Remarkably, and despite his findings, when the twentieth century dawned Michelson counted himself among those who believed that the work of science was nearly at an end, with "only a few turrets and pinnacles to be added, a few roof bosses to be carved," in the words of a writer in Nature.
In fact, of course, the world was about to enter a century of science where many people wouldn’t understand anything and none would understand everything. Scientists would soon find themselves adrift in a bewildering realm of particles and antiparticles, where things pop in and out of existence in spans of time that make nanoseconds look plodding and uneventful, where everything is strange. Science was moving from a world of macrophysics, where objects could be seen and held and measured, to one of microphysics, where events transpire with unimaginable swiftness on scales far below the limits of imagining. We were about to enter the quantum age, and the first person to push on the door was the so-far unfortunate Max Planck.
In 1900, now a theoretical physicist at the University of Berlin and at the somewhat advanced age of forty-two, Planck unveiled a new “quantum theory,” which posited that energy is not a continuous thing like flowing water but comes in individualized packets, which he called quanta. This was a novel concept, and a good one. In the short term it would help to provide a solution to the puzzle of the Michelson-Morley experiments in that it demonstrated that light needn’t be a wave after all. In the longer term it would lay the foundation for the whole of modern physics. It was, at all events, the first clue that the world was about to change.