An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 667
ergodik (#)

Fr.: ergodique   

The property of a dynamical system such that in an interval of sufficient duration, it will return to states that are closely similar to previous ones.

From → erg + Gk. (h)od(os) "way, road" + → ic.


Fr.: ergonomie   

The study of the relationship between people and their working environment, in particular its effect on a person's efficiency. Ergonomics is applied in designing equipment and office systems to maximize productivity by reducing discomfort and fatigue of people in their workplace.

From Gk. ergon "work," → erg, + -nomics, → -nomy, → -ics.

Varzdâtik, from varz "work, " cognate with Gk. ergon, → erg, + dâtik "law, rule," → -nomy.


Fr.: ergosphère   

The region between the → event horizon and the → stationary limit of a rotating → Kerr black hole. It is possible for a particle falling inside the ergosphere to break into two parts, one of which will fall into the black hole and the other will come out.

erg + → sphere.

Rud (#)

Fr.: Eridan   

The River. An extensive constellation in the southern hemisphere that takes windings between 1h20 and 5h 10m right ascension, 0° to 58° south declination. Despite its size, there are not many bright stars in this constellation. Notable are → Achernar and ε Eri, a dwarf star of magnitude 4.6 and type K2, which is just 10.7 light years away. Abbreviation: Eri; genitive: Eridani.

From Gk. Eridanos, a river god, a son of Oceanus and Tethys, and father of Zeuxippe. A purely mythical river which may have been named Eridanos ("Early Burnt") from the story of Phaethon, the boy who attempted to drive the chariot of the sun, and fell flaming into the waters of this mythical river.

Rud, → river.

Eris (#)

Fr.: Eris   

A → dwarf planet which is a → trans-Neptunian object (TNO) with an orbital → eccentricity of 0.44, an → inclination of 44 degrees and a surface composition very similar to that of → Pluto. It orbits the Sun as far as twice Pluto's distance from the Sun. → Occultation observations carried out in 2010 were used to measure the size of Eris accurately. Eris's newly determined diameter is 2326±12 km. The observations show that Eris is an almost perfect twin of Pluto in size. They also reveal a very reflective surface, with an → albedo of 0.96, suggesting that it is uniformly covered in a thin layer of ice, probably a frozen atmosphere (Sicardy et al. 2011, Nature 478, 493). Like Pluto, Eris has a moon, which has been officially named by the → International Astronomical Union as (136199) Eris I (→ Dysnomia). The informal names of Eris were Xena and 2003 UB313.

Named after Eris the Gk. goddess of chaos and strife. She created a quarrel among goddesses that led to the Trojan War.

farsâyeš (#)

Fr.: érosion   

Geology: The act or state of eroding; state of being eroded.
A general term applied to the wearing away and movement of earth materials by the action of water, glaciers, winds, gravity, etc.

From M.Fr. erosion, from L. erosionem (nom. erosio), from erodere "to gnaw away," from → ex- "away" + rodere "to gnaw, eat away" (cf. Fr. and E. animal rat).

Farsâyeš, from far- intensive prefix "much, abundant" (Mid.Pers. fra- "forward, before; much; around;" O.Pers. fra- "forward, forth;" Av. frā, fərā-, fra- "forward, forth; excessive;" cf. Skt. prá- "before; forward, in fron;" Gk. pro "before, in front of;" L. pro "on behalf of, in place of, before, for;" PIE *pro-) + verbal noun of sâyidan, variants sâbidan "to bruise, file," pasâvidan "to touch;" Khotanese sauy- "to rub;" Sogdian ps'w- "to touch;" Proto-Iranian *sau- "to rub."


Fr.: Errai   

Same as → Gamma Cephei.

From Ar. ar-râ'i (الراعی) "the shepherd."

  ایرنگ، خطا   
irang (#), xatâ (#)

Fr.: erreur   

1) A deviation from accuracy or correctness; a mistake.
2) Physics: The difference between the calculated or observed value and the true value of a quantity. See also:
absolute error, → bias error, → calibration error, → cascade error, → error bar, → fitting error, → instrument error, → observational error, → probable error (PE), → random error, → relative error, → root-mean-square error, → sampling error, → standard error, → systematic error, → Type I error, → Type II error.

From O.Fr. erreur, from L. errorem (nom. error) "a wandering, straying, mistake," from errare "to wander."

Irang, from Mid.Pers. êrang "error, mistake;" xatâ, from Ar.

error bar
  بند ِ ایرنگ، ~ خطا   
band-e irang, ~ xatâ

Fr.: barre d'erreur   

On a graph displaying the results of a measurement, the dash used to indicate the confidence range of the value attributed to a quantity.

error; bar, from O.Fr. barre, from V.L. *barra "bar, barrier," or perhaps from Gaulish *barro "summit."

Band "that which closes, shuts, blocks," from bastan, band- "to shut, bind," from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie" (cf. Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind;" Ger. binden; E. bind); → error.


Fr.: entrer en éruption   

To burst forth; to eject matter (of a star, volcano, geyser, etc.). → eruptive variable.

From L eruptus "burst forth, broken out," p.p. of erumpere "to break out, burst forth," from → ex- "out" + rumpere "to break, rupture."

Osdaridan, from os-, → ex- + daridan "to tear, rend, lacerate;" Mid.Pers. darridan "to tear, split;" Av. dar- "to tear," dərəta- "cut," auua.dərənant- "shattering;" cf. Skt. dar- "to crack, split, break, burst," darati "he splits;" Gk. derein "to flay," derma "skin;" P.Gmc. *teran; O.E. teran; E. tear; Ger. zerren "to pull, to tear," zehren "to undermine, to wear out;" PIE base *der- " to split, peel, flay."


Fr.: éruption   

1) An act, process, or instance of erupting; something that is erupted or ejected.
2) → flare.
3) Geology: The ejection of molten rock, steam, etc., as from a volcano or geyser.

Verbal noun of → erupt.


Fr.: éruptif   

Relating to, formed by, characterized by, or producing → eruption.

eruption; → -ive.

eruptive object
  بر‌آخت ِ اسدرشی   
barÂxt-e osdareši

Fr.: objet éruptif   

An astronomical object such as a → variable star, a → nova, a → young stellar object, etc. characterized by abrupt changes of luminosity.

eruptive; → object.

eruptive prominence
  زبانه‌ی ِ اسدرشی   
zabâne-ye osdareši

Fr.: protubérance éruptive   

A huge solar prominence which has previously been quiescent but suddenly starts to lift up from the → photosphere with velocities of several hundred km/s and escapes into the → interplanetary space. Eruptive prominences with the highest velocities have been observed at 1300 km/s, reaching heights of 1 million km above the photosphere. Such prominences are often observed at the solar limb, in association with → coronal mass ejections. On the Sun's disk, the equivalent phenomenon is an eruptive filament.

eruptive; → prominence

eruptive variable
  ورتنده‌ی ِ اسدرشی   
vartande-ye osdareši

Fr.: variable éruptive   

same as → cataclysmic variable.

eruptive; → variable.

  ۱) گریختن، ۲) گریز   
1) gorixtan, 2) goriz (#)

Fr.: 1) échapper, s'échapper; 2) échapement   

1) To get away; to get free of.
2) An act or instance of escaping.

From M.E. escapen; O.Fr. eschaper, from V.L. *excappare, literally "to get out of one's cape, leave a pursuer with just one's cape," from L. → ex- "out" + L.L. cappa "mantle."

Gorixtan, goriz- "to escape; to flee, run away;" Mid.Pers. virextan; Proto-Iranian *vi-raik, from vi- "apart, asunder" + *raik; Av. raek- "to leave, set free, let off;" Mid./Mod.Pers. reg/rig (in mordé-rig "inheritance"); Skt. ric- "to leave," rinakti "gives up, evacuates;" Gk. leipein "to leave;" L. linquere "to leave;" from PIE *linkw-, from *leikw- "to leave behind" (cf. Goth. leihvan; O.E. lænan "to lend;" O.H.G. lihan "to borrow;" O.N. lan "loan").

escape velocity
  تندای ِ گریز   
tondâ-ye goriz

Fr.: vitesse d'échapement   

The speed an object must attain in order to free itself from the gravitational influence of an astronomical body. It is the minimum velocity for the object to enter a parabolic trajectory. The escape velocity is given by: Ve = (2GM/r)1/2, where G is the → gravitational constant, M is the mass of the astronomical body, and r is its radius. The escape velocity of the Earth is about 11.2 km s-1, that of the Moon is 2.4 km s-1, and that of the Sun about 618 km s-1.

escape; → velocity.


Fr.: ESPaDOnS   

An advanced stellar → spectropolarimeter designed and built at the Observatoire Midi-Pyréenées and installed at the → Canada-France-Hawaii Telescope (CFHT). It can obtain a a complete optical spectrum, from 370 nm to 1050 nm, in a single exposure. Among its characteristics: resolving power 65 000 to 80 000; 12% peak throughput (telescope and detector included); continuum subtracted linear and circular polarization spectra of the stellar light (in polarimetric mode). ESPaDOnS is used to study a broad range of important problems in stellar physics: from → stellar magnetic fields to → accretion disks and → extrasolar planets; from inhomogeneities and differential rotation on stellar surfaces to activity cycles and magnetic braking; from microscopic diffusion to turbulence, convection, and circulation in stellar interiors; from abundances and pulsations in stellar atmospheres to stellar winds; from the early phases of stellar formation to the late stages of stellar evolution; from extended circumstellar environments to distant interstellar medium (Donati et al., 2006, Solar Polarization, ASP Conf. Series, 358, 362, eds. R. Casini, B. W. Lites).

Short for Echelle Spectro-Polarimetric Device for the O bservation of Stars; → echelle; → spectro-; → polarimetric; → device; → observation; → star.

  نشاختن، نشازیدن   
nešâxtan, nešâzidan

Fr.: établir   

1) To found, institute, build, or bring into being on a firm or stable basis.
2) To show to be valid or true; prove.

From O.Fr. establiss-, stem of establir, from L. stabilire "make stable," from stabilis "firm, stable," literally "able to stand," from stare "to stand;" PIE base *sta- "to stand" (cf. Mod.Pers. istâdan "to stand;" O.Pers./Av. sta- "to stand, stand still; set;" Skt. sthâ- "to stand;" Gk. histemi "put, place, weigh;" stasis "a standing still;" Lith. statau "place;" Goth. standan; O.E. standan "to stand," stede "place").

Nešâxtan, nešâzidan "to establish; to fix in the ground, strengthen," from ne- "down, below," → ni-, + šâxtan, šâz-, variants of Mod./Mid.Pers. sâxtan, sâz- "to form, prepare, build, make," ultimately from Proto-Iranian *sac- "to fit, be suitable; to prepare."


Fr.: 1, 2, 3, 4) établissement; 4) les pouvoirs établis   

1) The act or an instance of establishing.
2) The state or fact of being established.
3) Something established; a constituted order or system.
4) (often initial capital letter) The existing power structure in society; the dominant groups in society and their customs or institutions (

establish; → -ment.

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