NASA recently published a video simulation of what it would look like flying into a black hole (video can be seen here ).
What confuses me is that it appears to show the photon ring around the black hole as being visible from a distance. How is that possible?
"Seeing" a star or any visible light from space means that the corresponding star photon has travelled through space and reached the eye retina. However, I thought the photon ring around the black hole consists of photons that have been caught by the massive gravitational pull of the black hole and therefore cannot escape: rather, they keep rotating around the hole. Therefore, they cannot travel "away" and reach the eye retina of a distant observer.
Surely, one would only notice the photon ring when flying through it (i.e. reaching the ring and intersecting it: then the rotating photons could penetrate the eye retina).
Am I wrong in my assumptions?