Iv'e been following the idea that all microbial life that has existed here has served a purpose for which humans are the penical of the beneficiary. (Some life forms have worked to our disadvantage but even that, God uses to show us something.) The question is, what purpose does microbial life have on other planets (well, moons) serve when we will probably never be able to see them anyway? (except, maybe if mars lander type ships are sent to them. That's if this is possible with the giant planet near by). We can now see geysers and such on far away planets and moons but that could be teaching us merely how creation was done.
As far as so much wasted space, one may wonder why we would be the only life sustaining planet. Well, science has found (theorized) that the mass at the beginning of the universe (big bang or "God Awsome Blast") had to be exact. In fact it is therorized that not even the mass of a dime could have been added or taken away from that initial space for the right elements to form for life to be on this little planet. Well, all of that mass had to go somewhere. So now the universe is several billion light years across. Guess it was necessary.
But now for our real science lesson:
Atmosphere + Water = Life