The primary mechanism by which energy is transferred in a vacuum is through radiation. Unlike conduction and convection, which require a medium (solid, liquid, or gas), radiation allows for the transfer of heat in the form of electromagnetic waves. This principle is vital for understanding how the sun's energy reaches the Earth, influencing climate and weather patterns. Radiative transfer is also important in various technologies, including solar energy systems and thermal insulation, where controlling heat loss or gain is essential.