Posted: Thu, Sep 6, 2001, 3:54 PM ET (1954 GMT)
Observations from the Chandra X-Ray Observatory have given astronomers the first direct evidence that a supermassive black hole exists in the center of the Milky Way galaxy. Astronomers announced Wednesday that Chandra had observed an X-ray flare from the vicinity of Sagittarius A*, a source of radio emission astronomers had believed to harbor a black hole. The flare appears to be emission from material in the black hole's accretion disk as it was heated shortly before plunging into the black hole. Astronomers had assumed for years that a supermassive black hole, with a mass several million times that of the Sun, existed in the center of the galaxy based on observations of stars rotating around the center, but until now lacked direct evidence of the hole's existence. The announcement was made at a conference on Chandra science in Washington and also published in Thursday's issue of the journal Nature.
