My source of amazement, and one of the reasons I'm into the environment, is that we seem to be the oddball planet, at least within a few hundred light-years, that has such prolific life, such diversity of life, and such a wondrous balance of everything working together.
Now and then you hear that someone found that there may have been water on Mars, or signs of life on this planet or that planet, but absolutely nothing that resembles the complexity of life we have here.
I've seen the recent news about the planet Kepler that seems to have a similar atmosphere but, again, that's in another whole galaxy. It is just crazy how evolution has taken the different paths it has so that we are where we are, and being as "smart" as we are, what do we do but set about like locusts putting us on a course that will turn back the clock on our rich and abundant biodiversity.
As for aliens, maybe there are some out there somewhere.Who knows. I guess anything's possible.