College of Arts, Humanities and Social Sciences

Lecture 3: Meeting the Aliens: Galactic Hide and Seek

If evolution is predictable in its outcomes on this planet then like any other science the results should apply universally.

This remains the case even if extra-solar planets, of which more than 150 have been detected, have surface conditions very different from those of the Earth. This is not to say all planets are potentially habitable, in fact the great majority are probably not and there are reasons to believe that most planets (and moons) that house life (if there are any) are roughly earth-like.

In any event evolutionary convergence can give us some very strong hints as to what we would expect to find, even in planets that are, for example, tidally locked to a red dwarf star, possess a much denser atmosphere, or have super-oceans hundred of kilometres deep. So we can make reasonable predictions as to how the aliens will sense their environment, how they will move, what sort of social systems they will construct (including almost certainly one of the great evolutionary success stories in the form of eusociality, a system that has evolved many times in insects and, incredibly, even in mammals), how they will evolve agriculture, and, yes, also intelligence.

Yet here we run into a major difficulty. If, as I would argue, intelligence is as evolutionarily inevitable as camera eyes or eusociality, then is it not very strange that to date the Search for Extraterrestrial Intelligence (SETI) has drawn a complete blank. No signals, no sign of being visited. The famous Fermi paradox (“Where are they?”) is a hint that the universe may be very far from being what it seems.

This lecture has been recorded on MP3: