Venus/Earth Comparison

Bulk parameters

                                   Venus          Earth     Ratio (Venus/Earth)
Mass (1024 kg)                      4.869          5.9736         0.815
Volume (1010 km3)                  92.843        108.321          0.857
Equatorial radius (km)	           6052           6378            0.949
Polar radius (km)                  6052           6356            0.952
Volumetric mean radius (km)        6052           6371            0.950
Ellipticity                         0.000          0.0034         0.0
Mean density (kg/m3)               5204           5520            0.943
Surface gravity (eq.) (m/s2)        8.87           9.78           0.907
Escape velocity (km/s)             10.36          11.19           0.926
GM (x 106 km3/s2)                   0.3249         0.3986         0.815
Bond albedo                         0.72           0.385          1.87
Visual geometric albedo             0.65           0.367          1.77
Visual magnitude V(1,0)            -4.40          -3.86             -
Solar irradiance (W/m2)            2660           1380            1.928
Black-body temperature (K)          238.9          247.3          0.966
Topographic range (km)               15             20            0.750
Moment of inertia (I/MR2)           0.33           0.3308         0.998
J2 (x 10-6)                         4.458       1082.63           0.004

Orbital parameters

                                   Venus           Earth     Ratio (Venus/Earth)
Semimajor axis (106 km)           108.2           149.6           0.723
Sidereal orbit period (days)      224.701         365.256         0.615
Tropical orbit period (days)      224.695         365.242         0.615
Perihelion (106 km)               107.5           147.1           0.731
Aphelion (106 km)                 108.9           152.1           0.716
Synodic period (days)             583.92            -               -
Mean orbital velocity (km/s)       35.02           29.79          1.176
Orbit inclination (deg)             3.39            0.00            -
Orbit eccentricity                  0.0068          0.0167        0.407
Sidereal rotation period (hrs)   5832.5            23.9345        243.7
Obliquity to orbit (deg)          177.3            23.45         (0.115)  

Venus Observational Parameters

Discoverer:      Unknown
Discovery Date:  Prehistoric

Apparent diameter from Earth
        Maximum (seconds of arc)    66.0
        Minimum (seconds of arc)     9.7
Distance from Earth
        Minimum (106 km)            38.2
        Maximum (106 km)           261.0
Apparent magnitude near opposition  -4.4      

Venus Mean Orbital Elements (J2000)

Semimajor axis (AU)                  0.72333199
Orbital eccentricity                 0.00677323
Orbital inclination (deg)            3.39471
Longitude of ascending node (deg)   76.68069
Longitude of perihelion (deg)      131.53298
Mean Longitude (deg)               181.97973

Venus Atmosphere

Surface Pressure: 92 bars
Surface Density: ~65. kg/m3
Scale height: 15.9 km
Average temperature: 737 K
Diurnal temperature range: ~0
Wind speeds: 0.3 to 1.0 m/s (surface)
Mean molecular weight: 43.45 g/mole
Atmospheric composition (near surface, by volume):
    Major:       96.5% Carbon Dioxide (CO2), 3.5% Nitrogen (N2)
    Minor (ppm): Sulfur Dioxide (SO2) - 150; Argon (Ar) - 70; Water (H2O) - 20;
                 Carbon Monoxide (CO) - 17; Helium (He) - 12; Neon (Ne) - 7