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<title>Earth Fact Sheet</title>
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<h3>Earth Fact Sheet</h3>
<img src="../images/earth">Earth
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<h5>Bulk parameters</h5>
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Mass (10<sup>24</sup> kg)                 5.9736
Volume (10<sup>10</sup> km<sup>3</sup>)             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/m<sup>3</sup>)            5520      
Surface gravity (m/s<sup>2</sup>)          9.78      
Escape velocity (km/s)         11.186
GM (x 10<sup>6</sup> km<sup>3</sup>/s<sup>2</sup>)               0.3986      
Bond albedo                     0.385  
Visual Geometric Albedo         0.367
Visual magnitude V(1,0)        -3.86
Solar irradiance (W/m<sup>2</sup>)         1380     
Black-body temperature (K)       247.3    
Topographic range (km)            20
Moment of inertia (I/MR<sup>2</sup>)       0.3308
J<sub>2</sub> (x 10<sup>-6</sup>)                    1082.63      
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<h5>Orbital parameters</h5> 
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Semimajor axis (10<sup>6</sup> km)         149.6     
Sidereal orbit period (days)    365.256
Tropical orbit period (days)    365.242    
Perihelion (10<sup>6</sup> km)             147.1         
Aphelion (10<sup>6</sup> 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    
Obliquity to orbit (deg)         23.45     
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<h4>Terrestrial Magnetosphere</h4>

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    Dipole field strength: 0.3076 gauss-Re<sup>3</sup>
    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
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<b>Note:</b> Re denotes Earth radii, 6,378 km
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<h4>Terrestrial Atmosphere</h4>
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Surface Pressure: 1014 mb
Surface Density: 1.217 kg/m<sup>3</sup> 
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 (N<sub>2</sub>), 20.946% Oxygen (O<sub>2</sub>), 
    Minor (ppm): Argon (Ar) - 9340; Carbon Dioxide (CO<sub>2</sub>) - 350
                 Neon (Ne) - 18.18; Helium (He) - 5.24; CH<sub>4</sub> - 1.7
                 Krypton (Kr) - 1.14; Hydrogen (H<sub>2</sub>) - 0.55 
    Water is highly variable, typically makes up about 1%
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