Star Trek Expanded Universe

Hundreds of thousands of USS Enterprise's from parallel universes

A parallel universe (or quantum universe) is a universe separate to our own universe, running "parallel" to our own. It is sometimes known as an alternate universe or alternate reality.


Several theories exist on the creation of parallel universes. It is generally agreed one different choice made by one being in our own universe spurs off another parallel universe, differentiating it from our own universe.

Considering this theory, an infinite number of parallel universes exist, separated by some kind of barrier (possibly vibrational or "quantum"). These parallel universes are sometimes known as quantum universes, quantum realities or quantum states.

Alternate timelines are not the same as parallel universes, as time travel within the same universe creates an alternate timeline if history is altered as a consequence. However, an "uncorrected" alternate timeline may in fact solidify into a stable quantum reality if the changes are significant.

Prime universe[]

See also: Prime universe

In contrast to parallel universes, the prime universe (or primary universe) is the originating universe, or "our own", in which some alternate realities have been known to pair off from, or, the mirror universe and other parallel universes, have run parallel to. (Star Trek, TOS: "Mirror, Mirror", Star Trek Online)

The prime universe has been known to separate into other continuities, most notably: the Online timeline and Destiny timeline.


USS Enterprise-D security chief Worf experienced several parallel universes in 2370. In one of these, Cardassian and Bajoran roles were inverted. (TNG: "Parallels", Sigils and Unions: Catacombs of Oralius)

Mirror universe[]

See also: Mirror universe

The crew of the USS Enterprise were amongst the first Starfleet crews to experience another quantum reality with the first crossover to the mirror universe in 2267. (TOS: "Mirror, Mirror")

Borg-infested universe[]

In an alternate timeline, in 2370, when the hundreds of thousands of Enterprise-D's from parallel universes were brought into one, a badly-damaged Enterprise attempted to fire on Worf's shuttle. This Enterprise originated from a quantum universe in which the Borg were "everywhere". This Enterprise was destroyed in this timeline. (TNG: "Parallels")

With the reset of the timeline through Worf's efforts, it is likely this Enterprise was restored as well.

In 2380, the USS Hijinx was unintentionally sent to this universe after an alien ship quantum-altered Saturn's rings. The Hijinx was quickly intercepted by a Borg cube, the ship destroyed and its crew assimilated. In 2390, the senior staff and some of the crew of the Hijinx were in assimilated-San Francisco, Earth, when they were separated and saved from the collective by a virus injected by the Borg-infested universe's Phoenix-X. (Star Trek: Phoenix-X: "Hijinx")

In 2410, in an attempt to evacuate an entrapping layer of subspace, the Phoenix-X of the prime universe fired an inverse tachyon pulse which happened to converge with two other pulses from other timelines. One of the others was from the Phoenix-X of the Borg-infested universe, in which Ensign Dan was Captain. (Star Trek: Phoenix-X: "Nightmare Anomaly")

Gender-bent universe[]

In 2261 of Nero's alternate reality, the USS Enterprise encountered an anomaly which enabled an encounter with an Enterprise from this universe where the males of the prime universe were females and vice-versa. (TOS comic: "Parallel Lives")

In 2410, Captain Oroku Seifer and Kayl of the prime universe were accidentally transported to the gender-bent universe version of the Phoenix-X, where they assisted in saving the ship from an attack by DiaMon Cida of the Jade Fox. (Star Trek: Phoenix-X: "The New Frontier, Part II")

The Star Trek Online: Literary Challenge "Gender Swap" covered fiction in which player's characters were met with their own gender-opposites from this universe.

Tribble space[]

In 2410, Captain Oroku Seifer and the USS Phoenix-X were accidentally sent to a universe where spaceborne tribble filled most of known space. It was under rule from Troblor, and was coined as "tribble space" by Armond. There, Troblor made claim to seeding the prime universe with tribble in an attempt to fill its known space. ("The New Frontier")

It was reported that the Tholian Assembly had outposts in Tribble space. ("From Hell's Heart...")


Continuities can also be considered parallel universes, depending on perspective, but they differ in that they may involve a single or more fan series', or a rich vein of licensed source material, devoted them (i.e. published novels, short stories, video games, etc.).

Destiny timeline[]

The Destiny timeline takes place in the prime universe and encompasses events and settings from novels that are connected to novel miniseries Star Trek: Destiny, Star Trek: Typhon Pact, and others.

Online timeline[]

The Online timeline takes place in the prime universe and encompasses events and setting from the game Star Trek Online and fiction related to it, including The Needs of the Many and Star Trek Online short stories.

Nero's alternate reality[]

Main article: Alternate reality


Main article: Shatnerverse


See also[]

Many Star Trek fan-fiction venues are, by their nature, set in parallel/alternate universes. Following are some examples:

Parallel mirror universes:

There are also those series which are set in the primary universe but crossover into parallel universes:

  • Star Trek: Special Operations
    • Special Ops' fifth part, 'Reflections' sees the crew transported into an alternate universe where the Borg are running rampant.

Crossovers with other franchises, like 'Doctor Who or Star Wars, often involve characters from one series traveling to a different quantum reality where the other franchise exists.

External links[]