Science fiction (sometimes called sci-fi or just SF ) is a genre of speculative fiction that typically deals with imaginative and futuristic concepts such as advanced science and technology , space exploration , time travel , parallel universes , and extraterrestrial life . It has been called the " literature of ideas ", and often explores the potential consequences of scientific, social, and technological innovations . [1] [2] Science fiction, whose roots go back to ancient times , is related to fantasy , horror , and superhero fiction, and contains many subgenres . However its exact definition has long been disputed among authors , critics , and scholars . Science fiction literature , film, television, and other media have become popular and influential over much of the world. Besides providing entertainment , it can also criticize present-day society , and is often said to inspire a " sense of wonder ". [3]