Which method of heat transfer can occur in a vacuum?

Heat transfer through radiation is the correct method that can occur in a vacuum. This is because radiation involves the emission of electromagnetic waves, such as infrared radiation, which can travel through the vacuum of space without the need for a medium. This process is how the Sun’s heat reaches the Earth, demonstrating that radiation can function effectively even when there are no particles to facilitate the transfer of heat.

Conduction requires direct contact between materials and relies on the movement of particles, making it ineffective in a vacuum where there are no particles to transfer energy. Convection involves the circulation of fluids (liquids or gases) to transfer heat, which also cannot occur in a vacuum since there are no fluid particles to move and carry heat away. Insulation, while a technique to reduce heat transfer, does not independently transfer heat and instead relies on the properties of materials to slow down conduction and convection. Thus, the only process that seamlessly operates in a vacuum is radiation.