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Consequences of sudden exposure to very low temperatures
nyckelpigor wrote in little_details
And by "very low temperatures" i mean something akin to being lowered feet-first into a vat of liquid hydrogen over the course of several minutes.What would be the consequences? How would the victim feel? How far in would he make it before he dies? How would the body end up looking like?

All my search terms resulted in lots of information on hypothermia, but I imagine that my situation should have very different conseuqences from obvious reasons.

have you run google searches on frostbite? because at such temperatures the cells in the feet being dipped into such a cold liquid would freeze very quickly i would think.

I don't know how helpful this will be, but I heard an interview with a scientist with both academic and personal interest in cold. One time he tried getting in very cold water (IIRC he broke ice on a lake in winter or something like that) --- and made sure to have a friend close by, because he know that after about 5 minutes, the cold would make him pass out.

So if that's typical, your character would probably lose consciousness pretty quickly.

That's actually fairly common in Sweden - to get into a hole in the ice or something similar. My father does it regularly. It's quite refreshing.

However, you don't stay in for very long.


Idle curiosity made me google liquid hydrogen and apparently you have to have it in a pressurized, insulated container to maintain its liquid state, so it's possible you wouldn't be able to even *do* that, unless the whole room is that, in which case would the pressure maintained have effects first? Like - person suspended in room, pressure achieved to maintain liquid, person dies as if you just shoved down into an abyssal trench....

Anyway, that aside, i would imagine that severe frostbite is your best bet for what it would do to the body (freezing kind of explodes liquid things, so...yeah....) and i imagine that, pressurized chamber aside, the person would be in agony and then unconscious fairly quickly.

Google what severe frostbite looks like, if you can stomach it, for what it would do. Although maybe x100.

they said 'like' liquid hydrogen. so not actually liquid hydrogen. you could do that in a sci fi setting through with some kind of containment field that pressurises the hydrogen and keeps it liquid but that you can dip people through. i mean, you can write any such thing in sci fi and people will believe it because of shows like Star Trek.

and yeah, frostbite is where my mind went too. they might also get so cold that they would fall unconscious, good point.

ETA: you don't need to pressurise hydrogen to make it liquid, that's just so that you don't have to reach very low temperatures, because that can be very hard to do. so actually, in a sci fi setting you can just have the liquid hydrogen in some kind of swimming pool that is cooled and kept at a something like 10 Kelvin, maybe with a helium cooling system, that's how we keep our cryo pump that cold. granted it's a small pump and not exactly the same scale as cooling a swimming pool full of liquid hydrogen, but in sci fi, you could run with that...

Edited at 2012-11-11 04:35 pm (UTC)

That's true. I didn't really think about sci-fi, since it didn't come across to me as a sci-fi scenario, but hey - everything's better in spaaaaaaaaace!


Dude - Star Trek is ALL TRUE. C'mon.

every damned word!

they recently made a tractor beam that could pick up stuff like space dust i hear... space dust/space ships... same thing, right?

Edited at 2012-11-11 04:42 pm (UTC)

I think I remember something about the anti-matter stuff. It's quite cool that it's advanced so much that it seems feasible (in the future some time). I remember when I was proof-reading a report my partner wrote on possibilities for fast space travel back in 2006 it was all about solar sails...

Solar sails are also awesome.

I think the whole 'live to be 150!! thing is kind of stupid, usually, but i would do that if it meant i could, some time, actually *go out into space*. I get horrible motion sickness and would fail utterly at any kind of astronaut training, but my gods.....

I wish i could just go up, and out, just the once.

hehe, lol, just talked about that with my partner yesterday. he just had to take a flight somewhere and afterwards called me and said: "screw ever going into space. i can hardly deal with flying on planes! even if it becomes an option, i am NEVER going into space!"


i would. lol. sadly i'm the wrong nationality so i will never be an astronaut unless international science politics changes very quickly, which is unlikely. if it ever does, i will be too old, lol.

Dude, i haven't flown in years, but the last time i did, i pretty much wished for death. Gods, i hate it. But i'd take drugs and do about anything to get up into space..... :)

I guess i'm ignorant in such matters - why would your nationality preclude you from being an astronaut? I know not a lot of countries have a space program, but surely you could do it, anyway, though it might mean becoming a citizen of another country....

I know, not necessarily something you'd want to do, but - educate me on this point, please?

actually yeah, if i changed my nationality then that would work. XD

it's political. if your country doesn't contribute to the European space programme, then technically nothing stops you applying. you are very free to apply anyway, as long as you have the qualifications. But realistically you have a 0% chance if your country is not one that contributes to the space programme. after all, part of the 'reward' of investing in the space programme is, sadly, not science but having astronauts from your country up there in space.

that's ESA for you.

NASA are a lot better, actually. But i don't have dual American citizenship, which would be required. The only person from my nationality without a dual nationality went up with funding from the USSR... i missed the USSR funding boat by a couple of decade, me thinks.

Guess I should get packing for America though or for ESA, maybe I should learn French? I already know German. Maybe I could do that... :P .

And hey, space tourism might be in the future and that would be super cool while high on drugs i think! "Woah man, the earth... looks like a mouldy bad cupcake. I want to eat it, dude..."

Ah ha. I see. That's a bummer.

I long for space tourism! C'mon, science-guys - hurry up and figure it out!!

i think we have the science, we just need the money... come on 1% people. give all your money to a space project. you know you wanna...

Yeah, c'mon!! If you have more than five million, you can spare a million!

I wish I could be an astronaut, but sadly i am both too short, and too blind xD all these pesky little details that break your heart, like astigmatism and nationality :D

My eyes at least would be game for it all. I am not sure I would pass all the health checks though, tbf. ;)

apparently you have to have it in a pressurized, insulated container to maintain its liquid state

At atmospheric pressure it boils at 20 K, about 50 K (50 degrees C) less than liquid nitrogen and 16 K warmer than liquid helium, so it's not impossible to have a container of it sitting out at room temperature. Unlike these gases though, the hydrogen gas needs to be collected as it boils or else whatever room it's in will become a very explosive hydrogen-air mixture. For these reasons cyrogenic hydrogen is fairly rare compared to these other gases, and only used when some physical property of the hydrogen (flammability, nuclear density) is desired, rather than simply its boiling point.

Ooh, interesting. Thanks!

I suggest running google search on dangers (or hazards) of hydrogen.

Liquid hydrogen tends to freeze flesh solid and then shatter if hit. Whatever part of the person was submerged would be dead almost instantly. More concerning for your character's lifespan is the fact that people tend to have a heart attack when exposed to cold temps, even as relatively warm as cold water. Google Cold Shock Response. I can only imagine that it would be faster/more likely with even colder temps.

Also if the TV show Bones is to be believed if you liquid nitrogen a turkey then drop it off a balcony it doesn't shatter but bounces. So your victim might not go entirely to pieces if you don't want him to.

the freeze and shatter thing would depend if it freezes fully, which will depend on the time submerged. like, when you put something in the freezer it can some times take forever for the centre to freeze. should all go a lot faster with such cold temperatures though! i'm not sure if anyone has ever tried it though and sadly how fast something freezes isn't something you can just pull some physics formula out of a book for, because it depends on so many different variable as liquids and crystals are involved. i'm sure if they just talk about everything visible on the outside like all the skin etc having died, that would definitely be very plausible after a few minutes.

Liquid hydrogen tends to freeze flesh solid and then shatter if hit.

That has not been my experience. All the connective tissue in flesh is not subject to temperature-induced embrittlement. Even the most freezerburned steak is not going to shatter into pieces if you smash it with a hammer, and taking it down all the way to cryogenic temperatures doesn't change this. If this were not the case, you couldn't flash-freeze foods, because they'd be too fragile to handle.

Embrittlement happens mostly to rubbers and plastics - materials that do not break easily because they have some elastic properties due to being handled at temperatures well above glass transition. Cooling them to very low temperatures makes the stretchy parts like glass, which makes them easy to crack, and allows these cracks to propagate through the material easily.

The main consequence of being lowered into something like that would be nearly immediate death, followed by eventual thawing and decomposition.

Anything involving hypothermia, mere frostbite, cold water, residential refrigerators or freezers, or anything that exists naturally at sea level on Earth wouldn't apply at all.

(That said, I got a small liquid nitrogen burn once, and there's a reason they call those "burns.")

Edited at 2012-11-11 05:34 pm (UTC)

If the person is alive, the hydrogen will be rapidly boiling off and so draining all the heat in the area.

An interesting thing with liquid nitrogen is that if you put your hand into it, the boiling of the nitrogen from your body heat will surround your hand with a sheathe of nitrogen gas which insulates it -- I've seen professors do this demo and there's no special trick to it. I've even heard of people putting liquid nitrogen in their mouths briefly and not doing anything worse than damaging their teeth enamel*.

So it might be a slow way to go as either he gets a freeze burn from his restraints (or clothing -- actually that might make it worse, as his clothing would be cooler than bare skin, so the protective shield of gas from his own heat would be less) first and things slowly work there way into his core. The frozen parts themselves might not feel pain, but the nearby tissues would. Which might make him pass out from either the pain of losing large chunks of foot and leg or the loss of blood by whatever ends up there.

* Of course, a professor I worked with claimed to know someone who nearly won a Darwin award for misremembering this story, and assuming that he could swallow liquid nitrogen -- the contraction of the esophagus eliminated the gas cushion, so the liquid nitrogen merrily trashed his digestive system and collapsed his lungs from all that gas trying to get out. (Surprisingly he survived this; hence the 'nearly' -- you don't win a Darwin award unless you kill or sterilize yourself.)

There was a recent case here in the UK of a teenager who was given a cocktail that had liquid nitrogen in it - it was supposed to have evaporated by the time the drink was served, but it hadn't:

"I'd been warned by the barman the drink might make me a bit gassy, so I didn't think too much of it, but then my stomach started to expand and I felt sick," she said in an interview with the Daily Mail.

"Soon I was doubled up with pain. People were asking me if I was all right, but I couldn't say anything because my stomach hurt so much. Everyone went into a panic. I couldn't talk, I could barely walk and everything was just a blur of pain."

Miss Scanlon's friends drove her to Lancaster Royal Infirmary and a CAT scan found a large perforation in her stomach.

During a subsequent operation, surgeons found that the extremely low temperature of the liquid nitrogen had not only burned a hole in her stomach but had completely destroyed her stomach lining.

Her whole stomach had to be removed and surgeons connected her oesophagus, which takes food from the mouth to her stomach, directly to her bowel.

So: deep burns, plus the possibility of an explosion as the liquid comes into contact with human body heat and instantly boils.

This sounds like a perfect question for xkcd's What If? question.

I haven't read all the entries there, so it's possible that they've already answered your question in some form.

I'm going to pretend you mean something more practical like liquid nitrogen, unless there's some particular in-story reason you'd use hydrogen in this case, as it opens up all sorts of procurement and flammability issues. But other than those issues, everything should be the same.

What would be the consequences?

After a few moments for the Leidenfrost effect to dissipate, the person would feel incredible pain during submergence, and within a minute or so (I have no means of estimating a timeframe) a portion of blood will be frozen within the feet and legs, and another portion will continue to circulate but will drop precipitously in temperature before returning to the torso. I'm no biologist but I suspect this is going to cause shock pretty quickly. Necrosis may take some time but I'd imagine frostbite would quickly claim much of the flesh in the limbs. It would probably take at least a couple minutes for all the submerged flesh to drop below freezing.

All my search terms resulted in lots of information on hypothermia, but I imagine that my situation should have very different conseuqences from obvious reasons.

Honestly, they wouldn't be as different as you'd think; they'd just happen much faster.

I'm not an expert on the science of liquid nitrogen, but I do know something about hypothermia, and I agree that the scenarios wouldn't be as different as you might think. I suspect that your victim would ultimately die of some sort of cardiac arrhythmia caused by the cold blood in his/her lower extremities circulating up to the heart - probably long before the areas you'd think of as vital were actually lowered into the chemical. This is exactly the sort of thing that can kill victims of severe hypothermia when they're being rewarmed. Look up "afterdrop" or "rewarming shock." What kills your character won't be the cold itself, but their body grinding its gears because one portion is facing severe cold exposure while the rest continues to function more or less normally.

You would also potentially suffocate, which is the normal issue in industrial accidents with LN2 in the lab


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