Question: how many black holes have been recorded so far?

Sam Connolly answered on 16 Jun 2014:

Loads! I don’t know what the exact number is, because people find new ones all the time, but there are hundreds that have been studied. We think there is a supermassive black hole at the centre of every galaxy though, which means there are billions of those, because we can see billions of galaxies! Also, there are hundreds of smaller ones in our galaxy, plus we’ve seen a few in other galaxies, so there are probably hundreds, or thousands, of smaller ones in every galaxy. So there a lot still to find!