How Can We See Light from Black Holes?

[DurgeshVYadav]

Whenever I see any image of a black hole or in television or anywhere, I found there is a ring of light around the black hole. In discovery channel, I heard them saying that scientist found rings of light in space which had black region inside it. It was also one of the evidence with the help of which we can say that black holes are there in the universe.

My question is that, when we know that black hole has sooo... much of gravity that even light cannot escape from it, how can we see those rings of light ? Means how that light is able to reach our eyes ?

 

[Ryan_m_b]

The ring around a black hole is formed from an accretion disc.

 

[tiny-tim]

Welcome to PF!

Hi Durgesh! Welcome to PF!

The light comes from round the black hole, not from inside it …

matter about to fall into the black hole can emit light,

and also light from objects behind the black hole can get focussed to appear to come from the https://www.physicsforums.com/library.php?do=view_item&itemid=268" at r = 3M

 

[Drakkith]

While any light that is makes it beyond the event horizon will not escape, light that "skims" the surface so to speak is simply bent from its path. The closer the light is to the event horizon the more it is bent. See here: http://en.wikipedia.org/wiki/Gravitational_lens