Cluster Of Galaxies
A system of galaxies containing from a few to a few thousand member galaxies
which are all gravitationally
bound to each other.
Galaxy groups
and clusters are the largest known gravitationally
bound objects to have
arisen thus far in the process of cosmic structure formation. They form the
densest part of the large scale structure of the universe. In models for
the gravitational formation of structure with cold dark matter, the smallest
structures collapse first and eventually build the largest structures, clusters
of galaxies. Clusters are then formed relatively recently between 10 billion
years ago and now. Groups and clusters may contain from ten to thousands of
galaxies. The clusters themselves are often associated with larger,
non-gravitationally bound, groups called superclusters.
Source: wikipedia, NASA
No comments:
Post a Comment