Why is it that terrestrial planets are thought to have dense iron cores?
A) Thermonuclear reactions produced iron as a fusion product in the earlier phases of planetary evolution (thermonuclear accretion).
B) During the formation of the planets, heavy elements accumulated first, followed by the accretion of lighter elements onto them (bimodal accretion).
C) The planets were molten early in their lives, and the heavy elements sank and lighter materials floated to the surface (planetary differentiation).
D) Magnetism in the iron was sufficiently powerful to pull iron atoms to the center as the planet formed (magnetic sorting).

Question

Quizplus · Accepted Answer

The process described in choice C, known as planetary differentiation, explains why terrestrial planets are thought to have dense iron cores. When these planets were in a molten state early in their formation, denser materials, including iron, sank towards the center, while lighter materials floated to the surface. This process resulted in the formation of layered structures with dense iron cores.

Why Is It That Terrestrial Planets Are Thought to Have