An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 53 Search : metric
 Robertson-Walker metric   متریک ِ روبرتسون-واکر   metrik-e Robertson-Walker (#)Fr.: métrique de Robertson-Walker   The mathematical description of the interval (→ space-time separation) between → events ("points" in space-time) in a → homogeneous and → isotropic → Universe. It results from an exact solution of → Einstein's field equations of → general relativity. Under the assumptions, the Robertson-Walker interval is expressed by: ds2 = c2dt2 - R2(t) [dr2/(1 - kr2) + r2dθ2 + r2sin2θ dθ2)]. Same as Friedmann-Lemaître-Robertson-Walker metric. Compare → Minkowski metric.Named after Howard Percy Robertson (1903-1961), American mathematician and physicist, and Arthur Geoffrey Walker (1909-2001), British mathematician and physicist, for their contributions to physics and physical cosmology; → metric. Schwarzschild metric   متریک ِ شو‌آرتسشیلد   metrik-e SchwarzschildFr.: métrique de Schwarzschild   In → general relativity, the → metric that describes the → space-time outside a static mass with spherically symmetric distribution. skew-symmetric tensor   تانسور ِ پاد-همامون   tânsor-e pâdhamâmunFr.: tenseur antisymétrique   A tensor that is the negative of its → transpose. For example, a second-order covariant tensor Ajk if its components satisfy the equality: Ajk = - Akj. Also called antisymmetric tensor.→ skew; → symmetric; → tensor.Tânsor, → tensor; pâd-, → anti-; hamâmun, → symmetric. Spectro-Polarimetric High-contrast Exoplanet (SPHERE)      Fr.: Spectro-Polarimetric High-contrast Exoplanet (SPHERE)   The → extreme adaptive optics system and → coronagraphic facility at the → European Southern Observatory (ESO) → Very Large Telescope (VLT) (UT3) available from May 2014. Its primary science goal is imaging, low-resolution spectroscopic, and polarimetric characterization of → exoplanetary system at → visible and → near-infrared wavelengths (0.5-2.32 μm). SPHERE is capable of obtaining → diffraction-limited images at 0''.02 to 0''.08 resolution depending on the wavelength. Its → spectral resolution is 30 to 350, depending on the mode.→ spectro-; → polarimetric; → high; → contrast; → exoplanet. spectrophotometric   بیناب-شیدسنجیک   binâb-šidsanjikFr.: spectrophotométrie   Of or relating to → spectrophotometry.→ spectrum; → photometry. spectropolarimetric   بیناب-قطبش‌سنجی، بیناب-قطبش‌سنجیک   binâb-qotbešsanji, binâb-qotbešsanjikFr.: spectropoolarimétrique   Of or relating to → spectropolarimetry.→ spectropolarimetry; → -ic. stoichiometric   استویخیوسنجیک   stoyxiyosanjikFr.: stoechiométrique   1) Of or pertaining to → stoichiometry. 2) Pertaining to or involving substances that are in the exact proportions required for a given reaction.→ stoichiometry; → -ic. symmetric relation   بازانش ِ همامون   bâzâneš-e hamâmunFr.: relation symétrique   A relation between two quantities such that the first is to the second as the second is to the first. In symbols: a R b = b R a. For example, multiplication is an operation with a symmetric relation between the factors: 5 x 3 = 3 x 5.→ symmetric; → relation. symmetric tensor   تانسور ِ همامون   tânsor-e hamâmunFr.: tenseur symétrique   A tensor that is → invariant under any → permutation of its indices (→ index). In other words, a tensor that equals its → transpose. For example, a second-order → covariant tensor Ajk if its components satisfy the equality: Ajk = Akj.→ symmetric; → tensor. symmetric, symmetrical   همامون   hamâmunFr.: symétrique   Characterized by or exhibiting → symmetry.Adj. of → symmetry. trigonometric   سه‌برسنجیک   sebarsanjikFr.: trigonométrique, circulaire   Relating to or used in → trigonometry. → trigonometric function.→ trigonometry; → -ic. trigonometric function   کریای ِ سه‌برسنجیک   karyâ-ye sebarsanjikFr.: fonction circulaire, ~ trigonomtérique   A function of an angle, one of six functions (sine, cosine, tangent, cotangent, secant, and cosecant) that represent ratios of sides of right triangles. Also called circular function. trigonometric parallax   دیدگشت ِ سه‌برسنجی، ~ سه‌برسنجیک   didgašt-e sebarsanji, ~ sebarsanjikFr.: parallaxe trigonométrique   The → parallax of a nearby star (less than 300 → light-years) against the background of more distant stars resulting from the motion of the Earth in its orbit around the Sun.

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