Distance measurement is key to producing first "complete description" of a black hole

Scientists’ have been able to reconstruct the history of Cygnus X-1 from its birth some six million years ago.

By NRAO, Socorro, New Mexico — Published: November 18, 2011

Artist's conception of Cygnus X-1: Black hole draws material from companion star (right) into hot, swirling disk. Chandra X-Ray Observatory/NASA

For the first time, astronomers have produced a complete description of a black hole, a concentration of mass so dense that not even light can escape its powerful gravitational pull. Their precise measurements have allowed them to reconstruct the history of the object from its birth some six million years ago.
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