Messier 31, also known as the Andromeda Galaxy, is the nearest spiral galaxy to the Milky Way and is located about 2.537 million light-years away from Earth. It is one of the largest galaxies in the local group, which includes the Milky Way, Triangulum Galaxy, and several smaller galaxies. The Andromeda Galaxy has a diameter of approximately 220,000 light-years and contains around one trillion stars. It is visible to the naked eye from Earth and can be found in the constellation Andromeda. In the distant future, it is expected to collide with the Milky Way, resulting in a new galaxy formation.