The multiverse is a infinite or finite (but usually infinite) set of many unique Universes under a given continuous series of laws and is also the second in a series of Archverses. Uniqueness isn't mandatory, but is guaranteed due to the sensitivity of conditions during Universe formation.
Each Universe in a Multiverse, as stated above, shares in common laws of physics, systems of nature, sets of elementary particles and everything else that the laws of the parent Multiverse. However, since each Universe varies in initial conditions, the entire timeline is affected and entire cosmological structures are "reshuffled", so to speak.
We can use our own Universe as an example for ways other Universes vary in more than just timelines. For example, if the initial conditions are different enough, the ratio of matter to dark matter can be affected, the ratio between matter and anti-matter can change, and sometimes, it is possible that even constants can change by very tiny amounts, like the fine structure constant being very slightly different.
Multiverses average in size around 8 Quadrillion light-years, making our Multiverse slightly above average in diameter. Multiverses are also 4 dimensional, meaning that even though Universes are quite far away from eachother, despite not moving much, and there being copious amounts in each Multiverse, they still very rarely collide with one another and have a lot of space, whilst moving through 4 axis.
Similar to Universes, Multiverses have their own entire natural systems and structures, just like Universes. They are a byproduct of their Universes, so if a particularily strange and "mutated" Universe forms naturally within its Multiverse, it will have a strong impact on its surrounding ecosystem. However, most Multiverses have similar Universes, therefore they also appear to be homogenous.
Size of Multiverses varies and the contents are loads and loads of different Universe with different laws of nature. Multiverse can contain parallel Universes. For example, maybe there is a Universe parallel to ours where Hitler won the War, or where dinosaurs didn't go extinct or where humans aren't intelligent species at all. Maybe there are tons of Universes that are parallel to to being parallel to others. For example, maybe there is a parallel Universe that is parallel to another Universe, and thus it changes again it's reality, based on the realities of the first Universe and it's parallel Universe. Maybe this thing with parallel Universe will go on and on and on. Multiverses do not only contain Universe, but they can also contain their own space and time outside a Universe and maybe their own material. maybe even laws of nature, space, time, events, etc. completely inside themselves, but outside their Universes. It happens to the human body, the pineal gland is an organ inside the brain, inside the human body, but the spleen is also inside the human body but outside the other organs.
Upon the conception of the Proto-Xenoverse, instead of it being a perfect sphere, it becomes a tangled and disordered 6 dimensional object. When mapped onto the 3rd dimension, the 3D surface crosses itself upon random points. In reality, these points are 4D Multiverses of deformed shape.
As the Proto-Xenoverse expands and pulls these folds back, eventually becoming an actual Xenoverse, they snap and decay, turning into Metaverses, as they degenerate into the lower 5th dimension, and their crossings become the 4th dimensional Multiverses. Every fold captures the crossings that it went through, which gives the Metaverses their own Multiverses right upon birth.
The chaotic nature of the Xenoverse generates sets of laws, like encrypted random quantum fluctuations, when processed properly, which is exactly what the folds and crossings do. However, there are many other ways to do it, other than the natural everyday process, which is how most artificial Metaverses and Multiverses used to be made (new technological advancements have made this process more and more antiquated).
Multiverses in science
Max Tegmark's 4 levels
Max Tegmark, a proponent of Hugh Everett's many worlds interpretation, expanded upon his ideas from Everett's original quantum mechanics, which removes wave function collapse and asserts a Multiverse filled with Universes, where each possible observable outcome correlates to a Universe. In essence, all random quantum-state outcomes already exists, in a sort of library of Babel type way.
A level 1 Multiverse contains an infinite number of Universes of this above mentioned property.
A level 2 Multiverse is a sort of Metaverse equivelant, which contains bubbles, those being level 1 Multiverses. Level 2 Multiverses may experience spontaneous symmetry breaking, which can change physical constants.
A level 3 Multiverse is simply another break in symmetry from the lower level Multiverses.
The level 4 Mutliverse is the final in the series, containing everything describable by mathematical structures, as Tegmark believes reality is purely mathematical.
Levels 1, 2 and 3 are conceptually all equivelant.
Lee Smolin's fecund Universes
Lee Smolin, in his 1992 book The Life of the Cosmos, proposed a theory, that a black hole's collapse creates a new Universe on the "other side" of the black hole (possibly a white hole's reality / exit), with slightly changed parameters of physical constants.
In this way, Universes give metaphorical birth to other Universes, passing down their "genes", with failing Universes simply relapsing, whilst stable ones live further. This theory is also called Cosmological natural selection.
Brian Greene's 9 types
- Quilted: infinite in size, every single event happens, however, the speed of light limits us from seeing any others beyond our Universe
- Inflationary: an eternally inflating Multiverse is comprised of bubble-like pockets, which collapse to form Universes
- Brane: each Universe is constricted to a brane within a higher dimensional Multiverse, in which said Universes freely flow around, colliding on rare occassions and producing new big bangs.
- Cyclic: an extension to the brane Multiverse, where "the universes bounce back and pass through time until they are pulled back together and again collide, destroying the old contents and creating them anew." 1
- Landscape: a Multiverse comprised of a false vacum landscape creates Universes from quantum fluctuations
- Quantum: a many-world interpretation, but the Universes are created each time a wave-collapse happens
- Holographic: the Multiverse is based on the holographic principle (aka: the surface encodes the volume)
- Simulated: a Multiverse simulated on a complex computer system
- Ultimate: the ultimate Multiverse contains every mathematically possible Universe, equivelant to Max Tegmark's level 4 Multiverse
Black hole cosmology
Black hole cosmology, similarly to Lee Smolin's fecund Universes, states that Universes exists within black holes. However, fecund Universes are created upon the collapse of a black hole, effectively creating Archverses, whilst black hole cosmology brings the Universe inside the black hole upon the black hole's conception. Under this theory, a black hole can have many Universes, not just one, basically becoming a Universe cluster.
Multiverses in fiction
- Nexus of Reality
- Orrery of the Multiverse
- The Map of the DC Comics Multiverse
- Multiverse from DC Wikia
- Multiverse from Marvel Wikia
- Multiverse from Marvel Cinematic Universe Wikia
- Multi-Universe from Super Friends Wikia
- DC Multiverse from DC Universe Online Wikia
- DC Multiverse from Superheroes Wikia
- Multiverse from DC Universe Online Wikia
- Multiverse from TRwiki.net
- Multiverse from Transformers Wikia
- Le Jorino Areas - the void areas between universes
- Our Multiverse - the multiverse where we live in (actually thought by some AD people)
- Archverses - further layers of multiverses
- Omniverse - the verse consisting with every single existing thing