The Andromeda galaxy, which researchers think will collide with the Milky Way in billions of years. One new study shows how our galaxy was shaped by a merger with a dwarf galaxy 10 billion years ago. (Credit: NASA JPL) Our galaxy, perhaps like many in the universe, is a bit of a Frankenstein's monster. A new study makes a compelling case that a central structure in the Milky Way is actually composed mostly of stars born in another galaxy, brought to us by a long-ago galactic smash-up. 10 billion years ago, our own galaxy collided with a smaller dwarf galaxy in a crash so intense that it ripped the smaller body apart and forever changed the structure of the Milky Way.
The Milky Way has a number of distinct structures: The central bulge, spiral arms, the disk and the halo. By looking at the age, movement and composition of stars, ...
