The multiverse hypothesis or theory holds that a group of multiple universes (possibly infinite universes) comprise everything that exists: The entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. The renowned astrophysicist Neil deGrasse Tyson explains in detail the multiverse hypothesis.
However, prominent physicists are divided about whether any other universes exist outside of our own. Some even go as far as to say that the multiverse is not a legitimate topic of scientific inquiry. Because it can not be empirically falsified. But Neil deGrasse Tyson among other prominent cosmologists, thinks that given our understanding of quantum mechanics and the thoery of General relativity, the possibility of the existence of the multiverse is a legitimate scientific hypothesis.
Steven Weinberg said that if the multiverse existed, the hope of finding a rational explanation for the precise values of quark masses and other constants of the standard model that we observe in our Big Bang is doomed, for their values would be an accident of the particular part of the multiverse in which we live.
Some scientists analyzed the data from the Wilkinson Microwave Anisotropy Probe, an uncrewed spacecraft operating from 2001 to 2010 that measured temperature differences across the sky in the cosmic microwave background, the radiant heat remaining from the Big Bang, and claimed they found evidence suggesting that our universe collided with other parallel universes in the distant past.
However, a more thorough data analysis from the Wilkinson Microwave Anisotropy Probe and from the Planck Satellite, a space observatory operated by the European Space Agency from 2009 to 2013, which mapped the anisotropies of the cosmic microwave background, did not find any statistically significant evidence of universe collisions. there was no evidence of any gravitational pull of other universes on ours either. And to add insult to injury to the proponents that the multiverse hypothesis has been backed up by statistical evidence, the Planck satellite, has a resolution three times higher than the WMA Probe.
Our brains are not evolutionarily equipped to intuitively understand quantum mechanics and large scale cosmic phenomena. But Neil deGrasse Tyson with his usual wits explains the multiverse hypothesis in layman's terms.