Abstract
Jan Hendrick Oort was undoubtedly one of the most influential astronomers of the twentieth century and this biography is most welcome. It is also a challenging but useful semi-encyclopaedic primer for generalist scholars interested in the technical background to the subjects in which Oort engaged, especially the kinematics and dynamics of galaxies, notably our own. The author’s approach, although not completely consistent, is to relate what is known today about a topic and then go into the history of how it became known and into Oort’s contribution to that new knowledge.
van der Kruit quotes heavily and extensively from a variety of sources: Oort’s diaries, family correspondence, commentary by contemporaries, and oral histories, including one I conducted in 1977 (full disclosure). I was both gratified and concerned by the length of the quotes – paragraphs, even pages – but they add colour to the writing. To reach non-specialist readers, the author adds extensive units on basic astronomy, something like selective textbook topics. Although this may be welcomed by some, I feel it takes away from the flow of the biography. In effect, it is more a rambling reader than a cogent disciplined history.
I got the impression that the author inspects every flyspeck on the wall. Many names are mentioned, as are places, times, extensive digressions into backgrounds, and personalities. The author’s colloquial Dutch in English reconstructive prose is charming, almost disarming . . . but also distracting. When identifying Oort’s mother’s middle name as Hannah, a footnote identifies it as the longest palindrome for a girl’s name. And then he adds that the longest palindrome for a boy is “Reinier” (p. 6).
The author also repeats sections and passages from his previous biography of Kapteyn, devoting eight continuous pages to his life. Another 20 pages provide a cultural and scientific background to Leiden, and then he casually slides into how Oort finally arrived there after training under Kapteyn at Groningen and a postdoctoral position with Frank Schlesinger at Yale. He notes that Oort enjoyed his time in the United States working with Schlesinger and would have considered staying. It was not a foregone conclusion that Oort would return to the Netherlands and Leiden. To make this point, the author quotes far more extensively than needed from letters by Oort, DeSitter, and Schlesinger.
The book juxtaposes, in more or less chronological order, Oort’s private and professional life. Oort’s service in World War I gets brief attention and is immediately followed by a chapter titled “Rotation of the Galaxy; Marriage.” We are first treated to a section on absolute declination and latitude. The author mentions Oort’s fundamental astronomy work only briefly, in fact more space is devoted to the technical introduction.
After some 150 pages, we get to high velocity stars and the beginning of his long trail into galactic kinematics. But the author barely gets into it before the next section introduces his future wife, Johanna Maria Graadt van Roggen, in great detail, including quotes from my interview, testimony of Oort’s younger son, and from another set of remarks, uncredited. This goes on for seven pages and when we get back to his work, it is illustrated by four pages of illustrations of their marriage certificate and marriage photos interspersed with a summary of a public lecture given by Oort on “Non-Light-Emitting Matter in the Stellar System” based upon the author’s previous published translations. We slowly learn how Oort challenged the Kapteyn universe and was deeply influenced by the work of Bertil Lindblad. From there, one reads through an extensive display of the steps Oort took to work out the existence of differential rotation in the galaxy, illustrated by faint and hard-to-read reproductions from his notes and calculations.
Next comes a section on “Galactic Structure and Dynamics” with citations from Henri Poincaré and Pelé (Brazilian soccer legend) on, respectively, “order and unity” and “success is no accident.” Here the text and arguments flow more smoothly with equal time given to dynamics and Oort’s growing family. We also learn of the vicissitudes of settling down, debating whether to stay at Leiden or move to Harvard or Columbia, with extensive quotations from letters and images of those letters. Did Oort want to be closer to observational astronomy? Will Johanna Oort resist a move? The answer was yes and yes, and he listened to his wife.
The bulk of the book exhaustively details Oort’s life and career, the topics he chose in galactic dynamics, his rise in the ranks at Leiden to the observatory directorship, the Second World War and recovery, moving into new realms like radio astronomy, his internationalism, trips abroad, the establishment of a major radio facility in Australia, all interspersed with the growth to maturity of his family.
Readers of this journal will probably be familiar with the Springer style. Massive, expensive tomes bound mainly for libraries. Very light copy-editing and too many typos. Yet this work was evidently a labour of love for the author, a former Oort student deeply devoted to his mentor and his legacy. No doubt, it offers invaluable insights and documentation which will be welcomed by specialists.