| The symbol is used in a number of different contexts in physics. In the SI system of units, the symbol denotes the multiplier , corresponding to the prefix "micro." In particle physics, denotes the muon particle. In celestial mechanics, where G is the gravitational constant and M is the mass of the central body. In radiative transfer, it denotes an angle defined as where is the angle of incidence. Magnetic Permeability © 1996-2007 Eric W. Weisstein |