  We present a theory of light scattering consistent with modern physics. We
proposed a spatial-temporal model of a photon based on classical model of
atomic oscillator. Using this photon model, we established a criterion for
single vs multi-photon irradiation of matter. We demonstrated that the
assumption that induced dipole radiation can be of infinitely small power is
inconsistent with quantum mechanics. We proposed the energy criteria for
scattering of a photon on single and multiple atoms and free electrons. This
criterion revealed the limitations and applicability of Rayleigh's and
Thomson's models of scattering. According to our theory, light scattering is a
threshold process, and the scattering can only take place for those photons
with wavelengths shorter than some threshold. Using our model, we computed the
loss of energy by a photon with wavelengths longer than the scattering
threshold during interaction with bound and free electrons. We showed that a
single photon can lose energy in collisionless interaction with atoms,
molecules, and free electrons. The new theoretical model predicts the red shift
of photon wavelength resulting from such interactions. In particular, it
provides an explanation for the blue color of sky and an alternative
explanation for the cosmological red shift.
