Giant Galaxy Cluster CL0958+4702

Monster Galaxy Pileup |  Astronomers have combined data from the WIYN 3.5-meter telescope on Kitt Peak and NASA’s Spitzer and Chandra space telescopes to identify one of the biggest collisions of galaxies ever observed. Four large galaxies have been spotted in the process of tangling and, ultimately, merging into single gargantuan galaxy five billion light-years from Earth.
Yale Press Release | Spitzer Press Release