Venus is a terrestrial (rocky) planet, similar in size and mass to Earth, often described as Earth's "sister" or "twin" planet. It is the second planet from the Sun and has a solid surface composed mainly of silicate rock and metals, with a metallic iron core and a rocky mantle and crust similar to Earth's structure

. However, Venus differs drastically from Earth in its atmospheric and surface conditions. Its atmosphere is extremely dense and thick, composed mostly of carbon dioxide (about 96.5%) with nitrogen making up most of the rest, and it has a global layer of sulfuric acid clouds. This dense atmosphere causes a strong greenhouse effect, resulting in surface temperatures around 464 °C (867 °F), hot enough to melt lead. The surface pressure is about 92-95 times that of Earth's at sea level, making the atmosphere supercritical near the surface

. Venus rotates very slowly in a retrograde direction, with a day longer than its year, and it has no moons. Its surface features include volcanic plains, mountains (such as the large volcano Maat Mons), and evidence of past volcanism, but it lacks Earth-like plate tectonics

. In summary, Venus is a rocky terrestrial planet with a thick, carbon dioxide-rich atmosphere, extreme surface temperatures, and high pressure, making it the hottest planet in the Solar System