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

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

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 to the center of gravity and the motion constant for the photon's orbits near a black hole with minimum radius . The unit of distance is chosen as the Schwarzschild radius, such that =1.

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