An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 430
geomagnetic activity
  ژیرندگی ِ زمین‌مغناتیسی، ~ زمین‌مغناتی   
žirandegi-ye zamin-meqnâtisi, ~ zamin-meqnâti

Fr.: activité géomagnétique   

The natural variations in the → geomagnetic field due to interactions of the Earth's field and → magnetosphere with energetic particles from the Sun.

geomagnetic; → activity.

geomagnetic excursion
  زچار ِ زمین‌مغناتی   
zocâr-e zamin-meqnâti

Fr.: excursion géomagnétique   

A geophysical event, distinguished from the → magnetic reversal, in which the Earth's magnetic field departs for a relatively short time from its usual near axial configuration, without establishing a reversed direction. During the excursion the intensity and direction of the Earth's magnetic field undergo drastic changes. Palaeomagnetic measurements have revealed that since the last full reversal the Earth's magnetic field has, for brief intervals, deviated from the behavior expected during "normal" secular variation.

geomagnetic; → excursion.

geomagnetic field
  میدان ِ زمین‌مغناتیسی، ~ زمین‌مغناتی   
meydân-e zamin-meqnâtisi, ~ zamin-meqnâti

Fr.: champ géomagnétique   

The magnetic field that is generated within the Earth and extends out around the Earth. The intensity of the magnetic field at the Earth's surface is about 0.32 → gauss at the equator and 0.62 gauss at the north pole.

geomagnetic; → field.

geomagnetic storm
  توفان ِ زمین‌مغناتیسی، ~ زمین‌مغناتی   
tufân-e zamin-meqnâtisi, ~ zamin-meqnâti

Fr.: orage géomagnétique   

A violent disturbance of the Earth's magnetic field, distinct from regular diurnal variations, following a → solar flare or → coronal mass ejection.

geomagnetic; → storm.

geomagnetism
  زمین‌مغنات‌مندی   
zamin-meqnâtmandi

Fr.: géomagnetsme   

A branch of geophysics concerned with the study of the Earth's → geomagnetic field, including its origin, spatial extent, and variations in time.

geo-; → magnetism.

geometric
  هندسی   
hendesi (#)

Fr.: géométrique   

Of or pertaining to geometry or to the principles of geometry.

Adj. of → geometry

geometric albedo
  سپیدای ِ هندسی   
sepidâ-ye hendesi

Fr.: albedo géométrique   

A measure of the → reflectivity of a surface, especially of the solar system bodies (planets, satellites or asteroids). It is the ratio of a body's brightness at zero → phase angle to the brightness of a perfectly diffusing disk with the same position and apparent size as the body. Geometric albedo depends on the radiation wavelength. The bolometric geometric albedo refers to reflectivity in all wavelengths. Compare with the → Bond albedo.

geometric; → albedo.

geometric delay
  درنگ ِ هندسی   
derang-e hendesi

Fr.: retard géométrique   

One of the two factors contributing to → gravitational lensing time delay that arises from the fact that the bent trajectory is longer than the straight one. The other factor is due to the → Shapiro time delay.

geometric; → delay.

geometric horizon
  افق ِ هندسی   
ofoq-e hendesi

Fr.: horizon géométrique   

Where the apparent → sea horizon would be if there were no → atmospheric refraction.

geometric; → horizon.

geometric mean
  میانگین ِ هندسی   
miyângin-e hendesi (#)

Fr.: moyenne géométrique   

The middle term in a → geometric progression. Of two terms, the geometric mean is the square root of their product. For example, the geometric mean of 4 and 9 is ± 6. For a series of n terms, it is expressed as: (a1.a2. ... .an)1/n.

geometric; → mean.

geometric optics
  نوریک ِ هندسی   
nurik-e hendesi

Fr.: optique géométrique   

A branch of physics that deals with reflection and refraction of rays of light without reference to the wave or physical nature of light.

geometric; → optics.

geometric progression
  فرایازی ِ هندسی   
farâyâsi-e hendesi (#)

Fr.: progression géométrique   

A → sequence in which the ratio of a term to its predecessor is the same for all terms. In general, the nth term has the form ar(n-1), where n is a positive integer, and a and r are nonzero constants; r is called the ratio or common ratio. Also called → geometric sequence.

geometric; → progression.

geometric scattering
  پراکنش ِ هندسی   
parâkaneš-e hendesi

Fr.: diffusion géométrique   

A type of scattering in which the wavelength (of the light or the sound) is much smaller than the size of object causing the scattering.

geometric; → scattering.

geometric sequence
  پی‌آیه‌ی ِ هندسی   
peyâye-ye hendesi

Fr.: suite géométrique   

geometric progression.

geometric; → sequence.

geometrical libration
  رخگرد ِ هندسی   
roxgard-e hendesi (#)

Fr.: libration géométrique   

Libration resulting from changes in the location of the observer with respect to body. More specifically, a lunar libration motion that results from the Earth based observer seeing the Moon from different directions at different times. There are three types of geometrical libration: → libration in longitude, → libration in latitude, and → diurnal libration. See also → physical libration.

geometric; → libration.

geometry
  هندسه   
hendesé (#)

Fr.: géométrie   

The branch of mathematics that deals with the nature of space and the size, shape, and other properties of figures as well as the transformations that preserve these properties.

From O.Fr. géométrie, from L. geometria, from Gk. geometria "measurement of earth or land," from → geo- + -metria, from metrein "to measure," → -metry.

Hendesé, Mid.Pers. handâxtan "to measure," Manichean Mid.Pers. hnds- "to measure," Proto-Iranian ham-, → com-, + *das- "to heap, amass;" cf. Ossetic dasun/dast "to heap up;" Arm. loanword dasel "to arrange (a crowd, people)," das "order, arrangement,"

geophysics
  زمین‌فیزیک   
zaminfizik (#)

Fr.: géophysique   

The branch of physics that deals with the Earth and its environment, including meteorology, oceanography, seismology, and geomagnetism.

geo-; → physics.

geopolitics
  زمین‌کاراهیک   
zamin-kârâhik

Fr.: géopolitique   

The study or the application of the influence of political and economic geography on the politics, national power, foreign policy, etc., of a state (Dictionary.com).

geo-; → politics.

geostationary orbit
  مدار ِ زمین‌ایست‌وّر   
madâr-e zamin-istvar

Fr.: orbite géostationnaire   

A satellite orbit in the plane of the Earth's equator and 35,880 km above it, at which distance the satellite's period of rotation matches the Earth's and the satellite always remains fixed in the same spot over the Earth.

Geostationary, from → geo- + → stationary; → orbit.

geostrophic
  زمین‌چرخشی   
zamincarxeši

Fr.: géostrophique   

Of or pertaining to the force produced by the rotation of the Earth.

From Gk. → geo- + Gk. strophe "a turning," from strephein "to turn," from PIE *strebh- "to wind, turn" + → -ic.

From zamin-, → geo-, + carxeši, → rotational.

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