O3 is formed out of O2. What would you have O2 formed out of? Windborne rootless plants?
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No: In the ozonosphere, three O2 molecules are (temporarily) formed from two O3 molecules. Then, the process is reversed. Thus, atomic oxygen (i.e., single atoms of oxygen) is also present to a certain degree. And don't forget that - compared to ground level - it's a near-vacuum up there. Methane in such miniscule concentrations wouldn't "burn" with a visible flame.
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