Whether you're a fan of the popular TV show Rick and Morty or just a connoisseur of modern physics theories, you may know a thing or two about the multiverse theory. This theory states that the universe we live in may not be the only one out there. It proposes the idea that there are, in fact, an infinite number of universes, known as the multiverse.
This concept may seem a little insane, but it gets even weirder when you actually start thinking about its implications. If the multiverse theory is correct, then there's a universe out there where everything is exactly like this universe, but you're reading this article in a clown costume drinking a cup of maple syrup. If there is anyone out there doing that right now, please comment below so we can prove the multiverse theory once and for all.
Jokes aside, the multiverse theory isn't just physics quackery, its a trail of thought that has infatuated scientists and philosophers alike. While some physicists argue the multiverse is not a legitimate topic of scientific inquiry, let's take a look at a few things others point to as proof that we might be living in a multiverse.
Consider space-time. Scientists really can't be sure what the actual shape of space-time is. The shape of the universe depends on its density. If its density is greater than the critical density, the universe will be closed and form a curved shape; if less, it will curve, a bit like a saddle. But if the actual density of the universe is equal to the critical density, as scientists think it is, then it will extend forever like a flat piece of paper.
If that were the case – which many scientists think is likely – then if you travel far enough you will eventually reach regions nearly identical to ours. After all, an infinite series of numbers has an infinite number of possibilities, but there are only a finite number of ways that particles in space can be arranged. That means that at some point, there's going to be repetition.
Hence somewhere, by pure chance, if you look far enough down the space-time timeline, there could be a near-parallel Earth where a nearly-identical version of you is reading this article in a clown suit drinking maple syrup.
Our observable universe goes only as far as light has traveled in our universe's existence. That equates to roughly 13.7 billion light-years. The space-time beyond that boundary would essentially be considered its own universe. Some argue that there has to be something beyond our universe. Apparently, it might be another universe.
Inflation of the Universe
The principle of inflation suggests that the universe expanded rapidly after the Big Bang, a bit like a giant balloon. When this happened on a massive scale, some pockets of space might have stopped inflating, according to top cosmologists. This would essentially be like bubbles forming in the universe. These other bubble universes would have then moved away from us, well beyond the limits of observation.
Some cosmologists suggest that our own universe exists as one of those bubbles. This could also mean that if there were multiple universes, each would have their own unique laws of physics.
In the theory of quantum mechanics, there might be other ways that multiple universes can arise. For example, physicist Richard Feynman's approach to quantum field theory introduced the possibility of reality as a "weighted sum of alternative histories". For example, this theory proposed that the overall behavior of two electrons as they approach each other, then deflect and scatter, must take into account every possible intermediate path—and that these should be weighted according to the likelihood of each path. Another way to think of this is by trying to find out how tired a person will be after a walk in the woods by assuming that they split themselves up and take every possible route. More weight would be assigned to the shortest (and therefore most likely) path, but all of the paths need to be taken into account.
A graduate student, Hugh Everett III, took this further by proposing a reinterpretation of quantum mechanics in which each time that particles interact, reality separates into a set of parallel streams, each representing a different possible outcome. So, researchers observing a quantum experiment would similarly split up into multiple selves. Each version of the researcher would be convinced that she was the real one and would be unaware of the existence of the others.
2 + 2 = Another Universe
Scientists also debate the role of math in alternate universes. Is math something that we use to describe our universe, or is it really the essence of our universe?
If math is just a system that we use to understand our universe, then maybe there are other mathematical structures that exist in different universes. Under this theory, maybe there's another universe where 2+2=5. However, if math IS a fundamental reality, then every single universe would be defined by it equally.
A mathematical structure can be defined completely independent of human experience or even understanding. Whether you understand a mathematical principle or not, it still is. This theory of the universality of math, which many scientists think is accurate, would suggest that there are likely to be universes out there that would exist regardless of human experience.
Now that your brain is officially sizzled after questioning the realities of clown you drinking maple syrup in a parallel universe, take a break from that life crisis and ponder, what is the color of the universe? Scientists have actually figured that out – and even assigned it a HEX value. Watch the video below for that answer.