In the season 2 episode "Mirror, Mirror," Star Trek perfected the alternate universe trope long before Hollywood's multiverse obsession.

Pick up any science fiction book from the 1960s, and you’ll find parallel dimensions explained through magic portals or mysterious machines that work “just because.” Today’s readers want stories that ...

Hints of a mirror cosmos have a way of gripping the imagination, and recent chatter about “first proof” of a parallel universe has pushed that fascination back into the spotlight. Behind the viral ...