The Kaluza-Klein mechanism

The Kaluza-Klein mechanism is an idea in physics that suggests our universe has extra spatial dimensions beyond the familiar three. These additional dimensions are curled up very tightly, so small we can't detect them directly. When physicists try to describe forces like gravity and electromagnetism in higher dimensions, these curled-up dimensions give rise to different forces and particles we observe. Essentially, the mechanism links the geometry of these tiny extra dimensions to the fundamental forces, providing a unified way to understand the forces in nature through the shape and size of extra dimensions.