  The momentum of light inside ponderable media has an electromagnetic part and
a mechanical part. The local and instantaneous density of the electromagnetic
part of the momentum is given by the Poynting vector divided by the square of
the speed of light in vacuum, irrespective of the nature of the electromagnetic
fields or the local or global properties of the material media. The mechanical
part of the momentum is associated with the action of the electromagnetic field
on the atomic constituents of the media, as specified by the Lorentz law of
force. Proper interpretation and application of the Maxwell-Lorentz equations
within the material bodies as well as at their surfaces and interfaces is all
that is needed to obtain a complete picture of the momentum of light, including
detailed numerical values at each and every point in space and time. That the
Abraham-Minkowski controversy surrounding the momentum of light inside material
media has persisted for nearly a century is due perhaps to an insufficient
appreciation for the completeness and consistency of the macroscopic
Maxwell-Lorentz theory, inadequate treatment of the electromagnetic force and
torque at the material boundaries, and an undue emphasis on the necessity of
coupling the equations of electrodynamics to those of the theory of elasticity
for proper treatment of mechanical momentum. The present paper reports the
resolution of the Abraham-Minkowski controversy within the framework of the
classical theory of electrodynamics, without resort to such complicating and
ultimately unnecessary factors as pseudo-momentum, special surface forces,
alternative energy-momentum tensors, and hidden momenta, that have caused so
much confusion for such a long period of time.
