Black holes don't emit any radiation (except for an insignificant amount of Hawking radiation). However, if matter falls onto a black hole, it will emit x-rays before it reaches the event horizon (the point of no return), as a result of an enormous acceleration.
Black holes emit so very little radiation they are hard to see. Many black holes lie at the center of galaxies and there they are hidden by stars and dust.
Due to light being unable to escape the black hole, we cann't see it! It's like trying to see in a dark room with a flashlight, that has dead batteries. You cann't see the light because their is none to reflect.
The whole idea of black holes is that nothing, not even light, can escape from them. However, there are several indirect ways to detect them.
Black Holes are mostly located at Star's that have Died or Exploded from running out of heat or in which cases The Sun that hasent ran out of energy yet or other stars, you get what i'm saying
You can't see a black hole.
You can't see a black hole.
Scientists can detect black holes by using x-rays and gamma rays. Black holes still can release matter, and black holes give off a lot off x and gamma rays.
After the black hole dies out, (see When do black holes die and/or How does a black hole get smaller) it will become just a vacuum.
Black holes does emit radiation, but they cannot be detected from earth. We use gravitational lensing to "see" the black holes.
Black holes are blavk because their gracity is so strong that light cannot escape for us to see.
If a star is younger in years than it is distant in light years we will not see it. It is there but because of its age and distance the star will be unseen as the light emitted from it has not reached us. Also black holes which use to be stars are 'invisible' as they do not emitt or reflect light.
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