Venus is the seicont planet frae the Sun, orbitin it every 224.7 Yird days. The planet is named efter the Romangoddess o love an beauty. Efter the Muin, it is the brichtest naitural object in the nicht sky, reachin an apparent magnitude o −4.6, bricht enough tae cast shadows. Acause Venus is an inferior planet frae Yird, it never appears tae venture far frae the Sun: its elongation reaches a maximum o 47.8°. Venus reaches its maximum brichtness shairtly afore sunrise or shortly efter sunset, for which reason it haes been referred tad bi auncient culturs as the Mornin Star or Evenin Star.
Venus is a terrestrial planet an is sometimes cried Yird's "sister planet" acause o their similar size, gravity, an bulk composeetion (Venus is baith the closest planet tae Yird an the planet closest in size tae Yird). However, it haes an aa been shawn tae be very different frae Yird in ither respects. It haes the densest atmosphere o the fower terrestrial planets, consistin o mair than 96% carbon dioxide. The atmospheric pressure at the planet's surface is 92 times that o Yird's. Wi a mean surface temperatur o 735 K(462 °C; 863 °F), Venus is bi far the hottest planet in the Solar Seestem. It haes na carbon cycle tae lock carbon back intae rocks an surface features, nor daes it seem tae hae ony organic life tae absorb it in biomass. Venus is shrouded bi an opaque layer o heichly reflective cloods o sulfuric acid, preventin its surface frae being seen frae space in veesible licht. Venus mey hae possessed oceans in the past, but these would hae vaporized as the temperatur rose due tae a runaway greenhoose effect. The watter haes maist probably photodissociated, an, acause o the lack o a planetary magnetic field, the free hydrogen haes been swept intae interplanetary space bi the solar wind. Venus's surface is a dry desertscape interspersed wi slab-like rocks an periodically refreshed bi volcanism.
↑Hashimoto, G. L.; Roos-Serote, M.; Sugita, S.; Gilmore, M. S.; Kamp, L. W.; Carlson, R. W.; Baines, K. H. (2008). "Felsic highland crust on Venus suggested by Galileo Near-Infrared Mapping Spectrometer data". Journal of Geophysical Research, Planets113: E00B24. Bibcode:2008JGRE..11300B24H. doi:10.1029/2008JE003134.
↑B.M. Jakosky, "Atmospheres of the Terrestrial Planets", in Beatty, Petersen and Chaikin (eds,), The New Solar System, 4th edition 1999, Sky Publishing Company (Boston) and Cambridge University Press (Cambridge), pp. 175–200