as for the moon near Jupiter it doesn't have liquid water, it has liquid methane, its THAT cold. i doubt we'll find anything living there because of how cold it is, it just seems to me that a place that is that cold the atoms aren't moving fast enough for them do do anything. as for that other volcanic planet your talking about the whole planet is molten, so unlikely anything there. bacteria don't tend to grow on lava flows, though there are some that can withstand alot of heat but lava flows i think thats just a little be too much for them.
as for the argument that the universe is too big, well that may be the case but the universe is also VERY harsh. look into the amount of radiation that is given off my super novas and things of that ilk. ill tell you this much if one were to happen in a near by system our solar system would not be a very nice place to live.
i should point out that i am not saying life doesnt exist out there only that really people we cant know.
Oh and a cookie for whoever can tell me the answer this paradox.
If the universe is so big so infinitely huge, estimates suggest numbers to be around 10^22 and if light always travels in a strait line and since space is empty literally mass has a density of around 10 or 15 atoms per square meter. why is the night sky black and doted with pin points of light?