# How is it that earth's inner core is still solid?

Earth's inner core is made up of an alloy of Iron and Nickel.

The important note here is that it is solid.

The temperature at the inner core is about $$5,763K = 5,490\text{ degrees C}$$.

Now the melting point of both solid iron and nickel is about $$1,500\text{ degrees C}$$, and even though they are combined, I still think that $$5,490$$ is much greater then the melting point of the alloy.

Regardless, how is it that the inner core still stays solid? I would expect that at such higher temperatures, a phase change to liquid, or maybe even gas would occur.

Why does it not?

• Because pressure. Nov 23, 2018 at 4:47
• There's a typo, a digit missing in "5,77 K". Nov 23, 2018 at 17:40
• Wikipedia's article on the inner core links to Science 2013, 340, 464-466, which states that "[...] we conclude that the melting temperature of iron at the inner core boundary is 6230 ± 500 kelvin." Nov 24, 2018 at 0:08