žirandegi-ye zamin-meqnâtisi, ~ zamin-meqnâti
Fr.: activité géomagnétique
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.
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.
tufân-e zamin-meqnâtisi, ~ zamin-meqnâti
Fr.: orage géomagnétique
A branch of geophysics concerned with the study of the Earth's → geomagnetic field, including its origin, spatial extent, and variations in time.
Of or pertaining to geometry or to the principles of geometry.
Adj. of → geometry
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.
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.
Fr.: horizon géométrique
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.
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.
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.
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.
Fr.: suite géométrique
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.
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.
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,"
The branch of physics that deals with the Earth and its environment, including meteorology, oceanography, seismology, and geomagnetism.
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).
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.
Of or pertaining to the force produced by the rotation of the Earth.