Venus

Venus is the second planet from the Sun. It is a rocky planet with the densest atmosphere of all the rocky bodies in the Solar System, and the only one with a mass and size that is close to that of its orbital neighbour Earth. Orbiting inferiorly (inside of Earth's orbit), it appears in Earth's sky always close to the Sun, as either a "morning star" or an "evening star". While this is also true for Mercury, Venus appears much more prominently, since it is the third brightest object in Earth's sky after the Moon and the Sun, appearing brighter than any other star-like classical planet or any fixed star. With such a prominence in Earth's sky, Venus has historically been a common and important object for humans, in both their cultures and astronomy. Venus has a weak induced magnetosphere and an especially thick carbon dioxide atmosphere, which creates, together with its global sulfuric acid cloud cover, an extreme greenhouse effect. This results at the surface in a mean temperature of and a crushing pressure of 92 times that of Earth's at sea level, turning the air into a supercritical fluid, while at cloudy altitudes of above the surface, the pressure, temperature and also radiation are very much like at Earth's surface. Conditions possibly favourable for life on Venus have been identified at its cloud layers, with recent research having found indicative, but not convincing, evidence of life on the planet. Venus may have had liquid surface water early in its history, possibly enough to form oceans, but runaway greenhouse effects eventually evaporated any water, which then was taken into space by the solar wind. Internally, Venus is thought to consist of a core, mantle, and crust, the latter releasing internal heat through its active volcanism, shaping the surface with large resurfacing instead of plate tectonics. Venus is one of two planets in the Solar System which have no moons. Venus has a rotation which has been slowed and turned against its orbital direction (retrograde) by the strong currents and drag of its atmosphere.