I believe due to the nature of the universe that life in and of itself is actually quite "common place." I believe its on all the planets and even the sun, but exists in such a way its either too primative or too advanced for us to know thats what it is. My evidence is speculative at best i know, but for one thing Extremophiles (the fact that closer to earth based life can handle such extremes), any compound whether its a molecule or a compex super organism will survive til it can't. Evidence two, storm systems by a vague definition are living things. They reproduce, grow, consume, require gases, use electrical energy or produce it, etc.. storm on jupiter? Thousand year old life form. Makes you wonder what else is under there huh?