The inner core is solid only because of the very high pressure of the outer core and mantle . Say, if the inner core moved a teeny tiny bit would some of it liquify and melt? Or does it stay solid? Also if the Inner core bulged would a bump about 1/8 of the size of the mantle occur on the inner core because of space taken up?
The following paragraphs are reproduced from https://www.nationalgeographic.org/encyclopedia/core/
"Growth in the Inner Core
As the entire Earth slowly cools, the inner core grows by about a millimeter every year. The inner core grows as bits of the liquid outer core solidify or crystallize. Another word for this is “freezing,” although it’s important to remember that iron’s freezing point more than 1,000° Celsius (1,832° Fahrenheit).
The growth of the inner core is not uniform. It occurs in lumps and bunches, and is influenced by activity in the mantle.
Growth is more concentrated around subduction zones—regions where tectonic plates are slipping from the lithosphere into the mantle, thousands of kilometers above the core. Subducted plates draw heat from the core and cool the surrounding area, causing increased instances of solidification.
Growth is less concentrated around “superplumes” or LLSVPs. These ballooning masses of superheated mantle rock likely influence “hot spot” volcanism in the lithosphere, and contribute to a more liquid outer core.
The core will never “freeze over.” The crystallization process is very slow, and the constant radioactive decay of Earth’s interior slows it even further. Scientists estimate it would take about 91 billion years for the core to completely solidify—but the sun will burn out in a fraction of that time (about 5 billion years)."