Subrahmanyan Chandrasekhar

Subrahmanyan Chandrasekhar FRS [1] (/ˌtʃʌndrəˈseɪkər/ (listen); 19 October 1910 – 21 August 1995)[3] was an Indian American astrophysicist who spent his professional life in the United States.[4] He was awarded the 1983 Nobel Prize for Physics with William A. Fowler for "...theoretical studies of the physical processes of importance to the structure and evolution of the stars". His mathematical treatment of stellar evolution yielded many of the current theoretical models of the later evolutionary stages of massive stars and black holes.[5][6] The Chandrasekhar limit is named after him.

Chandrasekhar worked on a wide variety of physical problems in his lifetime, contributing to the contemporary understanding of stellar structure, white dwarfs, stellar dynamics, stochastic process, radiative transfer, the quantum theory of the hydrogen anion, hydrodynamic and hydromagnetic stability, turbulence, equilibrium and the stability of ellipsoidal figures of equilibrium, general relativity, mathematical theory of black holes and theory of colliding gravitational waves.[7] At the University of Cambridge, he developed a theoretical model explaining the structure of white dwarf stars that took into account the relativistic variation of mass with the velocities of electrons that comprise their degenerate matter. He showed that the mass of a white dwarf could not exceed 1.44 times that of the Sun – the Chandrasekhar limit. Chandrasekhar revised the models of stellar dynamics first outlined by Jan Oort and others by considering the effects of fluctuating gravitational fields within the Milky Way on stars rotating about the galactic centre. His solution to this complex dynamical problem involved a set of twenty partial differential equations, describing a new quantity he termed 'dynamical friction', which has the dual effects of decelerating the star and helping to stabilize clusters of stars. Chandrasekhar extended this analysis to the interstellar medium, showing that clouds of galactic gas and dust are distributed very unevenly.

Chandrasekhar studied at Presidency College, Madras (now Chennai) and the University of Cambridge. A long-time professor at the University of Chicago, he did some of his studies at the Yerkes Observatory, and served as editor of The Astrophysical Journal from 1952 to 1971. He was on the faculty at Chicago from 1937 until his death in 1995 at the age of 84, and was the Morton D. Hull Distinguished Service Professor of Theoretical Astrophysics.[8]

Subrahmanyan Chandrasekhar

Subrahmanyan Chandrasekhar
Subrahmanyan Chandrasekhar
Born19 October 1910
Died21 August 1995 (aged 84)
ResidenceIndia, United States
NationalityIndian, American
Alma mater
Known for
Awards
Scientific career
FieldsAstrophysics
General Relativity
Fluid dynamics
Radiation
InstitutionsUniversity of Chicago
Yerkes Observatory
Ballistic Research Laboratory
University of Cambridge
ThesisPolytropic distributions (1933)
Doctoral advisorRalph H. Fowler
Arthur Eddington
Doctoral students
Signature
Subrahmanyan Chandrasekhar signature

Early life and education

Chandrasekhar was born on 19 October 1910 in Lahore, Punjab, British India (now Pakistan) in a Tamil Hindu family,[9] to Sitalakshmi (Divan Bahadur) Balakrishnan (1891–1931) and Chandrasekhara Subrahmanya Ayyar (1885–1960)[10] who was stationed in Lahore as Deputy Auditor General of the Northwestern Railways at the time of Chandrasekhar's birth. He had two elder sisters, Rajalakshmi and Balaparvathi, three younger brothers, Vishwanathan, Balakrishnan, and Ramanathan and four younger sisters, Sarada, Vidya, Savitri, and Sundari. His paternal uncle was the Indian physicist and Nobel laureate C. V. Raman. His mother was devoted to intellectual pursuits, had translated Henrik Ibsen's A Doll's House into Tamil and is credited with arousing Chandra's intellectual curiosity at an early age.[11] The family moved from Lahore to Allahabad in 1916, and finally settled in Madras in 1918.

Chandrasekhar was tutored at home until the age of 12.[11] In middle school his father would teach him Mathematics and Physics and his mother would teach him Tamil. He later attended the Hindu High School, Triplicane, Madras during the years 1922–25. Subsequently, he studied at Presidency College, Madras from 1925 to 1930, writing his first paper, "The Compton Scattering and the New Statistics", in 1929 after being inspired by a lecture by Arnold Sommerfeld.[12] He obtained his bachelor's degree, B.Sc. (Hon.), in physics, in June 1930. In July 1930, Chandrasekhar was awarded a Government of India scholarship to pursue graduate studies at the University of Cambridge, where he was admitted to Trinity College, Cambridge, secured by R. H. Fowler with whom he communicated his first paper. During his travels to England, Chandrasekhar spent his time working out the statistical mechanics of the degenerate electron gas in white dwarf stars, providing relativistic corrections to Fowler's previous work (see Legacy below).

At Cambridge University

In his first year at Cambridge, as a research student of Fowler, Chandrasekhar spent his time calculating mean opacities and applying his results to the construction of an improved model for the limiting mass of the degenerate star. At the meetings of the Royal Astronomical Society, he met E. A. Milne. At the invitation of Max Born he spent the summer of 1931, his second year of post-graduate studies, at Born's institute at Göttingen, working on opacities, atomic absorption coefficients, and model stellar photospheres. On the advice of P. A. M. Dirac, he spent his final year of graduate studies at the Institute for Theoretical Physics in Copenhagen, where he met Niels Bohr.

After receiving a bronze medal for his work on degenerate stars, in the summer of 1933, Chandrasekhar was awarded his PhD degree at Cambridge with a thesis among his four papers on rotating self-gravitating polytropes. On 9 October, he was elected to a Prize Fellowship at Trinity College for the period 1933–1937, becoming only the second Indian to receive a Trinity Fellowship after Srinivasa Ramanujan 16 years earlier. He had been so certain of failing to obtain the fellowship that he had already made arrangements to study under Milne that autumn at Oxford, even going to the extent of renting a flat there.[12]

During this time, Chandrasekhar became acquainted with British physicist Sir Arthur Eddington. In an infamous encounter at the Royal Astronomical Society in London in 1935, Eddington publicly ridiculed the concept of the Chandrasekhar limit.[11] Although Eddington would later be proved wrong by computers and the first positive identification of a black hole in 1972, this encounter caused Chandrasekhar to contemplate employment outside the UK. Later in life, on multiple occasions, Chandrasekhar expressed the view that Eddington's behavior was in part racially motivated.[13]

Career and research

Early career

In 1935, Chandrasekhar was invited by the Director of the Harvard Observatory, Harlow Shapley, to be a visiting lecturer in theoretical astrophysics for a three-month period. He travelled to the United States in December. During his visit to Harvard, Chandrasekhar greatly impressed Shapley, but declined his offer of a Harvard research fellowship. At the same time, Chandrasekhar met Gerald Kuiper, a noted Dutch astrophysical observationalist who was then a leading authority on white dwarfs. Kuiper had recently been recruited by Otto Struve, the Director of the Yerkes Observatory in Williams Bay, Wisconsin, which was run by the University of Chicago, and the university's President Robert Maynard Hutchins. Having known of Chandrasekhar, Struve was then considering him for one of three faculty posts in astrophysics, along with Kuiper; the other opening had been filled by Bengt Stromgren, a Danish theorist.[12] Following a praise-filled recommendation from Kuiper, Struve invited Chandrasekhar to Yerkes in March 1936 and offered him the job. Though Chandrasekhar was keenly interested, he initially declined the offer and left for England; after Hutchins sent a radiogram to Chandrasekhar during the voyage, he finally accepted, returning to Yerkes as an Assistant Professor of Theoretical Astrophysics in December 1936.[12]

Chandrasekhar remained at the University of Chicago for his entire career. He was promoted to associate professor in 1941 and to full professor two years later at just 33 years of age.[12] In 1952, he became Morton D. Hull Distinguished Service Professor of Theoretical Astrophysics. In 1953, he and his wife, Lalitha Chandrasekhar, took American citizenship.[14] Famously, Chandrasekhar declined many offers from other universities, including one to succeed Henry Norris Russell, the preeminent American astronomer, as director of the Princeton University Observatory.

After the Laboratory for Astrophysics and Space Research (LASR) was built by NASA in 1966 at the University, Chandrasekhar occupied one of the four corner offices on the second floor. (The other corners housed John A. Simpson, Peter Meyer, and Eugene N. Parker.) Chandrasekhar lived at 4800 Lake Shore Drive after the high-rise apartment complex was built in the late 1960s, and later at 5550 Dorchester Building.

World War II

During World War II, Chandrasekhar worked at the Ballistic Research Laboratory at the Aberdeen Proving Ground in Maryland. While there, he worked on problems of ballistics, resulting in reports such as 1943's On the decay of plane shock waves, Optimum height for the bursting of a 105mm shell, On the Conditions for the Existence of Three Shock Waves,[15] and The normal reflection of a blast wave.[16][7] Chandrasekhar's expertise in hydrodynamics led Robert Oppenheimer to invite him to join the Manhattan Project at Los Alamos, but delays in the processing of his security clearance prevented him from contributing to the project. It has been rumoured that he visited the Calutron project, where he suggested that young women be employed to operate the calutrons producing enriched radioactive materials for the atomic weapons.

Philosophy of systematization

He wrote that his scientific research was motivated by his desire to participate in the progress of different subjects in science to the best of his ability, and that the prime motive underlying his work was systematization. "What a scientist tries to do essentially is to select a certain domain, a certain aspect, or a certain detail, and see if that takes its appropriate place in a general scheme which has form and coherence; and, if not, to seek further information which would help him to do that." [17]

Chandrasekhar developed a unique style of mastering several fields of physics and astrophysics; consequently, his working life can be divided into distinct periods. He would exhaustively study a specific area, publish several papers in it and then write a book summarizing the major concepts in the field. He would then move on to another field for the next decade and repeat the pattern. Thus he studied stellar structure, including the theory of white dwarfs, during the years 1929 to 1939, and subsequently focused on stellar dynamics, theory of Brownian motion from 1939 to 1943. Next, he concentrated on the theory of radiative transfer and the quantum theory of the negative ion of hydrogen from 1943 to 1950. This was followed by sustained work on turbulence and hydrodynamic and hydromagnetic stability from 1950 to 1961. In the 1960s, he studied the equilibrium and the stability of ellipsoidal figures of equilibrium, and also general relativity. During the period, 1971 to 1983 he studied the mathematical theory of black holes, and, finally, during the late 80s, he worked on the theory of colliding gravitational waves.[7]

Work with students

Chandra worked closely with his students and expressed pride in the fact that over a 50-year period (from roughly 1930 to 1980), the average age of his co-author collaborators had remained the same, at around 30. He insisted that students address him as "Chandrasekhar" until they received their Ph.D. degree, after which time they (as other colleagues) were encouraged to address him as "Chandra". When Chandrasekhar was working at the Yerkes Observatory in 1940s, he would drive 150 miles (240 km) to and fro every weekend to teach a course at the University of Chicago. Two of the students who took the course, Tsung-Dao Lee and Chen-Ning Yang, won the Nobel prize before he could get one for himself. Regarding classroom interactions during his lectures, noted astrophysicist Carl Sagan stated from firsthand experience that "frivolous questions" from unprepared students were "dealt with in the manner of a summary execution", while questions of merit "were given serious attention and response".[4]

Other activities

From 1952 to 1971 Chandrasekhar was editor of The Astrophysical Journal.[18] When Eugene Parker submitted a paper on his discovery of solar wind in 1957, two eminent reviewers rejected the paper. However, since Chandra as an editor could not find any mathematical flaws in Parker's work, he went ahead and published the paper in 1958.[19]

During the years 1990 to 1995, Chandrasekhar worked on a project devoted to explaining the detailed geometric arguments in Sir Isaac Newton's Philosophiae Naturalis Principia Mathematica using the language and methods of ordinary calculus. The effort resulted in the book Newton's Principia for the Common Reader, published in 1995. Chandrasekhar was an honorary member of the International Academy of Science.

Personal life

Chandrasekhar married Lalitha Doraiswamy in September 1936. He had met her as a fellow student at Presidency College, Madras. Chandrasekhar was the nephew of C. V. Raman, who was awarded the Nobel Prize for Physics in 1930. He became a naturalized citizen of the U.S. in 1953. Many considered him as warm, positive, generous, unassuming, meticulous, and open to debate, while some others as private, intimidating, impatient and stubborn regarding non-scientific matters,[4] and unforgiving to those who ridiculed his work.[20]

Chandrasekhar died of a sudden heart attack at the University of Chicago Hospital in 1995, having survived a prior heart attack in 1975.[4] He was survived by his wife, Lalitha Chandrasekhar, who died on 2 September 2013 at the age of 102.[21] He was a serious student of literature and western classical music.[20]

Once when involved in a discussion about the Gita, Chandrasekhar said, "I should like to preface my remarks with a personal statement in order that my later remarks will not be misunderstood. I consider myself an atheist."[22] This was also confirmed many times in his other talks.[23] In an interview with Kevin Krisciunas at the University of Chicago, on 6 October 1987, Chandrasekhar commented: "Of course, he (Otto Struve) knew I was an atheist, and he never brought up the subject with me".[24]

Awards, honours and legacy

Nobel prize

Chandrasekhar was awarded the Nobel Prize in Physics in 1983 for his studies on the physical processes important to the structure and evolution of stars. Chandrasekhar accepted this honor, but was upset the citation mentioned only his earliest work, seeing it as a denigration of a lifetime's achievement. He shared it with William A. Fowler.

Other awards

Subrahmanyan Chandrasekhar Exhibition - Science City - Kolkata 2011-01-07 9514
An exhibition on life and works of Subrahmanyan Chandrasekhar was held at Science City, Kolkata, on January, 2011.

Legacy

Chandrasekhar's most notable work is on the astrophysical Chandrasekhar limit. The limit gives the maximum mass of a white dwarf star, ~1.44 solar masses, or equivalently, the minimum mass that must be exceeded for a star to collapse into a neutron star or black hole (following a supernova). The limit was first calculated by Chandrasekhar in 1930 during his maiden voyage from India to Cambridge, England for his graduate studies. In 1979, NASA named the third of its four "Great Observatories" after Chandrasekhar. This followed a naming contest which attracted 6,000 entries from fifty states and sixty-one countries. The Chandra X-ray Observatory was launched and deployed by Space Shuttle Columbia on 23 July 1999. The Chandrasekhar number, an important dimensionless number of magnetohydrodynamics, is named after him. The asteroid 1958 Chandra is also named after Chandrasekhar. The Himalayan Chandra Telescope is named after him. In the Biographical Memoirs of the Fellows of the Royal Society of London, R. J. Tayler wrote: "Chandrasekhar was a classical applied mathematician whose research was primarily applied in astronomy and whose like will probably never be seen again."[1]

Chandrasekhar guided 45 students to their PhDs.[31] After his death, his widow Lalitha Chandrasekhar made a gift of his Nobel Prize money to the University of Chicago towards the establishment of the Subrahmanyan Chandrasekhar Memorial Fellowship. First awarded in the year 2000, this fellowship is given annually to an outstanding applicant to graduate school in the PhD programs of the Department of Physics or the Department of Astronomy and Astrophysics.[32]

The Chandra Astrophysics Institute (CAI) is a program offered for high school students who are interested in astrophysics mentored by MIT scientists[33] and sponsored by the Chandra X-ray Observatory.[34] American astronomer Carl Sagan, who studied mathematics under Chandrasekhar at the University of Chicago, praised him in the book The Demon-Haunted World: "I discovered what true mathematical elegance is from Subrahmanyan Chandrasekhar." On 19 October 2017, Google showed a Google Doodle in 28 countries honouring Chandrasekhar's 107th birthday and the Chandrasekhar limit.[35][36]

In 2010, on account of Chandra's 100th birthday, University of Chicago conducted a symposium titled Chandrasekhar Centennial Symposium 2010 which was attended by leading astrophysicists such as Roger Penrose, Kip Thorne, Freeman Dyson, Jayant V. Narlikar, Rashid Sunyaev, G. Srinivasan, and Clifford Will. Its research talks were published in 2011 as a book titled Fluid flows to Black Holes: A tribute to S Chandrasekhar on his birth centenary.[37][38][39]

Publications

Books

  • Chandrasekhar, S. (1958) [1939]. An Introduction to the Study of Stellar Structure. New York: Dover. ISBN 978-0-486-60413-8.
  • Chandrasekhar, S. (2005) [1942]. Principles of Stellar Dynamics. New York: Dover. ISBN 978-0-486-44273-0.
  • Chandrasekhar, S. (1960) [1950]. Radiative Transfer. New York: Dover. ISBN 978-0-486-60590-6.
  • Chandrasekhar, S. (1975) [1960]. Plasma Physics. Chicago: The University of Chicago Press. ISBN 978-0-226-10084-5.
  • Chandrasekhar, S. (1981) [1961]. Hydrodynamic and Hydromagnetic Stability. New York: Dover. ISBN 978-0-486-64071-6.
  • Chandrasekhar, S. (1987) [1969]. Ellipsoidal Figures of Equilibrium. New York: Dover. ISBN 978-0-486-65258-0.
  • Chandrasekhar, S. (1998) [1983]. The Mathematical Theory of Black Holes. New York: Oxford University Press. ISBN 978-0-19-850370-5.
  • Chandrasekhar, S. (1983) [1983]. Eddington: The Most Distinguished Astrophysicist of His Time. Cambridge University Press. ISBN 9780521257466.
  • Chandrasekhar, S. (1990) [1987]. Truth and Beauty. Aesthetics and Motivations in Science. Chicago: The University of Chicago Press. ISBN 978-0-226-10087-6.
  • Chandrasekhar, S. (1995). Newton's Principia for the Common Reader. Oxford: Clarendon Press. ISBN 978-0-19-851744-3.
  • Spiegel, E.A. (2011) [1954]. The Theory of Turbulence : Subrahmanyan Chandrasekhar's 1954 Lectures. Netherlands: Springer. ISBN 978-94-007-0117-5.

Notes

  • Chandrasekhar, S. (1943). "Stochastic Problems in Physics and Astronomy". Reviews of Modern Physics. 15 (1): 1–89. Bibcode:1943RvMP...15....1C. doi:10.1103/RevModPhys.15.1.
  • Chandrasekhar, S. (1993). Classical general relativity. Royal Society.
  • Chandrasekhar, S. (1979). The Role of General Relativity: Retrospect and Prospect. Proc. IAU Meeting.[40]
  • Chandrasekhar, S. (1943). New methods in stellar dynamics. New York Academy of Sciences.
  • Chandrasekhar, S. (1954). The illumination and polarization of the sunlit sky on Rayleigh scattering. American Philosophical Society.
  • Chandrasekhar, S. (1983). On Stars, their evolution and their stability, Noble lecture. Stockholm: Noble Foundation.
  • Chandrasekhar, S. (1981). New horizons of human knowledge: a series of public talks given at Unesco. Unesco Press.
  • Chandrasekhar, S. (1975). Shakespeare, Newton, and Beethoven: Or, Patterns of Creativity. University of Chicago.
  • Chandrasekhar, S. (1973). P.A.M. Dirac on his seventieth birthday. Contemporary Physics.[41]
  • Chandrasekhar, S. (1947). Heywood, Robert B., ed. The Works of the Mind:The Scientist. Chicago: University of Chicago Press. pp. 159–179. OCLC 752682744.
  • Chandrasekhar, S. (1995). Reminiscences and discoveries on Ramanujan's bust. Royal Society. ASIN B001B12NJ8.
  • Chandrasekhar, S. (1990). How one may explore the physical content of the general theory of relativity. American Mathematical Society. ASIN B001B10QTM.

Journals

Chandrasekhar published around 380 papers[42][43] in his lifetime. He wrote his first paper in 1928 when he was still an undergraduate student about Compton effect[44] and last paper which was accepted for publication just two months before his death was in 1995 which was about non-radial oscillation of stars.[45] The University of Chicago Press published selected papers of Chandrasekhar in seven volumes.

  • Chandrasekhar, S. (1989). Selected Papers, Vol 1, Stellar structure and stellar atmospheres. Chicago: University of Chicago Press. ISBN 9780226100890.
  • Chandrasekhar, S. (1989). Selected Papers, Vol 2, Radiative transfer and negative ion of hydrogen. Chicago: University of Chicago Press. ISBN 9780226100920.
  • Chandrasekhar, S. (1989). Selected Papers, Vol 3, Stochastic, statistical and hydromagnetic problems in Physics and Astronomy. Chicago: University of Chicago Press. ISBN 9780226100944.
  • Chandrasekhar, S. (1989). Selected Papers, Vol 4, Plasma Physics, Hydrodynamic and Hydromagnetic stability, and applications of the Tensor-Virial theorem. Chicago: University of Chicago Press. ISBN 9780226100975.
  • Chandrasekhar, S. (1990). Selected Papers, Vol 5, Relativistic Astrophysics. Chicago: University of Chicago Press. ISBN 9780226100982.
  • Chandrasekhar, S. (1991). Selected Papers, Vol 6, The Mathematical Theory of Black Holes and of Colliding Plane Waves. Chicago: University of Chicago Press. ISBN 9780226101019.
  • Chandrasekhar, S. (1997). Selected Papers, Vol 7, The non-radial oscillations of star in General Relativity and other writings. Chicago: University of Chicago Press. ISBN 9780226101040.

Books and articles about Chandrasekhar

  • Miller, Arthur I. (2005). Empire of the Stars: Friendship, Obsession, and Betrayal in the Quest for Black Holes. Boston: Houghton Mifflin. ISBN 978-0-618-34151-1.
  • Srinivasan, G., ed. (1997). From White Dwarfs to Black Holes: The Legacy of S. Chandrasekhar. Chicago: The University of Chicago Press. ISBN 978-0-226-76996-7.
  • Penrose, Roger (1996). "Chandrasekhar, Black Holes and Singularities" (PDF). Journal of Astrophysics and Astronomy. 17 (3–4): 213–231. Bibcode:1996JApA...17..213P. CiteSeerX 10.1.1.496.2529. doi:10.1007/BF02702305.
  • Parker, E. (1996). "S. Chandrasekhar and Magnetohydrodynamics". Journal of Astrophysics and Astronomy. 17 (3–4): 147–166. Bibcode:1996JApA...17..147P. doi:10.1007/BF02702301.[46]
  • Wali, Kameshwar C. (1991). Chandra: A Biography of S. Chandrasekhar. Chicago: The University of Chicago Press. ISBN 978-0-226-87054-0.
  • Wali, Kameshwar C., ed. (1997). Chandrasekhar: The Man Behind the Legend - Chandra Remembered. London: imperial College Press. ISBN 978-1-86094-038-5.
  • Wignesan, T., ed. (2004). The Man who Dwarfed the Stars. The Asianists' Asia. ISSN 1298-0358.
  • Venkataraman, G. (1992). Chandrasekhar and His Limit. Hyderabad, India: Universities Press. ISBN 978-81-7371-035-3.
  • Sreenivasan, K. R. (2019). "Chandrasekhar's Fluid Dynamics". Annual Review of Fluid Mechanics. 51: 1–24. doi:10.1146/annurev-fluid-010518-040537.[47]
  • Saikia, D J.; et al., eds. (2011). Fluid flows to Black Holes: A tribute to S Chandrasekhar on his birth centenary. Singapore: World Scientific Publishing Co. Ptd Ltd. ISBN 978-981-4299-57-2.
  • Kameshwar, C Wali, ed. (2001). A Quest For Perspectives. Singapore: World Scientific Publishing Co. Ptd Ltd. ISBN 978-1-86094-201-3.
  • Ramnath, Radhika, ed. (2012). S. Chandrasekhar: Man of Science. Harpercollins. ASIN B00C3EWIME.
  • Alic, Kameshwar C (2011). Kameshwar, C Wali, ed. A Scientific Autobiography: S Chandrasekhar. A Scientific Autobiography: S Chandrasekhar. Edited by K C Wali. Published by World Scientific Publishing Co. Pte. Ltd. Bibcode:2010sasc.book.....W. doi:10.1142/7686. ISBN 978-981-4299-57-2.
  • Salwi, Dilip, ed. (2004). S. Chandrasekhar: The scholar scientist. Rupa. ISBN 978-8129104915.
  • Pandey, Rakesh Kumar, ed. (2017). Chandrasekhar Limit: Size of White Dwarfs. Lap Lambert Academic Publishing. ISBN 978-3330317666.

References

  1. ^ a b c d Tayler, R. J. (1996). "Subrahmanyan Chandrasekhar. 19 October 1910 – 21 August 1995". Biographical Memoirs of Fellows of the Royal Society. 42: 80–94. doi:10.1098/rsbm.1996.0006.
  2. ^ "Subrahmanyan Chandrasekhar – The Mathematics Genealogy Project". www.genealogy.math.ndsu.nodak.edu.
  3. ^ Osterbrock, Donald E. (December 1998). "Subrahmanyan Chandrasekhar (19 October 1910-21 August 1995)". Proceedings of the American Philosophical Society. American Philosophical Society. 142 (4): 658–665. ISSN 0003-049X. JSTOR 3152289. (Registration or subscription required)
  4. ^ a b c d C.), Wali, K. C. (Kameshwar (1991). Chandra : a biography of S. Chandrasekhar. Chicago: University of Chicago Press. p. 9. ISBN 978-0226870540. OCLC 21297960.
  5. ^ Vishveshwara, C.V. (25 April 2000). "Leaves from an unwritten diary: S. Chandrasekhar, Reminiscences and Reflections" (PDF). Current Science. 78 (8): 1025–1033. Retrieved 2008-02-27.
  6. ^ Horgan, J. (1994). "Profile: Subrahmanyan Chandrasekhar—Confronting the Final Limit". Scientific American. 270 (3): 32–33. doi:10.1038/scientificamerican0394-32.
  7. ^ a b c O'Connor, J. J.; Robertson, E. F. "Subrahmanyan Chandrasekhar". Biographies. School of Mathematics and Statistics University of St Andrews, Scotland. Retrieved 21 May 2012.
  8. ^ "Subrahmanyan Chandrasekhar". starchild.gsfc.nasa.gov. Retrieved 2017-10-19.
  9. ^ "Who was S Chandrasekhar?". The Indian Express. 2017-10-19. Retrieved 2019-01-13.
  10. ^ Chandrasekhar, S. 1983. Autobiography Nobel Foundation, Stockholm, Sweden.
  11. ^ a b c "S Chandrasekhar: Why Google honours him". www.aljazeera.com. Retrieved 2017-10-18.
  12. ^ a b c d e Trehan, Surindar Kumar (1995). "Subrahmanyan Chandrasekhar 1910-1995" (PDF). Biographical Memoirs of Fellows of the Indian National Science Academy. 23: 101–119.
  13. ^ K.C. Wali, "Chandrasekhar vs. Eddington: An Unanticipated Confrontation", Physics Today, vol. 35, no. 10, pp. 33–40 (October, 1982)
  14. ^ "S Chandrashekhar, India's great astrophysicist: Why Google Doodle is celebrating the Nobel prize winner". The Financial Express. 2017-10-19. Retrieved 2017-10-19.
  15. ^ Chandrasekhar, S. (1943). On the conditions for the existence of three shock waves. Ballistic Research Laboratory, Aberdeen Proving Ground, Report, (367).
  16. ^ Chandrasekhar, S. (1943). Optimum Height for the Bursting of a 105mm Shell (No. BRL-MR-139). Army Ballistic Research Lab Aberdeen Procing Ground MD. http://www.dtic.mil/dtic/tr/fulltext/u2/492801.pdf
  17. ^ The Works of the Mind, p.176, edited by Robert B. Heywood, University of Chicago Press, 1947.
  18. ^ Helmut A. Abt (1 December 1995). "Obituary – Chandrasekhar, Subrahmanyan". Astrophysical Journal. 454: 551. Bibcode:1995ApJ...454..551A. doi:10.1086/176507.
  19. ^ Parker, E. N. (1958). Dynamics of the interplanetary gas and magnetic fields. The Astrophysical Journal, 128, 664.
  20. ^ a b S. Chandrasekhar : the man behind the legend. Wali, K. C. (Kameshwar C.). London: Imperial College Press. 1997. p. 107. ISBN 978-1860940385. OCLC 38847561.
  21. ^ "Nobel laureate's wife Lalitha Chandrasekhar dies at 102". The Hindu. 2013-09-07. Retrieved 2014-01-02.
  22. ^ S. Chandrasekhar: the man behind the legend, Kameshwar C. Wali. Imperial College Press (1 January 1997) ISBN 978-1860940385
  23. ^ Kameshwar C. Wali (1991). Chandra: A Biography of Chandrasekhar. University of Chicago Press. p. 304. ISBN 9780226870557. SC: I am not religious in any sense; in fact, I consider myself an atheist.
  24. ^ "Interview with Dr. S. Chandrasekhar". American Institute of Physics.
  25. ^ "Grants, Prizes and Awards". American Astronomical Society. Archived from the original on 24 January 2010. Retrieved 24 February 2011.
  26. ^ "Past Winners of the Catherine Wolfe Bruce Gold Medal". Astronomical Society of the Pacific. Retrieved 24 February 2011.
  27. ^ "Winners of the Gold Medal of the Royal Astronomical Society". Royal Astronomical Society. Archived from the original on 25 May 2011. Retrieved 24 February 2011.
  28. ^ "Past Recipients of the Rumford Prize". American Academy of Arts and Sciences. Retrieved 24 February 2011.
  29. ^ "The President's National Medal of Science: Recipient Details – NSF – National Science Foundation". www.nsf.gov.
  30. ^ "Henry Draper Medal". National Academy of Sciences. Archived from the original on 26 January 2013. Retrieved 24 February 2011.
  31. ^ Singh, Virendra (26 October 2011). "S Chandrasekhar: His Life and Science". Resonance. 16 (10): 960. doi:10.1007/s12045-011-0094-0.
  32. ^ "Subrahmanyan Chandrasekhar Memorial Fellowship".
  33. ^ Hartman, Mark; Ashton, Peter; Porro, Irene; Ahmed, Shakib; Kol, Simba. "Chandra Astrophysics Institute". MIT OpenCourseWare. Retrieved 2017-10-20.
  34. ^ "The Chandra Astrophysics Institute – ChandraBlog – Fresh Chandra News". chandra.harvard.edu.
  35. ^ "S. Chandrasekhar's 107th Birthday".
  36. ^ Rajamanickam Antonimuthu (18 October 2017). "S. Chandrasekhar Google Doodle" – via YouTube.
  37. ^ "KPTC Event Video - Colloquia". kersten.uchicago.edu. Retrieved 2019-01-13.
  38. ^ "The 100th anniversary of the birth of Subrahmanyan Chandrasekhar: Chandrasekhar Centennial Symposium 2010 - Chicago - VideoLectures - VideoLectures.NET". videolectures.net. Retrieved 2019-01-13.
  39. ^ "NSF Award Search: Award#1039863 - Chandrasekhar Centennial Symposium; Chicago, IL; October 16-17, 2010". www.nsf.gov. Retrieved 2019-01-13.
  40. ^ Chandrasekhar, S (1980). "The role of general relativity in astronomy - Retrospect and prospect". Highlights of Astronomy. 5: 45–61. Bibcode:1980HiA.....5...45C. doi:10.1017/S1539299600003749.
  41. ^ Chandrasekhar, S. (1973). PAM dirac on his seventieth birthday. Contemporary Physics, 14(4), 389–394.
  42. ^ "Publications by S. Chandrasekhar" (PDF). Indian Academy of Sciences. Retrieved 15 May 2017.
  43. ^ Tayler, R. J. (1996). Subrahmanyan Chandrasekhar. 19 October 1910–21 August 1995. Biographical Memoirs of Fellows of the Royal Society, 42, 81–94.
  44. ^ "Thermodynamics of the Compton Effect with Reference to the Interior of the Stars" (PDF). Indian Journal of Physics. 3: 241–50.
  45. ^ Chandrasekhar, Subrahmanyan; Ferrari, Valeria (1995-08-08). "On the Non-Radial Oscillations of a Star: V. A Fully Relativistic Treatment of a Newtonian Star". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. The Royal Society. 450 (1939): 463–475. doi:10.1098/rspa.1995.0094. ISSN 1364-5021.
  46. ^ Parker, E. N (1996). "S. Chandrasekhar and Magnetohydrodynamics". Journal of Astrophysics and Astronomy. 17 (3–4): 147–166. Bibcode:1996JApA...17..147P. doi:10.1007/BF02702301.
  47. ^ Sreenivasan, K. R. (2019). "Chandrasekhar's Fluid Dynamics". Annual Review of Fluid Mechanics. 51: 1–24. doi:10.1146/annurev-fluid-010518-040537.

External links

Obituaries
1958 Chandra

1958 Chandra, provisional designation 1970 SB, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 35 kilometers in diameter.

It was discovered on 24 September 1970, by Argentinian astronomer Carlos Cesco at the Yale–Columbia Southern Station of the Leoncito Astronomical Complex in San Juan, Argentina (also see Félix Aguilar Observatory). It was named after astrophysicist Subrahmanyan Chandrasekhar.

Basilis C. Xanthopoulos

Basilis C. Xanthopoulos (also Vasilis; Greek: Βασίλης Κ. Ξανθόπουλος; 1951 – 27 November 1990) was a Greek theoretical physicist, well known in the field of general relativity for his contributions to the study of colliding plane waves.

Basilis Xanthopoulos was born in Drama, in 1951. After majoring in mathematics at the University of Thessaloniki he moved to the University of Chicago, where he earned his Ph.D. in 1978. During this time, he collaborated with Subrahmanyan Chandrasekhar on colliding plane waves. In particular, they discovered an exact solution which models two gravitational plane waves which collide, interact nonlinearly, and create in the interaction zone a curved region of spacetime which is locally isometric to the Kerr vacuum. This is now called the 'Chandrasekhar–Xanthopoulos colliding plane wave model.'

Xanthopoulos and his colleague Stephanos Pnevmatikos were murdered by a 32-year-old disgruntled post-graduate student, named Giorgos Petrodaskalakis (who later committed suicide), on the evening of 27 November 1990 at the University of Crete.

Chandra X-ray Observatory

The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space observatory launched on STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enabled by the high angular resolution of its mirrors. Since the Earth's atmosphere absorbs the vast majority of X-rays, they are not detectable from Earth-based telescopes; therefore space-based telescopes are required to make these observations. Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing as of 2019.

Chandra is one of the Great Observatories, along with the Hubble Space Telescope, Compton Gamma Ray Observatory (1991–2000), and the Spitzer Space Telescope. The telescope is named after the Nobel Prize-winning Indian-American astrophysicist Subrahmanyan Chandrasekhar. Its mission is similar to that of ESA's XMM-Newton spacecraft, also launched in 1999.

Chandrasekhar's variational principle

In astrophysics, Chandrasekhar's variational principle provides the stability criterion for a static barotropic star, subjected to radial perturbation, named after the Indian American astrophysicist Subrahmanyan Chandrasekhar.

Chandrasekhar's white dwarf equation

In astrophysics, Chandrasekhar's white dwarf equation is an initial value ordinary differential equation introduced by the Indian American astrophysicist Subrahmanyan Chandrasekhar, in his study of the gravitational potential of completely degenerate white dwarf stars. The equation reads as

with initial conditions

where measures the density of white dwarf, is the non-dimensional radial distance from the center and is a constant which is related to the density of the white dwarf at the center. When , this equation reduces to Lane–Emden equation with polytropic index . In the Lane-Emden equation, the density at the centre can be scaled out of the equation, but for white-dwarfs, the central density is directly tied to the equation.

Chandrasekhar family

The Chandrasekhar family is a distinguished Indian intellectual family, several of whose members achieved eminence, notably in the field of physics. Two members of the family, Sir C. V. Raman and his nephew, Subrahmanyan Chandrasekhar, were Nobel laureates in physics.

Chandrasekhar limit

The Chandrasekhar limit () is the maximum mass of a stable white dwarf star. The currently accepted value of the Chandrasekhar limit is about 1.4 M☉ (2.765×1030 kg).White dwarfs resist gravitational collapse primarily through electron degeneracy pressure (compare main sequence stars, which resist collapse through thermal pressure). The Chandrasekhar limit is the mass above which electron degeneracy pressure in the star's core is insufficient to balance the star's own gravitational self-attraction. Consequently, a white dwarf with a mass greater than the limit is subject to further gravitational collapse, evolving into a different type of stellar remnant, such as a neutron star or black hole. Those with masses under the limit remain stable as white dwarfs.The limit was named after Subrahmanyan Chandrasekhar, the Indian astrophysicist who improved upon the accuracy of the calculation in 1930, at the age of 20, in India by calculating the limit for a polytrope model of a star in hydrostatic equilibrium, and comparing his limit to the earlier limit found by E. C. Stoner for a uniform density star. Importantly, the existence of a limit, based on the conceptual breakthrough of combining relativity with Fermi degeneracy, was indeed first established in separate papers published by Wilhelm Anderson and E. C. Stoner in 1929. The limit was initially ignored by the community of scientists because such a limit would logically require the existence of black holes, which were considered a scientific impossibility at the time. That the roles of Stoner and Anderson are often forgotten in the astronomy community has been noted.

Chandrasekhar number

The Chandrasekhar number is a dimensionless quantity used in magnetic convection to represent ratio of the Lorentz force to the viscosity. It is named after the Indian astrophysicist Subrahmanyan Chandrasekhar.

The number's main function is as a measure of the magnetic field, being proportional to the square of a characteristic magnetic field in a system.

Chandrasekhar polarization

Chandrasekhar Polarization is a partial polarization of emergent radiation at the limb of rapidly rotating early-type stars or binary star system with purely electron-scattering atmosphere, named after the Indian American astrophysicist Subrahmanyan Chandrasekhar, who first predicted its existence theoretically in 1946.Chandrasekhar published series of 26 papers in The Astrophysical Journal titled On the Radiative Equilibrium of a Stellar Atmosphere from 1944 to 1948. In the 10th paper, he predicted that the purely electron stellar atmosphere emits a polarized light using Thomson law of scattering. The theory predicted that 11 percent polarization could be observed at maximum. But when this is applied to a spherical star, the net polarization effect was found to be zero, because of the spherical symmetry. But it took another 20 years to explain under what conditions this polarization can be observed. J. Patrick Harrington and George W. Collins, II showed that this symmetry is broken if we consider a rapidly rotating star (or a binary star system), in which the star is not exactly spherical, but slightly oblate due to extreme rotation (or tidal distortion in the case of binary system). The symmetry is also broken in eclipsing binary star system.

Chidambara Chandrasekaran

Chidambara Chandrasekaran (1911–2000) was noted Indian demographer and statistician, was educated in India, UK and the US. He graduated from Morris College, Nagpur, with a B.Sc. degree, followed by a M.Sc. degree from the Nagpur University, and a PhD degree in Statistics from University College London in 1938. He was also awarded an MPH degree from Johns Hopkins School of Hygiene and Public Health in 1947.

Note that in some publications his name is spelled as "Chandra Sekar".

He was related to two Nobel Prize winners: C. V. Raman was his uncle and Subrahmanyan Chandrasekhar was his cousin.

Dynamical friction

In astrophysics, dynamical friction or Chandrasekhar friction, sometimes called gravitational drag, is loss of momentum and kinetic energy of moving bodies through gravitational interactions with surrounding matter in space. It was first discussed in detail by Subrahmanyan Chandrasekhar in 1943.

Emden–Chandrasekhar equation

In astrophysics, the Emden–Chandrasekhar equation is a dimensionless form of the Poisson equation for the density distribution of a spherically symmetric isothermal gas sphere subjected to its own gravitational force, named after Robert Emden and Subrahmanyan Chandrasekhar. The equation was first introduced by Robert Emden in 1907. The equation reads

where is the dimensionless radius and is the related to the density of the gas sphere as , where is the density of the gas at the centre. The equation has no known explicit solution. If a polytropic fluid is used instead of an isothermal fluid, one obtains the Lane–Emden equation. The isothermal assumption is usually modeled to describe the core of a star. The equation is solved with the initial conditions,

The equation appears in other branches of physics as well, for example the same equation appears in the Frank-Kamenetskii explosion theory for a spherical vessel. The relativistic version of this spherically symmetric isothermal model was studied by Subrahmanyan Chandrasekhar in 1972.

Fellow of the Royal Society

Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted to individuals that the Royal Society of London judges to have made a 'substantial contribution to the improvement of natural knowledge, including mathematics, engineering science and medical science'.

Fellowship of the Society, the oldest scientific academy in continuous existence, is a significant honour which has been awarded to many eminent scientists from history including Isaac Newton (1672), Charles Darwin (1839), Michael Faraday (1824), Ernest Rutherford (1903), Srinivasa Ramanujan (1918), Albert Einstein (1921), Winston Churchill (1941), Subrahmanyan Chandrasekhar (1944), Dorothy Hodgkin (1947), Alan Turing (1951) and Francis Crick (1959). More recently, fellowship has been awarded to Stephen Hawking (1974), Tim Hunt (1991), Elizabeth Blackburn (1992), Tim Berners-Lee (2001), Venkatraman Ramakrishnan (2003), Atta-ur Rahman (2006), Andre Geim (2007), James Dyson (2015), Ajay Kumar Sood (2015), Subhash Khot (2017), Elon Musk (2018) and around 8,000 others in total, including over 280 Nobel Laureates since 1900. As of October 2018, there are approximately 1689 living Fellows, Foreign and Honorary Members, of which over 60 are Nobel Laureates.Fellowship of the Royal Society has been described by The Guardian newspaper as “the equivalent of a lifetime achievement Oscar” with several institutions celebrating their announcement each year.

List of scientific constants named after people

This is a list of physical and mathematical constants named after people.Eponymous constants and their influence on scientific citations have been discussed in the literature.

  • Reduced Planck constant or Dirac constant (-bar, ħ) – Max Planck, Paul Dirac
List of things named after Subrahmanyan Chandrasekhar

The contents of this article is a list of things named after Subrahmanyan Chandrasekhar.

Chandrasekhar limit

Chandrasekhar friction

Chandrasekhar polarization

Chandrasekhar-Kendall function

Chandrasekhar's H-function

Schönberg–Chandrasekhar limit

Velikhov-Chandrasekhar instability

Batchelor–Chandrasekhar equation

Chandrasekhar–Page equation

Chandrasekhar's white dwarf equation

Chandrasekhar–Wentzel lemma

Chandrasekhar number

Emden–Chandrasekhar equation

Chandrasekhar tensor

Chandrasekhar virial equations

Chandrasekhar's X- and Y-function

Chandrasekhar's Variational Principle

Marjorie Hall Harrison

Marjorie Hall Harrison (September 14, 1918 – August 6, 1986) was an English-born American astronomer.

Hall was born in Nottingham, England in September 1918. In 1947, she authored one of the first scientific books, a dissertation while at the Yerkes Observatory of the University of Chicago, with the word "model" in the title. This work describes the processes that fuel stars and is among the first works that endeavored to create detailed mathematical models for complex physical systems. Along with Subrahmanyan Chandrasekhar, George Gamow and G. Keller, Harrison published models in 1944, 1946 and 1947 discussing stars modeled with hydrogen-depleted and isothermal cores. As a doctoral student of S. Chandrasekhar at the University of Chicago, she received a degree in astronomy in 1947.

A brother, Cecil Hall, was one of Eli Franklin Burton's graduate students who build the first practical electron microscope at the University of Toronto in 1938. Hall Harrison died in Huntsville, Texas in August 1986 at the age of 67.

William Alfred Fowler

William Alfred "Willy" Fowler (August 9, 1911 – March 14, 1995) was an American nuclear physicist, later astrophysicist, who, with Subrahmanyan Chandrasekhar won the 1983 Nobel Prize in Physics. He is known for his theoretical and experimental research into nuclear reactions within stars and the energy elements produced in the process.

1901–1925
1926–1950
1951–1975
1976–2000
2001–
present
Arts
Civil Service
Literature and Education
Medicine
Other
Public Affairs
Science and Engineering
Social Work
Sports
Trade and Industry
Copley Medallists (1951–2000)
Special
relativity
General
relativity
Scientists

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.