Omega Centauri is the most massive of all the Milky Way's globular clusters. Sparkling away at magnitude 3.7, appearing nearly as large as the full moon on the southern night sky and located just above the plane of the Milky Way, it is thought to be around 12 billion years old and contain some ten million stars.
Recent research into this intriguing celestial giant suggests that there is a black hole sitting at its centre. Observations showed that stars at the cluster's centre were moving around at an unusual rate — the cause, astronomers concluded, was the gravitational effect of a massive black hole.
The presence of this black hole is just one of the reasons why some astronomers suspect Omega Centauri to be an imposter. Some believe that it is in fact the heart of a dwarf galaxy that was largely destroyed in an encounter with the Milky Way.