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.

I was part of the draft resistance movement in L.A. where we did demonstrations at the draft centre and burned our cards and made a lot of trouble on campus. I had a student classification and they said that anybody who'd taken part in these demonstrations would be reclassified and drafted. And that's when I went to Canada.