Radiant heat is transferred in the form of electromagnetic waves or particles from a hot object, such as the heating element of your broiler or toaster, to food. This transmission does not need the help of a medium like water or air. The food is heated when it absorbs this radiant energy, which travels at the speed of light (186,000 miles per second).
The sun, too, emits radiant energy. On a subzero January day, it is possible to heat a glass hothouse filled with growing spring vegetables by means of solar rays that have journeyed through a frigid void of 93 million miles.
** Asian Recipes