[X] My Assistant

[Floyd]

It has been quite cold in Boston for awhile, and as I sat in front a nice warm fire visiting Mars and Saturn at UMSF, my wife, Laura, asked whether fire is possible on planets without life. After some thought, I answered no.
I’m interested in your feedback. The things on Earth that burn ie wood, oil, coal, are mostly of organic origin. Furthermore, the oxygen in our atmosphere was put their largely by plants. Is the drastic chemical disequilibrium necessary for occasional surface fires on a planet dependent on living organisms? Are surface (forest) fires on a planet a sign of life? I’m sure this question has been addressed in science or literature (SF) before and would appreciate any references or links.

What other chemistries could produce a nice fire if we wanted a “bonfire” at Victoria for the UMSF picnic? Anything UMSFers could gather from the planet surface in a massive treasure hunt? I hope we don’t have to each bring a stick from Earth and an oxygen tank!
Floyd

[nprev]

Excellent point, tty; anerobes rule!

Come to that, an oxygen-enriched atmosphere is really a very limited indicator, albeit an apparently unambiguous & quite detectable one. O2 allows high-energy organisms (and fires) to exist, but who's to say that a largely chemosynthetic rather than photosynthetic biosphere would not be equally viable or complex?

We know nothing yet, really...hope to live long enough to see some answers!

[JRehling]

[...]

[Juramike]

Another angle to this would be that you could potentially, on a lifeless planet, have a big fire (in O2, Fl2, or Cl2)... once. If some quirk of, let's say, the introduction of a hitherto trapped reservoir in the crust or in oceans made it's way to the atmosphere, you could get a single catastrophic burn-off that would last until the chemical energy were exhausted, and then end, forever.

Actually, you might get away with it more than once. The terrestrial analog would be a gas vent (petroleum, natural gas, methane in a swamp) lighting up in the oxygen atmosphere. It vents, it burns for a while, then burns itself out.

If there was a geochemical process that could regenerate the key reactive species (I haven't a clue how fluorine gas could be (oxidized?) back down to F2 geochemically), this whole process could repeat itself ad infinitum. All without having to invoke biology.

I would not be suprised to find that some very funky sulfur redox chemistry is occuring on Io right now, possibly involving generation of a flame somewhere in the cycle.