By Sabine Stanley Ph.D., John Hopkins University
Venus’s surface is a dry desert under a thick atmosphere of mainly carbon dioxide. The temperature is high enough for lead to melt, and the winds in the higher layers of the atmosphere are strong enough to blow away atoms. The active volcanoes send some water vapor in the atmosphere, only to make the clouds more horrible than the hurricanes and lava. Venus is a realization of hell.
Venus is called Earth’s twin planet, due to its solar system similarities to our planet. However, the differences are huge and originate mainly from the atmosphere and its effects. The atmosphere of Venus is mainly made of carbon dioxide, making the planet a giant greenhouse with a very high atmospheric pressure. Venus’s surface has a temperature of 850OF, and the rocky desert is full of craters, volcanoes, and former lava rivers.
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The Winds in Venus’s Atmosphere
Venus has a very thick atmosphere, mainly made up of carbon dioxide. This creates a pressure of 92 bars at Venus’s surface (92 times higher than the pressure at Earth’s sea level). Venus has atmospheric super-rotation: the winds at the top of the atmosphere travel at about 350 kilometers, which is about 60 times faster than Venus’s rotation speed. This speed is much faster than the category five hurricane on Earth. Even the fastest Earth winds move only 10−20% faster than Earth’s surface.
The winds are strong enough to blow away the free hydrogen in the atmosphere. Any water that gets into the atmosphere is quickly broken up into oxygen and hydrogen atoms by interactions with solar light, the hydrogen is blown off, and the oxygen pairs up with some other elements. Below these harsh winds, lie clouds of sulfuric acid.
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Is There Acid Rain on Venus’s Surface?
Venus’s surface is hot enough to melt lead. Hence, no liquid can survive on it, unless it is melted stones and metal. If the acid clouds rain, the liquid acid will evaporate as it gets close to the surface, due to the heat — consequently, no acid rains on Venus’s surface. Nevertheless, the surface is unpleasant enough, even without acid rain.
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Mountains and Volcanoes on Venus
To discover Venus’s surface, its mountains, lowlands, craters, volcanoes, and other topographic characteristics, Radio Detection and Ranging – RADAR – is used. Radar has shown that Venus is mainly covered in smooth volcanic plains. There are two highland regions, stretching over 20% of the surface.
In the northern hemisphere, there is Ishtar Terra, with an area of about the size of Australia or the continental United States. South of the equator is Aphrodite Terra, which is about the size of Africa. These ‘areas’ are almost similar to Earth’s continents, but they are not surrounded by oceans, nor were they at any time. Continents have mountains as well.
The highest Venus mountain is Maxwell Montes, a range near the north pole located on Ishtar Terra. Its peak is higher than Mount Everest: 11 kilometers above the average surface level. Maxwell Montes looks like the union of two mountains with its steep west and smooth east. The temperature on the peak is 15% lower than Venus’s surface, and the pressure is 45 bars. Still, lead would melt on the ‘cold’ mountain top.
There are 167 volcanoes on Venus with diameters over 100 kilometers across. Some of them are very similar to Earth volcanoes, like enormous Earth’s shield volcanoes, with an incline rising to a large hole, or caldera, at the top of the volcano. Maat Mons is Venus’s second tallest mountain and a volcano. It is eight kilometers high and 400 kilometers wide.
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Pancake, Arachnoid, and Coronae Volcanoes
Volcanoes on Venus can be ten to 100 times bigger than lava dome volcanoes on Earth. Some volcanoes on Venus are extremely round, wide, and have a flat and broad dome. Hence, they are called pancake volcanoes. The second type of Venus volcanoes is arachnoid volcanoes.
Arachnoid volcanoes are like spider webs, due to star-like fractures in both radial and concentric directions. They range in size from 40 to more than 200 kilometers in diameter. Arachnoid volcanoes might have been formed when magma upwelling below the crust formed fractures on the surface. Almost 100 of them have been found.
The third type is coronae volcanoes or crowns. As the name suggests, they are fractured circular features. Miranda, the moon most stretched and squeezed by the gravity of Uranus, also has coronae volcanoes.
In total, Venus’s surface is far from being Earth’s twin planet and is much too rough for Earth-like life to form.
Common questions about Venus’s Surface
Venus’s surface is a rocky desert with almost no dust. The atmosphere has led to a temperature of 850OF on the surface that can melt lead. Besides, the acid clouds and volcano eruptions make the surface gravely different from Earth’s and conditions for life. Images from space missions to Venus show that it is covered with craters, volcanoes, mountains, and big lava plains.
The average temperature on Venus’s surface is around 850 degrees Fahrenheit (462 degrees Celsius). The reason is the thick atmosphere dominated by 96% of carbon dioxide and the strong greenhouse effect it causes. Even though much of the Sun energy is reflected from Venus, its temperature is even higher than Mercury.
The Venera 4 mission by the Soviet Union in 1967 was the first to get through Venus’s thick atmosphere, but it could not land successfully. The first images of Venus’s surface came only when Venera 9 and 10 landed on Venus in 1975. Even after landing, spacecraft could not last long under the extreme heat and pressure of Venus’s surface. The longest time of data transmission from Venus is 127 minutes, and then the spacecraft was destroyed.
Maxwell Montes, a range near Venus’s north pole located on Ishtar Terra, has a peak higher than Mount Everest on Earth: about 11 kilometers above the average Venus’s surface level. The mountain is almost like two mountains in one, with a challenging, steep climb on the west side, while the east side would be a much more gradual walk up.
