Cosmology

Abstract

We begin this chapter by recalling the basic features of physics that are important in astronomy. The first three decades of the twentieth century were the most remarkable and revolutionary in the history of civilization, and, most certainly, in the history of science. By the year 1930 all the great revolutions in the physical sciences had been completed. Max Planck had propounded his law of blackbody radiation; Einstein had presented his special theory of relativity, his theory of the photon, his famous formula E = mc ², his explanation of the photoelectric effect, his introduction of the concept of the corpuscle-wave dualism; and, in 1915, he had presented his general theory of relativity, which was to usher in cosmology in the 1930s. In parallel developments, Heinrich Hertz had verified experimentally Clerk Maxwell’s electromagnetic theory of light, Sir J.J. Thomson had discovered the electron and proton, Ernest Rutherford had brought order into the theory of radioactivity, and had proved experimentally that the atom has a nuclear structure, with a positively charged, compact nucleus at its center surrounded by a revolving cloud of negatively charged electrons, with one electron for each positive charge on the nucleus.

And God said: “Let there be light,” and there was light.

—Genesis