1 00:00:00,000 --> 00:00:01,680 Picture this, you're an astronomer. 2 00:00:03,020 --> 00:00:06,720 Back in 1998, you're peering deep into space, 3 00:00:06,720 --> 00:00:11,260 expecting to find evidence that the universe's expansion 4 00:00:11,260 --> 00:00:12,100 is slowing down. 5 00:00:12,100 --> 00:00:12,960 Right, because of gravity. 6 00:00:12,960 --> 00:00:14,300 Due to gravity, exactly. 7 00:00:14,300 --> 00:00:17,200 And instead, you discover the opposite. 8 00:00:17,200 --> 00:00:18,340 The universe is speeding up. 9 00:00:18,340 --> 00:00:20,240 It's like throwing a ball up in the air 10 00:00:20,240 --> 00:00:21,980 and watching it accelerate upwards 11 00:00:21,980 --> 00:00:24,040 instead of falling back down. 12 00:00:24,040 --> 00:00:25,440 That's the mind-blowing discovery 13 00:00:25,440 --> 00:00:28,140 that led to the concept of dark energy. 14 00:00:28,140 --> 00:00:30,720 Welcome to Cosmos in a Podspace and Astronomy series. 15 00:00:30,720 --> 00:00:31,560 Absolutely. 16 00:00:31,560 --> 00:00:33,600 So we're diving into the mystery of dark energy. 17 00:00:33,600 --> 00:00:34,440 Okay. 18 00:00:34,440 --> 00:00:36,000 This invisible force that seems to be 19 00:00:36,000 --> 00:00:37,360 pushing everything apart. 20 00:00:37,360 --> 00:00:39,760 It makes up a whopping 68% of the universe. 21 00:00:39,760 --> 00:00:40,780 Wow. 22 00:00:40,780 --> 00:00:43,760 But we have no idea what it actually is. 23 00:00:43,760 --> 00:00:44,600 Yeah. 24 00:00:44,600 --> 00:00:45,980 It's like trying to understand the engine of a car 25 00:00:45,980 --> 00:00:47,800 by only looking at the exhaust fumes. 26 00:00:47,800 --> 00:00:48,960 That's a great analogy. 27 00:00:48,960 --> 00:00:51,100 The discovery of dark energy really shook 28 00:00:51,100 --> 00:00:52,980 the foundations of cosmology. 29 00:00:52,980 --> 00:00:54,700 It challenged our understanding of gravity 30 00:00:54,700 --> 00:00:57,240 and forced us to consider entirely new possibilities 31 00:00:57,240 --> 00:00:58,920 about the nature of the universe. 32 00:00:58,920 --> 00:01:01,640 It's like realizing there's a whole other set of rules 33 00:01:01,640 --> 00:01:04,680 governing the cosmos that we're just beginning to glimpse. 34 00:01:04,680 --> 00:01:05,520 Right. 35 00:01:05,520 --> 00:01:07,400 So how did scientists even stumble upon 36 00:01:07,400 --> 00:01:09,340 this invisible force in the first place? 37 00:01:09,340 --> 00:01:12,180 Well, it all started with those distant exploding stars 38 00:01:12,180 --> 00:01:13,240 called supernovae. 39 00:01:13,240 --> 00:01:14,080 Okay. 40 00:01:14,080 --> 00:01:16,940 Astronomers were using them as standard candles objects 41 00:01:16,940 --> 00:01:20,640 with a known brightness to measure cosmic distances. 42 00:01:20,640 --> 00:01:23,080 But they noticed something strange. 43 00:01:23,080 --> 00:01:26,200 These supernovae were much fainter than expected, 44 00:01:26,200 --> 00:01:29,440 which meant they were farther away than they should have been 45 00:01:29,440 --> 00:01:32,560 based on the universe's presumed rate of expansion. 46 00:01:32,560 --> 00:01:34,360 So it's like looking at a streetlight and realizing 47 00:01:34,360 --> 00:01:35,920 it's much dimmer than it should be. 48 00:01:35,920 --> 00:01:36,760 Exactly. 49 00:01:36,760 --> 00:01:38,240 Meaning it must be farther away than you thought. 50 00:01:38,240 --> 00:01:39,080 Exactly. 51 00:01:39,080 --> 00:01:40,700 And that's how astronomers realized 52 00:01:40,700 --> 00:01:43,120 that the universe's expansion wasn't slowing down 53 00:01:43,120 --> 00:01:44,040 as predicted. 54 00:01:44,040 --> 00:01:45,680 It was actually speeding up. 55 00:01:45,680 --> 00:01:46,520 Wow. 56 00:01:46,520 --> 00:01:49,500 This unexpected acceleration pointed to the presence 57 00:01:49,500 --> 00:01:53,000 of some unknown force counteracting gravity, 58 00:01:53,000 --> 00:01:54,920 which we now call dark energy. 59 00:01:54,920 --> 00:01:55,960 That's incredible. 60 00:01:55,960 --> 00:01:56,800 Yeah. 61 00:01:56,800 --> 00:01:59,880 But supernovae aren't the only evidence for dark energy. 62 00:01:59,880 --> 00:02:00,720 Right. 63 00:02:00,720 --> 00:02:03,160 It's not like scientists base it such a huge concept 64 00:02:03,160 --> 00:02:04,760 on just one observation. 65 00:02:04,760 --> 00:02:06,280 You're absolutely right. 66 00:02:06,280 --> 00:02:08,320 There are multiple lines of evidence, 67 00:02:08,320 --> 00:02:11,540 like pieces of a cosmic puzzle that all fit together 68 00:02:11,540 --> 00:02:14,080 to reveal the picture of dark energy. 69 00:02:14,080 --> 00:02:16,000 So what are some of these other pieces of the puzzle? 70 00:02:16,000 --> 00:02:19,520 Well, there's the Cosmic Microwave Background or CMB, 71 00:02:19,520 --> 00:02:21,680 which is like the afterglow of the Big Bang. 72 00:02:21,680 --> 00:02:22,520 Okay. 73 00:02:22,520 --> 00:02:24,840 This faint radiation that permeates the universe. 74 00:02:24,840 --> 00:02:25,680 Yeah. 75 00:02:25,680 --> 00:02:27,640 It's the information about its early composition 76 00:02:27,640 --> 00:02:28,480 and evolution. 77 00:02:28,480 --> 00:02:29,300 Uh-huh. 78 00:02:29,300 --> 00:02:30,140 And guess what? 79 00:02:30,140 --> 00:02:31,720 The patterns in the CMB also point 80 00:02:31,720 --> 00:02:33,880 to the presence of dark energy. 81 00:02:33,880 --> 00:02:34,700 Wow. 82 00:02:34,700 --> 00:02:35,540 So we're talking about signals 83 00:02:35,540 --> 00:02:36,760 from the very beginning of the universe. 84 00:02:36,760 --> 00:02:37,600 Yes. 85 00:02:37,600 --> 00:02:39,080 Confirming what we see with supernovae 86 00:02:39,080 --> 00:02:40,280 billions of years later. 87 00:02:40,280 --> 00:02:41,200 Exactly. 88 00:02:41,200 --> 00:02:43,400 It's remarkable how these independent lines 89 00:02:43,400 --> 00:02:46,280 of evidence converge, but there's more. 90 00:02:46,280 --> 00:02:47,120 Okay. 91 00:02:47,120 --> 00:02:48,320 The way galaxies are clumped together 92 00:02:48,320 --> 00:02:50,000 and spread out across the universe. 93 00:02:50,000 --> 00:02:50,840 Okay. 94 00:02:50,840 --> 00:02:52,360 What we call the large scale structure 95 00:02:52,360 --> 00:02:55,240 also provides clues about dark energy. 96 00:02:55,240 --> 00:02:57,640 So even the way galaxies are arranged 97 00:02:57,640 --> 00:02:59,960 tells us something about this invisible force. 98 00:02:59,960 --> 00:03:01,160 It does. 99 00:03:01,160 --> 00:03:03,680 Imagine you're looking at a spider web, 100 00:03:03,680 --> 00:03:05,480 the pattern of the web, 101 00:03:05,480 --> 00:03:08,000 how the threads are connected and spaced out. 102 00:03:08,000 --> 00:03:10,720 Tells you something about the forces that created it. 103 00:03:10,720 --> 00:03:13,960 Similarly, the large scale structure of the universe 104 00:03:13,960 --> 00:03:15,880 tells us about the forces that have shaped it 105 00:03:15,880 --> 00:03:19,440 over billions of years, including dark energy. 106 00:03:19,440 --> 00:03:21,440 It's fascinating how scientists can extract 107 00:03:21,440 --> 00:03:25,640 such profound insights from seemingly simple observations. 108 00:03:25,640 --> 00:03:27,760 And then there's another fascinating piece of evidence 109 00:03:27,760 --> 00:03:30,000 called baryon acoustic oscillations, 110 00:03:30,000 --> 00:03:31,920 or BAOs for short. 111 00:03:31,920 --> 00:03:33,600 BAOs, you mentioned that earlier, 112 00:03:33,600 --> 00:03:35,360 but what are those exactly? 113 00:03:35,360 --> 00:03:38,280 Imagine sound waves traveling through the early universe. 114 00:03:38,280 --> 00:03:39,120 Okay. 115 00:03:39,120 --> 00:03:41,200 Creating ripples of density variations. 116 00:03:41,200 --> 00:03:43,920 These ripples frozen in time as the universe expanded 117 00:03:43,920 --> 00:03:46,360 act like a giant cosmic ruler, 118 00:03:46,360 --> 00:03:49,400 allowing us to measure distances across the cosmos. 119 00:03:49,400 --> 00:03:51,040 It's like looking at the rings of a tree 120 00:03:51,040 --> 00:03:53,680 and using them to determine its age and growth patterns. 121 00:03:53,680 --> 00:03:54,520 Precisely. 122 00:03:54,520 --> 00:03:57,440 And the spacing of these BAOs, these cosmic ripples, 123 00:03:57,440 --> 00:03:59,120 tells us that the expansion of the universe 124 00:03:59,120 --> 00:04:00,800 is indeed accelerating, 125 00:04:00,800 --> 00:04:02,960 confirming the presence of dark energy. 126 00:04:02,960 --> 00:04:05,040 So we've got supernovae, the CMB. 127 00:04:05,040 --> 00:04:05,880 Yes. 128 00:04:05,880 --> 00:04:07,760 The large scale structure of galaxies. 129 00:04:07,760 --> 00:04:08,600 Right. 130 00:04:08,600 --> 00:04:11,720 And these BAOs all pointing to the same conclusion, 131 00:04:11,720 --> 00:04:15,120 dark energy is real and it's pushing the universe apart. 132 00:04:15,120 --> 00:04:16,200 That's right. 133 00:04:16,200 --> 00:04:19,440 The evidence is overwhelming, but now the big question is, 134 00:04:19,440 --> 00:04:22,160 what exactly is this mysterious force? 135 00:04:22,160 --> 00:04:23,160 Yes. 136 00:04:23,160 --> 00:04:25,280 We know it exists, but what is it made of? 137 00:04:25,280 --> 00:04:26,600 Where does it come from? 138 00:04:26,600 --> 00:04:27,640 What are its properties? 139 00:04:27,640 --> 00:04:29,360 It's like finding a strange new creature 140 00:04:29,360 --> 00:04:31,880 and trying to figure out where it fits in the tree of life. 141 00:04:31,880 --> 00:04:34,800 That's where things get really interesting. 142 00:04:34,800 --> 00:04:36,880 And that's what we'll delve into next. 143 00:04:36,880 --> 00:04:38,800 Welcome back to Cosmos in a Pod. 144 00:04:38,800 --> 00:04:41,600 Where we're grappling with the enigma of dark energy. 145 00:04:41,600 --> 00:04:42,480 Yeah. 146 00:04:42,480 --> 00:04:45,080 Before we went away, 147 00:04:45,080 --> 00:04:46,920 we were talking about how astronomers discovered 148 00:04:46,920 --> 00:04:49,600 this invisible force that's pushing the universe apart. 149 00:04:49,600 --> 00:04:50,320 Right. 150 00:04:50,320 --> 00:04:52,160 We discussed the multiple lines of evidence 151 00:04:52,160 --> 00:04:53,640 from those dimming supernovae 152 00:04:53,640 --> 00:04:56,840 to the cosmic microwave background radiation, 153 00:04:56,840 --> 00:04:59,040 all pointing to an accelerating universe. 154 00:04:59,040 --> 00:05:01,400 So we've established that dark energy is out there. 155 00:05:01,400 --> 00:05:02,240 Right. 156 00:05:02,240 --> 00:05:04,680 But what's really fascinating is that it's forcing physicists 157 00:05:04,680 --> 00:05:07,280 to rethink some of the most fundamental ideas 158 00:05:07,280 --> 00:05:08,120 about the universe. 159 00:05:08,120 --> 00:05:08,960 Yeah. 160 00:05:08,960 --> 00:05:11,360 It's like finding a missing piece of a puzzle 161 00:05:11,360 --> 00:05:12,880 that doesn't quite fit, 162 00:05:12,880 --> 00:05:14,200 making you question the whole picture. 163 00:05:14,200 --> 00:05:15,040 Absolutely. 164 00:05:15,040 --> 00:05:15,880 Yeah. 165 00:05:15,880 --> 00:05:18,360 So theories like Einstein's theory of general relativity 166 00:05:18,360 --> 00:05:20,520 and the standard model of particle physics 167 00:05:20,520 --> 00:05:22,120 are incredibly successful 168 00:05:22,120 --> 00:05:24,440 in explaining a vast range of phenomena, 169 00:05:24,440 --> 00:05:26,920 but they don't fully account for dark energy. 170 00:05:26,920 --> 00:05:29,160 It's like having a beautifully designed machine 171 00:05:29,160 --> 00:05:31,360 where one crucial gear is missing. 172 00:05:31,360 --> 00:05:32,960 So what are the leading contenders 173 00:05:32,960 --> 00:05:35,880 for explaining this mysterious force? 174 00:05:35,880 --> 00:05:38,880 What are some of the theories physicists are exploring? 175 00:05:38,880 --> 00:05:41,680 Well, one idea is the cosmological constant. 176 00:05:41,680 --> 00:05:42,520 So? 177 00:05:42,520 --> 00:05:44,240 A concept that Einstein himself introduced 178 00:05:44,240 --> 00:05:46,160 and then famously rejected, 179 00:05:46,160 --> 00:05:48,160 calling it his biggest blunder. 180 00:05:48,160 --> 00:05:49,480 Ironically, it might turn out to be 181 00:05:49,480 --> 00:05:51,240 one of his most prescient insights. 182 00:05:51,240 --> 00:05:52,080 Okay. 183 00:05:52,080 --> 00:05:53,920 So what is the cosmological constant 184 00:05:53,920 --> 00:05:56,440 and how does it relate to dark energy? 185 00:05:56,440 --> 00:05:58,960 Imagine that empty space itself 186 00:05:58,960 --> 00:06:01,160 has a certain inherent energy, 187 00:06:01,160 --> 00:06:03,200 a kind of baseline energy density 188 00:06:03,200 --> 00:06:05,360 that permeates the entire universe. 189 00:06:05,360 --> 00:06:07,880 That's the essence of the cosmological constant. 190 00:06:07,880 --> 00:06:10,240 And this energy, even in the absence of matter, 191 00:06:10,240 --> 00:06:12,440 could exert a repulsive force, 192 00:06:12,440 --> 00:06:14,480 driving the expansion of the universe. 193 00:06:14,480 --> 00:06:16,600 So empty space isn't actually empty. 194 00:06:16,600 --> 00:06:18,520 It's like saying even a vacuum 195 00:06:18,520 --> 00:06:20,760 has a tiny bit of energy pushing outwards. 196 00:06:20,760 --> 00:06:21,960 Exactly. 197 00:06:21,960 --> 00:06:24,080 It's a mind-bending idea, 198 00:06:24,080 --> 00:06:25,880 but it fits surprisingly well 199 00:06:25,880 --> 00:06:27,200 with some of our observations 200 00:06:27,200 --> 00:06:29,400 of the universe's acceleration. 201 00:06:29,400 --> 00:06:31,480 However, there's a big problem. 202 00:06:31,480 --> 00:06:32,360 What's that? 203 00:06:32,360 --> 00:06:34,480 The value of the cosmological constant 204 00:06:34,480 --> 00:06:36,280 predicted by quantum field theory 205 00:06:36,280 --> 00:06:40,400 is vastly larger than the value we infer from observations, 206 00:06:40,400 --> 00:06:42,280 like ridiculously larger. 207 00:06:42,280 --> 00:06:44,960 It's one of the biggest discrepancies in all of physics. 208 00:06:44,960 --> 00:06:45,800 Okay. 209 00:06:45,800 --> 00:06:47,480 So if the cosmological constant 210 00:06:47,480 --> 00:06:49,880 is causing this acceleration, 211 00:06:49,880 --> 00:06:51,760 why is there such a huge mismatch 212 00:06:51,760 --> 00:06:53,640 between theory and observation? 213 00:06:53,640 --> 00:06:55,200 That's a million dollar question. 214 00:06:55,200 --> 00:06:57,400 It's a major headache for physicists. 215 00:06:57,400 --> 00:06:58,800 Some theorists believe it's a sign 216 00:06:58,800 --> 00:07:01,320 that we need to modify our understanding of gravity, 217 00:07:01,320 --> 00:07:02,680 perhaps coming up with a new theory 218 00:07:02,680 --> 00:07:05,320 that goes beyond Einstein's general relativity. 219 00:07:05,320 --> 00:07:06,200 Modified gravity. 220 00:07:06,200 --> 00:07:08,320 So maybe our understanding of how gravity works 221 00:07:08,320 --> 00:07:09,160 is incomplete. 222 00:07:09,160 --> 00:07:10,000 Exactly. 223 00:07:10,000 --> 00:07:11,680 It's possible that at cosmic scales, 224 00:07:11,680 --> 00:07:14,040 gravity behaves differently than we expect. 225 00:07:14,040 --> 00:07:16,440 There are many modified gravity theories out there, 226 00:07:16,440 --> 00:07:18,440 each with his own quirks and predictions. 227 00:07:18,440 --> 00:07:22,080 So if the cosmological constant isn't the answer, 228 00:07:22,080 --> 00:07:23,360 what are some of the other possibilities? 229 00:07:23,360 --> 00:07:26,200 Well, another intriguing idea is called quintessence. 230 00:07:26,200 --> 00:07:28,680 Instead of a constant energy density, 231 00:07:28,680 --> 00:07:30,840 quintessence proposes that dark energy 232 00:07:30,840 --> 00:07:33,760 is a dynamic field that can change over time. 233 00:07:33,760 --> 00:07:36,720 So dark energy could be getting stronger or weaker 234 00:07:36,720 --> 00:07:38,080 as the universe evolves. 235 00:07:38,080 --> 00:07:39,160 Precisely. 236 00:07:39,160 --> 00:07:40,720 And this variation in strength 237 00:07:40,720 --> 00:07:42,160 could have profound effects 238 00:07:42,160 --> 00:07:43,760 on the universe's expansion rate 239 00:07:43,760 --> 00:07:45,760 and ultimately its fate. 240 00:07:45,760 --> 00:07:49,080 Imagine a cosmic fluid that permeates all of space 241 00:07:49,080 --> 00:07:51,800 and its density and pressure can fluctuate, 242 00:07:51,800 --> 00:07:54,040 influencing the expansion of the universe. 243 00:07:54,040 --> 00:07:57,320 It's almost like dark energy has a mind of its own, 244 00:07:57,320 --> 00:07:59,400 shaping the destiny of the cosmos. 245 00:07:59,400 --> 00:08:00,880 That's a poetic way to put it. 246 00:08:00,880 --> 00:08:03,120 And then there are even more exotic possibilities, 247 00:08:03,120 --> 00:08:05,920 ideas that push the boundaries of our current understanding. 248 00:08:05,920 --> 00:08:06,760 Like what? 249 00:08:06,760 --> 00:08:08,520 Well, some theories suggest that dark energy 250 00:08:08,520 --> 00:08:11,000 might be a manifestation of extra dimensions 251 00:08:11,000 --> 00:08:13,400 curled up and hidden from our perception. 252 00:08:13,400 --> 00:08:15,800 Or it could be some kind of emergent phenomenon, 253 00:08:15,800 --> 00:08:17,720 a property of space-time itself, 254 00:08:17,720 --> 00:08:20,600 arising from the complex interplay of quantum fields. 255 00:08:20,600 --> 00:08:23,400 Those are some truly mind-bending ideas. 256 00:08:23,400 --> 00:08:25,920 It's incredible to think that this invisible force 257 00:08:25,920 --> 00:08:29,240 is pushing us to consider such radical concept. 258 00:08:29,240 --> 00:08:30,080 It is. 259 00:08:30,080 --> 00:08:32,920 Dark energy is like a cosmic Rorschach test, 260 00:08:32,920 --> 00:08:35,680 forcing us to confront the limits of our knowledge 261 00:08:35,680 --> 00:08:38,400 and to imagine new possibilities. 262 00:08:38,400 --> 00:08:40,960 So with all these competing theories, 263 00:08:40,960 --> 00:08:42,760 how do scientists go about trying to figure out 264 00:08:42,760 --> 00:08:44,320 which one is right? 265 00:08:44,320 --> 00:08:46,440 How do we study something we can't even see? 266 00:08:46,440 --> 00:08:47,600 That's the challenge, isn't it? 267 00:08:47,600 --> 00:08:50,800 We can't directly detect dark energy in a lab. 268 00:08:50,800 --> 00:08:53,240 But we can observe its effects on the universe. 269 00:08:53,240 --> 00:08:54,880 That's where those powerful telescopes 270 00:08:54,880 --> 00:08:56,000 and observatories come in. 271 00:08:56,000 --> 00:08:58,000 There are eyes on the cosmos, 272 00:08:58,000 --> 00:09:01,160 allowing us to probe the universe's expansion history 273 00:09:01,160 --> 00:09:02,960 and map the distribution of galaxies 274 00:09:02,960 --> 00:09:04,400 with incredible precision. 275 00:09:04,400 --> 00:09:06,000 We talked about the Hubble Space Telescope 276 00:09:06,000 --> 00:09:08,240 in the upcoming Vera Rubin Observatory. 277 00:09:08,240 --> 00:09:09,960 But there are many others, right? 278 00:09:09,960 --> 00:09:10,800 Absolutely. 279 00:09:10,800 --> 00:09:13,080 We have space telescopes like the Euclid Mission 280 00:09:13,080 --> 00:09:15,400 and the Nancy Grace Roman Space Telescope, 281 00:09:15,400 --> 00:09:18,520 both specifically designed to study dark energy. 282 00:09:18,520 --> 00:09:21,920 And here on Earth, we have large ground-based telescopes 283 00:09:21,920 --> 00:09:23,680 like the Very Large Telescope 284 00:09:23,680 --> 00:09:25,800 and the Giant Magellan Telescope, 285 00:09:25,800 --> 00:09:27,720 all contributing to our understanding 286 00:09:27,720 --> 00:09:29,440 of this mysterious force. 287 00:09:29,440 --> 00:09:30,920 So it's a global effort, 288 00:09:30,920 --> 00:09:33,840 a collaboration of scientists from all over the world, 289 00:09:33,840 --> 00:09:36,240 pooling their resources and expertise 290 00:09:36,240 --> 00:09:38,280 to unravel this cosmic mystery. 291 00:09:38,280 --> 00:09:39,120 It is. 292 00:09:39,120 --> 00:09:40,360 And it's not just about observation. 293 00:09:40,360 --> 00:09:42,960 We also have powerful computer simulations 294 00:09:42,960 --> 00:09:45,840 that allow us to model different dark energy scenarios 295 00:09:45,840 --> 00:09:48,800 and see how they affect the evolution of the universe. 296 00:09:48,800 --> 00:09:51,800 It's like running virtual experiments on a cosmic scale. 297 00:09:51,800 --> 00:09:53,520 So by comparing these simulations 298 00:09:53,520 --> 00:09:55,240 with real-world observations, 299 00:09:55,240 --> 00:09:57,520 scientists can start to narrow down the possibilities 300 00:09:57,520 --> 00:09:58,720 and refine their theories. 301 00:09:58,720 --> 00:09:59,680 Exactly. 302 00:09:59,680 --> 00:10:02,680 It's a constant interplay between theory and observation, 303 00:10:02,680 --> 00:10:04,680 a back and forth that pushes us closer 304 00:10:04,680 --> 00:10:07,080 to understanding the true nature of dark energy. 305 00:10:07,080 --> 00:10:09,960 It sounds like we're on the verge of some major breakthroughs. 306 00:10:09,960 --> 00:10:12,280 Are there any specific experiments or projects 307 00:10:12,280 --> 00:10:13,920 that have you particularly excited? 308 00:10:13,920 --> 00:10:16,080 Well, one project that's generating a lot of buzz 309 00:10:16,080 --> 00:10:20,760 is the Dark Energy Spectroscopic Instrument, or DEI. 310 00:10:20,760 --> 00:10:22,320 DEI, you mentioned that earlier. 311 00:10:22,320 --> 00:10:24,800 It's creating a 3D map of the universe, right? 312 00:10:24,800 --> 00:10:25,640 That's right. 313 00:10:25,640 --> 00:10:28,640 DEI is mounted on a telescope in Arizona, 314 00:10:28,640 --> 00:10:30,520 and it's designed to measure the spectra 315 00:10:30,520 --> 00:10:33,840 of millions of galaxies, creating a vast 3D map 316 00:10:33,840 --> 00:10:35,600 that will reveal the universe's structure 317 00:10:35,600 --> 00:10:38,440 and expansion history in unprecedented detail. 318 00:10:38,440 --> 00:10:41,560 It's like creating a Google Earth for the entire universe. 319 00:10:41,560 --> 00:10:43,200 That's a great analogy. 320 00:10:43,200 --> 00:10:45,120 And by analyzing the patterns in this map, 321 00:10:45,120 --> 00:10:46,880 scientists hope to gain new insights 322 00:10:46,880 --> 00:10:48,600 into the nature of dark energy 323 00:10:48,600 --> 00:10:50,920 and its influence on the evolution of the cosmos. 324 00:10:50,920 --> 00:10:53,120 So DEI is like a powerful new tool 325 00:10:53,120 --> 00:10:56,360 that's giving us a much clearer view of the cosmic landscape. 326 00:10:56,360 --> 00:10:59,560 Exactly. It's just one example of the many innovative projects 327 00:10:59,560 --> 00:11:02,320 that are pushing the boundaries of dark energy research. 328 00:11:02,320 --> 00:11:03,960 And with each new discovery, 329 00:11:03,960 --> 00:11:06,760 we're getting closer to understanding this fundamental force 330 00:11:06,760 --> 00:11:08,920 that's shaping the destiny of the universe. 331 00:11:08,920 --> 00:11:11,320 It's truly remarkable to think that we're living in a time 332 00:11:11,320 --> 00:11:14,480 when we can explore such profound mysteries. 333 00:11:14,480 --> 00:11:17,680 But before we get too lost in the vastness of the cosmos, 334 00:11:17,680 --> 00:11:20,720 I think it's important to bring it back down to Earth, so to speak. 335 00:11:20,720 --> 00:11:23,600 Why should our listeners, who may not be physicists or astronomers, 336 00:11:23,600 --> 00:11:25,000 care about dark energy? 337 00:11:25,000 --> 00:11:26,640 That's a great question. 338 00:11:26,640 --> 00:11:29,400 It's easy to get caught up in the scientific details. 339 00:11:29,400 --> 00:11:31,400 But ultimately, dark energy is a reminder 340 00:11:31,400 --> 00:11:34,240 that we live in a universe that is far more strange and wonderful 341 00:11:34,240 --> 00:11:35,240 than we ever imagined. 342 00:11:35,240 --> 00:11:36,880 It's like a cosmic wake-up call, 343 00:11:36,880 --> 00:11:39,960 reminding us that there's so much more to reality than meets the eye. 344 00:11:39,960 --> 00:11:42,280 Precisely. It challenges our assumptions, 345 00:11:42,280 --> 00:11:44,080 expands our imagination, 346 00:11:44,080 --> 00:11:46,560 and inspires us to explore the unknown. 347 00:11:46,560 --> 00:11:49,200 And even if we never fully understand dark energy, 348 00:11:49,200 --> 00:11:52,200 the quest to unravel its mysteries will undoubtedly lead 349 00:11:52,200 --> 00:11:54,240 to new discoveries and technologies 350 00:11:54,240 --> 00:11:56,520 that will benefit humanity in countless ways. 351 00:11:56,520 --> 00:11:58,120 It's like the Apollo program, 352 00:11:58,120 --> 00:12:00,240 which not only landed humans on the Moon, 353 00:12:00,240 --> 00:12:02,720 but also spurred countless technological advancements 354 00:12:02,720 --> 00:12:04,440 that we still benefit from today. 355 00:12:04,440 --> 00:12:07,240 Exactly. The pursuit of knowledge, 356 00:12:07,240 --> 00:12:10,640 especially knowledge about the fundamental nature of the universe, 357 00:12:10,640 --> 00:12:12,160 always has ripple effects. 358 00:12:12,160 --> 00:12:15,000 It expands our horizons and opens up new possibilities 359 00:12:15,000 --> 00:12:16,320 that we can't even foresee. 360 00:12:16,320 --> 00:12:17,960 That's a powerful thought. 361 00:12:17,960 --> 00:12:21,960 So even if we never fully grasp the true nature of dark energy, 362 00:12:21,960 --> 00:12:25,760 the journey of exploration is just as important as the destination. 363 00:12:25,760 --> 00:12:26,840 Absolutely. 364 00:12:26,840 --> 00:12:28,360 The quest to understand dark energy 365 00:12:28,360 --> 00:12:31,240 is a testament to human curiosity, ingenuity, 366 00:12:31,240 --> 00:12:34,120 and our insatiable desire to explore the cosmos. 367 00:12:34,120 --> 00:12:35,120 Well said. 368 00:12:35,120 --> 00:12:37,960 Now, before we delve into the potential fates of the universe, 369 00:12:37,960 --> 00:12:40,280 let's take a moment to consider the broader implications 370 00:12:40,280 --> 00:12:41,960 of what we've learned so far. 371 00:12:41,960 --> 00:12:43,880 What does the existence of dark energy 372 00:12:43,880 --> 00:12:45,840 tell us about our place in the universe? 373 00:12:45,840 --> 00:12:47,200 That's a deep question. 374 00:12:47,200 --> 00:12:49,280 I think, in a way, dark energy is a reminder 375 00:12:49,280 --> 00:12:51,440 of our cosmic insignificance. 376 00:12:51,440 --> 00:12:53,560 It shows us that we are but tiny specks 377 00:12:53,560 --> 00:12:56,000 in a vast and ever-expanding universe, 378 00:12:56,000 --> 00:12:58,600 governed by forces we barely understand. 379 00:12:58,600 --> 00:13:00,080 But at the same time, 380 00:13:00,080 --> 00:13:03,160 it's also a testament to the power of human intellect. 381 00:13:03,160 --> 00:13:05,560 We have the capacity to unravel these mysteries, 382 00:13:05,560 --> 00:13:07,320 to push the boundaries of knowledge, 383 00:13:07,320 --> 00:13:09,360 and to glimpse the true nature of reality. 384 00:13:09,360 --> 00:13:12,120 It's a humbling and inspiring realization all at once. 385 00:13:12,120 --> 00:13:13,880 It is, and it's a reminder 386 00:13:13,880 --> 00:13:16,600 that the journey of discovery is just beginning. 387 00:13:16,600 --> 00:13:19,280 So we've explored the evidence for dark energy, 388 00:13:19,280 --> 00:13:22,360 and we've delved into some of the mind-boggling theories 389 00:13:22,360 --> 00:13:24,280 about what it might be. 390 00:13:24,280 --> 00:13:26,440 We've talked about the cosmological constant 391 00:13:26,440 --> 00:13:28,880 quintessence modified gravity, 392 00:13:28,880 --> 00:13:31,720 and even the possibility of extra dimensions. 393 00:13:31,720 --> 00:13:34,200 It's incredible to think that this invisible force, 394 00:13:34,200 --> 00:13:36,880 which we only discovered a few decades ago, 395 00:13:36,880 --> 00:13:38,480 has the potential to rewrite 396 00:13:38,480 --> 00:13:40,160 our understanding of the universe. 397 00:13:40,160 --> 00:13:42,280 It really highlights how much we still don't know 398 00:13:42,280 --> 00:13:43,120 about the cosmos. 399 00:13:43,120 --> 00:13:44,200 Exactly. 400 00:13:44,200 --> 00:13:46,320 It's like we've stumbled upon a whole new continent 401 00:13:46,320 --> 00:13:47,800 on the map of physics, 402 00:13:47,800 --> 00:13:49,360 and we're just beginning to explore 403 00:13:49,360 --> 00:13:50,760 its uncharted territories. 404 00:13:50,760 --> 00:13:52,760 And who knows what wonders and mysteries 405 00:13:52,760 --> 00:13:54,800 we'll uncover along the way. 406 00:13:54,800 --> 00:13:56,080 Speaking of mysteries, 407 00:13:56,080 --> 00:13:58,240 we've touched upon the implications of dark energy 408 00:13:58,240 --> 00:13:59,600 for the fate of the universe. 409 00:13:59,600 --> 00:14:00,440 Right. 410 00:14:00,440 --> 00:14:03,320 We've discussed scenarios like the Big Freeze, 411 00:14:03,320 --> 00:14:05,720 where the universe keeps expanding forever, 412 00:14:05,720 --> 00:14:07,960 eventually becoming cold and desolate. 413 00:14:07,960 --> 00:14:09,240 And then there's the Big Rip, 414 00:14:09,240 --> 00:14:11,000 where dark energy gets so powerful 415 00:14:11,000 --> 00:14:12,800 that it rips apart everything, 416 00:14:12,800 --> 00:14:14,680 from galaxies to atoms. 417 00:14:14,680 --> 00:14:17,080 It's a pretty dramatic ending, to say the least. 418 00:14:17,080 --> 00:14:19,640 It makes you wonder if there's a cosmic drama unfolding 419 00:14:19,640 --> 00:14:21,800 on a scale we can barely comprehend. 420 00:14:21,800 --> 00:14:22,800 There is. 421 00:14:22,800 --> 00:14:26,280 And dark energy is one of the key players in that drama. 422 00:14:26,280 --> 00:14:30,120 So if dark energy is driving the universe's expansion, 423 00:14:30,120 --> 00:14:32,800 what does that mean for the future of everything? 424 00:14:32,800 --> 00:14:35,840 What's the most likely scenario based on what we know now? 425 00:14:35,840 --> 00:14:38,720 Well, if dark energy continues to behave 426 00:14:38,720 --> 00:14:40,480 as we observe it today, 427 00:14:40,480 --> 00:14:43,200 the most likely scenario is the Big Freeze. 428 00:14:43,200 --> 00:14:44,840 The Big Freeze? 429 00:14:44,840 --> 00:14:46,400 Paint a picture for our listeners. 430 00:14:46,400 --> 00:14:47,320 What would that look like? 431 00:14:47,320 --> 00:14:49,120 Imagine a universe where galaxies 432 00:14:49,120 --> 00:14:51,240 are constantly moving farther apart. 433 00:14:51,240 --> 00:14:52,560 The space between them stretching 434 00:14:52,560 --> 00:14:54,000 like an endless rubber sheet. 435 00:14:54,000 --> 00:14:56,600 Over billions of years, stars will burn out, 436 00:14:56,600 --> 00:14:58,160 galaxies will drift apart, 437 00:14:58,160 --> 00:15:00,800 and the universe will become increasingly cold and empty. 438 00:15:00,800 --> 00:15:02,760 A cosmic ghost town, 439 00:15:02,760 --> 00:15:04,760 with the remnants of stars and galaxies 440 00:15:04,760 --> 00:15:06,840 scattered across an immense void. 441 00:15:06,840 --> 00:15:08,840 It's a rather bleak picture, 442 00:15:08,840 --> 00:15:10,680 but it's the most plausible scenario 443 00:15:10,680 --> 00:15:13,240 based on our current understanding of dark energy. 444 00:15:13,240 --> 00:15:15,560 Is there any chance that things could go differently? 445 00:15:15,560 --> 00:15:17,400 Could dark energy change its behavior 446 00:15:17,400 --> 00:15:18,800 leading to a different fate? 447 00:15:18,800 --> 00:15:19,760 It's possible. 448 00:15:19,760 --> 00:15:21,680 One of the big questions is whether dark energy 449 00:15:21,680 --> 00:15:25,040 is truly constant or if it can evolve over time. 450 00:15:25,040 --> 00:15:27,400 So we're not even sure if this invisible force 451 00:15:27,400 --> 00:15:29,800 is a steady hand or a wild card. 452 00:15:29,800 --> 00:15:30,760 Exactly. 453 00:15:30,760 --> 00:15:33,160 If dark energy is dynamic, 454 00:15:33,160 --> 00:15:35,280 if its strength can change, 455 00:15:35,280 --> 00:15:38,200 then the fate of the universe becomes much more uncertain. 456 00:15:38,200 --> 00:15:40,880 It's like realizing that the script of the cosmic drama 457 00:15:40,880 --> 00:15:41,880 is still being written. 458 00:15:41,880 --> 00:15:43,600 That's a great way to put it. 459 00:15:43,600 --> 00:15:45,480 And that's why scientists are so eager 460 00:15:45,480 --> 00:15:47,960 to study dark energy in more detail. 461 00:15:47,960 --> 00:15:50,920 The more we learn about its properties and behavior, 462 00:15:50,920 --> 00:15:52,280 the better we'll be able to predict 463 00:15:52,280 --> 00:15:54,640 the universe's ultimate destiny. 464 00:15:54,640 --> 00:15:56,960 It's fascinating to think that the fate of everything 465 00:15:56,960 --> 00:15:59,840 could hinge on the whims of this invisible force. 466 00:15:59,840 --> 00:16:00,680 It is. 467 00:16:00,680 --> 00:16:02,680 And it's a reminder that we are part of a universe 468 00:16:02,680 --> 00:16:06,000 that is far more complex and dynamic than we ever imagined. 469 00:16:06,000 --> 00:16:09,320 So as we wrap up our deep dive into dark energy, 470 00:16:09,320 --> 00:16:10,840 what are some of the key takeaways 471 00:16:10,840 --> 00:16:12,320 you'd like our listeners to remember? 472 00:16:12,320 --> 00:16:13,480 Well, first and foremost, 473 00:16:13,480 --> 00:16:15,960 I hope they come away with a sense of awe and wonder 474 00:16:15,960 --> 00:16:19,000 at the sheer scale and mystery of the universe. 475 00:16:19,000 --> 00:16:20,560 It's hard not to feel a sense of awe 476 00:16:20,560 --> 00:16:22,800 when you contemplate the vastness of space 477 00:16:22,800 --> 00:16:24,120 and the forces that shape it. 478 00:16:24,120 --> 00:16:24,960 Exactly. 479 00:16:24,960 --> 00:16:26,960 And second, I hope they appreciate 480 00:16:26,960 --> 00:16:30,280 the incredible ingenuity and dedication of the scientists 481 00:16:30,280 --> 00:16:33,920 who are working tirelessly to unravel these cosmic mysteries. 482 00:16:33,920 --> 00:16:36,840 It's a testament to the power of human curiosity 483 00:16:36,840 --> 00:16:39,160 and our desire to understand the world around us. 484 00:16:39,160 --> 00:16:40,320 Absolutely. 485 00:16:40,320 --> 00:16:41,600 And finally, I hope they take away 486 00:16:41,600 --> 00:16:43,480 a sense of hope and optimism. 487 00:16:43,480 --> 00:16:44,840 Hope and optimism. 488 00:16:44,840 --> 00:16:47,480 In the face of a universe that's expanding forever 489 00:16:47,480 --> 00:16:49,680 and might eventually end in the big freeze. 490 00:16:49,680 --> 00:16:50,800 Yes. 491 00:16:50,800 --> 00:16:53,760 Because even though the universe might be vast and indifferent, 492 00:16:53,760 --> 00:16:54,840 we are not. 493 00:16:54,840 --> 00:16:59,080 We have the capacity to explore, to discover, to learn, 494 00:16:59,080 --> 00:17:00,040 and to create. 495 00:17:00,040 --> 00:17:02,000 It's a reminder that even in a universe 496 00:17:02,000 --> 00:17:04,760 governed by seemingly impersonal forces, 497 00:17:04,760 --> 00:17:08,440 there's still room for wonder, meaning, and purpose. 498 00:17:08,440 --> 00:17:09,840 Beautifully said. 499 00:17:09,840 --> 00:17:10,680 Well, on that note, 500 00:17:10,680 --> 00:17:12,920 I think it's time to wrap up our cosmic adventure. 501 00:17:12,920 --> 00:17:15,200 Thanks for joining us on this journey into the mysteries 502 00:17:15,200 --> 00:17:16,040 of dark energy. 503 00:17:16,040 --> 00:17:16,960 It's been my pleasure. 504 00:17:16,960 --> 00:17:19,360 And to our listeners, we encourage you to continue 505 00:17:19,360 --> 00:17:21,240 exploring the wonders of the universe. 506 00:17:21,240 --> 00:17:23,400 Keep asking questions, keep learning, 507 00:17:23,400 --> 00:17:25,040 and never lose your sense of awe. 508 00:17:25,040 --> 00:17:27,720 And don't forget to follow and subscribe to Cosmos in a Pod 509 00:17:27,720 --> 00:17:30,080 for more explorations of space and astronomy. 510 00:17:30,080 --> 00:17:31,920 Be sure to check out our YouTube channel 511 00:17:31,920 --> 00:17:33,840 for even more cosmic content. 512 00:17:33,840 --> 00:17:43,840 Until next time, keep looking up.