SOLAR SYSTEM

Detailed explanation-1: -Heat is transported by conduction in the crust where the material is rigid and cannot flow, and the temperature gradient is high. Conduction is very efficient in some materials like metals, and inefficient in others like air. Inefficient conductors are called insulators.

Detailed explanation-2: -Thermal convection, the buoyant upflow of hot material and the sinking of negatively buoyant cold material, is the principal mode of heat transfer in the mantle.

Detailed explanation-3: -The lower mantle is heated directly by conduction from the core. In conduction, heat is transferred as atoms collide. The rising and sinking of warm and cooler material is called convection. Conduction brings hot material up toward the surface.