- The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly 3 megaparsecs (10 million light-years; 9×1022 metres), and a total mass of the order of 2×1012 solar masses (4×1042 kg). 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 (3×106 ly; 2×1022 m) 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.
- Star Tales - Coma Berenices (ianridpath.com)
Between Boötes and Leo lies a fan-shaped swarm of faint stars that was known to the Greeks but was not classed by them as a separate constellation. Eratosthenes referred to this swarm as the hair of Ariadne under his entry on the Northern Crown (Corona Borealis), but under Leo he said it was the hair of Queen Berenice of Egypt, which is how we identify it today.