The most massive distant object known
Monday, April 11, 2011 - 04:30
in Astronomy & Space
(PhysOrg.com) -- Galaxies often occur in groups. Our own Milky Way galaxy, for example, and its local neighborhood with about fifty galaxies are at the edge of the Virgo Cluster, a collection of somewhere between 1200 and 2000 galaxies. Galaxy clusters are the most massive objects in the universe, and their formation is thought to have begun from small spatial variations in the density of matter in the early universe. Clusters are therefore powerful probes of the growth of structure in the early universe, and their numbers and masses help astronomers test cosmological models including galaxy formation.