Robert Dicke and the naissance of experimental gravity physics, 1957–1967

Abstract

The experimental study of gravity became much more active in the late 1950s, a change pronounced enough be termed the birth, or naissance, of experimental gravity physics. I present a review of developments in this subject since 1915, through the broad range of new approaches that commenced in the late 1950s, and up to the transition of experimental gravity physics to what might be termed a normal and accepted part of physical science in the late 1960s. This review shows the importance of advances in technology, here as in all branches of natural science. The role of contingency is illustrated by Robert Dicke's decision in the mid-1950s to change directions in mid-career, to lead a research group dedicated to the experimental study of gravity. The review also shows the power of nonempirical evidence. Some in the 1950s felt that general relativity theory is so logically sound as to be scarcely worth the testing. But Dicke and others argued that a poorly tested theory is only that, and that other nonempirical arguments, based on Mach's Principle and Dirac's Large Numbers hypothesis, suggested it would be worth looking for a better theory of gravity. I conclude by offering lessons from this history, some peculiar to the study of gravity physics during the naissance, some of more general relevance. The central lesson, which is familiar but not always well advertised, is that physical theories can be empirically established, sometimes with surprising results.

The revival of General Relativity at Princeton: Daring Conservatism

“…Elementary particles were found to consist of quarks and gluons, not the fundamental massless fields Wheeler Daring conservatism was a breath of fresh air in a field where many regarded exact solutions as the only sure way to explore the richness of Einstein's theory. In this search 1 His later view was that such conservation laws can be transcended [17]. physical meaning was often secondary, as when it was not clear whether a newlydiscovered solution of the field equations described the same physics as a well-known one in new coordinates.…”

“…Wheeler therefore proposed that nucleon number is carried away by a new radiation he called delta rays [16]. He must have quickly dropped this free invention 1 for the only mention in print is one sentence in Hong-Yee Chu's introductory Report on the Texas Symposium in the conference proceedings [14].…”

“…The history of his contributions has been expertly told by Peebles [1]. Wheeler's path to General Relativity is less familiar (except through his autobiography [2]), and worth telling today.…”

Gravitation and general relativity at King’s College London

“…Throughout the 1960s general relativity was slowly but steadily brought back into the mainstream of physics. The naissance of experimental general relativity was underway (Peebles 2017) and new astronomical observations were changing the attitude of astronomers and physicists to general relativity. Observations of quasi-stellar radio sources (to be quickly become known as quasars) by radio telescopes were complemented by observations in the optical domain.…”

Wired by Weber

“…Then came "Amplification of Microwave Radiation by Substance not in Thermal Equilibrium", 2 Gold, by the way, taught general relativity at the Cavendish Lab in Cambridge UK in 1949-53, so the subject was not completely neglected even in this period of relative disinterest. Peebles (2016) elegantly presents the American recovery of experimental gravity physics elsewhere in this volume. Blum et al (2015) have recently discussed this "low water mark of GR" and its "Renaissance" in the context of an international historiographical framework and with references to a number of other authors and papers who earlier perceived a similar structure to the history.…”