The Andromeda Galaxy (M31) is the closest galaxy to the Milky Way which is about 2.5 million light-years away. It is the largest spiral galaxy in the Local Group, a group of galaxies that also ...

Historically, the Andromeda Galaxy (M31) was a subject of extensive debate, initially considered a "nebulous smear" and later central to the "island universe" hypothesis proposing its status as an ...

Huge eruptions from the Milky Way’s supermassive black hole in the distant past may have sterilized much of the inner galaxy ...

The bold question-askers at What If examine what would happen if the Milky Way and Andromeda collided.