Editing Observable universe (section)

=== Cosmography of Earth's cosmic neighborhood ===
At the centre of the [[Hydra–Centaurus Supercluster]], a gravitational anomaly called the [[Great Attractor]] affects the motion of galaxies over a region hundreds of millions of light-years across. These galaxies are all [[redshift]]ed, in accordance with [[Hubble's law]]. This indicates that they are receding from us and from each other, but the variations in their redshift are sufficient to reveal the existence of a concentration of mass equivalent to tens of thousands of galaxies.

The Great Attractor, discovered in 1986, lies at a distance of between 150 million and 250 million light-years in the direction of the [[Hydra (constellation)|Hydra]] and [[Centaurus]] [[constellation]]s. In its vicinity there is a preponderance of large old galaxies, many of which are colliding with their neighbours, or radiating large amounts of radio waves.

In 1987, [[astronomer]] [[R. Brent Tully]] of the [[University of Hawaii]]'s Institute of Astronomy identified what he called the [[Pisces–Cetus Supercluster Complex]], a structure one billion [[light-year]]s long and 150 million light-years across in which, he claimed, the Local Supercluster is embedded.<ref>{{Cite news|url=https://www.nytimes.com/1987/11/10/science/massive-clusters-of-galaxies-defy-concepts-of-the-universe.html|title=Massive Clusters of Galaxies Defy Concepts of the Universe|first=John Noble|last=Wilford|newspaper=The New York Times|date=November 10, 1987}}</ref>