semidiurnal arc
1semidiurnal arc — noun : the arc described by a heavenly body (as the sun) between its meridian and its rising or setting …
2Semidiurnal — Sem i*di*ur nal, a. 1. Pertaining to, or accomplished in, half a day, or twelve hours; occurring twice every day. [1913 Webster] 2. Pertaining to, or traversed in, six hours, or in half the time between the rising and setting of a heavenly body;… …
3Indian Ocean — an ocean S of Asia, E of Africa, and W of Australia. 28,357,000 sq. mi. (73,444,630 sq. km). * * * Indian Ocean Introduction Indian Ocean Background: The Indian Ocean is the third largest of the world s five oceans (after the Pacific Ocean and… …
4Atlantic Ocean — an ocean bounded by North America and South America in the Western Hemisphere and by Europe and Africa in the Eastern Hemisphere. ab. 31,530,000 sq. mi. (81,663,000 sq. km); with connecting seas ab. 41,000,000 sq. mi. (106,100,000 sq. km);… …
5geomagnetic field — Magnetic field associated with the Earth. It is essentially dipolar (i.e., it has two poles, the northern and southern magnetic poles) on the Earth s surface. Away from the surface, the field becomes distorted. Most geomagnetists explain the… …
6geoid — geoidal, adj. /jee oyd/, n. 1. an imaginary surface that coincides with mean sea level in the ocean and its extension through the continents. 2. the geometric figure formed by this surface, an ellipsoid flattened at the poles. [1880 85; < Gk… …
7Climate of Mars — Mosaic image of Mars as seen by Viking 1, 22 February 1980 The climate of Mars has been an issue of scientific curiosity for centuries, not least because Mars is the only terrestrial planet whose surface can be directly observed in detail from… …
8Pacific Ocean — an ocean bordered by the American continents, Asia, and Australia: largest ocean in the world; divided by the equator into the North Pacific and the South Pacific. 70,000,000 sq. mi. (181,300,000 sq. km); greatest known depth, 35,433 ft. (10,800… …
9gravitation — gravitational, adj. gravitationally, adv. /grav i tay sheuhn/, n. 1. Physics. a. the force of attraction between any two masses. Cf. law of gravitation. b. an act or process caused by this force. 2. a sinking or falling …
10Sea level — For the sea level change associated with the current episode of global warming, see current sea level rise. For other uses, see Sea level (disambiguation). This marker indicating the sea level is placed on the path from Jerusalem to the Dead Sea …
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