If intelligent alien civilizations exist, why has nobody ever contacted humanity? This video explores the famous Zoo Hypothesis, the Fermi Paradox, and the unsettling possibility that advanced ...

Running for over 50 years, the BBC's "Doctor Who" has had its share of iconic villains. But one of the most beloved baddies almost didn't make it into the show.

From Andy Weir's Project Hail Mary to the international masterpiece The Three-Body Problem, these alien-themed science ...