Short Wave - What Marsquakes Reveal About The Planet's Habitability

Episode Date: September 5, 2025

Mars is known for its barren desert landscape and dry climate. But two recent studies in the journals Nature and Science go beneath the surface, exploring the interior of the red planet using seismic data from NASA’s InSight mission. And now, this data is also giving scientists a glimpse into the planet’s history – to see how Mars evolved over billions of years and how its inner structure compares to that of Earth. Interested in more science news? Let us know at [e-mail].  Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.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, shortwaivers, Regina Barber here. And Emily Kwong. With our twice-monthly Science News Roundup featuring the hosts of all things considered. And today we have Juana Summers. Hello. Hi, thanks for having me back. So I heard there are two studies that tell us more about the inside of Mars and what makes it different from planet Earth.

Yes, and we're also looking into the potentially burgeoning future of plastic recycling, but without the sorting. Plus, why I see? scrolling on the toilet may not be good for you. We love news you can use. There's no science too near or far for us on this episode of Shortwave, the science podcast from NPR. Okay, Juana, I know we're going to eventually get to the toilet stuff, but out of the other two, where do you want to start? Let's start with Mars, the red planet. So there are two new studies looking at this using data from NASA's Insight Mission, which placed the first seismometer on Mars surface in 2018. This seismometer collected data about Marsquakes, which is sort of a way of taking an

X-ray of the planet. And now this data is giving scientists a glimpse into the planet's history to see how Mars has evolved over billions of years and how its inner structure compares to Earth. Okay, go on. What is going on inside Mars? So scientists used to think that the Mars core, the innermost layer, was liquid. But new research in the journal Nature shows that the core has an inner, like, solid core and a liquid outer core. And that structure is similar to Earth. Our core has a solid center and liquid outer layer underneath the Earth's mantle. Okay, so if I understand correctly, the internal structure of Mars might be a little more like Earth, according to this new study, but it can help me understand why this matters.

Yeah, so on Earth, the internal structure helps create a magnetic field, and that protects our atmosphere from the sun's radiation, and is part of why our planet is habitable. It's important for life. Yeah, and while Mars doesn't have a magnetic field, researchers think it did at some point in its history, so this new paper could help scientists figure out when and why the magnetic field faded. Well, don't leave me hanging. Did they come up with an answer? They still know now. They still do not know. And that's where the second study out recently in the journal Science comes in. And it looks at another layer of Mars, its mantle, and that sits

between its core and its crust. Now, traditionally, people thought Mars's insides looked like a smooth layer cake, but this paper suggests Mars mantle is chunky, like Rocky Road ice cream. Only Instead of marshmallows and chocolate, it's full of remnants of collisions from the planet's past when proto-planets and comets and asteroids crashed into Mars. Okay. You're making me hungry, but I'm going to set that aside for a second. What does that rocky road structure mean for the planet? Yeah, that's a good question. We asked one of the lead researchers, Konstantinos Haralambos. He told us that the fact that these pieces survived over billions of years suggests Mars mantle traps heat. That slows down the cooling of the planet's core and maybe part of the reason why Mars doesn't have a magnet. field. Taken all together, this new ice cream image and these two papers, they fill out details about Mars, lending new clues about how planets form and what makes them suitable for life. Right. Interesting. Let's go to the next science story, which is about plastic recycling. And I know that

a lot of plastic is used for packaging because I shop too much. Yeah, so much. Same. Every year, the average American discards nearly 500 pounds of plastic. A lot of that gets mixed together when it is tossed. So your milk jugs go in with your yogurt cups and your snack. wrappers and it all contains different plastic chemicals. So facilities use optical sorters or infrared scanners to sort it all out by type, which is pretty tedious and costly. In fact, less than 10% of plastic gets recycled worldwide. But scientists at Northwestern, Purdue, and Iowa State universities have figured out a new way to potentially bypass the need for pre-sorting mixed plastic waste. And they published this work in the journal Nature Chemistry this week. So what's

the secret? It's a nickel-based catalyst that's activated by a special powder. So when mixed with plastic waste that's heated, this catalyst actually breaks down what's known as polyolefin plastics. And polyolephins are important because they make up most of the plastic worldwide. Sandwich bags, garbage containers, food containers, milk jugs, all of those things. This is Tobin Marks, the senior author of this paper, and he spent much of his career making plastics. I obviously was concerned as I think all citizens are about these huge amounts of plastic just being dumped in landfills floating in the ocean. So he thought, what if I deployed the same technique I used to make plastics, a catalyst, to take plastics apart?

His team's catalyst cuts the carbon-to-carbon bonds, transforming the plastic into oils or waxes or hydrocarbon gas, which can be upcycled into higher-value products. Like what? Like lubricants, fuels, and even candlesticks. But do you think plastic facilities will really start? are using this catalyst? That is a question for the industry, right? Trolls-Scristrup, a chemist at Orhus University in Denmark, who is not a part of the study, said it's premature to evaluate what this catalytic system could do in the real world, but it's always a plus to present new technologies for solving our plastic problem. All right, y'all, let's end with this story that I

have been waiting for. It's about using a smartphone on the toilet. Yes. Yeah. I mean, sitting for so long in the toilet while you're looking at like too many TikTok was, I mean, we all knew. It was never going to be good for us. There's so many reasons. And a recent study in the journal, Ploss 1 says scrolling on your phone while in the bathroom is linked to a higher likelihood of getting hemorrhoids. Those sometimes painful soul and veins around your anus or lower rectum, specifically 46% more likely. I still have questions. How did researchers even think to study this? Well, Dr. Trisha Pasterisha is a neurogastroenterologist who just got curious. She sees a lot of patients who have hemorrhoids or GI issues, and she wanted to know if there was any research on what happens when you sit on the toilet too long looking at your phone. And to my great surprise,

nobody studied this. So Trisha and our team surveyed and collected medical data from 125 healthy individuals that were getting routine colonoscopies. It's a small study. But among these patients, they ask all these questions, people's fiber intake, if they've been pregnant, if they get constipated a lot, and if they use smartphones while on the toilet and for how long? And Trisha found that yes, indeed, scrolling on the toilet was a predictor for haemorrhoids. So then what's her advice for these folks? Yeah, that was one of my top questions and not for personal reasons at all. Sure, sure, sure.

I think in one sentence, it's don't bring your smartphone into the bathroom. Impossible. Yeah. She said, this is really hard to avoid, right? It's so comforting. So if you can't avoid bringing your phone in the bathroom, set a timer. But the advice I loved the best is that she encouraged people to bring people to bring back the bathroom library, like comics, you know, far side, poetry, things that are short

and not designed to keep you scrolling, you know, the way social media does. So in addition to your bed, before you sleep, you can add the bathroom to a growing list of places and times not to doom scroll. Oh, good, another excuse to get my phone out of my hand. Love that for me. I want to thank you for sitting through potty humor with us. No greater pleasure. Oh, thanks. Thank you. Oh. You can hear more of Wana on Consider This NPR's afternoon podcast about what the news means for you. This episode was produced by Rachel Carlson, Burley McCoy, and Megan Lim. It was edited by Rebecca Ramirez and Christopher and Taliatta. Tyler Jones checked the facts. Quasi Lee and Ted Mebane were the audio engineers. I'm Regina

Barbara. And I'm Emily Kwong. Thank you for listening to Shortwave, the science podcast from NPR.