alt Hacker NewsThe next obvious question is where do they come from since presumably there weren't dinosaurs and plants dying there 300 million years ago.
Went on a bit of a rabbit hole and it appears that there is a lot of methane in the atmosphere and that gets broken down via photolysis into hydrocarbons somehow, and the methane likely is there from the formation of the moon originally via methane ice.
> gets broken down via photolysis into hydrocarbons somehow
See Figure 2 [1]. Protons, electrons and water ions from space dissociate, in the presence of sunlight, nitrogen and methane. Those combine into intermediate-mass hydrocarbons that produce complex organics. The part we don't understand is how those complex organics, e.g. benzene and naphthalene, turn into large organic particles.
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC10961852/#fig2