The original post: /r/askscience by /u/Astronaut_Critical on 2025-02-13 14:22:31.

I’ve seen some news recently about changes in Earth’s core, and it got me thinking.

The Earth’s core is a solid-metal sphere, surrounded by liquid metal that’s constantly moving.

How does the solid sphere not melt and combine with the liquid metal? Is there a barrier?

If the core is hot enough to keep the metal liquid, why is there a solid mass?