101 Giant Galaxy Clusters Discovered

Porfiry says: "Astronomers behind the Massive Cluster Survey (MACS) have uncovered 101 giant galaxy clusters, many of them so distant and thus forming so early in the history of time that they challenge our current understanding of how quickly the Universe evolved into its current hierarchical structure of stars, galaxies and clusters. Galaxy clusters are the largest gravitationally bound structures in the Universe, typically containing a few hundred to thousands of galaxies, each of which in turn contains many billions of stars."