eli5 What the hell is 4-dimensional space?? I’ve seen lots of stuff about it lately and even the tesseract animations just make me more confused.

If we start from a point (0d), 1d is many points beside each other, so it's a line, then 2d is many lines beside each other- a plane, and 3d is many planes besides each other, so now we have space/volume. Now it gets tricky, since this is the limit of what we can visualize on account of us living in 3d space and not having other frame of reference., so a set volume/ space repeating itself many times is something we cannot visualize, but we do experience it, with a passing of time. The 4rth dimension is time. Take any space for example. It exist now, and also 10 seconds ago, and at any time bitween now and then, in a same manner how many points make a line, but at any point of the the line, there is a point. It is somewhat analogous with any 3d space - relative to 4th dimension, it as a point in line, where line is time. So when we think of 4-dimentional space, we can assign the regular 3d coordinate, like, X, Y, and Z, and 4rth coordinate is basically "when".

/r/explainlikeimfive Thread