WEBVTT - What is quantized inertia? 0:00:08.560 --> 0:00:11.039 Good morning, or hey, have you left the house yet today? 0:00:11.440 --> 0:00:14.040 I have? Yeah, I record in my garage. I have 0:00:14.080 --> 0:00:16.599 a set up there, so thankfully I'm out of the house. 0:00:16.720 --> 0:00:19.439 But if you mean like leaving the premises of my house, no, 0:00:19.520 --> 0:00:21.680 I haven't done that yet. I mean it's not even noon. 0:00:21.800 --> 0:00:24.960 Who leaves the house before noon? M I guess most 0:00:25.000 --> 0:00:28.040 of humanity have that experience. Are you saying I'm not 0:00:28.120 --> 0:00:30.800 part of humanity? I'm just saying maybe you have more 0:00:30.880 --> 0:00:35.440 inertia than the rest of us. Yes, Hey, cartoonists, address 0:00:35.440 --> 0:00:38.479 tends to stay in rest less than external deadline is 0:00:38.479 --> 0:00:41.160 applied to it. Yeah, I think that's Newton's forgotten fourth 0:00:41.240 --> 0:00:44.479 law of cartooning physics forgotten or he never got to 0:00:44.479 --> 0:00:47.040 it because he had too much inertia he never managed 0:00:47.080 --> 0:01:04.120 to change out of his pajamas. Yeah, Hi am for 0:01:04.240 --> 0:01:08.160 handy cartoonists and the creator of PhD comics. Hi. I'm Daniel. 0:01:08.200 --> 0:01:11.680 I'm a particle physicist and a professor at UC Irvine, 0:01:11.840 --> 0:01:14.319 and I have my own kind of inertia. Oh yeah, 0:01:14.400 --> 0:01:16.560 is it mostly around your waist or you have a 0:01:16.640 --> 0:01:20.880 very inertial head. It's sort of more conceptual inertia. Once 0:01:20.920 --> 0:01:22.840 I have an idea, I don't like to let go 0:01:22.920 --> 0:01:25.160 of it, so the idea has inertia though, Is that 0:01:25.200 --> 0:01:27.160 what you mean? Is it a heavy idea or a 0:01:27.240 --> 0:01:30.399 light idea? It's sort of stubbornly sticks around in my brain. 0:01:30.760 --> 0:01:33.199 Sometimes I'll get curious about something and it just will 0:01:33.240 --> 0:01:36.800 not leave me for months or years, until eventually I 0:01:36.880 --> 0:01:39.920 find an answer. Aren't you describing all physicists though? Is 0:01:39.959 --> 0:01:42.800 a nurse a certain sense amount of compulsion that you 0:01:42.840 --> 0:01:45.200 need to be a you know, a researcher, a scientist. 0:01:45.240 --> 0:01:47.600 I think there is in fact a minimum quantum level 0:01:47.720 --> 0:01:50.760 of obsession you have to have in order to dedicate 0:01:50.800 --> 0:01:53.440 your life to these crazy ideas. Well. Welcome to our 0:01:53.440 --> 0:01:57.840 podcast Daniel and Jorge explain the Universe, hopefully your new obsession, 0:01:58.360 --> 0:02:00.880 which is a production of our heart, in which we 0:02:00.920 --> 0:02:05.680 explore the entire universe without leaving our houses or changing 0:02:05.720 --> 0:02:09.000 out of our pajamas. We help you perform the incredible 0:02:09.040 --> 0:02:12.160 feat of trying to import the entire universe, all of 0:02:12.160 --> 0:02:16.160 the stars and galaxies and tiny particles and alien landscapes 0:02:16.200 --> 0:02:19.480 that might be out there, into your brain without ever 0:02:19.639 --> 0:02:22.160 leaving your home. If you're lying in bed or sitting 0:02:22.200 --> 0:02:25.079 on your couch or otherwise chilling out. We hope to 0:02:25.120 --> 0:02:28.160 bring the entire universe to you. That's right, because it 0:02:28.240 --> 0:02:31.640 is a pretty heavy universe, full of massive and amazing 0:02:32.160 --> 0:02:35.839 revelations and things to discover. Did we try to fit 0:02:35.919 --> 0:02:38.960 all inside of your head. It's a big project to 0:02:39.120 --> 0:02:42.280 understand how the universe works, and something we've been working 0:02:42.320 --> 0:02:46.560 on for a long time, decades, centuries, even millennia. If 0:02:46.560 --> 0:02:50.240 you take seriously early Greek physics, which you don't write, 0:02:50.720 --> 0:02:53.880 I've seen you talk about Greek physicists, or as you 0:02:54.040 --> 0:02:56.080 like to call them, Greek guess you know, they had 0:02:56.120 --> 0:02:59.160 a different approach. They began by thinking internally just what 0:02:59.320 --> 0:03:02.920 made sense to them. The concept of empiricism came a 0:03:03.000 --> 0:03:06.280 little bit later, actually going out and testing these ideas 0:03:06.360 --> 0:03:09.000 to see if they do describe our universe is a 0:03:09.080 --> 0:03:12.240 little bit more modern than the ancient Greeks. I feel 0:03:12.280 --> 0:03:14.080 like it's a little bit unfair though, because like, you 0:03:14.080 --> 0:03:16.000 know a lot more than them, but only because there 0:03:16.000 --> 0:03:18.800 were a lot of people who did signs and research 0:03:18.840 --> 0:03:21.560 before you did. Like if you were born in Greek times, 0:03:21.600 --> 0:03:23.880 who knows what you might be thinking. Oh, that's definitely true, 0:03:23.919 --> 0:03:27.560 and I don't claim to be smarter than Aristotle or Galileo. 0:03:27.800 --> 0:03:29.520 I think the lesson to take away from it is 0:03:29.560 --> 0:03:33.400 that progress is slow, and the things that seem obvious 0:03:33.480 --> 0:03:37.680 to us were actually big intellectual steps forward, and we 0:03:37.760 --> 0:03:41.160 can't really recognize that anymore because we are so marinated 0:03:41.200 --> 0:03:43.680 in our current way of thinking. We forget how big 0:03:43.680 --> 0:03:46.880 an intellectual leap it was to try to describe the 0:03:46.960 --> 0:03:49.920 universe in terms of mathematics and make predictions and go 0:03:49.960 --> 0:03:52.680 out and test those things. All of that was a 0:03:52.720 --> 0:03:55.840 big idea that took thousands of years to bubble up 0:03:56.000 --> 0:03:58.960 from inside human brains. Yeah, although it all seems like 0:03:59.080 --> 0:04:02.120 Greek to me, there is a lot of scientists have 0:04:02.200 --> 0:04:04.760 discovered and theorize about the universe, and we've made a 0:04:04.840 --> 0:04:07.280 huge amount of progress. We have a pretty solid theory 0:04:07.320 --> 0:04:09.840 about what things are made out of and also how 0:04:09.880 --> 0:04:12.240 the stars and the galaxies and the black holes out 0:04:12.280 --> 0:04:14.960 there moved. It is kind of incredible how much progress 0:04:15.040 --> 0:04:18.919 we have made. Our mastery of technology is evidence that 0:04:19.000 --> 0:04:22.039 we understand how the universe works at a very microscopic 0:04:22.120 --> 0:04:25.159 scale all the way up to a macroscopic scale. We 0:04:25.200 --> 0:04:28.080 can use computers which are based on the motions of 0:04:28.120 --> 0:04:31.440 tiny little particles to guide enormous things like a seven 0:04:31.520 --> 0:04:35.440 forty seven across the ocean. It's this harmony between the 0:04:35.520 --> 0:04:37.760 very very small and the very very big. We have 0:04:37.880 --> 0:04:41.039 explored the universe at all of these scales and many 0:04:41.160 --> 0:04:43.799 scales in between, and at each step we can find 0:04:43.920 --> 0:04:47.440 some story to tell about what's going on, how things work, 0:04:47.520 --> 0:04:50.520 what laws they seem to be following. It never ceases 0:04:50.520 --> 0:04:53.720 to amaze me that the universe is understandable. It is 0:04:53.760 --> 0:04:56.599 pretty amazing. Although even though we have theories that can 0:04:56.600 --> 0:04:59.120 predict things like the motion of particles and the motion 0:04:59.160 --> 0:05:02.159 of galaxies in stars out there in space, that doesn't 0:05:02.160 --> 0:05:05.400 necessarily mean that we understand these theories or what they 0:05:05.400 --> 0:05:07.279 mean or where they come from. Yeah, we tell a 0:05:07.279 --> 0:05:11.119 little mathematical stories about the universe, but sometimes it's useful 0:05:11.160 --> 0:05:13.640 to stop and say, like, what is this thing we 0:05:13.680 --> 0:05:17.239 are talking about anyway? Like we have the Shorteninger equation 0:05:17.279 --> 0:05:19.640 that tells us the wave function of a particle and 0:05:19.720 --> 0:05:22.280 how it moves through space, but it leaves unanswered important 0:05:22.360 --> 0:05:26.200 questions like well, what is a particle anyway? And it 0:05:26.200 --> 0:05:30.359 turns out that physicists and philosophers have riotously different opinions 0:05:30.400 --> 0:05:33.400 about what this thing is we're talking about. But we 0:05:33.440 --> 0:05:35.719 can still tell stories about these objects even if we 0:05:35.760 --> 0:05:38.719 don't quite understand what they are. But it's very fun 0:05:38.760 --> 0:05:41.240 and very fruitful to dig into these questions and try 0:05:41.320 --> 0:05:44.720 to understand exactly what it is we are talking about. Yeah, 0:05:44.720 --> 0:05:47.440 there are still very basic things about the universe we 0:05:47.640 --> 0:05:51.359 don't understand. And they don't just relate to tiny, little 0:05:51.520 --> 0:05:54.279 miniscule particles that you can't see. It also applies to 0:05:54.320 --> 0:05:56.680 you and me and what you do every day, which 0:05:56.760 --> 0:05:59.440 is to move or to not move, and to just 0:05:59.520 --> 0:06:03.000 sitting your chair all day long. They described physicists or 0:06:03.040 --> 0:06:07.599 cartoonists or both. I was just being general. I don't 0:06:07.600 --> 0:06:10.440 know why you're particular responding. You know, well, why are 0:06:10.440 --> 0:06:13.280 you mentioning in it? Well, it's this sort of mysterious process. Right. 0:06:13.600 --> 0:06:15.720 You sit in your chair, and you stay sitting in 0:06:15.760 --> 0:06:18.640 your chair. You expect that, unless you're getting up to 0:06:18.720 --> 0:06:21.320 move across the room or go fetch another banana, you're 0:06:21.360 --> 0:06:23.640 going to be in your chair all day long. And 0:06:23.680 --> 0:06:25.800 that's the kind of thing that seems obvious to you, 0:06:25.839 --> 0:06:28.520 And it seems obvious to Aristotle, and it seems obvious 0:06:28.560 --> 0:06:31.680 to everybody but understanding the mechanics have feel like why 0:06:31.800 --> 0:06:34.920 things at rest stay at rest, why things in motion 0:06:35.360 --> 0:06:39.400 stay in motion? Raisism really fascinating issues about like what 0:06:39.640 --> 0:06:43.080 is momentum? What is inertia? What is mass? Anyway, so 0:06:43.200 --> 0:06:50.560 today on the podcast, we'll be tackling the question what 0:06:50.880 --> 0:06:56.800 is quantized inertia? Guessing this means quantum mechanics of inertia. 0:06:57.160 --> 0:07:01.560 It's too buzzwords stuck together to make a buzzword, Sam, 0:07:01.600 --> 0:07:04.040 I'm not sure inertia is a buzzword. The people use 0:07:04.080 --> 0:07:08.039 it to denote, you know, exciting things, not usually Yeah, 0:07:08.040 --> 0:07:10.400 inertia is never a good thing. Is it like Silicon 0:07:10.480 --> 0:07:14.360 Valley disruptors. They're usually looking to disrupt industries that have 0:07:14.480 --> 0:07:18.160 too much inertia? Yes, it's something you want to break, 0:07:18.200 --> 0:07:22.000 I guess unless you're a controonism, which case you enjoy 0:07:22.000 --> 0:07:24.120 a little bit of inertia sometimes. But it is a 0:07:24.160 --> 0:07:27.080 fascinating question because I feel like inertia is a word 0:07:27.160 --> 0:07:29.720 that you know, even as a little kid, you learned 0:07:29.720 --> 0:07:33.240 pretty early on that it's just like what heavy things 0:07:33.320 --> 0:07:36.240 have that makes them hard to move. And so to 0:07:36.320 --> 0:07:38.320 think about the idea that we don't know what it 0:07:38.400 --> 0:07:41.280 is is kind of crazy. M. It's interesting word also 0:07:41.320 --> 0:07:44.120 because I'm not sure if it comes from physics and 0:07:44.160 --> 0:07:46.840 then we use it in our lives to describe, like 0:07:47.000 --> 0:07:51.160 our emotional states or our motivation levels as a metaphor 0:07:51.200 --> 0:07:53.680 for a concept from physics, or if when the other 0:07:53.720 --> 0:07:57.000 direction and physics stole it from English because it's similar 0:07:57.040 --> 0:08:00.360 to the concept that already existed. M. There's no history 0:08:00.400 --> 0:08:02.520 of words and physics. Oh, I'm sure there is, but 0:08:02.600 --> 0:08:05.480 I'm not an expert in linguistics. Somebody out there who 0:08:05.520 --> 0:08:08.160 knows the history of the word inertia right in and 0:08:08.240 --> 0:08:11.400 let us know. Well, Also, it depends what you call scientists, 0:08:11.480 --> 0:08:14.560 right maybe like early caveman saw big rock and they 0:08:14.560 --> 0:08:17.520 found it hard to move, and they said, you know, 0:08:17.680 --> 0:08:19.480 came up with a word for it. And that's kind 0:08:19.480 --> 0:08:22.040 of like being a scientist, right. That's certainly being descriptive. 0:08:22.360 --> 0:08:25.080 I think philosophers of science might quibble about whether you're 0:08:25.080 --> 0:08:28.200 doing science just by describing your experience in the world. 0:08:28.360 --> 0:08:31.440 I think maybe science also requires developing a model to 0:08:31.560 --> 0:08:35.080 explain what you've seen, what you've experienced that also predicts 0:08:35.120 --> 0:08:38.200 what would happen in the future. I'm sure they predicted 0:08:38.280 --> 0:08:41.640 that the rock wouldn't move. Rock was heavy yesterday, Rock 0:08:41.720 --> 0:08:47.280 heavy today, rock heavy tomorrow. Me scientists me published first 0:08:47.280 --> 0:08:52.200 paper or first rock. Yeah, first don't tablet. First case 0:08:52.200 --> 0:08:55.840 painting got a publication range of one impact factor one. 0:08:56.200 --> 0:08:58.440 But it is a pretty amazing question to ask, because 0:08:58.520 --> 0:09:00.960 I imagine it's not a question people ask every day, 0:09:01.000 --> 0:09:02.680 like what is inertia? We just kind of take it 0:09:02.720 --> 0:09:06.840 for granted that inertia exists. We do take it for granted, 0:09:07.080 --> 0:09:10.560 especially because we have fairly solid theories of physics which 0:09:10.800 --> 0:09:14.280 use it, you know, Newtonian physics, Einsteinian relativity. They all 0:09:14.320 --> 0:09:17.240 rely in this concept of mass and on inertia, so 0:09:17.280 --> 0:09:20.440 they play a role in the mathematical stories these theories tell, 0:09:20.800 --> 0:09:23.719 but that doesn't mean that they necessarily explain what it 0:09:23.880 --> 0:09:26.960 is or where it comes from. You know, Einstein's relativity 0:09:27.000 --> 0:09:30.000 can tell us that things with energy in them have mass, 0:09:30.040 --> 0:09:33.120 and that mass has inertia, but doesn't answer the question 0:09:33.520 --> 0:09:36.800 why why do things with energy in them tend to 0:09:36.960 --> 0:09:39.880 need a force to accelerate them? For example. Yeah, it's 0:09:39.880 --> 0:09:41.920 a pretty fascinated question, and so, as usual, we were 0:09:41.920 --> 0:09:44.040 wondering how many people out there had thought about this 0:09:44.120 --> 0:09:47.880 question or had heard of the term quantized inertia. So 0:09:47.920 --> 0:09:50.840 the things very much to everybody who volunteers for these 0:09:50.920 --> 0:09:53.080 to be on the mic for the podcast, We really 0:09:53.120 --> 0:09:55.880 appreciate it. If you'd like to hear your voice speculating 0:09:55.880 --> 0:09:58.760 about future topics for the podcast, please don't be shy 0:09:58.960 --> 0:10:02.080 right to us to instants at Daniel and Jorge dot com. 0:10:02.200 --> 0:10:03.760 So think about it for a second. What do you 0:10:03.800 --> 0:10:08.199 think is quantized inertia? Here's WHATULD be glad to say. First, 0:10:08.200 --> 0:10:12.600 I'm going to take a wild guess that quantized inertia 0:10:12.679 --> 0:10:16.679 is essentially as the quantized view of inertia. And secondly 0:10:17.040 --> 0:10:21.040 that you're using the same definition of inertia as I 0:10:21.160 --> 0:10:24.120 learned in school way back when I guess you would 0:10:24.200 --> 0:10:29.200 just build the quantum of inertia with the quantum of 0:10:29.280 --> 0:10:32.760 mass times the quantum of distance over the quantum of time, 0:10:33.280 --> 0:10:38.360 and quantized inertia would be inertia momentum whatever you wanna 0:10:38.400 --> 0:10:43.560 call it, measured in that unit. Quantized inertia sounds to 0:10:43.600 --> 0:10:47.320 me like it's going to be small packets of movement 0:10:48.040 --> 0:10:51.920 that can be discreetly segmented into you know, little little 0:10:51.920 --> 0:10:57.199 individual quantized bits of movement. So it's not this continuous 0:10:57.320 --> 0:10:59.840 everything stays in motion as long as it's in motion 0:11:00.040 --> 0:11:06.080 that we would expect from Newtonian physics inertia, but quantized 0:11:06.640 --> 0:11:11.280 quantized inertia. So m hmm, I don't know. I don't 0:11:11.280 --> 0:11:14.560 know what contest inertia means, but I'm guessing it's something 0:11:14.600 --> 0:11:18.240 to do with inertia that originates from something that doesn't 0:11:18.240 --> 0:11:22.240 have mass. So if you were to take a box um, 0:11:22.280 --> 0:11:24.920 an empty box, like completely empty, I mean, apart from 0:11:25.000 --> 0:11:27.600 virtual particles, I guess. But if you had an empty 0:11:27.640 --> 0:11:30.959 box um and waited, it would real less than if 0:11:30.960 --> 0:11:33.800 you took a box with photons in it, even though 0:11:33.840 --> 0:11:39.319 photons are massless according to the currently prevailing theory, um 0:11:39.360 --> 0:11:41.880 just because of the emotion, because of the momentum, that 0:11:41.960 --> 0:11:46.280 box would have inertia. So I don't know. Because photons 0:11:46.360 --> 0:11:50.880 are the quanta of the lecture magnetic fields, so maybe 0:11:50.960 --> 0:11:54.880 that's what quantized inertia means, but I'm not sure. All Right, 0:11:55.600 --> 0:11:57.400 not a lot of solid gases here. I like the 0:11:57.440 --> 0:12:01.040 person who said it's inertia but quantized. Isn't that what 0:12:01.160 --> 0:12:04.760 quantum physics is. It's physics, but quantized, that's a quantum 0:12:04.800 --> 0:12:09.199 everything is right quantum dessert dipping dots? Yeah, yeah, I 0:12:09.200 --> 0:12:11.520 think quantizing your dessert would probably help with your own 0:12:11.520 --> 0:12:14.240 inertia around your waist. I don't know. I think the 0:12:14.280 --> 0:12:16.480 smaller the pieces are, the more of them you can have. 0:12:16.800 --> 0:12:19.000 So you just end up consuming an infinite number of 0:12:19.000 --> 0:12:21.719 dipping dots. They're so small. How can they possibly add 0:12:21.760 --> 0:12:24.439 up to anything that seems physically impossible to you? You're 0:12:24.440 --> 0:12:28.600 a physicist, I can bend logic when it comes to dessert. Yeah, 0:12:29.200 --> 0:12:31.440 does make it harder to bend your body. But I 0:12:31.480 --> 0:12:34.480 did really like the answer that suggested that quantized inertia 0:12:34.840 --> 0:12:38.720 could come out of quantized distance and quantized time. Essentially, 0:12:38.800 --> 0:12:41.840 if all of reality is quantized, then everything is quantized, 0:12:41.880 --> 0:12:46.720 including inertia and dessert. Yeah. Yeah, I guess if space 0:12:46.800 --> 0:12:50.280 is quantized, and technically moving through space or not moving 0:12:50.320 --> 0:12:53.679 through space is also quantized. That's right. Either you're eating 0:12:53.679 --> 0:12:56.200 dessert or you're not, unless it's quantum mechanics, in which 0:12:56.200 --> 0:12:58.719 case maybe you're doing both at the same time. The 0:12:58.920 --> 0:13:01.080 dessert on certainty for stable. So this is a really 0:13:01.080 --> 0:13:03.880 funny topic, quantized inertia. I like it because it touches 0:13:04.040 --> 0:13:06.560 on a really core question of physics, like what is 0:13:06.640 --> 0:13:10.439 inertia and mass? Anyway? But also, let's this explore a 0:13:10.480 --> 0:13:14.760 recent hypothesis suggestion that might answer those questions. Right, And 0:13:14.840 --> 0:13:17.959 I guess, just to be clear, quantized inertia is a 0:13:18.000 --> 0:13:20.520 concept that comes from a theory that tries to explain 0:13:20.640 --> 0:13:23.080 what inertia is. Yeah, that's exactly right. It suggests that 0:13:23.080 --> 0:13:26.680 inertia comes from tiny, little quantum effects in the universe. 0:13:26.960 --> 0:13:28.880 All right, well, let's jump into it. And I guess 0:13:28.920 --> 0:13:32.200 let's start at the beginning. What physicists call inertia? How 0:13:32.240 --> 0:13:35.719 do they define it? So inertia first appears in Newton's theory, right, 0:13:35.760 --> 0:13:38.120 it tells us that things in motion will stay in 0:13:38.200 --> 0:13:41.480 motion and that things at rest will stay at rest. 0:13:42.080 --> 0:13:44.120 And in that sense, it's another way to state the 0:13:44.200 --> 0:13:48.000 conservation of momentum. You know, things that have no momentum 0:13:48.440 --> 0:13:51.280 their mass times their velocity will continue to have no 0:13:51.440 --> 0:13:54.600 momentum unless you apply a force to them, unless you 0:13:54.640 --> 0:13:58.320 accelerate them by applying a force. Things who have constant 0:13:58.400 --> 0:14:02.679 velocity constant momentum will continue to have that momentum unless again, 0:14:02.800 --> 0:14:06.080 you apply a force to change that momentum. So that's 0:14:06.080 --> 0:14:09.000 the principle of inertia. Right. It's kind of the idea 0:14:09.040 --> 0:14:12.520 that if something has velocity, it's hard to change that 0:14:12.640 --> 0:14:15.800 things velocity. Right, So that's kind of the concept. And 0:14:15.840 --> 0:14:18.000 maybe the more of it that you have, the more 0:14:18.000 --> 0:14:20.280 inertia that you have, the harder it is to change 0:14:20.320 --> 0:14:22.960 that velocity. Yeah, and that's where Newton's laws of physics 0:14:23.000 --> 0:14:25.520 come in. Right, you have a certain velocity, you need 0:14:25.560 --> 0:14:28.520 to apply a force to change that velocity. And because 0:14:28.600 --> 0:14:32.920 force is mass times acceleration, then to get a larger acceleration, 0:14:32.960 --> 0:14:36.280 you need a larger force. Because force is mass times acceleration. 0:14:36.520 --> 0:14:39.400 The more mass you have, the larger the force you 0:14:39.440 --> 0:14:42.400 need to get the same acceleration. So things that have 0:14:42.520 --> 0:14:46.400 more mass therefore need bigger forces in order to accelerate them. 0:14:46.400 --> 0:14:48.280 Like if you push on a tiny rock, you're going 0:14:48.360 --> 0:14:50.320 to accelerate it more than if you push on the 0:14:50.480 --> 0:14:53.440 entire Earth with the same force. Right, So then I 0:14:53.440 --> 0:14:57.040 guess is inertia related to mass? Does it include mass 0:14:57.120 --> 0:14:59.880 or is it just the general concept that you need 0:15:00.040 --> 0:15:02.080 to force to move a mass? You know what I mean? 0:15:02.320 --> 0:15:04.120 The mass that we're talking about there we often call 0:15:04.240 --> 0:15:07.720 inertial mass because we think it's the mass that gives 0:15:07.760 --> 0:15:10.960 things inertia the property of having mass. If you didn't 0:15:11.000 --> 0:15:13.040 have mass, then you wouldn't have inertia. So if the 0:15:13.040 --> 0:15:16.360 inertia comes from having mass, because you also need that 0:15:16.480 --> 0:15:19.360 mass to have momentum. Right, Although could you also say 0:15:19.400 --> 0:15:22.200 that you can't have mass if you don't have inertia, 0:15:22.600 --> 0:15:26.040 or that what we call mass is actually the property 0:15:26.080 --> 0:15:28.160 of inertia. I think it's the second that what we 0:15:28.280 --> 0:15:31.000 call mass is actually the property of inertia. That's why 0:15:31.040 --> 0:15:33.960 we get more specific and we call it inertial mass, right, 0:15:34.000 --> 0:15:36.960 because there are other kinds of masses. There are other 0:15:37.080 --> 0:15:40.160 kinds of masses exactly. It's also a subtle distinction between 0:15:40.200 --> 0:15:44.000 momentum and inertia because it is possible to have momentum 0:15:44.000 --> 0:15:47.800 without mass, Like photons have momentum even though they don't 0:15:47.840 --> 0:15:51.480 have any mass. Does that mean photons have inertia or not? 0:15:51.840 --> 0:15:55.240 Or is it all very light? Well, photons do carry momentum, right, 0:15:55.280 --> 0:15:58.280 And so a photon, for example, can bounce off of 0:15:58.360 --> 0:16:01.120 something and push it, you know, like a solar sale 0:16:01.240 --> 0:16:05.119 is a photon pushing on something and transferring its momentum 0:16:05.200 --> 0:16:08.600 to that object. So messence to have momentum, but inertia 0:16:09.080 --> 0:16:12.400 is like the resistance of an object of changing its velocity, 0:16:12.520 --> 0:16:16.320 and photons can't change their velocity, right, they always travel 0:16:16.360 --> 0:16:18.840 at the speed of light. So inertia when it comes 0:16:18.880 --> 0:16:21.800 to photons is very confusing. Does that mean photons have 0:16:21.920 --> 0:16:24.840 infinite inertia? That's an interesting question. You can change the 0:16:24.920 --> 0:16:28.160 direction of a photon even though you can change its velocity, 0:16:28.240 --> 0:16:31.000 and that does actually count as a change in its 0:16:31.120 --> 0:16:35.120 velocity vector because you're changing its components. Something with infinite 0:16:35.120 --> 0:16:37.880 inertia you wouldn't be able to change its direction either. 0:16:38.680 --> 0:16:41.160 So light is a sort of special category there. M 0:16:41.480 --> 0:16:43.400 I think you're saying that like does have inertia, or 0:16:43.440 --> 0:16:46.800 maybe that it doesn't apply to things without inertial mass. 0:16:46.840 --> 0:16:49.320 I think there's a few different concepts here. There's momentum, 0:16:49.360 --> 0:16:52.680 which light definitely carries, but inertia here we're talking about 0:16:52.720 --> 0:16:56.400 inertial mass, and photons definitely don't have any inertial mass. 0:16:57.480 --> 0:17:00.080 All right, So some particles in the universe seemed to 0:17:00.200 --> 0:17:04.040 have inertial mass, and it's sort of related to ecelind 0:17:04.119 --> 0:17:07.200 theories about gravity too, right, that's right, And there's another 0:17:07.280 --> 0:17:10.000 interesting wrinkle about inertial mass there, which is it doesn't 0:17:10.119 --> 0:17:12.520 just come from the mass of your particles, right. So 0:17:12.600 --> 0:17:15.320 for example, particles have their own little mass which they 0:17:15.320 --> 0:17:17.440 get from the Higgs boson. But then you can put 0:17:17.480 --> 0:17:19.840 them together and use energy to build those bonds, and 0:17:19.840 --> 0:17:23.159 that energy also contributes to the mass of the object. So, 0:17:23.240 --> 0:17:25.920 for example, a proton is made of little quirks. Those 0:17:25.960 --> 0:17:29.720 corks have really really tiny inertial masses. The proton has 0:17:29.760 --> 0:17:32.680 a lot of inertial mass because of the energy in it. 0:17:32.760 --> 0:17:35.000 So the proton, this bound state of all the corks, 0:17:35.200 --> 0:17:37.800 has a lot more mass than the things it's made 0:17:37.800 --> 0:17:40.600 out of. And that's because energy inside an object is 0:17:40.600 --> 0:17:43.600 sort of what gives it mass, it gives it inertia. 0:17:43.720 --> 0:17:46.159 So there's all these different ideas here. What is mass? 0:17:46.200 --> 0:17:49.040 What is inertia for an object? It reflects how much 0:17:49.160 --> 0:17:53.040 energy is sort of stored inside the object, not just 0:17:53.160 --> 0:17:55.880 the mass of the objects inside of it. Right, And 0:17:55.960 --> 0:17:58.280 in our book frequently ask questions about the unerse We 0:17:58.400 --> 0:18:01.160 tackled this in a whole chat there where we basically 0:18:01.160 --> 0:18:03.520 conclude that there's no such thing as mass, right, like 0:18:03.640 --> 0:18:06.320 everything is just energy because most of what we call 0:18:06.400 --> 0:18:09.359 mass in our bodies is actually the energy stored in 0:18:09.400 --> 0:18:12.400 the between the particles. And also like even the mass 0:18:12.480 --> 0:18:14.880 of a particle is really just the energy it has 0:18:14.920 --> 0:18:18.119 with the Higgs field, right, and so it's all just energy, 0:18:18.880 --> 0:18:21.840 which means there is such a thing mass. It is 0:18:21.880 --> 0:18:24.440 all just energy, but it does seem to have inertia, 0:18:24.600 --> 0:18:28.000 and that's too. Also in other counterintuitive examples, like with photons. 0:18:28.320 --> 0:18:30.520 Photons have no mass, but if you put a bunch 0:18:30.520 --> 0:18:33.359 of photons in a box with mirrors inside, for example, 0:18:33.400 --> 0:18:36.639 so they're bouncing around, then that will have more mass 0:18:36.680 --> 0:18:39.359 than an empty box. So you can like make a 0:18:39.440 --> 0:18:42.359 box more massive by shooting a laser into it and 0:18:42.440 --> 0:18:45.520 capturing those photons because you put energy into it. So 0:18:45.600 --> 0:18:47.720 it is all just energy, but that energy has this 0:18:47.880 --> 0:18:51.240 property of inertia. Right. It's kind of seems like, um, 0:18:51.359 --> 0:18:54.520 maybe the right order of these concepts is that you know, 0:18:54.560 --> 0:18:58.480 whenever you have energy localized or put together in a 0:18:58.520 --> 0:19:02.080 particular object or spa or even a box, it's somehow 0:19:02.160 --> 0:19:06.120 difficult to move that box or object, like you need 0:19:06.160 --> 0:19:10.040 to apply some kind of energy to change its velocity. 0:19:10.400 --> 0:19:13.919 And then that's the concept of inertia. And then what 0:19:13.960 --> 0:19:17.680 we call mass is kind of a measure of its inertia. Yeah, 0:19:17.960 --> 0:19:20.560 mass is like a dial that tells you how much 0:19:20.600 --> 0:19:23.119 stored energy there is inside of it, And there's this 0:19:23.160 --> 0:19:25.560 relationship between the stored energy inside of it and how 0:19:25.600 --> 0:19:28.159 hard it is to move that thing. And mass is 0:19:28.200 --> 0:19:31.520 that multiplicative factor between those two things, exactly right, which 0:19:31.520 --> 0:19:34.520 means inertia? Is it kind of like predates mass or 0:19:34.600 --> 0:19:37.960 is more important or you know, it comes before the 0:19:38.000 --> 0:19:41.080 concept of mass, So it's pretty pretty important, right before 0:19:41.119 --> 0:19:44.680 in what sense, like chronologically or conceptually, I mean like conceptually, 0:19:44.680 --> 0:19:46.840 like in terms of the way that we think about 0:19:46.880 --> 0:19:50.080 these ideas, the order of concepts, it comes first, right, Yeah, 0:19:50.080 --> 0:19:51.840 you can definitely think about it that way. What we 0:19:51.880 --> 0:19:54.600 observe is that there are things in the universe and 0:19:54.640 --> 0:19:57.880 those things seem to have inertia. We explain that by 0:19:57.920 --> 0:20:00.680 coming up with this concept of mass for these things. 0:20:01.119 --> 0:20:03.600 That is sort of the origin of their inertia. But 0:20:03.640 --> 0:20:06.399 it's really just more of a description than an actual explanation. 0:20:06.440 --> 0:20:10.240 We don't really understand the mechanism by which energy resists 0:20:10.560 --> 0:20:13.640 changes in its inertia. I think that's what you mean. Well, 0:20:13.680 --> 0:20:15.679 I think I mean, like in your light box. Example, 0:20:15.720 --> 0:20:18.200 if I put light inside of a box with mirrors 0:20:18.240 --> 0:20:20.679 inside of it, it's going to have inertia, But that 0:20:20.720 --> 0:20:23.080 doesn't mean that the light it put into it has mass. 0:20:23.119 --> 0:20:25.320 So it's almost like inerish is kind of a more 0:20:25.359 --> 0:20:29.679 important or overarching, kind of fundamental concept than mass. I 0:20:29.680 --> 0:20:31.760 think big inertia will be happy to hear you say that. 0:20:31.920 --> 0:20:36.120 Oh good, wait for the check. All right, Well, let's 0:20:36.160 --> 0:20:39.840 get into this idea of anerition, why we don't understand 0:20:39.920 --> 0:20:43.080 what it is, and also a new theory that might 0:20:43.240 --> 0:20:45.840 have an answer for it. First, let's take a quick break. 0:20:58.440 --> 0:21:02.560 All right, we're talking about nourish and um. Ironically, it's 0:21:02.600 --> 0:21:04.159 taken as a well to get to this topic. You 0:21:04.240 --> 0:21:06.200 might say, we have a lot of inertia, and there's 0:21:06.200 --> 0:21:09.120 also some sort of inertia in the field about answering 0:21:09.160 --> 0:21:12.000 these questions at the foundations. Once we have a theory 0:21:12.040 --> 0:21:14.359 that works that we can use to describe the universe, 0:21:14.359 --> 0:21:15.879 a lot of people like to just run with it 0:21:16.080 --> 0:21:18.480 and go off and predict things and build ideas on 0:21:18.560 --> 0:21:20.800 top of it. There isn't always an appetite for like 0:21:20.960 --> 0:21:23.920 digging into the details of like what does this mean? 0:21:24.520 --> 0:21:27.000 It feels to people a little bit like doing philosophy, 0:21:27.040 --> 0:21:29.520 which is why for a long time people ignore questions 0:21:29.560 --> 0:21:31.359 at the heart of like quantum mechanics, you know, what 0:21:31.520 --> 0:21:34.240 our particles and is the way of function actually collapsing? 0:21:34.560 --> 0:21:36.680 Because we had the theory that worked. But I think 0:21:36.680 --> 0:21:39.080