The Discovery of Radioactivity

Abstract

One hundred years ago, several remarkable discoveries were crowded into the short space of ten years: x rays in 1895, radioactivity the next year, the electron in 1897, quantum theory in 1900 and special relativity in 1905. Individually, each had enormous significance. Collectively, they heralded what we now know as “modern physics.” Practitioners of the old “classical physics” had no anticipation of the momentous change about to grip their science. Indeed, a few even claimed that all the great discoveries had already been made and that their profession would be reduced merely to measurements of greater and greater accuracy. No doubt some discoveries lay in the next decimal place, as illustrated by the 1894 revelation of the rare gas argon during very accurate measurements of the constituents of air. But a career centered only on making increasingly precise measurements would not have appealed to most physicists.