Reblogged from memoirs on a rainy day:

New astronomical simulations suggest that the enormous swirls of stars surrounding the NGC 5907 galaxy, located 50 million light-years away, in the constellation Draco, were formed when two equal-sized galaxies collided 8 or 9 billion years ago. The research was published in the journal Astronomy & Astrophysics by Wang et al. Read more @ SciTechDaily