False-color global radar view of Venus (without the clouds) from Magellan between 1990 and 1994
Venus is the second planet from the Sun. As the second-brightest natural object in the night sky after the Moon, Venus can cast shadows and, rarely, is visible to the naked eye in broad daylight. Venus lies within Earth's orbit, and so never appears to venture far from the Sun, setting in the west just after dusk and rising in the east a bit before dawn. Venus orbits the Sun every 224.7 Earth days.
With a rotation period of 243 Earth days, it takes longer to rotate about its axis than any planet in the Solar System and rotates in the opposite direction to all but Uranus (meaning the Sun rises in the west and sets in the east). Venus does not have any natural satellites, a distinction it shares only with Mercury among planets in the Solar System.
The inner structure of Venus – the crust (thin outer brown layer), the mantle (red middle layer) and the core (yellow inner layer),by Nasa
Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, mass, proximity to the Sun, and bulk composition. It is radically different from Earth in other respects. It has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide. The atmospheric pressure at the planet's surface is 92 times that of Earth, or roughly the pressure found 900 m (3,000 ft) underwater on Earth. Venus is by far the hottest planet in the Solar System, with a mean surface temperature of 735 K (462 °C; 863 °F), even though Mercury is closer to the Sun. Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. It may have had water oceans in the past, but these would have vaporized as the temperature rose due to a runaway greenhouse effect. The water has probably photodissociated, and the free hydrogen has been swept into interplanetary space by the solar wind because of the lack of a planetary magnetic field. Venus's surface is a dry desertscape interspersed with slab-like rocks and is periodically resurfaced by volcanism.
As one of the brightest objects in the sky, Venus has been a major fixture in human culture for as long as records have existed. It has been made sacred to gods of many cultures, and has been a prime inspiration for writers and poets as the morning star and evening star. Venus was the first planet to have its motions plotted across the sky, as early as the second millennium BC.
Using an ultraviolet filter of imaging system, the photo has been color-enhanced to simulate Venus's natural color as the human eye would see it. Venus is perpetually blanketed by a thick veil of clouds high in carbon dioxide and its surface temperature approaches 900 degrees fahrenheit. Launched on 11/3/73 atop an Atlas-Centaur rocket, Mariner 10 flew by Venus on 2/5/74.
As the planet with the closest approach to Earth, Venus has been a prime target for early interplanetary exploration. It was the first planet beyond Earth visited by a spacecraft (Mariner 2 in 1962), and the first to be successfully landed on (by Venera 7 in 1970). Venus's thick clouds render observation of its surface impossible in visible light, and the first detailed maps did not emerge until the arrival of the Magellan orbiter in 1991. Plans have been proposed for rovers or more complex missions, but they are hindered by Venus's hostile surface conditions.
Phases de Vénus et évolution de son diamètre apparent. Lieu : fr:Thessalonique, fr:Grèce Dates : Du 27/02 au 08/06/2004 Auteur : Statis Kalyvas Source : fr:Observatoire européen austral (European Southern Observatory - ESO) site Termes de l'autorisation de l'ESO : « All photos on this page may be downloaded and used, provided the photographers (authors) and the VT-2004 programme are indicated as source. » fr:Catégorie:Image d'astronomie
In January 2020, astronomers reported evidence that suggests that Venus is currently volcanically active.
It is named after the Roman goddess of love and beauty.