Why does the inner core remain solid despite being extremely hot?

The inner core remains solid despite the extremely high temperatures primarily due to the immense pressure that exists at that depth within the Earth. Even though temperatures in the inner core can reach up to 5,700 degrees Celsius (about 10,300 degrees Fahrenheit), the pressure is so high—approximately 3 million times that at Earth's surface—that it forces the iron and nickel that make up the inner core into a solid state.

In contrast, the outer core, which is also composed of similar materials, is under significantly lower pressure, allowing it to remain in a liquid state. The balance between temperature and pressure is a key factor in determining the state of matter within the Earth's layers. This principle illustrates how pressure can lead to the solidification of materials even at temperatures that would normally cause them to be liquid. The unique conditions of temperature and pressure deep within the Earth are fundamental to understanding the behavior of the inner core.