| Bulk
Parameters |
Earth |
Moon |
Ratio
(Moon/Earth) |
| Mass
(1024 kg) |
5.9736 |
0.07349 |
0.0123 |
| Volume
(1010 km3) |
108.321 |
2.1968 |
0.0203 |
| Equatorial
Radius (km) |
6378.1 |
1737.4 |
0.2724 |
| Polar
radius (km) |
6356.8 |
1737.4 |
0.2733 |
| Volumetric
mean radius (km) |
6371.0 |
1737.4 |
0.2727 |
| Core
radius (km) |
3485 |
- |
- |
| Ellipticity |
0.000 |
0.00335 |
0.0 |
| Mean
density (kg/m3) |
5515 |
3340 |
0.605 |
| Surface
gravity (eq.) (m/s2) |
9.78 |
1.62 |
0.166 |
| Escape
velocity (km/s) |
11.186 |
2.38 |
0.213 |
| GM
(x 106 km3/s2) |
0.3986 |
0.0049 |
0.0123 |
| Bond
albedo |
0.306 |
0.0049 |
0.360 |
| Visual
geometric albedo |
0.367 |
0.12 |
0.330 |
| Visual
magnitude V (1,0) |
-3.86 |
+0.21 |
- |
| Solar
irradiance (W/m2) |
1367.6 |
1367.6 |
1.000 |
| Black-body
temperature (K) |
254.3 |
274.5 |
1.079 |
| Topographic
range (km) |
20 |
16 |
0.800 |
| Moment
of inertia (I/MR2) |
0.3308 |
0.394 |
1.191 |
| J2
(x 10-6) |
1082.63 |
202.7 |
0.187 |
| Orbital
Parameters |
Earth |
Moon |
|
| Semimajor
axis (106 km) |
149.60 |
0.3844 |
|
| Sidereal
orbit period (days) |
365.256 |
Perigee
(106 km ): 0.3844 |
| Tropical
orbit period (days) |
365.242 |
Apogee
(106 km): 0.4055 |
| Perihelion
(106 km) |
147.09 |
Revolution
period (days): 27.3217 |
| Aphelion
(106 km) |
152.10 |
Recession
rate from Earth (cm/yr): 3.8 |
| Synodic
period (days) |
|
29.53 |
|
| Mean
orbital velocity (km/s) |
29.78 |
1.023 |
|
| Max.
orbital velocity (km/s) |
30.29 |
1.076 |
|
| Min.
orbital velocity (km/s) |
29.29 |
0.964 |
|
| Orbital
inclination (deg) |
0.000 |
5.145 |
|
| Orbit
eccentricity |
0.0167 |
0.0549 |
|
| Sidereal
rotation period (hrs) |
23.9345 |
655.728 |
|
| Length
of day (hrs) |
24.000 |
|
|
| Obliquity
to orbit (deg) |
23.45 |
Equatorial
inclination (deg): 6.68 |
|
| Moon
Observational
Parameters |
|
|
|
| Mean
values at opposition from Earth: |
Distance
from Earth (km): 384,467 |
Apparent
diameter (seconds of arc): 1864.2 |
Apparent
visual magnitude: -12.74 |
| Mean Orbital Elements
(J200) |
Earth |
|
|
| Semimajor
axis (A.U.) |
1.00000011 |
|
|
| Orbital
eccentricity |
0.01671022 |
|
|
| Orbital
inclination (deg) |
0.00005 |
|
|
| Longitude
of ascending node |
-11.26064 |
|
|
| Longitude
of perihelion (deg) |
102.94719 |
|
|
| Mean
Longitude (deg) |
100.46435 |
|
|
| Magnetosphere |
Earth |
|
|
| Dipole
field strength |
0.3076
gauss - Re3 |
|
|
| latitude/longitude
of dipole N: |
78.6
degrees N, 70.1 degrees W |
|
| Dipole
offset distance: |
(planet
center to dipole center): 0.0725 Re |
|
| latitude/longitude
of offset vector: |
18.3
degrees N, 147.8 degrees E |
|
| Atmosphere |
Earth |
Moon |
| Surface
Pressure |
1014
millibars |
at
night: 3x 10-15 bar (2x 10-12 torr) |
| Surface
Density |
1.217
kg/m3 |
Total
mass of atmosphere: ~25000 kg |
| Scale
Height |
8.5
km |
Abundance
at surface: 2 x 1015 particles/cm3 |
| Average
temperature |
288
K |
|
| Diurnal
temperature range |
283
K to 293 K |
>100K
to <400 K (roughly -250 F to +250 F) |
| Wind
speeds |
0
to 100 m/s |
|
| Mean
molecular weight |
28.97
g/mole |
|
| Atmospheric
Composition: |
Nitrogen
- 78.084% |
Moon:
(particles per cubic cm): |
| |
Oxygen
20.946% |
Helium-
40,000 |
Neon
(40) - 40,000 |
| Minor
(ppm): |
Argon
- 9340 |
Hydrogen-
35,000 |
Argon(40)-
30,000 |
| |
Carbon
Dioxide - 350 |
Neon(22)-
5,000 |
Argon(36)-
2,000 |
| |
Neon
- 18.18 |
Methane-
1000 |
Ammonia-1000 |
| |
Helium
- 5.24 |
Carbon
dioxide- 1000 |
|
| |
Methane
- 1.7 |
Trace
amounts of: Oxygen, Aluminum, Silicon |
| |
Krypton
- 1.14 |
Possible:
Potassium, Sodium, Mg |
| |
Hydrogen
- 0.55 |
Composition
of 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
instruments. |
| |
Water-
Highly variable, about 1% |
