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The Laniakea Supercluster or Laniakea for short (; Hawaiian for "open skies" or "immense heaven") is the large-scale structure centered around the Great Attractor that is home to the Milky Way and approximately 100,000 other nearby galaxies.

It was originally defined in September 2014 as a galaxy supercluster, when a group of astronomers, including R. Brent Tully of the University of Hawaiʻi at Mānoa, Hélène Courtois of the University of Lyon, Yehuda Hoffman of the Hebrew University of Jerusalem, and Daniel Pomarède of CEA Université Paris-Saclay published a new way of defining superclusters according to the relative velocities of galaxies as basins of attraction. The new definition of the Local Supercluster subsumes the then prior defined Virgo and Hydra-Centaurus Supercluster as appendages, the former being the historical local supercluster. Follow-up studies suggest that the Laniakea is not gravitationally bound. In addition, some papers favored the traditional definition of superclusters as high-density regions of the cosmic web; basins of attraction including Laniakea were therefore proposed to be called "supercluster cocoons" (or "cocoons" for short), containing smaller traditional superclusters, which evolve inside their parent cocoon. The Laniakea is the inner part of the local superstructure, also known as Pisces–Cetus Supercluster Complex. Latest observations of basins of attraction suggested a basin of attraction around Ophiuchus Cluster may be associated with Laniakea, and also have found both are moving toward the Shapley Concentration and may thus be part of this greater structure.

The Laniakea supercluster encompasses approximately 100,000 galaxies stretched out roughly 120 Mpc (400 million ly). Virgo Supercluster, the part in which the Virgo Cluster and the Local Group, including the Milky Way, reside.

Southern Supercluster, including Fornax Cluster (S373), Dorado and Eridanus clouds. Ophiuchus Supercluster,, including the Ophiuchus Cluster, the site of Ophiuchus Supercluster eruption Norma Wall, including the Norma Supercluster, which contains the Norma Cluster

The most massive galaxy clusters of the Laniakea are Virgo, Hydra, Centaurus, Abell 3565, Abell 3656, Abell 2870, Abell 3581, Abell 3574, Abell 3521, Fornax, Eridanus, Ophiuchus, and Norma. This gravitational focal point, in the case of Laniakea, is called the Great Attractor, and influences the motions of the Local Group of galaxies, where the Milky Way galaxy resides, and all others throughout the supercluster. The same study that confirmed the Laniakea proposed to define a supercluster as basins of attraction, rather than high-density regions such as the Virgo Supercluster. Follow-up studies favored the traditional definition of superclusters as high-density regions, with referred to basins of attraction such as Laniakea as "supercluster cocoons" ("cocoons") or "watershed superclusters" ("watersheds"). Because there is no community consensus on an agreed defintion of the term supercluster, other studies avoid calling any structure a supercluster, including Laniakea and Shapley, which were referred as simply basins of attraction. Although confirmation of the existence of the Laniakea supercluster emerged in 2014, early studies in the 1980s already suggested that several of the then-known superclusters might be connected. More recent observations using Cosmicflows-4 catalog have shown that a basin of attraction centered on the Ophiuchus Cluster might be associated with Laniakea, forming a "probabilistic Basin of Attraction" ("p-BoA").

The neighboring superclusters to the Laniakea are the Shapley, Hercules, Coma, and Perseus–Pisces Superclusters. Because the Laniakea, Apus, and Coma superclusters are moving toward the Shapley Supercluster, they may be sub-basins part of this larger basin of attraction. Laniakea is also a constituent part of a much larger local superstructure that has also been proposed by R. Brent Tully, referred to as the Pisces–Cetus Supercluster Complex, a galaxy filament.

Vimeo, "Laniakea Supercluster", Daniel Pomarède, 4 September 2014—video representation of the findings of the discovery paper YouTube, "Laniakea: Our Home Supercluster", Nature Video, 3 September 2014—Redrawing the boundaries of the cosmic map, they redefine our home supercluster and name it Laniakea.

Quick Facts

• The new definition of the Local Supercluster subsumes the then prior defined Virgo and Hydra-Centaurus Supercluster as appendages, the former being the historical local supercluster.
• YouTube, "Laniakea: Our Home Supercluster", Nature Video, 3 September 2014—Redrawing the boundaries of the cosmic map, they redefine our home supercluster and name it Laniakea.
• The Laniakea is the inner part of the local superstructure, also known as Pisces–Cetus Supercluster Complex.
• The same study that confirmed the Laniakea proposed to define a supercluster as basins of attraction, rather than high-density regions such as the Virgo Supercluster.
• It was originally defined in September 2014 as a galaxy supercluster, when a group of astronomers, including R.

Source material: Wikipedia - "Laniakea Supercluster". Adapted and summarized for DiscoverScroll. Original contributors are credited through the linked Wikipedia article. Read original on Wikipedia. CC BY-SA 4.0. Changes were made from the original.