Science fiction is a genre of speculative fiction that explores ideas and concepts that are often rooted in science and technology, but are not yet realized in the real world. It often presents futuristic or alternative versions of society, exploring the impact of scientific advancements on humanity and the world at large. Science fiction can cover a wide range of topics including space travel, artificial intelligence, alternate realities, and time travel, and can often be used to comment on contemporary social and political issues. Famous examples of science fiction include works by authors such as Isaac Asimov, Philip K. Dick, and Ursula K. Le Guin, as well as popular franchises such as Star Trek and Star Wars.