Science fiction is literature that explores the impact of real or imagined developments in science or technology. The basic themes of science fiction include time travel, space travel, marvelous inventions or discoveries, life in other worlds, and invasions of Earth by alien beings. Writers also examine what it means to be human, how technology might alter human relations, and the future effects of current technology. Many science-fiction writers explore ideal societies called utopias and their opposite, imperfect societies called dystopias.
Most science-fiction writers seek to convince readers that the world they have created is based on scientific principles. Some writers use material from the "hard" physical sciences, such as physics and astronomy. Others rely on the "soft" sciences, especially such social sciences as anthropology and sociology. Some writers focus on inventing believable scientific developments, while others are more interested in exploring the social consequences of scientific change. But all science-fiction writers try to present worlds that are different from the reader's world in ways that are both intriguing and understandable.
Sanders, Joe Sutliff. "Science fiction." World Book Student. World Book, 2016. Web. 16 Oct. 2016.