> According to Cassini data, scientists announced on February 13, 2008, that Titan hosts within its polar lakes "hundreds of times more natural gas and other liquid hydrocarbons than all the known oil and natural gas reserves on Earth." The desert sand dunes along the equator, while devoid of open liquid, nonetheless hold more organics than all of Earth's coal reserves.
The 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.
"abiogenic oil" is a fringe belief that I just can't stop myself from giving some credence to. I know all the experts say it's not true, and I'm not crazy enough to deny the evidence, but there's still the niggling doubt in the back of my mind. There's so many hydrocarbons out in space.
I thought they discovered at least decades ago that our oil is actually largely inorganic? It's not dinosaurs & ferns but a direct chemical & physical process. I know a lot of people still say it's just a competing theory but they have found many large deposits in places where it's not possible for it to have been organic. (too deep, in the middle of pure granite with only raw volcanic material and no other organics, etc)
Oil is fluid, so it will not necessarily stay where it is formed, but it will flow through the rocks until it is stopped by impermeable rocks, like granite.
So there is nothing surprising in finding oil elsewhere than where it has formed.
Some hydrocarbons can form in the absence of life, e.g. by Fischer-Tropsch synthesis from syngas, catalyzed by some minerals, where syngas can form in volcanic gases or in hydrothermal vents. However that is likely to have been a negligible contribution to the oil reserves of the Earth and most or all oil ever found has a chemical composition that has clear indications of being produced by the decay of organic matter from living beings.
As far as I understand it, people looking for oil using theories that oil is formed from organic processes have had significantly more success than people looking for oil using inorganic theories, and not for lack of trying on the latter side.
It's pretty common for hydrocarbons to migrate down from source rocks down into basement along fracture lines or surface weathering, no abiogenesis required.
I'll take the opportunity to share this beautiful sci-fi video that is (ostensibly) about oil extraction on the exoplanet Solstice-5:
https://youtu.be/Gl2hTmgG18k
Edit: GPT says hydrocarbons yes, oil as in Earth no (because that comes from complex living matter).
Edit 2: As far as we know, I really hope there's more life out there.