Resurrecting Maunder’s ghost: John ‘Jack’ Eddy, the Maunder Minimum, and the rise of a dilettante astrophysicist

Abstract

During the 1970s, widespread scientific interest in the risks of climate change prompted John A. Eddy (1931-2009), an astrophysicist with the National Center for Atmospheric Research in Boulder, CO, to investigate whether sunspots could be used to predict future climate changes. Methodologically, Eddy's investigations were uniquely historical in nature. By interrogating old manuscripts of solar observations since the early seventeenth century, he identified what appeared to be a correlation between the so-called Maunder Minimum - a virtual cessation of sunspots between 1645 and 1715 - and severely cold temperatures during the Little Ice Age. While he could not identify the physical mechanisms that governed solar-climate relationships, this historical episode fostered his curiosity. Fortuitously, Eddy's solar-climate research coincided with efforts to use satellites to monitor and record variations in solar energy output, which in context constituted a significant development in managing environmental and technological risk. But using the Maunder Minimum to advance the frontiers of knowledge about solar-terrestrial relationships was not Eddy's only - or even primary - motivation. In the mid-1840s, German astronomer Heinrich Schwabe (1789-1875) discovered what appeared to be a decadal sunspot cycle, the existence of which inspired generations of astrophysicists to more precisely estimate its length as well as determine its underlying causes. Eddy, however, came to believe that the astronomical community failed to consider the implications of subsequent evidence suggesting that Schwabe's solar cycle was not an enduring characteristic of the sun. Instead, he reasoned that evidence offered by nineteenth-century European astronomers Gustav Sporer and Edward Maunder in the 1880s and 1890s had been entirely overlooked. But rather than arguing that their evidence was overlooked in error, Eddy identified what he cast as a conspiracy of wilful ignorance on the part of a staid and conservative astronomical community. By utilizing Eddy's private hand-written notes as they appeared in undergraduate lectures, public speeches and academic talks, as well as his appreciation for the seminal views of sociologist of science Thomas Kuhn, I show that Eddy sought to rectify this injustice by proposing a contrasting vision of science as an interdisciplinary, collaborative and creative process of exploring the ignored areas between scientific disciplines.