Multiverse theory, reality, or simply an idea?

   Multiverse theory, reality, or simply an idea? 

Are parallel multiverses real or not? The answer is that we don't know. We have no observations about those things. And that means they are non-proven models or theories. Or, maybe we should call the multiverse: "logical continuum of the universe structures, or models". 

So, it's rather philosophy than a scientific theory. That model explains dark energy, dark matter, and other unknown things as the energy and particles that come from another universe. There are instances where the universe in which we live will fall back to a single point. And then form again. That model is called "phoenix universe". Or in some models, another universe exists in the fourth or higher dimensions. But those models are unproven.. And maybe they will be unproven forever. In some models, things like virtual reality are also part of the multiverse or parallel universe theories. 

Multiverse is the theoretical framework where the universe is introduced as one of many universes. Or is it even a theoretical framework? The fact is that there is no single evidence of that thing. So, the multiverse theory is rather a philosophical conjecture or, so-called, logical expansion of the observations that researchers made of the universe. That means that if we believe the universe is composed of galactic superclusters, other universes would be universe-scale superclusters or hyperclusters. 

The other universe would be so dim that we cannot see it. In that type of observation, stars and other structures in our universe deny that sensors can detect radiation that comes from other universes. If they even exist. And who cares if those other universes exist? The multiverse is one of the models that tries to explain where matter came to our universe. That model could explain where matter came to our universe. But it would not explain where material in other universes came from? 

But there is one very interesting model of the multiverse. That model tells us that maybe we live in a black hole. Those hypothetical models explain why we cannot see things outside the universe that the black hole's material disk and halo press all waves that come from outside into a straight form. That means that we cannot see information in that wave movement. That model means that there can be other universes in the black holes. 

Those things are the fourth dimension. So there is a theoretical model. The black holes involve structures that are like our universe. So, that is one of the models that are made to explain why the universe exists. And the universe is part of the system of internal black holes. That is one of the models of the multiverse theory. 

But does the time reverse destroy that model? If we think of internal black holes, there is a possibility that when information comes to the edge of the next black hole or black hole's event horizon, time starts to move oppositely. So that means every black hole causes time reversal. But does that thing cause retrocausality? The retrocausality means that reaction comes before action. 

Even if those particles turn younger. Don't mean that things start to happen backward. 

Retrocausality seems like somebody looks at the film backwards. Or, that's how we represent that thing. But the fact is that retrocausality is not seen in large-scale structures. That thing is seen only in the smallest subatomic particles and their superposition tests. 

But then we can imagine one of the most interesting things in the multiverse philosophy, or the multiverse hypothesis. That thing is the anti-universe. Time moves backward because the anti-universe is in the middle of the big crunch.  Because particles and quantum fields turn closer and fields turn denser, that means time moves backward in that hypothetical space. But that doesn't necessarily mean that there is retrocausality in that universe. Maybe all things happen the same way as on Earth. But particles turn younger. 

A hypothetical black hole in that hypothetical universe will be an interesting thing. The idea is that time turns to travel backward in the point of the event horizon. So, that means that if the black hole is in an anti-universe, time travels oppositely in that black hole. So if time travels backward in the space behind the event horizon. That means time travels like it does in our universe if time travels backward around the black hole. 

The anti-universe means the universe that falls to the Big Crunch. Because all fields turn denser and stronger, the black hole will expand all the time. That means there is a possibility that this theoretical black hole in the theoretical anti-universe will not send gravity waves, because an expanding event horizon will close gravity waves inside it. The anti-universe doesn't necessarily mean a universe that forms from antimatter. Antimatter is like regular matter otherwise. 

But antimatter electrons have positive and antimatter protons have negative electric polarity. The anti-neutron spin is opposite to that of the neutron.  When an antimatter particle touches its mirror particle, both of those particles turn into radiation in the violent reaction called annihilation. That is the most powerful reaction in the known universe. But otherwise, antimatter reacts the same way to gravity and other fields. Antimatter is planned to be used in spacecraft. Because. It gives a very strong energy load. But that's the own story. 

https://bigthink.com/starts-with-a-bang/parallel-universes-multiverse-real/

https://www.space.com/space-exploration/james-webb-space-telescope/is-our-universe-trapped-inside-a-black-hole-this-james-webb-space-telescope-discovery-might-blow-your-mind

https://www.space.com/32728-parallel-universes.html

https://www.sciencenewstoday.org/the-multiverse-are-we-living-in-one-of-many

https://en.wikipedia.org/wiki/Multiverse

https://en.wikipedia.org/wiki/Retrocausality