Final answer:
The geology of Venus is similar to Earth's in scale and volcanic activity, but unlike Earth, Venus lacks plate tectonics. The planet's surface, mostly lowland lava plains, has been shaped by tectonics driven by mantle convection, forming distinct geological features. The inhospitable surface conditions are hostile to human life due to the extreme pressure, high temperature, and dense CO₂ atmosphere.
Step-by-step explanation:
Basic Geology of Venus
The geology of Venus is intriguing due to the resemblance in size and composition to Earth, yet they differ as Venus lacks plate tectonics. About 75% of Venus' surface is covered by lowland lava plains, similar to Earth's basaltic plains, yet formed differently without the crustal spreading associated with plate tectonics. Instead, Venus experienced what could be termed as "blob tectonics" where upwelling of hot material creates features like coronae and pancake volcanoes. The surface of Venus, showing less erosion and mostly aged at no more than 500 million years old, retains a clearer record of its geological history compared to Earth.
Surprise at Lack of Plate Tectonics
The lack of plate tectonics on Venus is surprising given its similarity to Earth in size and overall volcanic activity. Venus does show signs of tectonic activity driven by mantle convection, but this does not result in the mobile continental plates seen on Earth. Instead, the stress in Venus' crust forms ridges and cracks, with high regions such as Ishtar Terra emerging as a result of these forces.
Inhospitableness of Venus' Surface
Despite the geological similarities, the surface of Venus is inhospitable to human life, characterized by high pressure (90 bars) and temperature (730 K). This is further compounded by an atmosphere composed of 96% CO₂ and thick clouds of sulfuric acid that engender a substantial greenhouse effect. Russian Venera landers have successfully landed on Venus, but the environmental conditions make it hostile for human exploration.