In 1900, the German physicist Max Planck proposed a bold and innovative resolution to the ultraviolet catastrophe. He reasoned that the problem was that the formula predicted low-wavelength (and, therefore, high-frequency) radiancy much too high. Planck proposed that if there were a way to limit the high-frequency oscillations in the atoms, the corresponding radiancy of high-frequency (again, low-wavelength) waves would also be reduced, which would match the experimental results.

Planck suggested that an atom can absorb or reemit energy only in discrete bundles (*quanta*). If the energy of these quanta are proportional to the radiation frequency, then at large frequencies the energy would similarly become large. Since no standing wave could have an energy greater than *kT*, this put an effective cap on the high-frequency radiancy, thus solving the ultraviolet catastrophe.