Local Group, in astronomy, loose cluster of at least 35 nearby galaxies galaxy, large aggregation of stars , gas, and dust, typically containing billions of stars. Recognition that galaxies are independent star systems outside the Milky Way came from a study of the Andromeda Galaxy (1926–29) by Edwin P.
..... Click the link for more information. , including our own Milky Way Milky Way, the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky.
..... Click the link for more information. galaxy, the Andromeda Galaxy Andromeda Galaxy, cataloged as M31 and NGC 224, the closest large galaxy to the Milky Way and the only one visible to the naked eye in the Northern Hemisphere. It is also known as the Great Nebula in Andromeda. It is 2.
..... Click the link for more information. , and the Magellanic Clouds Magellanic Clouds (măj'əlăn`ĭk)
..... Click the link for more information. . The Local Group is spread over an ellipsoidal region of space with a major axis of approximately 3 million light-years. The Milky Way galaxy, near one end of the major axis, and the Andromeda Galaxy, near the other end, are the largest members of the group. Some of the galaxies in the group have been detected only by their infrared radiation infrared radiation, electromagnetic radiation having a wavelength in the range from c.75 × 10⁻⁶ cm to c.100,000 × 10⁻⁶ cm (0.000075–0.1 cm).
..... Click the link for more information. ; a dusty region in space obscures their visible light. There may be other galaxies in the Local Group that are as yet undetected. As shown by the work of G. de Vaucouleurs, the Local Group is part of a supercluster containing at least 50 separate clusters, each having from a few dozen to as many as a thousand galaxies. These groups appear to be concentrated in a plane, which indicates that the supercluster is rotating. Its center lies approximately 50 million light-years away in the direction of the constellation Virgo.

Local Group

Concentration of about 50 galaxies to which the Milky Way Galaxy belongs. Nearly one-third are dwarf elliptical galaxies, but the six largest are spiral or irregular galaxies. They are probably kept from separating by mutual gravitational attraction. The Milky Way system is near one end of the group; the great Andromeda Galaxy is near the other end, about two million light-years away.

Local Group [′lō·kəl ′grüp]

(astronomy)

A group of at least 20 known galaxies in the vicinity of the sun; the Andromeda Spiral is the largest of the group, and the Milky Way Galaxy is the second largest.