How did Max Planck’s quantum hypothesis solve the ultraviolet catastrophe?

The ultraviolet catastrophe was a failure of classical physics to explain the spectrum of blackbody radiation. Classical theory, specifically the Rayleigh-Jeans law, predicted that as radiation frequency increased, the emitted energy would increase without limit, implying that objects should radiate infinite energy at high frequencies—an outcome that contradicted experimental observations.12

Max Planck solved this by proposing that energy is not continuous but is instead absorbed and emitted in discrete "chunks" or packets called quanta. He theorized that an oscillator with frequency $\nu$ could only exchange energy in integer multiples of $E=h\nu$, where $h$ is Planck’s constant.123

This hypothesis effectively limited the emission of high-frequency radiation because, at a given temperature, there is insufficient thermal energy available to create these large energy quanta. By restricting the allowable energy levels, Planck’s radiation law matched experimental results perfectly, successfully resolving the discrepancy and laying the foundation for quantum mechanics.21