Saw an article in the Baltimore Sunpapers today. Scientists at Johns Hopkins and Penn State University believe that Black Holes are "like cockroaches". They believe there are more of them than you can imagine. They estimate over 200 million of them.
Thank god our SE4 universe doesn't have quite so many.
I'm not sure if they mean the entire galaxy or not, the story is not clear. They talk about a "Deep Field North" observed by the orbiting Chandra x-ray observatory. They think some of the x-rays began their journey toward earth ~9 billion years ago.