The river of time may fork into rivers, in which case you have a parallel reality and so then you can become a time traveler and not have to worry about causing a time paradox.

We are slowly isolating the genes involved with the aging process. We do not have the fountain of youth, but I think, in the coming decades, we will unravel the aging process at the genetic level.

The Europeans and the Americans are not throwing $10 billion down this gigantic tube for nothing. We're exploring the very forefront of physics and cosmology with the Large Hadron Collider because we want to have a window on creation, we want to recreate a tiny piece of Genesis to unlock some of the greatest secrets of the universe.

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.

Sooner or later, we will face a catastrophic threat from space. Of all the possible threats, only a gigantic asteroid hit can destroy the entire planet. If we prepare now, we better our odds of survival. The dinosaurs never knew what hit them.

I don't. We've had three technological revolutions that have changed the course of human history, all driven by physics. In the first, the industrial revolution, physicists developed Newtonian mechanics and thermodynamics, which gave us the steam engine and machine power. The second technological revolution was the electricity revolution. That gave us radio, television, and telecommunications. Then, physicists developed the laser and the transistor.

We physicists don't like to admit it, but some of us are closet science fiction fans. We hate to admit it because it sounds undignified. But when we were children, that's when we got interested in science, for a lot of us.