Where are the Aliens? If any civilization has evolved long enough to be capable of interstellar travel, why haven’t we seen any?
To these questions, known as the Fermi paradox, the easiest answer would be that we are all alone, or at least that no other species is advanced enough to wander in space or try to establish communication with other civilizations.
Adrian Kent, of the Perimeter Institute in Waterloo, Ontario, Canada, imagined a completely different scenario: what if our galaxy is crowded with advanced aliens, who remain quiet to avoid conflicts?
In his paper, available here, Kent says that evolutionary selection on a cosmic scale would tend to the extinction of species advertising their presence. The main driving force behind this extinction would be some sort of competition for resources, for example. Thus, intelligent species would keep their heads down to avoid the attention of some aggressive aliens: the best way to ensure survival in a cosmic scale ecosystem is to remain inconspicuous.
Are the Aliens staying quiet in their corner of the galaxy? Maybe, but there might be many other possible explanations to the complete absence of evidence of advanced alien civilizations. You could start by asking this simple question: why would aliens try to communicate via radio transmissions? After all, that is only a tiny fraction of the electromagnetic spectrum, and it can easily get altered by all kinds of obstacles. We could also imagine that we are living in an isolated area of the Milky Way, far from any other civilization. There could be many different explanations, more or less realistic.
Of course, Kent himself stresses the fact in his paper, discussing such topic as the existence of alien civilizations is pure speculation. Anyway, this scenario doesn’t seem implausible, and could be an answer to the problem raised by Fermi, among others.
Finally, whatever the answer to the Fermi paradox is, this new hypothesis might be worth considering. Perhaps, we should remain quiet?