Spiral galaxies are twisted collections of stars and gas that often have beautiful shapes and are made up of hot young stars. They are characterized by a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge.
The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly 3 megaparsecs and contains more than 54 galaxies, dominated by the Andromeda Galaxy and the Milky Way.