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Faraway black hole spins at half the speed of light

Reuters

A supermassive black hole inside a distant quasar spins at about 336 million mph (540 million kph), roughly half the speed of light, according to research published in the journal Nature.

Scientists have measured the spin rates of black holes before, but never one so far away. The newly measured black hole is inside a quasar some 6 billion light-years from Earth.

A black hole is a region of space so packed with matter that not even photons of light can escape its gravitational grip. It leaves evidence of its existence as it encounters and swallows cosmic neighbors.

Computer models show that how fast a black hole spins depends on how much material is available for it to consume. A black hole with a steady supply of gas spins faster than one whose feedings are more erratic. The one at the center of our Milky Way is currently on a starvation diet.

The speed of the supermassive black hole inside quasar RX J1131-1231 indicates that it is feeding steadily, most likely on a diet of shredded neighbor galaxies, said Mark Reynolds, an astronomer with the University of Michigan.

It regularly consumes the equivalent of about 333,000 Earths every year, he added.

Scientists want to measure the spin rates of even farther supermassive black holes to see how conditions were different earlier in the history of the universe.

“The ability to measure black hole spins over a large range of cosmic time should make it possible to directly study whether or not the black hole evolves in step with its host galaxy,” said Rubens Reis, also an astronomer with University of Michigan.

The measurements were not easy to make. Analyses of X-rays pouring from near the mouth of RX J1131′s black hole were only possible because a closer galaxy sits between the quasar and Earth-orbiting X-ray telescopes.

The closer galaxy, located about 3 billion light-years from Earth, bends light from the more distant quasar, bringing it into focus like a zoom lens on a camera or telescope. The process is known as “gravitational lensing.”