The Eccentric Seer of Supernovas

There was little expectation that anything important would occur at the 1933 meeting of the American Physical Society, which began on December 15 in the main lecture room of the physics department at Stanford University. Forty papers were presented to an audience of only 60, an indication of how modest the session was expected to be. The subject that produced the most research was cosmic radiation, now called cosmic rays. It was one of the deeper mysteries to trouble the scientific world at the time. The fact that invisible forces shape our world was still something of a novel concept, so the idea of cosmic radiation flitting around Earth, pushing its way into buildings and penetrating bodies, seemed simply weird.

The radiation—which we now know as the emission of energy from subatomic particles, mostly free-range protons—first appeared in electroscopes, one of the first scientific instruments to chart the effects of electricity. An electroscope consists of a metal rod from which are suspended two gold leaves; when the rod is exposed to a source of electricity, the two leaves repel each other because both leaves have the same charge. But after a time, an unaccountable thing happens: The leaves spontaneously discharge. Each leaf falls back to its original position. Scientists realized some form of radiation was penetrating the chamber and robbing the leaves of their charges. But what was it, and where did it come from?

Some believed the strange radiation came from somewhere far off in space. Others thought there had to be a local source, maybe under the sea, maybe in the still uncharted wilderness of the solar system. Caltech’s Paul Epstein,