What does quantum theory explain black-body radiators?

Quantum theory explains black-body radiators by introducing the concept of quantized energy levels, which led to the understanding of how objects emit and absorb electromagnetic radiation. Classical physics failed to accurately describe this phenomenon, leading to the "ultraviolet catastrophe." Max Planck resolved this by proposing that energy is emitted in discrete packets called "quanta," leading to Planck's law of black-body radiation. This law accurately describes the spectral distribution of radiation emitted by a perfect black body at thermal equilibrium.