If a match is lit in an atmosphere like earth’s but outside of gravity’s pull, will it suffocate? Will it snuff out from its own gases faster than if it had a steady earthbound updraft to refresh it with more oxygen? I heard the space shuttle astronauts were doing tests with fire in microgravity. I missed reading any results so all I can do is guess: it snuffs. My earthist rivals insist fire will burn in zero Gs; some say heat rising will start a draft which in turn ventilates the reaction. I immediately ask: which way is up? Duh! –John Inkman, Hodgkins, Illinois
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It is just this kind of restless curiosity, John, that is at the heart of all great science. They’ve been doing a bunch of fire experiments on the space shuttle lately, and while the scientists’ official line is that they’re trying to advance the frontiers of knowledge, etc, one suspects that in a secret corner of their hearts they just want to know, among other things, whether a flame would smother in its own smoke.
So there’s your basic answer. Now for the hedging. It turns out that with a little tweaking you can get stuff to burn in zero Gs just fine, in some cases better than it would burn on earth. NASA has been burning paper and other stuff in zero Gs both on the space shuttle and in “drop towers” on earth, where you can get a few seconds of weightlessness while something is in free-fall. If there’s the slightest breeze, as opposed to the dead still air in the candle-flame chamber, enough oxygen gets through to sustain combustion. Pump in 35 to 50 percent oxygen instead of the normal 21 percent and you’ll get a self-sustaining flame even in still air. Adjust the air flow just so and you can get some weak flames to burn longer in zero Gs than they would on earth, where too-hearty convection currents can cause a flame to blow itself out. So there you are. Who says the space program doesn’t have practical results?
Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.
