Twice before, the star system known as PSR 1913+16 has shouted out its presence to the universe. And in a few hundred million years, it may do so once again -- this time as it gives birth to a black hole.
The system consists of two neutron stars -- the crushed cores of once-mighty stars. Each of the stars exploded as a supernova, blasting its outer layers into space and briefly shining brighter than billions of normal stars. Only their dense cores remain.
But as the neutron stars orbit each other, they lose a bit of energy. That makes them spiral closer together -- by about a foot a month. At that rate, they'll slam together in about 300 million years.
The collision may create a brilliant flash of energy known as a gamma-ray burst. It won't last long, but it'll release more energy than the Sun will produce during its entire lifetime. In fact, for a couple of seconds, it'll outshine the combined glow of every other star in the universe.
There are two kinds of gamma-ray bursts. One kind lasts up to several minutes, and is probably produced by the death of a supermassive star.
The other kind is less common, so it's less understood. It lasts no more than two seconds, and leaves behind almost no trace. The leading theory says these short bursts occur when two neutron stars merge to create a black hole. If so, then the stars of PSR 1913+16 will have one more moment of glory -- followed by an eternity of darkness.
Script by Damond Benningfield, Copyright 2008
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