Imagine I have this make-believe psionic microbe-or-something that feeds off of the heat energy from combustion.

And let's say that this new fire radiates cold instead of hot.

The big problem with this is that combustion requires heat to maintain itself. So how can this happen?

I've thought of two potential solutions:

  1. The microbe surrounds the flame, absorbing all of the heat and the heat nearby, essentially creating a "cold bubble". Heat exists on the inside of the "bubble", but not on the outside, so that the combustion cycle continues unhindered.
  2. The microbe sits within the flame, absorbs the heat, and its byproducts from this mystery process are able to maintain the combustion process without heat.

Which of these are plausible? And is there another possibility that still fits the theme of a microorganism absorbing fire and instead making it cold?

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    $\begingroup$ Not an answer, 'cos It's late here, but: see non-thermal plasma. That being said, there's no such thing as "radiating cold", as cold is defined pretty much by being the lack of heat. See thermodynamics, particularly about the direction of energy flow towards equilibrium. That being said.... you've added the magic tag, so tell us about your magic system if you want an answer - or make this a reality-check question instead. Could you edit to make it clearer? $\endgroup$ Commented Feb 12, 2021 at 1:07
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    $\begingroup$ (1) What is the phrase "this new fire radiates cold" supposed to mean? (2) The microbe "absorbs the heat", fine, and what does it do with it? Does it send it into hammer space? Becase otherwise it must re-radiate it... $\endgroup$
    – AlexP
    Commented Feb 12, 2021 at 2:02
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    $\begingroup$ It's magic... it can be anything you want. $\endgroup$
    – Monty Wild
    Commented Feb 12, 2021 at 2:06
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    $\begingroup$ You've not a great record with regards questions on this site and I could be quite wrong about the criteria applicable, but please read the help center's bit about question bans, it's bracing. $\endgroup$ Commented Feb 12, 2021 at 3:03
  • $\begingroup$ There's no such thing as radiating cold, because "cold" is pretty much the absence of heat. To "radiate cold" your flame would need to be some kind of aggressive endothermic reaction that produces a light that resembles a flame and somehow magically absorbs all heat from its surroundings, and therefore it would naturally have to stop at some point once the environment no longer had enough heat to keep it going. $\endgroup$ Commented Feb 12, 2021 at 3:27

2 Answers 2


Heat absorption

It would likely be easier to reverse that process. You're stating it is a psionic microbe-or-something, so we can take a bit of creative liberty.

Fire is simply a reaction. It can form over many temperature ranges depending on the material, pressure and more. You say you want a "cold flame", so lets do exactly that.

To "radiate cold" we need to extract heat from the environment. The energy can be stored in nuclear bonds, light or whatever. The microbe-or-something would need to extract it at a rapid pace in a cone above itself. It'll move opposite of the wind, as the wind will push energy towards it, which the microbe-or-something will extract. The cone is created by the psionics to guide it to the organisms surface. Alternatively the 'flames' go down, like cold would do, which will attact the warmer air. So the organism would thrive better on higher surfaces. The resulting condensation and thus mist can be pretty cool.

What the organism would do with the huge quantities of energy, how they store it and such are creative liberties. Maybe they have a way to store it in nuclear bonds, allowing for both huge amount of storage in little space as well as using it later if they can control it. As it's psionic, you can figure something out. Like psionic requires a lot of energy, but can be used to force nuclear bonds together or apart with precision for energy storage or release.


Just throwing this out in case it's of any use:

I don't see any way to use it on a microbe scale but I'm picturing the landing rockets on Perseverance. What's coming out of the rocket nozzles is freezing cold--the engines have converted the heat into velocity.


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