WEBVTT - What is quantum relativity? 0:00:08.600 --> 0:00:10.760 Hey, Katie, are you a fan of Italian food? 0:00:11.119 --> 0:00:13.880 Well? I live in Italy, so here we just call 0:00:13.920 --> 0:00:14.560 it food. 0:00:14.880 --> 0:00:19.520 But yeah, all right, Well what about Italian American food? 0:00:19.600 --> 0:00:23.160 You know, the version made by Italian immigrants to America. 0:00:23.440 --> 0:00:24.400 Yeah, no, I like it. 0:00:24.400 --> 0:00:28.360 It's more meatballs and more garlic, but that's still really good. 0:00:28.520 --> 0:00:31.920 Well what about the opposite, what about American Italian food? 0:00:32.200 --> 0:00:37.080 So is that cuisine made by American immigrants who are 0:00:37.120 --> 0:00:37.760 in Italy? 0:00:38.400 --> 0:00:38.600 Yeah? 0:00:38.720 --> 0:00:39.559 Basically you. 0:00:40.159 --> 0:00:44.199 Well, I mean I mostly just have coffee and toast, 0:00:44.400 --> 0:00:46.440 which would be a really short cookbook. 0:00:48.080 --> 0:00:50.120 Maybe you should try innovating. Have you ever tried putting 0:00:50.120 --> 0:00:51.280 a meatball in your coffee? 0:00:51.960 --> 0:00:55.480 I know I have not tried to do that, Daniel. 0:00:55.960 --> 0:00:57.440 Could be a cultural revolution. 0:00:57.680 --> 0:01:14.440 Well, it would indeed be revolting. 0:01:15.680 --> 0:01:15.880 Hi. 0:01:16.000 --> 0:01:19.160 I'm Daniel. I'm a particle physicist and a professor at 0:01:19.280 --> 0:01:22.160 uc Ervine, and I don't like anything in my coffee, 0:01:22.319 --> 0:01:23.480 definitely not meatballs. 0:01:23.800 --> 0:01:25.399 Hi. I am Katie. 0:01:25.560 --> 0:01:30.080 I host a podcast called Creature feature on evolutionary biology, 0:01:30.240 --> 0:01:34.520 and I like a huge amount of sugar in my coffee. 0:01:34.880 --> 0:01:40.440 So we could see how that is with meatballs as well. Well. 0:01:40.440 --> 0:01:43.280 That makes me wonder since you're a biologist, tell me 0:01:43.520 --> 0:01:46.640 who are the natural consumers of coffee? Like, who out 0:01:46.680 --> 0:01:49.120 there in the animal world is eating coffee beans off 0:01:49.120 --> 0:01:49.480 the tree. 0:01:49.800 --> 0:01:54.680 That's the thing is that coffee caffeine in coffee plants 0:01:54.760 --> 0:02:00.560 is meant to be slightly toxic to insects that want 0:02:00.640 --> 0:02:04.080 to eat it. And it's the same story for spicy foods. 0:02:04.120 --> 0:02:08.280 It's actually defense mechanism, and so the insects that will 0:02:08.320 --> 0:02:13.160 try to eat these plants will not farewell. But when 0:02:13.160 --> 0:02:16.480 we have it, it's actually delicious and good. Now, there 0:02:16.560 --> 0:02:21.160 are palm civets who will eat types of coffee plants. 0:02:21.800 --> 0:02:26.760 They eat the berries, and there's actually a coffee drink 0:02:26.919 --> 0:02:31.919 made out of the beans collected from the palm civet hoop. 0:02:32.320 --> 0:02:34.799 And it's very expensive. 0:02:34.960 --> 0:02:35.160 Wow. 0:02:35.200 --> 0:02:37.360 I don't know what blows my mind more there the 0:02:37.400 --> 0:02:40.480 fact that we are sipping insect poison, or the fact 0:02:40.520 --> 0:02:43.440 that that whole strategy has backfired on the coffee tree 0:02:43.520 --> 0:02:46.880 because it attracts us, or how quickly a biologist will 0:02:46.880 --> 0:02:48.480 turn the conversation towards poop. 0:02:50.680 --> 0:02:52.639 The latter is the least surprising. 0:02:54.440 --> 0:02:56.800 That is, in the end, where we overlap the darkest 0:02:56.880 --> 0:03:01.120 matters in the Universe and Welcome the podcast Daniel and 0:03:01.200 --> 0:03:05.280 Jorge Explain the Universe the production of iHeartRadio, in which 0:03:05.280 --> 0:03:08.280 we try to do just that. Explore everything that's out 0:03:08.320 --> 0:03:12.320 there in the universe, ask our deepest, darkest questions about 0:03:12.360 --> 0:03:15.079 who is sipping which bits of the universe and why 0:03:15.120 --> 0:03:18.360 they exist in that way? What are the tiniest particles 0:03:18.480 --> 0:03:20.600 that everything is made out of, What are the rules 0:03:20.600 --> 0:03:23.080 by which they play? How do they come together to 0:03:23.120 --> 0:03:26.040 make civets and cats and poops and coffee and biologists 0:03:26.080 --> 0:03:29.560 who wonder about all those things combined? Is it possible 0:03:29.600 --> 0:03:32.760 to understand and explain the universe? We're going to try. 0:03:33.040 --> 0:03:34.920 That is the first thing I think of when I 0:03:34.920 --> 0:03:39.880 think about civt kat poop is the tiniest of particles 0:03:40.560 --> 0:03:44.760 that make up that coffee. But yeah, I mean, I guess, 0:03:44.800 --> 0:03:49.040 I guess when you can go down really really tiny, 0:03:49.320 --> 0:03:51.960 and that makes things like poop less gross because now 0:03:52.560 --> 0:03:56.880 you're just on the atomic level and these are just atoms. 0:03:56.920 --> 0:03:58.840 They don't smell. Atoms don't smell bad. 0:03:58.960 --> 0:04:01.960 I don't think, well, does it make poop less gross 0:04:02.000 --> 0:04:04.280 to think that it's made of the same basic building 0:04:04.280 --> 0:04:06.560 blocks as everything else, or does it make everything else 0:04:06.800 --> 0:04:10.040 more gross to know that ice cream and lava and 0:04:10.120 --> 0:04:12.120 kittens are made out of the same stuff as poop. 0:04:14.560 --> 0:04:17.800 Interesting question, ice cream, lava. 0:04:20.360 --> 0:04:22.840 Let's put a pin in that. But let's dive deep 0:04:22.960 --> 0:04:25.800 into what the universe is made out of. One of 0:04:25.839 --> 0:04:28.600 our deepest questions in physics, and a question that humans 0:04:28.640 --> 0:04:31.880 have been asking basically since humans have been asking questions, 0:04:32.400 --> 0:04:35.240 is how do things work at the smallest scale? Is 0:04:35.279 --> 0:04:38.719 it possible to zoom down on what's around us and 0:04:38.800 --> 0:04:41.919 explain things in simpler and simpler terms, Because you know, 0:04:42.040 --> 0:04:44.160 you start out with a huge number of things out 0:04:44.200 --> 0:04:47.039 there in the universe blueberries and cats and ice cream 0:04:47.080 --> 0:04:50.920 and coffee and biologists and physicists and everything in between. 0:04:51.200 --> 0:04:54.120 It's an incredible variety. But when you dig down a 0:04:54.120 --> 0:04:56.599 little bit, you discover, oh, everything out there is made 0:04:56.640 --> 0:04:59.880 out of about one hundred basic building blocks the elements 0:05:00.160 --> 0:05:04.520 periodic table. Combined in different ways, you can make essentially everything. 0:05:04.640 --> 0:05:07.160 And even that set of one hundred building blocks is 0:05:07.200 --> 0:05:10.360 made out of an even smaller set of stuff. Right, 0:05:10.400 --> 0:05:14.560 Protons and neutrons and electrons make up all of those atoms, 0:05:15.040 --> 0:05:17.400 which means that the same stuff can be used to 0:05:17.440 --> 0:05:20.440 make lava or kittens, or ice cream or poops, or 0:05:20.480 --> 0:05:24.800 biologists or stars. All that stuff is made out of 0:05:24.839 --> 0:05:25.560 the same thing. 0:05:26.120 --> 0:05:29.560 It's interesting because I do know that one of the 0:05:29.600 --> 0:05:33.320 things that unites kittens and lava and poop is that 0:05:33.400 --> 0:05:38.840 it all obeys the laws of physics. If you throw 0:05:38.880 --> 0:05:41.200 a kitten in some lava, you're going to have a 0:05:41.279 --> 0:05:44.440 predictable result because of the laws of physics. Both the 0:05:44.560 --> 0:05:49.039 kitten and the lava are constrained by the laws of physics. 0:05:49.240 --> 0:05:52.800 But the thing that's interesting to me, and that hurts 0:05:52.839 --> 0:05:55.599 my brain a little bit, is that when you look 0:05:55.720 --> 0:06:00.520 at say like a very tiny quantum part of it 0:06:00.560 --> 0:06:03.640 does not necessarily obey the same laws of physics as 0:06:03.720 --> 0:06:06.920 say a marble. So you know, I think of like 0:06:06.960 --> 0:06:11.040 a marble bonking into another marble. I can somewhat understand 0:06:11.080 --> 0:06:14.000 how that works. But then you go down small enough 0:06:14.400 --> 0:06:18.240 and it's not just tiny atomic marbles bonking into each other. 0:06:18.920 --> 0:06:21.520 Weird stuff happens that blows my mind. 0:06:21.880 --> 0:06:24.279 It is incredible that the laws of physics seem to 0:06:24.320 --> 0:06:27.560 be different at different scales, like at different distances or 0:06:27.640 --> 0:06:31.440 different energies. It seems like different rules apply, like to 0:06:31.600 --> 0:06:35.640 baseballs and to electrons. The rules are fundamentally different. There 0:06:35.640 --> 0:06:37.840 are different kinds of stuff and the rules that apply 0:06:37.880 --> 0:06:39.800 to them are different, and that does feel weird, and 0:06:39.800 --> 0:06:42.320 it's one of the most incredible things about the universe. 0:06:42.400 --> 0:06:44.120 But a helpful way to think about it is in 0:06:44.200 --> 0:06:47.919 terms of phases, Like think about water. Water has a 0:06:47.960 --> 0:06:50.480 liquid phase and a solid phase and a gas phase. 0:06:50.560 --> 0:06:52.120 Right in the end, we think it's all made out 0:06:52.120 --> 0:06:54.719 of the same basic stuff water molecules, but they act 0:06:54.920 --> 0:06:58.360 very differently under different circumstances. And you wouldn't expect the 0:06:58.400 --> 0:07:00.720 laws of an ideal gas to describe what happens when 0:07:00.720 --> 0:07:04.320 water crystallizes, or fluid dynamics to explain how a gas 0:07:04.360 --> 0:07:08.599 would expand different rules apply in different scenarios, different phases, 0:07:08.839 --> 0:07:11.360 And so we imagine that the universe is organized the 0:07:11.400 --> 0:07:13.240 same way you can think of You can think of 0:07:13.240 --> 0:07:15.840 it as sort of different phases where different rules apply. 0:07:16.520 --> 0:07:19.520 What we don't know is if there is an underlying 0:07:19.680 --> 0:07:22.960 theory behind all of it, the sort of physics version 0:07:23.080 --> 0:07:26.520 of the water molecule, the tiniest little bits who's dancing 0:07:26.560 --> 0:07:29.680 and tuing and froing and interacting is somehow making all 0:07:29.760 --> 0:07:33.760 this other stuff emerge, even the quantum particles, even the baseballs, 0:07:33.840 --> 0:07:37.440 even the galaxies. Is there something at the lowest level 0:07:37.480 --> 0:07:41.360 which is determining everything from which all of our experience emerges. 0:07:42.000 --> 0:07:45.440 So this is an interesting and confusing question to me, 0:07:45.560 --> 0:07:50.720 because from my understanding, if we're all in the same universe, 0:07:51.200 --> 0:07:55.800 we would all regardless of whether we're a human or 0:07:56.040 --> 0:07:59.440 a quark or a kitten, we'd have to play by 0:07:59.480 --> 0:08:01.160 the same rules. 0:08:01.640 --> 0:08:03.480 But if the rules are. 0:08:04.080 --> 0:08:07.480 Different somehow, right, like for a quark versus a kitten 0:08:08.200 --> 0:08:10.360 in terms of physics, even though the kitten is also 0:08:10.600 --> 0:08:15.080 made out of quarks or atoms molecules, it's hard for 0:08:15.120 --> 0:08:18.560 me to wrap my head around there not being a 0:08:19.320 --> 0:08:23.640 unifying set of rules that applies to everything, given that 0:08:24.120 --> 0:08:26.600 not only do we live in the same universe, but 0:08:26.640 --> 0:08:29.400 we're made out of all the same stuff. 0:08:29.760 --> 0:08:32.839 Yeah, it's a great question, and a basic assumption about 0:08:32.880 --> 0:08:35.360 a lot of physics is that that's possible that if 0:08:35.400 --> 0:08:37.800 you zoom down to the smallest scale, you can find 0:08:37.800 --> 0:08:40.000 the most basic set of rules, and that then you 0:08:40.040 --> 0:08:43.079 could somehow zoom back out with the fundamental theory of 0:08:43.080 --> 0:08:46.480 the universe in hand, you could explain everything it might 0:08:46.520 --> 0:08:48.840 require you to calculate, like how ten to the twenty 0:08:48.920 --> 0:08:51.640 nine particles come together to make a baseball. But the 0:08:51.679 --> 0:08:55.240 idea is, in principle, it's all determined by what's happening 0:08:55.280 --> 0:08:58.000 at the smaller scale, and when you zoom out, that's 0:08:58.040 --> 0:09:00.600 just what those laws look like. And it might be 0:09:00.679 --> 0:09:02.880 the case, right It might be that even though we 0:09:02.960 --> 0:09:06.760 have trouble explaining how a zillion water droplets interacting in 0:09:06.800 --> 0:09:09.200 the atmosphere make a hurricane, we can't even do it 0:09:09.200 --> 0:09:12.920 with our fastest supercomputers. We think that probably it is 0:09:13.040 --> 0:09:17.160 determined by that, but that's actually a philosophical assumption, and 0:09:17.240 --> 0:09:20.560 some philosophers of science disagree with that. It's called strong 0:09:20.720 --> 0:09:23.360 emergence at some point to lots of things that we 0:09:23.440 --> 0:09:27.160 can't explain using underlying details. A great example is like 0:09:27.559 --> 0:09:31.160 why you are here your consciousness. We have completely failed 0:09:31.200 --> 0:09:34.280 so far to explain the experience of human consciousness in 0:09:34.400 --> 0:09:36.960 terms of like the zapping of the little neurons inside 0:09:37.000 --> 0:09:39.920 of our brains. It might be that somehow all that 0:09:39.960 --> 0:09:42.680 stuff comes together to explain why you are experiencing this 0:09:42.760 --> 0:09:45.680 podcast right now. But it might also be that there 0:09:45.720 --> 0:09:48.920 are just different rules at different levels of the universe 0:09:49.240 --> 0:09:52.280 that aren't actually determined by the lower levels, that somehow 0:09:52.320 --> 0:09:56.000 there are independent layers of the universe and different rules 0:09:56.040 --> 0:09:58.960 apply at each one. It's a weird philosophy of the universe, 0:09:59.040 --> 0:10:01.439 but it might also be our universe. 0:10:01.280 --> 0:10:05.280 That's very hard for my conscious brain to wrap itself around. 0:10:05.400 --> 0:10:09.880 It is very interesting, this philosophical question of consciousness because 0:10:10.280 --> 0:10:14.080 if we apply sort of the rules of like, well, 0:10:14.120 --> 0:10:17.840 a brain works right because you have a communication between 0:10:17.880 --> 0:10:21.400 many parts, you have neurons that are all communicating with 0:10:21.480 --> 0:10:24.120 each other and forming these networks. Well, there's a lot 0:10:24.120 --> 0:10:28.720 of things that do that, from computers to ant colonies, 0:10:29.320 --> 0:10:33.480 and so the question is, well, are those things conscious 0:10:33.520 --> 0:10:35.880 as well? And we can't really quantify that, and we 0:10:35.960 --> 0:10:39.960 can't know whether even though it seems like there's this 0:10:40.080 --> 0:10:43.960 underlying rule of you know, you require these sort of 0:10:43.960 --> 0:10:47.559 individual units that are all communicating together and forming patterns, 0:10:47.600 --> 0:10:50.160 and that's what you need for consciousness. If you see 0:10:50.160 --> 0:10:54.280 that repeated in other systems, whether that actually applies to say, 0:10:54.320 --> 0:10:59.000 can you recreate a consciousness with an electronic version of 0:10:59.280 --> 0:11:02.679 neurons or or is something like a very complex ant 0:11:02.720 --> 0:11:04.280 colony with thousands of ants? 0:11:04.320 --> 0:11:08.199 Does that recreate consciousness. So I guess in a way. 0:11:08.200 --> 0:11:12.800 I could see how there could be different rules applying 0:11:12.840 --> 0:11:18.240 to different layers, but it's just so strange and so like. Currently, 0:11:18.800 --> 0:11:22.680 when we look at like quantum mechanics, it does not 0:11:22.880 --> 0:11:26.920 do a good job of explaining physics on a larger scale. 0:11:27.240 --> 0:11:30.640 Mostly we cannot connect the layers that we have. Even 0:11:30.679 --> 0:11:34.920 though that's basically the motivation for the project to understand 0:11:34.920 --> 0:11:37.280 everything at the smallest scale and use that to explain 0:11:37.360 --> 0:11:41.880 everything else that's bigger, we have very rarely succeeded in 0:11:42.000 --> 0:11:45.959 using a zoomed in microscopic approach to explain anything bigger. 0:11:46.040 --> 0:11:46.160 You know. 0:11:46.240 --> 0:11:50.160 One famous success story is ideal gases. Is say, okay, 0:11:50.160 --> 0:11:52.480 we have this picture of atoms moving in a gas 0:11:52.559 --> 0:11:55.120 as tiny little balls. Can we zoom out and think 0:11:55.160 --> 0:11:58.440 about what happens to ten to the twenty nine balls, 0:11:58.440 --> 0:12:01.920 and can we write equations that tell mathematical stories about 0:12:01.960 --> 0:12:05.040 things that emerge from ten to the twenty nine tiny 0:12:05.080 --> 0:12:08.120 little gas molecules like pressure and temperature and volume, and 0:12:08.240 --> 0:12:11.120 we can you can actually derive, like the ideal gas 0:12:11.280 --> 0:12:15.280 law from statistical mechanics explanations about the velocities of those 0:12:15.320 --> 0:12:18.199 tiny little particles. That's a famous example because it's one 0:12:18.200 --> 0:12:21.040 of the rare successes. Mostly we have failed because the 0:12:21.120 --> 0:12:24.680 universe is kind of chaotic. It's really sensitive often to 0:12:24.840 --> 0:12:27.920 these tiny little details. What happens to this quantum particle 0:12:27.920 --> 0:12:31.240 affects another quantum particle, which affects another quantum particle. We 0:12:31.280 --> 0:12:34.040 don't understand how to do that calculation. Most of the time, 0:12:34.160 --> 0:12:36.040 we don't have the computing power, and we can't avoid 0:12:36.040 --> 0:12:39.000 this chaos problem. So mostly we don't know how to 0:12:39.080 --> 0:12:41.640 do that. It might be that it is determined and 0:12:41.679 --> 0:12:43.880 it's possible to do those calculations, is just sort of 0:12:44.160 --> 0:12:47.200 beyond our ability right now. Or it might be that 0:12:47.280 --> 0:12:50.360 it's just not that different rules apply in different regimes, 0:12:50.400 --> 0:12:51.800 as weird as that is. 0:12:52.280 --> 0:12:56.520 So, I guess I'm not so familiar with quantum mechanics 0:12:56.600 --> 0:13:01.440 and general relativity. Can we kind of just hammer down, 0:13:01.480 --> 0:13:04.560 like what are those two things? How Like what do 0:13:04.600 --> 0:13:06.640 they apply to and what don't they apply to? 0:13:07.160 --> 0:13:09.360 So at the forefront of our understanding of the most 0:13:09.559 --> 0:13:13.320 microscopic picture of how the universe works, we have two 0:13:13.360 --> 0:13:16.560 basic theories. We have quantum mechanics, which tells us about 0:13:16.559 --> 0:13:19.240 really tiny stuff, and general relativity, which tells us about 0:13:19.320 --> 0:13:23.240 really big, heavy stuff, basically quantum mechanics for particles and 0:13:23.320 --> 0:13:26.480 general relativity for gravity. One of the biggest frustrations in 0:13:26.480 --> 0:13:29.240 physics in the last one hundred years has been our 0:13:29.280 --> 0:13:32.520 inability to bring them together into a single story, to 0:13:32.640 --> 0:13:35.840 weave them into a unified picture of how the universe works. 0:13:36.000 --> 0:13:38.200 You know, this whole project of like, let's explain everything 0:13:38.200 --> 0:13:40.560 from the tiniest particles and then zoom out. Well, we 0:13:40.600 --> 0:13:43.400 haven't even succeeded in explaining the tinese particles yet, but 0:13:43.440 --> 0:13:46.360 there's a vigorous program of people working on this stuff. 0:13:46.400 --> 0:13:48.840 And in today's episode, we're going to dig into one 0:13:48.880 --> 0:13:52.320 of the most recent and weirdest ideas about how to 0:13:52.360 --> 0:13:56.400 bring quantum mechanics and relativity together. So on today's episode, 0:13:56.440 --> 0:14:05.760 we're going to be answering the question, what is quantum relativity? 0:14:05.960 --> 0:14:11.480 Hmmm, quantum relativity. So it's like quantum mechanics and general 0:14:11.520 --> 0:14:13.480 relativity had a baby. 0:14:15.720 --> 0:14:18.360 It also sounds like the buzzword name for a startup 0:14:18.360 --> 0:14:19.880 where you're like, I don't even really know what it 0:14:20.000 --> 0:14:23.600 they do, but it sounds pretty good. So before we 0:14:23.600 --> 0:14:25.680 dig into the details of this, I checked in with 0:14:25.720 --> 0:14:28.720 our listeners to see if they had any idea about 0:14:28.720 --> 0:14:32.680 the theory of quantum relativity, if they had heard this before, 0:14:32.720 --> 0:14:34.840 if they had thoughts about it. Thanks very much to 0:14:34.880 --> 0:14:38.840 everybody who participates in this audience feedback segment of the podcast. 0:14:38.880 --> 0:14:41.360 We really love hearing your voice and hearing your thoughts 0:14:41.360 --> 0:14:43.640 on the question of the day. If you would like 0:14:43.680 --> 0:14:45.960 to participate, please don't be shy. Just write to me 0:14:46.280 --> 0:14:50.360 to Questions at Danielandjorge dot com and I'll hook you up. 0:14:50.920 --> 0:14:53.840 So before you hear these answers, think to yourself, have 0:14:53.920 --> 0:14:57.760 you heard of quantum relativity? What do you think that 0:14:57.880 --> 0:15:00.600 might mean. Here's what some listeners have to say. 0:15:00.880 --> 0:15:02.040 Quantum relativity. 0:15:02.800 --> 0:15:06.680 I'm guessing that is the theory that brings quantum mechanics 0:15:06.680 --> 0:15:12.560 and general relativity together. So something that the theory that 0:15:13.880 --> 0:15:17.560 figures out how you work gravity and quantum mechanics together. 0:15:17.680 --> 0:15:20.640 Since gravity, we're not quite sure how that works on 0:15:20.680 --> 0:15:22.280 the smallest scales. 0:15:22.720 --> 0:15:25.160 That is really really tiny relativity. 0:15:25.800 --> 0:15:29.520 To me, that sounds like a parallel to general relativity. 0:15:29.840 --> 0:15:32.520 So I bet that it has to do with how 0:15:32.600 --> 0:15:36.040 particles interact with each other when in proximity to each 0:15:36.040 --> 0:15:37.720 other on a quantum scale. 0:15:37.920 --> 0:15:42.240 I love the answer really tiny relativity because it makes 0:15:42.280 --> 0:15:46.000 me think of some ants or some mites or tartar 0:15:46.040 --> 0:15:49.560 grades in the lab coats drawing on tiny chalkboards. 0:15:51.640 --> 0:15:55.480 Exactly. Also, quantum just sometimes means like fancy or stinazzi, 0:15:55.680 --> 0:15:57.880 or we're going to charge an extra ten bucks for it, 0:15:57.960 --> 0:16:00.560 So like expensive relativity. 0:16:00.240 --> 0:16:05.560 This is a quantum salad for twelve dollars, exactly. 0:16:06.400 --> 0:16:09.000 I'd like to upgrade my salad, actually do a quantum salad. 0:16:09.720 --> 0:16:11.760 Or I ordered quantum on my salad and I didn't 0:16:11.800 --> 0:16:12.240 get enough. 0:16:13.720 --> 0:16:14.800 Could mean anything thanks in. 0:16:14.800 --> 0:16:19.040 A complaint anything. Well, we're going to see today. The 0:16:19.160 --> 0:16:22.040 quantum relativity is the name of a new effort to 0:16:22.280 --> 0:16:25.520 unify quantum mechanics and general relativity, and they really do 0:16:25.600 --> 0:16:28.840 give it that name for a reason. But before that's 0:16:28.880 --> 0:16:30.400 going to make any sense to us, we really have 0:16:30.440 --> 0:16:33.120 to understand the basics of like what is quantum mechanics 0:16:33.120 --> 0:16:35.480 in general relativity, why do we want to unify them, 0:16:35.840 --> 0:16:37.520 and why is it so hard? 0:16:38.080 --> 0:16:38.400 Right? 0:16:38.640 --> 0:16:42.680 Yes, because, like you were kind of saying earlier, general 0:16:42.680 --> 0:16:44.520 relativity is for big stuff. 0:16:44.600 --> 0:16:46.800 Quantum mechanics is for tiny stuff. 0:16:47.080 --> 0:16:49.480 But it's got to be a little more detailed than 0:16:49.480 --> 0:16:51.600 that I would imagine. 0:16:52.040 --> 0:16:55.120 No, that's basically it take quantu mechanics, generativity. It's like 0:16:55.160 --> 0:16:58.080 all done in fifteen minutes. But listeners of the podcast 0:16:58.120 --> 0:17:02.120 will remember that general relativity based describes space and time. 0:17:02.280 --> 0:17:05.600 Special relativity is a theory that tells us about how 0:17:05.680 --> 0:17:08.760 light moves and how observers always see light moving at 0:17:08.760 --> 0:17:12.560 the same speed, and general relativity is what explains gravity. 0:17:13.000 --> 0:17:15.560 Remember Newton had the idea that gravity was a force 0:17:15.840 --> 0:17:18.760 that things with mass pulled on each other and that's 0:17:18.760 --> 0:17:21.000 why the Earth goes around the Sun and you feel 0:17:21.040 --> 0:17:24.120 like you're falling towards the Earth because he described gravity 0:17:24.160 --> 0:17:27.320 as this force. But Einstein tells us that gravity is 0:17:27.400 --> 0:17:30.920 not a force. A gravity is not capable of accelerating anything, 0:17:31.280 --> 0:17:34.280 and that things are actually moving according to the invisible 0:17:34.440 --> 0:17:36.359 curvature of space and time. 0:17:36.720 --> 0:17:38.919 This is the thing that is so hard for me 0:17:39.560 --> 0:17:43.600 to really visualize or hold in my head because every 0:17:43.720 --> 0:17:48.600 kind of analogy I try to make is based in physics, 0:17:48.680 --> 0:17:52.399 like a ball rolling down a hill or something, or 0:17:53.160 --> 0:17:56.200 you know, I think of the fabric of space being 0:17:56.240 --> 0:17:58.600 sort of pulled in a certain direction, and it's like 0:17:58.680 --> 0:18:00.719 that's still physics. In the sun and so of like 0:18:01.320 --> 0:18:05.080 you know, a fabric being pulled and something falling into it. 0:18:05.440 --> 0:18:09.280 Whereas like the idea of gravity being sort of the 0:18:09.440 --> 0:18:13.800 shape of the universe in a way that like makes 0:18:13.800 --> 0:18:16.560 sense in my head is very hard to grasp. I 0:18:16.640 --> 0:18:19.399 understand it in a certain way, but to visualize it 0:18:19.440 --> 0:18:20.480 is so difficult. 0:18:20.640 --> 0:18:23.960 It is very tricky because it changes your entire concept 0:18:24.000 --> 0:18:25.280 of what space is. 0:18:25.960 --> 0:18:26.080 Right. 0:18:26.119 --> 0:18:28.479 We used to thinking of space as like nothingness and 0:18:28.640 --> 0:18:31.679 stuff is there and it can move through space. But 0:18:31.720 --> 0:18:34.800 it turns out that there is something to space, like 0:18:34.880 --> 0:18:39.040 between two points, there's information information about how that space 0:18:39.160 --> 0:18:42.520 is curved or bent, and that affects how stuff moves 0:18:42.600 --> 0:18:45.160 through that space. And yeah, there's a lot of examples 0:18:45.160 --> 0:18:47.600 out there in popular science literature. I think most of 0:18:47.600 --> 0:18:50.080 which are very confusing. You know, the idea of like 0:18:50.119 --> 0:18:52.800 a rubber sheet and you have a ball on the sheet, 0:18:53.080 --> 0:18:55.600 and the rubber sheet is bent and that makes things curved. 0:18:55.680 --> 0:18:57.920 That's very confusing because you still have to have gravity 0:18:57.920 --> 0:19:00.359 in that example in the vertical direction. You have this 0:19:00.440 --> 0:19:03.480 like external third dimension of gravity in your two D world. 0:19:03.520 --> 0:19:06.040 I think that's very very misleading. I prefer to think 0:19:06.040 --> 0:19:08.639 about it in three D. And remember that this curvature 0:19:08.720 --> 0:19:12.440 is intrinsic. It's not external. It's not like there's somebody 0:19:12.520 --> 0:19:15.800 else out there with a ruler in real space who's 0:19:15.800 --> 0:19:18.520 telling us our space is bent relative to their space. 0:19:18.680 --> 0:19:21.720 The curvature is intrinsic. There's no external ruler. It just 0:19:21.800 --> 0:19:25.720 means that the relative distances between two points change, which 0:19:25.760 --> 0:19:28.920 means like the shortest path from A to B might 0:19:28.960 --> 0:19:32.000 not be a straight line that you would draw if 0:19:32.040 --> 0:19:34.760 you ignore the curvature. Once you know what the curvature is, 0:19:34.800 --> 0:19:37.240 there might be a shorter path between A and B, 0:19:37.600 --> 0:19:39.760 and that's the path that light will take. Light always 0:19:39.800 --> 0:19:42.480 takes the shortest path between two points. 0:19:42.960 --> 0:19:46.679 So if I'm standing on my bed and I'm going 0:19:46.760 --> 0:19:48.679 to jump off the bed, as I do every morning, 0:19:48.920 --> 0:19:53.199 so I am subject to the gravity of Earth, and 0:19:53.280 --> 0:19:56.720 it's not so much that it's pulling me down, but 0:19:56.960 --> 0:20:00.600 just that I am traveling along the short this path 0:20:00.640 --> 0:20:03.720 from point A, which is my bed, to point B, 0:20:04.000 --> 0:20:07.439 which is the other point of space. But it's more 0:20:07.520 --> 0:20:09.399 or less just interrupted by the floor. 0:20:09.800 --> 0:20:12.800 Yeah, that's a great example. Let's think about it first 0:20:12.800 --> 0:20:15.600 from the Newtonian point of view, and then let's reboot 0:20:15.600 --> 0:20:17.560 and think about it from an Einsteinian point of view. 0:20:17.920 --> 0:20:20.720 So Newton would say, you're standing on your bed. There's 0:20:20.760 --> 0:20:23.159 the force of gravity pulling down on you from the Earth, 0:20:23.440 --> 0:20:25.560 and there's the force of your bed pushing up, and 0:20:25.600 --> 0:20:27.880 those two things are balanced, so you're not going anywhere. 0:20:27.960 --> 0:20:30.280 Then you jump off your bed. No longer is the 0:20:30.320 --> 0:20:32.640 bed pushing you up, and so now you're falling because 0:20:32.640 --> 0:20:35.040 it's just the force of gravity, and that's accelerating you 0:20:35.080 --> 0:20:36.760 down towards the center of the Earth. That's the way 0:20:36.760 --> 0:20:39.439 people mostly learn about gravity. That's how Newton described it. 0:20:39.480 --> 0:20:43.800 That's where we start. Einstein says something different. Einstein says, well, 0:20:43.800 --> 0:20:47.040 when you're standing on your bed, you actually are being accelerated. 0:20:47.040 --> 0:20:49.879 There's only one force there. There's the force of your bed. 0:20:50.160 --> 0:20:52.640 What's it pushing you against. It's pushing you against your 0:20:52.720 --> 0:20:56.280 natural motion, which is to fall towards the center of 0:20:56.320 --> 0:20:59.399 the earth. So Newton says, you're accelerating when after you 0:20:59.480 --> 0:21:01.720 jump off the bed and you're falling towards the center. 0:21:01.920 --> 0:21:04.440 Einstein says, no, you were accelerating when you were on 0:21:04.480 --> 0:21:07.159 your bed. It's when you jump off your bed that 0:21:07.240 --> 0:21:11.080 you're now following the natural curvature of space. You're no 0:21:11.160 --> 0:21:14.719 longer accelerating. The only force in this scenario is the 0:21:14.760 --> 0:21:17.959 force of the bed on you, and that's keeping you 0:21:18.000 --> 0:21:20.560 from naturally moving towards the center of the Earth. When 0:21:20.600 --> 0:21:23.360 you're standing on the bed. Once you jump off, you're 0:21:23.440 --> 0:21:25.800 the one in free fall. And you can actually measure 0:21:25.840 --> 0:21:28.960 this because you can take an accelerometer, something which measures 0:21:28.960 --> 0:21:32.440 your acceleration. I mean, the scale is basically a gravitometer, 0:21:33.000 --> 0:21:35.840 and you can measure when are you feeling an acceleration. 0:21:36.000 --> 0:21:37.840 If you jump off your bed and you're holding a scale, 0:21:37.920 --> 0:21:39.600 you put it under your feet, what are you going 0:21:39.640 --> 0:21:41.639 to weigh? You're going to weigh nothing because there's no 0:21:41.720 --> 0:21:44.479 force between you and the scale. But if the scale's 0:21:44.480 --> 0:21:46.280