The Andromeda Galaxy, also known as M31, is the nearest spiral galaxy to the Milky Way and is on a collision course with our galaxy. It is approximately 2.537 million light-years away and contains over a trillion stars, making it one of the largest galaxies in the Local Group. Visible to the naked eye from Earth, the Andromeda Galaxy appears as a faint smudge in the night sky. It is named after the princess Andromeda in Greek mythology, reflecting its historical significance in astronomy and its prominence in the study of galaxies.