Superstring theory

Scientifically speaking, a butterfly is at least as mysterious as a superstring. When something ceases to be mysterious it ceases to be of absorbing interest to scientists. Almost all things scientists think and dream about are mysterious.

— Superstring theory

Imagine, if you can, four things that have very different sizes. First, the entire universe. Second, the planet Earth. Third, the nucleus of an atom. Fourth, a superstring. The step in size from each of these things to the next is roughly the same... twenty powers of ten....

— Superstring theory