The tagline “In space no one can hear you scream” comes from the 1979 movie Alien.
Directed by Ridley Scott, Alien follows the crew of the commercial towing spacecraft Nostromo after they investigate a mysterious signal on a distant world. The crew discovers a derelict alien ship and an unsettling collection of eggs, setting up one of cinema’s most influential science-fiction horror stories.
The tagline became famous because it captures the film’s central danger: the crew is isolated far from Earth, with no immediate help available. It also reflects the real science behind sound: in the vacuum of space, sound waves cannot travel as they do through air. The film itself uses sound inside the spacecraft, where air is present, but exterior space would be silent.
Alien premiered in 1979 and starred Sigourney Weaver, Tom Skerritt, Ian Holm, John Hurt, and Harry Dean Stanton. A common mix-up is confusing its tagline with those of later films in the franchise, especially Aliens, released in 1986.