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.

We can summarize electricity, magnetism and gravity into equations one inch long, and that's the power of field theory. And so I said to myself: I will create a field theory of strings. And when I did it one day, it was incredible, realizing that on a sheet of paper I can write down an equation which summarized almost all physical knowledge.

In my mind, there is no question that they're out there. My Career is well established. My texts books are required reading in all the major capitals on planet earth. If you want to become a physist to learn about the unified feild therory-you read my books. Therefore, I'm in a position to say: Yes- Most likely they're out their, perhaps even visited, perhaps on our moon.

I realized very early in life what my abilities and limitations were, and foreign languages was definitely one of my limitations. With strenuous effort, I just barely passed my French class at Harvard so I could graduate.

It's risky to allow radiation to constantly go up into the atmosphere. The main criticism of this approach of entombing it is that it would cost too much, involve too many resources and people. But think of the cost of having all the crops impounded by the government, all the milk being thrown into the river, people's livelihoods destroyed.

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.

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.