Growing new organs of the body as they wear out, extending the human lifespan? What's not to like? Then in the last phase of this transition people begin to realize, hey, I thought of it already - this is something that everyone can enjoy.

No matter how beautiful the theory, one irritating fact can dismiss the entire formulism, so it has to be proven.

The reactors in Japan are stable in the same way that a ticking time bomb is also stable. It wouldn't take much to light the fuse - a 6.6 earthquake, like what happened today in Japan, a pipe break, an over-pressurized containment vessel - anything could set it off, in which case we would have another Chernobyl, three times the magnitude of a Chernobyl accident.

For relaxation, I like to figure skate. Being on the ice and spinning and jumping, I feel very close to nature. In particular, I feel very close to Newton's laws of motion. On the ice, you can experience Newton's laws of motion in their purest, most elegant form.

We've done a miserable job of preparing people for today's world, let alone tomorrow's.

So often, science fiction helps to get young people interested in science. That's why I don't mind talking about science fiction. It has a real role to play: to seize the imagination.

String theory is based on the simple idea that all the four forces of the universe: gravity, the electromagnetic force and the two nuclear forces, can be viewed, as music.