* Gravity: The immense gravity of a planet pulls all its mass towards the center. This pressure is strongest at the core.
* Compression: The immense pressure at the core compresses the materials, squeezing the atoms closer together. This increases density.
* Differentiation: During the early formation of a planet, heavier elements (like iron and nickel) tend to sink towards the center, while lighter elements (like silicates) rise towards the surface. This further contributes to the denser core.
Example:
* Earth's core is mostly made of iron and nickel, with a density of around 13 g/cm³.
* The Earth's mantle, which lies above the core, has a density of about 4.5 g/cm³.
* The Earth's crust, the outermost layer, has the lowest density, around 2.7 g/cm³.
This pattern of increasing density towards the center is common to most planets. While the specific composition and density can vary, the basic principle of gravitational compression and element differentiation remains the same.
