1) Galaxy cluster
Found on
https://www.crosswordclues.com/clue/hydra-cluster
The Hydra Cluster (or Abell 1060) is a galaxy cluster that contains 157 bright galaxies and can be viewed from earth in the constellation Hydra. The cluster spans about ten million light years and has an unusual high proportion of dark matter. The cluster is part of the Hydra-Centaurus Supercluster located 158 million light years from earth. The c...
Found on
http://en.wikipedia.org/wiki/Hydra_Cluster
No exact match found.
