Earth Fact Sheet


[Global view of Earth]

Bulk parameters

Mass (1024 kg)                 5.9736
Volume (1010 km3)             108.321   
Equatorial radius (km)	        6378    
Polar radius (km)               6356         
Volumetric mean radius (km)     6371
Core radius (km)                3485
Ellipticity                    0.0034       
Mean density (kg/m3)            5520      
Surface gravity (m/s2)          9.78      
Escape velocity (km/s)         11.186
GM (x 106 km3/s2)               0.3986      
Bond albedo                     0.385  
Visual geometric albedo         0.367
Visual magnitude V(1,0)        -3.86
Solar irradiance (W/m2)         1380     
Black-body temperature (K)       247.3    
Topographic range (km)            20
Moment of inertia (I/MR2)       0.3308
J2 (x 10-6)                    1082.63      

Orbital parameters

Semimajor axis (106 km)         149.6     
Sidereal orbit period (days)    365.256
Tropical orbit period (days)    365.242    
Perihelion (106 km)             147.1         
Aphelion (106 km)               152.1
Mean orbital velocity (km/s)     29.79        
Orbit inclination (deg)           0.00      
Orbit eccentricity                0.0167     
Sidereal rotation period (hrs)   23.9345    
Equatorial inclination (deg)     23.44     

Terrestrial Magnetosphere

    Dipole field strength: 0.3076 gauss-Re3
    Latitude/Longitude of dipole N: 78.6 degrees N/70.1 degrees W
    Dipole offset (planet center to dipole center) distance: 0.0725 Re
    Latitude/Longitude of offset vector: 18.3 degrees N/147.8 degrees E

Note: Re denotes Earth radii, 6,378 km


Terrestrial Atmosphere


Surface Pressure: 1014 mb
Surface Density: 1.217 kg/m3 
Scale height: 8.5 km
Average temperature:  288 K
Diurnal temperature range: 283 K to 293 K
Wind speeds: 0 to 100 m/s
Mean molecular weight: 28.97 g/mole 
Atmospheric composition (by volume, dry air): 
    Major      : 78.084% Nitrogen (N2), 20.946% Oxygen (O2), 
    Minor (ppm): Argon (Ar) - 9340; Carbon Dioxide (CO2) - 350
                 Neon (Ne) - 18.18; Helium (He) - 5.24; CH4 - 1.7
                 Krypton (Kr) - 1.14; Hydrogen (H2) - 0.55 
    Water is highly variable, typically makes up about 1%

The Moon

For information on the Moon, see the Moon 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 notes on the sub- and superscripts.

* Notes on the factsheets - definitions of parameters, units, notes on sub- and superscripts, etc.


* Earth Page
* Directory to other Planetary Fact Sheets
* NSSDC Planetary Home Page
For more information about planetary data at NSSDC, please contact:
Dr. David R. Williams, dwilliams@nssdca.gsfc.nasa.gov, (301) 441-4197
Hughes STX Corporation, NSSDC Project, 7701 Greenbelt Rd., Suite 400, Greenbelt, MD 20770 USA
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NASA Official: J. H. King, king@nssdca.gsfc.nasa.gov
Last Updated: 06 March 1996, DRW