AN INTELLECTUAL BIOGRAPHY OF HEBER DO UST CURTIS: ONE MAN'S QUEST FOR ASTRONOMICAL CERTAINTY by Miriam E. Carolin A thesis submitted to Sonoma State University in partial fulfillment of the requirements for the degree of MASTER OF ARTS m HISTORY Ste~h en Watrous :;,hard H. Karas r"L l/9o Date • II Copyright 1990 By Miriam E. Carolin .Ill I do not approve the reproduction of this thesis, either in part or in its entirety. Dated s /, I/.? IV AN INTELLECTUAL BIOGRAPHY OF HEBER DOUST CURTIS: ONE MAN'S QUEST FOR ASTRONOMICAL CERTAINTY Thesis by Miriam E. Carolin ABSTRACT Purpose of this Study: From 1917 to 1935, a controversy raged over the identification and location of the spiral nebulae. One faction proposed the spiral nebulae as members of the Milky Way. Their opponents insisted that the nebulae were island universes or galaxies far outside the Milky Way. Heber Curtis, who became known as the leadin~ advocate of the island universe theory, concluded that these nebulae were indeed galaxies, while he was working as an astronomer at Lick Observatory. This paper is an intellectual biography of Curtis and a search for the motivations behind his defense of the island universe theory. Procedure: This study is based on examination of Curtis' private letters, scientific articles, speeches and radio talks. Most of these speeches and talks were made between 1920 and 1938, after the main period of the controversy, hut they reveal his attitude toward the island universe theory. Secondary materials, such as historical treatments of the controversy, were also used. Findings: Heber Curtis steadily advocated the island universe theory of the spiral nebulae regardless of the evidence and worked for its acceptance. He based his conclusions partly on the scientific observations concerning the spectroscopy, space distribution, occulting material, space velocity, novae, rotation and lack of proper motion of the spiral nebulae and analogies between the Milky Way and the spiral nebulae, and in part on his world view, his philosophy of life and on his synthesis of science and religion. v Conclusions: Curtis based his unswervin$ advocacy of the island universe theory on his interpretation of the scientific evidence. His belief in the concepts of order and infinity, his awe at the majesty of the universe and his deep religious conviction also were important contributory factors in his decision. Chair ~t('lo -S-ig_n_J__ u -re~~~ ~~~~~~-----~ M.A. Program: History Sonoma State University VI ACKNOWLEDGEMENTS I would like to thank, first of all, Edgar Morse, without whose support and encouragement, I would not have been able to undertake this thesis. His continuing belief in the value of my subject gave me enough incentive to continue with this project even when I became discouraged, and his guidance was invaluable in assisting me in finding the direction this thesis should take. I would like to give special thanks to the members of my committee, whose patience and understanding eased my task considerably and whose willingness to read the many revisions of this thesis and comment upon them made the task easier for me. Stephen Watrous, as chairman, did far more than could reasonably be expected in helping me bring this project to completion. Richard Karas made extremely cogent comments, which helped greatly to clarify the scientific aspect. Joseph Tenn, the third member of my committee, provided valuable insight into the period and assisted me in keeping my scientific facts accurate. It was in one of Dr. Tenn's courses that I first learned of the subject matter of my thesis. I also wish to thank J.J. Wilson and Ambrose Nichols for their unfailing encouragement during my graduate course of studies. J.J. also edited the fourth chapter of my thesis into a readable form. The Bentley Historical Library at the University of Michigan provided microfilm of Curtis' correspondence and speeches. These provided essential material for my research. I would also like to acknowledge the assistance of the late Mrs. C.D. Shane, curator of the Lick Observatory Archives, for opening archival material on Heber Curtis for me. Last, but definitely not least, I wish to thank Joan Wilbur, who allowed me to use her computer and helped me learn to operate this device. This assistance made working on my thesis much easier than it would have been if I had continued my usual practice of working with a typewriter. f ~ - HEBER DOUST CURTIS 1 AN INTELLECTUAL BIOGRAPHY OF HEBER DOUST CURTIS: ONE MAN'S QUEST FOR ASTRONOMICAL CERTAINTY There is a unity and an integral agreement in the features of the island universe theory which appeals very strongly tome. Heber D. Curtis 2 TABLE OF CONTENTS INTRODUCTION .............................................................................. 3 CHAPTER 1: HISTORICAL BACKGROUND .................................................... 8 CHAPTER2: BIOGRAPHY .................................................................................... 16 CHAPTER3: SCIENTIFIC BASIS FOR CURTIS' POSITION ........................ 29 CHAPTER4: NON-SCIENTIFIC FACTORS INFLUENCING CURTIS .............................................................................................. 41 APPENDICES ................................................................................... 56 CHRONOLOGICAL DEVELOPMENT OF THE ISLAND UNIVERSE CONTROVERSY IN THE TWENTIETH CENTURY ............................................. 57 HEBER CURTIS' EDUCATION AND CAREER ................... 60 HEBER CURTIS' ECLIPSE EXPEDITIONS ............................ 61 BIBLIOGRAPHY ............................................................................. 62 3 INTRODUCTION Curtis led the way in understanding the spirals. Donald Osterbrock1 Since these two 1917 papers by Curtis both specifically mention the island universe theory, it can be seen that Curtis was responsible for res~rrecting the idea and starting the controversy agam. Richard C Hart2 1Donald E. Osterbrock, John R. Gustafson, and W.J. Shiloh Unruh, Eye on the Sky: Lick Observatory's First Century (Berkeley: University of California Press, 1988), 270. 2Richard C. Hart, "Adriaan van Maanen's Influence on the Island Universe Theory" (Ph.D. diss., Boston University, 1973), 29. 4 During the early part of the twentieth century, a controversy concerning the composition and the placement of the spiral nebulae exercised the minds of the astronomical community. Some astronomers contended that these objects were gaseous in nature, probably the first stages of the evolution of stars or of solar systems situated within the Milky Way. Their opponents argued just as forcefully that they were composed of stars and were located far outside the galaxy, that they were island universes. The controversy began in earnest in 1917, when Heber Curtis published articles on novae in spiral nebulae which mentioned the island universe theory.1 Its climax occurred in 1925, when Edwin Hubble, an astronomer at Mt. Wilson Observatory in southern California, produced evidence that the spiral nebulae were indeed located outside the boundaries of our galaxy. The issue was finally resolved in 1935, when Adriaan van Maanen, also an astronomer at Mt. Wilson Observatory, finally conceded that his measurements of the rotation of several of the spiral nebulae were erroneous. His findings had been the major stumbling block to the general acceptance of the island universe theory of the spiral nebulae. Throughout the controversy, Curtis had remained the leading advocate of the theory. This controversy has received considerable attention. Treatments ranging from mention in astronomical histories to an entire book devoted to the subject have appeared within the decades since the dispute ended. Most of these works have approached the subject from an historical point of view mentioning participants as they appeared. This method of studying the controversy is a valid approach. However, it leaves out one aspect of the controversy which might shed some light on the personal side of the story: the human aspect. It is human beings who do science, who think about it and who accumulate scientific knowledge. This knowledge is useless without the interpretation of the men who obtain it. 1Hart, 26-29. 5 Therefore, it seems natural, when writing about an event in the history of science, to concentrate on the scientist or scientists who contributed to the significance of that event. In an attempt to deal with the human aspect of the controversy, this thesis will examine the episode from the point of view of one of the participants, Heber Doust Curtis. He was an astronomer at Lick Observatory when the controversy erupted, and has been credited by at least one historian with bringing about a resurgence of the dispute which resulted in its final resolution.2 Despite that recognition, until recently Curtis has not received much credit for the part he played in the drama. Yet, he saw clearly what the nature and position of the spiral nebulae were, and, in addition, he brought his conclusions to the attention of both the scientific and non-scientific communities as often as he could. Curtis formed his opinion that the spiral nebulae were island universes about 1914. What is remarkable is that, throughout the lifetime of the controversy, when evidence seemed to contradict his view and other astronomers were swayed by seemingly foolproof arguments, Curtis maintained his position as the leading advocate of the island universe theory.3 The only known time Curtis expressed a doubt was with the following statement