 00:11:11.039 --> 00:11:14.320 It is for the pulsar. As a pulsar ages over 230 00:11:14.399 --> 00:11:17.879 millions of years, it gradually loses energy and its rotation 231 00:11:18.000 --> 00:11:22.320 slows down. As it slows, the electric voltage drops. Once 232 00:11:22.360 --> 00:11:25.519 the rotation drops below that critical speed, usually around a 233 00:11:25.519 --> 00:11:28.759 few seconds per rotation, the voltage is no longer strong 234 00:11:28.840 --> 00:11:30.080 enough to pull particles off the. 235 00:11:30.039 --> 00:11:31.879 Surface, so the engine just cuts out. 236 00:11:32.000 --> 00:11:35.960 The acceleration stops, the radio beams completely shut off, the 237 00:11:35.960 --> 00:11:40.000 engine dies. A solitary neutron star rotating once every twenty 238 00:11:40.000 --> 00:11:42.159 minutes should be well past the death line. 239 00:11:42.200 --> 00:11:42.519 Wow. 240 00:11:42.639 --> 00:11:45.720 It should be dead cold and entirely silent in the 241 00:11:45.799 --> 00:11:46.600 radio spectrum. 242 00:11:46.639 --> 00:11:49.320 Okay, so we were basically looking at an old, rusted, 243 00:11:49.600 --> 00:11:53.120 slow moving bicycle, but it was somehow producing the roaring, 244 00:11:53.240 --> 00:11:55.919 deafening engine sound of a Formula one race car. 245 00:11:56.200 --> 00:11:59.919 That is an incredibly apt analogy. Yes, we were observing 246 00:12:00.120 --> 00:12:04.759 these massive energetic radio waves that are established universally accepted 247 00:12:04.840 --> 00:12:08.720 understanding of physics says absolutely cannot exist if the source 248 00:12:08.799 --> 00:12:11.679 is just a solitary, slowing neutron star. 249 00:12:11.840 --> 00:12:14.519 But the telescope data isn't lying right like the burst 250 00:12:14.559 --> 00:12:14.919 is real. 251 00:12:15.080 --> 00:12:16.159 Burst is very real. 252 00:12:16.320 --> 00:12:19.600 So if the bicycle cannot possibly make the roaring engine 253 00:12:19.679 --> 00:12:22.200 sound on its own, I mean it just physically can't. 254 00:12:22.240 --> 00:12:24.639 It means the bicycle isn't alone. Someone else has to 255 00:12:24.679 --> 00:12:27.799 be driving right alongside it with a sports car engine bingo. 256 00:12:28.600 --> 00:12:32.679 That exact realization is what forced the entire astronomical community 257 00:12:32.720 --> 00:12:36.159 to rethink the paradigm. If a single solitary dead star 258 00:12:36.519 --> 00:12:40.120 could possibly be responsible for these massive slow bursts, we 259 00:12:40.200 --> 00:12:41.960 had to be looking at a completely different kind of 260 00:12:42.000 --> 00:12:42.919 cosmic machinery. 261 00:12:43.039 --> 00:12:45.039 And that paradigm shift is what brings us to the 262 00:12:45.080 --> 00:12:48.639 monumental discovery of this system right s gap Ja, seventeen 263 00:12:48.759 --> 00:12:49.360 forty five. 264 00:12:49.559 --> 00:12:50.320 Yes, exactly. 265 00:12:50.399 --> 00:12:52.360 Let's talk about ASKAP for a second, because this is 266 00:12:52.360 --> 00:12:54.720 the observatory that finally caught one of these things in 267 00:12:54.759 --> 00:12:55.080 the act. 268 00:12:55.240 --> 00:12:57.879 It is so s GAP stands for the Australian Square 269 00:12:57.919 --> 00:13:01.759 Kilometer Array Pathfinder. That's a healthful it is. It's an 270 00:13:01.840 --> 00:13:05.600 array of thirty six radio dish antennas spread out across 271 00:13:05.639 --> 00:13:09.519 the remote outback of Western Australia, and it's operated by CSIRO, 272 00:13:09.960 --> 00:13:11.759 which is the National science agency there. 273 00:13:11.840 --> 00:13:13.720 Okay, thirty six dishes. 274 00:13:13.440 --> 00:13:17.639 Right, Instead of one massive monolithic dish, these thirty six 275 00:13:17.720 --> 00:13:22.240 dishes work together as a single incredibly sensitive instrument through 276 00:13:22.240 --> 00:13:24.960 a process called interferometry. 277 00:13:24.200 --> 00:13:25.320 So they link them all up. 278 00:13:25.519 --> 00:13:30.039 Yes, it essentially allows astronomers to survey huge swaths of 279 00:13:30.080 --> 00:13:33.240 the sky with incredible speed and detail. 280 00:13:33.159 --> 00:13:35.720 And they use this to spot a brand new long 281 00:13:35.799 --> 00:13:37.120 period radio transient. 282 00:13:37.200 --> 00:13:40.320 They did. But you know what makes ASKAP JAY seventeen 283 00:13:40.440 --> 00:13:43.039 forty five the true turning point this entire field of 284 00:13:43.080 --> 00:13:46.039 study isn't just that they found another ticking radio source. 285 00:13:46.480 --> 00:13:49.559 It's what the astronomers did immediately after they found it. 286 00:13:49.600 --> 00:13:52.080 For the very first time, they managed to coordinate a 287 00:13:52.159 --> 00:13:55.320 massive multi wavelength observation campaign. 288 00:13:55.039 --> 00:13:58.399 Multi wavelength, meaning they didn't just use radio exactly. 289 00:13:58.440 --> 00:14:00.399 They didn't just listen to the radio waves and should 290 00:14:00.399 --> 00:14:02.799 look at the system using X ray telescopes and optical 291 00:14:02.840 --> 00:14:05.039 telescopes simultaneously, which. 292 00:14:05.279 --> 00:14:08.559 Just from a logistical standpoint has to be a monumental headache. 293 00:14:08.559 --> 00:14:10.200 I mean, you can't just walk outside your house with 294 00:14:10.279 --> 00:14:11.840 three different sets of binoculars. 295 00:14:11.879 --> 00:14:14.720 Oh, it is a phenomenal feed of coordination. I mean, 296 00:14:14.879 --> 00:14:18.080 think about what is required here. You have the radio 297 00:14:18.279 --> 00:14:22.120 array tracking the target from the ground in Australia. To 298 00:14:22.159 --> 00:14:25.840 get optical visible light data, you need to coordinate with 299 00:14:26.440 --> 00:14:31.360 massive ground based observatories, perhaps in Chile or Hawaii, and 300 00:14:31.440 --> 00:14:34.879 literally prey that the weather holds and that the target 301 00:14:34.919 --> 00:14:37.240 is above the horizon during their specific night. 302 00:14:37.320 --> 00:14:39.399 No man, the weather. I didn't even think about that. 303 00:14:39.720 --> 00:14:42.720 It ruins observations all the time. And for X rays, 304 00:14:43.080 --> 00:14:46.000 our atmosphere entirely absorbs X rays from. 305 00:14:45.919 --> 00:14:48.159 Space, which is great for human health. 306 00:14:47.960 --> 00:14:51.080 Very great for us, but it's terrible for astronomy. So 307 00:14:51.120 --> 00:14:53.720 to observe X rays you have to secure observation time 308 00:14:53.960 --> 00:14:56.600 on billion dollar space satellites orbiting the Earth. 309 00:14:56.639 --> 00:14:58.799 So uch a book satellite time too, Yeah. 310 00:14:58.600 --> 00:15:01.840 And getting all of these ainked highly demanded instruments. To 311 00:15:01.919 --> 00:15:04.799 point at the exact same microscopic coordinate in the sky 312 00:15:04.840 --> 00:15:08.320 at the exact same minute requires years of proposals and 313 00:15:08.440 --> 00:15:09.919 just a staggering amount of luck. 314 00:15:10.080 --> 00:15:13.039 But they pulled it off. They stared at the smog 315 00:15:13.159 --> 00:15:16.480 with every type of lens humanity has built. And what 316 00:15:16.519 --> 00:15:18.080 did they actually see? 317 00:15:18.399 --> 00:15:22.080 They saw the complete picture. Acecap j seventeen forty five 318 00:15:22.360 --> 00:15:25.840 wasn't just emitting radio bursts. It was emitting both radio 319 00:15:25.960 --> 00:15:26.960 and X ray. 320 00:15:26.799 --> 00:15:28.360 Bursts at the same time. 321 00:15:28.480 --> 00:15:33.679 Yes, and crucially, those bursts were repeating in absolute perfect 322 00:15:33.720 --> 00:15:36.399 synchronization with the orbital motion of the system. 323 00:15:36.480 --> 00:15:38.720 So they didn't just find a suspect. They caught it 324 00:15:38.799 --> 00:15:42.679 on multiple cameras from different angles, all time stamped. 325 00:15:42.320 --> 00:15:45.440 Exactly if we connect this to the bigger picture. The 326 00:15:45.480 --> 00:15:49.279 researchers themselves referred to this multi wavelength detection as the 327 00:15:49.440 --> 00:15:50.759 Rosetta Stone. 328 00:15:50.360 --> 00:15:52.519 Like the actual historical artifact from. 329 00:15:52.399 --> 00:15:56.879 Egypt, exactly that for centuries historians were completely paralyzed by 330 00:15:56.960 --> 00:15:58.360 ancient Egyptian hieroglyphs. 331 00:15:58.399 --> 00:15:59.559 Right, they couldn't read them at all. 332 00:15:59.679 --> 00:16:02.399 They were looking at these beautiful, intricate symbols, but they 333 00:16:02.399 --> 00:16:05.360 had absolutely no underlying framework to understand what they meant. 334 00:16:05.360 --> 00:16:08.159 It was just visual noise until the stone. 335 00:16:07.799 --> 00:16:10.759 Right, because the Rosetta Stone featured the exact same decree 336 00:16:11.200 --> 00:16:15.080 written in three distinct scripts, ancient Greek, which scholars could 337 00:16:15.080 --> 00:16:18.159 fluently read, Demotic and Egyptian. 338 00:16:17.840 --> 00:16:19.759 Hieroglyphs, so they just lined them up. 339 00:16:20.320 --> 00:16:23.600 Because the underlying message was identical across all three, they 340 00:16:23.639 --> 00:16:26.120 could finally use the Greek to crack the code of 341 00:16:26.159 --> 00:16:27.039 the hieroglyphs. 342 00:16:27.320 --> 00:16:30.200 Okay, So in this cosmic scenario, the three scripts are 343 00:16:30.440 --> 00:16:33.559 the radio waves, the X rays, and the optical visible light. 344 00:16:33.720 --> 00:16:37.039 Exactly for thirty years, these long period transients have been 345 00:16:37.080 --> 00:16:40.279 speaking exclusively in radio waves, a language that made absolutely 346 00:16:40.320 --> 00:16:43.600 no physical sense to us because the solitary pulsar math didn't. 347 00:16:43.399 --> 00:16:45.559 Work right, It was just noise we couldn't decipher. 348 00:16:45.679 --> 00:16:49.039 But now, because ascop j seventeen forty five is speaking 349 00:16:49.080 --> 00:16:52.279 in all three wavelengths spiultaneously, we can use the X 350 00:16:52.360 --> 00:16:55.200 ray and optical data to translate the radio signal. 351 00:16:55.279 --> 00:16:58.480 You've got it perfectly, and that translation allowed them to 352 00:16:58.559 --> 00:17:01.399 definitively identify the en engine. And the engine is a 353 00:17:01.519 --> 00:17:05.279 Scapja seventeen forty five is not a solitary pulsar. It 354 00:17:05.359 --> 00:17:09.960 is a cataclysmic variable, specifically in a creating white dwarf 355 00:17:10.000 --> 00:17:10.920 binary system. 356 00:17:11.000 --> 00:17:14.599 Okay, here's where it gets really interesting. We have unmasked 357 00:17:14.640 --> 00:17:17.839 the suspect. We know the engine is an accreting white 358 00:17:17.920 --> 00:17:22.599 dwarf binary, but what does that actually mean. Let's dissect 359 00:17:22.640 --> 00:17:25.680 the physical anatomy of the system, because reading about it 360 00:17:25.680 --> 00:17:27.559 it is just wild, it really is. 361 00:17:28.000 --> 00:17:29.880 So we have to look at the two distinct stars 362 00:17:29.880 --> 00:17:34.240 involved in this binary dance player. One is the white dwarf. Okay, Now, 363 00:17:34.319 --> 00:17:37.839 earlier we discussed neutron stars, which are born from the 364 00:17:37.920 --> 00:17:41.880 explosive death of massive stars. A white dwarf is also 365 00:17:42.000 --> 00:17:44.359 a dead star, but it comes from a much more 366 00:17:44.359 --> 00:17:47.880 common origin like our son. Exactly like our son, when 367 00:17:47.920 --> 00:17:49.960 a lower mass star reaches the end of its life, 368 00:17:50.119 --> 00:17:53.480 it doesn't explode in a violent supernova. It gently puffs 369 00:17:53.519 --> 00:17:56.559 off its outer layers over time, leaving behind this dense, 370 00:17:56.680 --> 00:17:59.359 intensely hot, slowly cooling core. 371 00:17:59.480 --> 00:18:01.839 And that core is the white dwarf. Yes, so it's dense, 372 00:18:01.920 --> 00:18:04.359 but not you know, a tea spoon weighing a mountain 373 00:18:04.519 --> 00:18:05.799 dense like the neutron star. 374 00:18:05.880 --> 00:18:07.799 Right, it's not quite that extreme. It has roughly the 375 00:18:07.839 --> 00:18:09.759 mass of our Sun, but it squeezed down into a 376 00:18:09.759 --> 00:18:11.160 sphere about the size of the Earth. 377 00:18:11.240 --> 00:18:12.759 Okay, so still incredibly dense. 378 00:18:13.039 --> 00:18:16.160 Oh the gravity is immense, yes, yeah, but it isn't 379 00:18:16.240 --> 00:18:20.480 governed by the extreme quantum weirdness of a neutron star. Now, 380 00:18:20.559 --> 00:18:24.160 player two in this system is a low mass red 381 00:18:24.240 --> 00:18:24.880 dwarf star. 382 00:18:25.440 --> 00:18:27.039 A red dwarf so this one isn't dead. 383 00:18:27.119 --> 00:18:30.440 No, this is a living star. It is actively fusing hydrogen. 384 00:18:30.720 --> 00:18:33.440 But it is much smaller, cooler, and dimmer than our Sun. 385 00:18:33.839 --> 00:18:37.920 So we have a dead, cooling Earth sized core and 386 00:18:38.000 --> 00:18:42.000 a living small red star. And the keyword here is binary. 387 00:18:42.319 --> 00:18:43.640 They are orbiting each. 388 00:18:43.480 --> 00:18:47.599 Other, orbiting incredibly closely, so closely in fact, that they 389 00:18:47.680 --> 00:18:51.640 cross a critical gravitational threshold known as the rochlobe the 390 00:18:51.759 --> 00:18:52.400 row schlobe. 391 00:18:52.559 --> 00:18:55.400 Okay, what happens when they cross that threshold. 392 00:18:55.079 --> 00:18:59.160 Well, it initiates a process of intense stellar theft sellar theft. 393 00:18:59.200 --> 00:19:02.119 I love that it's the most accurate term. Gravity is 394 00:19:02.200 --> 00:19:05.440 essentially a battle of mass and distance. Because these two 395 00:19:05.440 --> 00:19:08.960 stars are orbiting in such tight proximity, the gravitational pull 396 00:19:09.000 --> 00:19:10.799 of the ultra dense white dwarf on the side of 397 00:19:10.799 --> 00:19:13.119 the red dwarf facing it becomes stronger than the red 398 00:19:13.200 --> 00:19:15.200 dwarf's own ability to hold onto its gas. 399 00:19:15.279 --> 00:19:19.359 Oh wow, So it's literally overpowering the other star's gravity completely. 400 00:19:20.119 --> 00:19:24.359 The white Dwarf's gravity physically breaches the red Dwarf's atmosphere 401 00:19:24.599 --> 00:19:27.720