An Exoplanet Where It Rains Sand

11:43 minutes

A big fuzzy red ball of clouds against the backdrop a vertical yellow horizon of a start in the background
Artist impression of exoplanet WASP-107b and its parent star. Credit: ESA, NASA

Scientists observing the exoplanet WASP-107b with the James Webb Space Telescope say that the planet has clouds of sand high in its atmosphere. The scientists detected water vapor, sulfur dioxide, and silicate sand clouds in the atmosphere of the planet, which is about the mass of Neptune but the size of Jupiter—stats that caused astronomers to describe it as “fluffy.” Science journalist Swapna Krishna joins guest host Flora Lichtman for a look at the planet. 

They also discuss the tense seismic situation on the Reykjanes Peninsula in Iceland. Since late October, earthquakes have been occurring there with increasing frequency, with hundreds of earthquakes detected over a recent 24-hour period. The quakes are due to underground magma flowing into the area and straining the earth’s crust. Measurements have also spotted an increasing concentration of sulfur dioxide gas in the area—which could point to an impending volcanic eruption. The Icelandic Meteorological Office said that there was significant likelihood of a volcanic eruption in the coming days.

Flora and Swapna also discuss other stories from the week in science, including a growing discrepancy in life expectancy between US men and women, a 3D printed robot hand with working tendons, efforts to control the spread of a drug lord’s escaped hippos in Colombia, and the tale of a tool bag—lost in space

Segment Guests

Swapna Krishna

Swapna Krishna is a journalist based in Philadelphia, Pennsylvania.

Segment Transcript

FLORA LICHTMAN: This is Science Friday. I’m Flora Lichtman in for Ira Flatow. Later in the hour, we’ll be helping with your holiday shopping list with a roundup of some of the best sciencey books for kids, plus the science of sweaters. Yes, that is a thing.

But, first, it’s been a tense few weeks on the Reykjanes Peninsula in Iceland. Earthquakes have been rumbling through the Peninsula for the last few weeks with increasing frequency. And, this week, they were seeing hundreds of earthquakes a day. Listen to this.



FLORA LICHTMAN: That sound is a translation of seismic data made by the Earthtunes app run by Northwestern University.


Each of those snaps and pops represents an earthquake. That 30-second clip captures the earthquake activity of about eight hours last Friday. Here to tell us what’s going on is Swapna Krishna, a science journalist based in Philadelphia. Welcome back to Science Friday.

SWAPNA KRISHNA: Thank you so much.

FLORA LICHTMAN: What is happening with all these earthquakes?

SWAPNA KRISHNA: Yeah, so this peninsula is in southwest Iceland, and scientists think a volcanic eruption might be imminent in the area. And so part of the reason for this is this area sits on the Mid-Atlantic Ridge, which is the boundary between the Eurasian and North American tectonic plates. And they’re drifting apart and creating rifts.

FLORA LICHTMAN: Yeah, so what’s causing all of these earthquakes, do we know?

SWAPNA KRISHNA: Right now, there is what’s called a magma dike, and that’s around 9.3 miles long. And it’s a tunnel of molten rock, basically, underneath the Earth. And that’s resulting in holes in the ground, cracks through streets. It’s a big deal.

FLORA LICHTMAN: I saw some of the pictures. It’s really dramatic– I mean, highways completely cracked in half with huge, gaping holes.

SWAPNA KRISHNA: Exactly. And so, right now, the main area of concern is Grindavik, which is a town of about 3,000 people. The town has been evacuated. So has the Blue Lagoon, which is a popular tourist attraction. And there have been thousands of earthquakes reported in the region. At one point, the number was 1300in a 24-hour period.

FLORA LICHTMAN: Whoa, that’s wild.

SWAPNA KRISHNA: Yeah, it’s a lot. Most of these are smaller earthquakes you can’t really feel. But a lot of them– they’ve been larger earthquakes. We’re talking 5.0 magnitude.

FLORA LICHTMAN: So a magma river under the ground– that does not sound like a good sign for eruption. What are people bracing for?

SWAPNA KRISHNA: Right now, we’re basically just waiting to see, is there going to be an eruption? We don’t know. If it’s going to happen, it’s probably going to happen within the next few days to three weeks. And if that doesn’t happen in that amount of time, the activity will likely quiet down.

FLORA LICHTMAN: When we say an eruption is imminent, does that mean– should I be picturing a Hawaiian volcano where magma is oozing out or Mount St. Helens explosion-level eruption?

SWAPNA KRISHNA: We’re not talking Mount St. Helens here. We are talking a Hawaii-style explosion. It’ll be slow-moving lava seeping out of the ground. The concern, though, is this is a populated area. Right now, they’re not worried about Reykjavik, but it’s only 25 miles from the epicenter where all of this is happening.


SWAPNA KRISHNA: And so the concern, really, is not just the lava but the fissures and the cracks that will open up and threaten these populated areas. Plus, scientists detected sulfur dioxide seeping from the ground, which means that any eruption will probably mean that this toxic gas will affect air quality. But it’s important to note, we’re not talking about the effect that the 2010 eruption had, which disrupted all kinds of air traffic, because that lava flow specifically happened through glacial ice, which is what threw up that giant ash cloud.

FLORA LICHTMAN: Let’s move to a planet with its own extreme environment. You have a story about a planet where it may rain sand.

SWAPNA KRISHNA: Yeah, this is a really interesting one. I love these weird exoplanets. So scientists using the James Webb Space Telescope identified an exoplanet. It’s called WASP-107b, and that’s about 211 light years away. It has clouds made of silicate particles in its upper atmosphere, and silicate is the main ingredient in sand, so sand clouds.

FLORA LICHTMAN: That sounds unpleasant.

SWAPNA KRISHNA: Yes, I would think so. But I think it’s important to note that this isn’t, like, a dust storm that’s whipping sand into the atmosphere like a sandstorm, what you would think of here on Earth. This is actual clouds made of sand.

FLORA LICHTMAN: How did they figure this out?

SWAPNA KRISHNA: So one interesting thing about WASP-107b is that it’s basically puffy. It’s got the mass of Neptune but the size of Jupiter. So, for context, Neptune is about 17 times more massive than Earth but just 1/19 of Jupiter’s mass.

So this planet is, like, puffy. You can think of it like cotton candy. And so one thing this allows us to do is look deeper down into the atmosphere than we would for, like, a Jupiter. So using JWST, they were actually able to look down into the planet’s atmosphere and see what’s going on.

FLORA LICHTMAN: That’s really cool. I mean, I love this because it creates this image in my head– rating sand on a cotton candy planet.


FLORA LICHTMAN: You had me at hello.


FLORA LICHTMAN: But does it tell us anything important about how planets work?

SWAPNA KRISHNA: Yes, it does. So here’s where it gets interesting. Silicate particles form clouds at around 1000 degrees Celsius. But the upper atmosphere of WASP-107b is only about 500 degrees Celsius. So that’s a pretty big temperature differential. And these clouds are higher up in the atmosphere than scientists would expect, so they must be traveling from a lower, warmer part of the atmosphere.

And so what they think is happening is there’s a sort of water vapor phenomenon, like we have here on Earth, except with sand. So down in the lower atmosphere, the sand particles evaporate and then travel on some sort of vertical updraft into the upper atmosphere. They form clouds, and then the cycle continues with it raining sand back into the lower atmosphere.

FLORA LICHTMAN: Science fact as science fiction, almost. This is wild.


FLORA LICHTMAN: So, back here on Earth, a more serious story– a growing discrepancy in life expectancy for US men and women. Tell me about this.

SWAPNA KRISHNA: Yeah, this is kind of a sad one. We’ve known for over a century that women, on average, live longer than men. This is not just a United States phenomenon. It’s international. But in the US, we’re seeing that gap widening after it was closing for a long time. And so a recent study says that the life expectancy for women is now six years longer than it is for men.

FLORA LICHTMAN: Wow. Why is that?

SWAPNA KRISHNA: Well, there’s a few reasons. COVID-19 played a large role, but the gap was widening before that, it’s important to note. But it did accelerate significantly from 2019 to 2021. Men died of the virus more often than women, and that was due to health factors but also behavior because men are less likely to go to the doctor than women are.

FLORA LICHTMAN: Were there any other factors?

SWAPNA KRISHNA: Yes, sadly– accidental deaths, like car accidents, drug overdoses, homicides, suicides, and deaths related to heart disease.

FLORA LICHTMAN: Here’s a follow-up to a story we mentioned a few years ago on Science Friday about the escaped hippos of the Colombian drug lord Pablo Escobar. What is the latest on these hippos?

SWAPNA KRISHNA: So these hippos have been living freely in the rivers of Colombia and reproducing. People think, now, it’s probably starting to disrupt the ecosystem. There’s more than hundreds of these hippos, now. Experts estimate their numbers could reach over a thousand by 2035, if there’s no intervention. So Colombia is engaging in this sterilization program for these hippos. And it is– I wouldn’t say it’s necessarily going well.


FLORA LICHTMAN: Well, I mean, it would be amazing if it were going well, right? They weigh tons, and I’ve heard hippos aren’t that friendly. How do you even do it?

SWAPNA KRISHNA: So they’re surgically sterilizing these hippos. And it’s just– there’s a lot of risks, both to the hippos– surgical sterilization has its issues– as well as to the people doing this because these hippos are huge. And there’s been a lot of rain in the area, so they’re having trouble baiting the hippos because there’s plenty of grass around, which is what the hippos eat.

FLORA LICHTMAN: Is this controversial at all?

SWAPNA KRISHNA: Yeah. Not everybody is happy about this. A lot of people don’t think it’s going to work. They’re trying to sterilize 40 hippos a year, and it’s already not going well. They’ve only done three so far.

But, also, there’s been research back in 2020 that these hippos might actually be beneficial. Most large, ancient herbivores are now extinct because of humans, and reintroducing them– the study used the example of hippos in Colombia, but also camels in Australia and wild boars in North America are helping to restore these ancient ecosystems.

FLORA LICHTMAN: Hmm. Let’s go to the technology world. You have a story about a 3D-printed robot hand with a twist.

SWAPNA KRISHNA: Yeah, this is really cool. Scientists were able to 3D print a robot hand with working ligaments and tendons. But the really big news here is that it was all in one go. They did not have to print the rigid and elastic materials separately.

FLORA LICHTMAN: Oh, that’s really cool because that’s been a drawback of 3D printing, right?

SWAPNA KRISHNA: Exactly. We know 3D printing has been around for a while, but the materials they can use are limited. The process introduces a lot of imperfections. So the product basically has to be scanned and examined and scraped after every layer. So that limits the kind of materials you can use because anything too soft or malleable will get squished during the scraping process.

FLORA LICHTMAN: Right. OK, finally, there’s something new to look for out in space this weekend– a tool bag?

SWAPNA KRISHNA: Yes, on the International Space Station or, more specifically, outside the International Space Station, two astronauts were performing a routine spacewalk to do some maintenance on their home in space. They were out there for a total of six hours and 42 minutes. But when they got inside, they found they had lost their tool bag.

FLORA LICHTMAN: This is why I can’t be an astronaut– this is one of the many reasons why I can’t be an astronaut because I can never find my keys. I would be the one leaving the tool bag in space, for sure.

SWAPNA KRISHNA: Yeah. And it’s important to note, it’s not a big deal. In terms of– they don’t need these tools for anything, and NASA did find the tool bag, and it is not in any way going to threaten any other spacecraft or the International Space Station. But the fun part is that you can actually see it with binoculars from the Earth.

FLORA LICHTMAN: I could see it myself?

SWAPNA KRISHNA: Yes, you can go to spotthestation.nasa.gov so you can figure out where the ISS will be in the night sky wherever you are. And then apparently if you look just before the International Space Station, you can see the bag as a star in the sky and the Space Station trailing it. You will need a pair of binoculars, but I just think that’s hilarious.

FLORA LICHTMAN: OK, everybody, get out your binoculars for this weekend. That’s about all the time we have. Swapna Krishna, a science journalist based in Philadelphia, thank you for joining us.

SWAPNA KRISHNA: Thank you so much.

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