The Pressure

I don't know about the worst. I mean, generally it just involves megan a mass like splat splattering something, not covering something appropriately, so you have to not only remove your food from the microwave, but then scrub it out. I remember there was one day not too long ago. I think it might have been like on New Year's this year or something that within the same day, I think I tried to microwave butter to melt it and

it exploded in the microwave. But then I also tried to microwave a soft boiled egg to heat it up and it exploded. Uh so, I don't know. There's a lot of exploding the microwave. But there's another kind of microwave mistake where we use this radio range of ultramodern convenience uh to to maybe maybe do a little less troublesome damage than than blowing up an egg, but at least causing frustration. When you warp lids of containers in

the microwave. You've ever done this? Uh? So you know you want to heat up some food, maybe you just want to sterilize a bowl full of mud or something, So you put it in a glass bowl with a tight fitting lid or you know, tight fitting plastic, tight

fitting rubber lid. Uh. You know you maybe shouldn't do this, but you forget, but you cover it up with something that fits tight, and you microwave it and it gets piping hot, and you leave it standing in the microwave for a minute, and then when you check it, the lid or the plastic wrap or whatever you've used to cover it has been sucked down into a concave depression over the food. It has turned your you know, if it's a permanent lid, it has warped it maybe or

you've caused trouble. And the way we normally think about these kind of things is that when something like this happens, the lid or the plow stick was sucked down. But think about why is that happening. What's actually happening there? What's the attractive force pulling the lid of the container down into the food? Obviously it's not gravity, right, The food isn't like a star pulling things into its orbit. And it's not electromagnetism. The food isn't a magnet attracting

an opposite charge. It's not like the strong force that holds atomic nuclei together. So what's the attraction there? So superdnse potatoes are out of the question. No, though those can be a big problem. That's why when you make a big potato, fun fact, you should cut it open right after you pull it out of the oven. Don't leave it to sit there forever it turns into a rock. No. Counterintuitively, strangely, what's happening when that lid gets pushed down is the

atmosphere pressing on it. When the lid bends, what you're witnessing is the weight of the air we breathe. And it's a powerful Wait, it really is, but we don't norm normally notice it. Like, how come the atmosphere only pushes a depression into the lid after it's been microwave? Why doesn't the atmosphere, bend the lid when it's just sitting on the counter at room temperature. One thing you might be thinking is, okay, maybe it heats the lid up and this like sort of melts it or something

and makes it more appliable. But no, that that's not necessarily the case. It's because of the power of condensation. After you microwave a bowl of food containing water, a lot of the water in that food is turned into steam or water vapor. And of course when liquid is turned into a gas, it not only becomes hot, but it expands. It takes up more space, and it expands

to fill evenly all the space it can. So the spots inside the sealed bowl are not occupied that are not occupied by food, they get filled with hot, high pressure steam. And of course we know one thing that can happen here as as water turns to steam inside a sealed container is it can make the container explode. In some cases, that's what happened I think with my egg, Like the yolk is turning to steam and it had

to expand, and so the egg blew up. But if your container doesn't expand, it just fills with high pressure steam. And then when the microwaving stops, the contents of the bowl cool down again. And what happens, well, the steam that had filled all these voids in the bowl starts to lose energy, it cools down, it gradually converts back into liquid water. And this process, of course, is known as condensation. It's the same reason that dew forms on the outside of your cold soda can on a warm day.

The cold can is converting water vapor in the air into liquid by cooling it. But if the bowl in the microwave has a tight fitting lid, or it's wrapped tightly in plastic, what happens when the water converts from a gas back into a liquid while it takes up less space and it exerts less pressure on the inside of the bowl. Thus, a covered bowl becomes a low pressure environment or a partial vacuum. Without air pushing back

at the same pressure on the lid from below. The atmosphere leans hard on the it and it presses it down into the evacuated space, the vacuum, punching it into that bowl shape. So what you're seeing when the when the lid bends down is the footprint of the atmosphere, and of course The reason the lid doesn't normally warp informa bowl when it's sitting on the counter or whatever is that the pressure is equalized on both sides. There's atmosphere below it as well. The partial vacuum created by

the condensation of steam changes. That evacuates the space in the bowl as the steam condenses into water, and then the atmosphere comes in. And this is such a This a wonderful, mundane little way of seeing something strange and amazing. The power of atmospheric pressure. Yeah, you know it, you know. Normally, when I observed this, my main thought is, oh, I hope I don't break the plastic top to my glass of food storage container, because I'm down to like one

plastic top. They're all eight glass containers. But but yeah, this, this is an interesting way of looking at it, to see it as the footprint of the atmosphere, the weight of air actually observed. It's funny how it can be so powerful and we're so blind to it most of the time. I want to tell a related story about a about a seventeenth century Prussian mayor. How about we go there. Okay, so this guy is named Otto von Garica. He lived from sixteen o two to sixteen eighty six.

And uh. In addition to being a lawyer and a politician, he was, as I said, a mayor. He was an important engineer and physicist in history, and he had all kinds of scientific accomplishments. For example, in the sixteen sixties he invented what is believed to be the world's first known electrostatic generator, which is a device for generating electrical potential. Now, we talked a bit, you remember, Robert, about the history of electrostatic generators on the I think it was the

episode about the electric arc thesis, right, Yes, I believe so. Yeah, But for a brief refresher, these early generators were generally based on friction, kind of like how you can build up an electric charge on yourself by scuffing around on a carpet. Von Garrika discovered that he could build up a charge on a ball of sulfur if he rotated

it rapidly with a crank to rub against things. And he eventually discovered that building up a charge in this way could cause the sulfur ball to glow in the dark. But this wasn't Von Gerrika's only cool invention. Demonstrating like the potential of vast hidden powers in the world. He was also interested in the power of vacuums and voids, and in the weight of the atmosphere, which, as we

were just saying, usually goes unnoticed by us. So Von Garrika was the mayor of a city called Magdeburg, and around sixteen forty nine or sixteen fifty or so he invented the first known air pump which could be used to remove gas from a closed container. And by using this pump to create a partial vacuum, he was able to conduct fascinating research on the nature of voids in

empty space. For example, he discovered that light could pass through a vacuum, but sound could not, and like so, given what was known the in the sixteen fifties, how could that be? You know what? What was causing that fascinating? But then also in a series of public experiments following this, he demonstrated the power of a vacuum, or more precisely, the power exerted on a vacuum by air pressure, in a really awesome way, with an experimental apparatus that came

to be known as the Magdeburg hemispheres. So Von Garica had this air pump of his and he created two precisely fitted copper hemispheres to like hollow half spheres that together, if you fit them together, they would make a closed hollow sphere that was about thirty five and a half centimeters in diameter. And these spheres were constructed with a valve so that they could when they were pressed together

to create an enclosure. Varna could attach his air pump to the valve to force the gas out of the hollow sphere and create a partial vacuum inside. And here's the mind blowing part. Once the gas had been pumped out of the space between the two hemispheres, these copper domes could not be pulled apart, even when they were tied to horses pulling them in opposite directions. And yeah, it's and I want to be clear, like, there's no device holding the two hemispheres together. They weren't glued or

latched together or anything. You just press them together with a relatively air tight seal, pump the air out of the middle, and they stay so stuck together that even horses pulling at each end couldn't separate them. So we ask again, what's holding these half spheres together, just kind of like what's pulling the lid of the microwave container down, just as was the case with the bull in the microwave. If you're imagining some force inside the spheres sucking them together,

that's not accurate. There is no real sucking in a way, sucking is an illusion which you know there'll be a good motivational poster almost um. The real force here was the weight of the atmosphere, the pressure difference between the outside of the sphere and the inside. So you can sort of imagine the Earth's atmosphere reaching down with two huge, invisible fingers and pressing the two hemispheres together while the horses tried to pull them apart. And to separate the

spheres you would have to overpower that push of the atmosphere. Now, of course, an easy way to separate them is just to just open the valve and allow the air to fill the sphere um and then of course they'd come apart instantly because the pressure pushing out from the inside would be the same as the pressure pushing in from the outside. And that I love these kind of experiments, the kind that suddenly demonstrate in sharp relief amazing forces

that are always there. They're always present, but they're invisible to us from moment to moment. An atmosphere pressure is like this, it's our whole world. We spend our whole lives in it. We evolved in it, we're adapted to it. It permeates our bodies, so we don't feel or notice it. It's just completely invisible to us. But if you merely create a vacuum inside two half spheres, the familiar becomes strange again, and these fingers of the atmosphere come pressing

down and the sky becomes so heavy it's kind of frightening. Well, let's break things down a little bit into about pressure itself. What is pressure? Well, pressure is actually fairly simple. Has two components. It has force, and it has an area over which that force is applied. And this is why you often hear pressure explained in terms of like pounds per square inch. Right, So pressure is not Pressure is not just the amount of force pressing on something, but

where that force is being applied. So one way of thinking about this is like, why do so many weapons have sharp points and blades or not just weapons, I mean any kind of like piercing object it's because they take the force of your swing or thrust or push and they apply it to a smaller surface area, increasing the pressure on that surface area and usually doing more damage or getting through what you're trying to separate. Now, when we start then up applying this to Earth's atmosphere, uh,

it really gets fascinating. Uh. And this is a topic I I really enjoyed researching several years back when I wrote a piece called How Weather Works for How Stuff Works, probably one of my favorite articles that ever worked on UM. And one of my sources on that was a book called The Atmosphere Planetary Heat Engine from twenty from two thousand and seven by Gregory L. Vault and so member some of these figures are his figures, I believe from

that book. But UM, the Earth's atmosphere, if you were to weigh it, it would weigh in at a whopping five point five quadrillion tons. That's a fourteen zeros trailing after it. So you know that's that's a lot of mass. And it's actually it's the driving force behind air pressure. So one one analogy that I kind of like to turn to here is like if you imagine a squad

of cheerleaders forming a human pyramid. The cheerleaders on the bottom have to bear the weight of all the other cheerleaders on top of them, while the cheerleader on the top doesn't have to bear, you know, any of the weight. A similar situation exists in the atmosphere. The air is least pressurized at the edge of space, where it's a little or nothing pressing it down. The air at sea level, however, is weighed down by all the air on top of it.

Um like those pool poor cheerleaders shoring up the pyramid. All this pressure presses the molecules in the lower atmosphere closer together, and that means that the higher the air pressure, the greater the air density. And for this reason alone, fifty of Earth's air exists below an altitude of three miles or five kilometers, right. And that's one reason it actually becomes kind of difficult to say exactly where the atmosphere stops, right, because the atmosphere doesn't there's not like

a dividing line where it stops. We've kind of imposed some arbitrary dividing lines where we say, well, conventionally the atmosphere stops here, but it just keeps getting thinner and thinner until you go up until you basically realize, well, I guess I would call this empty space. Yeah, that's right. There's not like a membrane or anything up there. So standing at sea level, the atmosphere exerts, on average, a pressure of fourteen point seven pounds or six point seven

kilograms against every square inch of your skin. Now, I've also seen this figure slightly differently before the National Oceanic and Atmospheric Administration. Uh they say fourteen point five pounds per square inch, and uh per square inch it's p s I. So when you hear say P s I later, that's what we're referring to. I find this interesting to think about. Okay, fifteen pounds per square inch again that we just totally take for granted. And I know each

of us recently acquired a fifteen pound gravity blanket. This is not a paid plug, not a paid plug, but just to to illustrate, it's a blanket the ways fifteen pounds and you pull it over your body and it presses down on you and this kind of like uh comforting in human hug and uh So when I was researching this, and I was adding that into my notes about the fifteen pounds, I was like, oh my goodness, I gotta I gotta bust the gravity blanket out and

and feel what fifteen pounds feels like, or rather what fifteen additional pounds feels like. Yeah, but there's one of those for every square inch of your body. Yeah. Yeah, So it's it's crazy to think about that. Now we've already sort of explored this, but you you might begin to wonder about Okay, so there's a lot of square inches on my body, uh, and fifteen pounds alone that can start to feel pretty heavy, even distributed just over the entire thing in a gravity blanket. How come I

don't feel just constantly weighed down by the atmosphere. Why isn't it a crushing force that prevents me from doing anything? Well, I guess there's kind of like two answers to that. I mean, one is this is the norm, this is what you are used to. And then there's also you know, I've I've seen it written. You know that basically you're the fluids in your body are pressing out with the same force, so everything is there's equilibrium there, right, we

are at equilibrium in this pressure. It's what our bodies are evolved to existent. If you brought in, you know, an alien from outer space that I was living, I don't know. I was living in a super low pressure environment.

That's how its body had been formed, and then you brought it to the surface of Earth, it might well be crushed like a like a tin can a right, and then there might be issues with with the density because one of the issues too, is that if you venture above sea level air pressure uh, and it's corresponding density will decrease. That's why it's more difficult to breathe

a higher altitudes. Yeah, that's why it would be you know, you've you've probably heard stats like if you were to teleport to the top of Mount Everest, Uh, the difficulty you would you would have in getting enough air into your body to stay alive. Oh yeah, And this is

this is something that's really interesting. I want to linger on this for a moment, because we've established that we've got this really powerful, fascinating force of atmospheric pressure always affecting us, but we don't normally notice it because we're we're acclimatized to it, we're in equilibrium with it um and we only normally notice its effects by its absence. When we're at low pressure, that's when when you start

to notice what air pressure is. And of course, as you're saying, when you climb a mountain and reach a higher, high enough altitude, atmospheric pressure is lower. There's less atmosphere sussing down from above, so the air is less dense, meaning every time you take a breath, you literally get fewer oxygen molecules. They're just it's less dense. You're getting

less with each pull. Yeah. This is also the very reason that in your airplane safety videos they stress that if the cabin loses pressure, because little masks are going to fall down and you need to put them on in order to keep breathing right or you will very quickly encounter hypoxia, you know, like lack of oxygen and the breaths you take, and that of course can lead to all kinds of bad stuff in the body. You

need oxygen continuously immediately. And of course, so what this means when you get up to a high altitude, as it can lead to a heavy breathing in order to compensate for the lack of oxygen and each breath, uh and all kinds of stuff weakness, dizziness, potentially dehydration or

even loss of consciousness. I've experienced high altitude environments. I assume you have at some point as well, and it's it's a kind of alarming feeling, you know, like you suddenly go up like ten ft worth of stairs and like normally that wouldn't be a problem, but you're start

you're feeling lightheaded. And I remember encountering this on a trip to Arizona where we be We began in Phoenix and then we were heading up um, you know, rising in altitude as we were heading eventually towards the canyon, the Grand Canyon, UH. And I think we're somewhere in your Flagstaff where we stopped, got out and had his

beautiful walk. The leaves were golden. But I also think we were like it was like we we that the altitude changed as such that we felt maybe like a little more exhausted by the walk and everything seemed like

a little more magical in a weird way. Yeah. Yeah, I definitely experienced this sum when I was up up in Canada, when like we went on the hike to the Burgess Shale National Park area and uh to see the trilobyte beds up there, which if you haven't done, I highly recommend, but researched the hike before you do it. But also I've experienced this like in New Mexico and the mountains around Albuquerque and Santa Fe which can get really high elevation sition and you really start to feel it.

Of course, altitude sickness can vary a lot in where it sets in. It's usually said that it begins somewhere around fifteen hundred to three thousand meters above sea level, but it varies a lot from person to person. And I kind of wonder about something. This got me thinking about the prevalence of beliefs about the sacred or religious significance of mountain tops. Like so, there are tons and tons of examples of sacred mountain tops or beliefs about

the religious significance of mountain peaks around the world. There's, of course, you know, familiar one to us, mount Mount Olympus, the home to the gods in Greek mythology. But they're just literally hundreds of sacred and holy mountains around the world that are either homes of the gods or peaks of sacred pilgrimage, or places where people go to meditate, you know, near mountain peaks, mountain top monasteries considered sacred

in some forms of Buddhism and all that. Um I was thinking about Mount Kailash or Kailassa into bed Ah. So you're saying mountaintops where the air is thin and the gods are near. Yeah, I wonder. Now I'm not sure, but there could be a lot of reasons for belief in the mountaintops being homes of the gods or sacred places in general. And I think there's one clearer piece of evidence that not all beliefs about sacred mountain tops have to do with altitude, because many of the holy

mountains of the world aren't even that tall. I was thinking about there's one in Japan called, I think Mountain Mihwa that's like not even five So it's clearly not like an altitude sickness thing going on there. So there's obviously there are obviously other things contributing to these types of beliefs. But I wonder if one factor contributing to the widespread prevalence of belief in holy mountains is altitude sickness.

As you climb toward the top of a very tall mountain, you're very likely to experience heavy breathing, weakness, dizziness, dehydration, loss of consciousness. And I can even imagine these like mundane types of physiological obstacles presenting too ancient mountain climbers a kind of invisible power of magic or repelling force that attempts to bar entry or repel you from the sacred domain of the gods. Interesting. Oh yeah, I like

this hypothesis and actually does go farther than that. Like Apart from the mere hypoxic conditions caused by low air pressure at altitude, there are plenty of records of high altitudes, especially like above six thousand meters according to a nine study by Bruger at all that I was looking at high altitudes causing fascinating psychological effects like so esthetic illusions, which are when you imagine there are distortions in the schema of your body and various forms of hallucinations such

as hearing voices. You know people hearing voices on everest You might have ye, definitely yeah, Or there's a common one of sensing the presence of an unseen companion on

the climb. Sometimes known as third Man's and so I don't know about that, but that's an interesting hypothesis to work with, And I think maybe we should come back and do a whole episode in the future about the science of sacred mountains and mountain top psychology and and maybe explore a little bit further whether there's something to

this idea. Huh uh. It makes me wonder too about the science fictional applications here where you could have say, a society where um, they basically have a low air density chambers in which one uh visits to to meditate and receive the gods. Oh yeah, I wonder kind of a riff on a recent Peter Watts short story that I read called a Word for Heathens. Oh man, yeah, you made me read that one. That was great. It's sort of uh well, I don't want to spoil what

it's about. If you're into Peter Watts, you should check it out. Yeah, yeah, it's it's in his a short story collection of his. It came out in recent years. All right, Well, on that note, we're gonna take a quick break. But when we come back, we're gonna go underwater and we're gonna talk about water pressure. Thank you thank alright, we're back. All right. So we've been talking about atmospheric pressure so far. I don't know if we

ever really announced the topic today. We we just generally wanted to talk about some thoughts about pressure pressurized environments or unpressurized environments, and so we've been talking so far about the hidden effects of atmospheric pressure. But we should talk about water pressure because that's where the real pressure comes in on Earth. Absolutely, So yeah, when we go into water, pressure increases. And because the ocean is also a massive layer on the Earth, held in place by gravity,

and it weighs a lot as well. Uh, estimated weight of the ocean is generally generally's generally the standard estimation is three hundred and twenty six million trillion gallons. That's three two six with eighteen zeros on it. Zeros it is. But by the way, this is a something that is that that I found kind of fascinate. Water is practically incompressible, but it can be compressed with great difficulty for industrial purposes. Yeah, I guess I've usually seen it expressed as liquid water

being incompressible, whereas gas is compressible. Yeah, here's another fun fact about just the size of the ocean. If you removed all the continents and just had our oceans. Uh, you know, the global ocean itself covering a uniform plane of rock. The entire planet would be covered in a two mile deep ocean. That's just how much there is. Um starts to make you a little nervous. Yeah, so um.

Basically though, everything I said earlier about about the cheerleaders and atmosphere holds true for the for the ocean as well. Venture into the sunlit shallows and you feel a gradual increase in the pressure around you. Uh. I mean all you have to do is go underwater in a swimming pool or swim down from the surface while snorkeling to fill the pressure on your ear drums. That's hydrostatic pressure the foce per unit area exerted by a liquid on

an object. Now, according to the National Oceanic and Atmospheric Administration, for every thirty three feet or ten point zero six meters you descend into the ocean, the pressure increases by fourteen point five p s I and that was the same as the pressure of the atmosphere at sea level, which is why this is usually referred to as the unit of measure one atmosphere exactly. Yeah, you go down there, So you go down thirty three ft, you've got one

atmosphere of pressure. You go down sixty six ft, you have two atmospheres of pressure. So at a depth of five thousand meters, the pressure will be approximately five hundred atmospheres, or again five hundred times greater than the pressure at sea level. The average ocean depth is about twelve thousand, five hundred sixty six feet or about thirty eight hundreds,

so that's roughly three d eight atmospheres of pressure. And the greatest ocean depth is what thirty six thousand, two hundred feet uh over eleven thousand meters, so that's roughly um eleven hundred atmospheres of pressure. And I've seen I've seen the pressure at the bottom of the Mariana Trench listed as ten seventy a t M. Well that lines up about right. But I mean the point here being you can't I think it is sort of impossible for you to imagine the pressure at the bottom of the ocean.

You don't have something that it feels like to compare that too. But it is crushing pressure. Obviously, if an organism were to go into that that was not biologically adapted for it, it would be just instant death, just destroy you. Yeah, it's it's difficult to really grasp even in even in like our better works of science fiction. I mean, we mentioned Peter Watts already. Peter Watts has written a uh, several different books that take place in

ocean depths. Is novel Starfish, especially that I've discussed on the show before. Uh, there's a frequent mention of the underwater habitats and the and the the Rifters on that having to cope with three atmospheres of pressure in the area that they're um hanging out and uh, and there's also in a later Rifter Books Books book he describes the crazy cutting potential of a strip of water shooting through a crack in a hole, how it could potentially slice a character's arm right off. Um. And that is

that ill? You think that that is accurate? I think so, yeah, I mean based on what we're talking about earlier about potential industrial um applications of you know, high high pressure water streams plus Watts you know, tends to get the science right. I tend to. I tend to trust him on on the science and his books. Uh well, yeah, I mean, I guess I think about the fact that there are actually water jet cutters, like we're in industrial

water saws. There's also an interesting account from William Beebe, you know, the the the inventor and tester of the bathosphere that we've discussed in the show before. Yeah, if you haven't heard our Bathosphere episodes, you should go back and listen to those. But the basic idea, right, he got in a he got in a giant metal ball

and just descended into the ocean. Right. And there's a there's one he wrote about all of this, And there's one particular passage that's frequently brought up as an example of extreme uh you know, the the of of extreme water pressure and this one that was actually included on

the n O a A website. Um, but basically this would have occurred what I think nineteen thirty two, in which they sent the bathosphere down this again this uh, this iron beach ball of a of a vessel with one window with the one yeah, I think later they had three, right, Yeah, but at any rate, uh, just like these quartz portals to to look out of, right, and uh so they were going to test it out. Nobody aboard. They lowered it down to three thousand feet,

and then the following happens quote. It was apparent that something was very wrong, and as the bathosphere swung clear, so they just they just pulled it out of the ocean. After this descent, I saw a needle of water shooting across the face of the port window. Weighing much more than she should have, she came over the side and was lowered to the deck. Looking through one of the good windows, I could see that she was almost full

of water. They were curious ripples on the top of the water, and I knew that the space above was filled with air, but such air as no human being could tall rate. For a moment, unceasingly, the thin stream of water and air drove obliquely across the outer face of the quartz. I began to unscrew the giant wing bolt in the center of the door, and after the first few turns, a strange, high singing came forth. Then a fine missed steam like inconsistency shot out a needle

of steam, then another and another. This warned me that I should have sensed when I looked through the window that the contents of the bathosphere were under terrific pressure. I cleared the deck in front of the door of everyone's staff and crew. One motion picture camera was placed on the upper deck. In a second when close by

but well to one side of the bathosphere. Carefully, little by little, two of us turned the brass handles soaked with the spray, and I listened as the high musical tone of impatient, confined elements gradually descended the scale a quartertone or less at each slight turn. Realizing what might happen, we leaned back as far as possible from the line

of fire. Suddenly, without the slightest warning, the bolt was torn from our hands, and the math of heavy metal shot across the deck like a shell from a gun. The trajectory was almost straight, and the brass bolt hurtled into the steel winch thirty feet across the deck and sheared a half inch notch, gouged out by the harder metal. This was followed by a solid cylinder of water, which slackened after a while to be to a cataract, pouring

out of the whole of the door. Some air mingled with the water, looking like hot steam instead of compressed air shooting through the ice cold water. If I had

been in the way, I would have been decapitated. Wow. So, if I'm understanding correctly what he's saying happened here is they lowered it down without any people in it, to this greater depth than they normally would have allowed it to get down to see what would happen, and it somehow sprung a leak, despite the fact that this is a super reinforced uh you know, like it's not like it had a lot of components to fail. It's just

a metal ball with like extremely thick windows. But something happened in the courts of the window and water got in and because of the pressure where it was, not only did it fill with high pressure water, but the air inside it would have been super compressed by the water filling it up at such high pressure. So it's basically like a bomb they had they had pulled up

into the boat. Yeah, because normally the idea is it contains surface level air pressure within this high pressure ocean deep but but it kind of reverse things, right, so when they pull it back up, it's this steel ball containing all of this high pressured air and water. Yeah, there's something very frightening about that, like terrified to think, Um, I don't know about just like the the the killing power of water and air under such high pressure that

there aren't like explosives in this thing. There's not like a you know, it's not a gun or a bomb that has chemicals and it may do it's just the pressure. Yeah, well and and but but it's yeah, when you have situations through human technology to create this vast deferential like a difference in pressure water pressure or air pressure that

should be separated by dit by greater distances. And indeed that's where we see some of the more unfortunate accidents that have occurred with like, ah, like rapid deep pressure ization, which we may touch on a little bit in a bit, but we're not going to get you know, into a whole bunch of gordy details on that matter here, well except maybe a bit as it concerns fish. Yes, well

that's true. But uh but but just you know, as long as we're talking about atmosphere in the deep here that it brings up an important fact that increased pressure changes how our body interacts with certain gases, namely nitrogen. Increased pressure allows more oxygen and nitrogen to dissolve into the blood into the blood stream and it end at a mirror a hundred feet. Nitrogen levels can reach dangerous levels, resulting in nitrogen narcosis if not managed. Yeah, and this

actually goes beyond just like respiraated nitrogen and air. There are multiple types of molecules and chemicals inside the body that actually take on different properties at different pressure. It's kind of the same way that if you're experimenting in a laboratory, you can change the properties of a chemical or molecule by increasing or decreasing its temperature. You can also change the properties of a molecule, compound or whatever

by increasing or decreasing the pressure which it rests. And uh and so yeah, we'll we'll talk about that more in just a minute. I was looking up, you know, a little bit more about the effects of diving on the body, and according to the Diver's Alert Network, increased levels of oxygen can cause will cause a vasal constriction, which increases your blood pressure and reduces your heart rate

and heart output. So I imagine that just means like it's shrinking the blood vessels, right, it's making them tighter. They also point out that increased levels of carbon dioxide, which may accumulate in the body when you exercise during a dive. Uh due to reduced pulmonary ventilation caused by dense gases. This can increase the flow of blood to your brain, which can speed up oxygen toxicity. If you're breathing a hyperoxic gasness mix one with an elevated level

of oxygen. Okay, so would it be normal? I guess that divers would have in their in their breathing apparatus what is it called the tanks or whatever, a mixture that has more oxygen the normal air does. Yeah, yes, I believe. So. I've never been scuba diving, I've I've

only only done snorkeling. On my recent trip to believe, I was around a number of scuba divers and it is I did spend a fair amount of time like sort of thinking about the differences between the people that were there to dive and the people who were there to snorkel and um, you know, and a lot of it does come down to the fact that like snork guing is pretty simple technology. Um and and I love it. You know, you're just you're getting the water and you're

there you don't have to worry about too much. You know, you just make sure you're not brushing up against coral and spit out the salt water when it comes down the snork that sort of thing. But but when you get into two diving, I mean, they're all these careful considerations that have to be made, and you know, I have to keep track of your time and your your bree thing. I mean, it is, uh, it's and it's a whole enterprise. We could we could easily do an

entire episode just on the science of scuba diving. Actually, in one of the books that I recommended in our summer Reading episode last year, The Soul of an Octopus by Sigh Montgomery, there's a there's a whole section in there that's sort of like a memoir of UH learning how to dive with with scuba gear and stuff, because just because of an interest in UH octopuses and cephalopods and wanting to get closer to them and see them in the ocean. And it's it's not as easy as

you would think. It's like an arduous journey, especially when whatever you're diving for at was going to ask you to dive in less than ideal conditions. Uh. Fun fact that trip to believes. Uh, the the place I stayed had a small assortment of books and magazines, like these places tend to do, and that that book The Soul

of an Octopus was was one of them. Oh maybe because they heard our recommendation well or just you know, but probably more than like people that are willing into scuba and diving uh um and and snorkeling, I guess may occasionally bring books of that nature. I'll say it again. If you want to cry about an octopus, read that book.

No joke. Now, we've talked mainly about about humans here and a little bit about octopuses, but plenty of other creatures are adapted to regular jaunts to fairly impressive depths or even of course permanent residency in high pressure waters. So sperm whales for instance, which we've we've covered fairly recently on the show. Um, you know, they can dive

down to depths of seven thousand feet or so. Uh and and uh, this is a really impressive anatomical process that we we talk a little bit about in that episode. But like one of the things that their bodies do is that they their lungs collapse to copes with the

cope with the pressure. Yeah, um, I mean that's actually even so we're about to talk about organisms that live permanently in the deep seas, but the ones like sperm whales that go up and down, like they go all the way to the surface to breathe and then go down seven thousand feet. I mean, what that is something that's especially hard to imagine for you know, without the kind of biological adaptations that they have to sustain it. It's gonna be hard to imagine, especially given stuff we're

about to talk about in just a minute here. Yeah, difficult, difficult for a landsman like like us to imagine for sure. Um. But then of course, yeah, you've got all these deep sea organisms that are permanently adapted to pressure that is that boggles the mind, is just so crushing at the

bottom of the ocean. Yeah. So yeah, deep sea fish that are adapted to high pressures, you know, generally, namely we're talking about like the mere fact that they don't have air pockets inside their body like we do, right, they don't have lungs full of air or more importantly, swim bladders. Yes, uh, there, there's actually like a whole host of of things that come into into play with

with deep water adaptations. Like it's you know, it's easy to sort of like think casually about it and think, well, you know it's a thicker skin or you know, different oregan Uh, but you know, you get into like all of these molecular examples and proteins UM. Deep water organisms for instance, UM, they depend on something that's known as trimethyl amine in oxide, which seems to counter protein destabilizing

effects of pressure. Yeah, that's sometimes known as t m A O. And the problem here is that, as we were saying a minute ago, certain types of molecules that are present in animal bodies anyway, actually become more toxic or more dangerous at greater pressure. And one of those, of course, is the compound of urea, which is in your body. You know, it's important in the renal system. Your kidneys deal with it. But t m AO is a protein stabilizer that helps protect the body against the

toxic effects of urea at high pressure. So if you've got urea in your body, like a lot of deep water sharks do, and they're trying not to make that a poison inside their bodies, that hurts them. The t m AO stabilizes proteins and protects the body against it. But I've also reather this molecule only works to serve in depths. Basically, so extremely deep organisms, you know, many

of which we really don't understand all that well yet. Uh. They have membranes that require extreme pressure, Like they fall apart without that pressure in place. Yeah, totally, though it seems so. It seems that when you are an organism that is adapted to the crushing depth of the bottom of the ocean, how you fare when you were brought into a lower pressure environment. That varies a lot from

organism to organism. I was reading an article by the marine biologist and evolutionary ecologist Craig McClain where he talks about his experiences retrieving organisms for scientific research from the deep sea. You know, they'll put them sometimes in a canister and bring them up with a probe. And specifically he's addressing the question of whether deep sea organisms explode when you bring them up from the lower pressure environment of the surface, and it seems like for most organisms

the answer is no, they don't explode. Though he does talk about his experiences. I think somehow we've mentioned this on the podcast before. His experience is trying to collect a specimen of a particular kind of red sea cucumber, which he says is always reduced to a quote thick red cool aid by the time it reaches the surface. So there may be some kind of explosion scenario going on with this organism in particular, and maybe some others.

But with most deep sea organisms, when you bring them up from the high pressure environment of the deep sea to the surface, there's no pop. The more common immediate danger actually is temperature change. The deep sea is very very cold, around like zero to three degrees celsius usually, or about thirty two to thirty seven and a half degrease fahrenheit, and when an organism is adapted to that temperature, bringing it up to the warm surface can kill it fast.

You know, it might be like boiling it. Though many deep sea organisms can survive if they're quickly moved to some kind of protective cold condition, But the question is how do they survive such an extreme change in pressure coming up from the bottom. And basically McClean says that their adaptations to deep pressure, many of which are sort of biochemical adaptations, having to do with like things happening

at the cell level or enzymes in the body. Those don't happen to be adaptations of a kind that consequently makes them vulnerable to low pressure. It's just like you know, I think he uses the metaphor that if he puts a hat on to protect himself from the sun, that hat doesn't like hurt him when there is no sun. Um. However, these organisms that survived the pressure change from sea floor to surface have usually evolved to possess bodies without major

gas pockets. And that's key. When we're talking about any fish or organism that has a gas pocket inside it, like a swim bladder, all bets are off. Then. Yeah.

I was reading a paper from Ding, Wagner and Popper titled titled the Inner Ear and It's coupling to the swim bladder in the deep sea fish uh Anti Mora rostrata, and they pointed out that they had to pull the specimens up from the deep really slowly because they wanted to try and preserve of the swim the swim bladder the creatures a swim bladder is adapted to deep water pressure, uh that they put it up slowly to avoid damaging it. Yeah, and there's all kinds of interesting stuff out there about

the swim bladder of fish and barrow trauma. You know, pressure related trauma. That's what barrow trauma is. So the swim bladder in fish is this gas filled chamber that allows a fish to essentially well, it allows several things. It allows a fish to rest at a certain depth without sinking and without expending energy to swim, to stay where it is. But it also can help in ascent or descent simply by inflating or deflating the bladder. So it can be a buoyancy stabilizer that helps the fish out.

You don't always have to be pulling your muscles to go where you want to go if you have a swim bladder. But obviously a change in pressure will have an effect on a gas filled bladder inside an animal. It's like if you take a balloon to lower pressure, it expands, right. So what happens when a fish with a swim bladder, especially one adapted to very deep waters with high pressure, gets pulled up to the surface. Well.

A common example can be seen in rock fish. Often, when rock fish are pulled up from the depth, the swim bladder inside its body. Cavity expands to become so large that it pushes the fish's stomach out through its mouth. And this looks almost mind rendingly grotesque, especially since it's often accompanied by Ronnie Cox in Total Recalls style bulging eyes. I've got some images for us here, and literally the stomach is just poking out of the fish's mouth. It

looks like a huge tongue. It does. It looks like a big cartoonish tongue or level or at least the end of a sausage. And it's because the swim bladder has been so inflated by the low pressure environment. It's just like pushing out against all the other organs and the stomach escapes that that pressure of the swim bladder through the mouth, so it's it's averted. This is like pocket on your jeans pulled out inside out. Yes, there's something swelling up inside the fish because of the low pressure.

It's that gas chamber and it's like pushing the guts out through the mouth. It's so gross. Uh. And obviously this can be traumatic and can kill the fish. But actually I was reading fish can sometimes survive this low pressure barrow trauma and UH and even survived the gut a version if quickly returned to their native native depth. This can be difficult though, because sometimes the gas distension here causes them to float and be unable to sink

back down. But I've read that you can sometimes safely get them back down to depth just by like covering them with a weighted upside down milk crate on a line, which is then lowered back down to depth until the fish swims away on its own. But it sounds like a little extra work. But really, I mean, if you've if you've pulled the fish out of its natural habitat, you know it's it's it's the decent thing to do to either I guess eat it or put it back

where it came from. Well, yeah, I mean it makes me think about there's this whole concept of catch and release fishing. You know, people do catching release, which is one thing if you're catching a bass in a lake, you know you not necessarily going to kill the fish if you catch it and then you take the hook out and you throw it back in. But with the you know, with a fish like this, if you pull it up and it's guts, get averted by the by

the pressure change. Its stomach is sticking out, its mouth, its eyes are popping out, and then you just take it off the hook and throw it back in the water, and then it just floats on the surface and dies. I mean, what's the what's the purpose of release? Then? Yeah, exactly. Now, of course, again there's there's a lot more to the evolution of DC organisms. You know, it involves a number

of evolutionary adaptations and involving tissues, membranes, proteins, etcetera. Like I said, Uh, And to come back to explosive decompression for a second, which is, you know, a matter all on its own. Uh. You know, this generally occurs when you have a rapid change in pressure, generally going from something like nine a t M to one a t M instantly. And these sorts of events occur due to malfunctions and closed systems. So we're talking about human technology here.

There are a lot of misconceptions and myths about this sort of thing as well. But um, the the fatale by for dolphin diving bell accident is a frequently cited example of this sort of malfunction and the like the fatal nature of it like just really, how how destructive that can be to be a living organism exposed to

such a drastic change. Yes, though it is. I would say there are a lot of myths out there about explosion in low pressure environments, Like the whole idea that you would explode if exposed to the void of empty space. That's not generally believed to be true. Uh you know, if you were exposed to the void of empty space, I mean, it would kill you, but not by making

you explode. All right, Well, on that note, we're going to take another break, and when we come back, we're gonna talk a little bit about geologic pressure and pressure on other worlds. Thank alright, we're back. So we've we've discussed geologic pressure rather recently on the show, talking about tunnels and digging in the Earth and what's the deepest we've tunneled, and what's the what what is the depth

the greatest depth that we've descended to. And so just to reiterate, geologists calculate that for every mile you dig down, the temperature rises fifteen degrees fahrenheit and the pressure increases at a rate of seven thousand, three hundred pounds per square inch go down deep enough and the temperature and pressure is enough to form diamonds. Uh. Now that the

specifics of diamond formation. This is also something you know, we could easily devote an entire episode two, But I want to just read this quick bit from How Diamonds Work by Kevin Bonser on how stuff Works. I wrote a number of articles for that website back in the day, and and may still be for all I know. But

here's the quote. Quote. Diamonds form about a hundred miles a hundred sixty one kilometers below the Earth's surface in the molten rock of the Earth's mantle, which provides the right amounts of pressure and heat to transform carbon into diamond.

In order for a diamond to be created, carbon must be placed at least four hundred and thirty five thousand, one hundred and thirteen pounds per square inch or a p s i or thirty kilo bars of pressure at a temperature of at least seven two degrees fahrenheit or four hundred degrees celsius. So four hundred and thirty five thousand pounds per square inch. Yeah, it's hard to imagine

pressure like that. I mean, this is unfortunately one of those cases where I think we can say the numbers, but there's nothing you can compare it to, right, There's no kind of you can't oh, okay, this was what it would feel like. You know, you just don't have a sensation based point of comparison for that kind of pressure. Yeah.

And now if we're talking about the core of the Earth, that's that's also crazy, because we're talking about a solid iron ball about one thousand, five hundred miles or kilometers in diameter. It's white hot, but the pressure is so high that the iron cannot melt um. And the temperature is probably between nine thousand and thirteen thousand degrees fahrenheit or five thousand and seven thousand degrees celsius. And as

for the pressure, it's I've seen it list. I think there's a National Geographic dot com article about the Earth's interior. The pressure here would be somewhere between three hundred thirty and three hundred sixty giga pascal's giga pascals or um. That would also be uh three million, three hundred thousand, or somewhere between three million, three hundred thousand and three million, six hundred thousand a t m s. But again we're talking,

we're talking numbers like this. It just gets impossible to really put that in anything approaching a human frame of reference. Yeah, you can't really like picture or imagine it. You just have to say, well, I mean, I guess boy. Human bodies don't go there, and if if they did, they would just you'd just be I don't even know what the word is. I'm trying to saying crushed would be one thing, but it would be more than being crushed, because that's normally like uh, you know, being pressed down

into a small space. I would think more than just obliterate, obliterate, annihilated, it would be It reminds me a little bit of the In the past, we've talked about different health theologies about what if if there's a hell in your uh, your your your religious worldview, what happens when you go there? And in some of them it's you know, it's like, oh, there's fire and somebody's sticking you with something. But in others, it's total annihilation, like your being, your soul, everything is

just destroyed. And if you really were to go to the center of the earth after you died in a kind of like physical direct fashion, I think annihilation theology would hold pretty sound. Maybe, yeah, what's the that's a good point. Yeah, Or maybe you'd only I guess your best hope to send only far enough. You would just be crushed into a diamond. Has anyone ever been crushed into a diamond in like a comic? I think Superman

could make diamonds. I believe there is a service. I don't remember if this is real or not, but I think there's a service that at least claims that they will turn your dead your dead body into a diamond. Take your ashes, and take the carbon content of your body and squeeze it down and to a synthetic diamond. Ah. Yes, yes, that does ring a bell. But it's not like Fantos Thanos doing it with his his his gauntlet or something. I don't know. I gotta admit I don't know anything

about Thanos. What does Thanos do? He's got the big the gauntlet with Okay, I haven't seen those movies, so I don't know about than I'm sorry. Well, he is from another world, so let's talk about other worlds. A planetary examples of extreme pressure. Well, yeah, that's kind of interesting because I was thinking about how when you imagine crushing environments and other planets. I think most of us, if you just think about it real fast, you probably

think first of gravity. Right. We imagine there's some planets out there in our Solar System so huge and massive that their gravity would make it impossible for us to walk around on their surface, would be crushed under the weight of our own bodies. Yeah. I always go back to phantasm. Yeah, and I think of the how they right phantasm, Yes, how they were crunching down the corpses into these like Java like dwarves, presumably to serve as like slave labor on this massive world somewhere. This is

the rich imagination of Don Costcareliott a Jawa universe. But yeah, so within our Solar System at least, it's not really the gravity. I think you'd have to worry about the most in terms of being crushed on other planets that we can. So we can estimate some of the effects of high gravity planets simply by looking at the effects

of acceleration on test pilots. Uh. The the effects of gravity and acceleration are physically actually the same, and this is why we measure the force of acceleration on the human body in terms of G s. One G is one Earth gravity at the surface. Yeah, if you think back to our episodes on artificial gravity and the ideas about how to generate artificial gravity and space, we get into this affair amount. Yeah, you use acceleration angular momentum.

U use acceleration in space to simulate G forces and of course heightened G forces. So gravity and acceleration alike or negative G forces, these can harm or kill humans. That's certainly true. Primarily, I think, uh, the first thing that would kill you would be their effects on blood flow, like by pushing blood from one part of the body to the other, preventing circulation and say preventing oxygen from reaching the brain, or preventing blood from getting out of

the brain. But unless I'm mistaken, I think there are no planets you could stand on in our Solar system with enough G forces to kill you, at least not immediately though. I mean there'll be lots of other things to kill you radiation and lack of breathable oxygen and all that, But the G the G forces alone, I don't think would crush you anywhere in our Solar system. Yeah. I was looking around about this a little bit and it.

For instance, um, the estimated cloud top gravity of Jupiter would be something like two point five to eight g's, so they're not a drastic increase. That's something test pilots can they do when they survive. Yeah. Now the surface of the Sun, however, that would be a gravity The figure I've found for that was twin seven s. Okay, So if we're gonna go walk in on the Sun, that would be a problem, a problem, But there are places you can go on our solar system, or atmosphere

pressure would pretty much instantly annihilate you. I think Venus is a great example. Venus is really similar to Earth in mass and size. It's gravity is just a little over likee of Earth's, probably due to runaway greenhouse effect. Though, the atmosphere of Venus is super dense, composed mostly of carbon dioxide, which traps heat, making Venus beyond boiling hot as well. Now, remember, on Earth, the atmosphere presses on us with about fourteen point five pounds per square inch.

The pressure on Venus is about ninety two times that, or roughly equivalent to the pressure at more than nine meters or three thousand feet below the surface of the ocean absolutely crushing just to stand on the ground under the atmosphere in Venus, and I've seen it described that just the air, it would be kind of like being in a liquid. I mean, it would provide resistance when you tried to move because of how dnse the carbon

dioxide atmosphere is. I mean, I think about the probes that we've actually landed on Venus in the past, you know, the Soviet manera landers and stuff. They were they had short lives. They got down to the surface and did manage to send back a few kind of grainy images, but they do not live long. Like once you're on the surface of Venus, it's hot enough to melt lead. As commonly said, it's like ninety two times surface atmospheric

pressure on Earth. It's it's not friendly. Of course, the exact opposite is true of Mars, which has an atmosphere somewhere around a hundred times thinner than Earth's atmosphere, which means it weighs very little and pressure is very low. You don't want to go on the surface of Mars without your pressure I spacesuit on otherwise you might I don't think your guts would get inverted you would, you would have serious pressure based problems, low pressure based problems

in addition to not being able to breathe and all that. Strangely, while freezing and lacking oxygen, Saturn's moon tighten, I think, compared to these other options, would have a relatively cozy atmosphere pressure of only about sixty percent greater than Earth's. According to NASA, it's roughly equivalent to swimming in about

fifteen meters underwater. I mean, that's not the most comfy, but that's you know, better than venus, better than ye And interesting difference with the atmosphere of Titan is that because the gravity of Titan is much weaker than Earth, so I think it's only like fourteen percent of Earth's gravity, the atmosphere is held much more loosely and extends much higher into space. The sky literally goes higher on Titan. Now Earth's atmosphere, as we've discussed earlier, it's hard to

say exactly where it cuts off. It just gets thinner and thinner as it goes higher and higher, much like Titans would also. So there is no clear dividing line, but a hundred kilometers is often cited as the beginning of space. That's just sort of an arbitrary marker that we use. I'd love to see what the sky looks like from the surface of Titan during a sunrise, during

a sunset. I kind of want to go there with an atmosphere that is, you know, very roughly six times thicker than though I've a given different estimates I've seen. It also is said to be like ten times. Thinker, it's just six to ten time. I mean, just goes up and up and up. It would seem like it never stopped. But one last question, I was wondering about going back to our thing about about the possibilities of

pressure having an effect on mountaintop religious beliefs. If different atmospheric environments and the differences in pressure do actually have anything to do with religious beliefs about mountains, Could the differing pressure of other planets do the same, Like what a low pressure or high pressure moon or planetary outpust become Olympus or Kailassa or some other kind of holy mountain in space. I think we should come back to

doing the Sacred Mountain episode. I'm I'm stuck on that now. Well, there's yeah, there is a lot to discuss because I mean there's so many different of course myths and religious models that there's specifically interesting. I know, in the past we looked into the possibility of doing an episode about monsters of the mountains. Yeah, and uh, you know, we did a little looking around in that in that area. So yeah, I'm always happy to return to the mountains.

We haven't given the mountains enough attention. Really. We can climb every mountain on the moon. There you go and find the dish that ran away with the spoon, all right, So there you have it. Pressure, uh, you know, just hopefully just a nice exploration of atmospheric pressure. Um, push us down on me, push us down on you. Yeah, under pressure. Just a nice overview of pressure to be found on Earth, in Earth and on other planets. As always,

we'd love to hear from you your thoughts on this episode. Um. Uh. Certainly other like cool scientific uses of pressure pressure differentials out there that would be fun to discuss. Uh. We we love hearing from folks about all of that. And hey, if you want to learn more about our show, heading over to Stuff to Blow your Mind dot com. That's

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