Subrahmanyan Chandrasekhar FRS (; listen ; 19
October 1910 – 21 August 1995) was an Indian
American astrophysicist who spent his professional
life in the United States. He was awarded
the 1983 Nobel Prize for Physics with William
A. Fowler for "...theoretical studies of the
physical processes of importance to the structure
and evolution of the stars". His mathematical
treatment of stellar evolution yielded many
of the best current theoretical models of
the later evolutionary stages of massive stars
and black holes. The Chandrasekhar limit is
named after him.
Chandrasekhar worked on a wide variety of
physical problems in his lifetime, contributing
to the contemporary understanding of stellar
structure, white dwarfs, stellar dynamics,
stochastic process, radiative transfer, the
quantum theory of the hydrogen anion, hydrodynamic
and hydromagnetic stability, turbulence, equilibrium
and the stability of ellipsoidal figures of
equilibrium, general relativity, mathematical
theory of black holes and theory of colliding
gravitational waves. At the University of
Cambridge, he developed a theoretical model
explaining the structure of white dwarf stars
that took into account the relativistic variation
of mass with the velocities of electrons that
comprise their degenerate matter. He showed
that the mass of a white dwarf could not exceed
1.44 times that of the Sun – the Chandrasekhar
limit. Chandrasekhar revised the models of
stellar dynamics first outlined by Jan Oort
and others by considering the effects of fluctuating
gravitational fields within the Milky Way
on stars rotating about the galactic centre.
His solution to this complex dynamical problem
involved a set of twenty partial differential
equations, describing a new quantity he termed
'dynamical friction', which has the dual effects
of decelerating the star and helping to stabilize
clusters of stars. Chandrasekhar extended
this analysis to the interstellar medium,
showing that clouds of galactic gas and dust
are distributed very unevenly.
Chandrasekhar studied at Presidency College,
Madras (now Chennai) and the University of
Cambridge. A long-time professor at the University
of Chicago, he did some of his studies at
the Yerkes Observatory, and served as editor
of The Astrophysical Journal from 1952 to
1971. He was on the faculty at Chicago from
1937 until his death in 1995 at the age of
84, and was the Morton D. Hull Distinguished
Service Professor of Theoretical Astrophysics.Chandrasekhar
married Lalitha Doraiswamy in September 1936.
He had met her as a fellow student at Presidency
College, Madras. Chandrasekhar was the nephew
of C. V. Raman, who was awarded the Nobel
Prize for Physics in 1930. He became a naturalized
citizen of the U.S. in 1953. Others considered
him as warm, positive, generous, unassuming,
meticulous, and open to debate, as well as
private, intimidating, impatient and stubborn
regarding non-scientific matters, and unforgiving
to those who ridiculed his work.
== Early life and education ==
Chandrasekhar was born on 19 October 1910
in Lahore, Punjab, British India (now Pakistan)
in a Tamil Hindu family, to Sitalakshmi (Divan
Bahadur) Balakrishnan (1891–1931) and Chandrasekhara
Subrahmanya Ayyar (1885–1960) who was stationed
in Lahore as Deputy Auditor General of the
Northwestern Railways at the time of Chandrasekhar's
birth. He had two elder sisters, Rajalakshmi
and Balaparvathi, three younger brothers,
Vishwanathan, Balakrishnan, and Ramanathan
and four younger sisters, Sarada, Vidya, Savitri,
and Sundari. His paternal uncle was the Indian
physicist and Nobel laureate C. V. Raman.
His mother was devoted to intellectual pursuits,
had translated Henrik Ibsen's A Doll's House
into Tamil and is credited with arousing Chandra's
intellectual curiosity at an early age. The
family moved from Lahore to Allahabad in 1916,
and finally settled in Madras in 1918.
Chandrasekhar was tutored at home until the
age of 12. In middle school his father would
teach him Mathematics and Physics and his
mother would teach him Tamil. He later attended
the Hindu High School, Triplicane, Madras
during the years 1922–25. Subsequently,
he studied at Presidency College, Madras from
1925 to 1930, writing his first paper, "The
Compton Scattering and the New Statistics",
in 1929 after being inspired by a lecture
by Arnold Sommerfeld. He obtained his bachelor's
degree, B.Sc. (Hon.), in physics, in June
1930. In July 1930, Chandrasekhar was awarded
a Government of India scholarship to pursue
graduate studies at the University of Cambridge,
where he was admitted to Trinity College,
Cambridge, secured by R. H. Fowler with whom
he communicated his first paper. During his
travels to England, Chandrasekhar spent his
time working out the statistical mechanics
of the degenerate electron gas in white dwarf
stars, providing relativistic corrections
to Fowler's previous work (see Legacy below).
In his first year at Cambridge, as a research
student of Fowler, Chandrasekhar spent his
time calculating mean opacities and applying
his results to the construction of an improved
model for the limiting mass of the degenerate
star. At the meetings of the Royal Astronomical
Society, he met E. A. Milne. At the invitation
of Max Born he spent the summer of 1931, his
second year of post-graduate studies, at Born's
institute at Göttingen, working on opacities,
atomic absorption coefficients, and model
stellar photospheres. On the advice of P.
A. M. Dirac, he spent his final year of graduate
studies at the Institute for Theoretical Physics
in Copenhagen, where he met Niels Bohr.
After receiving a bronze medal for his work
on degenerate stars, in the summer of 1933,
Chandrasekhar was awarded his PhD degree at
Cambridge with a thesis among his four papers
on rotating self-gravitating polytropes, and
the following October, he was elected to a
Prize Fellowship at Trinity College for the
period 1933–1937.
During this time, Chandrasekhar made acquaintance
with British physicist Sir Arthur Eddington.
In an infamous encounter at the Royal Astronomical
Society in London in 1935, Eddington publicly
ridiculed the concept of the Chandrasekhar
limit. Although Eddington would later be proved
wrong by computers and the first positive
identification of a black hole in 1972, this
encounter caused Chandrasekhar to contemplate
employment outside the UK. Later in life,
on multiple occasions, Chandrasekhar expressed
the view that Eddington's behavior was in
part racially motivated.
== Career and research ==
=== Early career ===
In January 1937, Chandrasekhar was recruited
to the University of Chicago faculty as assistant
professor by Otto Struve and President Robert
Maynard Hutchins. He was to remain at the
university for his entire career, becoming
Morton D. Hull Distinguished Service Professor
of Theoretical Astrophysics in 1952 and attaining
emeritus status in 1985. In 1953, he and his
wife, Lalitha Chandrasekhar, took American
citizenship. Famously, Chandrasekhar declined
many offers from other universities, including
one to succeed Henry Norris Russell, the preeminent
American astronomer, as director of the Princeton
University Observatory.
Chandrasekhar did some work at Yerkes Observatory
in Williams Bay, Wisconsin, which was run
by the University of Chicago. After the Laboratory
for Astrophysics and Space Research (LASR)
was built by NASA in 1966 at the University,
Chandrasekhar occupied one of the four corner
offices on the second floor. (The other corners
housed John A. Simpson, Peter Meyer, and Eugene
N. Parker.) Chandrasekhar lived at 4800 Lake
Shore Drive after the high-rise apartment
complex was built in the late 1960s, and later
at 5550 Dorchester Building.
=== World War II ===
During World War II, Chandrasekhar worked
at the Ballistic Research Laboratory at the
Aberdeen Proving Ground in Maryland. While
there, he worked on problems of ballistics,
resulting in reports such as 1943's On the
decay of plane shock waves, Optimum height
for the bursting of a 105mm shell, On the
Conditions for the Existence of Three Shock
Waves, and The normal reflection of a blast
wave. Chandrasekhar's expertise in hydrodynamics
led Robert Oppenheimer to invite him to join
the Manhattan Project at Los Alamos, but delays
in the processing of his security clearance
prevented him from contributing to the project.
It has been rumoured that he visited the Calutron
project, where he suggested that young women
be employed to operate the calutrons producing
enriched radioactive materials for the atomic
weapons.
=== Philosophy of systematization ===
He wrote that his scientific research was
motivated by his desire to participate in
the progress of different subjects in science
to the best of his ability, and that the prime
motive underlying his work was systematization.
"What a scientist tries to do essentially
is to select a certain domain, a certain aspect,
or a certain detail, and see if that takes
its appropriate place in a general scheme
which has form and coherence; and, if not,
to seek further information which would help
him to do that." Chandrasekhar developed a
unique style of mastering several fields of
physics and astrophysics; consequently, his
working life can be divided into distinct
periods. He would exhaustively study a specific
area, publish several papers in it and then
write a book summarizing the major concepts
in the field. He would then move on to another
field for the next decade and repeat the pattern.
Thus he studied stellar structure, including
the theory of white dwarfs, during the years
1929 to 1939, and subsequently focused on
stellar dynamics, theory of Brownian motion
from 1939 to 1943. Next, he concentrated on
the theory of radiative transfer and the quantum
theory of the negative ion of hydrogen from
1943 to 1950. This was followed by sustained
work on turbulence and hydrodynamic and hydromagnetic
stability from 1950 to 1961. In the 1960s,
he studied the equilibrium and the stability
of ellipsoidal figures of equilibrium, and
also general relativity. During the period,
1971 to 1983 he studied the mathematical theory
of black holes, and, finally, during the late
80s, he worked on the theory of colliding
gravitational waves.
=== Work with students ===
Chandra worked closely with his students and
expressed pride in the fact that over a 50-year
period (from roughly 1930 to 1980), the average
age of his co-author collaborators had remained
the same, at around 30. He insisted that students
address him as "Chandrasekhar" until they
received their Ph.D. degree, after which time
they (as other colleagues) were encouraged
to address him as "Chandra". When Chandrasekhar
was working at the Yerkes Observatory in 1940s,
he would drive 150 miles (240 km) to and fro
every weekend to teach a course at the University
of Chicago. Two of the students who took the
course, Tsung-Dao Lee and Chen-Ning Yang,
won the Nobel prize before he could get one
for himself. Regarding classroom interactions
during his lectures, noted astrophysicist
Carl Sagan stated from firsthand experience
that "frivolous questions" from unprepared
students were "dealt with in the manner of
a summary execution", while questions of merit
"were given serious attention and response".
=== Other activities ===
From 1952 to 1971 Chandrasekhar was editor
of The Astrophysical Journal. When Eugene
Parker submitted a paper on his discovery
of solar wind in 1957, two eminent reviewers
rejected the paper. However, since Chandra
as an editor could not find any mathematical
flaws in Parker's work, he went ahead and
published the paper in 1958.During the years
1990 to 1995, Chandrasekhar worked on a project
devoted to explaining the detailed geometric
arguments in Sir Isaac Newton's Philosophiae
Naturalis Principia Mathematica using the
language and methods of ordinary calculus.
The effort resulted in the book Newton's Principia
for the Common Reader, published in 1995.
Chandrasekhar was an honorary member of the
International Academy of Science.
== Personal life ==
Chandrasekhar died of a sudden heart attack
at the University of Chicago Hospital in 1995,
having survived a prior heart attack in 1975.
He was survived by his wife, Lalitha Chandrasekhar,
who died on 2 September 2013 at the age of
102. He was a serious student of literature
and western classical music.Once when involved
in a discussion about the Gita, Chandrasekhar
said, "I should like to preface my remarks
with a personal statement in order that my
later remarks will not be misunderstood. I
consider myself an atheist." This was also
confirmed many times in his other talks. In
an interview with Kevin Krisciunas at the
University of Chicago, on 6 October 1987,
Chandrasekhar commented: "Of course, he (Otto
Struve) knew I was an atheist, and he never
brought up the subject with me".
== Awards, honours and legacy ==
=== Nobel prize ===
Chandrasekhar was awarded the Nobel Prize
in Physics in 1983 for his studies on the
physical processes important to the structure
and evolution of stars. Chandrasekhar accepted
this honor, but was upset the citation mentioned
only his earliest work, seeing it as a denigration
of a lifetime's achievement. He shared it
with William A. Fowler.
=== Other awards ===
=== Legacy ===
Chandrasekhar's most notable work was the
astrophysical Chandrasekhar limit. The limit
describes the maximum mass of a white dwarf
star, ~1.44 solar masses, or equivalently,
the minimum mass which must be exceeded for
a star to ultimately collapse into a neutron
star or black hole (following a supernova).
The limit was first calculated by Chandrasekhar
in 1930 during his maiden voyage from India
to Cambridge, England for his graduate studies.
In 1979, NASA named the third of its four
"Great Observatories" after Chandrasekhar.
This followed a naming contest which attracted
6,000 entries from fifty states and sixty-one
countries. The Chandra X-ray Observatory was
launched and deployed by Space Shuttle Columbia
on 23 July 1999. The Chandrasekhar number,
an important dimensionless number of magnetohydrodynamics,
is named after him. The asteroid 1958 Chandra
is also named after Chandrasekhar. The Himalayan
Chandra Telescope is named after him. In the
Biographical Memoirs of the Fellows of the
Royal Society of London, R. J. Tayler wrote:
"Chandrasekhar was a classical applied mathematician
whose research was primarily applied in astronomy
and whose like will probably never be seen
again."Chandrasekhar guided 45 students to
their PhDs. After his death, his widow Lalitha
Chandrasekhar made a gift of his Nobel Prize
money to the University of Chicago towards
the establishment of the Subrahmanyan Chandrasekhar
Memorial Fellowship. First awarded in the
year 2000, this fellowship is given annually
to an outstanding applicant to graduate school
in the PhD programs of the Department of Physics
or the Department of Astronomy and Astrophysics.The
Chandra Astrophysics Institute (CAI) is a
program offered for high school students who
are interested in astrophysics mentored by
MIT scientists and sponsored by the Chandra
X-ray Observatory. American astronomer Carl
Sagan, who studied mathematics under Chandrasekhar
at the University of Chicago, praised him
in the book The Demon-Haunted World: "I discovered
what true mathematical elegance is from Subrahmanyan
Chandrasekhar." On 19 October 2017, Google
showed a Google Doodle in 28 countries honouring
Chandrasekhar's 107th birthday and the Chandrasekhar
limit.In 2010, on account of Chandra's 100th
birthday, University of Chicago conducted
a symposium titled Chandrasekhar Centennial
Symposium 2010 which was attended by leading
astrophysicists such as Roger Penrose, Kip
Thorne, Freeman Dyson, Jayant V. Narlikar,
Rashid Sunyaev, G. Srinivasan, and Clifford
Will. Its research talks were published in
2011 as a book titled Fluid flows to Black
Holes: A tribute to S Chandrasekhar on his
birth centenary.
== Publications ==
=== Books ===
=== Notes ===
=== Journals ===
Chandrasekhar had published around 380 papers
in his lifetime. He wrote his first paper
in 1928 when he was still an undergraduate
student about Compton effect and last paper
which was accepted for publication just two
months before his death was in 1995 which
was about non-radial oscillation of star.
The University of Chicago Press published
selected papers of Chandrasekhar in seven
volumes.
=== Books about Chandrasekhar ===
== References ==
== External links ==
Great Indians: Professor Subrahmanyan Chandrasekhar
– Video of Chandra's last interview at Chicago.
Audio – Subrahmanyan Chandrasekhar(1988)
The founding of general relativity and its
excellence[1]
Audio – Cain/Gay (2010) Astronomy Cast Chandrasekhar
National Academy of Sciences biography
Harvard's site on Chandrasekhar
Subrahmanyan Chandrasekhar
Subrahmanyan Chandrasekhar
Subramaniam Chandrashekhar
Bruce Medal page
Awarding of Bruce Medal: PASP 64 (1952) 55
Oral History interview transcript with Subrahmanyan
Chandrasekhar 17, 18 May 1977 & 31 October
1977, American Institute of Physics, Niels
Bohr Library and Archives
Oral History interview transcript with Subrahmanyan
Chandrasekhar 6 October 1987, American Institute
of Physics, Niels Bohr Library and Archives
Mathematics Genealogy Project
Concordia University Honorary Degree Citation,
June 1988, Concordia University Records Management
and Archives
National Academy of Sciences Biographical
MemoirObituariesBAAS 28 (1996) 1448
Obs 116 (1996) 121 comment
PASP 109 (1997) 73
QJRAS 37 (1996) 261
