Bizarre exoplanet clouds + Counting insects with weather radar

Hey, it's Flora and you're listening to Science Friday. It seems like every week a new exoplanet drops. NASA counts six thousand official alien worlds, with around eight thousand more suspected. They're stuck on the wait list till more research can be done to confirm them. One way to spot an exoplanet is to use a telescope to carefully look at the light of a star, watching for a tiny periodic dip in brightness as a planet crosses in front of it.

But now researchers say that using this transit method, they detected not just a planet, but its clouds. And the clouds on this one gas giant, some 700 light years away, are super weird. They're made of rock. Here to tell us more is Dr. David Sing. He's a Bloomberg Distinguished Professor of Earth and Planetary Sciences at Johns Hopkins. Hey David. Hello. Thank you for having me. Thanks for being here. Tell us about this planet that you've been looking at and what the weather's like.

Well, this is a planet what we call a hot Jupiter. It's a gas giant, much like Jupiter, but it's orbiting very close to a host star, and as as a result, it's heated up to very high temperatures. up to fifteen hundred degrees Kelvin. And at those temperatures, what we normally experience as say rocks actually can form uh clouds in the atmosphere. Like they're being boiled off the surface.

Well, this is a gas giant, so there's no surface, but indeed they're um if you get hotter than about fifteen hundred, they're these rocks are actually in vaporous form. And as it gets colder, they can condense into solid small particles. Yeah, how should I be imagining these clouds? Are they puffy like our clouds or are they filled with little granules? Well, I mean you can sort of think of them as little granules, but more like micron size tiny sand particles, like say quartz.

here on Earth. So, you know, we don't really know how puffy and so forth they are, but just imagining sort of a big puffy cloud made of little quartz crystals. Um, it's a good way to think about them. I mean does that mean the atmosphere's doing something special to keep them? Yes, actually it's a big surprise on this planet, what we find is the clouds are at very high altitudes. So

well above their stratosphere, up into even the mesosphere, and actually large particles. So it was a actually a big surprise to see them up there. Everyone expected you know, something that big and heavy just to fall out. And so normally we would see the clouds at a much lower level. And so the planet must have actually very vigorous mixing, turbulent mixing, to keep those uh sand clouds that that high in the atmosphere. It's it's really surprising.

What would they you know, if I could bubble up ab uh below them, I guess. What would they look like in the sky? Is it like a haze or a fog or are they, you know, like a cumulus cloud here on Earth? It would look like a a very actually thick, dense cloud. So on this particular planet, the clouds are actually even confined to the morning side of the planet. So the morning side is completely cloudy and the evening side is actually completely clear. It's it's much hotter and those clouds can't form.

And so I kind of imagine it's sort of like you're in San Francisco and in the morning it's all cloudy and you can't see anything. And then by the afternoon, they've all boiled off and you can see the clear sky. They burn off, as we say.

How do you get enough resolution to be able to see the clouds? I mean that seems amazing. Yeah, well we've been studying exoplanets through the transit technique for nearly twenty-five years and we've been mainly using the Hubble Space Telescope during that time. But now we have uh the powerful JDVST telescope and that's given us actually two important advances to be able to make this measurement. Uh the one is

Hubble is in low Earth orbit. It's orbiting around the Earth about every ninety minutes. And so it spends half of its time on the day side of our planet and half of it on the night side. Well, when we look at these transit events of these exoplanets, you know, we're looking at it over the course of several hours.

But that means the Hubble is actually spending half of its time on the wrong side of our planet. And so actually you can't even observe the full transient event continuously, which is uh kind of prevents this measurement from being made. But JUST is out beyond the Earth and the Moon, and it can stare continuously for hours or even days. So that's one key aspect of Just T that's important. And the other is that the telescope

J V S T it just so much bigger. It's has seven times the light collecting ability. So that means what took Hubble more than an hour to make a measurement, now JVST can do in say 10 minutes. And actually that sort of 10 minute timeframe is really important because in order to separate out the spectrum of an exoplanet from the morning to the evening side, you have to wait for this little ten minute window where only part of the planet

is covering uh the star. But that event doesn't last very long, about ten minutes. And so JBS D is big enough to be able to take a spectrum of a planet uh during that short window. Do these clouds provide clues into other big questions like what the planet is made of or what the atmosphere is made of?

Absolutely. So there's kind of two key questions we can start to unravel because We've been looking at these planets for quite some time and we've see uh molecules in their atmospheres and the clouds together, but now we can separate these out quite cleanly. And we can look, for instance, at the clear atmosphere and what its chemical composition is. And these gas giants are Basically, like fossilized records for when the planet formed. So we want to use these as

basically records to figure out how these planets form and evolved. And many of these types of planets we do not have in our own solar system, like hot Jupiters or sub Neptunes. And some of these types of planets are actually the most common found throughout the galaxy, yet we don't really have a good idea how they form or evolved. And so

by measuring the chemical composition cleanly with this technique, we can start to unravel that mystery. And there's another important aspect was actually just studying these clouds themselves. So clouds and modeling them are the biggest uncertainty we have in studying and modeling atmospheres. And that includes our own Earth's atmosphere. And you know, with these exoplanets, we're actually using the same models that

uh are used to measure the weather and predict the weather on Earth. So it actually turns out that um we don't know the physics of cloud formation and how it interacts that well. So by measuring how clouds are formed and the dynamics in these different extreme environments, we can actually improve the physics of our overall model. That's wild. So alien clouds could help us understand our own clouds better. Yeah, absolutely. Are clouds common on exoplanets? Is this a a feature every planet has?

Um, for most planets indeed, we seem to f you know, it's very common for all exoplanets that we almost see there's a few out there that are just so so hot. that are uh they're mostly cloud free, but uh those are kind of a tip of the iceberg, you know, extreme planets. But more or less when we look at an exoplanet and look at a spectra, we see clouds and that

That's uh it's a similar characteristic as what we have in our solar system. Every planet in our solar system with substantial atmosphere has uh as clouds. I love to think of that as like a a feature of the universe. Clouds, a consistent feature of the universe. It is and it's an important feature and as an astronomer we typically hate clouds, but but it's actually great to study them and actually learn about, you know, what nature provides.

Dr. David Singh is a Bloomberg Distinguished Professor of Earth and Planetary Sciences at Johns Hopkins. Thanks for coming on the show today. Oh thank you very much. After the break, turning from alien clouds of rock to the clouds of insects flying above you right now. Stick around. Science Friday brings the joy of discovery to millions of curious listeners every week. When you sponsor Science Friday, you connect with a dedicated audience that values knowledge, exploration, and learning.

These are folks who love getting into the details, who actively engage with ideas, and who value trustworthy information. Learn more at sponsorship.wnyc.org.

Next time you're outside, take a moment and look up at the sky. Chances are, somewhere in that column of air above you, there are at least four insects sharing that one square meter of the planet with you. That's one of the findings from a group of researchers who used weather radar across the US to map out airborne insects over a ten year period.

doctor Elska Tielens is an ecologist with the Swiss Federal Institute for Forest, Snow and Landscape Research and one of the researchers on that project. Hey Elska. Hey, thanks for having me. Okay, so to be precise, you found four point three aerial insects per three footish square on average. That's a lot. That's gotta add up very quickly.

That's right. It is quite a lot, and it adds up to a hundred trillion if you sort of extrapolate across the entire surface of the uh contiguous United States. A hundred trillion insects above us. One hundred trillion insects on a warm, nice summer day, you know, those those days when you yourself see an insect out because it's nice and it's good conditions, a hundred trillion insects above the US.

And we're just talking about airborne insects. So we're not talking about like the centipede crawling underneath my shoe right now. That's correct. Um, radar are great for seeing what's up in the sky. And so we're not even really talking about what is at your eye level, we're talking about what is much higher. When you look up into the blue of the sky, um, it looks like maybe there's nothing there, but actually there's a hundred trillion insects up there.

Yeah. You know, we've seen weather radar used for for tracking bird migrations, but I was really surprised that it could see the resolution of insects. Yeah, that's right. It's a it's a tool that w folks have been developing for tracking birds. That's um the the first place that people went when they realized actually we see a lot of biology.

On these weather radars. And as a meteorologist, you say, Oh, that's not what we're interested in. Let's throw that out. And as biologists, we said, Oh, what if we throw out all of Meteorology and we throw out all of the weather and instead we take this part that the meteorologists are not so interested in.

the biology. Um, and and it makes sort of sense that you would be able to see insects when there's more of them in the air because raindrops themselves are not particularly big, right? But when you get a cloud of raindrops, suddenly we start to see that on radar. And so in the same way that you can use um a a weather forecast and look at the radar to see when rain is going to come into your local area, you can see on the weather radar when there are lots of insects in the sky.

I mean, are there some insects that are too small to see? Like a gnat or noceum, for example. Not so much too small, but maybe too few, right? And and part of that is sort of Um, the radars are very sensitive, but there's a lot of noise on the signal. And so there has to be sort of sufficient signal, sufficient density of insects for our methods to be able to differentiate and say, okay, this is this is real insect. Can you tell which species of insects you're looking at?

No, not at all. The radar totally doesn't know and doesn't care. Um and and that's an interesting thing about this tool. It's really good for quantifying abundances and and looking at a standardized way of measuring how many insects are out there. It's the same. across all these different radars, across different regions, across the entire United States.

But if you wanted to know more about what's happening specifically with this population or that, then you need to combine it with sort of local surveys or citizen science or other types of tools that we have.

You looked at a ten year period from twenty eleven to twenty twenty one. Did you see any big trends? Yeah, interestingly, we sort of expected everyone's been really worried about insect declines. Obviously there's a lot of studies demonstrating that insect biodiversity is going down in many species um insect abundances have been declining over the past ten something years.

we sort of expected to find widespread declines and instead we found that at the continental scale, insect abundances are pretty stable. There's areas where they're declining and there's areas where they're increasing and it sort of offsets each other. that over the ten year period um we don't see a strong trend. Although we don't know which insects, right? So we could be sort of compensating for the loss of some insects with the gain in other insects.

That's exactly right. You've got winners and losers probably, some species doing really well. And the species that we know sort of don't handle anthropogenic change so well, maybe are declining. And so there's a balancing act happening of um increases and and declines in different species that results in this. uh stable trend. So and that's really surprising because we do hear so much about this insect apocalypse. How should I interpret this data set in that context?

Yeah, I mean that's a really good question. And I think this is an important data source for that. But it's possible that what we're looking at is actually sort of a shifting baseline. That compared to this baseline from 10 years ago, we're not seeing declines because some of these took place. thirty, forty years ago when we had big land use change or agricultural intensification. And so if you only start measuring after the declines have already happened, then you're not gonna capture that.

But I think it's extra important or it sort of demonstrates why weather radar could be a really good tool for standardized monitoring. And so ten and twenty years later we can come back and compare and say, oh here's the larger time window, here's the bigger picture for this. Are there more insect rich places in the US? What's like insect capital USA?

Um, I think the Gulf is insect capital of the USA. And I think that this is true anyway. When you when you drive down there you really notice people talk a lot about, uh, when I was growing up how many s how many insects would splat on the windscreen. You take a road trip down to Texas or down to Mississippi or coastal Georgia and and you really do see that

There's so many insects out there. And I think the other thing is the radar's really good at picking up insects that are high up in the sky and so areas where the conditions are really good for insects to move long distances in the sky. um such as above the plains, those are also areas where we see lots and lots of insects. Where are the insect deserts?

So one finding from this study was that areas where in the winter we see a lot of warming, um, insect populations have been declining. And there's some covariation there with uh development. Areas where we've had a lot of human development and changes in land use over the past 10 years is also areas where we see greater declines in insects. And so in your urban areas, of course, some insects do really well. We see fewer insects.

I was just thinking about the cockroaches of New York City and how there's probably like a hundred trillion of those just on this island. But thank goodness they don't fly so high and so uh they don't show up on the radar.

I mean, has this data always been in weather radar and it's a matter of m using machine learning to pick it out or is this an advance in the radar itself? Uh we had to develop the methods to say how do we pick out the insects from the radar? But um you can go back, you know, fifty, sixty years to early years of using radar and find

um studies of people identifying this. Even when people first started using radar and thinking about it as a tool to see um planes flying over, folks would report, man, we're seeing these things we call angels on the um on the screen because there are these echoes and they don't correspond to a plane flying in. And so it must if it's something that you can't see, so maybe it's an angel, right? And it turned out actually those were mostly birds that

showed up. But that was before we thought about biology as being visible on a weather radar. Hm. Are the insects migrating or moving? Yeah. Um it sort of depends on when you're looking. You definitely see huge abundances of insects migrating. Um especially when you're looking in the fall, a lot of the abundances come from insects that are coming up from Wisconsin or coming up from Minnesota and moving down

to escape the cold weather, um, the cold winters that they get up there. But in the middle of the summer, it's just activity of of local populations that take to the sky and fly really high up. Um and so it sort of differs at you have different insects maybe that are really abundant at different times of the year. So you get these mayfly explosions uh over the Great Lake.

just for a couple of days or or if you're looking sort of out west, you see big numbers of grasshoppers that show up on the radar really well. You did this research while you were a postdoc in Oklahoma. You're now in Switzerland. Are there differences in the insects that you see on the radar where you are now?

Yeah, totally. There there are definitely different species in these different areas. And I think one of the things that's that's striking is the US is such a diverse place. There's so many different regions and so many different biomes included in the vast network of weather radars that we have. It's such an amazing resource to have. a huge um a huge land area that is covered by radar that we can

do this kind of continental scale study on. Whereas in Europe it's a little bit more challenging. All these different countries have their own little radar networks and they need to talk to each other and get the data to uh to align. And so in Switzerland maybe the species that you're looking at is a much smaller subset because it's a much more specific type of type of habitat. Mm. So it's hard to compare the European insect population to the US.

Exactly. And one of the things that I'm working on right now is to try and uh compare across countries or understand how we can get these different uh types, these different radar networks. to provide data that we can align with one another so that we can do a large scale study in Europe as well. I am here for it. Come back and tell us about it. Absolutely, I'd love to.

Dr. Elska Tielens is an ecologist with the Swiss Federal Institute for Forest, Snow and Landscape Research. Thanks for talking to me today. Thank you. If this podcast has you on a high up in the clouds, you pick the strained metaphor. Um why not leave us a review wherever you get your podcasts? This episode was produced by Charles Burquist, I'm Flora Lichtmann and

Science Friday brings the joy of discovery to millions of curious listeners every week. When you sponsor Science Friday, you connect with a dedicated audience that values knowledge, exploration, and learning. These are folks who love getting into the details, who actively engage with ideas, and who value trustworthy information. Learn more at sponsorship.wnyc.org.