From ysrao@csre.iitb.ernet.in Thu Oct 12 22:00:15 2000 Date: Thu, 12 Oct 2000 21:59:51 +0530 (IST) From: Dr.Y.S. Rao To: discuss-faculty@cc.iitb.ernet.in Subject: Chandrasekhar Prof. A.K. Pani's forwarded email on Nobel laureate Subrahmanyan Chandrasekhar prompted me to write this lengthy email. Both Chadrasekhar's and his uncle Sir C.V. Raman's lives inspire every one. They were full and productive till their last days. I attended Chandrasekhar's lecture in TIFR and had the opportunity to talk to him a little when he was with Dr. Narlikar. I found a great attraction in him while he was giving a lecture on black holes. He talked to me with a kind smile which still inspires me. I have been using his radiative transfer equations for the calculation of earth radiation at microwave frequencies. So I decided to write you more interesting things on his life and his work to complement Prof. Pani's email. After reaching highest goal and thinking what is going on at millions of light years away, where even light could not escape, he left to us some questions which are interesting to every one. After he left this world, what has remained with us is "Chandrasekhar limit", like "Raman effect". These two will remain as long as Sun and Moon remain with us. Both C.V. Raman and Chandrasekhar studied in Presidency college, Madras. At the age of 18, they wrote research papers on their own. Chandrasekhar's next paper, written immediately after graduation, became the basis for his Nobel prize. Most of the work on this paper was done during his long voyage from Mumbai to London in August 1930. C.V. Raman was a great experimental physicist and Chandrasekhar was a great genius in theoretical physics, astrophysics and mathematics. His uncle C.V. Raman did not acknowledge any one in his first paper as he did not take any kind of help. After passing Civil Service Examination, C.V. Raman joined as an Assistant Accountant-General in Calcutta in June 1907. While working in Indian Finance Department, he contributed 30 original research publications in very good journals in 10 years (1907-1917). He used his extra time and worked in a dusty old building at 210 Bow Bazar street of Calcutta under the most adverse circumstances amidst the distraction of pressing official duties. Later, he resigned from his lucrative official appointment and joined as a professor with the influence of Sir Asutosh Mukerjee. While travelling to Europe by ship, his attention was drawn to the origin of blue colour of the Mediterranean sea that led to his Nobel prize. When Raman received his Nobel prize in 1930, his nephew Chandrasekhar wrote a historic paper in the same year that led to another Nobel prize in 1983 for an Indian born scientist. The reasons for 50 years delay for Nebel prize was lack of understanding of his complicated work and controversies in accepting his theory. One lady asked Chandrasekhar "The work that has been recognised was done some fifty years ago. What have you been doing since?". He responded, "They also serve who stand and wait." For which she asked, "Have you been waiting for the Nobel Prize all these years?". His answer was, "There was no Nobel Prize in Milton's time!". He did not give much importance for his Nobel Prize. He mentioned in a letter to his brother "The award, while gratifying, is not the one that I sought, or indeed one that I considered relevant to a scientific career." Stars, like Sun, maintain their equilibrium during their active period by balancing the inward gravitational attraction of their mass against their outward pressure, which is a consequence of nuclear fusion reactions taking place in their interior. In this way hydrogen content of the star is 'burnt' to form more stable helium nuclei and release the energy that is eventually radiated as starlight. What happens when the 'fuel' of the hydrogen is exhausted, that is, all of it has been made into helium? Since there is no outward pressure, the star collapses as a result of the gravitational forces. Chandrasekhar observed that if the mass of the star is large, correspondingly the electrons in the collapsed state will move faster and when their speed increases eventually to nearly the speed of light, the analysis becomes a little different. In particular, the pressure does not increase enough to keep pace with the increase of gravitational attraction. Consequently no stable object is formed and the star proceeds towards a more compact object. A stage will be reached when the gravity of such an object is so strong that nothing - not even light - escapes from it. A very massive star, after exhausting its nuclear fuel, ends up as a black hole in the universe. His great work was rejected by Royal Astronomical Society due to U.Ks arrogant world renowned Scientist Sir Arthur Eddington who is famous for the calculation of Sun's interior temperature. So, Chandrasekhar sent his paper entitled "The maximum mass of ideal white dwarfs" to Astrophysical. Journal., U.S. and it was published in March 1931 with great difficulty. Later, Chandrasekhar was invited to the Royal Astronomical Society in 1935 to present his work. After his presentation, his hero Eddington stood up and ridiculed his paper without warning and said "The star has to go on radiating and radiating and contracting and contracting until, I suppose, it gets to a few kilometers radius, when gravity becomes strong enough to hold the radiation and the star can at last have peace." In contracting stage, one ton of mass can go into a small match box. Chadrasekhar was upset, humiliated, disappointed and was unable to explain. All this insult came during International conference. Other great scientists Ralph H. Fowler, Niels Bohr and Paul Dirac found Chandrasekhar's calculations sound. Eddington was unconvinced. The episode, Chandrasekhar said later, "forced me to carefully consider my reasons for wanting to continue to do Astrophysics in the face of such a painful experience." Nevertheless he nursed no rancour and was gracious enough to address Eddington as "the most distinguished astrophysicist of his time", when he gave two lectures to mark his birth centenary. Eddington nominated Chandrasekhar as the Fellow of the Royal Society in 1944. When Chandrasekhar took U.S. Citizenship, his father felt that he had betrayed his birthplace. But he remained loyal to his Indian ways, his vegetarianism and deep concern for India's future. Dr. Ramachandran, particle physicist, and Director of the Institute of Mathematical Sciences, Madras was Chandrasekhar's student at the University of Chicago in the early 1960's as a Ph.D. Scholar. He narrates "I had the privilege of attending Prof. Chandrasekhar's course on the General Theory of Relativity. He started the first lecture by confessing that he was planning to learn General Relativity by offering this course. Teaching is indeed the best way to learn anything, and in the process of preparing for lectures there is an opportunity to organise one's thoughts and explore the subtleties of the subject that one may miss otherwise. Chadrasekhar's lectures were always well prepared and delivered without any fanfare and with extensive and explicit derivations covering all the available space on the blackboards in the Rayerson lecture theatre. It was never flamboyant or dramatic and always so even-paced that it was easy to take notes. I find that the notes I took then can easily form the foundation for an introductory course on General Relativity even today." Chandrasekhar took up a new area of study every about ten years. Published prolifiacally in the subject over the decade and then published a treatise as a last word in the subject. So in his lifespan he had made a clean sweep of something like half a dozen subjects. He was a great Physicist of the twentieth century, one of those to put India on the world map of Physics. He was a workholic and put in long hours in systematic study. One weekend, when the entire Physics Department of University of Chicago; graduate students, faculty, secretaries and all-, went on a picnic to the lakeside campus in Williams Bay, Chandrasekhar was seen quietly working in his office; totally oblivious of the fun and frolic so close by. Chandrasekhar disapproved of the casualness that prevailed in American classrooms. Smoking in the classroom, drinking beverages and walking in and out of the lecture hall after the lecture had begun were all unthinkable for him. He conveyed the message firmly. He would start with a plea that his throat got irritated and speech impeded by the smoke and that would rather no one smoked in the class. Since he easily lost track of his thoughts, doors may not be opened once the lecture began. Interruptions were not welcome. In spite of Chandrasekhar's voluminous achievements, he was a simple and modest person. His colleague John A. Simpson, a distinguished professor, narrates an incident: "I saw him walking down the hall looking sad. I asked him what was wrong. He said ' I just turned in my annual report to the Director and I wrote only five papers this year'. He was concerned that he had slowed down at a time when most others would have completely quite active professional carrier. I reminded him: "Didn't you also write a book on black holes this year?' 'Oh,' he brightened considerably, ' I forgot about that'." Despite the Nobel Prize and the numerous honours conferred on him - Fellow of the Royal Society, the Copley Medal, Padma Vibhusahn and scores of honorary doctorates, Chandra still said, "The hope for contentment and a peaceful outlook on life as a result of pursuing a goal has remained unfulfilled. It is not clear whether the single-minded pursuit of science at the expense of other personal aspects of life is justifiable..... (A fulfilled) life is not necessarily one in which you pursue certain goals, there must be other things." Elsewhere he remarked: "The pursuit of science has often been compared with 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?.... But there is nothing mean or lowly in standing in the valley below and awaiting the sunrise over the Kanchanjunga." Chandrasekhar will remain an inspiration for all those committed to seeking knowledge, whether they scale the Everest or are content to experience the beauty from "the valley." thank you, -y.s.rao- Books about Chandrasekhar (First 2 books are worth to read) ------------------------- 1) A Biography of S. Chandrasekhar, New Delhi, Penguim Books, 1992 2) S. Chandrasekhar : the man behind the legend, edited by Kameshwar C. Wali, Imperial college press, 1997. 3) White Dwarves to Black Holes: The Legacy of S. Chandrasekhar, edited by G. Srinivasan, University of Chicago press, 1999. Books by Chandra: ------------------ 1) Introduction to the Study of Stellar Structure, 1939. 2) Principles of Stellar Dynamics, 1943. 3) Radiative Transfer, 1950. 4) Hydrodynamic and Hydromagnetic Stability, 1961. 5) The Mathematical Theory of Black Holes, 1983. 6) Eddington: The Most Distinguished Astrophysicist of His Time, 1983. 7) Truth and Beauty, 1987. 8) Newtons Principia for the Common Reader, 1995. No. of Ph.Ds received under his guidance: 51