In Einstein’s relativity and the Standard Model, we only have three spatial dimensions. But there could be more, and many think there are. — From any point in space, you are free to move in any direction you choose. No matter how you orient yourself, you can travel forwards-or-backwards, up-and-down, or side-to-side: you have three independent dimensions that you can navigate. There is a fourth dimension: time; we move through that just as inevitably…