What is a supercluster?

A collection of multiple galaxy clusters and groups bound together in a larger structure, spanning hundreds of millions of light-years A single very large galaxy that contains more than a trillion stars A cluster of quasars found in the early universe The zone immediately surrounding a large galaxy cluster where smaller groups orbit

What is the Laniakea Supercluster?

The supercluster that contains our galaxy, defined in 2014 as spanning 520 million light-years with 100,000 galaxies and a mass of 100 quadrillion solar masses The most distant supercluster known, located near the edge of the observable universe A supercluster discovered in 1929 by Edwin Hubble in the constellation Laniakea The supercluster that will collide with the Virgo Cluster in 5 billion years

What does the cosmic web look like?

A perfectly uniform distribution of galaxies with no structure at any scale A network of filaments (where galaxy clusters are concentrated), sheets (2D walls of galaxies), and vast empty voids between them Concentric shells of galaxies expanding outward from the site of the Big Bang A single massive ring of galaxies surrounding an empty central region

What are cosmic voids?

Regions of space where dark energy is stronger than average, pushing galaxies apart faster The central regions of galaxy clusters where stars are most densely packed Vast regions of space nearly empty of galaxies, typically 100-400 million light-years across, surrounded by galaxy filaments and sheets Regions where the cosmic microwave background is absent, created by galaxy absorption

What is the Sloan Great Wall?

A physical wall built around the Sloan galaxy cluster to block cosmic rays A vast sheet of galaxies about 1.37 billion light-years long, one of the largest known structures in the universe The name given to the observable universe boundary discovered by the Sloan survey A string of quasars found along the edge of the Sloan Digital Sky Survey boundary

On what scale does the universe become homogeneous and isotropic (looking the same in all directions)?

On scales larger than about 300 million light-years, the distribution of matter becomes smooth and uniform in all directions The universe is only homogeneous at the scale of individual galaxies The universe is never homogeneous — structure exists at every scale including the very largest The universe is homogeneous on scales larger than 1 light-year because all stars are similar

What is the Hercules-Corona Borealis Great Wall?

A famous telescope array located between the Hercules and Corona Borealis constellations A supercluster that is part of the Laniakea Supercluster on the side facing the constellations Hercules and Corona Borealis A proposed enormous structure about 10 billion light-years long, potentially the largest structure ever identified in the universe The boundary of the observable universe as seen in the direction of those constellations

What is the Great Attractor?

A large black hole at the center of the Virgo Cluster that is pulling all nearby galaxies inward A gravitational anomaly at the center of the Laniakea Supercluster toward which the Milky Way and hundreds of thousands of other galaxies are flowing The gravitational field of the Andromeda Galaxy attracting the Milky Way Dark energy concentrated in a specific region that attracts galaxies toward it

What does the word Laniakea mean in Hawaiian, and why was it chosen as the name?

Galaxy home — chosen to reflect that it is our home supercluster Land of many islands — inspired by the thousands of galaxies it contains Immeasurable heaven — chosen to reflect the vast and almost incomprehensible scale of our home supercluster Great attractor — named after the gravitational center it flows around

Why do galaxies tend to be found in filaments and sheets rather than randomly distributed through space?

The rotation of the universe pushes galaxies toward its equator forming a flat disk structure Gravity amplified tiny density fluctuations from the early universe, causing matter to collapse preferentially along planes and filaments rather than uniformly in 3D Dark energy repels galaxies away from the center of the universe, pushing them to the edges Galaxies are randomly distributed and only appear to be in filaments due to selection effects in our surveys