Geosynchronous orbit

A geosynchronous orbit is a geocentric orbit that has the same orbital period as the sidereal rotation period of the Earth. It has a semi-major axis of 42,164 km http://www.google.com/search?q=%28%2886%2C164.09%2F2%2Fpi%29%5E2*398600%29%5E%281%2F3%29.

Related Topics:
Orbit - Orbital period - Sidereal - Earth - Semi-major axis

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Synchronous orbits exist around all moons, planets, stars and black holes —unless they rotate so slowly that the orbit would be outside their Hill sphere. Most inner moons of planets have synchronous rotation, so their synchronous orbits are, in practice, limited to their leading and trailing Lagrange points. Objects with chaotic rotations (such as Hyperion) are also problematic, as their synchronous orbits keep changing unpredictably.

Related Topics:
Synchronous orbit - Hill sphere - Synchronous rotation - Lagrange point - Chaotic - Hyperion

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If a geosynchronous orbit is circular and equatorial then it is also a geostationary orbit, and will maintain the same position relative to the Earth's surface. If one could see a satellite in geostationary orbit, it would appear to hover at the same point in the sky, i.e., not exhibit diurnal motion, while one would see the Sun, Moon, and stars traverse the heavens behind it.

Related Topics:
Geostationary orbit - Diurnal motion

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A circular geosynchronous orbit in the plane of the Earth's equator has a radius of approximately 42,164 km (from the centre of the Earth) or approximately 35,790 km (22,240 statute miles) above mean sea level.

Related Topics:
35,790 km - Statute mile - Mean sea level

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