Random question of the night.

Can something be too cold to catch/sustain fire?

Say tomorrow, the earth started going out of its orbit from the sun. It eventually gets super cold on earth...not necessarily snowy, but very, very cold. Can it get so cold that there cannot be a forest fire?.

Can a fire be put out by dropping the temperature super low (without water of course)? For example, if there was a fire in a room, would lowering the temperature of the room affect the fire?

In both cases, oxygen levels are normal, it’s at sea level if that matters, etc...

In theory heat could be "sucked" away too quickly to sustain combustion, but to fire, *everything* is cold. Dropping the temperature of the environment a hundred degrees doesn't matter to fire burning at 800 degrees.

I'm gonna go out on a limb and say it doesn't matter. Fire is a chemical reaction resulting from the combination of fuel, oxygen and heat/combustion. So long as nothing breaks that chain, the reaction continues.

I would think no matter how low the temp, you could strike a flint sparking 1,000+ deg. sparks into whatever dry tinder you have.

Cold temps would make accidental forest fires harder to start and less likely to spread though, like say a lightning ignited one. The sparks would cool off before being able to travel very far.

Forest fires are more complex than just the time of year or season. I've fought wildland fires in the snow. In fact, a few years ago my first federal fire of the season was in a snowstorm.

Fire behavior is a function of fuel moisture, and burn conditions; humidity plays a part, atmospheric stability, wind, ambient temperature, aspect relative to north, slope, position on slope, fuel type, fuel continuity, and other factors serve to inform fire behavior.

High temperatures, low fuel moisture, an unstable atmosphere, low relative humidity, high wind, a south aspect, mid slope, light fuels, available ignition source, a continuous fuel bed with ladder fuel types that run from light surface fuels to denser, heavier fuels higher up, etc, all contribute to high fire behavior. Decrease temps, increase fuel moisture, etc, and you'll decrease fire behavior: flame length, spread rate, burn intensity, fire transport (spotting), and so forth.

Low temperatures: fewer thunderstorms and ignition sources, lower fire behavior.

Remember that fire is a chemical process (heat fuel, oxygen, chemical chain reaction), with four primary components; interrupt any of those, interrupt fire.

Oxygen liquefies at -362 degrees. It might be hard to have a fire then.

If Earth went wandering off, or the Sun went out or whatever, the oxygen levels wouldn't stay the same, they couldn't. It would get too cold for the oxygen to be a gas.

W-wait, don't they already use liquid oxygen (LOX) in liquid propellant rocket thrusters? In fact, isn't it a better oxidizer?

If I remember my college chemistry correctly fire is the result of a chemical reaction in which the fuel (a form of Hydro-Carbon) is raised to a temperature where hydrogen separates from whatever is binding it and it reacts with Oxygen to create the reaction we call fire. If the fuel being used was so cold i.e., wood subjected to a really low temperature say -10/20 degrees F for a long period like in the Artic Circle, that one could not get it hot enough to ignite or to maintain it hot enough to sustain the reaction then I believe the environment could be too cold to sustain fire. Since I didn't stay in a Holiday Inn Express last night, I could be wrong.

0 degrees Kelvin. No fire then, no other chemical reactions either.

quote:

Originally posted by armadill0:
Oxygen liquefies at -362 degrees. It might be hard to have a fire then.

I don't think oxygen needs to to be gaseous to react.

Gunpowder, solid rocket fuel, etc., all have the oxygen atoms attached to other other molecules that, at room temperature and pressure, are solids.

Fuel, heat, oxygen = the fire triangle.

Eliminate one and fire extinguisher. Decrease one and increase another (namely oxygen) , and fire burns. Consider when using a spark to start a campfire. Many of pioneer could start a fire in the dead of winter.

This reseacher claims to have created the coldest spot in the Universe. But maybe some researcher on planet Thrae has done similar research and achieved even colder temps. The topic is actually related to the Bose-Einstein condensate. A bit OT, related to the cold part of your question. And it has lasers,

https://youtu.be/u8wNSVxYZGI

Regarding fire-combustion-ignition, I believe that if you use the right combination of pure elements in proximity you could get fire even at very low temperatures. In particular, aluminium and oxygen. Or pure sodium and oxygen/hydrogen. There is also the possibility of heat/fire/explosion from a critical mass of uranium or a similar unstable radiactive element. I cannot remember being instructed in chemistry nor physics that an element could be so cold that it would not emit radiation by nuclear decay. Except maybe the movie Repo Man.

I will do some internet searching.

The experts state that nuclear decay is not affected by temperature.

This is a brief explanation of the temperature of a black hole.

https://m.phys.org/news/2016-09-cold-black-holes.html

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This is how they do it in the South Dakota snow ~ looks cold to me!




Link:
www.YouTube.com/watch?v=S6ss_5eNABs

There are a couple of 20 second segments where the Capt's microphone is rubbing on his gear causing static. It doesn't last long...

quote:

Originally posted by barndg00:
0 degrees Kelvin. No fire then, no other chemical reactions either.

In theory that's correct. However, I believe absolute zero is only a theoretical limit, and cannot occur in reality.

Being cold can make it much harder to start a fire, but once a fire is going, I don’t believe cold is going to affect it.

quote:

Originally posted by kkina:

quote:

Originally posted by barndg00:
0 degrees Kelvin. No fire then, no other chemical reactions either.

In theory that's correct. However, I believe absolute zero is only a theoretical limit, and cannot occur in reality.

Correct, zero degrees K is thermodynamically impossible and therefore an inane response.

A fire that consumes oxygen (there are others, such as nuclear fires) requires free radicals and temperature can play a role on their generation / reduction but to what degree is very context dependent.

quote:

Originally posted by Aeteocles:

quote:

Originally posted by armadill0:
Oxygen liquefies at -362 degrees. It might be hard to have a fire then.

I don't think oxygen needs to to be gaseous to react.

Gunpowder, solid rocket fuel, etc., all have the oxygen atoms attached to other other molecules that, at room temperature and pressure, are solids.

Liquid oxygen works GREAT for burning stuff.

Look what happens when you touch a match to a cracker that has been soaked in liquid oxygen:




Link to original video: https://youtu.be/TgcynkLkuJw

quote:

Say tomorrow, the earth started going out of its orbit from the sun.

I'll take just a WAG that in this case the atmosphere would be stripped away. No air (oxygen), nothing to start a combustion reaction.

Based on trying to start a fire in cold temps (-30 or so) - I can state with absolute certainty that it takes longer to start that initial fire... Strike a match and it takes a second or two before it flames. Hold the match on paper and it takes much longer before that paper catches.

However, I don't know if that means there is a temp at which fire just doesn't 'work'. My guess is that it'll just take longer to raise the temp of the material you're trying to burn to ignition temp. *shrug*

quote:

Originally posted by kkina:

quote:

Originally posted by barndg00:
0 degrees Kelvin. No fire then, no other chemical reactions either.

In theory that's correct. However, I believe absolute zero is only a theoretical limit, and cannot occur in reality.

Once you near absolute zero molecules would be moving so slowly it would likely take a whole lot of energy to start a fire. I'd say probably could not start a fire or any chemical reaction near absolute zero.