Author and producer Carl Sagan died during production. He was reportedly taking great care to ensure that science was accurately depicted in this movie.
The remark made throughout the movie by different characters, that if humans were the only life in the universe, it would "be a terrible waste of space", is a famous quote by author Carl Sagan. It references a statement by the Scottish essayist Thomas Carlyle (1795-1881), considering the potential worlds of other stars; "A sad spectacle. If they be inhabited, what a scope for misery and folly. If they be not inhabited, what a waste of space."
Carl Sagan was to cameo as a member of the committee selecting an occupant for the machine, but died before the scene was filmed.
All three acts of this movie begin with a zoomed out shot of a celestial body, immediately followed by a tight shot of Ellie's eyes. This echoes Carl Sagan's opinion that humans are a way for the universe to experience itself.
William Fichtner's character, a blind astrophysicist with enhanced hearing, is named Kent Clark, a play on the name of Superman's alter ego, Clark Kent. The character is based on a real-life blind SETI scientist, Kent Cullers.
Ann Druyan: in the upper left corner of a television divided in four different channels, with Geraldine A. Ferraro.
Ken Ralston: The senior visual effects supervisor is visible in the shot of scientists at the V.L.A. watching Ellie testify. Ralston is in the back row in the upper left corner of the frame, with a mustache and beard.