“What really interests me is whether God had any choice in creating the world.” Albert Einstein on the possibility of other Universes. The Perplexing Mystery Of The Multiverse fascinated Albert Einstein, and it continues to fascinate scientists today!
One of the most famous people to question whether our universe is truly the only possible universe was Albert Einstein. Of course, when Einstein referred to “God,” he did not do so in a theological sense—instead, he was questioning whether the laws of physics necessarily yield a single universe (ours), or if they could allow for universes with a wide range of different features. And if there were other universes out there, he wondered, is our universe today just the product of a random process—a roll of the dice? Or is there a deeper explanation?
From Einstein’s day to now, this question has shifted from the outskirts of physics to the mainstream. And there are many theories that suggest that there are other universes, separate from ours, made from different kinds of particles and governed by different forces. This idea of a ‘multiverse’ is one of the most polarizing concepts among physicists today, sparking heated debates between those who believe it is the next step to understanding our existence and those that think it is a nonsensical distraction.
Below are the five most plausible scientific theories that are on the table today:
This is the idea that because space-time stretches out infinitely, then it must start repeating at some point, because there are a finite number of ways particles can be arranged in space and time. This theory proposes that if you look far enough, we would encounter another version of ourselves—and because the observable universe extends only as far as light has had a chance to get since the Big Bang, the space-time beyond that distance could be its own separate universe.
The foundation of this arguments rests on eternal inflation—the idea that suggests that some pockets of space stop inflating while other regions continue to inflate, giving rise to many isolated “bubble universe.” According to this theory, inflation has ended in our own universe, allowing stars and galaxies to form. We are only one bubble in a vast sea of space—made up of bubble universes where the laws of physics may be different than our own.
This is one of the more wildly recognized theories—the idea that parallel universes hover just out of reach of our own. The idea stems from the possibility that there are many more dimensions to our world that the three of space and one time that we recognize today. In addition to our own “brane” of space,” there could be other three-dimensional branes floating in a higher-dimensional space.
The theory of quantum mechanics describes the world in terms of probabilities instead of definite outcomes. The mathematics of this theory could suggest that all possible outcomes of a situation do occur—in their own separate universes. According to this theory, in each universe, there’s a copy of you witnessing one or the other outcome, with the incorrect assumption that your reality is the only one that exists.
Math is a tricky subject among scientists, who have long debated whether mathematics is simply a useful tool for describing the universe or whether it is the fundamental reality—and our observations are just perfect examples of this reality. If the latter is true, it goes to follow that the particular mathematical structure that makes up our universe isn’t the only option.