| Orbital Elements | ||
| Mean distance from Sun | 108,200,000 km | = 0.7233 astronomical unit |
| Perihelion distance | 107,480,000 km | = 0.7185 astronomical unit |
| Aphelion distance | 108,940,000 km | = 0.7282 astronomical unit |
| Eccentricity of orbit | 0.0068 | |
| Inclination of orbit | 3.394° | relative to Earth's orbit |
| Period of orbit | 224.7 days | |
| Synodic period | 583.92 days | relative to Earth |
| Mean orbital speed | 35.02 km/s | |
| Minimum orbital speed | 34.79 km/s | |
| Maximum orbital speed | 35.26 km/s | |
| Physical Properties | ||
| ||
| Diameter | 12,103.6 km | = 0.9499 Earth diameter |
| Radius | 6,051.8 km | |
| Mass | 4.8685 x 1024 kg | = 0.8152 Earth mass |
| Mean density | 5.25 g/cm3 | |
| Rotational period | 243.0185 days | |
| Length of day | 116.75 days | |
| Inclination of axis | 177.36° | relative to the axis of its orbit |
| Gravity at surface | 8.87 m/s2 | |
| Escape speed | 10.36 km/s | from cloud tops |
| Visual geometric albedo | 0.65 | |
| Visual magnitude (Vo) | -4.4 | maximum, as seen from Earth |
| Mean surface temperature | 464°C | |
| Atmospheric pressure | 92 bars | |
| Atmosphere composition near surface, by volume | ||
| ||
| Carbon dioxide (CO2) | 96.5% | |
| Nitrogen (N) | 3.5% | |
| Sulfur dioxide (SO2) | 150 ppm | |
| Argon (Ar) | 70 ppm | |
| Water vapor (H2O) | 20 ppm | |
| Carbon monoxide (CO) | 17 ppm | |
| Helium (He) | 12 ppm | |
| Neon (Ne) | 7 ppm | |
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for more about the Solar System
Jeff Root
September 4, 2003