Their fur is very dense, otter fur has more hairs per square inch than any other mammal, a million per square inch, like a hundred times what humans have. The oils excreted into their fur creates a hydrophobic layer that keeps the water on the outside. It's in nowhere near shark skin (which exhibits incredibe hydrodynamics, like we're studying it in labs to better improve aerodynamics of cars and planes, a single bite of food is enough to get a great white shark from California to Japan their skin is so efficient at moving through water), but it's very good at keeping the water out and their movement efficient, their hair does not cause Resistance like human hair does. Our hair hangs out and gets water in it and creates drag, otter hair seals itself around the meat and creates a cylinder, keeping happy warm dry otter inside.
I got the treat of touching/petting a wild otter while it was sedated, it's on of my top 10 experiences. It was not a happy camper when it woke up. It had to be in an ice bath while sedated otherwise it's hair/fur coat would've caused it to overheat while being knocked out because it is incapable of homeostatic regulation while sedated. When it woke up it was a wild otter in an ice bath, lil (haha, huge actually) dude was pissed.
Huh, thanks for the detailed reply! I suspected some of them must have something extra going on to help their time in the water, but wouldn't have thought this!
Were you able to feel how dry the otter was through the sealed fur, or was it sealed enough that you couldn't really tell?
I've never felt one under water, nor did I try to go skin deep when I had my opportunity, but I would guess they're pretty dry under there, I couldn't say for sure though.
Under normal circumstances; you feel feedback from your actions. Kick something, and you’ll immediately, before you’ve finished applying force, feel pain in your foot. That pain causes you to reduce the amount of force you’re applying, both to end the pain and to prevent damage. This is an automatic subconscious reaction.
Add in a shot of a adrenaline though, and that pain feedback is heavily subdued. Your brain doesn’t register the signal to pullback, so you follow through with more force than you otherwise would be able to before self preservation kicks in.
the messed up thing about getting old is that you can start hurting yourself doing things that used to be “easy”. like lifting heavy weight or gripping something tight (like opening a jar). all of a sudden it feels like your muscles are breaking your joints and damaging your tendons/ligaments. its the muscle memory that gets you into trouble. good times, good times.
It really is. I once broke my foot running up some stairs. It was an emergency and as I was running I caught the edge of one step with just two toes(I did have shoes on) the ball of foot missed the stairs completely. Instead of slowing down or trying again I just pushed hard throwing my weight forward. Find out later that I had a radial fracture of my second metatarsal. The crazy thing is I spent the next few hours walking on a broken foot and didn’t feel it at all.
I did feel it the next day though. Fuck that hurt .
It probably wouldn’t make any difference in the appearance of the belly button, because eventually it work dry up and fall off, just like if you were to clamp and cut it. There are definite benefits to delaying the clamping of the cord. There is a lot of blood in the cord and placenta that is lost that could be auto transfused to the baby if the cord is left intact.
The main problem with leaving the cord and placenta intact is that there is a risk for infection or blood loss. Also it would look really gross in the baby pictures.
Your body IS being constantly pressurized by the atmosphere, and your various sphincters are used to that. Presuming the suit doesn’t pressurize your body beyond what it’s used to (at which point breathing would be difficult), there should be no unexpected anal excretions due to the suit.
But the pressure from the atmosphere applies to both sides of the sphincter, resulting in zero net pressure. Unless the suit actually does press against the outside of the sphincter like it does the rest of the body, I think OP’s concern about the suit squeezing you like a tube of toothpaste is valid.
Maybe the suit only applies a few PSI instead of the full 14.7, which it seems like one’s sphincters would be able to withstand.
I think it’s like a third of an atmosphere or something. Enough to comfortably achieve the same partial pressure of oxygen as normal Earth air, by providing it pure.
No. Unless that hot water is very, very hot vapor, you’re just adding more mass that’s going to be cooled by the original cold water. And even with vapor, the heat transfer between a hot gas and cool liquid just doesn’t happen fast enough, the vapor will be in the atmosphere before the water heats up very much.
I don’t see how anything non-Newtonian would be better against sudden sounds. In fact it would be worse, as they’d get more solid and thereby transmit MORE of the noise you’re trying to block out. Or maybe they only get more rigid but their sound transmission properties don’t change at all. Either way, sounds somewhat pointless.
The only way I can think that something like this would work would be to have a molded vacuum chamber as an ear plug, with a specifically engineered sound transmission bridge inside. With too much energy trying to go through, it would break. But I doubt it would be quick enough to be effective, and they’d also be one time use, and extremely fragile.
It’s a bit oversimplified, actually. Sound bounces off of discontinuities in the medium, which is why foam works. You just have to control scattering somehow.
The big problem with using oobleck or whatever is it responds to shear, and shear can’t travel through air. You could use it for earthquake protection, though, or if you could channel compressive waves from the air into shear form using a fancy bridge like in OP.
There are lots of strange options besides newtonian fluids. Would be interesting to see how dilatant, peusdoplastic, thixotropic etc react to sounds. Perhaps there is a way to make a material that allows quiet sounds to pass through and blocks all the loud ones. My guess is that dilatant liquids should be a good candidate.
A quick search tells me this have to do with shear forces. Sound would be entirely compressive, so those material properties would have no effect, or at least not change due to sound levels.
That’s unfortunate. Just like OP, I would have really liked the idea of using a non-newtonian fluid to filter out certain types of sounds without using electricity. Well, I guess, we’re back to active noise canceling then.
"Full darkness" isn't even a real thing in nature. It's hard to tell with light pollution, but even in the absolute middle of nowhere with no artificial lights, you're going to be able to see fairly well. Even with no moon, starlight isn't just an expression. And on a full moon it can be surprisingly "bright" if you're just out there for a while.
It's not like climbing into a cupboard, shutting the door, and sealing all the cracks with duct tape.
You may be used to needi g full darkness to sleep, but that's a learned habit. I guarantee if there was nothing you could do, it wouldn't take you long to adapt your "requirement" of total darkness.
but even in the absolute middle of nowhere with no artificial lights, you’re going to be able to see fairly well.
I'm not sure I'd say fairly well. Maybe always well enough to not walk directly into a tree in otherwise open terrain. A full moon will be comfortable to walk around in, but new moons happen just as often, and sometimes the moon is below the horizon.
Source: Have walked around in the country at night.
I mean, my night vision was always better than most...
But growing up as kids we'd be sprinting thru the woods playing tag at like 10pm summer nights, not a single electric light in sight
You're not going to recognize someone 100 yards away, but you're not walking around with your hands in front of your face to make sure you don't run into anything.
If you're under an open sky, or even a primitive shelter, you're not in complete darkness.
Hmm. Are we talking a high canopy, and fairly level ground? I feel like I'd definitely break an ankle if I tried sprinting otherwise.
I never had too much trouble, but sometimes things hiding in tall grass would surprise me, and in heavily treed patches I'd occasionally hit a low branch I didn't notice.
I also have to account for the fact that there was some light pollution, and I could always see skyglow from towns in the distance. I doubt land ever gets close, prehistoric or not, but in the darkest conditions that happen at sea apparently you can't see your own hands.
I feel like I’d definitely break an ankle if I tried sprinting otherwise
Yeah, we played paintball even, but stopped because one guy ran straight off like a 6 foot mini cliff. A couple of us were chasing him and he just disappeared. Was freaky as shit like that scene from LotRs.
I also have to account for the fact that there was some light pollution
Yeah, I'm talking really hillbilly stuff, zero light pollution.
but in the darkest conditions that happen at sea apparently you can’t see your own hands.
A ship gives off a lot of light pollution, but even without that, between the water reflecting and nothing blocking light, it's brighter out there unless there's heavy clouds cover. And even then it's gotta be a lot of clouds and rough waves or else the light would still be refracting some.
Now a watertight compartment on a ship with the light switch on the outside?
Yeah, that's complete darkness. It's not just "can't see your hand in front of your face". It's the absolute and complete absence of light. That's total darkness.
Yeah, we played paintball even, but stopped because one guy ran straight off like a 6 foot mini cliff. A couple of us were chasing him and he just disappeared. Was freaky as shit like that scene from LotRs.
Lol, yup, that sounds right. I did that once, although it was only like 3 or 4 feet, and I didn't like it one bit. Is was a sinkhole or something too, because it was cliff all around, and I had to find a spot to climb out. I didn't visit that area again.
I forget where I heard about the sailing thing now. That would be a 1 on the Bortle dark sky scale, though.
i found i did indeed need to have hands out because i can’t see much at all in deep country at night on a new moon. maybe i just don’t have great night vision.
That's why there's "blue light filters" on electronics these days. That wavelength isnt included with moonlight/starlight.. maybe on a big full moon there's be some.
And why people prefer soft yellowish lights when relaxing and not the bright ass LEDs.
Full darkness is most certainly a thing and is more of a thing then light..light is artificial. Remove the sun...what do you get, full darkness. Light is added, darkness isn't.
Same with heat..everything is cold unless heat is added.
Cold and full dark are forever, heat and light are techcially temporary.
“Full darkness” isn’t even a real thing in nature.
And
It’s not like climbing into a cupboard, shutting the door, and sealing all the cracks with duct tape.
So I thought it was pretty clear I meant that to get "full darkness" where you really can't see, requires extra steps to intentionally make it happen. Just that for the vast majority of human evolution, we weren't really capable of it, and would have no reason to even try.
The experience of people working the night shift, who use blackout curtains to sleep during the day, would disagree.
But that's for a relatively highly regimented sleep cycle. If you slept and worked completely at your leisure, you might end up with one shorter sleep period at night, and one even shorter nap during the day. And without any day-night cycle at all, some people naturally adopt cycles of varying lengths.
The experience of people working the night shift, who use blackout curtains to sleep during the day, would disagree.
Wow, I didn't know my own experience disagreed with me...
Or that during my childhood when my dad was swing shift, he was apparently a freak of nature too...
But that’s for a relatively highly regimented sleep cycle. If you slept and worked completely at your leisure, you might end up with one shorter sleep period at night, and one even shorter nap during the day. And without any day-night cycle at all, some people naturally adopt cycles of varying lengths.
Again, human variation is a big thing.
But an individual will change their sleep schedule as they age, which is another supporting point for what I'm saying.
Evolutionary biologists hypothesis that it was so out of an entire tribe of early hominds, at least some members were likely to be awake. It wasn't an inate guard duty rotation. But kids and middle age went to bed early, teens went to bed super late, and by then the elderly were waking up.
If something happened, someone screamed and everyone woke up. And the fires stayed lit all night.
This is untrue - we have explicitly evolved to sleep in the dark. Sleeping in the light is a learned behavior that's more or less an exploitation of a loophole in the circadian clock
The intensity and the wavelength of light influence entrainment.[2] Dim light can affect entrainment relative to darkness.[15] Brighter light is more effective than dim light.[12] In humans, a lower intensity short wavelength (blue/violet) light appears to be equally effective as a higher intensity of white light.[11]
Yes, but your wikipedia link doesn't prove that animals are only sensitive to blue light, only that they are more sensitive to blue light. That is a very well-documented phenomenon. But there is plenty of evidence that red light can entrain circadian rhythms as well, dating well back to the 80's. There has even been a study that identified different mechanisms of entrainment to low-wavelength and high-wavelength light in bacteria, which you can find below. My point is that it is very scientifically irresponsible, and in fact, blatantly wrong, to claim that humans are sensitive only to particular wavelengths of light, when in fact humans and other animals are sensitive to all wavelengths of visible light.
Beyond that, I don't necessarily know why you seem to be claiming that the intensity of the ambient light does not matter for photic entrainment, when this is a highly documented and, in fact, highly studied phenomenon in the circadian field. Yes, the moon reflects light, but this is dim enough that mammalian SCN's can interpret the difference between that and the full daylight. See below for some papers that look into light intensity and their effects on entrainment.
Generally in trees you have the xylem in the middle which transports water and minerals from the roots to the rest of the plant. You have the phloem on the outside, it transports photosynthetic products and nutrients to all parts of the plant. The cambium where growth happens sits between them, because there they get easy access to water minerals and nutrients. The xylem is a mix of living and dead cells. The tracheids and vessel elements in the xylem, which are responsible for water transport, are dead at maturity. So it’s probably too hard to move them to grow from the inside out for trees. This whole process of growing thicker is called secondary growth as opposed to primary growth at the tips of stems and roots.
Also if were the other way around and trees would grow from the inside out, you’d have to have vessels going from the leaves to the center of the stems to deliver nutrients, which just complicates everything. And the tree wanted to grow from the inside by 1cm, every “ring” in the xylem would have to grow one centimeter longer in circumference or crack. It’s much easier to just add a layer on the outside. Also having living layer around the tree probably helps it defend itself from pathogens. If all the mostly dead woody stuff was on the outside fungi etc would have an easier time invading, I think.
I think the phrase down the rabbit hole is actually referring to Alice in Wonderland. But.
I would say the organism that tends to burrow the deepest into the Earth is humans. Average oil well depth appears to be around 5,964 feet (1818 meters), that’s pretty deep. The deepest hole we ever drilled is supposedly the Kola Superdeep Borehole dug by the Soviets, it was 40,230 feet (12.2km) deep.
Oh, that’s a fair point on both counts, I should have specified non-human organisms. Still, we’re apparently really good at digging deep holes, so that’s fun!
Ngl I have mixed aqua regia to clean out my pestle and mortar in a lab course once. Shit went from uncleanable to clean really quick. H_2O_2 + conc. HCl is sufficient for most extreme cleaning needs tho.
That makes sense, thanks, since our threshold for co2 is less than 0.5%.
I may have worded my question poorly; I’m more asking why low oxygen is a problem vs low nitrogen. In retrospect, my climate focus may be distracting. It was what made me wonder about this in the first place, but the medical and scuba points are much more relevant. That has little to do with co2 (I think?) and more to do with the relative compounds in our air.
I’m still confused why we hear about oxygen but never nitrogen. Another example: when we look for habitable planets, the focus is ‘oxygen rich atmosphere’, but not ‘nitrogen rich’.
Maybe nitrogen could be replaced with other gases, but we need oxygen in our lungs and bloodstream to survive. So maybe it’s more important for our survival?
So from what I understand, we need a rather precise amount of oxygen plus a large amount of an inert gas – pretty much any inert gas, barring a few that have narcotic effects. So nitrogen isn’t special, except that it’s inert and doesn’t get us high.
But I’m also curious whether the reactive gas in low quantities (oxygen) can also be replaced. I’m not a chemist, and this is fascinating. I’ll keep reading.
I’m not a biologist, doctor, or chemist, but my guess is “no.” We have evolved to use oxygen to create energy within our cells, not some other gas.
I would hazard an additional guess that it’s not a simple matter to just swap out the oxygen molecules for something else. Carbon monoxide binds better and more readily to our cells, yet that mixture would asphyxiate you.
We don’t need a precise amount of oxygen - we can survive in a fairly wide range. Think about living in the mountains vs by the ocean.
Nitrogen gets us absolutely high. Balls to the wall high. It’s why gas narcosis used to be called nitrogen narcosis. Also known as the “rapture of the deep”.
Also, oxygen gets you high. Also, oxygen kills you, but that’s another matter.
As someone else pointed out, nitrogen is non-reactive. Almost any gas would work, as long as it was plentiful enough to maintain the necessary air pressure, and non-reactive. You don’t need nitrogen to live; you just need oxygen. Just, not so much that you get acute oxygen toxicity, which mainly happens with pure oxygen at regular atmospheric pressure for extended periods of time. There are even applications where pure oxygen is administered to people, usually at lower than atmospheric pressure.
Nitrogen is a filler gas. It’s there to take up space and keep the air molecules bouncing around at the appropriate pressure. (Or perhaps it would be more accurate to say our lungs require a certain pressure because this is where we evolved; that pressure happens to be maintained mostly by nitrogen.)
We aren’t exploring other planets in person yet, but if we were, we’d need to filter out all the bad shit in the air, keep the oxygen, and maintain the normal pressure. If we were lucky enough to encounter an atmosphere with oxygen, a non-reactive filler gas, and no toxins, we might be able to just breathe it; or to breathe it after compressing it to the appropriate pressure. Nitrogen wouldn’t need to be there at all.
The confusing thing about the scuba application is that nitrogen isn’t in the mix because you need the nitrogen. It’s there because it reduces the pressure of toxic gases to a threshhold you can survive.
Thank you for your detailed response. That explains things very well. I don’t know a lot about chemistry, but is oxygen specifically required for cell metabolism or could that be replaced with a similarly reactive gas, too?
We’re pretty hyper-specialized to use it, but there are organisms on earth that don’t need it and in fact find oxygen deadly; they are called anaerobic. They still need chemical energy, it’s just not provided by oxygen. (As I was looking this up I discovered there’s even a creature in the animal kingdom that doesn’t breathe oxygen.) Some gases, like carbon monoxide, will actually participate in gas exchange in your lungs and react with your body chemistry, but in a way that rapidly breaks down cell functioning.
So, yes, there are definitely other forms of biochemistry that can process non-oxygenated environments and extract energy from them, just not us, not by a long shot.
There is a fan running and then the actual microwave itself. If you lower the power setting, you can hear the fan stay on consistently but hear the microwave shut off and on. If the power is at 100%, the microwave runs the entire time.
A few microwaves don’t do that because they’re able to continuously run the magnetron at less than full power by using an inverter instead of a transformer.
A good rule of thumb is that the energy needs to go somewhere. So if the adapter was drawing a significant amount of power, it would get warm to the touch.
That’s true - And with a halfway decent thermal camera, you can see most of these unused chargers as “hot” spots. They’re so low power that they’re only slightly above ambient, but still something the cameras can see.
That’s how I found out that my desktop speakers consume power even with the physical button being off and status light dark. The power brick stays warm indefinitely, a good 20W feels like! I have to unplug that thing now when not in use. Any normal power brick will be <1W of course.
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