When I picture them in my mind, black holes are often a swirling vortex of nothing. But I’ll admit that I didn’t actually know how much or how fast they can spin, until now. Turns out there’s a huge black hole about six billion light-years away that’s spinning at half the speed of light.
In a paper published in Nature, astronomers detail how they used the Chandra X-Ray Observatory and the Hubble Telescope to observe x-rays being emitted by the black hole. That examination helped them identify the rate at which matter fell into it, which facilitated their calculations of the speed at which the black hole spins. The region emitting the x-rays is about three times wider than the radius of the center, or event horizon, from which no matter can escape—the size of that region relative to the size of the event horizon indicates how quickly it rotates.