Jupiter is the largest planet in the solar system and is located in the outer solar system. It is made primarily of liquid hydrogen and has over 60 moons. Jupiter orbits the sun every 12 years and has an average temperature of -153°C. Mercury is the smallest planet and closest to the sun. It is located in the inner solar system and is made mostly of metal. Mercury orbits the sun every 88 days and has an extremely high average temperature of 465°C due to its proximity to the sun. The two planets differ greatly in size, composition, location and temperature.