An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 742
radiant drift
  دلک ِ تابسر   
delek-e tâbsar

Fr.: dérive de radiant   

The apparent slow motion of the → radiant of a → meteor shower from night to night against the background stars due to the Earth moving in its orbit around the Sun.

radiant; → drift.

radiant energy
  کاروژ ِ تابشی   
kâruž-e tâbeši

Fr.: énergie radiative   

The energy that is transmitted in the form of → radiation, in particular as → electromagnetic radiation.

radiant; → energy.

radiant flux
  شار ِ تابشی   
šâr-e tâbeši (#)

Fr.: flux radiatif   

Rate of flow of energy as → radiation.

radiant; → flux.

radiant intensity
  درتنویی ِ تابشی   
dartanuyi-ye tâbeši

Fr.: intensité de rayonnement   

A measure of the amount of radiation emitted from a point expressed as the radiant flux per unit solid angle leaving this source.

radiant; → intensity.

tâbidan (#)

Fr.: rayonner   

To send out → energy, such as → heat or → light, in the form of → rays or → waves.

From L. radiat(us), p.p. of radiare "to shine, to beam" + -ate verbal suffix.

Tâbidan, variants tâftan "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."

tâbeš (#)

Fr.: radiation, rayonnement   

The emission of any → rays, → waves, or → particles from a source; usually applied to the → emission of → electromagnetic energy.

Verbal noun of → radiate.

radiation belt
  کمربند ِ تابش، ~ تابشی   
kamarband-e tâbeš (#), ~ tâbeši (#)

Fr.: ceinture de radiations   

A ring-shaped region in the → magnetosphere of a planet in which charged particles are trapped by the planet's magnetic field. The radiation belts surrounding Earth are known as the → Van Allen belts.

radiation; → belt.

radiation constant
  پایای ِ تابش   
pâypa-ye tâbeš

Fr.: constante de rayonnement   

Same as → radiation density constant.

radiation; → constant.

radiation damping
  میرایی ِ تابشی   
mirâyi-e tâbeši

Fr.: amortissement par rayonnement   

Damping of a system which loses energy by → electromagnetic radiation.

radiation; → damping.

radiation density constant
  پایای ِ چگالی ِ تابش   
pâypa-ye cagâli-ye tâbeš

Fr.: constante de rayonnement   

The constant related to the total energy radiated by a → blackbody and defined as: a = 4σ/c, where σ is the → Stefan-Boltzmann constant and c the → speed of light. Its value is a = 7.5657 x 10-15 erg cm-3 K-4. Same as → radiation constant.

radiation; → density; → constant.

radiation era
  دوران ِ تابش   
dowrân-e tâbeš

Fr.: ère du rayonnement   

The epoch in the history of the Universe, lasting from the → Big Bang until about 400,000 years later, when the temperature had dropped to 109 K and the rate of electron-positron → pair annihilation exceeded the rate of their production, leaving radiation the dominant constituent of the Universe. The radiation era was followed by the → matter era.

radiation; → era.

radiation field
  میدان ِ تابش   
meydân-e tâbeš

Fr.: champ de rayonnement   

1) The portion of an → electromagnetic field outside the → induction field where there is a power flow of both → magnetic and → electric components in a well-defined relationship.
2) → interstellar radiation field

radiation; → field.

radiation length
  درازای ِ تابش   
derâzâ-ye tâbeš

Fr.: longueur de rayonnement   

The mean distance traveled by a photon or particle in a given medium before its energy is reduced by a factor e due to its interaction with matter.

radiation; → length.

radiation pattern
  الگو‌ی ِ تابش   
olgu-ye tâbeš

Fr.: diagramme de rayonnement   

Same as → antenna pattern.

radiation; → pattern.

radiation pressure
  فشار ِ تابش   
fešâr-e tâbeš

Fr.: pression de radiation   

The → momentum carried by → photons to a surface exposed to → electromagnetic radiation. Stellar radiation pressure on big and massive objects is insignificant, but it has considerable effects on → gas and → dust particles. Radiation pressure is particularly important for → massive stars. See, for example, → Eddington limit, → radiation-driven wind , and → radiation-driven implosion. The → solar radiation pressure is also at the origin of various physical phenomena, e.g. → gas tails in → comets and → Poynting-Robertson effect.

radiation; → pressure.

radiation sickness
  بیماری ِ تابشی   
bimâri-ye tâbeši

Fr.: mal des rayons   

An illness resulting from excessive exposure to ionizing radiation. The earliest symptoms are nausea, vomiting, and diarrhea, which may be followed by loss of hair, hemorrhage, inflammation of the mouth and throat, and general loss of energy.

radiation; sickness, M.E. siknesse, seknesse; O.E. sēocnesse, from seoc + suffix -ness.

Bimâri "sickness, infirmity, disease," from bimâr "sick, infirm, afflicted;" Mid.Pers. vêmâr "sick, ill;" maybe by corruption of Proto-Iranian *amavayā-bara- "bearing illness;" cf. Av. amavayā- "pain, suffering, affliction;" Skt. ámīvā- "pain, grief, distress" + *bara- "bearing;" cf. Av. bar- "to bear, carry;" Mod.Pers. bar-, bordan "to bear, carry, lead." Alternatively, from *vi-mar-, prefixed *mar- "to die;" cf. Av. mar- "to die;" Mod.Pers. mir-, mordan "to die;" Skt. mar- "to die;" cognate with Gk. emorten "died;" L. morior "to die;" tâbeši related to tâbeš, → radiation.

radiation spectrum
  بیناب ِ تابش   
binâb-e tâbeš

Fr.: spectre de rayonnement   

The components of radiation arranged in order of their wavelengths, frequencies, or quantum energies. For particle radiation they are arranged in order of their kinetic energies.

radiation; → spectrum.

radiation temperature
  دمای ِ تابش   
damâ-ye tâbeš

Fr.: température de rayonnement   

The temperature of a source calculated assuming that it behaves as a → blackbody that radiates with the same intensity at the same frequency. Compared to the → effective temperature, the radiation temperature is measured over a narrow region of the → electromagnetic spectrum.

radiation; → temperature.

radiation transfer
  تراواژ ِ تابش   
tarâvâž-e tâbeš

Fr.: transfert radiatif, ~ de rayonnement   

radiative transfer.

radiation; → transfer.

radiation transfer equation
  هموگش ِ تراواژ ِ تابش   
hamugeš-e tarâvâž-e tâbeš

Fr.: équation de transfert radiatif, ~ de rayonnement   

radiative transfer equation.

radiation; → transfer; → equation.

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