average distance between earth and moon in km
Lunar distance (astronomy) Lunar distance (LD or   Δ ⊕ L   {\textstyle \Delta _{\oplus L}} ), also called Earth–Moon distance, Earth–Moon characteristic distance, or distance to the Moon, is a unit of measure in astronomy. It is the average distance from the center of Earth to the center of the Moon. More technically, it is the mean semi-major axis of the geocentric lunar orbit. It may also refer to the time-averaged distance between the centers of the Earth and the Moon, or less commonly, the instantaneous Earth–Moon distance. The lunar distance is approximately a quarter of a million miles (7008400000000000000♠400000 km).[1]