The 'photon sphere' is a location where gravity is so strong | Physics
The "photon sphere" is a location where gravity is so strong that light can travel in circles. Photons orbit the black hole at the distance of the photon sphere. A photon could leave the back of your head, go once around the black hole, and be seen by your eye. Yes! You can see the back of your head. ━━━━━━━━━━━━━ @Physics
