Why is the inner core under more pressure than the outer core

It turns out that many materials can be a solid at a higher temperature if the pressure is also higher. So, even though it is hotter in the inner core, the pressure in the core is also higher, and you can have solid iron-nickel instead of liquid.

I hope this helps

My guess would be is that the inner core is under a lot more pressure than the outer core. think about it. would a ball be under more pressure if it is under water or floating?