The Great Wall (also called Coma Wall), sometimes specifically referred to as the CfA2 Great Wall, is an immense galaxy filament. It is one of the largest known superstructures in the observable universe. This structure was discovered c. 1989 by a team of American astronomers led by

Margaret J. Geller Margaret J. Geller (born December 8, 1947) is an American astrophysicist at the Center for Astrophysics Harvard & Smithsonian. Her work has included pioneering maps of the nearby universe, studies of the relationship between galaxies and their ...

and John Huchra while analyzing data gathered by the second

CfA Redshift Survey The Center for Astrophysics (CfA) Redshift Survey was the first attempt to map the large-scale structure of the universe. The first survey began in 1977 with the objective of calculating the velocities of the brighter galaxies in the nearby unive ...

of the Center for Astrophysics Harvard & Smithsonian (CfA).

Characteristics

The term "Great" has been added to distinguish it as an even larger type compared to standard galaxy walls. Great walls are so rare that only five or possibly six (if the disputed Hercules–Corona Borealis Great Wall is counted) of them have been discovered to date. The CfA2 Great Wall has the maximum dimensions of either 500 million or 750 million light years depending on the figure and the reference used. It is 200 million light years in width and about 16 million light years in thickness. Its nearest point is about 300 million light years from Earth, while its farthest point is 550 million light years away. It consists of three massive galaxy superclusters: Hercules,

Coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...

, and

Leo Leo or Léo may refer to: Acronyms * Law enforcement officer * Law enforcement organisation * ''Louisville Eccentric Observer'', a free weekly newspaper in Louisville, Kentucky * Michigan Department of Labor and Economic Opportunity Arts an ...

. The CfA2 Great Wall includes the

Coma Filament The Coma Filament is a galaxy filament. The filament contains the Coma Supercluster of galaxies and forms a part of the CfA2 Great Wall. See also * Abell catalogue * Large-scale structure of the universe * Supercluster A supercluster is a large ...

Components

It was discovered in 1989 by Margaret Geller and

John Huchra John Peter Huchra ( ; December 23, 1948 – October 8, 2010) was an American astronomer and professor. He was the Vice Provost for Research Policy at Harvard University and a Professor of Astronomy at the Center for Astrophysics Harvard & Sm ...

based on redshift survey data from the

. It is not known how much farther the wall extends due to the light absorption in the plane of the Milky Way

galaxy A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

in which Earth is located. The gas and dust from the Milky Way (known as the Zone of Avoidance) obscure the view of astronomers and have so far made it impossible to determine if the wall ends or continues on further than they can currently observe. In the

standard model The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions - excluding gravity) in the universe and classifying a ...

of the evolution of the universe, 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 baryonic matter, and it is this "normal" matter that astronomers see forming long, thin walls of super-galactic clusters.

References

External links

Map of CfA2 Great Wall

The CfA Redshift Survey
{{DEFAULTSORT:Cfa2 Great Wall Astronomical objects discovered in 1989 Galaxy filaments Large-scale structure of the cosmos