In spring 1952, as John Wheeler neared the end of design work for the first thermonuclear explosion, he plotted a radical change of research direction: from particles and atomic nuclei to general relativity.
With only one quantitative observational contact (the perihelion shift of Mercury) and two qualitative ones (the expansion of the universe and gravitational light deflection) general relativity in the early 1950s had become a backwater of physics. It was more a branch of mathematics than of physics, and a not very interesting one. Among the world’s leading physicists at the time, only Wheeler envisioned a future in which curved spacetime would be fundamental to the nature of matter and the astrophysical universe. Because, in his words, “relativity is too important to leave to the mathematicians,” Wheeler set out to discover its roles. Through that quest, over the subsequent two decades, he, his students, and their intellectual descendants...
