According to National Geographic, the inner core of the Earth ranges between 9,000 and 13,000 degrees Fahrenheit. This is approximately as high as the temperature of the sun's surface.
The Earth's inner core is composed mostly of iron accompanied by trace elements. Due to the incredible pressure around the inner core, the ball of iron remains solid despite the temperatures. Surrounding the inner core is the outer core, which contains liquid iron ranging from 7,200 to 9,000 degrees Fahrenheit. It is responsible for the planet's magnetic field. Above the outer core rests the mantle, which is solid rock. The solid rock, however, is slow moving and still extremely hot. The Earth's crust is the top-most layer.