- MEAN RADIUS: 6051.9 km
- MASS: 0.814 (Earth=1)
- DENSITY: 5.24 (g/cm^3)
- GRAVITY: 0.903 (Earth=1)
- ORBIT PERIOD: 224.7 (Earth days)
- ROTATION PERIOD: 243.0 R (Earth days)
- SEMIMAJOR AXIS OF ORBIT: 0.723 au
- ECCENTRICITY OF ORBIT: 0.007
On the surface of Venus, the atmospheric pressure is 90 atmospheres. It is composed mostly of carbon dioxide. The surface of the planet is obscured by several layers of clouds many kilometers thick composed of sulfuric acid. This creates a greenhouse effect that brings Venus' surface temperature to over 740 K.
Venus has been called Earth’s sister planet, since it’s fairly close in size (95%), has a density and chemical composition, and has few craters, indicating a similar young age. This led many to believe that there might even be life hidden under the thick layer of clouds. This has since been proven to be impossible.
There are no known satellites of Venus, but between the 1670s and the 1770s, there were several observations of what appeared to be a satellite approximately ¼ the size of Venus. Many theories exist to explain these sightings as well as one in 1892 by E. E. Barnard, including optical illusions, stars, and even a tenth planet, but recent observations have not revealed any satellite.
