How big is the Andromeda Galaxy?

The Andromeda Galaxy, spanning approximately 220,000 light years, is the largest galaxy in our Local Group, which is also home to the Triangulum Galaxy and other minor galaxies. The Andromeda Galaxy's mass is estimated to be around 1.76 times that of the Milky Way Galaxy (~0.8-1.5 × 10 12 solar masses vs the Milky Way's 8.5 × 10 11 solar masses). read more

By Jake Parks | February 15, 2018 10:25 am This image of the Andromeda galaxy, captured by NASA’s Galaxy Evolution Explorer, shows the ultraviolet side of our familiar galactic neighbor. read more

Both the Milky Way and the Andromeda galaxy (M31) are giant spiral galaxies in our local universe. And in about 4 billion years, the Milky Way and Andromeda will collide in a gravitational sumo match that will ultimately bind them forever. read more