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: 172
unstable atom
  اتم ِ ناپایدار   
atom-e nâpâydâr (#)

Fr.: atome instable   

An atom whose nuclei → decay by → radioactivity.

unstable; → atom.

unstable equilibrium
  ترازمندی ِ ناپایدار   
tarâzmandi-ye nâpâydâr

Fr.: équilibre instable   

An equilibrium state of a system in which if a small perturbation away from equilibrium is applied, the system will move farther away from equilibrium state. For example, mechanical equilibrium in which the potential energy is a maximum, as a sphere placed on top of a hill. Mathematically, if the second derivative of the energy with respect to the coordinate of interest is negative, the system is in an unstable equilibrium. → stable equilibrium.

unstable; → equilibrium.

Unukalhai
  عنق‌الحیّه   
Onoqelhayyé (#)

Fr.: Unukalhai   

The brightest star as well as the Alpha star of → Serpens, thus also known as α Serpentis. It is a third magnitude (V = 2.65) an orange giant of spectral type K2 with a radius 15 times as large as that of the Sun and a surface temperature of 4300 kelvins. It is approximately 73.2 light years from Earth. Unukalhai is in fact a triple star system. The second star (α Serpentis B) is 58 arcseconds from the primary and has a magnitude of 11.8. The third star (α Serpentis C), 13th magnitude, lies 2.3 arcminutes from A. Other designations: Cor Serpentis, HR 5854, HD 140573.

From Ar. 'unuq al-hayyah (عنق‌الحیه) "Neck of the Snake," from 'unuq "neck" + al-hayyah "snake."

up
  بالا   
bâlâ (#)

Fr.: en haut   

To, toward, or in a more elevated position.

M.E. up(pe) (adv.), O.E. up(p) "to a higher position;" cf. O.Frisian up, O.S. up, M.Du. up, op, O.N. upp; O.H.G. uf; (Ger. auf), Goth. iup.

Bâlâ "up, above, high, elevated, height" (related to boland "high," borz "height, magnitude" (it occurs also in the name of the mountain chain Alborz), Lori dialect berg "hill, mountain;" Mid.Pers. buland "high;" O.Pers. baršan- "height;" Av. barəz- "high, mount," barezan- "height;" cf. Skt. bhrant- "high;" L. fortis "strong" (Fr. & E. force); O.E. burg, burh "castle, fortified place;" Ger. Burg "castle;" Goth. baurgs "city;" E. burg, borough; Fr. bourgeois, bourgeoisie, faubourg); PIE base *bhergh- "high."

upgrade
  ۱) فراز-پداک؛ ۲) فراز-پداکیدن   
1) farâz-padâk; 2) farâz-padâkidan

Fr.: 1) rampe, montée; 2) promouvoir, revaloriser   

1a) An incline going up in the direction of movement.
1b) An increase or improvement.
1c) A new version, improved model, etc.
2a) To promote to a higher grade or rank.
2b) To improve or enhance the quality or value of (Dictionary.com).

up; → grade.

uplift
  بالامد   
bâlâmad

Fr.: surrection   

The process by which an area of Earth's crust slowly rises either due to increasing upward force applied from below or decreasing downward force (weight) from above.

From → up + → lift.

Bâlâmad, literally "coming up," from bâlâ, → up, + âmad past stem of âmadan, → come.

upload
  ۱) بارگذاشتن؛ ۲) بارگذاری   
1) bârgozâštan; 2) bârgozâri (#)

Fr.: 1) mettre en ligne; 2) mise en ligne   

To send data from one's computer to another computer. See also: → loading, → download.

up-; → load.

Bârgozâštan, literally "to put load," from bâr, → load, + gozâštan "to put, to place," → passage.

upper
  بالا، زبرین   
bâlâ (#), zabarin (#)

Fr.: supérieur   

Higher, as in place, position, pitch, or in a scale.

Upper, from → up, → hyper-.

Bâlâ, → up; zabarin, → superior.

upper arm
  بازو   
bâzu (#)

Fr.: haut du bras   

The part of the → arm between the → shoulder and the → elbow.

upper; → arm.

Bâzu "arm," from Mid.Pers. bâzûk "arm;" Av. bāzu- "arm;" Mod.Pers. bâhu "stick, staff; arm;" cf. Skt. bāhu- "arm, forearm;" Gk. pechys "forearm, arm, ell;" O.H.G. buog "shoulder;" Ger. Bug "shoulder;" Du. boeg; O.E. bôg, bôh "shoulder, bough;" E. bough " a branch of a tree;" PIE *bhaghu- "arm").

upper atmosphere
  هواسپهر ِ زبرین، جو ِ ~   
havâsepehr-e zabarin, javv-e ~

Fr.: atmosphère supérieure   

The general term applied to the atmosphere above the → troposphere.

upper; → atmosphere.

upper culmination
  بالست ِ زبرین   
bâlest-e zabarin

Fr.: culmination supérieure   

Same as → superior culmination.

upper; → culmination.

upper level
  تراز ِ بالا، ~ زبرین   
tarâz-e bâlâ (#), ~ zabarin (#)

Fr.: niveau supérieur   

In atomic physics, an initial energy state in an emission transition.

upper; → level.

upper limit
  حدِ بالا، ~ زبرین   
hadd-e bâlâ (#), ~ zabarin (#)

Fr.: limite supérieure   

Of an integral operator, the point at which the integration ends.

upper; → limit.

upper main sequence
  رشته‌ی ِ فریست ِ زبرین   
rešte-ye farist-e zabarin

Fr.: séquence principale supérieure   

A → main sequence star with a mass above 1.5 Msun. Upper main sequence stars have high central temperatures so that they produce their energy through the → CNO cycle. The outward energy flux is very high and therefore this flux cannot be maintained by → radiative transfer. Thus, upper main sequence stars have → convective cores. Outside the core, there is a → radiative zone. The mass of the convective core gradually diminishes as the hydrogen is consumed. The surface hydrogen is fully ionized and the → opacity is due to → electron scattering The opacity due to electron scattering.

upper; → main; → sequence.

upper mantle
  گوشته‌ی ِ زبرین   
gušte-ye zabarin

Fr.: manteau supérieur   

The upper part of the Earth's → mantle which begins at the base of the → crust around 35 km and extends downward to about 410 km.

upper; → mantle.

upper mass cut-off
  بره‌ی ِ بالایی ِ جرم، ~ زبرین ِ ~   
bore-ye bâlâyi-ye jerm, ~ zabarin-e ~

Fr.: coupure aux masses élevées   

Same as → upper mass limit.

upper; → mass; → cut-off.

upper mass limit
  حد ِ بالایی ِ جرم، ~ زبرین ِ ~   
hadd-e bâlâyi-ye jerm, ~ zabarin-e ~

Fr.: limite supérieure de masses   

The highest mass range admitted in a star formation model. The high mass end of the → initial mass function. The upper mass limit is a critical parameter in understanding → stellar populations, → star formation, and → massive star feedback in galaxies.

upper; → mass; → limit.

upper transit
  گذر ِ زبرین   
gozar-e zabarin (#)

Fr.: passage supérieur   

The movement of a celestial body across a celestial meridian's upper branch. Same as → upper culmination.

upper; → transit.

upstream
  فرازاب   
farâzâb (#)

Fr.: en amont   

1) Toward or in the higher part of a stream; against the current. → downstream
2) Directed upstream; situated upstream.

up; → stream.

Farâz, → height; water, → water.

uranium
  اورانیوم   
urâniyom (#)

Fr.: uranium   

A → radioactive metallic → chemical element; symbol U. → Atomic number 92; → atomic weight 238.0289; → melting post 1,132 °C; → boiling point 3,818°C; → specific gravity 19.1 at 25 °C. Uranium has 14 known → isotopes of which 238U is the most abundant in nature. This isotope (→ half-life 4.5 billion years) is 138 times more abundant than 235U (half-life 710 million years). The metal was first isolated by the French chemist Eugène-Melchior Peligot in 1841. See also: → uranium oxide, → uranium conversion, → uranium dioxide, → uranium enrichment, → uranium hexafluoride, → uranium-233, → uranium-235, → uranium-238, → plutonium, → fissile isotope, → fertile isotope, → yellowcake.

From the name of the planet → Uranus. The German chemist Martin-Heinrich Klaproth discovered the element in 1789, following the German/English astronomer William Hershel's discovery of the planet in 1781.

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