Astronomers See ‘Best Evidence Yet’ of a Black Hole in the Milky Way

German astronomers said Wednesday they had all but proved there is a massive black hole at the center of our galaxy, the Milky Way. Reinhard Genzel of the Max Planck Institute for Extra-Terrestrial Physics, near Munich, said he remained cautious about claiming absolute proof, but “it was caution backed up by the best evidence that has yet existed,” he said.

The only means of detecting a black hole is by observing its gravitational effects on other objects. Since 1992, scientists at the institute have measured the “proper” motions of 39 stars in the Milky Way at right angles to line-of-sight velocities, they report in the Oct. 3 issue of Nature. Their observations support the assumption that the stars moved in circular orbits around a large central mass with gravitational pull.