MULTIVERSE – 6
There are different types of theories regarding the Multiverses, each of them considers the universes that compose it in a different way:
Level I: extension of our Universe: our Universe is infinite but, being infinite, it is composed of infinite parts, called Hubble Volumes, and each of them had its own Big Bang and possesses the same laws and physical constants, albeit different distribution of matter causes these volumes to be almost totally different from ours. Anyway, being infinite volumes beyond our cosmological horizon, there are infinite volumes similar if not identical to ours
Level II: universes with different physical constants: according to the Theory of Eternal Inflation, which derives from the Theory of Inflation, the multiverse that contains all universes continues to expand for eternity, but some regions stop expanding and form separate bubbles. Those bubbles are embryos of Level I universes. These bubbles can have different physical constants
Level III: Many Worlds Interpretation of Quantum Mechanics: in quantum mechanics, it is not possible to make certain predictions about some types of observations, as there is only a series of possible observations, each with a different probability of correctness and a different key for reading data. Each of these possible observations would correspond to a different universe: for example, when you roll a die, you have six different universes where a different result comes out in each. These universes would then have the same physical constants and therefore would be in a Level I Hubble volume: the only difference is that our duplicates would not live in a three-dimensional space like ourselves, but in another quantum branch of a space with infinite dimensions. Similarly, all Level II universes with different physical laws can be seen as worlds created by divisions in a Level III multiverse: according to this postulate, the multiverses of Levels I, II and III would therefore be the same
Level IV: Ultimate Ensemble: each universe is real and can be described by different mathematical structures. Abstract mathematics is so general that any theory about anything, definable in a formally correct way and independent of ambiguous terminologies, typical of human language, is a mathematical structure. This means that every conceivable Theory of Multiverses can be described at this level and contain all the others, therefore a Level V would be useless
Another classification instead describes nine types of universes:
Quilted: in a unique infinite space any possible event happens an infinite number of times. The speed of light, however, prevents us from seeing these identical areas
Inflationary: a multiverse made up of various areas where the inflationary field collapses and generates new universes
Brane: our entire Universe exists on a membrane, which is in a higher dimension where there are other membranes with their corresponding universes. These universes can interact with each other when they collide, generating so much energy that it causes a Big Bang. The membranes move in this higher dimension attracting each other by the force of gravity or forces still unknown to us, and every trillion years they collide generating cyclic Big Bangs. This type of multiverse belongs to the Strings Theory
Cycle: several membranes collide causing Big Bangs. The universe expands over time, but then the membranes are retracted from each other and, colliding again, they destroy the old universe to create a new one
Landscape: a universe based on the Calabi-Yau spaces, always part of the Strings Theory, which are spaces where the extra dimensions beyond the four we can observe, are coiled in every point of spacetime. Quantum fluctuations cause these shapes to descend to a lower energy level, creating a region with different physical laws than the surrounding space
A calabi-Yau space cross section
Quantum: whenever there is a crossroads due to the possibility of generating a new universe (it is the Many Worlds Interpretation)
Holographic: the information contained within a volume of space can be represented by a theory located on the edge of that space
Simulated: a simulation made by a complex computer system
Ultimate: it contains every mathematical possibility with the various possible physical laws for a universe (it is the Ultimate Ensemble)
PIC CREDITS
Calabi yau – Jbourjai / Polytope24