M31 - Andromeda Galaxy

The Andromeda Galaxy is the nearest large galaxy to the Milky Way and is visible to the naked eye from Earth.

The Andromeda Galaxy, also known as Messier 31 (M31), is a spiral galaxy approximately 2.5 million light-years from Earth. It is the nearest large galaxy to the Milky Way and is one of the few visible to the naked eye from Earth.

Despite its vast distance, Andromeda appears as a faint smudge in the night sky, spanning about six times the diameter of the full moon when photographed with long exposures. The galaxy contains approximately one trillion stars, at least twice the number estimated in the Milky Way.

Andromeda and the Milky Way are approaching each other at about 68 miles (109 kilometers) per second, and are expected to collide in about 4.5 billion years. This collision will gradually pull both galaxies apart and then together again, eventually merging into a single giant elliptical galaxy.