Electromagnetic radiation that arises from the thermal energy of an object. It takes two main forms: black-body radiation, and thermal free–free radiation. All objects emit thermal radiation by virtue of their temperature; for many astronomical objects, such thermal radiation will be very similar to black-body radiation. In free–free radiation, the thermal energy of electrons is converted into radiation as they are accelerated past ions. This accounts for much of the radio emission from hot nebulae. See also non-thermal radiation.
Subjects: Astronomy and Astrophysics.