Ever wondered just wtf?!? is up with all these multi-dimensional theories? This might help. One of the exciting things about the Large Hadron Collider is, if they can keep it from exploding at any rate, that it will be able to reach energies which should allow us to prove, or disprove, at least some of these "multi-D" theories.

Or create a black hole that'll swallow us all. I forget.