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Hydra–Centaurus Supercluster
The Hydra-Centaurus Supercluster (SCl 128), or the Hydra and Centaurus Superclusters, is a supercluster in two parts, the closest neighbour of Virgo Supercluster. Hydra-Centaurus The cluster includes four large galaxy clusters in the Centaurus part * Abell 3526 (Centaurus Cluster) * Abell 3565 * Abell 3574 * Abell 3581 and the proximate * Hydra Cluster (A1060) * Antlia Cluster (AS0636) Apart from the central clusters, which are 150 to 200 million light years away, several smaller clusters belong to the group. Within the proximity of this supercluster lies the Great Attractor, dominated by the Norma Cluster (Abell 3627). This massive cluster of galaxies exerts a large gravitational force, causing all matter within 50 Mpc to experience a bulk flow of 600 km/s toward the Norma Cluster Laniakea A 2014 announcement says that the Centaurus Supercluster (Hydra–Centaurus) is just a lobe in a greater supercluster, Laniakea, that is centered on the Great Attractor. That superc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (astronomy)
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the posit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (one million million, or billion in long scale). As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year (365.25 days). Because it includes the time-measurement word "year", the term ''light-year'' is sometimes misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years) which derives from astrometry; it is the distance at which one astronomical unit subtends an angle of one second of arc. Defini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 is part of the Virgo Supercluster, which is part of the Laniakea Supercluster."Earth's new address: 'Solar System, Milky Way, Laniakea ''Nature (journal), Nature'' The large size and low density of superclusters means that they, unlike clusters, expand with the Hubble expansion. The number of superclusters in the observable universe is estimated to be 10 million. Existence [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Abell Clusters
The Abell catalogue is a catalogue of approximately 4,000 galaxy clusters with at least 30 members, almost complete to a redshift of ''z'' = 0.2. It was originally compiled by the American astronomer George O. Abell in 1958 using plates from POSS, and extended to the southern hemisphere by Abell, Corwin and Olowin in 1987. The name "Abell" is also commonly used as a designation for objects he compiled in a catalogue of 86 planetary nebulae in 1966. The proper designation for the galaxy clusters is ACO, as in "ACO 13", while the planetary-nebula designation is the single letter A, as in "A 39". 1–1999 2000–4076 Southern catalogue S1–S1174 See also * Lists of astronomical objects * List of galaxy groups and clusters This article lists some galaxy groups and galaxy clusters. Defining the limits of galaxy clusters is imprecise as many clusters are still forming. In particular, clusters close to the Milky Way tend to be classified as galaxy clusters eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observable Universe
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 objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. There may be 2 trillion galaxies in the observable universe, although that number was reduced in 2021 to only several hundred billion based on data from '' New Horizons''. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction. That is, the observable universe is a spherical region centered on the observer and is unique for every unique observational position. The word ''observable'' in this sense does not refer to the capability of modern technology to detect light or other information from an object, or whether there is anything to be detected. It refers to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell Catalogue
The Abell catalog of rich clusters of galaxies is an all-sky catalog of 4,073 rich galaxy clusters of nominal redshift ''z'' ≤ 0.2. This catalog supplements a revision of George O. Abell's original "Northern Survey" of 1958, which had only 2,712 clusters, with a further 1,361 clustersthe "Southern Survey" of 1989, published after Abell's death by co-authors Harold G. Corwin and Ronald P. Olowin from those parts of the south celestial hemisphere that had been omitted from the earlier survey. The Abell catalog, and especially its clusters, are of interest to amateur astronomers as challenge objects to be viewed in dark locations on large aperture amateur telescopes. The Northern Survey The original catalog of 2,712 rich clusters of galaxies was published in 1958 by George O. Abell (1927–1983), who was then studying at the California Institute of Technology. The catalog, which formed part of Abell's PhD thesis, was prepared by means of a visual inspection of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. The term ''Milky Way'' is a translation of the Latin ', from the Greek ('), meaning "milky circle". From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies. The Milky Way is a barred spiral galaxy with an estimated D25 isophotal diameter of , but only about 1,000 light years thick at the spiral arms (more at the bulg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laniakea Supercluster
The Laniakea Supercluster (; Hawaiian for "open skies" or "immense heaven") is the galaxy supercluster that is home to the Milky Way and approximately 100,000 other nearby galaxies. It was defined in September 2014, when a group of astronomers including R. Brent Tully of the University of Hawaiʻi, Hélène Courtois of the University of Lyon, Yehuda Hoffman of the Hebrew University of Jerusalem, and Daniel Pomarède of CEA Université Paris-Saclay published a new way of defining superclusters according to the relative velocities of galaxies. The new definition of the local supercluster subsumes the prior defined local supercluster, the Virgo Supercluster, as an appendage. Follow-up studies suggest that the Laniakea Supercluster is not gravitationally bound; it will disperse rather than continue to maintain itself as an overdensity relative to surrounding areas. Name The name () means 'immense heaven' in Hawaiian, . The name was suggested by Nawaʻa Napoleon, an assoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and papers reporting original research in relevant fields. Despite the name, the journal is no longer monthly, nor does it carry the notices of the Royal Astronomical Society. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second volume, after the Astronomical Society of London became the Royal Astronomical Society (RAS). Until 1960 it carried the monthly notices of the RAS, at which time these were transferred to the newly established ''Quarterly Journal of the Royal Astronomical Society'' (1960–1996) and then to its successor journal ''Astronomy & Geophysics'' (since 1997). Until 1965, MNRAS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Avoidance, a region near the plane of the Milky Way. Consequently, the cluster is severely obscured by interstellar dust at optical wavelengths. Its mass is estimated to be on the order of 1015 solar masses. ESO 137-001, an example of a jellyfish galaxy, is located in Abell 3627. See also * List of galaxy groups and clusters * Coma Cluster * Eridanus Cluster * Fornax Cluster * Virgo Cluster * X-ray astronomy References External links ESO Press Photos 46a-j/99* NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ... Image of the Day, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 the Milky Way. However, it is inconveniently obscured by our own Milky Way's galactic plane, lying behind the Zone of Avoidance (ZOA), so that in visible light wavelengths, the Great Attractor is difficult to observe directly. In fact, it will not be for another hundred million years that Earth will be on the other side of the Milky Way galaxy, allowing us to see past the galactic plane. The anomaly is observable by its effect on the motion of galaxies and their associated clusters over a region of hundreds of millions of light-years across the universe. These galaxies are observable above and below the ZOA; all are redshifted in accordance with the Hubble flow, indicating that they are receding relative to us and to each other, but the v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antlia Cluster
The Antlia Cluster (or Abell S0636) is a cluster of galaxies located in the Hydra–Centaurus Supercluster. The Antlia Cluster is the third-nearest to the Local Group after the Virgo Cluster and Fornax Cluster. Antlia's distance from Earth is to and can be viewed from Earth in the constellation Antlia. The Antlia Cluster should not be confused with the Antlia Dwarf galaxy. Antlia is classified as a rare '' Bautz–Morgan type III'' cluster, meaning it has no central dominant (cD) brightest cluster galaxy. However, the cluster is dominated by two massive elliptical galaxies, NGC 3268 and NGC 3258, and contains a total of about 234 galaxies. The cluster is very dense compared to other clusters such as Virgo and Fornax, thus containing early-type galaxies and a larger portion of dwarf ellipticals. The cluster is split into two galaxy groups, ''the Northern subgroup'' gravitating around NGC 3268, and ''the Southern subgroup'' centered on NGC 3258. The cluster has an overall redshi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
