Jupiter's moon Ganymede is the largest moon in the solar system, and it is also the third-largest moon in the solar system after the Earth's moon and Saturn's moon Titan. Venus is the second planet from the Sun, and is the closest planet to Earth. It is the brightest object in the night sky and is also sometimes called the Morning Star or the Evening Star. Venus is famous for its thick atmosphere, which is composed mainly of carbon dioxide and nitrogen. It has an active volcanic surface and its day lasts longer than a year.