Venus: Earth's Twin

Venus is the second planet from the sun and a close neighbor to the earth. It was named after the Roman Goddess of Beauty. Venus is usually one the brightest objects in the sky, which might be the reason it got its name. It is quite similar to the planet earth mainly in its size and a few other characteristics which is why it is often considered the Earth's twin. However, surface conditions are not nearly the same making it a quite inhospitable environment.

Here is some general information on Venus:

Diameter (miles)= 7,521

Mass (trillion trillion lbs)= 10.738

Density (earth=1)= .95

Gravity (earth=1)= .88

Period of Rotation (hours)= 5,832.2

Escape Velocity (mph)= 23,042

Major Atmospheric Gas= Carbon Dioxide

Inclination of Equator (degrees)= 2.6

Known Moons= 0

Mean Orbital Velocity (mph)= 78,364

Minimum Distance From Sun= 66.8 (millions of miles)

Maximum Distance From Sun= 67.7 (millions of miles)

Mean Distance From Sun= 67.2 (millions of miles)

Period of Revolution (earth years)= .63

Detailed information on Venus:

Venus' Phases--

Upon viewing Venus from a telescope, Venus can be seen going through "changes" in shape and size. Theses "changes" are actually called phases and are very similar to those that the moon goes through. This is a result on different parts of Venus' sunlit area being visible at different times. Venus can be seen on the opposite side of the sun about every 584 days as it and the earth make their orbits. Almost all the sunlit area can be seen at this point. As it continues its voyage around the sun, less of the sunlit area can be seen, but its size seems to increase. After about 221 days only half the planet is still visible. Then, 71 days later, only a thin sunlit area can be seen because Venus is now on the same side as the earth. As Venus moves away from the earth, it can be seen in the early evening sky. When it approaches the earth, it can be seen in the early morning sky.

Surface and Atmosphere--

While Venus may be known as "earth's twin" because of its size, it surface conditions are quite unsimilar from earth. It has been very difficult to learn about Venus because the planet is always surrounded by thick clouds of sulfur and sulfuric acid. This is probably due to active volcanoes on the planet. Like Mercury, the surface of Venus is extremely hot and dry. However, surface features like mountains, canyons, valleys and flat plains have been detected. Two of its mountain regions are the size of entire continents on earth. There is no water on Venus' surface because the high temperatures would simply make the water boil away. Of all the planets in the solar system, Venus has the heaviest atmosphere. The atmospheric pressure is estimated at 1,323 lbs. per sq.in as compared to earth's 14.7 lbs. per sq.in. It consists primarily of carbon dioxide but also has small amounts of of nitrogen and water vapor. There are minute traces of argon, carbon monoxide, neon and sulfur dioxide. Scientists believe that plants and animals that are found on earth could not exist on Venus because of the high temperature and insufficient oxygen. It is not known whether other forms of life exist there, but it is highly doubted.

Mass and Density--

Venus' mass is about four fifths that of earth and its force of gravity is also only slightly less than the earth's. For example: If an object weighed 100 pounds on earth it would weigh about 88 pounds of Venus. Venus's density is rather close to that of the earth as well, but is still slightly less. So, if you took a chuck of equal size out of the earth and Venus, Venus' piece would weigh a little less.

Space Flights to Venus--

On December 14, 1962, Venus became the first planet to be observed by a passing space craft. The U.S. Mariner 2 , an unmanned spacecraft, pass within 21, 600 miles of Venus after traveling through space for more than three and a half months. It conducted various measurements of conditions on and near the planet. In 1966, two unmanned Soviet spacecraft explored Venus, but one crashed into the planet. The next year, both an American and Soviet spacecraft reached Venus. Both reported large amounts of carbon dioxide in the planet's atmosphere. Mariner 10 flew by Venus on February 5 and reported that Venus had no magnetic field. Venera 9 , an unmanned Soviet craft landed on Venus and provided the first close-up photograph of the planet's surface. Three days later, the Venera 10 photographed Venus' surface and measured its atmospheric pressure. In December of 1978 four unmanned spacecraft reached Venus. The U.S. Pioneer Venus 1 began orbiting the planet and transmitted radar photographs. The second U.S. space craft, Pioneer Venus 2 studied Venus' density and chemical composition. The two Soviet crafts, Venera 12 and Venera 11 sent back data on the lower atmosphere of Venus. In May of 1989, the U.S. spacecraft Magellan was sent to Venus on a mission of mapping the planet with radar.