Andromeda is into Cannibalism

We generally don't consider cannibalism a good thing. I mean, eating another human isn't so great for that other human! But when it comes to astronomy, cannibalism is a pretty cool thing! Take the Andromeda galaxy, for example. New data provides evidence showing the Andromeda Galaxy ate up several smaller dwarf galaxies at various points in its lifetime.

Andromeda Galaxy - Picture taken using amateur refractor telescope. Courtesy of Kanwar Singh

The Andromeda galaxy is one of two big galaxies in the area near us. The other big galaxy? Us...the Milky Way galaxy. Galaxy mergers are a way of life out in the Universe. If both galaxies are near the same size, neither really wins the battle and they could merge into one galaxy. Smaller galaxies going to battle against larger galaxies always lose. The smaller galaxies are swallowed and become part of the larger galaxy due to the larger gravitational forces. Don't worry though, the odds of any collision between two individual stars during a galaxy merger are extremely small. Space is so empty that mergers in which billions of stars from one galaxy are merging with another result in no stellar collisions. Okay, the odds are not zero, but they are so small that they are practically zero!

Andromeda Galaxy Swallowed Many Dwarf Galaxies During Its Lifetime