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Detailed Moon Statistics
Moon / Earth Comparisons
Bulk Parameters
|
Moon
|
Earth
|
Ratio (Moon/Earth)
|
Mass (1024 kg)
|
0.07349
|
5.9736
|
0.0123
|
Volume (1010 km3)
|
2.1968
|
108.321
|
0.0203
|
Equatorial radius (km)
|
1737.4
|
6378.1
|
0.2724
|
Polar radius (km)
|
1737.4
|
6356.8
|
0.2733
|
Volumetric mean radius (km)
|
1737.4
|
6371.0
|
0.2727
|
Ellipticity (Flattening)
|
0.000
|
0.00335
|
0.0
|
Mean density (kg/m3)
|
3340
|
5515
|
0.605
|
Surface gravity (m/s2)
|
1.62
|
9.78
|
0.166
|
Escape velocity (km/s)
|
2.38
|
11.2
|
0.213
|
GM (x 106 km3/s2)
|
0.0049
|
0.3986
|
0.0123
|
Bond albedo
|
0.11
|
0.306
|
0.360
|
Visual geometric albedo
|
0.12
|
0.367
|
0.330
|
Visual magnitude V(1,0)
|
+0.21
|
-3.86
|
-
|
Solar irradiance (W/m2)
|
1367.6
|
1367.6
|
1.000
|
Black-body temperature (K)
|
274.5
|
254.3
|
1.079
|
Topographic range (km)
|
16
|
20
|
0.800
|
Moment of inertia (I/MR2)
|
0.394
|
0.3308
|
1.191
|
J2 (x 10-6)
|
202.7
|
1082.63
|
0.187
|
Orbital parameters for the Moon (for orbit about the Earth)
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) 1.023
Max. orbital velocity (km/s) 1.076
Min. orbital velocity (km/s) 0.964
Orbit inclination (deg) 5.145
Orbit eccentricity 0.0549
Sidereal rotation period (hrs) 655.728
Equatorial inclination (deg) 6.68
Recession rate from Earth (cm/yr) 3.8
Mean values at opposition from Earth
Distance from Earth (km) 384,467
Apparent diameter (seconds of arc) 1864.2
Apparent visual magnitude -12.74
Lunar Atmosphere
Diurnal temperature range: >100 K to <400 K (roughly -173 C to +227 C)
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 (particles per cubic cm):
4He - 40,000 ; 20Ne - 40,000 ; H2 - 35,000
40Ar - 30,000 ; 22Ne - 5,000 ; 36Ar - 2,000
Methane - 1000 ; Ammonia - 1000 ; CO2 - 1000
Trace O+, Al+, Si+
Possible P+, Na+, Mg+
Composition of the tenuous lunar atmosphere is poorly known and variable;
these are estimates of the upper limits of the night time ambient atmosphere
composition. Daytime levels are difficult to measure due to heating and
outgassing of Apollo surface experiments (Detailed Earth Statistics)
