- Heat can be transferred by three main mechanisms: conduction, convection, and radiation. - Conduction requires direct contact between objects or particles. - Convection involves heat transfer through the movement of fluids (liquids or gases). - Radiation involves the transfer of energy through electromagnetic waves. This process does not require a medium and can occur through a vacuum. - The space between the sun and the Earth is largely a vacuum. Therefore, the heat from the sun reaches us primarily through radiation.