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 Astronomy podcast. Each episode offers a 3 00:00:12.359 --> 00:00:16.320 gentle journey through the stars, planets, and beyond, perfect for 4 00:00:16.399 --> 00:00:20.239 unwinding after a long day. Let's travel through the mysteries 5 00:00:20.239 --> 00:00:22.440 of the universe as you drift off into a peaceful 6 00:00:22.480 --> 00:00:23.800 slumber under the night sky. 7 00:00:27.000 --> 00:00:30.559 Have you ever just stopped and really considered what shaped 8 00:00:30.559 --> 00:00:31.239 the universes? 9 00:00:31.480 --> 00:00:31.760 Yeah? 10 00:00:31.839 --> 00:00:33.799 Not its size, right, No, not the size, but it's 11 00:00:34.000 --> 00:00:39.159 actual fundamental geometry for what the last century, the answer 12 00:00:39.479 --> 00:00:42.840 that has really been the bedrock of modern cosmology has 13 00:00:42.880 --> 00:00:48.399 been astonishingly simple. That it's perfect, perfectly uniform, consistent, and 14 00:00:48.880 --> 00:00:51.240 this is the most important part, symmetrical. 15 00:00:51.759 --> 00:00:55.000 And you know that assumption of universal symmetry. It's more 16 00:00:55.039 --> 00:00:58.679 than just some elegant philosophical idea. Oh absolutely, it's what 17 00:00:58.799 --> 00:01:03.640 allows physics to work on the grandest cosmic scales. I mean, 18 00:01:03.719 --> 00:01:06.959 without it, the mathematical description of the universe, which is 19 00:01:07.000 --> 00:01:11.799 all rooted in Einstein's general relativity, it just becomes impossible, unmanageable. 20 00:01:12.079 --> 00:01:14.560 It simplifies the equations to a point where we can 21 00:01:14.560 --> 00:01:18.640 actually build a working predictive model of the entire cosmos. 22 00:01:18.680 --> 00:01:20.599 And that's the model we all learn about, right, the 23 00:01:20.640 --> 00:01:24.840 one everyone references from undergraduate physics to the latest research papers, 24 00:01:25.200 --> 00:01:28.799 the Standard Cosmological Model LAMB to CDM. It's beautiful in 25 00:01:28.840 --> 00:01:32.879 its success. It explains everything from the slight temperature ripples 26 00:01:32.879 --> 00:01:35.680 in the early universe all the way to the mechanism's 27 00:01:35.760 --> 00:01:37.040 driving cosmic expansion. 28 00:01:37.159 --> 00:01:37.719 He really does. 29 00:01:38.239 --> 00:01:43.000 But what happens if we find out that this foundational assumption, 30 00:01:43.079 --> 00:01:46.959 this idea of perfect symmetry is actually wrong. What if 31 00:01:47.000 --> 00:01:49.680 the universe is well inherently lopsided. 32 00:01:49.959 --> 00:01:52.719 That is precisely the core tension we are looking at today. 33 00:01:53.079 --> 00:01:57.040 This discussion focuses on a major review, one that synthesizes 34 00:01:57.159 --> 00:02:01.560 years and years of observational data that this elegant uniform 35 00:02:01.640 --> 00:02:04.959 cosmos might actually be fundamentally asymmetric. 36 00:02:05.000 --> 00:02:06.439 And it's not just a small problem. 37 00:02:06.599 --> 00:02:09.800 No, it's a challenge to the standard model so profound 38 00:02:10.000 --> 00:02:13.360 that some researchers are suggesting it forces us to reconsider 39 00:02:13.400 --> 00:02:16.039 the most basic mathematical premises of space and time. 40 00:02:16.159 --> 00:02:18.479 We're looking into what is I think maybe the most 41 00:02:18.479 --> 00:02:22.400 significant structural challenge to the standard model yet the cosmic 42 00:02:22.439 --> 00:02:26.360 Diepool anomaly. This is a scientific discord so measurable, so 43 00:02:26.520 --> 00:02:29.960 robust across all these different observational techniques that it may 44 00:02:30.039 --> 00:02:33.840 force physicists to what potentially scrap the current framework entirely 45 00:02:34.159 --> 00:02:35.560 and truly go back to square one. 46 00:02:35.840 --> 00:02:38.520 That's the question on the table. So our mission today 47 00:02:38.560 --> 00:02:42.080 is to really understand the fundamental assumptions that birth this 48 00:02:42.240 --> 00:02:46.680 symmetric universe model. Why one of the most precise consistency 49 00:02:46.719 --> 00:02:51.120 tests in cosmology has failed so spectacularly in recent years, 50 00:02:51.479 --> 00:02:54.759 and you know what a lopsided universe truly implies for 51 00:02:54.800 --> 00:02:55.800 the future of physics. 52 00:02:56.000 --> 00:02:58.919 Okay, let's unpack this, starting with that very first idea, 53 00:02:59.080 --> 00:03:01.360 the idea of a perfectly symmetric universe. 54 00:03:01.800 --> 00:03:04.400 So when we talk about the bedrock of modern cosmology, 55 00:03:04.719 --> 00:03:08.319 we are really talking about two fundamental linked principles that 56 00:03:08.360 --> 00:03:12.159 govern the cosmos on the largest scales, uniformity and isotropy, 57 00:03:12.319 --> 00:03:14.879 and together they form the cosmological principle. 58 00:03:14.960 --> 00:03:16.960 Okay, let's nail down those two terms, because I think 59 00:03:16.960 --> 00:03:20.080 they're often used interchangeably, but they mean very distinct things 60 00:03:20.080 --> 00:03:21.719 in this context, right they do. 61 00:03:21.800 --> 00:03:26.000 So Uniformity or what we call homogeneity, means that if 62 00:03:26.039 --> 00:03:28.759 you zoom out far enough, and we're talking scales exceeding 63 00:03:28.800 --> 00:03:32.680 say one point two billion light years. The universe looks 64 00:03:32.680 --> 00:03:33.240 the same. 65 00:03:33.080 --> 00:03:35.280 Everywhere, so location doesn't matter, right. 66 00:03:35.319 --> 00:03:37.840 Think of it this way. If you take a cubic 67 00:03:37.919 --> 00:03:41.039 mile of water in the middle of the ocean, it 68 00:03:41.080 --> 00:03:44.159 looks exactly the same as any other cubic mile of water. 69 00:03:44.280 --> 00:03:46.520 You couldn't tell where you were just based on the 70 00:03:46.560 --> 00:03:47.680 water itself. 71 00:03:47.280 --> 00:03:50.400 Exactly, the average density, the chemical composition, it's all the same. 72 00:03:50.680 --> 00:03:54.000 So similarly, in the universe, if you pick a random 73 00:03:54.199 --> 00:03:58.240 billion light year cube of space in one location, it 74 00:03:58.280 --> 00:04:01.080 will have the same average density of matter and the 75 00:04:01.080 --> 00:04:04.680 same average distribution of galaxies as a cube taken from 76 00:04:04.680 --> 00:04:07.159 the complete opposite side of the observable universe. 77 00:04:07.199 --> 00:04:09.919 But hang on a second. We know the universe is clumpy. 78 00:04:10.000 --> 00:04:13.240 I mean, we see galaxies, we see clusters of galaxies, 79 00:04:13.280 --> 00:04:16.439 we see these huge voids. Isn't that already a violation 80 00:04:16.519 --> 00:04:17.399 of homogeneity. 81 00:04:17.519 --> 00:04:19.759 That is a critical point, and it's why we always 82 00:04:19.759 --> 00:04:24.160 have to add that caveat on large scales. Okay, Yes, Locally, 83 00:04:24.199 --> 00:04:26.439 the universe is extremely in homogeneous. I mean, if you 84 00:04:26.560 --> 00:04:29.600 compared a cubic meter containing Earth to a cubic meter 85 00:04:29.680 --> 00:04:34.439 of vacuum in deep space, they are vastly different. But 86 00:04:34.519 --> 00:04:38.560 the cosmological principle argues that these local differences they just 87 00:04:38.639 --> 00:04:42.319 smooth out completely once you average over truly immense volumes. 88 00:04:42.600 --> 00:04:45.600 The structures what we call the cosmic web, they're just 89 00:04:45.720 --> 00:04:48.120 you know, ripples on it, otherwise uniform fluid. 90 00:04:48.800 --> 00:04:51.879 So homogeneity is about location independence, it doesn't matter where 91 00:04:51.959 --> 00:04:57.160 you are. And the second principle isotropy. That's about direction independence. 92 00:04:57.480 --> 00:05:00.279 Correct isotropy means the universe looks the same in all 93 00:05:00.319 --> 00:05:03.000 directions from our vantage point. If you were floating in 94 00:05:03.079 --> 00:05:06.000 deep space and looked left, right, up or down. The 95 00:05:06.120 --> 00:05:09.720 overall statistical picture of the cosmos, the distribution of distant 96 00:05:09.800 --> 00:05:13.040 light sources, the density of gas, it would all appear identical. 97 00:05:13.360 --> 00:05:16.879 And the standard cosmological model LAMB to CDM it rests 98 00:05:16.920 --> 00:05:19.360 squarely on both of these ideas being true. 99 00:05:19.279 --> 00:05:23.079 Exactly on the conjunction of both isotropy and homogeneity. Once 100 00:05:23.120 --> 00:05:25.920 you average things out on these massive scales. That's the 101 00:05:25.920 --> 00:05:27.519 cosmological principle. 102 00:05:27.199 --> 00:05:30.480 And this symmetric vision. It wasn't just like a pretty 103 00:05:30.480 --> 00:05:34.560 philosophical choice. Historically, it was a practical necessity it was 104 00:05:34.639 --> 00:05:38.199 shortcut for handling the monster that is general relativity. 105 00:05:38.519 --> 00:05:42.399 Absolutely, the equations of general relativity describe how matter and 106 00:05:42.639 --> 00:05:46.199 energy curve space time, and then how that curve space 107 00:05:46.319 --> 00:05:50.480 time dictates where matter and energy move. They are incredibly 108 00:05:50.519 --> 00:05:52.759 complex tensor equations. 109 00:05:52.160 --> 00:05:54.839 So you couldn't possibly account for every single star. 110 00:05:55.040 --> 00:05:57.600 Not even close. If you had to account for every star, 111 00:05:57.879 --> 00:06:02.399 every galaxy in their unique gravityational interaction across the entire cosmos, 112 00:06:03.720 --> 00:06:06.800 the equations would be impossible to solve analytically. You'd have 113 00:06:07.000 --> 00:06:10.519 effectively infinite complexity that change is based on every tiny 114 00:06:10.519 --> 00:06:11.279 clump of matter. 115 00:06:11.439 --> 00:06:14.560 So by enforcing this assumption that the universe is homogeneous 116 00:06:14.560 --> 00:06:18.480 and isotropic on large scales, cosmologists can basically treat the 117 00:06:18.519 --> 00:06:21.800 whole universe as a smooth, perfectly fluid simple thing. 118 00:06:21.959 --> 00:06:25.240 That's the trick. That assumption allows them to apply a specific, 119 00:06:25.360 --> 00:06:29.120 highly constrained mathematical description space time, one that provides the 120 00:06:29.160 --> 00:06:34.319 maximum possible symmetry. This specific structure is called the FLRW description. 121 00:06:34.160 --> 00:06:36.000 Named after the scientists who developed. 122 00:06:35.720 --> 00:06:39.240 It right Friedman, La Madra, Robertson, and Walker. They developed 123 00:06:39.240 --> 00:06:41.439 it throughout the early twentieth century. 124 00:06:41.279 --> 00:06:45.240 And the FLRW description is really the core mathematical engine 125 00:06:45.279 --> 00:06:48.639 of the model. It takes that unmanageable complexity of general 126 00:06:48.680 --> 00:06:52.319 relativity and turns it into a set of differential equations 127 00:06:52.360 --> 00:06:53.759 that you can actually solve. 128 00:06:53.560 --> 00:06:55.839 And that you can use to capture things like the 129 00:06:55.920 --> 00:06:57.040 expansion rate of space. 130 00:06:57.360 --> 00:07:00.480 It's the whole basis for the LAMB to CDM, the 131 00:07:00.639 --> 00:07:01.199 entire thing. 132 00:07:01.680 --> 00:07:05.279 It successfully captures the observed expansion, the geometry of space, 133 00:07:05.319 --> 00:07:08.360 whether it's flat, open or closed, and it allows us 134 00:07:08.399 --> 00:07:11.120 to insert the components we think are in there, like 135 00:07:11.319 --> 00:07:13.480 dark energy and cold dark matter. 136 00:07:13.600 --> 00:07:15.959 So if you lose the florw description, if. 137 00:07:15.920 --> 00:07:19.519 The universe has proven to be fundamentally asymmetrical, the entire 138 00:07:19.560 --> 00:07:23.000 foundation of LAMB to CDM just collapses. It forces a 139 00:07:23.000 --> 00:07:27.079 complete mathematical overhaul. This is why it's so well sacred 140 00:07:27.120 --> 00:07:27.600 to the field. 141 00:07:27.680 --> 00:07:31.199 Okay, so cosmologists are already dealing with a pretty major 142 00:07:31.240 --> 00:07:34.040 problem in the model, one that often dominates the news, 143 00:07:34.600 --> 00:07:37.000 the Hubble tension, and that tells us the model is 144 00:07:37.000 --> 00:07:38.480 already under some strain. 145 00:07:38.920 --> 00:07:42.399 That's correct. The Hubble tension is the most widely publicized 146 00:07:42.439 --> 00:07:46.800 issue right now. It all centers on determining the Hubble constant, 147 00:07:46.959 --> 00:07:50.519 the exact rate at which the universe is currently expanding. 148 00:07:50.160 --> 00:07:52.720 And the conflict here is rooted in a disagreement between 149 00:07:52.720 --> 00:07:54.120 two different sets of measurements. 150 00:07:54.199 --> 00:07:57.040 Precisely, you have measurements of the expansion rate taken from 151 00:07:57.040 --> 00:07:58.199 the early universe. 152 00:07:57.920 --> 00:08:00.199 Which is mainly from the cosmic microwave. 153 00:07:59.759 --> 00:08:03.160 Back right, using data from the CMB, and then predicting 154 00:08:03.160 --> 00:08:06.079 what the current rate should be, and that prediction doesn't 155 00:08:06.079 --> 00:08:10.600 match the measurements we take from the nearby or more recent. 156 00:08:10.680 --> 00:08:13.959 Universe, where we're using things like type ia, supernovae and 157 00:08:14.120 --> 00:08:16.959 other local distance indicators exactly. 158 00:08:16.600 --> 00:08:19.519 And there's a disagreement roughly eight to ten percent. It's 159 00:08:19.560 --> 00:08:24.800 a conflict between early universe physics says X and late 160 00:08:24.920 --> 00:08:27.199 universe observation says why so. 161 00:08:27.160 --> 00:08:29.879 The Hubble tension suggests the problem with maybe what the 162 00:08:29.959 --> 00:08:33.559 universe is made of, maybe dark energy behaves differently, or 163 00:08:33.559 --> 00:08:36.399 there's a new relativistic particle we don't know about. 164 00:08:36.279 --> 00:08:38.080 Or a problem with how the universes evolves. 165 00:08:38.240 --> 00:08:41.799 Right, But the dipole anomaly, the subject of today, challenges 166 00:08:41.840 --> 00:08:43.039 something much much. 167 00:08:42.879 --> 00:08:46.639 Deeper it does, and this is the crucial distinction. The 168 00:08:46.720 --> 00:08:50.279 Hubble tension challenges the parameters and the contents of LAMB 169 00:08:50.279 --> 00:08:54.000 to CDM. It says, maybe the ingredients in our recipe 170 00:08:54.039 --> 00:08:55.639 are slightly wrong, but. 171 00:08:55.759 --> 00:08:57.840 The cosmic dipole anomaly. 172 00:08:57.480 --> 00:09:03.000 It challenges the very geometric basis the FFLRW description upon 173 00:09:03.080 --> 00:09:06.840 which LAMB to CDM is built. If the foundation itself 174 00:09:06.879 --> 00:09:10.960 is flawed, if the universe is fundamentally asymmetric, then trying 175 00:09:10.960 --> 00:09:13.120 to patch the cracks in the walls like the Hubble 176 00:09:13.120 --> 00:09:15.440 tension because the secondary issue. 177 00:09:15.120 --> 00:09:16.879 We're forced to ask a bigger question. 178 00:09:16.879 --> 00:09:19.919 Is the universe simply not symmetric enough for the flor 179 00:09:20.039 --> 00:09:22.120 W equations to even apply in the first place. 180 00:09:22.240 --> 00:09:25.480 Okay, so to understand how scientists actually test that core 181 00:09:25.519 --> 00:09:28.799 symmetry assumption, we have to look at the universe's baby picture, 182 00:09:29.080 --> 00:09:33.600 the cosmic microwave background or CMB. The cmba burelic radiation 183 00:09:33.799 --> 00:09:34.840 left over from the Big Bang. 184 00:09:34.919 --> 00:09:37.440 It's essentially the universe's first light. It was released about 185 00:09:37.480 --> 00:09:39.639 three hundred and eighty thousand years after the Big Bang, 186 00:09:39.759 --> 00:09:41.879 which is when the cosmos finally cooled down enough for 187 00:09:41.919 --> 00:09:45.000 electrons and protons to form neutral hydrogen atoms. 188 00:09:45.120 --> 00:09:48.240 And before that, the universe was just an opaque plasma. 189 00:09:48.159 --> 00:09:51.320 Completely opaque. You couldn't see through it, but after that moment, 190 00:09:51.919 --> 00:09:54.960 light could stream freely, and we observe that light today. 191 00:09:55.440 --> 00:09:58.360 It's been stretched by cosmic expansion over thirteen point eight 192 00:09:58.480 --> 00:10:02.440 billion years. Now it appears as a faint, uniform glow 193 00:10:02.480 --> 00:10:04.639 of microwaves baiting the entire sky. 194 00:10:04.960 --> 00:10:08.320 And when cosmologists first measured this glow with real precision, 195 00:10:08.399 --> 00:10:11.600 especially with satellites like WMAP and later PLANK, they were 196 00:10:11.600 --> 00:10:13.559 just stunned by its uniformity. 197 00:10:13.639 --> 00:10:16.440 Absolutely stunned. I mean, the CMB is uniform over the 198 00:10:16.600 --> 00:10:19.840 entire sky to within one part in one hundred thousand. 199 00:10:19.919 --> 00:10:20.600 Wow. 200 00:10:20.840 --> 00:10:24.879 That is an astonishing degree of smoothness, and that uniformity 201 00:10:25.039 --> 00:10:28.440 is the single biggest reason why cosmologists felt so confident 202 00:10:28.519 --> 00:10:31.320 in the perfectly symmetric FLRW model. 203 00:10:31.320 --> 00:10:34.399 The thinking being if the universe looked this smooth thirteen 204 00:10:34.480 --> 00:10:37.200 point eight billion years ago, it seems safe to assume 205 00:10:37.240 --> 00:10:40.000 it adheres to the rules of large scale homogeneity and 206 00:10:40.080 --> 00:10:41.320 isotropy precisely. 207 00:10:41.480 --> 00:10:44.360 But even this relic radiation has variations. 208 00:10:43.879 --> 00:10:47.000 The little ripples that eventually seated galaxy formation right. 209 00:10:47.080 --> 00:10:49.279 But the largest temperature difference we find is what we 210 00:10:49.320 --> 00:10:51.519 call the CMB dipole. Anisotropye. 211 00:10:51.519 --> 00:10:54.559 Okay, so anisotropy just means not isotropic, looks different in 212 00:10:54.559 --> 00:10:56.080 different directions exactly. 213 00:10:56.240 --> 00:11:00.399 And the CMB dipole anisotropy is the largest temperature trast 214 00:11:00.440 --> 00:11:04.279 we see. It's a slight but very measurable difference where 215 00:11:04.279 --> 00:11:06.480 one side of the sky is hotter and the opposite 216 00:11:06.519 --> 00:11:07.240 side is cooler. 217 00:11:07.360 --> 00:11:10.519 And the magnitude of this difference is about one part 218 00:11:10.559 --> 00:11:13.240 in a thousand. That's a huge signal compared to the 219 00:11:13.279 --> 00:11:14.360 overall smoothness. 220 00:11:14.399 --> 00:11:16.799 It is a very big signal. You don't even need 221 00:11:16.879 --> 00:11:20.559 super advanced equipment to detect it. But and this is crucial, 222 00:11:21.080 --> 00:11:25.320 this specific large variation does not challenge LAMB to CDM 223 00:11:25.399 --> 00:11:25.879 on its own. 224 00:11:26.080 --> 00:11:27.399 In fact, it's expected. 225 00:11:27.639 --> 00:11:30.759 It's entirely expected and necessary within the standard model. 226 00:11:30.919 --> 00:11:33.919 Okay, So why is a huge hot spot and a 227 00:11:34.000 --> 00:11:36.759 huge cold spot in the CMB actually expected in a 228 00:11:36.759 --> 00:11:39.519 symmetrical universe. That sounds counterintuitive, it. 229 00:11:39.480 --> 00:11:41.679 Does, but it comes down to the principle of relativity 230 00:11:41.720 --> 00:11:44.360 in our own motion. The standard interpretation of the CMB 231 00:11:44.519 --> 00:11:47.759 dipole anisotropy is that it's entirely due to our local 232 00:11:47.799 --> 00:11:49.840 motion through the universe's rest frame. 233 00:11:50.080 --> 00:11:52.120 The rest frame being the frame in which the CMB 234 00:11:52.200 --> 00:11:55.840 would appear perfectly isotropic exactly. Let's use that classic analogy 235 00:11:55.919 --> 00:11:56.759 running in the rain. 236 00:11:56.879 --> 00:11:59.840 Right, So if you are standing still, the rain seems 237 00:11:59.879 --> 00:12:02.639 to hit you perfectly vertically from straight above. 238 00:12:02.720 --> 00:12:04.559 But if you start running forward. 239 00:12:04.320 --> 00:12:06.440 The drops in front of you hit your face faster 240 00:12:06.519 --> 00:12:10.639 and more frequently. That's the relativistic Doppler effect. As our 241 00:12:10.679 --> 00:12:13.679 solar system and the Milky Way galaxy move relative to 242 00:12:13.720 --> 00:12:17.559 the cmb's universal reference frame, the light from the CMB 243 00:12:17.720 --> 00:12:20.960 in the direction of our motion gets blue shifted. 244 00:12:20.639 --> 00:12:23.559 So it's crammed together and making it seem slightly hotter right. 245 00:12:23.960 --> 00:12:27.039 And conversely, the light from the opposite direction, the direction 246 00:12:27.080 --> 00:12:30.039 we're running away from, gets red shifted or stretched out, 247 00:12:30.279 --> 00:12:31.480 making it seem slightly cooler. 248 00:12:31.519 --> 00:12:33.279 Yeah, we can actually calculate our speed from that. 249 00:12:33.399 --> 00:12:37.240 We can. The strength of this dipole signal allows cosmologists 250 00:12:37.320 --> 00:12:40.720 to calculate our absolute velocity relative to the rest frame 251 00:12:40.759 --> 00:12:44.960 of the early universe. The consensus result derived from the 252 00:12:45.000 --> 00:12:47.840 precise Plank satellite data is that our local group of 253 00:12:47.879 --> 00:12:50.919 galaxies is cruising through space at roughly three hundred and 254 00:12:50.960 --> 00:12:52.279 seventy kilometers per second. 255 00:12:52.399 --> 00:12:54.000 Wow per second per. 256 00:12:53.879 --> 00:12:56.480 Second towards a specific point in the sky near the 257 00:12:56.519 --> 00:12:57.360 constellation Hydra. 258 00:12:57.639 --> 00:13:00.679 So, just to be clear, the small the only symmetry 259 00:13:00.720 --> 00:13:03.080 we see in the CMB is entirely attributed to the 260 00:13:03.120 --> 00:13:06.360 fact that we are moving. Yes, it's an observational effect 261 00:13:06.519 --> 00:13:10.440 tied to us the observers, not a fundamental flaw in 262 00:13:10.480 --> 00:13:11.919 the universe's geometric structure. 263 00:13:12.080 --> 00:13:15.120 That's the consensus interpretation, and it holds up beautifully for 264 00:13:15.159 --> 00:13:19.159 the CMB data. However, here's where the deep philosophical question 265 00:13:19.240 --> 00:13:23.200 comes in. Okay, if the universe is truly governed by 266 00:13:23.200 --> 00:13:28.440 the symmetric FLRW description, then every large scale observable component 267 00:13:28.480 --> 00:13:31.559 of the cosmos must adhere to the same physical rules 268 00:13:31.600 --> 00:13:33.000 dictated by that symmetry. 269 00:13:33.080 --> 00:13:35.159 So the core test then is whether the rest of 270 00:13:35.159 --> 00:13:37.519 the universe agrees with that imposed asymmetry. 271 00:13:37.559 --> 00:13:40.480 That is the ultimate consistency check. If we are truly 272 00:13:40.519 --> 00:13:43.080 moving at three hundred and seventy kilometers per second relative 273 00:13:43.120 --> 00:13:46.720 to the early universe, we should see all truly distant structures, 274 00:13:47.080 --> 00:13:50.679 the distribution of galaxies, the brightness of quasars respond to 275 00:13:50.720 --> 00:13:53.440 that speed in a predictable, uniform. 276 00:13:53.000 --> 00:13:55.000 And quantifiable way, and if they don't. 277 00:13:55.159 --> 00:13:57.759 If they don't, then our movement isn't the whole story 278 00:13:58.240 --> 00:14:00.440 or the GMAC model we're using the cat aculate these 279 00:14:00.440 --> 00:14:01.919 effects is fundamentally broken. 280 00:14:02.080 --> 00:14:06.039 And this realization that the CMB dipole mandates a corresponding 281 00:14:06.039 --> 00:14:09.200 dipole in the matterfield is what leads us directly into 282 00:14:09.200 --> 00:14:12.960 the most critical experiment designed to test cosmic symmetry. So 283 00:14:13.039 --> 00:14:15.879 now we get to the specific scientific challenge designed to 284 00:14:15.960 --> 00:14:20.200 test this required cosmic consistency, the Elis Baldwin test. 285 00:14:20.440 --> 00:14:24.639 Right back in nineteen eighty four, George Ellis and John Baldwin, 286 00:14:25.080 --> 00:14:28.440 two figures known for their really rigorous application of general 287 00:14:28.440 --> 00:14:31.759 relativity to cosmology, proposed this specific check. 288 00:14:31.600 --> 00:14:33.600 And the question was sharp and simple. 289 00:14:33.840 --> 00:14:37.879 Very if the symmetric FLRW framework is correct, then the 290 00:14:37.960 --> 00:14:40.879 variations we observe in the early Universe's light the CMB 291 00:14:41.000 --> 00:14:44.840 dipole must be perfectly reflected by a similar dipole anisotropy 292 00:14:45.279 --> 00:14:48.440 in the sky distribution of distant astronomical sources. 293 00:14:48.039 --> 00:14:49.679 The matter dipole, the matter dipole. 294 00:14:49.720 --> 00:14:52.159 They weren't just proposing a measurement, they were proposing a 295 00:14:52.200 --> 00:14:55.759 mandatory relationship. It puts the light field and the matterfield 296 00:14:55.960 --> 00:14:59.200 into direct confrontation with that core FLRW assumption. 297 00:14:59.320 --> 00:15:03.399 It's the ultimate benchmark test for the standard model's geometric foundation. 298 00:15:03.799 --> 00:15:06.679 I think. So you have the radiation field, this pristine 299 00:15:06.799 --> 00:15:09.840 information from thirteen point eight billion years ago telling us 300 00:15:09.879 --> 00:15:12.720 our velocity, and then you have the matter field, the 301 00:15:12.799 --> 00:15:16.759 distribution of trillions of galaxies stretching across vast cosmic distances, 302 00:15:17.120 --> 00:15:20.440 which should, in theory react in a very calculated way 303 00:15:20.480 --> 00:15:21.320 to that velocity. 304 00:15:21.720 --> 00:15:24.399 Now, to perform this test correctly, the data has to 305 00:15:24.440 --> 00:15:28.080 satisfy a really strict requirement. The astronomical sources you use 306 00:15:28.159 --> 00:15:29.360 must be very distant. 307 00:15:29.399 --> 00:15:32.200 This point cannot be overstated. We need to look far 308 00:15:32.360 --> 00:15:34.919 enough out that the universe has smoothed out that it 309 00:15:35.000 --> 00:15:37.360 meets that large scale homogeneity assumption. 310 00:15:37.559 --> 00:15:40.559 So if you use sources that are too nearby. 311 00:15:40.360 --> 00:15:43.080 If you use sources that are too nearby, say within 312 00:15:43.120 --> 00:15:46.080 our local superpluster, which might be a few hundred million 313 00:15:46.159 --> 00:15:48.919 light years across, you run the risk of measuring what 314 00:15:48.960 --> 00:15:51.559 we call a spurious clustering dipole. 315 00:15:51.600 --> 00:15:54.360 Okay, let's break that down. Spurrious is meaning what exactly. 316 00:15:54.600 --> 00:15:58.320 Spurrious just means false or misleading in the nearby universe. 317 00:15:58.360 --> 00:16:01.399 Gravity hasn't finished its work yet. You know, galaxies are 318 00:16:01.440 --> 00:16:05.440 still clumped together into filaments and walls and these immense voids. 319 00:16:05.080 --> 00:16:07.200 The cosmic web, the cosmic web. 320 00:16:07.559 --> 00:16:09.159 So if we just happen to be sitting on the 321 00:16:09.240 --> 00:16:12.559 edge of a massive over density of galaxies, we might 322 00:16:12.639 --> 00:16:16.600 measure an apparent dipole simply because there are more galaxies 323 00:16:16.639 --> 00:16:18.200 to our left than to our right. 324 00:16:18.240 --> 00:16:21.120 And that asymmetry would just be a local effect exactly. 325 00:16:21.440 --> 00:16:24.440 It would be tied to the small scale clumpiness of matter, 326 00:16:25.120 --> 00:16:28.399 not a universal effect dictated by our motion through the 327 00:16:28.440 --> 00:16:29.159 CMB frame. 328 00:16:29.360 --> 00:16:33.840 So to truly test the universe's foundational structure in its symmetry, 329 00:16:33.919 --> 00:16:36.840 we need sources so remote that we're averaging over many, 330 00:16:36.840 --> 00:16:38.080 many billions of light years. 331 00:16:38.200 --> 00:16:42.200 That's the only way it ensures that any dipole signal 332 00:16:42.240 --> 00:16:45.240 we see reflects the deep, large scale structure of the 333 00:16:45.279 --> 00:16:47.919 cosmos rather than some local fluctuation. 334 00:16:48.200 --> 00:16:51.320 And this is why researchers focus on things like quasars. 335 00:16:50.960 --> 00:16:54.799 Quasars and distant radio galaxies. They're excellent deep space probes 336 00:16:54.799 --> 00:16:57.279 because they're so incredibly luminous. They allow us to gain 337 00:16:57.320 --> 00:17:00.519 the statistical power necessary to average out those local in 338 00:17:00.600 --> 00:17:03.480 homogeneities and see what the universe is really doing on 339 00:17:03.519 --> 00:17:07.079 scales large enough to satisfy that FLRW. 340 00:17:06.519 --> 00:17:10.119 Premis so, the hypothesis is actually elegantly simple. It is, 341 00:17:10.440 --> 00:17:15.519 if the FLRW metric is correct, the dipole amplitude calculated 342 00:17:15.519 --> 00:17:19.440 from the distant matter field must quantitatively match the dipole 343 00:17:19.480 --> 00:17:21.119 amplitude observed in the CMB. 344 00:17:21.359 --> 00:17:24.880 They have to be consistent in both direction and magnitude. 345 00:17:24.960 --> 00:17:29.960 And conversely, if there's discord a measurable mismatch between the 346 00:17:30.000 --> 00:17:34.839 two dipole signals, that would directly challenge the fundamental FLRW. 347 00:17:34.400 --> 00:17:37.160 Description and put the entire standard model into question. 348 00:17:37.440 --> 00:17:40.440 It's an incredible test, and it's worth noting too the 349 00:17:40.599 --> 00:17:43.160 huge gap in time between the proposal of this test 350 00:17:43.200 --> 00:17:45.559 in nineteen eighty four and its actual execution. 351 00:17:45.680 --> 00:17:49.119 Oh absolutely. When Ellis in Baldwin proposed it, it was almost 352 00:17:49.119 --> 00:17:53.319 a theoretical challenge, a thought experiment. The observational data simply 353 00:17:53.319 --> 00:17:56.119 didn't exist to reach the necessary statistical precision. 354 00:17:56.319 --> 00:17:58.480 We just couldn't see far enough or wide enough, right. 355 00:17:58.480 --> 00:18:00.799 We didn't have all sky surveys is with high enough 356 00:18:00.799 --> 00:18:04.000 sensitivity and enough depth to measure hundreds of thousands of 357 00:18:04.000 --> 00:18:07.839 truly distant, statistically independent sources. It has only been in 358 00:18:07.839 --> 00:18:10.319 the last what five or six years, thanks to modern 359 00:18:10.400 --> 00:18:13.640 radio telescopes and deep infra red surveys, that we finally 360 00:18:13.680 --> 00:18:17.240 accumulated the precise catalogs required to run this critical check. 361 00:18:17.359 --> 00:18:20.799 So we're truly moving from the theoretical foundation to the 362 00:18:20.880 --> 00:18:24.119 actual measured reality we are, and the results of that 363 00:18:24.160 --> 00:18:28.079 measured reality, according to the research, are not kind to 364 00:18:28.119 --> 00:18:29.119 the standard model. 365 00:18:29.400 --> 00:18:31.759 So let's just state the core finding as clearly as 366 00:18:31.799 --> 00:18:35.720 possible as it's synthesized in this review. The universe fails 367 00:18:35.799 --> 00:18:37.079 the Ellis Baldwin test. 368 00:18:37.240 --> 00:18:38.240 These it completely. 369 00:18:38.359 --> 00:18:41.599 The variation observed in distant matter does not match the 370 00:18:41.680 --> 00:18:44.839 variation observed in the CMB, and this mismatch is what 371 00:18:44.839 --> 00:18:47.160 we call the cosmic dipole anomaly. 372 00:18:47.200 --> 00:18:49.559 And it's a quantitative failure, right, and not just a 373 00:18:49.680 --> 00:18:50.440 vague feel. 374 00:18:50.319 --> 00:18:54.000 Oh, absolutely quantitative. If we calculate the expected dipole anisotropy 375 00:18:54.440 --> 00:18:57.160 in matter based purely on the velocity we get from 376 00:18:57.160 --> 00:19:00.720 the CMB, that three hundred and seventy kilometers per secon movement, and. 377 00:19:00.680 --> 00:19:03.680 Then we measure the actual dipole anisotropy from the distribution 378 00:19:03.759 --> 00:19:05.200 of distant radio galaxies. 379 00:19:05.359 --> 00:19:08.839 The expected and the measured numbers simply don't align, and. 380 00:19:08.759 --> 00:19:13.079 They mismatch in a very specific and telling way. 381 00:19:13.279 --> 00:19:16.079 They do. The directional data is the direction of the 382 00:19:16.079 --> 00:19:19.359 dipole is generally consistent. The hot side of the CMB, 383 00:19:19.480 --> 00:19:22.960 the direction we're moving into it aligns roughly with the 384 00:19:22.960 --> 00:19:26.200 direction where the distant matter sources seem to be slightly 385 00:19:26.200 --> 00:19:26.880 more clustered. 386 00:19:27.119 --> 00:19:28.480 Okay, so that part makes sense. 387 00:19:28.519 --> 00:19:31.960 That directional consistency makes sense if our local motion is 388 00:19:32.000 --> 00:19:33.000 part of the explanation. 389 00:19:33.160 --> 00:19:36.319 But it's the amplitude, the strength of the signal that's 390 00:19:36.359 --> 00:19:37.519 where the failure lies. 391 00:19:37.599 --> 00:19:42.039 Precisely, the measured amplitude of the matter dipole is consistently 392 00:19:42.279 --> 00:19:45.759 across multiple studies and different source catalogs, found to be 393 00:19:45.799 --> 00:19:49.440 several times larger than the amplitude predicted purely by our 394 00:19:49.480 --> 00:19:50.519 CMB derived motion. 395 00:19:50.920 --> 00:19:53.319 So, just to put that in perspective, if the CMB 396 00:19:53.440 --> 00:19:56.079 dipole says you are moving at three hundred and seventy 397 00:19:56.119 --> 00:19:59.720 kilometers per second, the distant matter dipole is essentially shouting 398 00:19:59.720 --> 00:20:03.200 back no. Based on how lopsided I look, you should 399 00:20:03.200 --> 00:20:06.119 be moving at something like fifteen hundred kilometers per second. 400 00:20:05.920 --> 00:20:08.559 Or even two thousand. That's a perfect way to visualize 401 00:20:08.559 --> 00:20:11.200