When Worlds Collide - NGC 520 (Arp 157)

Some 300 million years ago, 100 million light years away in the Pisces Constellation, two disc galaxies began the slow process of colliding. Scientists believe that these galaxies will eventually settle into elliptical form.

NGC 520's unusual shape also landed it in Halton Arp's Atlas of Peculiar Galaxies as Arp 157. In the image we see that while many parts of the two galaxies have merges, their cores have yet to come together. In the meantime, the collision is causing extreme star formation to occur—a circumstance that will likely abate once they form a single, elliptical galaxy.