Impossible is relative.

Cesium, iodine from the Chernobyl reactor accident went around the world many times and everyone on the Earth has a piece of Chernobyl in their bodies, but it's very tiny - too small to cause much damage.

I agree, along with Carl Sagan, that we should eventually become a two planet species. Life is too precious to place on a single planet.

We're in 'Jurassic Park' territory. If we go to the zoo in the future, we'll have zoos for extinct animals.

After that cancellation [of the Superconducting Super Collider in Texas, after $2 billion had been spent on it], we physicists learned that we have to sing for our supper. ... The Cold War is over. You can't simply say "Russia!" to Congress, and they whip out their checkbook and say, "How much?" We have to tell the people why this atom-smasher is going to benefit their lives.

To become a theoretical physicist ... you need to have a passionate love affair with the universe.

I'm not a science fiction writer, I'm a physicist. These are scientists who are making the future in their laboratories.