  The traditional interpretation of radiative emission and absorption asserts
that photons are created and annihilated in such processes. A Gedanken
experiment is considered in which kinetic energy from observed photons is
systematically removed until a limit of zero is reached. With the help of the
relativistic Doppler effect it is shown that even for infinitesimally small
kinetic energies the photons continue to exist, since in other inertial systems
they will be observed to have a much higher energy/frequency falling in an
easily detectable range. It is possible to formulate an alternative explanation
for absorption and emission processes on this basis in terms of real photons
with exactly zero kinetic energy being present before or after radiative
interactions. Bolstering this hypothesis is the fact that the statistical
mechanical treatment of photons interacting with oscillators in blackbody
radiation theory predicts an infinite density of photons of this energy, both
in the original Planck formulation employing Maxwell-Boltzmann statistics and
in the subsequent Bose-Einstein description. These considerations demonstrate
that the E = 0 state is greatly preferred as the product of absorption because
of the requirement to have the interaction occur in a relatively narrow region
of space- time. There is thus strong evidence that photons are not created and
annihilated in radiative processes but simply have their kinetic energy changed
either to or from a zero value. Accordingly a very high density of zero-energy
photons is expected to exist uniformly throughout the universe. Finally, this
development suggests that one should subject the creation-annihilation
hypothesis to careful scrutiny in other areas of physics as well.
