Yeh i think that is the general hypothesis. I think if i do remember correctly which remains to be seen that black hole does radiate energy as photons and such and that a small black hole say less than a solar mass will eventually shrink and disappear. However black holes of this size are yet to be identified although theorised to have been created early on in the universes history, but that even the smallest should only now be disappearing. to be honest i don't know how much of this i am remembering correctly.
In a massive black hole however say the one said to exist at the centre of our galaxy they have a constant source of matter which they absorb, increasing their mass so that they absorb more "energy" than they radiate off. If this is the case then will the black hole at the center of our galaxy eventually engulf the milky way.
What happens then though? Is the great attractor to which our own local group, and supercluster is speeding towards an enormous black hole which will engulf our galaxy or perhaps by then our milky way black hole. If this is the case could that be what our Universe ends up being a series of immense balck holes seperated by distances beyond which gravity cannot over come the expansion of space time. Bearing in mind that i am talking about a timeline of several times the age of the current universe.
That was confusing even to me.
