The concept of the multiverse implies the existence of many parallel worlds with different physical properties. As noted by ScienceNews, this idea intrigues physicists not only because of its captivating narratives but also because it may help address fundamental questions about the structure of the Universe.
One of the theories is related to cosmology and the inflationary period that began shortly after the Big Bang. At that moment, the Universe was expanding at an enormous rate, and quantum fluctuations were stretching to cosmic scales. These oscillations became the foundation for the formation of galaxies in the observable part of the Universe. However, beyond the visible cosmos, which is inaccessible to us, such fluctuations could have led to the formation of regions of space with entirely different properties.
Physicist Andrei Linde from Stanford University argues that in such regions, different values of particle masses and distinctive behaviors of fundamental forces may exist. For example, electrons could be significantly heavier, and gravity could operate under different laws. In most of these worlds, life is likely impossible. Nevertheless, inflation may not end everywhere, implying that new "bubbles" of space continue to emerge in the Universe—separate universes with unique characteristics.
This hypothesis helps explain why the physical constants in our Universe appear to be finely tuned for the existence of life. If there are many worlds, the probability of at least one having suitable conditions becomes much more plausible. Theoretically, traces of collisions between such universes could be detected in the cosmic microwave background radiation, which is the afterglow of the Big Bang. However, as physicist Paul Halpern from Saint Joseph's University in Philadelphia notes, no such evidence has yet been found.
There is another version of the multiverse that arises from quantum mechanics. It suggests that particles can exist in multiple states simultaneously until measured. In 1957, physicist Hugh Everett III proposed an interpretation in which all possible outcomes of quantum events are realized, but in different realities. In this case, each alternative exists in its own universe, and observers have no way of knowing about their copies. This theory remains extremely challenging to experimentally verify.
Even if parallel worlds do exist, the path to them remains purely hypothetical. Physicists suggest that different realities could connect through wormholes—tunnels in spacetime. However, the question of whether such structures are possible in principle remains open. Paul Halpern emphasizes that even if such objects exist, creating them would require colossal energy and mass that are beyond current technology.
