# 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: 6 Search : space-time
 curvature of space-time   خمیدگی ِ فضا-زمان   xamidegi-ye fazâ-zamân (#)Fr.: courbure de l'espace-temps   According to → general relativity, → space-time is curved by the presence of → matter. The curvature is described in terms of → Riemann's geometry. In → cosmological models three types of curvature are considered: positive (spherical, → closed Universe), zero (Euclidean, → flat Universe), and negative (hyperbolic, → open Universe). See also → curvature constant.→ curvature; → space-time. Minkowski space-time   فضا-زمان ِ مینکوفسکی   fazâ-zamân-e Minkowski (#)Fr.: espace-temps de Minkowski   A completely flat four-dimensional space, which contains no gravitating matter, used in the theory of special relativity. space-time   فضا-زمان   fazâ-zamân (#)Fr.: espace-temps   A physical entity resulting from the union of space and time concepts. In its most simple version space-time is the four-dimensional continuum, having three spatial coordinates and one temporal coordinate, in which any → event or physical object is located. In → special relativity it is Minkowski's flat space-time. In → general relativity, it is described by a curved entity characterized by a → metric. Free-fall motion describes the → geodesic of this curved space-time. It may have additional dimensions in the context of speculative theories, such as → string theory.→ space; → time. space-time curvature   خمیدگی ِ فضا-زمان   xamidegi-ye fazâ-zamânFr.: courbure de l'espace-temps   → space; → time; → curvature. space-time diagram   نمودار ِ فضا-زمان   nemudâr-e fazâ-zamân (#)Fr.: diagramme espace-temps   A simple way of representing the → space-time continuum, usually including time and only one spatial dimension. The curve of a particle's equation of motion on a space-time diagram is called a → world line. Same as → Minkowski diagram.→ space; → time; → diagram. space-time interval   اندروار ِ فضا-زمان   andarvâr-e fazâ-zamânFr.: intervalle espace-temps   1) In Einstein's → theory of relativity, ds2 = c2dt2 - dx2 - dy2 - dz2. 2) In → Newtonian mechanics, time interval: dt; space interval at fixed time: dl2 = dx2 + dy2 + dz2.→ space-time; → interval.