This cluster of stars seen in this space wallpaper is known as Messier 15. It is located some 35,000 light-years away in the constellation of Pegasus (The Winged Horse). Messier 15 is one of the oldest globular clusters known, with an age of around 12 billion years. Both very hot blue stars and cooler golden stars can be seen swarming together in the image, becoming more concentrated towards the cluster's bright center. Messier 15 is one of the densest globular clusters known, with most of its mass concentrated at its core. As well as stars, Messier 15 was the first cluster known to host a planetary nebula, and it has been found to have a rare type of black hole at its center. This image was released Nov. 14, 2013.
(Image: © NASA, ESA)