A Labor of Love: The Renaissance of Astronomy by Noel Swerdlow Has Been Published Posthumously with Help from Friends and Colleagues

Noel Swerdlow, a renowned historian of science, spent nearly a decade at Caltech as a visiting associate following his retirement from the University of Chicago in 2010. The world's foremost expert on Copernicus—one of the most important contributors to premodern astronomy—Swerdlow passed away in 2021, but his legacy lives on in a new book thanks to Jed Buchwald, the Doris and Henry Dreyfuss Professor of History at Caltech.

The Renaissance of Astronomy, published in May, is a comprehensive account by Swerdlow of the works of Regiomontanus, Copernicus, Tycho Brahe, Johannes Kepler, and Galileo, five key astronomers from the Renaissance period who replaced the geocentric model of the planetary system formalized by Ptolemy, in which Earth is fixed in space as the center of our solar system, with a heliocentric one that positions the Sun at the center. Swerdlow had been working on the book for many years, but it was left unfinished when he died, Buchwald says.

"Noel was one of my oldest friends, and many years ago, I and others urged him to write a comprehensive account of Renaissance astronomy," recalls Buchwald, who is the editor of a series titled Sources and Studies in the History of Mathematics and Physical Sciences. "He worked almost exclusively on the project for many years. In his last weeks and months, I made sure that we had all his drafted works and told him that it would be published in Sources and Studies, which in 1984 included the prize-winning study of Copernicus that he had written in collaboration with the legendary historian of ancient mathematics and astronomy, Otto Neugebauer."

The result is a 1,100-plus page tome that provides a rigorous exploration of the work of the figures who laid the foundations of modern astronomy.

"For the first time, we have a clear understanding of the ways in which the works of these astronomers fit together to produce a deep and novel change in the structure of observation and mathematical understanding," Buchwald says. "Swerdlow's book is a coherent portrait deeply grounded in detailed technical and cultural understanding of the individuals of this most significant period in the development of what evolved into modern science."

But completing the book was no easy task. Buchwald worked with Swerdlow's former student, Anthony Grafton, the world's leading expert on Renaissance humanism and professor of history, emeritus, at Princeton University. They called on friends and colleagues to pull together missing pieces, such as a bibliography of primary and secondary sources and a bibliography of Swerdlow's work; provide a copy edit of the text; and even help finish a chapter on Brahe, a Danish astronomer who helped launch the Scientific Revolution in the 16th century. The book's editing process took four and a half years.

While much of the book relies on Swerdlow's deeply researched personal writing, it also contains numerous translations by him of significant works.

"One of the works included at the beginning of the book is a beautiful translation by Noel of one of the greatest orations on the nature of astronomy in the 1400s by Regiomontanus, the leading mathematical astronomer of 15th-century Europe" Buchwald says. "I think he particularly liked it because Regiomontanus sounds like a 600-year-old version of Noel."

In addition to original text and translations, the book contains a trove of charts and illustrations.

"There are marvelous stories and accounts of the individuals, while the technical material includes diagrams, tables, equations, even contemporary horoscopes that were drawn up in their times for each of the scientists," Buchwald explains.

Getting the supplemental pieces into shape represented yet another challenge for Buchwald and Grafton, but he is confident that the result was worth it.

"It is a magnificent book for the ages," Buchwald says. "Anybody interested in the origins of not just astronomy but of modern science will want at least to dip in. Noel's magisterial account will surely be looked at not just for decades, but for centuries, as was an early 19th-century history by the astronomer and mathematician Jean Baptiste Joseph Delambre."

Published by Springer Nature, The Renaissance of Astronomy is available as an e-book and in two printed volumes.