In everyday life, we experience three spatial dimensions—length, width, and height—and one time dimension, making up our 4D universe. But theoretical physics, especially string theory, suggests the existence of more dimensions, possibly up to 10 or 11.

A fifth dimension could represent alternate timelines or realities, allowing for the idea of parallel universes. A sixth dimension might contain all possible worlds with the same starting conditions as our own but different outcomes, like a map of every possible variation of history.

These extra dimensions are not directly visible because they could be “compactified”—curled up at microscopic scales. Think of a tightrope: to a human, it looks one-dimensional, but an ant walking on it experiences a second dimension by moving around its circumference.

Though still theoretical, higher dimensions help scientists build unified models of physics and may one day explain mysteries like gravity, dark matter, or even consciousness itself.