mirror universe
English
Noun
mirror universe (plural mirror universes)
- (science fiction) An alternative universe within a fictional work, separate from the universe normally depicted, where familiar characters and settings are present but in a systematically "reversed" manner, often by being evil or otherwise hostile.
- Hyponym: Mirrorverse
- Star Trek: The Original Series introduced a mirror universe in which humans had aggressively conquered parts of the galaxy rather than forming the peaceful Federation, and the setting was revisited in several of the franchise's spinoff shows.
- (physics, cosmology, rare) A hypothetical universe, a counterpart to this universe but with certain elementary particles reversed in a specific way.
- 1986 January 30, S.L. Glashow, “Positronium versus the mirror universe”, in Physics Letters B, volume 167, number 1, page 35:
- A mirror universe of fermions and forces isomorphic to but distinct from those we see couples directly to our universe only by gravity. […] Consequent effects are contrary to experiment. The possible existence of such a mirror universe is thereby excluded.