Multiverse theory differences

Question

ok ive herd of m theory and i herd that there are infinite universes all with a diffrent law of physics so does that mean that in another universe i could be one atom less then i am now or one more or two more etc

Answer 1

The bizarre thing about the many world's interpretation is that it cannot occur if you do not solve the math using perturbation theory. I think you have to be very suspicious of a theory that disappears if you do the sums differently.

Answer 2

The multiverse (or meta-universe) is the hypothetical set of multiple possible universes (including our universe) that together comprise all of reality. The different universes within the multiverse are sometimes called parallel universes. The structure of the multiverse, the nature of each universe within it and the relationship between the various constituent universes, depend on the specific multiverse hypothesis considered.

Multiverses have been hypothesized in cosmology, physics, astronomy, philosophy, theology, transpersonal psychology and fiction, particularly in science fiction and fantasy. The specific term "multiverse," which was coined in 1895 by psychologist William James, was popularized by science fiction author Michael Moorcock. In these contexts, parallel universes are also called "alternative universes," "quantum universes," "parallel worlds," "alternate realities," "alternative timelines," etc.

They say most of the other universes has laws that would not allow life as we know it to exist.  So it would be less of you being a few atoms different.  But the election being heavier or gravity not being as strong.  Universes where suns don't form.  Universes of pure electricity, etc.

Hugh Everett's many-worlds interpretation (MWI) is one of several mainstream interpretations of quantum mechanics. Other interpretations include the Copenhagen and the consistent histories interpretations. The multiverse proposed by MWI has a shared time parameter. In most formulations, all the constituent universes are structurally identical to each other and though they have the same physical laws and values for the fundamental constants, they may exist in different states. The constituent universes are furthermore non-communicating, in the sense that no information can pass between them, although in Everett's formulation they may potentially affect each other through quantum interference. The state of the entire multiverse is related to the states of the constituent universes by quantum superposition, and is described by a single universal wavefunction. Related are Richard Feynman's multiple histories interpretation and H. Dieter Zeh's many-minds interpretation.

Many worlds interpretation cannot explain the apparently Fine-tuned universe since the physical constants of all the "many worlds" are the same. The many worlds interpretation can, however, explain the apparent improbability of a planet like Earth existing. See Rare Earth hypothesis. If the many worlds interpretation is true there are so many possibilities that are realised, that the existence of at least one planet like Earth is not surprising.