“Mirror, Mirror” gave Star Trek one of its most iconic alternate realities, from goateed Spock to ruthless Sulu. Here are the five best Mirror Universe characters from the classic TOS episode, ranked.

DS9’s “Crossover” expands TOS’s Mirror, Mirror with Kirk and Spock’s legacy, Intendant Kira’s tyranny, Mirror Sisko’s ...

In the season 2 episode “Mirror, Mirror,” Star Trek perfected the alternate universe trope long before Hollywood became obsessed with the unlimited franchise-expanding potential of a multiverse.

Star Trek: Enterprise season 4's "In a Mirror, Darkly" are popular episodes set in the Mirror Universe, but one actor remembers them with scorn.

We have not been able to detect dark matter yet, even though there are many aspects of the universe that suggest the existence of invisible matter. In one new theory, it is possible that dark matter ...