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Venus, the first planet to ever be
observed by a passing spacecraft, Mariner 2 in 1962, and the hottest planet in the Solar
System, is known to be the Earth's sister planet or twin.
But unlike Earth, Venus has no signs of life, or oceans. None of our
Earth's plants or animals could ever survive on Venus, because of the high
temperature and the lack of oxygen. Venus, the second
planet from the Sun, is thought to be
the same size as the Earth and similar in composition and mass. The sixth
largest planet in our Solar System, Venus has a
diameter of 12,103,006 km, about 644 km smaller than that of the Earth.
Although Venus is called the Earth's twin, its
surface conditions appear to be very different from those of the Earth.
Venus' surface has mountains, canyons, valleys,
flat plains, and volcanoes, shaped by impact craters and tectonic activity.
Astronomers believe the ongoing volcanic activity to be the source of the
sulfur found in the atmosphere. Venus has an iron core or center with a radius of about 300 km. Venus does not have any
naturally occurring satellites or moons. No other planet comes closer to the Earth
than Venus.
Venus has large tornadoes which blow up to 384 km per hour. Venus is surrounded by a dense or thick atmosphere, and covered by clouds, which make it difficult for astronomers to learn about the surface of Venus. The temperature on Venus during the day rises to 484 degrees Celsius; the daytime temperature is so hot, it could melt lead. The thick atmosphere is made of sulfuric acid and carbon dioxide, with small amounts of nitrogen and water vapor.This dense blanket acts like a greenhouse and traps the heat. There is no water on Venus' surface because the hot surface temperature would make the water boil away. Venus, the brightest planet that can be viewed from the Earth, travels around the Sun in a nearly circular orbit once every 225 Earth days. Venus' rotation on its axis in a clockwise direction, opposite to the Earth's and the other planets' rotational direction, is very slow. A rotation takes 243 Earth days; a day on Venus is longer than a year on Venus. Venus is the only planet that does not rotate in the same direction in which it moves around the Sun.  Bibliography and Additional Sources of Information Solar System Exploration sse.jpl.nasa.gov/
Magellan Mission to Venus
www.jpl.nasa.gov/magellan/
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