Clusters of Galaxies

Galaxies contain tens or hundreds of billions of stars like the Sun and all this mass attracts nearby galaxies. They gather in general to form clusters of galaxies and sometimes even clusters of galaxies that are called superclusters of galaxies.

They can gather a handful of galaxies like the mass of the Big Dipper or the Lion (see photos above) but some can count tens of thousands of members! Thus the Milky Way is part of the Local group which also includes the Andromeda galaxy M31 as well as these two satellites M32 and NGC 205, the galaxy M33 of the Triangle, NGC 147, NGC 185 and about forty other dwarf galaxies. They are distributed over a distance of about 2 million light-years.

Finally, the local cluster at the center of which is the Milky Way is surrounded by about twenty small clusters and about thirty isolated galaxies and forms the Superamas of the Virgin, also called Local supercluster. It stretches for about 25 million light-years. The Local cluster is on the edge of this structure whose center is 600 million light-years away from the Milky Way.