Local Group. Diagram showing the positions of the members of the Local Group cluster of galaxies, relative to the plane (grid) of our Milky Way Galaxy (centre left). Dotted blue lines show the galaxies that are below this plane, and solid blue lines show the galaxies above this plane. Sixteen of the more than 30 members of the Local Group are shown. The Local Group occupies a volume about 10 million light years in diameter. The Milky Way and M31 (Andromeda Galaxy, centre right) are the most massive of these galaxies, and have each acquired a system of satellite galaxies. The nearest to the Milky Way Galaxy are the Small Magellanic Cloud (SMC) and Large Magellanic Cloud (LMC).