How do photons relate to heat transfer by radiation?

Photons play a crucial role in heat transfer by radiation, and they do so by acting as energy carriers that travel at the speed of light. When an object is heated, it emits thermal radiation in the form of infrared photons. These photons can travel through a vacuum or air without needing a medium, allowing them to transport energy from a hot object to a cooler one.

As they travel, these photons carry energy away from the source of heat. This process allows objects to lose heat energy to their surroundings and is fundamental to understanding how radiation works in heating, such as how the sun warms the Earth. Thus, the correct answer emphasizes the speed at which photons travel, which is essentially the speed of light, enabling efficient energy transfer over distances.