This is a list of the largest cosmic structures so far discovered. The unit of measurement used is the

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

(distance traveled by light in one Julian year; approximately 9.46 trillion

kilometres The kilometre ( SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for ). It is now the measurement unit used for ...

). This list includes

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 turn ...

galaxy filaments In cosmology, 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 Qu ...

and

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

(LQGs). The list characterizes each structure based on its longest dimension. Note that this list refers only to coupling of matter with defined limits, and not the coupling of matter in general (as per example the

cosmic microwave background In Big Bang cosmology the cosmic microwave background (CMB, CMBR) is electromagnetic radiation that is a remnant from an early stage of the universe, also known as "relic radiation". The CMB is faint cosmic background radiation filling all spac ...

, which fills the entire universe). All structures in this list are defined as to whether their presiding limits have been identified. There are some speculations about this list: *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 ...

, or the part of the sky occupied by 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 ...

, blocks out light to several structures, making their limits imprecisely identified. *Some structures are far too distant to be seen even with the most powerful telescopes. Some factors are included to explain the structure (like

gravitational lensing A gravitational lens is a distribution of matter (such as a galaxy cluster, cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This ...

and

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...

data). *Some structures have no defined limits, or endpoints. All structures are believed to be part of the

cosmic web The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time, because the electromagnetic radiation from these obj ...

, which is a conclusive idea. Most structures are overlapped by nearby galaxies, creating a problem of how to carefully define the structure's limit. __TOC__

List of largest structures

List of largest voids

Void 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 are immense spaces between galaxy filaments and other large-scale structures. Technically they are not structures. They are vast spaces which contain very few or no galaxies. They are theorized to be caused by quantum fluctuations during the early formation of the universe. A list of the largest voids so far discovered is below. Each is ranked according to its longest dimension.

References

{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System * Structures, largest Largest structures cosmic structures

List of largest structures

List of largest voids

See also

References