The Legacy of 1900-1949

In the first half of the twentieth century, modern physics emerged out of a watershed of theory and discovery concerning the realm of the atomic nucleus and subatomic energies and speeds. From the profound insights of Albert Einstein's (1879-1955) relativity to the compartmental order of Max Planck's (1858-1947) quantum theory and its antecedent quantum mechanics, humanity was upon the threshold of an atomic age. Likewise, chemists also delved into the study of atomic structure following ground-breaking investigations of chemical reactions and equilibrium laws, new elemental gases, radioactive elements, their isotopes and chemistry, and atomic weights. Shared areas of study included surface chemistry, molecular structure, chemical bonding, and the synthesis of new radioactive elements.

In contrast to study of the physically infinitesimal, study of the vast universe advanced through the use of large aperture telescopes, beginning at Mount Wilson...