Why haven’t we encountered aliens yet? The answer could be climate change | IFLScience January 11, 2015Posted by sandyclaus in Drake Revisited.
Enrico Fermi, when asked about intelligent life on other planets, famously replied, “Where are they?” Any civilisation advanced enough to undertake interstellar travel would, he argued, in a brief period of cosmic time, populate its entire galaxy. Yet, we haven’t made any contact with such life. This has become the famous “Fermi Paradox”.
Various explanations for why we don’t see aliens have been proposed – perhaps interstellar travel is impossible or maybe civilisations are always self-destructive. But with every new discovery of a potentially habitable planet, the Fermi Paradox becomes increasingly mysterious. There could be hundreds of millions of potentially habitable worlds in the Milky Way alone.