1 00:00:05,800 --> 00:00:09,280 Speaker 1: Inside space? Is there a place where the matter ends 2 00:00:09,320 --> 00:00:13,240 Speaker 1: and it's just empty space? And then path that space? 3 00:00:13,680 --> 00:00:16,639 Speaker 1: Is there something else that's not space? Can space have 4 00:00:16,680 --> 00:00:19,360 Speaker 1: an edge? Right? And so that to me is the 5 00:00:19,800 --> 00:00:22,560 Speaker 1: is this concept of the universe all the matter in 6 00:00:22,640 --> 00:00:25,280 Speaker 1: all the space, Okay, things beyond that space? If there 7 00:00:25,320 --> 00:00:27,880 Speaker 1: is anything there I would consider not part of our universe. 8 00:00:27,960 --> 00:00:29,800 Speaker 2: Oh I see, So we could like there could be 9 00:00:29,920 --> 00:00:32,080 Speaker 2: through stuff and maybe at some point we run out 10 00:00:32,080 --> 00:00:35,040 Speaker 2: of stuff there, but there's still there could still be space. 11 00:00:35,040 --> 00:00:51,879 Speaker 1: There could still be space. Hi. I'm Daniel and I'm Horehane, 12 00:00:52,440 --> 00:00:55,120 Speaker 1: and we're here to explain the universe. 13 00:00:55,480 --> 00:00:58,040 Speaker 2: Today we're going to talk about the biggest question in 14 00:00:58,040 --> 00:00:58,960 Speaker 2: the universe. 15 00:00:58,840 --> 00:01:01,560 Speaker 1: The biggest question you could even possibly imagine. 16 00:01:04,120 --> 00:01:06,360 Speaker 2: How big is the universe? 17 00:01:07,120 --> 00:01:09,319 Speaker 1: Like really, how big is it? Like? Does it go 18 00:01:09,400 --> 00:01:12,120 Speaker 1: on forever? Is it just a little bit bigger than 19 00:01:12,120 --> 00:01:14,600 Speaker 1: we can see? Does it wrap around on itself? Is 20 00:01:14,640 --> 00:01:17,240 Speaker 1: it some other crazy thing? That's what we are going 21 00:01:17,280 --> 00:01:19,480 Speaker 1: to try to tackle today. We went out in the 22 00:01:19,480 --> 00:01:21,400 Speaker 1: street and we asked people what they thought about this 23 00:01:21,680 --> 00:01:23,560 Speaker 1: the biggest of questions. 24 00:01:24,319 --> 00:01:27,840 Speaker 3: Oh man, it's pretty big, Like I'm pretty sure it's 25 00:01:27,880 --> 00:01:31,160 Speaker 3: like unmeasurable because like we don't really know much about it. 26 00:01:31,480 --> 00:01:33,800 Speaker 3: So I'm pretty I wanna say, like pretty big, like 27 00:01:33,880 --> 00:01:35,440 Speaker 3: it's really unmeasurable. 28 00:01:35,920 --> 00:01:38,800 Speaker 1: Tend to the something particles. I don't know, do you 29 00:01:38,840 --> 00:01:41,560 Speaker 1: want like a number or whatever you think is appropriate. 30 00:01:42,920 --> 00:01:45,000 Speaker 2: I remember reading some of where that's like it's always growing, 31 00:01:45,120 --> 00:01:46,000 Speaker 2: so it's like infinite. 32 00:01:46,080 --> 00:01:49,240 Speaker 1: Right, So most people seem to feel like, wow, the 33 00:01:49,400 --> 00:01:52,360 Speaker 1: universe is pretty big, right. Some people thought it was 34 00:01:52,480 --> 00:01:55,880 Speaker 1: like infinite, and some people thought, m just just really big. 35 00:01:56,040 --> 00:01:57,040 Speaker 2: Nobody thought it was small. 36 00:01:58,640 --> 00:02:00,960 Speaker 1: Nobody's like I can see the end of it's just 37 00:02:00,960 --> 00:02:01,360 Speaker 1: about it. 38 00:02:02,360 --> 00:02:04,080 Speaker 2: It's only as far as I can see. 39 00:02:04,200 --> 00:02:06,560 Speaker 1: That's right, And ascually that's really interesting because I bet 40 00:02:06,600 --> 00:02:09,600 Speaker 1: like if you ask prehistoric man how big is the universe, 41 00:02:09,600 --> 00:02:11,640 Speaker 1: they would just like say, like, look around you, this 42 00:02:11,800 --> 00:02:14,560 Speaker 1: is what there is, and they couldn't even really imagine. 43 00:02:18,280 --> 00:02:20,400 Speaker 1: So let's break it down. There's all the stuff right 44 00:02:20,680 --> 00:02:24,400 Speaker 1: as particles. There's matter, right, you know, there's matter and 45 00:02:24,520 --> 00:02:25,080 Speaker 1: energy and all. 46 00:02:25,000 --> 00:02:28,200 Speaker 2: That stuff feel and touch and see mm hm. 47 00:02:28,280 --> 00:02:30,160 Speaker 1: But I think there's one other component which I think 48 00:02:30,240 --> 00:02:32,280 Speaker 1: is a little less usual for people to think about, 49 00:02:32,360 --> 00:02:33,520 Speaker 1: and that's the space. 50 00:02:34,040 --> 00:02:34,400 Speaker 2: Space. 51 00:02:34,960 --> 00:02:37,519 Speaker 1: I would think of the universe as all the stuff 52 00:02:37,880 --> 00:02:39,799 Speaker 1: and all the space that it's in. 53 00:02:40,160 --> 00:02:43,800 Speaker 2: Okay, space like the stuff we can actually move around in. 54 00:02:44,560 --> 00:02:47,600 Speaker 1: Yes, the place we can move around in the space 55 00:02:47,680 --> 00:02:48,080 Speaker 1: we have. 56 00:02:48,240 --> 00:02:51,440 Speaker 2: At some point that space ends. 57 00:02:51,919 --> 00:02:56,040 Speaker 1: Yeah, the space could end right now. Somebody out there listening, 58 00:02:56,280 --> 00:02:59,640 Speaker 1: you smart, good looking listener, you might be thinking, what 59 00:03:00,040 --> 00:03:02,600 Speaker 1: how good space possibly end? He's talking about space like 60 00:03:02,639 --> 00:03:05,120 Speaker 1: it's a thing, like it's water and the fish could 61 00:03:05,200 --> 00:03:07,640 Speaker 1: run into the end of it or something. But briefly, 62 00:03:07,639 --> 00:03:10,880 Speaker 1: we should just remind people that space is not just emptiness. 63 00:03:10,960 --> 00:03:13,440 Speaker 1: It's not just a backdrop. It's not just the nothing 64 00:03:13,919 --> 00:03:17,800 Speaker 1: in which stuff happens. It's stuff. It has properties. It 65 00:03:17,880 --> 00:03:20,360 Speaker 1: can bend and expand and ripple and do all sorts 66 00:03:20,360 --> 00:03:24,000 Speaker 1: of weird crazy stuff, and so we know that it's 67 00:03:24,040 --> 00:03:27,160 Speaker 1: a thing. It's a dynamic, physical thing that could do stuff. 68 00:03:27,440 --> 00:03:29,720 Speaker 1: So we have to consider the possibility that it ends. 69 00:03:29,720 --> 00:03:32,040 Speaker 1: Like that's part of the question how big is the universe? 70 00:03:32,120 --> 00:03:35,400 Speaker 1: Is how much space is there? And can it end? Right? 71 00:03:35,440 --> 00:03:38,800 Speaker 2: It's like we're fish and we're asking how big is 72 00:03:38,840 --> 00:03:39,680 Speaker 2: the ocean? 73 00:03:40,840 --> 00:03:44,800 Speaker 1: Yeah? Yeah, okay, exactly how big is the I wonder 74 00:03:44,840 --> 00:03:46,920 Speaker 1: do you think fish wonder about how big is the ocean. 75 00:03:47,960 --> 00:03:51,680 Speaker 2: I think fish wonder about not getting eaten by other 76 00:03:51,760 --> 00:03:54,520 Speaker 2: fish occupation. 77 00:03:55,200 --> 00:03:59,160 Speaker 1: Right, And fish might also wonder like are there other oceans? Right? 78 00:03:59,160 --> 00:04:01,160 Speaker 1: That's the multiverse for fishes. 79 00:04:02,680 --> 00:04:05,600 Speaker 2: But in our universe, you're saying space might have a 80 00:04:05,680 --> 00:04:10,840 Speaker 2: limit to it, like there might be an end to it. Yeah, 81 00:04:10,880 --> 00:04:12,920 Speaker 2: but so is it like a wall or is it 82 00:04:13,000 --> 00:04:15,560 Speaker 2: like a what does it mean for it to be 83 00:04:15,600 --> 00:04:16,520 Speaker 2: at the edge of space? 84 00:04:17,000 --> 00:04:19,599 Speaker 1: Well, there could be an edge to space, and to 85 00:04:19,640 --> 00:04:21,480 Speaker 1: think about what that means, we have to think about 86 00:04:21,480 --> 00:04:23,520 Speaker 1: what space is a little bit more like we have 87 00:04:23,520 --> 00:04:27,600 Speaker 1: to think about whether space can curve or if space 88 00:04:27,839 --> 00:04:31,000 Speaker 1: is flat right right, And this kind of stuff is 89 00:04:31,040 --> 00:04:33,359 Speaker 1: really hard to think about in three dimensions, like what 90 00:04:33,400 --> 00:04:37,640 Speaker 1: does it mean for space xyz space right xyz being 91 00:04:37,680 --> 00:04:41,000 Speaker 1: one two, three dimensions, The curve really hard to think 92 00:04:41,000 --> 00:04:43,359 Speaker 1: about because it's hard for us to think about that 93 00:04:43,600 --> 00:04:47,240 Speaker 1: about space curving in some higher dimensions. So usually it's 94 00:04:47,279 --> 00:04:49,680 Speaker 1: best if we think about it in two dimensions, so 95 00:04:49,680 --> 00:04:52,320 Speaker 1: we can think about it as curving in that third dimension. 96 00:04:52,440 --> 00:04:55,719 Speaker 1: So imagine that we are two dimensional scientists. We're like 97 00:04:55,800 --> 00:04:57,520 Speaker 1: living on a sheet of paper where we can only 98 00:04:57,560 --> 00:05:00,240 Speaker 1: move in two dimensions like X and y, and then 99 00:05:00,240 --> 00:05:02,800 Speaker 1: we can ask those two dimensional scientists can ask is 100 00:05:02,880 --> 00:05:06,200 Speaker 1: our space curved? Is our paper universe curved? 101 00:05:06,320 --> 00:05:06,920 Speaker 2: Right? 102 00:05:06,920 --> 00:05:09,800 Speaker 1: And that changes the answer, Like say you discover that 103 00:05:09,839 --> 00:05:13,360 Speaker 1: it is curved and it has a positive curvature. Positive 104 00:05:13,360 --> 00:05:15,640 Speaker 1: curvature would be like on the surface of a sphere 105 00:05:15,800 --> 00:05:19,320 Speaker 1: or a planet. Right, if it has positive curvature, that 106 00:05:19,360 --> 00:05:22,560 Speaker 1: has consequences for its shape, because if it's positively curved, 107 00:05:22,680 --> 00:05:26,000 Speaker 1: it can't go on forever, right, Like the Earth. You're 108 00:05:26,040 --> 00:05:28,640 Speaker 1: standing on the surface of the Earth and you know 109 00:05:28,720 --> 00:05:30,920 Speaker 1: the Earth is curved, and that means that Earth can't 110 00:05:30,960 --> 00:05:32,479 Speaker 1: be infinitely big, right. 111 00:05:32,880 --> 00:05:35,440 Speaker 2: Right, right, So you're saying, at the edge of the universe, 112 00:05:35,480 --> 00:05:39,320 Speaker 2: maybe the space space is curved. 113 00:05:38,400 --> 00:05:41,039 Speaker 1: Or maybe it's a possibility you have to consider that 114 00:05:41,080 --> 00:05:44,960 Speaker 1: maybe space is curved everywhere. If the universe had curved 115 00:05:45,000 --> 00:05:48,039 Speaker 1: space and it was positively curved, that would mean that 116 00:05:48,160 --> 00:05:51,840 Speaker 1: it could be sort of looped on itself very naturally, 117 00:05:51,960 --> 00:05:54,520 Speaker 1: the same way the surface of a planet is, and 118 00:05:54,600 --> 00:05:57,280 Speaker 1: you could travel around it through space and not really 119 00:05:57,320 --> 00:05:59,720 Speaker 1: get to the edge, right, Like where is the edge 120 00:05:59,760 --> 00:06:02,400 Speaker 1: of the Earth? Well, the Earth, the surface of the Earth, 121 00:06:02,440 --> 00:06:05,440 Speaker 1: a two dimensional surface doesn't have an edge. 122 00:06:05,760 --> 00:06:08,960 Speaker 2: Like people in electoric times. Maybe they saw the earth 123 00:06:09,000 --> 00:06:11,279 Speaker 2: around them and it thought, oh man, this is pretty big. 124 00:06:11,320 --> 00:06:13,760 Speaker 2: It probably goes on forever, but they didn't know that 125 00:06:14,080 --> 00:06:15,840 Speaker 2: actually the land curved. 126 00:06:16,800 --> 00:06:17,520 Speaker 1: That's right, And. 127 00:06:18,040 --> 00:06:19,880 Speaker 2: It turns out that we're actually kind of on this 128 00:06:20,040 --> 00:06:23,039 Speaker 2: sphere and if you keep going in one direction you 129 00:06:23,120 --> 00:06:24,040 Speaker 2: kind of loop back around. 130 00:06:24,920 --> 00:06:27,000 Speaker 1: That's right. Yeah, And it's not like you get to 131 00:06:27,000 --> 00:06:29,560 Speaker 1: the edge and you get magically transported back to where 132 00:06:29,560 --> 00:06:33,080 Speaker 1: you started or something. There's no you know, shortcut or 133 00:06:33,120 --> 00:06:35,679 Speaker 1: magic there on the surface of the earth. You keep walking, 134 00:06:35,760 --> 00:06:36,600 Speaker 1: you come back to where you. 135 00:06:36,560 --> 00:06:39,560 Speaker 2: Start, just connected back onto itself exactly. 136 00:06:39,640 --> 00:06:40,280 Speaker 1: That's the key. 137 00:06:40,400 --> 00:06:44,480 Speaker 2: So that's a space like space that we're in. Could 138 00:06:44,560 --> 00:06:46,480 Speaker 2: kind of like if you keep going in one direction 139 00:06:46,560 --> 00:06:48,719 Speaker 2: on a spaceship, you'll come back around to the same 140 00:06:48,760 --> 00:06:50,280 Speaker 2: spot exactly. 141 00:06:50,320 --> 00:06:52,560 Speaker 1: And the way you said it was perfect. It's the connection. 142 00:06:52,800 --> 00:06:56,359 Speaker 1: So we like to talk about space by using this 143 00:06:56,440 --> 00:06:59,039 Speaker 1: analogy of living in two dimensions and thinking about it 144 00:06:59,080 --> 00:07:02,160 Speaker 1: being curved in a dimension. Now pop that up to 145 00:07:02,240 --> 00:07:04,279 Speaker 1: three dimensions, right, because we know our space is at 146 00:07:04,400 --> 00:07:05,560 Speaker 1: least three dimensions. 147 00:07:05,600 --> 00:07:07,960 Speaker 2: Popping up and popping an asp rain because now I'm 148 00:07:07,960 --> 00:07:08,520 Speaker 2: getting ahead. 149 00:07:11,440 --> 00:07:13,760 Speaker 1: Did we work on getting Advilt to support this podcast 150 00:07:13,800 --> 00:07:15,840 Speaker 1: because we're sending them a lot of customers. 151 00:07:15,920 --> 00:07:18,400 Speaker 2: My god, that could be a great sponsor. 152 00:07:19,240 --> 00:07:24,080 Speaker 1: That's right. So pop that up into your three dimensional space, right, 153 00:07:24,280 --> 00:07:25,880 Speaker 1: and then you can ask, well, what does it mean 154 00:07:25,960 --> 00:07:29,480 Speaker 1: for three dimensional space to be curved? Well, it's not 155 00:07:29,960 --> 00:07:33,520 Speaker 1: that we imagine that it's curved in some other fourth dimension. 156 00:07:33,640 --> 00:07:36,200 Speaker 1: It's not that it's hanging in four dimensional space and 157 00:07:36,280 --> 00:07:39,560 Speaker 1: has a curvature in it. It's how the space is connected. 158 00:07:39,640 --> 00:07:43,320 Speaker 1: We call it intrinsic curvature because it reflects how one 159 00:07:43,400 --> 00:07:45,840 Speaker 1: part of space is connected to another part of space. 160 00:07:46,320 --> 00:07:49,040 Speaker 1: So without hanging in four dimensions, you can be connected 161 00:07:49,080 --> 00:07:51,320 Speaker 1: in a way that space is curved and you loop 162 00:07:51,400 --> 00:07:53,600 Speaker 1: back on yourself without ever really noticing. 163 00:07:53,800 --> 00:07:56,040 Speaker 2: So when we talk about the size of the universe, 164 00:07:56,200 --> 00:07:58,560 Speaker 2: we mean that it has maybe some kind of edge, 165 00:07:58,640 --> 00:08:01,120 Speaker 2: but maybe that edge is like how we think of 166 00:08:01,120 --> 00:08:03,800 Speaker 2: an edge as like a stub or a wall. Maybe 167 00:08:03,840 --> 00:08:05,960 Speaker 2: it's just kind of looped around, and so the size 168 00:08:05,960 --> 00:08:08,400 Speaker 2: of it is kind of like this blob of. 169 00:08:08,280 --> 00:08:13,520 Speaker 1: Space, right, yeah, exactly. And the possible answers for the 170 00:08:13,600 --> 00:08:16,600 Speaker 1: size of the universe depend on how it's curved. Right, 171 00:08:16,640 --> 00:08:20,160 Speaker 1: If it's positively curved, then it can only really be 172 00:08:20,320 --> 00:08:23,400 Speaker 1: like a big sphere, which means it's finite. Right if 173 00:08:23,440 --> 00:08:26,920 Speaker 1: it would have been negative. If it's not right, if 174 00:08:26,960 --> 00:08:31,200 Speaker 1: it's flat. If space is flat, like it doesn't curve intrinsically, 175 00:08:31,440 --> 00:08:34,120 Speaker 1: then it could potentially go on forever. If space is 176 00:08:34,280 --> 00:08:37,480 Speaker 1: negatively curved, that's like the shape of a saddle, it's 177 00:08:37,480 --> 00:08:40,000 Speaker 1: a negative curvature, then it could have all sorts of 178 00:08:40,040 --> 00:08:42,280 Speaker 1: really weird shapes, but it could still be infinite. 179 00:08:42,600 --> 00:08:45,880 Speaker 2: Okay, so the options are infinite or not infinite. 180 00:08:47,920 --> 00:08:50,880 Speaker 1: That pretty much categorizes the options for everything. How big 181 00:08:50,920 --> 00:08:53,280 Speaker 1: is your househoorg? Is it infinite or non infinite? I 182 00:08:53,280 --> 00:08:55,400 Speaker 1: want to see that option actually on Zillo from. 183 00:08:55,240 --> 00:08:58,960 Speaker 2: The Yeah, I would love to have infinite square feet 184 00:08:59,240 --> 00:09:01,240 Speaker 2: house because. 185 00:09:01,080 --> 00:09:01,680 Speaker 3: Then I. 186 00:09:03,400 --> 00:09:06,440 Speaker 1: Needed to look forever for your kid's shoes, Right, where'd 187 00:09:06,440 --> 00:09:08,560 Speaker 1: you put them? I put them in room number somewhere 188 00:09:08,559 --> 00:09:09,640 Speaker 1: between here and infinity. 189 00:09:09,920 --> 00:09:12,920 Speaker 2: Yeah. So let's talk about the possibilities of what could 190 00:09:12,960 --> 00:09:15,760 Speaker 2: be beyond the observable universe. I mean, we talked a 191 00:09:15,760 --> 00:09:18,559 Speaker 2: little bit about before about maybe it's infinite, maybe it's 192 00:09:18,559 --> 00:09:22,200 Speaker 2: not infinite. Do we really have no idea whether the 193 00:09:22,400 --> 00:09:26,439 Speaker 2: actual universe is just a little bit bigger than the 194 00:09:26,520 --> 00:09:30,520 Speaker 2: observable universe, much bigger than the observable universe, or it 195 00:09:30,559 --> 00:09:34,160 Speaker 2: could be infinite. We really have sort of no indication 196 00:09:34,320 --> 00:09:36,560 Speaker 2: of which possibility it is. 197 00:09:37,240 --> 00:09:40,080 Speaker 1: We have a few clues, they're kind of indirect, and 198 00:09:40,200 --> 00:09:42,120 Speaker 1: I want to talk about that some more, but first 199 00:09:42,200 --> 00:09:55,480 Speaker 1: let's take a quick break. One clue comes from the 200 00:09:55,559 --> 00:09:59,000 Speaker 1: curvature of space. We talked earlier about how the curvature 201 00:09:59,000 --> 00:10:01,440 Speaker 1: of space affects the how the size of the universe 202 00:10:01,480 --> 00:10:04,240 Speaker 1: could be. And if a space is curved positively or 203 00:10:04,320 --> 00:10:07,760 Speaker 1: negative or flat, that limits the options, right, So that's 204 00:10:07,760 --> 00:10:10,480 Speaker 1: something we can measure. We can measure it here. We 205 00:10:10,520 --> 00:10:13,840 Speaker 1: can look around us and measure how curved is space 206 00:10:13,960 --> 00:10:17,319 Speaker 1: in our universe. And that might be a bit of 207 00:10:17,360 --> 00:10:19,440 Speaker 1: a puzzler, right, like, how does that mean? How could 208 00:10:19,440 --> 00:10:23,120 Speaker 1: space be curved? How could you possibly measure it? And 209 00:10:23,200 --> 00:10:24,760 Speaker 1: to think about that, it's best to go back to 210 00:10:24,800 --> 00:10:27,200 Speaker 1: the two dimensional example. If you're living on the surface 211 00:10:27,240 --> 00:10:29,480 Speaker 1: of a planet. For example, if you were a two 212 00:10:29,520 --> 00:10:32,680 Speaker 1: dimensional scientist living on the surface of a planet or 213 00:10:32,800 --> 00:10:35,760 Speaker 1: some surface, and you wanted to know is this surface curved. 214 00:10:36,120 --> 00:10:39,280 Speaker 1: What you could do is make a triangle. Because triangles 215 00:10:39,360 --> 00:10:42,439 Speaker 1: are very sensitive to curvature. For example, you draw a 216 00:10:42,520 --> 00:10:44,920 Speaker 1: triangle in a sheet of paper, you add up the angles, 217 00:10:45,240 --> 00:10:47,760 Speaker 1: then you get one hundred and eighty degrees every triangle, 218 00:10:48,000 --> 00:10:51,280 Speaker 1: every flat surface, no matter what, beautiful. 219 00:10:50,840 --> 00:10:53,199 Speaker 2: Results in geometre, basic geometry. 220 00:10:53,679 --> 00:10:57,120 Speaker 1: That's right. Yeah, Now imagine that triangle sitting on the 221 00:10:57,160 --> 00:11:00,600 Speaker 1: surface of a tennis ball. You can draw triangle on 222 00:11:00,600 --> 00:11:03,240 Speaker 1: the surface of a tennis ball that has three right 223 00:11:03,280 --> 00:11:07,840 Speaker 1: angles on it, because triangles behave differently on a curved surface. 224 00:11:08,120 --> 00:11:11,160 Speaker 2: Yeah, it could imagine that could be ninety degrees, meaning 225 00:11:11,160 --> 00:11:13,360 Speaker 2: that it adds up to two hundred and seventy degrees. 226 00:11:13,800 --> 00:11:16,600 Speaker 1: Yeah, exactly. So let's take a break so everyone can 227 00:11:16,640 --> 00:11:18,960 Speaker 1: go get a tennis ball and a sharpie. You try 228 00:11:19,040 --> 00:11:21,000 Speaker 1: this at home, and we'll be right back when you 229 00:11:21,040 --> 00:11:24,360 Speaker 1: have your tennis ball, all right, Assuming you're holding a 230 00:11:24,360 --> 00:11:27,280 Speaker 1: tennis ball, yeah, and you've annoyed your partner or your 231 00:11:27,320 --> 00:11:30,080 Speaker 1: spouse or your child by drawing triangles on it. You 232 00:11:30,120 --> 00:11:33,000 Speaker 1: can see the triangles behave differently on a curved suraace. 233 00:11:33,080 --> 00:11:34,200 Speaker 2: It looks kind of bloated. 234 00:11:35,120 --> 00:11:37,520 Speaker 1: Yeah, yeah, it looks distorted. And so if you just 235 00:11:37,600 --> 00:11:39,760 Speaker 1: make a triangle and add up the angles, you can 236 00:11:39,800 --> 00:11:42,199 Speaker 1: see whether or not the space you're in is curved 237 00:11:42,360 --> 00:11:42,840 Speaker 1: or flat. 238 00:11:43,200 --> 00:11:44,880 Speaker 2: Is that kind of a great way to think about 239 00:11:45,040 --> 00:11:48,120 Speaker 2: the curvature space. It's kind of like a distortion of space. 240 00:11:48,760 --> 00:11:51,400 Speaker 1: Yes, Yes, it's a distortion and how the pieces of 241 00:11:51,440 --> 00:11:54,640 Speaker 1: space are connected to each other, which changes how you 242 00:11:54,679 --> 00:11:57,880 Speaker 1: move through space. Changes like how you can get from 243 00:11:57,880 --> 00:11:59,920 Speaker 1: one spot in space to another spot in space. 244 00:12:00,400 --> 00:12:02,880 Speaker 2: Yeah, like I think I'm going straight, but I'm actually 245 00:12:02,960 --> 00:12:04,440 Speaker 2: kind of being distorted in one way. 246 00:12:04,360 --> 00:12:07,560 Speaker 1: Or the other. Yeah, it changes what straight means. 247 00:12:07,920 --> 00:12:10,960 Speaker 2: Okay, So then the curvature might give some clues as 248 00:12:11,000 --> 00:12:13,920 Speaker 2: to whether, like we wrap around in ourselves or or 249 00:12:13,960 --> 00:12:17,959 Speaker 2: whether we don't. I mean, that's all it can tell us, right, 250 00:12:18,000 --> 00:12:20,400 Speaker 2: It's whether we're in a sphere or we're not in 251 00:12:20,440 --> 00:12:20,960 Speaker 2: a sphere. 252 00:12:21,240 --> 00:12:23,080 Speaker 1: Well, there's one other option, which is that we're on 253 00:12:23,080 --> 00:12:26,360 Speaker 1: a sort of a saddle if space is negatively curved. 254 00:12:26,679 --> 00:12:29,040 Speaker 1: Imagine you have a sheet of paper that's formed sort 255 00:12:29,040 --> 00:12:31,079 Speaker 1: of like a bowl, right the opposite of a sphere, 256 00:12:31,120 --> 00:12:33,080 Speaker 1: and you're in the middle of that bowl. You can 257 00:12:33,160 --> 00:12:36,200 Speaker 1: draw a triangle in that and it will have angles 258 00:12:36,240 --> 00:12:38,480 Speaker 1: of less than one hundred and eighty degrees. 259 00:12:39,000 --> 00:12:41,000 Speaker 2: You measure distortion. 260 00:12:41,800 --> 00:12:45,120 Speaker 1: Yeah, yeah, not quite a bowl because that's just the 261 00:12:45,120 --> 00:12:47,440 Speaker 1: inside of a sphere, but something that has a sort 262 00:12:47,440 --> 00:12:51,360 Speaker 1: of saddle shape. And so you draw triangle, you make 263 00:12:51,400 --> 00:12:53,440 Speaker 1: a measurement, and that tells you. And so we've done that. 264 00:12:53,559 --> 00:12:56,160 Speaker 1: We've made those triangles and we've measured them to very 265 00:12:56,200 --> 00:12:58,440 Speaker 1: high precision in three dimensional space. 266 00:12:58,559 --> 00:13:02,880 Speaker 2: Like this is on this in the sheet of the universe. 267 00:13:03,640 --> 00:13:07,280 Speaker 1: Yes, exactly. We've done it in two different ways, at 268 00:13:07,360 --> 00:13:08,920 Speaker 1: least that I can think of off the top of 269 00:13:08,960 --> 00:13:12,280 Speaker 1: my head. One is that we looked at giant cosmic 270 00:13:12,320 --> 00:13:15,000 Speaker 1: triangles in space. You know, we've looked at the cosmic 271 00:13:15,080 --> 00:13:18,840 Speaker 1: microwave background radiation this leftover photons from the birth of 272 00:13:18,840 --> 00:13:21,880 Speaker 1: the universe, and drawn these triangles and measured the angles 273 00:13:21,920 --> 00:13:24,560 Speaker 1: and and they come out to one hundred and eighty degrees. 274 00:13:24,720 --> 00:13:30,640 Speaker 1: It seems like space is flat. Space is flat flat, Yeah, 275 00:13:30,679 --> 00:13:33,560 Speaker 1: And that's a puzzle. It's really interesting that a lot 276 00:13:33,559 --> 00:13:35,920 Speaker 1: of people wonder, like, why is space flat? We've measured 277 00:13:35,960 --> 00:13:38,960 Speaker 1: to be flat to within you know, zero point one percent, 278 00:13:39,480 --> 00:13:41,640 Speaker 1: and for a long time that was a mystery. But 279 00:13:41,679 --> 00:13:42,319 Speaker 1: some people do. 280 00:13:42,480 --> 00:13:47,200 Speaker 2: Think that space could be curved, like what would why 281 00:13:47,200 --> 00:13:48,480 Speaker 2: would Why would that be weird? 282 00:13:49,200 --> 00:13:52,200 Speaker 1: Yeah, and well that's that leads perfectly into the second 283 00:13:52,240 --> 00:13:54,560 Speaker 1: way we've measured the curvature of space, which is you 284 00:13:54,600 --> 00:13:57,520 Speaker 1: might ask what causes space to curve? Right, why would 285 00:13:57,520 --> 00:14:00,560 Speaker 1: you expect space to be curved or flat or negative curved? 286 00:14:01,120 --> 00:14:03,240 Speaker 1: And the answer is that the thing that curves space 287 00:14:03,520 --> 00:14:07,440 Speaker 1: is matter. Right, You put stuff, matter and energy into 288 00:14:07,480 --> 00:14:10,320 Speaker 1: space and it curves it. That's what general relativity tells 289 00:14:10,400 --> 00:14:14,080 Speaker 1: us that that gravity is in fact the curvature of space. 290 00:14:14,480 --> 00:14:16,720 Speaker 1: So we know that space gets curved. Like you put 291 00:14:16,760 --> 00:14:18,520 Speaker 1: the Sun in the center of the Solar System, it 292 00:14:18,600 --> 00:14:22,160 Speaker 1: curves space so that the Earth very naturally moves in 293 00:14:22,200 --> 00:14:24,480 Speaker 1: a circle around it. Right, that's an impact of the 294 00:14:24,520 --> 00:14:28,040 Speaker 1: curvature of space. Nobody's turning the Earth. Nobody's like driving 295 00:14:28,080 --> 00:14:31,600 Speaker 1: the Earth around the Sun, right, but constantly turning. It's 296 00:14:31,640 --> 00:14:33,920 Speaker 1: moving in what it considers to be a straight line, 297 00:14:34,400 --> 00:14:37,600 Speaker 1: but the space is curved, so it's just moving constantly 298 00:14:37,640 --> 00:14:38,160 Speaker 1: in an orbit. 299 00:14:39,120 --> 00:14:41,920 Speaker 2: Gravity is not like a force pulling the Earth towards 300 00:14:41,920 --> 00:14:45,080 Speaker 2: the Sun. But gravity is more like its distorting the 301 00:14:45,080 --> 00:14:47,440 Speaker 2: space around the Sun, so that the Earth just kind 302 00:14:47,440 --> 00:14:49,600 Speaker 2: of naturally goes around it. 303 00:14:50,360 --> 00:14:52,440 Speaker 1: That's right. That's a great way to think about it. 304 00:14:52,840 --> 00:14:57,720 Speaker 1: And so matter distorts space and causes curvature of space, 305 00:14:58,000 --> 00:15:00,560 Speaker 1: and so you can ask is there enough matter and 306 00:15:00,680 --> 00:15:03,960 Speaker 1: energy in the universe to curve space or to make 307 00:15:04,000 --> 00:15:08,080 Speaker 1: it negatively curved or positively curved? Right? And if space 308 00:15:08,160 --> 00:15:10,600 Speaker 1: is totally empty, if there's no matter in it at all, 309 00:15:10,800 --> 00:15:13,640 Speaker 1: then it's negatively curved. You have to add energy and 310 00:15:13,720 --> 00:15:17,800 Speaker 1: matter to make space zero have zero curvature. And so 311 00:15:18,400 --> 00:15:20,680 Speaker 1: we've measured this. We've measured the total energy. 312 00:15:20,800 --> 00:15:23,400 Speaker 2: It naturally wants to be negatively curved, but if you 313 00:15:23,400 --> 00:15:25,640 Speaker 2: add stuff to it, then it gets straight. 314 00:15:26,520 --> 00:15:30,120 Speaker 1: That's right. Space with no energy density in it at 315 00:15:30,120 --> 00:15:33,480 Speaker 1: all would have negative curvature, and so you add stuff 316 00:15:33,520 --> 00:15:35,080 Speaker 1: to it. In fact, if you add I think it's 317 00:15:35,600 --> 00:15:39,960 Speaker 1: six hydrogen atoms worth of energy per square meter, then 318 00:15:40,040 --> 00:15:44,760 Speaker 1: space has zero curvature. It's between five and six. And 319 00:15:44,960 --> 00:15:47,160 Speaker 1: so we've measured the amount of stuff that's in the 320 00:15:47,240 --> 00:15:50,160 Speaker 1: universe and it all adds up to be just about 321 00:15:50,200 --> 00:15:53,960 Speaker 1: the right number to make space be not curved, which 322 00:15:54,000 --> 00:15:56,720 Speaker 1: is seems like a weird coincidence, right, It seems like 323 00:15:56,720 --> 00:15:59,760 Speaker 1: an important clue, like, why does all the stuff in 324 00:15:59,760 --> 00:16:02,200 Speaker 1: the unverse happen to add up to the number that's 325 00:16:02,480 --> 00:16:04,960 Speaker 1: just right to make space not be curved? 326 00:16:05,360 --> 00:16:07,920 Speaker 2: Would that Let's take a break. We'll be back in 327 00:16:08,120 --> 00:16:17,080 Speaker 2: just a short minute. 328 00:16:19,880 --> 00:16:22,480 Speaker 1: Space seems to be flat, at least space in our 329 00:16:22,560 --> 00:16:24,680 Speaker 1: part of the universe seems to be flat. It could 330 00:16:24,720 --> 00:16:26,520 Speaker 1: be that in other parts of the universe it's curved, right, 331 00:16:26,560 --> 00:16:29,360 Speaker 1: but in our part of the universe seems to be flat. 332 00:16:29,520 --> 00:16:32,160 Speaker 2: And we think that sort of a that it maybe 333 00:16:32,200 --> 00:16:35,040 Speaker 2: extends out to as far as we can see. 334 00:16:35,400 --> 00:16:37,600 Speaker 1: Yeah, it seems to follow the same rules. Okay, and 335 00:16:37,680 --> 00:16:39,920 Speaker 1: so you're absolutely right. That rules out, you know, the 336 00:16:40,080 --> 00:16:42,280 Speaker 1: potato universe that we're living on the surface of its 337 00:16:42,400 --> 00:16:45,920 Speaker 1: huge cosmic potato or bubble universe whatever. It rules out 338 00:16:45,960 --> 00:16:49,600 Speaker 1: the saddle universe or the universe's negative curvature. Seems like 339 00:16:49,680 --> 00:16:50,760 Speaker 1: space is flat, which is. 340 00:16:50,880 --> 00:16:55,960 Speaker 2: Flat going one direction forever, I'll just keep going. 341 00:16:56,280 --> 00:16:58,840 Speaker 1: Not necessarily right, we know space is flat. That doesn't 342 00:16:58,880 --> 00:17:02,480 Speaker 1: necessarily mean that it's infinite. It's a natural idea, right. 343 00:17:02,840 --> 00:17:05,400 Speaker 1: If space is flat, then it doesn't curve on itself, 344 00:17:05,400 --> 00:17:07,000 Speaker 1: And so it seems like you could be able to 345 00:17:07,000 --> 00:17:07,880 Speaker 1: go on forever. 346 00:17:07,760 --> 00:17:10,080 Speaker 2: But earlier that you can't just have a wall. 347 00:17:11,040 --> 00:17:13,639 Speaker 1: You can't just have a wall. But but since we 348 00:17:13,680 --> 00:17:15,800 Speaker 1: don't know what space is, we don't really know how 349 00:17:15,800 --> 00:17:18,400 Speaker 1: it works, we don't really know how it's connected. It's 350 00:17:18,480 --> 00:17:21,919 Speaker 1: still possible that it could be flat but connected in 351 00:17:21,960 --> 00:17:24,840 Speaker 1: a weird way, so where one edge is connected to 352 00:17:24,880 --> 00:17:27,880 Speaker 1: the other edge, like you go flat you're moving through 353 00:17:27,920 --> 00:17:31,200 Speaker 1: flat space, but it just loops on back on itself, 354 00:17:31,480 --> 00:17:35,640 Speaker 1: like it's connected in that way, like an asteroids game. 355 00:17:35,720 --> 00:17:37,600 Speaker 1: You know, you go at the edge of the screen, 356 00:17:37,320 --> 00:17:38,320 Speaker 1: but you appear on the. 357 00:17:38,280 --> 00:17:41,520 Speaker 2: Other side, like you teleport to the other side. 358 00:17:42,240 --> 00:17:45,439 Speaker 1: Yeah, yeah, and not necessarily teleport, Like that could just 359 00:17:45,480 --> 00:17:46,960 Speaker 1: be the way space is connected. 360 00:17:47,160 --> 00:17:50,520 Speaker 2: So that's weird. That's that wouldn't feel you mean, like 361 00:17:50,560 --> 00:17:53,600 Speaker 2: an asteroid games or like pac Man where you walk 362 00:17:53,640 --> 00:17:55,359 Speaker 2: off one side of the screen and suddenly you appear 363 00:17:55,359 --> 00:17:59,080 Speaker 2: on the other side, Like that is it possibility? Physicists 364 00:17:59,160 --> 00:18:00,960 Speaker 2: are like, hey, that could be true. 365 00:18:01,640 --> 00:18:04,880 Speaker 1: That certainly could be true. Yes, absolutely, But the other 366 00:18:04,920 --> 00:18:07,840 Speaker 1: possibility is also true, which is maybe it just goes 367 00:18:07,880 --> 00:18:10,680 Speaker 1: on forever. Right, It could be that the that space 368 00:18:10,720 --> 00:18:14,760 Speaker 1: goes on forever, And that's also kind of weird because 369 00:18:14,920 --> 00:18:16,399 Speaker 1: that's infinite. 370 00:18:15,920 --> 00:18:17,480 Speaker 2: Space in space. 371 00:18:18,160 --> 00:18:21,119 Speaker 1: Yeah, yeah, and it could be that space is flat, 372 00:18:21,160 --> 00:18:24,000 Speaker 1: but it just ends because we can't see past the 373 00:18:24,040 --> 00:18:28,560 Speaker 1: observable universe, and so we have intuition and ideas and 374 00:18:28,600 --> 00:18:31,119 Speaker 1: speculation and we think, oh, this would be more natural, 375 00:18:31,200 --> 00:18:33,199 Speaker 1: or that would be more natural, or I wish the 376 00:18:33,280 --> 00:18:35,880 Speaker 1: universe looked that way, but at this point that's all 377 00:18:35,920 --> 00:18:44,480 Speaker 1: we can do. Yeah. So it's a fascinating concept, infinity because, 378 00:18:44,920 --> 00:18:48,040 Speaker 1: as you say, if things go on forever and then 379 00:18:48,080 --> 00:18:51,520 Speaker 1: you get infinite number of tries at everything, then that 380 00:18:51,600 --> 00:18:55,320 Speaker 1: means that, given quantum randomness, you really do get every 381 00:18:55,359 --> 00:18:57,919 Speaker 1: possibility out there. So that means it's somewhere out there, 382 00:18:57,920 --> 00:19:01,480 Speaker 1: there's a universe where we're recording podcast and I'm named 383 00:19:01,520 --> 00:19:04,240 Speaker 1: Jorge and you're name Daniel, and right, you know, another 384 00:19:04,320 --> 00:19:07,800 Speaker 1: universe where every possible thing you can imagine happens. That's 385 00:19:07,920 --> 00:19:10,920 Speaker 1: really true, I mean, it's actually happening. If there is 386 00:19:10,960 --> 00:19:13,520 Speaker 1: an infinite universe with infinite space, it means it could 387 00:19:13,560 --> 00:19:15,240 Speaker 1: be really far away and we could never get there 388 00:19:15,280 --> 00:19:18,400 Speaker 1: and improve it. But if that is reality, then it's 389 00:19:18,480 --> 00:19:21,840 Speaker 1: really happening right now, which is crazy to think about. 390 00:19:21,600 --> 00:19:24,160 Speaker 2: It, right, right, we just will never see it. 391 00:19:24,640 --> 00:19:27,560 Speaker 1: We'll never see it, yeah, or if we wait long enough, 392 00:19:27,560 --> 00:19:30,680 Speaker 1: maybe we would. But it's also so it's on one hand, 393 00:19:30,720 --> 00:19:33,720 Speaker 1: like really crazy to imagine infinite universe with infinite stuff 394 00:19:33,720 --> 00:19:36,040 Speaker 1: in it. On the other hand, it's sort of natural, right, 395 00:19:36,160 --> 00:19:39,920 Speaker 1: Like what's the simplest explanation is it's simpler to imagine 396 00:19:39,920 --> 00:19:43,520 Speaker 1: an edge, right, like a limited amount of stuff. I 397 00:19:43,640 --> 00:19:46,000 Speaker 1: find those ideas to be sort of weird, and they 398 00:19:46,000 --> 00:19:50,960 Speaker 1: sort of call back to, you know, geocentrism, the idea 399 00:19:51,000 --> 00:19:53,640 Speaker 1: that we're the center, we're an important place in the universe. 400 00:19:54,280 --> 00:19:56,159 Speaker 1: It's much more natural for me to think the universe 401 00:19:56,240 --> 00:19:58,280 Speaker 1: just goes on forever and we're just at one dot 402 00:19:58,320 --> 00:20:02,359 Speaker 1: in a random spot in it. Otherwise they have to explain, 403 00:20:02,400 --> 00:20:06,040 Speaker 1: like why the universe began here, Like imagine the scenario 404 00:20:06,160 --> 00:20:09,720 Speaker 1: the infinite space but finite stuff scenario. Then you have 405 00:20:09,760 --> 00:20:12,000 Speaker 1: to ask, why did the Big Bang happen here and 406 00:20:12,119 --> 00:20:14,840 Speaker 1: not fifty billion light years to the left or to 407 00:20:14,880 --> 00:20:15,440 Speaker 1: the right. 408 00:20:15,359 --> 00:20:19,000 Speaker 2: In that infinite space? Why is that clump matter here 409 00:20:19,040 --> 00:20:19,560 Speaker 2: where we are? 410 00:20:20,200 --> 00:20:24,200 Speaker 1: Yeah, So my personal preference, based on no science at all, 411 00:20:24,600 --> 00:20:27,720 Speaker 1: is the infinite space, infinite stuff universe because It sort 412 00:20:27,720 --> 00:20:31,720 Speaker 1: of puts to rest some of those questions who raises others? 413 00:20:31,960 --> 00:20:35,960 Speaker 2: Right? It doesn't raise weird questions or inconsistencies. 414 00:20:36,680 --> 00:20:37,000 Speaker 3: Yeah. 415 00:20:37,080 --> 00:20:39,960 Speaker 1: Yeah, it just asks you to imagine creation of an 416 00:20:39,960 --> 00:20:42,520 Speaker 1: infinite stuff in a moment. I mean that's not too 417 00:20:42,600 --> 00:20:46,719 Speaker 1: much that Yeah. Currently, I don't know of anybody who 418 00:20:46,840 --> 00:20:50,080 Speaker 1: has such clever ideas for ways to determine whether the 419 00:20:50,160 --> 00:20:53,040 Speaker 1: universe is infinite or finite by just looking at stuff 420 00:20:53,080 --> 00:20:55,320 Speaker 1: around us. So the only way we could do it 421 00:20:55,359 --> 00:20:57,960 Speaker 1: is direct by looking at the universe, which of course 422 00:20:58,000 --> 00:21:01,159 Speaker 1: we can't. So currently it feels impossible, but you know, 423 00:21:01,200 --> 00:21:02,600 Speaker 1: we always have to leave a little bit of an 424 00:21:02,640 --> 00:21:06,080 Speaker 1: open door there for some future physicists more clever than 425 00:21:06,160 --> 00:21:09,040 Speaker 1: us comes up with a clever way to probe whether 426 00:21:09,080 --> 00:21:11,520 Speaker 1: the universe is finite or infinite just by looking at 427 00:21:11,560 --> 00:21:12,360 Speaker 1: clues around us. 428 00:21:12,680 --> 00:21:16,320 Speaker 2: You might say that there's plenty of room to grow. 429 00:21:19,119 --> 00:21:21,720 Speaker 1: There. Certainly is there? Certainly is cool. 430 00:21:21,960 --> 00:21:26,159 Speaker 2: Well, I hope you guys enjoyed that discussion. Yeah, and 431 00:21:26,200 --> 00:21:29,360 Speaker 2: maybe when you look out at night into the stars, 432 00:21:29,359 --> 00:21:32,359 Speaker 2: do you think about the idea that maybe the universe 433 00:21:32,440 --> 00:21:36,760 Speaker 2: is infinite or maybe we're seeing all that there is? 434 00:21:37,080 --> 00:21:40,320 Speaker 1: And regardless It's a beautiful, gorgeous universe out there, and 435 00:21:40,400 --> 00:21:43,600 Speaker 1: if you're into views, the best view out there is 436 00:21:43,760 --> 00:21:45,680 Speaker 1: the night sky in the top of a mountain where 437 00:21:45,680 --> 00:21:49,080 Speaker 1: you can see billions of light years across amazing vistas. So, 438 00:21:49,920 --> 00:21:52,199 Speaker 1: however big the universe is, go out and enjoy it. 439 00:21:57,920 --> 00:21:59,800 Speaker 1: Do you have a question you wish we would cover, 440 00:22:00,160 --> 00:22:02,359 Speaker 1: Send it to us. We'd love to hear from you. 441 00:22:02,359 --> 00:22:05,520 Speaker 1: You can find us on Facebook, Twitter, and Instagram at 442 00:22:05,720 --> 00:22:09,679 Speaker 1: Daniel and Jorge One Word, or email us to feedback 443 00:22:09,720 --> 00:22:24,600 Speaker 1: at Danielandhorge dot com.