The Earth's interior is composed of four layers, three solid and one liquid?not magma but molten metal, nearly as hot as the surface of the sun.
The deepest layer is a solid iron ball, about 1,500 miles (2,400 kilometers) in diameter.
The iron isn't pure?scientists believe it contains sulfur and nickel, plus smaller amounts of other elements.
Estimates of its temperature vary, but it is probably somewhere between 9,000 and 13,000 degrees Fahrenheit (5,000 and 7,000 degrees Celsius).
Above the inner core is the outer core, a shell of liquid iron.
This layer is cooler but still very hot, perhaps 7,200 to 9,000 degrees Fahrenheit (4,000 to 5,000 degrees Celsius).
It too is composed mostly of iron, plus substantial amounts of sulfur and nickel.
It creates the Earth's magnetic field and is about 1,400 miles (2,300 kilometers) thick.