known as ΓÇ£groups.ΓÇ¥ The larger galaxies in this image, particularly the elliptical galaxies, are generally surrounded by a ΓÇ£haloΓÇ¥ of smaller galaxies.
Just as galaxies form groups and clusters, clusters of galaxies are believed to be joined in even larger gravitationally bound systems known as superclusters, which may represent the largest structures in the universe. The cluster seen here is thought to be a local ΓÇ£condensa- tionΓÇ¥ within a supercluster.
Clusters of galaxies seem to lie along filaments and on the surfaces of giant bubbles, the interiors of which, known as voids, are almost completely lacking in visible matter.
Superclusters are not static. There is evidence that the Local
