Saturn is a gas giant made almost entirely of hydrogen and helium. There is a dense metallic core at the center of the planet. It is surrounded by liquid metallic hydrogen and a layer of liquid hydrogen; the latter makes a gradual transition to a gas. Saturn's outermost layer of gas covers 1,000 km. Saturn's radius is about 9.5 times greater than that of our planet; Furthermore, the gas giant is more than 95 times more massive. To give a better idea of Saturn's size, we can say that around 764 E