Venus is similar to Earth in size and structure, and is our inner neighbor, the planet that gets closest to us and appears larger than any other in our sky. Yet it reveals little of itself—only a top layer of thick, unbroken blanket of cloud is visible.
structure and atmosphere
In diameter, Venus is only about 400 miles (650 km) smaller than Earth, and its internal layers are of similar size and composition. Below its silicate crust is a rocky mantle, and below this a core, which is solid in the center. It spins on its molten iron and nickel outer core solid iron and nickel inner core molten iron and nickel outer core solid iron and nickel inner core
axis more slowly than any other planet, one spin taking longer than one Venusian orbit. It also spins from east to west, the opposite direction of most other planets.
The 50-mile- (80-km-) deep atmosphere is predominantly carbon dioxide. A thick cloud deck of sulfuric acid droplets reflects away about 80 percent of the sunlight hitting Venus. The clouds also trap heat from the Sun. As a result, Venus is an overcast place with a surface temperature higher than that of any other planet.
THE PLANET'S iNTERiOR
Venus is a dense, rocky world whose material has settled to form layers. Its iron and nickel core has cooled and partly solidified. Molten subsurface mantle material is released onto the planet's surface as volcanic lava.
Volcanic features dominate the surface of Venus. About 85 percent of it is low-lying plain covered by volcanic lava. The remainder consists of three highland regions, the largest of which is Aphrodite Terra. The volcanic surface is relatively young in geological terms. Venus's hundreds of volcanoes and their extensive lava fields may be no more than 500 million years old. Some volcanoes may still be active.
Venus has unique flat-topped mounds of lava—pancake domes—and spiderlike volcanic features, known as arachnoids. Its surface is pitted with hundreds of impact craters. Along with other features on Venus, these are named after women.
Venus's volcanoes range widely in size. Maat Mons is a shallow-sloped shield volcano that grew with successive eruptions; it rises 5 miles (8 km) above the surface.
Was this article helpful?