  The Wheeler equation, for electromagnetic disturbances in a gravitational
field, was found by Fiziev to have exact solutions both above and below the
event horizon, in the form of waves propagating both inwardly and outwardly.
This observation can be interpreted and verified from the optical point of
view, entirely on the basis of the Schwarzschild metric for length contraction
and time dilation, in order to derive a differential version of Snell's law for
the Schwarzschild black hole. It reveals interesting physics, including the
correct amount of light deflection by the Sun, internal and external
Oppenheimer-Snyder cones of the black hole, properties of its phonon sphere and
the conclusion that light-rays are kept below the horizon by length contraction
and time dilation rather than deflection.
