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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 circumference. Around 389 lunar distances make up an AU astronomical unit (roughly the distance from Earth to the Sun). Lunar distance is commonly used to express the distance to near ...
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 Moon is Earth's only natural satellite.It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Tidal forces between Earth and the Moon have synchronized the Moon's orbital period (lunar month) with its rotation period at 29.5 Earth days, causing the same side of the Moon to always face Earth.
Orion took the snapshot around its maximum distance from Earth of 268,563 miles. That's the farthest any human-oriented spacecraft has traveled, beating even Apollo 13's record of 248,655 miles ...
It is usually quoted as "light-time for unit distance" in tables of astronomical constants, and its currently accepted value is 499.004 786 385(20) s. [3] [4] The mean diameter of Earth is about 0.0425 light-seconds. The average distance between Earth and the Moon (the lunar distance) is about 1.282 light-seconds.
Every 18.6 years, the angle between the Moon's orbit and Earth's equator reaches a maximum of 28°36′, the sum of Earth's equatorial tilt (23°27′) and the Moon's orbital inclination (5°09′) to the ecliptic. This is called major lunar standstill. Around this time, the Moon's declination will vary from −28°36′ to +28°36′.
The percentage columns show the distance from the orbit compared to the semimajor axis. E.g. for the Moon, L 1 is 326 400 km from Earth's center, which is 84.9% of the Earth–Moon distance or 15.1% "in front of" (Earthwards from) the Moon; L 2 is located 448 900 km from Earth's center, which is 116.8% of the Earth–Moon distance or 16.8% ...
380 Earth radii (very inaccurate, true=16000 Earth radii) Aristarchus of Samos made a measurement of the distance of the Sun from the Earth in relation to the distance of the Moon from the Earth. The distance to the Moon was described in Earth radii (20, also inaccurate). The diameter of the Earth had been calculated previously.