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: 3079 Search : on
aberrational day number
  شماره‌ی ِ روز ِ بیراهشی   
šomâre-ye ruz-e birâheši

Fr.: nombre de jours d'aberration   

A → Besselian day number denoted by C or D.

aberration; → -al; → day; → number.

aberrational ellipse
  بیضی ِ بیراهشی   
beyzi-ye birâheši

Fr.: ellipse d'aberration   

The → locus of points on the → celestial sphere occupied by a star during the annual → revolution of the → Earth about the → Sun due to → annual aberration. annual aberration.

aberrational; → ellipse.

ablation
  فرساب   
farsâb (#)

Fr.: ablation   

The → erosion of a surface through a process such as → vaporization or → friction.

L. ablatio, ablation, from ablatus, from ab- "away" + latus "carried."

Farsâb from far-, prefix denoting "abundance, excess" + sâb present stem of sâbidan "to rub, wear out," variants sâyidan, pasâvidan "to touch," Khotanese sauy- "to rub," Sogdian ps'w- "to touch," Proto-Iranian *sau- "to rub."

abortion
  فگانه، فگانش   
fagâné, fagâneš

Fr.: avortement   

The stopping of a process; a result of such termination.

Verbal noun of → abort.

absolute acceleration
  شتاب ِ اوست   
šetâb-e avast

Fr.: accélération absolue   

For a body that moves with respect to a rotating → reference frame, the vector sum of the observed acceleration, the → Coriolis acceleration, and the → centrifugal acceleration. See also the → Coriolis theorem.

absolute; → acceleration.

absorption
  درشم   
daršam

Fr.: absorption   

1) General: The process or fact of absorbing.
2) Physics: The action of energy or matter penetrating or being assimilated into a body of matter with no reflection or emission. → adsorption, → desorption, → sorption.
See also: → absorption band, → absorption coefficient, → absorption curve, → absorption feature, → absorption line, → absorption nebula, → absorption spectrum, → atmospheric absorption, → discrete absorption component, → foreground absorption, → intergalactic absorption, → internal absorption, → interstellar absorption, → mass absorption coefficient, → photoabsorption, → selective absorption, → self-absorption.

Verbal noun of → absorb; → -tion, from L. absorptionem.

absorption band
  باند ِ درشمی   
bând-e daršami

Fr.: bande d'absorption   

1) A series of very closely spaced absorption lines in stellar spectra resulting from the absorption of light by molecules. Bands caused by titanium oxide (→ TiO bands) and carbon compounds occur in the spectra of low temperature M and C stars.
2) A range of wavelengths, usually in electromagnetic radiation, that are absorbed by a given substance. Absorption bands are characteristic of molecules and correspond to changes of electron orbits in the molecules. See also → anomalous dispersion.

absorption; → band.

absorption coefficient
  همگر ِ درشم   
hamgar-e daršam

Fr.: coefficient d'absorption   

The fraction of normally incident light that is absorbed per unit path length or by a unit mass of absorbing medium.

absorption; → coefficient.

absorption curve
  خم ِ درشم   
xam-e daršam

Fr.: courbe d'absorption   

A graphic representation of the amount of radiant energy absorbed by a material as a function of the wavelength.

absorption; → curve.

absorption feature
  آرنگ ِ درشم   
ârang-e daršam

Fr.: motif d'absorption   

A dip in a spectrum indicating that light has been absorbed on the path from the emitting source to the observer. It may be a line, corresponding to a well-defined atomic or molecular transition, or a more complex feature whose physical origin is not necessarily understood.

absorption; → feature.

absorption line
  خط ِ درشمی   
xatt-e daršami

Fr.: raie d'absorption   

A dark line in the spectrum of a source produced by a lower temperature gas cloud lying between the source and the observer.

absorption; → line.

absorption nebula
  میغ ِ درشمی   
miq-e daršami

Fr.: nébuleuse par absorption, nébuleuse obscure   

A dark cloud of dust and gas that absorbs light from and impedes the view of background stars; dark nebula.

absorption; → nebula.

absorption spectrum
  بیناب ِ درشمی   
binâb-e daršami

Fr.: spectre d'absorption   

A spectrum of absorption lines or bands, produced when light from a hot source, itself producing a continuous spectrum, passes through a cooler gas.

absorption; → spectrum.

abstraction
  آهنجش   
âhanješ (#)

Fr.: abstraction   

1) The mental process in which an element or quality is separated from a total object. Also the result of this process.
2) Chemistry: → abstraction reaction.

Verbal noun from → abstract; → -tion.

abstraction reaction
  واژیرش ِ آهنجش   
vâžireš-e âhanješ (#)

Fr.: réaction d'abstraction   

Chemistry: A bimolecular chemical reaction that involves removal of an atom or ion from a molecule. For example, hydrogen abstraction from methane: CH4 + Cl → CH3 + HCl.

abstraction; → reaction.

accelerated motion
  جنبش ِ شتابدار   
jonbeš-e šetâbdâr (#)

Fr.: mouvement accéléré   

The motion of an object subject to → acceleration. Opposite to → uniform motion.

Accelerated, from → accelerate; → motion.

Jonbeš, → motion; šetâbdâr "accelerated," from šetâbaccelerate + dâr "having, possessor" (from dâštan "to have, to possess," Mid.Pers. dâštan, O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind;" cf. Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE *dher- "to hold, support").

accelerating expansion of the Universe
  سپانش ِ شتابنده‌ی ِ گیتی   
sopâneš-e šetâbande-ye giti

Fr.: expansion accélérée de l'Univers   

accelerating Universe.

accelerating; → expansion; → Universe.

acceleration
  شتاب   
šetâb (#)

Fr.: accélération   

The rate at which the velocity of an object changes with time.

Acceleration, from accelerate, from L. accelerare "quicken," from → ad- "to" + celerare "hasten," from celer "swift" (cf. Skt. car, carati "to move, go, drive," Gk. keles "fast horse, horse race," Av. kar- "to walk, move, go around," Mod.Pers. cal, calidan "to move, to go, to walk" (jald? "quick, active, brisk"), Gilaki/Hamadâni jal "quick, fast,"Lori žil "motion, impulse"); PIE *kel- "to drive, set in swift motion."

Šetâb "quickness, haste, speed," Mid.Pers. ôštâp "hurry, haste," ôštâftan "to hurry, hasten," from *abi.stap-, from abi- " to; in addition to; against" + *stap- "to oppress," Arm. (loanword) štap "haste, trouble."

acceleration of gravity
  شتاب ِ گرانی   
šetâb-e gerâni

Fr.: accélération de la gravité   

The acceleration that an object experiences because of gravity when it falls freely close to the surface of a massive body, such as a planet. Same as → gravitational acceleration.

acceleration; → gravity.

acceleration parameter
  پارامون ِ شتاب   
pârâmun-e šetâb

Fr.: paramètre d'accéleration   

A measure of the departure from a constant rate of the acceleration of the Universe, expressed by: q(t) = R(t)R ..(t)/R .2(t), where R(t) represents the size of the Universe at time t. Traditionally, a negative sign is inserted in the above equation for the → deceleration parameter.

acceleration; → parameter.

<< < "no abe acc act aff ama ani ant aps ast atm aut bar bif Boh bou cal car Cen chi Cla col com com Com con con con con con con con con con con con con cor cor Cou cur dec def Den det dif dim dis dis dou E-t edi ele ell ene ero exa exp ext fer Fla fra FU Gam geo gra gra had har hig Hub Hyp imp ind inf ins int int ion iro ite Kep lar lep lin lon lun mag mas mer mig mol Moo mut neg new New non non non nuc obs on- opt Ori oxi par per per phl pho Pla ple pol pos pre Pro pro pub qua rad rad rec red reg rem res rev rot Sak Sco sec seg sha sim sol sou sph sta ste Str sub sup T a the Tho tra tre tum uni vel vis wav wor > >>