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• Space probes to Venus

Venus, the second planet from the Sun, is the closest planet to Earth. It is visible in the sky either three hours after sunset or three hours before sunrise, depending on the season. This pattern prompted early astronomers to refer to the planet as the "evening star" or the "morning star." Venus is named for the Roman goddess of love and beauty. Throughout history, the planet has been thought of as one of the most beautiful objects in the sky.

Venus and Earth have long been considered sister planets. The reason for this comparison is that they are similar in size, mass, and age. The diameter of Venus at its equator is about 7,500 miles (12,000 kilometers). The planet revolves around the Sun at an average distance of 67 million miles (107 million kilometers). It takes Venus about 225 Earth days to complete one revolution. The planet spins extremely slowly...