Four-Dimensional Spacetime, Why Not More?

We live in a four-dimensional universe, but could there be extra dimensions hiding? If so, why don't we see these extra dimensions?

It turns out that extra dimensions are very plausible and could help us unify our forces and explain how our universe became the way it is. However, it is not clear why these extra dimensions are hidden, leaving us with only four. There may be some anthropic reasons behind this: if extra dimensions aren't hidden away, it could reduce the explanatory power of our physics models. So, four dimensions may be a Goldilocks number that creates a hospitable universe.

In this episode, we explore what a higher-dimensional universe may look like and how it could help us understand why our universe is four-dimensional.