What process describes the transfer of heat through an empty space?

The process that describes the transfer of heat through an empty space is radiation. This method of heat transfer occurs when energy is emitted in the form of electromagnetic waves, such as infrared radiation, which can travel through a vacuum. Unlike conduction and convection, which require matter to transfer heat (conduction through direct contact and convection through the movement of fluids), radiation does not need a medium and can occur through empty space. This is how the sun warms the Earth, as sunlight travels across the vacuum of space to reach us. Understanding radiation is critical in esthetics, particularly when discussing treatments like LED therapy or infrared treatments, as they utilize this principle to penetrate the skin and produce heat for therapeutic benefits.