Seeing Further: The Story of Science and the Royal Society

by Bill Bryson

Since 1973, this focus upon symmetry has taken centre stage in the study of elementary-particle physics and the laws governing the fundamental interactions of Nature. Symmetry is the primary guide into the legislative structure of the elementary-particle world, and its laws are derived from the requirement that particular symmetries, often of a highly abstract character, are preserved when things change. Such theories are called ‘gauge theories’. All the currently successful theories of four known forces of Nature – the electromagnetic, weak, strong and gravitational forces – are gauge theories. These theories prescribe as well as describe: preserving the invariances upon which they are based requires the existence of the forces they govern. They are also able to dictate the character of the elementary particles of matter that they govern. In these respects, gauge theories differ from the classical laws of Newton, which, since they governed the motions of all bodies, could say nothing about the properties of those bodies.

Intersting concept