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: 10 Search : geometric
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.