alternate universe

noun

a) A hypothetical world situated in a different dimension of space and time than the real world consisting of the universe known and experienced by human beings.

The first credible suggestion that alternate universes might exist came in the early 1950s when a young physics graduate student named Hugh Everett was toying with some of the more bizarre implications of quantum mechanics.

b) An imaginary realm, often a variant form of the real world, depicting a different way events could have unfolded or the universe could have functioned.

There are moments when he seems to be writing something on the order of Jorge Luis Borgess "Tlön, Uqbar, Orbis Tertius"—an amazing fragment about the alternate universe where every book contains its counterbook, where things become duplicated and "also tend to become effaced and lose their details when they are forgotten."

Syn: parallel universe