1 00:00:08,640 --> 00:00:11,799 Speaker 1: Daniel, what happens if you have a great new physics theory? 2 00:00:12,960 --> 00:00:17,520 Speaker 1: I mean just really beautiful, gorgeous, perfect explains almost everything. 3 00:00:17,720 --> 00:00:21,040 Speaker 1: This sounds great so far, but I knew it was 4 00:00:21,079 --> 00:00:24,200 Speaker 1: a butt coming. But it's wrong about one thing. Well, 5 00:00:24,320 --> 00:00:26,200 Speaker 1: is it like a little thing? Yeah, just a little 6 00:00:26,200 --> 00:00:29,680 Speaker 1: thing called the whole universe? All right? Well, is it 7 00:00:29,800 --> 00:00:32,320 Speaker 1: like just a little bit wrong? It's wrong by about 8 00:00:32,360 --> 00:00:35,560 Speaker 1: the size of the whole universe. Doesn't sound like such 9 00:00:35,600 --> 00:00:38,280 Speaker 1: a great theory. But you know there's always a fix. 10 00:00:38,400 --> 00:00:40,360 Speaker 1: Oh yeah, what's that? Well, engineers would love it. We 11 00:00:40,440 --> 00:00:43,960 Speaker 1: just add a fudge factor. And here's how safety factors 12 00:00:43,960 --> 00:00:46,960 Speaker 1: not fudge factors. But that's it. Really. Just put a 13 00:00:46,960 --> 00:00:49,120 Speaker 1: big number in it and you can fix it. Step one, 14 00:00:49,159 --> 00:00:51,199 Speaker 1: put in a big number. Step two, give it a 15 00:00:51,240 --> 00:01:11,360 Speaker 1: fancy sounding name. Hi. I'm Orge I'm a cartoonists and 16 00:01:11,400 --> 00:01:14,880 Speaker 1: the creator of PhD comics. Hi. I'm Daniel Whiteson. I'm 17 00:01:14,920 --> 00:01:18,120 Speaker 1: a particle physicist, and I have never fixed a theory 18 00:01:18,160 --> 00:01:20,920 Speaker 1: with a fudge factor, and not yet, Daniel, how about 19 00:01:20,920 --> 00:01:23,920 Speaker 1: a podcast? Have you faced the podcast? I've never fudged 20 00:01:23,920 --> 00:01:27,000 Speaker 1: the physics on this podcast, but I've also never come 21 00:01:27,080 --> 00:01:29,160 Speaker 1: up with my own theory of the universe. Have you 22 00:01:29,200 --> 00:01:32,400 Speaker 1: had fudge while you were recording this podcast? My theory 23 00:01:32,560 --> 00:01:34,720 Speaker 1: is that fudge is the basic element of the universe 24 00:01:34,760 --> 00:01:37,240 Speaker 1: because it brings joy, and in the end, what's life 25 00:01:37,240 --> 00:01:40,280 Speaker 1: about other than beauty and joy and in chocolate obviously, 26 00:01:41,520 --> 00:01:44,840 Speaker 1: But welcome to our podcast Daniel and jrge Explained the Universe, 27 00:01:44,880 --> 00:01:47,600 Speaker 1: a production of I Heart Radio, in which we compare 28 00:01:47,680 --> 00:01:51,680 Speaker 1: the universe to various snack foods, delicious and dark and 29 00:01:51,840 --> 00:01:54,960 Speaker 1: dense sometimes but with all the stuff that's happening out 30 00:01:55,000 --> 00:01:56,920 Speaker 1: there in this crazy world. We want to take you 31 00:01:56,960 --> 00:02:00,280 Speaker 1: on a tour of the grandest, deepest, most amazing but 32 00:02:00,520 --> 00:02:04,120 Speaker 1: yet strangely accessible questions of the universe. Right, we want 33 00:02:04,160 --> 00:02:05,960 Speaker 1: to take your mind and have it go on a 34 00:02:05,960 --> 00:02:08,880 Speaker 1: trip out into the far reaches of the cosmos and 35 00:02:09,000 --> 00:02:12,320 Speaker 1: to think about what it is that we're all doing here, 36 00:02:12,320 --> 00:02:14,760 Speaker 1: and how did this crazy universe come to be and 37 00:02:14,800 --> 00:02:16,400 Speaker 1: why is it the way it is. That's right, because 38 00:02:16,400 --> 00:02:19,240 Speaker 1: the universe belongs to all of us, and wondering and 39 00:02:19,280 --> 00:02:22,200 Speaker 1: being curious about the universe is as old as being human. 40 00:02:22,280 --> 00:02:25,200 Speaker 1: And we think that everybody should understand what scientists are 41 00:02:25,280 --> 00:02:28,720 Speaker 1: thinking about, what the deepest questions are and what scientists 42 00:02:28,760 --> 00:02:31,720 Speaker 1: are pretty clueless about and only pretend to think they 43 00:02:31,800 --> 00:02:37,160 Speaker 1: understand anything about. Physicists fudge things. Sometimes that's right, and 44 00:02:37,240 --> 00:02:40,679 Speaker 1: not little questions, and not by a little bit. Sometimes 45 00:02:40,760 --> 00:02:44,120 Speaker 1: we need a really really massive fudge, really big bowl 46 00:02:44,160 --> 00:02:46,600 Speaker 1: of fudge. Hey, you know on a bad day that 47 00:02:46,720 --> 00:02:48,919 Speaker 1: sometimes that's all that makes you feel like, that's pretty 48 00:02:48,919 --> 00:02:51,600 Speaker 1: good about it? Right now? Yeah, I wouldn't mind swimming 49 00:02:51,600 --> 00:02:53,560 Speaker 1: in a swimming pool full of fudge. All right, we'll 50 00:02:53,560 --> 00:02:56,600 Speaker 1: wipe that mental image, folks and replace it with questions 51 00:02:56,600 --> 00:02:58,680 Speaker 1: about the universe, so to be on the program. We'll 52 00:02:58,720 --> 00:03:02,919 Speaker 1: be talking about what such fudge fact about the universe 53 00:03:02,960 --> 00:03:05,120 Speaker 1: that physicists have come up with. And this comes up 54 00:03:05,120 --> 00:03:08,600 Speaker 1: a lot in discussions about the entire universe and the 55 00:03:08,600 --> 00:03:12,800 Speaker 1: theories that underlied, like general relativity and dark energy. That's right, 56 00:03:12,840 --> 00:03:15,240 Speaker 1: and this is one of my favorite topics in physics 57 00:03:15,280 --> 00:03:18,280 Speaker 1: because it's a topic where we are absolutely sure that 58 00:03:18,360 --> 00:03:21,120 Speaker 1: we are in the beginning days of understanding. Like if 59 00:03:21,120 --> 00:03:23,720 Speaker 1: you go back and read in history about people thinking 60 00:03:23,800 --> 00:03:26,240 Speaker 1: about the nature of reality and our things made out 61 00:03:26,280 --> 00:03:28,800 Speaker 1: of atoms or made out of fire and water, it 62 00:03:28,800 --> 00:03:32,240 Speaker 1: feels like man, they had some pretty crazy ideas back then. 63 00:03:32,280 --> 00:03:34,359 Speaker 1: They had no idea what they were doing, right, While 64 00:03:34,360 --> 00:03:37,120 Speaker 1: there are fields of physics where we are also just 65 00:03:37,320 --> 00:03:41,280 Speaker 1: starting out having all sorts of crazy ideas, which physicists 66 00:03:41,280 --> 00:03:43,560 Speaker 1: in ten fifty or a hundred years will look back 67 00:03:43,640 --> 00:03:47,240 Speaker 1: and snortal act. Yeah, and this one's particularly interesting because 68 00:03:47,360 --> 00:03:49,119 Speaker 1: it all sort of comes down to a number. Would 69 00:03:49,160 --> 00:03:52,080 Speaker 1: you say it's the biggest number in physics. It's definitely 70 00:03:52,120 --> 00:03:57,240 Speaker 1: the wrongest number in physics, the wrongest and the biggest. Man. 71 00:03:57,440 --> 00:03:58,960 Speaker 1: One of the weird things about this number is why 72 00:03:59,000 --> 00:04:01,520 Speaker 1: it's so small. We think it should be a lot bigger, 73 00:04:01,520 --> 00:04:03,240 Speaker 1: and it turns out to be kind of small, and 74 00:04:03,600 --> 00:04:07,000 Speaker 1: we don't understand that. I see it's a small number numerically, 75 00:04:07,160 --> 00:04:09,840 Speaker 1: but I'm saying, like, in terms of significance, it's a 76 00:04:09,920 --> 00:04:12,760 Speaker 1: huge number. It's a little number with big significant the 77 00:04:12,800 --> 00:04:15,640 Speaker 1: biggest slice of the fudge pie of the universe. To 78 00:04:15,680 --> 00:04:23,279 Speaker 1: be on the program, we'll be talking about what is 79 00:04:23,480 --> 00:04:27,760 Speaker 1: the cosmological constant? All right? So this was a question 80 00:04:27,800 --> 00:04:30,120 Speaker 1: that was sent to us by someone from Belgium. So 81 00:04:30,160 --> 00:04:34,600 Speaker 1: this is Pascal asking what is the cosmological constant? Hi, 82 00:04:34,720 --> 00:04:38,120 Speaker 1: Danielle and Hockett. I have a nagging question about the 83 00:04:38,160 --> 00:04:43,640 Speaker 1: cosmological constant. I understand that Anstein introduced the cosmological constant 84 00:04:43,680 --> 00:04:46,480 Speaker 1: in the field equation because he thought that this would 85 00:04:46,520 --> 00:04:49,719 Speaker 1: make the universe static, but in fact, the presence of 86 00:04:49,760 --> 00:04:53,279 Speaker 1: the cosmological constant in the field equation actually shows that 87 00:04:53,320 --> 00:04:56,440 Speaker 1: the universe is expanding. So that's why he said that 88 00:04:56,680 --> 00:04:59,360 Speaker 1: this was the biggest mixtake of his life, which, by 89 00:04:59,360 --> 00:05:01,479 Speaker 1: the way, shows one more time how brilliant it was. 90 00:05:01,560 --> 00:05:03,560 Speaker 1: Even when he was making you mistake, it turns out 91 00:05:03,560 --> 00:05:06,480 Speaker 1: that it was right. So my question is, how does 92 00:05:06,520 --> 00:05:10,080 Speaker 1: the presence of the cosmological constant in the fit equations 93 00:05:10,120 --> 00:05:14,680 Speaker 1: show that the universe is expanding? And more deeply, where 94 00:05:14,720 --> 00:05:18,720 Speaker 1: did this cosmological constant come from? Who quoten quote invented it? 95 00:05:19,200 --> 00:05:22,520 Speaker 1: Thank you so much for your podcasts and cheers from Belgium. 96 00:05:22,520 --> 00:05:25,440 Speaker 1: All right, cheers, Pascal. Thanks for sending in that question, 97 00:05:25,640 --> 00:05:27,520 Speaker 1: and I think it's awesome that it's a question that's 98 00:05:27,560 --> 00:05:30,560 Speaker 1: nagging up, a question that next you also, Daniel doesn't 99 00:05:30,600 --> 00:05:33,120 Speaker 1: keep you open, Oh my gosh, the history and future 100 00:05:33,160 --> 00:05:35,840 Speaker 1: fate of the universe totally keeps me up at night. 101 00:05:35,960 --> 00:05:38,720 Speaker 1: I mean, that's like the biggest question in physics. You know, 102 00:05:39,000 --> 00:05:42,440 Speaker 1: literally literally the biggest question in physics. Are we living 103 00:05:42,640 --> 00:05:44,719 Speaker 1: in the space that's going to be crunched? Are we 104 00:05:44,839 --> 00:05:47,640 Speaker 1: exploding out into the heat death of the universe? What 105 00:05:47,800 --> 00:05:50,440 Speaker 1: is the shape, the size and nature the dynamics of 106 00:05:50,480 --> 00:05:53,479 Speaker 1: the universe, like thought of as a whole object. It's 107 00:05:53,520 --> 00:05:57,000 Speaker 1: it's incredible that humans can even consider things so vast 108 00:05:57,040 --> 00:05:59,200 Speaker 1: in our tiny little minds and sort of comes down 109 00:05:59,200 --> 00:06:02,000 Speaker 1: to one number almost, it seems to come down to 110 00:06:02,000 --> 00:06:03,840 Speaker 1: one number, a number we had to insert into the 111 00:06:03,880 --> 00:06:07,039 Speaker 1: equations to explain what we see. And you know, the 112 00:06:07,080 --> 00:06:10,320 Speaker 1: reason I love this topic is because not only do 113 00:06:10,400 --> 00:06:13,240 Speaker 1: we have fresh new ideas for how to explain what 114 00:06:13,279 --> 00:06:15,520 Speaker 1: we see, but our understanding of what we're seeing has 115 00:06:15,560 --> 00:06:18,800 Speaker 1: also changed. You know, a hundred years ago, we thought 116 00:06:18,960 --> 00:06:21,400 Speaker 1: there was just one galaxy in the universe, and then 117 00:06:21,440 --> 00:06:24,200 Speaker 1: we discovered their other galaxies and they're zooming away from us. 118 00:06:24,240 --> 00:06:26,280 Speaker 1: And then we discovered, oh my gosh, the things are 119 00:06:26,320 --> 00:06:29,440 Speaker 1: expanding even faster and faster. So like, only twenty years 120 00:06:29,440 --> 00:06:31,800 Speaker 1: ago did we figure out that there was this weird 121 00:06:31,880 --> 00:06:35,080 Speaker 1: thing called dark energy tearing our universe apart. And now 122 00:06:35,120 --> 00:06:37,920 Speaker 1: we're struggling to explain it. So, yeah, it's a big knack. 123 00:06:38,279 --> 00:06:42,359 Speaker 1: It's dark energy, just fudge. Maybe something to think about. 124 00:06:42,920 --> 00:06:45,880 Speaker 1: Fudge energy would have been a energy energy, the quantum 125 00:06:45,880 --> 00:06:48,880 Speaker 1: fudge energy. The number is called the cosmological constant. And 126 00:06:48,880 --> 00:06:50,880 Speaker 1: so as usual, we were wondering how many people out 127 00:06:50,880 --> 00:06:53,839 Speaker 1: there and know what this term means and where it 128 00:06:53,880 --> 00:06:56,080 Speaker 1: came from. So as usual, Daniel went out and asked 129 00:06:56,080 --> 00:06:59,320 Speaker 1: people on the street what is the cosmological constant? And 130 00:06:59,600 --> 00:07:01,560 Speaker 1: before you listen to these answers, think about it for 131 00:07:01,560 --> 00:07:04,080 Speaker 1: a second. If someone asked you what it is, would 132 00:07:04,120 --> 00:07:06,360 Speaker 1: you know what to say. Here's what people had to say. 133 00:07:06,800 --> 00:07:10,040 Speaker 1: I have no idea what it is. The idea that 134 00:07:10,080 --> 00:07:12,320 Speaker 1: there's one constant that explains all the others, so we 135 00:07:12,360 --> 00:07:14,760 Speaker 1: don't have to have like forty two to explain all 136 00:07:14,760 --> 00:07:17,920 Speaker 1: the different little stuff. I think, So I have no clue. 137 00:07:17,960 --> 00:07:20,360 Speaker 1: Does that I mean it has something to do with light? 138 00:07:20,480 --> 00:07:24,720 Speaker 1: Maybe I don't know that's a cosmological constant, so I 139 00:07:24,720 --> 00:07:27,160 Speaker 1: would say it's something to do with the creation of 140 00:07:27,280 --> 00:07:30,400 Speaker 1: life or um. The long those line is probably like 141 00:07:31,320 --> 00:07:35,000 Speaker 1: a number like Dealer's constant or something. Some some mathematical 142 00:07:35,080 --> 00:07:40,080 Speaker 1: things it's some sort of scale factor. Uh. I guess 143 00:07:40,160 --> 00:07:43,040 Speaker 1: it's the best way to describe it. No, if you 144 00:07:43,120 --> 00:07:46,840 Speaker 1: had to guess like movement, something like that, something that's 145 00:07:46,840 --> 00:07:51,760 Speaker 1: more fixed and something that throughout time they've seen constantly. 146 00:07:51,800 --> 00:07:54,280 Speaker 1: There heard of it, but I can't remember right now. 147 00:07:55,520 --> 00:08:00,400 Speaker 1: I believe that refers to Einstein's whoopsie and which had 148 00:08:00,440 --> 00:08:02,960 Speaker 1: to add a factor to an equation to account for 149 00:08:03,640 --> 00:08:08,480 Speaker 1: either the repulsion or attraction that would actually make the 150 00:08:08,560 --> 00:08:12,320 Speaker 1: evolution of the universe's topology. I guess you must say 151 00:08:12,520 --> 00:08:14,960 Speaker 1: um stable or not stable. I know I'm getting that 152 00:08:15,000 --> 00:08:18,080 Speaker 1: little right. It's also synonymous these days with dark matter, 153 00:08:18,280 --> 00:08:21,040 Speaker 1: I think, or the effect of dark matter. You guess, 154 00:08:21,080 --> 00:08:27,320 Speaker 1: something to do with how the universe expense. Okay, something 155 00:08:27,320 --> 00:08:30,800 Speaker 1: about the shape of the cosmos. I'm not sure, all right, 156 00:08:31,040 --> 00:08:33,480 Speaker 1: some pretty good answers out there. Yeah, some people are 157 00:08:33,480 --> 00:08:36,760 Speaker 1: pretty close, and then some other people sort of grasping at, 158 00:08:36,840 --> 00:08:43,240 Speaker 1: you know, broad things, because it's it sounds broad and consequential, right, cosmologicalsmologically, Yeah, 159 00:08:43,280 --> 00:08:45,679 Speaker 1: it's not like it's not like the local neighborhood constant 160 00:08:45,880 --> 00:08:52,160 Speaker 1: or sofa my sofa constant. You know, it's like it's 161 00:08:52,200 --> 00:08:55,320 Speaker 1: it's going for the it's going for the fences, cosmological cost, 162 00:08:55,559 --> 00:08:57,240 Speaker 1: it's a dramatic name. What do you think about the name? 163 00:08:57,280 --> 00:08:59,480 Speaker 1: You approve, Well, let me see what it is. You 164 00:08:59,520 --> 00:09:03,680 Speaker 1: know it is? It is it cosmological and insignificance. I 165 00:09:03,720 --> 00:09:06,120 Speaker 1: think you'll find that it is. My guess is that 166 00:09:06,160 --> 00:09:09,280 Speaker 1: it's not even a constant there, Like you guys got 167 00:09:09,320 --> 00:09:12,880 Speaker 1: even that part of the name wrong. That's a good guess. 168 00:09:13,240 --> 00:09:14,720 Speaker 1: And you know, it's a kind of thing where you 169 00:09:14,760 --> 00:09:16,520 Speaker 1: think it's a constant, You call it a constant, then 170 00:09:16,520 --> 00:09:19,400 Speaker 1: you discover hopes it's changing, and you still call it 171 00:09:19,480 --> 00:09:22,400 Speaker 1: a constant. The only thing that's constant is the name. 172 00:09:24,120 --> 00:09:26,600 Speaker 1: The only thing that isn't changing about it. But it 173 00:09:26,679 --> 00:09:29,880 Speaker 1: is sort of a pretty big topic, and it all 174 00:09:29,920 --> 00:09:33,800 Speaker 1: sort of originated with Einstein, right, This is something Einstein 175 00:09:33,960 --> 00:09:36,360 Speaker 1: came up with kind of by accident. So tell us 176 00:09:36,360 --> 00:09:37,960 Speaker 1: about the history. And this is something you have to 177 00:09:38,040 --> 00:09:40,719 Speaker 1: understand the history of it. And Pascal's question really goes 178 00:09:40,760 --> 00:09:43,839 Speaker 1: to that you have to understand sort of where Einstein's 179 00:09:43,880 --> 00:09:46,600 Speaker 1: mind was when he was trying to explain the universe. 180 00:09:46,760 --> 00:09:49,480 Speaker 1: And you're right, it began with Einstein, but really it 181 00:09:49,520 --> 00:09:52,640 Speaker 1: was Einstein building on what Newton did. This was like 182 00:09:52,800 --> 00:09:55,000 Speaker 1: in nineteen fifteen around right, Yeah, this is the early 183 00:09:55,080 --> 00:09:58,520 Speaker 1: nineteen hundreds, and Einstein was trying to understand the universe 184 00:09:58,920 --> 00:10:02,760 Speaker 1: and its shape and how and how gravity works because 185 00:10:02,800 --> 00:10:05,040 Speaker 1: he had gotten these ideas from Newton that everybody else 186 00:10:05,120 --> 00:10:08,680 Speaker 1: had that gravity is something where two objects with mass 187 00:10:08,720 --> 00:10:11,160 Speaker 1: pull on each other. And he didn't like this idea, 188 00:10:11,640 --> 00:10:14,040 Speaker 1: and he tried to come up with a more general 189 00:10:14,080 --> 00:10:18,480 Speaker 1: idea for what gravity might be, and he reimagined gravity completely, right. 190 00:10:18,559 --> 00:10:21,680 Speaker 1: His idea of gravity was not that gravity is like 191 00:10:21,679 --> 00:10:24,200 Speaker 1: a force or two objects pull on each other, but 192 00:10:24,280 --> 00:10:27,880 Speaker 1: that it's sort of the effect of mass on space itself. 193 00:10:28,400 --> 00:10:31,520 Speaker 1: So space is no longer just like a backdrop. It's 194 00:10:31,520 --> 00:10:34,480 Speaker 1: not like an emptiness on which things happen. It's a 195 00:10:34,559 --> 00:10:38,520 Speaker 1: dynamical part of the universe. Meaning you put mass into space, 196 00:10:38,600 --> 00:10:42,760 Speaker 1: space changes, right, And so he imagined gravity as a 197 00:10:42,800 --> 00:10:46,440 Speaker 1: bending of space. Any local density of energy will bend 198 00:10:46,559 --> 00:10:49,160 Speaker 1: space around it, changing the shape of the universe. And 199 00:10:49,240 --> 00:10:51,839 Speaker 1: this idea sort of came up from the equations, right, 200 00:10:51,880 --> 00:10:53,360 Speaker 1: Like if you sort of look at the equations of 201 00:10:53,400 --> 00:10:56,719 Speaker 1: gravity and things moving because of gravity, you can sort 202 00:10:56,720 --> 00:10:59,200 Speaker 1: of look at the equations into ways as a as 203 00:10:59,240 --> 00:11:01,440 Speaker 1: a force or as a as a kind of a 204 00:11:01,440 --> 00:11:03,760 Speaker 1: bending of space. Right. It's not like he suddenly came 205 00:11:03,800 --> 00:11:05,080 Speaker 1: up with this idea. Well. I think it had a 206 00:11:05,120 --> 00:11:08,199 Speaker 1: complex history and it required him to merge some ideas 207 00:11:08,320 --> 00:11:11,199 Speaker 1: or mathematics that had recently been developed. But I think 208 00:11:11,240 --> 00:11:14,840 Speaker 1: it's a pretty big conceptual shift to say gravity is 209 00:11:14,880 --> 00:11:18,680 Speaker 1: not just a force between two objects, like electromagnetism, but 210 00:11:18,720 --> 00:11:21,440 Speaker 1: it's something conceptually very different. It's a changing of the 211 00:11:21,440 --> 00:11:23,920 Speaker 1: shape of space itself. I think that's sort of mind bending, 212 00:11:24,000 --> 00:11:25,760 Speaker 1: the way you know, the mind bending to think about 213 00:11:25,800 --> 00:11:28,600 Speaker 1: space and bending. Right. And so he came up with 214 00:11:28,600 --> 00:11:31,040 Speaker 1: this idea and it worked really well for lots of 215 00:11:31,080 --> 00:11:33,840 Speaker 1: things that he was able to recover Newton's theory from it. 216 00:11:33,880 --> 00:11:36,680 Speaker 1: He showed that thinking about gravity in this way gave 217 00:11:36,720 --> 00:11:39,719 Speaker 1: the same predictions that Newton gave. Right. It didn't mean 218 00:11:39,720 --> 00:11:43,280 Speaker 1: apples should fall differently from trees, right, because Newton's theory 219 00:11:43,360 --> 00:11:45,440 Speaker 1: sort of worked, right, It's been tested a lot of 220 00:11:45,440 --> 00:11:48,840 Speaker 1: ways and even explained the motion of the planets mostly right. 221 00:11:49,040 --> 00:11:50,720 Speaker 1: And so it's important when you come up with like 222 00:11:50,840 --> 00:11:53,880 Speaker 1: a deeper theory that it still explains all the stuff 223 00:11:53,920 --> 00:11:56,679 Speaker 1: that Newton had gotten right. Right in einsience theory, the 224 00:11:56,760 --> 00:11:59,160 Speaker 1: apple doesn't fall from the tree. It just sort of 225 00:11:59,360 --> 00:12:02,160 Speaker 1: rides down own the space time, or it sits in 226 00:12:02,200 --> 00:12:06,760 Speaker 1: the same spacetime. Yeah, it's surfs, right, it's surfs on space. 227 00:12:06,880 --> 00:12:09,480 Speaker 1: But the motion is the same. Right, Einstein doesn't predict 228 00:12:09,520 --> 00:12:12,160 Speaker 1: that you'd see anything different from when an apple falls. 229 00:12:12,559 --> 00:12:15,200 Speaker 1: But then it did make small differences in predictions for 230 00:12:15,240 --> 00:12:18,880 Speaker 1: like how mercury moved. Really, yeah, that's the procession of mercury. 231 00:12:19,280 --> 00:12:21,520 Speaker 1: And so he proved that his idea was right and 232 00:12:21,520 --> 00:12:24,080 Speaker 1: the Newton's idea was wrong. But then he took the 233 00:12:24,080 --> 00:12:26,199 Speaker 1: idea even bigger. He said, all right, if we think 234 00:12:26,200 --> 00:12:29,199 Speaker 1: about this, what does that mean for the whole universe? Right? 235 00:12:29,480 --> 00:12:31,880 Speaker 1: Can I understand what that means for like everything? He 236 00:12:31,960 --> 00:12:34,920 Speaker 1: also swung for the fences. Yeah, he went cosmologically saying, hey, 237 00:12:34,960 --> 00:12:37,920 Speaker 1: it predicts his apple. Let's go for the universe. And 238 00:12:38,080 --> 00:12:39,679 Speaker 1: you only have to think about it for a moment 239 00:12:39,720 --> 00:12:43,120 Speaker 1: to realize, Well, if the Sun bends space or the 240 00:12:43,160 --> 00:12:45,480 Speaker 1: Earth moves around it, right, that means that mass and 241 00:12:45,600 --> 00:12:49,560 Speaker 1: energy is bending space sort of towards itself. Then what's 242 00:12:49,559 --> 00:12:51,079 Speaker 1: going to happen when you have a lot of masks, 243 00:12:51,120 --> 00:12:55,000 Speaker 1: like a universe sized blob of mass. Well, it's going 244 00:12:55,040 --> 00:12:58,160 Speaker 1: to cause things to contract, right, it's going to cause 245 00:12:58,320 --> 00:13:01,080 Speaker 1: things to contract. What do you mean, like it under 246 00:13:01,120 --> 00:13:03,400 Speaker 1: its own weight. Yeah, the gravity of all the stuff 247 00:13:03,400 --> 00:13:06,040 Speaker 1: in the universe should pull all the stuff together. Right. 248 00:13:06,440 --> 00:13:09,120 Speaker 1: If you're Einstein, you think, okay, I have an empty universe. 249 00:13:09,320 --> 00:13:12,520 Speaker 1: Space is flat. Then I add galaxies and stars and 250 00:13:12,559 --> 00:13:15,360 Speaker 1: gas and dust. What should happen, Well, space will bend 251 00:13:15,400 --> 00:13:17,680 Speaker 1: in a way to pull all that stuff eventually together. 252 00:13:17,720 --> 00:13:21,840 Speaker 1: And so in Einstein's universe, originally all that stuff should compact, 253 00:13:21,880 --> 00:13:24,480 Speaker 1: should fall into itself, and eventually create you know, like 254 00:13:24,520 --> 00:13:28,439 Speaker 1: a huge black hole. But do you need Einstein's gravity 255 00:13:28,679 --> 00:13:31,680 Speaker 1: formulation that way? Can what a Newton also predicted, everything 256 00:13:31,679 --> 00:13:33,959 Speaker 1: would just pull on itself and class Oh yeah, that's 257 00:13:33,960 --> 00:13:37,520 Speaker 1: a great question. Right now. In Newton's universe, you don't 258 00:13:37,640 --> 00:13:41,200 Speaker 1: necessarily get a collapse. I mean, you have gravity and 259 00:13:41,240 --> 00:13:44,960 Speaker 1: it's pulling stuff together. But in Newton's universe, space is flat, 260 00:13:45,000 --> 00:13:47,920 Speaker 1: and so it's possible for stuff to be arranged in 261 00:13:47,960 --> 00:13:50,880 Speaker 1: a way that's sort of stable in static like the 262 00:13:50,920 --> 00:13:53,640 Speaker 1: way that our planets orbit the Sun and don't collapse 263 00:13:53,880 --> 00:13:56,920 Speaker 1: the way our galaxy doesn't collapse because it's spinning. And 264 00:13:56,960 --> 00:13:59,800 Speaker 1: in Newton's time, remember they only knew about our galaxy, 265 00:13:59,840 --> 00:14:02,680 Speaker 1: that know about other galaxies out there, so even this 266 00:14:02,880 --> 00:14:07,040 Speaker 1: concept of the larger universe was not around. But for Einstein, 267 00:14:07,200 --> 00:14:09,319 Speaker 1: space can bend, and so even if things are in 268 00:14:09,440 --> 00:14:13,559 Speaker 1: stable orbits like they are here, they would still eventually collapse. 269 00:14:13,920 --> 00:14:17,840 Speaker 1: In fact, Einstein's calculations were done assuming that everything was 270 00:14:17,920 --> 00:14:21,240 Speaker 1: smoothly distributed, So even in the universe where gravity would 271 00:14:21,240 --> 00:14:24,200 Speaker 1: all cancel out like that, even in that scenario he 272 00:14:24,320 --> 00:14:28,560 Speaker 1: predicted that everything would collapse. So in Newton's universe things 273 00:14:28,640 --> 00:14:31,920 Speaker 1: could be arranged stable so they don't collapse, or Einstein, 274 00:14:32,040 --> 00:14:35,960 Speaker 1: without the cosmological constant, predicted everything would eventually collapse. But 275 00:14:36,120 --> 00:14:39,160 Speaker 1: that's a problem, right, This prediction, this consequence of his 276 00:14:39,240 --> 00:14:42,040 Speaker 1: theory or consequence of gravity, that the universe should be 277 00:14:42,040 --> 00:14:45,320 Speaker 1: like falling in on itself, is not what Einstein thought 278 00:14:45,360 --> 00:14:47,760 Speaker 1: was happening at the time, because back then, if you 279 00:14:47,840 --> 00:14:51,200 Speaker 1: looked out into the sky, things look pretty static, right, 280 00:14:51,240 --> 00:14:53,800 Speaker 1: nothing that nothing looks like it's trunching together. Yeah, back 281 00:14:53,800 --> 00:14:56,960 Speaker 1: in niften or so, people thought the universe was static, 282 00:14:57,000 --> 00:14:59,000 Speaker 1: that the stars are just hanging there in space and 283 00:14:59,040 --> 00:15:01,720 Speaker 1: there was no rel of motion, and things were just 284 00:15:01,720 --> 00:15:04,040 Speaker 1: sort of fixed. They've been that way forever, they would 285 00:15:04,080 --> 00:15:06,880 Speaker 1: be that way forever. Things look pretty peaceful. Yeah, And 286 00:15:06,960 --> 00:15:10,280 Speaker 1: so when Einstein came up with this theory and it 287 00:15:10,400 --> 00:15:12,640 Speaker 1: predicted that the universe should be falling in and itself, 288 00:15:12,640 --> 00:15:16,960 Speaker 1: he thought, oh, there must be something wrong, something must 289 00:15:17,000 --> 00:15:20,920 Speaker 1: be wrong with the universe or with his equations. Well, 290 00:15:21,160 --> 00:15:23,720 Speaker 1: he didn't doubt that the universe was static. He tried 291 00:15:23,760 --> 00:15:27,000 Speaker 1: to fudge his equations. He says, all right, well, if 292 00:15:27,040 --> 00:15:29,680 Speaker 1: the universe is not collapsing in itself, then I need 293 00:15:29,920 --> 00:15:33,360 Speaker 1: something to prevent it from collapse, something to push in 294 00:15:33,400 --> 00:15:36,320 Speaker 1: the other direction to keep its static, to balance. Because 295 00:15:36,400 --> 00:15:38,800 Speaker 1: if you apply his theory to the universe or just 296 00:15:38,960 --> 00:15:40,760 Speaker 1: really it doesn't have to be the universe, right, it 297 00:15:40,800 --> 00:15:43,840 Speaker 1: had just any collection of mass back at least in 298 00:15:43,880 --> 00:15:47,200 Speaker 1: the way that they thought space and mass was like 299 00:15:47,360 --> 00:15:49,640 Speaker 1: back then. Then that's sort of inevitable, right, if you 300 00:15:49,640 --> 00:15:52,640 Speaker 1: have gravity, everything's gonna come crunching down together. So he's like, wait, 301 00:15:52,680 --> 00:15:55,920 Speaker 1: that's not happening. So therefore I'm going to fudge my equation. Yeah, 302 00:15:55,920 --> 00:15:58,000 Speaker 1: he fudged it. He said, all right, so what I 303 00:15:58,080 --> 00:16:00,720 Speaker 1: need is something to balance gravity. So he has this 304 00:16:00,760 --> 00:16:05,200 Speaker 1: equation which predicts the basically the velocity how things will 305 00:16:05,240 --> 00:16:08,320 Speaker 1: move through space based on the matter and energy density. 306 00:16:08,360 --> 00:16:11,160 Speaker 1: And he just added another number with a minus sign 307 00:16:11,240 --> 00:16:13,560 Speaker 1: to to balance it out, to balance it out, to 308 00:16:13,720 --> 00:16:17,920 Speaker 1: make it match the idea of a universe that's not collapsing. Yeah, 309 00:16:17,960 --> 00:16:21,200 Speaker 1: he said, if there's some effect on gravity from mass 310 00:16:21,240 --> 00:16:24,240 Speaker 1: and energy, what if there's something else which is pushing 311 00:16:24,280 --> 00:16:28,880 Speaker 1: back something else which provides a counterbalancing influence so that 312 00:16:29,080 --> 00:16:31,760 Speaker 1: there is no overall gravity and so and so this 313 00:16:31,840 --> 00:16:34,240 Speaker 1: is his famous fudge factor, right, And did he call 314 00:16:34,320 --> 00:16:36,880 Speaker 1: it the cosmological concept or was that name given to 315 00:16:37,000 --> 00:16:40,240 Speaker 1: it afterwards? He called it the cosmological concept. He named 316 00:16:40,280 --> 00:16:44,120 Speaker 1: it capital lambda, and he chose this minus sign. And 317 00:16:44,160 --> 00:16:47,720 Speaker 1: there's no explanation for It's not like it comes from anything. 318 00:16:47,800 --> 00:16:50,640 Speaker 1: It's not like there's a bottoms of physics reason why 319 00:16:50,720 --> 00:16:53,880 Speaker 1: it should exist. It was really just added to try 320 00:16:54,000 --> 00:16:56,920 Speaker 1: to describe the universe that he was seeing interesting, all right, 321 00:16:56,960 --> 00:17:01,520 Speaker 1: And so this number has been described as sinds biggest blunder. 322 00:17:01,560 --> 00:17:03,680 Speaker 1: And so let's get into whether or not it was 323 00:17:03,720 --> 00:17:05,840 Speaker 1: a blunder or not and what that means. But first 324 00:17:05,920 --> 00:17:21,360 Speaker 1: let's take a quick break. All right, Daniel, did Einstein 325 00:17:21,440 --> 00:17:25,000 Speaker 1: commit a blunder or not when he introduced the cosmological 326 00:17:25,080 --> 00:17:27,560 Speaker 1: constant in his equations? What do you think? I think 327 00:17:27,600 --> 00:17:31,400 Speaker 1: it totally is a blunder, because well, it didn't even 328 00:17:31,480 --> 00:17:34,840 Speaker 1: really solve his problem. Like the problem he had was 329 00:17:34,880 --> 00:17:37,919 Speaker 1: that gravity was pulling in and he needed something to 330 00:17:37,960 --> 00:17:41,280 Speaker 1: be sort of pushing out. But the way he described it, 331 00:17:41,200 --> 00:17:43,679 Speaker 1: it was a very delicate balance, like he needed this 332 00:17:43,760 --> 00:17:46,800 Speaker 1: number to be exactly the right thing so that the 333 00:17:47,119 --> 00:17:49,520 Speaker 1: effect or gravity from mass would be balanced by the 334 00:17:49,520 --> 00:17:53,320 Speaker 1: effect of gravity from this weird cosmological constant. But it 335 00:17:53,359 --> 00:17:56,080 Speaker 1: doesn't work unless they're exactly balanced. But I guess why 336 00:17:56,080 --> 00:17:57,800 Speaker 1: do you call it a blunder? I mean, I just 337 00:17:57,880 --> 00:17:59,880 Speaker 1: think he's just being a good scient doesn't be like, oh, 338 00:18:00,040 --> 00:18:01,960 Speaker 1: I need something. I'm trying to a word with these 339 00:18:01,960 --> 00:18:04,560 Speaker 1: equations to make them fit when I'm observing. Therefore, I'm 340 00:18:04,560 --> 00:18:07,200 Speaker 1: going to add this. It's not like he maybe thought 341 00:18:07,440 --> 00:18:09,879 Speaker 1: something wrong, did he know? But my complaint is that 342 00:18:09,920 --> 00:18:12,600 Speaker 1: it doesn't even really work, Like if you actually had 343 00:18:12,640 --> 00:18:16,439 Speaker 1: a universe like that, then it wouldn't be static because 344 00:18:16,520 --> 00:18:19,240 Speaker 1: any little extra pocket of mass that was over dense, 345 00:18:19,480 --> 00:18:22,439 Speaker 1: like you know, a solar system whatever, would start this 346 00:18:22,640 --> 00:18:25,560 Speaker 1: runaway effect because it's not stable, like an extra pocket 347 00:18:25,640 --> 00:18:28,840 Speaker 1: of mass very quickly generates extra gravity and overcomes this 348 00:18:28,920 --> 00:18:32,720 Speaker 1: cosmological constant. And so while he wouldn't have like everything 349 00:18:32,840 --> 00:18:36,080 Speaker 1: drawing into the center, there would be lots of little collapses. Oh, 350 00:18:36,400 --> 00:18:39,520 Speaker 1: I see, his theory doesn't even really predict a static universe. 351 00:18:39,560 --> 00:18:42,920 Speaker 1: I see you're saying, putting it into the same equations 352 00:18:42,960 --> 00:18:45,919 Speaker 1: that he had before made a balance. But it's like 353 00:18:45,920 --> 00:18:50,560 Speaker 1: a super precarious and technically it only works if matters 354 00:18:50,680 --> 00:18:53,879 Speaker 1: totally evenly distributed through the universe and there's no extra 355 00:18:53,880 --> 00:18:57,080 Speaker 1: little spots of extra density, and if there are, then 356 00:18:57,080 --> 00:19:00,000 Speaker 1: those very rapidly coalesced. In collection doesn't know what happened. 357 00:19:00,040 --> 00:19:03,000 Speaker 1: The galaxies are in galaxies and planets really just like 358 00:19:03,080 --> 00:19:07,880 Speaker 1: small concentrations with mass, and so he's not describing what's happening, right, 359 00:19:08,200 --> 00:19:10,720 Speaker 1: He's trying to describe what he thought was happening, which 360 00:19:10,720 --> 00:19:14,400 Speaker 1: is a stable universe. But his description doesn't even lead 361 00:19:14,440 --> 00:19:17,080 Speaker 1: to a stable universe. You mean the whole equations wrong, 362 00:19:17,160 --> 00:19:19,920 Speaker 1: not just that constant. Yeah, I don't think the equation 363 00:19:20,000 --> 00:19:22,879 Speaker 1: is he put it together describes the static universe that 364 00:19:22,920 --> 00:19:24,760 Speaker 1: he was trying to describe, all right, So how did 365 00:19:24,800 --> 00:19:26,639 Speaker 1: they know it was a blunder? Well, I think it's 366 00:19:26,640 --> 00:19:29,000 Speaker 1: the blunder because it doesn't even describe the universe he 367 00:19:29,040 --> 00:19:31,960 Speaker 1: thought he was describing. But then it turns out that 368 00:19:32,000 --> 00:19:34,320 Speaker 1: the universe is different from what he thought, that the 369 00:19:34,400 --> 00:19:37,680 Speaker 1: universe is not static, right, that the universe he was 370 00:19:37,720 --> 00:19:40,399 Speaker 1: trying to describe suddenly shifted from under his feet, right, 371 00:19:40,400 --> 00:19:43,240 Speaker 1: because we now know that the universe is expanding, right, 372 00:19:43,359 --> 00:19:46,239 Speaker 1: that's right. Later on in the nineties, they discovered that 373 00:19:46,400 --> 00:19:49,080 Speaker 1: galaxies are actually moving apart from each other, that's right. Hubble, 374 00:19:49,160 --> 00:19:52,120 Speaker 1: building on work of various other people, discovered that there 375 00:19:52,119 --> 00:19:54,840 Speaker 1: are other galaxies out there and they're really far away, 376 00:19:55,000 --> 00:19:58,439 Speaker 1: and they're moving away from us faster and faster. So 377 00:19:58,480 --> 00:20:02,000 Speaker 1: he discovered that the universe not static, that it's expanding. 378 00:20:02,960 --> 00:20:05,160 Speaker 1: And so this would have blew up Einstein's idea because 379 00:20:05,160 --> 00:20:07,600 Speaker 1: he had worked carefully to add this number to his 380 00:20:07,640 --> 00:20:10,639 Speaker 1: equations to describe a static universe, and then it turns out, oops, 381 00:20:10,640 --> 00:20:14,720 Speaker 1: the universe not well, his problem was that he called 382 00:20:14,760 --> 00:20:17,159 Speaker 1: it a constant. Right if he had called it not, 383 00:20:17,600 --> 00:20:19,480 Speaker 1: or is it that they even did, the whole math 384 00:20:19,520 --> 00:20:21,479 Speaker 1: equation is wrong. I know. The problem is not that 385 00:20:21,480 --> 00:20:23,200 Speaker 1: he called it a constant that we can talk about 386 00:20:23,280 --> 00:20:26,199 Speaker 1: later about whether we think it's varying in time. The 387 00:20:26,280 --> 00:20:29,919 Speaker 1: problem is that he put this number in to fudge 388 00:20:29,920 --> 00:20:32,560 Speaker 1: his equation to describe a static universe, which is not 389 00:20:32,760 --> 00:20:35,440 Speaker 1: our universe. Okay, so we we don't live in a 390 00:20:35,480 --> 00:20:38,960 Speaker 1: static universe. Therefore any equation that assumes that is wrong. 391 00:20:39,080 --> 00:20:42,840 Speaker 1: That's right. And so then Einstein abandoned the cosmological constant, 392 00:20:43,160 --> 00:20:45,680 Speaker 1: and he never actually said it was his greatest blunder. 393 00:20:46,000 --> 00:20:48,280 Speaker 1: But after that he was definitely not a fan of it. 394 00:20:48,520 --> 00:20:51,600 Speaker 1: You know, he thought it was He was not well motivated, 395 00:20:51,640 --> 00:20:53,439 Speaker 1: and you sort of putting it in by hand, and 396 00:20:53,480 --> 00:20:55,640 Speaker 1: it doesn't come from anything. It doesn't really make sense. 397 00:20:55,800 --> 00:20:58,040 Speaker 1: I see. Well, he was pretty cool about it. Then 398 00:20:58,119 --> 00:21:00,399 Speaker 1: he didn't try to like hang onto it. And this 399 00:21:00,400 --> 00:21:03,480 Speaker 1: party is a little bit confusing because you might think, well, 400 00:21:03,560 --> 00:21:07,080 Speaker 1: Einstein put the cosmological constant in to prevent the universe 401 00:21:07,119 --> 00:21:10,159 Speaker 1: from collapsing in his model, but then he discovers the 402 00:21:10,200 --> 00:21:14,040 Speaker 1: universes expanding? How does he get rid of the cosmological constant? Right, 403 00:21:14,680 --> 00:21:18,440 Speaker 1: just put another number in it, a plus number. Well, 404 00:21:18,560 --> 00:21:21,919 Speaker 1: the cosmological constant already was pushing in that direction, right, 405 00:21:21,920 --> 00:21:25,160 Speaker 1: the cosmological constant. He had kept the universe from collapsing. 406 00:21:25,200 --> 00:21:28,560 Speaker 1: It was a positive repulsive force. Did you just make 407 00:21:28,600 --> 00:21:31,560 Speaker 1: that number bigger and will explain expansion? Right? And so 408 00:21:32,000 --> 00:21:35,400 Speaker 1: down the road, in order to explain expansion, accelerating expansion, 409 00:21:35,400 --> 00:21:37,439 Speaker 1: we're gonna have to make that number bigger. But what 410 00:21:37,440 --> 00:21:39,960 Speaker 1: Einstein did was get rid of it, right, not make 411 00:21:40,000 --> 00:21:42,440 Speaker 1: it bigger, but he just made it zero. He's like, oh, 412 00:21:42,440 --> 00:21:45,280 Speaker 1: this is wrong, and that seems confusing, right, because then 413 00:21:46,680 --> 00:21:49,320 Speaker 1: there are two things to keep in mind here at once, 414 00:21:49,440 --> 00:21:52,480 Speaker 1: the expansion, which is like a velocity, and then the 415 00:21:52,640 --> 00:21:55,640 Speaker 1: change in expansion, which is like an acceleration. Just like 416 00:21:55,680 --> 00:21:57,960 Speaker 1: in your car, you have a certain velocity and then 417 00:21:57,960 --> 00:22:00,919 Speaker 1: the engine or breaks gives you accelerating aation to change 418 00:22:01,000 --> 00:22:05,160 Speaker 1: that velocity. Now, the cosmological constant is more like the engine. 419 00:22:05,359 --> 00:22:09,600 Speaker 1: It gives acceleration to the expansion, either positive or negative. Now, 420 00:22:09,720 --> 00:22:13,600 Speaker 1: Einstein had originally assumed that the expansion velocity was zero, 421 00:22:13,640 --> 00:22:16,480 Speaker 1: that we lived in a static universe, and so he 422 00:22:16,680 --> 00:22:20,600 Speaker 1: set the cosmological constant to zero to also gave no acceleration. 423 00:22:21,000 --> 00:22:25,040 Speaker 1: So what Hubble discovered is that the expansion velocity was positive. 424 00:22:25,080 --> 00:22:29,080 Speaker 1: Hubble didn't measure the acceleration. He couldn't, so Einstein at 425 00:22:29,080 --> 00:22:32,679 Speaker 1: that point knew that his no expansion, no acceleration description 426 00:22:32,880 --> 00:22:37,200 Speaker 1: was wrong. Now, when Einstein tossed out the cosmological constant, 427 00:22:37,560 --> 00:22:40,840 Speaker 1: it gave him a universe with negative acceleration because gravity 428 00:22:40,880 --> 00:22:44,480 Speaker 1: was collapsing it, but it could still have positive expansion 429 00:22:44,520 --> 00:22:47,480 Speaker 1: velocity at that moment. It's sort of like driving at 430 00:22:47,560 --> 00:22:49,879 Speaker 1: high speeds at the same time as hitting the brakes 431 00:22:49,880 --> 00:22:54,919 Speaker 1: to slow you down. So no cosmological constant means negative acceleration, 432 00:22:54,960 --> 00:22:59,520 Speaker 1: which would eventually turn the universe's expansion around into a collapse. 433 00:23:00,000 --> 00:23:02,439 Speaker 1: But Einstein was more giving up on the whole idea 434 00:23:02,760 --> 00:23:05,680 Speaker 1: using the cosmological constant to get balanced and get zero 435 00:23:05,760 --> 00:23:12,840 Speaker 1: acceleration and zero velocity. So the cosmological constant um tells 436 00:23:12,880 --> 00:23:16,159 Speaker 1: you how how fast the expansion is changing. Yeah, okay, 437 00:23:16,240 --> 00:23:19,239 Speaker 1: And so by making it zero than Einstein thought that 438 00:23:19,280 --> 00:23:21,960 Speaker 1: he was saying, okay, it's expanding, but it's not accelerating, 439 00:23:22,160 --> 00:23:24,480 Speaker 1: it's not getting faster and fast. So Einstein's vision, I 440 00:23:24,480 --> 00:23:27,080 Speaker 1: think was the universe is expanding right now, but I'm 441 00:23:27,080 --> 00:23:29,720 Speaker 1: gonna get rid of the cosmological constant, which means that 442 00:23:29,800 --> 00:23:33,160 Speaker 1: expansion is decreasing. And so in the future Einstein thought 443 00:23:33,320 --> 00:23:37,000 Speaker 1: expansion would slow down, stop and eventually universe would still collapse. 444 00:23:37,400 --> 00:23:41,359 Speaker 1: Can't this Einstein guy get anything right? I mean, but 445 00:23:41,400 --> 00:23:42,959 Speaker 1: that he was kind of wrong about that too, right, 446 00:23:42,960 --> 00:23:46,080 Speaker 1: because later on, more recently, we discovered that the universe 447 00:23:46,160 --> 00:23:49,439 Speaker 1: is expanding faster and faster and faster. That's right, Hubble 448 00:23:49,560 --> 00:23:52,680 Speaker 1: was right, the universe is expanding, and the question was 449 00:23:53,080 --> 00:23:55,960 Speaker 1: is that expansion slowing down quickly or is that expansion 450 00:23:55,960 --> 00:23:59,040 Speaker 1: slowing down slowly? And we went out to measure it, 451 00:23:59,440 --> 00:24:02,600 Speaker 1: and this covered that neither of those are true. Right, 452 00:24:02,680 --> 00:24:06,080 Speaker 1: That the expansion is accelerating, that it's going faster and 453 00:24:06,160 --> 00:24:09,320 Speaker 1: faster every year, right, And we figured this out by 454 00:24:09,359 --> 00:24:13,000 Speaker 1: watching supernova's explode, which is let us understand how far 455 00:24:13,040 --> 00:24:16,000 Speaker 1: away things are and how fast they're moving away from us. 456 00:24:16,000 --> 00:24:18,919 Speaker 1: And we reconstructed this sort of history of the speed 457 00:24:19,040 --> 00:24:21,440 Speaker 1: the things are moving away from us, and that told 458 00:24:21,480 --> 00:24:23,719 Speaker 1: us that things are moving away from us faster and 459 00:24:23,760 --> 00:24:27,200 Speaker 1: faster every year. And so not only is hubble saw 460 00:24:27,440 --> 00:24:30,280 Speaker 1: is the universe expanding, but that expansion is getting faster 461 00:24:30,440 --> 00:24:33,840 Speaker 1: every year. Right. We We've had podcast episodes about this, 462 00:24:33,880 --> 00:24:37,000 Speaker 1: about the the idea that the universe is kind of exploding. Yeah, 463 00:24:37,119 --> 00:24:39,560 Speaker 1: the universe is sort of being torn apart, and it's 464 00:24:39,560 --> 00:24:42,680 Speaker 1: going through puberty or something. The most precise way to 465 00:24:42,680 --> 00:24:45,600 Speaker 1: think about it, I think, is that space is expanding, right, 466 00:24:45,640 --> 00:24:49,440 Speaker 1: We're creating new space between us and other galaxies. Right. 467 00:24:49,520 --> 00:24:53,240 Speaker 1: And a very common question from listeners is, if space 468 00:24:53,280 --> 00:24:55,960 Speaker 1: is being created between us and other galaxies, why isn't 469 00:24:55,960 --> 00:24:58,520 Speaker 1: it being created between us and the Sun, or between 470 00:24:58,520 --> 00:25:01,040 Speaker 1: me and you, or between in his banana, and and 471 00:25:01,080 --> 00:25:03,760 Speaker 1: it is. It's just that we're getting pulled together by gravity, 472 00:25:03,800 --> 00:25:06,199 Speaker 1: that's right. It is. It's being created equally everywhere. That's 473 00:25:06,200 --> 00:25:10,760 Speaker 1: why it's a cosmological constant. It's constant in space. Everywhere 474 00:25:10,800 --> 00:25:13,480 Speaker 1: in space is being stretched the same way. But as 475 00:25:13,520 --> 00:25:16,199 Speaker 1: you say, the Earth is holding you onto it, and 476 00:25:16,240 --> 00:25:19,280 Speaker 1: the Sun is holding us by its gravity, and our 477 00:25:19,280 --> 00:25:21,920 Speaker 1: galaxy is holding itself together even even like the air 478 00:25:21,960 --> 00:25:25,239 Speaker 1: inside of your mouth. Right now, is literally expanding, is 479 00:25:25,280 --> 00:25:29,400 Speaker 1: literally expanding. Yeah, everyone's brain is literally exploding right now, 480 00:25:30,119 --> 00:25:32,800 Speaker 1: not just because of us, that's right. And we call 481 00:25:32,920 --> 00:25:36,520 Speaker 1: this dark energy, right, but it's just physics shorthand for 482 00:25:36,760 --> 00:25:40,239 Speaker 1: we have no clue what's going on. This is, you know, 483 00:25:40,560 --> 00:25:43,600 Speaker 1: something we observe. We see that the universe is expanding, 484 00:25:43,880 --> 00:25:47,240 Speaker 1: and this is something we only discovered years ago. It's 485 00:25:47,480 --> 00:25:50,360 Speaker 1: mind blowing to realize that before that we were ignorant 486 00:25:50,359 --> 00:25:53,680 Speaker 1: of this really basic fact about our own EXAs well. 487 00:25:53,800 --> 00:25:56,120 Speaker 1: So I guess my question now is, then, is dark 488 00:25:56,200 --> 00:25:59,240 Speaker 1: energy related to the cosmological constant? You're sort of making 489 00:25:59,280 --> 00:26:02,080 Speaker 1: it sound like it's the same thing. Like what Einstein 490 00:26:02,160 --> 00:26:05,200 Speaker 1: was missing in his equation was the idea of dark 491 00:26:05,280 --> 00:26:08,320 Speaker 1: energy and that maybe this constant is related to it 492 00:26:08,480 --> 00:26:11,040 Speaker 1: or or is it totally separate. It's related to it, 493 00:26:11,119 --> 00:26:13,720 Speaker 1: and you know, the idea is you see something out 494 00:26:13,760 --> 00:26:16,159 Speaker 1: there in the universe, something you don't understand, which is 495 00:26:16,200 --> 00:26:19,560 Speaker 1: like the universe is expanding and that expansion is accelerating. 496 00:26:19,920 --> 00:26:24,200 Speaker 1: That's dark energy, just the observation that the expansion is accelerating. 497 00:26:24,440 --> 00:26:29,120 Speaker 1: No cosmological constant idea involved. Yet there's several possible explanations 498 00:26:29,160 --> 00:26:32,920 Speaker 1: for dark energy, one of which is the cosmological constant. Right, 499 00:26:33,080 --> 00:26:35,879 Speaker 1: how do you describe it? You want physics equations that 500 00:26:35,960 --> 00:26:37,920 Speaker 1: describe it so you can understand it, so you can 501 00:26:37,960 --> 00:26:41,080 Speaker 1: predict it. So you need to somehow describe it. And 502 00:26:41,119 --> 00:26:44,359 Speaker 1: so one way to describe that is to take Einstein's 503 00:26:44,359 --> 00:26:48,200 Speaker 1: field equations, which are awesome, and put the cosmological constant 504 00:26:48,520 --> 00:26:51,119 Speaker 1: back in, back in. So he put it back in. 505 00:26:51,280 --> 00:26:54,080 Speaker 1: He had taken it out, and now everyone is saying, no, no, wait, 506 00:26:54,840 --> 00:26:57,600 Speaker 1: don't take it out. It actually helps us understand what's 507 00:26:57,640 --> 00:26:59,359 Speaker 1: what's happening. That's right, and you need to put it 508 00:26:59,400 --> 00:27:02,359 Speaker 1: back in and put it back in larger than he did. Right. 509 00:27:02,600 --> 00:27:04,359 Speaker 1: He put it back in to try to balance the 510 00:27:04,440 --> 00:27:07,040 Speaker 1: universe on a knife edge to keep it static, and 511 00:27:07,080 --> 00:27:08,879 Speaker 1: then he pulled it out again. He's like, oh, the 512 00:27:08,920 --> 00:27:10,840 Speaker 1: universe is not static. I'll just let it collapse in 513 00:27:10,840 --> 00:27:12,960 Speaker 1: the future. Now we gotta put it back in and 514 00:27:13,000 --> 00:27:16,119 Speaker 1: crank it up so that it's accelerating the expansion to 515 00:27:16,160 --> 00:27:18,560 Speaker 1: the un Everyone's like, more fudge, Put more fudge in. 516 00:27:19,200 --> 00:27:22,400 Speaker 1: Don't put it in the fridge, just pour the whole 517 00:27:22,400 --> 00:27:24,359 Speaker 1: thing in. That's right. He put in some fudge. Then 518 00:27:24,400 --> 00:27:26,719 Speaker 1: he took the fudge out, and now we've doubled the fudge. 519 00:27:27,040 --> 00:27:30,879 Speaker 1: That's nice double fudge. It's a double fudged universe. Maybe 520 00:27:30,880 --> 00:27:33,560 Speaker 1: ein Steins Blunder was just picking the wrong ice cream flavor. 521 00:27:33,640 --> 00:27:36,719 Speaker 1: You never know. Alright, let's get into whether or not 522 00:27:36,800 --> 00:27:41,760 Speaker 1: this cosmological fudge constant is real and what that means 523 00:27:41,840 --> 00:27:44,200 Speaker 1: for the fate of the universe. But first let's take 524 00:27:44,240 --> 00:27:59,680 Speaker 1: a quick break. All right, we're talking about the cosmological 525 00:28:00,080 --> 00:28:02,800 Speaker 1: sin and we're talking about how it's something that Einstein 526 00:28:02,840 --> 00:28:05,120 Speaker 1: put in, then took out, and then people put back 527 00:28:05,160 --> 00:28:08,600 Speaker 1: in because it explains how the universe can be expanding 528 00:28:08,800 --> 00:28:11,760 Speaker 1: faster and faster. So it's kind of a real thing 529 00:28:12,000 --> 00:28:14,639 Speaker 1: because we're seeing it. But Daniel explain to us what 530 00:28:15,000 --> 00:28:19,120 Speaker 1: it actually is and like physically what it means, and 531 00:28:19,119 --> 00:28:21,720 Speaker 1: and how does it explain how the universe is expanding. Yeah, 532 00:28:21,720 --> 00:28:23,879 Speaker 1: so nobody knows the answer to any of those questions, 533 00:28:23,880 --> 00:28:25,960 Speaker 1: so we could just end the podcast, right, Well, then, 534 00:28:26,000 --> 00:28:28,520 Speaker 1: thank you very much, we'll end the podcast. It's a 535 00:28:28,560 --> 00:28:31,480 Speaker 1: fascinating question and it's something physicists or thinking about a lot, 536 00:28:31,680 --> 00:28:35,480 Speaker 1: and it's worth understanding what physicists do not yet understand. 537 00:28:36,000 --> 00:28:38,040 Speaker 1: And the first thing to know sort of the mechanics 538 00:28:38,080 --> 00:28:40,720 Speaker 1: of it, like how did he put it in? Well, 539 00:28:40,720 --> 00:28:43,560 Speaker 1: the the equations for john relativity are very complicated, but 540 00:28:43,600 --> 00:28:46,480 Speaker 1: you can solve them in some sort of simplifying assumptions 541 00:28:46,600 --> 00:28:48,760 Speaker 1: and you get like two equations, one that gives you 542 00:28:48,920 --> 00:28:50,960 Speaker 1: the expansion of the universe, the other that gives you 543 00:28:51,000 --> 00:28:53,480 Speaker 1: the acceleration. And if you look at those equations you 544 00:28:53,520 --> 00:28:55,720 Speaker 1: can google them later, you see that there's a term 545 00:28:55,760 --> 00:28:58,320 Speaker 1: there for mass and energy and that has one effect, 546 00:28:58,560 --> 00:29:01,120 Speaker 1: and he just literally put in a number with an 547 00:29:01,120 --> 00:29:06,040 Speaker 1: opposite sign to balance it. And so it's something Einstein's 548 00:29:06,080 --> 00:29:09,560 Speaker 1: description of mathematically would be something which has the opposite 549 00:29:09,600 --> 00:29:11,800 Speaker 1: gravitational effect of mass in it, and you have to 550 00:29:11,800 --> 00:29:14,720 Speaker 1: put it in a certain sort of solution of the equation. Yeah, 551 00:29:14,720 --> 00:29:16,160 Speaker 1: you have to put it into the equations in a 552 00:29:16,160 --> 00:29:18,680 Speaker 1: certain place, because it's not in like equals semc squared. 553 00:29:18,920 --> 00:29:21,600 Speaker 1: That's not where it is. It's somewhere else in the equation. 554 00:29:21,720 --> 00:29:23,720 Speaker 1: That's right, that's not the that equal s mc squared 555 00:29:23,800 --> 00:29:27,440 Speaker 1: is not part of Einstein's field equations for general relativity, 556 00:29:27,560 --> 00:29:30,680 Speaker 1: And so it goes into those field equations, and and 557 00:29:30,720 --> 00:29:32,520 Speaker 1: this is what we do in physics. We're like, all right, 558 00:29:32,680 --> 00:29:36,240 Speaker 1: this model, these equations describe what we see. Then what 559 00:29:36,320 --> 00:29:39,160 Speaker 1: does that mean? Right? The next step is interpretation, like 560 00:29:39,400 --> 00:29:41,520 Speaker 1: why is it like this and not something else? What 561 00:29:41,560 --> 00:29:44,160 Speaker 1: does that tell us about the universe that we need 562 00:29:44,200 --> 00:29:47,120 Speaker 1: this number here? Okay? So yeah, he people agree he 563 00:29:47,160 --> 00:29:49,080 Speaker 1: put it in the right place, but they don't agree 564 00:29:49,120 --> 00:29:51,440 Speaker 1: that it's actually a constant. Is it? Well, we don't know. 565 00:29:51,600 --> 00:29:54,120 Speaker 1: And the way you can interpret it sort of physically 566 00:29:54,440 --> 00:29:57,040 Speaker 1: is to think about it like maybe it's the energy 567 00:29:57,120 --> 00:30:01,920 Speaker 1: of empty space, right, because if space itself has some 568 00:30:02,160 --> 00:30:05,800 Speaker 1: energy inherent in it, then it could have this effects. Right, 569 00:30:05,840 --> 00:30:09,080 Speaker 1: So we're like searching for a physical explanation and this 570 00:30:09,120 --> 00:30:11,560 Speaker 1: could be totally wrong, right, This could be like, you know, 571 00:30:11,640 --> 00:30:14,040 Speaker 1: maybe the universe is made out of air, fire and water. 572 00:30:14,280 --> 00:30:17,600 Speaker 1: Could be that level of idea which peoples scots. But 573 00:30:17,800 --> 00:30:21,240 Speaker 1: we're just groping around in the dark here, and and 574 00:30:21,280 --> 00:30:22,680 Speaker 1: this is what we came up with. What you came 575 00:30:22,720 --> 00:30:25,240 Speaker 1: up with was that space is not space, and emptiness 576 00:30:25,320 --> 00:30:29,280 Speaker 1: is not empty. Noess, there's actually something in not an 577 00:30:29,320 --> 00:30:32,560 Speaker 1: empty space. There's something in empty space, and it's important 578 00:30:32,880 --> 00:30:35,880 Speaker 1: that this gets something really big, right if you think 579 00:30:35,880 --> 00:30:38,560 Speaker 1: of it as the energy of empty space, not as 580 00:30:38,760 --> 00:30:44,160 Speaker 1: something in space. Then as the universe expands, As space expands, 581 00:30:44,200 --> 00:30:47,000 Speaker 1: you get more space, you get more of this stuff. Right, 582 00:30:47,440 --> 00:30:49,960 Speaker 1: Because say you have like a cube of space and 583 00:30:50,000 --> 00:30:54,880 Speaker 1: it has two hydrogen molecules in it, and then it expands, right, Well, 584 00:30:54,880 --> 00:30:57,160 Speaker 1: you still only have two hydrogen molecules in it. So 585 00:30:57,400 --> 00:31:00,160 Speaker 1: the density of stuff in the universe is decreased, so 586 00:31:00,200 --> 00:31:03,280 Speaker 1: the gravitational effect of that stuff has decreased, but the 587 00:31:03,360 --> 00:31:07,200 Speaker 1: cosmological constant, the energy of empty space, is constant. So 588 00:31:07,280 --> 00:31:09,520 Speaker 1: you get twice as much space, you have twice as 589 00:31:09,600 --> 00:31:12,480 Speaker 1: much of this mysterious dark energy. It kind of sounds 590 00:31:12,520 --> 00:31:15,760 Speaker 1: like magic, Like you're like the you know, like the 591 00:31:15,800 --> 00:31:18,680 Speaker 1: total energy in the universe. You're just it just bubbles 592 00:31:18,760 --> 00:31:21,280 Speaker 1: up from like an infinite fountain. Yeah, it's pretty weird. 593 00:31:21,440 --> 00:31:24,320 Speaker 1: And gradually it's sort of takes over, Like as the 594 00:31:24,400 --> 00:31:27,000 Speaker 1: universe expands, you get more dark energy, and so the 595 00:31:27,040 --> 00:31:29,360 Speaker 1: fraction of the energy of the universe that's in dark 596 00:31:29,480 --> 00:31:32,280 Speaker 1: energy just grows and grows and grows and grows, and 597 00:31:32,560 --> 00:31:36,520 Speaker 1: eventually it's going to be totally dominant. Does that mean 598 00:31:36,520 --> 00:31:39,360 Speaker 1: that the energy of the universe is not being concerned. Well, 599 00:31:39,360 --> 00:31:41,239 Speaker 1: that's a whole other question. It's a great question. It's 600 00:31:41,280 --> 00:31:42,960 Speaker 1: pretty complicated. I think we should dive into that and 601 00:31:42,960 --> 00:31:45,960 Speaker 1: a whole other podcast. But the brief answer is that 602 00:31:46,040 --> 00:31:48,760 Speaker 1: the energy the universe might just be zero. So where's 603 00:31:48,760 --> 00:31:50,680 Speaker 1: all this new energy coming from. It's a lot of 604 00:31:50,720 --> 00:31:54,720 Speaker 1: negative energy in the universe that's bound up in gravitational interactions, 605 00:31:54,920 --> 00:31:57,960 Speaker 1: and so this new energy can be balanced by negative 606 00:31:58,040 --> 00:32:02,240 Speaker 1: energy of the gravitational interaction. That's uh, oh I see 607 00:32:02,240 --> 00:32:04,680 Speaker 1: when you create something, Oh I see, Like if you're 608 00:32:04,680 --> 00:32:07,800 Speaker 1: creating space between you and me, there's energy being created 609 00:32:07,840 --> 00:32:10,200 Speaker 1: by the space, but we're also sort of storing it 610 00:32:10,240 --> 00:32:14,680 Speaker 1: in the gravitational potential. Energy between negative energy in our 611 00:32:14,720 --> 00:32:18,560 Speaker 1: gravitational potential, because you need to add energy to free us. 612 00:32:18,640 --> 00:32:21,240 Speaker 1: Like if you have Daniel and Jorge orbiting each other, 613 00:32:21,760 --> 00:32:25,160 Speaker 1: we're bound together gravitationally. Then in order to make a 614 00:32:25,200 --> 00:32:27,320 Speaker 1: free Daniel and a free Johe, you need to add 615 00:32:27,440 --> 00:32:30,640 Speaker 1: energy to the system to pull it apart. Yeah, so 616 00:32:30,760 --> 00:32:34,400 Speaker 1: that means that that has negative energy. But it's weird 617 00:32:34,440 --> 00:32:36,680 Speaker 1: that the universe kind of wants that it wants to 618 00:32:36,720 --> 00:32:40,400 Speaker 1: free you, Daniel, why why didn't want what doesn't it 619 00:32:40,440 --> 00:32:42,360 Speaker 1: wanted to come to me? I don't know. I don't 620 00:32:42,360 --> 00:32:44,440 Speaker 1: know why the universe wants what it wants, But it's 621 00:32:44,480 --> 00:32:47,040 Speaker 1: it's weird to think about dark energy because it feels 622 00:32:47,040 --> 00:32:49,640 Speaker 1: like a strange coincidence, Like we are living at a 623 00:32:49,680 --> 00:32:52,400 Speaker 1: time when right now dark energy is about seventy percent 624 00:32:52,480 --> 00:32:54,960 Speaker 1: of the universe. We know eventually it's going to take over, 625 00:32:55,360 --> 00:32:57,160 Speaker 1: So why is it that we happen to live at 626 00:32:57,200 --> 00:33:00,640 Speaker 1: this time when like matter is thirty scent and dark 627 00:33:00,760 --> 00:33:04,480 Speaker 1: energy matter and radiation and all that stuff ist and 628 00:33:04,560 --> 00:33:06,880 Speaker 1: dark energy is sevent It feels like sort of a 629 00:33:06,920 --> 00:33:09,880 Speaker 1: weird balance. Really why? I mean like if we were 630 00:33:10,040 --> 00:33:12,760 Speaker 1: if the human race had come up a billion years ago, 631 00:33:12,840 --> 00:33:14,680 Speaker 1: we might be asking the same question, like, oh, why 632 00:33:14,720 --> 00:33:18,080 Speaker 1: is it six But if you look at the history 633 00:33:18,080 --> 00:33:20,920 Speaker 1: of the universe over a trillion years, only the very 634 00:33:20,920 --> 00:33:23,240 Speaker 1: first blip is going to have any sort of balance 635 00:33:23,280 --> 00:33:26,720 Speaker 1: between matter and dark energy. Most of it will be 636 00:33:26,760 --> 00:33:29,400 Speaker 1: dominated by dark energy. So even before us, you know, 637 00:33:29,640 --> 00:33:31,880 Speaker 1: the dark energy is the future, not the past, I guess. 638 00:33:31,920 --> 00:33:34,560 Speaker 1: I mean, like we're wondering why it is the way 639 00:33:34,560 --> 00:33:36,320 Speaker 1: it is like that now, But if we had been 640 00:33:36,320 --> 00:33:39,640 Speaker 1: born a billion years before, wouldn't it also be odd? 641 00:33:39,640 --> 00:33:41,600 Speaker 1: It would also be odd. Yeah, it's weird to find 642 00:33:41,600 --> 00:33:44,520 Speaker 1: two things in balance that won't stay in balance. Right. 643 00:33:44,600 --> 00:33:47,640 Speaker 1: We don't think that there's anything that's keeping dark energy 644 00:33:47,720 --> 00:33:50,600 Speaker 1: in balance with these other forces. Eventually it will take over, 645 00:33:51,040 --> 00:33:53,120 Speaker 1: and so it's just sort of weird to be alive 646 00:33:53,120 --> 00:33:55,640 Speaker 1: in a moment when it hasn't yet taken over because 647 00:33:55,720 --> 00:33:57,560 Speaker 1: most of the history of the universe. In the future 648 00:33:57,880 --> 00:33:59,920 Speaker 1: it will be in charge, but in the past there's 649 00:34:00,200 --> 00:34:04,000 Speaker 1: less or more less less because the universe is getting 650 00:34:04,040 --> 00:34:07,280 Speaker 1: more and more diluted, and so dark energy is growing 651 00:34:07,280 --> 00:34:10,280 Speaker 1: in important Okay, all right, so these are all related 652 00:34:10,280 --> 00:34:14,080 Speaker 1: to each other. The cosmological constant, the energy of empty space, 653 00:34:14,280 --> 00:34:16,759 Speaker 1: and dark energy. Are these all different names for the 654 00:34:16,800 --> 00:34:19,480 Speaker 1: same thing? Or I guess help me understand why we 655 00:34:19,520 --> 00:34:21,480 Speaker 1: have three names for it. Yeah, there's sort of three 656 00:34:21,560 --> 00:34:23,520 Speaker 1: layers of ideas there, and there's one more layer we 657 00:34:23,560 --> 00:34:27,920 Speaker 1: should be into. The dark energy is the description of 658 00:34:27,960 --> 00:34:31,440 Speaker 1: the accelerating expansion in the universe that's like experimental something 659 00:34:31,600 --> 00:34:33,840 Speaker 1: is out there doing this, as we call it dark energy. 660 00:34:34,440 --> 00:34:38,040 Speaker 1: The cosmological constant is an attempt to describe dark energy 661 00:34:38,440 --> 00:34:42,480 Speaker 1: using gravity, say well, maybe it's just a feature of gravity, right, Oh, 662 00:34:42,560 --> 00:34:44,480 Speaker 1: it could not be. It could not be, could be 663 00:34:44,520 --> 00:34:47,040 Speaker 1: something totally different. We could not need a cosmological constant. 664 00:34:47,040 --> 00:34:50,080 Speaker 1: And there's something that's probably different going on. Really, Oh 665 00:34:50,200 --> 00:34:52,839 Speaker 1: I see, I get it all right, Yeah, yeah, there 666 00:34:52,840 --> 00:34:55,200 Speaker 1: are other explanations for dark energy that don't involve the 667 00:34:55,239 --> 00:34:58,560 Speaker 1: cosmological constant. So the cosmological constant could still be zero, 668 00:34:58,640 --> 00:35:02,080 Speaker 1: like Einstein said, it coulds zero out here. See, you 669 00:35:02,080 --> 00:35:05,120 Speaker 1: guys were calling him a blunderer, and you don't even know. 670 00:35:06,040 --> 00:35:07,680 Speaker 1: I'm gonna I'm gonna go switch you over to t 671 00:35:07,840 --> 00:35:10,560 Speaker 1: mind Stein here and say maybe I'm gonna keep with him. 672 00:35:10,719 --> 00:35:13,520 Speaker 1: I think that's bananas. And the cosmological constants an attempt 673 00:35:13,520 --> 00:35:15,680 Speaker 1: to describe that, right, And then we go and say, well, 674 00:35:15,719 --> 00:35:18,880 Speaker 1: how can we explain the cosmological constant? If it exists, 675 00:35:18,960 --> 00:35:22,440 Speaker 1: if it's real, if it's there, what could be creating it? 676 00:35:22,719 --> 00:35:25,640 Speaker 1: This energy of empty space is an attempt to calculate 677 00:35:25,920 --> 00:35:29,719 Speaker 1: what the cosmological constant should be. Oh, I see, it's 678 00:35:29,760 --> 00:35:32,920 Speaker 1: a theory. It's a hypothesis built on a hypothesis of 679 00:35:32,920 --> 00:35:35,520 Speaker 1: a hypothesis, and because maybe it would work like if 680 00:35:35,560 --> 00:35:37,359 Speaker 1: you if you then sat down and said, all right, 681 00:35:37,960 --> 00:35:40,600 Speaker 1: what is the energy of empty space? And can I 682 00:35:40,640 --> 00:35:42,640 Speaker 1: calculate it? And if I get the right number, if 683 00:35:42,640 --> 00:35:44,400 Speaker 1: I get the number that actually measuring out there in 684 00:35:44,400 --> 00:35:47,799 Speaker 1: the universe, that suggests that I'm right right, Okay. So 685 00:35:47,840 --> 00:35:49,879 Speaker 1: they sat down and they said, all right, how much 686 00:35:50,000 --> 00:35:52,400 Speaker 1: energy do we expect there to be an empty space? 687 00:35:53,040 --> 00:35:55,319 Speaker 1: And you can calculate this because we know that there 688 00:35:55,320 --> 00:35:57,840 Speaker 1: are quantum fields out there in empty space, like the 689 00:35:57,920 --> 00:36:00,800 Speaker 1: Higgs field, which is not a zero. When the Higgs 690 00:36:00,800 --> 00:36:03,600 Speaker 1: field is at its lowest level, it's not at zero. 691 00:36:04,200 --> 00:36:06,719 Speaker 1: And we talked about this in another podcast. What would 692 00:36:06,719 --> 00:36:08,840 Speaker 1: happen if the Higgs field collapse down to zero and 693 00:36:09,000 --> 00:36:12,120 Speaker 1: destroy the universe. So we're we're lucky, We're happy that 694 00:36:12,160 --> 00:36:14,880 Speaker 1: the Higgs field is not at zero. But then if 695 00:36:14,920 --> 00:36:16,759 Speaker 1: you add up all the energy you think is stored 696 00:36:16,800 --> 00:36:18,879 Speaker 1: in the Higgs field and various other fields, you get 697 00:36:18,920 --> 00:36:21,440 Speaker 1: a number, and you compare that number to the number 698 00:36:21,640 --> 00:36:25,200 Speaker 1: that we measure for the cosmological constant, and they're different. 699 00:36:26,080 --> 00:36:28,960 Speaker 1: I see. So this idea that there's energy everywhere is 700 00:36:29,400 --> 00:36:32,280 Speaker 1: not unusual. You're saying that all of the quantum fields 701 00:36:32,280 --> 00:36:36,240 Speaker 1: have energy in them, and you're saying that they actually 702 00:36:36,239 --> 00:36:38,680 Speaker 1: have too much energy. Yeah, the number you get is 703 00:36:38,760 --> 00:36:41,520 Speaker 1: too big by a factor of ten to the one 704 00:36:41,600 --> 00:36:46,480 Speaker 1: hundred and twenty. Maybe Higgs is fudging it too, you know, 705 00:36:47,719 --> 00:36:50,840 Speaker 1: Higgs flavored fudge what that means? But could it be awesome? 706 00:36:50,880 --> 00:36:53,000 Speaker 1: Maybe like a field that we don't know about. Is 707 00:36:53,000 --> 00:36:55,959 Speaker 1: that possible to or like thinking like you know, maybe 708 00:36:56,000 --> 00:36:58,839 Speaker 1: these fields are leaking or something. Yeah, exactly. People say, well, 709 00:36:58,840 --> 00:37:01,680 Speaker 1: maybe there's another field there we haven't discovered, and it 710 00:37:01,880 --> 00:37:04,759 Speaker 1: happens to cancel all the other ones to give us 711 00:37:04,760 --> 00:37:08,560 Speaker 1: a really tiny number. And that's weird, right, Like, it's 712 00:37:08,600 --> 00:37:11,120 Speaker 1: weird if these two things balance each other to a 713 00:37:11,239 --> 00:37:14,520 Speaker 1: hundred and twenty decimal places to give us the number 714 00:37:14,560 --> 00:37:17,840 Speaker 1: the reasure, let's call it the fudge field, the fudge field. 715 00:37:18,360 --> 00:37:20,799 Speaker 1: And so that's not very satisfying, right, And then other 716 00:37:20,800 --> 00:37:23,000 Speaker 1: people say, well, who cares about those other fields? It 717 00:37:23,000 --> 00:37:24,719 Speaker 1: doesn't even have to be a field, doesn't even have 718 00:37:24,840 --> 00:37:26,880 Speaker 1: to be the energy of empty space. It can just 719 00:37:26,920 --> 00:37:30,839 Speaker 1: be a basic number of the universe, like maybe it's 720 00:37:30,840 --> 00:37:33,719 Speaker 1: just a parameter of the universe like a remainder or 721 00:37:33,800 --> 00:37:36,120 Speaker 1: just like a speed of light, you know, or the 722 00:37:36,160 --> 00:37:39,279 Speaker 1: planks constant. You know. Maybe there's just a number and 723 00:37:39,520 --> 00:37:43,879 Speaker 1: it's part of the universe. Yeah, yeah, exactly. And people 724 00:37:43,920 --> 00:37:46,239 Speaker 1: don't like that answer either, because then well why this 725 00:37:46,320 --> 00:37:49,120 Speaker 1: number and not any other number? And to answer that 726 00:37:49,200 --> 00:37:52,920 Speaker 1: you have to go multiverse, which is also unsatisfying. I 727 00:37:52,920 --> 00:37:56,759 Speaker 1: feel like we're stagging crazy hypothetical ideas one and top 728 00:37:56,800 --> 00:37:58,680 Speaker 1: of the other. How deep does this go, Daniel? This 729 00:37:58,719 --> 00:38:00,120 Speaker 1: is about as deep as it goes. Once you get 730 00:38:00,160 --> 00:38:02,520 Speaker 1: to the anthropic principle and the multiverse, you really can't 731 00:38:02,520 --> 00:38:05,120 Speaker 1: go deeper into the scientific bologna. You gotta throw your 732 00:38:05,120 --> 00:38:07,760 Speaker 1: heads up and be like, that's just the way it is. Folks. 733 00:38:07,800 --> 00:38:10,080 Speaker 1: Well you're drowning and scientific bologna at that point. So 734 00:38:10,400 --> 00:38:13,760 Speaker 1: we're out of fudge. That's it. We filled the pool 735 00:38:13,760 --> 00:38:15,760 Speaker 1: with fudge and we're in the deep end. Now, Well, 736 00:38:15,920 --> 00:38:18,920 Speaker 1: what is this anthropic principle? I think it means that 737 00:38:19,000 --> 00:38:21,080 Speaker 1: things are just the way they are, and we think 738 00:38:21,120 --> 00:38:23,520 Speaker 1: it's weird only because we happen to exist. Yeah. It 739 00:38:23,600 --> 00:38:26,680 Speaker 1: says when you have a random number, you can't explain. 740 00:38:26,800 --> 00:38:29,440 Speaker 1: It says, well, maybe there's an infinite number of universes, 741 00:38:29,480 --> 00:38:32,319 Speaker 1: and each one has a different random number, and only 742 00:38:32,360 --> 00:38:34,600 Speaker 1: in the universes where that random number happens to be 743 00:38:34,719 --> 00:38:37,480 Speaker 1: what it is, so that you can't have intelligent life? 744 00:38:37,600 --> 00:38:40,640 Speaker 1: Do you have intelligent life asking why is that number? 745 00:38:40,640 --> 00:38:45,240 Speaker 1: What I see? There are other universes where this cosmological 746 00:38:45,320 --> 00:38:49,120 Speaker 1: constant is different, but there's nobody around to ask the question. Yeah, 747 00:38:49,200 --> 00:38:52,560 Speaker 1: if on those other universes the cosmological constant was some 748 00:38:52,600 --> 00:38:55,680 Speaker 1: crazy big number and the universe just like exploded in 749 00:38:55,719 --> 00:38:58,800 Speaker 1: the first bill a second and no interesting structure formed, 750 00:38:58,800 --> 00:39:01,919 Speaker 1: and you didn't get you know, awesome podcasts asking about 751 00:39:01,960 --> 00:39:04,320 Speaker 1: the nature of the universe, or maybe there are universes 752 00:39:04,360 --> 00:39:07,000 Speaker 1: where you know that there are the two guys having 753 00:39:07,040 --> 00:39:10,240 Speaker 1: a podcast. They're wondering, I wonder why pie is seven 754 00:39:10,280 --> 00:39:13,839 Speaker 1: point six. They must live in a different geometrical space then, 755 00:39:14,320 --> 00:39:18,000 Speaker 1: But yeah, and I find that answer totally unsatisfying because 756 00:39:18,040 --> 00:39:20,880 Speaker 1: it's kind of like saying there is no answer, stop asking, 757 00:39:22,560 --> 00:39:24,440 Speaker 1: And that's not who I am. You know, I'm always 758 00:39:24,800 --> 00:39:27,160 Speaker 1: asking questions. I always want to dig deeper. I just 759 00:39:27,200 --> 00:39:29,560 Speaker 1: want to know why. You're like, I'm sure Einstein was wrong. 760 00:39:29,800 --> 00:39:33,279 Speaker 1: I know it. I'm pretty sure Einstein was wrong. I 761 00:39:33,320 --> 00:39:36,239 Speaker 1: have to go on team not Einstein. Oh I see 762 00:39:36,280 --> 00:39:40,240 Speaker 1: anti Einstein. Oh man. I mean I'm pro Eenstein in general, 763 00:39:40,280 --> 00:39:42,120 Speaker 1: but in this one, I don't think you guys right? 764 00:39:42,920 --> 00:39:44,840 Speaker 1: All right, well, I think that clears it up a 765 00:39:44,880 --> 00:39:47,200 Speaker 1: lot for me. How all these things are related. Um, 766 00:39:47,239 --> 00:39:49,560 Speaker 1: so let me try to recap then. So we know 767 00:39:49,600 --> 00:39:53,080 Speaker 1: the universe is expanding, and we call that dark energy. 768 00:39:53,239 --> 00:39:56,719 Speaker 1: We know the universe expanding, and its expansion is accelerated, right, 769 00:39:56,760 --> 00:39:59,080 Speaker 1: It's getting faster and faster, and we don't know what 770 00:39:59,160 --> 00:40:01,319 Speaker 1: it is in any of our equations. We just call 771 00:40:01,320 --> 00:40:03,959 Speaker 1: it dark energy, and so we have a theory about 772 00:40:03,960 --> 00:40:06,480 Speaker 1: what it could be, and maybe it's due to gravity, 773 00:40:06,480 --> 00:40:10,120 Speaker 1: and so that's where the cosmological constant comes in. And 774 00:40:10,160 --> 00:40:13,280 Speaker 1: then we don't have a good explanation for the cosmological constants, 775 00:40:13,320 --> 00:40:14,799 Speaker 1: so we just poured a lot of fudge in it 776 00:40:14,880 --> 00:40:18,880 Speaker 1: and then call it. Call it the energy of not energy. 777 00:40:19,080 --> 00:40:25,279 Speaker 1: And that's right, the fudge of empty space. All right? Well, um, 778 00:40:25,320 --> 00:40:27,399 Speaker 1: and I think it's been pretty interesting that to think 779 00:40:27,440 --> 00:40:29,920 Speaker 1: about these huge questions about the universe, you know, and 780 00:40:29,960 --> 00:40:32,600 Speaker 1: how how ay we don't know what's going on and 781 00:40:32,640 --> 00:40:35,319 Speaker 1: be how you know, even people like Einstein are sort 782 00:40:35,360 --> 00:40:38,200 Speaker 1: of grasping it strong sometimes. That's right, And we made 783 00:40:38,200 --> 00:40:40,239 Speaker 1: a little bit of fun of science here for having 784 00:40:40,239 --> 00:40:43,320 Speaker 1: silly ideas. But you know, this is how real science 785 00:40:43,360 --> 00:40:45,840 Speaker 1: gets done. When you're on the forefront of human ignorance, 786 00:40:45,960 --> 00:40:48,040 Speaker 1: you try crazy stuff and you say, well, maybe it's 787 00:40:48,120 --> 00:40:50,080 Speaker 1: something like this. Can we make this work? Can we 788 00:40:50,160 --> 00:40:52,960 Speaker 1: make that work? Because you know, the universe is ridiculous, 789 00:40:53,280 --> 00:40:56,319 Speaker 1: and so no ridiculous ideas should be discarded because it 790 00:40:56,440 --> 00:40:59,560 Speaker 1: might be correct, it might be accurate, it might describe 791 00:40:59,640 --> 00:41:02,920 Speaker 1: our ridiculous reality. This is the best we can do, folks. 792 00:41:03,280 --> 00:41:05,480 Speaker 1: It's a process, right, you want to join in the fun, 793 00:41:05,800 --> 00:41:08,680 Speaker 1: Go study physics, that's right. If you've ever done any writing, 794 00:41:08,719 --> 00:41:11,399 Speaker 1: you know the rough draft is always pretty roub. And 795 00:41:11,840 --> 00:41:15,160 Speaker 1: that's where we are now. All right, Well, thank you 796 00:41:15,280 --> 00:41:17,799 Speaker 1: very much to Pascal for asking this question, and we 797 00:41:17,840 --> 00:41:20,239 Speaker 1: hope that helps you sleep a little bit better at night. 798 00:41:20,280 --> 00:41:23,040 Speaker 1: That's right, And remember that the biggest questions in the universe, 799 00:41:23,160 --> 00:41:26,359 Speaker 1: about the biggest universe out there are still unsolved, which 800 00:41:26,400 --> 00:41:29,239 Speaker 1: means you might be the person to figure them out. 801 00:41:29,280 --> 00:41:39,120 Speaker 1: Thanks for joining us. See you next time before you 802 00:41:39,200 --> 00:41:42,040 Speaker 1: still have a question after listening to all these explanations, 803 00:41:42,160 --> 00:41:44,799 Speaker 1: please drop us a line. We'd love to hear from you. 804 00:41:45,080 --> 00:41:47,960 Speaker 1: You can find us on Facebook, Twitter, and Instagram at 805 00:41:48,239 --> 00:41:51,439 Speaker 1: Daniel and Jorge That's one Word, or email us at 806 00:41:51,680 --> 00:41:55,360 Speaker 1: Feedback at Daniel and Jorge dot com. Thanks for listening 807 00:41:55,360 --> 00:41:58,080 Speaker 1: and remember that Daniel and Jorge Explain the Universe is 808 00:41:58,120 --> 00:42:01,719 Speaker 1: a production of I Heart Ready More podcast for my 809 00:42:01,840 --> 00:42:05,400 Speaker 1: Heart Radio. Visit the I Heart Radio app, Apple Podcasts, 810 00:42:05,560 --> 00:42:11,759 Speaker 1: or wherever you listen to your favorite shows. H