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Type-cD Galaxy
The type-cD galaxy (also cD-type galaxy, cD galaxy) is a galaxy morphology classification, a subtype of type-D galaxy, type-D Elliptical galaxy#Sizes and shapes, giant elliptical galaxy. Characterized by a large galactic halo, halo of stars, they can be found near the centres of some rich galaxy clusters. They are also known as supergiant ellipticals or central dominant galaxies. Characteristics The cD-type is a classification in the Galaxy morphological classification, Yerkes galaxy classification scheme, one of two Yerkes classifications still in common use, along with D-type. The "c" in "cD" refers to the fact that the galaxies are very large, hence the adjective supergiant, while the "D" refers to the fact that the galaxies appear diffuse. A backformation of "cD" is frequently used to indicate "central Dominant galaxy"."Uncertainties on Clusters of Galaxies Distances", C. Adami, M.P. Ulmer, 18 July 2000, (accessed 14 April 2010) cDs are also frequently considered the largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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ESO 383-76 Legacy DR10
The European Southern Observatory is an astronomical research organisation. ESO may also refer to: *Employee stock option (also: executive stock option) *'' Ether Saga Odyssey'', a fantasy massively multiplayer online role-playing game *''The Elder Scrolls Online'', a fantasy massively multiplayer online role-playing game *Existential second-order logic *ESO (motorcycles) * Eso (town), Orhionmwon, Edo State, Nigeria Organisations * European Standardisation Organisations: CEN (European Committee for Standardization), CENELEC (European Committee for Electrotechnical Standardisation) and ETSI (European Telecommunications Standards Institute) *Ensemble Studios Online *Edmonton Symphony Orchestra *Energijos skirstymo operatorius (ESO), Lithuanian electricity transmission network operator *Evergreen Symphony Orchestra, an orchestra in Taiwan *Eteläsuomalainen osakunta, a student nation at the University of Helsinki *Libyan External Security Organisation *External Security Organisatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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3C 401
3C 401 is a powerful radio galaxy located in the constellation Draco. It is near the center of a rich cluster of galaxies and dominates the cluster. That is, it is the type-cD galaxy of its cluster. It has a double nucleus, indicating that it is merging with another galaxy. 3C 401 is classified as a Fanaroff and Riley class II radio source (FR II), but has characteristics of both types of sources. FR II radio sources are brightest at the ends of their radio lobes while FR I sources are brightest toward their centers. 3C 401 has hot spots at the ends of its two extended radio lobes, but also has a bright one-sided jet like a FR I source. The spectra of this jet is also intermediate between the spectra of jets in the two types of sources. References Draco (constellation) 401 __NOTOC__ Year 401 ( CDI) was a common year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Vincentius and Fravitus (or, less frequently, ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Kinetic Energy
In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Robert and Halliday, David (1960) ''Physics'', Section 7-5, Wiley International Edition The kinetic energy of an object is equal to the work, or force ( F) in the direction of motion times its displacement ( s), needed to accelerate the object from rest to its given speed. The same amount of work is done by the object when decelerating from its current speed to a state of rest. The SI unit of energy is the joule, while the English unit of energy is the foot-pound. In relativistic mechanics, \fracmv^2 is a good approximation of kinetic energy only when ''v'' is much less than the speed of light. History and etymology The adjective ''kinetic'' has its roots in the Greek word κίνησις ''kinesis'', meaning "motion". The dichoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Dark Matter
In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relativity unless more matter is present than can be observed. Such effects occur in the context of Galaxy formation and evolution, formation and evolution of galaxies, gravitational lensing, the observable universe's current structure, mass position in galactic collisions, the motion of galaxies within galaxy clusters, and cosmic microwave background Anisotropy, anisotropies. Dark matter is thought to serve as gravitational scaffolding for cosmic structures. After the Big Bang, dark matter clumped into blobs along narrow filaments with superclusters of galaxies forming a cosmic web at scales on which entire galaxies appear like tiny particles. In the standard Lambda-CDM model of cosmology, the mass–energy equivalence, mass–energy content o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Dynamical Friction
In astrophysics, dynamical friction or Chandrasekhar friction, sometimes called gravitational drag, is loss of momentum and kinetic energy of moving bodies through gravitational interactions with surrounding matter in space. It was first discussed in detail by Subrahmanyan Chandrasekhar in 1943. Intuitive account An intuition for the effect can be obtained by thinking of a massive object moving through a cloud of smaller lighter bodies. The effect of gravity causes the light bodies to accelerate and gain momentum and kinetic energy (see slingshot effect). By conservation of energy and momentum, we may conclude that the heavier body will be slowed by an amount to compensate. Since there is a loss of momentum and kinetic energy for the body under consideration, the effect is called ''dynamical friction''. Another equivalent way of thinking about this process is that as a large object moves through a cloud of smaller objects, the gravitational effect of the larger object pulls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Virial Mass
In astrophysics, the virial mass is the mass of a gravitationally bound astrophysical system, assuming the virial theorem applies. In the context of galaxy formation and dark matter halos, the virial mass is defined as the mass enclosed within the virial radius r_ of a gravitationally bound system, a radius within which the system obeys the virial theorem. The virial radius is determined using a "top-hat" model. A spherical "top hat" density perturbation destined to become a galaxy begins to expand, but the expansion is halted and reversed due to the mass collapsing under gravity until the sphere reaches equilibrium – it is said to be ''virialized''. Within this radius, the sphere obeys the virial theorem which says that the average kinetic energy is equal to minus one half times the average potential energy, \langle T \rangle = -\frac \langle U \rangle, and this radius defines the virial radius. Virial radius The virial radius of a gravitationally bound astrophysical system i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Baryon
In particle physics, a baryon is a type of composite particle, composite subatomic particle that contains an odd number of valence quarks, conventionally three. proton, Protons and neutron, neutrons are examples of baryons; because baryons are composed of quarks, they belong to the hadron list of particles, family of particles. Baryons are also classified as fermions because they have half-integer Spin (physics), spin. The name "baryon", introduced by Abraham Pais, comes from the Ancient Greek, Greek word for "heavy" (βαρύς, ''barýs''), because, at the time of their naming, most known elementary particles had lower masses than the baryons. Each baryon has a corresponding antiparticle (antibaryon) where their corresponding antiquarks replace quarks. For example, a proton is made of two up quarks and one down quark; and its corresponding antiparticle, the antiproton, is made of two up antiquarks and one down antiquark. Baryons participate in the residual strong force, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Tidal Streams
{{disambiguation ...
Tidal is the adjectival form of tide. Tidal may also refer to: * ''Tidal'' (album), a 1996 album by Fiona Apple * Tidal (king), a king involved in the Battle of the Vale of Siddim * TidalCycles, a live coding environment for music * Tidal (service), a music streaming service * '' Tidal: Occupy Theory, Occupy Strategy'', a magazine associated with the Occupy Wall Street movement See also * Tidal flow (traffic), the flow of traffic thought of as an analogy with the flow of tides * Tidal force, a secondary effect of the force of gravity and is responsible for the tides * Tidal power, energy harnessed by converting energy from tides * Tide (other) A tide is the rise and fall of a sea level caused by the Moon's gravity and other factors. Tide(s) may also refer to: Media * The Tide (Nigeria), ''The Tide'' (Nigeria), a newspaper *Tide (TV series), ''Tide'' (TV series), 2019 Irish/Welsh/Scott ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |