“Parallel universes exist.”

The Many-Worlds Interpretation (MWI) of quantum mechanics holds that there are many worlds which exist in parallel at the same space and time as our own. The existence of the other worlds makes it possible to remove randomness and action at a distance from quantum theory and thus from all physics. It has frequently been claimed that the MWI is in principle indistinguishable from the ideal collapse theory, but the collapse leads to effects that do not exist if the MWI is the correct theory. The MWI is wrong if there is a physical process of collapse of the wave function of the Universe to a single-world quantum state.

Unlike other interpretations of quantum mechanics, such as the Copenhagen Interpretation or the pilot-wave theory, the MWI does not offer specific predictions that can be experimentally verified. This led some physicists to dismiss the MWI as unscientific or metaphysical speculation rather than a legitimate scientific theory.

The answer for better or worse is no. There is no empirically grounded scientific reason to believe there is such a thing as a Multiverse of parallel realities. In fact, the only time the Multiverse appears in scientific theories is as a bug rather than a feature.

The multiverse is one way to understand the behavior of very, very small things, such as atoms and subatomic particles. Scientists call the rules governing how these very small objects behave quantum mechanics. While it's a fascinating way to imagine quantum mechanics, it's just one interpretation, not undeniable evidence of the multiverse.

Not only can we not disprove any multiverse theory, we can't prove them either. We currently have no evidence that multiverses exist, and everything we can see suggests there is just one universe — our own.

It's clear that speculation about an infinite number of unobservable parallel universes is intrinsically untestable. Furthermore, even the theories that give rise to the multiverse—string theory and eternal inflation—have never been experimentally verified. The multiverse's failure to satisfy the key requirements of the scientific method (experimentation and testing) has moved some multiverse scientists to argue that we need to change the definition of science to accommodate it under the banner of science.

The multiverse is the idea that there's something beyond the immediately observable universe, and quantum mechanics and string theory together predict that our universe is contained in some very diverse, ever-growing multiverse. This is actually potentially observable if we're lucky because our bubble has and will collide with other bubbles, and those collisions have effects that we could measure, making the theory falsifiable.

According to the Many-Worlds theory, we can't truly be certain, since we cannot be aware of them. The string theory has already been tested at least once — with negative results. While physicists have managed to create machines that can detect quantum matter, the sub-quantum strings have yet to be observed, which makes them — and the theory on which they're built — entirely theoretical.

Durham Professor Tom Shanks proposed that the Cold Spot was 'caused by a collision between our universe and another bubble universe…The Cold Spot might be taken as the first evidence for the multiverse – and billions of other universes may exist like our own.' However, a more thorough analysis of data from the WMAP and from the Planck satellite did not reveal any statistically significant evidence of such a bubble universe collision.

In physics, the multiverse hypothesis arises in contexts like eternal inflation, string theory landscapes, and the many-worlds interpretation of quantum mechanics, but lacks direct empirical evidence or falsifiable predictions, leading most physicists to view it as speculative rather than established science.

In the many worlds theory of quantum physics, all possible outcomes of a quantum event occur, creating branching parallel worlds in which a different outcome is reality. According to a recently published paper, communication between those worlds should be possible under our current understanding of quantum physics.

Right now the Universe might be splitting into countless parallel Universes, each one with a new version of you. This weird quirk of quantum mechanics... This radical new approach is known as the many worlds interpretation of quantum mechanics... Still second to Copenhagen, but rising in popularity as time goes on.

Top physicists Emily Adlam and Jacob Barandes deliver a powerful takedown of the Many Worlds Interpretation. They expose why it’s more philosophical fantasy than scientific theory, revealing its lack of testability, predictive power, and real-world grounding.

According to some theories of quantum physics, there are infinite parallel universes that we can’t see or interact with. But what if, from time to time, that’s not true? The idea of parallel universes has saturated pop culture, and there’s no shortage of internet lore surrounding the concept.