The Andromeda Galaxy, also known as Messier 31, NGC 224, is a spiral galaxy approximately 2.5 million light-years away from Earth. It is in the constellation Andromeda, and it is the nearest spiral galaxy to our own, the Milky Way. Both the Milky Way and the Andromeda Galaxy are members of the Local Group, which also includes the Griangulum Galaxy, among others. Until recently, it was believed that the Andromeda Galaxy had the greatest mass of the three Galaxies in the Local Group, but recent findings suggest that the Milky Way has the most dark matter out of the three, and this fact may suggest that in fact the Milky Way is the most massive.