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A Stellar Career

Philip Morrison

Henry Norris Russell: Dean of American Astronomers. David H. DeVorkin. xx + 499 pp. Princeton University Press, 2000. $55.

This ample, meticulously professional and expressive biography unfolds the intricate career of Henry Norris Russell, who for five decades led the intellectual and institutional transition in the United States from the astronomical to the astrophysical. As seen through Russell's eyes, the change was from thick tabulations and stacks of exposed photographic plates, painstakingly accumulated, to a science driven by understanding. For him astronomy became applied physics.

Russell was a lifelong Princetonian, the son of a Long Island Presbyterian pastor who had graduated from Princeton Theological Seminary. Henry, fragile and brilliant, went off at age 12 to study at the Princeton Preparatory School and entered the College a month shy of 16. His classmates voted him the brightest man in the class of 1897, although many thought him the most awkward and anxious as well. He graduated insigni cum laude, a rare honor ranking above both summa and magna, and immediately joined the "nascent" graduate program that led to his Ph.D. in mathematical astronomy in 1900. By that time he had already published nine papers.

Henry Norris Russell . . .Click to Enlarge Image

After a postdoctoral stay at the University of Cambridge, the inspired young American came back to the hard work of judging stellar distances from diverse clues. He and the Danish astronomer Ejnar Hertzsprung, working independently, each found their way to what we now call the Hertzsprung-Russell diagram, which involves plotting a star's wattage, fixed by its distance and its brightness, against its spectral color class. Using the diagram, Russell was able to conclude credibly by 1912 that stars of a given color, say red, were of two distinct sorts, nearby dwarfs and far-off giants. That conclusion stands, but Russell was wrong in thinking that stars contract from giant stars to dwarf stars, simply cooling from blue to red; it was eventually discovered that they instead expand swiftly as they age, briefly becoming luminous giants and quickly expending their fuel.

In the mid 1920s Russell began a long campaign for spectrum analysis. Using a result of the Bohr-Sommerfeld school, a vector interpretation that combined electron spin with orbital motion, he suggested a near-classical mechanism for linking spectral terms. Soon he had assembled a wide set of collaborators and observers; these included laboratory spectroscopists, his invaluable compiler Charlotte Moore and a few theorists. Russell's intensity and intuition worked well on the multiple puzzles of spectrum analysis, and he had considerable success with the analysis even of atoms displaying multitudes of lines. By 1929 he had produced his long paper on the atomic composition of the stars. When Edward U. Condon and George H. Shortley's definitive treatise on the quantum mechanics of atomic spectra appeared in 1935, it was dedicated to Russell. It was his victory of useful approximation, reasoned and energetic "practice over principle."

Biographer David H. DeVorkin relies here more on letters, memoirs and archives than on published scientific papers. Russell's professional files held 23,000 letters from him to the many men and institutions he had engaged. He wrote a popular, topical column on astronomy for Scientific American for 40 years. These letters and columns contain much quiet, sharp assessment of people and ideas, and no dearth of Russell's views on matters of religion and philosophy.

In DeVorkin's judgment, Russell was "externally, the surest of individuals," yet internally "tormented by self-doubt and indecision." He was subject to frequent periods of collapse. It is striking that personal papers of his that occupied more than 50 feet of shelf space have been removed from the record by his family.

Russell saw himself as "headquarters scientist" overseeing the few hundred active American professional astronomers of his time, who were at work under a dozen or so privately chosen directors and department heads. He made explicit proposals to the discipline's senior members regarding the tasks the profession should set for itself and the individuals who could do them best. He wielded power through his tireless visiting and pointed letter-writing; his senior authorship of Astronomy, an influential advanced text; and the admiration and support of his best Princeton graduate students throughout their careers.

His letters disclose both the intellectual seriousness with which he advised so broadly and the social constraints under which he did so. Merit was necessary but could not rule. Russell was conservative and plotted no reforms. But he saw talent clearly. In 1934, writing to the new Princeton president, he noted that the best candidate to be groomed to succeed him as director "alas, is a woman!"?Cecilia Payne-Gaposchkin. Russell's celebrated student Harlow Shapley had lured this wonderful student to Harvard on the sound grounds that in Britain she could expect no research career, but he and Russell were themselves years late in acknowledging her value. DeVorkin treats this with nuance.

Russell did not insist that positions of influence be filled by Americans. He made welcome many Europeans, Hans Bethe the youngest among them. At first wary of the nonpareil Subrahmanyan Chandrasekhar, Russell soon judged him outstanding and sought him as a successor, but Chandrasekhar chose to spend his career at the University of Chicago, where he was a remarkably prolific theorist, a cultivated and devoted scholar-citizen, and the decisively formative editor of the Astrophysical Journal. His work was to mean more to the second half of the century than even Russell's had to the first.

Russell was perhaps more sensitive to the prejudice that Chandrasekhar faced as a dark-skinned foreigner than to the sexism that confronted Payne-Gaposchkin. Unfortunately, institutions today still struggle with unreasoning bias.

As a young man, I heard Russell speak once; with his tall, angular stance, white hair, stiffness of manner (and collar), lucid voice and words, he seemed venerable as a cliff. In fact, I am now nearly two decades older than Russell was that day?how ancient I must seem to today's young astronomers!?Philip Morrison, Institute Professor Emeritus, Massachusetts Institute of Technology



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