Q&A: Black Holes
In one of your pictures you explain that the bright lights
are black holes. I have always been told that black holes
cannot be seen. Could you please explain this to me?
No light of any kind, including X-rays, can escape from
inside the event horizon of a black hole. The X-rays Chandra
observes from the vicinity of black holes are from matter
that is very close to the event horizon of black holes.
Matter is heated to millions of degrees as it is pulled
toward the black hole, so it glows in X-rays.