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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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.

Minkowski metric; → space-time.

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-zamân

Fr.: courbure de l'espace-temps   

curvature of space-time.

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-zamân

Fr.: 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.