The extention on Multiverse
(sorry this is really late)
My first blogpost brings up these questions:
Do multiverses actually exist? Are we currently in a layer of a parallel universe or, even larger, a multiverse?
In this blogpost I will clarify and go more into depth about the different levels and types of multiverses.
Max Tegard, a MIT cosmologist, is one of the few who attempt to categorize the concepts of parallel universes into context and wrote a paper on it (if any of you want to read more into his explanation of his categorization).
Level 1: An infinite universe that, by the laws of probability, must contain another copy of Earth somewhere
This first level is the one where most people are able to accept. This level implies that since the universe is so massive and infinite, that somewhere out there, there are other planets that are just like Earth. Each Hubble volume(represents our observable universe) surrounding the planets would have the same physical laws and physical constants, however, the distribution of matter would vary.
If the different Hubble volumes do exist, it is not possible to contact them as we can only get messages from within our own Hubble volume.
Level 2: Other distant regions of space with different physical parameters, but the same basic laws
In this level, different areas of space are continuing to expand and inflate. Because of the continuous inflation in universes, the space between our universe and other universes are continuously expanding and therefore becomes virtually unreachable. Some regions of the space stop expanding and become separate bubbles, where each individual bubble is a level 1 universe.
This version predicts that different regions of space can exhibit different laws of physics.
Below is an example that hopefully makes this level a little more clear:
Consider flapping a sheet up and down rapidly onto the surface of a bed. The sheet doesn’t touch the bed only in one location, but rather touches it in multiple locations. If the sheet were a brane, then each point of collision would create its own universe with its own initial conditions. (x)
Level 3: Other universes where each possibility that can exist does exist, as described by the many worlds interpretation (MWI) of quantum physics
This level is particular to the different interpretations of the Many World Interpretation(MWI) by Hugh Everett where everything that could happen does.
Tegmark argues that a level III multiverse does not contain more possibilities in the Hubble volume than a level I-II multiverse.
The only difference between Level I and Level III is where your doppelgängers reside. In Level I they live elsewhere in good old three-dimensional space. In Level III they live on another quantum branch in infinite-dimensional Hilbert space.(Tegmark)
This viewpoint also implies that Level 1, 2, and 3 Multiverses are the same thing which is referred to as “Multiverse=Quantum Many Worlds.”
Level 4: Entirely distinct universes that may not even be connected to ours in any meaningful way and very likely have entirely different fundamental physical laws
The 4th level is Tegmark’s own belief where universes would follow different laws of nature comparatively to our own universe. Things may be similar in how humans may look but differ in surrounds. This level is one that most science fiction novelist turn to, where anything imaginable is quite possible.
Basically entailing that “any universe that physicists can get to work out on paper would exist”(xx)
Quite honestly, there is no way to prove with statistics and factual evidence that we are living in a multiverse. Furthermore, the conceptions of multiverse and theories that have arose are still, in fact, theories. So with this in mind, my questions posed in the beginning(Do multiverses actually exist? Are we currently in a layer of a parallel universe or, even larger, a multiverse?) cannot be answered. If I had any other questions to ask, it would be if it is possible to prove that these theories are true.