  The study of the gravitational redshift\,---\,a relative wavelength increase
of $\approx 2 \times 10^{-6}$ was predicted for solar radiation by Einstein in
1908\,---\,is still an important subject in modern physics. In a dispute
whether or not atom interferometry experiments can be employed for
gravitational redshift measurements, two research teams have recently disagreed
on the physical cause of the shift. Regardless of any discussion on the
interferometer aspect\,---\,we find that both groups of authors miss the
important point that the ratio of gravitational to the electrostatic forces is
generally very small. For instance, the gravitational force acting on an
electron in a hydrogen atom situated in the Sun's photosphere to the
electrostatic force between the proton and the electron is approximately $3
\times 10^{-21}$. A comparison of this ratio with the predicted and observed
solar redshift indicates a discrepancy of many orders of magnitude. Here we
show, with Einstein's early assumption of the frequency of spectral lines
depending only on the generating ion itself as starting point, that a solution
can be formulated based on a two-step process in analogy with Fermi's treatment
of the Doppler effect. It provides a sequence of physical processes in line
with the conservation of energy and momentum resulting in the observed shift
and does not employ a geometric description. The gravitational field affects
the release of the photon and not the atomic transition. The control parameter
is the speed of light. The atomic emission is then contrasted with the
gravitational redshift of matter-antimatter annihilation events.
