In the most basic terms, the difference between science fiction and fantasy is that, science fiction can be defined as what could happen and fantasy as that could not. Science fiction is a sub-genre of fantasy that is explained in scientific and technological language. Sci-fi is traditionally characterized by advanced technology, experiences with alien beings, and explorations of new planets; while fantasy tends to revolve more around magic and quests. Science fiction pushes your imagination to the limit, but fantasy goes beyond that.
Attacks from Martians, time travel, interplanetary travel and the impossible are possible within the realm of science fiction. Most of the science fiction definitions revolve around the idea that science is reality, and how that science effects the realty it is in. It is meant to illustrate the relationship between cause and effect representing a society in chaos, disturbed by the scientific matter, which may or may not be based in fact.
This is a bit complex but what it says that science fiction is meant to illustrate the effect of improbable (within scientific plausibility) against the setting it is in. It studies the resulting events that did not happen, may have happened, or have not yet happened from a rational perspective, mostly interested in the impact on the people involved. Science fiction is a form of fantastic fiction that exploits the imaginative, and profound perspectives of modern science. It differs from the fantasy genre to which it is commonly compared as it is meant to respect the limits of scientific possibility.
Fantasy and science fiction go together as closely as fish and chips, with the difference that while chips is not made out of fish. When we imagine the whole of literary fiction as being located within a great circle drown on a piece of paper;...