Subramanya Chandrasekhar : A tribute (1999)

The Tribune , Chandigarh, 27 July 1999

INDIA -BORN US ASTROPHYSICIST
Chandra observatory: tribute to a legend
 Rajesh Kochhar

The recent X-ray observatory launched into space by the USA has been named Chandra after the India-born American astrophysicist. This is a befitting tribute by the USA to a man who did much to invigorate American astronomy.

Chandrasekhar, popularly called Chandra, came to the USA in 1937 as a scientific refugee from Europe, after spending his seven most creative years at Cambridge University. He was the first person to apply the theory of special relativity to astronomy. He showed that there is an upper limit to the mass of a white dwarf. (This limit is now known as the Chandrasekhar Limit.) What happens if the white dwarf mass is higher than the Chandrasekhar Limit? In what must rank as the understatement of the century, Chandrasekhar declared: “One is left speculating on other possibilities.”

The other possibilities, of course, are the neutron star and the black hole, whose properties the Chandra observatory would study.

The course of astronomical history would have been different if Chandrasekhar’s work, mathematically rigorous as it was, had received immediate recognition. But at that time it met with ridicule at the hands of the most influential astronomer of the day, Sir Arthur Eddington, who declared with a haughtiness one associates with a viceroy rather than scientists: “I think there should be a law of nature to prevent a star from behaving in this absurd way.”

Sir Arthur was blinded by his self-righteousness, the rest of Europe by the glare of his personality. For four long frustrating years, Chandrasekhar tried to enlist support from among the physicists and astronomers but to no avail.

Sir Arthur’s hostility delayed the development of the subject by a generation. The discovery of quasars in 1963 and of radio pulsars in 1967 proved that relativistic astrophysics was not merely a mathematical artifact but also had the sanction of direct observation. Chandrasekhar could have got the Nobel Prize anytime after 1967 but not before this. (He got it 16 years later, in 1983). It was, however, not till 1974 that a medal awarded to Chandrasekhar referred to his white dwarf work.

Sir Arthur’s academic hostility robbed Chandrasekhar of his innocence. He moved to the USA (“Out there we don’t believe in Eddington”), resolving not to hanker after recognition but to let his work speak for itself. Henceforth mathematics would be his ally and time his judge.

As if to provide a physical basis to his resolve, Chandrasekhar bade goodbye to his first love, stellar structure. He would take on a new subject, write a definitive treatise on it and move on. Significantly, while his first work was the first word on the subject, his subsequent works have tended to be the last word. Even without the white dwarf work, Chandrasekhar would have been an outstanding astrophysicist, but he would not have won the Nobel Prize.

A few years ago, during one of his visits to Bangalore, I asked Chandrasekhar what was more satisfying, saying the first word or the last. His answer was rather long and involved. He first educated me who had first used the terms “first word” and “last word”. He then analysed the works of French and other painters. Regrettably, his efforts to raise my aesthetic sensibilities failed. All I learnt was that I was not getting a reply to my question.

It was indeed a bold step for Chicago University and the Yerkes Observatory to hire Chandrasekhar, who was the first non-white member of the faculty. He more than repaid the consideration shown to him. His outsidedness was put to good use when he edited the Astrophysical Journal for 19 strenuous years, “and turned it into a world-class publication.” He was, however, never offered the presidentship of the American Astronomical Society.

In 1966, he was given the National Medal of Science by the American President. It was the first time that the medal went to an astronomer. The citation made specific reference to Chandrasekhar’s contribution to the training of manpower.

He had an extraordinarily retentive memory. In August, 1949, he wrote to a friend: “I recall replying to your letter of June 6, 1937.” In 1992, I had an occasion to discuss with him an incident that had taken place in 1927: how at an international conference in Cuomo, Italy, D.M. Bose turned up much to the chagrin of the organisers who had wished to see S.N. Bose instead. Chandrasekhar heard the story from his friend, K.S. Kushnan, who in turn had heard it from the aggrieved Bose. Chandrasekhar recalled the details in his 1992 letter, closing it with a finality: “My recollection of the story is quite distinct and I am sure it reproduces exactly what Krishnan told me.”

Chandrasekhar began his white dwarf work when he was still a student at Presidency College, Chennai. Could India have retained him?

Chandrasekhar’s tiff with Eddington had its effect on his fortunes in British India. From 1935 till 1944, Chandrasekhar remained in the doghouse. His rehabilitation came in 1944 with his election as a fellow of the Royal Society (where Eddington was one of his sponsors). After that he received a number of offers. First, there was this invitation from his overbearing uncle, C.V. Raman, to join the Indian Institute of Science, Bangalore, an offer Chandrasekhar could not have accepted. He could have joined Banaras Hindu University, where the Vice-Chancellor, S. Radhakrishnan, was keen to appoint him.

Why is it that any of these initiatives failed to produce results? Two years ago. I had the opportunity, with Mrs Lalita Chandrasekhar’s permission, to go through some (but not all) of the Chandrasekhar Papers deposited at the Chicago university. (The visit to Chicago, in turn, was made possible by a Fulbright grant). My own impressionistic answer is as follows.

There was a difference of perception between Chandrasekhar on the one hand and his family and advisers back home on the other. Left to himself, he would have accepted Homi Bhabha’s offer to come to Tata Institute of Fundamental Research, Mumbai. His father and advisers, however, wished to see him as the Director of the Kodaikanal Observatory, a well-known astronomical centre in South India. Chandrasekhar, however, did not have any intention of accepting an administrative post, and wanted a university-like setting.

In his authorised biography by K.C. Wali, Chandrasekhar confirms this: “Left to myself I would have been tempted by Bhabha’s offer to a greater extent than I was. But I was advised against it by several people.”

His acceptance of American citizenship in 1953 put paid to all questions of returning. He would gladly have accepted a part-of-year professorship, but none came his way. Finally, on his retirement, there was again this possibility of returning home, but efforts remained half-hearted and ceased after a while.

What course would Indian science and education have taken if Chandrasekhar had returned? No doubt, he would have trained a large number of researchers, who in course of time would have occupied important positions in the Indian academy. Would Chandrasekhar’s total commitment to science have become the guiding principle for his students also? Would his conscientious negation of administrative and executive powers been emulated? In his own words, one is left speculating on the possibilities. As it turned out, in his native land, Chandrasekhar became an icon, a showboy, even a tool, but never a teacher or guide or a role model.

Chandrasekhar was a citizen of the world. He was an American by residence, European by training, but an Indian not only by birth but also by affiliations. In probably an unguarded moment, he wrote in a personal letter (1979): “You say that it never rains — it pours. “For me it seems to be always barren”.

(The author is a Professor at the Indian Institute of Astrophysics, Bangalore.)