The concept of the Multiverse: 24 variants of the possible
Is our universe unique? Or are there other worlds, with different physical laws and realities beyond our imagination? The laws of physics as we know them emerged at very early stages, when inflation, the rapid expansion of space-time, began. If our notions are correct, and only quantum fluctuations existed at the very beginning, an alternative universe would have slightly different laws of nature than the ‘earthly’ ones we are accustomed to.
Theoretically, quantum fluctuations could have given birth to another universe. If this happened, ‘they’ evolve according to their laws, and we evolve according to our own, accessible to us in the physical dimension.
Each universe, even if it started roughly the same from the hypothetical Big Bang, received its own constants, and later its physical laws.
From atoms to galaxies, the concept of the multiverse is a very old idea, discussed even in the philosophy of ancient atomism. It asserts that the physical world is composed of fundamental indivisible components, atoms.
Ancient philosophers assumed: infinite parallel worlds arose as a result of the collision of atoms.
In the 3rd century BC, Chrysippus taught that the world eternally ends and is reborn at a certain time. Essentially, he formulated a conceptual model, later realized in Penrose’s theory of the cyclical Universe.
Thus, the concept of the multiplicity of universes has come a long way, influencing modern physics.
In 1952, an already elderly Erwin Schrödinger gave a lecture, emphasizing that what he was about to say might seem insane. He claimed that his equations seemed to describe several different histories. These are not alternatives to one reality, because everything happens simultaneously.
This kind of duality was called superposition: it turned out that it explains not only the behavior of particles but also quite large macro-objects. Even cosmic structures like galaxies and galactic clusters.
Quanta, cosmos, and alternative universes
Our brain is evolutionarily not adapted to the intuitive understanding of quantum mechanics and large-scale cosmic phenomena, but we still try to find rational answers.
In the multiverse, areas that are expanding can exist simultaneously, not knowing about the existence of other worlds. They ‘live’ independently of each other and will never meet. To notice an alternative universe, breaking through in the native universe, is even theoretically impossible.
But there, beyond the horizon, is its horizon. The question is only in which, and under what circumstances such horizons intersect. We do not know how to do this from our universe, so we consider them to be those that do not have causal connections.
Someday, perhaps we will be able to find a way to tunnel from one universe to another, although the laws of physics … we do not know what this means. And what reality will arise when some laws conflict with their natural analogs.