Cosmos
 

Where are All Those Aliens?

Most scientists assume that the universe must be populated with innumerable alien intelligences and civilizations—after all, there are billions of galaxies each with billions of stars and planets—we humans can't be so special. The universe should be teeming with life. OK, that's the argument. So where are they? How come there's zero evidence?

 

Where are All Those Aliens?

Discussion