В 1900 г. родилась квантовая теория Планка

This day physicist Max Planck presented his report on the law of energy distribution in the normal spectrum. Later he wrote that he did not think about establishing a new field of science, he simply wanted to study the black body radiation in more detail. But it turned out that during that research a new field of science emerged. Planck supposed that while radiating or absorbing the energy is released in portions that he called quanta. Planck’s quantum theory was truly revolutionary in physics – now classical physics is referred to as “pre-Planck physics” as opposed to the contemporary state of the science.