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.

My daughter Gabby very kindly once said that she thinks I was a better mother because I was doing a job I loved. I now think guilt is a universal part of being a mother. I used to think it was Jewish-mother guilt but now I think it is working-mother guilt.