A teenager on a ship to England worked out how heavy dead stars can get
Sailing to Cambridge in 1930, a young Indian graduate spent the voyage adding relativity to the physics of collapsed stars. The upshot, now called the Chandrasekhar limit, says no white dwarf can exceed 1.44 solar masses. Heavier remnants collapse into neutron stars or black holes, and a Nobel Prize followed in 1983.
Subrahmanyan Chandrasekhar, known as Chandra, arrived on 19 October 1910 in Lahore, then part of British India and now in Pakistan, into a Tamil Brahmin family of ten children. His father audited the Northwestern Railways; his uncle was the Nobel physicist C. V. Raman; and his mother, who had translated Ibsen's A Doll's House into Tamil, is credited with sparking his curiosity. The family settled in Madras in 1918, and he was taught at home until he was 12.
At Presidency College in Madras he wrote his first paper in 1929, inspired by a lecture from Arnold Sommerfeld, and sent it to Ralph Fowler at Cambridge. Fowler helped secure him a government scholarship, and on the passage to England Chandra refined Fowler's treatment of the degenerate electron gas inside white dwarfs by allowing for electrons moving near light speed. His doctoral years took him to Max Born's institute in Göttingen and, on Paul Dirac's advice, to Copenhagen, where he met Niels Bohr.
In 1933 he won a Trinity College fellowship, only the second Indian to do so after Srinivasa Ramanujan. He was so sure he would be turned down that he had already rented a flat in Oxford to study under E. A. Milne. From 1937 until his death in 1995, aged 84, he taught at the University of Chicago, working partly at the Yerkes Observatory and editing The Astrophysical Journal from 1952 to 1971.
His range was enormous: stellar structure, radiative transfer, turbulence, general relativity, black holes and colliding gravitational waves. Revisiting how stars orbit the centre of the Milky Way, he solved a system of twenty partial differential equations and identified dynamical friction, a drag that slows stars and helps hold clusters together. NASA's Chandra X-Ray Observatory is among many things named in his honour.
Source: Subrahmanyan Chandrasekhar
