noun · rare

photon sphere

photon sphere · photon spheres

Photonensphäre

Of a black hole, a spherical limit around a black hole at such distance that any…Of a black hole, a spherical limit around a black hole at such distance that any photon meeting it tangentially is constrained to travel in a circular orbit; (more loosely) the region between this limit and the event horizon.

Meaning

1 senses

Of a black hole, a spherical limit around a black hole at such distance that any photon meeting it tangentially is constrained to travel in a circular orbit; (more loosely) the region between this limit and the event horizon.
The radius of the photon sphere is also the lower bound for any stable orbit.
For a Schwarzschild (non-spinning) black hole, the radius of the photon sphere is 1.5 times the Schwarzschild radius.
Photonensphäre