Einstein's theory of relativity does a fantastic job for explaining big things. Quantum mechanics is fantastic for the other end of the spectrum - for small things.

Sometimes nature guards her secrets with the unbreakable grip of physical law. Sometimes the true nature of reality beckons from just beyond the horizon.

String theory envisions a multiverse in which our universe is one slice of bread in a big cosmic loaf. The other slices would be displaced from ours in some extra dimension of space.

The main challenge that television presents is that I have a tendency to say things with a great deal of precision and accuracy. Often a description of that sort, which will work in a book because people can read it slowly - they can turn the pages back and so on - doesn't really work on TV because it interrupts the flow of the moving image.

If the theory turns out to be right, that will be tremendously thick and tasty icing on the cake.

I can't stand clutter. I can't stand piles of stuff. And whenever I see it, I basically just throw the stuff away.

The boldness of asking deep questions may require unforeseen flexibility if we are to accept the answers.