ARI SHAPIRO, HOST:
It's time now for our science news round up from Short Wave, NPR's science podcast. I'm joined by the show's hosts, Regina Barber and Emily Kwong. Hello, you two.
EMILY KWONG, BYLINE: Hey, Ari.
REGINA BARBER, BYLINE: Hi, Ari.
SHAPIRO: You have brought us three science stories that caught your attention this week. What are they?
BARBER: An interstellar visitor that's exciting astronomers.
SHAPIRO: Cool.
KWONG: A plastic-eating worm that could revolutionize recycling.
SHAPIRO: Nice.
BARBER: And why some animals' sense of smell varies by altitude.
SHAPIRO: I like this week's selection. Let's start with the interstellar visitor. Please tell me he has big eyes and a glowing finger.
KWONG: (Laughter).
BARBER: I wish. No, it's a comet. And most comets orbit our sun. You know, they're bound by our solar system. But this one came in 137,000 miles per hour from another star. And it's incredibly rare to get visitors like this.
KWONG: Yes, this comet's coming in hot. And astronomers spotted it. It's dubbed 3I/ATLAS on July 1 using the NASA-funded Asteroid Terrestrial-Impact Last Alert System, or ATLAS. This is a network of four telescopes, and the telescope in Chile caught this comet.
SHAPIRO: You both sound very blase about this comet traveling 137,000 miles an hour that was caught by the Last Alert System. Should we be ducking for cover?
BARBER: (Laughter) So no, we should not be ducking for cover. There's nothing to fear. Astronomers are guessing it'll stay roughly, like, 150 million miles from Earth.
SHAPIRO: OK.
BARBER: That's about, like, 1 1/2 times the distance from Earth to the sun. So it's really far.
KWONG: Yeah.
BARBER: It will come kind of close to Mars, though.
KWONG: Yeah, so no dinosaur fate for us.
SHAPIRO: OK. You said these kinds of visitors are rare. How many have we seen before?
KWONG: So this is only the third confirmed interstellar object to have zoomed past Earth. The first one was in 2017. You may remember ʻOumuamua, which means a messenger from afar arriving first in Hawaii.
SHAPIRO: Yeah.
KWONG: Yeah, there was all this public controversy at the time that maybe it was a spaceship.
TEDDY KARETA: People continue to debate this today, right? We don't really know. And the fact that we only had two or three weeks to study that object should tell you something about why.
BARBER: Yeah, I mean, I think a lot of astronomers don't think it's a spaceship, but we don't really know too much about it. That was planetary astronomer Teddy Kareta, who studies comets and the past interstellar objects. He says this comet 3I/ATLAS will be here for longer though.
KARETA: We haven't seen this object before. We'll have a couple of months to study it for real, and then it's gone forever.
BARBER: Teddy says studying these objects can help answer this big question - is our solar system unique or not? This comet most likely formed with planets around another faraway star, so studying it might tell us something about how other solar systems are made and how planets form there.
SHAPIRO: Cool. So scientists are going to have a couple months to study it. What about amateur astronomers? Will we be able to see it in the night sky?
KWONG: Yes, Ari, you, our listeners - in October, when the comet gets closer to Earth, if you venture somewhere far, far away from city lights...
KARETA: So under dark skies with a big telescope and some patience, maybe you might be able to see it. That might be the first time anyone has actually seen the light from an interstellar object with their own eyes.
BARBER: That's so cool. So come October, I'll be trying to spot it.
SHAPIRO: Sounds amazing. OK, next up, plastic-eating worms. Where did they come from?
BARBER: Yeah, they're called waxworms, and they're larvae of wax moths, and they're these little white caterpillars that chew through beeswax.
KWONG: And more than a decade ago, this beekeeper in Europe, who happens to be a scientist, was cleaning out her beehives, and she put the waxworms in a plastic bag. And when she got home, she realized the worms had eaten through the bag all on their own.
BARBER: What?
KWONG: And this intrigued scientists like Bryan Cassone at Canada's Brandon University.
BRYAN CASSONE: There wasn't anything known about how the waxworm is eating plastic, how much plastic they eat. Do they metabolize the plastic? Can this actually be used in plastic remediation?
SHAPIRO: Remediation meaning don't let the plastic sit in a landfill for 200 years.
KWONG: Yeah.
SHAPIRO: Like, are these worms the solution?
KWONG: OK, so yeah, that is the enticing question. Bryan experimented with it. He fed the worms a diet of polyethylene. That's the world's most commonly manufactured form of plastic. Usually polyethylene, to your point, takes decades or even centuries to decompose, but Bryan found...
CASSONE: It takes about 2,000 or so waxworms to fully consume a plastic bag in about 24 hours. And then we went into, well, how's that being done? So we looked at the bacteria, and we were able to isolate plastic-degrading bacteria from their guts.
BARBER: So his preliminary results suggest that the worms break down the plastic into, like, fatty acids. They metabolize it into energy, and whatever's leftover gets stored as fat.
KWONG: There's just one problem.
SHAPIRO: No, what's the problem?
CASSONE: When you feed them just on plastic, they die usually within a few days. So that's not good.
SHAPIRO: No, that's not good.
KWONG: Yeah, it's not a renewable recycling system, it seems.
BARBER: Yeah. So Bryan and his team figured out if you feed these worms a supplemented diet, like you throw in some carbs, some protein along with the plastic, that could help the waxworms live, like, longer healthier lives. And he presented his research this week at the Society for Experimental Biology Annual Conference in Belgium.
SHAPIRO: So what's the next step? Do I get to feed my plastic bags to worms?
KWONG: Well, one cool possibility - scientists are working on a way to isolate these worms' saliva and gut bacteria so they can just use the enzymes produced by these worms to directly break down plastics.
BARBER: Wouldn't that be cool? Yeah.
SHAPIRO: Yeah, amazing. OK, continuing with our critter theme, the third story is about animals that live at high altitudes. How high are we talking?
KWONG: Yeah, we're talking about animals that live 1,000 meters above sea level, so higher than 3,000 feet. You can picture Table Mountain in South Africa or Mount Diablo in California.
BARBER: Yeah, all kinds of animals have adapted to live at this altitude or higher. Think, like, bighorn sheep, alpaca, Andean guinea pigs. Where they live, as you probably know, there are fewer air molecules.
SHAPIRO: Right. You hike up a mountain, and you get out of breath because of the low oxygen.
BARBER: Right, the air is thinner, dryer. So Allie Graham, a biologist at the University of Kansas, wanted to know how these conditions impacted the animals' evolution, and she pursued this question by looking at genetic open source data.
ALLIE GRAHAM: I wanted to let, like I said, the data tell me what the story was rather than me, like, trying to, you know, like, have any control over that.
KWONG: She essentially screened the genomes of 27 different high-altitude species and compared them to their low-altitude relatives. So she compared rabbits that live at low altitude with pika that live at high altitude. These two lineages diverge several million years ago.
BARBER: And Allie did see a pattern. She and her team published their findings in the journal Current Biology this month.
SHAPIRO: OK, so drumroll, what did she find? What's the pattern?
BARBER: Yeah, she saw, like, a big reduction in genes related to smell. Like, nearly a quarter of these species' smell receptor genes were turned off. And Allie also saw a reduction in the part of the brain associated with smell.
KWONG: Maybe because it was better to invest genetic resources in taste or vision, though far more work is needed to be done to determine what ultimately drove this evolutionary mechanism.
SHAPIRO: Yeah, that is not what I expected you to say. Fewer smell receptors?
KWONG: Yeah.
SHAPIRO: Would the same be true for humans at high altitudes?
BARBER: So interestingly, no. Like, researchers compared the genomes of Tibetans who traditionally have lived at high altitudes with Han Chinese people who traditionally live at, like, lower altitudes, and looking at just their genetics found, like, no olfactory changes, none of these, like, gene differences.
KWONG: Yeah, Allie suspects it's because these groups haven't been separated long enough for a genetic signature related to smell to pop up.
GRAHAM: But at the same time, I, like, half joke, like, well, we'll check back in a couple million years and see whether or not that signal has popped up in human populations, right?
SHAPIRO: And if it has, we'll report on it.
KWONG: Absolutely. And in the meantime, Zack Cheviron, a biologist at the University of Montana who was not a part of the studies, says a nice follow up would be to go into the mountains and test the nose power of these animals directly.
SHAPIRO: Field work you can smell. I love it. That is Emily Kwong and Regina Barber from NPR's science podcast Short Wave. Subscribe now for new discoveries, everyday mysteries and the science behind the headlines. Thank you both.
KWONG: Thank you, Ari.
BARBER: Thank you, Ari. Transcript provided by NPR, Copyright NPR.
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