259x259px, A map of the Boötes Void The Boötes Void ( ) (colloquially referred to as the Great Nothing) is a roughly

spherical A sphere (from Ancient Greek, Greek , ) is a surface (mathematics), surface analogous to the circle, a curve. In solid geometry, a sphere is the Locus (mathematics), set of points that are all at the same distance from a given point in three ...

region of

space Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless ...

in the vicinity of the constellation

Boötes Boötes ( ) is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from , which comes from 'herder, herdsman' or 'plowman' (literally, 'o ...

. It contains just 60

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and 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 Sys ...

, a figure significantly lower than the approximately 2,000 galaxies expected for an area of comparable size. With a radius of 62

megaparsecs The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (AU), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

(nearly 330 million

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s), it is one of the largest

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, ...

in the visible universe, and is often referred to as a "supervoid". It was discovered in 1981 by astronomer Robert Kirshner as part of a survey of galactic

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 increase in frequency and e ...

. Its centre is located 700 million light-years from Earth, at

right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the equinox (celestial coordinates), March equinox to the (hour circle of the) point in questio ...

and

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or ...

. 260x260px, A map of galaxy voids The

Hercules Superclusters The Hercules Superclusters (SCl 160) refers to a set of two nearby superclusters of galaxies. Relative to other local superclusters, Hercules is considered particularly large, being approximately 330 Mly in diameter. The Northern Local Supervoid ...

are part of the near edge of the void.

Formation

The existence of the Boötes Void does not appear to conflict with the Lambda-cold dark matter (ΛCDM) model of cosmological evolution. It is hypothesized that the Boötes Void formed through the coalescence of smaller voids. This process may explain the presence of a limited number of galaxies within a roughly cylindrical region extending through the center of the void.

References

Sources

* * {{DEFAULTSORT:Bootes Void category:voids (astronomy) category:Boötes

Formation

See also

References

Sources