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