By tracking galaxies like water drops in a river system, an international team of astronomers has mapped and named the enormous network of galaxies, in which the Milky Way resides. The structure—100 times more massive than previously believed—has been christened Laniakea, Hawaiian for “immeasurable heaven.”

Galaxies like our Milky Way clump together in clusters, which aggregate in even larger networks known as superclusters. Previously, scientists placed our Milky Way in the Virgo supercluster, a concentration of galaxies weighing about a million billion Suns. But the new study, published in Nature, puts the Virgo supercluster on the fringes of Laniakea, which stretches over half a billion light-years from end to end.

To map the universe at such grand scales, researchers led by University of Hawaii astronomer R. Brent Tully tracked over 8,000 galaxies, revealing groups of galaxies gravitationally attracted toward large central regions of high mass. They found that each region had clear boundaries—the outermost galaxies draining toward each region’s center—similar to those that separate Earth’s river systems, “where you can have water flowing in two different directions,” says Tully. These new structures, Laniakea chief among them, give astronomers their first clear-cut definition for superclusters.

Laniakea’s 100,000 galaxies drain into the Great Attractor, a massive region containing about half of the supercluster’s mass; however, the universe’s expansion assures that they will not all lump together, says Tully, clarifying that Laniakea’s galaxies are moving outward slower than they otherwise would.

While our Milky Way may be a drop in Laniakea, Laniakea may be a drop in an even bigger river. In fact, Tully says, it is moving toward an even bigger entity at a velocity of 600 kilometers per second, which means “there’s something going on at a scale even larger than Laniakea.”