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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 a ... [...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 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Lyon
The University of Lyon (french: Université de Lyon), located in Lyon and Saint-Étienne, France, is a center for higher education and research comprising 11 members and 24 associated institutions. The three main universities in this center are: Claude Bernard University Lyon 1, which focuses upon health and science studies and has approximately 27,000 students; Lumière University Lyon 2, which focuses upon the social sciences and arts, and has about 30,000 students; Jean Moulin University Lyon 3, which focuses upon the law and humanities with about 20,000 students. Members *Claude Bernard University Lyon 1 *Lumière University Lyon 2 *Jean Moulin University Lyon 3 *Jean Monnet University * École Normale Supérieure de Lyon * École centrale de Lyon * École nationale des travaux publics de l'État (ENTPE) * INSA Lyon * Institut d'études politiques de Lyon * VetAgro Sup (previously École Nationale Vétérinaire de Lyon) *École nationale d'ingénieurs de Saint-Étienne, ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydra Supercluster
Hydra generally refers to: * Lernaean Hydra, a many-headed serpent in Greek mythology * ''Hydra'' (genus), a genus of simple freshwater animals belonging to the phylum Cnidaria Hydra or The Hydra may also refer to: Astronomy * Hydra (constellation) * Hydra (moon), a satellite of Pluto Computing * Hydra (chess), a chess computer * Hydra (digital repository) * Hydra (operating system) * Hydra (software) * Hydra 100, a multi-GPU hardware solution * HYDRA Game Development Kit, a development system by André LaMothe * Razer Hydra, a game controller * NEC HYDRAstor, a storage system Fictional entities * Hydra (comics), a fictional organization in the Marvel Universe ** Hydra (Marvel Cinematic Universe), an organisation in the Marvel Cinematic Universe based on the comics counterpart * Hydra (''Dungeons & Dragons''), a fictional monster in ''D&D'' * Hydra (''Transformers''), a character in ''Transformers'' * The Hydra, a fictional organization in '' The Phantom'' * Hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antlia Wall
Antlia (; from Ancient Greek ''ἀντλία'') is a constellation in the Southern Celestial Hemisphere. Its name means "pump" in Latin and Greek; it represents an air pump. Originally Antlia Pneumatica, the constellation was established by Nicolas-Louis de Lacaille in the 18th century. Its non-specific (single-word) name, already in limited use, was preferred by John Herschel then welcomed by the astronomic community which officially accepted this. North of stars forming some of the sails of the ship Argo Navis (the constellation Vela), Antlia is completely visible from latitudes south of 49 degrees north. Antlia is a faint constellation; its brightest star is Alpha Antliae, an orange giant that is a suspected variable star, ranging between apparent magnitudes 4.22 and 4.29. S Antliae is an eclipsing binary star system, changing in brightness as one star passes in front of the other. Sharing a common envelope, the stars are so close they will one day merge to form a single ... [...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, succeedin ... Image of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 supe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horologium Supercluster
The Horologium-Reticulum Supercluster, is a massive supercluster spanning around 550 million light-years. It has a mass of around 1017 solar masses, similar to that of the Laniakea Supercluster, which houses the Milky Way. It is centered on coordinates right ascension and declination , and spans an angular area of 12° × 12°. The nearest part of the supercluster is 700 million light-years away from Earth, while the far end of it is 1.2 billion light-years. It is visible in the constellations Horologium and Eridanus. The Horologium Supercluster has about 5,000 galaxy group A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxie ...s (30,000 giant galaxies and 300,000 dwarf galaxies). It includes the galaxy cluster Abell 3266. Gallery Horologium_reticulum_supercluster.png, Axonometr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, larger than Earth's entire land area combined .Pacific Ocean . '' Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polynesian Navigation
Polynesian navigation or Polynesian wayfinding was used for thousands of years to enable long voyages across thousands of kilometers of the open Pacific Ocean. Polynesians made contact with nearly every island within the vast Polynesian Triangle, using outrigger canoes or double-hulled canoes. The double-hulled canoes were two large hulls, equal in length, and lashed side by side. The space between the paralleled canoes allowed for storage of food, hunting materials, and nets when embarking on long voyages. Polynesian navigators used wayfinding techniques such as the navigation by the stars, and observations of birds, ocean swells, and wind patterns, and relied on a large body of knowledge from oral tradition. Navigators travelled to small inhabited islands using wayfinding techniques and knowledge passed by oral tradition from master to apprentice, often in the form of song. Generally, each island maintained a guild of navigators who had very high status; in times of famine or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs (110 million light-years). The Virgo SC is one of about 10 million superclusters in the observable universe and is in the Pisces–Cetus Supercluster Complex, a galaxy filament. A 2014 study indicates that the Virgo Supercluster is only a lobe of an even greater supercluster, Laniakea, a larger, competing referent of the term Local Supercluster centered on the Great Attractor. Background Beginning with the first large sample of nebulae published by William and John Herschel in 1863, it was known that there is a marked excess of nebular fields in the constellation Virgo (near the north galactic pole). In the 1950s, French–American astronomer Gérard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radial Velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection of the target-observer relative velocity onto the relative direction connecting the two points. In astronomy, the point is usually taken to be the observer on Earth, so the radial velocity then denotes the speed with which the object moves away from the Earth (or approaches it, for a negative radial velocity). Formulation Given a differentiable vector \mathbf \in \mathbb^3 defining the instantaneous position of a target relative to an observer. Let with \mathbf \in \mathbb^3, the instantaneous velocity of the target with respect to the observer. The magnitude of the position vector \mathbf is defined as The quantity range rate is the time derivative of the magnitude ( norm) of \mathbf, expressed as Substituting () into () : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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