Scientists confirm that the first black hole ever imaged is actually spinning::The first black hole humanity has ever imaged has also provided us with what researchers are calling “unequivocal evidence” that black holes spin.
Scientists confirm that the first black hole ever imaged is actually spinning::The first black hole humanity has ever imaged has also provided us with what researchers are calling “unequivocal evidence” that black holes spin.
I see. Thank you. So, you can use light to infer the mass, and then the volume information to infer the spin? Easy enough.
That would be a general method, if we were close enough to observe the shape of the event horizon (which we aren’t).
The article is describing another way, which only works in this case because the black hole is precessing so extremely that the changing axis of rotation is frame-dragging the polar jets along with it.