Is the universe left-handed?

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Speaker 1: Hey, Jorge, remember when we talked about particles spin trying not to remember you mean, you mean the spin that isn't really a spin. Yeah, And then we talked about particle color. Huh, the color that isn't actually a color. And particle flavors. You mean the flavor that doesn't actually taste like anything. That's the one. Well, I got some news for you. Turns out particles can be left handed or right handed. Hi am orhandmade cartoonists and the creator of PhD comics. I'm Daniel, I'm a particle physicist, and I'm mostly right handed. And welcome to our podcast Daniel and Jorge give weird names to particle properties in the Universe, a production of I Heart Radio, in which we do our best to connect the weird, the strange, the amazing, the bonkers universe that we find ourselves in. Two things that actually do make sense to you, that are familiar in every day Yeah, Because I think sometimes the universe does feel really familiar, you know, and relatable, and I feel like I understand it. But sometimes I feel like the universe is this crazy, unknowable, confusing and totally unintuitive thing that we're all living in. I mean, every time you leave your house, every time I turn on the news. If I just stay in my living room, everything feels so familiar. Why do I have to go outside? Yeah, but I guess. I mean, you know, sometimes the universe and you know, particles and stars and black holes behaving ways that really are don't make a lot of sense to me. Yeah, and it's fast dating. How as humans we try to make sense of them in terms of things that we do understand, Like we talk about the life cycle of stars, even though of course stars are not alive, but you know, they begin and they burn and then they die spectacularly, Like I hope I will die spectacularly one day. I think most people wish for quiet death. Daniel not a spectacular who wants to go out with a whimper man. I want to end with a supernova that sounds just like a physics super villain Daniel in a comic book. Look, my budget from my funeral is not like all coffins and flowers and stuff. It's all sticks of dynamite. Great, I'll be sure to turn on that invitation, all right, um, But the point is that we do our best to understand this weird, cold lifeless, dramatic world in terms of things that do make sense to us. You know, we think of particles as little balls. We think of photons is like waves in the ocean. We think of things as having a life cycle. What else can we do? We try to map the universe into things that we know. Yeah, and so today we'll be talking about a particular property of the universe, or I guess particles in particular. Is that a good way to say it? Say it, um, particular particle property. Oh my goodness, I feel like we're I'm talking to my kids and they're giving me a riddle. Peter Piper picked a pack of pickled peppers. Peter Piper picked a pack of pickle particles. Yeah, we'll be talking about a really amazing particle property that we might not even discovered if it didn't turn out that the universe preferred one kind rather than the other. Yeah, sometimes the universe has a preference. You know, it's just, um, it's just the way it is. Is it just the way it is? It the kind of thing that makes us wonder, like, why is the universe this way and not the other way? Every time the universe has to make a choice and it chooses one direction over the other, um one place over another, makes us wonder why this and not something else. Yeah, So usually is as physicists, we like when the universe is balanced, when it's symmetric and it doesn't make a preference, because then we don't have to know why. But every time it does make a choice, that's a clue. It tells us there's something weird in particular about our universe. It could have been different, right, and so to be on the podcast, we'll be talking about is the universe left handed? M hm? Why didn't we say is the universe right handed? Yeah? Well, because the universe does have a preference, and it turns out it's not the same as a biology interesting, so meaning that the universe is maybe not the perfect symmetrical, un judgmental thing that we kind of wish it were, right, I mean, you wish it weren't. Well, we're always looking for symmetries in the universe and wondering what those means. We have lots of really deep symmetries, like we don't think it matters where in the universe you are. The laws of physics should be the same if you're here or if you're there or you're somewhere else the same way, there's no preferred direction in the universe, no up and down. That sort of makes sense to us, right. We like to think of the universe is like democratic in that way, right, But really it's more of an electoral college kind of thing, which is the source of all of our problems. You know, that's a fascinatingly accurate description because the universe is dominated by mostly empty space. Empty space that contributes most of the energy of the universe, because that's where all the dark energy is. So you no, we we are trying really hard to stay a political on this show. We are applying you know, reason and logic to trying to understand the universe, but of course we have to map it sometimes too, things that make sense to us. Right, So it turns out that the universe is not perfectly symmetrical. It does have kind of a preference for one direction or another, and so that's what we'll be talking about here today. We're talking about the property of particles called handedness right left and right handedness of particles which I don't actually have any hands. Well, I'll give you a hand for that one. Particles, As we know don't have hands, but that doesn't mean we can't talk about handedness, right, and like we call it handedness because it's a property we first noticed of our hands. Like if you look at your hands, the two are not the same. Right, your left hand your right hand are not the same. And even if you put them next to each other, is no way to like rotate your left hand to make it look just like your right hand. They really are differently. The pattern, the order of the fingers is just different from one to the other. Right, there's a our hand. My hand, right hand is not the same as my left hand. It's like a mirror image. That would be word if both my hands looked exactly the same. Though that's kind of a disturbing saying you like symmetry, would you prefer to have two identical hands? Um, well, that's different than symmetry because I feel like it hands are symmetric, but there it's like mirror symmetry. Right, there's a difference between merror symmetry and like exact exactness. That's right, and that's the property we're interested in here today. Things that have a handedness that have a mirror symmetry, like your hand if you put up your left hand in the mirror, it looks just like your right hand does in real life, but the mirror turns left handedness into right handedness and the other way around. Right by the way, like a sphere. A sphere doesn't have a handedness because it looks the same in the mirror. But your hand it does have a handedness because it looks like the other one in the mirror. And so we're interested in, like, all right, here's a symmetry, here's a property. Does universe prefer one or the other. And we know, for example, in people, that there are more right handers than left handers and you and you have to wonder, like why is that? What does that mean about biology or evolution or something? And now we can ask that same kind of question about particles, right, and it turns out that the particles have a handedness and that the universe kind of prefers one over the other. Yeah, it's kind of fascinating. All right, we'll get into that, but first we want to give a quick shout out to Chris McKinnon in England. That's right, we gotta request from your partner, Georgia Arnold, who says thanks for listening to the podcast and for teaching science to others. So Chris apparently is a fan of our podcast in England. So happy holidays, Chris, and happy birthday coming up in January. Yeah, happy birthday, and to everyone whose birthday is coming up in the next year, which I guess includes everybody except for those four and enough every right, I guess that's that's right. We want to be inclusive, but we also want to be accurate, right, And happy holidays to everyone out there, and happy non holidays to all the atheists as well. Are you saying atheists don't know holidays? I think by definition they don't have holidays. Oh man, I don't know this is the topic we should dive into. But um, but yeah, thanks, And if you are interested in writing to us and let us us know what do you think of the podcast, please follow us on Instagram and Twitter and Facebook. All right, well, let's get back on the topic here of the handedness of the universe, and so we might say, to the topic at hand, let's get back to the do the bad puns? Guys, we trailed off into some holiday cheer. We forgot to get to all out the bad puns. But as usually what we were wondering how many people out there knew that the universe or that particles have a preference, or even an idea or or a property called handedness. Yeah, so I walked around campus that you see Irvine, and I asked books if they knew what it meant for a particle to be left or right handed. So think about it for a second. If you were approached by a physicist on a holiday morning and you were asked if you knew whether particles can be left or right handed? What would you answer? Here's what people had to say. Do you know what it means to say a particle can be left handed or right handed? No? No, they don't have hands? Well is isn't it talking about the movement of the current? Um So that's where I can remember from physics I took on the micro level, there's certain orientations and movements happen, and do there are going too one way or the other way? But I'm not superfamulate with outwards unfortunately, not now doing particles with hands? Well, well, I would guess that it has something to do like we're like the electrons around it, maybe more to the blaster to the writer or something all right. Not a lot of people knew that particles have handedness. No, No, it a little bit of pushback, like, nope, particles do not have hands. I thought as well, I'm gonna give a hand to this person here. No. So not a lot of familiarity with this concept. Yeah, which is uh, I guess, I guess I know. I knew about this idea just from talking to you, Daniel another physicists, because I know that it's related to like the spin of particles, right, and how they look at each other in the mirror. Yeah, and it's related to parody. And we did a whole fun video with Derek Mueller of Veritassium about parody and charge parody and its impact on time with particles. It's a gorgeous video. Folks out there really interested in this concept of symmetries and particles, go check it out. I think it's called do Particles Tell Time? On YouTube? And so so, just to clear things up, particles don't have hands. We we've established that, at least we don't think that we've seen, right, they could have point hands, that's right. We have to qualify what we understand here. We have not seen particles hands. It doesn't mean they don't have them. They could be super duper tiny cute, little tiny particle hands. Yeah, that's how they that's how they hold on to each other, they do how they make those bonds. Right, that's how the universe is connect the tiny little hands. That's right. But you know, you can have handedness even if you don't have hands, and let's get into it. But I feel like even if particles were a little spherical balls, which I know they're not, it seems weird that they would have like a preference between right and left, because what's the right and left of a perfect sphere? You're exactly right, and um, if you had a perfect sphere, it's perfect sphere is not handed. Right. To have something be handed you need at least two different directions that you can compare. And so a perfect sphere, however, can spin, and when it spins, the axis along which it's spinning gives you one direction, and then you can compare that spin direction to something else, like the direction it's moving, and you can ask, like, do those two directions line up? This kind of stuff. So particles can have handedness because it's built on top of other properties they have. But You're right, a sphere that has no handedness, it looks the same in the mirror by itself. And and as well, I guess a point as well, right, Like a point would have even less of a less of a hand unless it has plenty point hands right, which is not really the matter at hand. But you're saying that handedness for particles is related to you get like you got to throw in another property into the conversation in order to have handedness in a point particle. Yeah, And here's where we get into murky territory, because handedness it's a quantum property with particles. It's like an intrinsic property. It's like charge right, or it's like spin it's not physically spinning, or there is no place where the charge is. It's just like a label we put on a particle. And so these particles have this intrinsic leftiness or rightness really, and we can make it connected to this other physical thing, but in the end it really is deeply, fundamentally just sort of an internal quantum label that we can never really truly understand. Really, because I've never seen handedness in any of the you know, posters or graphics for the standard model of physics. You know, I see spin, I see charge, I see color, but I never see like left ear righty. You know. Yeah, Well it's mostly connected to the weak force, because the weak forces what revealed to us that handedness was a thing we had to think about and that it was actually important. So I guess we should call it quantum handedness because that's the that's the solution to any confusion in physics is just at a at a word that says you're right. It is confusing, It's okay, don't try to understand it at an intuitive level. It's weird. No, you're right. Quantum X. What we mean when we say that in physics is like, well, this is like some other weird version of X. We're using X because it's similar kind of in some way to the thing you're familiar with. There's an analogy that that's maybe helpful, but it's not really the same thing. Right. It's kind of like how our podcast is known for quantum humor. That's right, only particles get it. It's neither here nor there, but just still try to understand it. That's right. That's what we're getting a lot of quantum clasks and making a lot of quantum bucks. It's it's all theoretical, Daniel. No. But in the case of particles, you can sort of define this handedness by saying, let's look at the direction it's moving, and then let's look at the axis around which it's spinning, and ask are those two things pointing in the same direction or not? And so we call it right if they're in the same direction, and left handed if they're in opposite directions. But that's arbitrary. We could have just labeled them any way. You know. We can call them alpha and beta, or blue and red, or left and right or right and left right. These are just labels we deside. Oh, I see. It'd be like saying, like, some particles like to be positive and green, and some particles like to be negative and blue, and you might call that handedness or some other property. Yeah, some of the properties, but this particular one that we found, it turns out the universe cares about. So you could construct all sorts of things and column handedness, but the universe might be like, yeah, that's fine, I don't care about that doesn't matter to me. But this one is interesting because the universe does seem to care it is something that is important. It changes the way the universe treats these particles, and so it really does matter. Okay, so you're saying that handedness in a particle means that the spin of the particle is sort of a line to its motion. Yeah, And it's a bit confusing to think about the direction of spin because it's going in every direction. Right, it's a spinning thing. It's turning and turning and turning. What if I just turned my head upside down, wouldn't it flip it on its head? Well, it wouldn't change the direction of spin. Right, But so you use your right hand, and if your fingers are curling the direction the particle spinning, your thumb tells you where we sort of define the direction of the spin vector, and it's along the axis of spin. It's kind of like a top if you're spinning a top. M I guess you can spin a top both ways. But it's kind of a screwdriver, I guess, or like a screw it's like clockwise versus counterclockwise. Right, you have to define one direction or the other. And we say that the direction that you're the fingers curl on your right hand is a certain way, and that helps us define a certain direction. And so if the particle is moving in the same same direction that this spin is pointing, where again the spin comes from your thumb. If your fingers curl the way the spear is spinning, we call that a right handed particle. Really. Yeah, So parts of particles don't have the option of moving either way, like they always either move in the direction of spin or not in the direction of spin. Oh, that's fascinating question. Remember spin is quantized, right, and so you measure spin along any axis. And because it's quantized either along that axis or in the other direction, spin is not a infinitely valued quantity. It has to be either positive or negative. It's quantitied. It's this quantum spin. Like let's say that spinning and the spinning direction is up. You're saying that particles can move up and down. They have to move up or down. You can't say the particle is spinning and its spinning direction is up. That's quantum mechanically impossible to know the complete spin direction, right, because there's three different axes, and you can't know spin along three axis simultaneously. Because the Heisenberg is certain principle. Oh, boy, the you have to go the other direction. You say, all right, which direction is my particle moving? All right? That define some direction. Now I can ask is it spinning along that direction or in the opposite direction? I see, And that what I get if I ask it if is it spinning in the direction of moving or not? Is something that particles Some particles will always give you the one answer, and other particles will always give you the other answers. Or is it random? Like a particle can be moving either aligned or not aligned with its spin. That's what we call handedness. If a particle is right handed, then it's moving with its spin. If it's left handed, it's moving away from its spin. Now, some particles, like neutrinos, you only ever see left handed neutrinos. Right handed trinos do not exist. Other particles you can have both a right handed version or a left handed version. Oh, I see, alright. So some particles are ambidexterous. They can right with the right or left hand. But some particles in nature are definitely lefties or right ease. Yeah, And it's it's a little bit more subtle than that. It's like, do you think of the electron and the positron is different particles or sort of two sides of the same coin in the same way. Do we think of like the left handed electron and the right handed electron is two different particles or just sort of like two different versions of the electron, because it turns out nature sees them as different. So the electron can be right or left handed, or you could say it that there are right handed electrons and left handed electrons. Oh, I see, but is it like fifty fifty or what is it? Um? The universe prefers left handed electrons. You mean meaning there are more of them, There are more left handed electrons. Yes, wow, huh so it's kind of the opposite of people. No, that's right. And also for our DNA, you know, our d N A has a handedness to it also, and it's also right handed. All of our organic molecules in our body are right handed molecules. Uh. Interesting, alright, So that's kind of what handedness is is um, do particles like to move into direct in which they spin or do they not? Or that they like to move in the direction which they not spin. So that's a handedness in particles. And so let's get into what that means for the universe is prospects in Major League Baseball, whether there are going to be drafted early or not, and why it matters maybe to you and me. But first, let's take a quick break, all right, Danniel. So you're saying that some particles in nature, like the electron, can be right or left handed, meaning they can move. You see them moving in the direction that they're spinning, and some of them you see them moving not in the direction they're spinning. But some particles, like the neutrino, do have a preference. That's exactly right. Neutrinos are only left handed and anti neutrinos are only right handed. And this is a really fascinating thing that we discovered only about fifty years ago, that this concept of particle handedness is a real thing in the universe. And you know, we've been like over the history of science adding labels to particles as we discover them, we'll we'll see something happen and we're like, well, we can't explain that with the labels we currently have. So maybe particles are a little bit more complicated, like we have to add spin to them, or we have to add flavor or color or whatever to sort of have our theory have enough wrinkles in it to describe all the weird effects that we observe, and so handedness is like one of the latest ones. In the late fifties, people saw these really strange experiments where it looked like the universe didn't work the same in the mirror as it does not in the mirror, and to explain them, they had to add this new property to particles called handedness. Oh, I see, Like, if every particle in nature was right and left handed, we wouldn't even have a name for it. It could just be like, you know, it wouldn't matter. But you're saying it's sort of does matter in the universe. Yeah, we wouldn't know if it was real. Like you and I could right now invent a new particle label right, call its strip nous And all right, the electrons we're gonna say are blue stripe and with red, and those electrons are green striped with white or whatever I'm gonna go with. Bananan is banan is. But if the universe treats particles the same, whether or not johe has labeled them to be banana equals one or banan equal zero, then it doesn't matter. It's not a physical thing, right, It's just like an idea in your mind. It's like literally another thing. Like you would say, that's not a thing, dude, but nobody cares. But let's say somebody doesn't experiment one day and they just and they realize, you know what particles that Joe has little labeled having banan equals one, the universe treats differently than we'd be like, the universe is not symmetric to banananus, and then it would be a real physical thing. That's exactly what happened in physics. People had this idea of handedness, but they thought that's ridiculous. How could the universe prefer one to the other. Clearly it's symmetric. There's two options there. It's just a thing in your head. And they didn't experiment. That proved them wrong. It was like in Clueless, where one of them the other stopped trying to make it a thing. It's not a thing, but it turns out it is a thing. It turns out it is a thing. And you know, there's a lot of really interesting deep philosophical questions. They're like, how many other things are there? Of particles? That are really exists, but we just haven't figured out either the way the universe prefers one to the other or an even deeper question is what if there are particle things that the universe is just totally symmetric to so we will never discover them, Like it is a thing, but we can't tell a thing. Yeah, in which case is it really a thing? I think that's what's happening with the banana is of particles. You guys just can't see it, but I know it's there. Maybe we just need a really big accelerator once you raise fifty dollars and we'll discover bananan this. You wouldn't go to a circle. We're just going to half circle. That's right. We need to sort about elliptical accelerator, you know the been and a curve. Yeah, and forget and forget those cryogetic magnets. We would just use banana appeals to lubricate the particles. It's not a particle accelerator. It's a particle slipper. There you go. Comedy would be a plentiful in this accelerator. Yeah. Okay, so particles have a handing this and so what does that mean? What does that mean that the universe has the preference in some cases or not you saying You're saying it's related to the weak force. Yeah, Well, we have all these fundamental forces of physics, you know, the weak force, the strong force, electromagnetism, and gravity, and they all are different forces. Were trying to understand, of course, how they're related. But they have different effects, and most of them don't care one whit about whether a particle is left handed or right handed. But the weak force is weird, Like the electromagnetic force doesn't care if an electron is right handed or or left handed. It's democratic. It treats those two the same, and the strong force treats left handed corks and right handed corks the same way. It's like, I see you both the same, I am handedness blind. I'm gonna attract you or force you to do something, and I don't care. That's right. If you didn't experiment with the strong force, and you had it set up next to a mirror, and you watch the experiment unfolding in the mirror, you could use the exact same laws of physics that we have in our universe to describe what you see in the mirror. Because in the mirror universe, all the handednesses are flipped, but the strong force doesn't care. It's like, oh, left handed corks now are now right hand corks? I treat him the same. Oh I see the equations kind of work out. The same equations are perfectly symmetric, and the effects are perfectly symmetric, so flipping them does nothing, Like what do you see in the mirror? Could may as well not be in the mirror? Yes, or you can't do an experiment to tell are you in the mirror world or not? As the results of the same interest. But that's not true of the weak force. Okay, so the weak force, it's different different. It does affect particles differently depending on this idea of handedness. That's right. And it was in the fifties of people realized nobody's ever checked to see if the weak force breaks this rule or not. People just sort of assumed it's such a deeply ingrained assumption, like, of course the universe doesn't prefer one or the other. And then the theorists went through and said, well, has anybody ever checked? And people had checked for a electro magnetism and for the strong force and all that stuff, but nobody had checked for for the weak force, and if physicist did it, well, I feel like there are two ways in which handedness can matter. Like one is which are the right or lefties do we see more of? And that's kind of interesting, Like the fact that we see more left handed new trinos and right handed new trinos is sort of one way that the universe is a preference. But then you're you're I feel like there's also another way in which the universe has a presence, which is in through the forces. Like the laws of physics actually applied differently to the lefties or right easy, but those are the same concepts. Right we interact with things using forces, so we only see left handed neutrinos because we interact with them. It's possible there are right handed neutrinos out there that we can't interact with because our forces don't touch them. We only see what we what it's visible and what we can interact with as a whole. You know, we won't recently discovered that there's huge parts of the universe. We barely have hints that actually exist, and so there could be other particles out there that are right handed neutrinos. We haven't seen because we can't interact with them. Oh I see, it's the same thing. It's the same thing. There could they have plot thickens or um passes throughs like neutrinos. We're not I'm not quite sure what how people are getting this, but we're just saying that there could. There isn't more of the left handed neutrinos in the universe. Is just that's the only kind we see. But we don't know if there are right handed neutrinos because we can't interact with them. Therefore, we can't prove whether or not they exist because what we us to interact with them has a preference. It's like a filter. Now, the other particles, electrons and quarks, we can interact with them in other ways that are democratic, right, because the strong force and electromagnetism doesn't prefer one or the other. Neutrinos, we can only interact with them via the weak force. Oh I see. It's the only way we can see them and they and it certainly does prefer it. So there could be as many right handed nutrinos out there in the universe as left handed neutrinos. We just can't see them because the weak force only lets us interact with left handed ones. That's right. And you know in the same way that like the space could be filled with invisible, imperceptible bananas, we can't see them, so are they really there? Well, we have to use the banana force, which I've yet to discover, but I'm sure it's it's on the horizon there. Yeah. And it's fascinating because this effect has to do also with charge, right, because the particle that mediates this thing from the weak force, the W particle, which carries electric charge. So you have W minuses can decay to left handed electrons and W plus is decay to right handed positrons. Okay, so what does that mean. It's relevant because the way we sort of patched up this symmetry is by adding charge to it. You can tell whether or not you're in the mirror world. By doing this experiment, um to see whether things are reversed right, whether the weak force is giving you left handed stuff or right handed stuff. But if you in the mirror you also flip the charge of everything, then the experiment looks exactly the same. Okay, Well, maybe step us through a little bit, like what does it mean that the weak force prefers left handed to right hand, like it only interact with left handed things as far as we know, or or like it only works with left handed things. Yeah. The w bosons in particular will only interact with left handed matter particles or right handed antimatter articles. So left handed electrons, left handed corks, left handed neutrinos, or right handed positrons, right handed anti neutrinos, right handed anti corks. The z the z boson, which is another particle that communicates the weak force, is even weirder. It will interact with both, but it prefers the left hand like interacts with the left lefties more than the rightings. Oh you're okay, now, I guess now. Now you're taking me through the particles that mediate that like helps us communicate these forces. Right, that's exactly right, because the weak forces three of them. Okay, you're saying that the particles that communicate the weak force, those are the ones that have the preference. It's not like the concept of the weak force as a preference, but the particles that communicated have a preference. Yeah. Well, the particles, they are the manifestations of the force. Right, we think about these particles as doing the duty of the force the Jedi does. The Jedi order exists without the Jedi, you know, they're carrying out the mark in orders, the Jedi hierarchy. So well, I mean, it's it's like saying like, it's not that the police force has a preference for left handed right hand the people. It's more like, you know, it's like parking offers have a preference, but uh, you know, detectives have a different preference. You know what I mean, Like, it's it's it's it's different than saying that the whole thing has a preference. Yeah, and you're right. And there are three particles there, the media, the weak force, the W plus, the W minus, and the Z those are sort of like the analogies of the photon. But for the weak force and the W plus and the W minus they only interact with left handed particles or right handed antiparticles. I see. It's like that's how the preference manifests itself. It's like the messengers for this force have a preference. That's why we can't communicate with right hand the netrinos, because the messengers are kind of blinded to that the other kind. Yeah, and that's how they discovered it. They took a bunch of atoms and they lined up their spins in a certain direction, and then they saw which do direction do the particles shootout? Do the shoot out in the same direction of the spin, in which case they'd be right handed. Do they shoot out against the direction of the spin, in which case they'd be left handed. And they sort of expected it to be balanced so you couldn't tell, Like they expected to get the same number of right and left handed particles, so that you couldn't tell if you were in the mirror world. But what they saw was a total shocker. Not only was it not balanced, but it was totally unbalanced, like zero right handed particles a left handed particles were shot out. And so the weak force doesn't just prefer left handed particles, It like maximally prefers it as far as we know. I mean, could it be producing right hand at once that we just can't see or interact with. It could be there could be right handed particles that we don't interact with, but they don't interact with the weak force, so they have to be some other new force for us to interact with them. If they interacted via the weak force, we would see it. Well, but I mean, I guess one question is, how do we know it's the weak forces fault or those particles is fault? Like what if it's our fault? You know, like what if we were parents, it's always our fault. Yeah, what do you mean our faults? Well, I mean, like maybe maybe there's a new kind of boson we'll call it the ex boson, which does interact with the right ten particles through the weak force, but we just don't interact with the ex boson. Totally possible. Yeah, there could be a whole complicated sectors of particles out there that interact with each other but not with us, and we just haven't seen them or haven't yet discovered them. Nobody's invited us to the party. That's the whole hypothesis for dark matter, right. We know that there's a lot of dark matter out there. We don't know what kind of particle is it. We don't know if it feels forces with um among those particles, we don't know if there's like ten different dark matter particles are always changing into each other. So there could be a whole complicated sectors and oceans of physics there that we are not primy tune because we don't have like a portal into them, no way to interact with anything that's happening there. Right, If only we had that banana particle accelerator, it would open new doors to the universe for us. It would peel away the layers hidden from us. It would slip us into a new era of physics. Al Right, well, that's that. That makes it a bit clearer for me, and how the universe has this preference, and so let's get into why it matters to the universe and maybe to us. But first let's take a quick break, all right, Daniel, So the universe apparently prefers lefties. You know, I think left handed people always have felt pretty special, is my understanding. And now they know why, and now they know why the universe likes you better. Yeah, well, the weakest part of the universe at least likes them better. Oh no, that's not true. Gravity is the weakest force. Week the weak forse just sort of has that name. But it it's fascinating, you know, not only that the universe is asymmetric that seems to notice that there's a handedness, but that it prefers this one, and you can wonder, like, why don't we live in a universe that's asymmetric the other way that prefers right handed particles right where the weak force interacts only with the right handed particles. It's this kind of arbitrary seeming choice that makes us wonder about like the multiverse right, well, um, meaning like maybe it's weird that it has a preference, So there must be a twin out there who is right handed. Well, that's the symmetry in your brain screaming out for an explanation, right, I think there must be balanced, but there doesn't have to be. You know, imagine you're at the control panel of the universe in the first moment of the Big Bang, when the laws of physics are being set in stone, and you have to choose left handed or right handed universe. You know, how is that choice made? Are there a billion universes out there and it's randomly assigned for each one, or is there some deep underlying principle of physics that demand hands that the weak force be left handed? There could be no other way? Or could they could it just flip the coin? It could be We we don't know, Like according to our current understanding, you could write consistent laws of physics where the weak force um prefers them equally, or the weak force prefers only right handed particles, or were prefers one by a little bit. We don't understand why it is this way. Does it have to be this way? We have no reason to believe it has to be this way, and yet it is so. That seems to me like a clue. Right, do we know in people why some people are left handed or right handed? And does it depend on genes or is it just some random process um Well, based on my deep expertise in biology from being married to biologists, is she right handed or left hand? She's right handed, but we have some lefties in her family. There's actually two layers of answer there. One is people like what they prefer to write with, and we're mostly right handed. We don't know why, And it's again a great question, like was that just an arbitrary choice that the brain decided to specialize and this side of the brain is better at this, and the other side of the brain is better at that, And maybe there were equal populations at some point and then it just sort of randomly drifted in one direction. We just don't know. Um. And then there's this deeper question about the chirality of molecules in life. All the molecules in life, including d NA, have a corality that's right handed, which means they have the same sort of um orientation when you rotate the object right and like molecules have a mirror image version of themselves too. Precisely, every single organic molecules right handed. And if you were fed like food made out of left handed molecules, you couldn't eat it, like they die, you cannot process it. And so that's another just like seems like an arbitrary choice could have been something else. Um, we don't understand any of these things. And I don't know if the if the mystery of particle physics handedness is connected to those at all, because it's definitely the other direction, or if this is just sort of a mathematical connection where you can identify handedness and sort of see a similarity in the sort of question. Well, I see, huh, Like, um, like everything that might be possible would have a handedness preference or something like biology particles you know, like just a fundamental you know, property of of existing. Yeah, but it makes our universe interesting, and for example, the reason why the weak force is so weird and so left handed is one of the reasons why the Higgs boson is so fascinating. What do you mean, Well, the Higgs boson, what it does is it connects the left and right handed particles together to give them mass. It interacts with the left and the right. It touches, it talks to both of them, and to talking to them together is how it gives those particles mass. And neutrinos we don't know. We think they have mass, but we don't quite really know how much mass they have and how they get the mass, and do they get it from the Higgs boson or not. It's a whole bit complicated question. But the Higgs, it treats the left and the right totally equally and sort of combines them into one combined particle that has a specific mass. Right, But I guess the main point is that the universe has a preference for left or right hand. It is, it seems, but we don't know why it has that preference. Right, it's a big mystery. Right, And it's weird. Yeah, it is weird. And if it wasn't for this little effect in the weak force, which took a long time to discover. We wouldn't even know, so it could have been that, you know what if the weak force was totally symmetric for some weird reason. Particles have handedness, but we didn't even know, like that they have this property, Well, we wouldn't care, I guess, right, I care? I care. I want to know the truth, man, not just what's relevant for some excises. You want to see all the features, even if you can't see the features, of course. I want to know what does it mean to be a particle? All right? What are the number of labels you need to define a particle? Mass, spin, charged, color, flavor? Why all those things? What do they mean? Why this and why not that? Why not bananimists? To me, these are really deep, fascinating questions about like the very nature of the universe. So yeah, I want to know, Like if you found out half of all particles had an asterisk next appin to them, But no, it didn't matter at all for anything else, Like nobody would care, but you would care me and all the other particle physicists in the world, and anybody who cared about understanding the nature of reality. But yeah, you're right. Nobody else you like, why does that have an asterisk? I see, all right, well I want to know why the universe has an asterisk? All right? Well, I think this is all just a big lesson on ways in which we explore the universe. You know, we look for interesting phenomenon and interesting preferences that the universe has, and that tells us something about how it's all put together. Yeah, and we don't understand the importance um and the ramifications sometimes of these things. Like people thought about particle handedness as sort of an abstract idea a hundred years ago when particles were first being understood. They thought, now, whatever, it's just a mathematical curiosity. It's not relevant, and then later turned out to be relevant, and it might even turn out to be more relevant. Maybe we'll discover a new force that's very powerful and does prefers left to right or right to left or something like that. So it's it's worth just sort of like exploring and trying to understand because you never know where the next big discovery is going to be. Yeah, it would be pretty cool. Would you like Daniel to have a hand in that discovery? Only, but only if it's a left hand. I'd like to discover it. And then I've got like you to give me a hand when I did. You'd like to get both your hands on this discovery. I just want to get my hands dirty, okay. And that with that, we've exhausted all the bad puns, Daniel, so maybe we should wrap it up. That's right, we've done all the left handed punts and the right handed punts. Well, thank you all for listening to me. This is a fascinating question about the sort of deep nature of the universe, us in this stuff that makes it up, and how we understand it in terms of our macroscopic ways of thinking, flavor of color, spin, and now left handedness and right handedness. Yeah, so we hope you enjoyed that. Thanks for joining us. On the other hand, we're not done yet. We're gonna do the mirror mirror image of this podcast episode, but the whole thing backwards, the back course, and we'll say the universe has a preference for right handed particles. We've got to do it backwards and positively charged. And where the jokes are good this time, that's right, where I make the jokes and you laugh at them all right, Thanks everyone for tuning in, and I hope that podcast reached a parody of our other ones and it's not a parody of itself. See you next time. Before you still have a question after listening to all these explanations, please drop us a line and we'd love to hear from you. You can find us on Facebook, Twitter, and Instagram at Daniel and Jorge That's one Word, or email us at Feedback at Daniel and Jorge dot com. Thanks for listening and remember that Daniel and Jorge Explain the Universe is a production of I Heart Radio. For more podcast from my Heart Radio, visit the I heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.