Coma Cluster (uncropped view)

The Dark Energy Camera captures an image of the dazzling Coma Cluster, named after the hair of Queen Berenice II of Egypt. Not only significant in Greek mythology, this collection of galaxies was also fundamental to the discovery of the existence of dark matter. The theory emerged in 1937 when Swiss astronomer Fritz Zwicky noticed that the Coma Cluster galaxies behaved as if they were under the influence of vast amounts of unobservable ‘dark’ matter.

See a cropped version of this image here.