An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1223
cooling process
  فراروند ِ سردش   
farâravand-e sardeš

Fr.: processus de refroidissement   

The process of → radiative cooling in which the → temperature of an astrophysical system decreases due to the radiation of a major → emission line. For example, → molecular → emission at → millimeter wavelengths and → submillimeter wavelengths results in decreasing the temperature in molecular clouds. At temperatures less than 300 K, the main → coolant is the → carbon monoxide (CO) molecule which contains most of the carbon. Similarly, the → [C II] line is a major coolant in → photodissociation regions. See also → line cooling, → cooling time.

cooling; → process.

cooling time
  زمان ِ سردش   
zamân-e sardeš

Fr.: temps de refroidissement   

1) The time in which a → white dwarf cools to half its temperature. It depends on the composition, the mass, and the actual luminosity at some point in time. Cooling time is given by the relation: t = 8.8 × 106 (12/A) (M)5/7 (μ/2)-2/7 (L)-5/7 in years, where M and L are mass and luminosity in solar units, A the mean → atomic mass, and μ the → mean molecular weight (Iben & Tutukov, 1984, ApJ 282, 615). See also → Mestel theory; → white dwarf crystallization.
2) The time needed by a → plasma to radiate its thermal energy. The cooling time is directly proportional to the square root of the temperature and inversely proportional to the density. It turns out that for the → intercluster medium in a → cluster of galaxies this time is longer than the → age of the Universe. At the centers of some clusters, however, the cooling time is smaller than the age of the Universe due to the presence of a → cooling flow.

cooling; → time.

  ۱) همارا؛ ۲) هم‌آراستن   
1) hamârâ (#); 2) hamârâstan

Fr.: 1) coordonnée; 2) coordonner   

1) Any of a series of numbers which, in relation to a given → frame of reference, locate a point in space. See also: → astronomical coordinatescanonical coordinatesCartesian coordinatescelestial coordinatescylindrical coordinatesequatorial coordinatesGalactic coordinatesgeneralized coordinatespolar coordinatesspherical coordinatesprecessed coordinatestopocentric coordinates.
2) To place in the same order or rank; to organize in a concordant operation.

From L. co- "together," → com- + orinatus, p.p. of ordinare "to put in order, arrange," from ordo "order."

Hamârâ, from ham- "together," → com- + ârâ stem of ârâstan "to arrange, to set in order, adorn," Mid.Pers. ârây-, ârâstan "to arrange, adorn," O.Pers. râs- "to be right, straight, true," râsta- "straight, true" (Mod.Pers. râst "straight, true"), râd- "to prepare," Av. râz- "to direct, put in line, set," Av. razan- "order," Gk. oregein "to stretch out," L. regere "to lead straight, guide, rule," p.p. rectus "right, straight," Skt. rji- "to make straight or right, arrange, decorate," PIE base *reg- "move in a straight line."

coordinate system
  راژمان ِ همارا   
râžmân-e hamârâ

Fr.: système de coordonnées   

Math: A system for locating each point in space by a set of numbers.
Astro: Values in a reference system used to relate the position of a body on the celestial sphere. Four main coordinate systems are utilized in astronomy: the equatorial, horizontal, ecliptic, and galactic coordinates systems.

coordinate; → system.

coordinate time
  زمان ِ همارا   
zamân-e hamârâ

Fr.: temps-coordonnée   

In relativity, the proper time in the specified reference frame. Because of time dilation, this may differ from the time experienced by any participant in the events being considered. It is the time basis (or coordinate) to be used in the theory of motions referred to this system.

coordinate; → time.

Coordinated Universal Time (UTC)
  زمان ِ جهانی ِ هم‌آراسته   
zamân-e jahâni-ye hamrârâsté

Fr.: temps universel coordonné   

An international high-precision time standard based on the Greenwich Mean Time and adjusted to compensate for divergence from atomic time. It is based on the non-uniform rotation of the Earth (UT1) and the perfectly uniform international atomic time (TAI). UTC differs from TAI by the total number of → leap seconds, so that UT1-UTC stays smaller than 0.9 sec in absolute value.

coordinate; → universal; → time.


Fr.: coordination   

The act or state of coordinating or of being coordinated.

Verbal noun of → coordinate.

coordination compound
  چندساخت ِ هم‌آرایش   
candsâxt-e hamârâyeš

Fr.: composé de coordination   

A chemical compound in which a group of atoms or ions are attached by a coordination bond to a usually metallic central atom or ion.

coordination; → compound.

coordination lattice
  جاره‌ی ِ هم‌آرایش   
jâre-ye hamârâyeš

Fr.: réseau de coordination   

Crystallography: The crystal structure of a → coordination compound.

coordination; → lattice.

coordination number
  شمار ِ هم‌آرایش   
šomêr-e hamârâyeš

Fr.: nombre de coordination   

1) Crystallography: The number of nearest neighbors of an atom or ion in a → crystal lattice. A large coordination number indicates that the structure is more closely packed.
2) Chemistry: The number of atoms, ions, or molecules surrounding a central atom or ion in a complex.

coordination; → number.

Copenhagen Interpretation
  آزند ِ کوپنهاگ   
âzand-e Kopenhâg

Fr.: interprétation de Copenhague   

A general heading which covers a wide variety of complex views on → quantum theory. As the first and the founding interpretation of the → quantum mechanics, it was developed in the late 1920's mainly by the Danish physicist Niels Bohr, but also Werner Heisenberg, Max Born and other physicists who made important contributions to the overall understanding of this field. Bohr expressed himself on the subject at various meetings and later published several articles and comments, but he never wrote a systematic and complete version of his views. There is not a unique Copenhagen Interpretation but various more or less complete versions, the common denominator of which is mainly the work of Bohr. Among those opposed to the Copenhagen Interpretation have been Albert Einstein, Erwin Schrödinger, Louis de Broglie, Max Planck, David Bohm, Alfred Landé, Karl Popper, and Bertrand Russell. The Copenhagen Interpretation recognizes that the deterministic picture of the universe that works so well at the macroscopic level does not work for the world at the quantum level. The universe at the quantum level is predictable only in a statistical sense. This implies that we can never really know the nature of quantum phenomena. The four cornerstones of the Copenhagen Interpretation are: → wave-particle duality, the probability → wave function, the → uncertainty principle, and the significance of the → observer. The observer is of the utmost importance because he causes the reality to unfold in the way it does. The key feature of the Copenhagen Interpretation is a concept known as the → collapse of the wave function, for which there is no known physical explanation; see also → Schrodinger's cat.

Copenhagen, from Dan. København "merchant's port," from køber "merchant" ("buyer") + havn "port," from the fact that the originator and chief interpreter of this school was Niels Bohr whose headquarters was in Copenhagen; → interpretation.

Copernican model
  مدل ِ کوپرنیک   
model-e Kopernik

Fr.: modèle copernicien, ~ de Copernic   

A model of the Solar System proposed by Copernicus in which the Sun lies at the center with the planets orbiting around it. In this model, the Earth is a planet, and the Moon is in orbit around the Earth, not the Sun. The stars are distant objects that do not revolve around the Sun. Instead, the Earth is assumed to rotate once in 24 hours, causing the stars to appear to revolve around the Earth in the opposite direction. This model readily explained both the varying brightness of the planets and the → retrograde motion. In the Copernican model the planets executed uniform circular motion about the Sun. As a consequence, the model could not explain all the details of planetary motions on the celestial sphere without → epicycles of the → Ptolemaic system. However, the Copernican system required many fewer epicycles than its predecessor because it moved the Sun to the center. Hence, Copernicus borrowed elements from variants of the Ptolemaic system developed by Middle Eastern astronomers, mainly the Iranian Nasireddin Tusi (1201-1274) and the Damascene Ibn al-Shatir (1304-1375), which Copernicus apparently knew about.

Nicolaus Copernicus (1473-1543), the L. rendition of the Polish original name Mikołaj Kopernik, author of the epoch making work De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), published in 1543, in which he exposed his heliocentric system; → model.

Copernican principle
  پروز ِ کوپرنیکی   
parvaz-e Koperniki

Fr.: principe copernicien   

1) Physics: A basic statement that there should be no "special" observers to explain the phenomena. The principle is based on the discovery by Copernicus that the motion of the heavens can be explained without the Earth being in the geometric center of the system, so the Aristotelian/Ptolemaic assumption that we are observing from a special position can be given up.
2) Exobiology: By extension, human beings and the Earth are not at the centre of the → Universe and therefore are not "special". Life would therefore be commonplace. Compare → anthropic principle.

Copernican model; → principle.

coplanar forces
  نیروهای ِ هم-هامن   
niruhâ-ye ham-hâmon

Fr.: forces coplanaires   

A system of forces acting on a body that all are in the same plane.

com- + planar adj. from → plane.

mes (#)

Fr.: cuivre   

A malleable, ductile, reddish metal with a bright luster that is known from antiquity, and has been mined for some 5000 years; symbol Cu. → Atomic number 29; → atomic weight 63.546; → melting point 1,083.4°C; → boiling point 2,567°C; → specific gravity 8.96 at 20°C. Copper is an excellent conductor of heat and electricity and is widely used for various purposes, either pure or in numerous alloys such as bronze and brass in combination with → tin and → zinc. Its → radioactive isotopes have half-lives from 5.10 min (66Cu) to 61.0 hr (67Cu). Copper is mostly created inside → massive stars, via the → s-process, after they leave the → main sequence.

M.E. coper; O.E. coper, copor; cf. O.N. koparr, Ger. Kupfer, the original Germaic word from L.L. cuprum, contraction of L. Cyprium (æs) "Cyprian (metal)," referriing to the island which was the primary source of copper for the Romans, after Gk. Kyprios "Cypress," literally "land of cypress trees."

Mes "copper," of unknown origin; maybe related to Skt. māsaka- "a weight of gold;" Pali māsa- "a small coin, of copper, of very low value;" Prakrit māsa-.

pacen (#)

Fr.: copie   

A reproduction, imitation; a thing made to be like another.

M.E. copie, from O.Fr. copie, from M.L. copia "reproduction, transcript," from L. copia "plenty," from → com- "with" + ops "power, wealth."

Pacen, from Mid.Pers. pacên "copy," ultimately from Proto-Ir. *pati-cak- "strike against, beat through," i.e. "stamp;" from *pati- + *cak- "to strike;" compare with Ger. Durchschlag "copy" literally "striking through;" related to câk "fissure."

  تار، ریسمان   
târ (#), rismân (#)

Fr.: corde   

1) A string or thin rope made of several strands braided, twisted, or woven together.
2) A cordlike structure (

M.E., from O.Fr. corde "rope, string, cord," from L. chorda "string of a musical instrument, cat-gut," from Gk. khorde "string, catgut, chord, cord," from PIE root *ghere- "intestine" (



Fr.: Cordelia   

The innermost of → Uranus' known satellites. Cordelia has a diameter of 26 km and orbits Uranus at a mean distance of 49,752 km. It was discovered from the images taken by Voyager 2 in 1986. Cordelia is the inner → shepherd moon for Uranus's Epsilon ring. → Ophelia.

Named after the daughter of Lear in Shakespeare's play King Lear.


Fr.: cœur, noyau   

1) The central region of a star in which energy is generated by → thermonuclear reactions.
2) The central region of a planet or satellite which has a → differentiated interior.
3) The innermost and densest layer of the Earth, lying from 2890 km to 6360 km beneath the surface. It consists primarily of the metals iron and nickel, and is divided into the → outer core, which is believed to be liquid, and the → inner core, which is believed to be solid.
4) The central region of a → star cluster.
5) A flat → density profile representing the distribution of stars in the central region of a galaxy. Cores are found in high mass galaxies. They are believed to result from the interaction of a central → supermassive black hole with another merging black hole.
6) A progenitor of → protostars. → dense core.
7) → reactor core.

Probably from O.Fr. cœur "core of fruit," literally "heart," from L. cor "heart," cf. Gk. kardia: P.Gmc. *khertan- (O.E. heorte, E. heart, Ger. Herz, Bret. kreiz "middle"), Skt. hrd-; Av. zərəd-; Mid.Pers. dil; Mod.Pers. del; Baluci zird; Arm. sirt; PIE base *kerd- "heart".

Maqzé, from maqz "kernel; brain; marrow" + nuance suffix . Mod.Pers. maqz from Mid.Pers. mazg "brain; marrow," Av. mazga- "marrow; brain" cf. Skt. majján- "marrow," P.Gmc. *mazga-, O.E. mearg "marrow," Lith. smagenes "brain," O.H.G. mark "marrow," PIE base *mozgho- "marrow, brain".

core collapse
  رمبش ِ مغزه   
rombeš-e maqzé

Fr.: effondrement de cœur   

The collapse of a → massive star's core at the → final → stages of its → evolution when the core consists entirely of → iron (→ iron core). Since iron cannot burn in → nuclear reaction, no energy is generated to support the → gravitational collapse. The result will be a → supernova explosion of → Type Ib, → Type Ic, or → Type II. See also → core-collapse supernova.

core; → collapse.

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