Definition of thermal radiation
The phenomenon that an object radiates electromagnetic waves due to its temperature. One of 3 ways of heat transfer. All objects whose temperature is higher than absolute zero can generate thermal radiation. The higher the temperature, the greater the total energy radiated and the more short-wave components. The spectrum of thermal radiation is a continuous spectrum, and the wavelength coverage can theoretically range from 0 to ∞. The general thermal radiation mainly depends on the visible light and infrared rays with longer wavelengths. Since electromagnetic waves do not require any medium, thermal radiation is the only heat transfer method in a vacuum.