Science fiction is a genre of fiction dealing with imaginary but more or less plausible (or at least non-supernatural) content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities. Exploring the consequences of scientific innovations is one purpose of science fiction, making it a "literature of ideas".
Science fiction is largely based on writing rationally about alternative possible worlds or futures. It is similar to, but 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).
The settings for science fiction are often contrary to known reality, but most science fiction relies on a considerable degree of suspension of disbelief, which is facilitated in the reader's mind by potential scientific explanations or solutions to various fictional elements. Science fiction criteria include:
- A time setting in the future, in alternative timelines, or in a historical past that contradicts known facts of history or the archaeological record.
- A spatial setting or scenes in outer space (e.g., spaceflight), on other worlds, or on subterranean earth.
- Characters that include aliens, mutants, androids, or humanoid robots.
- Technology that is futuristic (e.g., ray guns, teleportation machines, humanoid computers).
- Scientific principles that are new or that contradict known laws of nature, for example time travel, wormholes, or faster-than-light travel.
- New and different political or social systems (e.g. dystopia, post-scarcity, or a post-apocalyptic situation where organized society has collapsed).
- Paranormal abilities such as mind control, telepathy, telekinesis, and teleportation.
Fantasy is defined as .....
Steampunk is a sub-genre of science fiction, fantasy, alternate history, and speculative fiction that came into prominence during the 1980s and early 1990s. Steampunk involves a setting where steam power is still widely used—usually Victorian era Britain—that incorporates elements of either science fiction or fantasy. Works of steampunk often feature anachronistic technology or futuristic innovations as Victorians may have envisioned them, based on a Victorian perspective on fashion, culture, architectural style, art, etc. This technology may include such fictional machines as those found in the works of H. G. Wells and Jules Verne.
Other examples of steampunk contain alternative history-style presentations of such technology as lighter-than-air airships, analog computers, or such digital mechanical computers as Charles Babbage and Ada Lovelace's Analytical engine.
Various modern utilitarian objects have been modded by individual artisans into a pseudo-Victorian mechanical "steampunk" style, and a number of visual and musical artists have been described as steampunk.