An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1307
Chandra X-ray Observatory
  نپاهشگاه ِ پرتوهای ِ X ِ چاندرا   
nepâhešgâh-e partowhâ-ye X-e Chandra

Fr.: Observatoire des rayons X Chandra   

An astronomy satellite launched by NASA in 1999 July, specially designed to detect X-ray emission from very hot regions of the Universe such as exploded stars, clusters of galaxies, and matter around black holes. Chandra carries a high resolution mirror (aperture 1.2 m, focal length 10 m), two imaging detectors (HRC and ACIS), and two sets of transmission grating spectrometer (LETG and HETG). Important Chandra features are: an order of magnitude improvement in spatial resolution, good sensitivity from 0.1 to 10 keV, and the capability for high spectral resolution observations over most of this range. Chandra was initially given an expected lifetime of 5 years, but on 4 September 2001 NASA extended its lifetime to 10 years "based on the observatory's outstanding results." Among the results obtained using Chandra one can mention the spectacular image of the → supernova remnant Cassiopeia A. See also → X-ray astronomy.

Initially called Advanced X-ray Astrophysics Facility (AXAF), the satellite was renamed the Chandra X-ray Observatory in honor of Subrahmanyan Chandrasekhar, the 1983 Nobel Prize in Physics, → Chandrasekhar limit. Moreover, Chandra, or candra- means "moon" or "shining" in Skt., from cand- "to give light, shine;" cf. Gk. kandaros "coal;" L. candela "a light, torch," from candere "to shine;" → X-ray; → Observatory.

Chandrasekhar limit
  حدِ چاندراسکهار   
hadd-e Chandrasekhar (#)

Fr.: limite de Chandrasekhar   

A limiting mass of about 1.44 Solar masses that the theory predicts a non-rotating → white dwarf can attain without collapsing to become a → neutron star or a → black hole. Over this → critical mass, the degeneracy pressure will be unable to bear the load of the bulk mass.

Named after Subrahmayan Chandrasekhar (1910-1995), Indian-born American astrophysicist who, with William A. Fowler, won the 1983 Nobel Prize for Physics for his research on white dwarfs; → limit.

  ۱) دگرشد، دگرکرد، دگرش؛ ۲) دگر‌شدن، دگر‌کردن، دگریدن، آلشیدن   
1) degaršod, degarkard, degareš, âleš 2) degar šodan (#), degar kardan (#), âlešidan, degaridan

Fr.: 1) changement; 2) changer   

1) The act of changing; alteration or variation of any kind. → adiabatic change, → canonical change, → polytropic change, → secular change, → exchange.
2a) ( To alter, modify, or make different; to make to pass from one state to another; to exchange.
2b) To transform or convert.
2c) To substitute another or others for; exchange for something else, usually of the same kind.
2b) (v.intr.) To undergo change.

M.E., from O.Fr. changier, from L.L. cambiare, from L. cambire "to exchange, barter," of Celtic origin, cf. Breton kamm "curved, bent;" Gk. kampe "a corner, a joint;" L. campus "a field;" Lith. kampus "corner;" PIE *kamb- "to bend, crook."

Degaršod, from degar, digar "another, other" (Mid.Pers. dit, ditikar "the other, the second," O.Pers. duvitiya- "second," Av. daibitya-, bitya- "second," Skt. dvitiya- "second," PIE *duitiio- "second") + šod, past stem and contracted infinitive of šodan "to become; to be; to be elapsed;" (Mid.Pers. šutan, O.Pers. šyav-, Av. šav-, šyav- "to move, to go away from" (perf. ptcpl. pass. šuta-); cf. Skt. cyavate "stirs himself, goes," stem cyu-, Gk. kinein "to move," L. ciere "to move, set in motion, stir," PIE *kei- "to move to and fro"); degarkard with kardan, → -ize; degaridan, infinitive from degar + -idan, → -ize.
Âleš, ultimately from Proto-Ir. *harH- "to barter, trade, exchange, pay tribute" (Cheung 2007); cf. Mid.Pers. harg, halg "duty, tribute; work, effort" (loaned in Ar. as xarj "expense," harâj "tax"); Sogd. arsk "work, action;" Yaghnobi ark "work;" Yidgah horγ, Munji hôr(g) "work;" Khotanese hära- "thing, possession;" prefixed forms from *hi-harH-: Mod.Pers. wihir- "change;" Mod.Pers. guhar, gohari, gahul, gahulidan "to change, exchange."

  ۱) ورشون؛ ۲) شیوار   
1) varšun; 2) šivâr

Fr.: chaos   

1a) General: A condition or place of great disorder or confusion.
1b) Math., Physics: Highly disordered evolution of some → dynamical systems which is sensitively dependent on → initial conditions. In a → chaotic system the → aperiodic, → nonlinear evolution grows → exponentially with time. Ordinary chaos is not → turbulence, but turbulence is always chaotic.
2) In → astrogeology, a distinctive area of fractured terrain on a planet or satellite, e.g. Gorgonum Chaos located in the southern hemisphere of Mars.

Chaos, in Gk. mythology and cosmology, the void existing at the beginning of the creation, as evoked in Hesiod's (c. 850 B.C.) Theogony. However, the meaning of chaos, used by Hesiod, is a matter of debate. Some have interpreted it as the primeval absence of order (hence → confusion). Subsequently, the Roman writer Ovid (43 BC-17? AD) described Chaos in his Metamorphoses as an unordered and formless primordial mass, and opposed Chaos to Cosmos "the ordered universe."

Chaos "gaping void," from L. chaos, from Gk. khaos "abyss, that which gapes wide open, is vast and empty," from *khnwos, from PIE base *gheu-, *gh(e)i- "to gape."

1) Varšun, from Tabari varâšun, Gilaki varâšin, daršin, uršin all meaning "confused, unordered, untidy," cf. Qomi šur-o-šin "chaos, confusion". The stem šun-/šin- is related to Mod.Pers. šân- in afšândan, šândan "to disperse, scatter, stew" (Mid.Pers. afšândan "to spread, scatter"), Gilaki šondan "to disperse," Hamadani šuândan "to derange, disorder," Laki veršânâ "to disperse, scatter," Šuštari šayn "to shake, agitate," Kermâni owšin "a winnowing fork to separate chaff from the grain," Laki šovâné "scattered household furniture," Tabari timšan "sowing seeds;" all ultimately from Proto-Ir. *šan- "to shake;" see also → confuse. The prefix var-, variant bar- "up, over" (as well as dar- "in"), denotes "disorder, confusion" as in darham barham "upside-down, helter-skelter".
2) Šivâr "depression between two terrains," from Tabari; probably a variant of šiyâr, → groove.

chaos theory
  نگره‌ی ِ ورشون   
negare-ye varšun

Fr.: théorie du chaos   

The theory of unpredictable behavior that can arise in systems obeying deterministic scientific laws.

theory; → chaos.

  ورشونگین، ورشونناک   
varšungin, varšunnâk

Fr.: chaotique   

Or, or relating to → chaos.

Chaotic, adj. from → chaos.

chaotic behavior
  رفتار ِ ورشونگین   
raftâr-e varšungin

Fr.: comportement chaotique   

The behavior of a → chaotic system.

chaotic; → behavior.

chaotic system
  راژمانِ ورشونگین   
râžmân-e varšungin

Fr.: système chaotique   

A system that is → deterministic through → description by mathematical rules but can evolve highly → nonlinearly depending on → initial conditions. See also → chaos.

chaotic; → system.


Fr.: chaoticité   

The condition of being → chaotic.

chaotic; → -ity.

Chaplygin gas
  گاز ِ چاپلیگین   
gâz-e Chaplygin

Fr.: gaz de Tchaplyguin   

In → dark energy models, a hypothetical fluid that can lead to cosmic acceleration at late times. In its simplest form, the Chaplygin gas has the → equation of statep = - A/ρ, where p and ρ denote the → pressure and → energy density, respectively, and A is a positive model parameter. This equation was introduced by Chaplygin (1904, Sci. Mem. Moscow Univ. Math., 21) to study the lifting force on a plane wing in aerodynamics.

Named after Sergey Chaplygin (1869-1942), Russian physicist; → gas.

Chappuis band
  باند ِ شپویی   
bând-e Chappuis

Fr.: bande de Chappuis   

A band in the → absorption spectrum of → ozone (O3) extending in the → visible from 400 nm to 700 nm. → Hartley band, → Huggins band.

J. Chappuis, Acad. Sci., Paris, C. R. 91, 985 (1880).

  ۱) سرشت، سرشتار؛ ۲) سرشتار؛ ۳) دخشه   
1) serešt (#), sereštâr; 2) sereštâr; 3) daxšé (#)

Fr.: 1, 3) caractère; 2) personnage   

1a) The aggregate of features and traits that form the individual nature of some person or thing.
1b) One such feature or trait; characteristic.
2) A person represented in a play, film, story, etc; role. See also → personage (
3) Computers: One of a set of symbols, such as letters or numbers, that are arranged to express information; the numerical code representing such a character.

M.E. carecter "distinctive mark," from O.Fr. caractère, from L. character, from Gk. kharakter "graving tool, its mark," from kharassein "to engrave," from kharax "pointed stick."

1, 2) Serešt "nature, temperament, constitution; mixed," sereštan "to mix, mingle; knead;" serišom "glue;" Mid.Pers. srištan "to mix, knead;" cf. Av. ham-sriš- "to put together;" Skt. śres- "to cling, stick, be attached;" Proto-Ir. root *sraiš- "to put together, attach" (Cheung 2007).
Sereštâr with -âr, contraction of âvar agent noun of âvardan "to bring; to cause, produce," → format.
3) Daxšé, variants dâq "a brand, a mark burned on the skin of an animal with a hot iron," Gilaki dajé "a brand," Hamadani daj "sign placed on a heap of harvest indicating identity or ownership," Mid.Pers. daxšag "mark, sign, charactersitic; (monthly) signs (of women)", dazidan "to burn, scorch," Av. daxša- "sign, mark, defect," from dag- "to burn," dažaiti "burns," cf. Skt. dah- "to burn," dahati "burns," Gk. tephra "ash," L. favilla "glowing ashes," Lith. dagas "hot season," O.Prus. dagis "summer," P.Gmc. *dagaz, Ger. Tag, E. day; PIE *dhegwh- "to burn."

characteristic age
  سن ِ سرشتاری   
senn-e sereštâri

Fr.: âge caractéristique   

Of a pulsar, a normalized period of rotation assumed to be a good approximation to pulsar's true age.

characteristic; → age.

characteristic curve
  خم ِ سرشتاری   
xam-e sereštâri

Fr.: courbe caractéristique   

Graph representing an optical film's response to the amount of light falling on it.

characteristic; → curve.

characteristic equation
  هموگش ِ سرشتاری   
hamugeš-e sereštâri

Fr.: équation caractéristique   

Physics: An analytical relationship between a set of physical variables that determines the state of a physical system.
Math.: The equation which is solved to find a matrix's eigenvalues, also called the characteristic polynomial.

characteristic; → equation.

characteristic mass
  جرم ِ سرشتاری   
jerm-e sereštâri

Fr.: masse caractéristique   

A typical or most likely mass for the formation of an astronomical object. In current star formation models, it is of order of a few tenths of a → solar mass.

characteristic; → mass.

characteristic thermal energy
  کاروژ ِ گرمایی ِ سرشتاری   
kâruž-e garmâyi-ye sereštâri

Fr.: énergie thermique caractéristique   

The quantity kT in the → Maxwell-Boltzmann distribution law, where k is → Boltzmann's constant and T the gas temperature. See also → thermal energy.

characteristic; → thermal; → energy

  ۱) سرشتارش؛ ۲) تنومسا سازی   
1) sereštâreš 2) tanumsâ sâzi

Fr.: 1) caractérisation; 2) représentation des caractères   

1) The act of describing the character or qualities of someone or something.
2) The artistic representation (as in fiction or drama) of human character or motives (

characterize; → -tion.


Fr.: caractériser   

1) To mark or distinguish as a characteristic; be a characteristic of.
2) To describe the character or individual quality of.
3) To attribute character to (

character; → -ize.

zoqâl (#)

Fr.: charbon de bois   

A black amorphous substance produced by heating wood or other natural organic matter in the absence of air. It is used as a fuel.

M.E. charcole, maybe from cherre "char" + cole, → coal.

Zoqâl "live coal, charcoal," variant sokâr; Sogd. askâr; Pashto skor-; Khotanese skara, probably ultimately from Proto-Ir. *uz-gar-, from *uz- "out," → ex-, + *gar "to heat, kindle fire, cook;" cf. Tabari kalə "furnace," kəlen "ash;" Laki koira; Kurd. kulan, kulandan "to cook;" related to garm "warm;" cf. Skt. ghar- "to burn," PIE root *gwher- "to warm, be warm," → warm.

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