Why Parallel Universes Exist

The trope of the multiverse in science fiction is a fascinating way of combining all the characters and worlds in a series. Recently, “Spider-Man: No Way Home” expanded the Marvel Cinematic Universe into a multiverse, encompassing other franchises. While this implementation was a narrative device to do a crossover event, parallel universes are very probable in our real world, and there are sound theories backed by acclaimed scientists.

The first theory is based on probability. Each universe is categorized by a set of particles arranged in such a way that it will develop into that universe. The Earth only exists because its particles were in the correct time and place to form a ball of mass that orbits our sun. In order to find similar universes, we have to search for a universe with a similar set of particle configurations. Since the universe is unfathomably huge, the chances that similar particle configurations exist are extremely high. Each parallel universe then has minute differences that result in infinite possible results. Every possible variation of the universe we live in, as well as its replicas, is in the realm of possibility.

The next theory is based on the Big Bang, the idea that the universe started off as an infinitely dense point that suddenly stretched and inflated outwards at a rate faster than light. Some scientists have extended this theory to the hypothesis of “eternal inflation.” To simplify, the idea is that the universe constantly inflates through having most patches of the universe self-reproduce and inflate as bubbles. These mini-universes then self-produce and multiply indefinitely. This hypothesis supports the idea of parallel universes, as it says inflation is eternal. If the universe is infinite, then that idea not only means that other life exists, but also that life similar to our world’s organisms exists. To take it further, there’s the implication that similar worlds exist in our universe’s many bubbles, since each bubble has its own characteristics that are mostly replicated in each offspring bubble, therefore demonstrating the existence of parallel universes.

Another scientific theory for the multiverse is based on quantum mechanics. Quantum mechanics is a complex subject that people are still researching today, but what best explains parallel universes is the double-slit experiment, which demonstrates that light can have the same characteristics as both a wave and particle. If there is a light source that illuminates a plate with two slits, the wall on the other side of the plate will show a pattern that indicates that light travels as a wave. The interference pattern looks like drops of water rippling in a puddle. However, if one were to observe a single photon pass through a specific slit, the light would act as a particle. This phenomenon is the concept of wave-particle duality; paradoxically, light and even matter can behave as both a wave and particle. The takeaway from the double-slit experiment is the idea of superposition: quantum objects can be in two different states at the same time. The wave function encompasses all of reality and all possibilities, so it is in superposition. Our observations of and interactions with our universe cause the wave function to collapse, as only one outcome can occur.

Though all three of these theories are quite convincing, they’re just theories. Over time, new experiments and discoveries will bring us closer to the truth, proving or disproving the theories on parallel universes. Nowadays, with increasingly impressive technology and brilliant scientists to debate over the subject, the science fiction idea of parallel universes may become fact. However, it will take a long time to find out the truth, and interacting with another universe will take even longer. So until then, we can ponder the possibilities.