The fourth dimension.
Even if you barely touch math, you've probably heard the phrase before. Maybe you've heard it's space? Or time? Perhaps you've heard a radio show about how apparently some phycisist theorizes the world is actually secretly an 18.5-dimensional spiderweb. Fourth dimensions pop up all the time in science fiction, sometimes under the guise of "alternate dimensions", or even "parallel dimensions". But what does it mean? How do you work with it?
Here's a little secret: mathematicians don’t actually care about WHAT the fourth dimension is. Figuring out whether our world has a fourth dimension, and whether it's time or space or speed or how fun it is to play around with math, is a PHYSICIST’s job. Once you have a fourth dimension, mathematicians care about figuring out how to describe it - ideally using numbers.
So in this explorable explanation, I'll show you one way that mathematicians think about four dimensions. Along the way, we'll deconstruct some coordinate systems, encounter the idea of a "manifold", and play with visualizing some 4D shapes - and, of course, it'll all be interactive.
Enjoy!