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
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.
Key Discussion Points & Insights
1. Marsquakes and the Inner Structure of Mars
(02:14–04:34)
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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.”
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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.”
- Study 1: Nature—Mars has both a solid inner core and a liquid outer core, similar to Earth.
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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.”
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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)
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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.
2. Breakthrough in Plastic Recycling
(04:34–06:41)
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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).
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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.
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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.
3. Perils of Doomscrolling on the Toilet
(06:41–08:32)
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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).
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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.”
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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.”
Notable Quotes & Memorable Moments
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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…”
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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.”
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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.”
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Light Moment:
- Juana Summers (08:39): “Oh, good, another excuse to get my phone out of my hand. Love that for me.”
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
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.
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.