Swirling gas helps scientists nail down Milky Way's supermassive black hole mass

An image of the supermassive black hole at the center of the Milky Way, a behemoth dubbed Sagittarius A*, revealed by the Event Horizon Telescope on May 12, 2022.

At the center of our galaxy sits a dark enigma, a supermassive black hole named Sagittarius A*. Astronomers have known about the existence of Sgr A* for some time, and even snagged a spectacular image of it in 2022, but getting exact measurements of its size and activity has proven difficult.

Now, according to new findings from the Max Planck Institute for Extraterrestrial Physics (MPE), a group of astronomers has determined, with high accuracy, the mass and radius of Sgr A*.