Moon in culture

Moon

Full moon as seen from Earth's Northern Hemisphere
Designations
Adjectives
Orbital characteristics
Perigee	362600 km (356400–370400 km)
Apogee	405400 km (404000–406700 km)
Semi-major axis	7008384399000000000♠384399 km  (7008384466527698999♠0.00257 AU)
Eccentricity	6998549000000000000♠0.0549
Orbital period	7006236059151040000♠27.321661 d (27 d 7 h 43 min 11.5 s)
Synodic period	7006255144288960000♠29.530589 d (29 d 12 h 44 min 2.9 s)
Average orbital speed	7003102200000000000♠1.022 km/s
Inclination	5.145° to the ecliptic
Longitude of ascending node	Regressing by one revolution in 18.61 years
Argument of perigee	Progressing by one revolution in 8.85 years
Satellite of	Earth
Physical characteristics
Mean radius	7006173710000000000♠1737.1 km  (0.273 of Earth's)
Equatorial radius	7006173810000000000♠1738.1 km  (0.273 of Earth's)
Polar radius	7006173600000000000♠1736.0 km  (0.273 of Earth's)
Flattening	6997119999999999999♠0.0012
Circumference	7007109210000000000♠10921 km  (equatorial)
Surface area	7013379300000000000♠3.793×107 km2  (0.074 of Earth's)
Volume	7019219580000000000♠2.1958×1010 km3  (0.020 of Earth's)
Mass	7022734200000000000♠7.342×1022 kg  (6998123000000000000♠0.012300 of Earth's)
Mean density	7003334400000000000♠3.344 g/cm3 6999606000000000000♠0.606 × Earth
Surface gravity	7000162000000000000♠1.62 m/s2  (6999165400000000000♠0.1654 g)
Moment of inertia factor	6999392900000000000♠0.3929±0.0009
Escape velocity	7003238000000000000♠2.38 km/s
Sidereal rotation period	7006236059151040000♠27.321661 d  (synchronous)
Equatorial rotation velocity	4.627 m/s
Axial tilt	1.5424° to ecliptic 6.687° to orbit plane
Albedo	0.136
Surface temp. min mean max Equator 100 K 220 K 390 K 85°N  150 K 230 K
Apparent magnitude	−2.5 to −12.9 −12.74  (mean full moon)
Angular diameter	29.3 to 34.1 arcminutes
Atmosphere
Surface pressure	10−7Pa (1 picobar)  (day) 10−10 Pa (1 femtobar)   (night)
Composition by volume	He Ar Ne Na K H Rn

The Moon is an astronomical body that orbits planet Earth, being Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits (its primary). Following Jupiter's satellite Io, the Moon is second-densest satellite among those whose densities are known.

The Moon is thought to have formed about 4.51 billion years ago, not long after Earth. The most widely accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars-sized body called Theia.

The Moon is in synchronous rotation with Earth, always showing the same face, with its near side marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters. As seen from the Earth, it is the second-brightest regularly visible celestial object in Earth's sky, after the Sun. Its surface is actually dark, although compared to the night sky it appears very bright, with a reflectance just slightly higher than that of worn asphalt. Its gravitational influence produces the ocean tides, body tides, and the slight lengthening of the day.