Messier 5 or M5 (also designated NGC 5904) is a globular cluster in the constellation Serpens. It was discovered by Gottfried Kirch in 1702. Spanning 165 light-years in diameter, M5 is one of the larger globular clusters known. At 13 billion years old it, M5 is also one of the older globulars associated with the Milky Way Galaxy. Its distance is about 24,500 light-years from Earth and the cluster contains more than 100,000 stars, as many as 500,000 according to some estimates. (Wikipedia)