Everyone loves the idea of parallel universes. Maybe it’s the appeal of an ideal world where you have second chances and things turn out differently. In alternate reality, where you do get into Hogwarts and the Star Wars prequels aren’t made and you finally connect your asymmetric computer cord correctly in the first try.
But is there really a place in science for such wistful speculation? Physicists use the word Universe when what they actually mean is Observable Universe i.e. the part of the whole universe that we have so far been able to see.
An alien near the edge of our observable universe will see parts of the whole universe that we can’t yet see, because the light hasn’t had time to reach us yet.
Now let’s cut to the chase.
In physics, the word Multiverse refers to one of three distinct and largely unrelated proposed physical models.
#1 Bubble Universes (Black Holes and Baby Universes)
The basic idea is that perhaps there are other parts of the world that are so far away or inside black holes that we will never see them.
#2 Membranes and Extra Dimensions
The string theorists proposed that, perhaps what we think of, is our universe, is actually just a three dimensional surface embedded with a larger super-universe with 9 spacial dimensions and there are other 3 dimensional surfaces just like our universe. You can say, our universe is one of potentially numerous ‘slabs’ floating in a higher-dimensional space, much like a slice of bread within a grander cosmic loaf.
#3 Many Worlds Theory of Quantum Mechanics
This theory proposes that every possible alternate timeline for the universe is real and they all happen in a ever larger, ever branching way. Like a universe where you choose your own adventure, every possible story happens. If this were the case, we will not realize it, because we will be stuck living just one infinitely many possible lives available to us.
To conclude, I’d say there is no experimental evidence to prove either of these models. Yet it is exciting to know the different possibilities that could be there in the world. Of course, we may end up being able to break out of the room, to look through a different window. But as it stands now, that’s pure speculation. Anything is possible in the extra-dimensional outer space.
