DK Science: Venus
Venus is only a little smaller than Earth, is made up of rock, and has an atmosphere, but it is otherwise quite unlike our planet. Its surface is covered with volcanoes, the atmosphere is crushing, and the temperature is hotter than an oven. Venus completes its orbit in 225 Earth days, but turns slowly, taking 243 Earth days to rotate once. This means that a day on Venus is longer than its year.
Table 10. ESSENTIAL DATA
| Diameter at equator | 12,104 km (7,521 miles) |
| Average distance from Sun | 108.2 million km (67.2 million miles) |
| Orbital period | 224.7 days |
| Rotation period | 243 days |
| Mass (Earth=1) | 0.82 |
| Gravity (Earth=1) | 0.9 |
| Average surface temperature | 464°C (867°F) |
| Number of moons | 0 |
Maat Mons is one of the largest volcanoes on Venus. Around 200 km (125 miles) across, it rises 9 km (5 1/2 miles) in height. Probably extinct, it has erupted repeatedly in the past, spewing out vast quantities of runny lava that formed the surrounding volcanic plains.
The atmosphere of Venus is much thicker than that of Earth and is made up mostly of carbon dioxide. Its pressure is nearly 100 times Earth’s atmospheric pressure. The dense clouds in the atmosphere are made up of sulphuric acid droplets. The atmosphere traps heat like a greenhouse, sending the temperature soaring to more than 475°C (900°F).
