Some nearby galaxies, like Andromeda, were moving toward us rather than away, exactly what you'd expect from gravity between neighboring galaxies. Despite the substantial combined mass of the Milky Way, Andromeda, and dozens of smaller galaxies forming what's called the Local Group, these neighbours seemed oddly unaffected. They receded from us following the smooth Hubble-Lemaître expansion law as if our local gravitational pull didn't matter at all. The mass distribution just beyond the Local Group, it turns out, isn't spherical or random. Source : The Milky Way is embedded in a ‘large-scale sheet’ and this explains the motions of nearby galaxies