Cygnus X-1

Halfway down the Cygnus the Swan's neck lies Cygnus X-1, one of 2 or 3 objects which astronomers believe may be stellar-mass black holes in our galaxy. It is, of course, invisible, and its stellar companion is far too faint to see, but itís existance is well established fron the eclipsing of x-rays from its accretion disk as it circles its companion in a tight embrace. The orbiting of the companion of roughly known mass gives us the 3-4 solar mass of the object and the flickering in its output gives the size, approximately 9 miles diameter. No object except a black hole can be this small and yet so massive.

To answer a frequently asked question: no, we are not being sucked into this black hole: it is no more a danger to us than any other star. While it is the closest known black hole, it is still some 1000 light years distant and no more dangerous than any other star at that distance.

Last Updated October 5, 1995

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