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 00:00:26.920 --> 00:00:28.879 I want you to start by picturing something for me. 8 00:00:29.440 --> 00:00:33.960 You step outside on a clear, crisp, moonless night, Oh. 9 00:00:33.960 --> 00:00:35.719 The best kind of night for stargazing. 10 00:00:35.840 --> 00:00:39.119 Exactly. You look up and you see that familiar breath 11 00:00:39.159 --> 00:00:42.840 taking expanse. You know, the sparkling, distinct points of light, 12 00:00:43.200 --> 00:00:46.159 the deep ink black voids between them, maybe. 13 00:00:45.880 --> 00:00:48.359 Even the faint, sort of misty smudge of our own 14 00:00:48.439 --> 00:00:51.520 milky way stretching across the horizon if you're lucky. 15 00:00:51.399 --> 00:00:54.719 Right, Exactly, it's crisp, it's defined. You were looking through 16 00:00:54.719 --> 00:00:57.200 this incredibly transparent window of our universe. 17 00:00:57.280 --> 00:00:59.920 Yeah, and you can see things that are literally million 18 00:01:00.119 --> 00:01:03.000 of light years away, simply because the space between you 19 00:01:03.079 --> 00:01:04.280 and that object is empty. 20 00:01:04.480 --> 00:01:07.239 It's empty. But now I want you to take that image, 21 00:01:07.280 --> 00:01:11.319 that fundamental human experience of stargazing and just completely erase it. 22 00:01:11.400 --> 00:01:13.599 E RaSE the whole sky, the whole thing. Yeah, I 23 00:01:13.640 --> 00:01:16.760 want you to replace that pristine, starry canvas with something 24 00:01:17.359 --> 00:01:21.079 entirely different. Imagine looking up and instead of stars, you 25 00:01:21.120 --> 00:01:24.959 see nothing but a thick, impenetrable, murky gray fog. 26 00:01:25.359 --> 00:01:27.040 Wow, just fog everywhere. 27 00:01:27.159 --> 00:01:29.920 Yeah, no points of light, no definition at all, just 28 00:01:30.000 --> 00:01:34.200 this oppressive cosmic soup blocking your view in every single direction. 29 00:01:34.439 --> 00:01:37.319 That is. I mean, that's a really unsettling image. 30 00:01:37.040 --> 00:01:40.400 It really is. And the crazy thing is, for roughly 31 00:01:40.480 --> 00:01:44.040 the first billion years of its existence, that is exactly 32 00:01:44.079 --> 00:01:47.200 what our universe looked like. It was completely hidden behind 33 00:01:47.200 --> 00:01:47.719 this veil. 34 00:01:47.920 --> 00:01:51.400 It defies every intuition we have about the cosmos, honestly, 35 00:01:51.719 --> 00:01:54.239 because when we think of space, we inherently think of 36 00:01:54.280 --> 00:01:55.319 empty space. 37 00:01:55.120 --> 00:01:57.400 Right, just a big empty vacuum, exactly. 38 00:01:57.879 --> 00:02:00.439 We think of a perfect vacuum that light can just 39 00:02:00.560 --> 00:02:06.000 travel through uninterrupted for billions of years. But that fundamental transparency, 40 00:02:06.079 --> 00:02:07.920 it's actually a feature that had to be. 41 00:02:08.000 --> 00:02:10.599 Earned, earned. What do you mean by earned, Well, it. 42 00:02:10.560 --> 00:02:13.159 Had to be forged. The early universe was not an 43 00:02:13.199 --> 00:02:16.759 empty vacuum at all. It was choked with this primordial 44 00:02:16.840 --> 00:02:19.520 fog that fundamentally trapped energetic light. 45 00:02:19.800 --> 00:02:22.719 So we are going to take you back today, roughly 46 00:02:22.840 --> 00:02:27.400 twelve billion years in time, to witness this pivotal, almost 47 00:02:27.599 --> 00:02:29.719 unbelievable moment in cosmic. 48 00:02:29.360 --> 00:02:30.719 History, really specific moment. 49 00:02:30.840 --> 00:02:34.319 Yeah, we are going back to watch this tiny, hyperactive, 50 00:02:34.479 --> 00:02:38.080 absolute underdog of a galaxy managed to punch a physical 51 00:02:38.120 --> 00:02:40.280 hole right through that universal darkness. 52 00:02:40.280 --> 00:02:41.280 It's quite the story. 53 00:02:41.639 --> 00:02:44.800 Our goal today is to understand how astronomers have managed 54 00:02:44.840 --> 00:02:48.280 to capture the precise mechanics of this ancient event, an 55 00:02:48.280 --> 00:02:50.680 event that literally changed the fabric of the universe. 56 00:02:50.800 --> 00:02:53.280 The sheer scale of the mystery we are talking about 57 00:02:53.319 --> 00:02:56.840 here is just staggering because understanding this moment and this 58 00:02:56.919 --> 00:03:01.800 specific galaxy. It isn't just about cataloging incredibly distant ancient 59 00:03:01.879 --> 00:03:04.159 star system for the sake of making a list. 60 00:03:04.039 --> 00:03:06.120 Right, It's not just stamp collecting exactly. 61 00:03:06.479 --> 00:03:09.960 We are talking about solving a decade's old mystery in astrophysics. 62 00:03:10.280 --> 00:03:13.759 We're talking about answering the fundamental question of how the 63 00:03:13.840 --> 00:03:19.039 universe transitioned from that dark, opaque expanse into the transparent, 64 00:03:19.360 --> 00:03:21.680 light filled cosmos we have today. 65 00:03:21.400 --> 00:03:23.960 The cosmos that allows us to even exist and look 66 00:03:24.000 --> 00:03:25.280 up at the sky exactly. 67 00:03:25.319 --> 00:03:27.759 It's literally the story of how the lights were permanently 68 00:03:27.759 --> 00:03:28.159 turned on. 69 00:03:28.319 --> 00:03:31.120 Okay, so to really grasp the magnitude of this, we 70 00:03:31.199 --> 00:03:34.199 need to completely understand the environment we are dealing with. Here. 71 00:03:34.680 --> 00:03:37.039 We are talking about a specific era. 72 00:03:37.400 --> 00:03:40.599 Astronomers call it the era of reionization. 73 00:03:40.319 --> 00:03:42.919 Right, the era of realization. So let's establish the timeline 74 00:03:42.919 --> 00:03:48.879 for everyone. The Big Bang happens. The universe is unbelievably hot. 75 00:03:48.639 --> 00:03:51.520 And dense, and as it expands, it starts to cool down. 76 00:03:51.680 --> 00:03:55.199 And for roughly the first billion years after that initial spark, 77 00:03:55.879 --> 00:03:59.919 the space between the newly forming stars and galaxies wasn't empty. 78 00:03:59.680 --> 00:04:00.520 Yeah, not at all. 79 00:04:00.759 --> 00:04:04.599 Was completely filled with neutral hydrogen gas, and this gas 80 00:04:04.680 --> 00:04:08.960 acted as a literal physical barrier, like an opaque wall 81 00:04:09.319 --> 00:04:11.400 to energetic ultraviolet light. 82 00:04:11.840 --> 00:04:14.719 And the physics of why this specific gas acts as 83 00:04:14.719 --> 00:04:16.800 a wall is actually really critical. 84 00:04:16.439 --> 00:04:19.240 Here, walk us through that. Why hydrogen, Well. 85 00:04:19.040 --> 00:04:21.720 When the universe was born, it was essentially this giant 86 00:04:21.879 --> 00:04:26.000 expanding furnace. It was a plasma where protons and electrons 87 00:04:26.000 --> 00:04:28.480 were just violently zipping around because it was so hot, 88 00:04:28.680 --> 00:04:31.759 way too energetic to bond together. Yeah, but as the 89 00:04:31.839 --> 00:04:35.800 universe expanded, the temperature naturally dropped, makes sense, and about 90 00:04:35.839 --> 00:04:38.279 three hundred and eighty thousand years after the Big Bang, 91 00:04:38.360 --> 00:04:41.560 it cooled just enough for those protons and electrons to 92 00:04:41.600 --> 00:04:43.480 finally grab onto each other, and that's. 93 00:04:43.360 --> 00:04:45.199 When they form the very first atoms. 94 00:04:45.480 --> 00:04:50.439 Exactly specifically, they formed neutral hydrogen, which is just one 95 00:04:50.480 --> 00:04:54.240 proton and one electron locked together in this little atomic dance. 96 00:04:54.800 --> 00:04:57.199 Now on the surface, that seems like a good thing, right, 97 00:04:57.279 --> 00:05:00.480 like a step toward order. The universe is organized itself 98 00:05:00.519 --> 00:05:01.360 into atoms. 99 00:05:01.959 --> 00:05:04.600 It was a huge step for matter, but for light 100 00:05:04.839 --> 00:05:06.279 it was a disaster, right. 101 00:05:06.199 --> 00:05:09.360 Because in terms of light, this new order created a 102 00:05:09.399 --> 00:05:12.839 massive problem. I always think of this era like a 103 00:05:12.879 --> 00:05:14.920 frosted glass window in a bathroom. 104 00:05:15.079 --> 00:05:16.399 Oh, that's a good way to look at it. 105 00:05:16.480 --> 00:05:18.000 Yeah, you know, you can stand on the outside of 106 00:05:18.000 --> 00:05:20.600 that window, and you know there's a bright light source 107 00:05:20.680 --> 00:05:23.639 on the inside. You know, someone turned a light bulb. 108 00:05:23.439 --> 00:05:26.040 On, but you can't see the ball itself exactly. 109 00:05:26.560 --> 00:05:30.120 The material of that frosted glass scatters every single photon 110 00:05:30.160 --> 00:05:31.920 that hits it. You can't see the shape of the ball, 111 00:05:32.000 --> 00:05:34.160 you can't see the room. Everything is just scattered into 112 00:05:34.199 --> 00:05:36.480 this hazy, indistinguishable glow. 113 00:05:36.720 --> 00:05:40.560 That's exactly it. That neutral hydrogen was the frosted glass 114 00:05:40.600 --> 00:05:44.199 of the universe, and it was specifically tuned to block 115 00:05:44.240 --> 00:05:47.680 the high energy ultraviolet light being produced by the very first. 116 00:05:47.480 --> 00:05:50.399 Stars, tuned to block it. How does that work? 117 00:05:50.600 --> 00:05:53.519 Your frosted glass analogy works perfectly. When you look at 118 00:05:53.519 --> 00:05:57.600 the quantum mechanics of a hydrogen atom, you see neutral 119 00:05:57.680 --> 00:06:03.439 hydrogen atoms are essentially perfect tuned traps for energetic ultraviolet. 120 00:06:02.800 --> 00:06:04.920 Photons, like they're designed to catch them. 121 00:06:05.319 --> 00:06:08.199 Pretty much. In a neutral atom, the electron is sitting 122 00:06:08.240 --> 00:06:12.199 at its lowest energy state. So when an energetic ultraviolet 123 00:06:12.199 --> 00:06:15.399 photon from a newly born star comes along and hits 124 00:06:15.439 --> 00:06:17.000 that neutral hydrogen. 125 00:06:16.639 --> 00:06:18.240 Atom, the atom just absorbs it. 126 00:06:18.360 --> 00:06:22.199 Yep, the atom's electron absorbs that energy and physically jumps 127 00:06:22.199 --> 00:06:25.079 away from the proton into a higher orbit. The light 128 00:06:25.160 --> 00:06:27.399 doesn't pass through at all, it's just consumed. 129 00:06:27.560 --> 00:06:27.920 Wow. 130 00:06:28.040 --> 00:06:30.680 Its energy is used to excite or even break the 131 00:06:30.720 --> 00:06:34.720 atom apart. So any young hot star trying to shine 132 00:06:34.759 --> 00:06:38.040 its brilliant UV light out into the cosmos would just 133 00:06:38.120 --> 00:06:41.680 find its light immediately swallowed by the surrounding hydrogen fog. 134 00:06:41.800 --> 00:06:43.120 Okay, this is where I want to push back a 135 00:06:43.120 --> 00:06:45.160 little bit, because I think if you were listening to this, 136 00:06:45.600 --> 00:06:48.519 a very logical counter argument might be forming in your head. 137 00:06:48.759 --> 00:06:49.800 Oh, let's hear it. 138 00:06:50.040 --> 00:06:52.800 Well, we know the universe was expanding, right, It has 139 00:06:52.839 --> 00:06:54.759 been expanding since the moment of the Big Bang, and 140 00:06:54.800 --> 00:06:57.600 the actual fabric of space is still stretching today. 141 00:06:57.759 --> 00:06:58.519 That's true. 142 00:06:58.639 --> 00:07:01.360 So if this fog is just made of gas and 143 00:07:01.399 --> 00:07:04.720 the literal space it occupies is stretching out and getting bigger, 144 00:07:05.480 --> 00:07:09.199 shouldn't that neutral hydrogen fog have just naturally stretched out, 145 00:07:09.360 --> 00:07:11.480 thinned out, and dissipated on its. 146 00:07:11.319 --> 00:07:14.279 Own over time, like a cloud of smoke blowing away. 147 00:07:14.439 --> 00:07:18.160 Exactly why campfire smoke dispersing in the wind? Why do 148 00:07:18.240 --> 00:07:22.160 astronomers believe something had to actively violently clear it. 149 00:07:22.680 --> 00:07:24.959 That is a really great question. In connecting it to 150 00:07:25.040 --> 00:07:29.040 cosmic expansion makes complete sense, but it actually highlights the 151 00:07:29.120 --> 00:07:32.639 slight misunderstanding of what expansion does to matter at this 152 00:07:32.800 --> 00:07:33.680 specific scale. 153 00:07:33.720 --> 00:07:35.240 Okay, correct me, what am I missing? 154 00:07:35.480 --> 00:07:38.680 Yes, the universe was expanding, which means the average distance 155 00:07:38.720 --> 00:07:42.040 between galaxies was increasing, So the overall density of the 156 00:07:42.079 --> 00:07:44.759 gas in the universe was very slowly decreasing. 157 00:07:44.839 --> 00:07:45.959 Right, It's spreading out. 158 00:07:46.079 --> 00:07:49.680 But and this is the key, physical expansion alone does 159 00:07:49.680 --> 00:07:53.240 not change the chemical or electrical state of the gas itself. 160 00:07:53.480 --> 00:07:56.639 Oh I see, So just spreading the atoms further apart 161 00:07:56.720 --> 00:07:59.839 doesn't stop them from being a trap for the light exactly. 162 00:08:00.079 --> 00:08:03.199 Let's follow that logic. Even if the hydrogen atoms are 163 00:08:03.240 --> 00:08:06.040 slightly further apart from one another due to the stretching 164 00:08:06.079 --> 00:08:10.000 of space, they are still fundamentally neutral hydrogen. 165 00:08:10.160 --> 00:08:12.920 They still have that electron waiting to catch a photon bingo. 166 00:08:13.720 --> 00:08:17.399 They still possess that perfectly positioned electron. So if a 167 00:08:17.399 --> 00:08:21.560 photon travels through space, eventually it will hit one of 168 00:08:21.600 --> 00:08:23.519 these atoms, no matter how spread out they. 169 00:08:23.399 --> 00:08:25.600 Are, because there's just so much space to cross. 170 00:08:25.759 --> 00:08:28.560 Right, to make the universe truly transparent, to give us 171 00:08:28.600 --> 00:08:31.519 the clear night sky, you couldn't just thin the fog out. 172 00:08:31.879 --> 00:08:35.000 You had to fundamentally alter the nature of the fog itself. 173 00:08:35.039 --> 00:08:36.080 You had to change the gas. 174 00:08:36.279 --> 00:08:38.919 Yes, you had to change it from a neutral state 175 00:08:39.320 --> 00:08:41.799 back into an ionized. 176 00:08:41.200 --> 00:08:44.879 Plasma, Which means we need to define ionization for everyone, 177 00:08:44.960 --> 00:08:47.519 because to ionize a gas, you essentially have to break 178 00:08:47.519 --> 00:08:47.919 the atom. 179 00:08:48.000 --> 00:08:51.519 Right, It is a totally destructive process. Yeah, ionization is 180 00:08:51.559 --> 00:08:55.879 the act of literally ripping the electron away from the proton. 181 00:08:55.600 --> 00:08:58.039 Entirely, so you're not just exciting the electron, you're kicking 182 00:08:58.080 --> 00:08:59.360 it out exactly. 183 00:08:59.799 --> 00:09:03.000 Have to hit that neutral hydrogen atom with an overwhelming 184 00:09:03.039 --> 00:09:06.879 amount of energetic ultraviolet light, so much energy that the 185 00:09:06.919 --> 00:09:09.840 electron is violently and permanently stripped away. 186 00:09:09.960 --> 00:09:10.919 And once that happens. 187 00:09:10.960 --> 00:09:14.960 When that happens, the gas becomes ionized, and ionized hydrogen, 188 00:09:15.080 --> 00:09:18.440 missing its electron, no longer has the mechanism to absorb 189 00:09:18.480 --> 00:09:20.519 that same ultraviolet. 190 00:09:19.960 --> 00:09:21.399 Light because the trap is gone. 191 00:09:21.440 --> 00:09:24.559 The trap is gone, the photon can finally pass right 192 00:09:24.639 --> 00:09:27.600 through the empty space of the atom unimpeded. To use 193 00:09:27.639 --> 00:09:30.960 your analogy, the frosted glass suddenly becomes a pane of 194 00:09:31.080 --> 00:09:32.399 clear glass. 195 00:09:32.039 --> 00:09:34.720 That is wild. So to clear the cosmic fog, the 196 00:09:34.840 --> 00:09:38.360 universe literally had to be blasted with radiation on an 197 00:09:38.440 --> 00:09:39.600 unimaginable scale. 198 00:09:39.679 --> 00:09:42.919 It really did. And this change over this era of realization, 199 00:09:43.320 --> 00:09:44.279 it was not a quick. 200 00:09:44.120 --> 00:09:46.360 Transition, wasn't just slipping a switch, not at all. 201 00:09:46.480 --> 00:09:50.080 It was an incredibly grueling, violent process. It was a 202 00:09:50.080 --> 00:09:53.000 cosmic war of attrition that took hundreds of millions of 203 00:09:53.039 --> 00:09:53.759 years to complete. 204 00:09:53.840 --> 00:09:56.600 Hundreds of millions of years of just bombarding. 205 00:09:56.080 --> 00:09:59.320 Gas photon by photon. The earliest stars were fighting back 206 00:09:59.360 --> 00:10:02.559 against the fog doug stripping electrons away and gradually carving 207 00:10:02.559 --> 00:10:04.639 out these tiny bubbles of transparent space. 208 00:10:04.919 --> 00:10:06.799 And I guess those bubbles eventually grew. 209 00:10:07.039 --> 00:10:11.039 Yeah, over hundreds of millions of years, those clear bubbles expanded, 210 00:10:11.200 --> 00:10:16.120 they overlapped, and finally merged together to clear the entire cosmos. 211 00:10:16.600 --> 00:10:19.600 It is just staggering to think about. I mean, the deep, 212 00:10:19.720 --> 00:10:23.080 transparent vacuum of space we see today is actually the 213 00:10:23.120 --> 00:10:27.200 aftermath of a billion year long radiation bombardment. 214 00:10:27.279 --> 00:10:29.600 It's the debris field of a very long war. 215 00:10:29.879 --> 00:10:33.759 But if the cosmic fog didn't just passively dissipate, if 216 00:10:33.799 --> 00:10:36.559 it had to be violently burned away from the inside out, 217 00:10:36.840 --> 00:10:39.440 that means something incredibly powerful had to be doing. 218 00:10:39.279 --> 00:10:41.679 The burning, something very bright and very energetic. 219 00:10:41.799 --> 00:10:45.879 Right. But for a long time, the exact mechanism, the 220 00:10:45.960 --> 00:10:48.879 specific culprits that managed to pull this off, they were 221 00:10:48.919 --> 00:10:50.919 completely shrouded in that very same fog. 222 00:10:51.080 --> 00:10:53.360 It's a cruel irony. The fog hid the things that 223 00:10:53.399 --> 00:10:55.159 were clearing the fog exactly. 224 00:10:55.320 --> 00:10:57.559 Astronomers couldn't see them doing it. We knew the fog 225 00:10:57.600 --> 00:11:00.159 cleared eventually, but we didn't have the smoking gun, which 226 00:11:00.200 --> 00:11:03.360 brings us to this recently discovered, highly unlikely little galaxy 227 00:11:03.399 --> 00:11:04.840 that has completely changed the game. 228 00:11:05.039 --> 00:11:08.200 This is where the narrative really shifts. Yeah, we move 229 00:11:08.279 --> 00:11:12.399 from the theoretical mechanics of the early universe to a specific, 230 00:11:12.879 --> 00:11:15.399 astonishing hard data observation. 231 00:11:15.559 --> 00:11:19.039 So let's meet the cosmic underdog. It has a very catchy, 232 00:11:19.080 --> 00:11:23.120 memorable catalog name MXDF four point four. 233 00:11:23.159 --> 00:11:24.600 Rolls right off the tongue, doesn't it. 234 00:11:24.639 --> 00:11:26.559 Oh yeah, I'm sure someone will write a song about it. 235 00:11:26.759 --> 00:11:30.559 But this little galaxy existed roughly one point four billion 236 00:11:30.679 --> 00:11:31.919 years after the Big. 237 00:11:31.720 --> 00:11:33.840 Bang, and that timing is crucial. 238 00:11:33.799 --> 00:11:36.159 Right, because that places it right at the very tail 239 00:11:36.279 --> 00:11:40.399 end of this transformative era of realization. It's essentially sitting 240 00:11:40.519 --> 00:11:43.039 right at the finish line of this cosmic transition. 241 00:11:43.440 --> 00:11:46.000 Its placement in time is exactly what makes it so 242 00:11:46.080 --> 00:11:49.399 incredibly significant, because at one point four billion years the 243 00:11:49.519 --> 00:11:51.399 universe was still very much a mixed bag. 244 00:11:51.600 --> 00:11:52.759 What do you mean by a mixed bag? 245 00:11:52.799 --> 00:11:55.519 Well, the realization process was finishing up, sure, but there 246 00:11:55.519 --> 00:11:59.679 were still massive intercalective clouds of opaque gas everywhere, a 247 00:12:00.000 --> 00:12:01.360 deeply transitional. 248 00:12:00.840 --> 00:12:03.080 Period, so totally clear yet right. 249 00:12:03.000 --> 00:12:05.639 Which makes it the perfect laboratory to see this clearing 250 00:12:05.679 --> 00:12:08.440 process actively happening, assuming you could find a way to 251 00:12:08.480 --> 00:12:11.120 peer through the remaining haze to actually see the source. 252 00:12:10.840 --> 00:12:13.440 Which we'll get to. But when I first started looking 253 00:12:13.480 --> 00:12:17.120 at the profile of this galaxy MXTSC four point four, 254 00:12:17.679 --> 00:12:20.840 I really struggle to wrap my head around its physical scale. 255 00:12:20.919 --> 00:12:23.879 It's unintuitive, for sure, Yeah, because when we talk about 256 00:12:23.960 --> 00:12:27.080 galaxies that have the power to change the universe, we 257 00:12:27.200 --> 00:12:31.840 tend to picture these massive, sprawling, majestic spirals like our 258 00:12:31.879 --> 00:12:32.840 own Milky. 259 00:12:32.519 --> 00:12:35.000 Way giant pin wheels of stars exactly. 260 00:12:35.399 --> 00:12:38.879 But to really grasp what this ancient galaxy is doing, 261 00:12:38.919 --> 00:12:41.720 you have to realize how bizarre its proportions are. I 262 00:12:41.759 --> 00:12:43.600 actually like to compare it to a coffee machine. 263 00:12:43.679 --> 00:12:45.960 Okay, you're gonna have to elaborate on that. How does 264 00:12:45.960 --> 00:12:49.639 a twelve billion year old galaxy resemble a coffee machine? 265 00:12:49.759 --> 00:12:52.720 Bear with me. Think of our Milky Way galaxy as 266 00:12:52.759 --> 00:12:57.440 a massive, slow drip commercial coffee maker and giant diner. Okay, 267 00:12:57.519 --> 00:12:59.840 it is huge, It takes up a lot of space. 268 00:13:00.279 --> 00:13:03.840 It steadily reliably produces coffee all day long at a 269 00:13:03.919 --> 00:13:08.240 very measured, manageable pace. That's our galaxy right now for me, 270 00:13:08.399 --> 00:13:10.240 just a few new stars every single year. 271 00:13:10.440 --> 00:13:12.159 It's calm, it's spread out, right. 272 00:13:12.480 --> 00:13:15.000 But MXDFC four point four is like taking the motor 273 00:13:15.039 --> 00:13:18.399 of a high powered industrial espresso machine, putting it in 274 00:13:18.399 --> 00:13:21.559 a tiny, cramped, sealed cardboard box and running it on 275 00:13:21.759 --> 00:13:25.399 absolute maximum overdrive until it starts shaking itself apart. 276 00:13:25.600 --> 00:13:28.440 That is a very chaotic mental image, but it fits 277 00:13:28.759 --> 00:13:32.679 because this newly discovered galaxy is one hundred times smaller 278 00:13:32.960 --> 00:13:37.360 by area than our milky Way, one hundred times smaller. 279 00:13:37.000 --> 00:13:39.360 A tiny fraction of the size, and yet. 280 00:13:39.200 --> 00:13:42.799 In that microscopic, cramped space, it is churning out new 281 00:13:42.879 --> 00:13:45.159 stars ten times faster than we are. 282 00:13:45.320 --> 00:13:48.279 And taking your analogy further, it's not just an industrial 283 00:13:48.399 --> 00:13:51.600 espresso machine in a cardboard box. The box is filled 284 00:13:51.600 --> 00:13:54.480 with the raw material. It's full of the dense gas 285 00:13:54.480 --> 00:13:56.240 and dust required to make those stars. 286 00:13:56.320 --> 00:13:57.320 Right, it's completely stuff. 287 00:13:57.440 --> 00:13:59.960 The visual of that is incredibly chaotic, and it perfectly 288 00:14:00.120 --> 00:14:02.720 aligns with the physics. What you are describing is a 289 00:14:02.720 --> 00:14:06.399 phenomenon that the lead researcher on this discovery ilias Gubertz 290 00:14:06.720 --> 00:14:08.919 refers to as the crowding effect. 291 00:14:08.960 --> 00:14:09.879 The crowding effect. 292 00:14:10.039 --> 00:14:15.440 Yes, this is the fundamental secret weapon of MXDFC four 293 00:14:15.480 --> 00:14:19.279 point four. It isn't just that it's producing stars rapidly. 294 00:14:19.679 --> 00:14:22.840 It is the specific aggressive nature of those stars and 295 00:14:22.879 --> 00:14:25.720 the extreme proximity in which they are forced to exist. 296 00:14:25.840 --> 00:14:27.440 They are completely crammed together. 297 00:14:27.559 --> 00:14:30.639 Crammed is almost an understatement. The galaxy is forcing the 298 00:14:30.679 --> 00:14:34.919 creation of massive, young, incredibly hot stars into a minuscule 299 00:14:35.000 --> 00:14:36.360 cosmic footprint. 300 00:14:35.919 --> 00:14:38.159 So they're basically sitting on top of each other exactly. 301 00:14:38.240 --> 00:14:41.159 And furthermore, these stars aren't forming in a steady, even 302 00:14:41.279 --> 00:14:45.399 drip like your diner coffee maker. They form in violent, sudden. 303 00:14:45.080 --> 00:14:46.320 Bursts, like all at once. 304 00:14:46.399 --> 00:14:49.120 The data shows that a massive percentage of these highly 305 00:14:49.240 --> 00:14:52.879 energetic stars formed within just the last few million years 306 00:14:52.919 --> 00:14:55.519 of the galaxy's existence. At that point in time, it's 307 00:14:55.519 --> 00:14:57.759 not a slow burn at all. It is an absolute 308 00:14:57.840 --> 00:14:59.600 explosion of stellar birth. 309 00:14:59.720 --> 00:15:04.559 Wow. So you have this microscopic galaxy by cosmic standards, 310 00:15:04.639 --> 00:15:08.000 just packed shoulder to shoulder with the hottest, most aggressive 311 00:15:08.000 --> 00:15:11.000 type of stars possible, all igniting at it essentially the 312 00:15:11.039 --> 00:15:12.080 exact same time and. 313 00:15:12.039 --> 00:15:14.639 Because they are so young and incredibly massive, they are 314 00:15:14.679 --> 00:15:17.360 burning at surface temperatures that make our sun look like 315 00:15:17.399 --> 00:15:18.480 a dying ember. 316 00:15:18.480 --> 00:15:20.200 Just unimaginably hot. 317 00:15:20.320 --> 00:15:25.159 They are producing an overwhelming, blinding flood of that specific 318 00:15:25.279 --> 00:15:28.440 high energy ionizing ultraviolet light we talked. 319 00:15:28.200 --> 00:15:30.320 About earlier, the light that clears the fog. 320 00:15:31.039 --> 00:15:34.600 Yes, they are manufacturing the exact type of light needed 321 00:15:34.639 --> 00:15:37.399 to strip the electrons from the neutral hydrogen and clear 322 00:15:37.440 --> 00:15:38.000 the universe. 323 00:15:38.080 --> 00:15:40.639 Okay, but this is where my brand hits a massive roadblock. 324 00:15:41.080 --> 00:15:43.879 And honestly, if you're listening to this and following the 325 00:15:43.919 --> 00:15:45.960 logic here, I think you might be stuck in the 326 00:15:45.960 --> 00:15:46.759 exact same place. 327 00:15:46.960 --> 00:15:47.960 Let's hear the roadblock. 328 00:15:48.200 --> 00:15:52.679 We have this cluster of ridiculously bright hot stars in 329 00:15:52.759 --> 00:15:55.960 a very confined space that is a great power source. 330 00:15:56.559 --> 00:15:59.559 But simply having a power source isn't enough to permanently 331 00:15:59.600 --> 00:16:02.840 alter the fabric of the surrounding universe. True, how exactly 332 00:16:02.840 --> 00:16:05.480 does their light manage to break out of the galaxy itself? 333 00:16:05.759 --> 00:16:08.840 Because think about it. A galaxy that is forming stars 334 00:16:08.840 --> 00:16:12.879 that rapidly is by definition full of the raw material 335 00:16:12.960 --> 00:16:13.919 needed to make stars. 336 00:16:14.039 --> 00:16:16.519 It has to be. You can't make stars without gas. 337 00:16:16.200 --> 00:16:19.879 Right, It is full of dense gas and thick cosmic dust. 338 00:16:19.919 --> 00:16:20.879 It is choked with it. 339 00:16:21.120 --> 00:16:23.919 That is the pivotal question. And you've just articulated the 340 00:16:23.960 --> 00:16:28.399 exact paradox that has stumped astrophysicists for years when looking 341 00:16:28.440 --> 00:16:29.600 at these early galaxies. 342 00:16:29.799 --> 00:16:31.799 Because if I am standing in the middle of a thick, 343 00:16:31.919 --> 00:16:35.440 choking cloud of campfire smoke and I turn on a 344 00:16:35.480 --> 00:16:38.879 tremendously powerful military grade flashlight. 345 00:16:38.399 --> 00:16:39.679 It doesn't matter how strong the. 346 00:16:39.720 --> 00:16:42.639 Light is, exactly most of that light just hits the 347 00:16:42.639 --> 00:16:45.440 smoke immediately in front of me and scatters. It creates 348 00:16:45.440 --> 00:16:48.799 a bright, blinding wall of white right in my face. 349 00:16:48.919 --> 00:16:50.120 You basically blind yourself. 350 00:16:50.240 --> 00:16:53.200 Yeah, it physically cannot clear the air across the campsite. 351 00:16:53.480 --> 00:16:56.559 The smoke absorbs and deflexs it. So how on Earth 352 00:16:56.600 --> 00:17:00.720 does literally almost all of this ionizing light from MXDFIVEVACA 353 00:17:01.039 --> 00:17:04.599 four point four escape the galaxy without just getting instantly 354 00:17:04.599 --> 00:17:07.119 absorbed by the galaxy's own internal gas and dust. 355 00:17:07.240 --> 00:17:08.920 The light shouldn't be able to leave the building. 356 00:17:08.920 --> 00:17:11.720 It's essentially right, it should be trapped inside well. 357 00:17:12.000 --> 00:17:15.079 Resolving that paradox brings us to what might be the 358 00:17:15.079 --> 00:17:19.079 most dramatic and awe inspiring mechanism in all of astrophysics. 359 00:17:19.440 --> 00:17:21.160 This is the mechanics of the Great escape. 360 00:17:21.200 --> 00:17:21.960 The great escape. 361 00:17:22.039 --> 00:17:25.680 I love that your intuition is entirely correct. The light 362 00:17:25.759 --> 00:17:27.960 on its own, no matter how bright, would just be 363 00:17:28.000 --> 00:17:31.359 swallowed by the immediate dusty environment of the galaxy, So. 364 00:17:31.319 --> 00:17:33.440 The flesh light doesn't work on its own exactly. 365 00:17:33.519 --> 00:17:35.359 To get the light out, you have to physically clear 366 00:17:35.400 --> 00:17:37.440 a path. You have to move the smoke out of 367 00:17:37.480 --> 00:17:37.759 the way. 368 00:17:38.440 --> 00:17:40.359 And how does a galaxy move. 369 00:17:40.200 --> 00:17:44.240 The smoke the way MXDFZ four point four moves the 370 00:17:44.279 --> 00:17:46.480 smoke is through utter catastrophe. 371 00:17:46.920 --> 00:17:50.039 Okay, let's talk about the catastrophe. Yeah, what is physically 372 00:17:50.079 --> 00:17:52.720 happening to the gas inside that little box? 373 00:17:52.960 --> 00:17:55.119 We have to look closely at the life cycles of 374 00:17:55.160 --> 00:17:58.759 these specific types of massive stars in the universe. There 375 00:17:58.839 --> 00:18:03.200 is a brutal, unbreakable rule. The brightest, most massive stars 376 00:18:03.319 --> 00:18:04.000 burn out the. 377 00:18:03.920 --> 00:18:06.480 Fastest because they're using up their fuel so quickly. 378 00:18:06.680 --> 00:18:10.160 Exactly, a relatively calm star like our sun will live 379 00:18:10.200 --> 00:18:14.440 for about ten billion years, slowly and steadily fusing hydrogen 380 00:18:14.519 --> 00:18:16.319 in its core. It's very stable. 381 00:18:16.480 --> 00:18:18.640 Slow and steady wins the race, right. 382 00:18:18.960 --> 00:18:22.400 But the massive super hot stars being churned out in 383 00:18:22.480 --> 00:18:26.599 these violent bursts within mxdf z four point four. They 384 00:18:26.640 --> 00:18:30.079 are so massive and their internal gravity is crushing their 385 00:18:30.119 --> 00:18:33.880 cores so intensely that they burn through their nuclear fuel 386 00:18:34.000 --> 00:18:36.079 at an astonishing reckless rate. 387 00:18:36.240 --> 00:18:37.200 How fast are we talking? 388 00:18:37.440 --> 00:18:40.839 They live for only a few million years in cosmic terms, 389 00:18:40.880 --> 00:18:42.000 That is the blink of an eye. 390 00:18:42.039 --> 00:18:43.960 They are the rock stars of the universe. They live 391 00:18:44.079 --> 00:18:46.279 fast and they die extremely young. 392 00:18:46.400 --> 00:18:48.640 That's a perfect way to put it. And their deaths 393 00:18:48.799 --> 00:18:50.680 are the key to the entire mystery. 394 00:18:50.839 --> 00:18:52.039 What happens when they die? 395 00:18:52.200 --> 00:18:55.519 Well, when a star that massive inevitably runs out of fuel, 396 00:18:55.640 --> 00:18:59.720 the outward pressure generated by nuclear fusion suddenly stalks, and 397 00:18:59.759 --> 00:19:02.480 with out that outward pressure, the immense gravity of the 398 00:19:02.480 --> 00:19:05.200 star causes the entire core to collapse in on itself 399 00:19:05.240 --> 00:19:06.359 in a fraction of a second. 400 00:19:06.440 --> 00:19:08.440 Oh wow, just instant collapse. 401 00:19:08.559 --> 00:19:12.400