I think a colony in space will take much longer than sci fiction writers think. It costs $10,000 to put a pound of anything into near earth orbit. That is your weight in gold. It costs about $100,000 a pound to put you on the moon. And it costs $1,000,000 a pound to put you on Mars.

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.

If all our common-sense notions about the universe were correct, then science would have solved the secrets of the universe thousands of years ago. The purpose of science is to peel back the layer of the appearance of the objects to reveal their underlying nature. In fact, if appearance and essence were the same thing, there would be no need for science.

In the future, I can imagine that we will genetically modify ourselves using the genes that have doubled our life span since we were chimpanzees.

Modern thinking is that time did not start with the big bang, and that there was a multiverse even before the big bang. In the inflation theory, and in string theory, there were universes before our big bang, and that big bangs are happening all the time. Universes are formed when bubbles collide or fission into smaller bubles.

There are many examples of old, incorrect theories that stubbornly persisted, sustained only by the prestige of foolish but well-connected scientists... Many of these theories have been killed off only when some decisive experiment exposed their incorrectness... Thus the yeoman work in any science, and especially physics, is done by the experimentalist, who must keep the theoreticians honest.

A force field is basically an invisible shield. You push a button and all of a sudden a bubble forms around you which is impenetrable. It can stop bullets, it can stop ray gun blasts and we realized force fields are actually a little bit difficult to create.