mirrored file at http://SaturnianCosmology.Org/ For complete access to all the files of this collection see http://SaturnianCosmology.org/search.php ========================================================== _________________________________________________________________ Moon Fact Sheet _________________________________________________________________ [1][Global view of Moon] _________________________________________________________________ Moon/Earth Comparison _________________________________________________________________ Bulk parameters Moon Earth Ratio (Moon/Earth) Mass (10^24 kg) 0.07349 5.9736 0.0123 Volume (10^10 km^3) 2.1958 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) 1737.1 6371.0 0.2727 Ellipticity (Flattening) 0.0012 0.00335 0.36 Mean density (kg/m^3) 3350 5515 0.607 Surface gravity (m/s^2) 1.62 9.80 0.165 Surface acceleration (m/s^2) 1.62 9.78 0.166 Escape velocity (km/s) 2.38 11.2 0.213 GM (x 10^6 km^3/s^2) 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/m^2) 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/MR^2) 0.394 0.3308 1.191 J[2] (x 10^-6) 202.7 1082.63 0.187 _________________________________________________________________ Orbital parameters (for orbit about the Earth) Moon Semimajor axis (10^6 km) 0.3844 (radius) Perigee (10^6 km) 0.3633 Apogee (10^6 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 Inclination to ecliptic (deg) 5.145 Inclination to equator (deg) 18.28 - 28.58 Orbit eccentricity 0.0549 Sidereal rotation period (hrs) 655.728 Obliquity to orbit (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 -250 F to +250 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 10^5 particles/cm^3 Estimated Composition (particles per cubic cm): Helium 4 (^4He) - 40,000 ; Neon 20 (^20Ne) - 40,000 ; Hydrogen (H[2]) - 35, 000 Argon 40 (^40Ar) - 30,000 ; Neon 22 (^22Ne) - 5,000 ; Argon 36 (^36Ar) - 2, 000 Methane - 1000 ; Ammonia - 1000 ; Carbon Dioxide (CO[2]) - 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 [2]Earth Fact Sheet. _________________________________________________________________ If no sub- or superscripts appear on this page - for example, if the "Mass" is given in units of "(1024 kg)" - you may want to check the [3]notes on the sub- and superscripts. [4]bullet Notes on the factsheets - definitions of parameters, units, notes on sub- and superscripts, etc. [5]bullet Planetary Fact Table - metric units [6]bullet Planetary Fact Table - U.S. units [7]bullet Planetary Fact Table - Earth ratio _________________________________________________________________ [8]bullet Moon Home Page [9]bullet Directory to other Planetary Fact Sheets [10]bullet NSSDC Planetary Home Page _________________________________________________________________ [NASA Logo] Author/Curator: Dr. David R. Williams, [11]dwilliam at nssdc.gsfc.nasa.gov NSSDC, Mail Code 633 NASA Goddard Space Flight Center Greenbelt, MD 20771 +1-301-286-1258 _________________________________________________________________ NASA Official: Ed Grayzeck, edwin.j.grayzeck at nasa.gov Last Updated: 27 October 2003, DRW References 1. http://nssdc.gsfc.nasa.gov/planetary/image/moonfact_bg.gif 2. http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html 3. http://nssdc.gsfc.nasa.gov/planetary/factsheet/fact_notes.html 4. http://nssdc.gsfc.nasa.gov/planetary/factsheet/fact_notes.html 5. http://nssdc.gsfc.nasa.gov/planetary/factsheet/index.html 6. http://nssdc.gsfc.nasa.gov/planetary/factsheet/planet_table_british.html 7. http://nssdc.gsfc.nasa.gov/planetary/factsheet/planet_table_ratio.html 8. http://nssdc.gsfc.nasa.gov/planetary/planets/moonpage.html 9. http://nssdc.gsfc.nasa.gov/planetary/planetfact.html 10. http://nssdc.gsfc.nasa.gov/planetary/planetary_home.html 11. mailto:dwilliam at nssdc.gsfc.nasa.gov