Tuesday, February 16, 2010

Backward black holes control fate of galaxies

Image: Black holeThe backward spin of a number of black holes could create mysterious jets of plasma that control the fate of galaxies, scientists now suggest.

At the heart of galaxies, astronomers have routinely detected what seem to be supermassive black holes millions to billions of times the mass of our sun. Roughly a hundredth of these giants spew out jets of plasma that extend out in opposite directions.

These jets control how stars and other bodies form by injecting huge amounts of energy into the universe, playing a crucial role in the evolution of clusters of galaxies, the largest structures in the universe. However, it remains a mystery as to how these jets form.

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To investigate the origin of these powerful jets, scientists compared several dozen galaxies whose super-massive black holes spit jets to other galaxies whose black holes don't. All these black holes featured accretion disks — clumps of gas and dust whirling into the maws of these dark objects. Scientists have long known that black holes spin.

Relying on data collected by a Japanese space telescope dubbed Suzaku, researchers found that jets might form right outside black holes that spin in the opposite direction from their accretion disks. Such retrograde spin could warp space-time in a way that forces the innermost portions of accretion disks outward, leading to "a piling of magnetic fields that provides the force to fuel a jet," said researcher Dan Evans at MIT¹s Kavli Institute for Astrophysics and Space Research.

via Backward black holes control fate of galaxies - Space.com- msnbc.com.

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