The Physicist Who Predicted That Matter Is a Wave

In 1913, Danish physicist Niels Bohr proposed that electrons orbit atoms in fixed energy levels, where any jump between levels emits or absorbs a photon of light with an energy exactly equal to Planck's constant times its frequency. It was a revolution because it solved two problems. Under the previous model, orbiting electrons would quickly spiral into the nucleus, and also, spectral lines could now be accounted for (at least in light elements). But the model had its limits, and a French aristocrat would ultimately formulate a relation that would both show why Bohr's formula works intuitively, but also would ultimately usher in a new era of physics that would render the Bohr model obsolete.