What kind of ambient cold damage would near absolute zero do?

Ottriman · 02-10-2016, 02:28 PM

I ask this because several potential future characters for my game could cool things down to near absolute zero on a moderate to large scale.

I suppose I should ask for several version here.

1. Person is just standing on the ground when it happens
2. Person is in water when it happens

Thanks.

mr beer · 02-10-2016, 02:33 PM

Are you positing that the environment around the character goes from normal temperature to immediately absolute zero? Because in that scenario, the atmosphere will snowflake/rain into vacuum and the water will turn into ice in an instant, I think.

The sudden creation of vacuum in normal Earth conditions might be more hazardous than the temperature change.

Ottriman · 02-10-2016, 02:39 PM

Quote:

Originally Posted by mr beer

Are you positing that the environment around the character goes from normal temperature to immediately absolute zero? Because in that scenario, the atmosphere will snowflake/rain into vacuum and the water will turn into ice in an instant, I think.

The sudden creation of vacuum in normal Earth conditions might be more hazardous than the temperature change.

I am more thinking a rapid change over like 10 seconds actually.

mr beer · 02-10-2016, 02:52 PM

OK, well in water, assuming temperature change is constant, the character maybe has 1 second to exit the area of effect before being frozen in place. In 10 seconds, they are entombed at absolute zero and probably frozen solid.

In atmosphere, cold damage will depend upon clothing but as I say, within a few seconds, the various gases are going rain out, creating a vacuum which will be filled by more air rushing in. So that's going to get pretty complex.

RyanW · 02-10-2016, 02:58 PM

I'm going to assume it stays above the boiling point of oxygen, because once you start locally condensing out major components of the atmosphere... bad things happen, probably.

If it cools everything in the area, including human bodies (and why wouldn't it), pretty much instant death. I suspect a race between tissue damage due to crystallization and your body just plain stopping. If somehow human bodies aren't affected directly, the cold would probably do tissue damage equivalent to, if not worse than, being on fire.

Anaraxes · 02-10-2016, 03:03 PM

This is one of the times that the "buy the effect, not the name" mantra comes in handy. If a character wants to kill people by freezing them, buy an Innate Attack that freezes people, and have the fluff description say that the character is bringing down the temperature of the immediate envionrment, rather than trying to speculate on "logical" physical consequences of some general ability like Create Cold or Control Temperature. That path just leads to lots of arguments and abuse.

Ottriman · 02-10-2016, 03:08 PM

Quote:

Originally Posted by Anaraxes

This is one of the times that the "buy the effect, not the name" mantra comes in handy. If a character wants to kill people by freezing them, buy an Innate Attack that freezes people, and have the fluff description say that the character is bringing down the temperature of the immediate envionrment, rather than trying to speculate on "logical" physical consequences of some general ability like Create Cold or Control Temperature. That path just leads to lots of arguments and abuse.

I know about that but speculating on the logical physical consequences is what I'm here for, it would help me model the ability (which btw will be twinked out temperature control, GURPS basic set just doesn't describe ultracold environments in any decent way.)

mr beer · 02-10-2016, 03:21 PM

In air, I'm not sure how damaging 10 seconds of dropping to absolute zero would be.

Initially, yeah it's cold but one second of cold is nothing. Then you hit severe sub-zero for a few seconds, which is unpleasant but not really damaging in that time frame. Then the atmosphere rains out, now we're in a vacuum, which doesn't conduct heat well. I think the most damaging thing might be atmospheric water freezing onto your skin and particularly mucous membranes.

Maybe make a HT check at a penalty depending on clothing level, take some Fatigue damage plus say 1d+1 from water contact and the occasional drop of liquid air or whatever? Critical failures mean you take extra damage or you are Blind from your eyes getting rained on.

The ancillary problem of being in a vacuum very much depends on area of effect I think.

Would be extremely deadly in a sealed room, with a small area of effect and outside, it might be trivial for a character to simply move away.

This supposes it's not the character that's being directly reduced in temperature, if that's happening, of course they are going to take huge damage.

simply Nathan · 02-10-2016, 03:37 PM

Every single water molecule in your body freezes into a crystal state suddenly

You die, no save

Anaraxes · 02-10-2016, 03:47 PM

So, then, ice has about three times the thermal conductivity of water, which in turn has 3-4 times the thermal conductivity of dry soil.

In rough terms, hypothermia will render you unconscious in about an hour in water at 10 C. Cut the time in half for every 5 degrees C you drop the temperature. Hypothermia kills in about three times the unconscious time. You lose most of your dexterity / functional ability in about 1/5th the unconsciousness time. Nobody bothers to measure this below 0 C (15 minutes), not least because the water would freeze and we have no practical experience to measure.

Entombed in ice, you'll go unconscious / die three times faster than in super-cooled yet somehow liquid water.

Heat transfer rate is proportional to temperature difference, so a -270 C heat sink should freeze you about 8 times as fast as a 0 C heat sink. Call it unconsciousness in 1-2 minutes, death in 5, inability to function in 10-15 seconds. (In actuality, the temperature difference is constantly decreasing so the transfer rate is also decreasing, so the times will be longer, but I'm too lazy to try and break out the calculus.)

Freezing the atmosphere out actually isn't going to affect a target via cold much. No atmosphere means no matter in contact to conduct or convect heat away. Death by ejection from an airlock occurs by ebullism (bubbles forming in blood and other fluids due to lack of pressure; "the bends") and hypoxia. Ebullism is faster; say unconsciousness in 15 seconds and death in 90. Hypoxia is just suffocation; might as well use those rules if the victim has pressure support yet still can't breathe.

For standing on frozen ground in a vacuum, I'll go out on a limb without looking up it and assume that the heat flux is proportional to the surface area involved. So, multiply the hypothermia times by, say, 10, as you freeze from the feet upward; also multiply by that factor of 3 for dry soil. So you get to live 30 times as long. More realistically, you'll probably fall over as your feet and legs lose function, and then you'll have even more surface area in contact with the ground.

The forum has a number of physicists that can correct all of my terrible assumptions, extrapolations, and downright errors in the above, so you'll want to see what others have to say. But you know the proverb: the fastest way to get an answer on the Internet isn't to ask a question, but to post the wrong answer, and wait for people to rush to correct you...

(I assume there's a reason for not just freezing the victim directly; if you can drop the atmosphere to 0 K, might as well drop the victim's body to 0K instead for instant death. Then you can ask the question the other way around: how much atmosphere condenses on the body before it warms up enough for that to boil away again?)

02-10-2016, 02:28 PM	#1
Ottriman Join Date: Apr 2015	What kind of ambient cold damage would near absolute zero do? I ask this because several potential future characters for my game could cool things down to near absolute zero on a moderate to large scale. I suppose I should ask for several version here. 1. Person is just standing on the ground when it happens 2. Person is in water when it happens Thanks.

02-10-2016, 02:33 PM	#2
mr beer Join Date: Mar 2013	Re: What kind of ambient cold damage would near absolute zero do? Are you positing that the environment around the character goes from normal temperature to immediately absolute zero? Because in that scenario, the atmosphere will snowflake/rain into vacuum and the water will turn into ice in an instant, I think. The sudden creation of vacuum in normal Earth conditions might be more hazardous than the temperature change. Last edited by mr beer; 02-10-2016 at 02:37 PM.

02-10-2016, 02:52 PM	#4
mr beer Join Date: Mar 2013	Re: What kind of ambient cold damage would near absolute zero do? OK, well in water, assuming temperature change is constant, the character maybe has 1 second to exit the area of effect before being frozen in place. In 10 seconds, they are entombed at absolute zero and probably frozen solid. In atmosphere, cold damage will depend upon clothing but as I say, within a few seconds, the various gases are going rain out, creating a vacuum which will be filled by more air rushing in. So that's going to get pretty complex. Last edited by mr beer; 02-10-2016 at 03:16 PM.

02-10-2016, 02:58 PM	#5
RyanW ☣ Join Date: Sep 2004 Location: Southeast NC	Re: What kind of ambient cold damage would near absolute zero do? I'm going to assume it stays above the boiling point of oxygen, because once you start locally condensing out major components of the atmosphere... bad things happen, probably. If it cools everything in the area, including human bodies (and why wouldn't it), pretty much instant death. I suspect a race between tissue damage due to crystallization and your body just plain stopping. If somehow human bodies aren't affected directly, the cold would probably do tissue damage equivalent to, if not worse than, being on fire. __________________ RyanW - Actually one normal sized guy in three tiny trenchcoats.

02-10-2016, 03:03 PM	#6
Anaraxes Join Date: Sep 2007	Re: What kind of ambient cold damage would near absolute zero do? This is one of the times that the "buy the effect, not the name" mantra comes in handy. If a character wants to kill people by freezing them, buy an Innate Attack that freezes people, and have the fluff description say that the character is bringing down the temperature of the immediate envionrment, rather than trying to speculate on "logical" physical consequences of some general ability like Create Cold or Control Temperature. That path just leads to lots of arguments and abuse.

02-10-2016, 03:21 PM	#8
mr beer Join Date: Mar 2013	Re: What kind of ambient cold damage would near absolute zero do? In air, I'm not sure how damaging 10 seconds of dropping to absolute zero would be. Initially, yeah it's cold but one second of cold is nothing. Then you hit severe sub-zero for a few seconds, which is unpleasant but not really damaging in that time frame. Then the atmosphere rains out, now we're in a vacuum, which doesn't conduct heat well. I think the most damaging thing might be atmospheric water freezing onto your skin and particularly mucous membranes. Maybe make a HT check at a penalty depending on clothing level, take some Fatigue damage plus say 1d+1 from water contact and the occasional drop of liquid air or whatever? Critical failures mean you take extra damage or you are Blind from your eyes getting rained on. The ancillary problem of being in a vacuum very much depends on area of effect I think. Would be extremely deadly in a sealed room, with a small area of effect and outside, it might be trivial for a character to simply move away. This supposes it's not the character that's being directly reduced in temperature, if that's happening, of course they are going to take huge damage. Last edited by mr beer; 02-10-2016 at 03:27 PM.

02-10-2016, 03:37 PM	#9
simply Nathan formerly known as 'Kenneth Latrans' Join Date: Aug 2009 Location: Wyoming, Michigan	Re: What kind of ambient cold damage would near absolute zero do? Every single water molecule in your body freezes into a crystal state suddenly You die, no save __________________ Ba-weep granah wheep minibon. Wubba lubba dub dub.

02-10-2016, 03:47 PM	#10
Anaraxes Join Date: Sep 2007	Re: What kind of ambient cold damage would near absolute zero do? So, then, ice has about three times the thermal conductivity of water, which in turn has 3-4 times the thermal conductivity of dry soil. In rough terms, hypothermia will render you unconscious in about an hour in water at 10 C. Cut the time in half for every 5 degrees C you drop the temperature. Hypothermia kills in about three times the unconscious time. You lose most of your dexterity / functional ability in about 1/5th the unconsciousness time. Nobody bothers to measure this below 0 C (15 minutes), not least because the water would freeze and we have no practical experience to measure. Entombed in ice, you'll go unconscious / die three times faster than in super-cooled yet somehow liquid water. Heat transfer rate is proportional to temperature difference, so a -270 C heat sink should freeze you about 8 times as fast as a 0 C heat sink. Call it unconsciousness in 1-2 minutes, death in 5, inability to function in 10-15 seconds. (In actuality, the temperature difference is constantly decreasing so the transfer rate is also decreasing, so the times will be longer, but I'm too lazy to try and break out the calculus.) Freezing the atmosphere out actually isn't going to affect a target via cold much. No atmosphere means no matter in contact to conduct or convect heat away. Death by ejection from an airlock occurs by ebullism (bubbles forming in blood and other fluids due to lack of pressure; "the bends") and hypoxia. Ebullism is faster; say unconsciousness in 15 seconds and death in 90. Hypoxia is just suffocation; might as well use those rules if the victim has pressure support yet still can't breathe. For standing on frozen ground in a vacuum, I'll go out on a limb without looking up it and assume that the heat flux is proportional to the surface area involved. So, multiply the hypothermia times by, say, 10, as you freeze from the feet upward; also multiply by that factor of 3 for dry soil. So you get to live 30 times as long. More realistically, you'll probably fall over as your feet and legs lose function, and then you'll have even more surface area in contact with the ground. The forum has a number of physicists that can correct all of my terrible assumptions, extrapolations, and downright errors in the above, so you'll want to see what others have to say. But you know the proverb: the fastest way to get an answer on the Internet isn't to ask a question, but to post the wrong answer, and wait for people to rush to correct you... (I assume there's a reason for not just freezing the victim directly; if you can drop the atmosphere to 0 K, might as well drop the victim's body to 0K instead for instant death. Then you can ask the question the other way around: how much atmosphere condenses on the body before it warms up enough for that to boil away again?)