I watched a tv programme recently in which it said astronomers had found that every galaxy had a supermassive black-hole at its centre. What I found curious was the finding that each specific black hole always made up 0.5% of the mass of the galaxy it was located in. There is clearly an inescapable link between a galaxy and its supermassive central black-hole. What is the current reasearch and theories as to why this is? Thanks to anyone who posts on this thread.