The second largest planet is Saturn. Its distance from the Sun is approximately 1.4 billion kilometers. Saturn takes 29.5 years to make a complete journey around the Sun. The flybys in the early 1980s taught us much about this planet. Saturn has seven major rings. Some are made of thinner rings known as ringlets. The rings are 2 kilometers thick and are made of particles that range in size from several centimeters to a few meters. Saturn is less dense than water. It has winds that move at 500 meters per second. Saturn’s atmosphere is composed of hydrogen, with small quantities of methane and helium.