A vast, flat sheet of dark matter may solve the long-standing mystery of why our neighboring galaxy Andromeda is speeding ...

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 ...

You might think galaxies can’t ever find each other in our runaway cosmos, but it turns out gravity can sometimes overcome ...

This idea is called the big bang model—which is an unfortunate name because it brings to mind a cosmos expanding like an ...

For years, astronomers have observed the strange motion of Andromeda, the Milky Way’s closest large galactic neighbor. While ...

Because it takes time for light to travel large distances, the quintet's collision in the far-off reaches of space happened when the universe was just 800 million years old. Such a five-way merger ...