The 2011 film Another Earth, directed by Mike Cahill, explores very human questions against an improbable backdrop. Artists Public Domain/The Kobal Collection hide caption

itoggle caption Artists Public Domain/The Kobal Collection

Author Richard Matheson's science fiction stories included The Shrinking Man, I Am Legend, and numerous other movie and TV scripts, including episodes of The Twilight Zone. Archive of American Television hide caption

itoggle caption Archive of American Television

There's always a girl and there's always a gun: the Hero-Blaster used by Harrison Ford's character in the movie Blade Runner. The gun was up for auction in 2009. Mark Ralston/AFP/Getty Images hide caption

itoggle caption Mark Ralston/AFP/Getty Images