Which German scientist is credited with the discovery of quantum theory through his work on black body radiation?

Max Planck is credited with the discovery of quantum theory due to his work on black body radiation. In the late 19th century, physicists were struggling to understand how objects emitted radiation, particularly at high frequencies. Classical physics could not adequately explain the observed phenomenon, leading to what was known as the "ultraviolet catastrophe."

In 1900, Planck proposed a revolutionary idea where energy is quantized, meaning it can only be emitted or absorbed in discrete packets, or quanta. He introduced the concept of quantized energy levels and developed Planck's law of black body radiation, which accurately described how bodies emit radiation at different temperatures. This marked a fundamental shift in physics, introducing the idea that energy levels are not continuous, but rather discrete.

Planck's work laid the groundwork for quantum mechanics and significantly influenced subsequent scientists like Einstein and Bohr. The introduction of quantization was essential in explaining various phenomena that classical physics could not address, thus establishing quantum theory as a key pillar of modern physics.