Local Void
Encyclopedia
The Local Void is a vast, empty region
of space
, devoid of matter
, located within the Virgo Supercluster
and lying adjacent to our own Milky Way galaxy. Discovered by Brent Tully of the American Astronomical Society
in Honolulu, Hawaii
, the Local Void is millions of light years in length, the exact extent of which is unknown. The void is divided into three separate sectors, which are separated by bridges of 'wispy filament
s'. The Local Void has significantly fewer galaxies than predicted by the standard theory of cosmic evolution.
to "clump together", herding galaxies into clusters
and chains, which are separated by regions mostly devoid of galaxies.
Astronomer
s have previously noticed that the Milky Way sits in a large, flat array of galaxies called the 'Local Sheet
', which bounds the Local Void.
The Local Void extends approximately 60 megaparsecs, beginning at the edge of the Local Group
. It is believed that the distance from Earth
to the center of the Local Void must be at least 23 Mp.
The size of the Void was calculated due to a lonely dwarf galaxy
located inside it. The bigger and emptier the void, the weaker its gravity, and the faster the dwarf should be fleeing the void towards concentrations of matter. Dark energy
has been suggested as an alternate explanation for the speedy expulsion of the dwarf galaxy.
An earlier "Hubble Bubble
" model, based on measured velocities of Type 1a supernovae, proposed a relative void centered on the Milky Way. Recent analysis of that data, however, suggested that interstellar dust had resulted in misleading measurements.
Void (astronomy)
In astronomy, voids are the empty spaces between filaments, the largest-scale structures in the Universe, that contain very few, or no, galaxies. They were first discovered in 1978 during a pioneering study by Stephen Gregory and Laird A. Thompson at the Kitt Peak National Observatory...
of space
Interstellar medium
In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...
, devoid of matter
Matter
Matter is a general term for the substance of which all physical objects consist. Typically, matter includes atoms and other particles which have mass. A common way of defining matter is as anything that has mass and occupies volume...
, located within the Virgo Supercluster
Virgo Supercluster
The Virgo Supercluster or Local Supercluster is the irregular supercluster that contains the Virgo Cluster in addition to the Local Group, which in turn contains the Milky Way and Andromeda galaxies. At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs...
and lying adjacent to our own Milky Way galaxy. Discovered by Brent Tully of the American Astronomical Society
American Astronomical Society
The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...
in Honolulu, Hawaii
Honolulu, Hawaii
Honolulu is the capital and the most populous city of the U.S. state of Hawaii. Honolulu is the southernmost major U.S. city. Although the name "Honolulu" refers to the urban area on the southeastern shore of the island of Oahu, the city and county government are consolidated as the City and...
, the Local Void is millions of light years in length, the exact extent of which is unknown. The void is divided into three separate sectors, which are separated by bridges of 'wispy filament
Galaxy filament
In physical cosmology, galaxy filaments, also called supercluster complexes or great walls, are, so far, the largest known cosmic structures in the universe. They are massive, thread-like structures with a typical length of 50 to 80 megaparsecs h-1 that form the boundaries between large voids in...
s'. The Local Void has significantly fewer galaxies than predicted by the standard theory of cosmic evolution.
Location and dimensions
Voids are the result of the way gravity causes matter in the universeUniverse
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
to "clump together", herding galaxies into clusters
Galaxy groups and clusters
Galaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation. They form the densest part of the large scale structure of the universe...
and chains, which are separated by regions mostly devoid of galaxies.
Astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
s have previously noticed that the Milky Way sits in a large, flat array of galaxies called the 'Local Sheet
Local Sheet
The Local Sheet in astronomy is a nearby region of the observable universe where the Milky Way, the members of the Local Group and other galaxies share a similar peculiar velocity. This region lies within a radius of about 7 Mpc, and galaxies beyond that distance show markedly different...
', which bounds the Local Void.
The Local Void extends approximately 60 megaparsecs, beginning at the edge of the Local Group
Local Group
The Local Group is the group of galaxies that includes Earth's galaxy, the Milky Way. The group comprises more than 30 galaxies , with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy...
. It is believed that the distance from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
to the center of the Local Void must be at least 23 Mp.
The size of the Void was calculated due to a lonely dwarf galaxy
Dwarf galaxy
A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Way's 200-400 billion stars...
located inside it. The bigger and emptier the void, the weaker its gravity, and the faster the dwarf should be fleeing the void towards concentrations of matter. Dark energy
Dark energy
In physical cosmology, astronomy and celestial mechanics, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe. Dark energy is the most accepted theory to explain recent observations that the universe appears to be expanding...
has been suggested as an alternate explanation for the speedy expulsion of the dwarf galaxy.
An earlier "Hubble Bubble
Hubble Bubble (astronomy)
In astronomy, a Hubble Bubble would be "a departure of the local value of the Hubble constant from its globally averaged value," or "a local monopole in the peculiar velocity field, perhaps caused by a local void in the mass density."The Hubble Constant, named for astronomer Edwin Hubble, whose...
" model, based on measured velocities of Type 1a supernovae, proposed a relative void centered on the Milky Way. Recent analysis of that data, however, suggested that interstellar dust had resulted in misleading measurements.