Säteilylämpömi

Säteilylämpömi, often translated as radiant heat, is a form of heat transfer that occurs through electromagnetic waves. Unlike conduction or convection, radiant heat does not require a medium to travel and can propagate through a vacuum. The primary source of radiant heat for Earth is the sun.

All objects with a temperature above absolute zero emit thermal radiation. The intensity and wavelength distribution of this radiation depend on the object's temperature and its emissivity. Hotter objects emit more radiation, and at shorter wavelengths. This is why a heated piece of metal glows red, then orange, and eventually white as its temperature increases.

Examples of radiant heat are abundant in everyday life. The warmth felt from a campfire or a radiator is due to infrared radiation. Sunlight warming your skin is another example. Ovens and toasters use radiant heat elements to cook food. Understanding radiant heat is crucial in fields such as thermodynamics, thermal engineering, and even in designing efficient buildings. Materials that are good absorbers of radiant heat tend to be dark and matte, while good reflectors are typically light and shiny. This principle is used in insulation and reflective coatings.