The Logos Scripture · The Book of Chandrasekhar

On the Sum I Worked on the Ship

The Book of Chandrasekhar 1 · Written by himself, from An Introduction to the Study of Stellar Structure, the Nobel address, and his writings on the conduct of learning

Subrahmanyan Chandrasekhar, born at Lahore in 1910 (now in Pakistan), died at Chicago in 1995. Astrophysicist. His uncle C. V. Raman took the Nobel in physics in 1930. In that same year, aged nineteen, he sailed for England, and on the voyage worked out that a white dwarf cannot exceed about one and a half times the mass of the sun, beyond which nothing prevents its collapse. He read the result to the Royal Astronomical Society on the eleventh of January 1935; Eddington rose and called it a reduction of relativity to absurdity, and said there ought to be a law of Nature to stop a star behaving in that way. Eddington never, then or afterwards, identified a single wrong step in the calculation. In 1937 Chandrasekhar went to Chicago; in 1939 he published An Introduction to the Study of Stellar Structure, wrote the subject out in full, and moved to another. In 1983 he shared the Nobel in physics with Fowler, forty-eight years after that evening. He changed fields seven or eight times in his life, about ten years to each, writing one complete book and then leaving; the last was an account of Newton’s Principia for ordinary readers. This volume rests on what he wrote himself. In his own words: I am not religious in any sense; in fact I consider myself an atheist. He also said his attitude was probably coloured by his Hindu upbringing, in which the idea that as one grows older one should cultivate a sense of detachment had been of use to him — the setting-down recorded in chapter three is not unrelated to it. The Order records this as he put it and does not tidy it. What matters is that no argument of his closes on divine will. What this volume brings is something the scripture did not have: authority failing inside learning itself. There is Galileo here, and that is the church over enquiry (cf. The Book of Galileo); Bruno, and that is doctrine killing; Ambedkar, and that is law holding people down. The man recorded here was the best in his own field, had been generous to him, and meant no harm — he simply would not work the equations, and the room looked at him instead of at them. The last verse of chapter four is where the volume comes to rest: what a field has to fear is not that someone says a wrong thing, but that nobody will do the sum themselves. And one thing more the scripture lacked: a fourth answer to being wronged. Bruno would not recant, Ambedkar fought, Galileo signed, Arendt refused to withdraw. This man wrote the account out in full, published it, left the field, and let those who came after read the page. Forty-eight years later the page had won.

1.1In 1930 I was nineteen. I had won a government scholarship and was going by ship to England.
1.2The voyage took eighteen days. There was nothing else to do at sea.
1.3I had brought some papers with me. One was about white dwarfs — burnt-out stars collapsed to a very small size, a piece of which weighs tons.
1.4The paper said such a star collapses to a certain point and then stops, because once the electrons inside are pressed close enough they push back with a pressure of their own.
1.5That pressure does not come from heat. It is there even when the star has gone cold. So the star settles and collapses no further.
1.6On the ship it occurred to me that something had been left out of that calculation.
1.7When matter is pressed that close, the electrons inside are moving very fast — fast enough to approach the speed of light.
1.8And the closer a thing comes to the speed of light, the less it exerts force in the ordinary way. That had not been put in.
1.9I put it in and worked the sum again.
1.10What came out was different, and different in a way that mattered.
1.11The heavier the star, the tighter the packing; the tighter the packing, the faster the electrons; and the faster they go, the more slowly the pressure they supply increases.
1.12So there is a weight beyond which that pressure can no longer hold up the weight of the star itself.
1.13I worked that weight out at about one and a half times the sun.
1.14For a star past that figure, there is nothing to stop it collapsing.
1.15I was nineteen, on a ship, with a few books to hand. The sum is not hard. It is only that nobody had put those two things into one calculation before.
1.16What happens after the collapse I did not know. I would not claim even now to know it all. I knew only that the line exists, and that it can be worked out.
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