By the late nineteenth century, engineers and experimental scientists generally knew how radio waves behaved, and by 1901 scientists were able to manipulate them to transmit messages across long distances. What no one could understand, however, was why radio waves followed the curvature of the Earth. Theorists puzzled over this for nearly twenty years before physicists confirmed the zig-zag theory, a solution that led to the discovery of a layer in the Earth’s upper atmosphere that bounces radio waves earthward—the ionosphere.
In Probing the Sky with Radio Waves, Chen-Pang Yeang documents this monumental discovery and the advances in radio ionospheric propagation research that occurred in its aftermath. Yeang illustrates how the discovery of the ionosphere transformed atmospheric science from what had been primarily an observational endeavor into an experimental science. It also gave researchers a host of new theories, experiments, and instruments with which to better understand the atmosphere’s constitution, the origin of atmospheric electricity, and how the sun and geomagnetism shape the Earth’s atmosphere.
This book will be warmly welcomed by scholars of astronomy, atmospheric science, geoscience, military and institutional history, and the history and philosophy of science and technology, as well as by radio amateurs and electrical engineers interested in historical perspectives on their craft.
“Chen-Pang Yeang’s book is the major contribution to our knowledge of how physical theory and electrical experimentation worked together to explain the movement of radio waves beyond the horizon—a compelling question in the years following Marconi’s famous experiment of 1901. Yeang clearly explains how ‘direct evidence’ for the existence of the ionosphere was ultimately provided and reminds us of how important work in classical physics continued into the exciting era of relativity and quantum mechanics. What he describes is a rare mix of physics and electrical engineering encountering the ‘field sciences.’”
— A. David Wunsch, University of Massachusetts Lowell
“Probing the Sky with Radio Waves offers us a fine example of the ‘mutual shaping’ of science and technology. Those interested in a thoughtful, technically adept history of the discovery of the ionosphere will not be disappointed. Yet this book offers much more. Chen-Pang Yeang deftly draws out the diverse international array of local cultures that made the discovery possible: mathematical, theoretical, and experimental physicists; civilian, military, and corporate engineers; inventors and radio amateurs. The story is a fascinating one, and Yeang—coupling the history and philosophy of science—is an able narrator.”
— Suman Seth, Cornell University
“The advent of global radio communications marked the beginning of three decades of intense theoretical and experimental studies of the ionosphere. Yeang’s work is a philosophically sophisticated examination of the interplay between theory and practice in the early years of radio science. Definitive experiments in the 1920s intentionally bounced radio waves off the ionosphere to probe its structure, and Yeang fits the history of the complex evolution of ionospheric studies into the wider contact of active sensing. . . . Highly recommended.”