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: 4 Search : drag
drag
  ۱) کره، ۲) وارانه؛ ۳) کریدن، کراندن   
1) kerré, 2) vârâné; 3) kerridan, kerrandan

Fr.: 1) traînée, entraînement; 2) traînée; 3) traîner   

1) General: The act of dragging or the state of being dragged.
2) Fluid mechanics: The → force that opposes the relative motion of an object through a → fluid. In → aeronautics, the component of aerodynamic force parallel to the relative wind tending to reduce the forward motion of the airplane. See also → lift; → thrust.
3) To pull or be pulled with force, especially along the ground or other surface.

From O.N. draga, O.E. dragan "to draw," from P.Gmc. *dragan "to draw, pull," from PIE base *dhragh- "to draw, drag on the ground" (cf. Skt. dhrajati "pulls, slides in," L. trahere "to pull," Rus. drogi "wagon."

Kerr, kerré, kerridan "drag," cf. Laki keronen, Hamadâni kerândan "to pull along, drag," Tâleši kernye, Tabari kərəš "to drag;" Lori, Hamadâni kerr "line, scratch;" related to Mid/Mod.Pers. kešidan, kašidan "to draw, protract, trail, drag, carry;" kâštan, keštan, kâridan "to cultivate, to plant, to make furrows;" Av. kar- "to strew seed, cultivate," kāraiieiti "cultivates," karš- "to draw (a furrow), till, plant;" cf. Skt. kar- "to scatter, strew, pour out," kars-, kársati "to pull, drag, plow;" Gk. pelo, pelomai "to move, to bustle;" PIE base kwels- "to plow."
Vârâné, from vâ-, opposition prefix, → de-, + râné, from rândan "to push, drive, cause to go" (causative of raftan "to go, walk, proceed," present tense stem row-, Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

ether drag
  کره‌ی ِ اتر   
kerre-ye eter

Fr.: entraînement de l'éther   

A hypothesis put forward to explain the null measurement of the → ether drift. According to this hypothesis, the Earth somehow drags the ether with it as our planet rotates on its axis and revolves around the Sun. However, the ether drag hypothesis contradicts results from several experiments, including the → aberration of starlight.

ether; → drag.

frame dragging
  کرّه‌ی ِ چارچوب، چارچوب-کرّه   
kerre-ye cârcub, cârcub-kerré

Fr.: entraînement des repères, effet Lense-Thirring   

The alteration in the → free fall motion of a test → mass in the presence of a massive → rotating object, as compared to the identical case of a non-rotating object. This dragging of → inertial frames is predicted by → general relativity. Also called → Lense-Thirring effect.

frame; → drag.

Poynting-Robertson drag
  کره‌ی ِ پوینتینگ-رابرتسون   
kerre-ye Poynting-Robertson

Fr.: traînée de Poynting-Robertson   

A loss of → orbital angular momentum by tiny ring particles associated with their absorption and re-emission of → solar radiation. Also known as the → Poynting-Robertson effect (Ellis et al., 2007, Planetary Ring Systems, Springer).

Poynting-Robertson; → drag.