Planets & Solar System
Venus inside and out We don’t know much of Venus’s interior, and what we know of its atmosphere isn’t pretty While our knowledge of Venus’s internal makeup is mostly based on speculation, we do know that it does not include a dynamo, like Earth’s. A dynamo is a convecting, rotating fluid that conducts electricity and is responsible for a planet’s magnetic field. Venus may have a liquid outer core and that conducts electricity, but does not convect and rotates too slowly to produce a dynamo. The Earth has a dynamo in part because its liquid core is hotter on the bottom than on the top, creating convection. Venus’s core may be all one temperature. But why? Some believe Venus was subject to an unknown event on its surface, which caused an end to plate tectonics on the surface and led to a cooling of the core. Venus’s core could be completely solid or liquid. What we do know is its magnetic field, which is very weak, is caused by interactions between the ionosphere (ionised upper atmosphere) and solar wind. Venus has the densest atmosphere in the Solar System, with a mass about 90 times that of Earth’s atmosphere. There’s a heavy, sulphuric layer of clouds that scatter about 90 per cent of the sunlight, which prevents viewing of the planet’s surface and keeps it dim. Below the cloud layer is a layer of carbon dioxide, mixed with a bit of nitrogen. Pressure on the surface is 92 times that of Earth’s surface. Although Venus is far away from the Sun, its atmosphere creates a greenhouse effect that results in an incredibly hot temperature of 460°C (860°F). The temperature stays the same most of the time, with winds of up to 300 km/h (186 mph). Some scientists believe Venus once had an atmosphere like Earth’s, and even had oceans, but the greenhouse effect eventually evaporated all of the water.
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The structure of Venus Crust Venus’s crust is mainly made up of silicate rocks
Mantle The mantle is likely rocky and similar in composition to Earth's
Core The core is probably molten metal, but how much of it is liquid and how much is solid remains a mystery
