Venus: Foundations

The planet has a rocky differentiated interior, a crust shaped by volcanism and tectonic deformation, a massive CO2-rich atmosphere, and thick cloud decks high above the surface. Venus rotates very slowly in a retrograde direction, and its atmosphere super-rotates much faster than the solid planet.

A powerful greenhouse effect traps outgoing infrared radiation and keeps the lower atmosphere extremely hot. With little surface water and no Earth-like plate tectonics, Venus loses one major pathway for cycling carbon into rocks. Mantle convection and volcanism continue to reshape the crust, while the dense atmosphere transports heat efficiently around the planet.

Radar mapping from spacecraft such as Magellan penetrated the cloud cover and revealed lava plains, volcanoes, coronae, ridges, and impact craters. Soviet Venera landers measured surface conditions directly, while spectroscopy established the atmospheric composition and cloud chemistry. Crater statistics suggest much of the surface is geologically young compared with the age of the planet.

Venus is near Earth in size and mass but radically different at the surface: a dense carbon-dioxide atmosphere, global clouds, surface pressure around 90 times Earth's, and temperatures hot enough to melt lead. Its climate demonstrates that similar planetary size does not guarantee similar habitability.