Final answer:
Whole-mantle convection refers to the movement of heat through the upward movement of warmer material and downward movement of cooler material within a celestial body. In Earth, this drives plate tectonics and shapes the planet's surface. In stars like the Sun, it influences differential rotation and helps in modeling the solar interior.
Step-by-step explanation:
The concept of whole-mantle convection is observed in several astronomical and geological phenomena. It describes the process by which heat escapes from the interior of an astronomical body, such as the Sun or Earth, through the upward flow of hotter material and the sinking of cooler material. This process is essential for understanding both stellar and planetary activities.
In the context of Earth, whole-mantle convection is responsible for driving plate tectonics, significant geological formations, and movements of the Earth's crust and upper mantle. It explains the pattern in which the approximately dozen tectonic plates move apart or come together, powered by the energy of the slowly convecting mantle material.
Similarly, in the context of the Sun, internal convection extends from the surface inward to about 30% of the distance toward the center, affecting the differential rotation observed at the solar surface and guiding our astronomical models. Helioseismology findings leverage this knowledge to build accurate models of the solar interior based on the element abundances observed on the Sun's surface.