The Fermi Paradox — Where Are All The Aliens?
YouTube
The Fermi Paradox (in short: «Why the heck haven’t we made contact with extraterrestrials yet?») is quite a beast. Last year, I had recommended this excellent explainer, if you prefer a shorter version in video, there you go.
From Weekly Filet #211, in June 2015.
💔 Some older links might be broken — that's the state of the web, sadly. If you find one, ping me.