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: 10 Search : quality
Aristarchus' inequality
  ناهموگی ِ اریستارخوس   
nâhamugi-ye Aristarchus

Fr.: inégalité d'Aristarque   

Put in modern notation, if α and β are acute angles and if β <α, then sin α / sin β <α / β < tan α / tan β. Aristarchus probably used this inequality to show that the Sun is between 18 and 20 times as far from the Earth as the Moon is.

Aristarchus of Samos (c.310-c.230 BC); → inequality.

Bell's inequality
  ناهموگی ِ بل   
nâhamugi-ye Bell

Fr.: inégalité de Bell   

Any of a large number of inequality relations developed to study the → hidden variable hypothesis suggested in the → EPR paradox. Using Bell's inequalities, the → Aspect experiment showed that no local hidden variable theory can make predictions in agreement with those of quantum mechanics. If, in a measurement, the inequality is violated, the measurement is in agreement with the predictions of the quantum theory. If the equality is satisfied, it suggests that a classical, causal, and local model is adequate to explain the outcome of the measurements. See also → quantum entanglement.

John Stewart Bell (1928-1990); → inequality.

equality
  هموگی، برابری   
hamugi

Fr.: égalité   

1) The state or quality of being equal.
2) Math.: A → statement of two → mathematical objects being equal. Like → equations, equalities are written as two mathematical objects connected by the → equality sign.

M.E. from L. aequalitat-, stem of aequalitats, → equal + -ity.

Hamugi noun of hamug, → equal.

equality sign
  نشانه‌ی ِ هموگی   
nešâne-ye hamugi

Fr.: signe d'égalité   

Same as → equals sign.

equality; → sign.

image quality
  چونی ِ تصویر   
cuni-ye tasvir

Fr.: qualité d'image   

1) The degree of visibility of relevant → information in an image.
2) The → full-width at half-maximum of a long exposure stellar image obtained by an instrument mounted on a telescope observing in the presence of → seeing.

image; → quality.

inequality
  ناهموگی، نابرابری   
nâhamugi, nâbarâbari

Fr.: inégalité   

1) A statement of the form a ≠ b, a > b, or a < b, asserting one quantity is greater than or less than another quantity. → equality.
2) An irregularity in the movement of a celestial object in its orbit about another which cannot be explained by their mutual gravitational attraction. Irregularities are often due to perturbation by other neighboring objects.

in-; → equality.

parallactic inequality
  ناهموگی ِ دیدگشتی   
nâhamugi-ye didgašti

Fr.: inégalité parallactique   

An irregularity in the Moon's motion caused by the Sun's gravitational attraction, which sets the Moon ahead or behind its normal orbital position. The Moon is about 2 arcminutes ahead of its expected position at first quarter, and a similar amount behind at last quarter.

parallactic; → inequality.

quality
  چونی   
cuni (#)

Fr.: qualité   

1) The general standard or grade of something.
2) → image quality.
3) → sound quality.

M.E. qualite, from O.Fr. qualite (Fr. qualité), from L. qualitas, from qual(is) "of what sort?" + → -ity.

Cuni, from Mid.Pers. cigôn "how?," cigônêh "nature, character," O.Pers/Av. ci- "what, any," collateral stem to ka- "who?, what?" (cf. Skt. ka-; Gk. po-; L. quo-; E. what, who; PIE *qwos/*qwes) + Av. gaona- "color" (Mid.Pers. gônak "kind, species").

sound quality
  چونی ِ صدا   
cuni-ye sedâ

Fr.: qualité de son   

The number of → overtones present in a sound and their respective intensity. Like → loudness, it is a subjective quantity and cannot be measured with instruments.

sound; → quality.

triangle inequality
  ناهموگی ِ سه‌بری   
nâhamugi-ye sebari

Fr.: inégalité triangulaire   

1) A theorem according to which any side of a triangle is always shorter than the sum of the other two sides.
2) The third requirement for a → distance function describing a → metric space.

triangle; → inequality.