Nothing can escape a black hole, even light, because to wrench away from its titanic gravitational pull, you’d have to move faster than light is capable of traveling. And nothing can do that, as far as anyone knows. As matter falls into a black hole’s gaping maw, it superheats to millions of degrees, screaming a final cry of X-rays as it is torn apart. At a specific point called an event horizon, the matter disappears and is never heard from again.

A pair of X-ray telescopes recently watched some of these X-ray death gasps and were able to figure out how fast a black hole is spinning. This is “hugely important” for black hole science, according to researchers working with NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR space telescope. One particularly cool finding: The black hole is spinning almost as fast as Einstein’s theory of gravity says it possibly could. It’s spinning at almost the speed of light.