Greene is a string theorist, so his answer—as yet unconfirmed by science—goes something like this: if we could examine these elementary particles with the utmost precision, we would find tiny vibrating loops, or strings. This theory stands in contrast to classical physics, which holds that matter is composed of indivisible, zero-dimensional point-particles with no size or internal structure.
String theorists like Greene believe that string theory may resolve the clash between quantum mechanics and general relativity that has tormented physicists for so many years. String theory would brilliantly resolve Einstein’s failed thirty-year quest to uncover a unified field theory of the universe.
The search for the underlying coherence of the universe has become something of a Holy Grail in physics today. String theory offers a framework for understanding everything in the universe, from the big bang to the tiniest constituent of an atom. In today’s scientific community, string theory is both thrilling and extremely controversial, especially because its predictions have yet to be proven experimentally. From this standpoint, string theory is still at a very early stage. Its mathematical underpinnings are still so complex that, as yet, only approximations of equations and their answers exist. The most recent studies suggest that string theory belongs within an even larger framework, which is named M-theory.