Moon |
Earth |
Ratio (Moon/Earth) |
|
---|---|---|---|
Mass (1024 kg) | 0.07346 | 5.9724 | 0.0123 |
Volume (1010 km3) | 2.1968 | 108.321 | 0.0203 |
Equatorial radius (km) | 1738.1 | 6378.1 | 0.2725 |
Polar radius (km) | 1736.0 | 6356.8 | 0.2731 |
Volumetric mean radius (km) | 1737.4 | 6371.0 | 0.2727 |
Ellipticity (Flattening) | 0.0012 | 0.00335 | 0.36 |
Mean density (kg/m3) | 3344 | 5514 | 0.606 |
Surface gravity (m/s2) | 1.62 | 9.80 | 0.165 |
Surface acceleration (m/s2) | 1.62 | 9.78 | 0.166 |
Escape velocity (km/s) | 2.38 | 11.2 | 0.213 |
GM (x 106 km3/s2) | 0.00490 | 0.39860 | 0.0123 |
Bond albedo | 0.11 | 0.294 | 0.37 |
Geometric albedo | 0.12 | 0.434 | 0.28 |
V-band magnitude V(1,0) | -0.08 | -3.99 | - |
Solar irradiance (W/m2) | 1361.0 | 1361.0 | 1.000 |
Black-body temperature (K) | 270.4 | 254.0 | 1.065 |
Topographic range (km) | 13 | 20 | 0.650 |
Moment of inertia (I/MR2) | 0.394 | 0.3308 | 1.191 |
J2 (x 10-6) | 202.7 | 1082.63 | 0.187 |
Moon |
|
---|---|
Semimajor axis (106 km) | 0.3844 |
Perigee (106 km)* | 0.3633 |
Apogee (106 km)* | 0.4055 |
Revolution period (days) | 27.3217 |
Synodic period (days) | 29.53 |
Mean orbital velocity (km/s) | 1.022 |
Max. orbital velocity (km/s) | 1.082 |
Min. orbital velocity (km/s) | 0.970 |
Inclination to ecliptic (deg) | 5.145 |
Inclination to Earth equator (deg) | 18.28 - 28.58 |
Orbit eccentricity | 0.0549 |
Sidereal rotation period (hrs) | 655.720 |
Obliquity to orbit (deg) | 6.68 |
Recession rate from Earth (cm/yr) | 3.8 |
Mean values at opposition from Earth Distance from Earth (equator, km) 378,000 Apparent diameter (seconds of arc) 1896 Apparent visual magnitude -12.74 * These represent mean apogee and perigee for the lunar orbit, and were used for calculating the maximum and minimum velocities. The orbit changes over the course of the year so the distance from the Moon to Earth roughly ranges from 357,000 km to 407,000 km, giving velocities ranging from 1.100 to 0.966 km/s.
Diurnal temperature range (equator): 95 K to 390 K (~ -290 F to +240 F) Total mass of atmosphere: ~25,000 kg Surface pressure (night): 3 x 10-15 bar (2 x 10-12 torr) Abundance at surface: 2 x 105 particles/cm3 Estimated Composition (night, particles per cubic cm): Helium 4 (4He) - 40,000 ; Neon 20 (20Ne) - 40,000 ; Hydrogen (H2) - 35,000 Argon 40 (40Ar) - 30,000 ; Neon 22 (22Ne) - 5,000 ; Argon 36 (36Ar) - 2,000 Methane - 1000 ; Ammonia - 1000 ; Carbon Dioxide (CO2) - 1000 Trace Oxygen (O+), Aluminum (Al+), Silicon (Si+) Possible Phosphorus (P+), Sodium (Na+), Magnesium (Mg+) Composition of the tenuous lunar atmosphere is poorly known and variable, these are estimates of the upper limits of the nighttime ambient atmosphere composition. Daytime levels were difficult to measure due to heating and outgassing of Apollo surface experiments.For information on the Earth, see the Earth Fact Sheet.