Our "Cannibalistic" Neighbor Andromeda Could Eat Milky Way, Scientists Say

"Knowing what kind of a monster our galaxy is up against is useful in finding out the Milky Way's ultimate fate."

The stars orbiting Andromeda gave the researchers clues about the ancient collisions with other galaxies. The team studied dense groups of stars, known as globular clusters, to reveal how many years ago galaxies were consumed by Andromeda.

"By tracing the faint remains of these smaller galaxies with embedded star clusters, we've been able to recreate the way Andromeda drew them in and ultimately enveloped them at the different times," Dr. Mackey said.

Understanding our own galaxy

Knowing more about Andromeda's behavior can teach us more about our own galaxy — the Milky Way has also eaten other galaxies throughout the history of the universe.

But what will happen when the collision takes place?

"I think it's unlikely the Earth will be physically destroyed by the collision with Andromeda," Mackey told CNN. "It's not out of the question, but in general the stars in galaxies are spaced sufficiently sparsely that direct collisions between stars are rare."

"However, it's possible that the Sun could be thrown out of the merged Andromeda and Milky Way system by the collision, into intergalactic space, and/or a nearby close passage with another star could perturb the Earth's orbit such that the Earth can no longer support life," he explained.

What the scientists are most interested in, however, is figuring out new mysteries that have arisen from their investigations. For example, two of the galaxy consumptions come from completely different directions. The stellar investigation continues.