Venus (Courtesy to Microsoft Encarta for this photograph.)

Venus is the next brightest object in the sky after the Sun and the Moon. It appears just before sunrise and sunset. This is the reason why Venus is known as the "Morning Star" and the "Evening Star." It is never visible for more than three hours after sunrise and sunset.

People used to think that Venus was the sister of our planet. Scientists didn't think very much about it because they did not know very much about Venus. They were very surprised by the findings later on. When Mariner 10 flew past Venus on its way to Mercury, it took some pictures. The pictures didn't prove very much though. Later space probes really studied Venus well. What they found was the complete opposite of the previous thoughts about Venus. The probes found a rocky, barren land with a very thick atmosphere. The atmosphere was very acidic which was made mainly of carbon dioxide and sulfuric acid. It does rain on Venus, but the precipitation never reaches the ground.

The winds on Venus vary tremendously. In the upper atmosphere, the winds can blow as high as 225 miles per hour, and the winds that are near the surface of the planet blow at a much lower 2 to 11 miles per hour. Although the winds are light on the surface, they have the force of a river because of so much air. On Venus air pressure is tremendous. It is 90 times that of the air at sea level on Earth. So much air makes light travel through like it does through water on Earth. That is why it is very hard to see through Venus' clouds and air. We have mapped out at least 93 percent of Venus' surface thanks to the combined effort of Russia's space probes, the United States' space probes, and powerful radio telescopes on Earth.