Why is the inner core of the earth solid even though its so hot?

Answer 1

The melting point of materials varies depending on the applied pressure. As pressure increases so does the melting temperature. This relationship is normally shown in a phase diagram.

The main constituent of the inner core is iron and the inner core pressure is approximately 330-360 GPA while the temperature varies from approximately 5000 to 7000 K.

The extremely high pressures in the Earth's inner core therefore drive the melting point of the iron up beyond the temperature that occurs and the metals of the inner core cannot melt.

As such the inner core is solid, even though it is the highest temperature region in the Earth.

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Answer 2

The inner core is under enormous pressure. Temperature and pressure are both parameters which affect the phase of matter.

Answer 3

The high pressure at the center of the earth keeps the inner core solid despite its high temperature. The intense pressure prevents the core from melting, maintaining its solidity.