What Marsquakes Reveal About The Planet's Habitability

Mars is known for its barren desert landscape and dry climate. But two recent studies in the journals Nature https://www.nature.com/articles/s41586-025-09361-9 and Science https://www.science.org/doi/10.1126/science.adk4292 go beneath the surface, exploring the interior of the red planet using seismic data from NASA’s InSight mission. https://science.nasa.gov/mission/insight/ 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 [email protected] mailto:[email protected]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ atplus.npr.org/shortwave http://plus.npr.org/shortwave. 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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• 0:21Regina Barber?

  Hey, Short Wavers. Regina Barber here.

• 0:22Emily Kwong?

  And Emily Kwong.

• 0:24Regina Barber?

  With our twice monthly Science News roundup, featuring the hosts of All Things Considered. And today, we have Juana Summers.

• 0:31Emily Kwong?

  Hello.

• 0:32Speaker 03

  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.

• 0:39Emily Kwong?

  Yes, and we're also looking into the potentially burgeoning future of plastic recycling, but without the sorting. Plus, why scrolling on the toilet may not be good for you.

• 0:49Speaker 03

  We love news you can use.

• 0:51Emily Kwong?

  There's no science too near or far for us on this episode of Short Wave, the science podcast from NPR.

• 1:04Speaker 04

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• 2:28Regina Barber?

  Okay, Wana, I know we're gonna eventually get to the toilet stuff, but out of the other two, where do you want to start?

• 2:35Speaker 03

  Let's start with Mars, the red planet.

• 2:38Emily Kwong?

  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 Mars quakes, 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.

• 3:00Speaker 03

  Okay, go on. What is going on inside Mars?

• 3:03Emily Kwong?

  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 Earth's core has a solid center and liquid outer layer underneath the Earth's mantle.

• 3:20Speaker 03

  Okay, so if I understand correctly, the internal structure of Mars might be a little more like Earth, according to this new study, but help me understand why this matters.

• 3:28Emily Kwong?

  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.

• 3:49Speaker 03

  Well, don't leave me hanging. Did they come up with an answer?

• 3:51Regina Barber?

  They still...

• 3:51Speaker 03

  Wana wants to know now.

• 3:53Regina Barber?

  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.

• 4:04Emily Kwong?

  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 protoplanets and comets and asteroids crashed into Mars.

• 4:21Speaker 03

  OK, 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?

• 4:26Regina Barber?

  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 may be part of the reason why Mars doesn't have a magnetic field.

• 4:44Emily Kwong?

  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.

• 4:54Speaker 03

  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.

• 5:02Emily Kwong?

  Yeah, so much. 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.

• 5:17Regina Barber?

  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.

• 5:27Emily Kwong?

  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.

• 5:41Speaker 03

  So what's the secret?

• 5:42Emily Kwong?

  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 polyolefins are important because they make up most of the plastic worldwide.

• 5:58Speaker 05

  Sandwich bags, garbage containers, food containers, milk jugs, all of those things.

• 6:05Regina Barber?

  This is Tobin Marks, the senior author of this paper, and he spent much of his career making plastics.

• 6:10Speaker 05

  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.

• 6:21Emily Kwong?

  So he thought, what if I deployed the same technique I use 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.

• 6:37Speaker 03

  Like what?

• 6:38Emily Kwong?

  Like lubricants, fuels, and even candlesticks.

• 6:41Speaker 03

  But do you think plastic facilities will really start using this catalyst?

• 6:44Emily Kwong?

  That is a question for the industry, right? Troll Skristrop, 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.

• 7:01Speaker 03

  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.

• 7:08Regina Barber?

  Yes. Yeah. I mean, sitting for so long on the toilet while you're looking at like too many TikToks was, I mean, we all knew it was never going to be good for us.

• 7:16Speaker 03

  For so many reasons.

• 7:17Regina Barber?

  And a recent study in the journal PLOS1 says scrolling on your phone while in the bathroom is linked to a higher likelihood of getting hemorrhoids, those sometimes painful swollen veins around your anus or lower rectum, specifically 46% more likely.

• 7:32Speaker 03

  I still have questions. How did researchers even think to study this?

• 7:37Emily Kwong?

  Well, Dr. Tricia Pastricha 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.

• 7:54Regina Barber?

  So Tricia and her team surveyed and collected medical data from 125 healthy individuals that were getting routine colonoscopies. It's a small study.

• 8:02Emily Kwong?

  But among these patients, they asked all these questions.

• 8:05Regina Barber?

  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 Tricia found that, yes, indeed, scrolling on the toilet was a predictor for hemorrhoids.

• 8:18Emily Kwong?

  So then what's her advice for these folks?

• 8:20Regina Barber?

  Yeah, that was one of my top questions and not for personal reasons at all.

• 8:24Emily Kwong?

  Sure, sure, sure. I think in one sentence, it's don't bring your smartphone into the bathroom.

• 8:29Regina Barber?

  Impossible. Yeah. She said, this is really hard to avoid, right? It gets 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 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.

• 8:52Emily Kwong?

  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.

• 9:00Regina Barber?

  Oh, good. Another excuse to get my phone out of my hand.

• 9:02Emily Kwong?

  Love that for me.

• 9:04Regina Barber?

  Juana, thank you for sitting through potty humor with us.

• 9:08Emily Kwong?

  No greater pleasure.

• 9:10Regina Barber?

  Aw, thanks.

• 9:11Emily Kwong?

  Thank you.

• 9:13Regina Barber?

  You can hear more of Juana on Consider This, NPR's afternoon podcast about what the news means for you.

• 9:18Emily Kwong?

  This episode was produced by Rachel Carlson, Burleigh McCoy, and Megan Lim. It was edited by Rebecca Ramirez and Christopher Intagliata.

• 9:24Regina Barber?

  Tyler Jones checked the facts. Kwasi Lee and Ted Mebane were the audio engineers. I'm Regina Barber.

• 9:29Emily Kwong?

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

• 9:44Speaker 00

  Stay tuned for the following announcements and messages from our sponsors.