WHY do we live in a space with only three dimensions? Because, at some time in the past, all the universes with four or more dimensions collided and destroyed each other, while our 3D space survived by slipping between collisions. Or at least, that is what a new theory claims.
It sounds like a tall tale. Can’t we accept that our universe has three space dimensions and that’s that? Not if you believe in string theory – physicists’ best bet for a fundamental description of all particles and forces – which needs nine spatial dimensions.
In one interpretation of string theory, called…
