> From an outside observer they never cross the event horizon, due to the time dilation mentioned by the other comment.
Doesn't that imply that if we look at a black hole from a safe distance, the event horizon will appear to be a cluttered frozen motionless ring, full of all the stuff that is in the process of falling in but which from out point of view, never will?
Almost, another detail is the closer the object gets to the event horizon, the more it's light redshifts - until it's no longer in the visible spectrum at all. You can think of the black hole's gravity as stealing energy from the light, shifting it into a lower energy spectrum.
Sort of, the red shift continues towards infinity, but since photos are quantitized there is a last photon.
Also don't forget even if you freeze forever as viewed by an external observer, the blackhole is growing, and will at some point consume everything that had previously fallen in.
Doesn't that imply that if we look at a black hole from a safe distance, the event horizon will appear to be a cluttered frozen motionless ring, full of all the stuff that is in the process of falling in but which from out point of view, never will?