Earth Fact Sheet


[Global view of Earth]

Bulk parameters

Mass (1024 kg)                 5.9726
Volume (1010 km3)             108.321   
Equatorial radius (km)	        6378.1    
Polar radius (km)               6356.8         
Volumetric mean radius (km)     6371.0
Core radius (km)                3485
Ellipticity (Flattening)        0.00335      
Mean density (kg/m3)            5514      
Surface gravity (m/s2)          9.798  
Surface acceleration (m/s2)     9.780        
Escape velocity (km/s)         11.186
GM (x 106 km3/s2)               0.3986      
Bond albedo                     0.306  
Visual geometric albedo         0.367
Visual magnitude V(1,0)        -3.86
Solar irradiance (W/m2)         1367.6    
Black-body temperature (K)       254.3    
Topographic range (km)            20
Moment of inertia (I/MR2)       0.3308
J2 (x 10-6)                    1082.63      
Number of natural satellites       1          
Planetary ring system             No 

Orbital parameters

Semimajor axis (106 km)         149.60    
Sidereal orbit period (days)    365.256
Tropical orbit period (days)    365.242    
Perihelion (106 km)             147.09        
Aphelion (106 km)               152.10
Mean orbital velocity (km/s)     29.78        
Max. orbital velocity (km/s)     30.29
Min. orbital velocity (km/s)     29.29
Orbit inclination (deg)           0.000     
Orbit eccentricity                0.0167     
Sidereal rotation period (hrs)   23.9345    
Length of day (hrs)              24.0000
Obliquity to orbit (deg)         23.44     

Earth Mean Orbital Elements (J2000)

Semimajor axis (AU)                  1.00000011  
Orbital eccentricity                 0.01671022   
Orbital inclination (deg)            0.00005  
Longitude of ascending node (deg)  -11.26064  
Longitude of perihelion (deg)      102.94719  
Mean Longitude (deg)               100.46435

North Pole of Rotation

Right Ascension:  0.00 - 0.641T
Declination    : 90.00 - 0.557T
Reference Date : 12:00 UT 1 Jan 2000 (JD 2451545.0)
T = Julian centuries from reference date 

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
Total mass of atmosphere:  5.1 x 1018 kg
Total mass of hydrosphere:  1.4 x 1021 kg
Average temperature:  288 K (15 C)
Diurnal temperature range: 283 K to 293 K (10 to 20 C)
Wind speeds: 0 to 100 m/s
Mean molecular weight: 28.97 g/mole 
Atmospheric composition (by volume, dry air): 
    Major      : 78.08% Nitrogen (N2), 20.95% Oxygen (O2), 
    Minor (ppm): Argon (Ar) - 9340; Carbon Dioxide (CO2) - 400
                 Neon (Ne) - 18.18; Helium (He) - 5.24; CH4 - 1.7
                 Krypton (Kr) - 1.14; Hydrogen (H2) - 0.55 
    Numbers do not add up to exactly 100% due to roundoff and uncertainty
    Water is highly variable, typically makes up about 1%

The Moon

For information on the Moon, see the Moon Fact Sheet
bullet Notes on the factsheets - definitions of parameters, units, notes on sub- and superscripts, etc.

bullet Planetary Fact Table - metric units
bullet Planetary Fact Table - U.S. units
bullet Planetary Fact Table - Earth ratio


bullet Earth Page
bullet Directory to other Planetary Fact Sheets

[NASA Logo]
Author/Curator:
Dr. David R. Williams, dave.williams@nasa.gov
NSSDC, Mail Code 690.1
NASA Goddard Space Flight Center
Greenbelt, MD 20771
+1-301-286-1258


NASA Official: Ed Grayzeck, edwin.j.grayzeck@nasa.gov
Last Updated: 01 July 2013, DRW