Mystery Solved: Black Holes Twist Space-Time Like Taffy
http://www.space.com/33598-black-hole-flicker-mystery-solved.html
A 30-year-old mystery about black holes has just been solved.
The story starts in the 1980s, when astronomers found that small (stellar-mass) black holes emit X-ray light that flickers in a curious pattern. At first,
this flickering occurs every few seconds; however, the time between each flicker shortens over the course of a few months, eventually stopping completely.
This "quasi-periodic oscillation" (QPO) was thought to be a result of a phenomenon predicted by Albert Einstein's theory of general relativity — that any
object with enough mass, like a black hole, will twist space-time as it spins. Later, scientists calculated that these gravitational vortices will cause
the orbits of particles around the black hole to change orientation, leading to the QPO phenomenon.
