Living Book
On the Electrodynamics of Moving Bodies
On June 30, 1905, a 26-year-old patent clerk submitted a paper to Annalen der Physik. No laboratory. No academic position. One friend thanked. Thirty pages. The paper dismantled absolute time, showed that simultaneity depends on who’s measuring, demonstrated that moving clocks run slow and moving objects contract, unified electricity and magnetism, and planted the seed for E=mc². It cited no other physicists. It started with an observation that the existing theory was ugly — it gave two different explanations for the same phenomenon — and ended with a new theory of space and time.
Opens a guided conversation. 5 turns for anonymous visitors.
Major Territories
01The Asymmetry That Started It All
A magnet moving past a conductor and a conductor moving past a magnet produce the same effect — but Maxwell’s theory gives two different explanations. Einstein found this ugly. His fix required abandoning absolute time.
02What Does “Simultaneous” Mean?
Before deriving anything, Einstein dismantles a concept everyone takes for granted. §1 asks what it means for two events to happen “at the same time” — and shows the answer depends on who’s asking.
03Moving Clocks Run Slow
Time dilation isn’t a metaphor. A clock that travels from A to B genuinely lags behind a clock that stayed put. The Lorentz transformations, derived from two postulates.
04Electric and Magnetic Fields Are the Same Thing
The magnet-conductor asymmetry resolved. What one observer sees as electric, another sees as magnetic. The ether was the artifact of insisting they were separate.
05The Patent Clerk
Written by a 26-year-old with no academic position, no laboratory, no citations. The most powerful argument ever made that insight doesn’t require credentials.