SciShow Tangents - Immortality with Deboki Chakravarti

Episode Date: February 9, 2021

True immortality may be a scientific impossibility, but podcasts last forever. Whether you listen to this the day it comes out or 1,000 years from now when your brain’s been uploaded to a computer, SciShow Tangents will be here for you!This week: Hank and Deboki are finally on an episode together! And Hank has yet another chaos-fuled game to present to us!  Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Deboki: @okidoki_boki Ceri: @ceriley Sam: @slamschultz Hank: @hankgreenIf you want to learn more about any of our main topics, check out these links:[Fact Off]Irradiating canned meatWIll update ASAP!Dermestid beetle larvaehttps://science.sciencemag.org/content/sci/178/4066/1210.full.pdfhttps://academic.oup.com/aesa/article-abstract/64/1/149/28541?redirectedFrom=fulltexthttps://www.sciencedirect.com/science/article/abs/pii/002219108090027Xhttps://hortnews.extension.iastate.edu/warehouse-beetle-and-cabinet-beetleElectron decayhttps://gizmodo.com/electron-lifespan-is-at-least-5-quintillion-times-the-1747606990https://physicsworld.com/a/electron-lifetime-is-at-least-66000-yottayears/[Ask the Science Couch]Cryonicshttps://www.newscientist.com/article/2095072-a-visual-tour-of-the-weird-world-of-the-cryogenically-frozen/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2729856/https://pubmed.ncbi.nlm.nih.gov/2249453/https://www.theguardian.com/us-news/2020/sep/30/egg-freezing-self-care-pregnancy-fertilityhttps://www.npr.org/templates/story/story.php?storyId=130293211

Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase. I am your host, Hank Green, and today joining me as always is our science expert, Sari Reilly. Hello. Expert is a very generous term. And also our resident everyman, Sam Schultz. G'day, mate. Oh, gosh.

With the reboot of the show, I'm going to adopt a new personality and accent. Like every episode or like from now on, you're going to be Australian? I don't know. Whatever. Whatever happens, happens. Well, you've already lost it. Finally, our special guest for the week, Sasha Tangent's editorial assistant, Deboki Trocker-Vardy. Hello, Deboki.

Hello. Deboki helps make all kinds of things, hosts Crash Course Organic Chemistry, also helps me answer the science-y questions on Dear Hank and John, sometimes on my TikTok. But more than any of that is always here helping us at Tangents, make sure we get stuff right, and answer questions when we're confused. So, Deboki, I appreciate you for coming out. And all three of you, I want to ask you a question because of the topic for today's episode. If you could know when you were going to die, would you sign that contract?

Somebody comes up, like a man. He looks very mysterious. He's glowing. And he says, hello, I have a, like, you have to say yes or no right now. Do you want to know when you're going to die? You can't do anything to prevent it. You can't take any, like, you can, like, live your life differently. But you're going to die on this day, and now you know. You don't know how it's going to happen?

You don't know how it's going to happen. Is the man telling the truth? The man is telling the truth. You guys are asking a lot of questions for me. I'm just like, no. I have no interest in knowing. Yes, I would do it. I think I would do it too.

I don't think it would change anything. Well, I guess that's hard to say because I won't know, but. Yeah. I think the real gamble is if you're going to die of natural causes or not. And that would be the thing that you'd find out that would be like, oh, shoot. Yeah. If it's 10 years from now, you're like, oh, that's not.

Yeah. So Deboki, tell me what you think of my reasoning here. I feel like the worst part for me about the fact that I'm going to die is that it could happen at any time. Yes. I don't mind the idea of dying. Like that's good enough for everybody else so far. I should be okay with it.

But I want to be able to plan. I feel like that's a big life event to have no control over. Yeah. I don't know that knowing when you're going to die is really going to give you the sense of control that any of us are seeking from any knowledge of death. It's going to feel like control. But at the end of the day i just oh the idea of knowing when i'm gonna die i like you guys were saying earlier like it wouldn't change anything i know for me it would change everything like i would it would totally change i i could not live comfortably and like just the countdown oh it

would be too much for me to handle you do already have a piece of knowledge that is similar, which is that you will die. Not proven, but true. I am so sure that I would learn and then forget so fast. Like I'd be really productive for like two weeks and then I would just forget and be like, oh, well. Yeah, and then somebody asks you and they're like, you found out from the guy who tells you when you die, right?

He came to you. And you're like, yeah, but I spaced it. It was sometime later. Like, it wasn't around now. So I just spaced it. Yeah. I feel like for me, and maybe this says a lot about me in ways that I don't know, it would be like any other sort of important date of like oh i'm graduating for college in four years counting down to that and then it's giving me another milestone to look forward to as opposed

i guess not look forward to but just to like count down to because i'm out of those i'm out of formal schooling which gave me plenty of like nice milestones of like i can be done with this sari riley just wants another deadline. That's the thing I was thinking about is like also in terms of planning, like knowing that like, okay, this is the date that I'm planning for. I mean, I know myself

and I know that either way I'm going to wait for the last moment. So I might as well not know what that last moment is. Well, that's a great point. You are winning me over a little bit that the, the reality is that the worst feeling is knowing that you procrastinated up to the point of your actual death.

It's like, like for me, I can be like, well, I didn't, I didn't make it to Ireland, but I didn't know. I didn't know if I was going to die or live, but, but if I die and like, I knew it and I was like, man, like it was on my bucket list and I just didn't know if I was going to die or live, but if I die and I knew it and I was like, man, it was on my bucket list and I just didn't fucking do it. I knew when I had to get it done by and I didn't do it. All right, everybody. Thank you for answering my dumb question. Every week here on SciShow Tangents, we get together to try to stump and one-up and amaze each other with facts about our world. And we try to stay on topic, but the name of the show is Tangent, so we're not great at it.

Our panelists here are playing for glory, but you're also playing for Hank Bucks, which I will be awarding as we play. And at the end of the episode, one of you will be crowned the winner. And now, as always, I will introduce this week's topic with a traditional science poem. There are a lot of people who are working very hard, so that each of us can spend less time in a graveyard. They stay up late at night because they want to cure diseases, from the most severe to just the ones that give you little sneezes. And if they just keep working, work better, and work fast, might there be some limit where a barrier's surpassed? Our lifespans do get longer with every passing year, and sometimes

those leaps happen faster as new breakthroughs appear. So what if lifespan increased by one year for every year? That's what people mean when they say the singularity is near. Download our consciousness into computers for all time, create a cryogenic bath that keeps us in our prime, rejuvenate our bodies with techniques we can't foresee, and soon we'll find we're on our way to immortality. That is until the sun explodes or we give up on our endeavor. There isn't much that makes me think that anything's forever. Our topic for the day is immortality. One thing that I know and would like to say up front to all the people listening is that you too will die and nothing lasts forever. So let's find what we value and move forward from there. Sari, what is immortality?

Well, on that cheery note, mortality is what we're all subject to, the fact that we're going to die someday. And immortality is not that. So it is just not dying. Are there ways that this happens? Because I hear about them, jellyfish and stuff. Yeah. So biological immortality is usually defined in terms of senescence, which is this word that means biological aging and is the gradual deterioration of the function of biological organisms over time, whether that's like DNA stability or other genomic instability. This is where telomeres come in. And like after you've copied your DNA

a certain amount of times, these like bits at the end get cut off. But there's also just things like getting worse at transferring nutrients and your cells getting old and holding their liquids and their things less good. You actually do get less good at holding your liquids.

That's a real thing. And so there are organisms out there that have negligible senescence, that hydrozoin that Hank is mentioning is one of them where we can't see the biochemical effects of aging in ways that are recognizable to us. So they have stem cell populations that don't die off, or they can revert back to a less mature form and then grow older again and then revert back and then grow more mature again without losing that biological function. In order to live forever, you also have to not get killed. So like living forever, like biological immortality is the idea that like you could,

but you're probably not going to because something's going to happen. Like the real problem with immortality is that like you don't get the option of natural death anymore. You will die in an accident. is that like you don't get the option of natural death anymore. You will die in an accident. Like if the singularity comes, everyone who dies will die an unnatural death. You'll just get hit by a car eventually.

In my definition of immortality, at least, it's like you can stop the aging, like the natural aging of your cells, but you can still get something like cancer as a disease. So like that as a disease. So like that as a, as a natural cause of death, but like disease that racks your body is different than delaying the effects of aging. I do very want, very much want to delay the effects of aging. Like I don't hold out any hope for immortality, but I would love to be a sprightly 70 year old. It's hard to, to get, to get used used to this idea but i may be a little too old

to to really benefit from the effects of all the anti-aging therapies that are on the horizon but the horizon is still pretty far away you gotta clear the way for the kids to take over eventually that's the thing i worry about the most that's true yeah gotta get some new viewpoints in there thanks for throwing a little bit of social science into it, Sam. Yeah. The word immortality, I guess its root is mort, which all I know is that that means death, but I guess it's named after, like, the god of death whose name is Mort. Oh, I certainly don't know that. There's the Proto-Indo-European root, mer, that means to die or die or like rub away or harm.

I don't know, all kinds of bad things. But what was interesting to me is it's also the root of mortgage. Oh, wow. Which means dead pledge, so-called because the deal dies when the debt is paid or when the payment fails,

presumably because the person is deceased. All right, it is time for our first game of the day. It's a game that I have developed with a little bit of help from Deboki, but I didn't let Deboki know the answers. So this game that we're gonna play is called What Lasts Longer? And we're gonna go round robin

and I'm gonna ask you each, I'm gonna give you a pair of two things and you're gonna tell me which of those things lasts longer. Is everybody ready for the thing? Seems straightforward enough, yeah. All right. We're going to start out

with Deboki. Deboki, you're going to answer me this question. What lasts longer, the average molecule of oxygen 20, the isotope of oxygen that has four extra neutrons, or the average bowel movement?

A human bowel movement? The average human bowel movement important clarification okay i'm gonna guess i'm gonna i i i'm gonna guess the bowel movement deboki most atoms around us will live for as long as the universe but oxygen 20 uh exists for only 12 seconds on average before it decays into other things. And that is less time than it generally takes to poop. I think that you could probably get one out in less than 12 seconds. But on average, it's more like, I think I saw a generalized minimum of 16 seconds. And I was like, who did this?

Yeah, I want to know what the start time and end time is. Yeah. If it's 16 seconds, it's not from when your butt hits the seat. I mean, unless you got to the seat late. All right. We got to keep moving. Sam, this next question is for you. An adult female may fly.

Okay. Or the average YouTube video, which lasts longer? Oh, shoot. I bet there's so many second long youtube or is there a minimum upload i'll just go with the mayfly lasts longer than a youtube video people usually talk often about how mayflies don't last long they're famously short-lived and i sometimes hear that they last they they survive for one day but there is a species of uh adult female mayfly that exists for five minutes after hatching into its adult phase. During that time, they have to mate and lay eggs.

That is half the length of the average YouTube video now. Wow. Which are over 10 minutes long. That is very surprising. Sari, answer me this. What lasts longer, the Titanic or the African pygmy mouse? The Titanic from point of construction to point of from the moment it hit the water to the moment it was beneath the water okay i'm gonna say the mouse lasts longer and you are correct the titanic lasted for 308 days after

it hit the water and the african pygmy mice is a very short-lived mammal. And they live for around two years. Deboki, it's back around to you. A pigeon or a dandelion? Which lasts longer? I feel like dandelions could last a while. I think plants are hardy. I'm going dandelion.

Dandelion, on average, can live for 12 years. A pigeon is actually a very short-lived bird at just six years. Sam, we're back around. A cat, a cat, or a termite? What the hell? This seems like a double trick question. I'm going to go with a cat. No, Sam, no.

The average termite, now an individual termite, lives less time than a cat. But a queen, a termite queen, can live for over 50 years, and we are not sure. What? We think that they might live up to 100 years. Oh, no, that's horrifying. To be by far the longest-lived insect, it's a bit of a mystery,

and other insects that live that long tend to be dormant for a lot of their lives, whereas the termite queen is just doing its business the whole time. So termite queens might outlive people. Sari, a chameleon or a peacock? Which lasts longer? I'm going to say a chameleon,

just because. Now, a lot of these ones that I pitched to you, they're actually quite close. This one is not at all. You are wrong. Chameleons live one year. Peacocks live 20.

Deboki, an ostrich or Harry Potter's parents? Which lasts longer? They were like 30-something, right? Let's go ostrich. You are correct, but you were wrong about how old Lily and James Potter were. They were 21 years old when they were murdered by Voldemort. Ostriches can live up to 75 years. Sam, the Gutenberg Bible or a tuatara, which lasts

longer? Oh God, the Gutenberg Bible. You are correct, Sam. You did it. Tuatara, unlike chameleons, can live over a hundred years. So you think they look like lizards, but they are not closely related. And tuatara, for for some reason live a very long time. The oldest one is 120 years old and he looks very cute still. I saw a picture of him. Whereas the Gutenberg Bible is much older than that. But it's a science podcast. So I'm not even gonna tell you how old.

Sari, the oldest lichen or the oldest coral, which is older? Oh, I'm gonna say the oldest coral just because marine things have figured it out earlier than land things. I hear you on that, but you are wrong. Oh, no. The oldest coral that we have found

is a deep sea coral. It's over 4,000 years old, whereas the oldest lichen we have found is also in a cold climate. So this is a sneaky thing that when it's colder, you can last longer, is over 8,000 years old.

Wow. Took all the adaptations from the ocean creatures and then just went into the cold land. Tavoki, a tortoise or a clam, which is older?

Or which lasts longer? I messed up the game. I'm going to go with a clam a clam is correct there's a clam named ming ming was collected in 2006 off the coast of iceland uh in an ocean dredging experiment where they were doing some science to figure out climate change stuff brought ming up counted the rings because you could do that on clams 506 years old. Oh, wow. Oldest individual animal that we know of is this clam. Did they put it back?

No, it was dead by the time they got to it. But we imagine that there are others like that out there. And does it hurt? Does it hurt a little bit? It does. That's correct. Sam, the oldest shark or the oldest whale? Oh, the oldest shark.

You are correct. The bowhead whale lives over 200 years. That's the oldest whale. The Green the oldest shark. You are correct. The bowhead whale lives over 200 years. That's the oldest whale. The Greenland shark famously lives over 400 years. How does it do that? As far as we can tell, by doing basically nothing ever. I love those guys. And finally, Sari, what lasts longer, a sun-sized star or an earth-sized planet?

Oh, no. A sun- sized star? Yes. I don't know anything about space. You chose a good one for me. An earth-sized planet can last for as long as it wants. As long as it doesn't get eaten by a sun- sized star. But stars have a lifespan,

whereas planets are just rocks. I knew that one. I under- overthought it? I don that one. I under overthought it. I don't know. I panicked. All right. Final score. Sari, did you really only get one right?

I'm really bad at this game. Wow. Sari only got one right. One point. Sam had two. Deboki, all four correct. What the heck? Reigning champ of this one game.

Well, I guess that's why you're in charge of making sure we get stuff right. Next, we're going to take a short break and then it will be time for the fact off. Welcome back, everybody. It's time for the fact off. All three of our panelists have brought a science fact to present to me in an attempt to blow my mind. And after they have presented their facts,

I will judge them and award Hank Bucks in any way I see fit. And to decide who goes first, I have a trivia question. As of the recording of this podcast, the oldest verified living person in the world is Kane Tanaka. How old is she? I'm going to go first, if that's okay. I'm going to guess 110. I'll go 115.

Ooh, big number. Sari? I'm going to go 114. Boxing Sam in a little bit. Yeah. Connie Tanaka is 118 years and 31 days old. Wow. Congratulations.

Yeah. The oldest person on record was 122. Connie Tanaka's coming for that record. Wouldn't it be wild if you were 80 years old and you're like, well, I'm on my way out. And then 30 years later, you're still kicking. So that means that Devoki gets to decide who goes first. I will go first. So in 1956, some scientists wanted to know what would happen if you shot a massive amount of gamma radiation at some canned ground meat.

So they used a dosage that is... I'm sorry I interrupted you with that. I don't think Sam and I can beat that. It's over. Okay. They used a dosage that is 250 times higher than you would need to kill E. coli. So this seemed like a pretty respectable way to kill everything in the meat, except that something survived. A new bacteria, which they named micrococcus radiodurans, though they later changed the name

to dinococcus radiodurans. The big reason why dinococcus should not have been able to survive all of that gamma radiation is because that type of high energy radiation can break the bonds in DNA. And usually, like if you break one strand of DNA, that is bad and you need to fix it. If you break both strands of DNA, it's really, really bad and even harder to fix. And so it usually doesn't take that much damage like that to kill an organism. If you're an E. coli, you can get to like eight to nine of those breaks per like copy of your genome. And at that point, that is like when you will probably die. But if you are a Deinococcus radiodurans, though, it takes about 275 breaks per genome copy to become lethal. So it's able to withstand about 30 times more DNA damage than E. coli. So it turns out that Dynococcus

isn't any better at preventing that damage, but it is much better at surviving it because it's basically like the Wolverine of DNA repair. So while like all of our cells, they have these types of different DNA repair mechanisms, Dynococcus's enzymes and pathways are just like way better at it. It has multiple genome copies, which means it can have more than 1,000 breaks to piece together, depending on like how much damage you've inflicted on it. So it's basically this like semi-dead organism that can only revive itself

by putting together a thousand plus piece puzzle that it also cannot get wrong. And again, there are a lot of DNA repair mechanisms out there, but Deinococcus radiodurans is just like operating at this whole other level. These methods likely evolve to protect the organism if ever gets like dried out or desiccated, which can also damage DNA. But it's also not like DNA is the only thing that gets damaged during desiccation or radiation. There are other molecules in the cell that are going to be damaged too. So it's still not even clear, even though we know that it has these mechanisms in place, it's not clear even like how they can

initiate those mechanisms. So scientists are still studying the microbe to learn more. And of course, because we are humans, that means we've done the only thing more natural to us than shooting tons of gamma radiation at CanV. We've shot Deinococcus into space where it spent a year outside the ISS exposed to the sun and it has also survived that. I mean, panspermia is totally a thing. We're not from Earth. We came from somewhere else. Okay. I have a

question. Did they leave the meat out for a while or does all canned meat have a bunch of Deinococcus radiodurans in it? I do not know. There were a lot of papers that are talking about this papers but the original research paper itself the methodology i was having a hard time hunting down so i don't know how long this meat is like lying around but

i think we're probably okay i don't know i hope well yeah i mean my guess is that dinococcus radiodurans probably doesn't do that much damage to a person i wouldn't want to eat e coli but if you're gonna like if it's like way too hard to kill every single bacteria, don't kill the ones that aren't going to hurt me. I'm eating some right now. All right, Sarah, you are second in guessing the age of Kanetanaka. What is your fact? So like the Hydrozoan species we briefly mentioned in the definition section,

one of the weirdest natural phenomena to me is reverse development, where organisms are like, nope, conditions are not favorable right now, so I'm going to go back to being baby and grow up later. And I recently learned about- If only the graduating class of 2020 could do that. I hadn't heard of this before. I recently learned of a dermestid beetle named Trogoderma glabrum that is in the same family as the ones used to clean bones for taxidermy or for museums, but this beetle feeds on grains instead of scavenging flesh. And normally this beetle's development works, the babies eat and molt into larger larvae until they eventually pupate and

then become an adult. But if you deprive the larvae of food and water before they pupate, they will molt the other way, like a Russian nesting doll, and become smaller larvae instead, kept in perpetual youth. So even though time is passing, they're physiologically getting younger and reversing the genetic steps towards maturity. And this can prolong their lifespan. So normally, these beetles live from egg to death for about eight weeks, but in a paper from 1972, two scientists kept larvae alive

for more than two years through 20 to 36-ish week cycles of food deprivation and regrowth. And it could probably work for longer, but they just got bored, question mark, and wanted to see if the beetle larvae would pupate into adults, which they did. So this staying baby process isn't perfect immortality because they still showed some cellular signs of aging. For example, it took the larvae gradually longer to redevelop into their original size from nine days in the first de-age, re-age cycle to 28 days in the fourth cycle. And their fat cells had DNA composition similar to adults instead of babies, which the authors speculated could have caused those longer re-aging timelines. But as far as I can tell, this 1970s paper was the only big

experiment on these beetles. But more people could be studying this. And maybe people aren't interested because humans don't molt and pupate. That's my guess. But I think someone should be studying these beetles. There is definitely an economics comparison here. If you almost let people become adults and then you throw them an economic crisis, they will revert. That's been the last 30 years of life here on Earth. That explains a lot of stuff about me.

Oh, God. No, I mean, none of us are grown-ups sam what it no don't worry all right very weird very good sam can you top it probably not but i'll try so in some respects living forever seems nice but let's say you're a vampire and then think it out to its logical conclusion so assuming that you weren't vampire hunted, would you live through the destruction of the earth or the sun burning out or the heat death of the universe? Eventually, would you like feel all your atoms lose coherence and drift apart? Probably, and then you'd be dead. But then what about the particles

that those atoms are made of? Are they the one thing in the universe that's truly immortal or would even they eventually die too? Well, that question, the part about the particles dying and not the vampire speculation is what an international team of scientists set out to answer in 2015 i love it great great frame sam we one thing that we never think about is how do we make this understandable to sam shultz it's the only thing I ever think about. So now I'm going to talk

about particle physics and I'll probably be wrong, but I'm going to try. An electron is the least massive charge-carrying particle. True or false? Yeah. True.

Cool. And we've never observed an electron decaying. And in fact, if I'm understanding my brief skim of the Wikipedia article for the standard model of particle physics correctly, a I'm understanding my brief skim of the Wikipedia article for the

standard model of particle physics correctly, a lot of the way that we understand how the universe is put together depends on the fact that electrons don't decay. For one thing, they'd have to lose their charge, which would, I think, disprove the law of conservation of energy, which seems bad. But there are non-charge carrying particles out there that are less massive, like photons and neutrinos. And I guess it's not entirely out of the question that an electron could break the laws of physics as we know them, lose its charge, and split into these smaller particles, even if we've never seen it. ton tank of super pure petroleum based, quote, organic liquid shielded from any outside radiation and also under a mountain to further shield it from radiation. It's lined with thousands of special cameras that can detect some subatomic particles. And I think it's basically like an aquarium, but it's full of a known quantity of particles

instead of fish. So what they were looking for is there's a hypothetical idea of what it would look like if an electron decayed. And part of that idea is that the electron would let out a flash of light that would be detectable to the equipment in the detector. So they set it to detect this flash of light. And after 408 days, they didn't see any of those flashes. So there are 10 to the 23rd electrons in the tank, which I guess is a super huge number, and none of them decayed. So the researchers were able to math out that an electron's lifespan is probably more than 66,000 yada years, which is 6.6 times 10 to the 28th years, which is five quintillion times longer than the universe has been around. And that's like the lower limit. Yeah. A quintillion times longer than the universe has been around. And that's like the, that's the lower limit.

Yeah. A quintillion is 18 zeros. And since the detector isn't perfect, it's probably even longer than that. That's just as far back as we can math it out right now. So the law of conservation of energy is safe for now, and we can rest easy slash be terrified to know that the basic building blocks of our reality will still be floating around quintillions of years after we're gone even ones that currently make up you me and vampires if we have electrons

in us which i'm only like 90 sure we do we have electrons yeah i am 100 sure we have okay cool phew oh god um Sam that was that was really well done man thank you you got all that right that was great and I love you took

immortality to it's like it's at furthest possible extent yeah I'm not gonna be around no maybe the earth isn't gonna be around forever but our electrons will be

and uh it really seems like maybe forever though who knows? Maybe there is a state at which eventually the universe kind of collapses into a bunch of black holes

that become future Big Bangs. Not my problem, so. Well done. Oh gosh, and now I have to choose between the three of you. I think I'm gonna give Sam, I think I'm gonna give you four points because i like you like the vampire thing was very good you like you like drilled down and got out like got a bunch of particle physics which isn't easy and i appreciate it and understood i understood what was going on

which i don't always when we get into that i'm gonna give deboki three points because that was my second favorite thing. And I forgot what it was already. We were ionizing cans of meat. Oh, yeah. You ionized a can of meat for me, which I always appreciate. And Sarah's coming out with two because it was also very good. And that means that the winner of today's episode is Deboki Chakravarti with seven points, beating out Sam by just one solitary stinker.

And it also means that it's time to ask the science couch. We've got some listener questions for our couch of finely honed scientific minds. This question is from at RebeccaRebek4. What is the science slash reality behind cryonics? Can you really freeze something and bring it back to life? I know that you can freeze a nematode and bring it back to life, but I don't know if it gets much bigger than a nematode. Something bigger than a nematode has been frozen and then thawed, but not a whole organism.

Rabbit kidneys, for some reason, in the research that I was doing, rabbit kidneys for some reason in the research that I was doing are like the prime experimental material for preserving an organ and then thawing and trying to transplant it back into an organism. And so in 2009, a group of researchers used quick freezing techniques and I think with chemical cryopreservants, which basically act like antifreeze. So when it freezes, the antifreeze solution doesn't crystallize the way that blood would in the kidney, which would be bad because then the ice crystals would form and that would damage cells. So they used this antifreeze concoction to preserve and then thaw a rabbit kidney. And then they put the kidney back into a rabbit and it worked for 48 days. And at that point they were like, looks good. And then they euthanized the rabbit so they could study it. So I don't know if there've been any experiments since then that have lasted longer, but it seems like rabbit kidney transplantation is the most

promising field before, I I guess in all of cryogenics in my opinion. I also briefly researched a company that will freeze your brain and they say that eventually they'll figure out how to unfreeze it. They just don't know. We promise. A lot of that I think in terms of whether or not there's any science

behind cryonics. There are companies that will do the freezing and whatnot but the idea that they can freeze you just fine. The idea that they're going to be able to revive you is really the crux of the issue. And that's going to be pretty, pretty tough to do. But there are cases like with surgeries where people will like the surgeons will actually cool a body down and have it go to like really, really, really cold temperatures so that there's basically no pulse, no blood pressure, like no no brain activity, or at least really minimal. And that's to make the surgery easier.

But even then, that is in a very controlled setting, and it is still really difficult. It is still pretty risky, I think. I don't know if it's gotten safer. I think the closest we can say to being able to thaw out a human is probably with like frozen embryos at fertility clinics, which is still remarkable, but it's, it's still going to be a bit a ways from being able to, to revive a frozen full grown human being.

Yeah. I mean, I mean, it does make me think that there's like a version of it. That's just torpor where it's like, you're not like frozen with like ice with ice crystals, but let's put this person into a state where they could maybe go to Mars and not have to be awake the whole time. Or if you're very sick, you put somebody to sleep until they get to a place where a person gets

to them who can take care of them or something like that. I think something like what you're describing is also a key part of cryonics that we don't talk about as much because usually people talk about like freezing their brain after they die, whether of an illness or of old age. And then that adds an additional problem beyond taking your brain back to life. You have to like that you've died. Yeah. You have to fix what, what killed you also it's like if you put yourself into stasis like if i put myself my 26 year old body into stasis then when i like unstacest then at least my cells wouldn't have aged and i can like resume living

my life but if you're an old person and you die and then you freeze your brain then it's like if you even if you like rejuvenate your body you're still old you still like if you died of natural causes or if you had cancer in the brain then you still have that illness that scientists have to work on and cure well also if you've if you've died your body is starting to decay like and so there's an ethical concern here. I'm not going to freeze you if you're not dead, but if you are dead, you have already started the process

of actually returning to the soil. But there's also these things with cryonics that are potential actually useful therapies when it comes to giving rabbits new kidneys or being able to do surgery on people in situations where otherwise there would be just too much blood. All right. If you want to ask the science couch your question,

you can follow us on Twitter at SciShow Tangents, where we'll tweet out the topics for upcoming episodes every week. Thank you to at Mama Paul Bear at CrystalR99 and everybody else who tweeted us your questions for this episode. Deboki, what are you working on these days? You got anything you want to plug? Watch Journey to the Microcosmos. It's a pretty good show. And if you like Deboki, there's also tons of episodes of Tangents that Deboki's been a guest on.

If you like this show and you want to help us out, it's easy to do that. You can leave us a review wherever you listen. That's helpful and helps us know what you like about the show. Second, you can tweet out your favorite moment from the episode. And finally, if you want to show your love

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and produced by Caitlin Hoffmeister and Sam Schultz, who edits a lot of these episodes, along with Hiroko Matsushima. Our social media organizer is Paolo Garcia Prieto. Our editorial assistant is Deboki Chakrabarty. Our sound design is by Joseph Tuna Medish, and we couldn't make any of this without our patrons on Patreon. Thank you! And remember, the mind is not a vessel

to be filled, but a fire to be lighted. But one more thing. One way to immortalize poop is to let it fossilize into what's called a coprolite, a dried out piece of poo. The oldest human coprolite was found in Oregon's Paisley Caves, and thanks to radiocarbon dating, it's estimated to be about 14,000 years old. I just love that there are some people who are like, they look down and they're in a cave and they're like, that's not a rock. How would you ever know that in a million years? I don't know.

I think I'm assuming it's one of those things where once you know, you see it everywhere. Oh, yeah. All you see is rocks and poop. Poop and not poop, probably. It's a binary filter on the world.