Henrietta Swan Leavitt they became an important part of the evidence that "spiral nebulae" are independent galaxies located far outside of our own Milky Way. Thus, Leavitt's discovery would forever change our picture of the universe, as it prompted Harlow Shapley to move our Sun from the center of the galaxy in the "Great Debate" and Edwin Hubble to move our galaxy from the center of the universe. Leavitt's discovery of a way to accurately measure distances on an inter-galactic scale, paved the way for modern astronomy's understanding of the structure and scale of the universe. The accomplishments of Edwin Hubble, the American
Atlas of Peculiar Galaxies implies that the galaxies are separating apart, most of these galaxies are merging. Many of the objects have very pronounced tidal tails and bridges that have formed as a consequence of the interaction. Most objects are in the early stages of the merging process, where the galaxies still appear to have distinct nuclei and distinct (albeit distorted) disks. Among the most notable galaxies in this category are the Antennae Galaxies (NGC 4038 and NGC 4039, Arp 244) and the Mice Galaxies (NGC 4676, Arp 242). However, not all of these objects are interacting galaxies. A few of these galaxies are