SciShow Tangents - Holes

Episode Date: April 28, 2020

Humans have been digging deep holes for fun and profit since time began, and some animals have been doing it for way longer than that! And all of those holes can't hold a candle to some of the natural holes the Earth's got going on. And those are nothing compared to space, which some (Sam) would argue is the biggest hole of all!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: Stefan: @itsmestefanchin Ceri: @ceriley Sam: @slamschultz Hank: @hankgreenIf you want to learn more about any of our main topics, check out these links![Truth or Fail]Termite mounds: https://www.cell.com/current-biology/fulltext/S0960-9822(18)31287-9?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982218312879%3Fshowall%3DtrueBand of holes: https://www.sciencealert.com/is-this-mile-long-strip-of-holes-an-ancient-inca-tax-systemMolecular drills: https://pubs.acs.org/doi/10.1021/acsami.9b22595#Roman skin cream: http://cenblog.org/artful-science/2013/01/14/ancient-roman-cosmetics-skin-cream-from-the-2nd-century-a-d/[Fact Off]Ant colony fallen through holePictures in this paper: https://jhr.pensoft.net/articles.php?id=9096&display_type=element&element_type=4&element_id=43&element_name=https://link.springer.com/article/10.1007/s000400050022https://arstechnica.com/science/2016/09/bizarre-ant-colony-discovered-in-an-abandoned-polish-nuclear-weapons-bunker/https://www.popsci.com/story/science/ant-colony-escape/https://jhr.pensoft.net/article/38972/Star-nosed mole nose holesThe video!https://www.youtube.com/watch?v=UMz0Q7VbT9whttps://news.vanderbilt.edu/2006/12/20/scientist-discovers-some-mammals-can-smell-objects-under-water-58788/https://www.nytimes.com/2006/12/26/science/26bubble.htmlhttps://www.newscientist.com/article/dn10834-star-nosed-mole-can-sniff-underwater-videos-reveal/https://www.sciencedaily.com/releases/2017/11/171120090051.htmhttps://www.sciencedaily.com/releases/2017/04/170424084028.htm[Ask the Science Couch]Sinkholes / blue holeshttps://www.whoi.edu/oceanus/feature/blue-holes-and-hurricanes/http://geology.wlu.edu/intro3d/sinkhole/sinkhole.htmlhttps://www.usgs.gov/special-topic/water-science-school/science/sinkholes?qt-science_center_objects=0#qt-science_center_objectshttps://www.smithsonianmag.com/smart-news/explore-worlds-deepest-blue-holes-180959977/Flooded pit caveshttps://www.theguardian.com/world/2016/sep/30/worlds-deepest-underwater-cave-found-czech-republic-hranice-abysshttps://www.nationalgeographic.com/adventure/destinations/europe/czech-republic/deepest-underwater-cave-discovered/Mariana trenchhttps://www.nationalgeographic.org/activity/mariana-trench-deepest-place-earth/Kola Superdeep Boreholehttps://www.smithsonianmag.com/smithsonian-institution/ask-smithsonian-whats-deepest-hole-ever-dug-180954349/[Butt One More Thing]Scorpion anushttps://www.sciencemag.org/news/2015/01/when-attacked-some-scorpions-discard-their-stinger-and-their-anus

Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen. This week, as always, I'm joined by my colleague stefan chin i've been upgraded to a colleague from a friend yeah stefan what is your tagline and my axe that was a little too high pitched but we'll go sam schultz is also here joining us. What's your tagline? I don't know. What's on my desk?

Three batteries. Sari Riley is here as well. What's your tagline? Purple gumdrops. My name is Hank Green and my tagline is relentless. Ugh! Every week here on Tangents,

we get together to try to one-up a maze and delight each other with science facts. We're playing for glory, but we're also keeping score and awarding Sam bucks from week to week. Right now, Sam and I are losing together. We do everything we can to stay on topic, but judging by previous conversations,

we won't be great at that. So if the rest of the team deems your tangent unworthy, we will force you to give up one of your sandbox. So tangent with care. Now, as always, we introduce this week's topic with the traditional science poem this week from me. White hole, black hole, punch hole, plot hole, wormhole, porthole, manhole, foxhole. Those are all things and that's no big deal, but they're all named for something that is far less real. A bee without a sting, we call that stingless. But what do we call

a thing that's thingless? Defined, I guess, by its emptiness. Maybe they are novels by Lewis Sacker, maybe dug out by a John Deere tractor, surrounded on every side but above, or maybe they're fronted by Courtney Love. Today I don't envy Sari her role

because how, oh how, do you define a hole? Sari, what's a hole? Well, it's a hollow place in something that is otherwise solid. I think we can agree on that. What about a whirlpool? Would that be

a hole in a liquid? Oh. No. I think it's a hole. It seems like a hole. You think a whirlpool is a hole? It seems like a hole. If it's a hollow.

And you can go down it. Well, okay. Solid or liquid. But can holes be in gases? Yeah, you could probably make a hole in a gas. Is a tornado a hole in the middle?

I don't know. Or a hurricane? There's a hole in the middle of I don't know. Or a hurricane? There's a hole in the middle of one of those. Is space a hole? Or are we a hole of stuff in the nothingness of space? I was wondering that same thing in the shower this morning. So a black hole is more stuff than the surrounding. Right?

That's weird. Well, that's the thing. A black hole isn't actually a hole. Oh, my God. I don't know what actually a hole means. Scientists decided to call it a hole, so it's a hole. You can fall into a black hole, so I think it's a hole. I think it's anything

you can fall into. I can fall into lots of things that aren't holes. Like what? Like a cavern. Is a cavern a hole? It's too big. Yes. Yeah. A cavern's a hole. A canyon, yeah. A canyon's a hole. Is a Grand Canyon a hole? It's too big. Yeah. A cavern's a hole. A canyon, yeah. A canyon's a hole. Is a Grand Canyon a hole? The Grand Canyon is not a hole. Yes, it's a huge freaking hole.

I think it might be a really big hole. I think you guys are just scared because I so easily define what a hole is. Is the entire ocean a hole? Yeah, it is. Nothing's lower than the ocean besides more ocean below it but you can't fall in someone's ear if i was small enough i could easily oh yeah the ear is a hole if you're small enough you could fall into all kinds of things that aren't holes yeah well holes are relative to your size also sometimes Sometimes you fall into a hole. Sometimes you fall through a hole. Is it a hole if it has one opening and two? I thought about this when I

was writing my poem. It has to have at least one opening or does it? Can it just be a vacant space inside of something? Oh my gosh. If I close my mouth, is that a hole? It's a cavity. Oh yeah. It's a cavity. Yeah. And then I open it, then it's a hole. Well, I think we've got it. I looked up the etymology of hole, and I was somewhat surprised. It is one of those words that goes back to a proto-Indo-European root that is really common. It comes from, weirdly enough, like a covered area area and it is the same root as house in that sense hole and cavity sound like they're the same thing oh yeah no i mean in the if it's

sort of like we use etymology in the same way we use taxonomy where like you are whatever you are related to then hole is everything to cover or conceal or save And it's got like ceiling is the same root and helmet and like a haul, a hollow, a holster, the hull of a nut, all from the same stuff. But also the word apocalypse comes from the same root. No. And so does kleptomania. What? Well, it's an old word.

It's gone through a lot of changes and a lot of people feeling different ways about how we should pronounce things. Putting their own spin on things. Yeah. I'm really glad we've had so many more words invented since then. It would be so confusing if I had to walk around being like, well, I'm in my hole and you're in your hole. And I'm headed to the hole right now, but I have to go in my hole first. And now it's time for Truth or Fail. One of our panelists has brought three science facts

for our education and enjoyment, but only one of those facts is real. The rest of us have to try and figure out either by deduction or wild guess, which is the true fact. If we do, we get a sandbuck. If not, the presenter gets the sandbuck. This week, that is Stefan. Stefan, Jen, what are your threebuck. If not, the presenter gets the sandbuck this week.

That is Stefan. Stefan, Jen, what are your three facts? I've titled this truth or fail, three old holes. Fact number one. In Peru, there are stretches of road covered in shallow holes along part of what used to be the Incan highway. These sections of road are steep enough that they would have been hard to traverse unassisted, so they think that these so-called bands of holes were used in conjunction with an ancient version of studded wheels to help carts gain enough traction to travel on these roads. And they were also big enough to provide footholds for people who were traveling on foot. Number two, archaeologists found a full can of skin cream hidden in the drain of an ancient Roman temple. It dates back to the second century CE, and the cream has antimicrobial properties.

It contains a substance whose molecules act like molecular drills, killing microbes by boring holes through their cell walls. Researchers are now looking into using these to develop treatments that work against antibiotic-resistant bacteria. And then number three, researchers found a network of 200 million termite mounds in Brazil. The mounds are regularly spaced apart and connected to each other through a vast network of underground tunnels. The whole array covers an area the size of Great Britain,

and samples revealed that some of the mounds are close to 4,000 years old. And the amount of soil used to build the mounds is equivalent to several thousand pyramids of Giza and represents one of the largest insect structures ever built. Wow, and they're all connected to each other? Mm-hmm. Okay, so we've got our three old holes. You've got roads covered in bands of holes

that were maybe combined with ancient studded tires that allowed Incans to transport goods up steep roads. Or you've got a Roman skin cream that was found in a hole, in an old hole, and it has molecular drills that kill some bacteria. Or number three, a giant array of 200 million termite mounds. Is that right? 200 million termite mounds. Is that right? 200 million termite mounds? Oh my goodness. In Brazil, connected through underground tunnels, collectively one of the largest insect structures we know of and over 4,000 years old. I feel like, and this has gotten me into trouble before, I would have heard of the termites.

That seems like something I would know. I know. It's weird. It's giant. It's very big. Maybe you heard of it termites. That seems like something I would know. I know. It's weird. It's giant. It's very big. Maybe you heard of it and forgot it. Do you forget things ever? Oh, very often.

Okay. But I usually have some faint tickle of a memory. Right, right. It's not like I could call it back, but if somebody said there is a termite mound network the size of Great Britain, I'd be like, hey, think, I think that's in there. That's in there. So where did they find this hand cream? Was it a hand cream? Face cream? It was a skin

cream. Just all skin. Skin cream. Any skin you can think of. Whichever skin. And it's good because we do need hand sanitizer these days. They found it in a drain in an ancient Roman temple. So is it like someone's secret stash of it? I think so, yeah. Or were they like washing it out?

Hiding it away. How long have we been using skin cream for? Do we know that? I imagine since we discovered plants. We were slathering things on our skin. Absolutely. It's so dry sometimes of the year. I will be so itchy that I will think,

people lived before now. Like, what did they do with their skin? Were they just always in pain? But they're just oiled up all the time, right? I guess, yeah. You just rub yourself with some tallow. Roads covered in bands of holes. This seems like totally something the Incans would have done and would have needed to do because all of their cities were like the famous city.

What is it called? Machu Picchu. Machu Picchu. They built this beautiful big city at the top of a mountain, which is like the worst, hardest place to build a big, beautiful city. So they would have needed some way to get rocks up to the top of this thing. Sari and I are quietly thinking that one of them sounds like a load, I think. Mm-hmm. Ooh.

What the heck? Okay. I feel good about the giant array of 200 million termite mounds the size of Great Britain. I think probably maybe I have heard about it and I forgot about it, but it totally seems like it might be a thing. I'm going to go with that. I'm gonna go with the wheels and the little nubby wheels, because

why not? I think I'm also gonna go with nubby wheels. I'd love to hear more about these nubby wheels. If I'm wrong, at least I'll get to know more about the nubby wheels. So Hank was correct. Hey! So these are visible on google earth it's this gigantic area covered in these evenly spaced termite mounds until recently they were covered

by the forests in that area and but they have and i'm sure like the locals knew about them but i guess they recently cleared some of the land for like pasturing. And so now outsiders were like, hey, what's going on over here? I didn't really know how termites work, but I guess the mounds are like, it's all the dirt that they're excavating to make their tunnels. They estimate about 200 million mounds total, which the total amount of dirt to form all of those, because they're like meters tall, the total amount of dirt to make all of those would be about 4,000 pyramids of Giza. Wow. Good boys or girls. I'm not sure. Good work. That's a lot of effort. And of course, now we can see these termite mounds because they've cleared the wood away. But I have some bad news, re-termites and wood. Which is that they kind of might need that.

The road holes. Apparently, the Incans did not have wheeled vehicles at all. So these holes were on the ground, but they were next to the road. And it was like a mile long strip of these holes and it doesn't seem like they just dug holes they were like constructed from material that they brought in from elsewhere but nearby was a storage house called a kolka and they knew that in the inkan empire they had these kolka buildings spread out along the road or the highways and they would collect like supply like food and textiles and whatever as sort of attacks from people who live

nearby and then as the armies were like passing by or or whatever they could grab food from this or if there was like a famine then they could redistribute some of the food to the the people who were in need and so they thought that they think that these holes were just used to like measure the amount of food that you were like giving as your tax. So you had to like fill this hole with apples and then you're good to go or whatever. We can bring that system back to exchange goods and services outside of our houses. Right, right. Fill this hole with toilet paper.

Fill this one with hand sanitizer. Mm-hmm. And I'll trade you one hole of canned mandarin oranges. That's a valuable hole. And then the skin cream was a combination of two things. So we did find an ancient Roman skin cream tucked away in a drain somewhere, but it wasn't antimicrobial or anything, but they like reverse engineered the recipe so they could make a fresh batch

and like try it out. And the researcher said, this cream had a pleasant texture when rubbed into the skin. Although it was greasy at first, it was quickly overtaken by the smooth powdery texture. That sounds nice.

They had a good skin cream, it sounds like. The drill thing is a more modern invention. I guess we have artificial molecular drills. I don't really know how it works, but if you activate them with light, parts of the molecule start spinning at three million times a second, and they can bore holes through cells and kill them.

In this paper, they were only like, they like put these into worms and plankton and they killed the organism. It wasn't like fighting bacteria, just like killed the worm, killed the plankton. And they put it on mice as a cream and it just gave the mice skin lesions. So like, so far they've just demonstrated

that like these are drilling into cells and killing them. So this is bad. We've made a bad thing. Well, they seem confident that you can attach peptides or whatever to the molecules and have it target specific things. But I don't think they're at that point yet. What was the one you thought was a load? That one, the hand cream. Yes, I also thought that one was too many things packed into one.

The hand cream seemed totally likely. What didn't seem likely was that it was antimicrobial. And if it was, that it would be potentially useful for drug-resistant bacteria, which are like, they're baddies. You're not going to just find some hand cream somewhere. Next up, we're going to take a short break, then it'll be time for the Fact Off. Welcome back, everybody. Sam Buck totals. Sari has nothing.

Sam has nothing. And Hank and Stefan are tied with two. Gimme. But we can't make any more points, so I guess we're not going to win, Stefan. We're at best going to tie. Now it is time for the fact-off. Two panelists have brought science facts

to present to the others in an attempt to blow our minds. We each have a Sam Buck to award to the fact that we like the most. And to decide who is going to go first, I have a trivia question for you both. A blue hole is a large marine cavern or sinkhole. The deepest blue hole in the world is in the South China Sea, and it is named the Dragon Hole. How deep is it? I think I unintentionally know this because of the answer to the Ask the Science Couch question. Oh, you like look this up?

Sam, do you want to go first or second? No, I want to go second, please. Sneaky. My guess is 300 meters, I think. Wow. My guess is 301 meters. Perfect. Oh, I think. Wow. My guess is 301 meters. Perfect. Oh my god!

The hole is 300.89 meters. Sarah, are you checking your blanket fort for spiders? Does it stay up all the time? I'm worried about it. It does stay up all the time. I found a spider today, which is why I was a couple minutes late, because it was in my headphones. Oh, no.

Worst place. Okay. Well, be careful. Thanks. That's all. And also, you go first, please. So, European redwood ants look and act like pretty average ants. They form colonies with a queen and workers and a caste system and forage for food and defend themselves from rival colonies, like classic ant things. But there is one colony of about a million of

these ants that completely defies this model. And it's the only one in the world like this that we know of. In Temple Wo, Poland, there is an abandoned underground nuclear weapons bunker that was built by the Soviet military in the Cold War. And so trees are growing over top of this bunker as camouflage, and there's soil and a whole forest ecosystem that's going, including a massive colony of these wood ants. And the thing is, there's a ventilation pipe that rusted away and left a gaping hole into the bunker so worker ants regularly fall through the hole and can't escape back out.

And so all these fallen worker ants have basically banded together and formed Ant City down there. But it's very, very weird because it's freezing cold, 10 degrees Celsius to below zero. There's barely any food besides maybe some stuff that grows on bat poop, but that's not nearly enough. So researchers aren't sure where they're getting any nutrition. And when researchers inspected the mound in July 2015, there were no queens, no males, and no signs of any sort of larva. So it's just like a million female workers that can't reproduce and are working to maintain their very sad nest as best as possible. I don't understand. They shuffled dirt around and they fixed whatever

the researchers broke when they went down there. But tidying up is mostly making sure that entrances are clear and moving dead bodies out of the way. And so there are centimeters thick piles of dead ants down there. They estimated about two million dead ones and one million alive ones. What are they eating? Do they eat freshly dead ants? Is that a thing ants do? There are small mites and things that might be eating the dead ants that the ants might be eating, but nothing that the researchers found

down there seemed like a significant enough food source. We don't know if they just keep living as long as they can without eating and then die eventually, but the only way this colony survives is from ants falling from that hole above. So like the magic ant hole gives them more people and they will just keep on living in this extreme environment

because they don't know any other way to be. Can ants climb walls? They can climb walls and there are pictures of them climbing partway up the walls, but I think the way the bunker is constructed and the way this ventilation shaft has rested, it's not like a clear, easy thing to crawl up. I think it's like flat concrete walls that they can climb about halfway up, and then they'd have to get onto the ceiling, and then they'd have to climb over a ridge and up. Somebody needs to help them.

Those researchers should have left them a stick or something. I mean, Sari, I'm looking at a picture, and it looks like the have left them a stick or something. I mean, Sari, I'm looking at a picture and it looks like the researchers left them a stick. The wooden boardwalk led the trapped insects to safety. When researchers returned in 2017, they found that most of the ants had taken advantage of the new escape route.

Sari, you didn't have the whole story. Clearly not. I thought I had the whole story by reading their paper, but I didn't get their update. They violated the prime directive. You ruined this most special of ant holes. I can't believe I missed

this part of the story as I was researching it. I thought I really got all the details, but this is an important one. That they're not there. That's so wild to me they just like integrated back to society and then they got they went back to the nest where no one recognizes them and they were like so I was stuck in this hole just like that

way and there's a stick look if there's you could we can go back down we can get it's no big deal now let's go back down and see the million dead ants that are in this nuclear bunker hole. All right. Sam, what do you got for us? Swimming is a great and fun activity.

Everybody likes to splash around in a pool or a lake on a hot day. But humans have a lot of holes all over them and any water or too much water in any of those holes can be really unpleasant and none more so than the nose hole. So considering that it really sucks to get a bunch of water up your nose and probably it sucks to lots of other mammals besides just people, you might think that smelling underwater is not something that's possible. And up until pretty recently, researchers would agree with you. In fact, even most whales and dolphins don't have

olfactory bulbs at all. They've just evolved away. And those that do have them only smell when they're above water. So underwater mammal sniffing was basically written off as impossible until 2006 when Dr. Kenneth Catania, a biologist who studied star-nosed moles, finally got to the bottom of a question that had been bothering him since the 80s. Star-nosed moles finally got to the bottom of a question that had been bothering him since the 80s. Star-nosed moles are little moles that live in marshy areas and swamps and ponds and stuff in northeastern North America. And they have really gross, disturbing tentacle noses, like noses with stars basically growing off either side of them. And they spend a lot of their time swimming around in ponds, eating aquatic

worms and bugs. So Dr. Catania was looking at these moles in a zoo, I think, and noticed that when they were swimming, they were losing lots of air bubbles out their noses, like way more than they should be for a creature that's trying to hold its breath for a long time. So he just looked at them, I guess, in the 80s. And then it took him until the 2000s when he started studying them with high-speed cameras to see what was happening to their bubble situation while they were swimming. And he found that the moles were only blowing bubbles at certain times, like when they were near a potential food source.

And he also noticed that the rate of bubble blowing was about the same as the rate of inhalations that the mole would take while they were sniffing when they weren't underwater. So then with the high-speed cameras, he saw that a lot of the bubbles would escape, but a good number of them would get caught in their nose tentacles and then get snorted back up into the mole's nose. And there's a really funny video of it that I will put in the notes as well. So from this evidence, he figured out that the moles were using bubbles to capture scent molecules in the water around them. And they would go inside the bubble where the air was,

and then they'd sniff them back up. And so that basically let them smell things while they were underwater. So he set up little tests for them where he gave them two tunnels to pick from, and one had a worm that had like crawled down it and one didn't and they could basically like sniff along the tunnel underwater to get to the one with the worm in it and they were right 85 percent of the time and then he set up these like mesh things that would pop the bubbles when they stuck out their nose so they couldn't sniff anymore and after that they were only right 50 percent of the time. So basically, like, they were sniffing their way over there.

And since then, it's been found that a lot of semi-aquatic mammals, like rats and shrews, do the same thing. And researchers are working to turn this technology into electronic noses that you can put underwater that can sniff out chemicals without actually exposing any of the electronics to water because that's a bad thing to do. So like the stink gets into the air and like the flash of time when that bubble

like gets spat out of this mole's nose and then sucked back in, some, you know, volatile compounds or scent compounds of some kind get into the air and they suck it back in. Is this the reason that these moles have such bad, bad faces? I couldn't understand why rats and other things could do it and don't have bad faces. But the researchers who are working on the electronic noses found that when they put a star shaped thing around the stuff that was shooting bubbles out similar to their noses, that the bubbles wouldn't be able to rise up as fast and they would get stuck

on stuff and then they could suck them back in. I mean, I'm sure like probably other animals can do it, just not as well. Right. And you know, that's how, that's how the behavior evolved.

Now, Sam, I love this and I have one question for you. Yeah. What are the holes? The nose holes. Nose holes. And they use the mesh to pop the bubbles. Yeah, there's holes in mesh too. That's also holes. Nose holes. And they used a mesh to pop the bubbles.

Yeah, there's holes in mesh too. That's also holes. And they went down holes that the worms were in. Yeah, and the bubbles coming out of the nose are holes in water. Yes. There's so many holes. There's really holes everywhere you look. I find this tenuous.

Nostrils are undeniably holes. You can fall into them. If you're small enough. All right, Stephan, are you ready to vote with me? I thought I was going to be ready,

but now there were so many holes in Sam's. Sari's had holes that you don't even know about. Yeah, Sari's kind of isn't a hole anymore, though, because the ants can get out of it.

No, it's still a hole. It's still a hole. They fall in still. They just can get out. Yeah. Maybe so. And my story had hole still a hole they fall in still they just can get out yeah maybe so and my story had a quite literal hole

because I didn't know the second half of it oh that was like a plot twist as well alright I'll count down three two

one Sam oh oh oh no why would you give me the thought you were so mean to me

your fact was really good. I never thought about smelling underwater. That was really good. I know, and I've always wanted to know why those moles have bad faces. Sarah, your fact, of course, was also very good, and I'm very glad to know about the bunker ants who are now free. I guess I'll stick around and do the science couch and the butt fact. Well, it is time.

For no points. It is now time for Ask the Science Couch. We've got a listener question for our couch slash blanket fort and chair of finely honed scientific minds. This is from atwatchwild185. What is the deepest naturally occurring hole that we know of and how does it compare to man-made holes? Now, Sari, I know you're going to have an actual answer to this, but from what I understand, apparently the entire ocean is a hole. So it's that one. I was looking at holes slightly smaller than the entire ocean. So forgive me for that.

I didn't talk to Sam and consult him on the definition of a hole before researching this question. I mostly looked into sinkholes because the dragon hole is a type of sinkhole. And that's where the rock below the surface of the earth is some sort of limestone or carbonate rock or salt beds or anything that can be dissolved by groundwater. And how a lot of these ocean sinkholes formed, the Dragon Hole is like kind of a mystery, but many ocean sinkholes formed before the oceans covered that part of it. Just like a lot of sinkholes on land, something washed away the support structures underneath,

away the support structures underneath. And then some event happened, whether it was seismic activity or just like there wasn't enough support, physical support beneath it that the hole caved in. And now in the ocean, there are many of these blue holes, which are like very, fairly shallow ocean. And then all of a sudden a like 200 to 300 meter drop. And the dragon's hole is the deepest one, the deepest blue hole that we found and the deepest limestone cave that was measured. And it seems like it was formed sort of like a sinkhole. It's called the Hranice Abyss in the Czech Republic. And it is 404 meters or 1,325 feet at least deep. So I think it was a limestone sinkhole that

is now filled with water so they can dive down into it. And that's about as far as they've dived. But they said that when they measured it, the robot that helped with this effort didn't seem to have hit the bottom of the abyss, so it could be longer than that. Did the robot survive? I think so. I don't know. The story was mostly about the human diver, cave dieter, who led the expedition, less so about his robot sidekick.

You just called him the human dieter. So did he die? Oh, no, he did not die. That seems like probably he did. No. That's great news. I guess if we're considering the ocean, the deepest part of the ocean is the Mariana Trench and the Challenger Deep, which I found a couple different statistics, but the United States Center for Coastal and Ocean Mapping in 2010 measured the depth of the Challenger Deep at 10,994 meters or 36,070 feet deep.

But that is still less deep than the deepest man-made hole, which is the Kola Super Deep Borehole. We made a SciShow video about it way back before maybe everyone but Stefan was working here. And that is nine inches in diameter, but 40,230 feet and 12,262 meters. And so it's the deepest hole on earth. And it took almost 20 years to reach that depth. And I think what stopped them is it got unexpectedly or hotter than they expected. Yes.

Towards the bottom of the drilling. So their materials weren't equipped to continue drilling down. And my favorite thing about the Colasuperdeep borehole is that you can still go out there and look at it. And it just is like a tiny little round cap. You might think it's like a post that was sunk into the ground to build something on top of. But no, it is the deepest hole in the world. And it just looks completely unassuming. Yeah, you can't even look into it. You cannot look into it.

They apparently didn't want anybody thinking maybe that they should look into it. It's good to just try and dig a really deep hole sometimes. You never know what you're gonna find. And like the Cola hole is definitely a hole, right? It's just like a round skinny thing that just, it's all down and no across. The platonic idea of a hole. If you want to ask the science couch, follow us on Twitter at SciShow Tangents, where we

will tweet out topics for upcoming episodes every week. Thank you to at Coleman Zephyros at Liz Cake Bug. And everybody else who tweeted us your question is this episode. Final Sandbuck scores a three-way tie for the lead. You'll love to see it. With two points for Hank, Sam, and Stefan, and nothing for Sari. Makes sense to me. And that means that Stefan has pulled into the lead with 39 points.

Sari has 38, Sam has 37, and I have 36. Still pulling up the back of the pack there. If you like this show and you want to help us out, it's real easy to do that. You can leave us a review wherever you listen. That's helpful. And it helps us know what you like about the show. Second, you can tweet out your favorite moment

from this episode. And finally, if you want to show your love for SciShow Tangents, just tell people about us. Thank you for joining us. I have been Hank Green. I've been Sari Reilly. I've been Stefan Chin. And I've been Sam Schultz.

SciShow Tangents is a co-production of Complexly and the wonderful team at WNYC Studios. It's created by all of us, produced by Caitlin Hoffmeister and Sam Schultz, who is also our editor. Our editorial assistant is Deboki Chakravarti. Our sound design is by Joseph Tuna-Medish. Our beautiful logo is by Hiroko Matsushima. 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. I think we can agree that anuses or some sort of hole that lets you get rid of waste are really important.

Ananteris scorpions can drop their stingers, so slash tails, to run away from predators. But the problem is, unlike lizards, the dropped tail piece also includes their anus, which doesn't necessarily grow back. They can still mate, and they can still eat, so it's like a last-ditch survival effort as they swell up with trapped poop and eventually die from what I think is constipation problems.

In lab experiments, they survived up to eight months without anuses. Oh no. So they just run around trying to have sex as much or as quickly as possible before their poop overflows, basically. I mean, if you got eight months. Yeah, that's true. You don't have to go that fast.

You probably have to look pretty hard to find another scorpion though, right? Or do you know where all the other scorpions live if you're a scorpion? I don't know how it works for scorpions, but I do know that it may be more difficult to attract a scorpion to your scorpion chamber if you are half a scorpion and you are slowly filling up with food.