1 00:00:03,040 --> 00:00:05,360 Speaker 1: Welcome to Scoot to Blow Your Mind production of My 2 00:00:05,480 --> 00:00:14,600 Speaker 1: Heart Radio. Hey you welcome to Stuff to Blow Your Mind. 3 00:00:14,640 --> 00:00:17,400 Speaker 1: My name is Robert Lamb and I'm Joe McCormick. And 4 00:00:17,480 --> 00:00:20,280 Speaker 1: today we have got a special treat for you. Returning 5 00:00:20,360 --> 00:00:24,360 Speaker 1: champion previous guests to the show, Daniel Whiteson of Daniel 6 00:00:24,400 --> 00:00:27,600 Speaker 1: and Jorge Explain the Universe. We are so privileged to 7 00:00:27,640 --> 00:00:30,400 Speaker 1: have Daniel join us again today. Daniel, say hi and 8 00:00:30,560 --> 00:00:33,960 Speaker 1: introduce yourself. For anybody who wasn't around last time, Hi guys, 9 00:00:34,000 --> 00:00:37,519 Speaker 1: thanks so much for having me on. Great to be back. Um. 10 00:00:37,520 --> 00:00:41,320 Speaker 1: I'm Daniel Whitson. I'm a professor of particle physics at 11 00:00:41,520 --> 00:00:44,839 Speaker 1: u c Irvine down here in southern California, and I'm 12 00:00:44,840 --> 00:00:47,879 Speaker 1: also the co host of the podcast Daniel and Jorge 13 00:00:47,920 --> 00:00:51,120 Speaker 1: Explain the Universe, a podcast with my good friend and 14 00:00:51,159 --> 00:00:54,440 Speaker 1: collaborator Jorge cham in which we talk all about the 15 00:00:54,560 --> 00:00:57,400 Speaker 1: craziness of the universe. We try to answer questions, We 16 00:00:57,440 --> 00:00:59,760 Speaker 1: try to share the wonder and the mystery of the 17 00:00:59,800 --> 00:01:02,480 Speaker 1: uni verse in a way that makes it accessible and 18 00:01:02,520 --> 00:01:05,080 Speaker 1: hopefully a little bit fun. Well, we really appreciate you 19 00:01:05,160 --> 00:01:08,280 Speaker 1: joining us today, Daniel. So I wanted to invite you 20 00:01:08,319 --> 00:01:11,800 Speaker 1: onto stuff to blow your mind today to talk about space. 21 00:01:11,959 --> 00:01:14,880 Speaker 1: This is actually a subject I've I've wanted to tackle 22 00:01:14,920 --> 00:01:18,200 Speaker 1: on the show for a while with uh, the unifying 23 00:01:18,280 --> 00:01:21,840 Speaker 1: question of what is space? Why is there such a 24 00:01:21,920 --> 00:01:25,000 Speaker 1: thing as the distance between the Earth and the Sun, 25 00:01:25,280 --> 00:01:28,800 Speaker 1: or between an atomic nucleus and the electron that orbits it. 26 00:01:29,480 --> 00:01:31,720 Speaker 1: Because I think a lot of the time when we 27 00:01:31,840 --> 00:01:36,240 Speaker 1: think about physical reality, we just immediately look past space 28 00:01:36,720 --> 00:01:39,560 Speaker 1: to the things that occupy it. We we assume space 29 00:01:39,600 --> 00:01:42,480 Speaker 1: as a kind of given, a de facto canvas on 30 00:01:42,520 --> 00:01:45,160 Speaker 1: which physics can be realized. But I wanted to think 31 00:01:45,160 --> 00:01:48,400 Speaker 1: about space itself. What is it? How does it exist? 32 00:01:48,480 --> 00:01:50,920 Speaker 1: Do we know anything about where it comes from and 33 00:01:51,320 --> 00:01:54,040 Speaker 1: where it's going? So maybe the easiest way to start 34 00:01:54,080 --> 00:01:56,600 Speaker 1: off today would be to to get as simple as 35 00:01:56,640 --> 00:01:59,840 Speaker 1: we can so in simplest terms in a sentence, if 36 00:01:59,840 --> 00:02:03,680 Speaker 1: you could do it, how would a physicist define space? 37 00:02:05,360 --> 00:02:08,079 Speaker 1: While all of space in one sentence? That is a 38 00:02:08,120 --> 00:02:11,360 Speaker 1: pretty tall order, you know, I have to say, to 39 00:02:11,400 --> 00:02:13,240 Speaker 1: be honest, I'd have to say, we really have no 40 00:02:13,400 --> 00:02:16,760 Speaker 1: idea what space is. I mean, I think it's wonderful 41 00:02:17,120 --> 00:02:20,480 Speaker 1: that you're asking this question. It's the kind of question 42 00:02:20,560 --> 00:02:23,400 Speaker 1: that it takes like a sort of maturity of science 43 00:02:23,400 --> 00:02:27,400 Speaker 1: and philosophy to even understand why the question is interesting 44 00:02:27,600 --> 00:02:31,000 Speaker 1: and important. You know. It's like it's like we're have 45 00:02:31,120 --> 00:02:35,120 Speaker 1: been fish scientists for a thousand years swimming through this fluid, 46 00:02:35,520 --> 00:02:40,160 Speaker 1: and then only recently have realized that it's it's something fascinating, 47 00:02:40,200 --> 00:02:42,960 Speaker 1: something to study, something that has property, something can do 48 00:02:43,120 --> 00:02:46,120 Speaker 1: weird things. And so it's a it's a deep and 49 00:02:46,160 --> 00:02:48,720 Speaker 1: important question, you know. And and just to digress a 50 00:02:48,760 --> 00:02:51,640 Speaker 1: tiny bit more like it makes me wonder how many 51 00:02:51,760 --> 00:02:55,560 Speaker 1: other crazy basic questions we aren't even asking because we 52 00:02:55,600 --> 00:02:58,560 Speaker 1: don't realize how rich the topic is, you know. So 53 00:02:58,600 --> 00:03:00,680 Speaker 1: I feel sort of privilege that we're at this moment 54 00:03:00,720 --> 00:03:03,800 Speaker 1: in science when we can ask this question what is 55 00:03:03,880 --> 00:03:07,919 Speaker 1: space and understand that it is an important question? Alright, 56 00:03:07,960 --> 00:03:11,959 Speaker 1: So I totally dodged your question there, But I could 57 00:03:11,960 --> 00:03:15,240 Speaker 1: try to give a one sentence answer if if you'd like, sure, 58 00:03:15,280 --> 00:03:17,600 Speaker 1: we'll start simple and then and then we'll get more 59 00:03:17,639 --> 00:03:20,800 Speaker 1: into the nuances here. All right, Well, a simple answer 60 00:03:20,840 --> 00:03:25,480 Speaker 1: to what is space? Is that? Oh man? I mean 61 00:03:25,520 --> 00:03:29,000 Speaker 1: I could try to maybe impossible, um, I'd say the 62 00:03:29,040 --> 00:03:33,079 Speaker 1: simplest description I could give for what space is is 63 00:03:33,680 --> 00:03:38,840 Speaker 1: something which has various properties. We've discovered it can contain 64 00:03:38,960 --> 00:03:43,640 Speaker 1: quantum fields, it can expand, and it has relationships to 65 00:03:43,760 --> 00:03:46,560 Speaker 1: other parts of space. And so that's more a description 66 00:03:46,600 --> 00:03:50,200 Speaker 1: of like what we've what we've observed about space. It's 67 00:03:50,240 --> 00:03:53,080 Speaker 1: not really an inherent understanding of what it is because 68 00:03:53,120 --> 00:03:56,240 Speaker 1: we don't have that understanding. Well, maybe this brings me 69 00:03:56,360 --> 00:03:58,880 Speaker 1: to a question I wanted to ask later on. But 70 00:04:00,080 --> 00:04:02,320 Speaker 1: if there is no good answer to this, it can 71 00:04:02,360 --> 00:04:04,280 Speaker 1: help ground us as we go forward. So I wanted 72 00:04:04,280 --> 00:04:06,960 Speaker 1: to ask, is there such a thing as even a 73 00:04:07,080 --> 00:04:13,520 Speaker 1: hypothetical physics without space? Does all physics assume space? And 74 00:04:13,600 --> 00:04:17,520 Speaker 1: can we imagine, say a possible world that exists but 75 00:04:17,720 --> 00:04:21,520 Speaker 1: does not contain space, or is that just inconceivable? Now? 76 00:04:21,640 --> 00:04:24,280 Speaker 1: I think that all physics that we do assume space, 77 00:04:24,360 --> 00:04:26,760 Speaker 1: Like all of our modern theories, the standard model and 78 00:04:26,839 --> 00:04:30,719 Speaker 1: quantum field theory, they all operate in some space. And 79 00:04:30,760 --> 00:04:33,120 Speaker 1: there are different kinds of theories that we have, and 80 00:04:33,200 --> 00:04:36,040 Speaker 1: some of those make different assumptions for what that space is. 81 00:04:36,520 --> 00:04:39,600 Speaker 1: Like quantum field theory, you write down with the spaces 82 00:04:39,600 --> 00:04:42,919 Speaker 1: in advance. You say I'm gonna assume space. You know 83 00:04:43,080 --> 00:04:45,920 Speaker 1: is three dimensions and extents in all in all these directions, 84 00:04:46,120 --> 00:04:47,840 Speaker 1: and then I'm going to talk about the fields that 85 00:04:47,880 --> 00:04:52,040 Speaker 1: are in that space. Other theories like general relativity. Space 86 00:04:52,120 --> 00:04:54,039 Speaker 1: is a part of what you're sort of trying to 87 00:04:54,080 --> 00:04:56,960 Speaker 1: get at. It's not like the backdrop. It's the thing 88 00:04:57,000 --> 00:04:59,960 Speaker 1: you solve for. You say, if I have this configuration, 89 00:05:00,040 --> 00:05:03,000 Speaker 1: then what does the space look like? But they all 90 00:05:03,040 --> 00:05:07,840 Speaker 1: assume space. I mean space gives you a relationship between stuff, right, 91 00:05:07,960 --> 00:05:10,039 Speaker 1: tells you this is here and this is not here. 92 00:05:10,680 --> 00:05:12,440 Speaker 1: And in the end, all of our theories are trying 93 00:05:12,440 --> 00:05:14,520 Speaker 1: to understand the world we live in, and everything we 94 00:05:14,560 --> 00:05:17,599 Speaker 1: live in has space. So it's pretty hard to grapple 95 00:05:17,680 --> 00:05:22,680 Speaker 1: with a non spatial theories or non spatial physics. So yeah, 96 00:05:22,720 --> 00:05:25,560 Speaker 1: I would say that we need space, okay, But so 97 00:05:25,600 --> 00:05:27,520 Speaker 1: if we could come at it from the exact opposite 98 00:05:27,520 --> 00:05:30,320 Speaker 1: angle you think, you you couldn't really have a physics 99 00:05:30,400 --> 00:05:34,600 Speaker 1: without space. Could you have a universe full of space 100 00:05:34,760 --> 00:05:38,480 Speaker 1: with no matter of energy in it? Could space exist 101 00:05:38,600 --> 00:05:43,080 Speaker 1: without any contents? Could space exists without any contents in it? Yeah? 102 00:05:43,080 --> 00:05:46,520 Speaker 1: That is an awesome question, and it's fascinating because we 103 00:05:46,600 --> 00:05:50,080 Speaker 1: have two theories of physics right now, quantum mechanics and 104 00:05:50,200 --> 00:05:55,080 Speaker 1: general relativity, and they're both awesome achievements, staggering insights into 105 00:05:55,120 --> 00:05:57,600 Speaker 1: the way the universe works, and they give different answers 106 00:05:57,640 --> 00:06:02,520 Speaker 1: to this question. Right, So general activity um is Einstein's theory. 107 00:06:02,839 --> 00:06:04,680 Speaker 1: And he has a bunch of equations. Let's say, what 108 00:06:04,720 --> 00:06:06,920 Speaker 1: the universe look like depending what you put in it, 109 00:06:07,240 --> 00:06:09,279 Speaker 1: and he has and one of the and it's really 110 00:06:09,320 --> 00:06:11,640 Speaker 1: hard to solve, like, there's very few ways you can 111 00:06:11,680 --> 00:06:14,520 Speaker 1: actually solve these equations. One of the very few ways 112 00:06:14,520 --> 00:06:16,760 Speaker 1: you actually can get an answer out is what they 113 00:06:16,800 --> 00:06:19,839 Speaker 1: call the vacuum solution, like to say, assume there's nothing, 114 00:06:20,400 --> 00:06:22,279 Speaker 1: then what does the universe look like? If there's nothing 115 00:06:22,320 --> 00:06:25,880 Speaker 1: in it? All? Right? Einstein can solve that problem quantum 116 00:06:25,920 --> 00:06:28,799 Speaker 1: field theory. Though, quantum field theory says, hold on a second, 117 00:06:29,279 --> 00:06:32,279 Speaker 1: um space is filled with all these quantum fields and 118 00:06:32,400 --> 00:06:34,680 Speaker 1: particles and matter and all the stuff that you make 119 00:06:34,720 --> 00:06:38,200 Speaker 1: me and you are just like excited states of these fields. 120 00:06:38,320 --> 00:06:41,360 Speaker 1: So when you look at an electron, it's not a particle, 121 00:06:41,400 --> 00:06:44,160 Speaker 1: it's not a wave. It's a little ripple in some 122 00:06:44,320 --> 00:06:47,760 Speaker 1: field which is not in space. It's part of space. 123 00:06:48,320 --> 00:06:50,680 Speaker 1: So if all these fields. You have the electron field, 124 00:06:50,720 --> 00:06:53,760 Speaker 1: the electromagnetic field, all the fields associated with each of 125 00:06:53,800 --> 00:06:55,880 Speaker 1: the forces. As lots of them. We can talk about 126 00:06:55,920 --> 00:06:59,400 Speaker 1: them later if you'd like. But some of them never 127 00:06:59,520 --> 00:07:03,640 Speaker 1: relax completely. Some of them are always have some energy 128 00:07:03,680 --> 00:07:06,760 Speaker 1: in them, for example, the Higgs field. The Higgs field 129 00:07:06,839 --> 00:07:09,240 Speaker 1: is in every part of space, and it's always got 130 00:07:09,279 --> 00:07:12,760 Speaker 1: some built intention to it, and that means that there's 131 00:07:12,840 --> 00:07:16,040 Speaker 1: energy in every part of space. So quantum field theory says, no, 132 00:07:16,160 --> 00:07:18,840 Speaker 1: you can't have space without some energy in it. There's 133 00:07:18,840 --> 00:07:22,720 Speaker 1: some inherent energy to space, where the general relativity says, 134 00:07:23,040 --> 00:07:25,920 Speaker 1: I could totally imagine it. And we don't know which 135 00:07:26,000 --> 00:07:29,160 Speaker 1: theory is the fundamental, true theory of the universe. If 136 00:07:29,200 --> 00:07:31,840 Speaker 1: either one, we can't seem to make them play together 137 00:07:31,960 --> 00:07:34,680 Speaker 1: very well. And so this question really goes to the 138 00:07:34,720 --> 00:07:37,880 Speaker 1: heart of the nature of reality itself. It's fascinating. It's 139 00:07:37,880 --> 00:07:40,760 Speaker 1: the kind of thing that in five years physicists will 140 00:07:40,760 --> 00:07:42,760 Speaker 1: know the answer to and look back at us and 141 00:07:42,760 --> 00:07:46,080 Speaker 1: be like, oh, man, those people didn't understand anything about 142 00:07:46,120 --> 00:07:48,000 Speaker 1: the nature of the universe they were living in, right, 143 00:07:48,120 --> 00:07:50,440 Speaker 1: What a bunch of cave men and cave women like 144 00:07:50,680 --> 00:07:53,280 Speaker 1: they were subjignary misses. So I love that idea about 145 00:07:53,360 --> 00:07:55,840 Speaker 1: quantum field theory. And if I understand this right, you're 146 00:07:55,840 --> 00:07:59,600 Speaker 1: saying that under the assumptions of quantum field theory, you 147 00:07:59,600 --> 00:08:01,560 Speaker 1: could have a big block of space, and even if 148 00:08:01,560 --> 00:08:04,040 Speaker 1: you were able to clear everything out of it, clear 149 00:08:04,040 --> 00:08:06,600 Speaker 1: out all the hydrogen particles, clear out all the dust, 150 00:08:06,680 --> 00:08:10,560 Speaker 1: so there's no matter left in it, you'd still you 151 00:08:10,640 --> 00:08:14,400 Speaker 1: still really wouldn't have an empty void. Is that correct? 152 00:08:14,800 --> 00:08:18,360 Speaker 1: That's right. Every unit of space comes with energy built 153 00:08:18,400 --> 00:08:21,600 Speaker 1: in it comes from the factory with energy already in it, 154 00:08:22,200 --> 00:08:26,240 Speaker 1: and um and and lots of those fields cannot cannot relax. 155 00:08:26,240 --> 00:08:28,440 Speaker 1: The Higgs field is one example, but many of these 156 00:08:28,480 --> 00:08:31,480 Speaker 1: fields cannot relax all the way down to zero. And 157 00:08:31,520 --> 00:08:34,600 Speaker 1: so it's impossible, according to these quantum theories, to have 158 00:08:34,720 --> 00:08:37,760 Speaker 1: space with no energy density in it at all. And 159 00:08:37,800 --> 00:08:40,000 Speaker 1: that means and that's stuff, right, All stuff is is 160 00:08:40,040 --> 00:08:42,120 Speaker 1: some kind of energy, like the matter that makes it 161 00:08:42,200 --> 00:08:45,080 Speaker 1: me and you. That's just a form of energy. So 162 00:08:45,160 --> 00:08:47,360 Speaker 1: to say that this space has energy in it really 163 00:08:47,400 --> 00:08:50,600 Speaker 1: means it's not empty. So what you're describing space as 164 00:08:51,120 --> 00:08:53,840 Speaker 1: really goes against a lot of our intuitions, where you know, 165 00:08:54,080 --> 00:08:56,719 Speaker 1: I think the standard understanding of empty space what's out 166 00:08:56,760 --> 00:08:58,800 Speaker 1: there beyond Earth, you know, even if you could clear 167 00:08:58,800 --> 00:09:01,800 Speaker 1: all the hydrogen and dust and everything out of it, 168 00:09:01,840 --> 00:09:05,440 Speaker 1: is that it's just this empty relationship between two points. 169 00:09:05,480 --> 00:09:08,600 Speaker 1: But you mentioned, of course, the the idea that there, 170 00:09:08,600 --> 00:09:11,679 Speaker 1: you know, quantum fields that can be excited and can 171 00:09:11,679 --> 00:09:14,360 Speaker 1: give birth to particles and stuff. Well, I might be 172 00:09:14,360 --> 00:09:17,520 Speaker 1: putting words in your mouth. There is that correct though. Yeah, okay, 173 00:09:18,120 --> 00:09:21,160 Speaker 1: but earlier you mentioned also that it has other properties, 174 00:09:21,200 --> 00:09:23,920 Speaker 1: So it sounds like you're saying space really is a thing. 175 00:09:24,120 --> 00:09:28,199 Speaker 1: It's almost like a substance of a kind. Yes, space 176 00:09:28,320 --> 00:09:32,160 Speaker 1: is a goo. Right. We first imagine space sort of 177 00:09:32,200 --> 00:09:34,480 Speaker 1: as a place to hold our ideas, right where like 178 00:09:34,920 --> 00:09:37,880 Speaker 1: maybe when you think space and you think a deep space, 179 00:09:37,920 --> 00:09:41,360 Speaker 1: you imagine some like glowing x y z axes that 180 00:09:41,480 --> 00:09:44,080 Speaker 1: used to like the backdrop on which maybe your calculations 181 00:09:44,120 --> 00:09:47,400 Speaker 1: take place or your spaceship flies through or whatever sort of. 182 00:09:47,840 --> 00:09:51,920 Speaker 1: But they're like mental metrics we use to understand where 183 00:09:51,960 --> 00:09:54,720 Speaker 1: things are. That sort of the initial idea of space. 184 00:09:55,040 --> 00:09:57,120 Speaker 1: But then it turns out the space can do things 185 00:09:57,360 --> 00:10:01,080 Speaker 1: that are inconsistent with that, right, Like space can ripple 186 00:10:01,679 --> 00:10:05,280 Speaker 1: we've seen gravitational waves. When black holes orbit each other 187 00:10:05,320 --> 00:10:08,400 Speaker 1: and eventually collide or other things happen, they create these 188 00:10:08,480 --> 00:10:13,040 Speaker 1: ripples in space itself. These ripples, they're space getting stretched 189 00:10:13,240 --> 00:10:17,520 Speaker 1: and space getting contracted, right, squeezing and shrinking and then 190 00:10:17,559 --> 00:10:20,200 Speaker 1: expanding again, and very very very small, which is why 191 00:10:20,240 --> 00:10:22,719 Speaker 1: they were hard to discover. But yes, we've discovered that 192 00:10:22,760 --> 00:10:27,120 Speaker 1: space can do things. So it can ripple, it can expand, right, 193 00:10:27,160 --> 00:10:30,480 Speaker 1: We've talked about the expansion of the universe, the universe 194 00:10:30,640 --> 00:10:34,640 Speaker 1: expanding its first moments, and it's continuing to expand. In addition, 195 00:10:34,720 --> 00:10:38,000 Speaker 1: space can bend. Maybe the most familiar example is understanding 196 00:10:38,040 --> 00:10:43,240 Speaker 1: gravity as distortions in space by having mass nearby and 197 00:10:43,240 --> 00:10:46,520 Speaker 1: and so space can do all these things that nothingness 198 00:10:46,559 --> 00:10:49,360 Speaker 1: cannot do, that a backdrop cannot do. You can't just 199 00:10:49,400 --> 00:10:52,400 Speaker 1: think of spaces like the theater of the universe. It's 200 00:10:52,440 --> 00:10:55,760 Speaker 1: a weird dynamical thing in itself. Yeah, I think in 201 00:10:55,800 --> 00:10:58,240 Speaker 1: general our listeners are going to be more familiar with 202 00:10:58,240 --> 00:11:01,120 Speaker 1: the idea that space can can bend in accordance with 203 00:11:01,160 --> 00:11:03,640 Speaker 1: general relativity. There's a big object, you know, and that 204 00:11:03,800 --> 00:11:07,600 Speaker 1: creates curvature, and in spacetime it's a little bit harder 205 00:11:07,600 --> 00:11:09,960 Speaker 1: to picture exactly what's happening with the first thing you 206 00:11:10,000 --> 00:11:12,720 Speaker 1: mentioned with the ripples through spacetime. So that's something that 207 00:11:12,720 --> 00:11:16,520 Speaker 1: would be like, that's like how we detected gravitational waves, right, 208 00:11:16,679 --> 00:11:20,320 Speaker 1: is that correct? Um? So what what exactly is happening 209 00:11:20,360 --> 00:11:23,880 Speaker 1: when a ripple goes through space? Like? How do how 210 00:11:23,880 --> 00:11:27,439 Speaker 1: do you measure that? What? What is that in the moment? Right? Well, 211 00:11:27,840 --> 00:11:31,040 Speaker 1: you know, a ripple through space is information propagating through 212 00:11:31,040 --> 00:11:34,040 Speaker 1: the gravitational field. Something that's very important that came out 213 00:11:34,080 --> 00:11:36,840 Speaker 1: of general relativity that we didn't have with Newton's gravity 214 00:11:37,160 --> 00:11:41,160 Speaker 1: is the concept that information takes time to move gravitationally. 215 00:11:41,520 --> 00:11:45,120 Speaker 1: Like if the Sun disappeared, would we feel the Sun's 216 00:11:45,200 --> 00:11:49,320 Speaker 1: gravity instantly disappear or would it take a moment? Turns 217 00:11:49,320 --> 00:11:52,720 Speaker 1: out Newton says it would go away instantly. Einstein says, no, 218 00:11:52,920 --> 00:11:55,720 Speaker 1: you wouldn't even notice for eight minutes because the gravity 219 00:11:55,800 --> 00:11:58,840 Speaker 1: from the Sun would take The information about the Sun 220 00:11:58,880 --> 00:12:01,840 Speaker 1: being gone would take eight minutes to get here gravitationally, 221 00:12:02,679 --> 00:12:06,839 Speaker 1: And so that's propagation of information. And so gravitational wave 222 00:12:07,200 --> 00:12:10,400 Speaker 1: is a special form of that. Say you're familiar with 223 00:12:10,720 --> 00:12:14,079 Speaker 1: the concept of like putting a mass and that deforms space. 224 00:12:14,200 --> 00:12:16,160 Speaker 1: We'll imagine you put a mass in space, and then 225 00:12:16,200 --> 00:12:17,680 Speaker 1: you take it away, and you put it in space, 226 00:12:17,720 --> 00:12:19,240 Speaker 1: and you take it away, and you put in space 227 00:12:19,280 --> 00:12:21,480 Speaker 1: and you take it away. What's going to happen, Well, 228 00:12:21,520 --> 00:12:23,040 Speaker 1: you know it's not gonna be very pleasant for the 229 00:12:23,040 --> 00:12:25,800 Speaker 1: occupants of your space. They're gonna get jerked around, right, 230 00:12:25,840 --> 00:12:28,360 Speaker 1: It's back and forth and back and forth. And that's 231 00:12:28,360 --> 00:12:31,079 Speaker 1: sort of a more dramatic version of what happens when 232 00:12:31,120 --> 00:12:35,520 Speaker 1: two black holes orbit each other. Is they're creating ripples 233 00:12:35,600 --> 00:12:39,840 Speaker 1: in this gravitational field, and you feel those as stretching 234 00:12:39,840 --> 00:12:42,680 Speaker 1: and squeezing of space itself. And we measured that here 235 00:12:42,679 --> 00:12:47,040 Speaker 1: on Earth by having really long rods essentially and watching 236 00:12:47,080 --> 00:12:50,760 Speaker 1: them shrink and expand shrink and expand. With those north 237 00:12:50,880 --> 00:12:52,800 Speaker 1: there would be like lasers that you would use to 238 00:12:52,960 --> 00:12:56,320 Speaker 1: measure that. Yeah, the practical way you measure a very 239 00:12:56,400 --> 00:12:59,079 Speaker 1: small change in the length of a long rod is 240 00:12:59,120 --> 00:13:01,199 Speaker 1: that you don't actually of the physical rods. That was 241 00:13:01,240 --> 00:13:03,320 Speaker 1: the first thing they tried, actually did that here, you see, 242 00:13:03,320 --> 00:13:05,960 Speaker 1: I Jo Webber did that, and it's because he had 243 00:13:06,000 --> 00:13:08,200 Speaker 1: no idea like maybe this is easy to spot right, 244 00:13:08,320 --> 00:13:10,240 Speaker 1: let's just build a big block of metal and see 245 00:13:10,240 --> 00:13:12,520 Speaker 1: if its shrinks and expands. I was gonna say, what 246 00:13:12,600 --> 00:13:14,679 Speaker 1: was it made out of? Yeah, it's just a big 247 00:13:14,800 --> 00:13:18,480 Speaker 1: cylinder of metal. Um. But nowadays they're miles long and 248 00:13:18,600 --> 00:13:21,199 Speaker 1: their laser and they use lasers to measure the length 249 00:13:21,280 --> 00:13:25,400 Speaker 1: between two isolated mirrors. And I think that the biggest 250 00:13:25,440 --> 00:13:30,280 Speaker 1: misconception people have about space being bent by mass is 251 00:13:30,280 --> 00:13:32,960 Speaker 1: that they're used to this rubber sheet analogy where you 252 00:13:33,000 --> 00:13:34,800 Speaker 1: have like a big rubber sheet and you put a 253 00:13:34,840 --> 00:13:37,439 Speaker 1: bowling ball in it and it bends space. And the 254 00:13:37,440 --> 00:13:39,959 Speaker 1: bowling ball is supposed to represent the sun and the 255 00:13:40,040 --> 00:13:43,439 Speaker 1: rubber sheet is supposed to represent space. And that's helpful 256 00:13:43,520 --> 00:13:45,400 Speaker 1: up to a point because it gets you to think 257 00:13:45,440 --> 00:13:48,880 Speaker 1: about space being bent instead of flat. But it's also 258 00:13:48,920 --> 00:13:52,240 Speaker 1: I think confusing. And the way it's confusing is that 259 00:13:52,400 --> 00:13:54,880 Speaker 1: it's bending in some sort of third dimension, right, and 260 00:13:54,920 --> 00:13:58,360 Speaker 1: that analogy space the universe is two D and you 261 00:13:58,440 --> 00:14:00,840 Speaker 1: put some object in it and it bends in some 262 00:14:01,000 --> 00:14:04,680 Speaker 1: third dimension. But our space it's three D. First of all, 263 00:14:05,040 --> 00:14:06,840 Speaker 1: when you put a mass in it, it doesn't bend 264 00:14:06,920 --> 00:14:10,280 Speaker 1: in some fourth dimension. It's not like our space is 265 00:14:10,320 --> 00:14:12,960 Speaker 1: embedded in some higher dimensional space and then it gets 266 00:14:13,000 --> 00:14:16,600 Speaker 1: bent in fourth dimension. It's an intrinsic bending, not an 267 00:14:16,640 --> 00:14:19,440 Speaker 1: extrinsic It's not like there's somebody out there with a 268 00:14:19,520 --> 00:14:22,200 Speaker 1: true set of rulers in four D space and they're 269 00:14:22,280 --> 00:14:26,640 Speaker 1: noticing our space being bent. It's an intrinsic bending, which 270 00:14:26,680 --> 00:14:30,640 Speaker 1: means it just changes the relationship between points in space. 271 00:14:31,240 --> 00:14:33,960 Speaker 1: Right it says, Okay, now that space, that bit of 272 00:14:34,000 --> 00:14:36,000 Speaker 1: space is closer and this bit of a space is 273 00:14:36,040 --> 00:14:39,000 Speaker 1: further away. Wow. So I've never thought of it that way. So, 274 00:14:39,160 --> 00:14:41,600 Speaker 1: so you're saying that the gravitational influence of a large 275 00:14:41,640 --> 00:14:45,840 Speaker 1: object like a star is in some literal sense shortening 276 00:14:45,920 --> 00:14:49,160 Speaker 1: the distance between points of space as you get closer 277 00:14:49,200 --> 00:14:54,000 Speaker 1: to it. Absolutely. You know, massless particles like photons travel 278 00:14:54,360 --> 00:14:58,440 Speaker 1: not in straight lines. They travel along geodesics, which means 279 00:14:58,480 --> 00:15:01,840 Speaker 1: the shortest path through curved space. Now out in the 280 00:15:01,840 --> 00:15:04,640 Speaker 1: middle of nowhere, there's no mass anywhere that happens to 281 00:15:04,640 --> 00:15:06,560 Speaker 1: be a straight line. That's why it seems like photons 282 00:15:06,600 --> 00:15:10,080 Speaker 1: travel straight. But photons can also be bent by the sun. 283 00:15:10,160 --> 00:15:13,000 Speaker 1: How does that happen? Photons have no mass, right, Well, 284 00:15:13,040 --> 00:15:15,840 Speaker 1: the the Sun is changing the shape of space, so 285 00:15:15,920 --> 00:15:18,400 Speaker 1: that the shortest path from A to B is no 286 00:15:18,520 --> 00:15:22,000 Speaker 1: longer what we would consider a straight line. It's a geodesic. 287 00:15:22,040 --> 00:15:25,960 Speaker 1: It's the shortest path. And so general relativity and mass 288 00:15:26,080 --> 00:15:30,680 Speaker 1: changes the relationship between space between here and there, and um, 289 00:15:30,720 --> 00:15:32,800 Speaker 1: that's what we maybe you hear people talk about like 290 00:15:32,840 --> 00:15:36,040 Speaker 1: the spacetime metric that relates like how bits of space 291 00:15:36,080 --> 00:15:39,280 Speaker 1: are connected. So this is sort of the biggest conceptual 292 00:15:39,320 --> 00:15:41,880 Speaker 1: leap to make from the rubber sheet analogy to our 293 00:15:41,920 --> 00:15:45,840 Speaker 1: actual three D space, which is that it's an intrinsic bending. 294 00:15:45,840 --> 00:15:48,800 Speaker 1: It's a relationship between points in space, and that's what 295 00:15:48,840 --> 00:15:51,840 Speaker 1: a gravitational wave is doing. Also, it's a ripple in 296 00:15:51,880 --> 00:15:54,840 Speaker 1: this metric as it passes through space, and it's saying, oh, 297 00:15:54,880 --> 00:15:57,400 Speaker 1: these things are now closer together, now the further apart. 298 00:15:57,960 --> 00:16:01,120 Speaker 1: Like you can change the distance, but weeen two things 299 00:16:01,160 --> 00:16:05,640 Speaker 1: without those things moving relative to each other, right, because 300 00:16:05,680 --> 00:16:09,000 Speaker 1: you change the relative distances. Well, it almost makes me 301 00:16:09,040 --> 00:16:12,560 Speaker 1: think in terms of how this is communicated to non experts, 302 00:16:12,560 --> 00:16:15,160 Speaker 1: that would maybe be better to not use terms like 303 00:16:15,240 --> 00:16:18,320 Speaker 1: bending of space and maybe more like compressing or squeezing 304 00:16:18,320 --> 00:16:21,800 Speaker 1: of space. Yeah, but space can also be expanded, right, 305 00:16:21,880 --> 00:16:24,160 Speaker 1: like what we're seeing in the universe right now is 306 00:16:24,200 --> 00:16:27,200 Speaker 1: that space is expanding, which is crazy. It's like something 307 00:16:27,200 --> 00:16:31,320 Speaker 1: out there is manufacturing new units of space all the time. 308 00:16:31,320 --> 00:16:35,040 Speaker 1: It's filling the universe with new space. Like that's that's 309 00:16:35,040 --> 00:16:36,720 Speaker 1: the hardest thing for me to get my mind around. 310 00:16:36,760 --> 00:16:38,760 Speaker 1: It's like where this new space is coming from, what 311 00:16:38,840 --> 00:16:41,000 Speaker 1: it means to make new space? And are you making 312 00:16:41,160 --> 00:16:44,520 Speaker 1: units of new space? There's space continuous and smooth and like, man, 313 00:16:44,560 --> 00:16:46,800 Speaker 1: there's so many questions. Oh well, I want to talk 314 00:16:46,800 --> 00:16:48,440 Speaker 1: about that. Maybe we should take a quick break and 315 00:16:48,440 --> 00:16:50,920 Speaker 1: then when we come back we can explore the expansion 316 00:16:50,920 --> 00:16:56,840 Speaker 1: of space. Sounds good than all? Right, we're back. We're 317 00:16:56,840 --> 00:17:01,000 Speaker 1: talking with Daniel Whitson about space, the nature of space. 318 00:17:01,400 --> 00:17:03,720 Speaker 1: That's right. So before we went to the break, Daniel, 319 00:17:03,800 --> 00:17:06,399 Speaker 1: you just introduced the idea of the expansion of space. 320 00:17:06,400 --> 00:17:08,760 Speaker 1: As we've we've been talking about the properties of space 321 00:17:08,800 --> 00:17:12,199 Speaker 1: as a as a thing and not just an emptiness. Uh. 322 00:17:12,240 --> 00:17:14,200 Speaker 1: And so of course we know one of the things 323 00:17:14,240 --> 00:17:18,159 Speaker 1: that space is doing is that it's expanding. Uh. I 324 00:17:18,200 --> 00:17:20,480 Speaker 1: think we all know now that the universe as a 325 00:17:20,520 --> 00:17:24,080 Speaker 1: whole is expanding and maybe expanding at an accelerating rate. 326 00:17:24,119 --> 00:17:26,199 Speaker 1: If I've got that writing, comment on that in a second. 327 00:17:26,760 --> 00:17:31,040 Speaker 1: What exactly does it mean for space to expand? Because 328 00:17:31,520 --> 00:17:34,360 Speaker 1: I think from an intuitive level, people might think, well, 329 00:17:34,800 --> 00:17:38,320 Speaker 1: I don't notice space expanding, Like I don't notice it 330 00:17:38,359 --> 00:17:42,320 Speaker 1: doesn't seem like the space in between the molecules in 331 00:17:42,359 --> 00:17:46,000 Speaker 1: my body is expanding. So so is space in general 332 00:17:46,080 --> 00:17:50,320 Speaker 1: expanding or is it just say, the distance between galaxies 333 00:17:50,400 --> 00:17:53,600 Speaker 1: is expanding. What form does that expansion take? Yeah, it's 334 00:17:53,600 --> 00:17:56,040 Speaker 1: a great question. I love the intuition there. You know. 335 00:17:56,119 --> 00:17:58,280 Speaker 1: The idea is like this thing is supposed to be 336 00:17:58,359 --> 00:18:01,160 Speaker 1: happening everywhere in the universe. Kind of sort of reconcile 337 00:18:01,280 --> 00:18:03,960 Speaker 1: that with my experience. Can I see that happening around me? 338 00:18:04,240 --> 00:18:06,240 Speaker 1: And you know, like a few hundred years ago, that 339 00:18:06,280 --> 00:18:08,800 Speaker 1: was a big conceptual leap to say like the rules 340 00:18:08,800 --> 00:18:11,320 Speaker 1: of the universe should also being applied here. Um. So 341 00:18:11,520 --> 00:18:14,200 Speaker 1: it's a great question. And and the short answer is 342 00:18:14,240 --> 00:18:17,479 Speaker 1: that space is expanding everywhere, Like every unit of space 343 00:18:17,680 --> 00:18:20,120 Speaker 1: is the same. It's homogeneous as far as we understand. 344 00:18:20,280 --> 00:18:22,760 Speaker 1: There's no difference to this chunk of space and a 345 00:18:22,840 --> 00:18:26,520 Speaker 1: chunk of space out there in the deepest voids between galaxies. 346 00:18:26,560 --> 00:18:28,040 Speaker 1: They're all the same from the point of view of 347 00:18:28,080 --> 00:18:30,880 Speaker 1: the universe, and they're all expanding, which means they're all 348 00:18:30,920 --> 00:18:34,600 Speaker 1: creating new space. But that's not the only thing happening, right. 349 00:18:35,119 --> 00:18:38,280 Speaker 1: You are made of a mesh of atoms that are 350 00:18:38,320 --> 00:18:41,879 Speaker 1: held together with pretty strong bonds, and this expansion of 351 00:18:41,920 --> 00:18:45,959 Speaker 1: space is dramatic, but per unit of space, it's pretty small. 352 00:18:46,320 --> 00:18:48,200 Speaker 1: Like there's not a whole lot of space being made 353 00:18:48,240 --> 00:18:52,280 Speaker 1: between me and this microphone, for example. It adds up 354 00:18:52,400 --> 00:18:54,800 Speaker 1: when you get to like cosmic scales between me and 355 00:18:54,800 --> 00:18:57,240 Speaker 1: the galaxy, because there's a lot of space between us, 356 00:18:57,800 --> 00:19:00,320 Speaker 1: but here on the small scale, it's not very powerful, 357 00:19:00,400 --> 00:19:02,840 Speaker 1: so the bonds in my body are strong enough to 358 00:19:02,880 --> 00:19:05,879 Speaker 1: hold me together. The same thing said for you know 359 00:19:05,920 --> 00:19:08,320 Speaker 1: the reason why you're staying on Earth. You know, Earth 360 00:19:08,440 --> 00:19:10,880 Speaker 1: is holding you down because if it's gravity, that's enough 361 00:19:10,920 --> 00:19:14,200 Speaker 1: to overcome this expansion of space, and Earth is bound 362 00:19:14,200 --> 00:19:17,520 Speaker 1: gravitationally to the Sun for the same reason. The space 363 00:19:17,560 --> 00:19:21,040 Speaker 1: between us and the Sun is expanding, but the gravity 364 00:19:21,119 --> 00:19:23,840 Speaker 1: the Sun holds us there. It's like if you were 365 00:19:24,160 --> 00:19:26,840 Speaker 1: sliding away from somebody on an ice sheet, but they 366 00:19:26,840 --> 00:19:28,920 Speaker 1: had a rope around you, and so they were keeping 367 00:19:28,920 --> 00:19:31,800 Speaker 1: you at a fixed distance. Okay, so there are forces 368 00:19:31,880 --> 00:19:35,160 Speaker 1: within our bodies, holding our bodies together that are counteracting 369 00:19:35,200 --> 00:19:39,000 Speaker 1: that expansive force. But I'm trying to imagine what exact 370 00:19:39,080 --> 00:19:42,480 Speaker 1: form does that take. So does that mean that the say, 371 00:19:42,520 --> 00:19:45,360 Speaker 1: the bonds between the molecules and our body holding them 372 00:19:45,359 --> 00:19:49,359 Speaker 1: together actually prevent the space from expanding there so it 373 00:19:49,400 --> 00:19:52,040 Speaker 1: doesn't expand, or does the space somehow kind of roll 374 00:19:52,160 --> 00:19:56,240 Speaker 1: out beyond us without affecting our you know, our bodies 375 00:19:56,280 --> 00:19:59,240 Speaker 1: as it does. So you can't stop the expansion of space, 376 00:19:59,440 --> 00:20:02,200 Speaker 1: but you can't and keep your constant distance. If those 377 00:20:02,240 --> 00:20:04,800 Speaker 1: bonds were deleted, then all the items would sort of 378 00:20:04,880 --> 00:20:07,479 Speaker 1: drift further and further apart, but instead you have these 379 00:20:07,520 --> 00:20:09,720 Speaker 1: bonds holding them together. And so it's more of that 380 00:20:09,840 --> 00:20:12,359 Speaker 1: the answers the latter, that space sort of rolls out 381 00:20:12,400 --> 00:20:16,960 Speaker 1: past you. So space is emanating from us at all times. Yeah, 382 00:20:17,000 --> 00:20:19,480 Speaker 1: it's sort of like we're in a pool of space 383 00:20:19,520 --> 00:20:22,240 Speaker 1: that's expanding larger and larger, and we're a smaller and 384 00:20:22,240 --> 00:20:25,119 Speaker 1: smaller dot inside of it. So as a result, you know, 385 00:20:25,119 --> 00:20:27,800 Speaker 1: the universe is getting getting more and more dilute, like 386 00:20:27,920 --> 00:20:32,000 Speaker 1: the matter energy density of the universe decreases with time 387 00:20:32,080 --> 00:20:34,480 Speaker 1: because there's no more stuff being created, but there is 388 00:20:34,520 --> 00:20:38,440 Speaker 1: more space being created all the time. And so that's 389 00:20:38,440 --> 00:20:41,200 Speaker 1: really like the way to think about the whole expansion 390 00:20:41,200 --> 00:20:43,560 Speaker 1: of the universe since the Big Bangs, that the universe 391 00:20:43,560 --> 00:20:46,520 Speaker 1: didn't start out small. It started out dense. It was 392 00:20:46,560 --> 00:20:49,720 Speaker 1: like compressed and hot and nasty and wet, and then 393 00:20:49,840 --> 00:20:52,760 Speaker 1: the Big Bang is just this rapid dilution of space 394 00:20:52,880 --> 00:20:56,440 Speaker 1: into something much more sparse, and then that's just continued. 395 00:20:56,640 --> 00:20:58,919 Speaker 1: The universe has just gotten more and more cold and 396 00:20:58,960 --> 00:21:01,960 Speaker 1: dilute and spread out as new spaces being created and 397 00:21:02,000 --> 00:21:05,480 Speaker 1: these little chunks of matter desperately clinging to each other 398 00:21:05,720 --> 00:21:09,000 Speaker 1: to avoid being totally isolated. And I think there's another 399 00:21:09,000 --> 00:21:10,760 Speaker 1: part of your question which I think is fascinating, is 400 00:21:10,800 --> 00:21:13,520 Speaker 1: like at what scale does that take over? Like you 401 00:21:13,560 --> 00:21:16,639 Speaker 1: hold yourself together, Yeah, the Earth holds onto you, the 402 00:21:16,680 --> 00:21:19,399 Speaker 1: Sun holds onto the Earth, the galaxy holds onto the 403 00:21:19,440 --> 00:21:22,439 Speaker 1: Sun and all the stars, and dark energy is probably 404 00:21:22,480 --> 00:21:26,239 Speaker 1: not going to rip apart our galaxy, and even the 405 00:21:26,280 --> 00:21:29,720 Speaker 1: neighboring galaxies like Andromeda is going to collide into us, 406 00:21:30,080 --> 00:21:32,399 Speaker 1: and the direct gravity these two galaxies are going to 407 00:21:32,880 --> 00:21:36,480 Speaker 1: smash them together, and the group of galaxies is mostly 408 00:21:36,520 --> 00:21:40,960 Speaker 1: gravitationally bound, and that's the biggest sort of gravitationally bound thing. 409 00:21:41,080 --> 00:21:45,200 Speaker 1: Beyond that, things are not tightly connected enough by gravity 410 00:21:45,240 --> 00:21:48,159 Speaker 1: to resist dark energy. And that's so it's these groups 411 00:21:48,160 --> 00:21:51,000 Speaker 1: of galaxies that are getting pushed apart and getting further 412 00:21:51,040 --> 00:21:53,720 Speaker 1: and further away because there's nothing really to resist the 413 00:21:54,200 --> 00:21:58,119 Speaker 1: dark energy push. Okay, So the reason then that you 414 00:21:58,160 --> 00:22:00,960 Speaker 1: would normally see the expansion of the universe expressed in 415 00:22:01,080 --> 00:22:04,159 Speaker 1: terms of like the separation of what galaxy clusters or 416 00:22:04,160 --> 00:22:06,840 Speaker 1: what it would be that that's where gravity is no 417 00:22:06,960 --> 00:22:11,200 Speaker 1: longer strong enough to hold back against it. And it's 418 00:22:11,240 --> 00:22:14,640 Speaker 1: not just the amount of distance, you know, causes the 419 00:22:14,760 --> 00:22:17,840 Speaker 1: uh causes all the expansion to add up there, That's right, 420 00:22:17,880 --> 00:22:20,239 Speaker 1: It's it's both things. I mean, the the amount of 421 00:22:20,280 --> 00:22:24,280 Speaker 1: distance makes it more dramatic, and the distance makes gravity weaker. 422 00:22:24,880 --> 00:22:27,080 Speaker 1: And so what you think which happens if you sort 423 00:22:27,080 --> 00:22:30,600 Speaker 1: of project the universe forward billions or trillions of years, 424 00:22:30,800 --> 00:22:34,399 Speaker 1: is that these gravitationally bound clusters continue to contract and 425 00:22:34,520 --> 00:22:37,000 Speaker 1: hold themselves together, but they get more and more distant 426 00:22:37,080 --> 00:22:40,840 Speaker 1: from everything else. So the future is is islands of 427 00:22:41,040 --> 00:22:45,760 Speaker 1: stuff separated by even more vast distances of space. It's interesting. 428 00:22:46,000 --> 00:22:49,160 Speaker 1: So all of this talk about space as a substance 429 00:22:49,280 --> 00:22:51,800 Speaker 1: and having all these properties that we can measure and 430 00:22:51,880 --> 00:22:54,040 Speaker 1: not just as a you know, uh, the void or 431 00:22:54,080 --> 00:22:57,960 Speaker 1: the distance between things is uh somehow on on one level, 432 00:22:58,240 --> 00:23:00,480 Speaker 1: kind of makes a lot of these like sci fi 433 00:23:00,560 --> 00:23:05,800 Speaker 1: plots where you manipulate space itself with technology seem more plausible. Robert, 434 00:23:05,800 --> 00:23:08,960 Speaker 1: I think you had some questions about this, maybe right, yeah, yeah, 435 00:23:08,960 --> 00:23:11,919 Speaker 1: this this got me thinking, you know about the expansion 436 00:23:11,920 --> 00:23:15,000 Speaker 1: explosive expansion. H Daniel, what do you make of the 437 00:23:15,080 --> 00:23:19,040 Speaker 1: notion that faster than light travel could essentially be achieved 438 00:23:19,119 --> 00:23:22,679 Speaker 1: by some manner of of work bubble manipulation moving the 439 00:23:22,720 --> 00:23:27,040 Speaker 1: space containing the ship rather than the ship through space alone. Oh, 440 00:23:27,080 --> 00:23:32,000 Speaker 1: I'm ready to invest in your work drive company for sure. UM. 441 00:23:32,040 --> 00:23:34,679 Speaker 1: I read a lot of science fiction, and um, I 442 00:23:34,720 --> 00:23:37,639 Speaker 1: love these ideas. And there's a lot of bolognay and 443 00:23:37,640 --> 00:23:40,399 Speaker 1: science fiction where they just like slap quantum mechanics on 444 00:23:40,480 --> 00:23:42,080 Speaker 1: a plot hole because they don't really know how to 445 00:23:42,119 --> 00:23:44,639 Speaker 1: think about it. But I give people a lot of 446 00:23:44,680 --> 00:23:47,520 Speaker 1: flexibility when it comes to space because we really don't 447 00:23:47,560 --> 00:23:50,399 Speaker 1: know what he can do. And there's a lot of 448 00:23:50,400 --> 00:23:53,199 Speaker 1: opportunities there for new ideas. And the one that you 449 00:23:53,280 --> 00:23:55,960 Speaker 1: mentioned I think is is a great um idea and 450 00:23:55,960 --> 00:23:58,840 Speaker 1: it's not just science fiction. I think it really could 451 00:23:58,880 --> 00:24:02,000 Speaker 1: be that we could develop a warp drive that that 452 00:24:02,119 --> 00:24:05,520 Speaker 1: gets us two distant stars. You know, there's one very 453 00:24:05,680 --> 00:24:08,679 Speaker 1: hard and fast rule about the universe, which is you 454 00:24:08,720 --> 00:24:11,960 Speaker 1: cannot move through space faster than the speed of light. 455 00:24:12,400 --> 00:24:14,280 Speaker 1: But you've gotta be a bit of a lawyer about it, right, 456 00:24:14,280 --> 00:24:16,359 Speaker 1: You're gonna be like, what on a second, you said 457 00:24:16,400 --> 00:24:20,439 Speaker 1: move through space? Right? That's fine, so you can't travel 458 00:24:20,440 --> 00:24:22,720 Speaker 1: through a light year of space in less than a year. 459 00:24:23,000 --> 00:24:25,440 Speaker 1: But what if you didn't want to move through space? Right? 460 00:24:25,600 --> 00:24:28,560 Speaker 1: What if you squeeze space itself? Right? Or if you 461 00:24:28,680 --> 00:24:31,480 Speaker 1: stretch space? And that's the basis of these warp drive 462 00:24:31,560 --> 00:24:34,400 Speaker 1: ideas is to get around it by saying I don't 463 00:24:34,400 --> 00:24:36,560 Speaker 1: want to go all the way to Alpha Centauri. I 464 00:24:36,600 --> 00:24:39,640 Speaker 1: want to squeeze the distance between here and Alpha Centauri. 465 00:24:40,400 --> 00:24:43,080 Speaker 1: Or I want to create this warp bubble which continuously 466 00:24:43,200 --> 00:24:45,679 Speaker 1: is like squeezing the space in front of me, so 467 00:24:45,720 --> 00:24:48,560 Speaker 1: I can move really really fall What what what would 468 00:24:48,560 --> 00:24:51,480 Speaker 1: have been otherwise really far in a short amount of time, 469 00:24:52,359 --> 00:24:55,120 Speaker 1: and and that way you can get somewhere which would 470 00:24:55,160 --> 00:24:57,040 Speaker 1: have taken light a long time to get there, but 471 00:24:57,080 --> 00:24:59,960 Speaker 1: it only takes you a few moments because you've effectively 472 00:25:00,080 --> 00:25:04,399 Speaker 1: shortened that distance. So I think that's totally plausible. Um, 473 00:25:04,440 --> 00:25:08,919 Speaker 1: I think it's far, far beyond our abilities. You know, 474 00:25:08,960 --> 00:25:11,800 Speaker 1: it's sort of like this moment when physicists pass things 475 00:25:11,800 --> 00:25:15,119 Speaker 1: off to engineers, you know, like we're interested in is 476 00:25:15,119 --> 00:25:18,600 Speaker 1: it totally possible or totally impossible. Once we decide it's 477 00:25:18,680 --> 00:25:21,920 Speaker 1: probably possible, then it's a practical question of like how 478 00:25:21,920 --> 00:25:25,040 Speaker 1: do you focus that much energy in order to accomplish that? 479 00:25:25,200 --> 00:25:28,199 Speaker 1: How do you actually build something which does this? And 480 00:25:28,240 --> 00:25:30,439 Speaker 1: that's a whole separate question. And you know, there are 481 00:25:30,440 --> 00:25:33,840 Speaker 1: even other crazier ideas for how to get far through 482 00:25:33,880 --> 00:25:37,240 Speaker 1: space which take advantage of this this new sort of 483 00:25:37,359 --> 00:25:40,479 Speaker 1: modern conception of space, and that's like, don't even go 484 00:25:40,560 --> 00:25:44,320 Speaker 1: through any space at all. General relativity tells us that 485 00:25:44,400 --> 00:25:48,800 Speaker 1: you can be creative about assigning the distances between bits 486 00:25:48,800 --> 00:25:50,800 Speaker 1: of space. Right, it doesn't have to be you lay 487 00:25:50,800 --> 00:25:53,000 Speaker 1: out a grid and everything that's next to each other 488 00:25:53,040 --> 00:25:56,359 Speaker 1: has equal distances. Right, mass can change the relationship of 489 00:25:56,440 --> 00:25:59,480 Speaker 1: points in space. And it's more than just like taking 490 00:25:59,520 --> 00:26:02,040 Speaker 1: a she and stretching it and squeezing it to make 491 00:26:02,119 --> 00:26:06,200 Speaker 1: gentle differences. You can have crazy rear arrangements. You can 492 00:26:06,280 --> 00:26:09,760 Speaker 1: connect bits of space which are not adjacent to each other. 493 00:26:10,400 --> 00:26:13,280 Speaker 1: And that's what we call a wormhole, is a connection 494 00:26:13,280 --> 00:26:15,959 Speaker 1: between bits of space which you know, have no reason 495 00:26:16,040 --> 00:26:18,080 Speaker 1: otherwise to be next to each other. But it's like, 496 00:26:18,480 --> 00:26:21,760 Speaker 1: I'm here in Orange County, you're in Atlanta. What if 497 00:26:21,800 --> 00:26:25,880 Speaker 1: we just somehow said Orange County is next to Atlanta, 498 00:26:26,359 --> 00:26:29,240 Speaker 1: and you know, we just rearrange the connections. That's what 499 00:26:29,280 --> 00:26:34,399 Speaker 1: a wormhole does. And shockingly, crazily, mind bogglingly that's not 500 00:26:34,480 --> 00:26:37,280 Speaker 1: against the rules. Yeah, this makes me think of the 501 00:26:37,359 --> 00:26:42,159 Speaker 1: examples we saw in the Hyperion novels where you had, uh, 502 00:26:42,200 --> 00:26:45,080 Speaker 1: you know, essentially warp gates that were allowing a river 503 00:26:45,160 --> 00:26:47,800 Speaker 1: in one world to flow into a river in the 504 00:26:47,840 --> 00:26:51,679 Speaker 1: other world, which, you know, if it feels completely fantastic, 505 00:26:51,760 --> 00:26:54,120 Speaker 1: but what what you're saying, if you lawyer up appropriately, 506 00:26:54,160 --> 00:26:57,840 Speaker 1: it's not completely out of the realm of possibility. Yeah, 507 00:26:57,880 --> 00:26:59,880 Speaker 1: it's not out of the realm of possibility at all. 508 00:27:00,440 --> 00:27:03,440 Speaker 1: And it's the kind of thing which might never be practical. 509 00:27:03,720 --> 00:27:06,560 Speaker 1: They might be that we're never able to build something 510 00:27:06,600 --> 00:27:08,920 Speaker 1: which allows you to have a house where your bathroom 511 00:27:08,960 --> 00:27:10,919 Speaker 1: is in one planet, in your living room is another. 512 00:27:11,160 --> 00:27:15,000 Speaker 1: I love that book, Um, But also might be totally possible, 513 00:27:15,000 --> 00:27:17,280 Speaker 1: and it might be seem impossible, and then somebody has 514 00:27:17,280 --> 00:27:19,160 Speaker 1: a breakthrough, like, oh, it turns out it's a lot 515 00:27:19,160 --> 00:27:22,000 Speaker 1: easier than we thought. And it used to cost um 516 00:27:22,119 --> 00:27:25,000 Speaker 1: the entire energy output of the human race for a 517 00:27:25,080 --> 00:27:28,360 Speaker 1: year just to transmit a particle through a wormhole. Now 518 00:27:28,400 --> 00:27:30,359 Speaker 1: we can do it for or five cents, you know, 519 00:27:30,480 --> 00:27:32,359 Speaker 1: and then the next year that's an app for it, right, 520 00:27:32,600 --> 00:27:36,359 Speaker 1: and sort of the progression of technology, And you know, 521 00:27:36,400 --> 00:27:40,400 Speaker 1: the way a wormhole would work is conceptually quite tricky. Still. 522 00:27:40,440 --> 00:27:42,520 Speaker 1: You need to create a black hole, you need to 523 00:27:42,560 --> 00:27:44,760 Speaker 1: open this wormhole up, you need to keep it open. 524 00:27:45,160 --> 00:27:48,120 Speaker 1: It might require the creation of exotic matter and all 525 00:27:48,160 --> 00:27:51,920 Speaker 1: sorts of stuff, but it's tactically not impossible. And that's 526 00:27:52,280 --> 00:27:55,399 Speaker 1: that's excite to me, um, mostly because I'd love to 527 00:27:55,480 --> 00:27:58,840 Speaker 1: visit these other star systems and walk on another planet, 528 00:27:58,920 --> 00:28:01,439 Speaker 1: or at least have humans walk on other planets and 529 00:28:01,440 --> 00:28:04,760 Speaker 1: tell us about it, you know, um, it feels frustrated 530 00:28:04,800 --> 00:28:07,920 Speaker 1: to be stuck in this tiny little island of our 531 00:28:08,040 --> 00:28:11,240 Speaker 1: universe and not able to explore the neighborhood. And so 532 00:28:11,680 --> 00:28:14,880 Speaker 1: if warp drives and wormholes could be built, then I'm 533 00:28:14,920 --> 00:28:16,879 Speaker 1: all for it. So yeah, I'd love to invest in 534 00:28:16,920 --> 00:28:22,120 Speaker 1: your company. So to come back to another question about 535 00:28:22,119 --> 00:28:25,879 Speaker 1: the properties of space, I was thinking about, um, So 536 00:28:25,920 --> 00:28:29,679 Speaker 1: we think of space as a kind of undifferentiated, uncountable 537 00:28:29,800 --> 00:28:33,320 Speaker 1: mass of potentially occupied territory, kind of the way you 538 00:28:33,400 --> 00:28:36,080 Speaker 1: use the analogy of water earlier, the way we think 539 00:28:36,080 --> 00:28:38,560 Speaker 1: about water. But of course in the modern world we 540 00:28:38,640 --> 00:28:42,239 Speaker 1: know that water is not actually continuous and uncountable. It's 541 00:28:42,240 --> 00:28:45,040 Speaker 1: a made up of h two molecules. In theory, you 542 00:28:45,040 --> 00:28:47,880 Speaker 1: could separate them out and count them. Is there any 543 00:28:48,000 --> 00:28:52,320 Speaker 1: evidence that space works like that? Are their smallest indivisible 544 00:28:52,440 --> 00:28:55,960 Speaker 1: units of space that could be counted? And does anybody 545 00:28:55,960 --> 00:28:58,880 Speaker 1: have any ideas for how to look into this question? Yeah, 546 00:28:58,920 --> 00:29:01,600 Speaker 1: that's a wonderful question. The short answer is that we 547 00:29:01,640 --> 00:29:04,760 Speaker 1: think space should be pixelated, and we think that there 548 00:29:04,760 --> 00:29:08,760 Speaker 1: should be a smallest meaningful unit of space. But the 549 00:29:08,880 --> 00:29:11,840 Speaker 1: arguments are kind of fuzzy, and it goes something like this, 550 00:29:11,960 --> 00:29:14,320 Speaker 1: you know, we look around in the universe and we 551 00:29:14,360 --> 00:29:18,280 Speaker 1: see that everything at the smallest scale is quantized. Like 552 00:29:18,400 --> 00:29:21,280 Speaker 1: you can have one electron, you can have two electrons. 553 00:29:21,440 --> 00:29:24,960 Speaker 1: You can't have one point six one electrons. Electrons in 554 00:29:25,040 --> 00:29:27,320 Speaker 1: bound states have energy levels. You can be an energy 555 00:29:27,400 --> 00:29:29,960 Speaker 1: level one or two. You can't be at one point 556 00:29:29,960 --> 00:29:33,920 Speaker 1: to one. Right, the universe seems to be quantized everything, 557 00:29:34,640 --> 00:29:38,520 Speaker 1: excitations of quantum fields. Everything comes down to numbers, integers, 558 00:29:38,560 --> 00:29:42,440 Speaker 1: not real numbers, but integers. And so we imagine that 559 00:29:42,480 --> 00:29:45,960 Speaker 1: as we zoom in on space smaller and smaller and smaller, 560 00:29:46,400 --> 00:29:50,360 Speaker 1: that we should similarly see the smallest bit of space. 561 00:29:51,440 --> 00:29:54,200 Speaker 1: It would sort of be counter a lot of what 562 00:29:54,240 --> 00:29:57,520 Speaker 1: we imagine to be foundational to quantum mechanics if it 563 00:29:57,640 --> 00:30:00,880 Speaker 1: wasn't right, if you could always zoom into a smaller space. 564 00:30:01,360 --> 00:30:04,000 Speaker 1: And so there's this idea that space could be made 565 00:30:04,040 --> 00:30:07,520 Speaker 1: out of these basic units, these pixels. And you can 566 00:30:07,520 --> 00:30:09,760 Speaker 1: think of it either it's like space being pixels or 567 00:30:09,800 --> 00:30:13,720 Speaker 1: space being sort of made out of this foam um. 568 00:30:13,920 --> 00:30:16,720 Speaker 1: And you know, that's not a very strong argument, but 569 00:30:17,000 --> 00:30:19,640 Speaker 1: it's it's consistent. You know, you find these general principles 570 00:30:19,640 --> 00:30:21,760 Speaker 1: who say, hey, the universe seems to work this way, 571 00:30:22,080 --> 00:30:24,800 Speaker 1: and so it should work this way in all categories. 572 00:30:24,840 --> 00:30:27,680 Speaker 1: It should every part of it should follow these rules. 573 00:30:27,720 --> 00:30:31,480 Speaker 1: Are there any ideas for types of experiments that could 574 00:30:31,480 --> 00:30:33,680 Speaker 1: test for this right now? Where is? That's just totally 575 00:30:33,720 --> 00:30:36,360 Speaker 1: beyond our even guests of how to how to look 576 00:30:36,360 --> 00:30:39,080 Speaker 1: for right now? Well, it's hard to know because we 577 00:30:39,120 --> 00:30:41,880 Speaker 1: don't know how big these pixels should be. Right we 578 00:30:42,120 --> 00:30:44,920 Speaker 1: let's think about scales for example, like we can look 579 00:30:44,960 --> 00:30:48,960 Speaker 1: at really small things using particle colliders. For example, with 580 00:30:49,000 --> 00:30:51,840 Speaker 1: a large hadron collider at certain we can zoom in 581 00:30:51,920 --> 00:30:54,120 Speaker 1: and see things that are about ten to the minus 582 00:30:54,200 --> 00:30:57,920 Speaker 1: twenty meters. That's pretty small, um. But if we had 583 00:30:57,920 --> 00:31:01,400 Speaker 1: to make a guess for how small these space pixels 584 00:31:01,400 --> 00:31:03,800 Speaker 1: would be, we don't really have a lot of good 585 00:31:03,800 --> 00:31:05,760 Speaker 1: reasons to guess. And what we do is we just 586 00:31:05,800 --> 00:31:08,040 Speaker 1: sort of take all the numbers we have and we 587 00:31:08,200 --> 00:31:11,280 Speaker 1: rearrange them until they give us something that have units 588 00:31:11,320 --> 00:31:13,800 Speaker 1: of a meter. We're like, okay, take the speed of light. 589 00:31:14,240 --> 00:31:18,400 Speaker 1: You know, that's meters per second multiplied by planks constant. Alright, 590 00:31:18,400 --> 00:31:22,840 Speaker 1: that has energy units. So keep throwing in fundamental constant 591 00:31:22,880 --> 00:31:24,840 Speaker 1: to the universe until you get something that has units 592 00:31:24,840 --> 00:31:26,800 Speaker 1: of meters, and you can do it, and you get 593 00:31:26,840 --> 00:31:29,560 Speaker 1: a number, and that number is about ten to the 594 00:31:29,600 --> 00:31:33,040 Speaker 1: minus thirty five meters, and it's called the plank length. 595 00:31:33,680 --> 00:31:36,120 Speaker 1: And it sounds like a really deep insight. I mean, 596 00:31:36,120 --> 00:31:39,280 Speaker 1: it's really nothing more clever than dimensional analysis. It's just saying, 597 00:31:39,600 --> 00:31:41,920 Speaker 1: how can I get a unit of meter? Doesn't mean 598 00:31:42,000 --> 00:31:44,720 Speaker 1: that that's the fundamental scale of the universe, doesn't mean 599 00:31:45,120 --> 00:31:48,160 Speaker 1: that space pixels are that size, but it's the only 600 00:31:48,200 --> 00:31:50,400 Speaker 1: thing we can do. And often in science we start 601 00:31:50,400 --> 00:31:53,040 Speaker 1: with like, let's start with the dumbest idea because that's 602 00:31:53,040 --> 00:31:55,040 Speaker 1: all we can do, and then let's get more sophisticated. 603 00:31:55,760 --> 00:31:59,520 Speaker 1: So if that's the case, and if space pixels are 604 00:31:59,720 --> 00:32:03,800 Speaker 1: ten to the minus thirty five meters, that's really far 605 00:32:03,920 --> 00:32:07,400 Speaker 1: from what we can see today, right, that's fifteen orders 606 00:32:07,440 --> 00:32:10,840 Speaker 1: of magnitude from what we can see. That's like, if 607 00:32:10,880 --> 00:32:14,960 Speaker 1: you can see whole solar systems, then one over one, 608 00:32:14,960 --> 00:32:16,840 Speaker 1: one over ten of the fifteen would be like seeing 609 00:32:16,840 --> 00:32:19,200 Speaker 1: a meter stick. So it's like saying I can barely 610 00:32:19,200 --> 00:32:22,320 Speaker 1: detect solar systems and other galaxies. Okay, well, can you 611 00:32:22,360 --> 00:32:24,520 Speaker 1: see a meter stick on the surface of a planet? 612 00:32:24,640 --> 00:32:27,640 Speaker 1: In another galaxy. No, I mean we're not even close. 613 00:32:28,520 --> 00:32:31,600 Speaker 1: So we're trillions of scale factors away from being able 614 00:32:31,640 --> 00:32:35,760 Speaker 1: to see these things in particle collisions. Um. But there's 615 00:32:35,760 --> 00:32:39,400 Speaker 1: a whole area of research that's built up the other directions. 616 00:32:39,600 --> 00:32:42,040 Speaker 1: Let's start from the bottom instead of starting from the 617 00:32:42,040 --> 00:32:44,880 Speaker 1: top and like breaking up protons and electrons into smaller 618 00:32:44,880 --> 00:32:46,680 Speaker 1: bits all the way down to the plank scale, Let's 619 00:32:46,680 --> 00:32:49,200 Speaker 1: start from the bottom. Imagine that it's true. Can we 620 00:32:49,240 --> 00:32:51,440 Speaker 1: sort of build up and come up with the theory 621 00:32:51,440 --> 00:32:54,600 Speaker 1: of physics and then make a prediction? Right? And that's 622 00:32:54,640 --> 00:32:58,280 Speaker 1: this this group of of theories called loop quantum gravity, 623 00:32:58,360 --> 00:33:01,240 Speaker 1: and it's really fascinating stuff, and it's you know, they've 624 00:33:01,960 --> 00:33:05,959 Speaker 1: instead of trying to bring general relativity together with quantum 625 00:33:06,000 --> 00:33:10,360 Speaker 1: field theory by saying, oh, let's turn gravity into a 626 00:33:10,400 --> 00:33:12,720 Speaker 1: quantum field theory, they go the other direction. They say, 627 00:33:12,800 --> 00:33:16,520 Speaker 1: let's take space and make it into quantized units. Let's 628 00:33:16,600 --> 00:33:18,840 Speaker 1: chop it up in the little bits and imagine that 629 00:33:18,880 --> 00:33:21,880 Speaker 1: the quantized. So then as space is expanding, you're like 630 00:33:22,080 --> 00:33:25,320 Speaker 1: popping off new little bits of space, which is sort 631 00:33:25,320 --> 00:33:28,200 Speaker 1: of conceptually hard to imagine. But your question really was like, 632 00:33:28,840 --> 00:33:31,360 Speaker 1: have we figured that out, could we possibly see it? 633 00:33:31,880 --> 00:33:34,440 Speaker 1: And so far that the whole field is sort of 634 00:33:34,520 --> 00:33:37,440 Speaker 1: in its infancy. You know, it's decades old. They only 635 00:33:37,480 --> 00:33:40,560 Speaker 1: realized if you know, fifty years ago, was even possible, 636 00:33:40,600 --> 00:33:43,440 Speaker 1: and how to do basic calculations and how to just 637 00:33:43,520 --> 00:33:46,840 Speaker 1: get simple stuff right. Um, But the short answer is, 638 00:33:46,960 --> 00:33:49,280 Speaker 1: and we could answer all these questions, we could resolve 639 00:33:49,280 --> 00:33:53,200 Speaker 1: all these mysteries if we could see inside a black hole. 640 00:33:54,320 --> 00:33:58,960 Speaker 1: You don't happen to have a black hole, dude, Uh, 641 00:33:59,000 --> 00:34:01,360 Speaker 1: that's sort of impossable, right, Like you're not you're not 642 00:34:01,400 --> 00:34:03,920 Speaker 1: getting information out of a black hole? Is that correct? 643 00:34:04,160 --> 00:34:06,400 Speaker 1: That's exactly right. And that's the frustrating thing is that 644 00:34:06,480 --> 00:34:09,560 Speaker 1: like gravity is very very weak, it's a very weak force. 645 00:34:09,600 --> 00:34:12,719 Speaker 1: It takes a lot for gravity to do anything very powerful. 646 00:34:13,239 --> 00:34:16,080 Speaker 1: But inside a black hole you have in tremendous gravity, 647 00:34:16,160 --> 00:34:19,040 Speaker 1: so much gravity that it could reveal things like you know, 648 00:34:19,239 --> 00:34:21,800 Speaker 1: the creation of new bits of space or the distortion 649 00:34:21,840 --> 00:34:25,560 Speaker 1: of space, or it could show us like what's, um, 650 00:34:25,600 --> 00:34:28,479 Speaker 1: what's the matter distribution like inside a black hole? Because 651 00:34:28,520 --> 00:34:32,120 Speaker 1: general relativity says that there's a singularity, that there's all 652 00:34:32,200 --> 00:34:36,440 Speaker 1: this mass concentrated in a single dot zero volume but 653 00:34:36,480 --> 00:34:39,680 Speaker 1: if space is pixelated, if loop quantum gravity is right, 654 00:34:39,960 --> 00:34:42,560 Speaker 1: then you can't have a tiny infinitesimal dot. You have 655 00:34:42,640 --> 00:34:45,399 Speaker 1: need to have a basic unit of space. So if 656 00:34:45,440 --> 00:34:47,399 Speaker 1: we could see what was going on inside a black hole, 657 00:34:47,440 --> 00:34:50,160 Speaker 1: we could see what happens when gravity tries to compress 658 00:34:50,239 --> 00:34:53,480 Speaker 1: things down to these tiny units of space. But you're right, 659 00:34:54,000 --> 00:34:56,680 Speaker 1: all the secret to the universe exists inside black holes, 660 00:34:56,880 --> 00:35:00,359 Speaker 1: but they are unobservable. Will never get that information and out, 661 00:35:00,680 --> 00:35:03,640 Speaker 1: which is so frustrating. It's like if you know, the 662 00:35:03,719 --> 00:35:05,640 Speaker 1: oracle says, here are all the answers, and I'm gonna 663 00:35:05,640 --> 00:35:06,960 Speaker 1: put them in a box, which if you try to 664 00:35:07,000 --> 00:35:09,800 Speaker 1: open it destroys all the answers. It's like some cruel 665 00:35:09,800 --> 00:35:12,440 Speaker 1: Greek fable or something. You know. Also a really safe 666 00:35:12,440 --> 00:35:15,560 Speaker 1: place to hide the secrets of the universe, right, that's right, 667 00:35:15,600 --> 00:35:17,640 Speaker 1: and all your passwords. I keep all my passwords in 668 00:35:17,680 --> 00:35:22,040 Speaker 1: a black hole. Just think. So the short answer is 669 00:35:22,040 --> 00:35:25,880 Speaker 1: we're not anywhere close to discovering the basic pixels of space. 670 00:35:26,400 --> 00:35:30,120 Speaker 1: But I think if you pulled physicists in them would 671 00:35:30,120 --> 00:35:33,480 Speaker 1: say that space is probably pixelated. So I'm sorry if 672 00:35:33,520 --> 00:35:35,920 Speaker 1: I if you already alluded to this and I missed it, 673 00:35:35,960 --> 00:35:40,080 Speaker 1: But um, so would you say looking for pixelated space 674 00:35:40,120 --> 00:35:43,839 Speaker 1: the smallest units of space is something that could potentially 675 00:35:43,880 --> 00:35:46,960 Speaker 1: be done by experimental methods available to us if we had, 676 00:35:47,000 --> 00:35:49,920 Speaker 1: you know, the ultimate particle collider or energy levels you 677 00:35:49,960 --> 00:35:52,880 Speaker 1: know you couldn't that are nowhere near what we have today? 678 00:35:53,000 --> 00:35:55,840 Speaker 1: Or is it just like not within reach of any 679 00:35:55,920 --> 00:36:01,640 Speaker 1: reasonable experimental paradigm that we know about. That's a great question, um. 680 00:36:01,680 --> 00:36:04,000 Speaker 1: And one of the amazing things about particle colliders is 681 00:36:04,040 --> 00:36:06,520 Speaker 1: that there really is no limit to what they can do. 682 00:36:06,680 --> 00:36:10,160 Speaker 1: It's really just a money question. Like the more money 683 00:36:10,200 --> 00:36:13,160 Speaker 1: you give us, the bigger the particle collider we can build, 684 00:36:13,200 --> 00:36:17,400 Speaker 1: the faster we can shoot those particles around. And speed 685 00:36:17,480 --> 00:36:20,239 Speaker 1: is sort of inverse two distance, right, The faster your 686 00:36:20,280 --> 00:36:23,680 Speaker 1: particles are going, the smaller the distance they can probe. 687 00:36:24,040 --> 00:36:26,719 Speaker 1: And so there's really no limit. If we built a 688 00:36:26,840 --> 00:36:30,560 Speaker 1: Milky Way size particle collider, then yes, we could answer 689 00:36:30,640 --> 00:36:34,080 Speaker 1: these questions, and uh, you know, we could find space 690 00:36:34,120 --> 00:36:37,680 Speaker 1: pixels and we could you know, see quantum effects at 691 00:36:37,719 --> 00:36:40,640 Speaker 1: this level. Um, but you know that would cost us. 692 00:36:40,680 --> 00:36:42,239 Speaker 1: I don't even know if there's a number for the 693 00:36:42,239 --> 00:36:45,080 Speaker 1: amount of money. If so, be bigger than this recent 694 00:36:45,120 --> 00:36:48,239 Speaker 1: stimulus by a lot. So you're saying it would not 695 00:36:48,320 --> 00:36:51,440 Speaker 1: be like, you know, something five to ten times bigger 696 00:36:51,440 --> 00:36:53,239 Speaker 1: than the large had round collider. It would need to 697 00:36:53,239 --> 00:36:55,480 Speaker 1: be like galaxy sized or something. Yeah, it have to 698 00:36:55,520 --> 00:36:59,160 Speaker 1: be like ten to the fifteen times larger than the 699 00:36:59,239 --> 00:37:01,839 Speaker 1: larger run colider. And that would be like I don't 700 00:37:01,880 --> 00:37:03,439 Speaker 1: even know what the acronym would be like, you can't 701 00:37:03,480 --> 00:37:05,120 Speaker 1: just call it a large hage junk collider. You need 702 00:37:05,160 --> 00:37:07,560 Speaker 1: like a very very very very very large hit junk 703 00:37:07,600 --> 00:37:12,560 Speaker 1: lider V to the fifteen LHC or something. Nobody's even 704 00:37:12,600 --> 00:37:15,000 Speaker 1: asking for that money. But yeah, there's no limit to 705 00:37:15,440 --> 00:37:18,319 Speaker 1: to sort of how small we can peer down if 706 00:37:18,400 --> 00:37:22,920 Speaker 1: we have really powerful colliders and we know the technology right, like, um, 707 00:37:23,120 --> 00:37:26,240 Speaker 1: we just add more little boosters to make the particles 708 00:37:26,239 --> 00:37:29,120 Speaker 1: go faster. Um. But you know, we also are working 709 00:37:29,160 --> 00:37:32,000 Speaker 1: on other kinds of technologies to make these colliders more 710 00:37:32,000 --> 00:37:36,360 Speaker 1: powerful without having to make them ridiculously big and expensive, 711 00:37:37,080 --> 00:37:39,560 Speaker 1: because currently we're limited by sort of how fast we 712 00:37:39,560 --> 00:37:42,520 Speaker 1: can make these particles move because it takes this these 713 00:37:42,560 --> 00:37:45,720 Speaker 1: little units to give them a kick and then magnets 714 00:37:45,800 --> 00:37:48,760 Speaker 1: to bend them. But if we can make those accelerators, 715 00:37:48,760 --> 00:37:51,759 Speaker 1: the little units of accelerators, better and faster and more 716 00:37:51,800 --> 00:37:55,120 Speaker 1: compact than we could build like tabletop accelerators. There are 717 00:37:55,120 --> 00:37:58,120 Speaker 1: people here you see Irvine, working on these plasma wakefield 718 00:37:58,200 --> 00:38:01,759 Speaker 1: devices to try to get particles accelerated to really high 719 00:38:01,880 --> 00:38:05,759 Speaker 1: energies and very short distances um and then it might 720 00:38:05,800 --> 00:38:08,680 Speaker 1: be possible to you know, peel back a layer of 721 00:38:08,719 --> 00:38:11,920 Speaker 1: reality and see what's going on underneath the without spending 722 00:38:12,000 --> 00:38:15,640 Speaker 1: ten of the fifteen trillion dollars. So we've been looking 723 00:38:15,680 --> 00:38:19,200 Speaker 1: a lot at the very smallest properties of space. I say, 724 00:38:19,200 --> 00:38:22,279 Speaker 1: we zoom out to the biggest possible, uh way of 725 00:38:22,320 --> 00:38:25,040 Speaker 1: looking at space and talk about the shape of the 726 00:38:25,120 --> 00:38:28,239 Speaker 1: universe we live in as a whole. Um. So, yeah, 727 00:38:28,560 --> 00:38:31,320 Speaker 1: so you've I was reading an article that you and 728 00:38:31,400 --> 00:38:33,759 Speaker 1: Jorge wrote about this. Uh could you talk a little 729 00:38:33,760 --> 00:38:36,239 Speaker 1: bit about the shape of the universe. Yeah, the shape 730 00:38:36,280 --> 00:38:38,879 Speaker 1: of the universe is a wonderful question. It's it's sort 731 00:38:38,880 --> 00:38:41,680 Speaker 1: of hard to imagine because I think people again think 732 00:38:41,719 --> 00:38:43,360 Speaker 1: about the shape of the universe, they think about like 733 00:38:43,400 --> 00:38:45,440 Speaker 1: a big blob, and then when like, what is the 734 00:38:45,520 --> 00:38:47,160 Speaker 1: shape of that blob? Is it, you know, look like 735 00:38:47,200 --> 00:38:49,000 Speaker 1: a pile of dog poop or like a bagel, or 736 00:38:49,000 --> 00:38:51,520 Speaker 1: like a doughnut or whatever. But when we talk about 737 00:38:51,560 --> 00:38:55,200 Speaker 1: the shape of the universe again, we're talking about something intrinsic, right, 738 00:38:55,239 --> 00:38:57,600 Speaker 1: We're talking about how do the pieces of the universe 739 00:38:57,640 --> 00:39:00,640 Speaker 1: relate to each other? Because we don't imagine that the 740 00:39:00,680 --> 00:39:04,480 Speaker 1: universe is like sitting in some larger space. We're not 741 00:39:04,560 --> 00:39:07,720 Speaker 1: asking like, if you were outside the universe and looking 742 00:39:07,760 --> 00:39:10,280 Speaker 1: at it, which shape would it have. We're really talking 743 00:39:10,320 --> 00:39:13,640 Speaker 1: about how does the universe curve? You know, like when 744 00:39:13,680 --> 00:39:17,480 Speaker 1: you put mass in a solar system, it bends space 745 00:39:17,800 --> 00:39:21,080 Speaker 1: so that planets move in according to these geodesics, which 746 00:39:21,080 --> 00:39:23,400 Speaker 1: happen to be orbits. So we're really talking about the 747 00:39:23,480 --> 00:39:28,120 Speaker 1: large scale like bending of the universe. And you know, 748 00:39:28,200 --> 00:39:32,200 Speaker 1: as you put stuff in the universe, planets, stars, whatever, 749 00:39:32,400 --> 00:39:34,960 Speaker 1: the universe bends in such a way so that it 750 00:39:35,080 --> 00:39:38,040 Speaker 1: would tend to collapse, right, tend things We tend to 751 00:39:38,040 --> 00:39:40,879 Speaker 1: sort of roll towards each other, moved towards each other, 752 00:39:41,160 --> 00:39:44,319 Speaker 1: so that gets space one curvature. But what we've done 753 00:39:44,400 --> 00:39:47,360 Speaker 1: is we've we've gone out, we've measured the curvature of space. 754 00:39:47,400 --> 00:39:50,800 Speaker 1: We've we've asked like how much stuff is there in space? 755 00:39:51,320 --> 00:39:54,040 Speaker 1: And how do these things balance each other? Because it 756 00:39:54,040 --> 00:39:57,280 Speaker 1: turns out there's a there's one way to bend the universe, 757 00:39:57,280 --> 00:39:59,359 Speaker 1: and that's by having mass, and there are other ways 758 00:39:59,400 --> 00:40:02,239 Speaker 1: to bend the universe the other direction. These things called 759 00:40:02,320 --> 00:40:04,880 Speaker 1: dark energy, which are contributing to the expansion of space, 760 00:40:05,040 --> 00:40:08,960 Speaker 1: actually has the opposite effect on this curvature. Some mass 761 00:40:09,000 --> 00:40:11,600 Speaker 1: bends it one way, dark energy bends it the other way, 762 00:40:11,760 --> 00:40:15,440 Speaker 1: and together the two things give you perfectly flat space. 763 00:40:15,840 --> 00:40:19,560 Speaker 1: So these two titanic forces which are balancing each other 764 00:40:19,760 --> 00:40:22,880 Speaker 1: and giving you space which is completely flat, meaning that 765 00:40:23,000 --> 00:40:26,120 Speaker 1: on average there is no curvature to the universe. That 766 00:40:26,560 --> 00:40:29,200 Speaker 1: that you know that things should move in straight lines. 767 00:40:29,640 --> 00:40:33,560 Speaker 1: So I've read the curvature of the universe described alternately 768 00:40:33,640 --> 00:40:37,120 Speaker 1: as flat and as almost flat. Could you help me 769 00:40:37,160 --> 00:40:39,279 Speaker 1: sort sort out the difference? There is one of those 770 00:40:39,320 --> 00:40:43,200 Speaker 1: just wrong or or what's going on? Well, it's a measurement, right, 771 00:40:43,560 --> 00:40:46,160 Speaker 1: and we're measuring the curvature of the universe. And roughly 772 00:40:46,200 --> 00:40:48,080 Speaker 1: how we do is we add up all these pieces 773 00:40:48,480 --> 00:40:50,360 Speaker 1: and we ask, you know, what do they come out to? 774 00:40:50,520 --> 00:40:53,000 Speaker 1: But they all have uncertainties, you know, we don't know 775 00:40:53,120 --> 00:40:55,920 Speaker 1: precisely how much stuff there is in the universe. We 776 00:40:55,960 --> 00:41:00,200 Speaker 1: don't know exactly how strong dark energy is. And we 777 00:41:00,280 --> 00:41:03,640 Speaker 1: get better and better measurements every year, and those measurements 778 00:41:03,640 --> 00:41:07,040 Speaker 1: are consistent with totally flat, right with adding up to 779 00:41:07,120 --> 00:41:10,560 Speaker 1: being exactly flat. But there's uncertainty there, and some measurements 780 00:41:10,600 --> 00:41:14,120 Speaker 1: suggest a tiny deviation from flat, and some measurements are 781 00:41:14,120 --> 00:41:17,040 Speaker 1: consistent with flat and other things, and so there's some 782 00:41:17,080 --> 00:41:19,719 Speaker 1: wiggle room there. And and we're trying to measure in 783 00:41:19,760 --> 00:41:22,359 Speaker 1: lots of different ways because we don't just trust one 784 00:41:22,360 --> 00:41:25,239 Speaker 1: experiment or one experiment or and so we try to 785 00:41:25,440 --> 00:41:29,160 Speaker 1: probe these things from different directions and sometimes they slightly disagree, 786 00:41:29,440 --> 00:41:32,359 Speaker 1: so there can be some sort of momentary controversy there. 787 00:41:32,840 --> 00:41:35,560 Speaker 1: But you know, I think the larger question is like, 788 00:41:35,640 --> 00:41:37,800 Speaker 1: why are we flat at all? You know, it seems 789 00:41:37,840 --> 00:41:41,240 Speaker 1: sort of weird once you discover the space can be curved, 790 00:41:41,320 --> 00:41:43,759 Speaker 1: to discover that our universe just sort of happens to 791 00:41:43,840 --> 00:41:46,719 Speaker 1: be flat. So you say just sort of happens to 792 00:41:46,760 --> 00:41:50,480 Speaker 1: be flat. That indicate that you think the flatness of 793 00:41:50,520 --> 00:41:54,320 Speaker 1: the universe, in your expert opinion, is basically a coincidence, 794 00:41:54,800 --> 00:41:57,600 Speaker 1: or do you think that that it's not a coincidence 795 00:41:57,640 --> 00:42:00,640 Speaker 1: that it's a downstream effect of some thing we don't 796 00:42:00,719 --> 00:42:05,200 Speaker 1: understand or some other variable. It depends right like um, 797 00:42:05,239 --> 00:42:07,720 Speaker 1: before we had this theory for how the universe began, 798 00:42:08,200 --> 00:42:10,960 Speaker 1: it seemed really weird to have a flat universe. Seemed 799 00:42:11,000 --> 00:42:13,560 Speaker 1: really strange for space to be so smooth and to 800 00:42:13,640 --> 00:42:17,720 Speaker 1: not have curvature, because as you put stuff in the universe, 801 00:42:17,840 --> 00:42:21,040 Speaker 1: it should sort of gather together, right, that's gravity, and 802 00:42:21,040 --> 00:42:23,279 Speaker 1: it should make it more and more curt and so 803 00:42:23,360 --> 00:42:26,160 Speaker 1: it's it's weird to start with the universe that's pretty 804 00:42:26,160 --> 00:42:28,400 Speaker 1: flat and then end up with the universe it's pretty flat, 805 00:42:28,440 --> 00:42:31,120 Speaker 1: Like it doesn't seem stable. It seems like if you 806 00:42:31,120 --> 00:42:34,560 Speaker 1: have any deviation from flatness, that deviation would build on 807 00:42:34,560 --> 00:42:36,799 Speaker 1: itself and build on itself and build on itself, and 808 00:42:36,840 --> 00:42:39,839 Speaker 1: eventually you'd be pretty far from flat. So then our 809 00:42:39,920 --> 00:42:43,120 Speaker 1: universe is pretty old. It's fourteen billion years old. This 810 00:42:43,160 --> 00:42:45,719 Speaker 1: has been going on for a long time. Why are 811 00:42:45,760 --> 00:42:48,319 Speaker 1: we still flat? And so for a long time that 812 00:42:48,440 --> 00:42:51,680 Speaker 1: was that seemed like a coincidence, like either we were 813 00:42:51,800 --> 00:42:55,120 Speaker 1: so closed to flat in the first few seconds that 814 00:42:55,200 --> 00:42:58,120 Speaker 1: we've hardly deviated it all, Like we're like balanced on 815 00:42:58,160 --> 00:43:01,640 Speaker 1: the knife's edge and we're still balanced fourteen billion years later, 816 00:43:01,840 --> 00:43:05,520 Speaker 1: which seems unlikely, or there's some reason for it. And 817 00:43:05,600 --> 00:43:08,359 Speaker 1: the explanation that we've come up with recently is this 818 00:43:08,440 --> 00:43:13,760 Speaker 1: idea of inflation, that the universe was stretched super quickly 819 00:43:14,040 --> 00:43:16,799 Speaker 1: in the first few moments of the universe that made 820 00:43:16,800 --> 00:43:20,320 Speaker 1: it essentially hyper hyper flat. It's like if you're standing 821 00:43:20,400 --> 00:43:22,759 Speaker 1: on a tennis ball. You look around, and you can 822 00:43:22,760 --> 00:43:24,759 Speaker 1: tell that the universe is a little bit curve, right, 823 00:43:24,760 --> 00:43:27,080 Speaker 1: because the tennis ball is a lot of curvature to it. 824 00:43:27,520 --> 00:43:29,840 Speaker 1: But if the tennis ball suddenly gets inflated to the 825 00:43:29,840 --> 00:43:31,959 Speaker 1: size of a planet where you look around, you can't 826 00:43:31,960 --> 00:43:34,560 Speaker 1: tell that the Earth is not flat, right, it seems 827 00:43:34,600 --> 00:43:37,680 Speaker 1: to be flat. And so that's what happened, we think 828 00:43:37,719 --> 00:43:40,040 Speaker 1: in the first few moments of the universe. That explains 829 00:43:40,080 --> 00:43:43,480 Speaker 1: how the universe got so flat in the beginning. So 830 00:43:43,600 --> 00:43:46,600 Speaker 1: if if this is what it is like in a 831 00:43:46,680 --> 00:43:49,680 Speaker 1: flat universe, I mean, is there any way to to 832 00:43:49,800 --> 00:43:52,520 Speaker 1: even discuss like what it would be like within a 833 00:43:52,680 --> 00:43:56,040 Speaker 1: round universe or a square universe or anything other than 834 00:43:56,080 --> 00:43:59,000 Speaker 1: a flat or almost flat universe. Yeah, Well, it has 835 00:43:59,160 --> 00:44:03,880 Speaker 1: really fascinating applications for like the possible sizes of the universe. Right, 836 00:44:03,920 --> 00:44:07,680 Speaker 1: if the universe is flat, then it can go on forever. Right, 837 00:44:07,719 --> 00:44:10,120 Speaker 1: you can just keep going forever because it can be 838 00:44:10,160 --> 00:44:12,960 Speaker 1: flat like an infinite sheet. Right, But in three dimensions, 839 00:44:13,520 --> 00:44:16,000 Speaker 1: if the universe is curved, like if the universe is 840 00:44:16,040 --> 00:44:19,280 Speaker 1: the surface of a sphere right in some higher dimensional space, 841 00:44:19,800 --> 00:44:23,359 Speaker 1: then it it might not be infinite. Right. It might 842 00:44:23,400 --> 00:44:26,120 Speaker 1: be that you move and you keep curving and eventually 843 00:44:26,120 --> 00:44:28,239 Speaker 1: you come back to where you were, and so it 844 00:44:28,239 --> 00:44:30,719 Speaker 1: could be infinite, but not necessarily have any edges, right 845 00:44:31,120 --> 00:44:32,880 Speaker 1: because like on the surface of the sphere or on 846 00:44:32,920 --> 00:44:35,600 Speaker 1: the surface of the Earth, you walk for long enough, 847 00:44:35,680 --> 00:44:37,200 Speaker 1: you come back to where you started. You don't like 848 00:44:37,440 --> 00:44:40,920 Speaker 1: run into the edge of the Earth. So the shape, 849 00:44:40,920 --> 00:44:43,520 Speaker 1: this curvature of the universe has a lot of consequences 850 00:44:43,560 --> 00:44:47,160 Speaker 1: for the potential size of the universe, And so if 851 00:44:47,200 --> 00:44:50,560 Speaker 1: it was curved, it wouldn't necessarily be infinite. Um, if 852 00:44:50,600 --> 00:44:53,759 Speaker 1: it's flat, that suggests it could be infinite, but it 853 00:44:53,840 --> 00:44:58,280 Speaker 1: also might not be. Right, there's ways to connect the universe. 854 00:44:58,440 --> 00:45:01,000 Speaker 1: It can be flat but also still be like weirdly 855 00:45:01,080 --> 00:45:04,600 Speaker 1: connected like an asteroids game, so that you come off 856 00:45:04,640 --> 00:45:06,480 Speaker 1: one side and you end up on the other side. 857 00:45:06,760 --> 00:45:10,240 Speaker 1: Because remember space can have these complicated, non trivial connections 858 00:45:10,280 --> 00:45:12,400 Speaker 1: between parts of it. The whole edge of the universe 859 00:45:12,440 --> 00:45:14,840 Speaker 1: could be basically a set of wormholes that bring you 860 00:45:14,880 --> 00:45:17,359 Speaker 1: back to the other side. All Right, we're gonna take 861 00:45:17,400 --> 00:45:22,799 Speaker 1: one more break, but we'll be right back. All right, 862 00:45:22,840 --> 00:45:25,839 Speaker 1: we're back. So I've got a question about the Big Bang. Then, 863 00:45:25,920 --> 00:45:28,680 Speaker 1: with respect to the the expansion of the universe, we 864 00:45:28,760 --> 00:45:30,920 Speaker 1: often hear, of course, the Big Bang was that the 865 00:45:31,000 --> 00:45:33,759 Speaker 1: universe was once in this hot, dense state, and then 866 00:45:33,800 --> 00:45:36,399 Speaker 1: there's this expansion. You you think, when you go through 867 00:45:36,400 --> 00:45:38,799 Speaker 1: this period of inflation, that seems to be the consensus 868 00:45:38,840 --> 00:45:42,279 Speaker 1: now and then we we keep expanding and cooling. But 869 00:45:42,960 --> 00:45:46,200 Speaker 1: what form does that expansion take with respect to space? 870 00:45:46,360 --> 00:45:49,480 Speaker 1: Does that mean that the universe or the contents of 871 00:45:49,480 --> 00:45:54,520 Speaker 1: the universe expanded into pre existing space, or that space 872 00:45:54,640 --> 00:45:58,799 Speaker 1: itself expanded, space itself expanded. The way I think about 873 00:45:58,800 --> 00:46:01,359 Speaker 1: it's not like a small blob of stuff that then 874 00:46:01,360 --> 00:46:05,520 Speaker 1: blew up and moved through space, but instead an infinite 875 00:46:05,560 --> 00:46:09,279 Speaker 1: universe created with infinite stuff in it. And then the 876 00:46:09,320 --> 00:46:14,040 Speaker 1: Big Bang happened simultaneously everywhere, all at once, meaning that 877 00:46:14,239 --> 00:46:17,360 Speaker 1: all that stuff just got diluted, like new space was 878 00:46:17,440 --> 00:46:21,279 Speaker 1: being created everywhere. Space was expanding, and it's not like 879 00:46:21,320 --> 00:46:24,960 Speaker 1: it was stretching stuff into what was previously empty space. 880 00:46:25,000 --> 00:46:28,320 Speaker 1: It was just creating new space everywhere between all the bits. 881 00:46:28,760 --> 00:46:31,960 Speaker 1: So what used to be hot and dense and intense 882 00:46:32,280 --> 00:46:35,160 Speaker 1: is now more dilute. And so I think one of 883 00:46:35,160 --> 00:46:38,160 Speaker 1: the biggest misconceptions that the Big Bang started off like 884 00:46:38,200 --> 00:46:40,520 Speaker 1: the whole universe the size of an atom, and then 885 00:46:40,520 --> 00:46:43,680 Speaker 1: it's just a big explosion where stuff moves through space. 886 00:46:44,239 --> 00:46:46,279 Speaker 1: But instead, I think it's much more natural to think 887 00:46:46,280 --> 00:46:50,720 Speaker 1: about the universe be created um infinite amount of stuff 888 00:46:50,719 --> 00:46:53,719 Speaker 1: created all at once, and then diluted and then expanded. 889 00:46:54,000 --> 00:46:56,880 Speaker 1: So that's like requires you to imagine an infinite creation 890 00:46:56,920 --> 00:46:59,680 Speaker 1: of stuff and then an infinite big bang on top 891 00:46:59,760 --> 00:47:02,400 Speaker 1: of it, which is sort of mind blowing and also 892 00:47:02,640 --> 00:47:06,439 Speaker 1: sort of more natural. I really like that explanation because 893 00:47:06,480 --> 00:47:10,239 Speaker 1: I feel like it places uh sit places that the 894 00:47:10,239 --> 00:47:13,959 Speaker 1: the individual thinker within the model, instead of placing us 895 00:47:14,000 --> 00:47:17,240 Speaker 1: trying to place us with outside of the model, which 896 00:47:17,520 --> 00:47:21,120 Speaker 1: which excuse this UH, this attempt to understand like what 897 00:47:21,520 --> 00:47:24,360 Speaker 1: space is, you know, and then you don't have to 898 00:47:24,400 --> 00:47:26,640 Speaker 1: ask questions like, well, where was the Big Bang? Was 899 00:47:26,680 --> 00:47:28,320 Speaker 1: it over there and over there? And we're close to 900 00:47:28,360 --> 00:47:30,879 Speaker 1: the center, and when we look around us, we see 901 00:47:31,040 --> 00:47:34,319 Speaker 1: everything is moving away from us, and there's no directionality 902 00:47:34,360 --> 00:47:36,239 Speaker 1: to it, like things over here moving away from us, 903 00:47:36,239 --> 00:47:38,600 Speaker 1: things over there moving away from us. And that's true 904 00:47:38,680 --> 00:47:42,080 Speaker 1: everywhere in the universe, which means that there is no center. 905 00:47:42,320 --> 00:47:45,840 Speaker 1: There's no place from which this explosion happened. It happened 906 00:47:45,880 --> 00:47:49,399 Speaker 1: everywhere all at once, and that's what differentiates sort of 907 00:47:49,640 --> 00:47:52,720 Speaker 1: things moving through space from the expansion of space itself. 908 00:47:53,800 --> 00:47:56,120 Speaker 1: This makes me wonder if, kind of like the idea 909 00:47:56,120 --> 00:47:59,319 Speaker 1: of bending in general relativity, if we're suffering from the 910 00:47:59,360 --> 00:48:02,120 Speaker 1: connotation ends of the word we happen to use. The 911 00:48:02,160 --> 00:48:07,240 Speaker 1: idea of expanding usually indicates like the pushing of boundaries 912 00:48:07,280 --> 00:48:10,920 Speaker 1: into areas that were previously out of bounds, Like if 913 00:48:10,920 --> 00:48:13,840 Speaker 1: you expand a map, you know you're pushing the edges out, 914 00:48:14,160 --> 00:48:16,080 Speaker 1: But that doesn't really make sense in this case. We're 915 00:48:16,080 --> 00:48:18,120 Speaker 1: talking about the expansion of space, So it would almost 916 00:48:18,160 --> 00:48:20,200 Speaker 1: make more sense to think about the Big Bang maybe 917 00:48:20,239 --> 00:48:24,799 Speaker 1: as a um a population of or I don't know, 918 00:48:24,880 --> 00:48:29,200 Speaker 1: a population of space expanding and infilling of space. Yeah. 919 00:48:29,239 --> 00:48:31,400 Speaker 1: I think of it like a take an infinite ruler, 920 00:48:31,960 --> 00:48:35,719 Speaker 1: right and mark off two dots, and then somebody stretches it. Right. Well, 921 00:48:35,719 --> 00:48:39,319 Speaker 1: it was infinite before, it's infinite now. But there's more 922 00:48:39,360 --> 00:48:42,920 Speaker 1: of it, right, And so space is really this like 923 00:48:43,200 --> 00:48:46,279 Speaker 1: it's it's it's more of a stretching, you know, than 924 00:48:46,320 --> 00:48:48,920 Speaker 1: an expansion. It's not an explosion. It's more of like 925 00:48:48,960 --> 00:48:51,759 Speaker 1: a Yeah, it's like a stretching. There has to be 926 00:48:51,800 --> 00:48:54,439 Speaker 1: a social distancing metaphor, and all of us I keep, 927 00:48:54,680 --> 00:48:59,000 Speaker 1: I keep kind of grasping for it. Well, I'm certainly 928 00:48:59,040 --> 00:49:01,839 Speaker 1: expanding inside my pants on a notice that they're all there. 929 00:49:02,120 --> 00:49:05,880 Speaker 1: They're all denser these days, and then before this quarantine. 930 00:49:06,280 --> 00:49:08,359 Speaker 1: But I think that's something that's hard to grapple with, 931 00:49:08,480 --> 00:49:12,800 Speaker 1: is this creation of an infinite universe or an infinite 932 00:49:12,800 --> 00:49:15,960 Speaker 1: amount of space. And people write us questions in our 933 00:49:16,000 --> 00:49:17,640 Speaker 1: podcast all the time, and one of the most common 934 00:49:17,719 --> 00:49:21,640 Speaker 1: questions is what is the universe expanding into? Right? And 935 00:49:21,680 --> 00:49:24,160 Speaker 1: I think that comes from this conception of the Big 936 00:49:24,200 --> 00:49:28,200 Speaker 1: Bang as a small dot which is then exploding, right, 937 00:49:28,800 --> 00:49:31,400 Speaker 1: or even if you imagine space as a chunk of 938 00:49:31,440 --> 00:49:35,080 Speaker 1: stuff and you understand the space itself is expanding, you 939 00:49:35,120 --> 00:49:38,160 Speaker 1: wonder what is it expanding into? And I think that's 940 00:49:38,200 --> 00:49:41,840 Speaker 1: this desperation to sort of place the universe in a 941 00:49:41,920 --> 00:49:45,840 Speaker 1: context is to say, alright, we started off by drawing 942 00:49:45,920 --> 00:49:48,600 Speaker 1: access lines and describing all the stuff happening in universe 943 00:49:48,840 --> 00:49:51,799 Speaker 1: in this sort of construct we imagine called space, which 944 00:49:51,880 --> 00:49:54,440 Speaker 1: was maybe philosophical or just a thought idea, and then 945 00:49:54,440 --> 00:49:56,760 Speaker 1: it turns out it's real. Well, we'd like to place 946 00:49:56,800 --> 00:49:59,960 Speaker 1: then that space in some sort of super space or 947 00:50:00,280 --> 00:50:03,719 Speaker 1: meta space. So sort of grapple with it. It's difficult 948 00:50:03,760 --> 00:50:05,920 Speaker 1: even for me or for cosmologists, I think, to still, 949 00:50:06,560 --> 00:50:09,000 Speaker 1: you know, grapple with this concept of space not being 950 00:50:09,120 --> 00:50:13,000 Speaker 1: in anything else, not necessarily sitting in a superspace or 951 00:50:13,040 --> 00:50:15,800 Speaker 1: a meta space on which you can define these axes. 952 00:50:15,840 --> 00:50:18,879 Speaker 1: It just sort of is inherent. So I'm sure you've 953 00:50:18,880 --> 00:50:21,240 Speaker 1: gotten this question before, but I think it always helps 954 00:50:21,280 --> 00:50:23,480 Speaker 1: to to try as best we can to imagine it 955 00:50:23,800 --> 00:50:27,000 Speaker 1: on our own level. So imagine you have a space ship, 956 00:50:27,080 --> 00:50:29,200 Speaker 1: you know, that can go faster than the light, as 957 00:50:29,200 --> 00:50:31,360 Speaker 1: fast as you possibly wanted to go, there's no limit 958 00:50:31,400 --> 00:50:34,080 Speaker 1: to it, and you just travel in the same direction 959 00:50:34,160 --> 00:50:38,120 Speaker 1: forever but what do you imagine happens then, Well, I 960 00:50:38,160 --> 00:50:40,680 Speaker 1: think you would really never get anywhere. I mean, you 961 00:50:40,800 --> 00:50:43,880 Speaker 1: leave the galaxy, and then you leave the local group 962 00:50:43,880 --> 00:50:47,040 Speaker 1: of galaxies, and then you're flying off towards another group 963 00:50:47,040 --> 00:50:50,040 Speaker 1: of galaxies. But that group of galaxies is moving away 964 00:50:50,080 --> 00:50:53,160 Speaker 1: from us faster than the speed of light. Right now. 965 00:50:53,200 --> 00:50:56,320 Speaker 1: It's not again physics lawyer talk, it's not moving through 966 00:50:56,360 --> 00:50:59,480 Speaker 1: space fasten the speed of light. New space is being 967 00:50:59,520 --> 00:51:03,000 Speaker 1: created between us and those galaxies faster than we could 968 00:51:03,080 --> 00:51:05,480 Speaker 1: move to it, faster than even a photon could fly 969 00:51:05,640 --> 00:51:08,160 Speaker 1: through it. So those galaxies, if you just sat here 970 00:51:08,160 --> 00:51:12,640 Speaker 1: on Earth, those galaxies are disappearing from our view. Eventually, 971 00:51:12,800 --> 00:51:15,919 Speaker 1: the photons being created by them will no longer get 972 00:51:15,960 --> 00:51:19,239 Speaker 1: to us. It's like if Lussin Bolt was running at you, 973 00:51:19,520 --> 00:51:21,920 Speaker 1: but somebody was laying track in front of him faster 974 00:51:22,000 --> 00:51:24,040 Speaker 1: than he was running. It doesn't matter how fast he is, 975 00:51:24,120 --> 00:51:26,520 Speaker 1: right if they're laying track faster, he's never going to 976 00:51:26,640 --> 00:51:29,520 Speaker 1: beat them. So, in that same way, those photons will 977 00:51:29,560 --> 00:51:31,600 Speaker 1: never get to us, and we will never get to 978 00:51:31,640 --> 00:51:36,000 Speaker 1: those galaxies, which means that the night sky is getting 979 00:51:36,080 --> 00:51:39,279 Speaker 1: darker and darker. Right things are literally falling off the 980 00:51:39,400 --> 00:51:44,040 Speaker 1: edge of the observable universe, and things are disappearing from 981 00:51:44,040 --> 00:51:47,640 Speaker 1: our view. You know, in fifty billion years or a 982 00:51:47,680 --> 00:51:50,000 Speaker 1: hundred billion years, it may be that there are no 983 00:51:50,200 --> 00:51:56,319 Speaker 1: galaxies visible in the sky. Imagine human civilization survives that long, 984 00:51:56,480 --> 00:51:58,880 Speaker 1: or maybe we have some apocalypse when we rebuild and 985 00:51:58,920 --> 00:52:01,759 Speaker 1: we start building human edge again, then there is no 986 00:52:02,040 --> 00:52:04,399 Speaker 1: Edwin Hubble moment when you look out in the sky 987 00:52:04,440 --> 00:52:07,480 Speaker 1: and discover distant galaxies and realize, oh, we're not alone 988 00:52:07,520 --> 00:52:10,080 Speaker 1: in the universe is expanding. They would never know that. 989 00:52:10,320 --> 00:52:12,200 Speaker 1: There would be no way for them to learn that, 990 00:52:12,719 --> 00:52:15,920 Speaker 1: and that to me is so tantalizing and frustrating to 991 00:52:16,080 --> 00:52:18,800 Speaker 1: know that that knowledge could be hidden, because I project 992 00:52:18,880 --> 00:52:20,760 Speaker 1: the other way. I'm like, all right, well, we're fourteen 993 00:52:20,760 --> 00:52:24,640 Speaker 1: billion years into the universe. What has already disappeared from 994 00:52:24,680 --> 00:52:28,320 Speaker 1: the night sky which we will never recover? What clues, 995 00:52:28,400 --> 00:52:32,600 Speaker 1: what incredible context are we missing about the night sky 996 00:52:32,640 --> 00:52:35,879 Speaker 1: that you know, astronomers thirteen billion years ago would laugh 997 00:52:35,920 --> 00:52:38,400 Speaker 1: at us for not understanding. We don't know, and we 998 00:52:38,520 --> 00:52:42,960 Speaker 1: probably never will, and that drives me crazy. So this 999 00:52:43,000 --> 00:52:45,000 Speaker 1: is our shot. We don't have time to re evolve 1000 00:52:45,040 --> 00:52:48,160 Speaker 1: from bacteria and do it again. That's right, that's right. 1001 00:52:48,200 --> 00:52:50,600 Speaker 1: If we haven't missed our shot already, we should scrape 1002 00:52:50,640 --> 00:52:52,920 Speaker 1: the bottom of the barrel and understand what's going on 1003 00:52:53,080 --> 00:52:55,719 Speaker 1: out there in the universe. You know, we wrote a 1004 00:52:55,719 --> 00:52:57,879 Speaker 1: whole book about it's called We Have No Idea, And 1005 00:52:58,280 --> 00:53:00,399 Speaker 1: the point of that book is that we don't even 1006 00:53:00,440 --> 00:53:03,480 Speaker 1: really know what the denominator is on our ignorance, Like 1007 00:53:03,600 --> 00:53:06,719 Speaker 1: what fraction of the universe do we have understood? You know, 1008 00:53:06,800 --> 00:53:09,200 Speaker 1: given the fact that we only in the last thirty 1009 00:53:09,280 --> 00:53:12,120 Speaker 1: years figured out that space is a thing and it's 1010 00:53:12,160 --> 00:53:15,279 Speaker 1: expanding and could do all these weird stuff, and the 1011 00:53:15,400 --> 00:53:18,000 Speaker 1: universe is growing and growing, that so many of our 1012 00:53:18,040 --> 00:53:21,160 Speaker 1: basic questions about the universe have different answers than we imagined, 1013 00:53:21,280 --> 00:53:24,440 Speaker 1: And we're discovering new basic questions like what is space? 1014 00:53:24,480 --> 00:53:26,840 Speaker 1: What is time? How many dimensions are there to space, 1015 00:53:26,840 --> 00:53:29,360 Speaker 1: which we didn't even get into. Um. It tells me 1016 00:53:29,400 --> 00:53:31,000 Speaker 1: that there's a lot of stuff that we don't even 1017 00:53:31,000 --> 00:53:33,120 Speaker 1: know to ask yet. And I would just hope we 1018 00:53:33,160 --> 00:53:35,239 Speaker 1: figure out where the questions are before we run out 1019 00:53:35,239 --> 00:53:37,600 Speaker 1: of time to answer them. So I've got a question 1020 00:53:37,680 --> 00:53:39,959 Speaker 1: going in another direction. This might not make any sense, 1021 00:53:40,040 --> 00:53:42,520 Speaker 1: Feel free to decline it if it doesn't. But I 1022 00:53:42,560 --> 00:53:45,719 Speaker 1: was wondering, does it make sense to think that the 1023 00:53:45,760 --> 00:53:51,279 Speaker 1: fundamental properties of physics are actually properties of space, you know, 1024 00:53:51,719 --> 00:53:54,359 Speaker 1: or of local space as we know it. I'm thinking about, 1025 00:53:54,360 --> 00:53:56,480 Speaker 1: for example, you know, I don't know relative strength of 1026 00:53:56,520 --> 00:53:59,320 Speaker 1: fundamental forces or the mass of the proton or something. 1027 00:53:59,800 --> 00:54:02,480 Speaker 1: Does the nature of space have anything to do with 1028 00:54:02,560 --> 00:54:05,719 Speaker 1: these constants or the laws of physics? And are they 1029 00:54:05,719 --> 00:54:08,759 Speaker 1: in some way contingent upon what kind of space we 1030 00:54:08,800 --> 00:54:11,840 Speaker 1: live in? Oh? My god. Absolutely, that's not a crazy idea. 1031 00:54:11,920 --> 00:54:14,160 Speaker 1: I mean, it is a crazy idea, but it's also real, 1032 00:54:14,760 --> 00:54:18,200 Speaker 1: Like the universe is a crazy idea. So um, A 1033 00:54:18,239 --> 00:54:20,400 Speaker 1: lot of the things that we consider to be fundamental 1034 00:54:20,440 --> 00:54:24,480 Speaker 1: about the universe are actually just properties of space and 1035 00:54:24,560 --> 00:54:27,960 Speaker 1: the way that space around here at least seems to behave. 1036 00:54:28,120 --> 00:54:32,520 Speaker 1: For example, we know that particles. The reason particles have mass, 1037 00:54:32,719 --> 00:54:36,160 Speaker 1: tiny little particles like electrons have mass, it's not because 1038 00:54:36,160 --> 00:54:38,319 Speaker 1: they have a little stuff to them. It's because they 1039 00:54:38,360 --> 00:54:41,040 Speaker 1: interact with this new field we discovered, the Higgs field, 1040 00:54:41,360 --> 00:54:44,040 Speaker 1: and it's in interacting with those fields that they get inertia. 1041 00:54:44,239 --> 00:54:47,080 Speaker 1: The reason a little electron when you push it it 1042 00:54:47,280 --> 00:54:49,840 Speaker 1: um takes some force to get it to move, is 1043 00:54:49,840 --> 00:54:51,800 Speaker 1: because it has some inertition. The inertia comes from the 1044 00:54:51,880 --> 00:54:56,160 Speaker 1: Higgs field. But where does the Higgs field come from? Well, 1045 00:54:56,160 --> 00:54:58,080 Speaker 1: the Higgs fields we talked about before is one of 1046 00:54:58,120 --> 00:55:01,120 Speaker 1: these quantum fields. It's part of space, and it's got 1047 00:55:01,160 --> 00:55:04,440 Speaker 1: some tension built into it. Like when the universe cooled 1048 00:55:04,480 --> 00:55:06,680 Speaker 1: in the very first few moments, there's a lot of 1049 00:55:06,800 --> 00:55:09,399 Speaker 1: energy in the universe sort of cooled down, cooled down, 1050 00:55:09,520 --> 00:55:11,719 Speaker 1: But the Higgs field got stuck. It didn't go all 1051 00:55:11,760 --> 00:55:13,480 Speaker 1: the way down to zero, got like stuck on a 1052 00:55:13,480 --> 00:55:17,279 Speaker 1: little shelf, and it's very happy there for now. But 1053 00:55:17,480 --> 00:55:20,439 Speaker 1: if the Higgs field got kicked off that shelf and 1054 00:55:20,480 --> 00:55:23,799 Speaker 1: relaxed down to a lower level, then the electron would 1055 00:55:23,800 --> 00:55:27,120 Speaker 1: have less mass or zero mass, the proton, the corks 1056 00:55:27,160 --> 00:55:29,840 Speaker 1: would have less mass or zero mass. All the fundamental 1057 00:55:29,880 --> 00:55:33,240 Speaker 1: particles could have different masses, and that includes the force 1058 00:55:33,320 --> 00:55:36,239 Speaker 1: carrying particles like the W and the z boson, which 1059 00:55:36,280 --> 00:55:39,160 Speaker 1: affect the strength of the forces. So like the reason 1060 00:55:39,200 --> 00:55:42,120 Speaker 1: the weak force is so weak is because the W 1061 00:55:42,239 --> 00:55:45,080 Speaker 1: N Z boson that carry it are so heavy. Because 1062 00:55:45,120 --> 00:55:48,040 Speaker 1: the Higgs field is stuck where it is, so everything 1063 00:55:48,600 --> 00:55:51,640 Speaker 1: is hanging on the Higgs field, being stuck on this shelf, 1064 00:55:52,080 --> 00:55:53,719 Speaker 1: and if it gets down to a different shelf or 1065 00:55:53,760 --> 00:55:57,080 Speaker 1: falls off completely, space is totally different. I mean, it 1066 00:55:57,200 --> 00:56:00,080 Speaker 1: still follows laws of physics, but the laws of is 1067 00:56:00,120 --> 00:56:03,759 Speaker 1: if we've discovered a sort of emergent properties of all 1068 00:56:03,880 --> 00:56:07,000 Speaker 1: these assumptions, and if both changed, everything would be different 1069 00:56:07,200 --> 00:56:10,600 Speaker 1: and space would be almost unrecognizable. So yeah, crazy, but 1070 00:56:10,680 --> 00:56:13,759 Speaker 1: also true, and it's possible that that could happen. You know, 1071 00:56:13,840 --> 00:56:16,800 Speaker 1: we don't know what it takes to trigger the Higgs 1072 00:56:16,880 --> 00:56:19,000 Speaker 1: field to sort of collapse to what we call its 1073 00:56:19,000 --> 00:56:23,000 Speaker 1: true vacuum. Some people worry that, for example, collisions of 1074 00:56:23,040 --> 00:56:25,799 Speaker 1: particles that high energies lack are being done by some 1075 00:56:25,880 --> 00:56:30,840 Speaker 1: people in Switzerland, you know, not now actually during this pandemic. 1076 00:56:31,080 --> 00:56:35,760 Speaker 1: But those kind of situations could create um vacuum bubbles 1077 00:56:35,800 --> 00:56:38,560 Speaker 1: of the Higgs field, and those vacuum bubbles would expand 1078 00:56:38,600 --> 00:56:41,120 Speaker 1: at the speed of light and pass through all space, 1079 00:56:41,600 --> 00:56:44,160 Speaker 1: and so we could end up collapsing the Higgs vacuum 1080 00:56:44,200 --> 00:56:47,120 Speaker 1: and changing the way space works, and you would still 1081 00:56:47,160 --> 00:56:50,120 Speaker 1: have physics. You would just have very very different physics 1082 00:56:50,239 --> 00:56:52,640 Speaker 1: that we would you know, we wouldn't be around to 1083 00:56:52,800 --> 00:56:54,520 Speaker 1: explore it. But somebody would have a lot of fun 1084 00:56:54,560 --> 00:56:58,279 Speaker 1: figuring out what the rules of that space are. I 1085 00:56:58,280 --> 00:57:00,719 Speaker 1: think there's there's another fascinating as it's of space, which 1086 00:57:00,760 --> 00:57:03,000 Speaker 1: is sort of hard to grapple with. Which is so 1087 00:57:03,160 --> 00:57:06,800 Speaker 1: the relationship between space and stuff, Like we think about 1088 00:57:07,120 --> 00:57:10,960 Speaker 1: stuff as in space. It's like moving through space. Spaces 1089 00:57:11,000 --> 00:57:12,879 Speaker 1: like there for you to be in, like the way 1090 00:57:12,880 --> 00:57:15,759 Speaker 1: a car is on a road. Right, But if you 1091 00:57:16,040 --> 00:57:19,720 Speaker 1: are serious about space having quantum fields in it, and 1092 00:57:19,840 --> 00:57:23,720 Speaker 1: all particles are just excitations of those quantum fields, then 1093 00:57:24,040 --> 00:57:27,400 Speaker 1: stuff is really just a property of space, right, Like 1094 00:57:28,200 --> 00:57:31,560 Speaker 1: if space is just like a big quantum field, then 1095 00:57:31,600 --> 00:57:33,320 Speaker 1: you know, you imagine your road is like a bigger 1096 00:57:33,360 --> 00:57:35,960 Speaker 1: rubber band, and a car on the road is like, okay, 1097 00:57:36,040 --> 00:57:38,960 Speaker 1: this part of the rubber band is bouncing, has it's excited, 1098 00:57:39,600 --> 00:57:41,760 Speaker 1: and then as the car moves down the road, it's 1099 00:57:41,800 --> 00:57:45,880 Speaker 1: not like you move that car. Instead, that energy gets 1100 00:57:45,880 --> 00:57:48,400 Speaker 1: transported to a new part of space, which then has 1101 00:57:48,480 --> 00:57:51,480 Speaker 1: the bounces. So it's like every time you move from 1102 00:57:51,520 --> 00:57:54,360 Speaker 1: one piece of space to another, it's like star Trek teleporter. 1103 00:57:54,560 --> 00:57:58,200 Speaker 1: It's not actually the same particles, right, It's like the 1104 00:57:58,240 --> 00:58:02,360 Speaker 1: information is being transmitted, so you can excite that new 1105 00:58:02,360 --> 00:58:04,840 Speaker 1: bit of space in the same way. But is it 1106 00:58:04,920 --> 00:58:06,800 Speaker 1: at least still you you know, it's all ship of 1107 00:58:06,880 --> 00:58:11,080 Speaker 1: theses stuff. And so when I slide from over here 1108 00:58:11,120 --> 00:58:14,160 Speaker 1: over here with the space isn't changing. It's just like 1109 00:58:14,320 --> 00:58:17,520 Speaker 1: different parts of space are getting excited and so, and 1110 00:58:17,600 --> 00:58:20,280 Speaker 1: that's the way. We are all sort of part of space. 1111 00:58:20,400 --> 00:58:22,840 Speaker 1: We're not in it, we are part of it. This 1112 00:58:22,880 --> 00:58:26,920 Speaker 1: almost seems like a sort of deeper reformulation of the 1113 00:58:26,960 --> 00:58:29,240 Speaker 1: ether idea, right, like that they used to think that 1114 00:58:29,280 --> 00:58:33,280 Speaker 1: there needed to be a uh, substance in space that 1115 00:58:33,520 --> 00:58:38,080 Speaker 1: electromagnetic radiation would propagate through, and then that was considered obsolete. 1116 00:58:38,120 --> 00:58:41,680 Speaker 1: But maybe is space itself in a way that substance 1117 00:58:41,720 --> 00:58:45,080 Speaker 1: that everything propagates through. Yeah, yeah, I mean that we're 1118 00:58:45,120 --> 00:58:47,320 Speaker 1: discovering all sorts of new forms of ether, like dark 1119 00:58:47,440 --> 00:58:50,360 Speaker 1: energy and a cosmological constant in the Higgs field, and 1120 00:58:50,400 --> 00:58:53,880 Speaker 1: like there are these things that that fill the universe 1121 00:58:54,360 --> 00:58:59,040 Speaker 1: with stuff with with something with some physical dynamical object 1122 00:58:59,560 --> 00:59:02,000 Speaker 1: and so, right, it used to be ridiculous to imagine 1123 00:59:02,280 --> 00:59:04,520 Speaker 1: that space was filled with something, and now it turns 1124 00:59:04,560 --> 00:59:12,000 Speaker 1: out space is everything, right cool, um, it is it 1125 00:59:12,120 --> 00:59:14,760 Speaker 1: is very cool. Alright. So we talked about several other 1126 00:59:14,840 --> 00:59:18,200 Speaker 1: properties of space, but one that we're wondering about now 1127 00:59:18,320 --> 00:59:20,720 Speaker 1: is how many ways does it go? You know, so 1128 00:59:21,040 --> 00:59:24,280 Speaker 1: you gotta got up and down, left, right, back and forth. 1129 00:59:24,480 --> 00:59:27,200 Speaker 1: And we know that. Uh. Now, we generally think of 1130 00:59:27,280 --> 00:59:30,720 Speaker 1: time as another dimension of space. Space time that they're 1131 00:59:30,760 --> 00:59:33,479 Speaker 1: they're sort of combined there. But does it stop there 1132 00:59:33,680 --> 00:59:37,040 Speaker 1: or is it reasonable to think about additional directions that 1133 00:59:37,120 --> 00:59:39,840 Speaker 1: you could go in that are not even conceivable to 1134 00:59:40,080 --> 00:59:43,600 Speaker 1: us in our you know, macroscopic movements. I think what 1135 00:59:43,720 --> 00:59:45,760 Speaker 1: physics has taught us over the last time of years 1136 00:59:45,960 --> 00:59:48,680 Speaker 1: is that every crazy idea is reasonable to think about 1137 00:59:48,840 --> 00:59:51,439 Speaker 1: for a few moments, and some of them will turn 1138 00:59:51,440 --> 00:59:53,520 Speaker 1: out to be true. And this is one of my 1139 00:59:53,600 --> 00:59:57,440 Speaker 1: favorite questions, is like how many dimensions are there to space? 1140 00:59:57,560 --> 00:59:59,640 Speaker 1: And I think you can start from just like, well, 1141 00:59:59,640 --> 01:00:02,320 Speaker 1: why would there be three? You know, like three is 1142 01:00:02,320 --> 01:00:06,240 Speaker 1: a weird number. You know, it's uh, whenever you find 1143 01:00:06,280 --> 01:00:08,560 Speaker 1: something about the universe and has a number, and you've 1144 01:00:08,560 --> 01:00:11,160 Speaker 1: got to ask, like why that number? If you ask, 1145 01:00:11,240 --> 01:00:14,240 Speaker 1: like mathematicians, what like deep numbers do you expect to 1146 01:00:14,280 --> 01:00:16,240 Speaker 1: see in a description of the universe? You know, they'll 1147 01:00:16,280 --> 01:00:19,840 Speaker 1: say one or pie or e, but nobody says three, 1148 01:00:20,280 --> 01:00:22,680 Speaker 1: right unless they're Catholic and think that the trinity has 1149 01:00:22,760 --> 01:00:25,480 Speaker 1: really insight into the fundamental nature of reality. And hey, 1150 01:00:25,520 --> 01:00:28,080 Speaker 1: you know, maybe they're right. But that's like clue number one. 1151 01:00:28,120 --> 01:00:31,280 Speaker 1: It's like, is there something three ish about the universe? 1152 01:00:31,440 --> 01:00:34,160 Speaker 1: Like that's kind of weird, but maybe it is. But 1153 01:00:34,600 --> 01:00:36,480 Speaker 1: it turns out that there's no reason to think that 1154 01:00:36,520 --> 01:00:39,400 Speaker 1: the universe couldn't have more dimensions. And you know what 1155 01:00:39,520 --> 01:00:42,280 Speaker 1: that would mean is like another way to move, Like 1156 01:00:42,520 --> 01:00:46,080 Speaker 1: you write your position in spaces, you know x y Z, right, 1157 01:00:46,360 --> 01:00:49,520 Speaker 1: you would just have another coordinate system. And the first 1158 01:00:49,560 --> 01:00:52,080 Speaker 1: thought you might have is like, well where would it go? Right, 1159 01:00:52,200 --> 01:00:55,120 Speaker 1: Like where do you put it? You can't, like X 1160 01:00:55,240 --> 01:00:57,760 Speaker 1: y Z seems to describe everything. Where would it be? 1161 01:00:58,400 --> 01:01:00,400 Speaker 1: And you have to it's really hard to think it 1162 01:01:00,520 --> 01:01:02,320 Speaker 1: higher dimensions. So you have to do this trick where 1163 01:01:02,360 --> 01:01:04,880 Speaker 1: you think in two D and extrapolate the three D 1164 01:01:04,960 --> 01:01:07,360 Speaker 1: because your mind can handle both of them, and then 1165 01:01:07,720 --> 01:01:10,240 Speaker 1: try to use that three D that extrapolation to go 1166 01:01:10,320 --> 01:01:12,920 Speaker 1: from three to four. Right, So when you think about 1167 01:01:12,920 --> 01:01:14,439 Speaker 1: two D, you like on the surface of a piece 1168 01:01:14,480 --> 01:01:17,880 Speaker 1: of paper, three D you're like a cube. So imagine 1169 01:01:17,880 --> 01:01:20,840 Speaker 1: moving that piece of paper through three dimensional space and 1170 01:01:20,840 --> 01:01:22,840 Speaker 1: thinking about what that would be like as you like 1171 01:01:23,040 --> 01:01:26,400 Speaker 1: interact with the three D objects. A sphere passing through 1172 01:01:26,560 --> 01:01:28,720 Speaker 1: a piece of paper would look like a dot that 1173 01:01:28,760 --> 01:01:30,920 Speaker 1: grows to a circle and then shrinks again to a 1174 01:01:30,960 --> 01:01:33,520 Speaker 1: dot and disappears. So in that same way, you can 1175 01:01:33,560 --> 01:01:36,320 Speaker 1: imagine four D objects in three D space. And so 1176 01:01:36,360 --> 01:01:38,600 Speaker 1: you use that sort of mental exercise to imagine like 1177 01:01:39,080 --> 01:01:42,040 Speaker 1: what these other dimensions could be like. And but it 1178 01:01:42,080 --> 01:01:44,600 Speaker 1: turns out that that the current theories of physics don't 1179 01:01:44,600 --> 01:01:48,080 Speaker 1: imagine these other dimensions being like these first three that 1180 01:01:48,120 --> 01:01:50,959 Speaker 1: wouldn't be infinite dimensions that you could go like there's 1181 01:01:50,960 --> 01:01:52,680 Speaker 1: no limit to how far you can go and X 1182 01:01:52,760 --> 01:01:55,600 Speaker 1: or y or z. But these other dimensions, if they 1183 01:01:55,600 --> 01:01:58,560 Speaker 1: were infinite, we probably would have noticed them already. So 1184 01:01:58,680 --> 01:02:02,040 Speaker 1: if they exist, they would be compactified. They would be 1185 01:02:02,080 --> 01:02:04,800 Speaker 1: like rolled up like instead of being infinite, there would 1186 01:02:04,800 --> 01:02:06,920 Speaker 1: be curved like we talked about before, and they might 1187 01:02:06,920 --> 01:02:10,200 Speaker 1: just be like a centimeter wide, and you know what 1188 01:02:10,240 --> 01:02:12,200 Speaker 1: that means. It's like, Okay, you have x, y, z, 1189 01:02:12,280 --> 01:02:15,080 Speaker 1: and then you have another number which varies between you know, 1190 01:02:15,240 --> 01:02:19,720 Speaker 1: zero and one centimeter, And it's actually quite a natural idea. 1191 01:02:20,360 --> 01:02:23,160 Speaker 1: If it's true, it would explain a lot of mysteries 1192 01:02:23,200 --> 01:02:25,760 Speaker 1: of the universe. Like in the in the nineties, I 1193 01:02:25,760 --> 01:02:27,760 Speaker 1: remember when this happened, people came up with this idea 1194 01:02:27,800 --> 01:02:30,560 Speaker 1: that we might have um extra dimensions of space of 1195 01:02:30,640 --> 01:02:34,880 Speaker 1: time to explain why gravity is so weak. Like you 1196 01:02:34,920 --> 01:02:37,680 Speaker 1: know that we have these basic forces of the universe, 1197 01:02:38,200 --> 01:02:41,360 Speaker 1: the electromagnetic force, the weak force, the strong force. They're 1198 01:02:41,400 --> 01:02:44,400 Speaker 1: all pretty powerful compared to gravity. Gravity is like ten 1199 01:02:44,480 --> 01:02:47,800 Speaker 1: to the thirty times weaker in comparison. And that's weird. 1200 01:02:47,880 --> 01:02:53,160 Speaker 1: Why can't we jump at all? And and that's weird right, 1201 01:02:53,200 --> 01:02:56,000 Speaker 1: Like if you hold a little magnet above the Earth, 1202 01:02:56,320 --> 01:02:59,440 Speaker 1: you have the entire gravitational force of the Earth, right 1203 01:02:59,560 --> 01:03:02,560 Speaker 1: is being outpowered by a tiny little fridge magnet. Right, 1204 01:03:02,800 --> 01:03:05,840 Speaker 1: it's pretty impressive. Um, so we wonder like why is 1205 01:03:05,880 --> 01:03:08,040 Speaker 1: gravity is so weak? And then we thought, well, maybe 1206 01:03:08,320 --> 01:03:11,880 Speaker 1: gravity isn't actually so weak. It's just that most of 1207 01:03:11,920 --> 01:03:16,280 Speaker 1: gravity sort of leaking out into these other dimensions because 1208 01:03:16,280 --> 01:03:18,760 Speaker 1: the strength of gravity depends on how many dimensions there are. 1209 01:03:19,480 --> 01:03:22,600 Speaker 1: Like you know, as space grows, as you get further 1210 01:03:22,600 --> 01:03:25,480 Speaker 1: away from something the sort of same amount of gravitational 1211 01:03:25,520 --> 01:03:29,120 Speaker 1: power spreads out through that dimensional space. So space was 1212 01:03:29,160 --> 01:03:32,280 Speaker 1: four or five or six dimensional, gravity would be weaker, right, 1213 01:03:32,760 --> 01:03:36,520 Speaker 1: And so they imagine that maybe space does have more 1214 01:03:36,560 --> 01:03:39,600 Speaker 1: dimensions and that gravity is actually really strong, and these 1215 01:03:39,600 --> 01:03:42,480 Speaker 1: dimensions are really really short and anywhere past like a 1216 01:03:42,560 --> 01:03:45,840 Speaker 1: centimeter distant, what you're feeling is gravity being weakened because 1217 01:03:45,840 --> 01:03:48,880 Speaker 1: it's spread out in these other dimensions. So that was 1218 01:03:48,920 --> 01:03:51,800 Speaker 1: the idea. It's sort of cool insight. I love when 1219 01:03:51,800 --> 01:03:55,600 Speaker 1: you have like an idea that requires you to revolutionize 1220 01:03:55,600 --> 01:03:58,160 Speaker 1: the way you think about the universe and solves an 1221 01:03:58,160 --> 01:04:01,120 Speaker 1: existing puzzle. Um that was the idea, and it was 1222 01:04:01,200 --> 01:04:04,840 Speaker 1: especially tantalizing because they realized nobody had checked, like what 1223 01:04:05,160 --> 01:04:07,600 Speaker 1: is the gravitational force between two things that are just 1224 01:04:07,640 --> 01:04:10,600 Speaker 1: a centimeter apart? And they realized, oh my gosh, nobody's 1225 01:04:10,600 --> 01:04:13,680 Speaker 1: actually done that experiment. We didn't even know. And the 1226 01:04:13,720 --> 01:04:16,720 Speaker 1: reason is that it's hard, like what's the gravitational force 1227 01:04:16,800 --> 01:04:20,720 Speaker 1: between two marbles? Almost nothing, So it takes like real 1228 01:04:20,880 --> 01:04:25,040 Speaker 1: experimental bravado to set up the test to test gravity 1229 01:04:25,160 --> 01:04:29,160 Speaker 1: really really short distances. And so they did that, and 1230 01:04:29,200 --> 01:04:31,040 Speaker 1: they've done a bunch of these cool experiments in the 1231 01:04:31,120 --> 01:04:35,360 Speaker 1: University of Washington testing really really isolated situations, and they 1232 01:04:35,360 --> 01:04:38,000 Speaker 1: found that gravity doesn't seem to get any stronger as 1233 01:04:38,040 --> 01:04:41,080 Speaker 1: you bring things really really close together. And then we 1234 01:04:41,120 --> 01:04:44,520 Speaker 1: tried to discover these extra dimensions at the particle colliders, 1235 01:04:44,560 --> 01:04:47,160 Speaker 1: of course, because we use particle colliders for everything, you know, 1236 01:04:47,440 --> 01:04:49,800 Speaker 1: test the fundamental theories of the universe and new new 1237 01:04:49,880 --> 01:04:52,000 Speaker 1: new dimensions and you know, clean your laundry and all 1238 01:04:52,040 --> 01:04:56,480 Speaker 1: sorts of stuff. And the idea is that if gravity 1239 01:04:56,520 --> 01:04:59,080 Speaker 1: gets really strong when things get closed up, then maybe 1240 01:04:59,080 --> 01:05:02,720 Speaker 1: when proton get smashed together, you could create little mini 1241 01:05:02,800 --> 01:05:06,880 Speaker 1: black holes. Because if gravity is really powerful as short distances, 1242 01:05:07,040 --> 01:05:09,919 Speaker 1: then even the really low mass stuff like protons might 1243 01:05:10,000 --> 01:05:13,120 Speaker 1: have enough energy to create black holes. And that's what 1244 01:05:13,240 --> 01:05:15,400 Speaker 1: you know, there's a whole hull baloo about whether or 1245 01:05:15,440 --> 01:05:19,280 Speaker 1: not the particle collider was going to destroy the world. Um, 1246 01:05:19,400 --> 01:05:22,480 Speaker 1: and that's one reason why people thought maybe it could happen, 1247 01:05:22,600 --> 01:05:25,480 Speaker 1: is that we might create these black holes, which would 1248 01:05:25,600 --> 01:05:28,280 Speaker 1: prove that there are extra dimensions and explain why gravity 1249 01:05:29,000 --> 01:05:31,840 Speaker 1: is so weak, and then also you know, eat the 1250 01:05:31,840 --> 01:05:34,880 Speaker 1: Earth and end the human race. But it turns out 1251 01:05:34,920 --> 01:05:37,680 Speaker 1: that we haven't seen any of those black holes. And 1252 01:05:37,840 --> 01:05:40,480 Speaker 1: also we're pretty confident that that we're not going to 1253 01:05:40,520 --> 01:05:42,920 Speaker 1: be creating a dangerous black holes. That's certain because there 1254 01:05:42,960 --> 01:05:45,440 Speaker 1: are other collisions that happen all the time, very high 1255 01:05:45,560 --> 01:05:49,480 Speaker 1: energy collisions from space that create the same configurations and 1256 01:05:49,560 --> 01:05:51,760 Speaker 1: haven't yet created a black hole to eat the Earth. 1257 01:05:51,920 --> 01:05:53,960 Speaker 1: So we thought that was safe. But we didn't see 1258 01:05:54,000 --> 01:05:56,440 Speaker 1: these black holes, which would have proven to us that 1259 01:05:56,480 --> 01:05:59,880 Speaker 1: there were extra dimensions, and so currently we don't know 1260 01:06:00,120 --> 01:06:02,200 Speaker 1: if there are other dimensions to space like we think 1261 01:06:02,240 --> 01:06:04,600 Speaker 1: there might be. It still could be possible. They would 1262 01:06:04,600 --> 01:06:07,240 Speaker 1: just have to be smaller than about a millimeter, but 1263 01:06:07,360 --> 01:06:09,360 Speaker 1: we haven't seen them and we don't have any evidence 1264 01:06:09,360 --> 01:06:12,000 Speaker 1: that they exist. But there are some theories that like them, 1265 01:06:12,000 --> 01:06:14,640 Speaker 1: like Strength theory would love if there were eleven or 1266 01:06:14,680 --> 01:06:17,800 Speaker 1: twenty six dimensions, but at this point we sort of 1267 01:06:17,840 --> 01:06:20,360 Speaker 1: haven't seen them until we build that you know, trillion 1268 01:06:20,400 --> 01:06:23,720 Speaker 1: dollar galaxy sized particle collider. Well, it looks like we're 1269 01:06:23,800 --> 01:06:27,080 Speaker 1: running out of time here, Daniel. You're you and Jore 1270 01:06:27,200 --> 01:06:31,080 Speaker 1: are still actively putting out episodes of the podcast. Can 1271 01:06:31,120 --> 01:06:33,080 Speaker 1: you give us just a brief idea of like what 1272 01:06:33,240 --> 01:06:34,880 Speaker 1: is out right now and what's coming out in the 1273 01:06:34,880 --> 01:06:37,920 Speaker 1: immediate future. Yeah, we're putting out episodes of Daniel and 1274 01:06:38,000 --> 01:06:41,440 Speaker 1: Jorge Explain the Universe twice a week. Recent topics include 1275 01:06:41,480 --> 01:06:44,160 Speaker 1: like could dark matter be made out of quarks? Or 1276 01:06:44,320 --> 01:06:47,320 Speaker 1: what's the cosmological constant? Or We've been doing a really 1277 01:06:47,360 --> 01:06:51,440 Speaker 1: fun series on analyzing the science of science fiction universes 1278 01:06:51,440 --> 01:06:54,240 Speaker 1: where we interview famous science fiction authors and ask them 1279 01:06:54,400 --> 01:06:58,240 Speaker 1: nitpicky physics questions about their wormholes and their warp drives. 1280 01:06:58,600 --> 01:07:00,840 Speaker 1: So we're having a lot of fun and we answer 1281 01:07:00,920 --> 01:07:02,960 Speaker 1: a lot of listener emails. We had a whole episode 1282 01:07:02,960 --> 01:07:05,760 Speaker 1: recently where we just went through listener questions and answered 1283 01:07:05,960 --> 01:07:08,480 Speaker 1: all of their questions from seven year olds to seventy 1284 01:07:08,520 --> 01:07:11,280 Speaker 1: seven year olds. Sorry, I just had a glance at 1285 01:07:11,280 --> 01:07:12,760 Speaker 1: the I was glanced into the episode list to see 1286 01:07:12,760 --> 01:07:15,200 Speaker 1: if I was particularly familiar with any of the authors. 1287 01:07:15,200 --> 01:07:18,000 Speaker 1: So that you've you've talked to thus far y'all doing? Uh, 1288 01:07:18,080 --> 01:07:21,280 Speaker 1: Kim Stanley Robinson by by chance? No, we have it yet, 1289 01:07:21,360 --> 01:07:23,760 Speaker 1: but we've talked to Bray Crouch. Should we talk to 1290 01:07:23,880 --> 01:07:27,400 Speaker 1: Hugh Award winning authors like Ann Lecky and Mary Robin 1291 01:07:27,480 --> 01:07:31,840 Speaker 1: and Cole and Becky Chambers um, it's been really fascinating 1292 01:07:31,880 --> 01:07:34,320 Speaker 1: to see, like, how do you build the science fiction universe? 1293 01:07:34,320 --> 01:07:36,360 Speaker 1: At what point do you stop worrying about getting the 1294 01:07:36,360 --> 01:07:39,520 Speaker 1: science right and just think about the story. And then also, 1295 01:07:39,560 --> 01:07:41,680 Speaker 1: for me, since I'm such a science fiction buff, I 1296 01:07:41,720 --> 01:07:43,320 Speaker 1: just get a fanboy a little bit and talk to 1297 01:07:43,360 --> 01:07:46,080 Speaker 1: all these famous people. This might be too loaded of 1298 01:07:46,120 --> 01:07:51,240 Speaker 1: a question, but if you could interview a now deceased 1299 01:07:51,280 --> 01:07:54,200 Speaker 1: science fiction author and asked them some of these same questions, 1300 01:07:54,360 --> 01:07:59,040 Speaker 1: which one would you choose? You know, until I learned 1301 01:07:59,040 --> 01:08:01,000 Speaker 1: that he was also a jerk, I would have loved 1302 01:08:01,000 --> 01:08:05,400 Speaker 1: to interview Isaac Asimov because he created not just you know, 1303 01:08:05,480 --> 01:08:09,120 Speaker 1: new technology fiction, but like his Foundation series where he 1304 01:08:09,160 --> 01:08:12,720 Speaker 1: creates like actually a new field of science in his 1305 01:08:12,840 --> 01:08:16,080 Speaker 1: prediction of the future. Um, I thought that was really fascinating. 1306 01:08:16,080 --> 01:08:18,920 Speaker 1: I would love to just understand the kind of development 1307 01:08:18,920 --> 01:08:21,320 Speaker 1: of that idea and how he built a story around it. 1308 01:08:21,760 --> 01:08:24,639 Speaker 1: But then it turns out, like many greats from the past, 1309 01:08:24,720 --> 01:08:26,680 Speaker 1: he was also a jerk to lots of people he 1310 01:08:26,760 --> 01:08:29,439 Speaker 1: worked with. All right, well, well, thanks again for for 1311 01:08:29,479 --> 01:08:31,240 Speaker 1: coming on the show and chatting with us, And yeah, 1312 01:08:31,280 --> 01:08:33,960 Speaker 1: we encourage our listeners to check out those episodes and 1313 01:08:34,080 --> 01:08:36,439 Speaker 1: uh you know, and and hang with us. Thanks for 1314 01:08:36,720 --> 01:08:39,120 Speaker 1: calling in from your closet to talk with us. As 1315 01:08:39,160 --> 01:08:42,000 Speaker 1: we call in from our closets, don't expand out of 1316 01:08:42,000 --> 01:08:44,559 Speaker 1: reach before the next time we get to have you on. 1317 01:08:44,960 --> 01:08:46,560 Speaker 1: I hope I'll still fit in my pants by the 1318 01:08:46,640 --> 01:08:48,760 Speaker 1: next time I talk to you, guys. Thanks very much 1319 01:08:48,760 --> 01:08:51,519 Speaker 1: for having me on. All right, thank you, Thanks Daniel. 1320 01:08:51,880 --> 01:08:53,760 Speaker 1: In the meantime, if you want to check out other 1321 01:08:53,760 --> 01:08:56,600 Speaker 1: episodes of Stuff to Boil your Mind, head over to 1322 01:08:56,840 --> 01:08:58,760 Speaker 1: stuff to Boil your Mind dot com. That'll shoot you 1323 01:08:58,760 --> 01:09:00,640 Speaker 1: over to the I Heart listing for this show. But 1324 01:09:00,760 --> 01:09:04,160 Speaker 1: ultimately you can find our podcast wherever you get your 1325 01:09:04,200 --> 01:09:07,200 Speaker 1: podcasts and wherever that happens to be. Just make sure 1326 01:09:07,200 --> 01:09:11,080 Speaker 1: you rate, review, and subscribe huge thanks as always to 1327 01:09:11,120 --> 01:09:14,439 Speaker 1: our excellent audio producer Seth Nicholas Johnson. If you would 1328 01:09:14,479 --> 01:09:16,240 Speaker 1: like to get in touch with us with feedback on 1329 01:09:16,280 --> 01:09:18,360 Speaker 1: this episode or any other, to suggest a topic for 1330 01:09:18,400 --> 01:09:20,759 Speaker 1: the future, or just to say hi, you can email 1331 01:09:20,840 --> 01:09:31,720 Speaker 1: us at contact at stuff to Blow your Mind dot com. 1332 01:09:31,800 --> 01:09:34,280 Speaker 1: Stuff to Blow Your Mind is production of I Heart Radio. 1333 01:09:34,640 --> 01:09:36,960 Speaker 1: For more podcasts for my Heart Radio, this the iHeart 1334 01:09:37,040 --> 01:09:39,760 Speaker 1: Radio app Apple Podcasts or wherever you're listening to your 1335 01:09:39,800 --> 01:09:49,120 Speaker 1: favorite shows,