E=mc2
DOI: 10.1063/PT.5.031356
On this day in 1905, the journal Annalen der Physik published Albert Einstein’s paper “Ist die Trägheit eines Körpers von seinem Energieinhalt abhängig?” (“Does the inertia of an object depend upon its energy content?”) The term mc² had already made an appearance in his paper of 26 September, which introduced special relativity. The paper of 21 November showed that E = mc² applies to bodies at rest.
Date in History: 21 November 1905