A galaxy is a group of stars and gas that are bound together by a common force called gravitation. They are formed as the result of the collisions of stars and are located in the space between the Milky Way and the Sun. While most galaxies are circular in shape, some are irregular and contain many galaxies. A few are even larger than the Milky Way and contain billions of stars. These objects are held together by gravity.
A galaxy can be either a spiral or a sphere. A star in a sphere can be in any direction, so the name comes from a Greek word meaning “milk”. The accretion disk, or halo, of a galaxy, contains a dense layer of dust. These particles are able to travel a considerable distance. When a galaxy is compact, it may contain billions of stars. A stellar mass of over a trillion stars can be found in the Milky Way.
A galaxy can be defined by its mass. There are several kinds of galaxies. Some are quiet and quiescent, while others are vigorously active. Some of them are comprised of billions of stars. These black holes are presumably supermassive and could be black holes. These objects are called clusters. If you have seen a cluster of stars, you have probably observed the same one. The difference is that a clump of stars may not be circular.