When most of us think about alien life, the images we conjure up are often suggested by the media is productions like Star Trek or Dr. Who. But these ideas almost always are simply a slight change from the life forms with which we are familiar. Perhaps aliens have pointy ears or wear vaguely medieval clothes, but they are not truly alien.
This week, however, a serious scientific suggestion has been made that alien life already exists on Earth. We just don’t recognize it. In fact, we haven’t even really looked for it.
Alien life, physicist Paul Davies suggests, is quite possibly living in Earth’s most alien environments – under conditions of extreme heat or cold, intense pressure, or surrounded in what life as we know it would find toxic. It may not even be based on the carbon/hydrogen/oxygen combination which characterizes all life with which we are acquainted.
Would any of this matter in any practical sense? Professor Davies says that what he believes may have happened is that life may have arrived colonized Earth on at least two separated occasions. It may have arrived on a rock from Mars or on the tail of a comet from some place else. But if life arrived and thrived on this single planet twice in Earth’s five billion year existence, then almost certainly the Universe is teeming with life.
And we are not alone.
Professor Davies is looking.