The Virgo Supercluster is a large-scale multigalactic structure about 200 million light years in diameter. By comparison, the Milky Way Galaxy is about 100,000 light years across, 2,000 times smaller. The Milky Way, and by extension this solar system and Earth, are a part of the Local Group of galaxies, which in turn is a part of the Virgo Supercluster. It has a diameter about 0.2% the size of the entire visible universe and is one of an estimated 10 million superclusters.
There are approximately 200 galaxy groups, 2,500 large galaxies, 50,000 dwarf galaxies, and 200 trillion stars in the Virgo Supercluster. It is named after the Virgo cluster, the largest nearby galactic structure, which is the dominant gravitational force in the supercluster (and gave it its name). Other large clusters within it include the Fornax cluster and the Eridanus cluster. The Local Group is relatively small in comparison to these larger clusters, although the supercluster is referred to as the Local Supercluster.
The overall structure of the Virgo Supercluster is somewhat similar to the galaxies within it — a flat disc shape surrounded by a diffuse halo. The disc contains about 60% of the luminous galaxies in the supercluster, while the halo contains about 40%. Like all other large-scale structures in the universe (including galaxies), this one is primarily made up of invisible dark matter, which can only be detected by the gravitational influence it holds over other matter.
This structure is located near other superclusters, such as the Pavo-Indus Supercluster, the Centaurus Supercluster, the Perseus-Pisces Supercluster, and many others. It is also bordered by large voids: the Sculptor void, Bootes void, and Capricornus void. On scales larger than superclusters, the curious cellular nature of the universe becomes more noticeable. Luminous matter is primarily condensed into large sheets and filaments straddling the edges of even more enormous voids.
By Michael Anissimov