The fifth planet from the Sun and the largest planet in our solar system. Jupiter orbits the Sun at an average distance of 5.2 time Earth's distance (about 465 million miles/745 million km). The planet has a mass 318 times the mass of Earth and a radius 11.2 times the radius of Earth. Jupiter is a gas planet and has no solid surface. It is made of hydrogen and helium, with trace amounts of ammonia, water vapor, and methane. The most recognizable features of the planet are its bands of clouds and a giant storm visible from Earth called the Great Red Spot. Jupiter has more than 60 known moons, the largest of which are Io, Europa, Ganymede, and Callisto.