Galaxies stretch from edge to edge in this Hubble Space Telescope image of the Coma Cluster, a collection of more than 1,000 galaxies that spreads across Coma Berenices and adjoining constellations. The two large galaxies are NGC 4889 (left) and NGC 4874. The cluster also contains vast amounts of dark matter, which produces no energy on its own but exerts a gravitational pull on the visible galaxies around it. The cluster is centered more than 300 million light-years away. [NASA/ESA/J. Mack/J. Madrid, et al.]