Historical notes on the determination of distance by timed radio waves

Abstract

The discovery of a clearly stratified structure of layers in the upper atmosphere has been––and still is––invoked too often as the great paradigm of atmospheric sciences in the 20th century. Behind this vision, an emphasis––or better, an overstatement––on the reality of the concept of layer lies. One of the few historians of physics who have not ignored this phenomenon of reification, C. Stewart Gillmor, attributed it to––somewhat ambiguous––cultural (or perhaps, more generally, contextual) factors, though he never specified their nature. In this essay, I aim to demonstrate that, in the interwar years, most radiophysicists and some atomic physicists, for reasons principally related to extrinsic influences and to a lesser extent to internal developments of their own science, fervidly embraced a realist interpretation of the ionosphere. We will focus on the historical circumstances in which a specific social and commercial environment came to exert a strong influence on upper atmospheric physicists, and in which realism as a product validating the “truth” of certain practices and beliefs arose. This realist commitment I attribute to the mutual reinforcement of atmospheric physics and commercial and imperial interests in long-distance communications.