Sagittarius A* is the supermassive black hole at the center of the Milky Way. As supermassive black holes go, it is fairly quiet. It’s not creating any galaxy-wide tantrums that should worry us. It does flare up though,

A new study suggests more supermassive black holes may be lurking in the universe than previously thought. Astronomers from the University of Southampton have discovered that 35 per cent of these enormous entities—some of which are billions of times heavier than the sun—remain undetected.