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.

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.

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.

Some advice: keep the flame of curiosity and wonderment alive, even when studying for boring exams. That is the well from which we scientists draw our nourishment and energy. And also, learn the math. Math is the language of nature, so we have to learn this language.

Impossible is relative.

It would take a civilization far more advanced than ours, unbelievably advanced, to begin to manipulate negative energy to create gateways to the past. But if you could obtain large quantities of negative energy-and that's a big "IF" - then you could create a time machine that apparently obeys Einstein's equation and perhaps the laws of quantum theory.

It's pointless to have a nice clean desk, because it means you're not doing anything.