cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

, galaxy filaments (subtypes: supercluster complexes, galaxy walls, and galaxy sheets) Boris V. Komberg, Andrey V. Kravtsov, Vladimir N. Lukash; "The search and investigation of the Large Groups of Quasars" ; ;R.G. Clowes; "Large Quasar Groups - A Short Review"; ''The New Era of Wide Field Astronomy'', ASP Conference Series, vol. 232.; 2001; Astronomical Society of the Pacific; ; are the largest known structures in the

universe The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the univers ...

, consisting of walls of gravitationally bound galaxy

supercluster A supercluster is a large group of smaller galaxy clusters or galaxy groups; they are among the largest known structures in the universe. The Milky Way is part of the Local Group galaxy group (which contains more than 54 galaxies), which in t ...

s. These massive, thread-like formations can reach 80 megaparsecs ''h''⁻¹ (or of the order of 160 to 260 million

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distance, astronomical distances and is equivalent to about 9.46 Orders of magnitude (numbers)#1012, trillion kilometers (), or 5.88 ...

s) and form the boundaries between large

voids Void may refer to: Science, engineering, and technology * Void (astronomy), the spaces between galaxy filaments that contain no galaxies * Void (composites), a pore that remains unoccupied in a composite material * Void, synonym for vacuum, a s ...

Formation

In the

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

of the evolution of the universe, galactic filaments form along and follow web-like strings of

dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ...

—also referred to as the galactic web or cosmic web. It is thought that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts

baryonic matter In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classifie ...

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

Discovery

Discovery of structures larger than superclusters began in the late-1980s. In 1987, astronomer R. Brent Tully of the

University of Hawaii A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...

's Institute of Astronomy identified what he called the Pisces–Cetus Supercluster Complex. In 1989, the

CfA2 Great Wall 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. 198 ...

was discovered, followed by the

Sloan Great Wall The Sloan Great Wall (SGW) is a cosmic structure formed by a giant wall of galaxies (a galaxy filament). Its discovery was announced from Princeton University on October 20, 2003, by J. Richard Gott III, Mario Jurić, and their colleagues, ba ...

in 2003. On January 11, 2013, researchers led by Roger Clowes of the

University of Central Lancashire , mottoeng = "From the Earth to the Sun" , established = as Institution for the Diffusion of Useful Knowledgere-established 1992 (University status granted) , type = Public , chancellor ...

announced the discovery of a

large quasar group A large quasar group (LQG) is a collection of quasars (a form of supermassive black hole active galactic nuclei) that form what are thought to constitute the largest astronomical structures in the observable universe. LQGs are thought to be precu ...

, the Huge-LQG, which dwarfs previously discovered galaxy filaments in size. In November 2013, using

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten millise ...

s as reference points, astronomers discovered the

Hercules–Corona Borealis Great Wall The Hercules–Corona Borealis Great Wall or simply the Great Wall is the largest known structure in the observable universe, measuring approximately 10 billion light-years in length (the observable universe is about 93 billion light-years in di ...

, an extremely huge filament measuring more than 10 billion light-years across.

Filaments

Filament subtype of filaments have roughly similar major and minor axes in cross-section, along the lengthwise axis. * A short filament, detected by identifying an alignment of star-forming galaxies, in the neighborhood of the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

and the Local Group was proposed by Adi Zitrin and

Noah Brosch Noah Brosch (born 1948) is an Israeli astronomer, astrophysicist and space researcher. Biography Noah Brosch was born in Bucharest (Romania) in 1948 and immigrated with his family to Israel in 1963. Brosch studied at Tel Aviv University (BSc ...

. The reality of this filament, and the identification of a similar but shorter filament, were the result of a study by McQuinn ''et al.'' (2014) based on distance measurements using the TRGB method.

Galaxy walls

The galaxy wall subtype of filaments have a significantly greater major axis than minor axis in cross-section, along the lengthwise axis. Large-scale structure of light distribution in the universe

Large-scale structure of light distribution in the universe

* A "Centaurus Great Wall" (or "Fornax Great Wall" or "Virgo Great Wall") has been proposed, which would include the Fornax Wall as a portion of it (visually created by 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 ...

) along with the

Centaurus Supercluster Centaurus is a bright constellation in the southern sky. One of the largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. ...

and the

Virgo Supercluster The Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of galaxies containing the Virgo Cluster and Local Group, which itself contains the Milky Way and Andromeda galaxies, as well as others. At least ...

also known as our Local Supercluster within which the Milky Way galaxy is located (implying this to be the Local Great Wall). * A wall was proposed to be the physical embodiment of the

Great Attractor The Great Attractor is a gravitational anomaly in intergalactic space and the apparent central gravitational point of the Laniakea Supercluster. The observed anomalies suggest a localized concentration of mass millions of times more massive than ...

, with the

Norma Cluster The Norma Cluster (ACO 3627 or Abell 3627) is a rich cluster of galaxies located near the center of the Great Attractor; it is about distant. Although it is both nearby and bright, it is difficult to observe because it is located in the Zone of ...

as part of it. It is sometimes referred to as the Great Attractor Wall or Norma Wall. This suggestion was superseded by the proposal of a supercluster, Laniakea, that would encompass the Great Attractor, Virgo Supercluster, Hydra-Centaurus Superclusters. * A wall was proposed in 2000 to lie at z=1.47 in the vicinity of radio galaxy B3 0003+387. * A wall was proposed in 2000 to lie at z=0.559 in the northern Hubble Deep Field (HDF North).

Map of nearest galaxy walls

Large Quasar Groups

Large quasar group A large quasar group (LQG) is a collection of quasars (a form of supermassive black hole active galactic nuclei) that form what are thought to constitute the largest astronomical structures in the observable universe. LQGs are thought to be precu ...

s (LQGs) are some of the largest structures known. They are theorized to be protohyperclusters/proto-supercluster-complexes/galaxy filament precursors.

Supercluster complex

Maps of large-scale distribution

File:Superclusters atlasoftheuniverse.gif, The universe within 1 billion light-years (307 Mpc) of Earth, showing local

s forming filaments and voids File:Nearsc.gif, Map of nearest walls, voids and superclusters File:2dfdtfe.gif, 2dF survey map, containing the SDSS Great Wall File:2MASS LSS chart-NEW Nasa.jpg, 2MASS XSC infrared sky map

References

External links

Pictures of the filamentary network

{{Portal bar, Stars, Spaceflight, Outer space, Solar System, Science Large-scale structure of the cosmos