The Science of SETI

Views of SETI are diverse. SETI Australia Centre Chairman Dr Frank Stootman provides some insights into the realities of SETI, the Search for extraterrestrial Intelligence:

A balanced view of SETI - doing good science

Like anything in life SETI attracts all sorts of extreme views. At one end are the naysayers who just wipe off self-identifying life as a possibility simply as a gut level reaction without too much consideration of the options. For them it is patent nonsense that there is life out there and for them too, any money spent on this sort of activity is just plain nonsense. At the other end of the spectrum are the supreme optimists for whom it is equally obvious not only that there must be intelligent life out there but also who are ready to throw money at and be involved in all sorts of schemes to communicate with UFO's and aliens.

There are in fact two issues to be faced by us all if we are to search for extraterrestrial self-identifying life.

First, is the straight objective mechanics of making a convincing detection that such life exists.

We are looking for potentially artificial signals in amongst the myriad of signals coming from outer space. Intelligent life, if it were interested in communicating, would have to send signals which are distinguishable from other sources and with the sensitivity of our current telescopes such signals would have to be *deliberately* beamed towards us. This is true even if we are talking about sources at a distance of our closest star neighbour, Alpha Centauri, at 4.3 light years away. We do not, at present, have a hope of picking up stray broadcasts from objects at such distances. Essentially it is beamed information we are searching for and we must be *dispassionate* at this point.

Doing good science demands that we let our instruments do the measurement as best as we possibly can. It is also to be remembered at this point that 30 years of such science has been done without any signals which are reproducible to the point of being interesting. It is true we are improving the search techniques all the time and it is also true that there are a huge number of possibilities as to what we might find and where to look. Yet good science demands care and objectivity.

Science too, is rightly sceptical of claims that UFOs and aliens have visited us simply because calculations based on science tell us that such travel is almost impossible. To give you an idea of the difficulty of space travel. Let's ignore, for the moment, all sorts of gravitational effects which would capture a rocket on its travel to us from Alpha Centauri (only 4.3 light years away). A light year is approx 9,500,000,000,000 km and even if a rocket travelled at 10 times the escape velocity from Earth it would take approx 13,000 years to get here. That is almost the life time of all civilisation on earth! So you see it is *extremely* unlikely that aliens could visit us directly.

Of course, some have suggested that they have sent robots and it is with these we might communicate via (say) the internet. The problem with this notion is that the *senders* of the information would benefit little from such communication. We would certainly know that others existed and that is important but communication, in the alien/UFO sense, would still not be possible.

Second, an issue we also need to face. The whole issue of searching for life is shrouded by *metaphysical* issues. By 'metaphysics' I mean literally mean 'beyond' - physics. Persuasion, conviction, optimism and pessimism about the existence of self-identifying life are an important context in which we do objective science. All that is being said here is that science is not done in a metaphysical vacuum. We do science, give priorities to projects in science and spend resources on the basis of such metaphysics. But metaphysics is a broad area which involves lots of human traits.

Our belief systems - religious or otherwise, our assumptions, our desires and hopes. Perhaps in the case of SETI, our cosmic significance too. We live increasingly in a world looking for spiritual understanding of ourselves. The rejection of traditional religion has opened a way to new spiritual searches. These may be a Paul Davies' 'Mind of God' or new age crystal power or, indeed, spirituality in a quest for aliens. As such there are going to be naysayers and enthusiasts for all sorts of reasons. And equally, for all sorts of reasons, such parties are going to be against or for SETI.

So, we need to understand the issues at two levels. Firstly on the science side we need to strive for excellence at doing the best possible science, and, secondly, inextricably tied to the first, on the metaphysical side, we need to open up debate on the big issues which confront us as human beings. If we should find self-identifying life and it can be proven objectively that such exists then indeed we have found something absolutely astounding! Yet equally, if after many years of work we do not find evidence for artificial signals then we may lose interest or perhaps conclude that, for all intents and purposes, we are alone. Such a conclusion also has far reaching implications.

Associate Professor Dr Frank Stootman

Dr Frank Stootman