Starting at the turn of the century, a series of discoveries challenged the established certainties of Newtonian physics. An important first step toward the new physics was the British physicist J. J. Thomson’s 1897 discovery of subatomic particles, which proved that atoms were not stable and unbreakable. The following year Polish-born physicist Marie Curie (1867–1934) and her French husband, Pierre (1859–1906), discovered radium and demonstrated that it constantly emits subatomic particles and thus does not have a constant atomic weight. Building on this, German physicist Max Planck (1858–1947) showed in 1900 that subatomic energy is emitted in uneven little spurts, which Planck called “quanta,” and not in a steady stream, as previously believed.

In 1905 the German-Jewish genius Albert Einstein (1879–1955) further undermined Newtonian physics. His theory of special relativity postulated that time and space are relative to the observer’s viewpoint and that only the speed of light is constant for all frames of reference in the universe. In addition, Einstein’s theory stated that matter and energy are interchangeable and that even a particle of matter contains enormous levels of potential energy.

In the 1920s breakthrough followed breakthrough, with some discoveries raising new doubts about reality. The implications of the new theories and discoveries were disturbing to millions of people in the 1920s and 1930s. The new universe was strange and troubling, and, moreover, science appeared distant from human experience and human problems.