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Black Hole Bullets

March 28, 2012

A black hole near the center of the galaxy is firing bullets. Once every eight months or so, it shoots a “bullet” of plasma -- matter that’s so hot that its atoms are ripped apart. The bullets race into space at a quarter of the speed of light.

The black hole is about 28,000 light-years away, in the constellation Scorpius. It’s probably about 5 to 10 times the mass of the Sun. And it has a companion star that probably resembles the Sun. The two are so close together that the black hole pulls gas off the surface of the companion, which forms a spinning disk around the black hole. The gas gets so hot that it produces X-rays, although the intensity of the X-rays varies.

Three years ago, astronomers monitored the system with radio telescopes on the ground and an X-ray telescope in space. They found that shortly after the intensity of the X-rays peaked, the black hole fired two bullets into space. The bullets followed “jets” of charged particles that shoot into space from the poles of the black hole.

The most likely scenario is that gas piles up in the disk around the black hole, forming a dense knot. Just before it reaches the black hole itself, the knot is blasted into space.

There are several ideas for how that happens, but all of them have problems. Watching the whole process of such an eruption is helping astronomers narrow the list -- and explain how a black hole fires bullets into the galaxy.

More about black holes tomorrow.


Script by Damond Benningfield, Copyright 2012


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