Search results
Results From The WOW.Com Content Network
Lunar distance (LD or ), or Earth–Moon characteristic distance, is a unit of measure in astronomy. More technically, it is the semi-major axis of the geocentric lunar orbit . The lunar distance is on average approximately 385,000 km (239,000 mi), or 1.28 light-seconds ; this is roughly 30 times Earth's diameter or 9.5 times Earth's ...
The lunar distance is the angle between the Moon and a star (or the Sun). In the above illustration the star Regulus is used. The altitudes of the two bodies are used to make corrections and determine the time. In celestial navigation, lunar distance, also called a lunar, is the angular distance between the Moon and another celestial body.
On average, the distance to the Moon is about 385,000 km (239,000 mi) from Earth's centre, which corresponds to about 60 Earth radii or 1.282 light-seconds. With a mean orbital velocity around the barycentre between the Earth and the Moon, of 1.022 km/s (0.635 miles/s, 2,286 miles/h), [ 6 ] the Moon covers a distance approximately its diameter ...
The semi-major axis of the geocentric lunar orbit, called the lunar distance, is approximately 400,000 km (250,000 miles or 1.28 light-seconds), comparable to going around Earth 9.5 times. [177] The Moon makes a complete orbit around Earth with respect to the fixed stars, its sidereal period, about once every 27.3 days.
More than one asteroid per year may be listed if its geocentric distance [note 1] is within a tenth of the lunar distance, or 0.10 LD. For comparison, since a satellite in a geostationary orbit has an altitude of about 36,000 km (22,000 mi), then its geocentric distance is 0.11 LD (approximately three times the width of the Earth).
The astronomical unit (symbol: au[1][2][3][4] or AU) is a unit of length defined to be exactly equal to 149,597,870,700 m. [5] Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its modern redefinition in 2012. The astronomical unit is used primarily for ...
The first United States spacecraft to orbit the Moon was Lunar Orbiter 1 on August 14, 1966. [13] The first orbit was an elliptical orbit, with an apolune of 1,008 nautical miles (1,867 km; 1,160 mi) and a perilune of 102.1 nautical miles (189.1 km; 117.5 mi). [14]
Luna 1. Luna 1, also known as Mechta (Russian: Мечта [mʲɪt͡ɕˈta], lit.: Dream), E-1 No.4 and First Lunar Rover, [4] was the first spacecraft to reach the vicinity of Earth's Moon, the first spacecraft to leave Earth's orbit, and the first to be placed in heliocentric orbit. Intended as a Moon impactor, Luna 1 was launched as part of ...