The mystery of the silent aliens - CultureLab - New Scientist
In The Eerie Silence, Paul Davies - who makes a living tackling the biggest questions of life, the universe and everything - begins with the assumption that the universe should be full of life. There are more stars out there than there are grains of sand on all the Earth's beaches, and now that more than 400 planets have been found orbiting other stars, we can be almost certain that most stars have planets. Surely our Earth is not unique.
But while the odds against life seem to be shortening, thanks to those exoplanets, it is now pretty clear that our part of the galaxy, at least, is not a hive of obvious alien activity. The cosmos may be buzzing with life, or even with intelligence, but it is not Star Trek out there.
Perhaps we are looking in the wrong way, muses Davies. At the core of his rather wonderful book is a list of imaginative alternatives to the current focus on radio signals from nearby stars - a search that is, he claims, shackled by anthropocentric assumptions and innate conservatism, and ripe for a shake-up.
Rather than expecting to stumble upon a high-power radio transmission aimed directly at Earth, we might look for ghostly neutrino signals or messages encoded in the otherwise clockwork light flashes from pulsars. We should also be on the lookout for alien life forms - or their probes - closer to home, and search for circumstantial evidence that aliens are here, or at least were here, perhaps millions of years ago. Beacons in the asteroid belt, perhaps, bits of ancient machinery left on the moon, or suspicious polygonal craters. Maybe ET will tune into the internet: the ieti.org website has been set up to allow them to do exactly that.