On June 30, 1905, Albert Einstein publishes “Zur Elektrodynamik bewegter Körper (On the Electrodynamics of Moving Bodies),” a paper that sets out his theory of special relativity, in the German physics journal Annalen der Physik. Einstein’s groundbreaking work shatters the foundations of physics.

After attending the Federal Polytechnic School in Zurich, Switzerland, Einstein worked at the Swiss patent office in Bern from 1902 to 1909. He was employed as a "third- class technical expert," examining inventions for their patentability, most likely among them a gravel sorting machine and a weather indicator. In a letter to his friend Michele Besso, Einstein regarded the patent office as “that secular cloister where I hatched my most beautiful ideas.”

The most profound of these ideas emerged in five theoretical papers written in quick succession in 1905 that would revolutionize 20th- century scientific thought. Historians would later refer to this period as Einstein’s annus mirabilis, or “miracle year.” His first paper described the particle theory of light, which would later earn him the 1921 Nobel Prize in Physics. His second created a new method for determining molecular sizes, and his third examined Brownian motion, offering a mathematical explanation for the movement of particles suspended in a fluid.

Einstein’s fourth paper, often regarded as one of the most important papers ever published in the field of physics, presented his special theory of relativity, overturning long-established views of the universe that had prevailed since Isaac Newton introduced his laws of motion. “Time,” Newton wrote, “flows equably without relation to anything external,” while space “remains always similar and immovable.” Einstein’s radical theory, however, posited that time and space are not absolute, but relative to the motion of the observer.

Suppose there were two observers; one stood still along a train track, while the other traveled by train at a constant speed, seated in the middle of the train. If lightning struck both ends of the train just as the train’s midpoint passed the stationary observer, then it would take the same amount of time for the light from each strike to reach the observer. He would correctly assume that the lightning strikes had occurred simultaneously. The train passenger, however, would view the events differently. With the speed of light remaining constant, light from the rear strike would appear later than light from the front strike. This is because light from the rear strike had to travel a greater distance to reach the passenger since she was moving away from where the rear strike occurred and towards where the front strike happened. Therefore, the passenger would perceive that the two lightning strikes were not simultaneous, and would also have been correct.

In September, Einstein published a fifth paper with a mathematical exploration of special relativity: E=mc2, with energy (E) equal to mass (m) times the speed of light (c) squared (2). What would become the most famous equation in the world posited that mass and energy are interchangeable and are different ways of measuring the same thing. This discovery had far-reaching consequences, and set the stage for nuclear power and the eventual development of the atomic bomb, for which Einstein had no direct involvement. In fact, while initially a supporter of America developing an atomic bomb, Einstein came to wholeheartedly renounce that support.