The battle between matter and antimatter

At the beginning of our universe, in addition to matter, there was also an equal amount of antimatter, matter's opposite. But today, there's lots more matter than antimatter. So how did that happen? Well, the answer might have to do with neutrinos, a very mysterious, elusive particle. They're incredibly difficult to catch and study because they don't really interact with anything. But a group of scientists is now betting that one specific, hypothetical type of neutrino might have played a very important role in getting matter to win the war against antimatter. Today, we go galaxy brain and delight in getting to spend a little time pondering this hypothetical, long ignored particle. Support public media with NPR+ and enjoy perks for over 25 podcasts like this one. This show’s perks include sponsor-free listening. Learn more at plus.npr.org http://plus.npr.org/. See pcm.adswizz.com https://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 https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:00Speaker 00

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• 0:20Regina Barber?

  Hey, everyone. Regina Barber here, and it's time for my favorite time of the month, our space news segment, Spacing Out. And I'm, of course, here with Scott Detrow, All Things Considered host, co-mastermind of the series. Welcome back to the show, Scott.

• 0:36Speaker 02

  Throughout the space, it's been too long since we spaced out.

• 0:38Regina Barber?

  It's been too long.

• 0:39Speaker 02

  We're fixing it right now.

• 0:40Regina Barber?

  And this time, I roped in our colleague Ari Daniel again to hang with us. Hey, Ari.

• 0:45Speaker 03

  Hi.

• 0:46Speaker 02

  Ari, you're a three-time guest on the show now. You are like, if this were a Star Trek series, you're going from like guest star to like series regular. Congratulations.

• 0:54Speaker 03

  I can't be shot by a phaser now.

• 0:56Speaker 02

  That's what I was gonna say. It gives you better odds on an algorithm.

• 0:59Speaker 03

  I'm no longer an extra.

• 1:01Regina Barber?

  OK, and in this episode, I want to ease you both back in with a little tale about the early universe.

• 1:12Speaker 02

  We going way back to the original, to the Big Bang?

• 1:15Regina Barber?

  We're going way back, all the way back. The Big Bang, the beginning of all of our reality, the time where our universe was smushed into a tiny, small space, which was basically a hot, dense, primordial goo.

• 1:32Regina Barber?

  I'm talking about things being so hot that even atoms didn't exist. It was basically just energy, like light and subatomic particles that make up matter we see today, like protons or electrons.

• 1:45Speaker 02

  Always an interesting topic, but why particularly are we talking about this hot, dense, ancient soup today?

• 1:52Regina Barber?

  Yeah, because that's where our first story is going. Some theoretical physicists are adding more detail to the story of why there's matter around all of us, that battle between matter and antimatter, where the winner was decided within a millisecond of the universe's age.

• 2:07Speaker 02

  I didn't realize that that was such a quick resolution to that. I mean, the flash versus the anti-flash

• 2:12Regina Barber?

  Yeah, exactly.

• 2:13Speaker 02

  really draws out compared to matter/antimatter.

• 2:15Regina Barber?

  No, it all of these wars, everything we're talking about, milliseconds, like

• 2:19Speaker 03

  Versus the wars on Earth.

• 2:20Regina Barber?

  Yes.

• 2:21Speaker 03

  For our next story, we're going to talk about a telescope that was damaged in the war between Russia and Ukraine and the effort to restore it.

• 2:32Regina Barber?

  Today on the show, relax, unplug, set aside time to ponder how we got here and how some scientists are taking back control of their future. You're listening to Short Wave, the science podcast from NPR.

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• 4:07Regina Barber?

  OK, Scott, all right. I think it's only fitting that we start at the beginning of time.

• 4:11Speaker 03

  Natural.

• 4:12Speaker 02

  So let's get into it. You have set me up with a high bar of making relatable conversation about particle physics.

• 4:19Regina Barber?

  I tried so hard. It's hard for me, too. I'm a physicist, but like particle physics has always been hard. The particle at the heart of this story is a hypothetical particle, one that might have affected all of matter in the universe at the very beginning of existence. It's a kind of neutrino.

• 4:35Speaker 02

  Let's just say theoretically, I don't remember what a neutrino is.

• 4:38Regina Barber?

  Yeah.

• 4:38Speaker 03

  Well, theoretically, I have an answer. Neutrinos are extremely small, mysterious particles that don't really interact with anything, so they're incredibly difficult to catch and study. But we do know that they come in three flavors, and there are roughly 100 trillion of them passing through each of us every second.

• 4:57Speaker 02

  Wait, what?

• 4:57Regina Barber?

  Yeah.

• 4:58Speaker 02

  That's crazy.

• 4:59Regina Barber?

  Yeah.

• 4:59Speaker 03

  Yeah.

• 5:00Speaker 02

  What do they have to do with the early universe?

• 5:02Regina Barber?

  So when the universe was created over 13 billion years ago, matter and matter's opposite, called antimatter, were thought to exist in equal amounts. But when matter and antimatter interact, they annihilate each other.

• 5:14Speaker 02

  So how did we get to the place where we are now, where you and I and the microphone and everything else are made of matter?

• 5:20Speaker 03

  We don't have time to get into this in too much depth, but what you need to know is that there's this idea that at the start of the universe, neutrinos could have been created in three pairs. And each one of those pairs has a heavy right-handed neutrino and a lighter, left-handed neutrino.

• 5:38Regina Barber?

  Yeah, so some models account for matter overtaking antimatter by assuming that these like heavy right-handed neutrinos, they decayed over time, and they decayed into matter more than they decayed into antimatter. And this created this imbalance in the early universe. So they don't exist anymore. There are no right-handed neutrinos. But in this framework, historically, physicists have treated one of those right-handed neutrinos, those heavy ones, as irrelevant.

• 6:02Speaker 04

  Generally, in the literature, this effect of third right-handed neutrino is ignored. But we found it to be very fascinating, and it was affecting so many things.

• 6:11Regina Barber?

  So that's Rishav Roshan, a theoretical particle physicist at the University of Southampton in the UK. He co-authored a recent study that suggested finally taking into account this last heavy right-handed neutrino would affect things. He and his co-author Sudipta Sow at the Indian Institute of Technology Kampur found that taking this into account makes the universe evolve slightly differently, suggesting that matter could have dominated the universe sooner than previously thought.

• 6:41Speaker 02

  I'm just like, there's a lot of big-picture stuff to process, which is why I like talking about space.

• 6:45Regina Barber?

  Yeah.

• 6:46Speaker 02

  Because it's just like, the scale of the conversation is mind-blowing.

• 6:48Regina Barber?

  It's so big.

• 6:49Speaker 02

  And you just have to move forward sometimes.

• 6:50Regina Barber?

  You do.

• 6:50Speaker 02

  So I'm gonna try to do that. I have asked variations of this question before, but this is a hypothetical particle?

• 6:56Regina Barber?

  Yeah.

• 6:56Speaker 02

  How do you do real-world tests, then?

• 6:58Speaker 03

  Yeah, so we talked to Brian Ramsen, who's an experimental neutrino physicist at Fermilab about this exact question. He didn't work on the paper, but he said you basically can't study it directly at all.

• 7:10Speaker 05

  Direct observation is so heavy that I do not know how you would produce it with the current technology. I don't even know how you would produce it with future technology.

• 7:19Regina Barber?

  OK, hope is not lost, though. So Rishav thinks signatures of this heavy right-handed neutrino could be found indirectly one day by studying other cosmic phenomena, in one case, using a space observatory that'll be going up soon, like in 2035.

• 7:32Speaker 02

  Interesting. I will bookmark to talk about that space observatory.

• 7:35Regina Barber?

  Yeah.

• 7:35Speaker 02

  A little closer to then.

• 7:36Regina Barber?

  More particle physics.

• 7:37Speaker 02

  In the meantime, let's talk about an observatory here on Earth, this radio telescope in Ukraine.

• 7:42Speaker 03

  Yes, so it's called the Ukrainian T-shaped Radio Telescope Model 2.

• 7:47Regina Barber?

  UTR-2 for short.

• 7:49Speaker 03

  That's right. And it's at the Institute of Radio Astronomy of the National Academy of Science of Ukraine, where Vyacheslav Zaharenko is the director.

• 7:59Speaker 04

  Is the largest decimeter radio telescope in the world.

• 8:04Speaker 02

  Is that decimeter?

• 8:05Speaker 03

  Yes, the decimeter, which is 10 meters or about 33 feet. And that means that this telescope is capable of observing low-frequency radio waves, the lowest of any large telescope. When it was built in the 1970s, it was the biggest of its kind.

• 8:20Regina Barber?

  So astronomers use UTR-2 to study the bursts of radio waves that are emitted by certain planets like Jupiter and other celestial bodies.

• 8:29Speaker 03

  The telescope was also able to detect lightning on Saturn. And when they pair it with radio telescopes elsewhere in Ukraine, they get an array the size of the country that can make higher-resolution observations.

• 8:40Speaker 02

  I mean, that sounds so powerful, but it seems like so many other things in Ukraine, it's been damaged during the war?

• 8:45Speaker 03

  Yes, heavily, Scott. The telescope is part of an observatory near the Russian border that's made up of a bunch of buildings. Vyacheslav says that Russian forces occupied the area for more than six months at the start of the war in early 2022.

• 9:00Speaker 04

  And practically, all these buildings were seriously damaged, two fully destroyed. All computers were stolen.

• 9:09Regina Barber?

  The radio antennas were largely untouched, fortunately, but there are these three underground tunnels, each one roughly half a mile long, and the northern one?

• 9:19Speaker 04

  Our enemy used this tunnel for training.

• 9:23Regina Barber?

  It's become a shooting gallery, says Vyacheslav.

• 9:26Speaker 04

  Like war base.

• 9:28Speaker 03

  Plus, Vyacheslav says there are still active mines. So even after the Russian forces left in the fall of 2022, it hasn't been safe for the researchers to return to work there.

• 9:39Speaker 02

  I mean, that's a complicated challenge. What have Vyacheslav and his colleagues been doing in the meantime?

• 9:44Speaker 03

  They've been plotting a massive upgrade of the telescope, actually, using what's happened as an opportunity to modernize the entire system.

• 9:52Speaker 04

  We not need wait for end of war. We start now.

• 9:57Regina Barber?

  So they can't do any of the installation until there's a ceasefire or some other type of agreement, but they can spec things out and build and test the components they need. It helps that the antennas are still in pretty good shape.

• 10:08Speaker 02

  What is the goal of this upgrade? What will it achieve?

• 10:12Speaker 03

  Well, the researchers want to expand the radio wavelengths they're able to observe, which would allow them to, among other things, try to look for gas from the early universe. The updated telescope will also be able to peer at different parts of the sky simultaneously. Plus, all of the equipment will be better shielded from the elements.

• 10:29Regina Barber?

  Yeah, we spoke with Michel Teger, who's a theorist astronomer, and he works at the French radio telescope called Nanoufar. He says that the Ukrainian telescope is important for the international astronomy community, too.

• 10:41Speaker 06

  Well, I hope they can rebuild the projects we had with them. And that means having an instrument they can have their hands on, and we hope to see it running again.

• 10:52Speaker 03

  Vyacheslav says that despite everything he and his colleagues have endured these last several years, he believes this upgrade is possible.

• 10:59Speaker 04

  Oh, I am an optimist. We need to build new telescope and install as end of this story.

• 11:12Speaker 02

  I love that resolution and optimism.

• 11:14Regina Barber?

  Yeah, me, too.

• 11:21Regina Barber?

  Scott, Ari, thank you so much for coming on the show to space out with me. I love it every single time we do it. It's always a pleasure.

• 11:29Speaker 02

  Thank you. I really, I really hope they get that telescope built again.

• 11:32Regina Barber?

  Me too.

• 11:33Speaker 03

  Thanks so much, Regina. It was a pleasure to be with you.

• 11:39Regina Barber?

  If you liked this episode, share it with a friend. It really helps our show. And hey, why don't you also give us a follow on the NPR app or wherever you're listening from, so you'll never miss a new episode.

• 11:52Regina Barber?

  This episode was produced by Hannah Chin and Elena Burnett. It was edited by showrunner Rebecca Ramirez and by Jeanette Woods. Tyler Jones checked the facts. Ewan Fain was the audio engineer. Special thanks to Chonda Prescott Weinstein. I'm Regina Barber. Thank you for listening to Short Wave from NPR.

• 12:28Regina Barber?

  I also hope that I understand particle physics eventually, one day.

• 12:32Speaker 03

  Don't we all?

• 12:33Regina Barber?

  Yeah.

• 12:34Speaker 00

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