Space Book

Venus

 Venus is the second closest planet to the Sun with an average distance of 0.723 AU or 1.082 x 108 km. It takes 224.7 Earth days to orbit the Sun, and rotates retrograde (opposite the direction it orbits) very slowly at a rate of 1 rotation every 243 Earth days. Its mass is 4.868 x 1024 kg or 0.815 Earth masses and it is nearly the same size as Earth with a radius of 0.9488 the Earth's radius. It has no moons, and a very thick atmosphere composed mainly of carbon dioxide. Its surface is extrememly hot with and average temperature of 733 K (460 °C or 860 °F).

Venus can be seen with the naked eye for a few hours before or after sunset, depending on which side of the Sun it is on relative to Earth. It never travels more than 47° from the Sun from our point of view. Scientists are not yet sure whether it has a liquid core, but it does not have a magnetic field.

Venus has many large volcanoes and its atmosphere has evidence of recent volcanic activity. Because of its thick atmosphere which causes a huge greenhouse effect, Venus is the hottest planet in the solar system. The atmosphere also has clouds of concentrated sulfuric acid. Venus seems not to have plate tectonics like Earth does because its crust is too thin and its interior too hot for large plates to form from the crust. Instead it may have flake tectonics where the thin surface crust flakes and crumples.

Many spacecraft, including the Soviet Venera space probes 3-14, and Mariners 2,5 and 10, have flown by or landed on Venus. Most of the spacecraft that landed on Venus lasted only a very short time because of the high pressure and extreme heat.

Venus Factbox
Average distance from Sun 0.723 AU = 1.082 x 108 km = 2.6 million marathons
Number of moons 0
Average orbital speed 35.0 km/s
Orbital period 224.7 days
Rotation period 243.01 days (retrograde)
Inclination of equator to orbit 177.4°
Diameter 12,104 km = 0.949 Earth diameter
Mass 4.868 x 1024 kg = 0.815 Earth mass
Average density 5243 kg/m3
Surface gravity (Earth = 1) 0.91
Albedo 0.59
Average surface temperature 460°C = 860°F = 733 K
Atmosphere 96.5% carbon dioxide, 3.5% nitrogen, 0.003% water vapor