Cartesian vortex theory
negare-ye gerdšâr-e Descartes
Fr.: 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.
Fr.: tourbillon convectif
A whirling mass of water or air.
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.