JUANA SUMMERS, HOST:
It's time now for our science news roundup from Short Wave, NPR's science podcast. I am joined by the show's two hosts, Regina Barber and Emily Kwong. Hi, y'all.
EMILY KWONG, BYLINE: Hi.
REGINA BARBER, BYLINE: Hey.
SUMMERS: So I know that, like usual, you have brought us three science stories that caught your attention this week. Tell us what they are.
BARBER: New research that tells us more about the inside of Mars and what makes it different from Earth.
KWONG: And speaking of Earth, we have a new way to recycle plastic.
BARBER: And why scrolling on the toilet may not be good for you.
SUMMERS: I have a lot of questions.
BARBER: (Laughter).
SUMMERS: But let's start with Mars, the red planet. Emily, why don't you kick us off?
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.
SUMMERS: OK, go on. What is going on inside Mars?
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.
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.
SUMMERS: OK, 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.
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.
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.
SUMMERS: Well, don't leave me hanging. Did they come up with an answer?
BARBER: They still...
KWONG: Juana wants to know now.
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.
KWONG: Now, traditionally, people thought Mars' 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.
SUMMERS: OK, you're making me hungry, but I'm going to set that aside for a second.
KWONG: (Laughter).
SUMMERS: What does that rocky road structure mean for the planet?
BARBER: Yeah. That's a good question. We asked one of the lead researchers, Constantinos Charalambous. 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.
KWONG: Taken altogether - 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.
SUMMERS: All 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.
KWONG: Yeah, so much.
BARBER: Same.
KWONG: 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.
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.
KWONG: But scientists at Northwestern, Purdue and Iowa State universities have figured out a new way to potentially bypass the need for presorting mixed plastic waste. And they publish this work in the journal Nature Chemistry this week.
SUMMERS: So what's the secret?
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.
BARBER: This is Tobin Marks, the senior author of this paper, and he spent much of his career making plastics.
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.
KWONG: So he thought, what if I deployed the same technique I used to make plastics - a catalyst - to take plastics apart?
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.
SUMMERS: Like what?
KWONG: Like lubricants, fuels and even candlesticks.
SUMMERS: But do you think plastic facilities will really start using this catalyst?
KWONG: That is a question for the industry, right? Troels Skrydstrup, 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.
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.
BARBER: Yes.
KWONG: Yeah.
BARBER: I mean, 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 going to be good for us.
KWONG: For so many reasons.
BARBER: And a recent study in the journal PLOS One 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.
SUMMERS: I still have questions. How did researchers even think to study this?
BARBER: Yeah.
KWONG: Well, Dr. Trisha Pasricha 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.
TRISHA PASRICHA: And to my great surprise, nobody studied this.
BARBER: So Trisha and her team surveyed and collected medical data from 125 healthy individuals that were getting routine colonoscopies. It's a small study.
KWONG: But among these 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 Trisha found that, yes, indeed, scrolling on the toilet was a predictor for hemorrhoids.
SUMMERS: So then, what's her advice for these folks?
BARBER: Yeah, that was one of my top questions and not for personal reasons at all.
SUMMERS: Sure, sure, sure.
PASRICHA: I think in one sentence, it's don't bring your smartphone into the bathroom.
KWONG: Impossible.
BARBER: Yeah.
SUMMERS: (Laughter).
BARBER: She said, this is really hard to avoid, right? It's so comforting. So if you can't avoid...
SUMMERS: (Laughter).
BARBER: ...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...
SUMMERS: Oh, yeah.
BARBER: ..."Far Side," poetry. Things that are short and not designed to keep you scrolling, you know, the way social media does.
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.
SUMMERS: OK, another excuse to get my phone out of my hand. Love that for me.
BARBER: Yes.
SUMMERS: That's Emily Kwong and Regina Barber from NPR's science podcast, Short Wave. Subscribe now for new discoveries, everyday mysteries and the science behind the headlines. Thanks, y'all.
KWONG: Thank you.
BARBER: Thank you.
(SOUNDBITE OF TOM SZIRTES' "BLISSED OUT") Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
