Multiverse

The Multiverse is the entirety of existence and reality: this universe, other universes, and everything in between.

One of the fundamental concepts of a multiverse is that there are a number of similar but different realities: but what exactly is a reality? What is an alternate reality, and is it anything like an another universe, another timeline, or another dimension?

Alternate Dimensions

Within each universe, there are a number of different dimensions. This term can have more than one meaning, however. In one sense, a dimension is a physical characteristic - length, width, depth, time - that defines an object that exists in spacetime. Just as a seemingly two-dimensional circle on a sheet of paper has an unseen third dimension ("thickness"), it is possible for objects to have dimensions beyond the three that humans typically perceive, like hypercubes and hyperspheres. These higher dimensions are usually understood only through mathematics, as part of complicated theories to understand gravity, the fundamental forces, the shape of the universe, and so on.

Separately, but similarly, the term can also refer to Subspace and Hyperspace, two regions that exist outside of normal spacetime. If the universe is imagined as an orb of water, then normal spacetime would be the surface of the orb, subspace would be the water inside the orb, and hyperspace would be the air above the orb. Conceptually, a three-dimensional ship sailing on the surface of that orb that was trying to get from one side to the other would have to travel around the circumference of the orb, made longer by the waves and ripples caused by gravity that distort and stretch that surface. However, from an outside perspective, the shortest path from A to B would seem to be a straight line through the orb: this is the premise behind a wormhole, a path through subspace that connects two points on the "surface" of space. In the same analogy, travel through hyperspace would be equivalent to the ship taking off and flying to the other side, reaching its destination much faster because it does not have to contend with the "surface tension" presented by the laws of physics. Hyperspace is the origin of tachyons, faster-than-light zeta-particles (𝜻) that oscillate with the frequencies of the emotional spectrum, convey the Speed Force, and facilitate the physics-defying travel of Hyperdrive technology. Subspace meanwhile is the origin of dark matter and dark energy, consisting of invisible omega-particles (𝛀) that influence the motion of galaxies, the expansion of the universe, and facilitate the reality-warping abilities of many Metahumans.

In addition to alternate spacial dimensions like Subspace and Hyperspace, there are also alternate metaphysical dimensions. These are realms that have the same physical/spatial coordinates as normal spacetime, but function as different planes of existence, resonating with different metaphysical energy. Chief among them is The Red, a bloody hellscape connecting the energy of living animals, associated with demons, blood magic, and the Lords of Chaos; The Green, a verdant energy field connecting plant life, associated with wild magic and fey creatures; and The Blue, the structured and aetherial domain of arcane magic and the Lords of Order. In metaphysical parlance, Subspace and Hyperspace are sometimes known as The Black and The White respectively.

Almost every "other dimension" within the confines of a specific universe falls within one of those five alternate dimensional spaces. The Phantom Zone, Purgatory, The Dreaming, and the Vanishing Point are pockets of reality within Subspace, and the Speed Force is synonymous with Hyperspace, while Greek underworld of Tartarus is located within The Red, the Gaelic Otherworld and the "Hollow Earth" realm of Skartaris are located within The Green, and the mystical isle of Avalon can be found in The Blue.

Alternate Universes

A universe is a discrete bundle of all the various dimensions that make up a particular version of reality. If the universe is an orb of water, then the multiverse is filled with numerous orbs of water, each one similar but different. Alternate Universes have the same dimensions, the same size, composition, and general structure, but are found at different coordinates within the multiverse, and have subtle differences due to the ripples and deviations that take place on their spacetime surface. Any given point, molecule, person, or event may have a direct corollary (or "doppelganger") in an alternate universe, but just as easily a universe's structure might be arranged in a completely different and unrecognisable configuration. From a humanocentric viewpoint, these alternate universes are often referred to as Alternate Earths. Theories differ on how many alternate universes could and do exist. Some calculations project that there are only 52 stable sets of multiverse coordinates, while other theories predict that there could be infinite Earths.

Because Hyperspace exists "above" each universe, the respective Hyperspaces of alternate universes intersect and overlap. Thus, it is possible to use Hyperspace - the Speed Force - to "breach" from one alternate universe to another. Navigation between adjacent universes - such as between Earth-1 and Earth-2 - is relatively easy, with travel becoming increasingly difficult the more intervening universes one has to slide past.

Earth-1

The prime/correct universe, from our perspective.

Earth-2

A multiversally "close" alternate universe, where major historical events are mostly similar to Earth-1, but some personal events and circumstances differ: such as certain births, deaths, relationships, and genders.

Earth-3

An alternate universe where Earth-1's heroes and villains have switched places.

Earth-Ø

A reality where the events of Earth-1 are regarded as fictional. (ie. the "real" world)

Alternate Timelines

An alternate timeline is created when time travel is used to alter the events of the past, rewriting the history that follows. Alterations to the timeline are limited to the universe in which they occur - changes to the past of Earth-1 do not affect the events of Earth-2 - and take time to propagate across the spacetime continuum, leaving a window of opportunity for those alterations to be corrected, either by other time travellers or by entities such as the Speed Force. In addition to complete alterations to the timeline, other problematic temporal anomalies exist: such as anachronisms, which are temporal flotsam and jetsam displaced from their native point in time; and time remnants, objects or persons that originate in a version of time that no longer exists.

Time travel is usually achieved in one of two ways: travel through the "Temporal Zone" (a wormhole through subspace, the two ends of which have different time coordinates), and travel through the Speed Force - both regions that exist outside of normal spacetime. When travelling (or communicating) between universe, it is possible for a chronometric misalignment to occur, causing the respective histories of the two universes to not quite correlate, and leading to a glimpse of or an arrival at a point in another universe's past or future.

Timeline A

Refers to the current timeline of Earth-1. It differs from the version of history familiar to Booster Gold, a time remnant from Timeline B. Based on current information, most of which comes from the time travelling speedster Impulse, this timeline will culminate in a global apocalyptic event at some point after 2040, leading to a dystopian war-torn future nicknamed Warworld. Because of this, many important eras of future history - such as the 25th Century of Booster Gold and Reverse-Flash, or the 31st Century of the Legion of Superheroes - never happen, leaving a handful of displaced survivors as time remnants. Due to the presence of Impulse - and potentially other time travellers - however, the future of Timeline A is in flux, with A.R.G.U.S. unofficially intending to take steps to alter the projected outcome.

Timeline B

Refers to the native timeline of Booster Gold. It differs from Timeline A in several significant details, ranging from major historical events to births and deaths, genetics, and even the existence or non-existence of prominent individuals. For example:

• Connor Kent is a clone of Superman and Oliver Queen in Timeline A, whereas in Timeline B his human DNA comes from Lex Luthor.
• Barry Allen and Iris West-Allen have a daughter (Nora) in Timeline A, who does not exist in Timeline B.
• Lar Gand of Daxam is rescued from his crashed ship by A.R.G.U.S. in Timeline A, rather than Superman, preventing the future in which he becomes Mon-El.

Timeline B is essentially the canon continuity of DC Comics. It represents how DC characters "should" be, versus the reimagined versions of TheHolo.net.