Great Attractor

Region of gravitational attraction in the local universe Hubble Space Telescope image showing part of the Norma Cluster, including the galaxy ESO 137-002 The Great Attractor is a region of enhanced gravitational attraction in the local universe. It lies in the general direction of the Norma Cluster and the Hydra–Centaurus Supercluster, approximately 150–250 million light-years from the Milky Way. Its presence was inferred from the peculiar motions of galaxies, which deviate from the motion expected solely from the expansion of the universe. The term does not refer to a single galaxy, galaxy cluster, or compact astronomical object. Instead, it describes a broad concentration of matter and an associated minimum in the local gravitational-potential and velocity fields. Early models attributed a mass of approximately 1016 solar masses (M☉) to the region. Later observations indicated that the motion of nearby galaxies cannot be explained by the Great Attractor region alone and that more distant structures, particularly the Shapley Supercluster, also contribute substantially. The region is difficult to observe at visible wavelengths because it lies behind the galactic plane of the