As Venus appears to rise in the morning
and evening, it is often described as the morning and evening star. The Earth
and Venus have many similarities. They both have about the same densities, with
the Earth's being slightly higher at 5.52 g/cm³ and Venus at 5.26
g/cm³. Venus is also just slightly smaller than Earth. It is 95% of
Earth's diameter and 80% of Earth's mass. They also both have similar chemical
compositions and young surfaces as indicated by a small number of
craters.
However, there are also differences between Earth and Venus. Venus has a very thick atmosphere that is composed mostly of carbon dioxide. This dense atmosphere results in a greenhouse effect that results in temperatures of 740 K. Venus also has a very slow rotation period of 243 days. Venus does not have a magnetic field. This is probably because Venus is slightly smaller than Earth and also because Venus does not have a solid inner core.
Venus appears very bright, due to the albedo of its clouds and its thick atmosphere. Venus' clouds float in two broad layers, the lower of which is the densest. The cloud tops flow with the upper atmosphere. This movement of the atmosphere is what creates the view we see of Venus. Venus' atmosphere flows in a circular pattern created by rising warm air and sinking cold air. Cloud vortices cap the polar regions. The surface of Venus is basically flat other than three highland regions. The northern portion of Venus is mountainous with upland plateaus, while the southern area is flat with crated terrain.
moons: None
