A Family of worlds Though the Milky Way feels vast to us, it is n't alone in the macrocosm. Like people gathering in townlets, worlds gather into groups, bound together by graveness. Our home cluster is called the Original Group — a small family of worlds drifting together through the cosmic void. The Original Group spans 10 million light- times across and contains further than 80 worlds, though utmost are bitsy dwarf systems. At its heart are three titans The Milky Way( our home). Andromeda( M31), the largest and brightest. The Triangulum Galaxy( M33), lower but still a graceful curl. Together, these worlds shape the fortune of our corner of the macrocosm. The Dominance of titans The Milky Way and Andromeda rule the Original Group, like binary monarchs sluggishly moving toward one another. Andromeda( M31) is about 2.5 million light- times down. It holds roughly a trillion stars — twice the Milky Way’s mass. The Milky Way, slightly lower, still rivals Andromeda