As a geophysicist with a focus on the study of Earth's interior, I can explain the behavior of the Earth's inner core under pressure. The inner core of the Earth is primarily composed of iron and some nickel, similar to the composition of the outer core. However, the conditions within the inner core are vastly different. The pressure at the inner core is immense, estimated to be over 3.3 million times the atmospheric pressure at sea level on Earth's surface. This extreme pressure, combined with the high temperatures, results in a state of matter that is solid rather than liquid. The key to understanding why the inner core is solid despite the presence of a liquid outer core lies in the unique properties of the materials under such extreme conditions. Even though iron and nickel are generally liquids at the high temperatures found in the outer core, the pressure in the inner core is so great that it forces these metals into a solid state. This is an example of a phase of matter where the pressure is the dominant factor over temperature, a phenomenon that can be observed in the behavior of some materials under very high pressures. read more >>

2 metals found in the outer core are iron and nickel.The boarder between the Outer Core and the Inner Core is 5100 kilometers. The Inner Core is under so much pressure it does not move like a liquid, it moves like a solid because it has so much pressure.read more >>