An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1965 Search : ion
gosil (#)

Fr.: émission   

In an atom, a characteristic amount of energy radiated (as line emission) when an electron moves from an outer orbit to an inner orbit around the nucleus, corresponding to the lost energy of the electron.

From L. emissionem "a sending out," from emiss-, stem of emittere "send forth," from → ex- "out" + mittere "to send."

Gosil, variant gosi "sending away, dismission;" Mid.Pers. wisé "to despatch" (Parthian Mid.Pers. wsys- "to despatch;" Buddhist Mid.Pers. wsydy "to despatch;" Sogdian 'ns'yd- "to exhort"), from Proto-Iranian *vi-sid- "to despatch, send off," from prefix vi- "apart, away, out," + *sid- "to call."

emission band
  باند ِ گسیلی   
bând-e gosili

Fr.: bande d'émission   

In a spectrum, a combination of several closely spaced, often unresolved, → emission lines occurring across a limited range of wavelengths.

emission; → band.

emission coefficient
  همگر ِ گسیل   
hamgar-e gosil

Fr.: coefficient d'émission   

Electromagnetic flux emitted by a source per unit volume per unit time.

emission; → coefficient.

emission feature
  آرنگ ِ گسیل   
ârang-e gosil

Fr.: motif d'émission   

Any emission mark in the spectrum of a celestial object resulting from line formation or of unknown origin.

emission; → feature.

emission line
  خط ِ گسیلی   
xatt-e gosili (#)

Fr.: raie d'émission   

A bright line in the electromagnetic spectrum of a radiating substance caused by emission at a particular wavelength.

emission; → line.

emission measure
  اندازه‌ی ِ گسیل   
andâze-ye gosil

Fr.: mesure d'émission   

The product of the square of the electron density times the linear size of the emitting region (in parsecs).

emission; → measure.

emission nebula
  میغ ِ گسیلی   
miq-e gosil-i

Fr.: nébuleuse en émission   

An ionized nebula whose spectrum consists of → emission lines. → planetary nebula; → H II region.

emission; → nebula.

emission spectrum
  بیناب ِ گسیلی   
binâb-e gosili (#)

Fr.: spectre d'émission   

A spectrum consisting of emission lines, produced when the light does not undergo absorption between the source and the spectrograph.

emission; → spectrum.

darnehâneš (#)

Fr.: cryptage   

A process that transforms data into another format in such a way that only specific individual(s) can reverse the transformation. Encryption is for maintaining data confidentiality. See also → decryption and → encoding.

encrypt; → -tion.

energy generation equation
  هموگش ِ آزانش ِ کاروژ   
hamugeš-e âzâneš-e kâruž

Fr.: équation de génération d'énergie   

Of a stellar → nuclear fusion, the equation describing the → energy generation rate as a function of → density and → temperature.

energy; → generation; → equation.

energy generation rate
  نرخ ِ آزانش ِ کاروژ   
nerx-e âzâneš-e kâruž

Fr.: taux de génération d'énergie   

Of a stellar → nuclear fusion, the energy produced per unit mass per unit time, usually denoted ε (erg g-1s-1). The general form of the energy generation equation is: ε = ε0ρλTν, where ε0, ρ, and λ are constants over some efficiently restricted range of → temperature T, → density ρ, and → chemical composition. The temperature exponent ν is about 4, 15, and 40 for → proton-proton chain, → CNO cycle, and → triple alpha process, respectively.

energy; → generation; → rate.

epicyclic oscillation
  نوش ِ اپی-چرخه‌ای   
naveš-e apicarxe-yi

Fr.: oscillation épicyclique   

In a → disk galaxy, the motion of a star about the orbital → guiding center when it is displaced radially. See also → epicyclic frequency, → epicyclic theory.

epicyclic; → oscillation.

epoch of reionization (EoR)
  زیمه‌ی ِ بازیونش   
zime-ye bâzyoneš

Fr.: époque de réionisation   

reionization epoch.

epoch; → reionization.

epoch of thermalization
  زیمه‌ی ِ یکگرمایی   
zime-ye yekgarmâyi

Fr.: époque de thermalisation   

The period during the → early Universe before the → recombination era when the photons were hot enough to ionize hydrogen. The density was so high that the interactions between → matter and → radiation were very numerous. Therefore, matter and photons were in constant contact and their → temperatures were the same. As a result, the radiation became → thermalized, i.e. the → electromagnetic spectrum of the radiation became that of a → blackbody, a process called → thermalization. Since the time of recombination the photons of → cosmic background radiation have been free to travel uninhibited by interactions with matter. Thus, their distribution of energy is a perfect → blackbody curve, as predicted by the → Big Bang theory and shown by several observations, such as → Cosmic Background Explorer (COBE), → Wilkinson Microwave Anisotropy Probe (WMAP), and → Planck Satellite.

epoch; → thermalization.

  هموگ سازی   

Fr.: égalisation; équalisation   

The act of making equal or uniform.
Electronics: The reduction of frequency or phase distortion by introducing networks which compensate for the particular type of distortion over the required frequency band.

Noun of equalize.


Fr.: équation   

A statement asserting the equality of two numbers or two expressions. It consists of two parts, called sides or members of the equation, separated by the Same as → equality sign.

From L. æquation- "an equalizing," noun of → equate.

Verbal noun of hamugidan, → equate.

equation of motion
  هموگش ِ جنبش   
hamugeš-e jonbeš

Fr.: équation de mouvement   

1) Any equation that describes the motion of objects, i.e., variation of velocity, distance covered, acceleration, etc., as a function of time; e.g., V = V0 + at, S = Vt + (1/2)at2.
2) For a fluid, a relation, in its most fundamental form, equating the rate of change of momentum of a selected portion of fluid and the sum of all forces acting on that portion of fluid.
3) In quantum mechanics, an equation that governs the time variation of the → state of the system. → Schrodinger equation. However, in the Heisenberg formulation of quantum mechanics the equation of motion does not involve the states, which in this case is time independent, but rather the → observables of the system.

equation; → motion.

equation of state
  هموگش ِ حالت   
hamugeš-e hâlat

Fr.: équation d'état   

In physics and thermodynamics, the equation that describes the relationship between pressure, density, and temperature, e.g. → ideal gas law, → van der Waals equation, → polytropic process, → virial equation of state.

equation; → state.

equation of state parameter
  پارامون ِ هموگش ِ حالت   
pârâmun-e hamugeš-e hâlat

Fr.: paramètre de l'équation d'état   

In cosmology, a → dimensionless parameter introduced by the → equation of state representing the ratio of the pressure to the energy density of a fluid, such as the → dark energy: w = p/ρ. The → deceleration or → acceleration of an → expanding Universe depends on this parameter (→ accelerating Universe). A number of numerical values of this parameter are as follows: for the → cosmological constant: w = -1, for → non-relativistic matter (present-day → baryons): w = 0, and for → relativistic matter (photons, neutrinos): w = +1/3. Together with Ω(dark energy) and Ω(matter), w provides a three-parameter description of the dark energy. The simplest parametrization of the dark energy is w = constant, although w might depend on → redshift.

equation; → state; → parameter.

equation of the equinoxes
  هموگش ِ هموگانها   
hamugeš-e hamugânhâ

Fr.: équation des équinoxes   

The difference between → apparent sidereal time and → mean sidereal time. It is due to the nutation of the Earth's polar axis of rotation about its precessional motion. It ranges from +0.8 to +1.2 seconds. Also known as → nutation in right ascension.

equation; → equinox.

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