An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 399
giant branch
  شاخه‌ی ِ غولان، ~ غولپیکران   
šâxe-ye qulân, ~ qulpeykarân (#)

Fr.: branche des géantes   

A conspicuous family of stars in the → Hertzsprung-Russell diagram composed of red, evolved stars with large sizes. → giant star; → red giant.

giant; → branch.

giant H II region
  ناحیه‌ی ِ II H یِ غولپیکر   
nahiye-ye H II-ye qulpeykar

Fr.: région H II géante   

An → H II region emitting at least 1050 → Lyman continuum photons per second, or about 10 times → Orion nebula. Such an H II region should be powered by at least one O3V star or by at least a dozen → O-type and tens → B-type stars. Our nearest giant H II region is → NGC 3603. Some other Galactic giant H II regions are: → Lagoon Nebula, M17, W31, W51A, and NGC 3576.

giant; → H II; → region.

giant magnetoresistance (GMR)
  مغنات-ایستادگی ِ کلان، ایستادگی ِ مغناتیسی ِ ~   
meqnât-istâdegi-ye kalân, istâdegi-ye meqnâtisi-ye ~

Fr.: magnétorésistance géante   

A quantum mechanical phenomenon where the resistance of certain materials drops dramatically upon application of a magnetic field in certain structures composed of alternating layers of magnetic and nonmagnetic metals. The basis of the GMR is the dependence of the electrical resistivity of electrons in a magnetic metal on the direction of the electron spin, either parallel or anti-parallel to the magnetic moment of the layers. The 2007 Nobel Prize in physics was awarded to the French physicist Albert Fert (1938-) and German physicist Peter Grünberg (1939-) for the discovery of GMR.

giant; magneto- combining form of → magnet; → resistance.

giant molecular cloud (GMC)
  ابر ِ مولکولی ِ غولپیکر   
abr-e molekuli-ye qulpeykar (#)

Fr.: nuage moléculaire géant   

A massive complex of → interstellar gas and → dust, consisting mostly of → molecular hydrogen, that typically stretches over 150 light-years and contains several hundred thousand → solar masses. Giant molecular clouds are the principal sites of star formation. → molecular cloud.

giant; → molecular; → cloud.

giant planet
  سیاره‌ی ِ غولپیکر   
sayyâre-ye qulpeykar (#)

Fr.: planète géante   

A planet much more massive than Earth. The solar system has four giant planets: → Jupiter, → Saturn, → Uranus, and → Neptune.

giant; → planet.

giant star
  ستاره‌ی ِ غولپیکر   
setâre-ye qulpeykar (#)

Fr.: étoile géante   

A high-luminosity star that has evolved off the → main sequence and lies above the main sequence on the → Hertzsprung-Russell diagram. A member of the → giant branch. → red giant.

giant; → planet.

  کوژ، کوژماه   
kuž, kužmâh (#)

Fr.: gibbeux   

An adjective applied to the phase of the Moon (or a planet) when it is more than half full, but less than entirely full.

From L.L. gibbous "hunchbacked," from L. gibbus "hump, hunch;" cf. Mod.Pers. kaž "crooked, bent, being aside;" Skt. kubja- "hump-backed, crooked;" Pali kujja- "bent;" Lith. kupra "hump."

Kuž "humped," Mid.Pers. kôf "hill, mountain; hump" (Mod.Pers. kuh, "mountain"), kôfik "humpbacked," O.Pers. kaufa-, Av. kaofa- "mountain;" mâh, → moon.

Gibbs canonical distribution
  واباژش ِ هنجاروار ِ گیبس   
vâbâžeš-e hanjârvâr-e Gibbs

Fr.: distribution canonique de Gibbs   

The probability distribution of the various possible states of a certain → quasi-closed subsystem.

Gibbs free energy; → canonical; → distribution.

Gibbs free energy
  کاروژ ِ آزاد ِ گیبس   
kâruž-e âzâd-e Gibbs

Fr.: énergie libre de Gibbs   

The total energy needed to create a thermodynamic system minus the energy provided the environment. It is defined by G = U + PV -TS, where U is the → internal energy, T the → absolute temperature, S the → entropy, P the → pressure, and V is the final → volume. Same as the → Gibbs function and → thermodynamic potential.

Named after Josiah Willard Gibbs (1839-1903), an American physicist who played an important part in the foundation of analytical thermodynamics; → free; → energy.

Gibbs function
  کریای ِ گیبس   
karyâ-ye Gibbs

Fr.: fonction de Gibbs   

Same as → Gibbs free energy.

Named after Josiah Willard Gibbs (1839-1903), an American physicist who played an important part in the foundation of analytical thermodynamics; → function.

giga- (G)
gigâ- (#)

Fr.: giga-   

A prefix that is used to represent 109 in the SI system.

From Gk. gigas, → giant.

gigahertz (GHz)
gigâhertz (#)

Fr.: gigahertz   

A unit of → frequency, equal to 106 Hz.

giga-; → hertz.

doqâb (#)

Fr.: monture à la Cardan, cardan   

1) A support component of a gyroscope, which allows the axis to move freely.
2) A mechanical mounting frame having two mutually perpendicular axes of rotation.

Gimbal, alteration of gemel "twin," from M.E., gemelles, from O.Fr. gemeles (Fr. jumeau, jumelle), from L. gemellus, diminutive of geminus "twin;" cf. Pers. Kermâni dialect jomoli "twin;" → Gemini.

Doqâb, from do "two" (Mid.Pers. do; Av. dva-; cf. Skt. dvi-; Gk. duo; L. duo; O.E. twa; Ger. zwei) + qâb "frame," from Turkish.

Gl 229B
Gl 229B

Fr.: Gl 229B   

The prototype of → T dwarfs discovered by Nakajima et al. (1995, Nature 378, 463). This → brown dwarf lies 21.8 → light-years away and orbits a primary star of type M1 V every about 40 years. It has a temperature of less than 1,200 K, and a mass approximately 20-50 times that of Jupiter. Its luminosity is about 2 x 10 -6 that of the Sun.

Gl, referring to the → Gliese catalogue.

yaxzâr (#)

Fr.: glacier   

An extended mass of ice formed from snow falling and accumulating over the years and moving very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers (

From Fr. glacier, from O.Fr. glace "ice," from V.L. glacia, from L. glacies "ice," probably from PIE root *gel-, → cold.

Yaxzâr, from yax, → ice, + -zâr suffix denoting profusion and abundance, as in šurezâr "infertile, salty ground; nitrous earth," xoškzâr "arid land," kârzâr "a field of battle; combat," marqzâr "a place abounding with the grass," and so forth.


Fr.: lumière éblouissante   

1) A very harsh, bright, dazzling light.
2) A type of → light pollution which is a blinding light within the field of vision. It compromises security and safety.

M.E. glaren; cognate with M.Du., M.L.G. glaren; akin to glass.

Xirtâv, literally "dazzling light," from xir, from xiré konandé, "dazzling," from xiré "much, many; obstinate; perverse; unwilling;" + tâv, variant tâb, tâbidan "to shine," → luminous.

šišé (#)

Fr.: verre   

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or phosphoric oxides.

From O.E. glæs, from W.Gmc. *glasam (M.Du. glas, Ger. Glas), from PIE base *gel-/*ghel- "to shine, glitter."

Šišé "glass;" Mid.Pers. šišag.

glass blank
  گرده‌ی ِ شیشه   
gerde-ye šišé

Fr.: disque de verre   

A mass of glass ready to be shaped into a telescope mirror. Same as → glass disk.

glass; blank, from O.Fr. blanc "white, shining," from Frank. *blank "white, gleaming," of W.Gmc. origin (cf. O.E. blanca "white horse"), from P.Gmc. *blangkaz, from PIE *bhleg- "to shine."

Gerdé, → disk; šišéglass.

glass disk
  گرده‌ی ِ شیشه   
gerde-ye šišé

Fr.: disque de verre   

Same as glass blank.

glass; → disk.

glass filter
  پالایه‌ی ِ شیشه‌ای   
pâlâye-ye šiše-yi

Fr.: filtre de verre   

A filter used in → broad-band photometry. The → bandwidth ranges usually between 30 and 100 nm.

glass; → filter.

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