"Our Milky Way galaxy snatched up many of its most ancient stars from smaller galaxies that shredded each other in violent collisions, a new study suggests.
Using new supercomputer simulations, researchers found that some ancient Milky Way stars did not form natively with the rest of the galaxy about 10 billion years ago. Instead, they are actually the leftovers from other galaxies that collided about 5 billion years ago."