Mirror universe

The Mirror Universe is an alternate universe close enough to our own that most individuals and places do have a counterpart there, but often in entirely different situations. The universe was so named because many people and places seemed to be the exact opposites of their "normal" selves in this universe.

Overview
The mirror universe is a parallel universe where the patterns of events move in similar manners, but the intentions and characterizations are different, so the people of the mirror side will always remain (and always have been) skewed versions of their "normal" counterparts, so no true point of divergence exist, as the two realms move in a parallel manner with the Mirror Universe simply having much more violent roots.

In this reality Earth ran the brutal Terran Empire instead of a benevolent Federation. First seen in the TOS episode "Mirror, Mirror," and visited in several other episodes, comic books, and novels, it has become a fan favorite. These stories include Fragile Glass, a one-shot story by Marvel Paramount Comics, The Mirror Universe Saga, an eight-part graphic novel by DC Comics set after Star Trek III: The Search for Spock, Dark Mirror, a novel Diane Duane wrote before DS9 aired the mirror-universe episodes, a Mirror Universe Trilogy written by William Shatner and Judith and Garfield Reeves-Stevens, and Dark Passions, a two-parter written by Susan Wright. Michael Jan Friedman featured people from the MU in Stargazer: Three.

Point of Divergence
Various theories have been put forth to explain how the Mirror Universe came to be. Dark Mirror had Earth's history take a darker turn starting with the end of Homer's Iliad, where Achilles kills King Priam instead of showing one moment of humanity. Khan Noonien Singh and the other supermen won the Eugenics Wars, but then wiped each other out. The Vulcans were also militaristic as there was no Surak. In Dark Passions the Bajorans and Trill had empires until they were conquered by Earth, and the Klingons celebrate the victory of Molor over Kahless.

The Mirror Universe Trilogy had Earth's and Vulcan's history the same until First Contact. In the MU Zefram Cochrane warned the Vulcans about the Borg, and humans and Vulcans formed a militaristic alliance to wipe out the Borg, after which they became the Empire. The Mirror Universe Saga had the Empire come about because the Romulans conquered Earth and enslaved humans for almost a decade. When Earth overthrew the Romulans it embarked on a program of conquest itself and became the Terran Empire.

Canonical history of the MU has recently been given in the Enterprise episode, "In a Mirror, Darkly", where it was revealed that in this universe, first contact between Vulcans and Humans took place as it did in our universe. However once the Vulcans landed, instead of welcoming them with open arms, Zefram Cochrane shot the first Vulcan to step onto "Terran" soil and the "Terrans" proceeded to raid the Vulcan ship. The gun used by Zefram Cochrane later would come into the possession of Jonathan Archer, who wondered what would have happened had Cochrane not "turned the tables on the Vulcans' invasion force." With advanced Vulcan technology now at their disposal, the Terrans were able to expand the "Terran Empire" and conquer other worlds, including Vulcan.

The Continuum
The Mirror Universe, like all parallel timelines, is believed to lie parallel to the Federation Universe in a six-dimensional continuum: three dimensions of space, and three of time. The dimensions of space (height, width, and depth) are familiar. The linear motion of time (past-present-future) can be considered one "dimension" of time. Time's other dimensions are made up of probability fields that are the "height" and "width" of time. In essence, these temporal dimensions encompass every possible past, present, and future that could exist, and does, "elsewhere" in the continuum.

In these higher temporal dimensions lie a potentially infinite number of timelines, running parallel to the familiar Federation Universe. The amount of divergence between universes - essentially the difference between their quantum signatures - determines how "far apart" they are in temporal terms. The Mirror Universe lies quite "close" to the Federation Universe in a dimensional sense, one of the reasons it was the first parallel dimension encountered by visitors from the Federation Universe.

Quantum Signatures
All matter in a particular timeline resonates on a quantum level with a unique "signature", which is constant and cannot be altered by any known process. This quantum signature is normally of little interest, since it is common to everything in the universe. However, objects from outside the universe have a different quantum signature. This includes people and objects from a parallel dimension. A quantum scan can determine whether or not something is from the same universe as the scanner. If the quantum signature of the subject's home dimension is known, then it can also be identified.

Note that at present the quantum signature of the Mirror Universe is not widely known in the Federation and vice versa, so correctly identifying the universe of origin for either requires some time and a computer records search.

Quantum Flux
Although the quantum signature of matter cannot be altered by any known means, it is possible to place matter in a state of quantum flux. This causes the affected matter to become "unstuck" in the spacetime continuum, shifting "sideways" through time into another dimension. Transporters have the potential to place matter into a quantum flux state, and use a component known as a quantum resonance oscillator to keep the matter stream in the correct quantum state with relation to the rest of the universe, preventing it from going into quantum flux. As we will see, a failure of the quantum resonance oscillator can lead to quantum flux, along with a number of other high energy phenomena.

Quantum Inversion Field
The Mirror Universe is unusual, even for a parallel dimension. Most parallel dimensions known to Federation science are what might be termed alternate histories. They diverge from known Federation history at a particular place in space-time, known as the divergence point. From that moment on, they follow their own history, but before the divergence point, they are identical to the Federation Universe, save for a difference in quantum signature.

Some parallels appear to have diverged from Federation history so long ago that it is difficult to determine the divergence point. These parallels are quite different from the Federation Universe, up to and including vastly different life forms evolving on Earth, Vulcan, and other planets of the galaxy. The further the divergence point is from the Federation present, the less likely it is for the parallel to have anything even remotely resembling Federation Universe history.

The Mirror Universe appears to be the exception. Although Mirror Universe history is quite different from Federation Universe history, going back centuries at the very least, many aspects of the Mirror Universe are remarkably similar to the Federation Universe, including the presence of certain individuals in both universes. For example, when Captain Kirk and his crew first encountered the Mirror Universe, they accidentally beamed on board an Enterprise that was an almost exactly duplicate of their own, down to the presence of an acid stain Dr. McCoy recalled from his own sickbay. Although the Terran Empire differed radically from the Federation in terms of politics and culture, it still had many of the same people.

With a history that diverged even decades previously, much less centuries, the odds of the Mirror Universe having a duplicate Enterprise, with an almost identical crew, are astronomical. The odds of there being a Benjamin Sisko and a duplicate crew of Deep Space Nine nearly a century after Kirk verges on the impossible. The events described by Intendant Kira, including the fall of the Terran Empire at the hands of the Alliance, should have so scrambled the human gene pool that Sisko and company should never have been born. And yet they exist in the Mirror Universe, along with duplicates of many other people from the Federation Universe. Why?

The exact answer is uncertain, but Federation scientists who have studied the phenomenon of the Mirror Universe have offered a theory. They suggest that the Mirror Universe represents some kind of "quantum inversion field," an almost literal "mirror" of the Federation Universe. The inversion field creates a universe that duplicates the Federation universe on a macroscopic scale, while altering events and personalities on a smaller scale. Take the example of looking at your reflection in a mirror. The image looking back at you appears nearly identical to you, but if you were to hold up a book or a sign, the writing in the mirror appears backwards. So it is with the Mirror Universe. The large-scale things are nearly the same: planets, people, and even starships and space stations, but many of the details, the "writing" of the universe, are the opposite of what they are in the Federation Universe.

This "quantum inversion field" theory implies a strong relationship between the Mirror Universe and the Federation Universe, a kind of interdependency. Events in the Federation Universe may serve to dictate or at least influence events in the Mirror Universe. It may be that the Mirror Universe is only that, a reflection of the Federation Universe. If the Federation Universe was destroyed, the Mirror Universe might cease to exist as well. Of course, it is equally possible the Federation Universe is actually the reflection, and the Mirror Universe is the "real" one, or that they are both equally "unreal," reflections of some "higher" reality. Still, the strong relationship between the two realities on the quantum level seems to be what makes travel between them relatively easy compared to other quantum phenomena.

Quantum Mirroring
One result of this theory about the nature of the Mirror Universe is what scientists call "quantum mirroring." This essentially describes the fact that events and individuals often appear duplicated in both universes despite the larger-scale differences between them. For example, the lives of individuals from both universes are often extremely similar, even down to the smallest details, despite larger difference in personality and attitude.

Dr. McCoy's acid stain is a prime example. Although the Dr. McCoy from the Federation Universe was clearly a very different person from his Mirror Universe counterpart (who was described as "weak-willed" and prone to drinking excessively) both men experienced an identical accident that left an identical stain on their respective workbenches. Likewise, the Benjamin and Jennifer Sisko from the Federation Universe and their counterparts from the Mirror Universe were both married, although the Federation Jennifer died during the Borg assault on Wolf 359, while the Mirror Jennifer separated her husband and continued her work as a scientist. The list of similarities goes on and on.

Quantum mirroring somehow "synchronizes" certain events between the two universes. Scientists are uncertain how this happens, or why certain events are mirrored almost exactly, while others are distorted or altered, and some events are not mirrored at all. They speculate that it may be possible to influence the events in the Mirror Universe through a greater understanding of the phenomenon, but to what degree remains unknown.

Quantum Flux Shifting
The only known means of travel between the Federation Universe and the Mirror Universe involves putting a subject into a state of quantum flux matched to the particular quantum resonance of the other universe. The affected matter shifts out of one universe and into the other. Returning to the original universe is a matter of once again placing the subject in a state of quantum flux and matching the resonance of the original universe. This is somewhat easier, since the subject's natural quantum signature always matches that of the subject's home universe.

This technique was first discovered accidentally by the crew of the U.S.S. Enterprise (NCC-1701) in 2267, when an ion storm over the planet Halka caused a failure of the quantum resonance oscillator in the ship's transporter system. When members of the bridge crew attempted to beam aboard, they entered a state of quantum flux and shifted into the Mirror Universe. At the exact same moment, the bridge crew of the ISS Enterprise shifted into the Federation Universe. The two crews being on (essentially) the same mission, and beaming back to their vessels at the same moment is another example of the quantum mirroring between the two universes. Enterprise Chief Engineer Montgomery Scott was able to reverse the quantum flux process to return the crew to their home universe, while at the same time the crew of the Mirror Enterprise was returned to their universe.

Although some scientific investigation of the Enterprise mission took place, the Federation Council decided on a policy of non-intervention in the Mirror Universe. Although Captain Kirk's actions in the Mirror Universe could be interpreted as a violation of the Prime Directive, the Council decided that the Directive did not specifically cover interference in the history of a parallel universe. Captain Kirk's actions were overlooked, and the definition of the Prime Directive was extended to include the Mirror Universe. Research into the nature of the Mirror Universe has been necessarily limited as a result.

Quantum Flux Transporter
The primary means of access between universes remains the quantum flux transporter. By modifying the quantum resonance oscillator of a standard transporter system, it is possible to place the matter stream in a state of quantum flux, shunting objects into a different universe during the re-materialization process. Targeting the transporter requires the quantum signature of the target universe; otherwise the subjects may become lost in the space-time continuum.

Apparently, the Terran Empire (and later the Klingon-Cardassian Alliance) modified the quantum resonance oscillators of their transporters systems to make quantum flux transport impossible, most likely to keep people from fleeing their grasp by escaping into parallel timelines. The existence of the Federation Universe was kept secret from most people, out of concern that knowledge of parallel timelines might inspire hope and rebellion in subject populations. Still, residents of the Mirror Universe have modified transporters to function as quantum flux transporters, and have used them to visit the Federation Universe.

Wormholes
Normally wormholes provide a "shortcut" to a different point in spacetime. Thus far, all the wormholes known to the Federation connect different points within the same timeline; that is to say wormholes appear limited to the three dimensions of space and the linear dimension of time, rather than extending into the "sideways" temporal dimensions. However it is theoretically possible for a wormhole to connect two parallel timelines. Such a wormhole would most likely be short-lived, formed by high-energy interactions in the vicinity of strong subspace or gravitic forces (such as an active warp field or possibly a black hole). A ship could use an interdimensional wormhole as a means of traveling from one universe to another.

Experience has also shown that a resonant warp field applied to a normal wormhole can cause anything inside the warp field to enter a state of quantum flux, shifting it between universes. This occurred in 2370, when a Federation runabout carrying Major Kira Nerys and Dr. Julian Bashir suffered a warp malfunction inside the Bajoran wormhole, sending the ship and its crew into the Mirror Universe. By modulating the warp field exactly, it is theoretically possible for a ship entering a wormhole to travel to a parallel universe intentionally.

Quantum Singularities
A quantum singularity is a point of incredibly intense gravity, so powerful that neither light nor normal matter can escape from its pull. The gravity emitted by a quantum singularity can stress local spacetime in such a way as to cause spatial and temporal distortions. Chroniton particle emissions are common around quantum singularities, which may interact with subspace to cause unusual phenomena. The Romulans use a forced quantum singularity as a power source for their starships rather than a Federation-type antimatter engine.

An encounter with a quantum singularity in deep space, or the failure of an artificial singularity like those found aboard Romulan vessels, could accidentally induce a state of quantum flux. For example, a battle between a Federation and Romulan vessel could lead to the formation of a quantum fissure, or simple phase shift both vessels out of normal spacetime into another universe. Returning in such a case would require the cooperation of both vessels and crews.

A vessel might be able to channel the energies of a quantum singularity, in conjunction with a warp field, to place matter in a state of quantum flux. The Klingons and Romulans experimented with a similar technique to shift a cloaked vessel out of phase with ordinary matter, not only making the vessel completely undetectable by conventional scanners, but also allowing it to pass through ordinary matter unharmed. All the experiments ended in disaster and were abandoned by both Empires. Two experimental phase cloak vessels vanished entirely, never to be seen again. It is possible they were phase shifted out of the universe entirely and into a parallel universe (although not the Mirror Universe, apparently).

Quantum Fissures
A quantum fissure is a weak point in the spacetime continuum where different parallel timelines come in contact. It can be thought of as a kind of "quantum keyhole" between different universes. Normally, quantum fissures are extremely small, and short-lived, of little concern to anyone. However, certain high-energy subspace interactions, particularly warp fields, can cause quantum fissures to grow and de-stabilize, creating a more volatile interface between dimensions. Exposure to such a quantum fissure can place objects in a state of quantum flux, causing them to shift between different parallel universes.

A quantum fissure could theoretically be used as a means of travel between parallel universes, but a means of controlling the fissure and choosing a destination would be required. Alien technology - like that of the Iconians - might employ artificial quantum fissures as a means of dimensional travel.

Alternate Modes of Transport
There are a number of other possibilities for travel between parallel universes.

Warp Fields
Warp field and warp drive technology is an integral component to many of the modes of interdimensional travel above. Warp fields have the ability to alter the properties of local space-time and the Federation's understanding of the relationship between warp fields and reality is in many ways only beginning. A static warp bubble once created an alternate reality, so it is quite possible an application of warp fields might provide a means to travel to parallel universe.

Warp fields mixed with exotic phenomena like quantum fissures, singularities, cosmic strings, and so forth create a recipe for sending a starship nearly anywhere (and anywhen), including into a parallel like the Mirror Universe. Getting back may involve duplicating the circumstances of the original accident - often involving a short-lived interstellar phenomenon, like an unstable wormhole or quantum fissure.

Time Travel
Time travel normally involves moving along the linear dimension of time, but it is possible some methods of time travel could - intentionally or accidentally - permit movement "sideways" through time into a parallel universe. Experiments involving time travel and the nature of time could open a "window" into the Mirror Universe, or simply catapult the scientists into the Mirror Universe altogether, with or without a means of getting back home.

Mirror Universe episodes

 * ENT:
 * "In A Mirror Darkly"
 * "In A Mirror Darkly, Part II"
 * TOS: "Mirror, Mirror"
 * DS9:
 * "Crossover"
 * "Through the Looking Glass"
 * "Shattered Mirror"
 * "Resurrection"
 * "The Emperor's New Cloak"

Mirror universe novels
Through a Glass Darkly RPG may have been written up while Last Unicorn Games still held the rights to Trek RPGs. See here.