Omega Centauri is probably the remnant nucleus of a small galaxy that merged with the Milky Way.
What do we see in today’s NASA image?
The globular star cluster Omega Centauri, also called NGC 5139, is 15,000 light-years away. This cluster contains 10 million stars much older than the Sun in a volume 150 light years in diameter. NGC 5139 is the largest and brightest known globular cluster among the 200 globular clusters located in the halo of the Milky Way.
Most star clusters consist of stars of the same age and composition, but the mysterious Omega Centauri contains stars of different ages and chemical abundances. The stars of the red giant Omega Centauri (in yellow) are easily recognizable in this telescopic image.