For years, astronomers have observed the strange motion of Andromeda, the Milky Way’s closest large galactic neighbor. While most galaxies in the universe are receding due to the expansion of space, ...

For more than a century, astronomers have watched in astonishment as the Andromeda galaxy ignored the grand flow of cosmic expansion and hurtled straight toward the Milky Way. While almost every other ...

Astronomers used RR Lyrae stars to trace the early Milky Way, revealing a rapid formation of its halo and disk, with chemical patterns similar to Andromeda.

Astronomers have long known that the Andromeda galaxy, aka Messier 31, a swirling city-state of a trillion stars — plus all the accouterments of gas, dust, dark matter and black holes — is rumbling ...

Four billion years from now, the Milky Way galaxy as we know it will cease to exist. Our Milky Way is bound for a head-on collision with the similar-sized Andromeda galaxy, researchers announced today ...