Astronomy/Thermal Radiation

All objects with a termperature above absolute zero emit heat in the form of electromagnetic radiation. As the atoms are shaken by random thermal motion, the moving charge of the electrons causes them to emit a changing electromagnetic field. The spectrum and intensity of the emitted radiation can be used to determine the object's temperature from a distance. If a material is heated above 700 Kelvins, it begins to glow visibly - starting out as a dark red color and moving towards the blue end of the spectrum with increasing temperature.