Subrahmanyan Chandrasekhar – Photo gallery
Astrophysicist Subrahmanyan Chandrasekhar, known as ‘Chandra’, photographed on 19 October 1983, the day he was awarded the Nobel Prize in Physics for his work on the evolution of stars.
Photo: Bettmann/Getty Images
Speed read: Death of a star & Alchemy in the stars
Death of a star
What happens to a star when it runs out of fuel and dies? In the 1920s, scientists assumed that when a star burns off all its energy supply its light fades, leaving behind the burnt-out and dense remains known as a white dwarf. Subrahmanyan Chandrasekhar was the first to show how the fate of a star lies in its own birth mass.
On a long sea voyage from India to England in 1930, Chandrasekhar passed the time by developing a theory that proposed that a stable white dwarf couldn’t be the fate of stars above a certain critical mass. According to his calculations, stars more than 1.4 times the mass of the Sun, which became known as the Chandrasekhar limit, must collapse under the force of their own weight, and be destined for a more spectacular fate.
It would take a generation of scientists to pinpoint precisely the fate of these larger stars, but in time it was proved that they do indeed go out with a bang, dying in a mammoth explosion called a supernova. If the original star was up to 2-3 times the mass of the Sun, the collapsed corpses left behind from the explosion end up as highly dense neutron stars. Stars that are more than 2-3 times the mass of the Sun suffer an even more exotic death – the force of gravity becomes so strong that matter disappears entirely into a black hole.
Chandrasekhar adopted a highly unusual approach to his research, investigating a fresh field of study each decade, such as how stars die, how radiation passes through a star’s atmosphere and the theory of black holes. Each decade he followed a similar routine; writing a series of papers that solved the unsolved problems in that field, before finally publishing a book that summarized his results and presented the whole field in a new and clearer light. However, it is mainly for his earliest triumph, inspired on the journey that began his voyage through the stars, that Chandrasekhar was awarded the 1983 Nobel Prize in Physics.
Alchemy in the stars
William A. Fowler, 1/2 of the prize
From the hydrogen and oxygen in the water we drink to the calcium in the bones that we are made of, chemical elements are the raw materials of life as we know it. But where do these elements come from? The 1983 Nobel Prize in Physics rewarded William Fowler’s efforts to show how all the natural elements in the Periodic Table are forged under extreme conditions during the course of a star’s lifetime.
The idea that stars can create elements within the intense temperatures and pressures found in their cores was first proved in 1939, when Hans Bethe showed that the Sun generates its heat and light by squashing hydrogen atoms together to form helium, releasing tremendous amounts of energy in the process. Almost 20 years later, Fowler, together with his colleagues Geoffrey and Margaret Burbidge and Sir Fred Hoyle, provided the definitive outline of how stars create all the elements from this primordial hydrogen and helium.
As a star ages, it eventually exhausts its hydrogen supply and begins to fuse its helium into carbon, once again releasing energy. Stars bigger than the Sun, which shine more furiously and under greater pressure, can fuse heavier elements than helium, creating all the elements up to iron. Creating heavier elements than iron requires the input of the vast amounts of energy produced when a large star dies in a tremendous supernova explosion. Under these extreme conditions, iron atoms can absorb more and more of the uncharged subcomponents of an atom, known as neutrons, leading to the creation of all the elements up to uranium. The explosion also blasts these elements across the universe to create more stars, planets and eventually life as we know it.
Fowler has continued to fine-tune our understanding of the nuclear reactions that form the elements within stars, both with theoretical calculations of the steps involved in the nuclear reactions and with experiments using particle accelerators to study the behaviour of elements. Through this shuttling between theory and experiment, Fowler is helping to shed further light on the formation of the chemical elements in the universe to help us understand how, as the astronomer Carl Sagan has famously said, “we are made of starstuff.”
William A. Fowler – Banquet speech
William A. Fowler’s speech at the Nobel Banquet, December 10, 1983
Your Majesties, Your Royal Highnesses, My Fellow Students, Ladies and Gentlemen,
You will note that my salutation includes my fellow students. Yes I am still a student. I even learned something from Professors Chandrasekhar and Taube two days ago. I came to Caltech as a new graduate student fifty years ago and I am now known as the oldest graduate student at Caltech. It’s nice to have a nickname like Willy: one doesn’t have to grow up. It is the great glory of the quest for human knowledge that, while making some small contribution to that quest, we can also continue to learn and to take pleasure in learning. Fellow students, there will be hard work and heart break in your futures but there will also be stimulating intellectual pleasure and joy. In less pompous language I call it fun.
This happy occasion includes some sadness for me. My darling wife, Ardiane, is unable to be with me. She has shared my trials and tribulations and my minor triumphs – what a pity she cannot share this supreme moment with me. Our daughters, Mary and Martha, we call them our biblical characters, are with me. For them, Ardie is a caring mother, for me she is a loving wife.
I am told that Nobel Laureates soon come to be considered experts in all fields. It won’t happen to me and to prove it I’ll tell an old apocryphal story of mine which shows my feelings about so-called experts. I think it is fair to say we all look up to medical doctors as experts. Well, more or less. When you are ill you go to your doctor, he diagnoses your problem, prescribes treatment and you do what he tells you – he is the expert.
Anyhow, a few years ago I sprained my left wrist while on a trip away from home. I went to a doctor recommended by a friend. He took X-rays, found no broken bones, gave me some pain-killer and dismissed me. But as I was leaving his office he said, “I want you to bathe that wrist in hot water three times a day.” I was flabbergasted! “Doctor,” I said, “What do you mean? My mother told me always to bathe a sprain in ice water.” “Well, your mother was wrong,” he replied, “my mother told me to bathe a sprain in hot water.” So much for experts!
My work is my life. For the first thirty years of my career I was an experimentalist. For the last twenty years I have been trying to analyze in the simplest possible theoretical way what I was doing in the laboratory and what others continue to do in laboratories around the world. For me it is still a source of amazement that we can duplicate in the laboratory in a small way what goes on in the sun and other stars.
In regard to the many problems facing mankind at the present time I feel that there are two major ones of equal importance – overpopulation and the nuclear arms race. I have no expert competence in regard to the solution of either of these problems but as a concerned human being I support with equal fervor a population freeze and a nuclear freeze. This is not the appropriate time to elaborate on these devastating problems.
I have many friends in Sweden and it is a pleasure to be reunited with them if only for a short time. For that and for the honor accorded to me I am indebted to the Royal Swedish Academy of Science and, for making our visit so pleasant, to the Nobel Foundation and Britta Andreen. I accept with great joy my share of the 1983 Nobel Prize in Physics. Thank you.
Subrahmanyan Chandrasekhar – Nobel Lecture
Nobel Lecture, December 8, 1983
On Stars, Their Evolution and Their Stability
Read the Nobel Lecture
Pdf 275 kB
William A. Fowler – Nobel Lecture
Nobel Lecture, December 8, 1983
Experimental and Theoretical Nuclear Astrophysics; the Quest for the Origin of the Elements
Read the Nobel Lecture
Pdf 1.06 MB
Subrahmanyan Chandrasekhar – Banquet speech
Subrahmanyan Chandrasekhar’s speech at the Nobel Banquet, December 10, 1983
Your Majesties, Your Royal Highnesses, Ladies and Gentlemen,
The award of a Nobel Prize carries with it so much distinction and the number of competing areas and discoveries are so many, that it must of necessity have a sobering effect on an individual who receives the Prize. For who will not be sobered by the realization that among the past Laureates there are some who have achieved a measure of insight into Nature that is far beyond the attainment of most? But I am grateful for the award since it is possible that it may provide a measure of encouragement to those, who like myself, have been motivated in their scientific pursuits, principally, for achieving personal perspectives, while wandering, mostly, in the lonely byways of Science. When I say personal perspectives, I have in mind the players in Virginia Woolf’s The Waves:
There is a square; there is an oblong. The players take the square and place it upon the oblong. They place it very accurately; they make a perfect dwelling-place. Very little is left outside. The structure is now visible; what is inchoate is here stated; we are not so various or so mean; we have made oblongs and stood them upon squares. This is our triumph; this is our consolation.
May I be allowed to quote some further lines from a writer of a very different kind. They are from Gitanjali, a poem by Rabindranath Tagore who was honoured on this same date exactly seventy years ago. I learnt the poem when I was a boy of twelve some sixty and more years ago; and the following lines have remained with me ever since:
Where the mind is without fear and the head is held high;
Where knowledge is free;
Where words come out from the depth of truth;
Where tireless striving stretches its arms towards perfection;
Where the clear stream of reason has not lost its way into the dreary desert sand of dead habit;
into that haven of freedom, Let me awake.
May I, on behalf of my wife and myself, express our immense gratitude to the Nobel Foundation for this noble reception in this noble city.
William A. Fowler – Other resources
Links to other sites
‘William Fowler and Elements in the Stars’ from DOE R&D Accomplishments
William A. Fowler – Prize presentation
Subrahmanyan Chandrasekhar – Prize presentation
Watch a video clip of the 1983 Nobel Laureate in Physics, Subramanyan Chandrasekhar, receiving his Nobel Prize medal and diploma during the Nobel Prize Award Ceremony at the Concert Hall in Stockholm, Sweden, on 10 December 1983.
William A. Fowler – Photo gallery
HM Queen Silvia of Sweden flashes a smile while conversing with William Alfred Fowler at the Nobel Banquet in the Stockholm City Hall, Sweden, on 10 December 1983.
© Svensk Reportagetjänst 1983
Photo: Ulf Blumenberg