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 00:00:26.879 --> 00:00:29.399 I want you to picture a UFO, just you know, 8 00:00:29.480 --> 00:00:31.879 take a second and picture it in your mind. Right now. 9 00:00:31.920 --> 00:00:35.200 You're probably imagining a silver saucer exactly. 10 00:00:34.719 --> 00:00:37.039 Like a saucer hovering over some deserted highway in. 11 00:00:37.079 --> 00:00:40.320 Nevada, maybe some flashing neon lights, a humming tractor beam. 12 00:00:40.479 --> 00:00:43.240 Yeah, the classic Little Green Men stepping out of a ramp. 13 00:00:43.960 --> 00:00:47.159 But we are actually redefining that acronym today for this 14 00:00:47.280 --> 00:00:47.840 deep dive. 15 00:00:48.039 --> 00:00:51.119 It's a phenomenal rebranding, honestly, it really is. 16 00:00:51.640 --> 00:00:54.600 We are taking the idea of a UFO, stripping away 17 00:00:54.600 --> 00:00:57.439 all those sci fi tropes and replacing it with something 18 00:00:57.560 --> 00:00:59.479 infinitely more terrifying. 19 00:00:59.039 --> 00:01:02.399 And I mean infinitely more fascinating too. We are trading 20 00:01:02.439 --> 00:01:05.200 flying saucers for ultrafast. 21 00:01:04.439 --> 00:01:09.280 Outflows, ultrafast outflows, so we aren't talking about aliens visiting Earth. 22 00:01:09.680 --> 00:01:14.400 We are talking about a mechanism so incomprehensibly powerful that 23 00:01:14.480 --> 00:01:17.400 it could literally shut down the birth of stars across 24 00:01:17.400 --> 00:01:18.640 an entire galaxy. 25 00:01:18.760 --> 00:01:21.560 Right, It's a cosmic event that basically dictates the life 26 00:01:21.599 --> 00:01:24.840 and death of the universe's most massive structures and. 27 00:01:24.760 --> 00:01:27.599 Our destination for this exploration. The place we're looking at 28 00:01:27.640 --> 00:01:31.280 today is a hyper luminous quasar sitting deep in the 29 00:01:31.359 --> 00:01:32.200 universe's past. 30 00:01:32.560 --> 00:01:35.280 Yeah, it has this catalog designation that sounds a bit 31 00:01:35.400 --> 00:01:36.280 like a secret code. 32 00:01:36.599 --> 00:01:39.840 Any saha is thirteen LASH thirteen. It sounds like a 33 00:01:39.840 --> 00:01:43.079 license plate, but it's actually the key to a massive 34 00:01:43.159 --> 00:01:44.359 astronomical mystery. 35 00:01:44.439 --> 00:01:47.840 Well, when we look at WISH thirteen, we are essentially 36 00:01:47.879 --> 00:01:51.040 looking at the cosmos as it was billions of years ago. 37 00:01:51.280 --> 00:01:53.959 It's during this period of extreme galactic. 38 00:01:53.480 --> 00:01:56.680 Construction, right, But what we find there challenges a lot 39 00:01:56.719 --> 00:01:59.920 of basic assumptions we have about the universe. It really does, 40 00:02:00.439 --> 00:02:02.200 and that brings us to the core mystery we are 41 00:02:02.280 --> 00:02:05.200 unpacking for you today, Because think about it. When you 42 00:02:05.239 --> 00:02:09.800 think of a super massive black hole, the immediate image is, well, 43 00:02:09.879 --> 00:02:12.080 the ultimate cosmic vacuum cleaner, an. 44 00:02:11.919 --> 00:02:15.400 Object famous for consuming absolutely everything that crosses its event 45 00:02:15.439 --> 00:02:16.840 horizon exactly. 46 00:02:16.639 --> 00:02:19.400 Not even light escapes. So how does an object define 47 00:02:19.560 --> 00:02:22.800 entirely by its ability to eat everything end up blasting 48 00:02:22.800 --> 00:02:26.080 away enough matter to shape the evolution of its host galaxy. 49 00:02:26.199 --> 00:02:27.879 It's completely counterintuitive. 50 00:02:28.000 --> 00:02:31.840 It is how does the ultimate consumer become the ultimate disruptor? 51 00:02:32.199 --> 00:02:35.919 That exact paradox is at the heart of modern astrophysics. 52 00:02:36.120 --> 00:02:39.319 We are looking at the very mechanics of cosmic regulation here, 53 00:02:39.759 --> 00:02:43.080 and the goal is to explore how astronomers are actually 54 00:02:43.120 --> 00:02:47.080 managing to decode these invisible winds winds of plasma. Yeah, 55 00:02:47.120 --> 00:02:50.039 winds of plasma moving at a significant fraction of the 56 00:02:50.080 --> 00:02:53.080 speed of light. And you know what the structure of 57 00:02:53.120 --> 00:02:56.000 those winds tells us about the delicate balance of power 58 00:02:56.000 --> 00:02:56.719 in the universe. 59 00:02:57.199 --> 00:03:00.560 So let's set the scene. We're looking at this luminous 60 00:03:00.719 --> 00:03:06.240 quasar WISSH thirteen, and the data places it at a 61 00:03:06.280 --> 00:03:09.039 redshift of three point two ninety four. 62 00:03:08.879 --> 00:03:11.199 Which is a very specific, very important number. 63 00:03:11.400 --> 00:03:14.800 Right now, for anyone listening who tracks early universe astronomy, 64 00:03:15.319 --> 00:03:18.199 you know that specific number drops it right smack in 65 00:03:18.240 --> 00:03:20.000 the middle of an era known as cosmic noon. 66 00:03:20.240 --> 00:03:23.199 We are talking roughly one point six to three point 67 00:03:23.240 --> 00:03:25.280 five billion years after the Big Bang. 68 00:03:25.520 --> 00:03:27.840 Let's pause on that redshift number for a second, because 69 00:03:27.879 --> 00:03:29.919 the mechanics of how we even know when this is 70 00:03:29.919 --> 00:03:33.240 happening is just it's fascinating. 71 00:03:32.639 --> 00:03:34.919 To me, it really is. Redshift isn't just a distance 72 00:03:34.960 --> 00:03:37.240 marker on a cosmic highway. It's actually a measure of 73 00:03:37.240 --> 00:03:39.759 how much the universe has stretched while the light was 74 00:03:39.759 --> 00:03:43.199 in transit. Yeah, when the black hole at the center 75 00:03:43.240 --> 00:03:48.159 of Wish thirteen emitted this X ray light, those photons 76 00:03:48.240 --> 00:03:51.599 began a journey across the universe towards us. But the 77 00:03:51.719 --> 00:03:53.000 universe isn't static. 78 00:03:53.319 --> 00:03:55.599 Space time is actively expanded exactly. 79 00:03:55.680 --> 00:03:56.879 Space time is stretching. 80 00:03:57.240 --> 00:04:00.479 So as the space between that quasar and our telescope wretches, 81 00:04:01.120 --> 00:04:03.919 the actual waves of light are being physically stretched out 82 00:04:03.960 --> 00:04:04.560 along with it. 83 00:04:04.680 --> 00:04:07.560 They are the literal wavelengths get longer. 84 00:04:07.680 --> 00:04:08.000 Wow. 85 00:04:08.159 --> 00:04:11.360 So if you have a highly energetic, tightly packed X 86 00:04:11.439 --> 00:04:14.039 ray wave and you stretch it out over a journey 87 00:04:14.039 --> 00:04:17.680 of ten billion years, it's wavelength shifts toward the red 88 00:04:17.759 --> 00:04:19.439 end of the electromagnetic spectrum. 89 00:04:19.680 --> 00:04:21.319 In shredshift, right, a. 90 00:04:21.240 --> 00:04:23.399 Red shift of three point two ninety four means the 91 00:04:23.480 --> 00:04:26.000 universe has expanded by more than a factor of four 92 00:04:26.199 --> 00:04:27.639 since that light left the Koisar. 93 00:04:27.920 --> 00:04:29.920 That's I mean, that's almost hard to wrap your head around. 94 00:04:30.000 --> 00:04:32.079 It is, so we aren't just looking far away. We 95 00:04:32.120 --> 00:04:35.120 are looking at an incredibly specific, chaotic epoch in the 96 00:04:35.160 --> 00:04:36.480 history of everything. 97 00:04:36.160 --> 00:04:38.680 Cosmic Noon. I always think of that era as like 98 00:04:38.759 --> 00:04:40.639 the Roaring twenties of the cosmos. 99 00:04:40.839 --> 00:04:43.160 That's a really apt description. If you map out the 100 00:04:43.199 --> 00:04:45.879 star formation history of the universe, Cosmic Noon is. 101 00:04:45.800 --> 00:04:47.800 The absolute peak everyone was partying. 102 00:04:47.879 --> 00:04:53.040 Basically, Yeah, galaxies were colliding constantly, Colossal reservoirs of cold 103 00:04:53.079 --> 00:04:56.839 gas were flowing along these giant cosmic filaments, and. 104 00:04:56.800 --> 00:04:59.920 At the centers of these developing galaxies, super massive bla 105 00:05:00.000 --> 00:05:02.199 black holes were feasting. 106 00:05:02.040 --> 00:05:06.399 Gorging themselves. Really, the environment was dense and incredibly violent. 107 00:05:06.319 --> 00:05:09.040 And the black hole at the center of Toyoa Ssh 108 00:05:09.120 --> 00:05:13.240 thirteen is a monster even by those standards. Oh. Absolutely, 109 00:05:13.360 --> 00:05:15.959 we are talking about a central mass of roughly two 110 00:05:16.040 --> 00:05:19.000 billion solar masses two billion. 111 00:05:18.680 --> 00:05:20.279 Two billion times the weight of our Sun. 112 00:05:21.199 --> 00:05:24.560 Because we are in cosmic Noon, surrounded by all this 113 00:05:24.680 --> 00:05:28.439 raw material, this specific black hole is feeding at an 114 00:05:28.439 --> 00:05:29.240 exceptional rate. 115 00:05:29.600 --> 00:05:32.959 But here's where the mechanics of black holes always trip people. 116 00:05:32.800 --> 00:05:34.720 Up a little bit, right, because we talk about a 117 00:05:34.759 --> 00:05:37.839 black hole feeding, but observationally what we actually see is 118 00:05:37.839 --> 00:05:41.600 its shining exactly and Wickly SSH thirteen isn't just shining, 119 00:05:41.680 --> 00:05:44.839 It is shining about three times brighter than astronomers would 120 00:05:44.839 --> 00:05:47.879 normally expect for a black hole. This staggering size. 121 00:05:47.560 --> 00:05:50.000 Which forces us to look really closely at the physics 122 00:05:50.000 --> 00:05:51.399 of the accretion disc, the. 123 00:05:51.360 --> 00:05:53.079 Disc and materials swirling around it. 124 00:05:53.240 --> 00:05:57.399 Right, The black hole itself, the singularity past the event horizon, 125 00:05:57.879 --> 00:06:02.839 emits no light. It's invisible black, yes, But the environment 126 00:06:02.920 --> 00:06:06.600 immediately surrounding it is the brightest continuous light source in 127 00:06:06.639 --> 00:06:07.279 the universe. 128 00:06:07.680 --> 00:06:10.839 Because when a black hole's gravity pulls in massive amounts 129 00:06:10.879 --> 00:06:14.800 of gas and dust, that material doesn't just fall straight down, 130 00:06:15.040 --> 00:06:15.399 does it. 131 00:06:15.839 --> 00:06:18.480 No, It has angular momentum. 132 00:06:17.839 --> 00:06:19.120 Like water circling a drain. 133 00:06:19.399 --> 00:06:23.319 Exactly. It's swirling inward, forming a flattened disk, but it's 134 00:06:23.439 --> 00:06:24.959 not a gentle swirl. 135 00:06:25.160 --> 00:06:25.399 Right. 136 00:06:25.560 --> 00:06:28.839 The material in the inner regions of that accretion disk 137 00:06:29.000 --> 00:06:32.839 is orbiting much much faster than the material on the outer. 138 00:06:32.759 --> 00:06:34.839 Edges because it's closer to the gravity source. 139 00:06:35.040 --> 00:06:38.600 Right, and this differential rotation creates immense friction. You have 140 00:06:38.800 --> 00:06:42.920 billions of tons of gas crowding together, shearing against itself. Wow, 141 00:06:43.079 --> 00:06:46.120 and it's moving at speeds approaching the speed of light, and. 142 00:06:46.240 --> 00:06:49.720 Friction generates heat. But we aren't talking about rubbing your 143 00:06:49.759 --> 00:06:51.800 hands together on a cold day, not at all. We 144 00:06:51.839 --> 00:06:55.279 are talking about thermal energy so intense that it literally 145 00:06:55.319 --> 00:06:56.720 breaks the bonds of atoms. 146 00:06:57.000 --> 00:07:00.759 The temperature sore into the millions, even ten of millions 147 00:07:00.800 --> 00:07:01.360 of degrees. 148 00:07:01.839 --> 00:07:03.079 That's unimaginable. 149 00:07:03.160 --> 00:07:06.600 It is the gas is completely ionized into a plasma, 150 00:07:07.000 --> 00:07:11.240 and that superheated plasma radiates intense energy, predominantly in X 151 00:07:11.319 --> 00:07:12.439 rays and ultraviolet light. 152 00:07:12.600 --> 00:07:16.600 Okay, so when we measure the luminosity of w ISS thirteen, 153 00:07:17.240 --> 00:07:21.560 we are basically measuring this frantic, superheated traffic jam of. 154 00:07:21.560 --> 00:07:25.920 Matter, exactly matter desperately trying to squeeze through the bottleneck 155 00:07:25.920 --> 00:07:26.959 of the event horizon. 156 00:07:27.040 --> 00:07:29.160 It's like a messi eater at a buffet trying to 157 00:07:29.160 --> 00:07:30.800 shove so much food in their mouth that it's just 158 00:07:30.879 --> 00:07:34.240 flying everywhere, generating all this energy just outside the event horizon. 159 00:07:34.319 --> 00:07:35.600 That's a great way to picture it. 160 00:07:35.639 --> 00:07:39.120 But wait, if this supermassive black hole has two billion 161 00:07:39.319 --> 00:07:44.319 solar masses. Its gravitational pole is almost unfathomable, and it's 162 00:07:44.360 --> 00:07:47.560 surrounded by this all you can eat buffet of galactic gas. 163 00:07:48.319 --> 00:07:50.560 If it's gravity's that strong, why doesn't it just swallow 164 00:07:50.560 --> 00:07:51.800 the entire host galaxy? 165 00:07:51.920 --> 00:07:52.879 That's the big question. 166 00:07:53.160 --> 00:07:55.879 What stops this from turning into a runaway scenario where 167 00:07:55.879 --> 00:07:59.399 the black hole just consumes everything until there's nothing left 168 00:07:59.439 --> 00:08:00.639 but the black hole itself. 169 00:08:00.680 --> 00:08:05.000 Well, that very question plagued theoretical physicists for years. Yeah, 170 00:08:05.399 --> 00:08:07.519 if you just run the raw math on gravity and 171 00:08:07.600 --> 00:08:10.759 gas density in the early universe, galaxies should have grown 172 00:08:10.839 --> 00:08:11.680 much larger than. 173 00:08:11.560 --> 00:08:14.839 They actually are because there was so much material exactly. 174 00:08:14.600 --> 00:08:17.639 And black holes should have eaten vastly more material. There 175 00:08:17.639 --> 00:08:19.399 had to be a mechanism that halted. 176 00:08:19.120 --> 00:08:22.199 The growth, something that chokes off the food supply, right. 177 00:08:22.319 --> 00:08:26.480 And that brings us back to the ultrafast outflows the UFOs. 178 00:08:26.000 --> 00:08:29.000 The universe's thermostat exactly. Okay, let's look at how this 179 00:08:29.040 --> 00:08:32.240 thermistat actually functions for you listening, Because the survival of 180 00:08:32.279 --> 00:08:35.720 the entire galaxy depends on it, How does blowing gas 181 00:08:35.759 --> 00:08:38.440 away act as a regulatory system? 182 00:08:38.639 --> 00:08:40.799 It relies on a critical feedback loop, and it all 183 00:08:40.799 --> 00:08:43.440 comes down to the thermal state of the galaxy's gas 184 00:08:43.759 --> 00:08:44.440 to temperature. 185 00:08:44.559 --> 00:08:44.720 Right. 186 00:08:44.879 --> 00:08:47.840 To build a galaxy, you need to form stars. To 187 00:08:47.919 --> 00:08:51.159 form a star, you need a massive, dense cloud of 188 00:08:51.279 --> 00:08:55.600 molecular gas. But here is the absolute strictest rule of 189 00:08:55.600 --> 00:08:59.320 star formation. That gas must be incredibly cold. 190 00:08:59.480 --> 00:09:02.799 This is when those rules that feel so counterintuitive. We 191 00:09:02.840 --> 00:09:06.039 associate stars with immense heat and fusion, but their actual 192 00:09:06.159 --> 00:09:08.399 birth requires freezing temperatures. 193 00:09:08.720 --> 00:09:11.639 Yes, and that's because of the constant battle between gravity 194 00:09:11.639 --> 00:09:12.480 and thermal pressure. 195 00:09:12.639 --> 00:09:12.759 Right. 196 00:09:12.879 --> 00:09:15.799 If a cloud of gas is hot, the individual particles 197 00:09:15.799 --> 00:09:20.320 are highly energetic. They are vibrating, colliding, pushing outwards like steam, 198 00:09:20.360 --> 00:09:25.120 expanding exactly that outward thermal pressure easily overpowers the inward 199 00:09:25.120 --> 00:09:28.919 pull of gravity. The cloud simply expands and dissipates. 200 00:09:29.159 --> 00:09:32.480 It won't collapse, so gravity needs an unfair advantage to win. 201 00:09:32.759 --> 00:09:35.919 Precisely, the gas must tool down to just a few 202 00:09:35.960 --> 00:09:39.559 degrees above absolute zero, which is freezing beyond freezing. And 203 00:09:39.600 --> 00:09:43.080 when the gas is that sluggish, the thermal pressure drops 204 00:09:43.120 --> 00:09:43.799 to near. 205 00:09:43.720 --> 00:09:45.480 Zero and gravity takes over. 206 00:09:45.639 --> 00:09:48.840 Right, Gravity takes over, pulling the cloud together until the 207 00:09:48.840 --> 00:09:51.360 core becomes dense enough to ignite nuclear fusion. 208 00:09:51.720 --> 00:09:54.440 So cold gas equals star formation. 209 00:09:54.360 --> 00:09:56.399 And hot gas equals a dead galaxy. 210 00:09:56.600 --> 00:09:59.320 Wow. Okay, Now let's introduce the black holes killer wind 211 00:09:59.679 --> 00:10:00.440 the eu UFO. 212 00:10:00.799 --> 00:10:03.360 So the black hole is gorging itself, the accretion disc 213 00:10:03.440 --> 00:10:07.080 is blazing hot, and the intense radiation, pressure and magnetic 214 00:10:07.080 --> 00:10:10.879 fields generated in that disc actually start driving material outward. 215 00:10:11.240 --> 00:10:14.039 It's like the black hole is feeding so aggressively that 216 00:10:14.080 --> 00:10:16.279 it pushes its own food away exactly. 217 00:10:16.679 --> 00:10:20.240 And when these winds achieve velocities exceeding ten percent of 218 00:10:20.279 --> 00:10:23.399 the speed of light, they become ultrafast outflows. 219 00:10:23.600 --> 00:10:27.240 And these winds aren't just empty space, right, They carry 220 00:10:27.440 --> 00:10:30.440 unimaginably huge amounts of kinetic energy. 221 00:10:30.639 --> 00:10:34.600 Immense kinetic energy. When a wind moving at a fraction 222 00:10:34.679 --> 00:10:37.840 of light speeds slams into the surrounding ambient gas of 223 00:10:37.879 --> 00:10:41.000 the host galaxy, the collision is catastrophic. 224 00:10:41.200 --> 00:10:41.960 I can imagine. 225 00:10:42.000 --> 00:10:45.080 It creates massive shock waves. It acts like a cosmic 226 00:10:45.080 --> 00:10:48.679 blow torch, transferring all that kinetic energy into thermal energy. 227 00:10:48.840 --> 00:10:51.200 Oh. I see, So the ambient gas in the galaxy 228 00:10:51.279 --> 00:10:53.200 is suddenly heated up to millions of degrees. 229 00:10:53.320 --> 00:10:57.120 Right, And because the gas is now superheated, the thermal pressure. 230 00:10:56.720 --> 00:10:59.639 Spikes, and gravity loses the battle exactly. 231 00:10:59.440 --> 00:11:02.399 The gas it can't collapse into molecular clouds, which means 232 00:11:02.399 --> 00:11:03.840 it can't form stars. 233 00:11:04.159 --> 00:11:06.879 So the UFO effectively quenches the galaxy. 234 00:11:06.960 --> 00:11:10.120 It does if the wind is powerful enough and sustained 235 00:11:10.159 --> 00:11:12.960 over a long enough period, it will either heat the 236 00:11:13.000 --> 00:11:17.039 gas so thoroughly that star formation permanently shuts down, or 237 00:11:17.120 --> 00:11:20.480 it will literally sweep the gas entirely out of the 238 00:11:20.519 --> 00:11:25.080 galaxy's gravitational well, just blowing it into intergalactic. 239 00:11:24.320 --> 00:11:29.240 Space, just emptying the cupboards. Think about the philosophical implication 240 00:11:29.320 --> 00:11:31.639 of that for a second. The deep. If you are 241 00:11:31.639 --> 00:11:34.440 listening to this, you likely grew up learning that black 242 00:11:34.440 --> 00:11:36.960 holes are the ultimate symbol of destruction. 243 00:11:36.720 --> 00:11:38.360 The greater rasers of the universe. 244 00:11:38.519 --> 00:11:41.240 Right. They are the void that crushes matter out of existence. 245 00:11:42.440 --> 00:11:46.559 But functionally, within the mechanics of a galaxy, the black 246 00:11:46.559 --> 00:11:49.759 hole is the regulator it is. It dictates the life 247 00:11:49.759 --> 00:11:53.600 cycle of stars, It regulates its own massive growth by 248 00:11:53.679 --> 00:11:57.039 violently blowing its food source away, and in doing so, 249 00:11:57.559 --> 00:12:00.600 it freezes the host galaxy's ability to grow any further. 250 00:12:00.720 --> 00:12:05.039 It's an incredibly elegant, albeit violent symmetry elegantly violin. I 251 00:12:05.080 --> 00:12:09.000 like that because without these relativistic winds, galaxies during cosmic 252 00:12:09.080 --> 00:12:11.720 noon might have just converted all their available gas into 253 00:12:11.799 --> 00:12:14.879 stars in one massive, uncontrolled burst. 254 00:12:14.879 --> 00:12:17.320 And black holes would have swelled to impossible proportions. 255 00:12:17.399 --> 00:12:20.080 Right, the universe would look fundamentally different today. 256 00:12:20.240 --> 00:12:23.159 So it really is a thermostat. The galaxy gets too hot, 257 00:12:23.200 --> 00:12:26.080 meaning the central black hole is feeding too rapidly, and 258 00:12:26.120 --> 00:12:30.519 the system triggers a cooling mechanism, Except the cooling mechanism 259 00:12:30.799 --> 00:12:35.000 is a lethal gale of highly ionized plasma that shuts 260 00:12:35.000 --> 00:12:36.559 down the factory entirely. 261 00:12:36.480 --> 00:12:39.799 A self correcting system operating on a scale of hundreds 262 00:12:39.799 --> 00:12:40.879 of thousands of white years. 263 00:12:40.919 --> 00:12:43.600 Okay, the mechanical logic of the thermostat makes perfect sense. 264 00:12:44.159 --> 00:12:47.960 The black hole eats, the disc gets chaotic, radiation pressure 265 00:12:48.080 --> 00:12:51.240 drives the winds outward. The kinetic energy shocks the host 266 00:12:51.320 --> 00:12:54.600 galaxies gas, it heats up, star formation dies. 267 00:12:54.720 --> 00:12:55.519 That's the sequence. 268 00:12:55.919 --> 00:12:58.080 But here is where my mind starts to bend. And 269 00:12:58.120 --> 00:13:00.399 I know anyone listening who understand that the vast fastness 270 00:13:00.440 --> 00:13:03.159 of space is probably wondering the exact same thing. 271 00:13:03.240 --> 00:13:04.440 How do we actually see it. 272 00:13:04.639 --> 00:13:09.279 Yes, WISSH thirteen is at redshift three point twenty ninety four. 273 00:13:09.919 --> 00:13:12.600 We're looking across billions of light years of empty space 274 00:13:12.639 --> 00:13:15.320 to see a wind made of transparent gas. How on 275 00:13:15.399 --> 00:13:17.480 Earth do you observe an invisible wind moving away from 276 00:13:17.519 --> 00:13:19.879 a tiny pinprick of light from the dawn of the universe. 277 00:13:20.200 --> 00:13:23.679 That observational challenge is. It's immense. 278 00:13:23.759 --> 00:13:24.679 It sounds impossible. 279 00:13:25.039 --> 00:13:28.120 Historically, if astronomers wanted to study anything in that level 280 00:13:28.120 --> 00:13:31.080 of detail at high redshift, they had to rely on 281 00:13:31.120 --> 00:13:33.360 a phenomenon called gravitational lensing. 282 00:13:33.639 --> 00:13:37.279 Ah, gravitational lensing. That's one of those concepts that feels 283 00:13:37.320 --> 00:13:41.639 like magic but is just pure, unadulterated general relativity exactly. 284 00:13:42.039 --> 00:13:46.320 General relativity tells us that massive objects warp the actual 285 00:13:46.440 --> 00:13:48.360 fabric of space time around. 286 00:13:48.080 --> 00:13:49.840 Them like a bowling bowl on a trampoline. 287 00:13:49.960 --> 00:13:53.600 Right, So, imagine ys H thirteen sitting out in the 288 00:13:53.600 --> 00:13:57.080 distant universe pumping out its light. Now, imagine there happens 289 00:13:57.120 --> 00:14:00.000 to be another massive galaxy sitting directly in the lane 290 00:14:00.200 --> 00:14:04.399 of sight between Earth and YSH thirteen, the foreground object. Yes, 291 00:14:04.679 --> 00:14:07.279 as the light from YSH thirteen travels toward us, it 292 00:14:07.399 --> 00:14:10.240 encounters the warped space time created by the gravity of 293 00:14:10.279 --> 00:14:13.440 that foreground galaxy. Ok, the light follows the curvature of 294 00:14:13.519 --> 00:14:15.879 space bending around the foreground object. 295 00:14:15.960 --> 00:14:18.879 So the gravity of the foreground galaxy acts exactly like 296 00:14:18.919 --> 00:14:20.279 a giant glass lens. 297 00:14:20.360 --> 00:14:23.759 It does. It focuses the distant light, magnifying the background quasar, 298 00:14:23.879 --> 00:14:28.279 making it appear significantly brighter and larger than its intrinsic luminosity. 299 00:14:28.440 --> 00:14:31.240 So if you're trying to measure something incredibly faint and 300 00:14:31.279 --> 00:14:34.519 difficult to resolve, like a wind of plaza rushing off 301 00:14:34.519 --> 00:14:38.440 an accretion disc, a cosmic magnifying glass sounds like the 302 00:14:38.480 --> 00:14:41.840 perfect tool, you would think, so, right, Why wouldn't astronomers 303 00:14:41.879 --> 00:14:44.279 just use lensed quasars to study UFOs? 304 00:14:44.720 --> 00:14:49.159 Because a gravitational lens is not a perfectly ground, pristine, 305 00:14:49.279 --> 00:14:52.399 optical lens manufactured in a clean room laboratory. 306 00:14:52.480 --> 00:14:52.919 Oh right. 307 00:14:53.480 --> 00:14:57.639 It is a messy, chaotic galaxy. It is composed of 308 00:14:57.919 --> 00:15:01.879 billions of stars, vast clouds of swirling gas, and complex 309 00:15:01.919 --> 00:15:04.000 halos of invisible dark matter. 310 00:15:04.120 --> 00:15:07.480 So the lens itself is full of smudges and structural flaws. 311 00:15:07.600 --> 00:15:09.559 That's a really great way to think of it. When 312 00:15:09.600 --> 00:15:13.279 you bend light through a galaxy's gravity, you inevitably. 313 00:15:12.679 --> 00:15:14.960 Distort the data because it's uneven. 314 00:15:14.879 --> 00:15:18.799 Exactly, the magnification is rarely uniform across the entire image. 315 00:15:19.039 --> 00:15:22.919 The lens can create multiple distorted mirrored images of the 316 00:15:22.960 --> 00:15:25.080 exact same background quasar. 317 00:15:24.799 --> 00:15:26.919 Like a funhouse mirror, exactly like that. 318 00:15:27.159 --> 00:15:31.159 Furthermore, individual stars within the foreground galaxy can cause microlensing events. 319 00:15:31.200 --> 00:15:32.080 What does that do? 320 00:15:32.120 --> 00:15:35.799 Those temporarily spike the brightness of specific regions of the 321 00:15:35.840 --> 00:15:38.679 accretion disk, throwing off all the calculations. 322 00:15:38.759 --> 00:15:39.120 Wow. 323 00:15:39.200 --> 00:15:41.720 So, if your goal is to precisely measure the velocity 324 00:15:41.720 --> 00:15:44.559 of the structure and the mass of a wind launching 325 00:15:44.639 --> 00:15:48.080 off the innermost stable circular orbit of a black hole. 326 00:15:47.919 --> 00:15:50.600 Which requires insane precision, right. 327 00:15:50.759 --> 00:15:54.120 The distortions introduced by the lens can easily trick you. 328 00:15:54.120 --> 00:15:56.720 You might vastly overestimate the power of the wind or 329 00:15:56.759 --> 00:15:58.519 misinterpret its geometry entirely. 330 00:15:59.000 --> 00:16:01.519 So if we can't use a magnifying glass because it 331 00:16:01.559 --> 00:16:04.840 smears the image encrupts the data, how are astronomers actually 332 00:16:04.879 --> 00:16:06.559 getting a clean look at these systems? 333 00:16:07.039 --> 00:16:11.080 That exact problem led a team of researchers, specifically spearheaded 334 00:16:11.080 --> 00:16:14.799 by Georgio Lenzuzi at IF Bologna to launch a highly 335 00:16:14.840 --> 00:16:19.360 ambitious observational campaign called the Wish Metal Program. 336 00:16:19.080 --> 00:16:21.919 The Wish Will Program, and their strategy was basically to 337 00:16:21.960 --> 00:16:22.639 do this the hard. 338 00:16:22.519 --> 00:16:26.559 Way, precisely. It is a multi year heritage program utilizing 339 00:16:26.600 --> 00:16:29.799 the XMM Newton Space Observatory. Okay, their goal was to 340 00:16:29.840 --> 00:16:35.000 target fifteen hyperluminous completely non lensed quasars at cosmic noon. 341 00:16:35.159 --> 00:16:38.840 And HSSH thirteen was the very first target in this campaign. 342 00:16:39.240 --> 00:16:44.480 Yes, they decided to forego the magnification boost entirely. Instead, 343 00:16:44.679 --> 00:16:48.399 they relied purely on the extreme intrinsic brightness of these 344 00:16:48.440 --> 00:16:53.600 specific quasars, combined with long, incredibly patient observations using our 345 00:16:53.639 --> 00:16:55.360 most sensitive X ray detectors. 346 00:16:55.440 --> 00:16:58.480 This requires a massive amount of telescope time, right, hundreds 347 00:16:58.480 --> 00:17:01.840 of hours they point the XMS Newton and eventually they 348 00:17:01.879 --> 00:17:05.400 pull in the nust Star telescope as well at this tiny, 349 00:17:05.880 --> 00:17:09.400 unmagnified pinprick of X ray lighte Right, But if they 350 00:17:09.440 --> 00:17:12.039 aren't using a lens to physically resolve the shape of 351 00:17:12.079 --> 00:17:15.119 the wind, what is the telescope actually recording? Yeah, we 352 00:17:15.160 --> 00:17:17.480 aren't just taking a long exposure photograph. 353 00:17:17.079 --> 00:17:19.200 Right, Now, a photograph wouldn't tell us anything about the 354 00:17:19.279 --> 00:17:22.839 velocity or the composition of the gas. To decode a UFO, 355 00:17:23.119 --> 00:17:25.160 you have to take a spectrum. You have to read 356 00:17:25.200 --> 00:17:26.559 the cosmic fingerprints. 357 00:17:26.920 --> 00:17:28.920 If you are listening to this and wondering how we 358 00:17:29.039 --> 00:17:31.640 know what stars are made of or how fast galaxies 359 00:17:31.640 --> 00:17:34.759 are moving across the universe, spectroscopy is the answer. 360 00:17:34.799 --> 00:17:37.359 It is the absolute heavy lifter of astrophysics. 361 00:17:37.400 --> 00:17:39.839 It really is. Yeah, but let's dive into X ray 362 00:17:39.920 --> 00:17:42.759 spectroscopy specifically, because the mechanics here are wild. 363 00:17:43.000 --> 00:17:46.279 They really are. At its core, a spectrum is a 364 00:17:46.319 --> 00:17:48.240 barcode of light, a bar code. 365 00:17:48.319 --> 00:17:48.480 Right. 366 00:17:48.680 --> 00:17:51.559 If you pass visible white light through a glass prism, 367 00:17:51.759 --> 00:17:54.519 it disperses into a continuous rainbow. 368 00:17:54.480 --> 00:17:56.920 Like pink Floyd's Dark Side of the Moon cover exactly. 369 00:17:57.200 --> 00:18:00.279 X ray spectroscopy does the exact same thing, just at 370 00:18:00.400 --> 00:18:04.680 vastly higher energy levels. Okay, the superheated accretion disk around 371 00:18:04.759 --> 00:18:09.200 WISH thirteen is acting like a cosmic light bulb, pumping 372 00:18:09.240 --> 00:18:12.000 out a smooth, continuous continuum of X. 373 00:18:12.000 --> 00:18:15.559 Ray energies a blazing rainbow of lethal radiation. 374 00:18:15.920 --> 00:18:19.279 But between that brilliantly glowing disk and the XMM Newton 375 00:18:19.359 --> 00:18:20.519 telescope orbiting Earth. 376 00:18:20.640 --> 00:18:23.039 There is the wind, the ultrafaft outflow. 377 00:18:23.200 --> 00:18:26.680 Yes, this wind is composed of plasma. As the X 378 00:18:26.759 --> 00:18:29.759 rays from the disc travel outward, they must pass through 379 00:18:29.799 --> 00:18:30.720 this outflowing wind. 380 00:18:30.839 --> 00:18:32.920 And when they do, the atoms in the wind interact 381 00:18:32.920 --> 00:18:33.319 with the light. 382 00:18:33.480 --> 00:18:38.400 They do specifically they absorb very specific, highly targeted energies 383 00:18:38.400 --> 00:18:39.160 of X rays. 384 00:18:39.279 --> 00:18:41.519 So when the light finally arise at our detectors here 385 00:18:41.519 --> 00:18:44.880 on Earth, the continuum isn't smooth anymore. The barcode is 386 00:18:44.920 --> 00:18:46.119 missing specific lines. 387 00:18:46.359 --> 00:18:50.200 We call these missing lines absorption features or absorption troughs. 388 00:18:50.599 --> 00:18:54.119 The specific energy that is subtracted from the spectrum tells 389 00:18:54.200 --> 00:18:56.559 us exactly what elements the wind is composed of. 390 00:18:56.680 --> 00:18:59.400 Because every element has a unique signature. 391 00:18:58.960 --> 00:19:02.319 It's a fundamental rule quantum mechanics. Every element on the 392 00:19:02.319 --> 00:19:07.319 periodic table absorbs a unique, irrefutable signature of light based 393 00:19:07.319 --> 00:19:08.960 on its electron configuration. 394 00:19:09.240 --> 00:19:11.559 Okay, but if you're listening to this and trying to 395 00:19:11.559 --> 00:19:15.519 picture the environment right next to a supermassive black hole, 396 00:19:16.400 --> 00:19:19.440 you might see a flaw in that logic. Oh yeah, 397 00:19:19.799 --> 00:19:22.680 the accretion disc is generating tens of millions of degrees 398 00:19:22.680 --> 00:19:26.079 of heat. It is blasting out enough X ray radiation 399 00:19:26.160 --> 00:19:29.799 to outshine an entire galaxy. True, wouldn't normal atoms just 400 00:19:29.799 --> 00:19:32.200 be completely vaporized? How does an atom hold on to 401 00:19:32.319 --> 00:19:35.480