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: 482
bias voltage
  ولتاژ ِ ورک   
voltâž-e varak

Fr.: voltage de biais   

A voltage applied or developed between two electrodes as a bias.

bias; → voltage.

biased
  ورکدار   
varakdâr

Fr.: biaisé   

Marked by or exhibiting bias; characterized by settled and often prejudiced outlook.

Biased, from → bias + adj. suffix -ed.

Varakdâr, from varak, → bias + -dâr "possessing, having," from dâštan "to possess, to have."

biased estimate
  بر‌آورد ِ ورکدار   
barâvard-e varakdâr

Fr.: estimation biasiée   

Of a population parameter, if the mean or expectation of the statistics is not equal to the parameter.

biased; → estimate.

barâvard, → estimate; varakdârbiased.

biased galaxy formation
  دیسش ِ ورکدار ِ کهکشانها   
diseš-e varakdâr-e kahkašânhâ

Fr.: formation biaisée de galaxies   

The theory that bright galaxies form preferentially from anomalously overdense perturbations in the → early Universe.

biased; → galaxy; → formation.

biased sample
  نمونان ِ ورکدار   
nemunân-e varakdâr

Fr.: échantillon biaisé   

A sample that is not a true representative of a → statistical population to which generalizations are to be made. A sample which is not → randomly constituted.

biased; → sample.

biased statistics
  آمار ِ ورکدار   
âmâr-e varakdâr

Fr.: statistique biasée   

A statistics based on a → biased sample.

biased; → statistics.

biaxial crystal
  بلور ِ دو‌آسه   
bolur-e doâsé

Fr.: cristal biaxe   

A birefrigent crystal, such as mica, that is characterized by having two optical axes along which light is propagated with equal velocities.

Biaxial, from → bi- "two" + axial, from → axe; → crystal.

BICEP2
     
BICEP2

Fr.: BICEP2   

A → microwave → polarimeter designed specifically to target the → B-mode signature of → inflation in the → cosmic microwave background polarization. BICEP2 observed from the South Pole for three seasons from 2010 to 2012. This 26 cm aperture → telescope comprised an all-cold refracting optical system equipped with a → bolometer array of 512 → detectors (256 pixels) operating at 150 GHz.

BICEP2, the upgraded version of the first BICEP, short for Background Imaging of Cosmic Extragalactic Polarization.

biconcave lens
  عدسی ِ دوکاو   
adasi-ye dokâv

Fr.: lentille biconcave   

Describing a lens with two concave faces.

Biconcave, from → bi- + → concave; → lens.

Adasi, → lens; dokâv "biconcave," from do-, → bi- + kâv, → concave.

biconvex lens
  عدسی ِ دوکوژ   
adasi-ye dokuž

Fr.: lentille biconvexe   

A spherical lens with two convex faces. The radii of curvature for the two surfaces may or may not be the same.

Biconvex, from → bi- + → convex; → lens.

Adasi, → lens; dokuž "biconvex" from do-, → bi- + kuž, → convex.

Biela's comet
  دنباله‌دار ِ بیلا   
donbâledâr-e Biyelâ

Fr.: comète de Biela   

A comet having a short period of 6.62 years discovered by Biela. It broke up on its 1846 return and subsequently gave rise to a spectacular meteor shower.

In honor of Wilhelm von Biela (1782-1856), Austrian military officer and amateur astronomer, who re-discovered the comet Biela in 1826, although it had been seen first in 1772. → comet.

Bielids
  بیلاییان   
Bielâyiân

Fr.: Bielides   

A → meteor shower, originating from → Biela's comet, whose → radiant lies in the constellation → Andromeda; also called → Andromidids.

Bielids, From Biel(a) + → -ids suffix denoting "descendant of, belonging to the family of."

bifurcate
  ۱) دوگلیدن؛ ۲) دوگل   
1) dogalidan; 2) dogal

Fr.: 1) bifurquer; 2) à deux branches   

1) To divide into two branches.
2) Divided into two branches.

M.L. bifurcatus, from L. → bi- "two," + furca "pitchfork; fork used in cooking," of uncertain origin.

Dogalidan, from Gilaki dogal "fork, two-branched," cf. Tabari dekal, dokkal, doqâla, from do, → two, + gal, kal "branch, part," cf. Kurd. (Kurmanji) kar "part, piece," cognate with Pers. kârd "knife," (+ *niš-) nišgarda "cobbler's knife;" Mid.Pers. kârt "knife," karēnītan, karītan "to cut," (+ *fra-) fragard "chapter, section;" Av. karət- "to cut;" Proto-Iranian *kart- "to cut;" cf. Skt. kart- "to cut;" Gk. karpos "fruit;" L. carpere "to cut, divide, pluck;" PIE base *(s)ker- "to cut;" + -idan infinitive suffix. See also → shear.

bifurcation
  دوگلش   
dogaleš

Fr.: bifurcation   

1) A branching or division into two parts; a splitting apart.
2) A sudden qualitative change in the behavior of a → dynamical system. The equation describing the evolution of the system finds several solutions for certain values of a parameter. Systems undergoing a bifurcation do not necessarily return to their original state, even if the parameter returns to its nominal value. See also → chaos.

Verbal noun of → bifurcate.

bifurcation point
  نقطه‌ی ِ دوگلش   
noqte-ye dogaleš

Fr.: point de bifurcation   

The point or moment in the evolution of a → dynamical system that occurs if a parameter passes through a critical point. At this point the system branches into any number of qualitatively new types of behavior.

bifurcation; → point.

bifurcation theory
  نگره‌ی ِ دوگلش   
negare-ye dogaleš

Fr.: théorie de bifurcation   

1) A theory which studies how, in certain nonlinear systems, there may be paths and shifts in behavior dependent on small changes in circumstances or the current position of the system.
2) Math.: The study of the behavior of a solution of a nonlinear problem in the neighborhood of a known solution, particularly as a parameter varies.

bifurcation; → theory.

big
  بزرگ، مه   
bozorg (#), meh (#)

Fr.: grand, gros   

Of considerable size, number, quantity, large.

M.E., northern England dialect, of unknown origin.

Bozorg, → large. Meh "great, large;" Mid.Pers. meh, mas; Av. maz-, masan-, mazant- "great, important," mazan- "greatness, majesty," mazišta- "greatest;" cf. Skt. mah-, mahant-; Gk. megas; L. magnus; PIE *meg- "great."

Big Bang
  مه بانگ، بیگ بنگ   
Meh Bâng (#), Big Bang (#)

Fr.: Big Bang   

A theory which states that the Universe came into existence in an "instantaneous" event some 14 billion years ago. Matter was created in that initial event and as time has gone by the Universe has expanded and the contents evolved into the galaxies and stars and of today. The Big Bang is sometimes described as an "explosion." However, matter and energy did not erupt into a pre-existing space, since they came into being simultaneously with space and time.

big; bang "a sudden loud noise, as of an explosion" (probably of Scandinavian origin; akin to Icelandic banga "to hammer"). The term was coined by Fred Hoyle in 1950 in the course of discussions entitled "the Nature of the Universe" broadcasted by BBC. Hoyle's intention was a pejorative term in order to ridicule the theory which his own → steady-state theory contested.

Meh Bâng, from meh "great, large," → big, + bâng "voice, sound, clamour," (Mid.Pers. vâng, Av. vaocanghê "to declare (by means of speech"), vacah- "word," from vac- "to speak, say," cf. Mod.Pers. vâžé "word," âvâz "voice, sound, song," Skt. vakti "speaks, says," vacas- "word;" Gk. epos "word," L. vox "voice;" PIE base *wek- "to speak").

Big Bang model
  مدل ِ مه بانگ، ~ بیگ بنگ   
model-e Meh Bâng, ~ Big Bang

Fr.: modèle du big bang   

Big Bang; → model.

Big Bang nucleosynthesis (BBN)
  هسته‌هندایش ِ مهبانگ، ~ بیگ بنگ   
haste-handâyeš-e Meh Bâng, ~ Big Bang

Fr.: nucléosynthèse de Big Bang   

The production of → light elements, roughly three minutes after the → Big Bang when the temperature of the → Universe dropped from 1032 K to approximately 109 K. In a short time interval → protons and → neutrons collided to produce → deuterium. Most of the deuterium then fused with other protons and neutrons to produce → helium and a small amount of → tritium. The element → lithium 7 could also arise form the coalescence of one tritium and two deuterium nuclei. According to the Big Bang nucleosynthesis theory, roughly 25% of the mass of the Universe consists of helium. It also predicts about 0.01% deuterium, and even smaller quantities of lithium. These predictions depend critically on the → baryon-photon ratio. Same as → primordial nucleosynthesis.

Big Bang; → nucleosynthesis.

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