Do multiverses and parallel universes exist?

Do multiverses and parallel universes exist?

Imagining multiple universes or human beings living similar situations in other dimensions is truly fascinating. Parallel universes and multiverses are very popular nowadays, many films like "Interstellar" take this theory as a fundamental part of their fiction. However, it was William James and Hugh Everett who initiated and disseminated these theories. 

Multiverses and parallel universes are essentially theories based on the existence of multiples universes, with the difference that some are independent and others similar; that is, multiverses coexist with each other in a vast space, usually represented spherically, or by universes separated in dimensions. At present, the scientific community relies on Einstein’s law of relativity and quantum physics theory to prove its existence. Four hypotheses have been proposed trying to explain the multiverses and parallel universes, represented by types or levels:

1° This is explained by the theory of cosmic inflation which says that space is infinitely vast and therefore has an infinity of regions; so, there may be very similar or parallel regions to ours, but with infinite possibilities and that being such an immense space, these regions would be extremely far away that we could not see or reach them.

2° This indicates that there could be a "hyperspace" in which there are multiverses with a shape very similar to bubbles floating in the vastness. This infinity of universes can divide, collide with each other, and deform.

3° Parallel universes can share the same space and time; however, they would be separated by different dimensions, so they could not be observed, unless there was a wormhole. The similarity and variability between these universes are due to string theory, which states that particles are composed of filaments and membranes, which through their vibration, are spreading and transforming among the eleven possibly existing dimensions.

4° It is proposed that the laws of physics that govern each of the universes in the existing multiverses in a hyperspace are different, so that coming to have interaction between them could be catastrophic and impossible to realize.

To conclude, the theory of multiverses or parallel universes, widely recognized and accepted by some people, raises various hypotheses to explain their existence; however, so far nothing is scientifically proven. Regardless, the idea of intelligent life somewhere is really interesting. Perhaps one day humanity will be able to decipher this mystery.