06/30/2022
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.
However, in some alternate universe, you may well be reading this article in a clown costume while drinking a cup of maple syrup. Or, any other combination of differences you can imagine.
Jokes aside, the multiverse theory isn't just physics quackery, it's 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 some physicists point to as proof that we might be living in a multiverse.
Somewhere out there is another exact copy of you, maybe.
Consider space-time. Scientists really can't be sure what the actual shape of space-time is. This is because the shape of the universe depends on its density.
If its density is greater than the critical density (the average density of matter required for the Universe to just halt its expansion), the universe will be closed and form a curved shape; if less, it will form a shape 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 while drinking maple syrup.
Our observable universe goes only as far as light has traveled in our universe's existence. That equates to a diameter of roughly 93 billion light-years. If we assume our current laws of physics are correct, we can set limits on the minimum size the Universe must be before it curves back on itself.
Observations tell us that if the Universe does curve back on itself and close, that the unobservable part of the Universe must be at least 250 times the radius of the observable part — at least 23 trillion light years in diameter, and with a volume more than 15 million times as large as the volume we can observe.
However, it's also possible that the entire Universe is just barely larger than the part we can observe, and that there is an "edge". If so, the space-time beyond that boundary would essentially be considered its own universe. Some argue that there has to be something beyond our universe. It might be another universe.
What are your opinions on this?
