Sunday, October 19, 2008

Subrahmanyan Chandrasekhar: a birthday

Padma Vibhushan Subrahmanyan Chandrasekhar, FRS, was born on October 19th, 1902, in Panjab Lahore (British India, today: Pakistan) into a Tamil brahmin family. The name, Chandrasekhar, is one of Shiva's appellations: it means "holder of the moon" in Sanskrit.

Quite a good name for a guy who calculated the force keeping solid celestial bodies from collapsing.

His father was an achieved musician while his mother was a translator. He was their first kid but because they wanted him to be a perfect kid - like a dimension in critical superstring theory - they had 10 kids in total. ;-) Chandra's uncle, Chandrasekhara Venkata Raman, was a physics Nobel prize winner, too (for the Raman effect, inelastic scattering of photons off vibrational modes of molecules).

Chandra studied various local schools, the Presidency College, and was sent to Cambridge, U.K. with an Indian government scholarship. He was admitted to Trinity College: Ralph Fowler became his adviser. Paul Dirac told them it was a good idea for Chandra to meet Niels Bohr so Chandra spent a year in Copenhagen, too.

In 1933, he got his PhD and began to talk to Arthur Eddington and Edward Milne. Three years later, he married a one-year younger classmate Lalitha whose support was a "central fact of his life". In 1937, he moved to Chicago - because of reasons to be explained below - where he stayed. During the war, he worked on ballistics.

In physics, he meticulously divided his life into epochs. In each of them, he focused on one problem:
  • 1929-1939: stellar structure and white dwarfs
  • His book about the subject has 1,500 citations.
  • 1939-1943: stellar dynamics
  • His book about stellar dynamics has 600+ citations.
  • 1943-1950: hydrogen ion and radiative transfer
  • His book about radiative transfer has 4,000 citations.
  • 1950-1961: hydrodynamic and hydromagnetic stability
  • His book about the subject has 5,500 citations. Chandrasekhar number is a dimensionless ratio of the Lorentz force to the viscosity.
  • 1961-1971: GR & equilibrium figures
  • His book about the subject has 1,000 citations.
  • 1971-1983: black holes
  • His book about black holes has 1,500 citations.
  • 1983-1995: collisions of gravitational waves
  • See 100+ papers.
He was an organized guy, wasn't he? ;-) Physicists don't usually work in this way which is another reason to call him an applied mathematician. His 1983 Nobel prize was given to him for the first two epochs, especially for the Chandrasekhar limit from the first epoch (independently derived by Landau). He was angry that the rest of his life was ignored but he kindly accepted the award, anyway. ;-)

The Chandrasekhar limit is the upper bound on the mass of a white dwarf: if a star is heavier than 1.44 solar masses or so, it must become a neutron star or a black hole. Recall that white dwarfs are made out of electron-degenerate matter.

It means that there is some positive charge everywhere but the main obstacle preventing you from squeezing the star further is the "degeneracy" pressure from the electrons - from the Pauli exclusion principle. When you require this pressure to act against gravity, you will find out that its strength becomes insufficient if the mass exceeds the limit.

While the epochs above may indicate that Chandrasekhar was a mainstream "craftsman", it doesn't mean that his relativistic calculation was immediately accepted. Quite on the contrary. It was hysterically opposed by Arthur Eddington. Recall that Eddington has organized the over-hyped 1919 solar eclipse measurement and became a crackpot in the 1930s who had lots of "friends" among the journalists, much like Lee Smolin has today.

Although Chandrasekhar's relativistic calculation was clearly perfect, he didn't find any significant supporters among the established European physicists which was a source of immense frustration and one of his reasons to move to Chicago. That's yet another example of a stinky "consensus science". The only universal thing that "consensus" means in science is that people are cowards who are shitting into their pants.

Nothing has qualitatively changed since those times. Today, hundreds of string theorists are also shitting into their pants, being scared that the journalists (or crackpot Lee Smolin) will attack them in the media if they say what they actually know about physics. We still don't live in a scientific society. Our society is still led by fear, superstitions, charlatans, and crackpots.

At least in 2008, we don't have to be scared if we defend Chandrasekhar's calculations. The Chandra X-ray observatory is named after him, too. And when I say that Chandrasekhar was one of the best general relativists of the 20th century, I no longer have to be afraid of anything. ;-)

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