Daniel and Kelly’s Extraordinary Universe - How was antimatter discovered?

Episode Date: December 24, 2019

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I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Nielbornet and I discuss flight anxiety. What is not a norm is to a lot. allow it to prevent you from doing the things that you want to do, the things that you were meant to do. Listen to therapy for black girls on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Hey, Jorge, did you know that there are physics truthers?

What? I know there are particle theorists, but I didn't know there are conspiracy theorists. Yeah, conspiracy theorists, some of them don't believe that anti-matter is a real thing. So they're anti-antimatter? All matter matters. Well, do they just think that you made up this concept of antimatter? Yeah, it turns out a lot of people don't think antimatter is real. They don't believe in it.

Well, maybe they just need proof, you know? Maybe they're not crazy. They're not bananas. Well, it turns out the proof is bananas. Oh, are bananas anti-matter? No, but it turns out bananas produce antimatter. Hi, I'm Jorge. I'm a particle physicist. And I'm Daniel. I'm a cartoonist, but I'm not the author of Ph.D. Comics.

And those are the anti-versions of the real us. host of this podcast, Daniel and Jorge Explain the Universe, a production of iHeard Radio. Although, since you've been listening to me talk and talk and talk for all these years, by now you're basically a particle physicist. That's right. I feel like I talk to you more than

you probably talk to your grad students, so you probably should give me a PhD in physics. Shh, don't tell my grad students that. Do you allow them to hear this podcast? Do you let them out of their basement every once and a while? I'm curious if they listen. I think I've mentioned it to them. Actually,

Some of them appear in our interviews from time to time. Oh, I see. People who can't say no. That's right. I wonder if it's extra stressful for them. If they say no, are you going to judge them based on what they know or don't know? No, I think it's extra stressful if they say yes. And then I ask them a particle physics question they really should know the answer to.

Then they're on the spot. And you have them on tape. I have them on tape, exactly. For the podcast universe to listen. That's right. But the goal of this podcast is not just to embarrass my. graduate students and put them on the spot, but to teach all you people out there about the amazing universe of particles and stars and bananas that we all get to live in.

That's right. All the things that exist out there in the universe and all the things that maybe don't exist or that exist in a constant state of denial or antinous. That's right. Or things that currently only exist in the minds of particle theorists, ideas about what the universe might be like, that we don't know if they are real. Right? Because even the things that might not be real tell us a little bit about how things really are and why they are they're where they are, right? That's right. And in physics, we have this sort of cycle of people making predictions and saying, what if the universe works this way? And then people going out to check and say, hey, turns out you were wrong. Go back to the drawing board.

And there are many, many beautiful theories out there that people came up with that they were convinced were real, but then were confronted by the evidence that they're not. That's right. There are conspiracy theorists even in physics. There are people who are skeptical about the things that physicists have found, right? Even physicists themselves who are skeptical. Well, it's our job to be skeptical, but we like to think that it's sort of a reasoned skepticism. You know, when presented with the evidence, we don't come up with an even more elaborate conspiracy theory to deny it. We accept it. We move on. But it's true that some of these ideas that are in the minds of physicists, they can be kind of hard to accept. And some people still out there think that they're just ideas that they're not actually real.

Right. Because it's kind of an interesting cycle in physics where you might see something in nature and then you come up with a theory and then you do an experiment that valid. dates or disproved as theory and then you come up with more theories and so it's like this weird and interesting loop and so it's hard to tell sometimes where ideas come from yeah especially in particle physics we seem to oscillate between two modes one is where theorists are leading the field where they have ideas for what they think is happening in the universe and then experimentalists have to go out and basically check those ideas and the other mode is where experimentalists are taking the lead where we're out there finding crazy stuff nobody understands and theorists are

scrambling to keep up to explain all the bizarre stuff that we've uncovered so what do you think it determines who's taking the lead is it like just who has more free time in their hands to play around and discover things or who's who's more suspicious of the other it's just up to nature it's just up to how much stuff there is to discover you know in the 50s and 60s they were discovering a new particle every time they turned on the accelerator. They called it the era of the particle zoo, whereas these days it's like decades between particles, and that gives the theorists a lot of time to be creative, to come up with new ideas, to say, maybe it's this, maybe it's that, because we don't have anything to sort of

constrain them. Right now, we're in a really theory-driven mode of the field. Is there a song for the particle zoo? I feel like there should be a song. Particle zoo, particle zoo, doing the things, particles do. there you go wow on the spot jingle making awesome that's right by they might be particle physicists no you have a PhD in jingle engineering granted but it's interesting history right in the 50s we were discovering new particles nobody understood and in the very early days of particle physics like

the first particle was discovered right that wasn't predicted it was discovered and then the photon was like thought up to explain an experiment that people had seen so in the very beginning it was driven by experiments. But these days, of course, it's driven more by theory. And so today we'll be talking about one such thing that has been seen or that some people have seen in nature and physics, but that maybe some physicists don't really believe that it exists. Oh, I think most physicists believe it, but I just wonder about the general public. Oh, so is this, when you say truth is you mean physicists or people? I mean people. I mean. because physicists are not people is that what you're saying you just trap me you totally led me

into a trap there daniel are you a person or a physicist pick one no i think that uh you know this is really fascinating because it's one of the first things that was ever predicted before it was seen this is the first time somebody said maybe this crazy new thing does exist out there in the universe somebody go look and sort of sort of the dawn of the new era and it's taken a long time for people to believe that it's real and some people out there still don't. So I guess at some point this was a topic where some people thought it was true but a lot of physicists maybe didn't think that we would see it or that it would be proven to exist. That's right. Between the prediction and its discovery, it was contentious.

And it's a pretty interesting topic because it talks about a huge part of the universe that is both intriguing and super dangerous. Yeah, and fascinating, and you hear all about it in popular culture. Like, it's everywhere. It's even in Dan Brown novels, so you know it's got to be cool. Oh, oh, man. It must be true then if it's in a Dan Brown novel novel. Yeah, I think those are all heavily researched.

The Da Vinci particle. All right. Well, so today on the podcast, we'll be asking the question. How do we know? matter is a thing or an anti-thing. What's the correct way to... How do we know antimatter is not a thing, or... How do we not know that antimatter isn't not a thing?

Yeah, there you go. Let's put in more negatives. No, I think... I'm anti-that kind of use of language, Daniel. I think that often the history of particle physics and the topic of particle physics is framed from a theoretical point of view. Like, what is our understanding of the particles that's out there? And that's cool.

But for me, I'm an experimentalist. I want to know, like, how do we know these things? Like, you say these particles exist, how do we know that it's real? What experiment, what thing happened that proved to us that it had to be there, that it's part of the universe? So we did a podcast episode about how do we know even particles exist about the electron and how do we know photons exist and this kind of stuff? And why are there muons? And so this is sort of in that series of like telling people about the moment when we confronted something that proved to us that this new thing had to be a part of our universe. Yeah, and so antimatter is a word, or two words put together, and we kind of know it's a thing,

but we were wondering how much people out there know about it or that they know that it is a thing and not just one of those crazy physics ideas that are floating around. Yeah, so I went around, and my goal was to ask people if they knew how antimatter was discovered. But I had to back up because it turns out a lot of people didn't even know. know that antimatter actually had been discovered. So they didn't know that it was a thing. Yeah. That was sort of surprised at me, but

listen to these interviews and think to yourself, do you know how we discovered antimatter? Here's what people had to say. I know about it. I don't know how they discovered it now. No, I don't. I have heard of it in like science fiction and stuff, but I don't know how the logistics

of it would even be possible. I'm not too sure, but I know like the phrase. I heard it like a lot of times. Is it a real thing or just science fiction? I, like, it's kind of like theory, so it's not too sure. I think they are because probably read it. Something about it keeping the universe from expanding too fast. So how do we know antimatter is a real thing?

Like, how was it discovered? I don't know exactly, but my best guess is that it could be shown through, like, how the universe expands. But it seems like it's being limited by a certain... I think it's predicted to be anti-matter? Right now, it's all theoretical, isn't it? I don't, like, have we actually done anything with, like, large hand-on collider as far as hayni matter? Yeah, I'm not sure.

I don't know. I don't know what that means. For knowledge, it is just an idea. It's a real thing. Okay, how do we know it exists? By calculation. Okay, so I know working models. Uh-huh.

To make your... to accommodate the amount of our understanding of matter in the universe. Are you thinking of dark matter? I thought there was some anti-matter, dark matter connection. Oh, okay. Not that I'm aware of. Okay, that's good to know. So, anti-matter, well,

it probably doesn't exist them. I mean, if it were, no, wait. This goes to show that I know nothing about particle physics. But there's something... You should listen to my podcast more often. I would love to listen to your podcast, and I'm sure that there's something I would learn from it. Anti-matter is a real thing as a counterpart to a regular matter, right?

So how do we know it exists? Because to create matter, you have to also create antimatter, and it's been a proven reaction, I think. And we know that it exists despite not being able to necessarily. necessarily detect. I have not heard of that term, actually. All right. So it sort of seems like people are skeptical about it.

Or they weren't, not a lot of people seem sure that it is a thing. Like they talk about it like it's a theoretical thing or it's not proven or it's an idea. Maybe actually I just realized maybe it's because it's in a Dan Brown novel and they thought, oh, well, then it must be BS. Thank you, Dan Brown and the Da Vinci Code. That should be called like anti-science communication. Anti-science. I don't think he claims to be a scientist or it claims to be a work of non-fiction.

No, but you know, when they made that movie, of course we're referring to angels and demons, Stan Brown's novel about an anti-matter bomb, in which the science is mostly right, actually, about antimatter. But when they made that, yeah, they did. Yeah, the science in theirs is mostly correct. But they made that movie, they filmed it actually where I was working at the time, because I, I was at CERN and they were filming the movie at CERN. Oh, yeah? And then I watched the movie.

What's that? Did you get a cameo next to Tom Hanks? Only the most VIP of VIPs got to give Tom Hanks a tour. So I was like not even in the top 500 list of people who would get to have lunch with Tom Hanks, unfortunately. But now, now you would be. No, I'm making the top 450. Yeah, I'm really moving up. But the cool thing was that when I watched the movie, they had taken our like,

normal, boring workspaces, which is basically just a bunch of computers and screens, and they had science fictioned it up. So people had, like, cool heads-up displays and, like, fancy interfaces with their computers. Lasers, adding some lasers, lab codes. Retinal scanning devices. And I thought, that looks pretty cool. We should upgrade the way our office works to look like the movie. You're, like, checking your pocket and looking at a metal key, you're like, hmm, reality versus movie world.

But it was cool to see what Hollywood's best designers would do with my office. Pretty cool. All right. So it seems like people are not quite sure that it's real. They think it's maybe theoretical. Do you think maybe they were confusing antimatter with other things like dark matter or energy? I hear that a lot, actually. I think that people know that there's something out there as a mysterious counterpart to matter.

And it turns out there's sort of a few mysterious counterparts to matter. Right. there's this whole antimatter thing, there's dark matter, that there's super particles, and so... There's antimatter, there's quasi matter, there's sort of matters. There's exotic matter, you know. Oh, yeah, no, that's a real, potentially could be a thing thing. Splatter matter. There's mats matter.

Yeah, and now you're making me matter matter, and so there's sort of a lot of different ideas to keep track of, and so if you're not like a particle physicist like you are, then maybe it's hard to keep your finger on on which ones are real and which ones are theoretical. Right. And I have to say anti-matter does sound a little ridiculous, does it in? It sounds like 1950s science fiction. It's anti-matter. It's like matter, but it's anti.

The whole concept is absurd, right? But as we said on this podcast, absurdity is no obstacle to reality, right? Turns out the universe is kind of bonkers. Yeah, I feel that way every time I read the news, every morning these days. It used to be just physics, and now it's also politics is bomb. years. But anyways, so yeah, let's talk about antimatter. And we have a whole episode about antimatter. If you scroll through our archive, you can find that episode and learn a little bit more about it. But here we'll just kind of go over quickly about what it is and how it's not actually

dark matter. That's right. Antimatter is not dark matter. It's a whole other enormous, fascinating puzzle about the universe. Antimatter is a statement about particles and patterns. It's noticing that particles come in pairs. And so some of the particles that we've discovered, the electron, the muon, the quarks, there's another particle that looks just like them, except it's the opposite in a couple of ways. And so, for example, the electron is a particle.

We know it. We love it. We're made of it. It's an ice cream. And there's this other particle called the positron, which is just like the electron except it has a positive charge instead of a negative charge. It has other negative things about it, right? like the opposite spin or the opposite quantum color and other kinds of charges, right, that are different?

Some of the other charges for the forces are opposite. The electron actually doesn't have a color because it doesn't feel the strong force, but it has the same mass and spin. So the positron are the same in mass and quantum spin. They're both spin one half, and they have exactly the same mass as far as we know, but they have the opposite electric charge.

So you might just say like, oh, well, it's just a different particle. And it is. It's a different particle, but there's definitely a relationship there. So we group them together. And this is what we do all the time in physics and especially in particle physics is we're looking for patterns. We're looking for relationships that help us simplify. We're looking for symmetries that give us insight. And so it's interesting, not just because the electron has this weird partner particle, but so does the muon.

And so do all the quarks. Right. And we call it matter and antimatter because the ones we call matter are the ones that make of most of the things we see. around this, right? Like positrons and anti-meoans and anti-quarks, I'm not made of any of these things. I'm made out of the regular versions, the pro-versions. That's right. You're made of the regular versions, but you're right also that we call them regular versions because they're familiar. They're like the first ones we encounter because they make up the world we know. And so there's nothing anti about the other ones. They're just sort of not the first ones we found. Maybe a different

word might be like mirror matter or symmetric matter. That's actually already taken. There's a whole other theory about mirror matter. We can talk about it another time. It's a crowded field of terrible names for particles in physics. You're running out of English words to append to your existing physics concepts. Is banana matter taken? Banana matter is not even an idea yet. Not until this podcast comes out.

Is banana matter ever a phrase anybody's ever heard in their mind? But it's fascinating because it seems to be like a thing. It's like a symmetry in the world. You know, like a lot of these particles which exist, there is also this other one of them. In the same way that we like notice that electrons and muons and tau's have a relationship, right? They all have the same electric charge and the same weak interaction and they're organized in a similar way, but they have different masses. So there's like these different directions along which patterns sort of form. All these particles are kind of different versions of each other.

Like one of them has a little bit of this more or this one has the opposite of that more. But they're all sort of particles that we know and love because some of them make us who we are. That's right. And we're tempted to define one of them as like the normal one. But again, that's just the first one we discovered. It's like, you know, what's real chocolate? Dark chocolate or white chocolate. You know, maybe if you grew up in a family or white chocolate was the first thing you ate,

then dark chocolate would seem to be like the anti-choclet to you, right? Yeah, I think we should do that. Just call it anti-cholklet. And remember also the antimatter has positive mass, right? As far as we know, it's made of the same kind of stuff. And so it is anti-matter because it has the opposite charge. And if you collide matter and antimatter, they interact and turn into light and turn into energy. But in that sense, they're just more matter.

It's just, you know, they have this relationship. We could have called it something other than antimatter. We could have called it oppositely charged matter or something. That's a little bit longer to fit into a phrase. It didn't focus group as well. Yeah. All right. So that's what antimatter is. And there's this whole mystery about how most of the universe seems to be matter and not antimatter, which we got into in our last podcast about antimatter. But in this case, this one is more about how we discovered it and how we know that it actually is a thing, right? That's right. The history of antimatter is like almost 100 years old now. It's sort of surprising. But positrons, the first antimatter particle ever discovered, were found.

you know in 1932 so we've known about them for a long long time which kind of surprised me that people still don't necessarily believe that they're a thing or are aware that it's a thing because it's been a thing for decades people right well i think antimatter is anti-celebrating birthdays so that's probably why maybe nobody has noticed but uh let's get let's get into whether or not antimatter really is real or theoretical in how we know that it's real or anti-real whatever the case may be But first, let's take a quick break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys.

Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight.

That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Oh, wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't. trust her. Now he's insisting we get to know each other, but I just want her gone. Now hold up.

Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio about Apple Podcasts or wherever you get your podcast. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast.

Here's a clip from an upcoming conversation about exploring human potential. I was going to schools to try to teach kids these skills and I get eye rolling from teachers or I get students who would be like, it's easier to punch someone in the face. When you think about emotion regulation, like you're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome. result of it if it's going to be beneficial to you because it's easy to say like like go you go blank yourself right it's easy it's easy to just drink the extra beer it's easy to ignore to suppress seeing a colleague who's bothering you and just like walk the other way avoidance is easier

ignoring is easier denial is easier drinking is easier yelling screaming is easy complex problem solving meditating you know takes effort listen to the psychology podcast on the iHeart radio app Apple Podcasts, or wherever you get your podcasts. All right, Daniel, so anti-matter is real, or is it anti-reel, or anti-fake, which makes it real. I'm so confused. It's really, really anti-real, so yes, it's real. That did not help. Okay, so it's real in the sense that not only can it exist in theory,

but you can actually see and touch antimatter. You can see and touch antimatter. I don't recommend actually touching any antimatter because it's quite reactive. But it is a thing. And, you know, there's sort of two ways something can be a thing. One is it's in the list of particles that can exist in the universe, like the potential particles. And the other is that it's actually made,

that it really exists. You can imagine a universe where that's cold and dead and the only thing in it are photons, for example. And you could, in theory, in that universe, have electrons that just don't exist, right? So one thing is like being on the list of potential particles, the other is actually existing. And antimatter is both,

but it started off on the theoretical list and then people actually found it. You mean people looked at the equations of the universe at the time and they said, you know, we have a little pocket here where there could be like an electron on with a positive charge. Like there's nothing that would prevent the equations from making this real. So you're saying that's one way that something can be real if the equations point to it as

being possible. Yeah. And more than just the equation saying it's possible, you could prove that it exists, but it doesn't have to always actually exist, you know, like the Higgs boson, right? The Higgs boson, we know it's a thing, but it doesn't actually like get created very often. You know, you need very special circumstances to actually make one. So it's sort of like knowing that the recipe works and actually making the cake. Right.

It's like unicorns can exist, but maybe they're just technically aren't any right now. No, unicorns, no. What's the difference here, Daniel? But no, antimatter is real. It occurs naturally in cosmic rays. You don't actually need like a particle collider or special physics lab to make it. It's created in collisions in the atmosphere. Every time you have radioactive decay, you can create antimatter.

Sometimes these decays will create anti-neutrinos or anti-electrons or stuff like this. Really? In our atmosphere, we're getting rained down. Wait, it's a regular matter is coming from the sun as cosmic rates, hitting the atmosphere, and then in those collisions, you're saying antimatter is produced. That's right. Anti-matter and matter can turn into each other. right?

Photons, for example, can turn into a pair, an electron and a positron. One is matter, what is antimatter. All you have to do is follow the rules of physics, which say, like, conserve electric charge, but if you have photons, they can turn into matter and antimatter. So in the atmosphere, because of cosmic rays,

you have all these crazy, complicated, high-energy collisions, and some of those just turn into antimatter particles. Does that mean we're constantly and currently being rained down upon by antimatter? Absolutely. It is antimatter rain. I think that was a song by Prince, wasn't it? Yeah, anti-prince. But wait, I thought it was dangerous. How can I be getting rained on by antimatter and not exploding? Like you said, I would. It is dangerous in high quantities, but there's not that much antimatter.

Just like, you know, there's radiation coming from the upper atmosphere all the time, and radiation is also dangerous. protons and muons that go through your body have the opportunity to damage your DNA but there's not that much of them and so the higher you go up in the atmosphere the more there is just particle radiation and some of that is antimatter so what happens if a positron

hits your arm well it encounters an electron and it turns into a photon that photon has the energy that's the equivalent of twice the mass of the electron because all that mass got turned into a photon but that's not that much So, you know, one bright little photon gets created.

Should I be wearing anti-s sunscreen then? There's no sunscreen you can wear to protect you from antimatter. Or does antimatter just make me glow in a way that's desirable? Anti-matter gives you an anti-tan. So actually, what you want to do is use antimatter. Yeah, you do look brighter, I guess, in a way. So it's almost like your... No, the amazing thing about antimatter, though, is that it is really energy-dense

because it converts all of the mass that's inside of it into energy. So if you had, for example, like a raisin's worth of antimatter, which is a lot more than one positron, right? It's 10 to the 23 particles or something. Then that would be as much energy as a nuclear bomb exploding. But again, it's a much bigger dose. And in the atmosphere, you get, you know, a few positrons at a time. And it's not just the atmosphere.

Your favorite snack actually is an antimatter factory. What? Yeah, a random banana has potassium in it, As we've mentioned before, potassium is unstable, and it decays radioactively and produces one positron every 75 minutes. One positron, like a sitting banana, will shoot out a positron, or does it get caught by the other, you know, banana electron? Bananons. It depends, I guess, where it gets produced. If it's produced in the skin of the banana, it'll shoot out into the air.

But, of course, positrons don't last very long because they interact with electrons. But, yeah, your favorite fruit, whether it's sitting on the table or, you know, in a high-speed banana accelerator or whatever you do with your bananas, produces about one positron every 75 minutes. It doesn't get stopped by the peel electrons. Yeah, if it's produced in the center of the banana, then it could. But if it's produced near the edge, then it could make it out of the banana into the air. Well, maybe that's where I get my superpowers, Daniel. Anti-matter. You get that banana's proportional strength?

Yeah, there you go. I can make anyone slip and fall. That's my superpower. I can make anyone uncomfortable with my banana chewing. All right, well, let's just slide on past that discussion. Yeah. All right, so antimatter is real. It is a thing.

It's all around this. In fact, you're probably bathed in antimatter, even though you maybe didn't know it. And you can also, like, make it in a lab, right? Like at CERN, you guys have been making anti-protons and anti-hydrogen for a while. Like you have an antimatter factory there. Yeah, that's right. And the reason is that we're curious about it. We're curious about like how symmetric are matter and antimatter.

You know, for example, can you make an antiproton and pair it with an anti-electron to get anti-hydrogen? Does chemistry work for antimatter? You know, can you get enough of it to test its gravitational properties? We don't even know if antimatter feels gravity the way matter does or if it feels like anti-gravity because we've just never made enough of it. Really? The equations don't tell you whether it should have mass or anti-mass? Yeah, because it's really hard to measure the gravitational force on a particle

because it hardly has any mass. And in the history of particle physics, we've made something like 20 nanograms of antimatter ever total. And so it's pretty hard to measure the gravitational effect of such a tiny scrap. But you have made anti-protons and anti-hydrogen, which is pretty cool, right? It's like a hydrogen, but the complete opposite.

Yeah, and as far as we can tell, it works exactly the same way as a hydrogen atom. So they get into a bound state, they can get excited, they emit photons, it's exactly the same. So it's super fascinating, either to learn that they're different or to learn that they're the same,

you know, and it brings up all sorts of interesting questions. Like, why? Why is there anti-emortons? matter. It seems like such an interesting clue, like, why does universe have this weird reflection, you know? It has all these reflections. I love all these symmetries in particle physics, but each one

should tell us something about the universe. They're a deep clue that says, here's something fascinating that's going on. We just don't know what it means. Well, you know, some people are just really contrarian, you know? And so maybe the universe is just like, just being anti-an-for-no reason other than to just be anti.

But if it, but if antimatter exists, then why aren't there other sort of reflections. You know, why can't you have all the same particles but with different spin? Oh, well, that's super symmetry. You know, why this reflection, not other reflections? Anyway, it's kind of stuff that makes me wonder.

Right. Do you think if these other mirror images exist, do you think they would have better names in physics? Like, actually good ones? Because they're to be the opposite. Well, they can't have much worse names. There you go. All right.

Well, it does exist. It's real. You can make it in the lab. It's my banana makes it on a daily basis. And there are still a lot of open questions about antimatter. So now let's talk about how it was discovered. Because that's a pretty interesting story as well. And what it could mean for the future of the universe.

But first, let's take another quick break. LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently the explosion actually impelled metal glass. The injured were being loaded into ambulances. Just a chaotic, chaotic scene. In its wake, a new kind of air.

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This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating.

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I was going to schools to try to teach kids these skills, and I get eye rolling from teachers or I get students who would be like, it's easier to punch someone in the face. When you think about emotion regulation, like, you're not going to choose an adaptive strategy, which is more effortful to use unless you think there's a good outcome as a result of it, if it's going to be beneficial to you. Because it's easy to say, like, go you go blank yourself, right? It's easy. It's easy to just drink the extra beer. It's easy to ignore, to suppress, seeing a colleague who's bother me. you and just like walk the other way avoidance is easier ignoring is easier denial is easier drinking is easier yelling screaming is easy complex problem solving meditating you know takes effort

listen to the psychology podcast on the iHeart radio app apple podcasts or wherever you get your podcasts Okay, Daniel, so how is antimatter discovered? Were they not looking for it and found it? That would be a great story. No, anti-matter is sort of a theoretical triumph because it happened actually very similarly to the joke you made earlier or the comment you made earlier about people sort of noticing a gap in the equations.

What happened was Paul Dirac, who was a famous theorist around the beginning of when quantum mechanics was being formed, he was taking the Schrodinger equation, the equation that describes the motion of particles, and he was trying to make it work for really fast-moving particles. He was trying to fold in relativity in quantum mechanics, which famously is very hard to do. But he was able to actually unify quantum mechanics and special relativity, the laws that tell you what happens when things move really, really fast. So he came up with a... In one set of equations.

Yeah, he came up with a new equation. It's called the Dirac equation. And it's like the relativistic version of the Schrodinger. equation. Schrodinger equation tells you what happens for quantum particles that are not moving that fast. The Dirac equation tells you what happens when quantum particles are moving fast enough that relativity kicks in. So he had this awesome equation, already a triumph. Right. And it turned out to be true, right? This theory is as far as you know now, true. Yeah. And that's amazing, right? Dirac unified special relativity and quantum mechanics.

And remember, we've never successfully unified quantum mechanics in general relativity theory about like bending space that's still like to be done so folks out there looking to make a big impact on physics that's been an open problem for 100 years it's TBD to be discovered that's right but then Dirac looked at this equation he's like on this something weird about this equation he noticed that the equation worked for a negatively charged particles like electrons but it would also work for positively charged particles they thought hmm that's interesting did the equations have a pocket or like an empty space for an anti-electron or he just figured out that this equation that we think describes the universe could also work for something

that looks like an anti-electron. Yeah, it's an equation with two solutions, just like you find all the time in equations that have like squares in them, like x squared equals nine. Well, there's a solution there, right? X equals three. But there's another solution, X equals minus three. Right, because minus three times minus three is also plus nine. Yeah, exactly. And so he noticed that His equation described electrons as we know them, but it also described something else, something we hadn't seen before, another particle with positive charge. And it's for exactly that reason that there's a squared in his equation. And it allows for, you know, particles of either charge to satisfy his equations.

And so he predicted that this would work for an anti-electron, but did he predict it for other antimatter particles or just for the anti-electron? Oh, yeah, the story gets exciting. But first, he started small. He's like, you know what? I think this is real. And I wonder, like, what went through his head there? What makes him think, oh, that's not just a mathematical oddity.

I've discovered something about the universe. Because a lot of times we have equations that describe things, and we just sort of toss out solutions and say they're not physical. Like if you're talking about, you know, how a ball moves through the air, you have a parabola. And sometimes there are non-physical solutions to those equations. And you think, oh, those don't make sense because they require the ball to move through the ground or something. But he thought, no, this is real.

It's kind of like if you said that the number of cookies that I have times the number of cookies you have equals nine, you wouldn't say we both have minus three cookies. Precisely. That wouldn't be a serious solution because, let's face it, we always have cookies. Yeah, you impose a physical requirement. There are at least zero cookies, right?

There's no such thing as a negative cookie. But Dirac was like, you know what? What if negative cookies are real? You can count it as a negative cookie. If I eat your cookies, then maybe you have negative cookies. I don't know. I would have a very negative reaction, sure. I think there's probably a whole course in philosophy on theory of negative cookies.

The ethical ramifications of less than zero cookies. Yeah, anti-ethics or anti-pastry. But he predicted it. He was ballsy. He said, I believe in myself. I believe in my equation. I think this thing is real. So he predicted it.

This is 1928. way before iPhones or the internet. Yeah, he couldn't have just Googled for it or asked Siri if this is real. He made a prediction. And he's sort of famous for being a bit of an odd guy. He'd probably fit in well on the Big Bang theory. He had a lot of self-confidence,

but maybe not a lot of social skills. He made the claim that these equations work for an anti-electron, so therefore there must be an anti-electron? Was that his big leap there? That was his big leap. he says, I've discovered this equation and the equation is fundamental to the universe and it describes something happening that we haven't seen. So I think it happens, right?

Even though we haven't seen it because we haven't looked for it, this equation allows for it to happen. So let's go see if it does happen. Was that a shift in physics as well? You know, people thinking that, well, if the math predicts it, then it must be real. You know, like that's a big leap to think about that. It's a big leap. It takes a lot of ego.

But it was the first time. particle had been predicted. Yeah. Before that, every particle discovered had been discovered first and then explained. It's like, huh, look what we found. How does that make sense? Let's try to stitch together a theory that accommodates it. It's like in baseball, it's like

calling your shot rather than just hitting a home run. You're like, I'm going to hit a home run, and it's going to land right over there. Well, I guess he had a history. Maybe up to that point, there was a history where they had discovered particles and then they found out the math fits it. So then in this case, the math

fit it. And so he probably thought, well, then it must exist. Yeah. And it didn't take long for him to be proved right. He was a Babe Ruth of physics. Yeah, and it gets better. So it was just a few years later, a guy at Caltech named Carl Anderson. He actually found the first positron. And like we were talking about, he found it in cosmic rays. He just saw one flying through the air. And what made him think it was a positron or an anti-electron? Was he looking for it? Or I guess maybe his setup could only work for an anti-electron? No, he was looking just to study cosmic rays, which were a fairly new discovery at the time. The whole idea that there were these particles being rained on us from the upper atmosphere was sort of new. And he was using a pretty cool device at the time.

The first cosmic rays were discovered basically by huge cubic blocks of film that they then had to slice up and analyze later. But he wanted some real time. He wanted to see these things in real time. So he used this thing called a cloud chamber, which is basically a box of glass that you can see into. Then you fill it with air, which is super saturated with water. And when a particle goes through it that has a charge, it'll cause droplets along its path. And so what you see are these, like, little drops of water appear as a particle flies through it. You can actually build the cloud chamber in your garage. Yeah, it creates like a trail of bubbles as it goes through. Not bubbles. There's something else called a bubble chamber. This creates a trail of

water droplets. And you can see them. And they have them in a lot of science museums. You can see like muons flying through them. And so he had seen muons and people had seen electrons and stuff like this. But then he put it in a magnetic field. And the magnetic field bends the path of this particle. And a magnetic field will bend a positive particle differently than it bends a negative particle. Cool.

And so this was just a few years after Dirac. So did he know about Dirac's prediction or did he discover it kind of independently? No, he definitely knew about direct's prediction. It was an idea that was out there. So it helped him sort of interpret his data. And what he saw was, of course, a bunch of electrons. Electrons are much more common in the atmosphere than positrons. But then he saw this one track, this track that curved the wrong way.

And he said, ooh, what's that? You know, and he could tell the mass of the particle by how much it curved. And you could tell the charge of it by the direction of its curve. So he knew, for example, it wasn't a proton, because the proton is much heavier and would have curved less. So curve just like an electron. Except the other way. Except the other way. And this is amazing to me because these days to discover something,

you don't just need one example. You can't be like, hey, look, here's the Higgs boson. We found it. And here's the picture of it. You know, we need like 500,000 examples or something to show statistically that it really exists. Really? He claimed this discovery with n equals 1 data points? N equals 1.

It was so conclusive. nothing we knew of could make that data. He didn't even wait to get another one. No, he didn't even wait to get another one. And you can see like that is famous data. You can Google for it and see like his original data that proved the discovery of the Positon. Are you sure? He didn't get at least two?

He didn't wait a little bit and got another one. Maybe he got some backup data. But, you know, that's all he needed. That convinced everybody. I'm still convinced. Wow. By one image. Yeah.

And so he discovered. that was 1932. And then the next year, Dirac wins the Nobel Prize for predicting antimatter. Did Carl Anderson also get it? Or just Dirac? Just Dirac in 1933.

But then Anderson won it three years later, sort of in a combined Nobel Prize for cosmic ray discoveries. But my favorite bit of this story is that Dirac, you know, he was a he he had a heady guy, and he'd made this bold prediction, and then it actually had come true.

So then, you know, he'd like called his shot and like Babe Ruth. So then in his acceptance speech, where he's like, you know, at the Nobel Prize ceremony, getting the Nobel Prize from the King of Sweden, in that speech, he predicts another particle. He, like, doubles down. He's like, I predict a million dollars in my bank account tomorrow. And you see, it's all true. He predicted the antiproton.

He was like, well, if the electron has an antiparticle, why not the proton? So he predicted it. Oh, wow. And then when he got the Nobel Prize for that one, one, did he also make another prediction in the next speech? Like, when did this stop? It's still going on, actually. I see.

He's still making predictions. He's like, and the next election will be won by. Hey, doubling down works for you, right? You just keep doubling down. And exponentially, you get more and more Nobel prizes. Yeah. All right, cool. So that's how the anti-matter, the first antimatter particle was discovered.

And since then, we've seen antimatter. particles all over the place and for all kinds of particles too, right? That's right. And these days in particle collisions, we can very easily make anti-electrons, which are positrons, and anti-mewons, and we've seen anti-corks and all sorts of crazy stuff. There are some anti-particles we haven't seen yet. Oh, really? They're still hiding or we just haven't bothered?

Well, no, there's some that are still hiding. For example, anti-nutrinos. Like we know neutrinos are a thing. What we don't know is if there are anti-nutrinos. I mean, we talk about it, but we don't really know if anti-nutrinos are just the same thing as neutrinos because they have no electric charge. Yeah.

How can you be anti-nothing? Yeah, well, for example, the photon is its own antiparticle. Or you could say it doesn't have an antiparticle. So we don't know if neutrinos are in that category of particles that don't have antiparticles or if they're in the category of particles like electrons that do have antiparticles. It's a deep mystery.

It's like asking who is the anti-version of Switzerland, and Switzerland is neutral, so nobody and everybody. Precisely. So people are trying to figure out, do neutrinos have antiparticles, or are they just themselves, all sorts of stuff? And then people are doing more and more experiments to make antimatter and try to study its chemical properties. We'd love to see, like, more than just anti-hydrogen. We'd love to see, you know, anti-water and all sorts of crazy stuff. But I guess the point is that it does exist and that it is something that was predicted by the physics, by the equations first, and then we went out and found it. And now there's incontrovertible proof that it does exist, that antimatter can exist, does exist, even if we don't know exactly where it is in the universe.

That's right. Even though it's been featured in a Dan Brown novel, it is really out there. And it's a triumph really of theoretical physics to sort of notice these patterns. in the universe and assume that the universe might follow those patterns, right? To say we think the universe makes sense and if we can figure out the rules that describe it, then maybe we can use that to predict things in the universe we've never even seen. What a crazy step forward. Yep, it's not a conspiracy theory.

It's a conspiracy fact. I have a picture of it from 1933 that says that it's true, so it must be true. It's out there. It's in you. me, it's in Jorge's bananas. So get used to it, folks. All right. Well, we hope you enjoyed that and got to learn a little bit more about the anti-universe out there. The anti-history of physics, or the physics of anti-history, or the history of antifysics. Well, you've definitely convinced me, Daniel. I am definitely pro-antimatter now. Thanks, everyone, for tuning in.

have a question after listening to all these explanations, please drop us a line. We'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge, that's one word, or email us at Feedback at danielandhorpe.com. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed.

There's been a bombing at the TWA terminal, just a chaotic, chaotic scene. In its wake, a new kind of energy. Emerge. Terrorism. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

Why are TSA rules so confusing? You got a hood of you. I'll take it off. I'm Manny. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that. Why are you screaming at me? I can't expect what to dude. Now, if the rule was the same, go off on me. I deserve it. You know, lock him up.

Listen to No Such Thing on the IHeartRadio app, Apple Podcasts, or wherever you get your podcast. No such thing. I'm Dr. Joy Hardin Bradford, host of the Therapy for Black Girls podcast. I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Nielbornet and I discuss flight anxiety. What is not a norm is to allow it to prevent you from doing the things that you want to do, the things that you were meant to do. Listen to therapy for black girls on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. This is an IHeart podcast.