Question

Why is the iron core of the earth solid? Explain you answer

Answer 1

That's as hot as the surface of the sun. The difference in temperature matters, because this explains how the Earth generates its magnetic field. The Earth has a solid inner core surrounded by a liquid outer core, which, in turn, has the solid, but flowing, mantle above it.

Answer 2

The difference in temperature matters, because this explains how the Earth generates its magnetic field. The Earth has a solid inner core surrounded by a liquid outer core, which, in turn, has the solid  flowing  mantle above it