Genre is any style or form of communication in any mode (written, spoken, digital, artistic, etc.) with socially agreed-upon conventions developed over time. The need to understand what movie is for whom persists despite the blurring the genres in modern film. This paper analyses part of Susan Sontag’s essay “The Imagination of Disaster”, which deals with the structure of sci-fi movies, and Vivian Sobchack’s “Images of Wonder: The Look of Science Fiction”, which deals with the iconography of science fiction, through three movies – Ridley Scott’s Alien, Andrei Tarkovsky’s Solaris and Howard Hawks’ El Dorado. Beyond the structural elements revealed by Sontag, or the iconographic approach of Sobchack, audio is found to be a far reliable element that defines science fiction movies. Keywords: Science fiction, Alien, Solaris, western, genre, audio