# 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: 3 Search : vortex
 Cartesian vortex theory   نگره‌ی ِ گردشار ِ دکارت   negare-ye gerdšâr-e DescartesFr.: théorie des vortex de Descartes   A mechanical model put forward before Newton's theory of gravity to explain the revolution of the planets around the Sun. Descartes in his 1644 Principia Philosophiae postulated that the space between the Sun and the planets is filled with matter in the form of a fluid. The fluid rotates in countless whirlpools, one for each planet, thus carrying the planets along in their flow. The vortices vary in size and are contiguous as well as nested. Descartes believed that two objects can exert force on each other only when they are in physical contact. This is why he postulated that space is filled with matter. Newton refuted the vortex theory, using the principle of → action at a distance on which relies his → law of universal gravitation.→ Cartesian; → vortex; → theory. convective vortex   گردشار ِ همبزی   gerdšâr-e hambaziFr.: tourbillon convectif   A common feature of the atmosphere that ranges from small-scale → vortices such as → dust devils, to large-scale systems such as → cyclones.→ convective; → vortex. vortex   گردشار   gerdšâr (#)Fr.: vortex   Meteo.: A whirling mass of water or air. A pattern of rotation in which the rotation direction rotates by 360° along any path which surrounds the centre of the vortex.From L. vortex, variant of vertex "whirlpool; whirlwind, an eddy of water, wind, or flame;" from stem of vertere "to turn," cognate with Pers. gardidan, as below.Gerdšâr (on the model of gerdâb "whirlpool" and gerdbâd "whirlwind"), from gard present stem of gardidan "to turn, to change" (Mid.Pers. vartitan "to change, to turn;" Av. varət- "to turn, revolve;" cf. Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend") + šâr, from šâré, → fluid.