For nearly three decades, the two most famous physicists of the twentieth century argued about whether quantum mechanics was telling the truth about the universe — not about its equations, which both men accepted, but about what those equations meant. Albert Einstein thought the theory was a triumph and also, somehow, incomplete: a magnificently useful…
In the summer of 1925, a 23-year-old German physicist retreated to a treeless, wind-scoured rock in the North Sea to escape a bad case of hay fever, and came back with the mathematics that would end classical physics’s two-century run. Within eighteen months, a rival formulation appeared from Zurich built on entirely different ideas, the…
In March 1913, a 27-year-old Danish physicist sent Ernest Rutherford, his former supervisor in Manchester, a paper that shouldn’t have worked. It borrowed a strange, unproven idea from Max Planck’s theory of heat radiation and welded it onto Rutherford’s own nuclear atom, and in doing so it explained something no one had been able to…
In 1909, a nineteen-year-old undergraduate at the University of Manchester was handed an experiment nobody expected to produce anything. Ernest Rutherford told him to check whether alpha particles, fired at a thin sheet of gold foil, ever bounced straight back. They weren’t supposed to. The prevailing model of the atom offered no mechanism for it….
In the spring of 1905, a twenty-six-year-old patent examiner in Bern, Switzerland, was reviewing applications for mechanical inventions during the day and rewriting the foundations of physics at night. He had no laboratory, no university post, and no research group. What he had was a stack of unresolved problems that the physics of the nineteenth…
In December 1900, a cautious, deeply conservative Berlin physicist stood before the German Physical Society and proposed an idea he did not fully believe himself. He suggested that energy, at least when it comes to how hot objects radiate light, is not smooth and continuous, as everyone had always assumed. It comes in discrete chunks….
By 1900, physics had a problem most fields would envy: it looked finished. Two centuries of work by Isaac Newton, James Clerk Maxwell, and the physicists who built on them had produced a picture of the universe so complete that some of the era’s leading scientists genuinely wondered whether there was anything major left to…
For most of scientific history, atoms were a guess dressed up as a philosophy. The idea that matter is built from tiny, indivisible units goes back to ancient Greece, but for over two thousand years nobody had a way to actually check it. That changed between 1803 and 1908, when a self-taught English chemist, a…
By 1861, physicists had three separate, well-tested subjects on their hands: electricity, magnetism, and optics. Each had its own laws, its own instruments, its own experts. James Clerk Maxwell looked at Michael Faraday’s rough, unmathematical picture of invisible “lines of force” filling the space around a magnet or a charge, translated it into a rigorous…
For most of human history, electricity was a party trick. Rub amber with fur and it would tug at bits of straw; that was about the extent of anyone’s understanding. By 1873, electricity and magnetism had merged into a single mathematical theory that also explained light itself. The path between those two points runs through…
