In the 1930s most astrophysicists believed that once stars burn up their fuel they collapse into small entities called ‘white dwarfs’. Subrahmanyan Chandrasekhar, a young Indian studying in England at that time, disagreed. He claimed that the 'white dwarf' theory was true only for stars that were similar in size to the sun; if the mass of a star were more than 1.4 times that of the sun, the star would, in fact, continue collapsing into an object of enormous density.
In 1935, Chandrasekhar was invited to present his theory to the prestigious Royal Astronomical Society. Among those present on the occasion was Arthur Eddington, a renowned British astrophysicist and young Chandrasekhar’s idol, who publicly ridiculed the paper.
“The star has to go on radiating and radiating and contracting and contracting until, I suppose, it gets to a few kilometres’ radius, when gravity becomes strong enough to hold the radiation and the star can at last have peace,” Eddington said, adding, bitingly, that this was a “reductio ad absurdum” of relativity theory. There must be a law of nature “to prevent a star from behaving in this absurd way!” the British scientist said.
Chandrasekhar would later describe this as a “painful experience”.
But Chandrasekhar’s theories and mathematics were proved right. The critical mass that he had predicted is now known as the Chandrasekhar Limit; objects of infinite density are called ‘black holes.’
The third of ten children of a Tamil couple, Chandrasekhara Subrahmanya Iyer and Sitalakshmi, Chandrasekhar—better known as “Chandra” to friends and colleagues in the United States—was born on 19 October 1910 in Lahore, then a part of British India. Subrahmanya Iyer was posted at the railways in Lahore at the time.
Science and scholarship ran in the family. Chandra’s paternal uncle, Chandrasekhara Venkata Raman, won the Nobel Prize in Physics in 1930 for discovering a form of light scattering known as the Raman Effect. Sitalakshmi, “a of woman high intellectual attainments” as her son later put it, had translated Henrik Ibsen’s A Doll's House into Tamil. “[She] was passionately devoted to her children, and was intensely ambitious for them,” Chandrasekhar said.
After completing his school education in Madras, Chandrasekhar studied at the city’s Presidency College, where he wrote his first paper, titled “The Compton Scattering and the New Statistics” in 1929 — he was not 20 yet. In recognition of his talent, he was awarded a Government of India scholarship to pursue higher education at England’s University of Cambridge. Around this time, white dwarfs had already started occupying his mind. While sailing to England, he is said to have studied the implications of relativity theory and the new Fermi-Dirac quantum statistical mechanics for stellar collapse.
For his final year of graduate studies he went to Copenhagen’s Institute for Theoretical Physics, where he met the famous Danish physicist Niels Bohr. In 1933, Chandrasekhar got a PhD degree at Cambridge. He married Lalitha Doraiswamy, whom he had known from his Presidency days, in 1936. In January 1937, Chandrasekhar joined the University of Chicago faculty as Assistant Professor. He would remain here for his entire career, becoming one of University’s much admired professors.
He became a United States citizen in 1953. Chandrasekhar developed a unique style of research, studying exhaustively in one area and then moving on to another, consequently mastering several fields of physics and astrophysics. As a result, his areas of research ranged from stellar structure to the theory of radiative transfer, and from the quantum theory of the negative ion of hydrogen to the mathematical theory of black holes.
In 1983 he was awarded the Nobel Prize in Physics for his work on the physical processes vital to the structure and evolution of stars. Chandrasekhar died after a sudden heart attack on 21 August 1995 in Chicago. He was 84.
His several decades of research and mentoring hundreds of students leave behind a rich legacy.
The maximum mass of a white dwarf star or the minimum mass that a star must exceed to eventually collapse into a neutron star or black hole—first calculated by a young Chandrasekhar when he was on a ship from India to England—is named after him. In 1999, NASA named a major observatory after him. The Chandrasekhar Number and an asteroid are also after named after him.
Chandrasekhar’s friend and colleague Eugene Parker was quoted as saying, in an obituary on the Indian-born scientist in The Scientist magazine: “One thing that stands out in my mind is that he [Chandrasekhar] was adamant that the highest standards be applied to science. He had very little patience for fuzzy-mindedness.”
Also on this day:
1920 — Pandurang Athavale, philosopher and spiritual leader, was born
1956 — Sunny Deol, Hindi film actor, was born
2003 — Mother Teresa, founder of the Missionaries of Charity, was beatified by Pope John Paul II
2011 — George Varghese Kakkanadan, Malayalam short story writer and novelist, passed away
