The second reason is more abstract, but so fundamental to our grasp of who we are that it can't be easily dismissed: we should go to Mars to search for life there. This is a new idea; after the Viking landings in 1976 it was assumed that Mars was lifeless. But since then we have discovered life on Earth in such unlikely harsh environments that a new word, "extremophiles," has been coined to describe these hardy microbes. It appears now that life can exist anywhere there is water and some minerals. Mars may have these ingredients in abundance, far under its frozen surface Scientists have already claimed to have found fossil bacteria in the Martian meteorite ALH84001, and while this particular finding is contested, the possibility that life once existed on Mars is generally acknowledged, as is the possibility that it is still there deep underground. If we go there and find life, or even fossil evidence of past life, it would be one of the most important scientific discoveries in history.
