Effective and Inertial Masses of a Photon Near a Black Hole for a Family of Envelope Orbits

minimum radius

r

0

1.6

Photons move along geodesic paths, which are bent in a gravitational field. This allows one to assume that the photon has a finite inertial mass. This Demonstration shows how the effective and inertial masses change as functions of the distance

r

to the center of gravity and the motion constant

h

for the photon's orbits near a black hole with minimum radius

r=

r

0

. The unit of distance is chosen as the Schwarzschild radius, such that

r

s

=1

.