Earths, yes, but there are hydrocarbons elsewhere that are not biological in origin. “Methane (CH4) is abundant on the giant planets—Jupiter, Saturn, Uranus an

Earths, yes, but there are hydrocarbons elsewhere that are not biological in origin. “Methane (CH4) is abundant on the giant planets—Jupiter, Saturn, Uranus and Neptune—where it was the product of chemical processing of primordial solar nebula material. On Earth, though, methane is special. Of the 1,750 parts per billion by volume (ppbv) of methane in Earth’s atmosphere, 90 to 95 percent is biological in origin.”[1] [1] https://www.scientificamerican.com/article/methane-on-mars-titan/ https://www.scientificamerican.com/article/methane-on-mars-t...