In 1916, Einstein discovered a glitch in his new theory of general relativity. His equations showed that the contents of the universe would not remain static, but instead, they would either expand or contract. As a result, he introduced a “cosmological constant” to his equations to maintain a static universe, a decision he later regretted.
A new study has shed light on the contribution of a little-known Austrian physicist, Friedrich Hasenöhrl, to the development of Einstein’s famous equation, E=mc2. Hasenöhrl’s work on blackbody radiation in a cavity filled with radiation revealed a precursor to Einstein’s equation.
Before Hasenöhrl focused on cavity radiation, other physicists, including French mathematician Henri Poincaré and German physicist Max Abraham, showed the existence of an inertial mass associated with electromagnetic energy. In 1905, Einstein gave the correct relationship between inertial mass and electromagnetic energy, E=mc2, and it was not until 1911 that German physicist Max von Laue generalized it to include all forms of energy.