Welcome to Stuff you should know, a production of iHeartRadio. Hey, and welcome to the podcast. I'm Josh Clark with Charles W. Chuck Bryant, and guest producer Noel Noels in the house. It's the It and the New Studio. Yeah, man, this place is comfy, cozy. I like it. I wish um, you know, I wish there was a chair version of a water bed. I know this is a nappish little place. Yeah, especially today, I think I'm I'm dragging all apologies. Yeah, same here. So if we're talking kind of slow or low, or we just stopped talking for a little while, it's where its tired. Yeah. We bumped into you at the Hawks game last night. I know. Hey, how many does that you know? Yeah? Just the bumping. Yep, we were both at the Hawks. Gammy in the Hawks. One didn't even know we were going. No. Look over in the line. There's Josh and Yumi. Yeah that's great. There's Chuck and Eddie yep, each other in an arena of eighteen thousand bumping into someone. Is that it? That's all it holds. I think it's something like that. It's a good a lot of people. It's a good arena. Yeah, but you had box seats because you're special. They were free o. Mine were free to in. The nosebleeds Yeah, I like just about every seat in that place. Yeah, it's not too bad. I was. I was laughing about the nosebleeds going in, But then I got up there. I was like, this is great. Yeah you can see everything. Did your nose actually bleed just twice? Yeah, once out of a cheer excitement, and then once from the altitude and that was more of a spray, right yeah, yeah, just covering everyone. Everyone was like hawks, Boy, what a weird intro. It's a little weird, um, But I mean it kind of jibes a little bit because we're talking. Yeah, you're mentioning blood. Sure, I was shedding cells and blood. You were like blood is made up of sell and we shed tons of cells. But before we get to that, right, there's the fact of the podcast. You shed cells. Um. I want to mention this one thing I read. Yeah, it's called I think the title of the article is the Self is Moral. It's about like where we get our identity of self from, like where it's rooted. It was written by a person named Nina Stromeyer, I believe is on aon magazine. Just type in the self is moral aon It'll come up. I'll get you there. Uh and uh. It Towards the beginning, the author says, there's this very famous philosophical exercise, which you know, philosophers love to do, like mental exercises. Yeah, that's what that's all they have. So imagine you have like kind of imagine you have like a ship, right, like a boat, ye, a nice Yankee clipper okay, okay, And this Yankee clipper is slowly, over time kind of salvage for parts, okay, but rather than just being stripped, like every time a part is taken out, it's replaced and then over the course of like fifty one hundred years, as each plank, as each bolt, as each like masked head, even the thing the carved lady in front, yeah, eventually just gets replaced with something else. Yeah, a new carved lady that speaks of the time, right, you know? Is it still though, after every single part has been replaced, the same ship that it was before? Yeah, I see what you mean. I don't think that can be possible. Why not, especially if it has the same name and it's the same ship in the same place as before. It was just slowly, over time moved out. True, where does the self lie? Yeah, that's a good point, man, Like redoing a house, same thing, Yeah, I mean all the floors and the walls and the windows, Like when does it cease to become that same house that was built in nineteen thirty exactly? Isn't that cool? Yeah? It is really cool. And the reason that it applies to this episode is because over the course of your lifetime, a significant portion pretty much all of the cells in your body are going to like be replaced. Yeah, so that the the person even after you reach your adult self. Yeah, physically, by the time you die, assuming you're gonna die much later, you're you are essentially a different person, at least on the cellular level. Yeah. Thirty seven trillion cells ish, that's how many we have. Yeah, that's what they estimate. And I did a little looking into lifespans. Sounds like an estimate thirty seven trillions. Yeah, what do you want, like like give or take? Yeah, I did a little research into lifespans just because this all sort of comes back to, like your death basically, because that's all death is is your your cells, you know, dying little by little. Well, yeah, I mean if you think about it, chuck, one of the things that like why do we die? If our we'll get to all that, but it's intriguing, you know, it started, you know, questions started popping up. So apparently we gain about three months every three months of life humanity every year that we progress, Like the average lifespans spans by three months. Yeah, Like if you were born in twenty twelve, the average lifespan is now and this is the United States, is seventy eight point eight. If you were born in nineteen oh one, it was about forty seven and fifty years for men and women respectively. But if you look at the ratio, it's still about three months. Despite all our technologies, three months a year, every year, every year, just slowly creeping along. Yeah, Because I think the article it was like when we're going to live to be one hundred by average, and they say by the year twenty one hundred, if things hold, then the average human or American will be about one hundred years old. I thought that, so I guess that if things are steadily progressing, I had heard that like our generation would be either the last or the first, the last two to not hit triple digits or the first two on average. Yeah. Yeah, again these are all guesses, you know, so who knows. Plus if you believe in like, uh things, speeding science, speeding up? Yeah, what is that? Moore's law? Yea is at it? Yeah, applied to computer or though in that case right right, but I mean you can send it to other stuff. Yeah, then you might think, you know, it's it's but you know, they say it's not increasing like that. No, at least not so far. Moore's law is exponential growth just adding three months every years, non exponentials geometric. I think we're still at non exponential growth definitely. Yeah, we're just adding three months. Yeah, it's not bad though. That's pretty good average every four years. That's an extra year. Yeah. Well, and it's interesting to think about, you know, people that were born you know a lot of our colleagues like eight years behind us. We're going to live an average of two years longer. Yeah, that seems unfair, sad. Yeah, I know, what did they do? Just observe that we're thinking about our own deaths today. Yeah, and chuck that there's this rumor theory legend maybe okay, that your body regenerates itself, of your body regenerates itself every year. Yeah, that's not true. No, it's not true, but it was a very long standing rumor, and it was actually based on science. Yeah, you know, not just the idea that, oh, yeah, ourselves regenerate. So back of the envelope estimate is that, you know, we regenerate ninety five or ninety eight percent of ourselves every year. It was early experimentation by injecting radio act of isotopes into human beings and then following their course and then making estimates based on that led to this idea. It's called pulse labeling, is it. Yeah. It's like tagging an animal in the wild basically, right, but you're just tagging a cell, yeah, for specific types of cell. Yeah. They don't do that to humans anymore. No, it's very animals anything. It's a very dumb thing to do. Sure, ejecting radiation exactly, Yeah, unless, of course you know it's radiation treatment. That's true, which is still a really weird thing if you think about it. It's Yeah, I have a feeling it's gonna be like one of those things we look back on as like a primitive treatment. Yeah, yeah, yeah, I hope so. Um, but there there was this long standing science for decades or this idea, scientific idea that we regenerated ourselves by finally, and I think two thousand five, Um, there was a a researcher named doctor Jonas Freezing. He was Swedish. Dude's awesome. He said, this whole urban legend is really bringing me down. I want to figure out a way to really track how often the human body regenerates itself. Yeah, and the biggest question has been the brain, specifically the cerebral cortex and the heart and the heart muscles. I mean, they want to know all this stuff, but those were the two biggest mysteries. I think. Right, there's still the mysteries. But if you went back to prior to two thousand and five, in doctor Freeson's research, it was all a mystery. Yeah, he figured out he basically put a very accurate time stamp on how often human tissue and human cells regenerate themselves. Right, So the way he did this is very clever. For a long time, botanists knew that the trees around the world contained a spike of carbon fourteen radiation, Yes, thanks to humans and nuclear bombs. Exactly from nineteen fifty four to nineteen sixty three, tree rings for tree growth around the world show a big spike in carbon fourteen. Carbon fourteen is naturally occurring too, So like just cosmic rays from the Sun bombard Earth's atmosphere and create radioactive isotopes by knocking electrons from particles in our atmosphere, right, those radioactive particles become carbon fourteen, which is radioactive, and in the atmosphere, carbon fourteen binds to oxygen and creates carbon dioxide, which comes to Earth. Every living thing breathes this stuff in, whether it's a plant, whether it's a human, Like we just have C fourteen in our bodies. We also eat plants exactly contain the C fourteen bids breathing it in, and we also eat the animals that eat the plants that in just C fourteen. Right, Yeah, so like we got CAR fourteen in our bodies, that's right. But because of the spike in carbon fourteen that was introduced to the atmosphere from nuclear testing there there is a spike in humans as well. So you can roughly age like a human compared to another human if they were born in say nineteen fifty nine, and one who was born in nineteen seventy after there was that spike of carbon fourteen had gone away, right, right, that's pretty cool. But what doctor Freezen did is even cooler. He basically went back to those tree trunks, those tree rings that show a spike in carbon fourteen, and created a calendar of carbon fourteen to Kay and basically said, Okay, on this date, this is how much carbon fourteen was on Earth. And if I take this cell and compare it, knowing that carbon fourteen decays at a constant rate, yeah, I can tell you exactly how old this cell is exactly. And he used it to date cells and tissues and all sorts of cool stuff. Yeah. He he went looking for a marker and he found one due to our atomic testing program. Yeah, which is pretty weird. Just released all that junk in the atmosphere, and now all these years later it has a nice use. Yeah, you know it does. So we now know when we're gonna die, right, And the reason he was able to use this as a marker, Chuckers, is that, um, when you when you take a breath of life, your first breath of life. That's right, and you get some you get some of that C fourteen into your DNA um and a steady amount stays in there, like you don't keep ingesting C fourteen as far as I understand, as far as your DNA goes, Oh okay, once it's in your DNA, as your cells divide, yeah, that original amount becomes divided evenly. Right, So the less C fourteen that's in tissue, the older those that cell line, is right, or the younger the actual cells are, right? Is that right? I think so? Which would mean the new cell the marker would be a fresh batch of the C fourteen. No, it have less C fourteen? Oh really? Yeah, let's say you have because the cell divided, Yes, exactly, Yeah, like you have ten grams of C fourteen, which you don't. I can't imagine that would be Like let's say you're you're one cell that's never divided has ten Yeah, when it divides into two, it's each of those two cells is going to have five grants, and then two and a half and then one point seven five and so on and so on. Um, So, since you know that C fourteen is generated at a constell rate, you know that it decays that a half life of fifty seven hundred and thirty years. You can look at the amount of C fourteen and then also the decay of it as well. Yeah, you can date things that are no longer living too, to see when when they ingested that C fourteen was. Yeah, he's a little like a bingo card. He just from the calendar that he made with the trees and he holds it up in the light and that's how he determines it. It's not true. But what he did determine though, was which is really cool. And this is sort of what we've been building toward, is that most of your cells are about seven to ten years old, yes, in the body, and there are variances, and of course we're going to talk about all that, and right after this break, we're going to give you a little primer on cells. So you know what all this means, right, all right, Josh, we were promised to sell primer and we like to deliver on those promises. Here stuff you should know. So I guess we started off by saying they're thirty seven trillion cells about in the human body, give or take, and water makes up about two thirds the weight of those cells. Oh yeah, that's right. They're tiny. You need a microscope to seum and it's like it's the tiniest thing that can still reproduce. Yeah. And even though we have many different kinds of cells, I think two hundred types, and within those cells there are differences, but there are a lot of similarities with all cells in their structure. Um. Namely, they have a cell membrane, they have a nucleus. They have a nucleus. I have more than one. And these membranes are what allows nutrients to pass in and out, ways to pass out water through osmosis travels in reverse, osmosis travels out. Yeah. And what else you got your mitochondrian as well. That's where this is the important, really important thing, which is basically what keeps your cells alive. That's the power center, right yeah, and that's um. You know, your cells need food to live just like your body does. But you can't pass that that hamburger straight into your cell. It needs to be broken down so your cell can use it exactly into what adnosine triphosphate ATP is like the the universal cell fuel, right. Yeah. So there's a lot of stuff that the body does make I think you need like twenty three. I think you need twenty three amino acids, and like nine of them your body doesn't really manufacture. So those are the nine non essential amino acids. Right, And you use amino acids to build proteins, and use proteins for everything from making muscles to making red blood cells to um, you're mounting an immune response. Proteins are very, very vital, and some of them you have to build by eating stuff from your environment. Right. Yeah, So you go out and you find yourself a nice pig and you cut off its back leg. You say, sorry, pig, here's a peg leg for you. But I need this leg. I'm going to eat this leg. And what I'm really eating is the muscle, and what I'm really really eating is the glutamine. Yeah, and my body is going to take this glutamine. It can make it itself, but it doesn't hurt to have an extra little bit of glutamine. Yeah, it doesn't hurt to have that pig leg. And you're exactly right, So I'm chomping on the pig legs, like right, just use your imagination for a second, sure, um, And yes, I'm sorry too, uh, so you're eating the pig leg and you're gaining this glutamine as a result, and your body's metabolizing the glutamine and then reusing it, right, Yeah, And it can be glutamine, it can be um anything. We if we're ingesting a protein, if we're ingesting amino acids, before eating any kind of food, sugars, whatever, our bodies break it down into its constituent parts, and then a lot of those constituent parts become part of our bodies. Yeah. So if you think about it in this sense, when we eat, when we breathe, we're taking in stuff we need from the environment. Yeah, and that stuff that we take in from the environment becomes a part of us literally physically on the molecular level. It becomes a part of us, for better or worse, depending on what it is. Of course. Yeah, that's a that's a great I think that's ultimately one of the side lessons of this whole thing is we should take care of our environment because that environment becomes us and we either suffer or thrive as a result of it. You ever heard the expression you are what you eat exactly? You know, you literally are what you eat, quite literally, and then also chuck it goes. It goes the other way as well. When we excrete waste, when we exhale CO two that's taken up by other things in the environment, is deposited into the environment and it becomes part of the environment itself. Yeah. So not only do we regenerate our cells, regenerate tissue every on average seven to ten years, become almost wholly a new version of ourselves. Yea, we are also the boundary between us and the surrounding environment is really nonexistent because there's a constant exchange of molecules. Yeah, we lose on average, they say nine average adult male loses ninety six million cells per minute, but we also replace those at the rate of ninety six million per minute, yeah, roughly. Yeah. Yeah, so that's the good news. So we've got all these cells that we're losing, we've got all these new cells that are replacing them. And I think, like you said earlier before the break, that these the different types of cell and then hence different tissues regenerate at a different rate, right, Yeah, And they all have specialized jobs, and the cells are often built in such a way to aid that job physically, you know, different to make that job easier, which is really cool too. Shows how versatile they are. Yes, you know, like stem cells are very versatile. Super. So let's say your skin. Yeah, your skin regenerates every two to four weeks. I think, ye, so exactly, you get a new healthy coating of skin every two to four weeks because your epithelial cells are particularly good at regenerating themselves. That's right, and that is well. I guess that would fall on the low side obviously, if we're talking seven to ten years. On the super low side, you have the cells that line like you're intestine and your gut, and those things don't last long at all because it's such a harsh environment. You know, you would expect him to last like weeks and months and years, but I think, how long is it? Five days? Yeah, that's nothing. But the structure of your guts, they that are beneath that membrane lining that turns over five days, they last about fifteen years. Yeah, it's it's such a like a beautiful, elegant system. Yeah, that we have to keep us alive. Red blood cells last about one hundred and twenty days. But then you have things like cells in your bone which actually regenerate as well, so your bones are over time, over a much longer period of time, actually becoming I mean, I hate to call them new bones, but they kind of are, you know, well, yeah, I mean compared if you took your femur and somehow compared it to your femur when you were fifteen years old, Like, they are two totally different bones, even though they're your bones. Yeah, they were in the same place, growing in the same person with the same DNA. There's still different bones because they're made of different cells. Ten years or so for the bones, yeah, something like that. For the human skeleton, three hundred to five hundred days. For the liver, very important organ it is. And one of the other cool things about the liver is it's just gangbusters that regenerating itself. Yeah. You can apparently cut out ninety five percent of a person's liver and it will grow back, and you won't have full function, but it will function and you'll survive with just five percent of your liver. That's pretty amazing actually, yeah, because it will just grow right back, kind of like a hornet's nest. Uh. Interestingly, the inner lens cells of your eye um form in your embryo and basically don't change. Yeah, Now, is that why you have suffer from degeneration and vision? That's what I would guess. Is that the reason? Yeah, So with the corneo lens Chuck, when you're when you're born, when you're conceived, right, you are a cell that divides. Finally, once that first division takes place, those corneal cells, they're set in stone. Like your corneal cells are as old as you are, the same age as you. Other cells that make up different parts of the eyes they're far newer. But your corneal cells, your cerebral cortex cells, they think, Yeah, that's the one I mentioned. The brain and the heart muscles, those are the two big ones. Because obviously the reason we have diseases like Alzheimer's and dementia are because the cerebral cortex has long thought to not to regenerate cells at all. Now I think they believe that they do in a very small number or different regions, like the olfactory bulb supposedly does. Yeah, in the hippocampus, so we can learn new things. Our sense of smell can be refined over time. Yeah, And I think isn't that also the reason the smell is very much tied to your memory, probably like a smell can conjure up a memory more clearly. Yeah, but the cerebral quartex itself, they don't think. Who was her name? Elizabeth Gould Princeton did a lot of work on this because it was just basically set in stone for years like, no, it doesn't happen. And she did a lot of work over the years trying to prove that it did using tracer studies. And I think that where they are now as they think it does some yeah here there, here there, But obviously we still have to mention Alzheimer, so it's not it doesn't regenerate like the rest of the body. Name close. Yeah, Alzheimer's also maybe produced I guess by plaques rember plaque build up. Oh yeah, in between your neurons that keep them from firing as well. Yeah, that's it seems like we're so close to figuring out the secret, you know. Yeah, to uh, I don't know about not dying ever, I'm not talking immortality, but um, living much longer lives. Well, let's talk about that, because all of this stuff kind of leads to that question if we regenerate, so often why do we die? And we'll address that right after this. All right, So chuck Um, there's this kind of there's this idea that if we are regenerating ourselves every seven to ten years, where like the vast majority of our body cells regenerate, why do we age and why do we die? It doesn't it doesn't really make sense in that respect. Yeah, it's um. What they think is it has to do with your DNA actually in the cell. Our cells as we age, even the new ones to get replaced, which really stinks, become what they call sentisent, which means that they can't divide any longer. We've talked about the Hayflick limit before, or replicative citizens is basically how many times your cells can divide over its lifetime. Yeah, and I think like a fibroblast, which is the cells of the connective tissue in mammals, it's about fifty cell divisions. Yeah, and then it hits that point of senticence and it starts sending out repair signals to your body that aren't necessary and that causes inflammation. And we've talked about inflammation kind of being the source of most most of the original problems that will eventually lead to your debt. Yeah, you know. Yeah, something becomes inflamed and leads to all kinds of problems, so there's no repair needed. So it's a false signal. So they're trying to come up with drugs. Now, there's one called repamycine that pries to stop the cells from sending out those false signals, which is amazing. Yeah, that would be wonderful. You know. There's another explanation for it as well, is that when our cells divide, especially over time as we age, they're basically making photocopies of themselves. Yeah, and you ultimately, years down the road, end up making photocopies of photocopies and those don't tend to pan out very well. So as far as analogies go, that one kind of makes sense that, yes, we have brand new cells, but the DNA copies, the DNA blueprints that they're based on, have seen better days. Yeah, many years back. You know. Yeah, that makes sense. It's a good way to say it. We also talked a little bit about whether or not the heart muscle itself replenishes itself in the cells, and for a long time they had no idea. But um, now, thanks to our buddy doctor Frisson, He uh is pretty much. I don't even think we said what his um who he works with, did we? Uh? No, he works with the with A K. Carolinska team. Yeah, just like incredible scientists that are making like amazing advancements and trying to figure the stuff out. But they did, in fact find that the heart does replace itself the muscle cells. About one percent of the heart muscles replaced every year at age twenty five, and that falls over your lifetime to less than half a percent per year by the age seventy five. I spoke too soon. That does make sense. Yeah, So what they basically said is about half of your heart's muscle cells will be exchanged during a normal lifetime, Okay, which is okay, it is, but it's slowing down over time. I mean, the heart's kind of essential. Yeah, but they're hoping again to develop drugs that can accelerate that process too. Yeah. And I don't know how far along they are on that, but that'd be amazing. So there's this whole thing that kind and it came up to me man like that I don't all of this raises this question to me, right, Yeah, if you look at like you or me or any living thing as as an investment, like a molecular investment in the ability to reproduce. Right, Okay, once you finish your reproductive age, then it does make sense that you would just kind of there would be built in this mechanism of aging and then death and then decay, which is what we do. Yeah, we return back to the earth. To put it in kind of biblical terms, there's like that whole ashes to ashes dust to us thing. It is very very true. And if you look at us and you look at all living things as it is something that exchanges molecules with the external environment, takes them in, puts them out right, and you look at us as all connect acted in that sense. Yeah, like we're just like a plant exactly, or we're just like a rock, Like we're all that stuff and those things are us because we're able to exchange basic ingredients. Then it makes total sense that a person would come together, be conceived, start dividing as cells, you know, make more of itself, and then start to age and then die in decay, and then it would give something else a chance to come up from that again. Right, sure, but then it makes you it makes you wonder what's the point of that? What I mean, like, think about it. If we're just the same as plants, Like why are we all here? Yeah, Like, if we're if the whole point is to just basically recycle materials, because we are just recycling stuff from the environment, and we're recycled as we die in decay, what is the point? Is our point just to be part of the carbon cycle, so we're moving carbon in and out of ourselves and in and out of the environment, moving it around. Or I don't understand what the point is of life, I guess is what I'm saying here nihilists. No, I'm not saying I don't believe that there isn't a point. I'm just curious what it is. Because because if we are the same as any other living thing, and the definition of living is an exchange with an active exchange with the surrounding environment and breathing, true, eating whatever, yes, then and then if you kind of take that a little further and say, well, clearly we're meant to like reproduce or something like that, and then after that we age and die, what's the what's the point? Like why not just have one species? Of living thing and just let that do all of your carbon recycling or whatever. Yeah, I think are you about to quit the show? Um? Yeah, see what you mean? Like, um, if we look at ourselves as a purely mechanical serving a purely mechanical function right on the planet, like we are to the carbon cycle, what say evaporation is to the rain cycle? Yeah, like we're a means of moving something along. Well, I think that's when you, man, this is getting philosophical. I think that's when you start getting into questions of the soul. Well yeah, I mean it kind of makes me wonder, like, well, why would there be more than one species? It will be much more efficient to just have one, maybe two. There's all these different ones, so why. Yeah, the fact that that why is just sitting there and flashing neon lights definitely made me wonder basically the opposite. It's made me think in a different direction than nihilistically, right, you know, like we're only here for so long, and so if there is the point is to make the most of your time, well I think that's a separate that's a separate part of it. Yeah, Because no matter what conclusion you come to, whether nope, we're just a means of recycling carbon and that is it. Yeah, kind of like a Guya theory view of things. Or if you say no, like the fact that we're inefficient and redundant as far as that carbon recycling thing goes, Yeah, suggests that maybe there is a higher purpose to us. Either way, I feel like you come to the conclusion, or you should come to the conclusion that the one thing we do know is that we are here right now, and the best thing we can do is make the absolute best of it for ourselves and for other people as well. Yeah, and there are probably others out there that think the whole point is to make as much cash as you can so you can buy products. Yeah, Edward Burns would probably say that, Yes, he would. Man, he lived that way then, Man, that's interesting. I think we should. I'd love to tackle something philosophical and deep, like the soul, the meaning of life. Yeah, that'd be tough. I mean that'd be cool, though, it would be cool. We don't delve into that very much, No, we should. I'd like to do that. And consciousness that's a really interesting one too, Like it doesn't make any sense a sense, very trippy way forward. For this show. Yeah, we're gonna start getting weird. I took a lot of acid this morning. So that's great if you want to know more about some just weird trippy stuff. How stuff works has a surprising amount of it on there. Um, I don't know. Just try typing the word trippy into the search bar. You can also type does your body really replace itself every seven years? And it'll bring up this cool article. And I think I said search bar at some point in time. So how about some listener mail. I like how you specified you took a lot of acid, not just just a little. Yeah, there's a lot out of it. Um, all right, I'm gonna call this multiple we had. We got like a bunch of emails in one day about people picking at our grammar and things. Oh yeah, so I'm just decorded to read three of them because they're short. Okay, hey, guys, I generally enjoy the episodes, but you do have one issue with your grammar and noun verb agreement. You tend to say they're are many lines of evidence or there's lots of experiment showing, instead of there are not. There is boo when the pronoun refers to a plural subject. Check yourselves next time, guys. You typically make the mistake about ten times every show. Why don't you go recycle some carbon power. That's from Kim Keller in Temple Terrorists, Florida. I always like to pick apart their emails too, about because people usually make a mistake or two in their own emails. Hey, guys, system's from Blair. I love the show. I hate to be nitpicky. They always say that, yeah, right before they knitpick. But I have a grammar correction. It's been bugging me for months, and Stonehenge was a major offender. At least one of you not naming names frequently used the word further when you really mean farther. The latter term is used for literal distances. Further is only supposed to be used figuratively. Huh. I didn't know that, Okay, so thanks Blair. Yeah. And then the last one, Phil, who was an English and grammar pronunciation freak, He says, hey, guys, when there's an Italian word, you take your time to pronounce it properly. The same with Japanese in the Far East in general. So why don't you extend that same courtesy to English words? Because we're masters of the language, and I mean words actually in the UK vernacular, not American English. Salisbury, No, it's Salisbury, the marl Borough Downs, Nope, marl Browdowns. Well, we're using the American vernacular because we're in America and recording as American. That's from Phil I had. I've addressed all those. I think, yeah, I think that's I feel good about it. I think it's good and very big of you two have read those as listener mail. Why not? Nice job man? Yeah, we just we don't profess to talk gooder than other people. We just do our little thing here in the studio, send it out into the world nice for people to pick apart. What we're doing is we're creating grammatical tableaus like that Highlights Magna ze, where it's like pick out the things that don't belong. Yeah, that's what we're doing for you guys. Yeah, keep you entertained. If you didn't have something to complain about it, it'd be so boring. Yep. If you want to nitpick or compliment or suggest something whatever. If you want to get in touch with us for any reason, you can do that by tweeting to SYSK podcasts. You can join us on Facebook, dot com slash Stuff you Should Know. You can send us an email to Stuff Podcast at HowStuffWorks dot com, and as always, join us at our home on the web. Stuff you Should Know dot com. Stuff you Should Know is a production of iHeartRadio. For more podcasts my Heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.

Welcome to Stuff you should know, a production of iHeartRadio. Hey, and welcome to the podcast. I'm Josh Clark with Charles W. Chuck Bryant, and guest producer Noel Noels in the house. It's the It and the New Studio. Yeah, man, this place is comfy, cozy. I like it. I wish um, you know, I wish there was a chair version of a water bed. I know this is a nappish little place. Yeah, especially today, I think I'm I'm dragging all apologies. Yeah, same here. So if we're talking kind of slow or low, or we just stopped talking for a little while, it's where its tired. Yeah. We bumped into you at the Hawks game last night. I know. Hey, how many does that you know? Yeah? Just the bumping. Yep, we were both at the Hawks. Gammy in the Hawks. One didn't even know we were going. No. Look over in the line. There's Josh and Yumi. Yeah that's great. There's Chuck and Eddie yep, each other in an arena of eighteen thousand bumping into someone. Is that it? That's all it holds. I think it's something like that. It's a good a lot of people. It's a good arena. Yeah, but you had box seats because you're special. They were free o. Mine were free to in. The nosebleeds Yeah, I like just about every seat in that place. Yeah, it's not too bad. I was. I was laughing about the nosebleeds going in, But then I got up there. I was like, this is great. Yeah you can see everything. Did your nose actually bleed just twice? Yeah, once out of a cheer excitement, and then once from the altitude and that was more of a spray, right yeah, yeah, just covering everyone. Everyone was like hawks, Boy, what a weird intro. It's a little weird, um, But I mean it kind of jibes a little bit because we're talking. Yeah, you're mentioning blood. Sure, I was shedding cells and blood. You were like blood is made up of sell and we shed tons of cells. But before we get to that, right, there's the fact of the podcast. You shed cells. Um. I want to mention this one thing I read. Yeah, it's called I think the title of the article is the Self is Moral. It's about like where we get our identity of self from, like where it's rooted. It was written by a person named Nina Stromeyer, I believe is on aon magazine. Just type in the self is moral aon It'll come up. I'll get you there. Uh and uh. It Towards the beginning, the author says, there's this very famous philosophical exercise, which you know, philosophers love to do, like mental exercises. Yeah, that's what that's all they have. So imagine you have like kind of imagine you have like a ship, right, like a boat, ye, a nice Yankee clipper okay, okay, And this Yankee clipper is slowly, over time kind of salvage for parts, okay, but rather than just being stripped, like every time a part is taken out, it's replaced and then over the course of like fifty one hundred years, as each plank, as each bolt, as each like masked head, even the thing the carved lady in front, yeah, eventually just gets replaced with something else. Yeah, a new carved lady that speaks of the time, right, you know? Is it still though, after every single part has been replaced, the same ship that it was before? Yeah, I see what you mean. I don't think that can be possible. Why not, especially if it has the same name and it's the same ship in the same place as before. It was just slowly, over time moved out. True, where does the self lie? Yeah, that's a good point, man, Like redoing a house, same thing, Yeah, I mean all the floors and the walls and the windows, Like when does it cease to become that same house that was built in nineteen thirty exactly? Isn't that cool? Yeah? It is really cool. And the reason that it applies to this episode is because over the course of your lifetime, a significant portion pretty much all of the cells in your body are going to like be replaced. Yeah, so that the the person even after you reach your adult self. Yeah, physically, by the time you die, assuming you're gonna die much later, you're you are essentially a different person, at least on the cellular level. Yeah. Thirty seven trillion cells ish, that's how many we have. Yeah, that's what they estimate. And I did a little looking into lifespans. Sounds like an estimate thirty seven trillions. Yeah, what do you want, like like give or take? Yeah, I did a little research into lifespans just because this all sort of comes back to, like your death basically, because that's all death is is your your cells, you know, dying little by little. Well, yeah, I mean if you think about it, chuck, one of the things that like why do we die? If our we'll get to all that, but it's intriguing, you know, it started, you know, questions started popping up. So apparently we gain about three months every three months of life humanity every year that we progress, Like the average lifespans spans by three months. Yeah, Like if you were born in twenty twelve, the average lifespan is now and this is the United States, is seventy eight point eight. If you were born in nineteen oh one, it was about forty seven and fifty years for men and women respectively. But if you look at the ratio, it's still about three months. Despite all our technologies, three months a year, every year, every year, just slowly creeping along. Yeah, Because I think the article it was like when we're going to live to be one hundred by average, and they say by the year twenty one hundred, if things hold, then the average human or American will be about one hundred years old. I thought that, so I guess that if things are steadily progressing, I had heard that like our generation would be either the last or the first, the last two to not hit triple digits or the first two on average. Yeah. Yeah, again these are all guesses, you know, so who knows. Plus if you believe in like, uh things, speeding science, speeding up? Yeah, what is that? Moore's law? Yea is at it? Yeah, applied to computer or though in that case right right, but I mean you can send it to other stuff. Yeah, then you might think, you know, it's it's but you know, they say it's not increasing like that. No, at least not so far. Moore's law is exponential growth just adding three months every years, non exponentials geometric. I think we're still at non exponential growth definitely. Yeah, we're just adding three months. Yeah, it's not bad though. That's pretty good average every four years. That's an extra year. Yeah. Well, and it's interesting to think about, you know, people that were born you know a lot of our colleagues like eight years behind us. We're going to live an average of two years longer. Yeah, that seems unfair, sad. Yeah, I know, what did they do? Just observe that we're thinking about our own deaths today. Yeah, and chuck that there's this rumor theory legend maybe okay, that your body regenerates itself, of your body regenerates itself every year. Yeah, that's not true. No, it's not true, but it was a very long standing rumor, and it was actually based on science. Yeah, you know, not just the idea that, oh, yeah, ourselves regenerate. So back of the envelope estimate is that, you know, we regenerate ninety five or ninety eight percent of ourselves every year. It was early experimentation by injecting radio act of isotopes into human beings and then following their course and then making estimates based on that led to this idea. It's called pulse labeling, is it. Yeah. It's like tagging an animal in the wild basically, right, but you're just tagging a cell, yeah, for specific types of cell. Yeah. They don't do that to humans anymore. No, it's very animals anything. It's a very dumb thing to do. Sure, ejecting radiation exactly, Yeah, unless, of course you know it's radiation treatment. That's true, which is still a really weird thing if you think about it. It's Yeah, I have a feeling it's gonna be like one of those things we look back on as like a primitive treatment. Yeah, yeah, yeah, I hope so. Um, but there there was this long standing science for decades or this idea, scientific idea that we regenerated ourselves by finally, and I think two thousand five, Um, there was a a researcher named doctor Jonas Freezing. He was Swedish. Dude's awesome. He said, this whole urban legend is really bringing me down. I want to figure out a way to really track how often the human body regenerates itself. Yeah, and the biggest question has been the brain, specifically the cerebral cortex and the heart and the heart muscles. I mean, they want to know all this stuff, but those were the two biggest mysteries. I think. Right, there's still the mysteries. But if you went back to prior to two thousand and five, in doctor Freeson's research, it was all a mystery. Yeah, he figured out he basically put a very accurate time stamp on how often human tissue and human cells regenerate themselves. Right, So the way he did this is very clever. For a long time, botanists knew that the trees around the world contained a spike of carbon fourteen radiation, Yes, thanks to humans and nuclear bombs. Exactly from nineteen fifty four to nineteen sixty three, tree rings for tree growth around the world show a big spike in carbon fourteen. Carbon fourteen is naturally occurring too, So like just cosmic rays from the Sun bombard Earth's atmosphere and create radioactive isotopes by knocking electrons from particles in our atmosphere, right, those radioactive particles become carbon fourteen, which is radioactive, and in the atmosphere, carbon fourteen binds to oxygen and creates carbon dioxide, which comes to Earth. Every living thing breathes this stuff in, whether it's a plant, whether it's a human, Like we just have C fourteen in our bodies. We also eat plants exactly contain the C fourteen bids breathing it in, and we also eat the animals that eat the plants that in just C fourteen. Right, Yeah, so like we got CAR fourteen in our bodies, that's right. But because of the spike in carbon fourteen that was introduced to the atmosphere from nuclear testing there there is a spike in humans as well. So you can roughly age like a human compared to another human if they were born in say nineteen fifty nine, and one who was born in nineteen seventy after there was that spike of carbon fourteen had gone away, right, right, that's pretty cool. But what doctor Freezen did is even cooler. He basically went back to those tree trunks, those tree rings that show a spike in carbon fourteen, and created a calendar of carbon fourteen to Kay and basically said, Okay, on this date, this is how much carbon fourteen was on Earth. And if I take this cell and compare it, knowing that carbon fourteen decays at a constant rate, yeah, I can tell you exactly how old this cell is exactly. And he used it to date cells and tissues and all sorts of cool stuff. Yeah. He he went looking for a marker and he found one due to our atomic testing program. Yeah, which is pretty weird. Just released all that junk in the atmosphere, and now all these years later it has a nice use. Yeah, you know it does. So we now know when we're gonna die, right, And the reason he was able to use this as a marker, Chuckers, is that, um, when you when you take a breath of life, your first breath of life. That's right, and you get some you get some of that C fourteen into your DNA um and a steady amount stays in there, like you don't keep ingesting C fourteen as far as I understand, as far as your DNA goes, Oh okay, once it's in your DNA, as your cells divide, yeah, that original amount becomes divided evenly. Right, So the less C fourteen that's in tissue, the older those that cell line, is right, or the younger the actual cells are, right? Is that right? I think so? Which would mean the new cell the marker would be a fresh batch of the C fourteen. No, it have less C fourteen? Oh really? Yeah, let's say you have because the cell divided, Yes, exactly, Yeah, like you have ten grams of C fourteen, which you don't. I can't imagine that would be Like let's say you're you're one cell that's never divided has ten Yeah, when it divides into two, it's each of those two cells is going to have five grants, and then two and a half and then one point seven five and so on and so on. Um, So, since you know that C fourteen is generated at a constell rate, you know that it decays that a half life of fifty seven hundred and thirty years. You can look at the amount of C fourteen and then also the decay of it as well. Yeah, you can date things that are no longer living too, to see when when they ingested that C fourteen was. Yeah, he's a little like a bingo card. He just from the calendar that he made with the trees and he holds it up in the light and that's how he determines it. It's not true. But what he did determine though, was which is really cool. And this is sort of what we've been building toward, is that most of your cells are about seven to ten years old, yes, in the body, and there are variances, and of course we're going to talk about all that, and right after this break, we're going to give you a little primer on cells. So you know what all this means, right, all right, Josh, we were promised to sell primer and we like to deliver on those promises. Here stuff you should know. So I guess we started off by saying they're thirty seven trillion cells about in the human body, give or take, and water makes up about two thirds the weight of those cells. Oh yeah, that's right. They're tiny. You need a microscope to seum and it's like it's the tiniest thing that can still reproduce. Yeah. And even though we have many different kinds of cells, I think two hundred types, and within those cells there are differences, but there are a lot of similarities with all cells in their structure. Um. Namely, they have a cell membrane, they have a nucleus. They have a nucleus. I have more than one. And these membranes are what allows nutrients to pass in and out, ways to pass out water through osmosis travels in reverse, osmosis travels out. Yeah. And what else you got your mitochondrian as well. That's where this is the important, really important thing, which is basically what keeps your cells alive. That's the power center, right yeah, and that's um. You know, your cells need food to live just like your body does. But you can't pass that that hamburger straight into your cell. It needs to be broken down so your cell can use it exactly into what adnosine triphosphate ATP is like the the universal cell fuel, right. Yeah. So there's a lot of stuff that the body does make I think you need like twenty three. I think you need twenty three amino acids, and like nine of them your body doesn't really manufacture. So those are the nine non essential amino acids. Right, And you use amino acids to build proteins, and use proteins for everything from making muscles to making red blood cells to um, you're mounting an immune response. Proteins are very, very vital, and some of them you have to build by eating stuff from your environment. Right. Yeah, So you go out and you find yourself a nice pig and you cut off its back leg. You say, sorry, pig, here's a peg leg for you. But I need this leg. I'm going to eat this leg. And what I'm really eating is the muscle, and what I'm really really eating is the glutamine. Yeah, and my body is going to take this glutamine. It can make it itself, but it doesn't hurt to have an extra little bit of glutamine. Yeah, it doesn't hurt to have that pig leg. And you're exactly right, So I'm chomping on the pig legs, like right, just use your imagination for a second, sure, um, And yes, I'm sorry too, uh, so you're eating the pig leg and you're gaining this glutamine as a result, and your body's metabolizing the glutamine and then reusing it, right, Yeah, And it can be glutamine, it can be um anything. We if we're ingesting a protein, if we're ingesting amino acids, before eating any kind of food, sugars, whatever, our bodies break it down into its constituent parts, and then a lot of those constituent parts become part of our bodies. Yeah. So if you think about it in this sense, when we eat, when we breathe, we're taking in stuff we need from the environment. Yeah, and that stuff that we take in from the environment becomes a part of us literally physically on the molecular level. It becomes a part of us, for better or worse, depending on what it is. Of course. Yeah, that's a that's a great I think that's ultimately one of the side lessons of this whole thing is we should take care of our environment because that environment becomes us and we either suffer or thrive as a result of it. You ever heard the expression you are what you eat exactly? You know, you literally are what you eat, quite literally, and then also chuck it goes. It goes the other way as well. When we excrete waste, when we exhale CO two that's taken up by other things in the environment, is deposited into the environment and it becomes part of the environment itself. Yeah. So not only do we regenerate our cells, regenerate tissue every on average seven to ten years, become almost wholly a new version of ourselves. Yea, we are also the boundary between us and the surrounding environment is really nonexistent because there's a constant exchange of molecules. Yeah, we lose on average, they say nine average adult male loses ninety six million cells per minute, but we also replace those at the rate of ninety six million per minute, yeah, roughly. Yeah. Yeah, so that's the good news. So we've got all these cells that we're losing, we've got all these new cells that are replacing them. And I think, like you said earlier before the break, that these the different types of cell and then hence different tissues regenerate at a different rate, right, Yeah, And they all have specialized jobs, and the cells are often built in such a way to aid that job physically, you know, different to make that job easier, which is really cool too. Shows how versatile they are. Yes, you know, like stem cells are very versatile. Super. So let's say your skin. Yeah, your skin regenerates every two to four weeks. I think, ye, so exactly, you get a new healthy coating of skin every two to four weeks because your epithelial cells are particularly good at regenerating themselves. That's right, and that is well. I guess that would fall on the low side obviously, if we're talking seven to ten years. On the super low side, you have the cells that line like you're intestine and your gut, and those things don't last long at all because it's such a harsh environment. You know, you would expect him to last like weeks and months and years, but I think, how long is it? Five days? Yeah, that's nothing. But the structure of your guts, they that are beneath that membrane lining that turns over five days, they last about fifteen years. Yeah, it's it's such a like a beautiful, elegant system. Yeah, that we have to keep us alive. Red blood cells last about one hundred and twenty days. But then you have things like cells in your bone which actually regenerate as well, so your bones are over time, over a much longer period of time, actually becoming I mean, I hate to call them new bones, but they kind of are, you know, well, yeah, I mean compared if you took your femur and somehow compared it to your femur when you were fifteen years old, Like, they are two totally different bones, even though they're your bones. Yeah, they were in the same place, growing in the same person with the same DNA. There's still different bones because they're made of different cells. Ten years or so for the bones, yeah, something like that. For the human skeleton, three hundred to five hundred days. For the liver, very important organ it is. And one of the other cool things about the liver is it's just gangbusters that regenerating itself. Yeah. You can apparently cut out ninety five percent of a person's liver and it will grow back, and you won't have full function, but it will function and you'll survive with just five percent of your liver. That's pretty amazing actually, yeah, because it will just grow right back, kind of like a hornet's nest. Uh. Interestingly, the inner lens cells of your eye um form in your embryo and basically don't change. Yeah, Now, is that why you have suffer from degeneration and vision? That's what I would guess. Is that the reason? Yeah, So with the corneo lens Chuck, when you're when you're born, when you're conceived, right, you are a cell that divides. Finally, once that first division takes place, those corneal cells, they're set in stone. Like your corneal cells are as old as you are, the same age as you. Other cells that make up different parts of the eyes they're far newer. But your corneal cells, your cerebral cortex cells, they think, Yeah, that's the one I mentioned. The brain and the heart muscles, those are the two big ones. Because obviously the reason we have diseases like Alzheimer's and dementia are because the cerebral cortex has long thought to not to regenerate cells at all. Now I think they believe that they do in a very small number or different regions, like the olfactory bulb supposedly does. Yeah, in the hippocampus, so we can learn new things. Our sense of smell can be refined over time. Yeah, And I think isn't that also the reason the smell is very much tied to your memory, probably like a smell can conjure up a memory more clearly. Yeah, but the cerebral quartex itself, they don't think. Who was her name? Elizabeth Gould Princeton did a lot of work on this because it was just basically set in stone for years like, no, it doesn't happen. And she did a lot of work over the years trying to prove that it did using tracer studies. And I think that where they are now as they think it does some yeah here there, here there, But obviously we still have to mention Alzheimer, so it's not it doesn't regenerate like the rest of the body. Name close. Yeah, Alzheimer's also maybe produced I guess by plaques rember plaque build up. Oh yeah, in between your neurons that keep them from firing as well. Yeah, that's it seems like we're so close to figuring out the secret, you know. Yeah, to uh, I don't know about not dying ever, I'm not talking immortality, but um, living much longer lives. Well, let's talk about that, because all of this stuff kind of leads to that question if we regenerate, so often why do we die? And we'll address that right after this. All right, So chuck Um, there's this kind of there's this idea that if we are regenerating ourselves every seven to ten years, where like the vast majority of our body cells regenerate, why do we age and why do we die? It doesn't it doesn't really make sense in that respect. Yeah, it's um. What they think is it has to do with your DNA actually in the cell. Our cells as we age, even the new ones to get replaced, which really stinks, become what they call sentisent, which means that they can't divide any longer. We've talked about the Hayflick limit before, or replicative citizens is basically how many times your cells can divide over its lifetime. Yeah, and I think like a fibroblast, which is the cells of the connective tissue in mammals, it's about fifty cell divisions. Yeah, and then it hits that point of senticence and it starts sending out repair signals to your body that aren't necessary and that causes inflammation. And we've talked about inflammation kind of being the source of most most of the original problems that will eventually lead to your debt. Yeah, you know. Yeah, something becomes inflamed and leads to all kinds of problems, so there's no repair needed. So it's a false signal. So they're trying to come up with drugs. Now, there's one called repamycine that pries to stop the cells from sending out those false signals, which is amazing. Yeah, that would be wonderful. You know. There's another explanation for it as well, is that when our cells divide, especially over time as we age, they're basically making photocopies of themselves. Yeah, and you ultimately, years down the road, end up making photocopies of photocopies and those don't tend to pan out very well. So as far as analogies go, that one kind of makes sense that, yes, we have brand new cells, but the DNA copies, the DNA blueprints that they're based on, have seen better days. Yeah, many years back. You know. Yeah, that makes sense. It's a good way to say it. We also talked a little bit about whether or not the heart muscle itself replenishes itself in the cells, and for a long time they had no idea. But um, now, thanks to our buddy doctor Frisson, He uh is pretty much. I don't even think we said what his um who he works with, did we? Uh? No, he works with the with A K. Carolinska team. Yeah, just like incredible scientists that are making like amazing advancements and trying to figure the stuff out. But they did, in fact find that the heart does replace itself the muscle cells. About one percent of the heart muscles replaced every year at age twenty five, and that falls over your lifetime to less than half a percent per year by the age seventy five. I spoke too soon. That does make sense. Yeah, So what they basically said is about half of your heart's muscle cells will be exchanged during a normal lifetime, Okay, which is okay, it is, but it's slowing down over time. I mean, the heart's kind of essential. Yeah, but they're hoping again to develop drugs that can accelerate that process too. Yeah. And I don't know how far along they are on that, but that'd be amazing. So there's this whole thing that kind and it came up to me man like that I don't all of this raises this question to me, right, Yeah, if you look at like you or me or any living thing as as an investment, like a molecular investment in the ability to reproduce. Right, Okay, once you finish your reproductive age, then it does make sense that you would just kind of there would be built in this mechanism of aging and then death and then decay, which is what we do. Yeah, we return back to the earth. To put it in kind of biblical terms, there's like that whole ashes to ashes dust to us thing. It is very very true. And if you look at us and you look at all living things as it is something that exchanges molecules with the external environment, takes them in, puts them out right, and you look at us as all connect acted in that sense. Yeah, like we're just like a plant exactly, or we're just like a rock, Like we're all that stuff and those things are us because we're able to exchange basic ingredients. Then it makes total sense that a person would come together, be conceived, start dividing as cells, you know, make more of itself, and then start to age and then die in decay, and then it would give something else a chance to come up from that again. Right, sure, but then it makes you it makes you wonder what's the point of that? What I mean, like, think about it. If we're just the same as plants, Like why are we all here? Yeah, Like, if we're if the whole point is to just basically recycle materials, because we are just recycling stuff from the environment, and we're recycled as we die in decay, what is the point? Is our point just to be part of the carbon cycle, so we're moving carbon in and out of ourselves and in and out of the environment, moving it around. Or I don't understand what the point is of life, I guess is what I'm saying here nihilists. No, I'm not saying I don't believe that there isn't a point. I'm just curious what it is. Because because if we are the same as any other living thing, and the definition of living is an exchange with an active exchange with the surrounding environment and breathing, true, eating whatever, yes, then and then if you kind of take that a little further and say, well, clearly we're meant to like reproduce or something like that, and then after that we age and die, what's the what's the point? Like why not just have one species? Of living thing and just let that do all of your carbon recycling or whatever. Yeah, I think are you about to quit the show? Um? Yeah, see what you mean? Like, um, if we look at ourselves as a purely mechanical serving a purely mechanical function right on the planet, like we are to the carbon cycle, what say evaporation is to the rain cycle? Yeah, like we're a means of moving something along. Well, I think that's when you, man, this is getting philosophical. I think that's when you start getting into questions of the soul. Well yeah, I mean it kind of makes me wonder, like, well, why would there be more than one species? It will be much more efficient to just have one, maybe two. There's all these different ones, so why. Yeah, the fact that that why is just sitting there and flashing neon lights definitely made me wonder basically the opposite. It's made me think in a different direction than nihilistically, right, you know, like we're only here for so long, and so if there is the point is to make the most of your time, well I think that's a separate that's a separate part of it. Yeah, Because no matter what conclusion you come to, whether nope, we're just a means of recycling carbon and that is it. Yeah, kind of like a Guya theory view of things. Or if you say no, like the fact that we're inefficient and redundant as far as that carbon recycling thing goes, Yeah, suggests that maybe there is a higher purpose to us. Either way, I feel like you come to the conclusion, or you should come to the conclusion that the one thing we do know is that we are here right now, and the best thing we can do is make the absolute best of it for ourselves and for other people as well. Yeah, and there are probably others out there that think the whole point is to make as much cash as you can so you can buy products. Yeah, Edward Burns would probably say that, Yes, he would. Man, he lived that way then, Man, that's interesting. I think we should. I'd love to tackle something philosophical and deep, like the soul, the meaning of life. Yeah, that'd be tough. I mean that'd be cool, though, it would be cool. We don't delve into that very much, No, we should. I'd like to do that. And consciousness that's a really interesting one too, Like it doesn't make any sense a sense, very trippy way forward. For this show. Yeah, we're gonna start getting weird. I took a lot of acid this morning. So that's great if you want to know more about some just weird trippy stuff. How stuff works has a surprising amount of it on there. Um, I don't know. Just try typing the word trippy into the search bar. You can also type does your body really replace itself every seven years? And it'll bring up this cool article. And I think I said search bar at some point in time. So how about some listener mail. I like how you specified you took a lot of acid, not just just a little. Yeah, there's a lot out of it. Um, all right, I'm gonna call this multiple we had. We got like a bunch of emails in one day about people picking at our grammar and things. Oh yeah, so I'm just decorded to read three of them because they're short. Okay, hey, guys, I generally enjoy the episodes, but you do have one issue with your grammar and noun verb agreement. You tend to say they're are many lines of evidence or there's lots of experiment showing, instead of there are not. There is boo when the pronoun refers to a plural subject. Check yourselves next time, guys. You typically make the mistake about ten times every show. Why don't you go recycle some carbon power. That's from Kim Keller in Temple Terrorists, Florida. I always like to pick apart their emails too, about because people usually make a mistake or two in their own emails. Hey, guys, system's from Blair. I love the show. I hate to be nitpicky. They always say that, yeah, right before they knitpick. But I have a grammar correction. It's been bugging me for months, and Stonehenge was a major offender. At least one of you not naming names frequently used the word further when you really mean farther. The latter term is used for literal distances. Further is only supposed to be used figuratively. Huh. I didn't know that, Okay, so thanks Blair. Yeah. And then the last one, Phil, who was an English and grammar pronunciation freak, He says, hey, guys, when there's an Italian word, you take your time to pronounce it properly. The same with Japanese in the Far East in general. So why don't you extend that same courtesy to English words? Because we're masters of the language, and I mean words actually in the UK vernacular, not American English. Salisbury, No, it's Salisbury, the marl Borough Downs, Nope, marl Browdowns. Well, we're using the American vernacular because we're in America and recording as American. That's from Phil I had. I've addressed all those. I think, yeah, I think that's I feel good about it. I think it's good and very big of you two have read those as listener mail. Why not? Nice job man? Yeah, we just we don't profess to talk gooder than other people. We just do our little thing here in the studio, send it out into the world nice for people to pick apart. What we're doing is we're creating grammatical tableaus like that Highlights Magna ze, where it's like pick out the things that don't belong. Yeah, that's what we're doing for you guys. Yeah, keep you entertained. If you didn't have something to complain about it, it'd be so boring. Yep. If you want to nitpick or compliment or suggest something whatever. If you want to get in touch with us for any reason, you can do that by tweeting to SYSK podcasts. You can join us on Facebook, dot com slash Stuff you Should Know. You can send us an email to Stuff Podcast at HowStuffWorks dot com, and as always, join us at our home on the web. Stuff you Should Know dot com. Stuff you Should Know is a production of iHeartRadio. For more podcasts my Heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.