What is the Andromeda Galaxy? The Andromeda Galaxy, scientifically known as Messier 31 or M31, is the largest spiral galaxy in our Local Group and the closest neighbor to our Milky Way. With more than one trillion stars inside it, Andromeda is approximately twice as large as our own galaxy and represents one of the most fascinating objects in the observable universe. Its name comes from the Andromeda constellation, in whose direction it can be observed from Earth. In fact, it is one of the few extragalactic objects visible to the naked eye under ideal dark-sky conditions, appearing as a faint, elongated smudge in the night sky. How far is…