All About Venus:

Abstract

Venus is the second planet from the Sun and is the sixth largest planet. It is about 95% the diameter of Earth. Venus has no moons. A Venusian day is 243 Earth days long-longer than its year of 225 days! Venus can be seen in the night sky with the naked eye. It is often called the " evening star " or " morning star " depending on its place in the sky – but it is a planet, not a star! Venus is surrounded by a thick atmosphere – 92 times the atmospheric pressure at sea level on Earth-composed mainly of carbon dioxide. The surface temperature of Venus is about 482° C (900° F) – hotter even than Mercury! The carbon-dioxide-rich atmosphere traps heat from the Sun, and causes a " runaway greenhouse " effect responsible for Venus' high surface temperatures. Because Venus is so hot, there is no water at the surface or in the atmosphere. Interaction with the Sun has carried away the hydrogen component of water away from the planet. Clouds over Venus contain sulfuric acid droplets. Scientists think that Venus has active volcanos! There are more than 1000 volcanic regions on Venus. Some of Venus' volcanos have giant calderas (opening where the magma comes out) more than 100 kilometers (62 miles) in diameter. At least 85% of the surface of Venus is covered with volcanic rock. The surface of Venus has very few craters compared to Mercury or the Moon. This indicates its surface is relatively young; older surfaces like those on Mercury have many craters from billions of years of asteroid and comet impacts. Most of Venus's surface may be only 300 to 500 million years old; (yes, this is " young " to geologists; our Solar System is 4.6 billion years old!).