I have been to a lot of talks recently about exoplanets, with content at all levels (from school lectures, to professional research seminars). The whole business is, without doubt, a very exciting area of study. The endeavour has moved beyond the initial fanfare of discovery to one of documentation, building up a picture of the relative proportions of the different types of objects out there. The hope is that we will soon begin to find evidence for truly Earth-like exoplanets. And then there’s the possibility of extraterrestrial life. In almost all of the presentations I’ve been to, I have heard the speakers say that the implications of finding evidence for life on a planet beyond Earth would be profound (“profound” is very much the word of choice). To some extent we’ve been there before with the notion on life on Mars – some would say it has already been discovered, but for most it is still not proven beyond any reasonable doubt.

As I get older I’m beginning to question just how significant such a discovery would actually be. The fact that we are here to ponder the question at all is proof that the laws of physics in our Universe are such that (intelligent) life is inevitable. So, we shouldn’t be surprised by the fact that we are here. And just on the grounds of statistics alone there are unquestionably, within the Universe, many other places like Earth, in planetary systems like our own (i.e. whether or not we’ve observed them). Given that life has been present on Earth for at least a couple of billion years, if not for more than 80% of its existence, it seems inevitable that Earth-like planets elsewhere in the Galaxy/Universe are bound to harbour life of some sort (of course, I’m hardly the first person to ever think or write this).

Yes, it will be cool when someone (or rather, some thing since it will be an electronic device of some sort) detects a signature of life on an exoplanet (e.g. a spectral signature of an atmosphere containing methane or ozone). And the detection of the second such planet will be equally rewarding. But what of the 3rd, 4th, 5th…? How many Earth-like planets will need to be observed before we’re bored with such things? Not many I would imagine. At this point it will no longer be profound.

I guess the thing about finding life on Mars (which we pretty much know for sure could only ever be primitive in nature) is that there would then be the possibility to study it (always assuming that the lawyers, ethicists and planetary protection police would allow us). The frustrating thing about detecting signs of life on a planet 50 light years away would be that it is 50 light years away.

No, I think what would be really profound is finding no evidence for life (beyond Earth) anywhere in the Universe.

(With due acknowledgement to Arthur C. Clarke).