How fast can a black hole turn?
If any object made of regular matter rotates too fast, disintegrates. But a black hole could not be able to disintegrate, and its maximum turn speed It is really unknown.
Theorists generally model the black holes that turn quickly with Kerr’s solution to the general theory of Einstein’s relativity, which predicts several amazing and unusual things.
However, perhaps its most easily verifiable prediction is that the matter that enters a black hole of maximum rotation should be seen for the last time orbiting near the speed of light, as seen from afar.
This prediction was tested by NASA and XMM Nustar satellites of the ESA when observing the supermassive black hole in the center of the NGC 1365 spiral galaxy.
The limit close to the speed of the light was confirmed by measuring the heating and widening of the spectral line of nuclear emissions on the inner edge of the surrounding accretion disc.
Here is a normal matter accretion disk that revolves around a black hole, with a stream that emanates from the top.
