Defining Life Into A Corner

With all the exoplanets being discovered, scientists are trying to define exactly the parameters of the type of worlds that may be home to life. That's what scientists do, and the fact is that Science has been remarkably successful at revealing the universe in its wondrous complexity.

Establishing parameters, however, can be tricky-- precisely because Nature is so complex. Various elements for a life-bearing world have been proposed, everything from the presence of liquid water on the surface of a world to the axial tilt, which should be present, but shouldn't be too extreme.

Taken separately, each such factor may have merit, but added up we tend to get a world almost exactly like Earth. Since Earth life is the only life we know, that's fair and understandable, but it might miss the bigger picture. Exploring the universe should be about opening our minds to possibilities. Over the latest three decades, we have found life on Earth in some shocking places, after all. Any parameters applied to other planets should probably by loose-- in acknowledgement of the simple fact that we are still in the very early days of understanding life in all its possible manifestations.