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<title>Uranus Fact Sheet</title>
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<h3>Uranus Fact Sheet</h3>
<img src="../images/uranus">Uranus
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<h4>Uranus/Earth Comparison</h4>

<h5>Bulk parameters</h5>
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                                    Uranus      Earth   Ratio(Uranus/Earth)
Mass (10<sup>24</sup> kg)                      86.83       5.9736        14.536
Volume (10<sup>10</sup> km<sup>3</sup>)                    6,833    108.321         63.08
Radius (1 bar level) (km)
    Equatorial                      25,559      6,378          4.007
    Polar                           24,973      6,356          3.929
Volumetric mean radius (km)         25,362      6,371          3.981
Ellipticity                          0.023      0.0034         6.76
Mean density (kg/m<sup>3</sup>)                 1,318      5,520          0.239
Gravity (eq., 1 bar) (m/s<sup>2</sup>)          8.69       9.78           0.889
Escape velocity (km/s)              21.3       11.19           1.903
GM (x 10<sup>6</sup> km<sup>3</sup>/s<sup>2</sup>)                    5.794      0.3986        14.536
Bond albedo                          0.90       0.385          2.338
Visual geometric albedo              0.51       0.367          1.390
Visual magnitude V(1,0)             -7.19      -3.86             -
Solar irradiance (W/m<sup>2</sup>)              3.71       1,380          0.0027
Black-body temperature (K)          35.9      247.3            0.145
Moment of inertia (I/MR<sup>2</sup>)            0.225      0.3308         0.680
J<sub>2</sub> (x 10<sup>-6</sup>)                       3343.43    1082.63           3.088    
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<h5>Orbital parameters</h5> 
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                                    Uranus      Earth   Ratio(Uranus/Earth)
Semimajor axis (10<sup>6</sup> km)            2,869.6       149.6        19.182
Sidereal orbit period (days)      30,685.4       365.256      84.011   
Tropical orbit period (days)      30,588.740     365.242      83.749
Perihelion (10<sup>6</sup> km)                2,734.0       147.1        18.59      
Aphelion (10<sup>6</sup> km)                  3,005.2       152.1        19.76
Synodic period (days)                369.66        -             -
Mean orbital velocity (km/s)           6.82       29.79        0.229
Orbit inclination (deg)                0.773       0.00          -
Orbit eccentricity                     0.04724     0.0167      2.829
Sidereal rotation period (hours)      17.24*      23.9345      0.720
Obliquity to orbit (deg)              97.86       23.45        4.173
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* Magnetic coordinates (as determined by the Voyager 2 Radio Science experiment)
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<h4>Uranian Magnetosphere</h4>

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    Dipole field strength: 0.228 gauss-Ru<sup>3</sup>
    Dipole tilt to rotational axis: 58.6 degrees
    Dipole offset (planet center to dipole center) distance: 0.3 Ru along the rotation axis
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<b>Note:</b> Ru denotes Uranian radii, here defined to be 25,600 km
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<h4>Uranian Atmosphere</h4>
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Surface Pressure: &gt;&gt;100 bars  
Average temperature: ~58 K
Temperature at 1 bar: ~76 K
Density at 1 bar: ~0.42 kg/m<sup>3</sup>
Wind speeds: 0-200 m/s
Scale height: 27.7 km
Mean molecular weight: 2.64 g/mole
Atmospheric composition
    Major:       Molecular hydrogen (H<sub>2</sub>) - 89%; Helium (He) - 11%
    Minor (ppm): Methane (CH<sub>4</sub>)
    Aerosols:    Ammonia ice, water ice, ammonia hydrosulfide, methane ice(?)
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