New Evidence Suggests Black Holes Spin

May 1 -- Black holes, the hungry pockets of intense density in space, don't only suck; some also appear to spin like whirlpools, a NASA scientist recently announced.

"Almost everything in space spins, but it's been easier to detect the spin of stars and planets," explained Todd Strohmayer, a NASA astrophysicist. "Since you can't see black holes the only way to detect their spin is by observing the motion of material close to it."

Scientists believe the black hole Strohmayer studied formed when a star grew to such bulk it collapsed upon itself. The resulting collapsed matter formed a single point of infinite density that sucks in surrounding matter and even light.

Patterns Show Spin

While the black hole is not visible by light, Strohmayer and his team found patterns in radiation around the black hole that, when calculated with the known mass of the black hole (which is seven times the mass of the sun), suggest it is in spinning motion.

According to Einstein's equations of general relativity, a spinning black hole would allow matter to approach closer before being drawn in by its powerful suction.

"Because we know the mass and can infer how rapidly material is moving around the black hole, we can infer the only way the material is moving in that way is if the hole is spinning," said Strohmayer.

Astronomers have observed similar patterns in X-rays emanating from around neutron stars — stars that have collapsed after growing to nearly as large proportions as those that form black holes. Scientists believe the patterns are formed by hot gas flickering in orbit around spinning stars and just at the edge of the stars' attracting force. The spinning motion of the stars permit the gas to approach closer to the stars just before falling in.

Strohmayer suspects the flickerings he has observed 10,000 light years from Earth could be formed by hot gas dancing around the edge of the powerful suction of a spinning black hole. His team made the observations using NASA's Rossi X-ray Timing Explorer, an X-ray satellite launched in 1995, and he announced his findings at a meeting of the American Physical Society.