银河系中心隐藏黑洞或解开恒星之谜

THE centre of our galaxy is a strange and chaotic place, but we may finally have an explanation for the unusual stars that orbit there. Our supermassive black hole, Sagittarius A*, is surrounded by three populations of stars, all strikingly different from one another but with similar ages, and researchers have come up with a relatively simple model that can explain all of them at once. The closest objects to Sagittarius A* are called S-stars: a spherical swarm of stars, many of which are on elongated orbits that take them dangerously close to the black hole. Their distribution also has a strange, unexplained gap called a zone of avoidance. …