Dr S Chandrasekhar
Subrahmanyan Chandrasekhar’s name will figure very high on any list of the greatest scientists India has produced. In the words of fellow Nobel laureate Hans Bethe, he “was one of the greatest astrophysicists of our time. He showed that white dwarf stars cannot grow beyond a certain mass—the same mass that triggers the explosion of supernovae, the most brilliant display in the sky.” Interestingly Bethe adds: “Chandra was also the greatest master of the English language that I know,” a view that is easily enhanced by a reading of his Nobel acceptance speech, reproduced on the facing page.
The Nobel Prize in Physics in 1983 was awarded to Dr Chandrasekhar, University of Chicago, Chicago, USA, for his theoretical studies of the physical processes of importance to the structure and evolution of the stars, and William A Fowler, California Institute of Technology, Pasadena, USA, for his theoretical and experimental studies of the nuclear reactions of importance in the formation of the chemical elements in the universe.
Chandrasekhar was born on October 19, 1910 to C Subrahmanya Ayyar and his wife Sita, in Lahore, where Ayyar had been posted by the Government of India as the Deputy Auditor General of the Northwestern Railways. Until the age of twelve, “Chandra” was educated at home, by his parents and private tutors. His mother, in his own words, “was a woman of high intellectual attainments (she translated into Tamil, for example, Ibsen’s A Doll House) and passionately devoted to her children, and was intensely ambitious for them.”
Moving to Madras on his father’s transfer, Chandrasekhar attended the well known Hindu High School and later Presidency College, where he obtained a BSc degree in Physics. Winning a Government of India scholarship for postgraduate studies in Cambridge University, he set sail for England at the age of 19, in 1930.
On that maiden voyage, Chandra developed a theory about the nature of stars that challenged the scientific notion then prevalent, that “all stars, after burning up their fuel, became faint, planet-sized remnants known as white dwarfs.” Stars with a mass greater than 1.4 times that of the sun—now known as the “Chandrasekhar mass”—must eventually collapse past the stage of a white dwarf into an object of such enormous density that one is left speculating on other possibilities, he wrote.
According to Chandra’s theory, when the nuclear energy in the centre of the star is exhausted, it collapses to form a white dwarf, only if the mass is below a certain limit. The star is so named because of its reduction in size, leading to an increase in its density to about 10 tons per cc.The collapse in slightly heavier stars can lead to an explosion and the formation of neutron stars, which have a density of 100 million tons per cc. The still heavier stars, on collapsing, will form black holes where the density is so high that even light, emitted from within the black hole, can not escape to the outside world.
His theory was rejected, even ridiculed by his peers and professional journals. Disappointed, Chandrasekhar moved to the US, and joined the
faculty of University of Chicago in 1937, a year after marrying Lalitha Doraiswamy, his junior by a year at Presidency College, Madras.
There, he was to work for the rest of his life, making original contributions to the science of astrophysics. `Chandrasekhar’s theory of black holes, which is a central part of contemporary astrophysics, eventually won him the Nobel Prize in 1983—53 years after he first propounded it.
His work dealt with many features in stellar evolution and the stability problems in different phases of evolution. Later, he studied relativistic effects, important in the context of the extreme conditions arising during the last stages of stellar evolution.
It was his pioneering work that laid the foundation for later developments in astronomy and space research. Chandrasekhar was also widely admired for his appreciation of literature, music and the philosophy of science. His research explored many branches of theoretical astrophysics and he published ten books, each on a different topic. One of his important books was “Newton’s Principia for the Common Reader”, translating Sir Isaac Newton’s Principia Mathematica into the language of modern mathematics, an example of Chandra’s multifaceted contributions to the world of science, literature, history and art.
He was the editor of the Astrophysical Journal for 18 years, presided over a thousand colloquia, and supervised PhD research for more than 50 students. (So devoted was he to students that in the 1940s, he drove more than 100 miles each week to teach just two of them. It was well worth the trouble Chandra took, for the students—T D Lee and C N Yang—went on to win the Nobel Prize in Physics). He received 20 honorary degrees, was elected to 21 learned societies and received numerous other awards.
When Chandrasekhar died on August 21, 1995, tributes poured in from some of the greatest scientific minds of the day.
Martin Rees, Great Britain’s Astronomer Royal: “Chandra probably thought longer and deeper about our universe than anyone since Einstein.” Martin Schwarzschild professor of astronomy emeritus at Princeton University:
“There is total unanimity among astronomers that Chandra, as a mathematical astrophysicist, was the greatest of our generation.
I was also enormously fond of Chandra as a person, and he was a glorious friend.” Eugene Parker, professor emeritus at University of Chicago: “Chandra’s unique strength was his combination of a fundamental understanding of physical concepts and his phenomenal mathematical ability. He combined those strengths to forge an immensely productive career…”
The life Dr Chandrasekhar led, the wide sweep of his interests, his complete dedication to science and his philosophy of life based on a firm belief in the interrelatedness of things, can be surmised from the title of one of his books, “Truth and Beauty: Aesthetics and Motivations in Science.”
Subrahmanyan Chandrasekhar’s speech at the Nobel Banquet, December 10, 1983
Your Majesties, Your Royal Highness, Ladies and Gentlemen, The award of a Nobel Prize carries with it so much distinction as the number of competing areas and discoveries are so many, that it must of necessity have a sobering effect on an individual who receives the Prize.
For who will not be sobered by the realisation that among the past Laureates there are some who have achieved a measure of insight into Nature that is far beyond the attainment of most? But I am grateful for the award since it is possible that it may provide a measure of encouragement to those, who like myself, have been motivated in their scientific pursuits, principally, for achieving personal perspectives, while wandering, mostly, in the lonely byways of Science. When I say personal perspectives, I have in mind the players in Virginia Woolf’s The Waves: There is a square; there is an oblong. The players take the square and play it upon the oblong. They place it very accurately; they make a perfect dwelling-place. Very little is left outside. The structure is now visible; what is inchoate is here stated; we are not so various or so mean; we have made oblongs and stood them upon squares. This is our triumph; this is our consolation. May I be allowed to quote some further lines from a writer of a very different kind? They are from Gitanjali, a poem by Rabindranath Tagore who was honoured on this same date exactly seventy years ago. I learnt the poem when I was a boy of twelve some sixty and more years ago; and the following lines have remained with me ever since:
Where the mind is without fear and the head is held high;
Where knowledge is free;
Where the world has not been broken up into fragments by narrow domestic walls;
Where words come out from the depth of truth;
Where tireless striving stretches its arms towards perfection;
Where the clear stream of reason has not lost its way into the dreary desert sand of dead habit;
Where the mind is led forward by thee into ever-widening thought and action—
Into that heaven of freedom, my Father, let my country awake.