An unseen mass is dragging the Milky Way through space at 1.3 million mph. But when astronomers finally peered through the cosmic dust, they found the Great Attractor wasn't the true culprit.
When researchers first mapped this cosmic drift in the 1970s, they named the gravitational anomaly pulling the local universe the Great Attractor. For decades, it remained a mystery because it sits in a region of the sky called the Zone of Avoidance. The anomaly lies directly behind the dense central plane of the Milky Way, where gas, dust, and stars block visible light and act as a blindfold.
Once astronomers began mapping the sky using X-ray and radio telescopes—which can peer through the galactic dust—they found the initial suspect. At the heart of the Great Attractor lies the Norma Cluster (Abell 3627), a dense concentration of thousands of old, colliding galaxies located about 150 million light-years away. It sits near the center of the Laniakea Supercluster, the immense web of galaxies that contains the Milky Way.
However, the Norma Cluster alone does not have nearly enough mass to account for the immense gravitational pull on the local universe. It turns out the Great Attractor is just a localized accumulation of matter being pulled by something even larger.
Farther out, roughly 650 million light-years away and directly behind the Great Attractor, lies the Shapley Supercluster. This behemoth contains more than 8,000 galaxies and represents the most massive concentration of matter within a billion light-years of Earth. The Shapley Supercluster is the true cosmic anchor. Its gravity is pulling the Great Attractor toward it, and the Great Attractor is dragging the Milky Way along for the ride.