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: 707
relative azimuth
  سوگان ِ بازانی   
sugân-e bâzâni

Fr.: azimut relatif   

The difference in → azimuth between the → Moon and the → Sun.

relative; → azimuth.

relative dating
  سن‌یابی ِ بازانی   
senn-yâbi-ye bâzâni

Fr.: datation relative   

A method of dating that can only tell us whether an event or object is older or younger than another event or object. In geology, different layers of rock are compared to determine an ordered sequence of events in geologic history. In contrast to → absolute dating, relative dating cannot give the actual age of a rock. See also → stratigraphy.

relative; → dating.

relative density
  چگالی ِ بازانی   
cagâli-ye bâzâni

Fr.: densité relative   

The ratio of the density of a substance to the density of a given reference material. For a solid or liquid, it is the density (at 20°C) relative to the maximum density of water (at 4°C). For a gas is its density divided by the density of hydrogen (or sometimes dry air) at the same temperature and pressure. Also called → specific density.

relative; → density.

relative error
  ایرنگ ِ بازانی   
irang-e bâzâni

Fr.: erreur relative   

The → absolute error divided by the true value x, that is: Δx/x. The result may be expressed as a percentile and is useful when we want to determine the error relative to the value of the exact quantity.

relative; → error.

relative frequency
  بسامد ِ بازانی   
basâmad-e bâzâni

Fr.: fréquence relative   

Statistics: The number of the occurrences of an event divided by the number of observations.

relative; → frequency.

relative humidity
  نم ِ بازانی   
nam-e bâzâni

Fr.: humidité relative   

The amount of moisture in the air compared to what the air can "hold" at that temperature. It is given by the ratio of the partial pressure of water vapor in the mixture to the saturated vapor pressure of water at a specific temperature.

relative; → humidity.

relative invariant
  ناورتای ِ بازانی   
nâvartâ-ye bâzâni

Fr.: invariant relatif   

A → relative tensor of order zero.

relative; → invariant.

relative permeability
  تراوایی ِ بازانی   
tarâvâyi-ye bâzâni

Fr.: perméabilité relative   

magnetic permeability.

relative; → permeability.

relative refractive index
  دیشن ِ شکستی ِ بازانی   
dišan-e šekasti-ye bâzâni

Fr.: indice de réfraction relatif   

The ratio of the sine of the angle of incidence to the sine of the angle of refraction for a ray passing out of one of the media into the other.

relative; → refractive; → index.

relative sunspot number
  شمار ِ بازانی ِ هورلک   
šomâr-e bâzâni-ye hurlak

Fr.: nombre relatif de taches solaires   

Same as → Wolf number and → sunspot number.

relative; → sunspot; → number.

relative tensor
  تانسور ِ بازانی   
tânsor-e bâzâni

Fr.: tenseur relatif   

A generalized tensor concept that is characterized by a → Jacobian matrix of transformation raised to a power called → weight of a tensor density. In practice, only relative tensors of weight 1 or -1 are used. The product of a relative tensor of weight -1 by another tensor of weight 1 is an → absolute tensor. Same as → tensor density.

relative; → tensor.

relative vector
  بردار ِ بازانی   
bordâr-e bâzâni

Fr.: vecteur relatif   

A → relative tensor of → order  → one.

relative; → vector.

relative velocity
  تندای ِ بازانی   
tondâ-ye bâzâni

Fr.: vitesse relative   

For two objects A and B, the velocity which B, supposing itself at rest, assigns to A.

relative; → velocity.

relatively
  بازانی‌وار، بازانانه   
bâzânivâr, bâzânâné

Fr.: relativement   

In a relative manner; in relation to something else.

From → relative + -ly "-vâr, -âné."

relativism
  بازانی‌باوری   
bâzâni-bâvari

Fr.: relativisme   

The belief that truth is relative and may vary from individual to individual, from group to group, or from time to time, having no objective standard.

From → relative + -ism a suffix used in the formation of nouns denoting action or practice, state or condition, principles, doctrines, etc.

Bâzâni-bâvari, from bâzâni, → relative, + bâvari, from bâvar "belief" (Mid.Pers. wâbar "beleif;" Proto-Iranian *uar- "to choose; to convince; to believe;" cf. Av. var- "to choose; to convince" varəna-, varana- "conviction, faith;" O.Pers. v(a)r- "to choose; to convince;" Skt. vr- "to choose," vara- "choosing").

relativist
  بازانی‌باور   
bâzâni-bâvar

Fr.: relativiste   

An adherent or advocate of relativism.

From → relative + -ist a suffix of nouns.

Adj. from → relativism.

relativistic
  بازانیگی‌مند، بازانیگی‌ور   
bâzânigimand, bâzânivar

Fr.: relativiste   

1) Physics: Relating to the → relativity theory.
2) Philosophy: Involving or characterized by → relativism.
See also:
non-relativistic, → relativistic aberration, → relativistic Doppler effect, → relativistic mass, → relativistic particle, → relativistic precession, → relativistic quantum mechanics, → relativistic redshift, → relativistic speed, → relativistic spin precession, → relativistic velocity, → ultrarelativistic, → ultrarelativistic gas.

From → relativist + → -ic.

relativistic aberration
  بیراهش ِ بازانیگی‌مند   
birâheš-e bâzânigimand

Fr.: aberration relativiste   

The aberration of light for an object moving with → relativistic speed. In contrast to the classical case, the → Lorentz transformation between the → rest frame of the observer and that of the object must be used. Relativistic aberration is expressed by the equation: cos φ' = (cos φ - )/(1 - cos φ.v/c), where φ is the classical → aberration angle, v the speed of the Earth, and c the → speed of light. It can also be expressed as: tan φ' = -(c/v)(1 - v2/c)1/2.

relativistic; → aberration.

relativistic Doppler effect
  اُسکر ِ دوپلر ِ بازانیگی‌مند   
oskar-e Doppler-e bâzânigimand

Fr.: effet Doppler relativiste   

The Doppler effect when the relative motion of the source and the observer is comparable to the speed of light. In that case the classical Doppler formula should be corrected for effects of the special theory of relativity (Lorentz transformation).

relativistic; → Doppler effect.

relativistic mass
  جرم ِ بازانیگی‌مند   
jerm-e bâzânigimand

Fr.: masse relativiste   

In → special relativity, the mass that is assigned to a body in motion. Einstein demonstrated that the velocity of the observer has an effect on the way inertial mass is measured. The relativistic mass is expressed by mt = m0 / [1 - (v/c)2]1/2, where m0 is the → rest mass, v is the velocity, and c the → velocity of light. The experimental evidence for this phenomenon is observed in the mass of high-speed electrons accelerated by magnetic fields. This formula shows that it is impossible for a mass to be accelerated to the velocity of light in a vacuum.

relativistic; → mass.

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