There's an interesting report on Princeton University's website (found via slashdot ) about ancient bacterial life being found two miles below the surface of the Earth. The point taken from this is that if life can survive in such inhospitable conditions on Earth, it can survive in equally inhospitable conditions elsewhere, with the key point of interest being Mars.

Steven Den Beste was talking about Mars the other day. His belief is that despite some recent claims to the contrary, the evidence is clear that in the past Mars had both water oceans and an atmosphere (necessary for the oceans). I tend to agree. If Mars had both these things, it seems extremely likely that life would have evolved. (Current evidence suggests it isn't all that hard, although there is a fair amount of supposition). If life evolved then, and if life can live in environments as hostile as this Princeton study shows, then it seems extremely likely that there is some still there. It may have retreated miles underground, and it may be very simple life, but it is surely still there).

Fifteen years ago, I believed that the solar system was empty of life except for on Earth, and that while there was probably going to be life elsewhere in the universe, we would have to travel a long way to find it. Now I am quite confident of the opposite. Life on Mars (or Europa) may not be very interesting life, but I am fairly confident it is going to be there.