Some astronomers detected flashes of x-ray in the cosmos. They say it can only be possible because matters temperature increases to million degrees to radiate into x-rays, and only objects entering into black hole could radiate x-rays in whole cosmos. How can you detected x-ray radiation from lump of material disappearing into black hole? I mean how can even radiation can escape from such strong gravity of black hole, even light(radiation) can't escape from it? Or is it the radiation would form from the matters out of the event horizon of the black hole? Can radiation still be formed out of the event horizon too?