Quasars are known to be the highly luminous neclei at the centre of the galaxy at large red shifts and they emit energy trillions times more than that of sun in form of gamma rays and other radiations. May I know what are the other radiations?....What are the various ways in which celestial bodies can emit energy? It is believed that the black holes accumulate all the 'dust.gases etc.' around it and this results in enormous amount of energy being emitted because of the high potential energy around the black hole. Is it that when the matter like gas, dust etc is being ACCREDITED towards the black hole , due to the large mass of the matter , the potential energy around black hole is changed and this change in potential energy is emitted as gamma rays etc. ? or is it some other mechanism??