I use the term "black hole" advisedly. The term, arising from GR, implies the existence of an event horizon with finite size. It takes only a very minor adjustment to GR and the event horizon disappears into a singulariy.
Has it occurred to anyone else that a "black hole" might eventually consume all of its original host galaxy and then drift in search of a new host? The fact that we can still see it implies that matter is still being drawn into its center at a considerable rate, so there must be a fairly dense cloud surrounding it. This might be the "black holes" brief swan song before it vanishes from sight.
Maybe, in a collision of two galaxies, one galaxy s*****ed away most of the stars from the other galaxy, and the "black hole" emerged practically nude. Maybe nude "black holes" are the rule, rather than the exception. We don't see most of them because they have run out of fuel; but if we look hard enough, maybe we can detect their gravity-lensing effect. If there is dark matter to be found, this might account for a large share of it.
What happens to the matter when it is "consumed" by a "black hole"? Does it simply grow more massive? We know that some "black holes", at least, spew jets of anti-matter from their polar axes at about 1/2 c. Maybe that is the ultimate fate of most of the matter; after it spins inward faster and faster, it ultimately emerges as anti-matter at 90 degrees to the galactic plane. Eventually, I would guess, the last remnants of matter lack the necessary gravity to continue the process.
Could there be anti-matter galaxies being sucked into "anti-black holes" and converted to regular matter? That would answer the question of where the matter comes from. Since anti-matter looks like regular matter moving backward in time, the entropy accumulated in one system would be reversed in the other. A closed universe with equal amounts of matter and antimatter could maintaim a constant amount of entropy and run forever without running down.
