Chapter 7, Brane New World Summary and Analysis

Today, the Theory of Everything, or M-Theory, has no single formulation as far as we know. What we have appears to be only an approximation of what there is. The true story may be utterly different than we think, just as Einstein was utterly different from Newton. Our current scientific theories continue to penetrate to small and smaller distances, and if this trend continues, science will discover new levels of particles, just as we discoverer quarks. But there is a limit to this series.

The smallest length in physics is the Planck length. Examining smaller distances requires more energy than exists in black holes. We are not sure what the Planck length is, given M-theory, but it may be as small as a millimeter divided by a hundred thousand billion billion billion. Yet mathematical models...