Posted: Thu, Sep 1, 2011, 7:24 AM ET (1124 GMT)

Astronomers announced Wednesday the discovery of the closest pair of supermassive lack holes found to date, in a galaxy 160 million light-years away. The black holes, each with a mass a million times that of the Sun, are located in the galaxy NGC 3393; astronomers were able to determine that two black holes, rather than one, are present there using observations by the Chandra X-Ray Observatory. Astronomers believe the black hole pair was created at least a billion years ago when the spiral galaxy merged with a smaller galaxy, incorporating the supermassive black hole at its core.