Saturn’s moon Rhea has oxygen and carbon dioxide in its atmosphere.
The oxygen is not that big a deal, but the carbon dioxide has them thinking maybe some proto-life is respirating.
I’ll be in my bunk.
My take is that if there is enough energy to split water, then there is certainly enough energy to burn methane. Since the other moons of Saturn have methane, I would assume that there is at least a source of methane. Really, I don’t see why CO2 would be surprising. I thought a lot of objects in our solar system had CO2.
Also, if there’s enough energy to split water, life doesn’t have much chance. I won’t rule it out, but that’s a lot of energy.
You have it backwards. Carbon dioxide doesn’t require the presence of life to be created – as others have said, it could easily result from the combustion of methane. Oxygen’s a bit more interesting (since proto-life would most likely “exhale” oxygen) but even that can be accounted for w/o the presence of life.
Actually, free oxygen would be more indicative of life than CO[sub]2[/sub], insofar as carbon dioxide is formed as the byproduct by any number of exothermal processes while free oxygen tends to recombine with other elements (like hydrogen, lithium, carbon, nitrogen) at the slightest provocation and therefore must be constantly generated by some dissociation reaction. In the case of Rhea, however, the atmosphere is so tenuous and the temperature regime so low (not accommodating of liquid water) that nothing we would think of as life is likely to form there.
Stranger