A BRIEF HISTORY OF RELATIVITY CHAPTER 1

ALBERT EINSTEIN, THE DISCOVERER OF THE SPECIAL AND

general theories of relativity, was born in Ulm, Germany, in 1879, but the following year the family moved to Munich, where his father, Hermann, and uncle, Jakob, set up a small and not very successful electrical business. Albert was no child prodigy, but claims that he did poorly at school seem to be an exaggeration. In 1894 his father's business failed and the family moved to Milan. His parents decided he should stay behind to finish school, but he did not like its authoritarianism, and within months he left to join his family in Italy. He later completed his education in Zurich, graduating from the prestigious Federal Polytechnical School, known as the ETH, in 1900. His argumentative nature and dislike of authority did not endear him to the professors at the ETH and none of them offered him the position of assistant, which was the normal route to an academic career. Two years later, he finally managed to get a junior post at the Swiss patent office in Bern. It was while he held this job that in 1905 he wrote three papers that both established him as one of the world's leading scientists and started two conceptual revolutions—revolutions that changed our understanding of time, space, and reality itself.  Toward the end of the nineteenth century, scientists believed they were close to a complete description of the universe. They imagined that space was filled by a continuous medium called the "ether." Light rays and radio signals were waves in this ether, just as sound is pressure waves in air. All that was needed for a complete theory were careful measurements of the elastic properties of the ether. In fact, anticipating such measurements, the Jefferson Lab at Harvard University was built entirely without iron nails so as not to interfere with delicate magnetic measurements. However, the planners forgot that the reddish brown bricks of which the lab and most of Harvard are built contain large amounts of iron. The building is still in use today, although Harvard is still not sure how much weight a library floor without iron nails will support.