Jun 1, 2017
Abell 2744, Pandora’s Cluster of Galaxies
Abell 2744, nicknamed Pandora's Cluster, is a giant galaxy cluster resulting from the simultaneous pile-up of at least four separate, smaller galaxy clusters that took place over a span of 350 million years.[1] The galaxies in the cluster make up less than five percent of its mass.[1] The gas (around 20 percent) is so hot that it shines only in X-rays.[1] Dark matter makes up around 75 percent of the cluster's mass.