Even though the black hole at the center of the Milky Way is a monster, it’s still rather quiet. Called Sagittarius A*, it’s about 4.6 million times more massive than our Sun. Usually, it’s a brooding behemoth. But scientists observing Sgr. A* with the Keck Telescope just watched as its brightness bloomed to over 75 times normal for a few hours.
Supermassive black holes exist at the center of most galaxies, and our Milky Way is no exception. But many other galaxies have highly active black holes, meaning a lot of material is falling into them, emitting high-energy radiation in this “feeding” process. The Milky Way’s central black hole, on the other hand, is relatively quiet. New observations from NASA’s Stratospheric Observatory for Infrared Astronomy, SOFIA, are helping scientists understand the differences between active and quiet black holes.