An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 10 Search : drift
continental drift
  دلک ِ قاره‌ها   
delek-e qârehâ

Fr.: dérive de continents   

A hypothesis proposed by Alfred Wegener (1912) suggesting that the → continents are not stationary, but drift through time. Wegener's hypothesis has since been developed and included in a new theory called → plate tectonics.

continental; → drift.

  ۱) دلک؛ ۲) دلکیدن   
1) delek; 2) delekidan

Fr.: 1) dérive; 2) dériver   

1a) General: A driving movement or force; impulse; impetus; pressure.
1b) Physics: A slight change of a quantity with time, for example the sensitivity of an electronic detector continuously operated during a long period as an effect of continued use.
1c) A slow change in frequency of a radio transmitter.
1d) Aerospace: The gradual deviation of a rocket or guided missile from its intended trajectory.
2) (v.intr.) To be carried along by currents of water or air, or by the force of circumstances.

From M.E. drift, from O.E. drifan "to drive," or from O.N. or M.Du. drift, from P.Gmc. *driftiz, related to *dribanan "to drive."

Delek from Lori, Laki, Hamadâni, Malâyeri "push, shove, drive;" variants Gilaki duko, Tâleši dako, Baluchi dhakkk(a) "push, shove, blow," Choresmian dh- "to hit," Kurd. dân/di- "to beat, hit," Proto-Iranian *daH- "to beat, hit, strike" (Cheung 2007); PIE base *dhen- "to hit, push;" delekidan, verb from delek.

drift curve
  خم ِ دلک   
xam-e delek

Fr.: courbe de passage   

In radio astronomy, the output response as a function of position for a given filter as the source passes through the beam.

drift; → curve.

drift rate
  نرخ ِ دلک   
nerx-e delek

Fr.: taux de dérive   

The amount of drift, in any of its several senses, per unit time.

drift; → rate.

drift velocity
  تندای ِ دلک   
tond-ye delek

Fr.: vitesse de dérive   

The average velocity of a charged particle in a plasma in response to an applied electric field.

drift; → velocity.

ether drift
  دلک ِ اتر   
delek-e eter

Fr.: dérive de l'éther   

1) The hypothetical motion of the supposed → ether relative to the Earth. The → Michelson-Morley experiment found no ether drift. An analogy is given by a boat drifting in a fast-flowing river due to the river's current. With the same power, the speed would be slower when sailing across the stream. Moreover, in order to reach directly opposite the starting point, the boat would have to be headed somewhat upstream. See also the → ether drag.
2) The motion of the Earth relative to the → rest frame defined by the → cosmic microwave background radiation.

ether; → drift.

frequency drift
  دلک ِ بسامد   
delek-e basâmad

Fr.: dérive de fréquence   

An undesired progressive change in an oscillator's frequency with time.

frequency; → drift.

radiant drift
  دلک ِ تابسر   
delek-e tâbsar

Fr.: dérive de radiant   

The apparent slow motion of the → radiant of a → meteor shower from night to night against the background stars due to the Earth moving in its orbit around the Sun.

radiant; → drift.


Fr.: congère   

A mound or bank of snow deposited as sloping surfaces and peaks, often behind obstacles and irregularities, due to eddies in the wind field.

snow; → drift.

Barf-rând "snowdrift, drfited snow" from barf, → snow, + rând "driving, drfit; drifted," 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"); barf-e bâd âvard "snow brought by wind," from barf + bâdwind + âvard, short for âvardé "brought," p.p. of âvardan "to bring; to cause, produce" (Mid.Pers. âwurtan, âvaritan; Av. ābar- "to bring; to possess," from prefix ā- + Av./O.Pers. bar- "to bear, carry," bareθre "to bear (infinitive)," bareθri "a female that bears (children), a mother;" Mod.Pers. bordan "to carry;" Skt. bharati "he carries;" Gk. pherein; L. fero "to carry").

star drift
  دلک ِ ستارگان   
delek-e setâregân

Fr.: dérive stellaire   

The relative motion of two groups of stars in the Galaxy moving in opposite directions.

star; → drift.