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
astronomical site
  سیت ِ اخترشناسیک، ~ اخترشناختی   
sit-e axtaršenâsik, ~ axtaršenâxti

Fr.: site astronomique   

A certain place whose characteristics, as to location, altitude, atmospheric conditions, etc., make it appropriate for astronomical observations.

astronomical; → site.

astronomical table
  جدول ِ اختری   
jadval-e axtari

Fr.: table astronomique   

One of a set of tables giving parameters used for calculations of positions of the Sun, the Moon, and the planets in particular in pre-telescopic astronomy. The oldest known astronomical tables are those of Ptolemy. In Modern astronomy it is usually replaced by the term → ephemeris. Same as → zij. See also → Toledan Tables, → Alfonsine Tables.

astronomical; → table.

astronomical twilight
  نیمتاب ِ اخترشناسیک، ~ اخترشناختی   
nimtâb-e axtaršenâsik, ~ axtarsnâxti

Fr.: crépuscule astronomique   

The time between sunset or sunrise and the moment when the Sun's center lies 18° below the horizon. → civil twilight.

astronomical; → twilight.

astronomical unit (au)
  یکا‌ی ِ اخترشناسیک، ~ اخترشناختی   
yekâ-ye axtaršenâsik, ~ axtaršenâxti (#)

Fr.: unité astronomique   

1) A unit of length equal to 149 597 870 700 m exactly, with symbol "au" (re-definition at the International Astronomical Union's 28th General Assembly in Beijing, China, August 20-31). The astronomical unit equals 1.5813 × 10-5 → light-years and 4.8481 ×10-6 → parsecs.
2) Previous definition: The radius of a circular orbit in which a body of negligible mass, and free of perturbations, would revolve around the Sun in 2 π / k days, where k is the → Gaussian gravitational constant. This is slightly less than the semi-major axis of the Earth's orbit.

astronomical; → unit.

astronomy
  اخترشناسی   
axtaršenâsi (#)

Fr.: astronomie   

The science of the celestial bodies and the Universe, dealing especially with the positions, dimensions, distribution, motion, chemical composition, energy, and evolution of celestial bodies and phenomena.

O.Fr. astronomie, from L. astronomia, from Gk. astronomia, from → astro- "star" + nomos "arranging, regulating," related to nemein "to deal out."

Axtaršenâsi, from axtar "star," → astro- + -šenâsi "knowledge" from šenâxtan "to know, to discern."

astroparticle physics
  فیزیک ِ اخترذره   
fizik-e axtar-šzarre

Fr.: physique des astroparicules   

The area of science which deals with → elementary particle and → high-energy phenomena in → astrophysics and → cosmology.

astro-; → particle; → physics.

astrophotography
  اختر‌شیدنگاری، شیدنگاری ِ اختری   
axtar-šidnegâri, šidnegâri-ye axtari

Fr.: astrophotographie   

The photography of stars, other celestial bodies, and stellar fields.

astro-, → photography.

astrophotometry
  اخترشیدسنجی، شیدسنجی ِ اختری   
axtar-šidsanji, šidsanji-ye axtari

Fr.: astrophotométrie   

The measurement of the intensity of light of celestial bodies.

Astrophotometry, from → astro- + → photometry.

Axtar-šidsanji, from axtar-, → astro-, + -šidsanji, → photometry.

astrophysical
  اخترفیزیکی   
axtarfiziki (#)

Fr.: astrophysiqie   

Of or pertaining to → astrophysics.

astrophysics + → -al

astrophysical jet
  شان ِ اخترفیزیکی   
šân-e axtarfiziki

Fr.: jet astrophysique   

A very fast moving, → collimated beam of → ionized gas at high temperatures associated with → protostars, → X-ray binary systems, and, at a larger scale, with → active galactic nuclei.

astrophysical; → jet.

astrophysical object
  بر‌آخت ِ اخترفیزیکی   
barâxt-e axtarfiziki

Fr.: objet astrophysique   

An extraterrestrial → object whose physical properties and formation are studied in → astrophysics.

astrophysical; → object.

astrophysicist
  اخترفیزیکدان   
axtarfizikdân (#)

Fr.: astrophysicien   

A scientist who studies → astrophysics.

astro-; → physicist. The term astrophysicist was introduced by Greenwich astronomer Edwin Dunkin in 1869.

astrophysics
  اخترفیزیک   
axtarfizik (#)

Fr.: astrophysique   

The branch of → astronomy that deals with the → physics of → celestial objects and the → Universe in general. It relies on the assumption that the → laws of physics apply everywhere in the Universe and throughout all time. See also → observational astrophysics, → theoretical astrophysics.

Astrophysics, from → astro- "star" + → physics. The first use of the term astrophysics has been attributed to Johann Karl Friedrich Zöllner (1834-1882) in 1865. He defined it as a coalescence of physics and chemistry with astronomy (History of Astronomy: An Encyclopedia, ed. John Lankford, Routledge, 1997).

asymmetric, asymmetrical
  ناهمامون   
nâhamâmun

Fr.: asymétrique   

Not having → symmetry.

asymmetry.

asymmetry
  ناهمامونی   
nâhamâmuni

Fr.: asymétrie   

Lack of symmetry; not symmetrical.

Gk. asymmetria "lack of proportion," from asymmetros "ill-proportioned," from → a- "not" + symmetros "commensurable, symmetrical."

Nâhamâmuni, from nâ- "not" + hamâmuni "symmetry," from ham- "together = syn" + -â-, euphonic affix, + mun "measure" + -i, noun affix.

asymptote
  ناهمساو   
nâhamsâv

Fr.: asymptote   

A straight line which is approached, but never reached, by an infinite branch of a curve, and which can be regarded as a line tangent to the curve at infinity.

Gk. asymptotos "not falling together," from → a- "not" + → syn "with" + ptotos "fallen," verbal adj. from piptein "to fall".

Nâhamsâv, literally "not touching each other," from nâ- "not" + ham "with" (akin to Gk. syn-) + sâv, agent noun of sâvidan "to touch."

asymptotic
  ناهمساوی   
nâhamsâvi

Fr.: asymptotique   

Of or pertaining to an → asymptote.

Adjective from → asymptote; → -ic.

asymptotic freedom
  آزادی ِ ناهمساوی   
âzâdi-ye nâhamsâvi

Fr.: liberté asymptotique   

The phenomenon wherein the → quarks within a → hadron get closer together, the force of containment gets weaker so that it asymptotically approaches zero for close confinement. According to → quantum chromodynamics, the quarks in close confinement are completely free to move about. On the contrary, the further we try to force the quarks apart, the greater the force of containment. The 2004 Nobel Prize in Physics was awarded to David Gross, Frank Wilczek, and David Politzer for their discovery of asymptotic freedom. This discovery established quantum chromodynamics as the correct theory of the → strong interaction.

asymptotic; → freedom.

asymptotic giant branch (AGB)
  شاخه‌ی ِ ناهمساوی ِ غولان   
šâxe-ye nâhamsâvi-ye qulân

Fr.: branche asymptotique des géantes   

A region of the → Hertzsprung-Russell diagram populated by evolving → low-mass to → intermediate-mass stars. These stars have an electron → degenerate core of carbon and oxygen surrounded by two burning shells of helium and hydrogen. The H and He-burning shells are activated alternately in the deep layers of the star. An extended and tenuous convection envelope, having a radius of 104-105 times the size of the core, lies above these shells. The loosely bound envelope is gradually eroded by the strong → stellar wind, which forms a dusty → circumstellar envelope out to several hundreds of stellar radii. The convective envelope, stellar atmosphere, and circumstellar envelope have a rich and changing chemical composition provided by → nucleosynthesis processes in the burning shells in the deep interior.

symptotic; → giant; → branch.

asymptotic velocity
  تندای ِ ناهمساوی   
tondâ-ye nâhamsâvi

Fr.: vitesse asymptotique   

For → stellar winds, same as → terminal velocity.

asymptotic; → velocity.

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