The galaxy cluster nicknamed Pandora’s Cluster is formally known as Abell 2744.
Abell 2744 is a massive galaxy cluster formed through the merger of at least four smaller galaxy clusters. Astronomers gave it the informal name Pandora’s Cluster because the collision produced a complicated mixture of structures and phenomena, much as the mythological container released many different troubles.
The cluster lies about 3.5 billion light-years from Earth. Observations combining visible light, X-rays, and gravitational lensing have helped researchers separate its galaxies, hot gas, and dark matter. The cluster became an important target for coordinated observations, including the Frontier Fields program, which used massive clusters as natural telescopes.
Abell 2744 is not the same object as the Bullet Cluster, another famous merging galaxy cluster. Both provide evidence about the distribution of dark matter, but they have different formal designations and merger histories. The Abell number comes from George O. Abell’s catalog of rich galaxy clusters.