How can a black hole emit X-rays?

Answer 1

I don't know about x-rays but they do put off gamma rays, that's how we locate them.

Answer 2

Why does a black hole emit X-rays?

It's not really the black hole itself that shines as an X-ray source. Stars and interstellar gas in the vicinity of the hole can be trapped by its powerful gravity.

As matter spirals in toward the hole, much like water flowing down a drain, it heats up to millions of degrees and begins to glow in X-radiation. The disk of material that surrounds a black hole is called an accretion disk.

For lots more info use this link. / http://science.nasa.gov/headlines/y2000/ast26jan_1.htm

Answer 3

Many stars are observed to be in binary systems, where two stars are orbiting each other (as the Earth orbits the sun). Another thing to know is that, the more massive a star is the faster it uses up its nuclear fuel (mostly hydrogen); therefore the sooner it "dies".

If we happen to have a binary star system, and the more massive of the two stars explodes as a supernova and it leaves behind a neutron star or a black hole, then it will result in a binary star system with a normal star and a compact object orbiting each other. All these things working out is rare, but there are over a billion stars in the galaxy, so even rare things happen fairly often.

Now, imagine that the "normal star" then runs out of its fuel. The first thing it will do is expand as it enters its "red giant phase", as our Sun will about 4,000,000,000 years from now. Then, some of the star's outer atmosphere will spill over onto the black hole. It will eventually fall in, and in the process become very hot. We can observe this hot gas with X-ray telescopes, so we call this an X-ray binary.

As far as the significance of the X-ray emission, it is to let us observe the effects of the black hole, and therefore learn something about it. Black holes do not emit light, in fact they are so dense that they trap it. Therefore, the best way to learn about them is by observing the material they effect. Observing X-rays from an X-ray binary is one effective way of doing this.

Answer 4

Black holes themselves do not emit X-rays, but the matter being pulled into them does. As it is pulled closer and closer it accelerates and is distorted by tidal forces, causing it to get very hot, so hot that it emits X-rays shortly before crossing the event horizon and being lost. Because the X-rays are emitted before the point at which the escape velocity exceeds light speed, they can escape and so be detected.

Answer 5

Black holes are very interesting. I found a reference for a kind of black hole who is thought to exist (there´s some evidence for it but it´s still being studied) and it is supposed to emit x-rays.

Hey there´s another article from the hubble site about a kind of Black holes that may emmit X-rays. Hope it helps.

Answer 6

X-rays are a form of light, they can't escape a black hole, however X-rays may escape from the activity of a black hole sucking in a star.

Answer 7

I'll actually answer this question unlike everyone else:

The xrays you are referring to are not really being emitted from the black hole. They are a byproduct of its gravitational affects on matter (heat and pressure of the rotating disk of gas)

Black holes emit hawking radiation but not in the form of xrays.

Answer 8

Hi,
I downloaded Orbitum for free here http://j.mp/1lhvzh0
It's a good free solution

Answer 9

i don't think a black hole emits anything... the only way we can find one, is by looking for stars that have a very fast orbit.... um... but i guess it could... idk..