> What other space apart from 3 dimensional space exists? And what does that even mean? Aside from the one and two-dimensional spaces mentioned in a sibling co

> What other space apart from 3 dimensional space exists? And what does that even mean? Aside from the one and two-dimensional spaces mentioned in a sibling comment (ℝ¹ and ℝ²), there's also spaces with more interesting geometry. For example, S² is the two-sphere, more conventionally known as "the surface of a ball." On the sphere, the equivalent of straight lines are the great circles. S¹ would be the one-sphere (the circumference of a circle), and S³ would be an interesting, periodic three-dimensional space – kind of like what our universe would be if it were closed rather than (probably) open.