This year contains two notable scientific anniversaries. The one most widely mentioned is the centenary of Albert Einstein’s three trailblazing papers in the German scientific journal Annalen der Physik on the nature of matter, energy, and motion. Those papers opened up broad new territories for exploration by physicists. The discoveries that followed, and the technology that flowed from those discoveries, helped shape the whole 20th century. Radiation therapy and nuclear weapons, the laser and the personal computer, global positioning satellites and fiber-optic cables — all trace at least part of their lineage to Einstein’s papers. The 20th century was the...