This might be a little too complex but after Melvin Bragg this morning I started thinking.
Black holes are centres of mass with gravity so powerful that light cannot escape.
The speed of light is constant, and I understand (well know of, fully understand might be a bit far) that sometimes there is time distortion to keep it constant a la the Einstein train clock experiment.
However, how does this work with a black hole? Light photons are trying to move away but cannot? So they zoom out at the speed of light until they cannot and then go the speed of light in the other direction? They speed of light circle the black hole? Time doesn’t exist in a black hole?
In essence the question is how does one square the fact that the speed of light is a constant but it cannot escape a black hole?