This is the first in a series of posts that will cover the outcome of the 4 fundamental papers published by Albert Einstein in 1905, the so-called “Annus Mirabilis”, or miracle year. This article was originally published at the sent2null blog and is reposted here courtesy of David Saintloth. The remaining 3 posts in the series are to follow.
1905 was a great year for physics – in this year a 24 year old patent examiner in Bern, Switzerland published 4 fundamental physics papers in 4 disparate areas of the field. The topics included special relativity, the relationship between energy and matter, Brownian motion, and the subject of this post, the photoelectric effect.
Next to his paper on Brownian motion, Einstein’s paper on the photoelectric effect was probably the most practical: it provided an answer to a long-standing problem in electromagnetic theory at the time that had stood as an embarrassment to particle physics. This embarrassment was a legacy of the work of James Clerk Maxwell and his fundamental equations of electromagnetism: by using a continuous wave analog to describe the energy of propagating fields, Maxwell was able to astonishingly explain the riddle that was the relationship between electricity and magnetism in clear mathematical terms. He was also able to show how light itself must be an electromagnetic wave, by showing that all such waves are limited by the speed of light (c), roughly 186,000 miles per second.