Which DSO (Deep Sky Object) is known for being the closest spiral galaxy to the Milky Way?

The Andromeda Galaxy is recognized as the closest spiral galaxy to the Milky Way, located approximately 2.537 million light-years away. It is part of our Local Group of galaxies and serves as a significant object of study due to its proximity and resemblance to our own Milky Way in terms of structure and composition. The Andromeda Galaxy is classified as a spiral galaxy and has a similar size and shape to the Milky Way, making it an essential counterpart for understanding our galaxy's characteristics and dynamics.

The proximity of the Andromeda Galaxy allows astronomers to conduct detailed observations, enhancing our knowledge of galaxy formation and evolution. It is often the subject of both amateur and professional astronomical studies, contributing to its status as a well-known deep sky object.

Other choices represent different galaxies: the Whirlpool Galaxy, Triangulum Galaxy, and M87, each of which plays a significant role in astronomical studies, but none are as close to the Milky Way as Andromeda, making the correct identification of the Andromeda Galaxy significant in the context of nearby spiral galaxies.