I have to assume, first of all, that this is a serious question. It is important because, up until now, for thousands of years, we have always thought that life in this universe was unique to this planet alone.
Many religions profess such a claim.
Now there is the very real possibility that, once again, we must radically alter how we feel about ourselves in the universe. Not only did Copernicus wrench us from the center of the universe, and Harlow Shapley displace us from the center of the Milky Way, but now the very fact that we are living organisms is not unique. If in the last year we have detected planets around other stars, and possible bacterial fossils on Mars, we now have for the first time in human history the prospect that planets like Earth with at least simple organic life may be common. We used to think that life was fragile, but if it can appear in two places in our solar system on very very different planets, at least bacterial life must be ubiquitous. Copyright 1997 Dr. Sten Odenwald Return to Ask the Astronomer .