Clusters of Galaxies (IMAGE) Princeton University Caption This image shows some of the 70,000 luminous galaxies in the Sloan Digital Sky Survey analyzed in this paper. Credit Sloan Digital Sky Survey Collaboration Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.