Astronomers know that the tremendous gravitational pull of a black hole sucks matter in. They also know that the material falling in causes powerful jets of particles to shoot out of the black hole at nearly the speed of light. But how exactly this phenomenon occurs remains a matter of conjecture, because astronomers have never quite managed to observe the details.

 

Well, now they have. Sheperd Doeleman, an astrophysicist at the Massachusetts Institute of Technology Haystack Observatory in Westford, and his colleagues have taken the closest look to date at the region where matter swirls around a black hole. By measuring the size of the base of a jet shooting out of the supermassive black hole at the center of the M87 galaxy, the researchers conclude that the black hole must be spinning and that the material orbiting must also be swirling in the same direction. Some of the material from this orbiting “accretion disk” is also falling into the black hole, like water swirling down a drain. The finding appears online today in Science.

 For the past few years, Doeleman and his colleagues have been working to link up radio dishes around the world into a virtual telescope with unprecedented magnifying power, which would enable researchers to observe the immediate vicinity of the black hole in the heart of M87—a favorite target for astronomers, as it is one of the brightest objects in the sky. So far, the researchers have linked radio dishes at three sites. That hasn’t provided enough resolution to see all the way to the edge of the black hole. But it enabled the researchers to measure the area through which the jet is being emitted.