Short Wave - Creating Antimatter: Matter's "Evil Twin"

Episode Date: March 9, 2020

Physicists have done the math and there should be as much antimatter as matter — but that hasn't been the case so far. NPR Correspondent Geoff Brumfiel explains what's up with matter's "evil twin," antimatter.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey everybody, Emily Kwong here, sometimes host of our fine podcast. And today I've got science correspondent Jeff Brumfield in to discuss antimatter. Yes, antimatter. Anti-matter. I'm so excited to talk to you about antimatter. And Emily, I know exactly what you're thinking. The anti-matter pods are rigged to blow up the moment we go into what drive.

Star Trek, right? I mean, antimatter is a huge part of Star Trek. All right. I know the Vulcan salute, live long and prosper. That's about the extent of my knowledge of Star Trek. But I get your point. Antimatter does kind of sound like science fiction. But it's real.

That's the cool thing. Yes. Antimatter particles are these strange mirror particles to the stuff we see all around us. And scientists have made it using a giant particle accelerator in Europe. They're studying it because they hope it can answer some fundamental questions about the universe. Okay. Not entirely sure I get it, but by the end of the episode, I assume we all will. So today on the show.

Antimatter. What it is, how it works, and why one scientist has spent decades trying to trap it. Jeff, I have a lot of questions about antimatter. But can you just start with regular matter? What is that? Yeah, so a refresher for those of us who don't remember. Regular matter, it's a broad category for everything. So your matter, I matter, the studios matter, the microphones matter.

I get it. It's matter and we matter. We do matter. It's a nice thought. Yeah. And as matter, we're all made of atoms. So you're a bunch of atoms in the shape of an Emily Kwong and I'm a bunch of Adams in the shape of a Jeff Brumfield. Got it. Now, for antimatter, I'm actually going to let another Jeffrey, who knows a lot more physics than I do answer this one. His name is Jeffrey Hanks and he's a researcher at Our House University in Denmark. Antimatter, I think of it as kind of an evil twin of the stuff that makes up our everyday world. Intriguing, go on. It is. It is. It's just this kind of opposite matter. It's like this mirror to everything that's around us. So antimatter, it's here right now. Yeah, I mean, it's a little more complicated than that, but antimatter is real stuff, and it exists in our universe.

And actually, before anyone ever even detected it, they predicted it because math. The equations of physics demanded. In fact, it was discovered that way, you know, by coming up with an equation that predicted its existence when nobody was really looking for it. And I am not going to attempt to describe the fundamental equations of physics on this podcast because I don't really understand them. But Hank says the closest analogy he's got for us mortals to think about is this math problem. What's the square root of four? Two. Very good.

But there's a second solution. Negative two. Right? Because negative two times negative two is four. So the way you just went straight to two, that's exactly kind of what happened in physics. Like there were these equations and there was a positive set of solutions for particles and a negative set. And everyone was like the negative set. What does that even mean?

nonsense. But it turned out there were these negative particles. They did exist and they're called antimatter. Oh. Okay. So there was this theoretical idea of antimatter kicking around for a while, which kind of explains what it is, but what is it exactly? Here's the thing. It really is like opposite matter. So protons, do you remember protons? Yeah. They're positively charged subatomic particles. They are. Antiprotons are negatively charged. Electrons. They're negatively charged. And their antiparticles are positively charged. Okay, this is kind of amazing.

It is kind of amazing. And here's the best part. It actually lives up to the sci-fi analogy. So just go with your vestigial sci-fi brain. And I get it. Emily, you're more of like Colin Firth, Pride and Prejudice, BBC, you know. There's no shame in it. There isn't.

There isn't. I've seen it probably more times that you have in my life. But what do you think happens when matter and antimatter get together, when they actually meet. Okay, if Antimatter is the evil twin, they fight. They duel. They duel. Like in a Jane Austin novel, they duel. Well, you're not too far off, but I'm going to let the actual experts explain it to you. Fine. Matter and antimatter have a tendency to cancel each other out. Wait a minute. Where is this quote? Precisely. Under certain conditions. When two identical particles of matter and antimatter meet. These are your experts, Jeff? Captain Kirk.

And is that Leonard Nimoy as... Annihilation, Jim. Yes. Total, complete, absolute annihilation. As Spock? It is. That's right. And you're right. That's Star Trek Season 1, Episode 27, original track, the best track.

But here's the thing, Emily. It's actually 100% accurate or pretty close. So the universe won't end if antimatter and matter meet, but the two particles do disappear in a flash of life. light. The antimatter can't exist in the presence of matter. That's where the science fiction stuff comes in. These things really do annihilate each other if you get them together. Okay, so I've covered a lot of physics over the years, and this is pretty much the only case where the sci-fi and the reality match, although I will say annihilation is actually a lot less sexy in real life. It's really

just annoying to have to deal with something that you have to make and that the universe is trying to destroy at every turning point. Sounds hard to be an antimatter physicist. It is. I mean, he's literally been doing this since the 90s, and like he does get a little frustrated. All right. You said earlier that antimatter, it's here in this universe, but this universe is full of matter, and I don't see any antimatter lurking around.

So where is it if it's exist in theory, but it's hard to find in reality? I don't get this. You know, who else doesn't get it? Every physicist on Earth. Like, this is one of the fundamental questions. The equations say there should be as much antimatter as there is matter, but in practice, antimatter is actually super hard to find. And Hank says nobody knows why. There aren't any good ideas about this. I mean, physicists do see little bits of antimatter here and there. In fact, anti-electrons were first discovered in cosmic radio. coming from deep space way back in the 1930s.

And actually, I've got another natural source of antimatter right here in the studio, Emily. In this room? Yes. You ready? Yes. This banana. What are you talking about? Is this an real episode? Is this an episode about nothing and tomfoolery?

Can I hold the banana to make sure it's real? I'll explain. Yes. Okay. So obviously the banana is not antimatter. It's a banana. It's matter. But here's the thing about bananas.

Bananas are full of potassium, which is really good for you. But there's also a radioactive isotope of potassium in a banana called potassium 40. This is a naturally occurring isotope. So some portion of the potassium in the banana is potassium 40. Now, here's the thing. Potassium 40, when it decays, it usually releases an electron. but very, very, very, very rarely. It releases an anti-electron.

So if we just hold this banana and wait. For how long are we waiting? Okay. We'd have to wait 75 minutes. We're a 10-minute podcast, Jeff. We can't just sit here for 75 minutes. What I'm hearing is seven-part series on antimatter, Emily Kwan. And a meditation in silence.

That's right. No, so on average, this entire banana will spit out. one anti-electron every 75 minutes. I think this really makes the point well, right? Like, anti-matter exists. It's not some parallel universe. But one tiny anti-electron from trillions of banana atoms is like even that's a pretty rare thing to have happen.

And Jeffrey Hanks wants a lot more than that. That's why he's at this giant particle accelerator at CERN in Switzerland. Okay. So tell me what he's up to there. Well, Hanks wants lots of anti-electrons. and, and this is key, anti-protons. Okay. So it turns out the anti-electrons are kind of easy.

You can find other radioactive sources besides bananas that can make a lot more of them. And then the accelerator makes anti-protons. And here's the thing. So you have to very carefully, Hank's test, to bring the antiprotons and the anti-electrons together. We call it smurge. It's a smooth merge. Smurge. Smurge.

But even after that, smurge, they still end up with a lot of antimatter just disappearing. 30 million antiprotons that's converted to 100,000 or so trapped antiprotons. Of those will get 20 or 30 that actually make antihidrogen that we can use. Whoa, whoa, whoa, whoa, whoa. Antihrogen? Is that what I just heard, Jeff? What is that? Antihigrogen is just one anti-electron orbiting one anti-proton.

And it's the antimatter equivalent of the lightest element on Earth, so that's regular hydrogen. So he's willing to go to all this trouble just to get a few atoms of anti-hydrogen. But why go through all the trouble, you know, of making anti-hydrogen? Okay, so here's the thing. He's hoping to get some clues from anti-hydrogen about matter and antimatter. And the thinking goes like this. hydrogen is the lightest element in the universe and... Hydrogen is probably the thing we know best.

We've been studying it forever. We really understand it. So by looking very, very carefully at anti-hydrogen, he's hoping that they can learn more about what's going on with antimatter. And that's basically what he's doing. He's using lasers and all kinds of stuff to probe this anti-hydrogen to see how it behaves. Well, has it shed any light on where the rest of the antimatter is? Not yet, not yet.

So his latest results were just published, which is why we're talking today. And so far, anti-hydrogen is behaving exactly as predicted by all those fundamental physics equations. And so far, with the places that we've looked and to the precision with which we've looked, they're the same. And that's kind of a problem because the equations also say there should be as much matter as antimatter. So unless they can find some sort of deviation, it may not be possible to figure. out, you know, where the antimatter went. So we don't have any clues, but that's okay because he's just getting started. This is really early days.

There's lots more questions to answer, including, and think about this one, Emily. Matter falls down. What does antimatter do, fall up or down? This entire story feels like opposite day. Fascinating. Well, Jeff, there's so much more to learn about antimatter clearly and so much more Star Trek. To watch, I'm converted. Excellent. Live long and prosper, Emily.

You've been listening to Shortwave from NPR. Today's episode was produced by Rebecca Ramirez, edited by Viet Le and fact-checked by Emily Vaughn. We had engineering help from Stacey Abbott. I'm Emily Kwong. See you next time. I've been with this field through its entire evolution. So if there's one thing you could tell the average human about antimatter, what would it be? Stay away from it and do something else with your life.