Once confined to fantasy and science fiction, time travel is now simply an engineering problem.

Futurism today is led by science-fiction writers, by sociologists, by historians. Now, I have nothing against them. I'm sure they do great work. But they're not scientists. They're clueless.

When you come up with a theory, you fall in love with the beauty the simplicity and elegance of it. But then you have to get a sheet of paper and pencil and crack out all the details. Hundreds and hundreds of pages. Because you have to prove it.

To understand the difficulty of predicting the next 100 years, we have to appreciate the difficulty that the people of 1900 had in predicting the world of 2000.

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

Some people seek meaning in life through personal gain, through personal relationship, or through personal experiences. However, it seems to me that being blessed with the intellect to divine the ultimate secrets of nature gives meaning enough to life.

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.