Fill in the Blanks planetsOnline version learn the planets by Alexa Lorena Ramirez 1 Jupiter Uranus Mars Mercury Saturn Neptune Earth is the closest planet to the Sun , is easily the largest and most massive planet in the Solar System , is the third planet from the Sun and largest of the terrestrial planets . , is the fourth planet from the Sun and last of the terrestrial planets , is the sixth planet from the Sun and second largest planet of the Solar System in terms of diameter and mass , is the seventh planet in the Solar System and third of the gas giants , is the eighth planet from the Sun and last of the known planets .