Case for Massive Black Hole Strengthened

UCLA astronomer Andrea Ghez announced more than four years ago that a monstrous black hole resides at the center of our Milky Way galaxy, 24,000 light years away, with a mass more than 2 million times that of our sun. Some astronomers greeted the announcement with skepticism, and proposed exotic forms of matter as alternatives. At the American Association for the Advancement of Science meeting Feb. 16 in Denver, Ghez reported that the case for the black hole has been strengthened substantially, and that all of the proposed alternatives can be excluded.