Mass (kg)........................................... 3.3 x 10^23
Diameter (km)....................................... 4878
Mean density (kg/m^3) .............................. 5420
Escape velocity (m/sec)............................. 4300

Average distance from Sun (AU)...................... 0.387
Rotation period (length of day) (in Earth days)..... 58.65
Revolution period (length of year) (in Earth days).. 87.97

Obliquity (tilt of axis) (degrees).................. 0
Orbit inclination (degrees)......................... 7
Orbit eccentricity.................................. 0.206

Mean surface temperature (K)........................ 452
Maximum surface temperature (K)..................... 700
Minimum surface temperature (K)..................... 100

Visual geometric albedo............................. 0.12
Largest known surface feature....................... Caloris Basin 
                                                (1350 km diameter)
Atmospheric components.............................. trace amounts of 
                                                     hydrogen and 
                                                     helium
Surface materials................................... basaltic and 
                                                     anorthositic rocks 
                                                     and regolith