A green comet, cancer-sniffing ants and new moons of Jupiter : Short Wave A green comet, cancer-sniffing ants, stealthy moons ... hang out with us as we dish on some of the coolest science stories in the news! Today, Short Wave co-hosts Emily Kwong and Aaron Scott are joined by editor Gabriel Spitzer. Together, they round up headlines in this first installment of what will be regular newsy get-togethers in your feed.

Have suggestions for what we should cover in our next news roundup? Email us at shortwave@npr.org.

From a green comet to cancer-sniffing ants, we break down the science headlines

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You're listening to SHORT WAVE from NPR.

Hey, hey, duderinos (ph). I'm Emily Kwong.


I'm Aaron Scott.

GABRIEL SPITZER, BYLINE: And I'm editor Gabriel Spitzer. And today, we're bringing you something kind of new and different for SHORT WAVE.

KWONG: That's right. We are hanging out to talk about some of the buzzy science stories that we're hearing. And this is going to be a new format we're trying. You'll be hearing this regularly.

SCOTT: We're going to comb through the news, dig through social media, read up on the scientific journals, all to figure out some of the science behind the headlines. Today, we've got for you insects that can sniff out cancer.

KWONG: And a comet that is green.

SPITZER: And crowning a new king of the moons in our solar system.

KWONG: We love a coronation. So today on the show, zip up those space suits and break out your magnifying glasses. You're listening to SHORT WAVE, the daily science podcast from NPR.

SPITZER: Just don't cook those ants with the magnifying glass.


KWONG: Yeah.


KWONG: So Gabriel Spitzer and Aaron Scott, we are each going to take turns talking about something sciencey (ph) in the news that's caught our attention. And I'm going to introduce my topic by asking you a question first. What are your plans tonight, for it is Friday and we are free?

SCOTT: I'm staying home. Just started watching "Andor," so I'm going to dream about the comings and goings of space.

KWONG: Sure.

SPITZER: And I'm, like, at the age where you don't really have plans for Friday night, you more have, like, habits.

KWONG: Friday night pizza and Blockbuster was the Kwong family tradition.

SPITZER: Oh, yeah.

KWONG: But today, in the Kwong-Coltharp household, me and my partner are going stargazing. And...


SCOTT: Romantic.

KWONG: Oh, wow. I love your reaction.

SPITZER: (Laughter).

KWONG: We're excited. We're looking for something really, really old that hasn't paid Earth a visit in an estimated 50,000 years.

SPITZER: Oh, wow.

KWONG: That's the last time that this comet came to our Earth. It's called C/2022 E3 (ZTF).

SCOTT: Love the way that astronomers name things.

KWONG: Right? It just rolls off the tongue.

SPITZER: Catchy name.

KWONG: Yeah. And the last time it was in our neighborhood was when Neanderthals and saber-toothed cats roamed the terrain. So it has really been a while.

SPITZER: Now I wonder if the Neanderthals ever had a date night to go, you know, check out the green comet.

KWONG: I love that idea.

SCOTT: Laid down a woolly mammoth hide and just stared up at the sky.

KWONG: They would have seen something that looked like a dirty snowball because that's kind of what a comet is. It's just a collection of dust and ice and gas. That's the frozen leftovers from our solar system.

SCOTT: Which doesn't sound that pretty. So how does it get to be green, Emily?

KWONG: Right. So the reason that people in the media are calling it the green comet is because when you take a photo of it, the cameras can pick up a certain kind of green light that's being emitted from the comet. And that's because the sun is reacting with this molecule in the comet called diatomic carbon. And the reaction produces a green glow.

SPITZER: Pretty.

SCOTT: Do we know where it comes from?

KWONG: So Aaron, we know this comet came from our solar system. There are a lot of comets up there. And they're just hanging out, orbiting in these big, elliptical patterns. And the way that we're able to see one on Earth is because that comet got a little gravitational nudge. It got pulled in by our sun. And as it nears the sun, it starts to melt. So the radiation from the sun releases all this dust and gas from the comet. She's shedding her cloak. And what's revealed is this glowing core called a coma and this long, fiery tail that can stretch for miles.

SPITZER: Oh, yeah.

KWONG: And that's why when you're a little kid and you draw a comet, you often are drawing, like, a ball of fire with a tail. That's the comet after it's, like, thawed.

SCOTT: So basically, the comet is walking the celestial runway, putting on a show for us.

SPITZER: (Laughter).

KWONG: That's right. That's right. So because it's such a rare moment, I like to think of it like it's an ancestor coming to visit, you know? It's this chemical message in a bottle from our early solar system. And astronomers are going to be looking for traces of certain chemicals on the comet. And then us, you know, non-astronomers here on Earth, we can still see it with our naked eye. If you live in the northern hemisphere, the comet is going to be hanging out kind of between the star at the end of the Big Dipper's cup and the North Star. So somewhere along, like, the spine of the big bear, you'll be able to spot this comet with a good pair of binoculars and a dark-enough sky.

SPITZER: And it's going to look down at Earth and say, hey, what happened to all the saber-toothed cats?

SCOTT: Where'd the kitties go? Where'd the kitties go?

KWONG: Yeah. But, Gabriel, you have also been stargazing, as I understand.

SPITZER: Yeah. So OK, I have today two important moon updates.

KWONG: Ooh, I love a moon update.

SPITZER: Saturn has been kind of the reigning king of the moons in our solar system for some time. Just take a guess about how many moons Saturn has.

SCOTT: I'm going to go with 77.

KWONG: I was going to say five, so...

SPITZER: Well, the answer is 83, 83 known moons.

KWONG: Holy moly, that's a lot of moon.

SCOTT: Oh, jeez.

SPITZER: That is the gold medal holder. But just in the last few weeks, the standings have actually changed.


SCOTT: Wait, wait, wait. Are you saying that, like, somebody has dethroned Saturn for having the most moons?

SPITZER: Exactly. Saturn has been toppled as the king of the moons.

SCOTT: Uh-oh. Who took the crown?

SPITZER: Well, the finding comes from the Minor Planet Center, which is a research institution and also the name of my ska band. To me, it just screams sort of, like, '90s alt-rock. Anyway - so they announced the discovery of a dozen new moons, all orbiting Jupiter. So Jupiter now has a total of 92, making it the new moon king of the solar system.

SCOTT: Gabriel, I got to ask, how is it that we haven't seen all the moons already? I mean, I kind of assume that we would have seen these things as soon as we got fancy telescopes.

SPITZER: Yeah, it's, like, kind of surprising that we can see distant galaxies and clusters and stuff like that. But here we have this planet that's just a couple of rocks down the road.

KWONG: (Laughter).

SPITZER: And it has mystery moons that we're still discovering. A lot of it is because Jupiter is so big and reflects so much light that the glare kind of, like, washes out our ability to actually resolve some of these smaller objects that are close to it. But these new findings have discovered mostly moons that are in the kind of outermost shell of Jupiter's moon layers. And one of the things that's interesting about them is that they revolve around Jupiter in the opposite direction of Jupiter's rotation. So it's like - it's called a retrograde orbit. And what that suggests to scientists is that these moons didn't form right there along with Jupiter. But they probably were actually, like, captured from somewhere else in the solar system.

SCOTT: So like, Jupiter is using gravity to, like, just lasso in strange objects as they float by like some sort of massive, celestial hoarder?

SPITZER: Yes, totally.

KWONG: It's a pirate moon.

SPITZER: (Laughter) It's a lasso hoarder pirate.

KWONG: (Laughter).

SPITZER: So yeah - so like, if an asteroid or some other large, kind of wandering body gets a little bit too close to Jupiter - Jupiter is so large that it has a massive gravitational field. And it can kind of grab it and just be like, you're a moon now.

KWONG: You're mine.


KWONG: Gabriel, that's fascinating. OK, so first moon update is that Jupiter is king of the moons.

SPITZER: Yes, yes.

KWONG: What's the second update?

SPITZER: Staying with Jupiter, as a matter of fact.


SPITZER: So there is another cool finding that just happened to come out in the last couple of weeks about the moon Io, which is one of the closest in and larger moons of Jupiter.

KWONG: That's the one that has, like, a ton of volcanoes on it, right?


KWONG: It's, like, very active?

SPITZER: Yes, exactly. And scientists have been looking really closely at all that volcanic activity to try and understand, like, what kind of volcanoes are these? What kind of eruptions is this? What's causing it? What they are finding is that the gravity from Jupiter, which, as we've mentioned, is immense, and then the gravity of all these other moons and orbiting objects push and pull and squeeze on Io so much that it creates all this internal friction. And that heats up...

KWONG: Poor Io.


SPITZER: ...The guts of the moon. So one of the scientists described it as being like a stress ball being squashed.

SCOTT: That sounds really rough.

SPITZER: And so the inside gets all hot. And it just courses with these eruptions. And so then you get this whole network of volcanoes. And lava flows all over the moon, even though, on average, this moon is, like, 200 degrees Fahrenheit below zero. But you have all these hot spots that are just kind of belching out plasma and debris and stuff like that into space all the time. It's pretty cool.

SCOTT: Sounds like a hard knock life for a moon. Yeah.

SPITZER: (Laughter).

KWONG: That's a lot of stress for one moon.

SPITZER: Yeah, but you get to hang out with Europa and Ganymede and all that stuff.

SCOTT: So moon party?

SPITZER: Oh, yeah. I mean, to me, the whole takeaway here is just that you don't have to go, you know, outside the Milky Way or, like, a spaceship...

KWONG: Yeah.

SPITZER: ...Or a powerful telescope, like the James Webb or something, to get new science from space. Like, there's all kinds of new discoveries that are in our relatively small solar system neighborhood here, too.

KWONG: Speaking of small neighborhood discoveries, Aaron Scott, you latched onto some pretty cool news this week involving ants.

SCOTT: Yeah.

KWONG: What's going on there?

SCOTT: So while you both have been staring up at the stars and contemplating cosmic drama, I've been looking down at something very itty-bitty. Last week, a team of scientists in France put out this study saying they had trained ants to sniff out cancer.

SPITZER: Wait - cancer, like, in humans?

KWONG: Say more.

SCOTT: Well, human cancer in mice.


KWONG: So wait, go...


KWONG: That's very impressive. How do you even train an ant?

SCOTT: I mean, we got flea circuses, right? So why not ant laboratories?

KWONG: Fair.

SCOTT: It's through association, kind of similar to, like, training a dog a trick and giving it a treat. What they did is they grafted some human breast cancer tumors onto mice. And then they took urine from those mice and put it out next to sugar water, and then trained the ants that, you know, you're going to find a sweet treat near any urine that smells like this.


SCOTT: And then they test it. They took away the sugar water. And they put out some urine from healthy mice. And then they found that the ants spent 20% more time around the urine from the mice with the tumor than they spent around the healthy mice urine because they thought that they would find some sugar water nearby.

SPITZER: Did we know that cancer pee smells different?

SCOTT: We did know that cancer pee smells different because these tumors release these volatile organic compounds - these VOCs - that can be detected in urine. It can be detected in sweat. It can be detected in the vapor that we breathe out. So I mean, they've got dogs that can detect this. And of course, these scientists then went back, and using, you know, technology, were able to actually tell that there is a chemical difference between the pee from healthy mice and the pee from mice with these human tumors grafted to them.

KWONG: Got you. This makes me really, really appreciate, then, the smell capabilities of ants. I mean, they must be very good.

SCOTT: The remarkable thing about the ant sense of smell is it really just took, like, three repetitions of this process...


SCOTT: ...To train a single ant, like 10 minutes, whereas it takes months to train a dog.


KWONG: The fact that they used the sugar water as a reward to teach them to associate that treat with this certain smelling urine, I mean, that has some pretty powerful possibilities for cancer detection, no?

SPITZER: Yeah. Like, is this a real diagnostic thing, Aaron? Or is this just, like, some kind of basic research?

SCOTT: This was just proof of concept.


SCOTT: It used lab mice and, you know, one type of cancer, whereas human patients are way more complex, with different types of cancer, different diets, different ages.


SCOTT: So it's going to take a lot more work to be able to tell if ants can smell the difference between urine with cancer or the urine from a healthy human.

SPITZER: Yeah. I mean, like, I don't know a lot about ants. But I do remember hearing that they have this whole chemical kind of language where they communicate with each other through pheromones and leave little chemical trails and all that kind of stuff. So I guess it makes sense that their little sniffers are really, really fine-tuned to differences in smell.

SCOTT: Exactly. I mean, these are - you know, dogs, ants, they all can, like, follow these pheromone smells. And they're experiencing the world in ways that our human noses are completely incapable of doing. But, you know, in an alternate world, maybe if we'd evolved from canines, we would also be going around sniffing pee and being able to tell really important things about each other, like our health or moods.

KWONG: I am glad I don't live in that parallel universe.

SCOTT: (Laughter).

KWONG: But that is a thought-provoking last statement, Aaron.

SPITZER: (Laughter).

KWONG: Thank you both so much for coming on and talking about what caught your eye. And I hope you keep your eyes peeled to the sky and also to the dirt...

SCOTT: Below our feet.

KWONG: ...For all the critters that are down there doing cool things.


KWONG: If you have science stories or tips that you want us to chat about and look into, email us. We're at shortwave@npr.org. This episode was produced by Thomas Lu. It was edited by our supervising producer, Rebecca Ramirez, and fact-checked by Anil Oza. The audio engineer was Alex Drewenskus. Brendan Crump is our podcast coordinator. Beth Donovan is our senior director of programming. And Anya Grundmann is our senior vice president of programming. I'm Emily Kwong.

SCOTT: I'm Aaron Scott.

SPITZER: And I'm Gabriel Spitzer.

KWONG: And we are going to wish you farewell. Goodbye.

SPITZER: Farewell from SHORT WAVE.

SCOTT: Goodbye.


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