Stuff You Should Know - How Blue Holes Work

Episode Date: February 18, 2021

Geologists and biologists have recently realized that the planet’s oceans and coasts are littered with a unique type of ecosystem called blue holes, submerged sinkholes that were once dry caves. They are turning out to be weird and amazing places. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Hey, I'm Lance Bass, host of the new iHeart podcast Frosted Tips with Lance Bass. Do you ever think to yourself, what advice would Lance Bass and my favorite boy bands give me in this situation? If you do, you've come to the right place because I'm here to help. And a different hot sexy teen crush boy bander each week to guide you through life. Tell everybody, yeah, everybody about my new podcast and make sure to listen so we'll never, ever have to say bye, bye, bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple podcast, or wherever you listen to podcasts. I'm Munga Chauticular and it turns out astrology is way more widespread than any of us want to

believe. You can find in Major League Baseball, International Banks, K-pop groups, even the White House. But just when I thought I had a handle on this subject, something completely unbelievable happened to me and my whole view on astrology changed. Whether you're a skeptic or a believer, give me a few minutes because I think your ideas are about to change too. Listen to Skyline Drive on the iHeart radio app, Apple podcast, or wherever you get your podcasts. Welcome to Stuff You Should Know, a production of iHeart Radio. Hey and welcome to the podcast. I'm Josh Clark and there's Charles W. Chuck Bryan over there and Jerry's hovering about and this is Stuff You Should Know, another Jazzy Earth Science

Edition Chuck. Yeah and this is like, I know we covered this head of an internet roundup. Did we? I don't think we covered, I mean we've done a lot of cave stuff. We did sinkholes, cave dwellers, caving, ice filialogy, and cave diving. So which one, like it could have come up in cave diving, I think. Maybe, but I feel like I remember showing a picture. I'm feeling an internet roundup. Okay, yeah, we've been, that's kind of funny because this then is the second thing we've done that we already did on internet roundup and then forgot about. That's right. That's a trend. We're trending. But the cool thing about this one, Chuck, is that like these things that we're going to talk about today, blue holes, are so new scientifically

speaking, they're so unexplored that there's a lot we can get wrong and no one will know for like 10 or 15 years. Perfect, we'll be done by then. Isn't that great? Yeah, we'll be sipping my ties on the beach earning 20% by then off German bearer bonds. What is that, trading places? No, that's diehard. Yeah, okay. I think that was a mashup. Oh, what? Yeah. That's funny how things just kind of invade your subconscious like that. Well, I mean, trading places, they definitely were sipping drinks on the beach, which did not happen in diehard. No, but he says- Did he say something like that? Yeah, yeah. He says by the time the FBI figures out what's going on, we'll be sitting on the beach. I think he says sipping my ties earning 20%. Does he say like in trading

places? That's right. Yeah, but he like breaks the fourth wall and stirs right at the camera when he delivers that line. That'd be great. So obviously, as everyone's picked up by now, we're talking about blue holes. And if you don't know what a blue hole is, I feel like this is definitely one of those ones where we need to define it rather than just start talking about it out of the gate. Define what it looks like or the reveal of what it is? Oh, okay. Yeah, we'll define what it looks like first. How about that? All right. Well, it looks like a blue hole in the ocean. Like, you know, there's ocean. Yeah. And then all of a sudden, it's like, wait a minute, there's a, you know, sometimes they're pretty circular, like almost exactly circular. Yeah. And sometimes they're

oddly shaped, but it's definitely like a different color. And what it looks like from a bird's eye view is like, well, hey, it looks like it might be deeper right there. And it is. Yeah. And it's a much, much darker shade of blue than the surrounding areas, because it's a deep, deep hole in the seafloor. And the stuff around it is usually far shallower, comparatively speaking. So usually the area around is like a much nicer, kind of lighter, blue-green, clearish color. And then this is like, this really stark, dark blue hole. Again, in the middle of the seafloor. And it's a, they're really popular diving spots. You have to be a really good diver, as we'll see, to dive on a blue hole. And they also have long for centuries been

known locally as really great fishing spots, both commercially and for sport fishing. But the thing is, it's starting to become clear to geologists and biologists that these things are kind of dotted all over the world. There's some out to sea, there's some that are actually landlocked, but that they share some commonalities. And that these things, these blue holes, submerged holes in the ground or the seafloor, are some of the weirdest, most amazing environments that exist on earth right now. Yeah. And you know, we should probably say that fishermen everywhere are probably still mad at Jacques Cousteau, who in 1972 put the great blue hole, which is one particularly striking blue hole off the coast of Belize. He put that on the map

in 1972 on a show that I used to love to watch, the undersea world of Jacques Cousteau. Did you watch that? No, I saw the life aquatic with Steve Zissou though, so close enough. Yeah, I was, I'm not sure what channel it came on or that was in reruns or if I was watching it live, but it was sort of like, you know, that and Mutual of Omaha's Wild Kingdom were the two big nature shows for me growing up. Yeah. As far as turning me on to all this stuff. You're right. The, I think the show ran from 1966 to 76, so it's entirely possible you were watching it live as a youngster. Probably reruns. Yeah, but still, I mean, I'm sure it immediately went into reruns. It was wildly popular. And that particular episode, if you're interested,

was Secrets of the Sunken Caves. But yeah, he put this thing on the map, like not literally, it was on maps already, but he introduced it to the rest of the world. And the great blue hole, as that one in Belize that he covered is called, is on basically every serious scuba divers bucket list to dive. It's just, it's just one of those places you have to dive before you die. Hopefully, you don't die while you're diving on it, but it does happen sometimes. It does. And blue holes are basically, you know, I mentioned sink or episode on sinkholes at the beginning. That was a bit of an Easter egg, because that's really all they are is underwater sinkholes. It's a feature of what's known as a karst system, K-A-R-S-T, where you have this porous limestone making up the bedrock,

which, you know, leads to a lot of things. It's porous. So it sedimented, like it wears away and erodes kind of easier, I think, than other kinds of bedrock. That's where, if you listen to any of the caving episodes, is where you're going to get some of these great stalactites and stalagmites, because that acid rain drips down and wears away that limestone. And, you know, it forms little icicles from the top. And then when it hits the bottom, it forms reverse icicles on the floor. And some of these blue holes have these stalactites and stalagmites, because they used to be, you know, they used to be land. Right. They used to be dry caves, like that's the thing. Once they found stalactites and stalagmites in these blue holes, out to sea, they're like,

oh, okay, this had to have been above dry land, because the dripping effect of water coming from the top and then dripping on the bottom, it's kind of lost in the translation when the thing is already submerged in water. It has to be dry, you know what I'm saying? You can't jump underwater? Not really, no. I think it just kind of goes every which way, rather than straight down. So yeah, when they started finding these collectively stalactites, which come down from the ceiling and stalagmites, which come up from the floor, they're collectively called speleothems, which we've talked about in plenty of other episodes. When they started finding speleothems in these blue holes, they're like, these were once on dry land, which is pretty cool. But it also

makes sense too that these are just caves that formed at some point in the great, great distant past on earth. I mean, where else are they going to form, you know? And it also makes sense that, as a cavern formed through the same process that forms speleothems, it's just the water kind of carves out a hole in the limestone, it dissolves it, and then it gets bigger and bigger over time, and then all of a sudden you have a cavern that the roof of that area is not supported like it is surrounding. And so it's eventually going to collapse in, whether it's on dry land as a sink hole, or if it's on dry land and then that eventually becomes submerged by water, you have a blue hole. So it's just a sinkhole that's now out to sea because the sea level rise, basically.

Yeah. And one of the cool things about the great blue hole is when they started looking at these stalactites and stalagmites, they're like, well, some of these look like you would expect because when things drip, they drip straight down or build straight up. But some of these are angled, sometimes up to 12 degrees. And they're like, that's pretty interesting. So what it probably means is that this thing formed over many, many, many years. And the earth tectonic plates started shifting. And so they started dripping at different angles. So you've got this really cool effect that happens where you have these, you know, something that you wouldn't see normally in a cave, basically. So a couple of years ago, Nat Geo and Richard Branson did an expedition where they were basically

tried to map the great blue hole, 3D map it, and they went down there and they, they went deeper than I think had been before in a submarine like that and found a bunch of stuff. They found that it was filling up very slowly. I think they likened it to like an underwater hourglass. It's very slowly. So it's not like it's going to be full anytime soon. They found a two liter bottle of Coke, a GoPro camera and some, some dead people, some dead humans, a lot of dead animals, but some dead humans as well. Yeah. So the blue hole has claimed at least three lives that we know of on record, right? Which is actually kind of a low ratio compared to some other blue holes out there. But they are still down there. And like you said, two of them were found by Branson and

the Nat Geo crew and they came back and told the authorities in Belize exactly where they were. And they also apparently said, but look, it's really quiet down there. It's really like a restful place. Like you could do a lot worse for a final resting place than the bottom of the blue hole in Belize. And I guess the authorities, I don't know if they consulted with the families or what, but I was made to think by some of the stuff I read that the authorities in Belize said, you know what, let's just leave them down there and that will be their final resting place. Which sounds a little morbid from the outside, but that's actually kind of customary when it comes to cave diving in particular. I think we talked about that a little bit in the cave diving episode.

Yeah, for sure. And the cool thing about the great blue hole is that at one point, it was in the jungle. Yeah. So that would make it a different kind of blue hole, which is still technically a blue hole, but it's called the Ankyline. I'm pretty sure that's right, pool, which is a blue hole, but it's landlocked. So like the rim is exposed to dry air. It's not underwater like on the seafloor because the sea levels just aren't that high. And one of the interesting things about the great blue hole in Belize is it was at some point, because sea levels lowered so dramatically during the last interglacial maximum about 26,000 years ago, that a significant portion of this vertical cave, which is now the great blue hole in Belize,

was dry. It was just totally dry. Like you could walk around the top of the rim, because it was no longer underwater. You could jump in, you would die, but you could jump in and you would go all the way down. And then maybe at about the bottom, say 20 meters of the cave, you would finally hit seawater. So over time, the seawater levels have risen from the last time the earth was in an ice age. And the sea levels have risen so much that now the cave is totally submerged and is actually many meters under the surface of the sea because of sea level rise. Yeah. And there's some really cool things you can learn from studying these blue holes. And maybe we should take a break and learn about those right after this.

this situation. If you do, you've come to the right place because I'm here to help. This I promise you. Oh God. Seriously, I swear. And you won't have to send an SOS because I'll be there for you. Oh man. And so my husband, Michael, um, hey, that's me. Yeah, we know that Michael and a different hot sexy teen crush boy band are each week to guide you through life step by step. Oh, not another one. Kids relationships, life in general can get messy. You may be thinking this is the story of my life. Oh, just stop now. If so, tell everybody, everybody about my new podcast and make sure to listen so we'll never ever have to say bye, bye, bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple podcast or wherever you listen to podcasts. I'm Mangesh Atikala and

to be honest, I don't believe in astrology. But from the moment I was born, it's been a part of my life. In India, it's like smoking. You might not smoke, but you're going to get second hand astrology. And lately, I've been wondering if the universe has been trying to tell me to stop running and pay attention. Because maybe there is magic in the stars, if you're willing to look for it. So I rounded up some friends and we dove in and let me tell you, it got weird fast. Tantric curses, major league baseball teams, canceled marriages, K-pop. But just when I thought I had to handle on this sweet and curious show about astrology, my whole world came crashing down. Situation doesn't look good. There is risk to father. And my whole view on astrology,

it changed. Whether you're a skeptic or a believer, I think your ideas are going to change too. Listen to Skyline Drive and the iHeart Radio App, Apple Podcast, or wherever you get your podcasts. All right. So there's a couple of really cool things that you can learn by studying blue holes. One of them is you can look at the sediment and you can basically kind of get a snapshot of ancient weather patterns. I think when Branson and the gang went down to the great blue hole, they found a lot of sediment where it sort of indicated that, in different areas, it indicated that perhaps the Mayan Empire had several severe hurricanes and maybe had something to do with them not being around for much longer. Yeah. Because so these blue holes are basically

at a certain level cut off from the ocean above them. There's a point where there's no currents any longer, where the waves can affect it, where there's no oxygen dissolving past a certain boundary that we'll talk about in a second. And so beneath a certain depth, they're just like this perfect record of the earth's geological history frozen and sequestered from everything else. So if you go down there and this is the kind of the trend that they're starting to figure out that these are the expeditions they're trying to launch and start taking samples of the sediment, you can get like a really good picture of earth's say like hurricane past or drought past. Apparently when there's spikes in iron content, they take that as from dust storms from Africa,

which says that there's probably severe drought around the world that year. So there's all of this information you can glean that's just trapped and locked in the bottom of these great blue holes because they're so deep and so remote and so unaffected by the world above them. I just think that's amazing. It's super cool. The other cool thing you can learn about is sea level rise over the years. We don't have the clearest picture in science of ancient sea levels. And when they were, you know, like exact levels of when there were glacial periods and interglacial periods and the rising and falling of the seas. But if you go down there and you radio carbon date these stalactites and stalagmites, you can compare them to the relative depths of the whole cave

system. And then you can basically say, when was there air here? When was there water here? And get a pretty, you know, at least a much better picture of what the sea levels used to look like. Yeah. And they figured out that the cave itself was formed between about 153,000 years ago to about 15,000 years ago. There were four major dry periods where the cave was exposed during that time. And I don't know if they figured out from the great blue hole itself or if they just already knew this, but apparently in the past, the sea level has risen really quickly a couple of different times. I think 11,000 years ago and 8,000 years ago, over the course of like less than 150 years, it rose 25 feet and then again 21 feet in less than two centuries, which is a really

significant rise. And having information like that is really vital to kind of placing our current sea level rise and experience of climate change in context, in this greater context of Earth's history and possibly its normal rhythms or what's abnormal. So to be able to understand that because of the kind of the record that's kept in the blue holes is extremely helpful. Yeah. And I think the usual level of sea rise is about a meter every century. Yeah. So a spike of 24 and 20 feet is really, really big. I mean, you could basically watch it happening, you know, it start to come up around your ankles if you stood in the same place long enough. Another cool thing about blue holes and in

particular the great blue hole is that there is a layer of hydrogen sulfide that basically acts like a blanket. And there are different depths depending on which blue hole you're talking about. But it's just a real concentrated layer of hydrogen sulfide that is, it's a byproduct of decaying plant material. And it's kind of stinky. It's kind of that sulfury eggy smell that you might smell sometimes. And it's really, really clear water below in this area. It is really brown and kind of gross. And then, you know, it's so far down, it doesn't look brown and gross from the top. It still looks nice and blue. But it's really a separation point where above it, you have life and below it, there's no oxygen getting through. So you

have no life. No. And I saw it described as like kind of a hazy brown kind of cobwebby layer. I think in the great blue hole in particular, it's about 30 feet thick. And it starts at about the 90 meter mark. And you have to go down past it. And I guess, it is creepy, but it's also apparently like, even though you have a rebreather on or scuba apparatus, it still seeps in through your skin while you're swimming through it. And people will like throw up and get itchy, kind of break out in hives, start to get nauseated and headaches because it starts to creeps in through your skin in just that short time. So it's really gross. It's really, really toxic in this concentrated form. It's like basically concentrated gas form suspended in a blanket

layer. And oxygen can't get past it. So it's an anaerobic environment in that lower layer, which means it should be totally dead and lifeless. But one of the things that they're finding out about blue holes is that even in this anaerobic toxic layer, there is archaea, another type of life that's not quite bacteria and definitely not eukaryotes or prokaryotes. I can never remember which one we are. But they live down there. They're extremophiles is what they're usually called these days. And there's a whole kind of teeming colony of life down there that actually takes all the stuff that accidentally falls into the blue holes and digests them and turns them into this bioavailable nutrient-wrench sediment that's just kind of trapped down at

the bottom of the blue hole. Yeah. And then the great blue hole, when they went down there, they saw, I think they described it as a, I say conch, they were saying conch. I'm not sure which is correct, but I've always said conch. But like a conch graveyard down there, basically, where it's just littered with all these poor little sea creatures that happen to fall below that layer and they can't get back out. And it's like silence of the lambs ask. There's even like scratch marks where you can tell they've tried to get out over the years and were unable to. Yeah, conch fingernails that have peeled off and are stuck to the sides of the walls. It's a bad jam. What do you think about that Clarice show? Is it going to be any good? I like the concept. Yeah, me too.

But I have a direct sequel, but I don't know. I saw that they seem to be recreating the lamb thing. And I think one of the, I just saw this movie like a week ago and it's still just so good. I think one of the strengths of it is that they don't show any of that story. It's all just Clarice and her telling of the story. Which makes it so much creepier. Yeah, there's no like flashback scene or anything. Right. So this TV show did that. And I'm wondering if that says a lot about it or not. I'm wondering who is playing Buffalo Bill because they recreate some of that stuff. It looks like. My friend, it's our old pal Tommy Chong, the note holder. He got himself a pretty sweet gig. He's playing him? No. It's like, man, I mean, they should just get that guy. He's around

and still creepy looking. Yeah. Yeah. James Gumb, the guy who played James Gumb. Yeah. Sure. Yeah. Why not? So where are we here? We were talking about little crabs and things trying to get up unsuccessfully, which really is super sad. Yeah. So there's a whole conch graveyard down. Who is saying conch? Were they British? I don't remember. Because I've always heard conch too. Yeah. There's a whole conch and hermit crab graveyard down at the bottom of the blue hole. And it is sad, but it's just kind of like the circle of life thing. But again, the weird thing about these blue holes is that some of them are not circles. It's all just a one way deposit of stuff from the top down to the bottom. And everything just kind of gets stuck there. And

again, forms this pretty cool record isolated in time. That's not entirely true of all blue holes. It is for the great blue hole and plenty of other blue holes where it's just like, things go in, they don't come back out. But there are other blue holes out there, including one called Green Banana Blue Hole in the Gulf of Mexico. I think off the coast of Sarasota. That is pretty deep. It's like 450 feet, I think 435 feet below the surface is the bottom of it. And it starts 154 feet below the surface. And it's some incredibly vibrant alive oasis in the midst of this relatively barren Gulf of Mexico desert. And they are trying to figure out what the heck is going on because other blue holes are just like life suckers. And this blue hole is like,

have some more life. You get some life, you get some life, and you get some life, you know? It's a pretty interesting conundrum. Does the Green Banana have that layer? Yes. Although, so I'm sorry, it doesn't have the layer, but it has plenty of hydrogen sulfide in it. There's some. Maybe that's the difference. There's some, yeah. And they're trying to figure out why, because there's another hole, a similar called Amberjack Hole that they've explored. And it definitely has a layer. But there's also some sort of nutrient flux or exchange with Amberjack too. But in the Green Banana, there's like, it's like a two-way highway going from the top to the bottom up to the rim. And what's interesting is they've figured out that there are microbes

there, I think archaea, that actually eat the inorganic carbon that leaches out of the dissolving walls of the cave underwater. It eats it and turns it into organic carbon, which then is, makes its way up somehow to the rim so that there's actually more life that can be sustained. There's more bioavailable carbon than would be there if those microbes weren't chomping on it and turning it into organic carbon. So it's pretty interesting stuff. And like, you don't find this kind of thing just anywhere. So they're starting to really figure out that like these blue holes are very unusual, unique communities, even compared to one another. But especially when you step back and compare it to like Topeka, it really knocks your socks off. Yeah. And these are, you know,

they're all underwater cave systems. There are parts of these cave systems that are still unexplored because they're so vast or so deep. And like you said, they're new and they're, you know, it's dangerous to get down there, even if you're Richard Branson in a fancy, you know, multi-million dollar submarine. One of the things in the ones off the coast of Florida that they're trying to figure out is whether they actually connect to the aquifers in Florida and whether or not that is the reason why there's some saltwater intrusion going on in the state's drinking water. Yeah. And it's possible that that flow of nutrients up and down the green banana has to do with some sort of tidal connection. So there's like a flushing mechanism. Maybe it could be from the aquifers,

they don't know. But that would be a big one to figure out because saltwater intrusion, especially down in Miami, is an enormous problem and will probably lead to that city being abandoned in the next 50 years. Poor Miami. Unless, I mean, we could always figure out desalination processes, but yeah, that'd be a town to save if you ask me. I love Miami. Oh, yeah? Oh, it's vibrant. I'm not the biggest fan, but, you know, it's not for everyone. Sure, no. But it is, I like it. I think it's a great town. Should we take another break here? Yes, let's. All right, we'll take a break and we'll finish up with diving in these things, I guess. Sure. Hey, I'm Lance Bass, host of the new iHeart podcast Frosted Tips with Lance Bass. The hardest thing

could be knowing who to turn to when questions arise or times get tough, or you're at the end of the road. Ah, okay, I see what you're doing. Do you ever think to yourself, what advice would Lance Bass and my favorite boy bands give me in this situation? If you do, you've come to the right place because I'm here to help. This, I promise you. Oh, God. Seriously, I swear. And you won't have to send an SOS because I'll be there for you. Oh, man. And so, my husband, Michael. Um, hey, that's me. Yep, we know that, Michael, and a different hot sexy teen crush boy band are each week to guide you through life step by step. Oh, not another one. Kids, relationships, life in general can get messy. You may be thinking this is the story of my life.

Just stop now. If so, tell everybody, yeah, everybody about my new podcast and make sure to listen so we'll never ever have to say bye bye bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple podcast, or wherever you listen to podcasts. I'm Mangesh Atikular, and to be honest, I don't believe in astrology. But from the moment I was born, it's been a part of my life. In India, it's like smoking. You might not smoke, but you're going to get second hand astrology. And lately, I've been wondering if the universe has been trying to tell me to stop running and pay attention. Because maybe there is magic in the stars, if you're willing to look for it. So I rounded up some friends and we dove in and let me tell you, it got weird fast. Tantric curses,

Major League Baseball teams, canceled marriages, K-pop. But just when I thought I had to handle on this sweet and curious show about astrology, my whole world came crashing down. Situation doesn't look good. There is risk to father. And my whole view on astrology, it changed. Whether you're a skeptic or a believer, I think your ideas are going to change, too. Listen to Skyline Drive and the iHeart Radio app, Apple podcast, or wherever you get your podcasts. So, okay, Chuck, like I said, Jacques Cousteau kind of said, hey, everybody, go check out the Great Blue Hole. It's amazing. But there are plenty of other blue holes out there that everybody wants to dive on. And we should say the Great Blue Hole is not just famous because of Jacques

Cousteau or it's not just noteworthy because of Jacques Cousteau. Not like he could have gone to just any blue hole and it would have been like the best known blue hole in the world. Like it's incredibly large. It's not the deepest blue hole on the planet. I think that one actually goes to one in the South China Sea called the Yongli Marine Cavern, which is about 300 meters, nearly 1,000 feet deep. This one is, I think, 415 feet deep. But it's 1,000 feet across. So, if you combine its width and its depth, it's the biggest blue hole out there as far as we've discovered yet. Yeah. And that's what makes it great. And that's what makes it a diving destination. But it is very dangerous. It is not something any kind of novice diver wants to take part in. In fact,

I'm not sure how they, you're probably not even allowed to unless you're at a certain level of diving ability would be my guess. I think it depends on how they can police that. Right. Yeah. That's my question too. I don't know how they police it all. I've read about one called Jacob's Well, I think in New Mexico or Texas, that some people died diving on it. And somebody tried to put up a grate that kept people out of the rest of the cavern system, and they just immediately removed it and kept going. So, I don't know how you would police that either. But it is dangerous because it's super, super deep. It's dangerous because of that layer of hydrogen sulfide that we talked about. I know we talked about the bins and quite a

few episodes, but nitrogen narcosis can happen at just 100 feet down. So, the conditions are just so different than anything you would normally encounter as a diver. You can't just use your regular rulebook and playbook and think everything's going to be just fine. It's very specific conditions. You really got to know what you're doing as far as blue hole specific diving goes. And like we mentioned earlier, those three people died, at least three people. There's probably been more, I would guess, but three verified people have died in the great blue hole alone. Yeah. From what I saw when you dive a blue hole, it's a combination of technical diving, which is like really, really deep diving that requires all sorts of planning and skill,

combined with cave diving, which requires, like we talked about before, all sorts of finesse. Like if your flipper just flicks one of these speliathems, it just dissolves into a cloud of silt and you don't have any idea what's up and what's down any longer. So, it is really, really tricky. And people do die. You saw that one article I think I sent from fizz.org, I think, where it was talking about them searching the cave system under Dean's blue hole in the Bahamas. And they came across a diver who was still wearing his 1970s scuba equipment and had been left in place there after dying there. So, it's like really, really dangerous diving. And there's a blue hole in Egypt that's considered the graveyard, the diver's graveyard, I think.

So, that diver looked like Brad Pitt in Once Upon a Time in Hollywood? Basically, I mean, wouldn't that make it exponentially creepier to just the fact that it's like 70s diving equipment? That's just something about it would make that horrifying to come upon in a dark cave. It's cooler looking. Oh, yeah. For sure. They should have never progressed past that design into the, you know, Mountain Dew electric yellow kind of thing that they've got going on today. Yeah, back when they were called skin divers. Exactly. I don't even know what that means. I don't either. I don't either because you usually are wearing a wetsuit. Maybe it's like the opposite of dry suit diving, I don't know. Who knows? Everybody in the 70s

was stoned on pot, so you can't make heads or tails of what they were talking about these things. Blue holes are also a good place to go if you're a free diver and if you're interested in setting any kind of a free diving record, a blue hole is a great place to go, even though it's dangerous, because it's super deep. We talked about free diving before, but that's, you know, that's diving without the scuba gear. It's people that can hold their breath really, really long time, people that can, whose bodies can adjust to those depths better, I guess, or maybe they're just trained to adjust better than other people. Yeah. And I think it was the site up until semi recently where they actually had a competition there called vertical

blue, where they have set rolled records, but I don't think they do it there anymore, right? I don't know if they hold vertical blue or not, but there is a type of free diving called no limits free diving, which is, I think they stopped recording records because they didn't want to encourage people to do this any longer. Sounds terrifying. It's like the most extreme version of one of the most extreme sports there is. Free diving on its own is just crazy nuts, but no limits free diving is where you have, I think flippers on in a wetsuit and a mask, and that's it. You just take a deep, deep breath and hold it, and then you take a weighted sled that pulls you, plunges you down to the depths of the blue hole very, very quickly. And then

when you reach the level that you're trying to reach, usually to set a new record, you grab onto a buoy that's down there and it takes you back up really quickly. And I was like, how can you not get the bends? And the key is, the trick is you're not breathing at depth. You're just holding your breath. Yeah. When you breathe at depth, that's how nitrogen bubbles can get dissolved into your bloodstream. If you're just holding your breath, I guess that that could happen, but I think it's much less likely for it to happen. Either way, it's not, it can't possibly be good for your body, because these guys are holding their breath for nine minutes I saw in one case. You shouldn't do that. Yeah, I mean, I can't imagine what it does

to your body going that fast down and then that fast back up again. Yeah. Like I can't go eight feet down in a swimming pool without my ears doing something funny. You just come up like, ow, ow, ow. It didn't hurt, but I don't know. I mean, obviously it's practice and training and all that stuff, but I say no, thank you. Yeah. And so we should tell people, like with the depths we're talking about, the guy who holds the record right now is named Herbert Nitch. He dove to 702 feet like this back in 2007. And in 2012, he did it again, this time to 831 feet, but by that time they weren't recording records any longer. So it's an unofficial record, but 831 feet on a breath and then back up. That's nuts, man. So you can

imagine that when people try this stuff, they die sometimes. And at that vertical blue competition at Dean's Blue Hole, which is an Anki Allen pool up in the Bahamas, a guy named Nicholas Mavoli died back in 2012. Very sad. It is. It's a very dangerous thing to do free diving. It's also a dangerous thing to do diving on blue holes, but I guess it's one of those ones where that you work toward a goal and you finally get to do it and your life has changed forever, kind of. Yeah. You got anything else? I got nothing else. I don't either, man. If you want to know more about blue holes, there is a lot to learn out there. So just start researching and thank us later. And since I said thank us later, it's time for listener mail.

This is a good one. This was in response to the NAACP episode. Okay. Hey guys, just finished listening to NAACP. Made me think of my father's college days. He attended Ole Miss when James Meredith joined the school and one day saw an opportunity to help a young field reporter named Dan Rather move his equipment from the registration building to the library. My dad kept in contact with Mr. Rather and let him know that he was actually living in the same dorm as Mr. Meredith. And that is how his time as a stringer began, providing mostly audio clips of events happening at the school. He said at the time he was selling reels to CBS, ABC, CBC and the BBC making around six to eight hundred dollars a week, which is real money for a college kid in the 60s.

Yeah. And I mean, that's real money now. Yeah. It was only a matter of time before the university found out who's providing the footage and offered my dad the choice of stopping or being expelled. He opted for expulsion thinking he could just enroll in another college, but then learned that his transcripts were flagged and he could not just pick up and move to another school. So he had to go, I know, right? So he had to go back to Ole Miss and promise not to report anymore so he could finish and get his degree, which he did. Several years later, he married my mom and they took a trip to the CBS studios near them. And my dad suggested they pop in to say, hi to Dan Rather. My mom thought he was pulling your leg. They went to the studio, asked to speak

to him and was promptly asked if they had an appointment and was turned away. As they were leaving, Dan Rather walked by and said, John, last name redacted. How the heck are you? Curse word redacted. And according to my mom, she almost fainted. Anyway, my family has always taken a lot of pride that my dad helped shed light on the integration at Ole Miss. Granted, his role could have been filled by almost any of the students living in his dorm, but he was the one who did it. And that is Brenda in Sarasota, Florida. That's a great story, Brenda. And that jibes quite well with our blue holes theme because there's some office Sarasota, too. Totally. That's great. Yeah, the University of Mississippi was

like, you better stop reporting. Now get back to class in journalism school. Right, exactly. Well, thanks again, Brenda. And if you want to get in touch with us like Brenda did, you can send us an email to stuffpodcastatihartradio.com. Stuff you should know is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app. Apple podcasts are wherever you listen to your favorite shows. Bye, bye, bye. Listen to Frosted Tips with Lance Bass on the iHeart Radio app, Apple podcast, or wherever you listen to podcasts. I'm Munga Chauticular, and it turns out astrology is way more widespread than any of us want to

believe. You can find it in Major League Baseball, international banks, K-pop groups, even the White House. But just when I thought I had a handle on this subject, something completely unbelievable happened to me, and my whole view on astrology changed. Whether you're a skeptic or a believer, give me a few minutes, because I think your ideas are about to change, too. Listen to Skyline Drive on the iHeart Radio app, Apple podcasts, or wherever you get your podcasts.