Science Friday - High Energy Cosmic Ray Detected | These Penguins Are The Masters Of Microsleeping

Episode Date: December 18, 2023

Scientists Report Second Highest-Energy Cosmic Ray Ever DetectedAround 30 years ago, scientists in Utah were monitoring the skies for cosmic rays when they detected a surprising particle. It struck the atmosphere with much more energy than they had previously seen—enough energy to cause the researchers to dub it the “Oh My God Particle.”Over the years, a collaboration of researchers in Utah and Japan has detected other powerful rays—about 30 a year—but none that rival the OMG. In 2021, however, a second particle was detected. It was only slightly less powerful than OMG, but still many times more powerful than can be created on Earth. That 2021 particle was named “Amaterasu,” after a sun goddess from the Japanese Shinto religion. The researchers described their observations in a recent issue of the journal Science.The researchers believe the particle must have come from relatively nearby, cosmically speaking, as otherwise it would likely have collided with something in space and lost its energy. However, when they tried to trace the particle back to its origin in space, they were unsuccessful. Both the OMG particle and the new Amaterasu particle seem to have come from empty regions of space, with no violent events or massive structures to create them.Dr. John Matthews, a research professor in physics and astronomy and manager of the Cosmic Ray Physics Program at the University of Utah, joins Ira to talk about cosmic rays, how they’re detected, and the challenges of finding the origin of particles like Amaterasu.These Penguins Are The Masters Of MicrosleepingDo you know that feeling when you’re just so tired that your head starts to droop? Your eyes feel heavy? And you drift off for just a moment … before snapping back to alertness, wondering what just happened.Sleep comes in a variety of snoozes and sizes. We humans are not going to get a full night’s rest by nodding off here and there, but that’s pretty much what some chinstrap penguins do: They doze off more than 10,000 times a day, for just a few seconds at a time. And when you do the math, it can add up to 11 hours of sleep each day, according to a recent study in the journal Science.Ira talks with study author Dr. Paul-Antoine Libourel, a sleep biologist at the Neurosciences Research Center of Lyon in France, about how the penguins do this and the advantages of microsleeps.Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Imagine you're a chinstrap penguin and you are in dire need of a nap. But at what cost? So there is a trade-off between being awake and vigilant and being sleeping and having the benefit of sleep. It's Monday, December 18th, and oh, would you look at that? It's Science Friday. I'm SciFri producer Russia Auredi and we've got a double feature for you today. A bit later, we'll dive into the strange sleeping habits of chin strap penguin. who take thousands of naps a day.

Must be nice. But before we get there, straight out of a sci-fi flick, how researchers are trying to make sense of a mysterious cosmic ray. Have you ever heard of the Oh My God particle? Me neither. But physicists love to give subatomic particles cool names. And back in 1992, when they discovered the highest energy cosmic ray ever discovered, they christened it as the oh my God particle.

because it was really powerful and really mysterious. They had no explanation for it. Hence, OMG. Fast forward to around two years ago, sensors in Utah desert detect the arrival of a second very high-energy cosmic ray, the second most powerful they've ever seen. And while the researchers are convinced that the cosmic ray was real, many aspects of the event don't really make sense. It's more powerful than anything we can make on Earth. and seems to come from nowhere in the sky. The researchers recently described their observations in the journal Science.

Joining me now to talk about the find is one of the co-authors of that report. Dr. John Matthews, research professor in physics and astronomy, manager of the Cosmic Ray Physics Program at the University of Utah in Salt Lake City. Welcome to Science Friday. Hello. Good to be here. Thanks for having me. This new cosmic

reaffind, would it be the oh my God dot two of particles? Yeah, that's one way to describe it. The oh my God particle, you know, somebody was looking at an event to say and said, oh my God, what was that? In this case, we found it a little bit later because of the different kind of detectors that were observing it. And people said,

wow, that's really an impressive energy. That needs an aid. Let's start with the basics. What is a cosmic ray and where does it come from, all those kinds of things? So a cosmic ray is a particle from space. Some can come from within the galaxy, some from outside the galaxy. They can be photons of particles alike. They can be electrons.

At this energy, they're often subatomic particles like a proton. They could be a helium nucleus. In this case, we think it's a proton probably. And how do you detect them? What does your detector look like? Particles at this energy, they're relatively rare. So sort of one particle per square kilometer per century, so really rare. Wow.

Wow. So you detect them in an indirect way. The particle comes in from space. It collides with the nucleus of an atom high up in the atmosphere. It smashes apart that nucleus and you get a bunch of secondary particles. They travel a short distance and do the same thing. And you get what's called an extensive air shower. So you sprinkle the desert with detectors that are about the size of a ping pong table.

And when those charged particles reach the earth surface, they pass through those detectors and generate light, which are detectors measure, and then that's a sample of how many charged particles passed. So around two years ago, you detected this unusual particle. How unusual was it? Well, it's so unusual that 30 years later, it's the second one in this energy range. At low energies, we're seeing them several a night or more,

depending on the energy range. At high energies, they're really, really rare. At low energies, two are passing through your head every second. But at these high energies, you know, it's one per square kilometer per century. So it's really a rare event. When we say that they're powerful, though, when you talk about how powerful this is, what kind of power are we talking about? This event comes in with an energy of like 40 joules.

This particle, if you read the paper, is 244 EEV, X-E-V-E-V-E-E-V, which that is really not a relatable term. But if you say 40 joules, then what that means for an ordinary object is like a 4-kilogram object dropped from one meter on Earth. So if 10-pound object dropped it on the floor, it's that much energy. but instead of being in a brick or something, that's all contained in a single proton. So you're saying if you hold a brick at waist height and drop it on your foot, that's what you'd be feeling. That's what you'd be feeling if you absorbed all of that energy from that particle. Wow, then that's all packed into one tiny subatomic particle. Exactly, which is a pretty amazing amount of energy.

It's millions of times more energy than we can generate. in protons here at Earth, for example, at the Large Hadron Collider. No kidding. And one of the mysteries about this is that it's coming from, as I said, nowhere. Yeah, exactly. That's one of the real mysteries is in the last 20-ish years since 2008, when we've been operating the telescope array, we've detected 30 particles that are in not too much farther from this, but above 10 to the 20th electron volts.

And they all appear to come from nowhere. And in specific, these really, really high ones, high energy ones that come from the Great Void next to us or the Oh My God particle comes from someplace else. None of them really looks like they come from any place you might expect. Do we know what produced them then? Obviously not if we don't know where they came from. That's the mystery, and that's why we have experiments like the telescope array and the Pierre-Oge experiment in Argentina, because people would really love to know where these things are coming through.

But so far, we're not able to really identify the sources. Any conjecture? Anybody have any bets going on or what it might be? Well, the conjectures are things like what's called enacting. galactic nuclei, which is a big supermassive black hole with stuff swirling around it and really energetic jets of particles shooting out of it, stuff that didn't quite get sucked in. That's one possibility. More fanciful ideas are things like, well, maybe it's a decay of a dark matter particle that nobody can see and it decays and then shoots out these really energetic particles.

if it was something like that, that might explain why it's coming from nowhere or everywhere. Could it also mean that we need new physics to talk about this? If it was dark matter decays, we would need new physics, and we would need to be able to find something like dark matter. And that's something people are really looking hard to find, but so far have been unsuccessful. So this really must be keeping physicists up late at night or scratching their heads? Exactly. Well, we're up late at night all the time because that's the nature of our business.

How far away are these possible? I mean, can you determine if you don't know where they're coming from? Can you determine how far away that nothing is? So that's a big part of the mystery. They should come from someplace, quote, unquote, close, because otherwise they'd collide with the microwave background and then they would lose their energy. So what do you have to do to figure this out? I mean, what do you, do you need new equipment? Do you need new theories? We need new equipment and more data.

So new equipment in the sense that it'd be nice to have bigger detectors. Right now, the telescope array is about a thousand square kilometers. We'd like to finish our expansion to 3,000 square kilometers, which is like the size of Rhode Island. Ideally, it would be nice to have muon detectors, but those would be really expensive. So really the answer is more, bigger, better detectors. People talk about putting detectors out in space that would do similar things. There are other groups, right, with detectors looking at different areas? Well, the other main group at the moment is the Pierre-Rouge project, which is down in Argentina, sort of in a space that's very similar to our space in Delta, Utah. There's other groups

like Yuso, the Extreme Universe Space Observatory or Poemma, which would launch satellites up into space or put detectors on the space station and try to find events that way. Do all the groups around the world that are looking for the particles, are they seeing the same ones or the same amounts? That's actually a good question because if you look at what we see here in Utah, you can see the spectrum or the flux of how these things arrive at different energies as a function of time. And in Argentina, they look and they see something very similar. However, when you look at the details at the very highest energies, the Pierre-Oge

experiment sees an energy cutoff that's at a significantly lower energy than what we're seeing at telescope array. So we've been looking and looking for a reason for that, and so far we haven't been able to explain it. But one explanation is there's just different sources in the northern hemisphere than in the southern hemisphere. In the southern hemisphere, they're looking more at the center of the galaxy. see it. And here in the northern hemisphere, we're looking more away from the galactic center.

I get it. Are there any theories about what these could be where they're coming from that could be tested to see if they're correct or not? Well, the test is, can you point it back to some object? And at a little bit of lower energies, we're starting to see hints of some things, but not at these really high energies. And is that frustrating or fun? Oh, it's both frustrating and fun. It's frustrating in the sense you'd really like to find the sources of these events. And, you know, that would be very fulfilling if we could really nail down what these

things would be. On the other hand, there's a lot of mystery and fun in the chase. And you keep working at it and trying to find new and better ways to figure out. what these things are and where they're coming through. Well, you're not the first physicist who said that the chase is more fun than the actual discovery. Well, you've got to be an optimist when you're in this kind of business. Well, we'll be checking back in with you when you get some new stuff. Is that okay? Oh, that would be great. Thank you very much.

We have run out of time, Dr. Matthews. Dr. John Matthews is a research professor in physics and astronomy, manager of the Cosmic Ray Physics Program at the University of Utah in Salt Lake City. Thank you for taking time to be with us today. Oh, thanks for having me. This has been great. You know that feeling when you're just so tired that your head starts to droop,

your eyes feel heavy, and you drift off for just a moment before you snap back into alertness, wondering what in the world just happened? You know, sleep comes in a variety of snoozes and sizes We humans are not going to get a full night's rest by nodding off here and there, but that's pretty much what chin-strapped penguins do. They doze off more than 10,000 times a day for just a few seconds at a time.

And when you do the math, it adds up to an easy, breezy 11 hours of sleep each day. So why do they do this and how? These are findings from a new study in the journal Science, and joining me as one of the authors, Dr. Paul Antoine Lieberle, sleep biologist at the Neurosciences Research Center of Leone in France. Welcome to Science Friday. Hi. Yeah, thank you. Hi there.

Tell me what's happening in the penguin's brains. Are they getting that full REM sleep like we get? So we have recorded the penguin brain indeed, and we have recorded their brain activity for several hours, several days, actually, even days. And we have been able to detect the classical two type of sleepstores. that we found in mammals and birds. Slow wave sleep and rapid eye movement sleep.

Slow wave sleep occurs in the penguin briefly, and REM sleep also occurs in very short boots, lags in other birds. What was the most interesting things in the penguin was the duration of their sleep, actually. You say, yeah, durations, just for how many seconds at a time? Their slow wave sleep duration is four seconds in mean.

They get 75% of their sleep quantity with boots that last 10 seconds maximum. Wow, an average of only four seconds per nap. Now, why would they do that? This is a big and interesting question. We know that there is several pressure on sleep because when animals are sleeping, they are not aware of their environment. They have a decrease in their vigilance. And then it's not really good for parental care, for having active behavior.

So there is a trade-off between being awake and vigilant and being sleeping and having the benefit of sleep, but with a decrease in the vigilant. So we think that this is a way that the evolution find to help the penguin to remain vigilant and sleeping at the same time. Because the penguins are vigilant over their eggs while they stand up, aren't they? And they're in their chicks. This is what we think.

And we also observe the correlation with the very fast eye closure. So they open the eye, they close the eyes, sometimes from round side, two eyes at the same times or only one eyes. We think that this fast change of brain states, sleep and wake, is a way to cut the level of vigilant. This is Science Friday from WNYC Studios. And how do the chin-strap penguins go about their day if they're constantly sleeping and waking and falling asleep? They are not doing many things. Their day when they are incubating is almost sleeping and watching around, I would say. Sometimes there is some active wake when the partner is coming back from the sea.

We can observe some covenship behavior. Sometimes they are rearranging their nest. But basically, the penguin, while they're incubating, they are switching very fast between wake and sleep. And this is what is very interesting here. That is interesting because I'm wondering about, we know what wonderful swimmers they are. What about when they're in the ocean?

How can they be sleeping then? That's a great question. This is the other part of a study, because we have been able to record 11 days continuously, we have recorded also the brain activity when the penguin were diving, when they are swimming, and we found several periods of time, not very long, but several periods of time

while the penguin were remaining resting at the surface of the sea, floating, and we found during this period some brain signature that are typical of sleep. Then we can extrapolate that, the penguin were able to sleep at sea, even if it's not clear about how long are they sleeping and whether their sleep is as fragmented as when they are on land. How different is the tin strap penguin sleep from how other birds or critters sleep?

Is there anything similar? There are many birds where their sleep were recorded. And basically, the brain signature, it's quite the same. There is slow wave sleep, rapid eye movement sleep, and there is also unilateral. lateral-strave sleep, which is typical from birds. We found all of these brain signature and behavior in the penguin. They are sleeping in the same way, basically, but the fragmentation of their sleep is quite unique.

It has been reported in a few other penguin, in two or three studies conducted in the 80s, where it was reported some drowsiness, some drosy states, that in a sense could be a sort of micro-sip, but they are not sustained like in the chin strap penguin. Is it possible you can learn something from the penguins about our own sleep? Maybe we can do the sort of kind of the same quick little naps as the penguins do? This would be great if we can just extrapolate just like this.

But I would say regarding on hold in sleep, we can't say much. We only can say that there is penguin that sleep in a fragmented way, that we are actually not able to do. If you try to sleep like a penguin, I'm pretty sure you would be disturbed cognitively, your attention would be quite a decrease. The only thing that we can say is that some animal developed some sleep adaptation,

and it showed that the evolution could have selected some specific physiological traits, and maybe one day we can extrapolate and found the mechanism and maybe we can sleep like this one way, but I think it's not tomorrow. So during the time that we've been talking, if I was a chin-strapped penguin, I'd have fallen asleep, what, maybe 80 times?

Probably, yes. Well, I'm awake enough to interview you. Fascinating work, doctor. Thank you very much for inviting me. Dr. Paul Antoine Lieborel, sleep biologist at the Neurosciences Research Center of Leone, France. That's all for this episode. On tomorrow's episode, The Climate Costs of Military Operation. See you tomorrow. I'm Rasha Aureti.