An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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<< < abs ann con deg exc gen hie int mic ove reg tem > >>

Number of Results: 232 Search : era
conglomerate
  هاگلمیدن   
hâgolemidan

Fr.: conglomérer   

1) Anything composed of heterogeneous materials or elements.
2) Geology: A sedimentary rock made of rounded rock fragments (greater than two millimeters in diameter), such as pebbles, cobbles, and boulders, in a finer-grained matrix.

From L. conglomeratus, p.p. of conglomerare "to roll together," from → com- "together" + glomerare "to gather into a ball," from glomus (genitive glomeris) "a ball," globus "globe;" PIE *gel- "to make into a ball."

Hâgolemidan, from hâ- "together," → com-, + golem "glomus," → agglomerate.

conglomeration
  هاگلمش   
hâgolemeš

Fr.: conglomération   

1) The act of conglomerating; the state of being conglomerated.
2) a cohering mass; cluster (Dictionary.com).

Verbal noun of → conglomerate.

considerable
  آگاریدنی   
âgâridani

Fr.: considérable   

1) Rather large or great in size, distance, extent, etc.
2) Worthy of respect, attention, etc.; important; distinguished (dictionary.com).

consider; → -able.

consideration
  آگارش   
âgâreš

Fr.: considération   

The act or an instance of considering.

consider; → -tion.

Coriolis acceleration
  شتاب ِ کوریولیس   
šetâb-e Coriolis (#)

Fr.: accélération de Coriolis   

The apparent acceleration corresponding to the → Coriolis force. It is the acceleration which, when added to the acceleration of an object relative to a rotating → reference frame and to its → centrifugal acceleration, gives the acceleration of the object relative to a fixed reference frame. Coriolis acceleration equals 2ω x v, where ω is the → angular velocity of the rotating reference frame and v is the radial velocity of a particle relative to the center of the rotating reference frame.

Coriolis effect; → force.

corotating interaction region (CIR)
  ناحیه‌ی ِ اندرژیرش ِ هم‌چرخنده   
nâhiye-ye andaržireš-e hamcarxandé

Fr.: région d'interaction en corotation   

A spiral-shaped density enhancement formed around a star when fast stellar winds collide with slower material. This large-scale wind structure can extend from the stellar surface to possibly several tens of stellar radii. The CIRs can be produced by intensity irregularities at the stellar surface, such as dark and bright spots, magnetic loops and fields, or non-radial pulsations. The surface intensity variations alter the radiative wind acceleration locally, which creates streams of faster and slower wind material. CIRs are responsible for the → discrete absorption components seen in some ultraviolet → resonance lines of → hot stars (S. R. Cranmer & S. P. Owocki, 1996, ApJ 462, 469).

corotate; → interaction; → region.

cosmic acceleration
  شتاب ِ کیهانی   
šetâb-e keyhâni

Fr.: accélération cosmique   

accelerating Universe.

cosmic; → acceleration.

Coulomb interaction
  اندرژیرش ِ کولن   
andaržireš-e Coulomb

Fr.: interaction de Coulomb   

The reciprocal force between two or more → charged particles according to → Coulomb's law.

coulomb; → interaction.

coverage
  پوشش   
pušeš (#)

Fr.: couverture   

1) General: The extent to which something is covered.
2) Astro.: The total area of the sky observed in a particular → sky survey. See also → fractional sky coverage.
3) The area within which a radio signal sent by a transmitter is received reliably .
4) In film making, the shooting of a scene from various views and using various exposures.

From → cover + -age a suffix forming abstract nouns.

cover.

creation operator
  آپارگر ِ آفرینش   
âpârgar-e âfarineš

Fr.: opérateur de création   

An operator that acts on the → eigenstate describing the → harmonic oscillator to raise its → energy level by one step. The creation operator is the → Hermitian conjugate operator of the → annihilation operator.

creation; → operator.

Curie temperature
  دمای ِ کوری   
damâ-ye Curie (#)

Fr.: température de Curie   

The highest temperature for a given → ferromagnetic substance above which the → magnetization is lost and the substance becomes merely → paramagnetic. The Curie temperature of iron is about 1043 K and that of nickel 631 K.

Named after the French physicist Pierre Curie (1859-1906), a pioneer in magnetism, crystallography, and radioactivity. In 1903 he received the Nobel Prize in Physics with his wife Marie Curie (1867-1934, née Maria Skłodowska), and Henri Becquerel (1852-1908); → temperature.

cyclic quadrilateral
  چهاربر ِ چرخه‌ای   
cahârbar-e carxe-yi

Fr.: quadrilatère cyclique   

A quadrilateral in which all four vertices lie on the circumference of a circle.

cyclic; → quadrilateral.

d'Alembertian operator
  آپارگر ِ دالامبر   
âpârgar-e d'Alembert

Fr.: d'alembertien   

A second order, → partial differential operator in space-time, defined as: ▫2 = ∂2/∂x2 + ∂2/∂y2 + ∂2/∂z2 - (1/c2)∂2/∂t2, or ▫2 = ∇2 - (1/c2)(∂2/∂t2), where ∇2 is the → Laplacian and c is the → speed of light. This operator is the square of the → four-dimensional operator  ▫, which is Lorentz invariant.

d'Alembert's principle; → operator.

Debye temperature
  دمای ِ دبی   
damâ-ye Debye (#)

Fr.: température de Debye   

The characteristic → temperature of the → crystal as given by the → Debye model of → specific heats.

debye; → temperature.

decelerate
  واشتابیدن؛ واشتاباندن   
vâšetâbidan (#); vâšetâbândan (#)

Fr.: décélérer   

(v.intr.) To slow down. (v.tr.) To decrease the velocity of.

From → de- + (ac)celerate, from → accelerate.

Vâšetâbidan, from vâ-de- + šetâbidan, → accelerate.

deceleration
  واشتاب   
vâšetâb (#)

Fr.: décéleration   

The act or process of moving, or of causing to move, with decreasing speed. Sometimes called negative acceleration.

Verbal noun of decelerate.

deceleration parameter
  پارامون ِ واشتاب   
pârâmun-e vâšetâb

Fr.: paramètre de décéleration   

A parameter designating the rate at which the expansion of the Universe would slow down owing to the braking gravitational effect of the matter content of the Universe. It is expressed by: q(t) = -R(t)R ..(t)/R .2(t), where R(t) represents the size of the Universe at time t. See also → expansion parameter; compare with → acceleration parameter.

deceleration; → parameter.

decoupling era
  دوران ِ واجفسری، ~ واجفتش   
dowrân-e vâjafsari, ~ vâjofteš

Fr.: époque du découplage   

The era some 400,000 years after the → Big Bang, when the cosmic → blackbody radiation was last scattered by the matter. → decoupling. Same as → recombination era and → last scattering epoch.

decoupling; → era.

degeneracy
  واگنی   
vâgeni (#)

Fr.: dégénérescence   

1) General: Degenerate state or character. Reverting to an earlier, simpler, state.
2) Math.: Limiting case in which a class of object changes its nature so as to belong to another, usually simpler, class.
3) Physics: In quatum mechanics, the condition in which two or more different → wave functions of a system correspond to the same energy. In the case of atomic energy levels, the degeneracy can be removed, for example, by applying an electric field to the atom.
State or charcater of → degenerate matter.

From degener(ate), → degenerate, + -acy suffix of nouns of quality and state.

Vâgeni, from vâgen, → degenerate, + noun suffix -i.

degeneracy pressure
  فشار ِ واگنی   
fešâr-e vâgeni (#)

Fr.: pression de dégénérescence   

Pressure in a degenerate electron or neutron gas. → degenerate matter.

degeneracy; → pressure.

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