Have you ever wondered why sci-fi films are always kind of scary? From War of the Worlds to Invasion of the Body Snatchers, all the way up to District 9, science fiction has always reflected real-life fears into an extraordinary setting. Dominic Sandbrook talks to David Tennant, Richard Dreyfuss, Steven Moffat and a host of sci-fi luminaries about how the genre's more real than you think. If you're a fan of sci-fi or just movies in general, this is definitely worth a watch.