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1 A Scientific Autobiography: S. CHANDRASEKHAR

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3 A Scientific Autobiography: S. CHANDRASEKHAR Edited by Kameshwar C. Wali Syracuse University, USA World Scientific NEW JERSEY LONDON SINGAPORE BEIJING SHANGHAI HONG KONG TAIPEI CHENNAI

4 Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore USA office: 27 Warren Street, Suite , Hackensack, NJ UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. Cover credit: Subrahmanyan Chandrasekhar in his office at the University of Chicago, standing beside a picture of Sir Isaac Newton placed on the volumes of the Principia Mathematica, March Photograph courtesy of Spenta Wadia. Anecdote connected with this photo is at A SCIENTIFIC AUTOBIOGRAPHY: S. CHANDRASEKHAR Copyright 2010 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN ISBN X ISBN (pbk) ISBN (pbk) Printed in Singapore.

5 DEDICATION Lalitha Chandrasekhar v

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7 FOREWORD In late 1980 s, while I was working with Chandra on his biography, he mentioned a journal he kept of his scientific activities. One day he handed me a copy of what he had at the time. It was supposed to be confidential, and after his death, if his wife Lalitha and I thought it of interest and worthwhile, he would like to see it published. A brief glance at it evoked wonder and admiration. Chandra led a life of supreme and almost unparalleled effort in unraveling the laws of nature encoded in mathematics. The year 2010 marks Chandra s birth centennial (October 19, 1910) and seems the perfect time to bring to light this unique document, A Scientific Autobiography. The journal gives a rare and personal insight into the joys and struggles of a brilliant scientist at work. For example, on his work on Radiative Transfer with which this journal begins, Chandra said, My research on radiative transfer gave me the most satisfaction. I worked on it for five years, and the subject, I felt, developed on its own initiative and momentum. Problems arose one by one, each more complex and difficult than the previous one, and they were solved. The whole subject attained elegance and a beauty which I do not find to the same degree in any of vii

8 viii A Scientific Autobiography: S. Chandrasekhar my other work. And when I finally wrote the book, Radiative Transfer, I left the area entirely. Although I could think of several problems, I did not want to spoil the coherence and beauty of the subject [with further additions]. Furthermore, as the subject had developed, I also had developed. It gave me for the first time a degree of self-assurance and confidence in my scientific work because here was a situation where I was not looking for problems. The subject, not easy by any standards, seemed to evolve on its own. a It is this kind of insight that illuminates the contextual circumstances surrounding his body of work and gives it a depth of purpose we could not know otherwise. As revealed in this scientific autobiography, and as Chandra himself noted in the autobiographical account published with his Nobel Lecture: After the early preparatory years, my scientific work has followed a certain pattern motivated, principally, by a quest after perspectives. In practice, this quest has consisted in my choosing (after some trials and tribulations) a certain area which appears amenable to cultivation and compatible with my taste, ability, and temperament. And when after some years of study, I feel that I have accumulated a sufficient body of knowledge and achieved a view of my own, I have the urge to present my point of view ab initio, in a coherent account with order, form, and structure. This autobiography is a testimony to his having carried out his quest to its perfection. The inner workings described in this document go beyond the vast landscape of physics, astrophysics and applied mathematics. Chandra s published papers and monographs evoke a feeling of respect and wonder. While to a casual student it may seem intimidating and forbidding, for the serious-minded, however, they leave an indelible impression of their endearing value in spite of the continual progress in the respective fields. They convince one of the innate values of science the continuity, the interdependence, and the necessity of combining original research with scholarship. As we read, we find that with the perspective gained in one area to his satisfaction, he leaves that area entirely and proa Chandra; A Biography of S. Chandrasekhar, University of Chicago Press, 1991, p. 190.

9 Foreword ix ceeds to another with a complete sense of detachment, ready to start afresh in a new area. If it was necessary, he would attend classes, take notes, and studied as if he were once again a student. Or he would teach a course, and perhaps would give a series of lectures on the topic he wanted to learn. On the drop of a hat, he would fly to Oxford, England to have a discussion with Roger Penrose, or to Crete and Rome to work with his young collaborators, Basilis Xanthopoulos and Valeria Ferrari. In addition, this autobiographical journal reveals Chandra s human side, the man behind the legend his intense association with his students and associates and his ability to inspire in others hard work and enthusiasm. Chandra s extraordinary personality was characterized by an intensity and fervor for completeness, elegance, and above everything else, gaining a personal aesthetic perspective. It extended beyond his technical scientific publications to his semipopular lectures and essays. This is best illustrated, as he tells us in this autobiography, how he was led to writing the essay, The Series Paintings of Claude Monet and the Landscape of General Relativity, in which he speaks about the similarity of Monet s motivations in painting his Series Paintings b and his own motivations in the series of papers on black holes, colliding waves and scattering of gravitational radiation. In Monet s paintings, the same scene is depicted over and over again under different natural illumination and seasonal variations. The valley, the trees and the fields, and the haystacks are the same. Superficially, they may appear boring and repetitive. However, the different paintings radiate totally different aesthetic content. When seen as a group, a viewer can obtain a deeply convincing sense of the continuous nature of the experience in contrast to the shifting nature of what one observes. In a similar fashion, the same set of static symbols, which form the landscape of General Relativity, manifest in different roles in equations, unifying the description of vastly different physical phenomena, making the General Relativity as sometimes described as the one of the most beautiful theories. b Chandrais referring to: (1)Haystacks (orgrainstacks), (2)Poplars, (3) Early morning on the Seine.

10 x A Scientific Autobiography: S. Chandrasekhar In concluding that essay, Chandra states he does not know if there has been any scientist who could have said what Monet did on one occasion I would like to paint the way a bird sings. But we do know of a scientist who spoke like a poet on one occasion The pursuit of science has often been compared to the scaling of mountains, high and not so high. But who amongst us can hope, even in imagination, to scale the Everest and reach its summit when the sky is blue and the air is still, and in the stillness of the air survey the entire Himalayan range in the dazzling white of the snow stretching to infinity? None of us can hope for a comparable vision of Nature and the universe around us, but there is nothing mean or lowly in standing below the valley below and waiting for the sun to rise over Kanchenjunga. With such writings, often filled with parables, quotes from modern and ancient literature, with his Ryerson Lecture, Shakespeare, Newton and Beethoven and his book, Truth and Beauty, Chandra bridged the gap between what C.P. Snow calls the two cultures the culture of sciences and of the humanities. This scientific biography, mainly concerned with an intense effort to understand Nature in the language of mathematics, may superficially seem too specialized and forbidding. But it should be no more forbidding than a memoir of a painter, who struggles with his tools, his trials and tribulations to attain his vision or of a great writer who creates characters and situations beyond one s ordinary imagination, bringing unexpected joy and insight.

11 Foreword xi In early summer of 1995, I had my last conversation with Chandra. I had received a complementary copy of his last book, Newton s Principia for the Common Reader directly from the publisher. I thanked him for it. He was annoyed that it took so long for it to besent. Hecomplained about getting weak, and his inability to do hard work and needed help to get back to his apartment after a walk. I reminded him, the days were extremely hot in Chicago at the time and that he should take care. I admonished him for working so hard. Take it easy, relax. Yes, that is what I am doing, he said. I am reading Les Misérables by Victor Hugo. Chandra died on August 21, 1995 at the age of 84. The years I spent working with Chandra and writing his biography were the most enjoyable and the creative years of my life. As I sat with him in his office, among the books, journals, files of correspondence and sketches, conversing sometimes hours at a time, I often became transformed, and caught a glimpse of the incomparable world which Res Jost so aptly described: There is a secret society whose activities transcend all limits of space and time, and Dr. Chandrasekhar is one of its members. It is the ideal community of geniuses who weave and compose the fabric of our culture. c It is indeed a privilege and honor to present for publication this scientific autobiography which evokes an enduring self-portrait of the man behind science. Acknowledgements I am grateful to Daniel Meyer and the staff at the Special Collections Research Center of the University of Chicago Library for providing me copies of the documents reproduced in this volume. c Jost, a noted Swiss physicist, on the occasion of awarding Chandra, the Tamala Prize on January 9, 1984 in Zurich, Switzerland.

12 xii A Scientific Autobiography: S. Chandrasekhar Thanks to Monona Wali for editing parts of this book and Heather Kirkpatrick for preparing the manuscript. Finally, I would also like to thank the Senior Editor, Lakshmi Narayanan and her colleagues at World Scientific for the excellent job in producing this volume. Kameshwar C. Wali October 2010

13 Preface It is unlikely that I shall add any further instalments to this scientific autobiography that I have written at intervals during the past forty years. I am therefore, writing this preface in case there should arise at some future time, enough interest for its publication. I have often described the years as the happiest in my scientific life. Those were the years when I was immersed in my investigations on radiative transfer and in the theory of stellar atmospheres: the years which culminated with the publication of my Radiative Transfer and which included my exact solution of Rayleigh s problem of the illumination and the polarization of the sunlit sky and the unraveling of the continuous absorption coefficient of H and the continuous spectrum of the sun and the stars. xiii

14 xiv A Scientific Autobiography: S. Chandrasekhar Half way during this period of intense and joyous activity, in September 1947, we went on a brief vacation to East Orleans, Cape Cod, at the invitation of Rupert Wildt. And while at Cape Cod, Lalitha repeated her suggestion of some months earlier that I write a history of my series of papers on The Radiative Equilibrium of a Stellar Atmosphere. Her suggestion arose from her having observed my total involvement in what I was then doing. Before I left for Cape Cod, Paper XXI of the series had been sent to press, the end of the series (Paper XXIV was the last) was in sight, and the prospect of starting on my book was imminent. It was thus, in Cape Cod, in September 1947, that a preliminary draft of the first instalment was written; it was completed two years later when the manuscript of my Radiative Transfer was sent to press in September The second instalment was written in 1960 on the completion of my Hydrodynamic and Hydromagnetic Stability. And the last of them was written just about a year ago on the completion of my last book on The Mathematical Theory of Black Holes. The various instalments describe in detail the evolution of my scientific work during the past forty years and records each investigation, describing the doubts and the successes, the trials and the tribulations. And the parts my various associates and assistants played in the completion of the different investigations are detailed. But Lalitha, only rarely mentioned, was always

15 Preface xv present, always supportive, and always encouraging. And this is the place to record the depth of my indebtedness to her. But the full measure of it cannot really be recorded: it is too deep and too all pervasive. Let me then record very simply that Lalitha has been the principal motivating force and strength of my life. Her support has been constant, unwavering, and sustained. And it has been my mainstay during times of stress and discouragement. Thus, during the last months of 1981 when my last book was nearing completion, one snag after another kept on springing. Each had to be resolved patiently; but time was running short very short. One such snag was particularly intractable. Lalitha identified herself so completely with my efforts that she said there is pal hanging over everything; when will it lift. That is typical of her involvement in my work and of the way she has shared in my life: selfless, devoted, and ever patient and waiting. And so, I dedicate this autobiography, which is indeed my life, to her. S. Chandrasekhar January 22, 1983

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17 Contents Dedication Foreword by Kameshwar C. Wali Preface by S. Chandrasekhar I. A History of My Papers on Radiative Equilibrium ( ) II. Turbulence; Hydromagnetism ( ) 21 III. The Development of the Virial Method and Ellipsoidal Figures of Equilibrium ( ) IV. General Relativity ( ) 75 V. The Fallow Period ( ) 91 VI. General Relativity; Ryerson Lecture; Separation of Dirac Equation (January 1975 August 1977) VII. General Relativity; Kerr Newman Perturbations (August 1977 December 1978) v vii xiii VIII A Year of Failures and of Obligations 139 IX. 1980, 1981: The Mathematical Theory of Black Holes 151 xvii

18 xviii Contents X. POSTSCRIPT: 1982, a Year that Passed 185 XI. The Beginning of the End ( ) 187 XII. Continued Efforts I (September 1985 May 1987) 199 XIII. Continued Efforts II (May 1987 September 1989) 213 XIV. Continued Efforts III (September 1989 October 1991) 231 XV. Continued Efforts IV(November 1991 December 1994) 251 Notes & Comments by Kameshwar C. Wali 259