What Marsquakes Reveal About The Planet's Habitability

Summary

Podcast Summary: Short Wave

Episode: What Marsquakes Reveal About The Planet's Habitability

Date: September 5, 2025
Hosts: Emily Kwong, Regina Barber
Guest Host: Juana Summers

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Main Theme

This episode of Short Wave dives into new scientific discoveries about the interior of Mars, focusing on what recent marsquake data reveals about the planet’s habitability and its parallels with Earth. The episode also includes quick forays into two other topics: advances in plastic recycling, and the health risks of scrolling on your smartphone while on the toilet. With a blend of scientific curiosity and the show’s signature humor, the hosts dissect cutting-edge studies and translate them into actionable (and sometimes amusing) advice.

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Key Discussion Points & Insights

1. Marsquakes and the Inner Structure of Mars

(02:14–04:34)

• NASA's InSight Mission

  • Launched in 2018, placed the first seismometer on Mars to detect marsquakes.
  • Marsquake data acts like an "X-ray," revealing the planet's internal structure.
  • Emily Kwong (02:17): “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.”

• Two Key Studies:

  • Study 1: Nature—Mars has both a solid inner core and a liquid outer core, similar to Earth.
    • Regina Barber (02:42): “Scientists used to think that the Mars core... was liquid. But new research… shows that the core has an inner, like, solid core and a liquid outer core.”
    • Earth-analogous structure is significant for understanding past magnetic fields.
  • Study 2: Science—Mars’s mantle is not smooth; it’s uneven with remnants from ancient collisions.
    • Emily Kwong (03:44): “People thought Mars’s insides looked like a smooth layer cake, but this paper suggests Mars's mantle is chunky, like rocky road ice cream... full of remnants of collisions from the planet's past.”

• Importance for Habitability:

  • Earth’s internal structure helps create a magnetic field that shields life from solar radiation.
  • Mars likely had a magnetic field, but lost it—a crucial change in its potential for habitability.
  • Regina Barber (03:08): “On Earth, the internal structure helps create a magnetic field... and is part of why our planet is habitable. It’s important for life.”

• Memorable Analogy:

  • “Mars's mantle is chunky, like rocky road ice cream. Only instead of marshmallows and chocolate, it's full of remnants of collisions...” — Emily Kwong (03:44)

• Researcher Insight:

  • Konstantinos Harolambos (lead researcher): The survival of collision remnants suggests Mars’s mantle retains heat, slowing its core’s cooling—potentially connected to the loss of the magnetic field.

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2. Breakthrough in Plastic Recycling

(04:34–06:41)

• Current Plastic Recycling Limitations:

  • US average: nearly 500 pounds of discarded plastic per person per year, much of it unsorted and unrecycled (less than 10% globally).
  • Sorting requires complex, expensive technology (optical/infrared sorters).

• New Catalyst Technology:

  • Developed by researchers at Northwestern, Purdue, and Iowa State universities (published in Nature Chemistry).
  • Innovation:
    • Nickel-based catalyst activated by a special powder.
    • Efficiently breaks down mixed polyolefin plastics (most common plastic types).
    • Obviates need for prior sorting.
    • Converts waste to oils, waxes, hydrocarbon gases—can be upcycled into higher-value products like lubricants, fuels, and candlesticks.

• Expert Commentary:

  • Tobin Marks (05:45): “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.”
  • Troll Skristrup (06:24) (outside expert): Real-world impact remains to be seen, but the research provides encouraging new options.

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3. Perils of Doomscrolling on the Toilet

(06:41–08:32)

• New Health Research:

  • Recent study in Plos One links smartphone use on the toilet to a 46% increased risk of developing hemorrhoids.
  • Study surveyed 125 individuals undergoing routine colonoscopies, accounting for other factors (fiber, pregnancy, constipation).

• How the Study Happened:

  • Led by Dr. Tricia Pasrisha, a neurogastroenterologist who noticed a clinical correlation and wanted to investigate further.
  • Emily Kwong (07:43): “They asked all these questions… and Tricia found that, yes, indeed, scrolling on the toilet was a predictor for hemorrhoids.”

• Practical Advice:

  • Regina Barber (08:05): “I think in one sentence, it’s don’t.”
  • Instead, bring back “bathroom libraries” with comics or poetry—content not engineered for endless scrolling.
    • Regina Barber (08:10): “Bring back the bathroom library, like comics, you know, far side, poetry… things that are short and not designed to keep you scrolling.”

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Notable Quotes & Memorable Moments

• On Mars’s Rocky Road Mantle:

  • Emily Kwong (03:44): “Mars's 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…”

• On Plastic Recycling Motivation:

  • Tobin Marks (05:50): “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.”

• On Toilet Scrolling Solutions:

  • Regina Barber (08:10): “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.”

• Light Moment:

  • Juana Summers (08:39): “Oh, good, another excuse to get my phone out of my hand. Love that for me.”

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Timestamps for Important Segments

• Marsquakes & Planetary Habitability: 02:14–04:34
• Breakthrough in Plastic Recycling: 04:34–06:41
• Risks of Toilet Scrolling: 06:41–08:32

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Tone and Style

The episode is conversational, witty, and scientifically rigorous—balancing accessible analogies (“rocky road ice cream” for mantle structure) with expertise. The hosts encourage curiosity while grounding discussions in reputable recent research.

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For more, listen to Short Wave or follow up on referenced studies in Nature, Science, and Plos One. The episode closes with credits for the production team, before transitioning off into sponsor messages.

Transcript

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[Emily Kwong]

You're listening to Shortwave from npr.

[Regina Barber]

Hey, shortwavers. Regina Barber here and Emily Kwong with our twice monthly science news roundup featuring the hosts of All Things Considered. And today we have weekly Wanda Summers.

[Emily Kwong]

Hello.

[Juana Summers]

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.

[Emily Kwong]

Yes, and we're also looking into the potentially burgeoning future of plastic recycling, but without the sorting.

[Regina Barber]

Plus, why scrolling on the toilet may not be good for you.

[Juana Summers]

We love news you can use.

[Emily Kwong]

There's no science too near or far for us. On this episode of Shortwave, the science podcast from npr, foreign.

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Support for NPR and the following message come from. Edward Jones. What does it mean to live a rich life? It means brave first leaps, tearful goodbyes, and everything in between. With over a hundred years of experience navigating the ups and downs of the market and of life, your Edward Jones financial advisor will be there to help you move ahead with confidence.

[Emily Kwong]

Because.

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Because with all you've done to find your rich, they'll do all they can to help you keep enjoying it. Edward Jones, Member, SIPC this message comes from Schwab. Everyone has moments when they could have done better. Same goes for where you invest. Level up and invest smarter with Schwab. Get market insights, education and human help when you need it.

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[Regina Barber]

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

[Juana Summers]

Let's start with Mars, the Red Planet.

[Emily Kwong]

So there are two new studies looking at this using data from NASA's InSight mission, which placed the first seismometer on 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.

[Juana Summers]

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

[Regina Barber]

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.

[Emily Kwong]

And that structure is similar to Earth. Our Earth's core has a solid center and liquid outer layer underneath the Earth's mantle.

[Juana Summers]

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 helped me understand why this matters.

[Regina Barber]

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.

[Emily Kwong]

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.

[Juana Summers]

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

[Regina Barber]

Wanna want to 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.

[Emily 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.

[Juana Summers]

Okay, you're making me hungry, but I'm gonna set that aside for a second. What does that rocky road structure mean for the planet?

[Regina Barber]

Yeah, that's a good question. We asked one of the lead researchers, Konstantinos Harolambos. 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 cor and may be part of the reason why Mars doesn't have a magnetic field.

[Emily 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.

[Juana Summers]

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.

[Emily Kwong]

Yeah, so much shame. 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 cup and your snack wrappers. And it all contains different plastic chemicals.

[Regina 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.

[Emily 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 wastes. And they published this work in the journal Nature Chemistry this week.

[Juana Summers]

So what's the secret?

[Emily 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.

[Tobin Marks]

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

[Regina Barber]

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

[Tobin Marks]

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.

[Emily Kwong]

So he thought, what if I deployed the same technique I use to make plastics? A catalyst to take plastics apart.

[Regina Barber]

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.

[Juana Summers]

Like what?

[Emily Kwong]

Like lubricants, fuels, and even candlesticks.

[Juana Summers]

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

[Emily Kwong]

That is a question for the industry, right? Troll Skristrup, a chemist at Aarhus 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.

[Juana Summers]

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.

[Regina Barber]

Yes.

[Emily Kwong]

Yeah.

[Regina Barber]

I mean, smart. Sitting for so long in the toilet while you're looking at, like, too many tiktoks was. I mean, we all knew it was never gonna be good for us for so many reasons. And a recent study in the journal Plosone 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.

[Juana Summers]

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

[Emily Kwong]

Yeah, well, Dr. Tricia Pasrisha is a neurogastroenterologist who. Just 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.

[Regina Barber]

And to my great Surprise. Nobody studied this. So Tricia and her team surveyed and collected medical data from 125 healthy individuals that were getting routine colonoscopies. It's a small study, but among these.

[Emily Kwong]

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

[Juana Summers]

So then what's her advice for these folks?

[Regina Barber]

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

[Juana Summers]

Sure, sure, sure.

[Regina Barber]

I think in one sentence it's don't.

[Emily Kwong]

Bring your smartphone into the bathroom. Impossible.

[Regina Barber]

Yeah, she, she said this is really hard to avoid. Right. It's so comforting. So if you can avoid bringing your phone in in the bathroom, set a timer. But the advice 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.

[Emily 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.

[Juana Summers]

Scroll. Oh, good, another excuse to get my phone out of my hand. Love that for me.

[Regina Barber]

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

[Juana Summers]

No greater pleasure.

[Emily Kwong]

Aw, thanks.

[Regina Barber]

Thank you. You can hear more of Juana on consider this NPR's afternoon podcast about what the news means for you.

[Emily Kwong]

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

[Regina Barber]

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

[Emily Kwong]

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

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