VENUS

Venus is the second planet from the Sun. It is named after the Roman goddess of love and beauty. As the second-brightest natural object in the night sky after the Moon, Venus can cast shadows and can be, on rare occasion, visible to the naked eye in broad daylight. Venus lies within Earth's orbit, and so never appears to venture far from the Sun, either setting in the west just after dusk or 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 other planet in the Solar System and does so 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 moons, a distinction it shares only with Mercury among planets in the Solar System.
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 about 92 times the sea level pressure of Earth, or roughly the pressure at 900 m (3,000 ft) underwater on Earth. Venus has by far the hottest surface of any planet in the Solar System, with a mean temperature of 737 K (464 °C; 867 °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' 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.

Interesting Facts:

• A day on Venus is longer than a year:
  It takes Venus longer to rotate once on its axis than to complete one orbit of the Sun. That’s 243 Earth days to rotate once - the longest rotation of any planet in the Solar System - and only 224.7 Earth days to complete one orbit of the Sun.
  
• Venus is hotter than Mercury despite being further away from the Sun:
  Its mean temperature is 462°C. This is because of the high concentration of carbon dioxide in Venus’ atmosphere which works to produce an intense greenhouse effect, trapping heat in the atmosphere like a blanket and causing the temperature of the planet to be much higher than its proximity to the Sun would suggest.
  
• Unlike the other planets in our solar system, Venus spins clockwise on its axis:
  All other planets spin anti-clockwise on their axis and orbit the Sun in an anti-clockwise direction. Venus also orbits the Sun anti-clockwise, but its unusual axis rotation is due to being upside down - it was knocked off its upright position earlier in its history! Astronomers believe that at some point, a colliding celestial body tilted Venus so far off its original position that it is now upside down. The only other planet to spin in a weird direction is Uranus which spins on its side, probably the result of another collision early on in its life.
  
• Venus is the second brightest natural object in the night sky after the Moon:
  The clouds of sulfuric acid in Venus’ atmosphere make it reflective and shiny and obscure our view of its surface. It's brightness makes it visible during the day if it’s clear and you know where to look Image of Heavenly Neighbours © Saber Karimi, shortlisted for Insight Astronomy Photographer of the Year 2017 Heavenly Neighbours © Saber Karimi, shortlisted for Insight Astronomy Photographer of the Year 2017
  
• Venus has 90 times the atmospheric pressure of Earth:
  That’s about the same as the pressure at a depth of 1 km in Earth's oceans.
  
• Venus is named after the Roman goddess of love and beauty:
  It is thought that Venus was named after the beautiful Roman goddess (counterpart to the Greek Aphrodite) due to its bright, shining appearance in the sky. Of the five planets known to ancient astronomers, it would have been the brightest.