Here's the breakdown:
* Outer Core: Made up of liquid iron and nickel. The immense pressure from the Earth's mantle keeps the outer core in a liquid state, despite the extreme temperatures.
* Inner Core: Made up of solid iron and nickel. While the inner core is even hotter than the outer core, the intense pressure from the entire planet above it is so great that it forces the atoms of iron and nickel to pack tightly together. This intense pressure overcomes the heat, preventing the inner core from melting.
So, while the inner core is extremely hot, it is solid due to the immense pressure. It's like squeezing a sponge: even if it's hot, the pressure keeps it from expanding into liquid.
