There is pressure within the earth due to the overlying material that the earth is formed from. The deeper within the earth you go, the greater the amount of overlying material pushing down due to gravity and so the greater the pressure. As the inner core has the largest amount of overlying material pushing down upon it, it experiences the greatest pressure.
The layers of the Earth in order from lowest pressure to greatest pressure are the crust, mantle, outer core, and inner core. The inner core experiences the highest pressure due to the weight of all the layers above it.
The Earth's inner core has the greatest temperature, reaching up to around 5700 degrees Celsius. The layer with the greatest pressure is the inner core as well, with pressures exceeding 330 to 360 gigapascals.
At the very center.
The amount of pressure overcomes the material's disposition to melting at high temperature. It solidifies.
The Inner Core is the source of the internal heat of the Earth. This is composed of heat generated by gravitational pressure, and by the heat from nuclear disintegration of radioactive materials. This heat gradually spreads outwards.
The reason that the inner core is a solid and the outter core is a liquid is because the inner core is the greatest amount of pressure from the other layers. Why the outter core is a liquid is because inside of it is metal that just flows around in there.
The inner core has the most or highest amount of density (iron/nickel).
The lowest level, the troposphere near the Earth's surface, has the highest pressure.
Iron, though it does have a small amount of nickel.
It is the innermost layer of the Earth. Also under the greatest pressure and the hottest. It is considered a solid and is composed primarily of iron. it is also the CENTER OF THE EARTH
Earth
At the center of the inner core the pressure is roughly 3,600,000 atmospheres. According to Wikipedia.