Astronomers refer to Venus as Earth's sister planet. Both are similar in size mass, density and volume. "In 1962 Mariner 2 became the first spacecraft to visit Venus" (Venus 1). Now this planet has been visited by more than 20 other spacecrafts; most recently the U.S. spacecraft Magellan that produced detail maps of Venus" surface using radar. Venus is scorched with a surface temperature of about 235K during the day and 240K at night (Kopal 47). This makes Venus even hotter than Mercury. This high temperature is primarily due to a run away green house effect caused by the heavy atmosphere of carbon dioxide. Date from Magellan's imaging radar shows that Venus probably once had large amount of water like Earth but it all boiled away this make it quite a dry planet now (Venus 2). Recent findings indicate Venus is still volcanically active but only in a few hot spots. There are no known satellites or moons on Venus. It is the brightest object in the sky except for the Sun and the Moon, which makes it visible with the naked eye.
Earth is the third planet from the sun, the firth largest and densest major body in the solar system. Unlike all of the other planets names that come from Greek/Roman mythology Earth is old English (Earth 1). The earth takes one year (365 days) to complete one rotation. The Earth is divided into several layers including the crust, upper mantle, transition region, lower mantel, outer core and inner core. Amazing enough, temperatures at the center of the core reach as high as 7500 degrees Kelvin, which is hotter than the surface of the sun (Earth 1)! Earth's crust is divided into several separate solid plates, which float around independently on top of the hot mantle (Earth 2). The eight major plates on the Earth are the North American Plate, South American Plate, Antarctic Plate, Eurasian Plate, African Plate, Indian Plate Nazca Plate, and the Pacific Plate.
