Listener Questions #25

Daniel and Kelly answer questions about kissing bugs, magnetic fields in the Sun, and microbiomes in space. See omnystudio.com/listener https://omnystudio.com/listener for privacy information.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Daniel Whiteson?

  This is an iHeart Podcast. Guaranteed Human.

• 0:04Speaker 01

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• 1:04Speaker 03

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• 1:19Speaker 04

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• 1:42Kelly Weinersmith?

  A new deadly bug has been found in the state for lovers. Should my family and I be quaking under our covers?

• 1:50Daniel Whiteson?

  If Maxwell was right, then magnetic field lines shouldn't ever snap. But field lines break in the sun, so was Maxwell full of...

• 1:58Kelly Weinersmith?

  Oh!

• 2:01Kelly Weinersmith?

  When Daniel's wife comes on the show, she often talks about poop, which got me thinking of microbes in space. So, what's the scoop?

• 2:10Daniel Whiteson?

  Whatever questions have been keeping you up at night, Daniel and Kelly's answers will make it all right.

• 2:16Kelly Weinersmith?

  Welcome to Daniel and Kelly's Extraordinary Universe.

• 2:32Daniel Whiteson?

  Hi, I'm Daniel. I'm a particle physicist and I wish I'd heard this episode before I visited Virginia.

• 2:37Kelly Weinersmith?

  Oh, come on. I'm gonna note that the thing I'm gonna talk about is a problem for California, too. So, watch it. Hello, I'm Kelly Weinersmith. I study parasites and space. And this might be the first episode where we talk about parasites and space for me. So, we've got it all for me.

• 2:56Daniel Whiteson?

  And reasons to not visit Virginia.

• 2:58Kelly Weinersmith?

  Or California.

• 3:01Daniel Whiteson?

  We'll have to work in some cannibalism and then it'll be the full suite of DKU checkboxes.

• 3:05Kelly Weinersmith?

  That's what we're gonna talk about poop. So, we already know we've got that taken care of.

• 3:10Daniel Whiteson?

  All right. So then, Kelly, my question for you is, on average, how much poop does an adult human ingest accidentally in their life?

• 3:17Kelly Weinersmith?

  You think I've just got that kind of information, like, ready to share with people? I feel like this is less a question and more some insights into what kind of person you think I am. I have no idea, Daniel. It's probably a lot. You're actually, your wife seems like she would know. Do you know the answer? Was this a quiz?

• 3:35Daniel Whiteson?

  It's not a quiz. I do not know the answer. But last time, you were very happy to talk about the butt-to-mouth pipeline, or whatever you called it.

• 3:43Kelly Weinersmith?

  Poop-to-mouth. Poop-to-mouth.

• 3:44Daniel Whiteson?

  Poop-to-mouth. There you go.

• 3:45Kelly Weinersmith?

  Yeah. I mean, let's just say that a lot of poop-to-mouth transmitted diseases are very common. So, the answer has to be a lot, you know? It's gotta be a lot.

• 3:57Daniel Whiteson?

  I'm just wondering, what are the correct units even for describing it? Are we talking kilograms, metric tons, micrograms? Just like, what are we looking at here? If you looked at a pile of all the poop you accidentally ingested in your life, how big would it be?

• 4:10Kelly Weinersmith?

  Oh, gosh. Gosh, I hope it's grams and not pounds or kilograms. I guess I'll keep the same units. I hope it's grams and not kilograms, but who knows?

• 4:19Daniel Whiteson?

  There you go. Things to look forward to. And that's just a little taste, ha, ha, ha, of what you have to look forward to on today's episode. Exactly. Today, we're answering questions about things people are curious about, things they wonder about, things they desperately need to know the answers to, but can't. Can't find satisfaction on the internet, including ChatGPT. So they write to us and you are also very welcome to write to us. And please don't ask your physics questions to ChatGPT. It doesn't know what it's talking about. Instead, write to us to questions at danielandkelly.org. We will give you a real answer from real humans that reflects real physics or biology.

• 4:56Kelly Weinersmith?

  Plus poop jokes.

• 4:59Daniel Whiteson?

  Actually, I bet ChatGPT could do some good poop jokes.

• 5:02Kelly Weinersmith?

  Yeah, I don't know. I've asked it to, I asked it to do 10 jokes about parasites. And I incorporated that into my speech as president of the Hematological Society of Washington, and they weren't very funny. I gotta say, it wasn't very good.

• 5:16Daniel Whiteson?

  All right, well, let's get right into it. Our first question comes from Zach and it's a question about a disgusting disease slash parasite. Yay.

• 5:25Kelly Weinersmith?

  And I gotta say, I'm, you know, Zach, I'm a fan of for a variety of reasons. One of, he found our podcast through MSNBC. So he's been a longtime Wiener Smith supporter. And he was the first one to refer to our audience as the extraordinaries, which I have absolutely stolen from him and use regularly.

• 5:42Daniel Whiteson?

  Because our audience is extraordinary.

• 5:44Kelly Weinersmith?

  Absolutely. Yes, I adore the extraordinaries. And so Zach is an extraordinary and let's hear what Zach had to ask.

• 5:51Speaker 06

  Hey there, extraordinaries. This one is definitely for Kelly. I just saw a headline about a deadly disease being spread in Virginia by something called a kissing bug and that the disease is some kind of parasite. So I'm wondering if you, as a Virginian, should be worried. Should I be worried? Looking forward to learning more, I think.

• 6:12Daniel Whiteson?

  All right, Kelly, tell us all about this. And everybody, stop eating your breakfast or lunch or whatever it was.

• 6:19Kelly Weinersmith?

  I mean, probably anytime I open my mouth to say something, you should do that. But all right, so the reason you worry about kissing bugs is because kissing bugs can transmit a disease called Chagas disease.

• 6:31Daniel Whiteson?

  Well, what is a kissing bug to start with? And why is it called a kissing bug?

• 6:35Kelly Weinersmith?

  Gosh, why is it called a kissing? So there, there are these bugs that are, you know, like maybe about the size of a quarter. In Latin America, they tend to live in houses like wedged into cracks in the walls. They're called kissing bugs because they tend to bite on your face. For example, around your lips and stuff.

• 6:48Daniel Whiteson?

  So you don't kiss the bugs. The bugs actually keep you from being able to kiss other people because you have these gross bug bites on your lips.

• 6:54Kelly Weinersmith?

  I mean, it depends on who you are, you know? No judgment.

• 6:59Daniel Whiteson?

  If that's your thing, all right.

• 7:02Kelly Weinersmith?

  So, but, but so what you really have to worry about with these bugs is that they can be infected by a disease called Chagas disease. And this is a protozoan, it's unicellular. We were talking about malaria a while back, and malaria is also a unicellular protozoan parasite. They both live inside cells. So malaria lives inside our blood cells. Trichinazoma cruzi, which is the parasite that causes Chagas disease, can live inside things like muscle cells, and your heart is a muscle, for example, and that, that's going to become a problem. So what happens is a kissing bug bites you, usually while you're sleeping, because they're, they're active at night. So it can bite like-

• 7:44Daniel Whiteson?

  Wait, they're crawling on your face at night while you're sleeping and biting you near the mouth?

• 7:48Kelly Weinersmith?

  Yeah.

• 7:49Daniel Whiteson?

  Oh, no.

• 7:50Kelly Weinersmith?

  Yeah, I know.

• 7:52Daniel Whiteson?

  Virginia is for lovers.

• 7:54Kelly Weinersmith?

  Hey, hey, okay, all right, you know what? Back up. Where do you find kissing bugs? In 29 states in the United States. So if you drew a line, maybe like three quarters of the way up the United States, all the states below that line have kissing bugs, including California. And I would bet you that California has a higher caseload than Virginia does, for reasons we'll get to later. So watch it. I'm getting saucy here.

• 8:21Daniel Whiteson?

  I was just saying Virginia's for lovers. I don't know what you're going off about here.

• 8:25Kelly Weinersmith?

  I saw your face, I knew what you meant.

• 8:28Daniel Whiteson?

  So you're sleeping peacefully, dreaming of vacations in Southern California, and some bug is crawling across your face and biting you on the lips, and inside of it, it's got this protozoan?

• 8:38Kelly Weinersmith?

  Yeah, right. And so when you get bit by a mosquito that has malaria, the virus essentially gets injected into you with the saliva. But here, what happens is the parasite takes a really big blood meal, and it fills its body up so much that it expels its feces.

• 8:54Daniel Whiteson?

  Oh.

• 8:55Kelly Weinersmith?

  I know, I'm so sorry, everybody. And then, and then when you wake up in the morning, the spot where you got bit itches, and so you scratch, and you scratch the feces into your wound, and that's how you get infected. Or maybe you rub your eye and you- Scratch the feces into your eye and that's how it gets in. And so

• 9:11Daniel Whiteson?

  I know my role here is to like digest this and repeat it, but I really just don't even want to say these things coming out of my mouth. That's really repulsive. Oh my gosh. All right.

• 9:21Kelly Weinersmith?

  It's pretty unpleasant. And there's some other routes that you can apparently get it. Like if you live in areas where there's loads of these insects and they happen to get like ground up into your food, you can get the parasite by ingesting it. Mom can transmit it to baby if she gets it when she's pregnant. Blood transfusions, but in the United States, we check blood for Chagas disease. So that shouldn't be happening here.

• 9:42Daniel Whiteson?

  So the parasite comes through the feces of the kissing bug, but that's different from the mosquito, right? When the mosquito takes its blood meal, the parasite goes like down its little straw, right?

• 9:52Kelly Weinersmith?

  Yep, exactly. So like if you, you know, if your partner woke up and looked at you and was like, you just got bit by a kissing bug. Hold on. And they get like an alcohol wipe and they swipe away from where you got bit, then you could make sure you got no feces in your wound and you'd probably be okay. But usually what happens is you wake up groggy and it kind of itches. So you rub your face and you rub it in there.

• 10:14Daniel Whiteson?

  If your partner wakes up and you have bug poop on your face and their first instinct is like, I'm going to take care of this for you. You have a nice partner.

• 10:21Kelly Weinersmith?

  What, what do you think they should do?

• 10:24Daniel Whiteson?

  No, they should take care of it for you. But if instead they're like, oh my God, that's revolting. Get out of bed.

• 10:29Kelly Weinersmith?

  But okay, so you might be imagining like a human sized turd.

• 10:36Daniel Whiteson?

  I wasn't until you said that and now I am. Thank you.

• 10:40Kelly Weinersmith?

  Sorry. But no, this is like a tiny little speck. Like you might not, it's not going to be obvious. Your partner's not going to

• 10:48Daniel Whiteson?

  That's okay. Yeah. It's a tiny little speck of poop on my face. That's no big deal. Thank you. Oh yeah. I feel great about it now. Yeah.

• 10:56Kelly Weinersmith?

  All right. Well, hold on for a later episode where we talk about the mites that are living in your eyebrows that are pooping on your face all day. So, you know, you don't always see it.

• 11:03Daniel Whiteson?

  All right. So it gets into my blood because I've scratched this bite on my face and rubbed that tiny little dainty bit of poop into the bite. And then what happens to me?

• 11:13Kelly Weinersmith?

  All right. So, early symptoms are kind of nondescript things. You can have like a fever, loss of appetite, diarrhea, vomiting, enlarged lymph nodes, fatigue. But most people will present no symptoms. One obvious symptom is that there's this thing called Romagna's sign, and I'm sorry, I'm sure I mispronounced it, which is what we all have come to expect from me, which is a swelling around like the eye or the part of the face where you got bit by a kissing bug. And so if you get that, then you should like immediately go to the doctor and be like, I've got chagas. And they have anti-parasite treatments that you can get. And so if you've got this swelling, you should go in right away and get the parasite

• 11:53Kelly Weinersmith?

  wiped out. But what really becomes a problem is if you don't catch the parasite early on, it becomes much harder to treat. And what the parasite does is it's living in cells. And it's replicate, I know, it's replicating in your cells. And every once in a while, it will kill the cell as it breaks out, and your body will produce inflammation around the area where the parasite is living. And so for, you know, some people who have this parasite for decades, they'll start to get enlarged hearts from like the inflammation, and they can have heart failure that can result in death, or they can have digestive problems. I think the parasite also lives in like the cells in your digestive tract. And so you can get enlarged esophagus, enlarged colon, or you can have trouble eating or

• 12:36Kelly Weinersmith?

  using the restroom. And in these cases, it's much harder to treat the parasite. Like, you can give some treatment to try to slow the rate at which it's spreading to the other cells. But once it's firmly established in your cells, and they're like, safe inside your cells, it can be pretty hard to combat. And in that case, you are mostly just trying to reduce the symptoms associated with having an enlarged heart or an enlarged colon and stuff like that. So, should I worry?

• 13:03Daniel Whiteson?

  Yeah. Don't you worry anyway? Whether or not you should.

• 13:07Kelly Weinersmith?

  That's right. I worry about everything.

• 13:10Daniel Whiteson?

  Exactly.

• 13:11Kelly Weinersmith?

  And two states that have, you know, more Chagas disease than most of the rest of the United States include Texas and Florida. And for a while I lived in Houston. And so I did a bunch of research because I had a young daughter and I was worried we were gonna, you know, all get Chagas disease. And I convinced myself that I personally don't have to worry much. Here's why.

• 13:31Daniel Whiteson?

  What, you've done an internet deep dive that actually assuaged your worries? Doesn't always just inflame your worries?

• 13:37Kelly Weinersmith?

  You know, I actually feel like for people who worry about parasites, the more you learn about them, the less you worry because it, a lot of them have like very clear paths to infect people. And once you know, that gives you the power to avoid them, or at least to understand what behaviors are risky and what aren't. So yes, in this rare case, I decided I'm not gonna worry.

• 14:00Daniel Whiteson?

  And deciding not to worry always makes it possible to not worry, right?

• 14:03Kelly Weinersmith?

  Oh, no, those are different things. Those are different things.

• 14:08Kelly Weinersmith?

  What I do worry about, though, is most of the people in the United States who have Chagas disease are people from Latin America. So this disease is a neglected tropical disease. It's much more common in like Central and South America, in areas where the housing tends to have like more nooks and crannies and be less insulated. And so it's easier for the bugs to get inside of the house, or inside of like factories that make juice and stuff like that, where the bugs can get sort of ground up with the rest of the juice. So most of the people who have it in the United States are immigrants. And so what I worry about is that our doctors aren't good at recognizing this because it wasn't a problem in the United States. And we're sort of only recognizing that it's a problem

• 14:51Kelly Weinersmith?

  because people have moved to the United States with it. And so I think often a lot of people don't get diagnosed when they could get diagnosed. And there's blood tests now. And so I feel like one good thing about the fact that this parasite has made it into the news, and I'm hearing from like friends and family members who haven't written in decades because they remembered Kelly studied parasites, and they want to know if they should worry about kissing bugs. And I'm happy to answer those questions. But I think one of the good things is this is getting on people's radars. Now, and so I'm hoping that people thinking, oh, gosh, this could infect me. Well, maybe allow us to raise some money so that we can raise awareness about this. Make sure it's on every doctor's radar. Maybe we could get some better treatments, some better medications. But me, living in a house that's well sealed and as someone who would be able to identify

• 15:35Kelly Weinersmith?

  a kissing bug in the house, if it got in the house, I'm not personally worried. I'm a little worried about like dogs that sleep outside at night and I have a livestock guardian dog. I mean, this can infect any mammal. So like opossums and raccoons tend to have it. I'm sure, you know, this could be much more of a problem for people who are unhoused. But as a housed person in a well insulated, secure house, I am not personally worried.

• 15:57Daniel Whiteson?

  All right. Well, thank you for the deep download of information, as disturbing as some of it was.

• 16:01Kelly Weinersmith?

  Sorry, just real quick, I want to say, uh, I am not a medical doctor. And, and so if you are concerned that you have Chagas disease, you should talk to a doctor and, you know, just because I'm worried, doesn't mean there's absolutely zero risk that it could be in your house. And this is where I reveal that I have anxiety. And so I still worry sometimes a little bit, but, but I think most of your worries should be about the population of people who might have picked up Chagas disease from their home countries and brought it here. So we should be trying to help those people.

• 16:27Daniel Whiteson?

  All right. So let's check in with Zach and see if this made him more or less worried.

• 16:33Speaker 06

  Hello again, extraordinaries. Thank you so much for answering my question about kissing bugs. You definitely gave a more thorough explanation than I was even hoping for as usual. It sounds like as a Minnesotan, I don't personally have to worry about this unless I'm traveling somewhere warmer, but I appreciate the opportunity to spread some public health knowledge and maybe get some more visibility for a disease that could really impact people who aren't me. Thanks again.

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• 20:09Daniel Whiteson?

  All right, we're back. And we're going to do a major pivot from earthly questions about the butt-to-mouth pipeline to lines of plasma in the sun.

• 20:19Kelly Weinersmith?

  It's hard for me to see how we're going to get to cannibalism with this question, but hopefully we make it.

• 20:24Daniel Whiteson?

  Well, if the sun absorbs the earth, is that sort of like solar system cannibalism?

• 20:29Kelly Weinersmith?

  It's a stretch, Daniel. It's a stretch. I might give it to you, but I think that's not what most people are thinking of.

• 20:35Daniel Whiteson?

  All right. Well, here's a really insightful question about a very subtle point of magnetism from Michael Woodham.

• 20:41Speaker 12

  When I was a physics student, I learned about magnetic fields via Maxwell's equations. Magnetic field lines never join, never intersect, and never terminate. So it's impossible for one field line to pass through another. But when I studied astronomy, I learned that in the corona of the sun, magnetic fields get so twisted that they break and reconnect, resulting in a solar flare. What's missing from Maxwell's equation description that lets this happen? Can we observe this reconnection happening in a laboratory?

• 21:11Kelly Weinersmith?

  Oh, okay. There's a lot of different ways we could enter this question. Now, let's start with what is a field?

• 21:16Daniel Whiteson?

  Yeah, so Maxwell's equations are the ones that tell us how electricity and magnetism work, and specifically how they slosh back and forth between each other. How electric currents can cause magnetic fields, how changing magnetic fields can cause electric currents, all sorts of stuff. It's a brilliant piece of work from 150 years ago, which was then updated and quantummechanized by Feynman and other folks to our modern understanding of electricity and magnetism.

• 21:41Kelly Weinersmith?

  Yeah, and for more history of Maxwell's equations, folks should listen to our episode with Kathy Does Physics because she gave so much great insight into this story. But anyway, sorry, I remember Maxwell got a lot of equations wrong, and that made me feel great, and someone else had to fix it. So, sorry, go ahead.

• 21:56Daniel Whiteson?

  Yeah, his notation was really confusing, and he made a lot of mistakes. And it was Heaviside who came in and cleaned it up. He spent like a decade alone in like an attic working on these equations. And the equations we now know and love are mostly actually due to Heaviside's formulation. A lot of important work done by a lot of people. But the central concept of Maxwell's equations are these fields, the electric field and the magnetic field, and how they relate. So let's start, since we're going to be talking about field lines, let's remind ourselves, what is a field anyway?

• 22:26Kelly Weinersmith?

  So when I picture a field, I like literally picture a soccer field that maybe undulates sometimes. So Craig, you're laughing, so that must be pretty wrong.

• 22:38Daniel Whiteson?

  No, it's actually pretty accurate.

• 22:39Kelly Weinersmith?

  Okay.

• 22:40Daniel Whiteson?

  Yeah, a field in physics is just assigning numbers to space, to saying, let's put the number seven here, and let's put the number nine there. And if you have numbers everywhere in space, that's a field. Electricity and magnetism are more complicated fields because at every point in space, they don't have a number, they have a vector. They have three numbers, so like a little arrow with a direction and a length. So the electric field is like a little arrow at every point in space, and the same for the magnetic field.

• 23:08Kelly Weinersmith?

  Okay, got it. I can picture that.

• 23:09Daniel Whiteson?

  All right. Now, this field, it's a really important concept and physicists talk about it as if it was real, like the field is out there, but we don't really know that philosophically. It's just sort of like a construct we use to explain phenomena we observe and it's very useful intermediate. We don't really know if the field is physical, like is the field there when you're not measuring it? You can't see it directly. All you can do is like drop a particle into it and see its effects. So remember that a field is sort of like a construct.

• 23:39Kelly Weinersmith?

  All right. So are we getting philosophical or does this impact like predictions as well?

• 23:43Daniel Whiteson?

  I just can't talk about fields without mentioning that this is something we don't know if it actually exists or not.

• 23:49Kelly Weinersmith?

  And I'm here for the philosophy too.

• 23:50Daniel Whiteson?

  And that's important because the next thing we're going to talk about is extra philosophical, which is a field line. So often we try to describe fields, we try to like draw fields on paper. And one thing you could do is like draw a bunch of arrows at every point in space. And that technically is a good description of the field, but it's kind of hard to look at. And so instead, people develop this concept of a field line. And the field line is a line that points along the direction of the field. So mathematically speaking, it's tangent to the magnetic field vector. More practically, if you're looking at a bar magnet, you can draw like field lines from the north to the south. That shows you the direction of the magnetic field along that line. And you can draw more lines and you put them closer together

• 24:33Daniel Whiteson?

  where the magnetic field is changing a lot and further apart when it's not changing. So in that sense, there's sort of like lines on a contour map that show you where the height is equal. Here it shows you where the magnetic field is constant and the direction along which a compass would point if you put it there.

• 24:48Kelly Weinersmith?

  Okay, so I'm imagining my undulating soccer field that is made up of three points and I've got arrows and they've got different heights. Is there like a line above each arrow or like above each set of arrows? I guess it could be whatever you decided you want. Is that like a reasonable way to imagine it?

• 25:07Daniel Whiteson?

  It's like if you find a bunch of arrows that are all pointing along the same direction, you would draw a line along them.

• 25:14Kelly Weinersmith?

  Okay.

• 25:15Daniel Whiteson?

  So back to our example of contour lines, imagine if you have a hill and you draw contour lines around it like a circles. What happens when that hill gets flattened? Where do the contour lines go? How do you draw contour lines on a flat plane? You could draw them in lots of different ways. They're sort of arbitrary. So imagine now you're you have a hill that becomes flat and then it becomes a divot. So the contour lines in that sense sort of are discontinuous because there's that moment when it's not they're not really well defined in the middle. And that's what's happening with the plasma flux tubes and the magnetic field. They're clear field lines in one direction, but then there's this moment when the flux tubes are crossing and the things cancel out and you don't really know how to draw the field lines. And then a moment later, you know how to draw them again. And

• 25:57Daniel Whiteson?

  so there's a discontinuity from before to after.

• 26:01Kelly Weinersmith?

  Got it. Okay.

• 26:02Daniel Whiteson?

  But these are lines that we have drawn in our minds. Magnetic field lines, not physical things. You can't like go out and touch one and push one, right? Somebody else could draw lines differently than you do. So they're helpful for understanding the flow of the magnetic field, but they're not physical things themselves.

• 26:18Kelly Weinersmith?

  Got it. Okay. They're a human construct to describe behavior.

• 26:22Daniel Whiteson?

  Exactly. Like in the same way that if you're hiking and you're using a contour map, you shouldn't look for those lines in the ground to know where you are, right? That's foolish.

• 26:30Kelly Weinersmith?

  That would be confusing. Yeah.

• 26:32Daniel Whiteson?

  They're actually maybe kind of helpful for hiking, right?

• 26:35Kelly Weinersmith?

  Yeah, sure. I wouldn't want to be the one who had to like draw the contour lines. But yeah.

• 26:38Daniel Whiteson?

  Exactly. All right. So Michael makes this point that contour lines don't terminate. They don't break, right? And this is the property of magnetic fields only, not electric fields, because we don't have magnetic monopoles in our universe. A north pole or a south pole is where a magnetic field would begin. So if you had just like a north pole out in space by itself, the magnetic field lines would all point away from it. The same way if you put an electron in space, the electric field all points away from it or towards it, depending on the charge of the particle. And so in our universe, we have no single north poles or single south poles. They all come together. They're dipoles. We have no magnetic monopoles in our universe. So we've talked about that on a previous episode, so I'll just leave that there.

• 27:21Daniel Whiteson?

  But what that means is that magnetic field lines don't start or end, they're always in a loop. So if you have like a bar magnet, there is a magnetic field that starts from the north pole and then goes down to the south pole. But then it goes through the bar magnet between the south and the north pole. So it always forms this continuous loop. In order to have a magnetic field line that ends somewhere, you'd need an isolated north pole or an isolated south pole. You'd need a monopole.

• 27:47Kelly Weinersmith?

  Okay, and Maxwell proved that with his equations, is that right?

• 27:51Daniel Whiteson?

  A great question. Maxwell's equations show you that you can't have a break or an end to a magnetic field if you have no monopoles. But if you did find a monopole, then that would do that, right? But we've never seen a monopole. As far as we know, there are no monopoles in the universe. So all magnetic field lines are loops for that reason.

• 28:09Kelly Weinersmith?

  Got it, okay, but not on the sun?

• 28:13Daniel Whiteson?

  So now we're set up to talk about the sun, which is like maybe the most complicated electromagnetic object in the neighborhood, right? Because it's plasma. Plasma is an ionized gas. So you take something like hydrogen, which has a proton and an electron, and you heat it up so that the electrons are no longer bound by the protons, they're flying around free. So you have a gas, which is already very complicated to model because it's high density, high pressure, it's chaotic. And now you add the fact that there are electric charges on all those particles. So not only do you have to deal with complicated fluid dynamics, plus you have electric and magnetic fields in there. So this is a whole area of study. It's called magnetohydrodynamics, and it's famously a headache.

• 28:57Kelly Weinersmith?

  I mean, but it sounds pretty cool.

• 29:00Daniel Whiteson?

  It has a cool name, yeah, that's true. So the equations of magnetohydrodynamics are the equations of fluid dynamics, which are famously complicated, plus the equations of electromagnetism. And so you get all these really complicated effects. And in the sun, you get these tubes of plasma that are flowing like currents. And because it's electrically charged, there is an electric current, and so you get magnetic fields generated in lines around them. And there's really complicated behavior because the sun is chaotic and turbulent. So these tubes of plasma, sometimes they're flowing nicely alongside each other like lanes on a highway. But sometimes somebody crosses the lane and everything gets tangled up and the tubes do all sorts of crazy stuff and they snap and they rearrange.

• 29:43Daniel Whiteson?

  And when that happens, you get crazy effects from the magnetic fields also.

• 29:47Kelly Weinersmith?

  And just to be clear, so I think you told me in a previous episode that we really have never seen a monopole. And so it's not that the sun is creating monopoles, something else. It's just all this craziness when they're intersecting and fluids.

• 30:00Daniel Whiteson?

  Exactly. The sun is not creating monopoles as far as we know. But many popular science treatments describe this behavior where complicated tubes of plasma are crossing and snapping, doing all sorts of stuff, as magnetic field lines tangling and breaking.

• 30:16Kelly Weinersmith?

  Hmm, okay.

• 30:17Daniel Whiteson?

  And this is what Michael is asking about. He's like, doesn't that violate Maxwell's equations? And the answer is no, it doesn't violate Maxwell's equations, though the description is a little bit confusing and we're going to take it apart and make it clear.

• 30:28Kelly Weinersmith?

  All right, take it apart, Daniel.

• 30:31Daniel Whiteson?

  So what's happening is that you get plasma currents and sometimes they're going in opposite directions, sometimes they're the same directions, but they come near each other. And sometimes when they come close to each other, the magnetic field between them can cancel. Remember that magnetic fields are a vector and they're linear. So if you have like a magnetic field generated by one object that's in one direction and a magnetic field in the exact opposite direction generated by something else, they can cancel each other out. So you can have an area between two like tubes of plasma with no magnetic field in it. The two things can cancel, even if you're in an area of very strong magnetic activity. Right? This is just like destructive interference between waves, right? You can have a point in a wave where there's no amplitude.

• 31:15Daniel Whiteson?

  And so that's what's happening, that there are locations between these plasma flux tubes that have no magnetic field because of this cancellation. And at that point, the direction of the field lines are not well-defined. You could draw them in lots of different directions because the field is zero there and the derivative can be zero as well. And so if you're going to sit down and draw them- The field lines, you have some arbitrary choices to make. And the moment before that happens and the moment after that happens, the field lines you would draw are very different. So yes, the field lines from one moment to another have like a discontinuity where you're like, before this thing happens, I would draw the field lines here. Just after it happens, I would draw the field lines there.

• 31:56Daniel Whiteson?

  And there's not a smooth transition where you can say at every moment, the field lines move. But remember, field lines are arbitrary. They're what we make up in our minds, just our description. It's like back to our contour example, if you had an earthquake and you had to draw contour lines over a peak somewhere, you're like, well, I could draw a contour line in many different directions. As this peak is shifting and going up and down. And so there's a moment there where you don't know exactly how to draw the field lines. So what's really happening is the physics, the physical things that's happening is that these flux tubes are breaking and snapping and doing all sorts of crazy stuff. And that's creating the solar flare where the sun is going to spit out a huge arc of plasma, which maybe is going to eat the earth in an act of astronomical cannibalism.

• 32:38Kelly Weinersmith?

  Oh, nice.

• 32:42Daniel Whiteson?

  And the field lines are confusing, but the field lines are not breaking. There's no divergence there. There's no source of the field lines. It's just that the field lines, you draw them one way and then you would draw them another way a moment later. So they are not actually breaking. There are no monopoles in the sun.

• 32:58Kelly Weinersmith?

  Okay, so I'm trying to decide, does the fact that we're not calling this a break, like make this concept less useful because it's clearly a human construct? Or does this just teach us something particularly important about the sun in this framework that we've created?

• 33:16Daniel Whiteson?

  I think it also teaches us something with the limitations of language. You know, the field lines transition from here to there, but they never have any divergence. They are continuous. There's never an end point. Even though there's a discontinuity from moment to moment about how you would draw them. So yes, the sun is chaotic and we have a lot to learn about how plasma works and how to keep it stable. And we've done a bunch of experiments to see these kinds of effects here on earth. That's the second part of Michael's question. Yes, we see this kind of stuff happening all the time in magnetic confinement fusion. When we built Tokamak, we tried to recreate the conditions of the sun so that we can have fusion here on earth. And this is something people work on and struggle with. They try to minimize the chaos and keep those flux tubes steady.

• 33:59Daniel Whiteson?

  And so there's lots of observations of these kinds of effects in the lab. Usually it's what you don't want to happen. But we see it anyway. So plasma turbulence is definitely something we've seen in the lab. We can recreate. We struggle to model it because turbulence is very difficult. It requires serious computation because it's chaotic. So it's very, very sensitive to the initial conditions. But it's not new physics in the sense that it's like a magnetic monopole or violating Maxwell's equations.

• 34:26Kelly Weinersmith?

  Can we still apply Maxwell's equations in these conditions?

• 34:30Daniel Whiteson?

  Or? Oh, yeah.

• 34:31Kelly Weinersmith?

  Yeah. Okay.

• 34:32Daniel Whiteson?

  Absolutely. The only time you can't apply Maxwell's equations is when you have quantum effects, like the level of photons and individual particles doing quantum stuff. But the sun is big and basically classical. And so you can definitely use Maxwell's equations to describe it.

• 34:46Kelly Weinersmith?

  Great.

• 34:46Daniel Whiteson?

  And then when there are quantum effects, you use quantum electrodynamics, which is just a quantum version of Maxwell's equations anyway. So yeah, Maxwell was right as far as we know.

• 34:55Kelly Weinersmith?

  Okay. And so that wouldn't be quantum magnetohydrodynamics, which sounds even cooler, right? That's, that's, that would be a different field?

• 35:05Daniel Whiteson?

  I'm not aware of that, but that's a cool title for a grant proposal.

• 35:08Kelly Weinersmith?

  There you go. All right. Let's see if Michael feels like he understands Maxwell's equations a little better now.

• 35:14Speaker 12

  Thank you. That was an informative answer. I enjoyed the description of magnetic field lines. Ever since sending in this question, I've been wondering how you'd handle that. I am mildly surprised that the magnetic field lines manage their realignment trick without resorting to quantum mechanics.

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• 38:11Daniel Whiteson?

  All right, we're back. We started on Earth, understanding kissing bugs and poop. Then we went out into space to understand what's happening in the sun. And now we're gonna bring that all together to talk about poop in space.

• 38:26Kelly Weinersmith?

  Yeah, you know, I love, I study parasites and space. We've got both of them in one episode and poop is what connects them.

• 38:32Daniel Whiteson?

  Amazing.

• 38:32Kelly Weinersmith?

  And that is a good summary of my life. So.

• 38:35Daniel Whiteson?

  We should have invited our vice president for poop research on this podcast. Yeah.

• 38:40Kelly Weinersmith?

  Why is she not president of poop research? You're clearly not president of poop research.

• 38:45Daniel Whiteson?

  Well, we've got a lot of vice presidents, you know, and so the vice president for this, vice president for that.

• 38:49Kelly Weinersmith?

  Got it. All right. Well.

• 38:51Daniel Whiteson?

  But you're right. She should be president. Yeah, I'll propose that to the next board meeting.

• 38:55Kelly Weinersmith?

  Okay. Yeah, that sounds good. It doesn't seem like anyone else in your family is qualified. I'll just say, but all right.

• 39:00Daniel Whiteson?

  And I think that we should send our answer here, not just to John, but also to Katrina for response.

• 39:06Kelly Weinersmith?

  Oh, I'm nervous.

• 39:08Daniel Whiteson?

  You all should have seen Kelly's face.

• 39:10Kelly Weinersmith?

  The president of poop research at the Weitzin Institute. I mean, this is a big deal. Okay.

• 39:14Daniel Whiteson?

  Yes. Your adjunct status at the Weitzin Institute might be on the line here.

• 39:18Kelly Weinersmith?

  Oh, no. I guess the good news is I don't get a lot of perks from that adjunct status.

• 39:24Daniel Whiteson?

  What? What? The prestige alone. Oh, my gosh.

• 39:28Kelly Weinersmith?

  That's right. That's, I guess I get friendship, which is the most valuable thing on this planet.

• 39:32Daniel Whiteson?

  All right, let's stop beating on the bush and let's hear John's question about poop in space.

• 39:37Speaker 14

  Hello, Daniel and Kelly. I had three questions in regards to the microbiome in space. First, do the microbiomes of all the people on the ISS at a given time become the same? Second, how do things change with every supply delivery or crew change? And third, how does zero G affect the microbiome? Thanks.

• 39:56Kelly Weinersmith?

  Oh, my gosh. Loads of amazing questions here. So I split these questions up. So first, let's talk about, do the astronaut microbiomes become the same on the International Space Station? And let's start by saying they don't become the same, but they do become more similar. So, you know, the same would imply the exact same species and the exact same abundances. That's not what happens.

• 40:18Daniel Whiteson?

  All right. Well, let's start by reminding people what a microbiome is and why it might become the same anyway.

• 40:24Kelly Weinersmith?

  Oh, okay. Well, I just assume that all of our listeners have listened to all of Katrina's amazing episodes. I'm gonna butter Katrina up here at the beginning of the answer.

• 40:32Daniel Whiteson?

  All right, nice.

• 40:33Kelly Weinersmith?

  So, all right, so the, you know, your microbiome is the collection of viruses, bacteria, fungi that live all over your body, including in your gut, on your face, in your saliva, you know, in your mouth, on your teeth. They're everywhere. And they can be important for a lot of different reasons. They can, you know, support inflammation, which is bad for you. They can help you digest food, which is good for you. They can help you battle pathogens, which is obviously good for you. And so it's a dynamic community that changes over time for a variety of reasons. And one of the ways that it changes on Earth is if you move in with somebody new and you spend a lot of time with them. You, over time, have microbiomes that are more similar, not necessarily exactly the same, because

• 41:17Kelly Weinersmith?

  maybe you all are eating different foods when you're at work or something like that. But you have more similar microbiomes when you live with someone over time.

• 41:25Daniel Whiteson?

  So you love someone, you live with them, you end up eating their poop?

• 41:29Kelly Weinersmith?

  Yeah.

• 41:30Daniel Whiteson?

  Another example of the butt-to-face pipeline.

• 41:33Kelly Weinersmith?

  That's right. I mean, even if you don't love them, but you live with them, you're probably eating their poop.

• 41:40Daniel Whiteson?

  I feel like it's easier to digest that fact if you do love them, but.

• 41:44Kelly Weinersmith?

  Yeah. All right.

• 41:46Daniel Whiteson?

  All right. So then the fascinating question is, we know that happens for roommates here on Earth. And the question is, what about roommates in space? How does this happen? And is affected by supplies or crew changes or zero G?

• 41:57Kelly Weinersmith?

  Yeah. All right. So there was, I was able to find a study where they looked at astronauts, nine of them, that were in space for somewhere between six to 12 months on the International Space Station. And they looked at their microbiomes on different parts of their bodies. And then they compared the microbiomes on different parts of their bodies to each other, to each of the different astronauts. And they did find that when people went into space, first of all, some aspects of their microbiomes got more diverse. So they went into space and they picked up a few new bacterial species. And that could have been from the astronauts that just arrived, or from astronauts that were on there from the crew before and left some of their microbes behind.

• 42:34Daniel Whiteson?

  Or alien invasive microbes?

• 42:36Kelly Weinersmith?

  Probably yes, Daniel. Probably yes. Or no.

• 42:43Daniel Whiteson?

  That voice tells you Kelly is humoring me.

• 42:48Kelly Weinersmith?

  Well, we at the White's and Institute have to have a lot of patience.

• 42:53Daniel Whiteson?

  Wow, you're angling for that patience award, huh?

• 42:56Kelly Weinersmith?

  No, Katrina's got it.

• 42:57Daniel Whiteson?

  She's won it 20 years running, let me tell you.

• 43:00Kelly Weinersmith?

  That's right. Yes, it's definitely Katrina's.

• 43:02Daniel Whiteson?

  Okay. All right. So they're out there, they're living together. Obviously, they're sharing the same air, they're using the same bathroom. So all this stuff's going to get intermingled. It makes sense for their microbiomes to become intermingled.

• 43:15Kelly Weinersmith?

  And that is indeed what they found. They found that if you look at their gut microbes over time, they became more similar. So they had similar species over time. So like some people picked up some bacterial species, some maybe lost some bacterial species. And so over time, they do start having similar community members that they're swapping. And they think that a big part of why this is happening is because they're all eating pretty much the same limited food options. So, you know, the International Space Station does have 200 different items that you can order. But it's all, you know, it's all pretty similar and has a lot of the same ingredients. And so their gut microbiome is being fed pretty similar stuff.

• 43:57Kelly Weinersmith?

  And part of what you eat supports different members of your gut community. And so they argued that they thought food was driving a lot of this similarity. But also they're sharing an environment in pretty intimate, small quarters. I think the International Space Station, you know, if you put two one-bedroom apartments together, the International Space Station probably doesn't have much more room than that. And there's like, you know, six to 10 roommates in there. So it's pretty cramped, lots of microbes. You can't shower. You can like wipe yourself down, but you're not like, you know, really getting a nice shower like you would here at home. But they noted that even astronauts that tended to be working in different parts of the International Space Station and didn't spend a lot of time together, still ended up with similar microbes, which is why they thought maybe it had something to do with the food.

• 44:41Daniel Whiteson?

  Even if you're just breathing the same air, isn't that enough? Even if you're not like often touching the same surfaces, it feels like that should be plenty.

• 44:48Kelly Weinersmith?

  Yeah, I agree. They felt like food was pretty important, but I don't see why it wouldn't be, hey, we're touching the same surfaces and then we touch our food and that's the kind of, you know, that determines what bacteria are going into our body. And at the end of the day, it's, it's almost certainly not just one thing. It's probably a lot of different things.

• 45:03Daniel Whiteson?

  And how they replicated this kind of environment here on Earth in order to test and to understand how long it takes and under what conditions?

• 45:09Kelly Weinersmith?

  Yes. So, uh, so there have been two like year-long analog experiments that they've done here on Earth. There was Mars 500, which was done in Russia, and they looked at how the microbe changed when you have quote unquote astronauts pretending to go on a mission to Mars.

• 45:26Daniel Whiteson?

  Quote unquote astronauts. Wow. Wow. Fire there, Kelly.

• 45:32Kelly Weinersmith?

  I don't think that there'd be too much debate amongst the community of professional astronauts that they are simulation astronauts instead of astronaut astronauts.

• 45:41Daniel Whiteson?

  But I bet when they introduce themselves, they don't say, I'm an astronaut and then they use air quotes.

• 45:48Kelly Weinersmith?

  They might call themselves an analog astronaut or something like, I don't remember exactly what the term is, but you know, I think the FAA has a rule where you have to have, you know, gone past the Von Karman line to be called an astronaut. And so, you know, I think technically I'm not being a jerk.

• 46:03Daniel Whiteson?

  No, but I think using scare quotes puts them in the category of like kids who have dressed up as a quote unquote astronaut for Halloween, not really an astronaut.

• 46:13Kelly Weinersmith?

  I see, but only you were seeing the scare quotes. You outed me, but.

• 46:17Daniel Whiteson?

  You said quote unquote astronaut. Anyway.

• 46:20Kelly Weinersmith?

  Oh, shoot.

• 46:20Daniel Whiteson?

  So these quote unquote astronauts, should we take them seriously, have done this really incredible thing of living isolated for six months or up to a year. So what did we learn from these studies?

• 46:31Kelly Weinersmith?

  They found that the dominant species in the microbiome tended to stay the same. So like the species that they had the most of when they went in there persisted, but the more rare strains of bacteria that they had when they went into the facility, those tended to become the same. So like your dominant bacterial species, that was pretty similar, but some of the like rare ones started to homogenize between the crew members. And for two of them, they changed back to their original state pretty soon after this analog mission was done. And I won't use quotes around missions so that you don't imply that I'm laughing at people and.

• 47:12Kelly Weinersmith?

  All right. And then the other four had a Mars 500-esque microbiome for up to six months. So those changes persisted for them. And the surfaces inside of Mars 500 started to look sort of like the microbiome on the exterior, you know, like the skin parts of the crew, which is something we also see on the International Space Station. And then there was also a study on the Hawaiian Space Exploration Analog and Simulation 4 mission. So that's Hi-Cs 4. And they found, and this is gross, that, like, here, let me find the quote, "Microbial diversity of skin samples from the Hi-Cs 4 crew successively increased and showed a delayed longitudinal

• 47:54Kelly Weinersmith?

  homogenization with microbial diversity estimates from surfaces, mainly due to complications with the composting toilet."

• 48:02Daniel Whiteson?

  Oh, no.

• 48:05Kelly Weinersmith?

  The point here is that there was a lot of poop getting on their skin. And so they were seeing evidence of that on their skin microbiome.

• 48:16Daniel Whiteson?

  Wow.

• 48:16Kelly Weinersmith?

  And that was impacting the results. And space is gross. So this is actually-

• 48:20Daniel Whiteson?

  The poop to skin pipeline.

• 48:21Kelly Weinersmith?

  The poop to skin pipeline. So anyway, composting toilet was getting things pretty gross up in there.

• 48:27Daniel Whiteson?

  Do you think in the Hi-Cs, they were waking up with poop on their face, the way people in Virginia do when they're bitten by a kissing bug?

• 48:33Kelly Weinersmith?

  You know, I would bet that LA has a lot more cases of kissing bug than all of Virginia. So-

• 48:39Daniel Whiteson?

  All right, we're gonna look that up and see. We're gonna look that up.

• 48:42Kelly Weinersmith?

  Okay, sounds good.

• 48:42Daniel Whiteson?

  All right. So the other part of his question was whether this was affected by deliveries or crew changes.

• 48:48Kelly Weinersmith?

  So I don't think it's very affected by delivery. So they're pretty careful to sterilize things before they put them in the like modules to send them up to space. They're super careful about that, like sterilizing the food and whatnot. And so there's probably not a ton of microbes in there. I mean, it would be amazing to me if there were no microbes in there, because like, you can never get rid of all the microbes. But I don't think that's a big contributor. And neither did the papers that I read. They didn't imply that was a big contributor either. But there was a study that looked at different surfaces on the International Space Station, and they looked at how the- Microbes on those surfaces changed over time as crew members changed over 33 months. So crew members tend to change every like three or six months or something like that.

• 49:31Kelly Weinersmith?

  And they did see that the bacteria on the surfaces of the International Space Station were changing over time in ways that seemed to reflect changes in the crew. So you'd get a change in the crew and you'd look at their skin microbiome. And a few months later, the surfaces of the International Space Station would look more like the microbiome of the crew. And then a new crew would come and that cycle would sort of start again. They had similarity in species, but not necessarily similarity in the abundance. So for example, maybe the humans and the surfaces both had bacteria species A, B, C, and D, hypothetical example.

• 50:12Kelly Weinersmith?

  But for humans, maybe A, B, C, and D were at abundances of like, you know, 80%, 10%, 5%, and 5% respectively. But on the surfaces, maybe it was something more like 25% for each species. So different abundances, but similar species. So that at least suggests that when a new crew comes, they're spreading their microbe through the habitat and likely to spread that to whoever else is residing on the station.

• 50:38Daniel Whiteson?

  And something I've learned from our president for microbial research is that the abundance of the bacteria depend essentially on the conditions. Like, are you feeding it the right thing? Is it at the right temperature? And so I wonder if the conditions on the space station are different from the conditions on the ground in some important way that you would get like the growth of a different bacteria. And the listener asked this great question about zero G. Does gravity affect the growth of microbes?

• 51:03Kelly Weinersmith?

  Yeah, so the listener also pointed out that it's probably a really hard thing to study. And so I'd like to highlight first that, yeah, it's a really hard thing to study. So I mean, if you're looking at the microbiome of astronauts, you know, microgravity is changing, but they're also exposed to a little bit more space radiation. They're probably more stressed out than they are on Earth because they have a very packed schedule of experiments and stuff that are super expensive and they don't sleep very well. There's data on that. So a lot of stuff is changing when they're up there and it's hard to sort of isolate things.

• 51:35Daniel Whiteson?

  Yeah.

• 51:35Kelly Weinersmith?

  We have done some studies that suggest that microgravity impacts bacteria in a variety of different ways. So this isn't talking about microbiomes. This is just looking at bacteria. And they form biofilms differently. So biofilms are when bacteria sort of like adhere themselves together. And that makes them a little bit more resistant to the immune system and antibiotics and stuff like that. They also produce different amounts of virulence factors. They're they have different levels of resistance to antimicrobials. So we do have some evidence that microgravity impacts bacteria in some ways, but it's not clear what the impact is on the microbiome. So when you're aggregating all of the bacteria.

• 52:18Kelly Weinersmith?

  And I was able to find one study that was starting to try to separate these different pieces. And so what they did was it was a study with rodents where they put the rodents in a harness, where they were trying to simulate lunar gravity by lifting them up so that only like one sixth of their mass was like touching the ground. So it's like they weighed one sixth as much. And then they also were doing some radiation experiments and they did find that like some community members in the microbiome shifted a bit. But it's kind of hard for me to know if like feeling like you weigh less is going to be the same as really being in a microgravity environment and you're in this harness. And that's probably stressful because you know, the rodents are like, what the, why am I confined?

• 53:01Kelly Weinersmith?

  I can't move around. It's it's hard to nail this stuff down. And I wasn't able to find studies that tried to nail it down in humans. There's reason to suggest that the low gravity environment probably is impacting bacteria in a way that scales up to the level of the microbiome. But I think at the moment, we don't really understand that.

• 53:19Daniel Whiteson?

  All right. Awesome. Well, that's a fascinating look at microbiomes in space and the life of astronauts. Let's send this answer over to our president for microbial research and hear what she has to say.

• 53:32Kelly Weinersmith?

  And let's hear what John has to say.

• 53:34Daniel Whiteson?

  Absolutely.

• 53:35Kelly Weinersmith?

  Oh, I'm worried about what Katrina has to say. I hope I got it right.

• 53:40Daniel Whiteson?

  So Katrina, what did you think?

• 53:42Speaker 15

  Well, I have to say, I was playing in my mind the studies that Kelly brought up, like, seconds before she said them, so that was very satisfying. So, nice job with your research, Kelly. In some cases-

• 53:53Daniel Whiteson?

  That's some real approval, right there, from the president.

• 53:56Speaker 15

  In some cases, those are like talks I have seen, like, I've met the scientists who led the studies. So, for example, the microgravity studies with the bacteria showing the changes in biofilm formation and virulence factor expression. I met the scientist, a scientist who led a study like that. It was published in Nature Gravity. And, uh, and she had these crazy contraptions, where they would, kinda like at the, at an amusement park, where they like spin you in circles and then there's less gravity. They did that to the microbes. So she was conducting those experiments on Earth, but changing the gravity that the microbes felt. And so that was a cool way that those experiments were done. And yeah, I think there are changes that we've only studied at the smaller scale, and

• 54:39Speaker 15

  we don't know how they synchronize up at the bigger scale, which I know is a real theme for you guys. So, you know, does one microbe by itself, when put together with 10 to the 29 microbes, is there like a new simplicity that emerges? I don't know. And then just on the space analog front, I'm, I also, I was really interested in that for a long time. In fact, I wrote proposals to the Australian Antarctic Division many times, with the hope of studying the Australian Antarctic researchers, who live on some of the most isolated bases down in Antarctica. Sometimes only like 10 people will spend the whole winter, eight months together, with no new shipments coming in. And so it's

• 55:20Speaker 15

  a way of learning about people in close quarters, and experiencing stress that's similar to what astronauts experience, minus the whole gravity thing. And I think they have a little more access to fresh air, for example. But, uh, anyway, I never did get the proposal to do that. But I think it's really interesting. They have definitely seen changes in how your immune system is functioning. And just keep in mind that your microbes and your immune cells are a big- There's a lot going on with the interactions between the immune cells and the microbes. So as stress and environment change and your immune system changes, that's a big pressure that will influence which microbes can thrive in your body.

• 56:03Speaker 15

  So I'm very sure that's a big part of how the microbiomes change. And all around, I think, yeah, it's just about exposure to the microbes from other people around you. And the conditions, like the food, will also have an impact. But it's like you need the microbes and the nutrients together to shape the community. So I'm sure both of those forces are really important. I actually also recently saw a NASA scientist give a talk about contamination from even astronauts wearing their space suits, going out on like spacewalks and on the surfaces of the International Space Station, for example. And if you take swabs out there,

• 56:47Speaker 15

  you find that there are microbes being dribbled, which is like, there's a real goal of the whole space community to avoid contaminating the universe with our Earth's microbes. And that's a really big challenge. So even the space suits, which are pretty well-contained, do not entirely prevent microbes from dribbling out. So if we went up to Mars, I mean, this is obviously, I have no idea when we might be doing this, but if we were to send people in space suits up to Mars to sample the rocks and try to learn about life, we would have a hard time not contaminating with our own microbes. And a lot of our methods are, you know, for low abundance, low biomass samples, they are right at the limit of detection.

• 57:29Speaker 15

  So it starts to become impossible to distinguish what's showing up in the kit reagents versus what's actually coming from the environment that you're sampling. So those are the things that the space microbiology community are thinking about, I think.

• 57:43Daniel Whiteson?

  So what grade would you give Kelly?

• 57:45Speaker 15

  Oh my gosh, I mean, 100%, maybe, actually, A+.

• 57:50Daniel Whiteson?

  All right. Good job, Kelly.

• 57:52Speaker 14

  Hello, Daniel and Kelly. Yes, you answered my questions. The most interesting point being that the major components of people's microbiomes remain stable under such close and isolated conditions. The immediate follow-ups that came to mind were whether the same effect was visible on the surfaces of the ISS. Thanks.

• 58:12Kelly Weinersmith?

  Hey, John. Great follow-up question. So the microbiome on the surface of the International Space Station, like, you know, the various computer screens and stuff like that, do tend to change over time in ways that reflect the makeup of the crew that's on the International Space Station. So there's a lag between new crew members coming on and all of the microbes that are covering their hands and their arms sort of getting on all of the surfaces. Thanks, John.

• 58:43Daniel Whiteson?

  All right. Thanks, everybody, for these wonderful questions. We thoroughly enjoy these discussions and gives us the opportunity to dig deep into a question we have sometimes wanted to understand better ourselves. So thank you very much for sharing your curiosity. Remember that science moves forward because of human curiosity, and that includes you.

• 59:02Kelly Weinersmith?

  So send us your questions at [email protected], or you can join us on our Discord channel. You can find an invitation to our Discord channel on our website, danielandkelly.org, or follow us on Instagram, Twitter, or Blue Sky at D and K Universe.

• 59:19Daniel Whiteson?

  Have a great day, everyone.

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