Venus is the second planet from the Sun. It has the densest atmosphere of all rocky bodies in the Solar System, so dense that at surface level and 92 atmospheres, it is a supercritical fluid. The planet's surface is dominated by volcanoes – there are 167 Venusian volcanoes that are over 100 km (60 mi) across. Venus has a diameter roughly equal to Earth's at 12,104 km (7,521 mi) and is classified as a terrestrial planet. The surface of Venus has unique features of volcanic origin, such as 'farras' which are wide pancake-like lava domes and 'arachnoids' which are concentric fractures resembling spider webs. It is thought that the planet's crust is releasing internal heat through active volcanism and shaping the surface with large resurfacing. Above, Venus's atmosphere has a rough composition of 96.5% carbon dioxide, 3.5% nitrogen, and reflective sulfuric acid cloud cover. Venus has a weak induced magnetosphere. Venus has a solar year that is 224.7 Earth days long and a solar day that is 117 Earth days long. Its dense atmosphere is the reason why the planet has a slow retrograde rotation and an extreme greenhouse effect. This is demostrated by Venus's average and consistent surface temperature of 464 °C (867 °F). Geological processes on Venus are relatively slow as shown by lack of erosion in craters, though there are some evidence that the planet still has active volcanism. Venus has no natural satellite. Like other planets in the Solar System, Venus was formed approximately 4.5 billion years ago. As of the early 2020s, it is suggested that Venus's atmosphere might be similar to one surrounding the early Earth and there may have been substantial quantities of surface liquid water. Back then, Venus might be more conducive to life. Over billions of years, solar forcing and large volcanic resurfacing may have eroded the initial atmosphere and created the new carbon dioxide-rich atmosphere. Venus is the third brightest object in Earth's sky after the Moon and the Sun, therefore it has been important in human culture. Venus was the second planet to be visited by humans, with the first flyby by the Mariner 2 probe in 1962, the first atmospheric entry by the Venera 4 probe in 1967, the first successful landing by the Venera 8 probe in 1972 and the first orbiting probe by Venera 9 in 1975. As of 2024, there is no active probe on Venus, though it is a subject of three missions as a gravity assist waypoint. Source: Wikipedia (en)