Science fiction (often shortened to sci-fi or SF) is a kind of writing. Science fiction stories can be novels, movies, TV shows, video games, comic books and other literature. SF is often about the future. It can be about imaginary new science and inventions such as spaceships, time machines, and robots. Science fiction stories are often in a world that is very different from the real world. They can have science and tools that do not exist in reality. Science fiction stories often take place on other worlds. There are often alien creatures.