Science Friday - Gut Fungi, Olympic Challenges, Planetary Seismology. July 30, 2021, Part 2

Episode Date: July 30, 2021

Getting To Know The Fungus Among Us (In Our Guts) Your gut microbiome is composed of more than bacteria—a less populous, but still important, resident is fungi. Many people’s lower digestive tract is home to the yeast Candida albicans, the species implicated in vaginal yeast infections and oral thrush. But new research published in the scientific journal Nature this month suggests that Candida in the gut may also be related to severe cases of inflammatory bowel disease, or IBD. Candida comes in multiple forms: a single-celled, rounded yeast, and a multicellular, branched version, known as the hyphal form. The latter is capable of invading other cells, and is associated with tissue damage, like that of IBD. The research team writes that our immune system reacts to candida by targeting a protein found on that second, invasive state. Conversely, our bodies seem to leave the rounded, yeast form alone.  Better understanding what drives these distinct responses may provide clues to developing a vaccine that could help people with candida-linked health problems. And postdoctoral researcher Kyla Ost tells guest host Roxanne Khamsi that the relationship appears to be mutualistic—that is, the fungi themselves benefit from being managed in this way.  She explains the nuanced relationship she and her colleagues uncovered, and how uncovering more about gut fungi may bring new insights into the relationship between our microbial communities and our health.      COVID And Climate Change Collide At The Olympics The Tokyo Olympics have been underway for a week, with talented athletes competing at their peak. But this year, it’s hard to watch the Olympics without thinking about two of the biggest science stories of the summer: COVID-19, and the record heat and humidity athletes are facing as part of this year’s games. Holding the Olympics during a global pandemic is uncharted territory, and keeping the virus out of the games has been a huge logistical challenge. There are more than 11,000 athletes participating in this summer’s games, coming from 206 nations. Factor in the coaches, staff, press, and service workers, and that’s a lot of people to keep healthy. As if that wasn’t enough, Tokyo is experiencing extreme heat and humidity, consistently reaching 90 degrees Fahrenheit with humidity at about 80%. While the city has always had hot summers, they have gotten worse with climate change. Tokyo’s average annual temperature has risen by more than 5 degrees Fahrenheit since 1900, according to NASA. Athletes have had to take additional measures to keep themselves cool. To tackle these stories, guest host Roxanne Khamsi talks to sports writer Hannah Keyser, from Yahoo Sports, about the Olympics’ COVID-19 protocols, as well as her experience as a reporter covering the games in Tokyo. Then, Roxanne speaks with Scott Delp, professor of bioengineering at Stanford University and director of the Wu Tsai Human Performance Alliance, about athletic performance and safety.   What’s Shaking Below Mars’ Surface? You’ve seen the effects of earthquakes on our planet. The ground shakes, the earth trembles, and if a quake is strong enough, it can bring widespread damage and devastation. But it turns out that ours is not the only quaking planet around—there are quakes caused by geologic activity on Mars too. While Mars doesn’t have plate tectonics like Earth, other processes, from volcanic activity to planetary cooling, can cause tremors in the ground. Seismologists have been using these marsquakes almost like sonar signals through the planet’s interior to provide clues as to what’s going on below the Martian surface.   Several new papers based on the data from the Mars InSight lander were recently published in the academic journal Science. Bruce Banerdt, principal investigator, and Sue Smrekar, deputy principal investigator for the InSight lander, join guest host Roxanne Khamsi to talk about the results and how they compare to Earth geology. Smrekar also gives a preview of the planned VERITAS mission to Venus, which will attempt to deduce some of Venus’ geologic processes from orbit. Smrekar is principal investigator for VERITAS, which might launch in 2027. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Roxanne Camsey. Ira is away this week. Later in the hour, we'll talk about how science has a starring role at this year's Olympics, plus new research into earthquakes on Mars, though I suppose we'd better call them Marsquakes. But first, long-time listeners will know that the human gut microbiome is a favorite subject of this show. We're learning more every year about how communities of bacteria, viruses, and fungi operate in and on your body to both harm and benefit your health. And yes, you heard that right, fungi are part of that equation. And just as the community dynamics of the bacteria in our gut may have a role in our health, research is finding interesting relationships between our immune system,

fungi, and conditions like inflammatory bowel disease. Kaila Ost is a postdoctoral researcher in pathology at the University of Utah and a co-author of New York. And a co-author of New research on a fungus called Candida Albicans. Welcome, Kyla. Thank you, Roxanne. I'm excited to be here. Can you tell me a bit about which fungi are there and what they're up to? I mean, we're not talking about full-fledged mushrooms, for example, right? You're exactly right. When we think of the gut, microbial community, your mind automatically goes to the bacteria, which in all fairness make up the vast majority of the microbial community. But among this complex, community of microbes. There are fungal species. And of course, like you said, these are not

mushroom species. They are yeast species typically. And so what's a yeast? A yeast is a single-celled organism that grows typically in little circular buds. And under a microscope, they look very similar to the yeast that you think of that makes our beer and you use to make bread. These single-celled yeast species, while they are vastly outnumbered by the bacteria within the gut, are really important for host health. And the species you're looking at specifically is Candida Albacans, right? What is Candida up to? Yeah, so Canada Albucans is typically the most dominant or abundant fungal species in a human gut. Most of what we know about Canada is from its pathogenic potential. So we know that Canada is a normal colonizer of the human gut, but in people who have compromised immune systems, the Canada can overgrow and invade host tissues to cause infections, like thrush or vaginal yeast infections.

But recent research has demonstrated that Canada albucans and other Canada fungi can exacerbate inflammatory diseases like inflammatory bowel disease. And that is the sort of disease that we focused on in this. study. And you and your colleagues found that whether Candida Albuquins is harmful actually depends on what shape it took. Yeah, you're exactly right. So Canada and other fungi, in fact, are really fascinating because they're shapeshifters. And Canada Alacans is really famous for undergoing this morphological transition from growing as a single cell butted yeast to an elongated multicellular heifel form. And this is really important because the Haifle form of Canada is more pathogenic. So it's better at adhering to host tissues and invading host tissues.

Basically, what we found was that our immune system is really good at targeting and suppressing this hyphal pathogenic form of Canada. And we further showed that this Heifle form of Canada is much more pathogenic in a mouse model of IBD than the yeast form. And so the implication of our work is that potentially it's not necessarily just the presence of Canada al-Bacans, within the gut that is exacerbating disease. But it's the form that that Canada albacans has taken that may be important for disease exacerbation. Yeah, it's like a lot of shape-shifting going on with this Canada albicans. I didn't imagine all this stuff was happening in our guts. So like, what is our immune system doing to target that sticky type of Canada albacans?

What we found was that it's actually antibodies that appear to be specifically targeting this Heifel form and suppressing the Haifie within the gut. And so antibodies are immune molecules designed to target molecules, often on pathogenic microbes. And in the gut, it's actually quite fascinating because our gut immune cells make a lot of antibodies every day, even in the absence of infection. And these microbes within our gut, including Canada albuans, and other commensal species, sort of live their whole lives in an environment teeming with these immune molecules that are constantly targeting them. And so, yes, what we found is that these antibody responses are really important for targeting and shaping the Canada Albucan's biology

in such a way to suppress hyphy and pathogenic molecules on these fungi to potentially suppress their pathogenic potential. Can you kind of connect all this with the inflammatory bowel disease? This is really common gut disorder. So what our study is focused on is trying to understand how Canada Albucans is maintained in a non-pathogenic state in a sort of a healthy situation. And so the antibody responses that we found were not sort of specific or different depending on IBD status. But I want to emphasize that they were present in healthy people along with people with IBD. And so what we think this represents is a normal sort of homeostatic interaction between antibody responses and this commensal yeast that most of us carry around within the gut that actually

promotes its commensalism. By that, I mean, prevents pathogenic Canada from arising. Does the yeast form of Canada al-albicans actually help us in any way? Like, why would our immune systems leave it alone when it's in that kind of friendly form. That's a fantastic question. One that I and many others in the field are trying to answer. But I would say that there have been a number of really fascinating recent studies to suggest that Canada Albucans in the gut may serve a beneficial purpose. It might be beneficial in some way.

And particularly, Canada Albucaans is pretty immunogenic. So it's really good at getting in your gut and inducing strong immune responses without leaving the gut. so living in its normal commensal place. And researchers have recently found that these immune responses induced by Canada can protect potentially from other pathogenic microbes like bacteria. So there have been some clues to suggest that Canada in the gut may be beneficial. But yes, you're right. It depends on sort of the biology or maybe even you could think of the behavior of the

Canada in the gut, whether it has beneficial. a beneficial potential or pathogenic potential. So usually we have this picture of the immune system coming in to save us from invaders, but it sounds like what's going on with these fungi is a little bit more nuanced. Can you unpack that a bit? Oh, I'm so happy you picked up on that. It's the bit about our study that fascinates me the most. You're exactly right.

There's a complex and not very, it's not necessarily linear sort of interaction between our immune system and fungi or candid albuans in the gut. What we found ultimately is that these antibody responses are really good at targeting Canada abacans, but in fact they're not responsible for clearing or suppressing the total level of Canada within the gut. Instead, what appears to be happening is that these antibody responses are altering or sculpting the biology of the Canada population within your gut to suppress the sort of bad form of Canada within the gut. And the fascinating bit about this is that we discovered that Canada Albuquans itself appears to gain a fitness advantage from this immune sculpting. Oh my goodness. What that means is that the selection for these yeast cell types over the Heifie improves Canada's fitness for gut colonization.

Other studies have demonstrated that the yeast cell form of Canada, for some reason, does a whole lot of, better in the gut than Haifi. And our study demonstrates that antibodies may be helping Canada basically be the best commensal it can be, while also preventing sort of the damage that Canada could potentially cause. I mean, that's definitely a two-way street between our immune systems and the Canada albicans, it sounds like. I like to think of it as a communication that the Canada and the host are sort of moving towards a mutualistic interaction to maintain homeostasis. So we've talked talked a little bit about how this relationship can go wrong sometimes. And I know that in those situations, we have antifungals, but there's also rising antifungal resistance. So this antibody

response to Candida Albuquins that you found, can we use that somehow and harness it to make the disease less severe for people? Yes, that's exactly what we tested and what we think we've we've shown. We used a Canada Albucan's vaccine, which has been developed originally to prevent Canada Albucan's infections. And this vaccine is fascinating because it is, it's called the NDV-3A vaccine. It's designed to target just one type of adhesion molecule, a sticky molecule on Canada abacans that we found was also a target of these intestinal antibody responses. And so what we found was that this adhesin-based vaccine was really effective at preventing Canada from aggravating IBD in mice and suggests that this vaccination strategy could be a

potentially useful therapeutic to prevent this type of pathogenic interaction with Canada in people. This is fascinating, I have to say. We're all walking around with these communities of fungi and bacteria in our guts. And so I am curious still to know a little bit more about, are there any questions you have about how your immune system is interacting beyond what we already know? Like, is there anything you're dying to know about the immune system's relationship with all these living organisms inside of us? Yes, I have to admit something I think about all the time. I think there's many really important questions that we still don't understand about sort of immune responses and microbes. When we think of these antibody responses, we think of, you know, it being very linear in which the microbes induce the response, the response targets them and clears them. But now we're really understanding is that the commensal microbes within our gut are inducing these immune responses throughout our life, and we carry them throughout our life. And so what interests me is understanding how microbes, not just the commensal microbes, but also pathogens, sort of contend with this

mature immune environment that is always present and always changing. We don't know that much about how this immune environment sort of shapes the biology and the interactions with a host of different microbes. Well, I have to say, I'm really going to be thinking about all of this, and especially my immune system the next time I have a meal. So, you know, thank you, Kyla. That's all the time we have, but we really appreciate your joining us today. Thank you so much. Kyla Oost, postdoctoral researcher in pathology at the University of Utah in Salt Lake City. We have to take a break, but when we come back, we'll talk about two big sciencey reasons why the Tokyo Olympics are different from previous ones, COVID-19 and climate change.

We'll be right back after the short break. This is Science Friday. I'm Roxanne Kamsie. The Tokyo Olympics have been underway for a week now, and for the those of us who love seeing very talented people at the peak of their athletic abilities, it's a fun thing to watch. But this year in particular, it's hard to watch the Olympics without thinking about two huge science stories, COVID-19, and the record heat and humidity athletes are facing as part of this year's Olympic Games. A little later, we'll talk about how climate change affects athletic performance. But first, keeping COVID-19 out of the Olympics has been a huge logistical challenge. There are more than 11,000 athletes participating in this summer's games

from 206 nations. Factor in the coaches, staff, press, and service workers. That's a lot of people to keep tabs on in order to mitigate infections. Since we're a week into this experiment, let's find out how it's been going with my guest. Hannah Kaiser is a sports writer for Yahoo Sports. She's based in Brooklyn, but she's joining us from Tokyo. Hi, Hannah. Welcome to Science Friday. Hi, thank you for having me. So let's talk about COVID-19 protocols for athletes. What did they have to do before last Friday when the Olympics officially started? Well, one of the things they had to do was not show up if they're not competing right away.

So the IOC is limiting how long they can be in the village. So that's part of why we saw a really small opening ceremony. I think we also probably saw a really small opening ceremony in terms of athlete participation because there was no one to cheer them on. there's no fans, obviously. So you mentioned the 11,000 athletes. I think I've heard that there's somewhere like 79,000 support staff. So it's not just the athletes themselves that are showing up to Tokyo. It's people like me, the media. And I'm pretty sure they're right in line with what we did, which involved multiple tests, very precise amount of time out. So you had to take a test within 96 hours

of traveling, another one within 72 hours of traveling. It's an incredible amount of paperwork. Truly, like we had to submit these so-called activity plans that tell the Japanese government exactly where we're going to be all the possible locations in Tokyo and in these surrounding cities that we could be the first two weeks that were here. They had to be approved all the way up the chain all the way up to the sort of Japanese government level. For media, at least, once we're here, we're testing every day for the first three days. We have these apps on our phone that were having to check in every day, temperature, symptoms that's, sort of thing. They are trying to keep incredibly close tabs on everyone, which I'm not entirely sure how well they're doing that. I mean, I just, it's, it's so many people and they're testing everyone so often, and it's sort of hard to imagine that they're processing all of these tests and

actually keeping all this information somewhere. So what you're saying about testing is so intense, and one thing that comes to mind is vaccines. You know, vaccines are not widely available yet in many parts of the world. So does that mean that vaccines are not required for the athletes? They are not required for the athletes, not even for the U.S. athletes. And, you know, vaccines are fairly widely available back in the States. They weren't required for anyone. And not only were they not required, it doesn't get you anything. I mean, there's sort of, there are, the protocols are no different regardless of whether or not you're vaccinated. But that's true for both media and athletes. Wow. Okay. So are there rules for how the athletes are supposed to interact with the

other when they're not competing given given this COVID age we're in yeah they're not supposed to be interacting much at all i mean it certainly looks like they have more freedom in the village than we do as media and we cannot go to the village but they're interacting a little in the dining hall but you know there are these plastic barriers between every seat so you're even if you're eating with one other person you're on the other side of plastic they're they're being told to put on plastic gloves when they go into the dining hall which you know we're a year and a half into this we do know the science. And that's kind of just sanitation theater. I'm not sure that's actually doing anything to protect anyone from COVID. Well, is there a lot of masking going on there. There is an incredible

amount of masking. Yes. There's an incredible amount of masking and an incredible culture of policing masking. That's, I think, widely within Japan and certainly within the Olympics. I mean, even the IOC had to update their official protocols just to let athletes take their masks off for something like 30 seconds on the podium to take a photo. Because originally it They were supposed to, you know, wear their masks as any time they're doing anything other than competing or training. So one of the things that actually also was surprising to me is to hear that some of these athletes have actually tested positive for COVID since arriving in Japan.

How does that reflect on these policies, all the things that you've just told us about? Is there room to be even stricter with some of these policies? You know, I'm not sure that there is room, which is sort of the whole problem with all of this. I mean, you know, they wanted to hold these Olympics despite the rate of cases in Tokyo being on the rise, the rate sort of around the world. We're seeing new variants. And I think that this amount of positive tests, I don't think you could sort of crack down even further. I think that that's actually sort of an important thing to keep in mind is that we are seeing positive tests. And I don't know that it's necessarily because the athletes are breaking protocol.

We haven't had any sort of huge scandal. Oh, somebody went out to party in Tokyo. I think it's just, you know, you bring 80. 90,000 people together and not all of them are vaccinated and you're going to have some false positive, real positive breakthrough tests. I mean, there wasn't a way that you could put in a sufficient number of protocols to ensure that this was a totally 100% safe process. So what are you going to be keeping your eye out for in this final week of the Olympics COVID-wise? I think there's really two things. One is the sort of community rate in Tokyo. I think we've seen some

indications that cases are continuing to rise. And that's a real problem. I mean, you know, whether or not the Olympics should take place, and this is true sort of of all sports leagues that are happening in a pandemic, you're going to get a certain number of positives if you're testing hundreds or thousands of athletes. But what you don't want to see is that that's prolonging the pandemic or worsening the pandemic in the community that's sort of foisted upon. So I think in terms of evaluating whether or not these Olympics should have happened or whether or not it's a huge mistake or a failure. That's really going to come from what their rates are like in Tokyo at large. And then beyond that, because people are testing positive, what effects that has on the

competitive integrity of the sports we've seen athletes have to drop out or have to get replaced at the last minute, you know, somebody could test positive right before a gold medal match. And that we would start to feel that, you know, not only are these maybe a bad idea, they're also kind of a farce if they're undermining the athletic competitive integrity as well as the safety of the city. Yeah, well, definitely everything that you've said is making me feel like the stakes are even higher than any regular Olympics. But, you know, thank you so much, Hannah, and I want you to stay safe out there in Tokyo. Thank you. Hannah Kaiser is a sports writer for Yahoo Sports. She's based in Brooklyn, but is currently in Tokyo covering the Olympics.

Now to the other big science story of this year's Olympics. Tokyo is hot. The city has consistently hit 90 degrees Fahrenheit during the games, with relative humidity hovering around 80%. While the city has always had high heat and humidity in summertime, things have gotten much worse with global warming. According to NASA, Tokyo's average temperature has gotten five degrees hotter since 1900. If you're one of the elite athletes in this year's Olympics, that means you've got to take measures to keep yourself cool and safe, because trying to hit your athletic peak at the right time is already a complicated process, even without extreme weather. Here to talk with me about athletic performance and safety amid extreme heat in this year's Olympics

is my guest. Dr. Scott Delp, Professor of Bioengineering at Stanford University, and Director of the Wu-Sai Human Performance Alliance. He's based in Palo Alto, California. Welcome to Science Friday. Great to be here. Thanks so much for having me. So, Scott, let's start with the idea.

of an athlete peaking at the right time. What does that mean exactly? And like, what are the factors that go into making sure that an athlete peaks at the right time? It's a great question. And there are a lot of factors. You want to peek physically, emotionally, mentally, so that you can really perform your best. And to do that, you need to train hard.

But the key is to not over-train, not peak too early. Because overtraining can literally leave you exhausted and unable to perform even near your peak. So it's challenging because we vary between individuals and we vary between sports. And there's not super strong science to guide this. So it's really a challenge for athletes as they approach the Olympics. You got to find that sweet spot. But what happens if an athlete pushes themselves too hard biologically? So injury is the most common problem.

When we overload, we can injure muscles, tendons, ligaments, and they take a long time to heal, a short time to injure, but a long time to heal. And you might be just emotionally exhausted or not have the ability to focus. And, you know, competing is not just a physical event. It's also a mental event, too. So it really is challenging to sync all these up. I would like to talk about the weather. I know that talking about the weather is sometimes a conversation filler, but in this case, it's actually something that's of huge consequence, right? There's extreme weather conditions athletes are facing in this year's Olympics. Not only is it very, very hot in Tokyo, there's also very high humidity. So how do these factors affect the human body? They affect the body profoundly. And I think you pointed out something really important.

that it's not just hot, it's also humid. And there's a big difference when we have both of those things. Humans cool ourselves by evaporating sweat from the surfaces of our bodies. And we do that actually quite well. We have lots of surface on which we can sweat. And when we have that liquid on the outside of our body and it evaporates, that takes a lot of energy and that sucks the heat out of our body. The problem is that it's very difficult to do that when there's

humidity. We sweat, but the sweat doesn't evaporate. So we're not shedding heat like we would if it were hot and dry. And in Tokyo, it's hot and humid. So we're sweating, but the sweat isn't evaporating. So we're not cooling ourselves very well. And when that happens, it actually can raise the core temperature of your body. And that can be quite dangerous. You see some athletes collapsing because of heat exhaustion and even heat stroke. You know, we're humans and we're pretty ingenious sometimes. And I think what we've seen at the Olympics is there are some athletes using like cold vests or ice packs before and during competition. Are there other ways that heat and humidity can be mitigated in terms of its effect?

There are. You know, it's interesting. The best radiators in our body are our hands and our feet and our head. So cooling our hands or cooling our feet is the most effective way. to drop your core temperature. So if you put your hands or feet in an ice bucket, that works really well. I've seen people putting ice on their wrists and that can be effective, but that's basically cooling the pipes going to the radiators. The radiators are the hands and the feet. So you really want to cool the radiators.

That would be very effective. On the ice vests, if they're tightly fitting and really transferring a lot of heat out of the body into the ice of the vest, that can be effective. But you have to watch out if you're just cooling the skin and shutting down the capillaries there, the small blood vessels that are there to help you shed heat, you actually might continue to raise the core temperature while you're cooling the skin.

So you have to watch out and make sure you're hitting the right balance. You know, it reminds me I went to tennis camp, which is hilarious if you've ever seen me play tennis because I cannot. And I remember the very wise aged, the head of the camp telling us if we ever got hot on those courts to go run our wrists under cold water. So are you debunking what he told us back then many decades ago? Well, so it can work, but it doesn't work as well as dunking your hands in cold water or dunking your feet in cold water. That's where your body really radiates a lot of energy and you can cool yourself. if you cool the blood in your hands, then when it goes back to your heart, then you spread that

cooled blood all over your body. I'm Roxanne Kamsley, and this is Science Friday from WNYC Studios. So are there any summer sports, because there are a lot of them at the Olympics, that require more heat prep than others? There are long duration sports like the triathlon, the marathon. If you're out there on the soccer field for an hour and a half or two hours, they really require heat training. And training in heat prior to then trying to perform in heat, it really works.

There are a number of adaptations that come into play that if you train in heat, you'll be better adapted and better able to perform, especially for those long duration events. If it's a short duration event, it might affect your performance, but it's not going to be dangerous. Yeah, I can imagine, especially if you're running a marathon or something like that, that you've just got to be super careful about getting too hot. One thing they are doing, I've seen this in the marathon, and I think it's a good idea. Instead of drinking water, they're drinking slushies. So there's a little bit of ice in there.

And to put that ice into your core, and then your body has to melt the ice. So the energy associated with a melting of ice can really dissipate a lot of heat. So I actually have seen that, and I think it's a really good idea in these high heat. situations. I think we're getting very close here to a scientific endorsement of ice cream. But I'll move on to the last couple questions here, which is, you know, we know that athletes are just reaching heights and speeds that we've never seen before. They're really showing us all the humans can do. But, you know, climate change is getting worse and worse. We're seeing the planet warm. So is it getting harder than ever to be an elite athlete, given the warming planet?

Well, heat certainly can degrade our performance in a place like Tokyo during July and August with high heat and high humidity. It's not only can degrade performance, but also be dangerous. So I think one of the things we have to think about with global climate change is when we hold these events and where we hold these events. Because holding them in places that are high heat and high humidity, we really shouldn't be. exposing athletes to that kind of risk. So I think that's going to be an important consideration going forward for these global events as where and when we hold them. Wow, that's a fantastic point. So we're talking about the Olympics here, but heat and humidity are also going to impact you and me, right? So given that, is there something that we can glean from studying the science of

performance that might help us? It really can. You know, almost all of what we know about health is from studying diseases. And we've just launched this new scientific partnership called the Human Performance Alliance, and we're taking the opposite approach. We're studying peak performance with the goal of enabling all people to achieve optimal health and well-being.

You can imagine, for example, to study how an athlete can cool themselves, they're actually quite trained and very good at it, but there are individuals that as we age, for example, we aren't as good at shedding heat. So to see the biological mechanisms that athletes use to cool themselves during physical exertion and understanding that can actually help all of us to have a better approach to maintaining our body temperature.

So I think what you're saying is we're going to see slushies for seniors? That's not a bad idea, actually. You know, it's a big problem when cities get hot. Well, I hear the ice cream trucks coming in. Anyway, that's all the time we have for now. I'd like to thank my guest. Dr. Scott Delp, Professor of Bioengineering at Stanford University and Director of the Wu Sai Human Performance Alliance.

He's based in Palo Alto, California. Thanks so much, Roxanne. It's been great to be with you. After the break, we're learning about Marsquakes. Stay with us. This is Science Friday. I'm Roxanne Kamsi. You've seen the effects of earthquakes on our planet,

the ground shakes, the Earth trembles, and if it's strong enough, damage and devastation. But it turns out that ours is not the only quaking planet around. There are Mars quakes, too. Sysmologists have been studying these quakes on Mars, and they're giving scientists exciting first clues as to what's going on below the Martian surface. Several new papers based on the data from the Mars Insightlander were recently published in the journal Science. Joining me now to talk about that mission and what it is revealing is Bruce Bannert. He's principal investigator for the Mars Insight Mission. And Sue Smirkar, she's deputy principal investigator for the Mars Insight Lander

and the principal investigator for the planned Veritas space probe to Venus. They're both based at NASA's Jet Propulsion Laboratory in California. Welcome to Science Friday. Hi, how are you doing? Great. Sue, it's good to have you too. Thanks. I'd like to kick it off with you. Can you describe these quakes for us? Like, how big are they on the Richter scale? Well, these are actually fairly small quakes by our kind of Earth standards. These are less than about magnitude four on the magnitude scale. And that's a quake that you would feel pretty well. You'd feel it shaking you around if you were within, oh, 10 or 20 miles of the epicenter on the Earth, or on Mars for

that matter. But if you got much farther away from that, you probably wouldn't feel very much. So these are not very big quakes, but Mars is a small planet, so they don't have to go very far to get through the inside. And we're able to use these very small quakes to probe deep into the planet. You and Sue and others were detecting these quakes with the seismometer from insight. Can you tell me a little bit about how you use the technology to find out what's going on inside the planet? Well, the science of seismology is basically taking the wiggles on a seismic ram, which are the displacement waves that come through the planet, and using them to pull out the information that they've picked up as the waves that traveled through the planet. So when fault breaks on the other side of the planet, it sets up vibrations, and those vibrations move through the planet, much like sound waves, move through the air.

And as they move through the planet, the properties these ways are affected by the materials they move through. They can get reflected off of boundaries. They can get refracted just the same way as light is refracted in a prism. As they go from one kind of material into another kind of material, they get attenuated. The waves die out. They lose some of their energy as they go through materials. And some materials attenuate them more than others, especially hot materials, which are a little bit softer, tend to kill off the waves more quickly than cold brittle materials.

And so all these things are basically, they're pieces of information about the deep inside of the planet that get encoded into the signal. And so we've used things like the travel times of different ways to infer the different paths that they've taken. We look at their frequency content. We look at their polarization. There are just a myriad of different waves that you can attach. these signals with the same kinds of processes that have been developed for, you know, radar, radio and things like that, and even acoustic recordings to, you know, pull this information out

of our seismograms. That's amazing. And you've been working on this lander for around a decade. Is it as straightforward as taking an Earth-size monitor and getting it to another planet? Nothing in space is straightforward. It's actually a super complex and difficult. endeavor to get something that works on the earth and make sure that you can actually do the same thing on the very harsh surface of another planet like Mars.

So it sounds a little tricky. You've got to package it up and somehow deliver it in a way that's unique. Right. I mean, first of all, you have to get it on the ground on another planet. And it's hard enough just landing on Mars. I'm sure you've seen the videos about how difficult and how hair-raising it is to land on Mars. But once you've landed on the planet, your instrument's sitting on top of your lander, which is about a meter away from where you'd like to be, which is on the ground.

And so we had to include a robotic arm that would pick it up off the deck of the lander, place it on the ground, and then pick up another shield to put over it to protect it from the wind. So that was a pretty complex operation in and of itself. And then we had to take it. shielded against temperatures. On Mars, the temperatures can go up and down by more than 100 degrees

Celsius. And you know how things expand and contract with temperature. When we're measuring displacements of the ground, vibrations of the ground, some of those vibrations are no larger than the size of a hydrogen atom. So you can imagine even small temperature variations down to thousands of a degree can make signals on our seismometers. So we have to, we have three different layers of thermal insulation. We have a windshield to keep the wind from blowing on it. We do all kinds of things to cut down on other sources of vibrational noise so we can see these extremely small vibrations that have traveled for thousands of kilometers through the planet. Well, this does not sound easy-peasy, but I'm glad that you guys figured out the robotic arm and all those different

protections. Fantastic. So Sue, can you tell us a bit about what's going on with these quakes? On Earth, as far as I understand, there's tectonic plates pushing into each other, but that's not the case on Mars, right? Right. No plate tectonics on Mars. But that doesn't mean that there isn't tectonics. So, you know, on Earth, we have our plates that are sinking into the mantle and sliding past each other and colliding to form mountain belts. So we have, you know, measurable velocities of these plates, the surface, it's constantly causing geologic activity and basically all of our earthquakes. But on Mars, it's a so-called single-plate planet, but that doesn't mean that there's not fracturing, deformation, faulting, volcanoes. Now, of course, most of the

surface of Mars is quite old, billions of years old, but there are still a few places on the surface that are recently from a geologist standpoint active. And one of the places is actually pretty close to our lander, about a thousand miles from our lander. And it's called a Cerberus Fossi. And it's got these 500 kilometer, a few hundred mile long fractures that are related to volcanism. There have been flows that have come out, you know, in the past few million years. So for Mars, that's super recent. And so there's still geologic activity on Mars. And as I understand, the planet is cooling as well, right?

That adds something to the whole picture. Absolutely, yeah. Yeah, in fact, you know, before we sent insight to Mars, people did calculations to try to estimate the amount of fracturing or faulting that would be occurring due to that cooling of a planet. I mean, all planets are cooling. and Mars is perhaps dominated by that process of cooling. And maybe one of the interesting things we discovered is certainly some of the overall

activity is due to cooling, but perhaps a surprising amount is coming from these particular fractures. And the other thing that we found is that some of the other fractures that are pretty recent on the kind of the other side of the planet, we're actually, because Mars has a much bigger core, we're actually in the shadow of the core with respect to the other side of the planet and how the seismic waves travel through the planet. So we can't actually pick up all the quakes from some of the places that we think should be tectonically active on Mars. So yeah, we have the cooling and fortunately have this great local seismic source too. How is this different from

what's here on Earth, what we know about the inside of our planet? Well, it's, As Sue was talking about how Mars is cooling off, and actually the way a planet cools is really fundamental to its geology, to the features on the surface and the way they evolve. On the Earth, the planet loses its heat mostly through the process of plate tectonics, when hot material rises at mid-ocean ridges, and as it spreads out, it can cool itself through the floor of the ocean. And that's a very efficient way of cooling a planet, and it lends itself to a lot of dynamics, a lot of action. There's a lot of motion, a lot of forces that are built up. And so we have a very active planet with lots of seismic activity, lots of volcanic activity, and accompanying hydrothermal activity, and so forth. On Mars, since it only has one plate, essentially, there's no plate tectonics because we have one single plate covering the entire planet.

it cools more slowly. It cools by conduction through the surface. And so most of the geologic activity is dominated by either localized volcanism or in some cases there's some rising and falling of that one plate as hot plumes from deep in the mantle rise up and can push up on the bottom of the crust or maybe pull down where they descend back into the mantle. And so it's a very different kind of set of forces and processes that occur on Mars. And that's, to some extent, that explains a lot of the differences in the serpent's features that we see on Mars compared to the Earth. Do all the rules that we've learned for geology on Earth necessarily hold true on Mars? Are these things that are surprising you both? I would say for the most part, you know, the same rules apply. The really

interesting part for us as scientists is when you have the small deviations, not necessarily from the rules, but from the way the rules are applied. And so, you know, you have the same physics, the same, you know, physical laws, the same general geology. But the details, that's where, that's where the really interesting stuff is, you know. For example, on Mars, the crust is a little bit thinner than it is on the Earth. The core is a little bit bigger and, you know, relatively speaking. And those differences between the Mars and the Earth are due to differences in either the starting conditions of the planet's formation or in the path of evolution that it took from those very earliest years till today. And so we're looking at those differences and using them to fine tune our models for understanding how these planetary processes work. I'm Roxanne Kamsie, and this is Science Friday from WNYC Studios.

I'm talking with Bruce Bannart and Sue Smarkar about investigating the seismology of other planets. As I understand, you're working on plans for the Veritas mission to Venus, which could also try to figure out things about the geologic processes working on that planet. But from orbit, so how do you do that? Well, we're going to take data from a couple of different instruments. We're going to get topography at high resolution. radar images, you know, for Venus, it's shrouded in this thick cloud layer. So anything that we do from orbit has to be able to penetrate through that cloud layer. So we use radar to do that. And we also have a spectrometer that sees the surface around one micron, like a thermal part of the spectrum.

And with that, we're able to look for things like variations in the iron mineralogy that tell us that a volcanic eruption has been there recently. It hasn't yet chemically equilibrated with the atmosphere. We can also look for actual active eruptions, but you have to be super lucky to see active eruptions because on Venus, on Earth, everywhere, basically when a super hot lava comes to the surface, it starts to form a crust very quickly.

And so it's hard to see that thermal signature from orbit for more than a few weeks or so. So do you have a timeline? for Veritas? Well, we're negotiating with NASA headquarters on exactly when we're going to launch. We're hoping it will be towards the end of 2027. Great. Both of you have said some really interesting things. And what I'm curious about is what would you both hope to learn from either of your missions? Well, in terms of insight, we've really, with these three papers, kind of hit on the main goals of the mission. I mean, this is really what we started out, you know, 10, 15 years ago to do was to delineate the size of the core, the thickness of the crust, and the structure of the mantle of Mars.

On that level, you know, we could sit on our laurels now and say, you know, we're done. But of course, you know, we're still alive on the planet. We're still alive on the surface, taking seismic data as we speak. And we'd like to, first of all, you know, refine those measurements, get them down to, more precise values. And we're looking at new things. We're looking at the possibility that seismic activity on Mars might have a seasonal variation, which is we have some hints of that now, which would be very strange and very different than what we see on the Earth. There's lots of different weird kinds of quake signals that we're seeing that we don't understand yet. So there's a lot to

still to understand about Mars. Well, I'll tell you the things that I'm hoping to learn about Venus. You know, for me, the fascinating thing about Venus is that it is so similar in size to the Earth, but it doesn't have plate tectonics. And, you know, we've been talking all about how planets lose their heat and how what's going on inside with the loss of that heat affects what's going on on the surface. You know, Earth has plate tectonics. Mars has these big volcanoes and still has faulting and so forth. Venus is this crazy place. It has a young surface. You know, it's somewhat similar in age, the surface of the earth. But it, and it's so big, it has this giant amount of heat, this heat engine that should be churning and producing something like plate tectonics, but it doesn't. So the big question for me is how is it operating? You know, what's the process? we think that it may have a lot to do with a volcanism.

You know, there's just 80% of the surface is covered in volcanoes. And so maybe there's some kind of intermediate process where it loses a lot of heat through volcanoes, it never erupt in the surface. And the other thing that's truly fascinating to me is that we believe it has subduction zones where one of these thick plates is sinking into the mantle. and that is how everyone thinks plate tectonics started on the earth. You know, Earth didn't start out that way. It didn't form with plate tectonics.

It formed with a single plate. So this huge question is how does plate tectonics start? And that crust is like billions and billions of years old. So we have little data to actually tell us how the Earth made this massive transition to plate tectonics, which is so, you know, dominated the evolution of the Earth. But on Venus, we think we can study the process of subduction occurring today and to be able to see how a planet maybe starts down the path of plate tectonics to me is super fascinating. Well, as our planet is turning, we've run out of time, unfortunately. But Bruce Spanner, thank you so much.

Sue Schmerkar, thank you so much. Oh, you're very welcome. I'm really thrilled to be able to talk about this. Yeah, a pleasure. Thanks. Bruce Brannert is Principal Investigator for the Mars Insight Mission, and Sue Smirkar, she's Deputy Principal Investigator for the Mars Insight Lander and the principal investigator for the planned Veritas Space Probe to Venus. If you missed any part of this program or would like to hear it again, subscribe to our podcasts or ask your smart speaker to play Science Friday.

Every day is now Science Friday. Say hi to us on social media, Facebook, Twitter, Instagram, or even, email us. The address is SciFri at ScienceFri.com. Send feedback and tell us what you'd like us to cover, too. I was back next week. I'm Roxanne Camsey.