The Solar System The solar system is a family of objects, which orbit the sun. They were born 4.6 billion years ago. The most important are the 9 planets, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Mercury is the closest to the sun and Pluto is the farthest. The solar system also includes the stars and the moon. The Heliocentric model was created in 1543 and it shows how the solar system functions. In the model the stars and the sun are stationary they don’t move. The planets including earth move in circles around the sun in an eastward motion. It takes a year for the earth to make a complete circle around the sun. Th