Echoes Reveal Burst of Activity from Milky Way's Supermassive Black Hole 200 Years Ago.

Astronomers have detected an echo of X-ray emissions from the Milky Way's central supermassive black hole, Sagittarius A*, that occurred 200 years ago. The black hole had a brief period of activity and consumed nearby material, resulting in X-ray emissions that were more than a million times greater than usual. The emissions were detected by NASA's Imaging X-ray Polarimetry Explorer (IXPE) and were found to be the source of the brightening of nearby molecular clouds. The discovery could help astronomers better understand the behavior of Sagittarius A* and the causes of its flares.