watch Latest Paper Explains Video why the Universe ended up with 3 Dimensions

It's probably not reports to you that as residents of this fine Universe we call home, we can just move left or right, up or down, backwards or forward. That’s it. There aren’t any other possible directions that aren’t some mixture of those three.
These are our Universe’s three spatial dimensions, and why we have precisely three of them (not presently one or two, five or 80) is still something of a mystery.
Not those physicists haven’t been searching for an answer - explaining the original nature of reality is just a really hard nut to crack. But a latest paper has shown that a universe with our laws of thermodynamics (which describe how energy moves around) will forever get stuck with just three spatial dimensions. So essentially, this paper just explained the Universe.

explained it with the opening and second laws of thermodynamics.
For our purposes, these laws say that a system - whether it’s a universe, a person, or a rock - can’t do anything that requires additional energy than it has to start out, unless it gets additional energy added. And if the system gets larger without gaining energy, like we think our Universe has, then, on average, there’s less energy obtainable in any particular place.

Put those jointly, and it means that once the Universe stopped having enough energy to complete the same action everywhere, the whole Universe could never do that thing again - though convinced parts of it might be able to if they could think enough energy.
We’ll get back to that shortly, but the above account probably irks some of my fellow physicists. Get a deep breath. It’ll be okay.
Thermodynamics works in any figure of dimensions. It works in our 3D Universe, of course, but it also would work in two spatial dimensions, where the only likely directions to travel were left-right and up-down. In a two-dimensional universe, it would be bodily impossible to move backward or forward, because that way presently wouldn’t exist.
Oh and by the way, the researchers as well propose that it’s likely, in theory, to pack enough energy into a tiny bit of space that - in that one spot - the Universe momentarily escape its rut. It might take a particle accelerator the size of the Solar System, but in principle, it's doable.
If we ever do get amazing like that running, maybe we’ll see a proton, for the most fleeting of moment, move flirp for a not many trillionths of a metre before the boring old-left.