The presence of methane, a hydrocarbon, on Jupiter must be “proof” that dinasaurs once roamed Jupiter! Today a substantial amount of the earth’s petroleum deposits may very well be composed of recycled ancient plants and animals, but I happen to believe that planets in our solar system having the elements hydrogen, carbon, oxygen, and sulfur also have a mechanism for creating petroleum from them even if these elements were not associated with plant or animal life. Thus it may be entirely possible that the earth’s petroleum supply is not finite because the total amounts of these elements are unchanging.
When comet Halley came by during 1988 the Europeans (NOT nasa) took close up pictures of it. They saw a black part that was much bigger than what they thought the comet should be. They discovered a surprise: the comet was 4 times bigger in size than they had thought. That meant it was 4 cubed times more massive, or about 64 times.
It was black because it was covered with a dirty, tar-like material. Their sensors found it was "kerogen", CH2.5 polymer, which is something like oil shale.