[/caption] Abell 2744, shown above in a composite of images from the Hubble Space Telescope, the ESO’s Very Large Telescope and NASA’s Chandra X-ray  Observatory, is one of the most complex and dramatic collisions ever seen between galaxy clusters. Dubbed “Pandora’s Cluster”, this is a region 5.9 million light-years across located 3.5 billion light-years away. … Continue reading A Four Cluster Pile-Up