Local Group

The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly 3 megaparsecs, and a total mass of the order of 2×10¹² solar masses. It consists of two collections of galaxies in a "dumbbell" shape: the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about 800 kpc and are moving toward one another with a velocity of 123 km/s. The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies. The two largest members, the Andromeda Galaxy and the Milky Way, are both spiral galaxies with masses of about 10¹² solar masses each.

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Unveiling the Cosmic Shadows: Discovering the Local Group’s Hidden Galaxies

Astronomy Jargon 101: Local Group