Fergie's Tech Blog

30 June 1905: Einstein Publishes 'On the Electrodynamics of Moving Bodies'

The Annus Mirabilis Papers (from Annus mirabilis, Latin for 'extraordinary year') are the papers of Albert Einstein published in the "Annalen der Physik" journal in 1905. The four articles contributed a large portion of the foundation for modern physics.

Einstein's third paper that year was called "On the Electrodynamics of Moving Bodies" ("Zur Elektrodynamik bewegter Körper", published on June 30, 1905). In this paper, Einstein was able to reconcile Maxwell's equations for electricity and magnetism with the laws of mechanics, by introducing major changes to mechanics close to the speed of light. This later became known as Einstein's Special theory of relativity.

The paper makes no reference to any works that may have led to its development, and mentions the name of one other scientist only, Lorentz. While developing this paper, Einstein wrote to Mileva about "our work on relative motion", and this has led some to ask whether Mileva played a part in its development (as well as the other papers). This paper introduced a theory of time, distance, mass and energy that was consistent with electromagnetism, but omitted the force of gravity.

At the time, it was known that Maxwell's equations, when applied to moving bodies, led to asymmetries, and that it had not been possible to discover any motion of the Earth relative to the 'light medium'.

Einstein put forward two postulates to explain these observations. First, he applied the classic principle of relativity, which stated that the laws of physics remained the same for any frame of reference, to the laws of electrodynamics and optics as well as mechanics. In the second postulate, Einstein proposed that the speed of light remained constant in all inertial frames of reference, independent of the state of motion of the emitting body.

posted by Fergie @ 6/29/2006 10:01:00 PM