Fascinating rhythm: Light pulses illuminate a rare black hole

(University of Maryland) Astronomers have accurately measured -- and thus confirmed the existence of -- a rare intermediate-mass black hole about 400 times the mass of our sun in a galaxy 12 million light years from the Milky Way. The finding, published Aug. 17 in Nature, uses a technique never applied in this way before, and opens the door to new studies of these mysterious objects.