The Great Wall (also called Coma Wall), sometimes specifically referred to as the CfA2 Great Wall, is an immense

galaxy filament In cosmology, galaxy filaments are the largest known structures in the universe, consisting of walls of galactic superclusters. These massive, thread-like formations can commonly reach 50 to 80 megaparsecs ()—with the largest found to date b ...

. It is one of the largest known superstructures in the

observable universe The observable universe is a Ball (mathematics), spherical region of the universe consisting of all matter that can be observation, observed from Earth; the electromagnetic radiation from these astronomical object, objects has had time to reach t ...

. This structure was discovered c. 1989 by a team of

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

s led by Margaret J. 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 ...

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 univ ...

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

Characteristics

According to Chown, "The filament is about 300 million lightyears wide, 15 million lightyears thick and it snakes for at least 500 million lightyears across the Universe."

Components

It was discovered in 1989 by

Margaret 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

based on

redshift survey In astronomy, a redshift survey is a astronomical surveys, survey of a section of the sky to measure the redshift of astronomical objects: usually galaxies, but sometimes other objects such as galaxy clusters or quasars. Using Hubble's law, the ...

data from the

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

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

galaxy A galaxy is a Physical system, system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, and dark matter bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', ...

where Earth is located. The gas and dust from the Milky Way (known as the

Zone of Avoidance The Zone of Avoidance (ZOA, ZoA), or Zone of Galactic Obscuration (ZGO), is the area of the sky that is obscured by the Milky Way. The Zone of Avoidance was originally called the Zone of Few Nebulae in an 1878 paper by English astronomer Richard ...

) 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 Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...

of the evolution of the universe, such structures as the Great Wall form along and follow web-like strings of

dark matter In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...

. It is thought that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts

baryon In particle physics, a baryon is a type of composite particle, composite subatomic particle that contains an odd number of valence quarks, conventionally three. proton, Protons and neutron, neutrons are examples of baryons; because baryons are ...

ic 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

Characteristics

Components

See also

References

External links