Hubble Peers into the Most Crowded Place in the Milky Way
This Hubble Telescope image shows the Arches Cluster, the densest star cluster in the Milky Way. It is located about 25,000 light-years from Earth in the constellation of Sagittarius. It is a relatively young star cluster between two and four million years old. The Arches cluster is so dense that in a region with a radius equal to the distance between the Sun and its nearest star there would be over 100,000 stars. At least 150 stars within the cluster are among the brightest ever discovered in the Milky Way.
These stars burn their fuel within a few million years, expiring in supernova explosions. Due to their short lifetime the gas between the stars contains a high amount of heavier elements, the residue of earlier generations of stars.