Galaxies are the building blocks of the universe. Clusters of galaxies, and clusters of clusters of galaxies, called superclusters, make up the structures in the geography of the universe. In this ...

"This discovery poses a challenge to the Lambda Cold Dark Matter model, which may struggle to account for the formation of such small, aligned groups of galaxies in isolated environments.

Current models suggest that these massive structures form as clumps of dark matter and the galaxies that form within them are pulled together by gravity to form groups of dozens of galaxies ...