By Space.com – 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. [Images: Black Holes of the Universe]

“It is a bit like twisting a spoon in honey: Imagine that the honey is space, and anything…