Venus, the second planet in order of distance from the Sun,
is almost a twin of the Earth in size and mass; it is only
very slightly smaller and less dense. However, in all other
respects it is quite unlike the Earth. Only during the past
40 years have we been able to find out what Venus is really
like; its surface is permanently hidden by its thick, cloudy
atmosphere, and before the Space Age Venus was often
referred to as ‘the planet of mystery’

Venus Data:

Distance from the Sun:
mean 108.2 million km = 0.723 a.u.
max 109.0 million km = 0.728 a.u.
min 107.4 million km = 0.718 a.u.
Sidereal period: 224.701 days
Synodic period: 583.9 days
Rotation period: 243.018 days
Mean orbital velocity: 35.0 kms−1
Axial inclination: 177◦
.33
Orbital inclination: 3◦2339
.8
Orbital eccentricity: 0.0167
Diameter: 12.104 km
Oblateness: negligible
Apparent diameter from Earth:
mean 37
.3
max 65
.2
min 9
.5
Mass: 4.868 × 1024 kg
Reciprocal mass, Sun = 1: 408.520
Mass, Earth = 1: 0.815
Density, water = 1: 5.25
Volume, Earth = 1: 0.86
Escape velocity: 10.36 km s−1
Surface gravity, Earth = 1: 0.909
Mean surface temperature:
cloud tops −33 ◦C
surface 467 ◦C
Albedo: 0.76
Maximum magnitude: −4.4
Mean diameter of Sun, as seen from Venus: 4415.