You know the saying: nothing, not even light can escape a black hole. That makes them invisible. Amazingly, researchers from the University of Maryland have determined how fast a supermassive black hole is spinning. You won’t be surprised to know it’s spinning insanely fast, at the limits predicted by relativity. The researchers used ESA’s XMM-Newton … Continue reading "Supermassive Black Holes Spin at the Limits of Relativity"