Wednesday, January 1, 2020

Biography of Subrahmanyan Chandrasekhar

Subrahmanyan Chandrasekhar (1910-1995) was one of the giants of modern astronomy and astrophysics in the 20th Century. His work connected the study of physics to the structure and evolution of stars and helped astronomers understand how stars live and die. Without his forward-thinking research, astronomers might have labored far longer to comprehend the basic nature of stellar processes that govern how all stars radiate heat to space, age, and how the most massive ones ultimately die. Chandra, as he was known, was awarded the 1983 Nobel Prize in physics for his work on the theories that explain the structure and evolution of stars. The orbiting Chandra X-Ray Observatory is also named in his honor. Early Life Chandra was born in Lahore, India on October 19th, 1910. At the time, India was still part of the British Empire. His father was a government service officer and his mother raised the family and spent much time translating literature into the Tamil language. Chandra was the third oldest of ten children and was educated at home until the age of twelve. After attending high school in Madras (where the family moved), he attended Presidency College, where he received his bachelors degree in physics. His honors standing afforded him a scholarship for graduate school to Cambridge in England, where he studied under such luminaries as P.A.M. Dirac. He also studied physics in Copenhagen during his graduate career. Chandrasekhar was awarded a Ph.D. from Cambridge in 1933 and was elected to a fellowship at Trinity College, working under astronomers Sir Arthur Eddington and E.A. Milne.   Development of Stellar Theory Chandra developed much of his early idea about stellar theory while he was on his way to begin graduate school. He was fascinated with mathematics as well as physics, and immediately saw a way to model some important stellar characteristics using math. At the age of 19, onboard a sailing ship from India to England, he began thinking about what would happen if ​Einsteins theory of relativity could be applied to explain the processes at work inside stars and how they affect their evolution. He worked out calculations that showed how a star much more massive than the Sun would not simply burn up its fuel and cool, as astronomers of the time assumed. Instead, he used to physics to show that a very massive stellar object would actually collapse to a tiny dense point—the singularity of a black hole. In addition, he worked out whats called the Chandrasekhar Limit, which says that a star with a mass 1.4 times that of the Sun will almost certainly end its life in a supernova exp losion. Stars many times this mass will collapse at the ends of their lives to form black holes. Anything less than that limit will stay a white dwarf forever. An Unexpected Rejection Chandras work was the first mathematical demonstration that such objects as black holes could form and exist and the first to explain how mass limits affected stellar structures. By all accounts, this was an amazing piece of mathematical and scientific detective work. However, when Chandra arrived at Cambridge, his ideas were soundly rejected by Eddington and others. Some have suggested that endemic racism played a role in the way Chandra was treated by the better-known and apparently egotistical older man, who had somewhat contradictory ideas about the structure of stars. It took many years before Chandras theoretical work was accepted, and he actually had to leave England for the more accepting intellectual climate of the United States. Several times after that, he mentioned the overt racism he faced as a motivation for moving forward in a new country where his research could be accepted regardless of his skin color. Eventually, Eddington and Chandra parted cordially, despite the o lder mans previous disdainful treatment. Chandras Life in America Subrahmanyan Chandrasekhar arrived in the U.S. at the invitation of the University of Chicago and took up a research and teaching post there that he held for the rest of his life. He plunged into studies of a subject called radiative transfer, which explains how radiation moves through matter such as the layers of a star such as the Sun). He then worked on extending his work on massive stars. Nearly forty years after he first proposed his ideas about white dwarfs (the massive remains of collapsed stars) black holes and the Chandrasekhar Limit, his work was finally widely accepted by astronomers. He went on to win the Dannie Heineman prize for his work in 1974, followed by the Nobel Prize in 1983. Chandras Contributions to Astronomy Upon his arrival in the United States in 1937, Chandra worked at the nearby Yerkes Observatory in Wisconsin. He eventually joined NASAs Laboratory for Astrophysics and Space Research (LASR) at the University, where he mentored a number of graduate students. He also pursued his research into such varied areas as stellar evolution, followed by a deep dive into stellar dynamics, ideas about Brownian motion (the random motion of particles in a fluid), radiative transfer (the transfer of energy in the form of electromagnetic radiation), quantum theory, all the way to studies of black holes and gravitational waves late in his career. During World War II, Chandra worked for the Ballistic Research Laboratory in Maryland, where he was also invited to join the Manhattan Project by Robert Oppenheimer. His security clearance took too long to process, and he was never involved with that work. Later in his career, Chandra edited one of the most prestigious journals in astronomy, the Astrophysical Journal. He never worked at another university, preferring to stay at the University of Chicago, where he was Morton D. Hull Distinguished Professor in astronomy and astrophysics. He retained emeritus status in 1985 after his retirement. He also created a translation of Sir Isaac Newtons book Principia that he hoped would appeal to regular readers. The work, Newtons Principia for the Common Reader,  was published just before his death.   Personal Life Subrahmanyan Chandrasekhar was married to Lalitha Doraiswamy in 1936. The couple met during their undergraduate years in Madras. He was the nephew of the great Indian physicist C.V. Raman (who developed the theories of light scattering in a medium that carry his name). After emigrating to the United States, Chandra and his wife became citizens in 1953. Chandra wasnt just a world leader in astronomy and astrophysics; he was also devoted to literature and the arts. In particular, he was an ardent student of western classical music. He often lectured on the relationship between the arts and the sciences and in 1987, compiled his lectures into a book called Truth and Beauty: the Aesthetics and Motivations in Science,  focused on the confluence of the two topics. Chandra died in 1995 in Chicago after suffering a heart attack. Upon his death, he was saluted by astronomers around the world, all of whom have used his work to further their understanding of the mechanics and evolution of stars in the universe. Accolades Over the course of his career, Subrahmanyan Chandrasekhar won many awards for his advancements in astronomy. In addition to those mentioned, he was elected a fellow of the Royal Society in 1944, was given the Bruce Medal in 1952, the Gold Medal of the Royal Astronomical Society, the Henry Draper Medal of the U.S. National Academy of Sciences, and the Humboldt Prize. His Nobel Prize winnings were donated by his late widow to the University of Chicago to create a fellowship in his name.

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