Venus is the second closest planet to the Sun and has the highest surface temperature of any planet in our solar system, with an orbital period of about 225 Earth days. Because of its similar gravity and size, it is sometimes known as Earth’s “sister planet.” However, besides these two aspects, the two planets have almost nothing in common. With the densest atmosphere on any terrestrial planet in the solar system, the surface pressure on Venus is about 92 times that of Earth; the same pressure one kilometer beneath Earth’s oceans.
Even though Venus is comparatively much further away from the Sun than Mercury, it is the hotter planet with a surface temperature of around 462 °C; this is because of its dense atmosphere of greenhouse gases such as carbon dioxide and sulfur dioxide. One remarkable aspect of the atmosphere of Venus is the precipitation of liquid sulfuric acid. The surface geology of the planet has been observed by NASA for over twenty years now, and it is seen that there is extensive and violent volcanism at the surface.