1 00:00:08,520 --> 00:00:11,000 Speaker 1: Hey, Jorgey, do you ever get the feeling that this 2 00:00:11,039 --> 00:00:14,760 Speaker 1: has all happened before? Well, this is our two and 3 00:00:14,800 --> 00:00:18,919 Speaker 1: fifty episode, so yeah, there's a sense of deja vu. Yeah, 4 00:00:18,960 --> 00:00:21,080 Speaker 1: but think a little bigger than that, like you know 5 00:00:21,160 --> 00:00:24,440 Speaker 1: about the whole universe? You mean, like, has there been 6 00:00:24,480 --> 00:00:28,080 Speaker 1: another universe before this one? Yeah? Or is our universe 7 00:00:28,280 --> 00:00:31,560 Speaker 1: the first one? I hope we're the first ones that 8 00:00:31,560 --> 00:00:33,559 Speaker 1: would be special. I don't know. I'd like us to 9 00:00:33,600 --> 00:00:35,800 Speaker 1: not be the first, so the universe has had a 10 00:00:35,880 --> 00:00:38,880 Speaker 1: chance to like iron out some of the kinks. You 11 00:00:38,880 --> 00:00:42,400 Speaker 1: don't want to be in season one of the universe, No, 12 00:00:42,600 --> 00:00:45,040 Speaker 1: it always takes a few seasons to figure it out. 13 00:00:45,159 --> 00:00:49,720 Speaker 1: You want to be this season finale or the series finale? Well, 14 00:00:49,800 --> 00:00:51,760 Speaker 1: you know, it's tricky because sequels are you know, hit 15 00:00:51,840 --> 00:01:09,160 Speaker 1: or miss? Hi am or Hey, I'm a cartoonist and 16 00:01:09,200 --> 00:01:12,400 Speaker 1: the creator of PhD comics. Hi, I'm Daniel. I'm a 17 00:01:12,440 --> 00:01:16,480 Speaker 1: particle physicist, and I'm the first generation physicist in my family. 18 00:01:16,640 --> 00:01:20,320 Speaker 1: Oh really, hopefully the last or maybe the last. How 19 00:01:20,360 --> 00:01:22,440 Speaker 1: are you kids feeling about the whole thing? Yeah? I 20 00:01:22,440 --> 00:01:24,479 Speaker 1: think I might be the physics finale in this family. 21 00:01:25,640 --> 00:01:29,360 Speaker 1: I am definitely a first generation cartoonists from Panama. Well, 22 00:01:29,400 --> 00:01:30,959 Speaker 1: there you go. You don't have to do what your 23 00:01:30,959 --> 00:01:33,360 Speaker 1: parents have done. Well, actually, my parents are pretty good 24 00:01:33,440 --> 00:01:36,600 Speaker 1: artists as well, even though they're also engineers. Awesome, but 25 00:01:36,680 --> 00:01:39,280 Speaker 1: welcome to our podcast Daniel and Jorge Explain the Universe, 26 00:01:39,360 --> 00:01:41,720 Speaker 1: a production of I Heart Radio in which we take 27 00:01:41,760 --> 00:01:44,360 Speaker 1: you on a tour of all the amazing questions about 28 00:01:44,360 --> 00:01:47,160 Speaker 1: our universe, how we will end, how it began, how 29 00:01:47,200 --> 00:01:49,440 Speaker 1: it works right here daying in the middle of it, 30 00:01:49,560 --> 00:01:51,760 Speaker 1: and on our tour of the universe, we stop and 31 00:01:51,800 --> 00:01:54,360 Speaker 1: talk about how it works, why it works, and what 32 00:01:54,440 --> 00:01:58,240 Speaker 1: we don't understand, hopefully leaving you with some understanding of 33 00:01:58,240 --> 00:02:00,840 Speaker 1: your own. Yeah, because there is a to understand in 34 00:02:00,880 --> 00:02:05,840 Speaker 1: this universe. It's big and complex and old and possibly infinite, 35 00:02:06,200 --> 00:02:09,560 Speaker 1: and it may not stop there with the universe, I mean, yeah, exactly. 36 00:02:09,600 --> 00:02:12,760 Speaker 1: We have questions about how far the universe goes on, 37 00:02:12,960 --> 00:02:15,440 Speaker 1: Does it wrap around on itself? Does it go on forever? 38 00:02:15,760 --> 00:02:18,560 Speaker 1: And we have questions about how long the universe will 39 00:02:18,600 --> 00:02:21,680 Speaker 1: continue and where it came from, was there a beginning 40 00:02:21,720 --> 00:02:25,440 Speaker 1: at all? Or does the universe extend back forever in time? Yeah, 41 00:02:25,520 --> 00:02:28,080 Speaker 1: because we think of the universe as everything there isn't, 42 00:02:28,160 --> 00:02:31,160 Speaker 1: ever has been, and ever will be. But there are 43 00:02:31,240 --> 00:02:33,519 Speaker 1: a lot of theories in physics that maybe does. It 44 00:02:33,600 --> 00:02:36,560 Speaker 1: is not the only universe, you know. There's ideas about 45 00:02:36,680 --> 00:02:40,720 Speaker 1: parallel universes and multi universe, and there's also ideas about 46 00:02:40,960 --> 00:02:43,480 Speaker 1: other universe that may come to be or that have 47 00:02:43,680 --> 00:02:46,240 Speaker 1: been before. That's right. If you are used to the 48 00:02:46,280 --> 00:02:49,040 Speaker 1: feeling that the universe has dwarfed us, that we are 49 00:02:49,080 --> 00:02:53,400 Speaker 1: finding ourselves to be a tiny cosmic spec on a vast, vast, 50 00:02:53,560 --> 00:02:56,880 Speaker 1: unimaginable huge scale, then get ready to blow your mind 51 00:02:56,919 --> 00:02:59,600 Speaker 1: at an even deeper level, because it turns out our 52 00:02:59,680 --> 00:03:02,840 Speaker 1: universe may not even be everything. It may only be 53 00:03:03,000 --> 00:03:07,000 Speaker 1: one of many universes. Yeah. This actually blows my daughter's 54 00:03:07,040 --> 00:03:09,560 Speaker 1: mind a lot. She's like, how can there be multiple universes? 55 00:03:09,639 --> 00:03:13,119 Speaker 1: Isn't the universe all that there is? And I think 56 00:03:13,120 --> 00:03:16,320 Speaker 1: she's again, you know, carrying on my tradition of complaining 57 00:03:16,360 --> 00:03:19,560 Speaker 1: about naming things in physics. There you go, she's a 58 00:03:19,600 --> 00:03:23,560 Speaker 1: second generation name complainer. Yeah, physics name complainer. I'm so proud. 59 00:03:24,400 --> 00:03:26,400 Speaker 1: But it's a good point because often we define the 60 00:03:26,480 --> 00:03:29,320 Speaker 1: universe to be like everything as we know it at 61 00:03:29,360 --> 00:03:31,960 Speaker 1: that moment, and then when we realize, oh, there's more, 62 00:03:32,440 --> 00:03:34,920 Speaker 1: we don't just redefine the universe to also include that, 63 00:03:34,960 --> 00:03:38,040 Speaker 1: we're like, oh, let's call that another universe, and so 64 00:03:38,120 --> 00:03:40,880 Speaker 1: it does get pretty awkward. Yeah, well, maybe universe is 65 00:03:40,920 --> 00:03:43,640 Speaker 1: more like everything we could potentially reach at the moment, 66 00:03:43,720 --> 00:03:46,360 Speaker 1: you know, like everything that exists with us. Yeah, well 67 00:03:46,360 --> 00:03:49,200 Speaker 1: that's sort of like the observable universe is like everything 68 00:03:49,240 --> 00:03:51,880 Speaker 1: that can influence us, everything that we can interact with 69 00:03:51,960 --> 00:03:55,040 Speaker 1: because it has had time to send us light. So 70 00:03:55,120 --> 00:03:57,880 Speaker 1: that's definitely one fair definition of the universe. But you 71 00:03:57,880 --> 00:04:00,400 Speaker 1: could also imagine, hey, this stuff going on out there 72 00:04:00,440 --> 00:04:03,480 Speaker 1: that's not like within a sphere centered around my head, 73 00:04:03,480 --> 00:04:06,600 Speaker 1: shouldn't you also include that in the universe. And then 74 00:04:06,640 --> 00:04:09,000 Speaker 1: you can imagine forwards and time and backwards and time, 75 00:04:09,040 --> 00:04:10,800 Speaker 1: and you know, it's nice to have a definition of 76 00:04:10,800 --> 00:04:13,360 Speaker 1: the universe that doesn't center a human because it doesn't 77 00:04:13,360 --> 00:04:15,880 Speaker 1: feel like we are sort of essentially important to the universe, 78 00:04:16,120 --> 00:04:18,479 Speaker 1: right Well, I like being the center of my universe, 79 00:04:20,640 --> 00:04:23,440 Speaker 1: and our our listeners are the center of our universe. 80 00:04:23,480 --> 00:04:27,719 Speaker 1: For sure, They're definitely important. Yeah, everyone special. There's this 81 00:04:27,800 --> 00:04:30,000 Speaker 1: question of where the universe came from and what's going 82 00:04:30,040 --> 00:04:32,279 Speaker 1: to happen to it? And I think more important is 83 00:04:32,320 --> 00:04:35,680 Speaker 1: that question about where the universe came from, Like how 84 00:04:35,720 --> 00:04:39,479 Speaker 1: can so much stuff just come out of nothing? Yeah? 85 00:04:39,560 --> 00:04:42,560 Speaker 1: And it's a really fun exploration because you look at 86 00:04:42,600 --> 00:04:44,440 Speaker 1: the way the universe is now you say, where did 87 00:04:44,440 --> 00:04:46,839 Speaker 1: this come from? And Okay, cool, we understand how the 88 00:04:46,880 --> 00:04:49,440 Speaker 1: solar system formed, Well where did that stuff that made 89 00:04:49,440 --> 00:04:51,919 Speaker 1: the Solar system come from? And it's this cycle of 90 00:04:51,920 --> 00:04:54,680 Speaker 1: stepping backwards and further and further into the depths of 91 00:04:54,720 --> 00:04:57,400 Speaker 1: time and wondering like how far can we go to 92 00:04:57,600 --> 00:05:00,920 Speaker 1: understand the origin of everything? And is there a final 93 00:05:00,960 --> 00:05:04,560 Speaker 1: answer or could you go forever? Right? Yeah, because we're 94 00:05:04,560 --> 00:05:07,200 Speaker 1: not used to this idea of something coming from nothing, right, 95 00:05:07,320 --> 00:05:09,359 Speaker 1: I mean, it would be weird if the universe suddenly 96 00:05:09,360 --> 00:05:12,440 Speaker 1: appeared out of nothingness. Yeah, well, it would be weird 97 00:05:12,520 --> 00:05:15,600 Speaker 1: if the universe wasn't weird. Right. Basically, everything we've learned 98 00:05:15,640 --> 00:05:18,120 Speaker 1: about the universe shocked and surprised us. So if we 99 00:05:18,200 --> 00:05:19,880 Speaker 1: found an answer and just went like, oh, yeah, that 100 00:05:19,960 --> 00:05:22,320 Speaker 1: kind of makes sense, that would be kind of surprising. 101 00:05:23,279 --> 00:05:25,120 Speaker 1: All right. So at some point the universe that have 102 00:05:25,160 --> 00:05:28,520 Speaker 1: came into existence was created in the Big Bang. But 103 00:05:28,600 --> 00:05:30,480 Speaker 1: I guess the big question is kind of what happened 104 00:05:30,480 --> 00:05:32,640 Speaker 1: before the Big Bang and where did the universe come from? 105 00:05:32,760 --> 00:05:34,320 Speaker 1: And so there are a lot of theories out there 106 00:05:34,360 --> 00:05:37,479 Speaker 1: about what could have happened or what happened, but none 107 00:05:37,480 --> 00:05:39,719 Speaker 1: of them are nailed down, right, That's right. There's still 108 00:05:39,760 --> 00:05:42,679 Speaker 1: a lot of speculation. We don't really know what happened 109 00:05:42,680 --> 00:05:45,440 Speaker 1: before the Big Bang, and we might not ever know, 110 00:05:45,680 --> 00:05:48,280 Speaker 1: and so there's a huge variety of theories out there 111 00:05:48,279 --> 00:05:50,719 Speaker 1: that explained what could have happened. Maybe there was nothing, 112 00:05:51,000 --> 00:05:53,440 Speaker 1: maybe there was a big crunch that proceeded the Big Bang. 113 00:05:53,640 --> 00:05:56,080 Speaker 1: But today I wanted to talk about one really specially 114 00:05:56,160 --> 00:05:59,880 Speaker 1: interesting theory. They gained popularity recently because it's proponent one 115 00:06:00,080 --> 00:06:03,440 Speaker 1: Nobel Prize last year. M. Yeah, this is a theory 116 00:06:03,520 --> 00:06:06,640 Speaker 1: that talks about the universe is a big cycle, right, 117 00:06:06,720 --> 00:06:10,680 Speaker 1: like maybe there were other universes before our universe. Yeah, exactly. 118 00:06:10,800 --> 00:06:13,280 Speaker 1: This theory sees the universe is big cycles, but not 119 00:06:13,360 --> 00:06:16,240 Speaker 1: the kind you're probably familiar with. You've probably heard of 120 00:06:16,279 --> 00:06:18,680 Speaker 1: the theory that the universe goes through a cycle of 121 00:06:18,760 --> 00:06:21,880 Speaker 1: bangs and then crunches and bangs and then crunches This 122 00:06:21,920 --> 00:06:25,360 Speaker 1: is a totally different idea that has a sickly cosmology 123 00:06:25,400 --> 00:06:28,120 Speaker 1: at its heart. All right, So today on the podcast, 124 00:06:28,120 --> 00:06:36,440 Speaker 1: we'll be asking the question, what is the conformal cyclic 125 00:06:36,560 --> 00:06:40,320 Speaker 1: cosmology theory? All right? This is not the usual big 126 00:06:40,360 --> 00:06:44,000 Speaker 1: bank to big crunch universe theory. You're saying. It's different. 127 00:06:44,160 --> 00:06:46,880 Speaker 1: It's different. It goes for the cycle approach. It says, 128 00:06:47,120 --> 00:06:50,400 Speaker 1: you know, let's sweep away this question of whether there 129 00:06:50,520 --> 00:06:52,800 Speaker 1: was the beginning by saying there was never beginning. There's 130 00:06:52,800 --> 00:06:56,760 Speaker 1: an infinite number of cycles. But it doesn't link up 131 00:06:56,760 --> 00:06:59,920 Speaker 1: big crunches to big bangs. It's a totally different idea, 132 00:07:00,279 --> 00:07:04,600 Speaker 1: a little bit more bonkers and super fascinating because it 133 00:07:04,680 --> 00:07:07,680 Speaker 1: suggests that you might be able to see an imprint 134 00:07:07,720 --> 00:07:12,280 Speaker 1: of the previous universe, somehow left on our universe. Well, 135 00:07:12,360 --> 00:07:15,600 Speaker 1: let's maybe catch up our listeners, because the idea they 136 00:07:15,680 --> 00:07:17,880 Speaker 1: might have heard about is that the universe, you know, 137 00:07:18,040 --> 00:07:20,000 Speaker 1: came out of a big bang, out of a really 138 00:07:20,040 --> 00:07:24,240 Speaker 1: small space. Then it was huge. It exploded basically in 139 00:07:24,320 --> 00:07:27,080 Speaker 1: the big bang, and then after you know, maybe trillions 140 00:07:27,080 --> 00:07:30,040 Speaker 1: of years, it collapses back down into a big crunch, 141 00:07:30,240 --> 00:07:33,840 Speaker 1: which then triggers another big bang. For another universe, kind 142 00:07:33,840 --> 00:07:36,800 Speaker 1: of like Season two or a sequel to the Universe, 143 00:07:37,280 --> 00:07:40,640 Speaker 1: and then that universe explodes and expands, and after trillions 144 00:07:40,640 --> 00:07:43,880 Speaker 1: of years it crunches back down again, and so on 145 00:07:43,960 --> 00:07:47,400 Speaker 1: and so on at infinitum. Right, and so that's the 146 00:07:47,400 --> 00:07:49,800 Speaker 1: basic idea that people usually talk about when they talk 147 00:07:49,800 --> 00:07:53,120 Speaker 1: about cycles of the universe. Yeah, exactly. So that's the 148 00:07:53,160 --> 00:07:56,400 Speaker 1: typical idea. But today we're going to explore a different one. Yeah. So, 149 00:07:56,480 --> 00:07:58,920 Speaker 1: as usual, Daniel went out there to ask people on 150 00:07:58,920 --> 00:08:01,760 Speaker 1: the internet if they heard of this new theory about 151 00:08:01,880 --> 00:08:04,920 Speaker 1: universe cycles. That's right, So thank you to everybody who 152 00:08:05,040 --> 00:08:08,360 Speaker 1: shared your speculation. And if you are willing to answer 153 00:08:08,520 --> 00:08:11,400 Speaker 1: random questions from me online for us to use on 154 00:08:11,400 --> 00:08:14,640 Speaker 1: the podcast, please write to us two questions at Daniel 155 00:08:14,640 --> 00:08:17,239 Speaker 1: and Jorge dot com. So think about it for a second. 156 00:08:17,320 --> 00:08:20,520 Speaker 1: Have you heard of any theories about the universe cycling 157 00:08:20,640 --> 00:08:24,800 Speaker 1: over and over again? Here's what people had to say. Okay, 158 00:08:25,120 --> 00:08:28,920 Speaker 1: you are clearly just taking birds together now, but I 159 00:08:29,000 --> 00:08:32,520 Speaker 1: will try to give you a guess. Anyway, cycled cosmos 160 00:08:32,520 --> 00:08:35,280 Speaker 1: could mean it is something about the form of all universe, 161 00:08:35,760 --> 00:08:40,920 Speaker 1: So instead of being infinite, it could be somehow bent 162 00:08:41,080 --> 00:08:43,640 Speaker 1: in itself, so you wouldn't never reach an edge but 163 00:08:43,920 --> 00:08:47,640 Speaker 1: just start over. Or it could be about its growth 164 00:08:47,720 --> 00:08:51,200 Speaker 1: and its development, like there could be a big crunch 165 00:08:51,240 --> 00:08:54,240 Speaker 1: at the end of the life cycle followed by another 166 00:08:54,240 --> 00:08:57,640 Speaker 1: big bang and so on. This makes me think of 167 00:08:57,760 --> 00:09:01,360 Speaker 1: the theory that I've heard that the universe keeps being 168 00:09:01,400 --> 00:09:04,240 Speaker 1: created over and over again, so it grows and grows 169 00:09:04,240 --> 00:09:07,480 Speaker 1: and grows and then becomes a black hole, and then 170 00:09:08,120 --> 00:09:11,360 Speaker 1: the black hole creates its own universe in a sort 171 00:09:11,400 --> 00:09:14,439 Speaker 1: of big bang like event. And so that's what makes 172 00:09:14,480 --> 00:09:16,920 Speaker 1: me think of And since the word conformal is in there, 173 00:09:17,280 --> 00:09:20,360 Speaker 1: I'm guessing maybe every universe is the same over and 174 00:09:20,400 --> 00:09:22,960 Speaker 1: over again. I think it has something to do with 175 00:09:23,760 --> 00:09:28,280 Speaker 1: the cycles that we see in the cosmos, like the 176 00:09:28,280 --> 00:09:31,600 Speaker 1: births and the deaths of stars and galaxies. I'm not sure, 177 00:09:31,720 --> 00:09:34,800 Speaker 1: but I think it might have to do with like 178 00:09:35,640 --> 00:09:40,480 Speaker 1: the universe cycling between a big bang and a big crunch. 179 00:09:40,840 --> 00:09:43,120 Speaker 1: All Right, it sounds like people have heard about this 180 00:09:43,320 --> 00:09:50,600 Speaker 1: general idea of crunches and bangs, bangs, bangs bang guy bangs. Yeah, 181 00:09:50,760 --> 00:09:53,720 Speaker 1: And one of the answers seems to be following in 182 00:09:53,800 --> 00:09:56,680 Speaker 1: your tradition of complaining about the name, you're just sticking 183 00:09:56,800 --> 00:10:03,840 Speaker 1: words together. It's fair both English professors and professors are 184 00:10:03,880 --> 00:10:06,800 Speaker 1: guilty of that. But yeah, so, I guess let's talk 185 00:10:06,840 --> 00:10:10,839 Speaker 1: about this idea of inflation in the early universe. I mean, 186 00:10:11,120 --> 00:10:13,920 Speaker 1: where did this idea that there could be a cycle 187 00:10:13,960 --> 00:10:16,920 Speaker 1: to the universe come from? And we thought of it first. Yeah, 188 00:10:16,960 --> 00:10:19,600 Speaker 1: the origins of it come from the realization in the 189 00:10:19,679 --> 00:10:23,200 Speaker 1: last few decades that the universe might have had some 190 00:10:23,280 --> 00:10:25,760 Speaker 1: sort of starting point. Remember, like a hundred or so 191 00:10:25,880 --> 00:10:28,080 Speaker 1: years ago, people looked at its stars and they didn't 192 00:10:28,080 --> 00:10:30,640 Speaker 1: see the stars moving by eye, and they figured, hey, 193 00:10:30,679 --> 00:10:32,800 Speaker 1: I guess the universe is just statics, just like a 194 00:10:32,840 --> 00:10:34,920 Speaker 1: bunch of stars hanging out in space. And it was 195 00:10:35,000 --> 00:10:37,320 Speaker 1: very natural for people to think that it could have 196 00:10:37,360 --> 00:10:40,240 Speaker 1: always been that way. It looks pretty old, after all, 197 00:10:40,320 --> 00:10:43,040 Speaker 1: and so why not imagine it lasted forever. But then 198 00:10:43,080 --> 00:10:46,800 Speaker 1: when Hubble discovered the universe was expanding, that sort of 199 00:10:46,880 --> 00:10:50,079 Speaker 1: changed the story. It suggested that the universe is changing 200 00:10:50,280 --> 00:10:52,920 Speaker 1: and couldn't always have looked the way it does. And 201 00:10:52,960 --> 00:10:55,920 Speaker 1: then when you extrapolate backwards in time and you think, well, 202 00:10:56,120 --> 00:10:59,160 Speaker 1: if it's expanding now, then it should have been contracting 203 00:10:59,280 --> 00:11:01,720 Speaker 1: as we go back in time. That takes you back 204 00:11:01,760 --> 00:11:04,680 Speaker 1: to something that feels sort of like a beginning, a 205 00:11:04,760 --> 00:11:07,880 Speaker 1: point when the universe is much much more dense, yeah, 206 00:11:08,040 --> 00:11:11,160 Speaker 1: much more raw, right, like the whole entire universe, every 207 00:11:11,160 --> 00:11:13,560 Speaker 1: star in galaxy you ever seen, was in a really 208 00:11:13,679 --> 00:11:17,679 Speaker 1: small space about fourteen billion years ago, and everything was 209 00:11:17,720 --> 00:11:20,760 Speaker 1: just like a state of plasma, right, like just raw energy. 210 00:11:20,880 --> 00:11:23,840 Speaker 1: That's right. When the universe was much younger, it was hotter, 211 00:11:23,920 --> 00:11:27,160 Speaker 1: and it was denser, and so things work differently, you know, 212 00:11:27,240 --> 00:11:29,559 Speaker 1: just like there are different phases of matter that you're 213 00:11:29,559 --> 00:11:33,000 Speaker 1: familiar with water, you can be ice or liquid or gas. 214 00:11:33,200 --> 00:11:36,360 Speaker 1: The universe itself sort of has phases, and when stuff 215 00:11:36,400 --> 00:11:39,480 Speaker 1: is much much denser, there are different rules of physics 216 00:11:39,520 --> 00:11:42,040 Speaker 1: that emerge, and so like the laws of physics, they 217 00:11:42,040 --> 00:11:43,880 Speaker 1: don't violate the ones we have now, but they sort 218 00:11:43,880 --> 00:11:47,640 Speaker 1: of operate under different regimes. Different laws emerge, and so 219 00:11:47,720 --> 00:11:50,120 Speaker 1: it was very different from the way we imagine it now, 220 00:11:50,360 --> 00:11:53,360 Speaker 1: and we have some direct evidence that that actually existed. 221 00:11:53,400 --> 00:11:56,800 Speaker 1: This isn't just a calculation in people's minds. We've seen 222 00:11:57,000 --> 00:12:00,800 Speaker 1: light from that early universe plasma or diving at Earth. 223 00:12:00,800 --> 00:12:04,040 Speaker 1: It's called the cosmic microwave background radiation and it's sort 224 00:12:04,080 --> 00:12:06,680 Speaker 1: of like the last glow from the Big Bang. Yeah, 225 00:12:06,679 --> 00:12:08,520 Speaker 1: so we can see light that kind of escaped that 226 00:12:08,600 --> 00:12:13,240 Speaker 1: plasma right before and basically evaporated, right, yeah, exactly, and 227 00:12:13,320 --> 00:12:16,520 Speaker 1: that plasma sort of faded out and cooled off and 228 00:12:16,600 --> 00:12:18,920 Speaker 1: turned into neutral atoms, and then we can see that 229 00:12:19,000 --> 00:12:21,640 Speaker 1: light because it's still banging around the universe. The universe 230 00:12:21,679 --> 00:12:24,520 Speaker 1: sort of became transparent at that moment. So that was 231 00:12:24,559 --> 00:12:27,400 Speaker 1: like a really exciting piece of evidence when people saw 232 00:12:27,440 --> 00:12:31,240 Speaker 1: the microwave background radiations is several decades ago, really confirming 233 00:12:31,520 --> 00:12:34,320 Speaker 1: that that thing actually happened, That the universe once was 234 00:12:34,400 --> 00:12:37,520 Speaker 1: a big hot plasma, and that's very different from the 235 00:12:37,520 --> 00:12:39,840 Speaker 1: way it is today. Right, Well, it was a hot 236 00:12:39,880 --> 00:12:41,719 Speaker 1: mass back then, and it seems like it's a hot 237 00:12:41,720 --> 00:12:46,120 Speaker 1: mass right now. We're constantly on the edge of catastrophe. 238 00:12:46,760 --> 00:12:48,800 Speaker 1: But there are a lot of things we don't understand, 239 00:12:48,840 --> 00:12:51,400 Speaker 1: like what happened before that Big Bang with that big 240 00:12:51,440 --> 00:12:54,160 Speaker 1: hot ball of plasma. Yeah, that hot ball plasma is 241 00:12:54,160 --> 00:12:57,439 Speaker 1: an exciting threshold reach. We're looking back fourteen billion years 242 00:12:57,440 --> 00:12:59,240 Speaker 1: into the history of the universe. But you know, we 243 00:12:59,320 --> 00:13:01,240 Speaker 1: want to probe, but we want to know where that 244 00:13:01,400 --> 00:13:04,480 Speaker 1: ball of plasma came from, what explains how that got 245 00:13:04,520 --> 00:13:06,120 Speaker 1: there and what made that? You know, we want to 246 00:13:06,240 --> 00:13:09,640 Speaker 1: keep stepping this ladder backwards in time to understand really 247 00:13:09,679 --> 00:13:11,560 Speaker 1: what was going on, and the way to do that 248 00:13:11,679 --> 00:13:13,840 Speaker 1: is to ask more questions, to say, like, do we 249 00:13:14,000 --> 00:13:16,440 Speaker 1: understand the way that ball of plasma look? Can we 250 00:13:16,480 --> 00:13:19,000 Speaker 1: explain it? Do we understand, for example, all of the 251 00:13:19,080 --> 00:13:21,440 Speaker 1: ripples in it? Because the light we see from that 252 00:13:21,480 --> 00:13:24,240 Speaker 1: ball of plasma is not all the same temperature. There's 253 00:13:24,240 --> 00:13:27,800 Speaker 1: some variations up and down in that light. Yeah, And 254 00:13:27,840 --> 00:13:31,040 Speaker 1: so our prevailing theory about what happened during those first 255 00:13:31,040 --> 00:13:34,800 Speaker 1: moments of the universe is called inflation, right, and that 256 00:13:35,080 --> 00:13:38,600 Speaker 1: sort of explains kind of what happened since the Big Bang, 257 00:13:38,800 --> 00:13:41,240 Speaker 1: but it doesn't quite explain what happened before. As we 258 00:13:41,280 --> 00:13:44,600 Speaker 1: go backwards in time from the cosmic microway background radiation, 259 00:13:44,840 --> 00:13:47,880 Speaker 1: we add this step where the universe expanded very dramatically 260 00:13:47,960 --> 00:13:50,920 Speaker 1: by a factor of ten to the thirty intend to 261 00:13:50,960 --> 00:13:53,920 Speaker 1: the minus thirty seconds, and then answers a lot of 262 00:13:53,960 --> 00:13:56,160 Speaker 1: the questions that we have about the wiggles and the 263 00:13:56,160 --> 00:13:59,480 Speaker 1: cosmic microwave background radiation. The temperature of the universe, and 264 00:13:59,559 --> 00:14:01,760 Speaker 1: we have a whole podcast episode about that you can 265 00:14:01,800 --> 00:14:04,320 Speaker 1: dig into. And so that's really cool. That's in a 266 00:14:04,440 --> 00:14:07,559 Speaker 1: huge advance, sort of like taking us yet further back. 267 00:14:07,720 --> 00:14:10,559 Speaker 1: But you know, we want to go to time equal zero, right. 268 00:14:10,720 --> 00:14:13,880 Speaker 1: Inflation takes us to time equals ten to the minus thirty, 269 00:14:14,080 --> 00:14:16,760 Speaker 1: but it doesn't explain how that got there, right. We 270 00:14:16,800 --> 00:14:19,560 Speaker 1: want to take the next step of that ladder backwards 271 00:14:19,600 --> 00:14:21,440 Speaker 1: in time. And that's the question that a lot of 272 00:14:21,440 --> 00:14:23,880 Speaker 1: these theories are probing, is trying to explain, like, how 273 00:14:23,920 --> 00:14:27,200 Speaker 1: did you get to inflation? What created the situation that 274 00:14:27,320 --> 00:14:30,800 Speaker 1: made this universe inflate in such an insane way? Yeah, 275 00:14:30,840 --> 00:14:33,840 Speaker 1: because we don't really know what causes that inflation, right, 276 00:14:33,880 --> 00:14:36,600 Speaker 1: I mean, it's something literally cost the universe to explode. 277 00:14:36,800 --> 00:14:39,960 Speaker 1: Something really made the universe explode and expand in this 278 00:14:40,040 --> 00:14:43,680 Speaker 1: crazy way, and we are just the beginning of understanding 279 00:14:43,720 --> 00:14:46,880 Speaker 1: what that might be. We're like putting together ridiculous sounding 280 00:14:46,960 --> 00:14:50,520 Speaker 1: theories to potentially explain how that might work. One of them, 281 00:14:50,520 --> 00:14:53,240 Speaker 1: for example, is that there was a field, a new 282 00:14:53,360 --> 00:14:56,480 Speaker 1: field that filled all the universe. You're familiar with, for example, 283 00:14:56,480 --> 00:15:00,400 Speaker 1: the electromagnetic field or gravitational fields, or the Higgs field. 284 00:15:00,600 --> 00:15:04,240 Speaker 1: Now imagine a new field, and it's called the inflaton field, 285 00:15:04,440 --> 00:15:06,760 Speaker 1: just to have a ridiculous name, and it's some new 286 00:15:06,960 --> 00:15:10,720 Speaker 1: kind of matter which expands super duper rapidly and for 287 00:15:10,760 --> 00:15:14,120 Speaker 1: some reason at some point decays into normal matter. And 288 00:15:14,200 --> 00:15:17,240 Speaker 1: that's one idea for like nucle eating our universe, that 289 00:15:17,320 --> 00:15:19,760 Speaker 1: the universe was filled with this in phloton field, which 290 00:15:19,760 --> 00:15:23,360 Speaker 1: at some point decayed into real matter, which then became 291 00:15:23,400 --> 00:15:25,880 Speaker 1: our universe. But of course that just you know, begs 292 00:15:25,920 --> 00:15:28,440 Speaker 1: more questions like well, where does the in photon field 293 00:15:28,480 --> 00:15:31,120 Speaker 1: come from? And what made that? And so you could 294 00:15:31,200 --> 00:15:33,600 Speaker 1: go on forever if you keep just sort of stacking 295 00:15:33,640 --> 00:15:36,200 Speaker 1: explanations on top of each other, which is why one 296 00:15:36,240 --> 00:15:39,680 Speaker 1: sort of attractive conceptual alternative is to try to sort 297 00:15:39,680 --> 00:15:42,040 Speaker 1: of loop it back to the end of the universe 298 00:15:42,080 --> 00:15:44,160 Speaker 1: and make your idea be a cycle which sort of 299 00:15:44,200 --> 00:15:48,840 Speaker 1: explains itself. All right, Well, let's get into this interesting 300 00:15:49,040 --> 00:15:53,680 Speaker 1: new theory, the conformal cyclic cosmology theory by Roger Penrose, 301 00:15:53,800 --> 00:15:55,960 Speaker 1: and let's talk about whether or not it could actually 302 00:15:56,040 --> 00:15:59,480 Speaker 1: let us see a little bit of the previous universe. 303 00:15:59,720 --> 00:16:14,400 Speaker 1: But let's take a quick break, all right, we're talking 304 00:16:14,480 --> 00:16:16,920 Speaker 1: about a small question, you know, where did the universe 305 00:16:16,960 --> 00:16:20,760 Speaker 1: come from? And has it always been here? And we 306 00:16:20,800 --> 00:16:23,400 Speaker 1: talked a little bit about the idea of inflation that 307 00:16:23,480 --> 00:16:27,120 Speaker 1: the universe somehow expanded really quickly at the beginning of time, 308 00:16:27,240 --> 00:16:29,200 Speaker 1: or the ti equals zero as we know it. But 309 00:16:29,240 --> 00:16:32,040 Speaker 1: the question is what happened before to equal zero? Time 310 00:16:32,040 --> 00:16:35,040 Speaker 1: equals zero in the universe? Was there a previous universe 311 00:16:35,160 --> 00:16:37,680 Speaker 1: or did the universe come out of nothing? And there's 312 00:16:37,680 --> 00:16:41,920 Speaker 1: this idea, Daniel, that maybe before our universe expanded, there 313 00:16:41,960 --> 00:16:45,320 Speaker 1: was another universe that maybe crunched together, and that's kind 314 00:16:45,320 --> 00:16:47,200 Speaker 1: of I think what a lot of people have heard about. 315 00:16:47,400 --> 00:16:50,280 Speaker 1: But you're saying that there's problems with this idea. Yeah, well, 316 00:16:50,320 --> 00:16:53,120 Speaker 1: one problem with that idea is that it starts from 317 00:16:53,160 --> 00:16:57,200 Speaker 1: a singularity. You know, you project backwards in time, our 318 00:16:57,320 --> 00:17:01,680 Speaker 1: universe gets more and more dense. Eventually it gets infinitely dense. 319 00:17:02,000 --> 00:17:04,240 Speaker 1: That's the singularity. You know. I think a lot of 320 00:17:04,240 --> 00:17:06,160 Speaker 1: people in their minds when they talk about the Big Bang, 321 00:17:06,200 --> 00:17:10,520 Speaker 1: they're imagining a very dense dot of matter in an empty, 322 00:17:10,560 --> 00:17:14,080 Speaker 1: infinite universe. But instead you should be imagining a universe 323 00:17:14,240 --> 00:17:17,560 Speaker 1: filled with stuff. But that stuff is of infinite density. 324 00:17:17,720 --> 00:17:19,600 Speaker 1: So the Big Bang, as we imagine, it's sort of 325 00:17:19,720 --> 00:17:23,520 Speaker 1: happened everywhere all at once. It's a question of density 326 00:17:23,640 --> 00:17:27,159 Speaker 1: rather than a question of location and matter exploding into 327 00:17:27,200 --> 00:17:31,000 Speaker 1: empty space. And the problem really is that singularity. The 328 00:17:31,040 --> 00:17:33,800 Speaker 1: singularity is not a physical thing. It's not something that 329 00:17:33,840 --> 00:17:36,920 Speaker 1: we can understand it. It reflects a breakdown in our theory. 330 00:17:37,000 --> 00:17:39,760 Speaker 1: General relativity tells us if you sort of follow its 331 00:17:39,840 --> 00:17:43,000 Speaker 1: laws naively, that things get denser and denser, and then 332 00:17:43,200 --> 00:17:46,000 Speaker 1: the curvature gets infinite as the density gets infinite. But 333 00:17:46,359 --> 00:17:49,080 Speaker 1: that's not something we can deal with. We can grapple with, 334 00:17:49,119 --> 00:17:52,280 Speaker 1: like general relativity fails when the curvature gets infinite. So 335 00:17:52,320 --> 00:17:54,920 Speaker 1: if you want to connect our universe to a previous 336 00:17:55,000 --> 00:17:58,320 Speaker 1: universe by saying it went through a singularity, then that's 337 00:17:58,359 --> 00:18:00,719 Speaker 1: kind of a problem because the singularity feels sort of 338 00:18:00,760 --> 00:18:03,960 Speaker 1: like nonsense. It feels like when the theory is failing, 339 00:18:04,280 --> 00:18:08,120 Speaker 1: when a theory needs a new idea. M hmmm, well, 340 00:18:08,240 --> 00:18:10,760 Speaker 1: it seems like maybe the real problem is that this 341 00:18:11,000 --> 00:18:14,520 Speaker 1: big bang and big crunch idea requires you to have 342 00:18:14,600 --> 00:18:16,359 Speaker 1: a big crunch, right, But we don't know if the 343 00:18:16,440 --> 00:18:19,919 Speaker 1: universe will actually come back together to create a big crunch. 344 00:18:20,200 --> 00:18:23,000 Speaker 1: That's right, You need some mechanism to reverse what we 345 00:18:23,040 --> 00:18:25,679 Speaker 1: see happening now. What we see happening now is that 346 00:18:25,720 --> 00:18:29,680 Speaker 1: the universe is expanding, and that expansion is accelerating. It's 347 00:18:29,720 --> 00:18:33,040 Speaker 1: happening faster and faster, So our universe certainly doesn't look 348 00:18:33,080 --> 00:18:35,520 Speaker 1: like it's heading for a big crunch. On the other hand, 349 00:18:35,520 --> 00:18:39,440 Speaker 1: we have no idea what's causing that expansion to accelerate. 350 00:18:39,640 --> 00:18:42,040 Speaker 1: There's some mechanism there that goes by the name of 351 00:18:42,119 --> 00:18:44,440 Speaker 1: dark energy, but we don't understand it, so we don't 352 00:18:44,440 --> 00:18:47,800 Speaker 1: know whether it will continue. Turned on about five billion 353 00:18:47,880 --> 00:18:51,119 Speaker 1: years ago, and it might turn off, it might turn around. 354 00:18:51,440 --> 00:18:54,440 Speaker 1: So we don't necessarily see a big crunch happening in 355 00:18:54,480 --> 00:18:56,760 Speaker 1: our universe. But we also can't really rule it out 356 00:18:56,800 --> 00:19:00,480 Speaker 1: because we just don't understand the basic mechanisms at play. 357 00:19:00,560 --> 00:19:02,600 Speaker 1: But you're right, if you want to have a big crunch, 358 00:19:02,720 --> 00:19:06,000 Speaker 1: something's got to do the crunching. Yeah, And we kind 359 00:19:06,000 --> 00:19:09,280 Speaker 1: of had this idea before we knew about the accelerating 360 00:19:09,320 --> 00:19:11,639 Speaker 1: expansion of the universe, Like before it made sense that 361 00:19:11,680 --> 00:19:13,479 Speaker 1: you know, the universe would kind of expand and then 362 00:19:13,520 --> 00:19:16,639 Speaker 1: gravity would win out at the end, and the universe 363 00:19:16,640 --> 00:19:20,800 Speaker 1: would contract and collapse back into a singularity perhaps and 364 00:19:20,800 --> 00:19:22,560 Speaker 1: then a none of the universe would come out of that. 365 00:19:22,800 --> 00:19:25,760 Speaker 1: But again, that requires you to have a big crunch. 366 00:19:25,760 --> 00:19:28,159 Speaker 1: And what happens if you can't really have a big crunch. 367 00:19:28,200 --> 00:19:30,760 Speaker 1: Does that mean that, you know, we can't have any 368 00:19:30,760 --> 00:19:34,200 Speaker 1: more universes, like we're the last one? Maybe? Yeah, Well 369 00:19:34,240 --> 00:19:37,800 Speaker 1: that's where Penrose's idea comes in. He has this concept 370 00:19:37,920 --> 00:19:41,840 Speaker 1: for allowing cycles even if the universe never crunches back. 371 00:19:42,080 --> 00:19:46,520 Speaker 1: That's sort of the heart of his idea, right, because well, 372 00:19:46,560 --> 00:19:48,639 Speaker 1: that would be the only thing that could work at 373 00:19:48,640 --> 00:19:50,719 Speaker 1: this point, right, because if we never have a big crunch, 374 00:19:50,840 --> 00:19:52,600 Speaker 1: like if a big crunch is not in our future 375 00:19:53,600 --> 00:19:56,440 Speaker 1: or any other universe that have was created like ours, 376 00:19:56,760 --> 00:19:58,720 Speaker 1: then this idea of a big crunch to a big 377 00:19:58,760 --> 00:20:01,480 Speaker 1: bang can't happen. Yeah, exactly. You can't go from crunch 378 00:20:01,520 --> 00:20:03,359 Speaker 1: to bang if you don't go to the crunch. So 379 00:20:03,400 --> 00:20:06,000 Speaker 1: there's two possibilities. It seems like either we're the only 380 00:20:06,080 --> 00:20:09,359 Speaker 1: in last verse because we're going to expand out into nothingness, 381 00:20:10,040 --> 00:20:12,480 Speaker 1: or maybe there's a clever new idea that let's just 382 00:20:12,760 --> 00:20:16,560 Speaker 1: come up with a new universe out of this infinite expansion. Yeah, 383 00:20:16,560 --> 00:20:20,040 Speaker 1: and that's Penrose's idea. He says, let's think about the 384 00:20:20,160 --> 00:20:23,399 Speaker 1: very very end of the universe and try to connect that, 385 00:20:23,480 --> 00:20:25,480 Speaker 1: try to loop that back to the beginning of the 386 00:20:25,560 --> 00:20:29,000 Speaker 1: universe without going through a big crunch. And what he 387 00:20:29,080 --> 00:20:31,720 Speaker 1: ends up doing is sort of like a weird mathematical trick, 388 00:20:31,800 --> 00:20:35,000 Speaker 1: which might be physical, but it sort of blows your mind. 389 00:20:35,040 --> 00:20:38,159 Speaker 1: It's pretty cool idea. So it is the idea that 390 00:20:38,200 --> 00:20:40,879 Speaker 1: it looped back to the beginning of our universe or 391 00:20:40,920 --> 00:20:43,399 Speaker 1: to the beginning of a different universe. The idea is 392 00:20:43,400 --> 00:20:46,040 Speaker 1: that it would begin a new universe. And here's the 393 00:20:46,080 --> 00:20:49,119 Speaker 1: basic concept. You think about the very very far future 394 00:20:49,119 --> 00:20:51,400 Speaker 1: of the universe. We're talking like ten to the one 395 00:20:51,480 --> 00:20:55,200 Speaker 1: hundred years. What's our prediction for how our universe will 396 00:20:55,200 --> 00:20:58,320 Speaker 1: look then, tend to the one hundred years, tend to 397 00:20:58,400 --> 00:21:01,639 Speaker 1: the one hundred. It's like a one with a hundred zeros. 398 00:21:01,960 --> 00:21:04,400 Speaker 1: It's a lot of years. It's like more than trillions, 399 00:21:04,400 --> 00:21:07,920 Speaker 1: it's like bazillions. I don't think we've even named those 400 00:21:07,960 --> 00:21:10,919 Speaker 1: scientific prefixes. You know, right, if the Universe is a 401 00:21:10,920 --> 00:21:13,880 Speaker 1: television series, we are like still in the opening credits 402 00:21:14,000 --> 00:21:17,040 Speaker 1: of episode one, right, because even a trillion years is 403 00:21:17,080 --> 00:21:19,159 Speaker 1: like one tend to the twelve. This is tend to 404 00:21:19,160 --> 00:21:21,359 Speaker 1: a hundred. Yeah, this is tend to the one hundred. 405 00:21:21,440 --> 00:21:24,120 Speaker 1: So it's just a ridiculous number. And you'll understand why 406 00:21:24,200 --> 00:21:26,600 Speaker 1: in a minute. Because he wants to get to the 407 00:21:26,640 --> 00:21:28,960 Speaker 1: point when the universe is smooth again. He wants to 408 00:21:28,960 --> 00:21:32,040 Speaker 1: wait for all the black holes to die. So the 409 00:21:32,160 --> 00:21:36,280 Speaker 1: current trajectory for our universe if nothing changes with dark energy, 410 00:21:36,520 --> 00:21:38,600 Speaker 1: is that everything is getting pulled apart. But you have 411 00:21:38,640 --> 00:21:43,000 Speaker 1: these local gravitational clumps like our galaxy and our solar system, 412 00:21:43,080 --> 00:21:46,840 Speaker 1: So those things will eventually collapse gravitationally, forming black holes, 413 00:21:47,119 --> 00:21:49,560 Speaker 1: and these black holes will get really really far apart 414 00:21:49,600 --> 00:21:52,240 Speaker 1: because of dark energy. Well, what happens to a black hole? 415 00:21:52,400 --> 00:21:55,320 Speaker 1: Do black holes live forever? We actually know that they don't. 416 00:21:55,400 --> 00:21:57,920 Speaker 1: Write Hawking radiation is a way that they can give 417 00:21:58,000 --> 00:22:01,840 Speaker 1: off little bits of energy really really massive black holes 418 00:22:01,840 --> 00:22:05,000 Speaker 1: and made a very very small amount of Hawking radiation. 419 00:22:05,200 --> 00:22:07,520 Speaker 1: So he's thinking in the deep, deep far future, when 420 00:22:07,560 --> 00:22:10,359 Speaker 1: you form all these black holes, they get separated by 421 00:22:10,440 --> 00:22:13,520 Speaker 1: dark energy, and then they leak their radiation back out 422 00:22:13,560 --> 00:22:15,720 Speaker 1: into the universe. You have to wait for them all 423 00:22:15,760 --> 00:22:19,520 Speaker 1: to die. So the end of our he calls them eon, 424 00:22:19,960 --> 00:22:21,720 Speaker 1: is when all of our black holes sort of just 425 00:22:21,800 --> 00:22:26,240 Speaker 1: turned into radiation. They basically evaporated into photons or or 426 00:22:26,280 --> 00:22:29,600 Speaker 1: what black holes evaporate into all kinds of things exactly. 427 00:22:29,600 --> 00:22:32,560 Speaker 1: They can evaporate into electrons or into other kinds of corks, 428 00:22:32,720 --> 00:22:35,400 Speaker 1: or into photons or whatever. So they've got to give 429 00:22:35,480 --> 00:22:38,159 Speaker 1: up all of their light. And then he's imagining this 430 00:22:38,240 --> 00:22:41,119 Speaker 1: universe is sort of smooth again, and he's trying to 431 00:22:41,119 --> 00:22:43,439 Speaker 1: make a connection between the end of our universe and 432 00:22:43,480 --> 00:22:46,119 Speaker 1: the start of the next universe. And the connection he 433 00:22:46,160 --> 00:22:48,840 Speaker 1: makes is like, well, our universe started out kind of 434 00:22:48,920 --> 00:22:52,680 Speaker 1: smooth before, like quantum fluctuations and everything and inflation blew 435 00:22:52,720 --> 00:22:55,840 Speaker 1: it up into actual interesting structure. So if the end 436 00:22:55,880 --> 00:22:58,320 Speaker 1: of the universe ends up sort of like smooth fields 437 00:22:58,320 --> 00:23:01,040 Speaker 1: of radiation, he's going to try to connect that to 438 00:23:01,080 --> 00:23:03,919 Speaker 1: the beginning of the next universe, which also starts smooth. 439 00:23:05,200 --> 00:23:07,439 Speaker 1: I feel like it's a little different because you know, 440 00:23:07,720 --> 00:23:11,640 Speaker 1: our universe that far into the future sounds kind of cold. 441 00:23:12,480 --> 00:23:14,760 Speaker 1: It might be smooth, and it might be you know, 442 00:23:14,880 --> 00:23:18,520 Speaker 1: kind of random and homogeneous, and there's electrons and quarks 443 00:23:18,520 --> 00:23:20,960 Speaker 1: flying around, but things are still pretty discreet, like things 444 00:23:20,960 --> 00:23:24,320 Speaker 1: are in the form of electrons or quarks. Right, it's 445 00:23:24,320 --> 00:23:26,480 Speaker 1: not like pure energy like we think of at the 446 00:23:26,480 --> 00:23:29,919 Speaker 1: beginning of our universe. Yeah, exactly. The density feels different. 447 00:23:30,000 --> 00:23:32,679 Speaker 1: And here's when the mathematical trip comes in. It turns 448 00:23:32,680 --> 00:23:35,919 Speaker 1: out that if our universe has only photons in it, 449 00:23:36,040 --> 00:23:39,359 Speaker 1: or more specifically, only massless particles in it, then you 450 00:23:39,400 --> 00:23:43,040 Speaker 1: can change the length scale of the universe without changing 451 00:23:43,119 --> 00:23:45,680 Speaker 1: any of the physics. You can say, what used to 452 00:23:45,720 --> 00:23:48,920 Speaker 1: be a light year is now a millimeter, and all 453 00:23:48,960 --> 00:23:52,480 Speaker 1: the physics will work the same. All the massless particles 454 00:23:52,480 --> 00:23:55,399 Speaker 1: will operate the same way they had before. They won't 455 00:23:55,440 --> 00:23:59,520 Speaker 1: notice what. Yeah, I thought particles had kind of like 456 00:23:59,560 --> 00:24:01,960 Speaker 1: a minimum distance to them. Well, these particles we don't 457 00:24:02,000 --> 00:24:04,000 Speaker 1: think of as having a size, right, We don't think 458 00:24:04,000 --> 00:24:07,080 Speaker 1: of the photon is having like a physical extent to it. 459 00:24:07,960 --> 00:24:09,840 Speaker 1: Just think of it. It's like a little blip in 460 00:24:09,880 --> 00:24:13,000 Speaker 1: the field. And these fields, at least the massless fields, 461 00:24:13,000 --> 00:24:15,840 Speaker 1: have this weird property that you can scale them by 462 00:24:15,840 --> 00:24:18,880 Speaker 1: a number and nothing will change. All the physics will 463 00:24:18,880 --> 00:24:20,959 Speaker 1: be the same. It's sort of like if we just 464 00:24:21,240 --> 00:24:25,000 Speaker 1: changed all the rulers and made everybody smaller. Nobody would 465 00:24:25,000 --> 00:24:27,600 Speaker 1: notice the difference, right, all of a sudden, we're all 466 00:24:27,760 --> 00:24:30,080 Speaker 1: much tinier than we were before. But we also changed 467 00:24:30,119 --> 00:24:32,600 Speaker 1: the rulers, so nobody can tell. If the laws of 468 00:24:32,640 --> 00:24:35,560 Speaker 1: physics are invariant to that kind of transformation, then you 469 00:24:35,560 --> 00:24:38,320 Speaker 1: wouldn't notice the difference. So he noticed this about the 470 00:24:38,440 --> 00:24:42,320 Speaker 1: universe very specifically that only has massless particles in it. 471 00:24:43,080 --> 00:24:45,520 Speaker 1: You can do this and not change anything. Doesn't work 472 00:24:45,560 --> 00:24:47,919 Speaker 1: if there are any particles that have mass. Right, But 473 00:24:48,000 --> 00:24:49,640 Speaker 1: it sounds like we skipped the step though, Like how 474 00:24:49,640 --> 00:24:52,680 Speaker 1: do we go from black holes evaporating into electrons and 475 00:24:52,760 --> 00:24:56,440 Speaker 1: cords to now everything just being photons? Yes, a very 476 00:24:56,480 --> 00:24:58,800 Speaker 1: good point. He did skip a step. But you know, 477 00:24:58,840 --> 00:25:01,679 Speaker 1: the way these theoretical laration's work is like, m that 478 00:25:01,720 --> 00:25:03,800 Speaker 1: seems like an unsolvable problem. He'll put it on the 479 00:25:03,800 --> 00:25:07,359 Speaker 1: shelf for now and get back to it. What what 480 00:25:07,400 --> 00:25:09,560 Speaker 1: do you mean? I mean because we talked about how 481 00:25:09,600 --> 00:25:13,480 Speaker 1: an electron well might never decay, right, Yeah, exactly, He's 482 00:25:13,520 --> 00:25:16,240 Speaker 1: got a problem with electrons. You know, like most particles 483 00:25:16,240 --> 00:25:19,320 Speaker 1: in the universe, top corks takes bosons will decay and 484 00:25:19,359 --> 00:25:21,880 Speaker 1: go down to lighter and lighter particles. And there's only 485 00:25:21,920 --> 00:25:24,280 Speaker 1: a very small number of particles in the universe that 486 00:25:24,359 --> 00:25:27,040 Speaker 1: are stable. And so the photon, for example, is stable. 487 00:25:27,200 --> 00:25:28,879 Speaker 1: You can have a photon, it can hang out forever, 488 00:25:29,000 --> 00:25:32,720 Speaker 1: it can fly across the universe. But also electrons are stable. 489 00:25:32,880 --> 00:25:34,760 Speaker 1: We don't know of any way for an electron to 490 00:25:34,840 --> 00:25:37,920 Speaker 1: turn into something lighter, right or quarks? Right aren't? Don't 491 00:25:38,000 --> 00:25:40,680 Speaker 1: quarks also last forever, like if they're in a proton. Yeah, 492 00:25:40,760 --> 00:25:43,080 Speaker 1: quarks can last forever. They can turn into other stuff. 493 00:25:43,119 --> 00:25:47,000 Speaker 1: But basically quarks can last forever. Protons, however, might decay, right, 494 00:25:47,040 --> 00:25:50,200 Speaker 1: We don't know. Protons we think last forever. We've never 495 00:25:50,240 --> 00:25:52,400 Speaker 1: seen one decay, but there are some theories in which 496 00:25:52,440 --> 00:25:55,160 Speaker 1: they can decay into lighter stuff. But you'd be stuck 497 00:25:55,200 --> 00:25:58,119 Speaker 1: with some massive particles. And so to go from a 498 00:25:58,240 --> 00:26:01,320 Speaker 1: universe that has like photons and a few electrons in 499 00:26:01,320 --> 00:26:04,320 Speaker 1: it to universe with just photons, he has to invent 500 00:26:04,400 --> 00:26:06,600 Speaker 1: some sort of new physics thing, and he calls it 501 00:26:06,640 --> 00:26:09,480 Speaker 1: the arab On field that turns all these massive particles 502 00:26:09,520 --> 00:26:13,159 Speaker 1: somehow now into photons. He calls it the wave my 503 00:26:13,280 --> 00:26:17,639 Speaker 1: hand fee field. It's very hand wavy. But you know, 504 00:26:17,800 --> 00:26:20,160 Speaker 1: Penrose is a big thinker. He's like trying to get 505 00:26:20,160 --> 00:26:22,000 Speaker 1: the big structure right. He's like, you know, can I 506 00:26:22,280 --> 00:26:24,680 Speaker 1: somehow work out this bigger problem, then I'll come back 507 00:26:24,760 --> 00:26:27,040 Speaker 1: in and patch up these other holes and see if 508 00:26:27,080 --> 00:26:29,639 Speaker 1: I can find something that fills them in m M. 509 00:26:30,080 --> 00:26:33,400 Speaker 1: So he's saying, let's say that eventually, maybe in a 510 00:26:33,440 --> 00:26:38,639 Speaker 1: long time, all matter particles decay into massless photons or 511 00:26:38,720 --> 00:26:41,880 Speaker 1: massless particles. Right, that's the that's the leap of faith here, 512 00:26:42,520 --> 00:26:45,560 Speaker 1: and then that creates a state that's basically pure energy, right, 513 00:26:45,600 --> 00:26:48,440 Speaker 1: in which case it's sort of scale less, like it's 514 00:26:48,520 --> 00:26:51,280 Speaker 1: a millimeter and of a light ear make no difference 515 00:26:51,320 --> 00:26:53,720 Speaker 1: between the two. Exactly, it's scale less, so you can 516 00:26:53,800 --> 00:26:56,439 Speaker 1: change your scale and nothing is different because things that 517 00:26:56,480 --> 00:26:59,120 Speaker 1: don't have mass. Our skill is yeah, exactly. A photon 518 00:26:59,280 --> 00:27:02,280 Speaker 1: sees the whole universe anyway, is shrunk and to a point, right, 519 00:27:02,280 --> 00:27:04,280 Speaker 1: it's moving at the speed of light, and so distance 520 00:27:04,320 --> 00:27:07,160 Speaker 1: doesn't really make any difference to the photons. The whole 521 00:27:07,280 --> 00:27:10,520 Speaker 1: universe is length contracted anyway, it doesn't matter ten light years, 522 00:27:10,560 --> 00:27:14,439 Speaker 1: one light year, one millimeter, like space itself. The idea 523 00:27:14,440 --> 00:27:17,280 Speaker 1: of distance doesn't make sense anymore, or at least if 524 00:27:17,320 --> 00:27:20,880 Speaker 1: you scale everything the same way, nothing changes. And so 525 00:27:20,960 --> 00:27:24,320 Speaker 1: he says, well, let's take this huge expanded universe and 526 00:27:24,320 --> 00:27:27,040 Speaker 1: then just sort of like redefine it to be a 527 00:27:27,160 --> 00:27:31,240 Speaker 1: very dense, smooth universe, and boom, you have the conditions 528 00:27:31,320 --> 00:27:34,679 Speaker 1: that were at the beginning of our universe. Right at 529 00:27:34,720 --> 00:27:36,720 Speaker 1: the beginning of our universe there was a state. We 530 00:27:36,760 --> 00:27:39,200 Speaker 1: don't understand it, but it's postulated that it was there, 531 00:27:39,200 --> 00:27:41,359 Speaker 1: and it was very very dense with energy, and it 532 00:27:41,400 --> 00:27:43,679 Speaker 1: was very smooth, and that that then, you know, expanded 533 00:27:43,880 --> 00:27:46,800 Speaker 1: to turn into our universe. The image of penrose Is 534 00:27:46,920 --> 00:27:50,600 Speaker 1: universe is like every universe is a further expansion on 535 00:27:50,720 --> 00:27:53,760 Speaker 1: the previous one. It's like this endless series of expansions. 536 00:27:53,800 --> 00:27:57,680 Speaker 1: We just redefine the terms. Wow, but then each new 537 00:27:57,800 --> 00:28:01,360 Speaker 1: universe is bigger than less, yes, by a lot exactly. 538 00:28:01,400 --> 00:28:04,080 Speaker 1: We just keep changing the scale. So the whole previous 539 00:28:04,200 --> 00:28:06,960 Speaker 1: universe would be contained within like a tiny dot of 540 00:28:06,960 --> 00:28:10,240 Speaker 1: our universe, and our entire universe would be contained within 541 00:28:10,240 --> 00:28:13,040 Speaker 1: a tiny dot of the next one, kind of like 542 00:28:13,040 --> 00:28:16,320 Speaker 1: a Russian doll, but at a ginormous scale, yes, and 543 00:28:16,480 --> 00:28:20,800 Speaker 1: going on forever backwards and forwards in time, backwards and 544 00:28:20,880 --> 00:28:23,160 Speaker 1: forwards in time exactly. And so he gets this sort 545 00:28:23,160 --> 00:28:26,240 Speaker 1: of like cyclic structure where the end of the universe 546 00:28:26,280 --> 00:28:29,119 Speaker 1: connects to the beginning of the universe. But it doesn't 547 00:28:29,160 --> 00:28:31,320 Speaker 1: have to have a crunch, right, doesn't need to explain 548 00:28:31,359 --> 00:28:33,640 Speaker 1: the crunch. He needs lots of other stuff he's got 549 00:28:33,640 --> 00:28:36,399 Speaker 1: to explain to me work, but he doesn't need the crunch. 550 00:28:36,640 --> 00:28:40,640 Speaker 1: And there's a big advantage there because the crunch destroys 551 00:28:40,720 --> 00:28:43,120 Speaker 1: all the information. Like, if there was a crunch, then 552 00:28:43,120 --> 00:28:45,680 Speaker 1: it went through a singularity and any information about that 553 00:28:45,720 --> 00:28:49,800 Speaker 1: previous universe is gone, it's destroyed. But if this series 554 00:28:49,840 --> 00:28:53,880 Speaker 1: of infinite expansions is remapping and then expansion, then you 555 00:28:53,920 --> 00:28:58,040 Speaker 1: could find traces of the previous universe in our universe. Right, 556 00:28:58,040 --> 00:29:00,479 Speaker 1: it's kind of like a more like a blooming universe 557 00:29:00,600 --> 00:29:05,640 Speaker 1: rather than a sickly universe. Yeah, exactly. It's pedals within 558 00:29:05,680 --> 00:29:09,240 Speaker 1: pedals within pedals, right, each one nested within the previous one, 559 00:29:09,800 --> 00:29:12,200 Speaker 1: like an infinite fractal or something. Yeah, it's like a 560 00:29:12,280 --> 00:29:15,400 Speaker 1: fractal universe theory. It's pretty cool, all right. Well, let's 561 00:29:15,440 --> 00:29:18,080 Speaker 1: get into whether or not this theory even makes sense 562 00:29:19,080 --> 00:29:22,080 Speaker 1: it may not, and talk about whether or not there 563 00:29:22,160 --> 00:29:25,560 Speaker 1: is evidence out there in the cosmic microwave background radiation 564 00:29:26,320 --> 00:29:29,520 Speaker 1: to support this theory. But first, let's take a quick break. 565 00:29:42,320 --> 00:29:46,480 Speaker 1: All right, we're talking about the infinite universe as a 566 00:29:46,560 --> 00:29:51,680 Speaker 1: Russian doll theory. This is Roger Penrose's conformal sickly cosmology 567 00:29:51,760 --> 00:29:56,320 Speaker 1: theory that says that the universe came from another universe 568 00:29:56,360 --> 00:30:00,320 Speaker 1: expanding infinitely out, and that after our universe expand ends 569 00:30:00,360 --> 00:30:03,640 Speaker 1: almost infinitely out, another universe will grow from that state 570 00:30:03,640 --> 00:30:06,320 Speaker 1: of pure energy you should measure like a trumpet with 571 00:30:06,320 --> 00:30:08,440 Speaker 1: its horn, and then another one coming out of its horn, 572 00:30:08,480 --> 00:30:10,480 Speaker 1: another one coming out of its horn, and it's just 573 00:30:10,720 --> 00:30:14,480 Speaker 1: like endless cycle of growth. So I'm curious, or what 574 00:30:14,600 --> 00:30:16,400 Speaker 1: would you have named this theory if you could come 575 00:30:16,440 --> 00:30:20,120 Speaker 1: up with it the trumpet theory? They had the Russian 576 00:30:20,160 --> 00:30:24,120 Speaker 1: ball theory. I don't know. I think cycles cycled though. 577 00:30:24,120 --> 00:30:26,240 Speaker 1: It is kind of a weird name though, because it's 578 00:30:26,240 --> 00:30:28,560 Speaker 1: not quite a cycle, right, It's more like a blooming 579 00:30:28,640 --> 00:30:31,320 Speaker 1: universe theory maybe, yeah, big bloom, there you go. It 580 00:30:31,360 --> 00:30:33,760 Speaker 1: doesn't run the same forwards and backwards, right, It doesn't 581 00:30:33,760 --> 00:30:36,320 Speaker 1: have that sort of time symmetry to it. It definitely 582 00:30:36,320 --> 00:30:39,880 Speaker 1: just keeps expanding as time goes forwards. So the thing 583 00:30:39,920 --> 00:30:42,720 Speaker 1: I like about the Big Crunch Big Bang idea is 584 00:30:42,760 --> 00:30:44,760 Speaker 1: that it does have some sort of time symmetry. You 585 00:30:44,760 --> 00:30:46,880 Speaker 1: can imagine running things backwards and time and it would 586 00:30:46,920 --> 00:30:49,880 Speaker 1: look sort of the same. All right, So let's talk 587 00:30:49,880 --> 00:30:52,080 Speaker 1: about whether this makes sense. This is something that the 588 00:30:52,080 --> 00:30:55,200 Speaker 1: physicists are actually considering. Like, I know, he won a 589 00:30:55,240 --> 00:30:57,000 Speaker 1: Nobel Prize, but he didn't win a Nobel price for 590 00:30:57,040 --> 00:30:59,960 Speaker 1: this theory. No, there are a lot of things named 591 00:31:00,120 --> 00:31:04,120 Speaker 1: after Penrose in physics Penrose diagrams, Penrose tilings, and he 592 00:31:04,240 --> 00:31:06,760 Speaker 1: recently won a Nobel Prize for thinking about black hole. 593 00:31:06,880 --> 00:31:09,800 Speaker 1: So definitely a smart guy. But a lot of these 594 00:31:10,000 --> 00:31:13,120 Speaker 1: really smart physicists get famous for a few ideas, and 595 00:31:13,280 --> 00:31:15,960 Speaker 1: those few ideas are like a small fraction of all 596 00:31:16,000 --> 00:31:18,680 Speaker 1: the ideas they toss out there and see which one sticks. 597 00:31:18,720 --> 00:31:21,040 Speaker 1: So often they come up with a lot of crazy, 598 00:31:21,080 --> 00:31:24,120 Speaker 1: bonkers ideas that you know, never really hang together. So 599 00:31:24,240 --> 00:31:27,280 Speaker 1: this is not one that's in the main stream of cosmology, Like, 600 00:31:27,320 --> 00:31:29,000 Speaker 1: this is not one that a lot of people are 601 00:31:29,040 --> 00:31:32,080 Speaker 1: working on. And Penrose proposed in about two thousand and 602 00:31:32,080 --> 00:31:34,800 Speaker 1: twelve in a paper in a book, and it got 603 00:31:34,840 --> 00:31:37,360 Speaker 1: a lot of attention for a while also because he 604 00:31:37,480 --> 00:31:40,480 Speaker 1: claimed he could actually see the evidence of a previous 605 00:31:40,560 --> 00:31:45,280 Speaker 1: universe m so meaning it sort of works mathematically like 606 00:31:45,320 --> 00:31:47,520 Speaker 1: if we can get the universe to this state of 607 00:31:47,640 --> 00:31:51,160 Speaker 1: pure energy without any massive particles, then the math does 608 00:31:51,280 --> 00:31:53,960 Speaker 1: kind of suggest that you could get another universe out 609 00:31:53,960 --> 00:31:57,120 Speaker 1: of that. Yeah, so that's what made it interesting. Yeah, mathematically, 610 00:31:57,160 --> 00:31:59,600 Speaker 1: there is an idea there that you can map the 611 00:31:59,680 --> 00:32:02,800 Speaker 1: end of our universe to the beginning of our universe 612 00:32:02,840 --> 00:32:05,320 Speaker 1: that have a very similar sort of structure to them. 613 00:32:05,360 --> 00:32:07,600 Speaker 1: So there is a cool idea there. But you know, 614 00:32:07,880 --> 00:32:10,640 Speaker 1: you gotta stick in something that makes the universe turned 615 00:32:10,680 --> 00:32:14,160 Speaker 1: into just photons, and that's not something we understand at all. 616 00:32:14,320 --> 00:32:16,560 Speaker 1: And then you also got to look for the evidence 617 00:32:16,560 --> 00:32:18,600 Speaker 1: of it. You know. The best theories are ones that 618 00:32:18,720 --> 00:32:21,960 Speaker 1: make predictions and say, if this is true, there would 619 00:32:21,960 --> 00:32:25,160 Speaker 1: be some sort of like indistinguishable mark in the universe. 620 00:32:25,360 --> 00:32:28,080 Speaker 1: That's what was so exciting. For example, about the cosmic 621 00:32:28,120 --> 00:32:31,880 Speaker 1: microwave background radiation. It was predicted people said, well, if 622 00:32:31,880 --> 00:32:33,560 Speaker 1: there was a big bang, then there should have been 623 00:32:33,560 --> 00:32:37,200 Speaker 1: this moment when the universe went from opaque plasma to 624 00:32:37,400 --> 00:32:40,640 Speaker 1: transparent neutral ions and we should be able to see it. 625 00:32:40,960 --> 00:32:43,720 Speaker 1: And so that's pretty awesome to actually go out and 626 00:32:43,760 --> 00:32:46,720 Speaker 1: find that fingerprint that you predicted. So then Penrose, you know, 627 00:32:46,760 --> 00:32:48,960 Speaker 1: he rose to this challenge and he made predictions for 628 00:32:49,040 --> 00:32:53,120 Speaker 1: what he said should be out there evidence of previous universes, right, 629 00:32:53,200 --> 00:32:56,120 Speaker 1: and so he looked in the cosmic microwave background radiation 630 00:32:56,440 --> 00:32:58,480 Speaker 1: and what did he see? Did he see evidence for 631 00:32:58,520 --> 00:33:01,960 Speaker 1: this blooming universe theory? The big bloom he actually did. 632 00:33:02,040 --> 00:33:06,840 Speaker 1: He claimed very significant evidence of previous universes in the 633 00:33:06,880 --> 00:33:10,320 Speaker 1: cosmic microwave background radiation. And the way he thought it 634 00:33:10,320 --> 00:33:14,040 Speaker 1: would look are these things called Hawking points. And Hawking 635 00:33:14,120 --> 00:33:17,880 Speaker 1: point is where there was a huge supermassive black hole 636 00:33:18,040 --> 00:33:21,240 Speaker 1: in the previous universe which then evaporated. But a left 637 00:33:21,280 --> 00:33:23,280 Speaker 1: sort of a mark is a place in that universe 638 00:33:23,280 --> 00:33:26,520 Speaker 1: where there's maybe more radiation density than others. It's like 639 00:33:26,720 --> 00:33:29,480 Speaker 1: a non smoothness in the previous universe because you had 640 00:33:29,720 --> 00:33:33,000 Speaker 1: so much radiation from this really massive black hole, and 641 00:33:33,000 --> 00:33:34,880 Speaker 1: then when you map it back to the beginning of 642 00:33:34,880 --> 00:33:37,960 Speaker 1: the universe, it sort of gets squeezed down. You squeeze 643 00:33:37,960 --> 00:33:40,720 Speaker 1: all that radiation together and it makes basically a little 644 00:33:40,760 --> 00:33:44,800 Speaker 1: hot spot in the next universe. So every supermassive black 645 00:33:44,840 --> 00:33:47,360 Speaker 1: hole should leave like a little hot spot in the 646 00:33:47,400 --> 00:33:50,960 Speaker 1: next universe, and that should be seen in the cosmic 647 00:33:51,040 --> 00:33:53,680 Speaker 1: microwave background radiation. You should get like a little bit 648 00:33:53,680 --> 00:33:56,080 Speaker 1: of a warm spot in that radiation, like a little 649 00:33:56,080 --> 00:33:58,720 Speaker 1: scar kind of from the previous universe. Yeah, like a 650 00:33:58,720 --> 00:34:02,240 Speaker 1: little scar. And so the cosmic microwave background radiation, you know, 651 00:34:02,280 --> 00:34:04,560 Speaker 1: it's data that's out there. It's public. Anybody can go 652 00:34:04,640 --> 00:34:07,600 Speaker 1: download it and look at it and analyze it. It's complicated, 653 00:34:07,840 --> 00:34:09,279 Speaker 1: you know, you've got to really be an expert to 654 00:34:09,360 --> 00:34:12,239 Speaker 1: understand what you're seeing. But when Penrose put out this theory, 655 00:34:12,280 --> 00:34:15,840 Speaker 1: he also put out a paper claiming six sigma discovery 656 00:34:16,000 --> 00:34:20,160 Speaker 1: of twenty Hawking points in the cosmic microwave background radiation. 657 00:34:20,360 --> 00:34:22,600 Speaker 1: That means that he was claiming to see something that 658 00:34:22,680 --> 00:34:26,360 Speaker 1: was not just like random fluctuations of noise. Six sigma 659 00:34:26,400 --> 00:34:28,200 Speaker 1: means that he's like ruled out the fact that this 660 00:34:28,239 --> 00:34:31,080 Speaker 1: could just happen by random chance. He was very convinced 661 00:34:31,080 --> 00:34:34,520 Speaker 1: he was actually seeing these Hawking points super massive black 662 00:34:34,520 --> 00:34:39,160 Speaker 1: holes from a previous universe. Alright, So the idea is that, 663 00:34:39,239 --> 00:34:41,680 Speaker 1: you know, in the previous universe there probably were a 664 00:34:41,719 --> 00:34:43,839 Speaker 1: lot of super massive black holes, or are you saying 665 00:34:43,880 --> 00:34:45,839 Speaker 1: there was just one. No, they were probably a lot 666 00:34:45,840 --> 00:34:48,719 Speaker 1: to you know, yeah, because everything would eventually crunch into 667 00:34:48,760 --> 00:34:50,840 Speaker 1: a black hole, and those black holes might crunch together, 668 00:34:50,880 --> 00:34:53,239 Speaker 1: and so you in the previous universe, if you run 669 00:34:53,280 --> 00:34:56,080 Speaker 1: time long enough, you get these super massive black holes. 670 00:34:56,200 --> 00:34:59,880 Speaker 1: And he's saying that even these kind of super massive 671 00:35:00,120 --> 00:35:03,319 Speaker 1: holes would survive this process that makes everything massless, or 672 00:35:03,400 --> 00:35:06,400 Speaker 1: some evidence of them would survive, and that would survive 673 00:35:06,480 --> 00:35:10,360 Speaker 1: also this reblooming of the universe. Yeah, exactly. Their radiation 674 00:35:10,400 --> 00:35:13,160 Speaker 1: would leave like a little warm spot when the universe 675 00:35:13,280 --> 00:35:16,600 Speaker 1: blooms to the next eon. And because they're so massive, 676 00:35:16,760 --> 00:35:18,920 Speaker 1: that would be enough radiation that it would sort of 677 00:35:19,000 --> 00:35:21,800 Speaker 1: leak through a little bit. Remember, that's maybe the fate 678 00:35:21,840 --> 00:35:24,920 Speaker 1: of every galaxy. Every galaxy has at its heart a 679 00:35:24,960 --> 00:35:27,320 Speaker 1: big black hole. And the reason that we haven't fallen 680 00:35:27,320 --> 00:35:29,399 Speaker 1: into that black hole is just because we have enough 681 00:35:29,400 --> 00:35:31,920 Speaker 1: sort of speed to zip around it the way the 682 00:35:31,920 --> 00:35:34,479 Speaker 1: Earth zips around the Sun. But eventually we can lose 683 00:35:34,520 --> 00:35:36,799 Speaker 1: that speed. We can radiate off energy or collide with 684 00:35:36,840 --> 00:35:39,600 Speaker 1: stars and the fate of basically everything is eventually to 685 00:35:39,640 --> 00:35:42,800 Speaker 1: fall into that black hole and make it even more massive. 686 00:35:43,120 --> 00:35:45,560 Speaker 1: So the whole Milty Way will eventually be a supermassive 687 00:35:45,600 --> 00:35:48,960 Speaker 1: black hole and then evaporate its energy through Hawking radiation 688 00:35:49,200 --> 00:35:51,560 Speaker 1: m M. And so in this theory, you don't need 689 00:35:51,760 --> 00:35:55,480 Speaker 1: perfect smoothness in the universe to retrigger a new universe. 690 00:35:55,760 --> 00:35:57,799 Speaker 1: You can have these kind of hot spots. You can 691 00:35:57,840 --> 00:35:59,680 Speaker 1: have these little hot spots which you need is the 692 00:35:59,719 --> 00:36:03,200 Speaker 1: universe is only filled with massless particles, and then you 693 00:36:03,200 --> 00:36:06,400 Speaker 1: can map it back down to a new universe. So 694 00:36:06,719 --> 00:36:09,840 Speaker 1: this is pretty exciting. People like wow. Penrose claims he 695 00:36:09,920 --> 00:36:13,000 Speaker 1: sees like an imprint of a previous universe. That's sort 696 00:36:13,040 --> 00:36:16,799 Speaker 1: of amazing, right, But but of course we don't think 697 00:36:16,840 --> 00:36:19,240 Speaker 1: we live in these universe Nobody takes this theory seriously. 698 00:36:19,480 --> 00:36:21,919 Speaker 1: And the reason is that other people went and looked 699 00:36:21,920 --> 00:36:23,960 Speaker 1: at the data. They downloaded it and they analyzed it. 700 00:36:24,000 --> 00:36:25,600 Speaker 1: And there are a lot of experts out there who 701 00:36:25,600 --> 00:36:28,360 Speaker 1: really know what they're doing, and they didn't see these things. 702 00:36:28,640 --> 00:36:31,360 Speaker 1: They don't see these circles that Penrose claims he sees 703 00:36:31,400 --> 00:36:35,239 Speaker 1: with six sigma confidence. Yeah, exactly. He claims he saw them, 704 00:36:35,480 --> 00:36:37,840 Speaker 1: and they analyze them and they didn't see them. And 705 00:36:37,880 --> 00:36:41,040 Speaker 1: then multiple other groups analyzed them and they also didn't 706 00:36:41,080 --> 00:36:43,920 Speaker 1: see them. What like, isn't the data there? How can 707 00:36:43,960 --> 00:36:46,440 Speaker 1: some people see something and others not. Well, it depends 708 00:36:46,440 --> 00:36:48,600 Speaker 1: on how you're analyzing the data. You know, there's a 709 00:36:48,640 --> 00:36:51,440 Speaker 1: lot of steps involved in the assumptions you're making and 710 00:36:51,640 --> 00:36:54,160 Speaker 1: how you're calculating these things. And for a while nobody 711 00:36:54,160 --> 00:36:57,359 Speaker 1: could reproduce pen Rose's team's results, and then people found 712 00:36:57,360 --> 00:36:59,520 Speaker 1: the mistake. Turns out he had run some sort of 713 00:36:59,560 --> 00:37:03,120 Speaker 1: special version of an analysis code that nobody else agreed 714 00:37:03,200 --> 00:37:06,240 Speaker 1: was really accurate, and he wasn't really comparing what everybody 715 00:37:06,320 --> 00:37:09,400 Speaker 1: understood to be the predictions for Hawking points to the 716 00:37:09,440 --> 00:37:13,800 Speaker 1: actual data. It sort of felt a little bit cooked up. Alright, 717 00:37:13,840 --> 00:37:17,120 Speaker 1: So then maybe what he saw wasn't there. But that 718 00:37:17,160 --> 00:37:20,200 Speaker 1: doesn't mean I guess that the theory is necessarily wrong, right, 719 00:37:20,440 --> 00:37:22,560 Speaker 1: It doesn't mean the theory is wrong. And in the 720 00:37:22,640 --> 00:37:25,200 Speaker 1: last decade or so he's come up with other predictions, 721 00:37:25,239 --> 00:37:26,920 Speaker 1: you know, he said, oh, well, if my theory is right, 722 00:37:26,920 --> 00:37:30,360 Speaker 1: then we should see some interesting pattern of gravitational waves 723 00:37:30,520 --> 00:37:33,480 Speaker 1: or various other predictions so he still believes in it, 724 00:37:33,600 --> 00:37:36,040 Speaker 1: he's still talking about it, he's still excited about it, 725 00:37:36,160 --> 00:37:38,680 Speaker 1: he still makes up ideas for how we could test it. 726 00:37:38,880 --> 00:37:41,920 Speaker 1: And you're right, it's not something we've ruled out. You know, 727 00:37:42,120 --> 00:37:44,160 Speaker 1: maybe that we don't see those hawking points, but maybe 728 00:37:44,160 --> 00:37:46,840 Speaker 1: we just haven't looked, or maybe they're too subtle, or 729 00:37:46,880 --> 00:37:49,080 Speaker 1: maybe there are other ways to test this theory. And 730 00:37:49,200 --> 00:37:51,240 Speaker 1: this is a challenge for a lot of these theories. 731 00:37:51,239 --> 00:37:55,000 Speaker 1: You know, many cosmologies don't predict things that we can test. 732 00:37:55,000 --> 00:37:57,279 Speaker 1: They're talking about things that happened a long time ago 733 00:37:57,320 --> 00:38:00,319 Speaker 1: a really tiny scales, and it's hard to them up 734 00:38:00,320 --> 00:38:03,080 Speaker 1: with an experiment to test these things. So kudos to 735 00:38:03,160 --> 00:38:05,400 Speaker 1: him for coming up in the new cosmology and a 736 00:38:05,400 --> 00:38:07,920 Speaker 1: way to test it. That's pretty awesome. Yeah, And it's 737 00:38:07,960 --> 00:38:11,200 Speaker 1: not like we have a lot of other ideas line around, right, 738 00:38:11,360 --> 00:38:13,520 Speaker 1: Like we have no idea what happened before the Big Bang. 739 00:38:13,560 --> 00:38:16,000 Speaker 1: There's no real theory, and the theory of a big 740 00:38:16,040 --> 00:38:18,960 Speaker 1: crunch may never happen or may never have happened, yeah, 741 00:38:19,000 --> 00:38:22,200 Speaker 1: and may not be testable. So it's definitely a time 742 00:38:22,239 --> 00:38:24,319 Speaker 1: when people should be creative and it should be out 743 00:38:24,320 --> 00:38:28,600 Speaker 1: there exploring and creating new ideas and thinking broadly about 744 00:38:28,719 --> 00:38:31,319 Speaker 1: what could explain the universe that we see. Right, it's 745 00:38:31,360 --> 00:38:33,960 Speaker 1: time to go big, think creatively. Yeah. And one of 746 00:38:33,960 --> 00:38:36,680 Speaker 1: my favorite quotes from Penrose about this theory is what 747 00:38:36,840 --> 00:38:40,040 Speaker 1: he says, and I quote, of course the theory is crazy, 748 00:38:40,280 --> 00:38:42,920 Speaker 1: but I strongly believe that we have to take it seriously. 749 00:38:43,960 --> 00:38:46,040 Speaker 1: He's like, it's a crazy theory, but it's also a 750 00:38:46,080 --> 00:38:49,560 Speaker 1: crazy universe. Exactly, it's a crazy universe. It's gonna need 751 00:38:49,600 --> 00:38:52,400 Speaker 1: a crazy explanation. And also we got to be creative. 752 00:38:52,440 --> 00:38:54,320 Speaker 1: You know, sometimes you come up with a bad idea, 753 00:38:54,400 --> 00:38:57,920 Speaker 1: but it stimulates other better ideas in other theorists, so 754 00:38:57,960 --> 00:39:00,239 Speaker 1: you shouldn't just you know, like only share your only 755 00:39:00,280 --> 00:39:03,560 Speaker 1: finished ideas. There's a marketplace is a conversation of ideas. 756 00:39:03,760 --> 00:39:06,919 Speaker 1: That's how we get to these answers, right, yeah, physics mart. 757 00:39:07,080 --> 00:39:09,400 Speaker 1: That's where you go and buy ideas off the shelf. 758 00:39:09,880 --> 00:39:11,640 Speaker 1: I think it was more like a salon, you know, 759 00:39:12,200 --> 00:39:14,840 Speaker 1: sipping tea and chatting about our ideas about the universe. 760 00:39:17,000 --> 00:39:21,640 Speaker 1: Al Right, Well that's Roger Penrose is conformal cyclic cosmology, 761 00:39:21,840 --> 00:39:23,919 Speaker 1: and it kind of gets you to think about where 762 00:39:23,960 --> 00:39:27,600 Speaker 1: the universe came from, and whether distance really means anything 763 00:39:27,600 --> 00:39:30,160 Speaker 1: at all, because apparently it doesn't. If you're a photon, 764 00:39:30,320 --> 00:39:33,520 Speaker 1: then it certainly doesn't. You're happy to rescale an entirely 765 00:39:33,719 --> 00:39:37,800 Speaker 1: enormous inflated universe down to a tiny, little dense universe. 766 00:39:38,640 --> 00:39:43,080 Speaker 1: To photon, a millimeter is the same as a light year, exactly. 767 00:39:43,280 --> 00:39:45,359 Speaker 1: It takes the same amount of time. So if you're 768 00:39:45,400 --> 00:39:47,680 Speaker 1: building a house for a photon, you know, don't worry 769 00:39:47,680 --> 00:39:50,160 Speaker 1: so much abou getting the measurements right. And if you 770 00:39:50,160 --> 00:39:53,919 Speaker 1: can save yourself a lot of a building equipment, make 771 00:39:53,960 --> 00:39:56,719 Speaker 1: it a millimeter pig. All right, Well, that gives us 772 00:39:56,760 --> 00:39:58,879 Speaker 1: all a lot to think about and to think about 773 00:39:58,880 --> 00:40:01,359 Speaker 1: our origins and we're we came from? And could there 774 00:40:01,400 --> 00:40:04,400 Speaker 1: have been other universes before hours? Like maybe are we 775 00:40:04,719 --> 00:40:08,480 Speaker 1: season two hundred and seventy sevens of the Universe series 776 00:40:08,600 --> 00:40:10,879 Speaker 1: when the writers finally figure out what's going to happen 777 00:40:10,920 --> 00:40:15,040 Speaker 1: to these characters when we jumped to Shark twenty universes ago. 778 00:40:16,160 --> 00:40:18,399 Speaker 1: All right, we hope you enjoyed that. Thanks for joining us, 779 00:40:19,040 --> 00:40:28,920 Speaker 1: see you next time. Thanks for listening, and remember that 780 00:40:29,040 --> 00:40:31,800 Speaker 1: Daniel and Jorge explained the universe is a production of 781 00:40:31,920 --> 00:40:35,280 Speaker 1: I heart Radio or more podcast from my heart Radio. 782 00:40:35,440 --> 00:40:39,000 Speaker 1: Visit the I heart Radio app, Apple Podcasts, or wherever 783 00:40:39,120 --> 00:40:40,800 Speaker 1: you listen to your favorite shows.