Andromeda Galaxy
The Andromeda Galaxy, also known as Messier 31 or M31, is a spiral galaxy located approximately 2.537 million light-years away from Earth in the Andromeda constellation. It is the nearest spiral galaxy to the Milky Way and is the largest galaxy in the Local Group of galaxies, which also includes the Milky Way, the Triangulum Galaxy, and about 54 other smaller galaxies. The Andromeda Galaxy is estimated to contain around one trillion stars, making it more massive than the Milky Way. It is visible to the naked eye from Earth and has been studied extensively by astronomers due to its proximity and similarities to our own galaxy.