:''This article is about the CfA2 Great Wall. For the Sloan Great Wall, see
Sloan Great Wall''. For other uses see
Great Wall (disambiguation).
The 'Great Wall', sometimes more specifically referred to as the 'CfA2 Great Wall', is the second largest known
super-structure in the
Universe. It is a
filament of
galaxies approximately 200 million
light-years away and has dimensions which measure over 500 million light-years long, 300 million light-years wide and "only" 15 million light-years thick. It was discovered in
1989 by
Margaret Geller and
John Huchra based on
redshift survey data from the
CfA Redshift Survey[1].
It is not known how much further the wall extends due to the plane of the
Milky Way galaxy in which
Earth is located. The
gas and dust from the Milky Way (known as the
zone of avoidance) obscures astronomers' view and have so far made it impossible to determine if the wall ends or continues on further than they can currently observe.
It is hypothesized that such structures as the Great Wall form along and follow web-like strings of
dark matter. It is thought that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts normal matter, and it is this normal matter that astronomers see forming long thin walls of Super-Galactic clusters.
The largest known cosmic structure is the
Sloan Great Wall, discovered in 2003 in data from the
Sloan Digital Sky Survey; it is about a billion light-years away, and about 1.5 billion light-years in length.
References
1. M. J. Geller & J. P. Huchra, ''Science'' '246', 897 (1989).
See also
★
Sloan Great Wall
★
WMAP Cold Spot
★
Large-scale structure of the cosmos