APOD 4.4 NGC 5139: Omega Centauri

This picture is quite stellar, literally. Shown here is the largest known globular cluster in our galaxy. Omega Centauri is in the constellation Centaurus, a constellation that holds many wonders including the closest star system-Alpha Centauri. Omega Centauri is a wonder in itself. Most globular clusters are made out of old stars but Omega consists of a range of ages. In fact with it consisting of over 10 million stars and 150 light-years across, it may be the remnant of the core of a smaller galaxy that has merged with our own Milky Way.