Properties of the Moon and the Earth-Moon system

▪ Table

Properties of the Moon and the Earth-Moon system

Moon Earth approximate ratio (Moon to Earth)

mean distance from Earth (orbital radius) 384,400 km — —

period of orbit around Earth (sidereal period of revolution) 27.3217 Earth days — —

inclination of equator to ecliptic plane (Earth's orbital plane) 1.53° 23.45° —

inclination of equator to body's own orbital plane (obliquity to orbit) 6.68° 23.45° —

inclination of orbit to Earth's Equator 18.28°-28.58° — —

eccentricity of orbit around Earth 0.0549 — —

recession rate from Earth 3.8 cm/year — —

rotation period synchronous with orbital period 23.9345 hr —

equatorial radius 1,738 km 6,378 km 1:4

surface area 37,900,000 km² 510,066,000 km² (land area, 148,000,000 km²) 1:14

mass 0.0735 × 10²⁴ kg 5.976 × 10²⁴ kg 1:81

mean density 3.34 g/cm³ 5.52 g/cm³ 1:1.7

mean surface gravity 162 cm/sec² 980 cm/sec² 1:6

escape velocity 2.38 km/sec 11.2 km/sec 1:5

mean surface temperature day, 380 K (224 °F, 107 °C); night, 120 K (-244 °F, -153 °C) 288 K (59 °F, 15 °C) —

temperature extremes 396 K (253 °F, 123 °C) to 40 K (-388 °F, -233 °C) 331 K (136 °F, 58 °C) to 184 K (-128 °F, -89 °C) —

surface pressure 3 × 10^-15 bar 1 bar 1:300 trillion

atmospheric molecular density day, 10⁴ molecules/cm³; night, 2 × 10⁵ molecules/cm³ 2.5 × 10¹⁹ molecules/cm³ (at standard temperature and pressure) about

1:100 trillion

average heat flow 29 mW/m² 63 mW/m² 1:2.2

See as table:

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