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: 912
ansa
  دستک   
dastak

Fr.: anse   

Plural form: ansae.
1) The "handles," or extremities, of → Saturn's rings as viewed from Earth.
2) The extremities of a → lenticular galaxy.

L. ansa "handle."

Dastak "handle," from dast "hand" (Mid.Pers. dast; O.Pers. dasta-; Av. zasta-; cf. Skt. hásta-; Gk. kheir; L. praesto "at hand;" Arm. jern "hand;" Lith. pa-žastis "arm-pit;" PIE *ghes-to-) + -ak suffix denoting relation, affinity, similarity.

ansatz
  آنزاتس   
ânzâts

Fr.: ansatz   

In physics and mathematics an a priori assumption that is used to establish the form of an equation or a system of equations. The ansatz, which is verified later by the result, is meant to facilitate the solution. → Bethe ansatz.

From Ger. Ansatz "attempt, approach, beginning."

antapex
  پادچکاد   
pâdcakâd

Fr.: antiapex   

The direction in the sky (in → Columba) away from which the Sun seems to be moving (at a speed of 19.4 km/s) relative to general field stars in the Galaxy.

Antapex from L. ant-, → anti- "against, opposite," + L. → apex "summit, peak, tip."

Pâdcakâd from pâd-, → anti- + cakâd "summit of a mountain; top, crown of the head, top of the forehead," from Mid.Pers. cakât "summit," → apex.

Antarctic
  دشترگان، جنوبگان   
Daštargân, Jonubgân (#)

Fr.: Antarctique   

The south polar area, south of latitude 66° 33' 8'' S.

Antarctic, from O.Fr. antartique, from M.L. antarcticus, from Gk. antarktikos "opposite the north," from → anti- "opposite" + arktikos, → arctic.

Daštargân, from daštar, → south, + -gân suffix indicating the direction.
Jonubgân, from jonub "south," from Ar. janub "south," + -gân, as above.

Antares (α Scorpii)
  کژدمدل، قلب‌العقرب   
Každom-del, Qalb-ol-Aqrab

Fr.: Antarès   

A → red supergiant star (→ spectral type M1 Ib) in the constellation → Scorpius, lying about 500 → light-years (170 (+35/-25) → parsecs) from Earth. It has a dwarf massive companion (B3 V), which is a → radio source.

Antares, in Gk. "rival of Mars," from Gk. → anti + Ares "the Gk. god of War, called Mars by the Romans." The comparison with the planet Mars is because they are both red in color and have the same brightness.

Každom-del "the heart of the Scorpion," from každom "scorpion" + del, → heart. Qalb-ol-'Aqrab "the heart of the Scorpion," from Ar. Qalb "heart" + 'aqrab "scorpion".

antecedent
  پیشای، پیش‌آی   
pišây

Fr.: antécédent   

Logic: In a → conditional proposition, the → clause which follows if.

M.E., from from L. antecedentem, from antecedere "go before, precede," from ante- "before" + cedere "to yield, to go," → process.

Pišây, from piš "before," → pre-, + ây present stem of âmadan "to come," → process.

antenna
  آنتن   
ânten

Fr.: antenne   

1) General: A device or a set of wires that receives or sends out radio signals.
2) In radio astronomy, the major dish-like component or wired structure used to collect radio signals.

L. antenna "sail yard," the long yard that sticks up on some sails, of unknown origin, perhaps from PIE base *temp- "to stretch, extend." In this sense, it is a translation of Gk. keraiai "horns" (of insects).

Âten, from Fr. antenne, from L. as above.

antenna gain
  بهره‌ی ِ آنتن   
bahre-ye ânten

Fr.: gain d'antenne   

A measure of the directivity of a radio telescope. It is the ratio of the amount of power received in the direction the dish is pointing to the smaller amount of power from other directions in the sidelobes.

antenna; → gain.

antenna lobe
  لپ ِ آنتن   
lap-e ânten

Fr.: lobe d'antenne   

A three-dimensional section of the → radiation pattern ofa directional antenna, bounded by one or more cones of nulls or by regions of diminished irradiance.

antenna; → lobe.

antenna pattern
  الگوی ِ آنتن   
olgu-ye ânten

Fr.: diagramme de rayonnement   

The response of an antenna to incident radiation as a function of the direction of incidence of the radiation. A generic antenna pattern consists of a → main lobe and a number of smaller → side lobes. Also called → radiation pattern.

antenna; → pattern.

antenna temperature
  دما‌ی ِ آنتن   
damâ-ye ânten

Fr.: température d'antenne   

In radio astronomy, a measure of the power absorbed by the antenna. In an ideal, loss-free radio telescope, the antenna temperature is equal to the brightness temperature if the intensity of the received radiation is constant within the main lobe. → antenna; → temperature.

antenna; → temperature.

Antennae galaxies
  کهکشان‌ها‌ی ِ شاخکی   
kahkešânhâ-ye šâxak

Fr.: galaxies des Antennes   

The pair of colliding galaxies NGC4038 and NGC4039 and the long arcing insect-like "antennae" of luminous matter revealed by optical telescopes. The "antennae" are believed to have been produced by the collision between the galaxies that began about 100 million years ago and is still occurring. The Antennae Galaxies, about 60 million → light-years from Earth, lie in the constellation → Corvus.

Antennae, plural of → antenna; → galaxy.

Kahkešânhâ, plural of kahkešângalaxy; šâxak "insect antenna," from šâx "horn" (Mid.Pers šâk, cf. Skt. sakha- "a branch, a limb," Arm. cax, Lit. šaka, O.S. soxa, PIE *kakhâ "branch") + -ak suffix denoting relation, affinity, similarity (as in dastak, pos(tak, pas(mak, xarak, nâxonak, mus(ak, eynak);

anthropic principle
  پروز ِ انسان-هستی   
parvaz-e ensân-hasti

Fr.: principe anthropique   

The idea that the existence of → life and, in particular, our presence as → intelligent  → observers, → constrains the nature of the → Universe. It is an attempt to explain the observed fact that the → fundamental constants of nature are just right or fine-tuned to allow the Universe and life to exist. This is not however a "principle." See also → weak anthropic principle, → strong anthropic principle. Compare → Copernican principle.

Anthropic, from Gk. anthropikos "human," from anthropos "human being, man," → anthropo-; → principle.

Parvaz, → principle; ensân-hasti, from ensân, → anthropo-, + Mod.Pers. hasti "existence, being," Mid.Pers. astih, O.Pers. astiy; Av. asti "is," O.Pers./Av. root ah- "to be;" cf. Skt. as-; Gk. esti; L. est; PIE *es-.

anthropo-
  انسان-   
ensân- (#)

Fr.: anthropo-   

A prefix with the meaning of "pertaining to man or human beings." Before a vowel, anthrop-. See also → man, → human. → anthropic principle.

Frpm Gk. anthropos "man, human being," from aner "man" (as opposed to a woman, a god, or a boy), from PIE *hner "man;" cf. Pers. nar "male," Skt. nara-, Welsh ner "man."

Ensân-, from ensân "mankind," loan from Ar. insân.

anti-, ant-
  پاد-   
pâd- (#)

Fr.: anti-, ant-   

Prefix meaning "against, opposite of;" e.g. in → anticenter; → anticorrelation; → anticyclone; → antiparticle.

L. anti- from Gk. anti "against, opposite, instead of," from PIE *anti "against".

Pâd- "agaist, contrary to," from Mid.Pers. pât- "to, at, for, in," from O.Pers. paity "agaist, back, opposite to, toward, face to face, in front of;" Av. paiti; cf. Skt. práti "toward, against, again, back, in return, opposite;" Pali pati-; Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti.

antibaryon
  پادباریون   
pâdbâriyon

Fr.: antibaryon   

The → antiparticle of a → baryon.

anti-; → baryon.

anticenter
  پادمرکز   
pâdmarkaz

Fr.: anticentre   

The point in the → Galactic plane that lies directly opposite the → Galactic center. It lies in → Auriga at approximately R.A. 5h 46m, Dec. +28° 56'; the nearest bright star to it is → Alnath in → Taurus.

Anticenter, from → anti- + → center.

Pâdmarkaz, from pâd-, → anti-, + markaz, → center.

anticorona
  پاد‌افسر، شکوه   
pâdafsar, šokuh

Fr.: gloire   

Meteorology: Small, faintly colored rings of light surrounding the → antisolar point, seen when looking down at a water cloud. Same as glory.

Anticorona, from → anti- + → corona.

Pâdafsar, from pâd-, → anti- + afsar "corona."
Šokuh "glory."

anticorrelation
  پادهم‌باز‌آنش   
pâdhambâzâneš

Fr.: anticorrelation   

Statistics: The correlation coefficient of two random variables X and Y is in general defined as the ratio of the Cov(X,Y) to the two standard deviations of X and Y. It varies between 1 and -1 corresponding to complete correlation or anticorrelation.

Anticorrelation, from → anti- + → correlation.

Pâdhambâzâneš, from pâd-, → anti-, + hambâzâneš, → correlation.

anticrepuscular rays
  پرتوهای ِ پاد نیمتابی   
partowhâ-ye pâdnimtâbi

Fr.: rayons anticrépusculaires   

Rays of → sunlight that appear to converge at the → antisolar point. Like → crepuscular rays, they are parallel beams of sunlight from holes in the clouds, and their apparently odd directions are a perspective effect.

anti-; → crepuscular rays.

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