Abstract
The year 2019 marked the first centenary of the expeditions coordinated by Frank Dyson and Arthur Eddington to observe the eclipse of 29 May 1919, with the goal of testing the theory of general relativity. As is well known, the eclipse provided a good opportunity to measure the deflection of starlight due to the gravitational field of the Sun, and to compare the results with Newtonian and relativistic predictions. One group went to Sobral in Brazil and the other, led by Eddington himself, to the island of Principe, off the west coast of Africa. The results proved overall favourable to general relativity, catapulting Albert Einstein to scientific stardom.
This story is revisited by Nuno Crato and Luís Tirapicos in Einstein’s Eclipse: From Lisbon and London to Sobral and the Island of Principe, a bilingual volume in Portuguese and English. The Island of Principe was under Portugal’s colonial domain at the time; research carried out by Ana Simões and collaborators at the University of Lisbon has lifted the veil on the support given to Eddington’s party by Portuguese astronomers and institutions. Their work provided an academic backdrop to several commemorative events and initiatives held in 2019 in Portugal and in the island of Principe to mark the centenary of Einstein’s eclipse.
Einstein’s Eclipse grows out of this context. It is part of a series of collectible books covering varied topics and maintained by CTT–Correios de Portugal, the national postal service of Portugal. The print run is limited to 4000 copies, each individually numbered and providing a set of three postal stamps especially issued to celebrate the 1919 eclipse. In line with the general format of the series, Einstein’s Eclipse is lavishly illustrated with photographs, scans of historical documents, and carefully designed graphics explaining particular concepts and phenomena.
Although the book’s layout offers an original presentation of its topic, the narrative style is more traditional. Einstein’s Eclipse delivers a linear story of scientific triumph, from the early development of the theory of general relativity to the recent detection of gravitation waves, with the 1919 eclipse featuring as the decisive event that placed the theory on a solid observational footing while propelling Einstein to global fame. The narrative is concise, solid, and well informed; the approach is understandable, given the nature and context of the book’s format and production.
A less accomplished part of Einstein’s Eclipse is the authors’ take on the controversies surrounding the 1919 expeditions and their results. Einstein, Eddington, and other major players highlighted in the book are by no means jeopardized historical figures in need of a reputation repair, and one wonders why Crato and Tirapicos seemingly felt obliged to defend them from the critiques of authors such as Harry M. Collins and Trevor Pinch. Allegedly enticed by the deconstructive tenets of post-modernism, these authors in the 1990s questioned the consistency and reliability of the results obtained by the British eclipse expeditions of 1919. While this controversy is part of the intellectual history of “Einstein’s eclipse” and as such deserves a reference, a special section on post-modernism, chastising these authors, seems misplaced in an otherwise well-balanced book. The so-called “science wars” have had their heyday and there is no benefit in retrieving platitudes such as “the mechanics of Aristotle cannot build aeroplanes [sic], but the mechanics of Newton are able to send satellites into orbit” (p. 156).
Much more interesting are the references to the Portuguese and Brazilian scientific communities and institutions of the period and to their dealings with the British expeditionaries. In this regard, it is worth highlighting the material on the Portuguese context, which not surprisingly is addressed in considerable detail and finely illustrated with photographs of the Astronomical Observatory of Lisbon and its instruments, as well as scans and excerpts of the correspondence exchanged between Eddington and the Lisbon astronomers and other historical documents.
Overall, Einstein’s Eclipse is a nicely crafted collector’s book dealing with a major event in twentieth-century science and bringing to light materials that may be lesser known by international readers. Those willing to add a copy to their libraries should waste no time in ordering one while they last.