Brian Greene

One of the strangest features of string theory is that it requires more than the three spatial dimensions that we see directly in the world around us. That sounds like science fiction, but it is an indisputable outcome of the mathematics of string theory.

The central idea of string theory is quite straightforward. If you examine any piece of matter ever more finely, at first you'll find molecules, atoms, sub-atomic particles. Probe the smaller particles, you'll find something else, a tiny vibrating filament of energy, a little tiny vibrating string.

The science can tell you that the thousands of pseudo-scientific parenting books out there - not to mention the 'Baby Einstein' DVDs and the flash cards and the brain-boosting toys - won't do a thing to make your baby smarter. That's largely because babies are already as smart as they can be; smarter than we are in some ways.