What does radiation not require for heat transfer?

Radiation is a method of heat transfer that does not require a medium, meaning it can occur in a vacuum. This process relies on electromagnetic waves, which can travel through empty space without needing particles to carry the energy. For example, sunlight, which is a form of radiant energy, travels through the vacuum of space and warms the Earth. In contrast, other methods of heat transfer, such as conduction (which requires direct contact between materials) and convection (which requires the movement of fluids), do depend on a medium to facilitate the transfer of heat. Therefore, the notion that radiation does not require a medium is fundamental to understanding how this unique mechanism of energy transfer operates.