WEBVTT - What is the Weak Force? 0:00:08.520 --> 0:00:12.000 Hey, hey, you have strong opinions about naming things, didn't you. 0:00:12.480 --> 0:00:16.040 I just don't like kids when things are named in 0:00:16.079 --> 0:00:19.239 a very confusing way, or where the name actually confuses 0:00:19.280 --> 0:00:22.120 you instead of making things clear. All right, Well, then 0:00:22.160 --> 0:00:24.560 I have a bit of a personal question. How did 0:00:24.600 --> 0:00:27.800 you pick the names of your kids? Not through physics, 0:00:27.840 --> 0:00:32.640 for sure, that's definitely did not. There's not one called strange, 0:00:32.680 --> 0:00:37.360 one called charm. They're both strange and charming, for sure. 0:00:38.440 --> 0:00:42.280 That's a linear superposition. There is physics there. They are 0:00:42.920 --> 0:00:48.120 definitely quantum and delete for sure. Our son was named 0:00:48.159 --> 0:00:51.000 my wife had had a dream, and that's how she 0:00:51.080 --> 0:00:53.239 came up with the name for our son. She just 0:00:53.720 --> 0:00:55.760 came up with the name in the dream. And my 0:00:55.880 --> 0:00:59.320 daughter is named after a Jane Austen character. Wow. Alright, 0:00:59.360 --> 0:01:03.480 so both bired by mental realms outside of the physical world. 0:01:19.760 --> 0:01:23.440 I am more handmake cartoonists and the creator of PhD comics. 0:01:23.600 --> 0:01:26.600 I'm Daniel. I'm a particle physicist, and I'm a connoisseur 0:01:26.680 --> 0:01:30.280 of all jokes physicals ee, strong electric and even weak 0:01:30.319 --> 0:01:34.720 ones and banana forces. Of course, that's right, And of 0:01:34.760 --> 0:01:37.800 course the mysterious banana field that feels the universe and 0:01:37.840 --> 0:01:40.720 it is mostly concentrated around Jorge's head, and together we 0:01:40.840 --> 0:01:44.840 are co authors on books and other projects. But this 0:01:44.920 --> 0:01:48.160 is our podcast, Daniel and Jorge Explained the Universe, a 0:01:48.280 --> 0:01:50.600 production of I Heart Radio, in which we take you 0:01:50.640 --> 0:01:53.600 on a tour of all the weird, crazy, amazing stuff 0:01:53.640 --> 0:01:55.360 in the universe and try to explain it to you. 0:01:55.480 --> 0:01:58.360 So you go away going, wow, that's kind of cool. 0:01:58.400 --> 0:02:02.280 I never understood that before. All these strong and amazing 0:02:02.320 --> 0:02:05.120 things and even the weak but significant things in the 0:02:05.200 --> 0:02:07.960 universe that maybe every once you know about. That's right. 0:02:08.200 --> 0:02:11.800 It's a forceful exposition of all the fascinating things about 0:02:11.840 --> 0:02:14.720 the universe. Oh man, now you're just forcing it. I 0:02:14.760 --> 0:02:19.200 think that's right. Well, you know, my my joke, force 0:02:19.280 --> 0:02:22.480 is pretty weak. But forces themselves are sort of a 0:02:22.520 --> 0:02:26.000 weird thing. It's like, forces are something that physicists you've 0:02:26.080 --> 0:02:29.800 even had a hard time grappling with over the centuries. Well, 0:02:29.800 --> 0:02:32.360 it's something that's really intuitive. I think. You know, as 0:02:32.400 --> 0:02:34.160 a little kid, even as a baby, you sort of 0:02:34.200 --> 0:02:37.560 get the idea of force, right, Thanks pushing you, thanks 0:02:37.560 --> 0:02:40.840 pulling you, gravity, pushing you down. Yeah, but I think 0:02:40.880 --> 0:02:43.520 your intuition is misleading. I think most people think of 0:02:43.520 --> 0:02:45.920 a force as something as a push, right, something that's 0:02:46.160 --> 0:02:48.720 touching you. Somebody comes up to you, pushes you over, 0:02:48.960 --> 0:02:51.359 you fall over, you move your role or whatever. So 0:02:51.400 --> 0:02:54.360 I think most people think of forces as touching. The 0:02:54.440 --> 0:02:57.040 really weird thing about forces is when they can act 0:02:57.120 --> 0:02:59.560 without touching, right, When they can, like when you see 0:02:59.560 --> 0:03:03.600 a mad levitating, it seems almost like magic, right, because 0:03:03.639 --> 0:03:06.079 this this, these two things are acting on each other 0:03:06.120 --> 0:03:09.680 without actually touching each other. Yeah, it's weird. And so 0:03:09.760 --> 0:03:13.680 today we'll be talking about one particular force out of 0:03:14.120 --> 0:03:16.560 all the forces out there in the universe, one that 0:03:16.760 --> 0:03:20.840 is maybe not the strongest one, but that led to 0:03:20.919 --> 0:03:23.440 some amazing discoveries. Right, that's right. It's not the most 0:03:23.440 --> 0:03:26.320 powerful force, but it did give us some amazing hints 0:03:26.360 --> 0:03:29.320 into the way the universe works. So it's weekly powered, 0:03:29.360 --> 0:03:32.400 but plays a strong role in the sort of overarching 0:03:32.480 --> 0:03:36.160 drama that is physics. Yep, it's a four sets inside everyone, right, 0:03:36.520 --> 0:03:38.880 it's inside of me, inside of you, inside of everyone 0:03:38.960 --> 0:03:42.200 listening to this podcast. That's right. It's everywhere in the universe, 0:03:42.200 --> 0:03:44.280 and it plays an important role in how we live 0:03:44.320 --> 0:03:47.080 and how we die and how we power ourselves. So 0:03:47.160 --> 0:03:54.440 to be on the podcast, we'll be talking about the 0:03:54.480 --> 0:03:59.320 weak fours? Weak fours? Are you just trying to add 0:03:59.360 --> 0:04:02.800 some drama to it because it needs some panash? It 0:04:02.880 --> 0:04:05.400 was a little anti climatic. Did you say I thought 0:04:05.400 --> 0:04:08.760 you might go with weak nuclear force because nuclear gives 0:04:08.760 --> 0:04:11.680 it some sort of like edge of mysteriousness. Right, the 0:04:11.720 --> 0:04:16.720 weak quantum? No of the week? Black holes pilate on. 0:04:17.360 --> 0:04:22.400 Let's just give him multiple hyvingated names the week, true, Guadalajara, 0:04:23.120 --> 0:04:28.000 Montre exactly. Um, that would be a lot more fun. No, 0:04:28.160 --> 0:04:30.840 the weak force is really amazing, it's fascinating. Yeah, it's 0:04:30.839 --> 0:04:35.240 one of the four fundamental forces in nature. Right, there's 0:04:35.279 --> 0:04:37.840 only four of them? Yeah, well, spoiler alert turns out 0:04:37.839 --> 0:04:44.919 there's three. You eliminated one like Pluto just got deep declassified. No. No, 0:04:45.080 --> 0:04:47.560 that's the goal of physics, right, is to not have 0:04:47.600 --> 0:04:50.320 four forces. We don't want to say, hey, here's how 0:04:50.360 --> 0:04:53.440 the universe works. There are four totally weird, separate rules 0:04:53.480 --> 0:04:55.480 about things, how things can push and pulling each other. 0:04:55.920 --> 0:04:59.000 We we think, we hope, we want to explain the 0:04:59.040 --> 0:05:01.880 universe in terms of one force. So the story of 0:05:01.920 --> 0:05:04.880 physics so far is look around you see all the 0:05:04.920 --> 0:05:07.200 weird thing that's happening in the universe and try to 0:05:07.200 --> 0:05:09.880 describe them all in terms of the smallest number of things, 0:05:09.960 --> 0:05:12.599 the smallest number of forces. So yeah, the goal is 0:05:12.640 --> 0:05:14.760 to sort of take things off the list and describe 0:05:14.800 --> 0:05:17.560 everything in terms of just one thing. So you're saying, 0:05:17.600 --> 0:05:20.000 there used to be only four forces in the universe, 0:05:20.560 --> 0:05:24.560 and then phasics killed one of them and or married 0:05:24.560 --> 0:05:27.240 two of them, and now there are only three fundamental 0:05:27.279 --> 0:05:30.560 forces in the universe. Yeah, well, this the drama is 0:05:30.560 --> 0:05:33.920 even more because we suspect that in the first few 0:05:33.920 --> 0:05:36.599 moments after the Big Bang there was just one force, 0:05:37.080 --> 0:05:39.320 but then as the universe cooled, we think they've broke 0:05:39.440 --> 0:05:42.200 up into all these different forces. And what we're trying 0:05:42.200 --> 0:05:44.960 to do now is sort of re run that backwards 0:05:44.960 --> 0:05:47.360 and understand, like, can we bring these things together. Can 0:05:47.360 --> 0:05:50.080 we understand these things in terms of one big picture? 0:05:50.839 --> 0:05:53.039 How do we bring marry these things back together? You know, 0:05:53.080 --> 0:05:56.160 it's like a it's like a universal divorce early on, 0:05:56.560 --> 0:05:58.680 and we're trying to bring the couples back together and 0:05:58.720 --> 0:06:00.800 show them how they can work together. You're trying to 0:06:00.800 --> 0:06:04.159 bring the band back together. Basically, it's like the Beatles 0:06:04.160 --> 0:06:07.280 broke up, and you know, we enjoyed their individual work. 0:06:07.360 --> 0:06:11.440 But come on, guys, yeah, that's a great analogy. Wouldn't 0:06:11.480 --> 0:06:13.360 you like to just describe the Beatles instead of having 0:06:13.400 --> 0:06:16.320 to describe all four members of the Beatles? Right, That's 0:06:16.320 --> 0:06:18.479 exactly what we're trying to do. We're trying to show 0:06:18.520 --> 0:06:20.480 you that, you know, the drums are not interesting on 0:06:20.520 --> 0:06:22.840 their own, They're just part of a larger harmony. Right. 0:06:22.839 --> 0:06:24.800 They make much more sense when you understand them in 0:06:24.920 --> 0:06:27.719 terms of the guitar parts and the vocals which come 0:06:27.800 --> 0:06:31.520 together to make this amazing beautiful music. Right. Yeah, the 0:06:31.560 --> 0:06:35.080 physics of the Beatles, that will be the next exactly. 0:06:35.120 --> 0:06:36.960 So today we're gonna show you how Paul and John 0:06:36.960 --> 0:06:42.720 were actually the same person. Spoiler alert, they were the 0:06:42.760 --> 0:06:46.520 same person. That's right. And ringoes an alien. Everybody knows 0:06:46.600 --> 0:06:50.800 ringos an alien, right, all right? So the week nuclear 0:06:50.839 --> 0:06:54.240 force and so that's uh, it's not the most popular force. 0:06:54.400 --> 0:06:59.400 You know, most people know electromagnetism and gravity. Right. It 0:06:59.480 --> 0:07:04.320 is part of the forces, isn't it. Yeah, maybe it is. 0:07:04.360 --> 0:07:07.080 Maybe it's the ringo of forces. It's sort of overlooked, 0:07:07.360 --> 0:07:10.240 and uh, you know, dismissed, but in the end fundamentally 0:07:10.280 --> 0:07:13.120 important to making things work. Just like Ringo, you kept 0:07:13.440 --> 0:07:16.800 going to the harmony together exactly without the beats together, 0:07:17.320 --> 0:07:19.640 he wouldn't have a good song, That's right. Who ever 0:07:19.680 --> 0:07:22.520 heard a good pop song without without without a drum line, 0:07:22.560 --> 0:07:27.080 without Ringo? All right? So we were wondering it is 0:07:27.160 --> 0:07:29.600 kind of the lesser known maybe of the forces, and 0:07:29.600 --> 0:07:31.600 so we were wondering how many people out there knew 0:07:32.680 --> 0:07:34.760 what the weak force was. Yeah, and this is one 0:07:34.760 --> 0:07:36.720 of the times when I really had no idea what 0:07:36.800 --> 0:07:39.320 to expect. Had everybody heard of the weak force and 0:07:39.320 --> 0:07:42.080 they We're going to spout off some interesting physics about it, 0:07:42.240 --> 0:07:44.360 or are they going to get a bunch of blank stairs? 0:07:44.880 --> 0:07:47.360 So I was pretty curious, and so as usual, Daniel 0:07:47.400 --> 0:07:50.480 went out into the street and as random strangers if 0:07:50.520 --> 0:07:53.040 they knew what the weak force was. And so before 0:07:53.080 --> 0:07:55.840 you listen to these answers, think a little bit yourself. 0:07:55.920 --> 0:07:59.600 If someone approached you on the street and wearing sandals 0:07:59.680 --> 0:08:03.520 and supporting a beard, if they asked you randomly what 0:08:03.640 --> 0:08:06.160 the weak force, You're given away my disguise, man, and 0:08:06.160 --> 0:08:08.160 I'm gonna have to wear a completely different disguise when 0:08:09.040 --> 0:08:12.320 they'll throw them off. They like, you can't be Daniel, 0:08:12.800 --> 0:08:14.880 I can I can't seat your toes. So if you 0:08:14.960 --> 0:08:17.360 were asked this question, you would you know the answer 0:08:17.440 --> 0:08:20.080 to it. Here's what people had to say. Yeah, has 0:08:20.200 --> 0:08:24.480 kind of governs radioactive to ka most particle stuff. I 0:08:24.480 --> 0:08:28.600 guess I'm not heard of the weak nuclear force. Have 0:08:28.680 --> 0:08:31.640 you heard of the strong nuclear force, the medium nuclear force, 0:08:32.200 --> 0:08:35.080 the super weak nuclear force? I made most of those, 0:08:35.120 --> 0:08:37.600 though we nuclear force not as well, but I've heard 0:08:37.640 --> 0:08:40.440 of it. I'm not sure. No, I've not heard of that. No, 0:08:41.120 --> 0:08:42.800 the m R I am measures in a clear force, 0:08:42.840 --> 0:08:47.360 and then you can know that's that's one of the 0:08:47.559 --> 0:08:51.360 four main types of forces in physics, not just in physics, 0:08:51.400 --> 0:08:54.040 in the universe right in the universe. Sure, it's kind 0:08:54.040 --> 0:08:56.040 of it's a kind of part to strong nuclear force. 0:08:56.320 --> 0:08:57.800 Why do we have it? What is it important? Or 0:08:57.800 --> 0:08:59.400 what does it do? Has something to do with how 0:08:59.440 --> 0:09:03.880 adams are together? I don't know exactly alright, So not 0:09:04.000 --> 0:09:05.959 a lot of yeses. I got a lot of blank 0:09:06.040 --> 0:09:08.880 looks on this one, that's for sure. Well, some people 0:09:09.400 --> 0:09:11.360 most people said no, they've never heard of it. But 0:09:11.520 --> 0:09:15.760 somebody actually said that it's related to the radioactive radio 0:09:15.760 --> 0:09:19.319 activity radioactive decay, Yeah exactly, and somebody even understood it 0:09:19.440 --> 0:09:22.520 was like connected to particle physics experiments we do in Geneva. 0:09:22.679 --> 0:09:25.760 So a hundred bonus points to that because your office 0:09:25.800 --> 0:09:30.640 made another physics professor that was me with disguising my 0:09:30.640 --> 0:09:33.920 own voice, asking myself a questions. Spoiler alert. They're all 0:09:34.000 --> 0:09:39.600 you always every episode. I'm just amazing and impressions right now, 0:09:39.679 --> 0:09:43.280 you know what one of my UM career goals is, please, 0:09:43.520 --> 0:09:46.360 speaking of which is um? Do you ever read The Onion? 0:09:46.600 --> 0:09:49.120 They have this fantastic people in the street section with 0:09:49.320 --> 0:09:52.800 ask people ridiculous questions and every week they have the 0:09:52.840 --> 0:09:55.679 same four pictures and they just give them made up 0:09:55.760 --> 0:09:59.800 names and jobs, you know, bone crusher or like you 0:10:00.120 --> 0:10:03.120 keyboard tester or something. My career goal is to get 0:10:03.200 --> 0:10:05.000 my face is used on the Onion. Is one of 0:10:05.040 --> 0:10:09.000 those people on the street saying something dumb. But I've 0:10:09.000 --> 0:10:11.840 actually written to the Onions several times volunteering, but never 0:10:11.880 --> 0:10:15.120 heard back. Please use my picture exactly, please make fun 0:10:15.200 --> 0:10:17.679 of me. Every week? Do they write back or they 0:10:17.720 --> 0:10:21.400 just ignored it? No? No, Unlike other Internet celebrities, they 0:10:21.440 --> 0:10:25.520 did not respond to my cold call. We'll keep trying, Daniel, 0:10:25.800 --> 0:10:29.199 there's always hope, all right, I will. So, yeah, somebody, 0:10:29.559 --> 0:10:32.079 most people didn't know what it was, and so it 0:10:32.480 --> 0:10:34.600 would Did that surprised you. I mean, it's not something 0:10:34.640 --> 0:10:38.320 that is usually covered in you know, high school physics. 0:10:38.320 --> 0:10:41.240 Even it didn't surprise me because it is a bit esoteric. 0:10:41.360 --> 0:10:44.320 And also it's not something people experience. You know, people 0:10:44.480 --> 0:10:46.760 experience gravity, they all know what it is. They have 0:10:46.840 --> 0:10:48.800 to understand it, they have an intuitive sense of it. 0:10:49.040 --> 0:10:53.119 People experience electricity, right, We've all been shocked by static electricity. 0:10:53.160 --> 0:10:57.360 People experience magnets, right. But people don't interact with the 0:10:57.360 --> 0:10:59.600 weak nuclear force very much. You don't really see its 0:10:59.640 --> 0:11:02.880 conto quince is directly. You can't tell the difference between 0:11:02.880 --> 0:11:04.320 it and something else the way you can tell the 0:11:04.320 --> 0:11:08.559 difference between gravity and magnetism. Right. Yeah, Well, there's very 0:11:08.720 --> 0:11:10.520 a couple of things about it. First of all, it's 0:11:10.559 --> 0:11:15.079 a force, and second it's weak. That's right, It's really 0:11:15.120 --> 0:11:19.439 really weak, like compared to electromagnetism and the strong nuclear force, 0:11:19.800 --> 0:11:22.559 it just is not very effective. And and one way 0:11:22.559 --> 0:11:26.000 to understand that is to think about how particles interact, right, 0:11:26.040 --> 0:11:29.600 like when you touch something or when you bounce against something, 0:11:29.880 --> 0:11:32.719 that's all done with particles. That's particles pushing against each 0:11:32.720 --> 0:11:35.240 other or interacting with each other. I mean, the particles 0:11:35.240 --> 0:11:37.960 in my finger are interacting with the particles in the 0:11:38.040 --> 0:11:40.360 table and so that and they're pushing against each other, 0:11:40.679 --> 0:11:43.920 that's right. And that's mostly using electromagnetism because it has 0:11:43.960 --> 0:11:46.320 to do with the bonds and the electrons holding the 0:11:46.360 --> 0:11:49.360 atoms tightly together and making this like you know, chain 0:11:49.400 --> 0:11:52.880 link fence of atoms that your finger can't pass through. 0:11:53.400 --> 0:11:56.000 But there are other particles, right, And that's because all 0:11:56.000 --> 0:11:57.559 the particles in your finger and all the particles in 0:11:57.559 --> 0:12:00.920 the table feel electromagnetism, but they're our particles that don't 0:12:00.960 --> 0:12:05.320 feel electromagnetism, like this mysterious particle called the neutrino. The 0:12:05.360 --> 0:12:09.200 neutrino doesn't feel electromagnetism, and it doesn't feel a strong force, 0:12:09.760 --> 0:12:12.240 and it has almost no mass or it hardly feels 0:12:12.240 --> 0:12:14.959 any gravity. The only way it interacts is through the 0:12:15.000 --> 0:12:17.000 weak force, and so it's a good lens for figuring 0:12:17.040 --> 0:12:20.080 out like how weak is the weak force? Yeah, we 0:12:20.120 --> 0:12:23.840 had a whole podcast episode about neutrinos. And we sort 0:12:23.840 --> 0:12:27.079 of talked about how, you know, the forces are sort 0:12:27.120 --> 0:12:30.200 of like social media channels. You know, there's Twitter, there's Facebook, 0:12:30.720 --> 0:12:32.960 there's Instagram that you can interact with people, but some 0:12:33.040 --> 0:12:36.600 people don't use some of the don't use Instagram, where 0:12:36.640 --> 0:12:38.840 they only use Twitter, or they only or they or 0:12:38.840 --> 0:12:41.120 they use all three. And neutrinos are like that, they 0:12:41.200 --> 0:12:45.160 only subscribe to this one very lightly used social media 0:12:45.240 --> 0:12:47.199 channel and so they hardly interact with the friends that 0:12:47.600 --> 0:12:51.320 it's the friends store of media channel, the original And 0:12:51.360 --> 0:12:54.000 so that's why neutrino can pass right through you, and 0:12:54.080 --> 0:12:56.760 a neutrino can pass right through the Earth right. We 0:12:56.840 --> 0:12:59.600 do these experiments where we look at neutrinos from the 0:12:59.640 --> 0:13:02.920 Sun and we use the entire Earth as an instrument 0:13:03.040 --> 0:13:05.200 to try to get the neutrinos to interact, but most 0:13:05.200 --> 0:13:07.920 of them fly right through the entire Earth without interacting. 0:13:08.800 --> 0:13:10.680 And if you had to say, like how thick a 0:13:10.720 --> 0:13:14.280 wall would I have to build to block neutrinos, Well, 0:13:14.360 --> 0:13:17.760 neutrinos can fly through a light year of lead and 0:13:17.800 --> 0:13:21.360 have a fifty percent chance I'm getting through. So I 0:13:21.400 --> 0:13:23.640 mean it's it's hard to even fathom, like how big 0:13:23.640 --> 0:13:26.560 a wall you would have to build to effectively block neutrinos. 0:13:26.600 --> 0:13:29.120 And the reason is that the weak force is so 0:13:29.200 --> 0:13:33.000 weak that every time the neutrino near something, it rolls 0:13:33.000 --> 0:13:35.160 a die and the dye has to come up just 0:13:35.360 --> 0:13:37.560 right for it to interact. Most of the time it 0:13:37.640 --> 0:13:41.800 just ignores it. Oh wait, so all right, so we're 0:13:41.800 --> 0:13:43.959 getting into what is the weak force, and you're saying 0:13:43.960 --> 0:13:46.720 that it is super weak, and you're saying that it's weak, 0:13:46.800 --> 0:13:49.880 not because it's just the weak force, but it's it's 0:13:49.920 --> 0:13:53.520 just less likely to interact with you. That's exactly what 0:13:53.559 --> 0:13:56.560 weak means, right, that it has a smaller chance to interact. 0:13:57.120 --> 0:13:59.800 Right that you shoot these two things against each other 0:13:59.840 --> 0:14:02.240 and will less often have an interaction. But when they 0:14:02.280 --> 0:14:04.920 do interact, the force that you actually feel is also 0:14:05.000 --> 0:14:07.079 weak or not. Oh, I see what you mean. No, 0:14:07.200 --> 0:14:10.040 the magnitude of the force is not effected. It's how 0:14:10.080 --> 0:14:13.079 often it happens. It's how likely it is to happen 0:14:13.200 --> 0:14:16.400 when it interacts with the nucleus. For example, it bounces 0:14:16.400 --> 0:14:18.160 off and goes in the other direction. It's not like 0:14:18.440 --> 0:14:21.520 just slightly deflected. It's just that it doesn't happen very often. 0:14:21.520 --> 0:14:24.360 It passes right through most of the nuclei without doing 0:14:24.400 --> 0:14:27.760 anything and just ignores the last. But in terms of magnitude, 0:14:27.760 --> 0:14:30.440 like when it does interact, it is as strong as 0:14:30.480 --> 0:14:32.560 the other forces. Yeah, that's a really good question. I 0:14:32.680 --> 0:14:34.440 never really thought about it that way. It's just a 0:14:34.520 --> 0:14:37.600 question of whether it interacts. The strength of the force 0:14:37.640 --> 0:14:41.640 reheally determines whether it's interacting, and so for example, you know, 0:14:41.680 --> 0:14:44.320 the strong force is really really strong. There's a lot 0:14:44.320 --> 0:14:47.000 of energy in that interaction, and so it's going to 0:14:47.080 --> 0:14:51.160 interact with everything else that feels it. Electromagnetism is a 0:14:51.200 --> 0:14:54.320 powerful force, and that means that it's going to interact 0:14:54.360 --> 0:14:56.560 almost all the time, and so you get lots of 0:14:56.600 --> 0:14:58.720 particles contributing. But if you're like going to measure it 0:14:58.840 --> 0:15:01.360 per particle, I think I think it's just another way 0:15:01.360 --> 0:15:04.200 of saying the same thing. I think. Um, you know, 0:15:04.200 --> 0:15:06.120 the strength of the force between them is another way 0:15:06.120 --> 0:15:08.360 of saying how likely are they to interact or not 0:15:09.040 --> 0:15:12.000 the other Fascinating about the weak force. One another reason 0:15:12.040 --> 0:15:15.000 to think about why it's weak is that it doesn't 0:15:15.040 --> 0:15:19.680 interact over a very long range, like electromagnetism to electrons 0:15:19.680 --> 0:15:21.760 that are like a thousand miles away from each other, 0:15:21.960 --> 0:15:24.480 they can feel each other and they feel each other's 0:15:24.480 --> 0:15:29.360 electric fields. Right that electromagnetism extends infinitely far the weak force. 0:15:29.440 --> 0:15:31.720 Another way to think about why it's weak is that 0:15:31.760 --> 0:15:34.520 it only interacts with things very very near it, right, 0:15:34.640 --> 0:15:37.000 Like you have to be really close to the neutrino 0:15:37.160 --> 0:15:40.120 to interact with it. Is that true? Like to electrons, 0:15:40.280 --> 0:15:43.560 even though even if there are millions of light years apart, 0:15:43.600 --> 0:15:47.160 they'll still feel each other. Absolutely, You feel the electric 0:15:47.240 --> 0:15:51.720 field from electrons in Alpha Centauri or the Andromeda galaxy 0:15:52.120 --> 0:15:55.120 or halfway across the universe. Absolutely? Is that why I 0:15:55.160 --> 0:16:00.320 feel like I'm being pulled apart? No, that it's like 0:16:00.560 --> 0:16:04.320 maybe the only scientific connection between astronomy and astrology, Like, 0:16:04.400 --> 0:16:09.760 are you affected by the movements of the planets? Well, maybe, 0:16:09.760 --> 0:16:12.440 but it's really negligible. And I also remember that it's 0:16:12.480 --> 0:16:14.720 time delayed. You know, if you if there are electrons 0:16:14.720 --> 0:16:17.800 and Alpha Centauri and somebody wiggles them, you don't see 0:16:17.800 --> 0:16:21.760 those wiggles until until the information comes here, which takes 0:16:22.000 --> 0:16:23.480 you know, which travels at the speed of light, so 0:16:23.480 --> 0:16:25.600 it takes a long time. But you're saying the weak 0:16:25.680 --> 0:16:29.200 Newark force doesn't have that long range, like at some 0:16:29.280 --> 0:16:33.320 point two particles that feel it don't affect each other 0:16:33.520 --> 0:16:35.480 with the weak force. That's right. The range of the 0:16:35.520 --> 0:16:39.560 force is really tiny. It's like the diameter of a proton, right, 0:16:39.600 --> 0:16:42.480 So these particles have to be really close together. It's 0:16:42.520 --> 0:16:44.720 just another way of thinking about whether these two things 0:16:44.760 --> 0:16:47.520 will interact. I think about it's sort of like, you know, 0:16:47.560 --> 0:16:51.240 imagine you're throwing two baseballs at each other, right, They're 0:16:51.320 --> 0:16:53.600 less likely to interact than if you're throwing two basketballs 0:16:53.600 --> 0:16:57.440 at each other, or two um or some really enormous ball, 0:16:57.720 --> 0:17:00.440 some like enormous yoga bouncy yoga ball at each other, right, 0:17:01.080 --> 0:17:03.200 And so the side this is what we call cross 0:17:03.240 --> 0:17:06.439 section in physics, because the cross section of those balls 0:17:06.520 --> 0:17:08.400 tells you how likely they are to hit each other. 0:17:08.920 --> 0:17:11.399 Balls with a really small cross section, like if you're throwing, 0:17:11.680 --> 0:17:14.040 you know, pebbles at each other, it's much harder for 0:17:14.080 --> 0:17:16.679 them to hit. And so the range of this force 0:17:16.960 --> 0:17:20.000 tells you basically the cross section of their interaction. And 0:17:20.040 --> 0:17:22.360 so the weak force is a really small range, which 0:17:22.440 --> 0:17:25.040 makes it less likely to interact. When they interact that 0:17:25.119 --> 0:17:27.160 you know, they still bounce off each other, like anything else, 0:17:27.560 --> 0:17:30.080 just less likely to happen. So what happens when you 0:17:30.119 --> 0:17:33.600 get further away? Does the force just drops off? Or 0:17:34.359 --> 0:17:37.359 you know, like I've heard that at some point the 0:17:37.359 --> 0:17:41.399 weak force doesn't travel far because the particles decay or 0:17:41.920 --> 0:17:45.200 they don't last far far out enough. Yeah, that's a 0:17:45.240 --> 0:17:47.399 really fascinating way to think about it. Um. Yeah, the 0:17:47.400 --> 0:17:50.000 weak force, it just is negligible beyond a certain distance, 0:17:50.080 --> 0:17:53.359 like you know, it's basically zero. And another way to 0:17:53.400 --> 0:17:55.720 answer the question why is the weak force weak? I 0:17:55.760 --> 0:17:57.280 mean one way to say, as well, it just has 0:17:57.280 --> 0:17:59.720 a number associated with it, and that number is smaller 0:18:00.080 --> 0:18:03.760 than the number associated with electromagnetism or you know, the 0:18:03.800 --> 0:18:05.760 strong force, And then of course you can ask why. 0:18:06.240 --> 0:18:08.200 But one way to explain that is to think about 0:18:08.200 --> 0:18:12.040 it in terms of the particles that transmit these forces. Right, 0:18:12.080 --> 0:18:14.560 we think about like the photon. The photon is the 0:18:14.600 --> 0:18:18.760 thing that transmits electromagnetism. Right, what do we mean by that, Well, 0:18:18.840 --> 0:18:21.560 we have this sort of picture that like two electrons 0:18:21.600 --> 0:18:23.840 coming near each other, one of them can shoot off 0:18:23.840 --> 0:18:27.040 a photon to hit the other electron and push it away, 0:18:27.040 --> 0:18:31.160 And that's like how electrons repel via a photon, and 0:18:31.200 --> 0:18:33.480 we we use that same sort of picture for all 0:18:33.520 --> 0:18:36.679 the forces. Actually, but the particles that are associated with 0:18:36.720 --> 0:18:39.800 the weak force, they are not massless like the photon. 0:18:39.960 --> 0:18:44.119 Is the reason electromagnetism extends so far is because the 0:18:44.119 --> 0:18:46.440 photon is massless. It zooms away the speed of light 0:18:46.480 --> 0:18:49.879 and it doesn't decay. Right, Photons can go forever, But 0:18:49.960 --> 0:18:53.240 the weak force has these really heavy particles. They're really 0:18:53.280 --> 0:18:56.040 really heavy, and so they don't go very far before 0:18:56.080 --> 0:18:58.480 they basically decays. Like if I was trying to hit 0:18:58.480 --> 0:19:03.240 you with a bowling ball and my range would be limited. Yeah, 0:19:03.440 --> 0:19:05.320 Or if you, like you know, had taped a bunch 0:19:05.320 --> 0:19:07.920 of stuff together very loosely and then try to throw 0:19:07.920 --> 0:19:09.560 it at me and it exploded in mid air before 0:19:09.560 --> 0:19:12.399 it got to me, like throwing the sandball. At some 0:19:12.520 --> 0:19:17.399 point it might break up a standball exactly. It's like 0:19:17.440 --> 0:19:19.560 throwing a sandball. You know, you're not really getting get 0:19:19.640 --> 0:19:21.440 hit by the full force of the sandball unless you're 0:19:21.480 --> 0:19:25.720 really close. And that's that's fascinating. Like these particles, these 0:19:25.720 --> 0:19:29.480 particles that mediate the weak force bosons, why are they 0:19:29.520 --> 0:19:32.520 so heavy and the and the photon is masseless. That's 0:19:32.560 --> 0:19:34.480 like one of the deep questions in physics over the 0:19:34.520 --> 0:19:37.239 last few decades. And that's why the photon can go 0:19:37.359 --> 0:19:39.760 to infinity because it's massless and it just keeps going 0:19:39.880 --> 0:19:43.640 right exactly. That's why electromagnetism is powerful, and that's why 0:19:43.640 --> 0:19:47.000 it's range is infinite, and the weak force is very 0:19:47.000 --> 0:19:49.680 weak because the things that carry it are very fat 0:19:49.680 --> 0:19:52.520 and slow. You know. It's like, you know, if you 0:19:52.520 --> 0:19:56.000 wanted to send letters ups drivers are super super faster 0:19:56.160 --> 0:19:59.720 driving Lamborghinis, right, and uh, instead you sent it via 0:20:00.040 --> 0:20:03.240 I don't know, um u s mail and they're driving, 0:20:03.280 --> 0:20:05.760 you know, a big, heavy slow bus or something. Um 0:20:05.960 --> 0:20:07.639 your letters is not going to get there is fast 0:20:07.680 --> 0:20:09.560 or might not even get there. So the thing that 0:20:09.680 --> 0:20:13.399 carries the messages, the information of the weak force, is 0:20:13.480 --> 0:20:17.720 big and heavy weeks and that that's what makes the 0:20:18.560 --> 0:20:22.800 blame the messenger. And the fascinating thing is that that's 0:20:22.880 --> 0:20:26.160 really only relevant um sort of late in the universe. 0:20:26.160 --> 0:20:29.359 That's relevant when everyone there isn't a whole lot of energy, 0:20:29.480 --> 0:20:33.199 because the mass these particles makes a difference when everything 0:20:33.240 --> 0:20:35.320 doesn't have a lot of energy. But if everything was 0:20:35.359 --> 0:20:38.560 really hot and dense and and zooming around, then it 0:20:38.560 --> 0:20:41.760 wouldn't really matter what the mass of these particles was, right, 0:20:41.840 --> 0:20:43.639 they have a little bit of mass or not they 0:20:43.720 --> 0:20:46.080 had a lot of energy, wouldn't make any difference. And 0:20:46.200 --> 0:20:48.840 that's why we think back from the beginning of the universe, 0:20:49.160 --> 0:20:53.359 electromagnetism and the weak force had the same strength because 0:20:53.400 --> 0:20:57.120 everything we're just closer together and interacting the same way. Yeah, 0:20:57.200 --> 0:20:59.280 and those particles, the ones that carry the weak force, 0:20:59.440 --> 0:21:01.840 just had enough energy to get further. The fact that 0:21:01.840 --> 0:21:04.040 they had mass didn't really matter because they had so 0:21:04.119 --> 0:21:06.840 much energy it was negligible. All right, So that's the 0:21:06.880 --> 0:21:09.119 weak force. Now we know it's a force, and we 0:21:09.160 --> 0:21:11.919 know why it's weak, and so let's get into what's 0:21:11.960 --> 0:21:15.000 interesting about the weak force? Why is it weak? Um? 0:21:15.119 --> 0:21:17.000 What's weird about it? Why do we have it? And 0:21:17.040 --> 0:21:19.399