The final plunge

A gas cloud has been spotted approaching the Milky Way's central black hole. Observations of its closest approach, expected to occur in mid-2013, may offer insight into the black hole's immediate surroundings. See Letter p.51 The radio source Sgr A* in Sagittarius is thought to be the site of a supermassive black hole lying at the centre of the Milky Way. A study of stellar orbits has identified an object moving towards Sgr A* at a speed of 1,700 kilometres per second. Its low temperature and spectral properties suggest that it is a dusty cloud of ionized gas, three times the mass of Earth, in the process of falling into the black hole. Models predict that as the cloud gets closer to the black hole, X-ray emissions will become much brighter, and a giant radiation flare may be emitted in a few years if the cloud breaks up and feeds gas into the black hole.