An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 639
ecliptic pole
  قطب ِ هورپهی   
qotb-e hurpehi

Fr.: pole de l'écliptique   

Either of the two points on the celestial sphere that are 90° above and below the plane of ecliptic. The north ecliptic pole lies in → Draco, and the south ecliptic pole in → Dorado. Due to → precession, the → celestial pole moves in a circle around the ecliptic poles once every 25,800 years.

ecliptic, → pole.

ecliptic system
  راژمان ِ هورپهی   
râžmân-e hurpehi

Fr.: système écliptique   

Coordinate system with the ecliptic as the fundamental plane.

ecliptic; → system.

eco-
  بوم-   
bum- (#)

Fr.: éco-   

A combining form meaning "house, household, environment, nature, natural habitat."

Ultimately from Gk. oikos "house," cognate with L. villa "country house, farm," related to vicus "village, group of houses; " cf. Av. vis- "homestead, community;" O.Pers. viθ- "house, royal house, farm;" Mid.Pers. wis "village;" dialectal Pers. wiš-, vīš- "to set (of Sun)," wīs- "to enter" (Cheung 2007); Skt. viś- "settlement, house, tribe, people;" Goth. weihs "village;" Lith. viešpats "master of the house;" PIE *ueik'- "to settle (down)."

Bum-, from bum "region, land, a mansion or place where one dwells in saftey; nature, disposition;" Mid.Pers. bûm "land, earth, country;" O.Pers. būmi- "place of being/living, land, region;" Av. būmī- "earth," from bav- "to be, become, take place;" cf. Skt. bhūmi- "land, region;" PIE *bheu- "to be, come into being, become" (cf. Gk. phu- "become," phuein "to bring forth, make grow;" L. fui "I was" (perf. tense of esse), futurus "that is to be, future;" Ger. present first and second person sing. bin, bist; E. to be; O.Ir. bi'u "I am;" Lith. bu'ti "to be;" Rus. byt' "to be").

ecology
  بوم‌شناسی   
bumšenâsi (#)

Fr.: écologie   

1) The scientific discipline that is concerned with the relationships between living organisms and their past, present, and future environments.
2) The study of the damaging effects of modern civilisation on the environment, with the aim of prevention or reversal through conservation.

eco- + → -logy.

economic
  بومداتی   
bumdâti

Fr.: économique   

1) Pertaining to the production, distribution, and use of income, wealth, and commodities.
2) Of or relating to the science of economics.
3) Pertaining to an economy, or system of organization or operation, especially of the process of production (Dictionary.com).

Adjective, from → economics.

economic growth
  رست ِ بومداتی   
rost-e bumdâti

Fr.: croissance économique   

An increase in the output that an economy produces over a period of time.

economic; → growth.

economical
  بومداتی   
bumdâti

Fr.: économique   

1) Avoiding waste or extravagance; thrifty.
2) → economic.

economic; → -al.

economics
  بومداتیک   
bumdâtik

Fr.: économie   

The science that deals with description and analysis of the production, distribution, and consumption of goods and services.

From L. oeconomicus "well ordered," from Gk. oikonomikos "practiced in the management of a household or family," from oikonomia, from oiko- "house," → eco-, + -nomia "rule, law," → -nomy; + → -ics.

Bum, → eco- + -dât, → -nomy, + -ik, → -ics.

economize
  بومداتیدن   
bumdâtidan

Fr.: économiser   

1) To practice economy; avoid waste or extravagance.
2) To manage economically; use sparingly or frugally (Dictionary.com).

From econom(y), → economy, + → -ize.

economy
  بومدات   
bumdât

Fr.: économie   

1) Thrifty and efficient use of material resources of a community, society, or household; frugality in expenditures.
2) An act or means of thrifty saving; a saving.
3) The management of the resources of a community, country, etc., especially with a view to its productivity (Dictionary.com).

From M.Fr. economie, → economics.

Bumdât, back formation from bumdâti, → economic.

ecopoiesis
  بوم‌آفرینی   
bum-âfarini

Fr.: ecopoïèse   

The fabrication of a stable, enduring → ecosystem on a lifeless planet. It is the last stage of a → terraforming process.

From → eco- "house, dwelling place," + poiesis a combining form meaning "making, formation; poetry," from Gk. poesy, from poiein "to make, compose." Coined by Robert Hall Haynes (1931-1998), a Canadian geneticist and biophysicist.

Bum-âfarini, literally "creating environment," from bum "region, land," → eco- + âfarini "creation," from âfaridan, âfarin- "to create," from Mid.Pers. âfridan, âfrin- "to praise, bless; create," ultimately from Proto-Iranian āfrīta-, from prefixed frī- "to praise; to like;" cf. Av. frāy- "to satisfy, propitiate, pray;" Skt. prī- "to gladden, show favor to," prīta- "glad;" Gk. praus "gentle."

ecosphere
  بوم‌سپهر   
bumsepehr (#)

Fr.: écosphère   

The space around a star in which a planet would experience external conditions that are not incompatible with the existence of life.

Ecosphere, from eco-, → ecology, + → sphere.

Bumsepehr, from bum "eco-," → ecology, + sepehr, → sphere.

ecosystem
  بوم راژمان   
bumrâžmân

Fr.: écosystème   

Any geographic area that includes all of the organisms and nonliving parts of their physical environment.

ecology; → system.

Eddington limit
  حد ِ ادینگتون   
hadd-e Eddington (#)

Fr.: limite d'Eddington   

The theoretical upper limit of → luminosity at which the → radiation pressure of a light-emitting body would exceed the body's → gravitational attraction. A star emitting radiation at greater than the Eddington limit would break up. The Eddington luminosity for a non-rotating star is expressed as: LEdd = 4πGMmpcσT-1, where G is the → gravitational constant, M the star mass, mp the → proton mass, c the → speed of light, and σT the → Thomson cross section. It can also be written as LEdd = 4πGMcκ-1, where κ is the → opacity. In terms of solar mass, the Eddington limit can be expressed by: LEdd = 1.26 × 1038 (M/Msun) erg s-1. See also → rotational Eddington limit.

Named after Arthur Stanley Eddington (1882-1944), prominent British astrophysicist; → limit.

Eddington luminosity
  تابندگی ِ ادینگتون   
tâbandegi-ye Eddington

Fr.: luminosité d'Eddington   

Same as → Eddington limit.

Eddington limit; → luminosity.

Eddington parameter
  پارامون ِ ادینگتون   
pârâmun-e Eddington

Fr.: paramètre d'Eddington   

A → dimensionless parameter indicating the degree to which a star is close to the → Eddington limit. It is expressed as Γ = L / LEdd = κ L / (4πGMc), where L and M are the star luminosity and mass respectively, κ is the opacity, c the speed of light, and G the → gravitational constant. At the Eddington limit, Γ = 1, the star would become unbound. Because stellar luminosity generally scales with a high power of the stellar mass (LM3-4), → massive stars with M larger than 10 Msun generally have electron Eddington parameters of order Γ ≅ 0.1-1.

After Arthur Stanley Eddington (1882-1944), prominent British astrophysicist; → parameter.

Eddington-Lemaître Universe
  گیتی ِ ادینگتون-لومتر   
giti-ye Eddington-Lemaître (#)

Fr.: Univers d'Eddington-Lemaître   

A theoretical model in which the → cosmological constant plays a crucial role by allowing an initial phase that is identical to the Einstein static Universe. After an arbitrarily long time, the Universe begins to expand. The difficulty with this model is that the initiation of galaxy formation may actually cause a collapse rather than initiate an → expansion of the Universe.

Eddington limit; Lemaître in honor of Georges-Henri Lemaître (1894-1966), a Belgian Roman Catholic priest, who first proposed the Big Bang theory; → universe.

Eddington-Sweet time scale
  مرپل ِ زمانی ِ ادینگتون-سوییت   
marpel-e zamâni-ye Eddington-Sweet

Fr.: échelle de temps d'Eddington-Sweet   

The time required for the redistribution of → angular momentum due to → meridional circulation. The Eddington-Sweet time for a uniformly → rotating star is expressed as: τES = τKH . GM / (Ω2 R3), where τKH is the → Kelvin-Helmholtz time scale, R, M, and L designate the radius, mass, and luminosity respectively, Ω the → angular velocity, and G the → gravitational constant. The Eddington-Sweet time scale can be approximated by τES≅ τKH / χ, where χ is the ratio of the → centrifugal force to → gravity. For the Sun, χ ≅ 10-5 resulting in an Eddington-Sweet time scale which is too long (1012 years), i.e. unimportant. In contrast, for a rotating → massive star  χ is not so much less than 1. Hence the Eddington-Sweet circulation is very important in massive stars.

Named after the prominent British astrophysicist Arthur S. Eddington (1882-1944), who was the first to suggest these currents (in The Internal Constitution of the Stars, Dover Pub. Inc., New York, 1926) and P. A. Sweet who later quantified them (1950, MNRAS 110, 548); → time scale.

eddy
  گیژاو   
gižâv

Fr.: tourbillon   

A deviation in the steady flow of a fluid causing a vortex-like motion running contrary to the general flow.
Meteo.: A small disturbance of wind in a large wind flow, which can produce turbulent conditions or turbulence.

Late M.E., from O.E. ed- "turning" + ea "water;" akin to O.N. itha.

Gižâv, from dialectical Kurd. "whirlpool," from giž "turning," Pers. gij "giddy-headed, vertigio;" Laki géž "whirlpool," vagéža "whirlwind" + âv, variant âb "water" (Mid.Pers. âb "water;" O.Pers. ap- "water;" Av. ap- "water;" cf. Skt. áp- "water;" Hitt. happa- "water;" PIE āp-, ab- "water, river;" cf. Gk. Apidanos, proper noun, a river in Thessalia; L. amnis "stream, river" (from *abnis); O.Ir. ab "river," O.Prus. ape "stream," Lith. upé "stream;" Latv. upe "brook").

eddy current
  جریان ِ فوکو   
jarayân-e Foucault (#)

Fr.: courant de Foucault   

An induced current circulating in masses of metal moving in a magnetic field or located in a changing magnetic field. Also known as → Foucault current.

eddy; → current.

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