Venus is the second nearest planet from the sun. It is only a little smaller than the earth, about 95% of the earth's diameter(直径) and 80% of the earth's mass (质量). Earth and Venus are sometimes called the twin planets.
The word Venus means the goddess of love and beauty in Greek. ____________ probably because it is one of the brightest planets we have known by now. We human beings have known Venus for a long time. It has a cloudy atmosphere. This helps it reflect sunlight. So it appears to be very bright. It is easily observed in the sky. It is seen near the sun. It seems that it is the brightest thing in the sky except the sun and the moon. Venus reaches its maximum (最大的) brightness shortly before sunrise or shortly after sunset, and is often thought as the Morning Star or as the Evening Star. A lot of observation of Venus was important to Copernicus's Heliocentric Theory (日心说) of the solar system.
Scientists for years thought that Venus was very likely to have life in some forms. In 1962, scientists sent the first spacecraft to explore Venus, and we will know more about Venus in the future.
