Where are all the aliens?

The Fermi paradox

by Marnanel Thurman

If the sky's the limit, why do we never hear from aliens? There are billions upon billions of worlds out there, but we've never heard a word from anyone else. Why not? There are no certain answers to this question, known as the Fermi Paradox, but there are plenty of suggestions: Wait But Why discusses the possibilities. A good read.