Why is the earth's core molten and not consuming everything around it?

Many misconceptions are apparent in the question itself. First, it is commonly believed that the Earth's inner core is made of solid nickel and iron, despite its high temperature and intense pressure from gravity. In contrast, the outer core has lower pressure, which allows it to be liquid.

Regarding the idea that it would consume everything nearby, you should be aware of the principle known as the Law of Conservation of Mass, which holds that matter cannot be created or destroyed. This means that, in the event that a rock was dropped into lava, it would not be consumed but rather melt and become a part of the lava.

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Because of the high temperatures and pressures found deep within the planet, the Earth's core is molten, but it doesn't consume everything around it because the solid mantle and crust, as well as the Earth's outer layers, act as insulators, keeping the intense heat from the core from reaching the surface. The molten iron and nickel in the outer core also moves, creating an Earth's magnetic field that helps shield the surface from the intense heat of the core.