Extra dimensions in m-theory

M-Theory, also previously known as string theory (or a subset of string theory) suggests that in order to understand the forces in the universe it is neccessary to have around 11 dimensions.

But what are these extra dimensions? xyz and time can be dimensions but what about the others? Well the most common way these are described as smaller dimensions that are curled up on themselves.

mainfold

an example of a 3D Calabi-Yau manifold. image: wikipedia


"extra dimensions are wrapped up on six circles". These are more mathematical objects refered to as Calabi-Yau Manifolds and Orbifolds.

It is also though that some aspect of this manifold, folded extra dimensions may be larger and intersect with membranes.

The wikipedia suggests: " Calabi-Yau manifolds are shapes that satisfy the requirement of space for the six "unseen" spatial dimensions of string theory, which may be smaller than our currently observable lengths as they have not yet been detected.

"A popular alternative known as large extra dimensions, which often occurs in braneworld models, is that the Calabi-Yau is large but we are confined to a small subset on which it intersects a D-brane."

Sources/references: