Radiation

Thermal radiation is thermal-energy transfer by electromagnetic waves. Unlike conduction and convection, it does **not require a material medium**. Energy from the Sun can therefore cross space and reach Earth. All objects emit thermal radiation. Hotter objects generally emit it at a greater rate. Dark, dull surfaces are usually good absorbers and emitters. Shiny surfaces are good reflectors and relatively poor absorbers and emitters.

Conduction → matter, no bulk flow Convection → moving fluid Radiation → electromagnetic waves