Under what circumstances can differentiation occur in a planet? The planet must be made of both metal and rock. The planet must have an atmosphere. The planet must have a molten interior. The planet must have a rocky surface. The planet must be geologically active, that is, ?have volcanoes, planetquakes, and erosion from weather.
The correct answer and explanation is :
Correct Answer: The planet must have a molten interior.
Explanation (300 words):
Differentiation in a planet refers to the process by which denser materials, such as metals, sink toward the planet’s center, while lighter materials, like silicates and rocks, rise toward the surface. This leads to the formation of distinct layers within the planet—typically a metallic core, a rocky mantle, and a crust.
For differentiation to occur, the planet must have a molten interior, at least during part of its early history. When a planet is molten, materials within it can move and flow according to their densities. Heavier elements like iron and nickel naturally sink toward the center, while lighter, less dense materials float upward. This movement is only possible in a liquid or partially molten state. In a solid, unmelted planet, materials are locked in place and cannot rearrange themselves according to density.
The presence of both metal and rock is necessary for differentiation to create layered structures, but this alone is not sufficient. Without melting, the materials remain mixed. An atmosphere, volcanic activity, or a rocky surface are consequences or results of differentiation and internal heating, not prerequisites for the process to begin.
Planetary heating that leads to a molten interior can result from several factors, including:
- Accretional heating from impacts during planet formation,
- Gravitational compression,
- Radioactive decay of isotopes,
- Tidal heating in some cases.
Once a planet becomes large enough and hot enough to partially or fully melt, differentiation can occur rapidly in geological terms. This process is critical in planetary evolution and is responsible for the development of magnetic fields (through movement in the metallic core), volcanism, and tectonic activity.
In summary, a molten interior is the essential condition for differentiation to take place in a planet, enabling the separation and organization of its internal materials into distinct layers.