Objects that are smaller than the wavelength of thermal radiation cannot radiate heat efficiently. A generalized theory of thermal radiation has now been experimentally confirmed at the level of a single object at the Vienna .
Black Body As the temperature of a black body decreases, its intensity also decreases and its peak moves to longer wavelengths. Shown for comparison is the classical Rayleigh–Jeans law and its ultraviolet catastrophe.
Graphical view of Planck's law for a black body (an ideal absorber and emitter). Planck's law states that any body that has a temperature above absolute zero emits electromagnetic radiation at all wavelengths. We can use Planck's law to predict the temperature of a remote body without actually being there, but seeing how much radiance is emitted by it on the spectrum we're scanning on. That's friggin awesome!
Classical physics (Rayleigh–Jeans law, black line) failed to explain black body radiation – the so-called ultraviolet catastrophe. The quantum description (Planck's law, colored lines) is said to be modern physics.