Omega Centauri (NGC 5139)

Omega Centauri (NGC 5139) is a globular cluster in the constellation of Centaurus. It is the biggest of globular clusters of the Milky Way galaxy. The stars of this cluster formed over a 12-billion-year period of time, with several starburst peaks.

Omega Centauri is situated about 18,300 light-years away from Earth and contains several million Population II stars. The stars in its center are very crowded and they are believed to be only 0.1 light years away from each other. NGC 5139 has a total mass of five million Suns and its stars are gravitationally bound into a spherical configuration, with the highest density of stars at the center. Omega Centauri was discovered by Edmond Halley in 1677 who listed it as a Nebula.