|Science fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically established or scientifically postulated laws of nature (though some elements in a story might still be pure imaginative speculation). Exploring the consequences of such differences is the traditional purpose of science fiction, making it a "literature of ideas". Science fiction is largely based on writing rationally about alternative possibilities. The settings for science fiction are often contrary to known reality.
Following the Age of Reason and the development of modern science itself, Jonathan Swift's Gulliver's Travels was one of the first true science fiction works, together with Voltaire's Micromégas and Kepler's Somnium. This latter work is considered by Carl Sagan and Isaac Asimov to be the first science fiction story. It depicts a journey to the Moon and how the Earth's motion is seen from there. Another example is Ludvig Holberg's novel Nicolai Klimii iter subterraneum, 1741. (Translated to Danish by Hans Hagerup in 1742 as Niels Klims underjordiske Rejse.) (Eng. Niels Klim's Underground Travels.)
The study of science fiction, or science fiction studies, is the critical assessment, interpretation, and discussion of science fiction literature, film, new media, fandom, and fan fiction. Science fiction scholars take science fiction as an object of study in order to better understand it and its relationship to science, technology, politics, and culture-at-large.
The field has grown considerably since the 1970s with the establishment of more journals, organizations, and conferences with ties to the science fiction scholarship community, and science fiction degree-granting programs such as those offered by the University of Liverpool and Kansas University.