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Venus’ cloud shroud
Venus is covered by a thick layer of clouds. These clouds are made mostly of sulfuric acid and are very fast moving, going up to 220 miles per hour (350 km per hour). The clouds rotate 60 times faster than the planet rotates. The clouds circle Venus in four Earth days; the planet rotates around its axis in 243 Earth days. These quickly-moving clouds distribute the heat around the planet, making the night side hot also. V-shaped cloud patterns are visible in the middle latitudes when the clouds are examined in ultraviolet light.
The clouds rain sulfuric acid (extremely acid rain), but this corrosive precipitation does not reach the surface. The high heat beneath the clouds (up to 220°C) evaporates the rain drops about 10 miles (30 km) above Venus.
Atmosphere
Venus’ atmosphere is mostly gaseous carbon dioxide (96%). The remaining components are: 3% nitrogen and 0.003% water vapor. Venus may have had a lot of water sometime in the past, but it probably boiled away in Venus’ high temperatures.
The atmospheric pressure on Venus is enormous, about 90 times greater than the atmospheric pressure on the Earth’s surface.
The greenhouse effect traps heat in the atmosphere. The thick carbon dioxide atmosphere lets very little infrared radiation escape into space; most is reflected back to the planet.