BOOK OF THE DAY: The Eerie Silence: Are We Alone in the Universe?By Paul Davies Allen Lane; 260pp; £20

ARE WE alone in the universe? As Arthur C Clarke once said, the answer to that question, whether yes or no, is quite staggering. It is 50 years since an astronomer called Frank Drake first pointed a radio telescope at the sky and the search for extraterrestrial intelligence (Seti) began. This shot in the infinite darkness has thus far been unsuccessful.

Paul Davies wants to believe there is more than an eerie silence out there. He is the chair of Seti’s post-detection taskgroup, charged with deciding what to do if aliens make contact. But as a scientist, he is sceptical. The scientific community is divided between those who believe life is everywhere in the universe and those who believe it is extremely rare or non-existent other than on our remarkable little planet. Davies inclines to the latter view. Life is so complex, he believes, that it is almost a fluke, a cosmic miracle that may never be replicated anywhere even if the universe is infinite.

Then again, he acknowledges he does not know because nobody knows. Seti could be the most worthwhile of endeavours, or it could be the most pointless.

What would the nature of extraterrestrial intelligence be, assuming it exists? Davies makes the interesting point that it is quite feasible for civilisations to exist without ever developing a scientific culture. Science, as we know it on Earth, would not exist without the combination of Greek philosophical inquiry and monotheism.

Davies’s fundamental point is that we should not take an anthropocentric view of possible alien life. Our civilisation is no more than 10,000 years old, a blink of the eye in cosmic terms. There could well be civilisations a million years old or even a 100 hundred million years old who are advanced in ways we cannot even begin to imagine.

We cannot even get it together to return to the Moon or go on to Mars, but generations of spacefaring aliens who have mastered interstellar travel might be traversing the galaxy for aeons. But if so, where are they?

In such a context, then, why should other civilisations use a form of narrow-band radio waves that are obsolete even by our standards? The Seti community was in retreat when the US government withdrew funding from the project in 1993, but it has since won a champion in one of the world’s richest men, Paul Allen, the co-founder of Microsoft, who has funded an array of radio telescopes. These represent such an advance on existing technologies that the gap has been compared to the difference between a 19th-century camera and its 21st-century digital equivalent.

A number of significant other developments have emboldened Seti enthusiasts. Three million have signed up to the seti@home programme, which allows the public to use spare capacity on their computers to scan radio frequencies.

Then there is the discovery of extra-solar planets in 1995 and the launch of Nasa’s Kepler mission to look for Earth-like planets around distant stars. More significant is the possibility that we will be able soon to spectrographically measure traces of greenhouse gases on extra-solar planets to ascertain if photosynthesis is taking place.

Davies’s book attempts to bridge the chasm between those who believe Seti is a colossal waste of time and those who believe it is our destiny. As he points out, we may never find alien life, but we will never know unless we look.

Ronan McGreevy is an Irish Timesjournalist and a member of Astronomy Ireland