Saturn's interior is similar to Jupiter's interior. It has a small rocky core about the size of the Earth at its center. It is very hot; its temperature reaches 15,000 K (). Saturn is so hot that it gives out more heat energy into space than it receives from the Sun. Above it is a thicker layer of metallic hydrogen, about deep. Above that layer is a region of liquid hydrogen and helium. The core is heavy, with about 9 to 22 times more mass than the Earth's core.