Astronomers have calculated the mass of the heaviest stellar black hole in our galaxy in a discovery that turns the accepted theory of how such objects are formed and behave on its head.

Scientists at the Astrophysical Institute in Potsdam, Germany, and the European Southern Observatory in Chile said the huge black hole has 14 times more mass than the sun and is in a remote area of the Milky Way almost 40,000 light years away. A light year is about six trillion miles (10 trillion km).

The black hole and the star that revolves around it and feeds it are in the stellar system called GRS1915+105.

Black holes suck in everything near them including light and can only be detected by the activity around their edges. Stellar black holes, the remnants of dead sun-like stars, typically have the mass of three to seven suns.

The distance between the star and the black hole is about half the distance between the Earth and the sun.

The size of GRS1915+105, which astronomers have dubbed a microquasar, has cast doubt over the theories on how black holes are formed. Scientists consider microquasars, binary systems consisting of a normal star and a black hole or neutron star, as natural laboratories for testing Einstein's general theory of relativity.

GRS1915+105 is one of a handful of microquasars in our galaxy. Scientists are puzzled by the size of the black hole because the interaction in a binary system increases the mass loss of the star and they don't know how it can retain enough mass to form such a massive black hole.


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Khorsheed.com - Jan 2002