 whizzing around the black hole. She says the only other place astronomers have seen this is at the center of our Milky Way around the supermassive black hole that lives there. Such supermassive black holes are mysterious. Scientists aren't sure when and how they grew so large. Green says being able to study less massive ones like this new one could provide clues about how these enormous monsters came to be. Nell Greenfield-Boyce, NPR News.