At such high temperatures, the material should glimmer gamma rays; but although ions are easy to heat up, they would rather transfer their energy by collisions to better emitters, like electrons. Electrons furnish photons at lower energies, such as x-rays. A blackbody spectrum is so dense that photons cannot abandon it without participating in numerous collisions with electrons. The collisions scatter, destroy, and create photons, obscuring the original source of radiation and averaging out the details of each interaction. "The inferred temperature for the x-ray binaries is ten to the seventh degrees, which is consistent with that expected for a black hole because of its great mass," (Sullivan 34). To generate the observed emission, a hole would need to swallow or accrete the same amount of mass per year. This agrees with estimates of how quickly the ordinary star is losing mass to its companion, the black hole. Thus, x-ray binaries could be the best proof that stellar-mass black holes exist. .
Black holes are the most compact objects in the universe. Near galactic centers, stars are moving so rapidly that they would fly off unless the gravity of a huge mass, up to the equivalent of a billion suns, held them. whatever has this mass must be extremely dense because black holes are estimated at six kilometers wide, while our sun is 1.4 million kilometers wide. The mass of a hole is determined by the way it formed. In particular, by the mass of the star from which it developed and by the amount of matter it has swallowed. Great mass-produce so much curvature that the space would close up around the star, thus forming a black hole. No principle of physics determines how massive a black hole is capable of being. The mass of any object, except a black hole, is limited by its ability to hold up under its own weight.
Black holes have such intense gravity nothing, even at the speed of light, can escape.
