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Simranjit Kaur
posted on: 29 Mar, 2022
Piara Singh Gill - A persevering Sikh Scientist who served as a Beacon of Light in Cosmic Ray Research

Piara Singh Gill was a well-known physicist who specialized in cosmic ray research. His tenacity is evident in his journey from walking 10 kilometres to attend school in a rural Pakistani village to receiving grants from top universities in the United States. His days of difficulty included driving cabs, gathering fruit, and cleaning floors, all of which helped him develop total discipline, allowing him to eventually become an internationally renowned physicist whose work is still valued today.


Piara Singh Gill

Early Life

Piara Singh Gill was born in the village of Chela in the district of Hoshiarpur, Punjab, on October 28, 1911. He was raised as a Sikh in an orthodox Sikh family who practised farming. He spent his youth listening to Akhand Paths (a continuous recitation of Guru Granth Sahib Ji day and night till its completion). His father moved to South Africa in the hopes of making a fortune, but returned after being abused by boers. He believed that his lack of education was a major impediment to his success, so he set out to educate his boys. Gill's two brothers were sent to school to study, but they refused because they were afraid of being punished severely. His father then turned his attention to Piara Singh to satisfy his wants. He was frequently bribed and threatened with being sent to school. The way to his school ran through a deep forest filled with wolves waiting to attack. Despite his strenuous farm work, his father took up the responsibility of accompanying him to and from school. As a result of his father's efforts, he was accepted to Khalsa College and received his matriculation certificate [1]. 

Journey To USA

In 1922, his older brother was a member of the Babbar Akali Movement, which was fighting for independence. Piara Singh was persuaded to move to America by him and his pals. He used to wonder about the New World and admire the folks who visited there when he was in high school. However, because the majority of them were illiterate, they could only tell him about the abundance of fruits, roads, and automobiles. His acquaintance, Lalu Singh, had visited the United States three times and was well knowledgeable about the topography of the Panama Canal. Piara Singh was enthralled by his endless stories of his experiences [1]. 

He began focusing on his goal of travelling to America after passing his final exams in 1929. Securing a passport and obtaining adequate finances for the trip were among the challenges he faced. Because of his brother's political connections, obtaining a passport was nearly impossible. He and Hari Singh then travelled to Mumbai, where a bribe enabled them to obtain a passport for him. However, obtaining a visa proved to be a difficult affair. His father's friend obtained a Panama entry permit with the intention of entering the United States via a different route [1].

Piara Singh arrived in Mumbai by train and subsequently boarded the S.S Carlo, an Italian freighter, in May 1929. His money had depleted by the time he arrived in Panama, so he toiled for 10 months before returning to the United States and working odd jobs like washing floors and gathering fruit during the Great Depression. He received a student visa after securing a spot at the University of California through Dr. Bhag Singh, who was a student there. He was accepted as a full-time student at Sacramento Junior College in August 1931. Every student, including international students, was admitted for free. He received a scholarship to the University of Southern California after finishing two years of undergraduate studies. He took two mathematics courses and worked part time to afford his expenses. During summer vacations, he also worked as an extra in movies, one of the famous ones was "Lives of Bengal Lancers". He secured a BSc.and MSc. in mathematics and physics where he earned a merit-based scholarship [2]. He published his MSc thesis on "Electromagnetic and Electrostatic Forces in Electron Beams" in May,1936. In the thesis, Gill proposed a method to produce extremely high pressures in gases with the help of means other than mechanical compression. The most common method to achieve this was the bombardment of elements by high-energy protons, deutons, and alpha-particles. But, as it was evident, a very small fraction of bombardments could actually result in nuclear transformation. So, the need to devise a different pathway arised which involved conversion of a proton into a neutron. His calculations showed that this method of producing highly compressed electron proton beams is promising [6]. 

First Publication and Early Scientific Journey

Later, in October 1936, he enrolled at the University of Chicago, where he studied physics with Nobel Laureate Arthur Holy Compton. He began his research career in 1937 and focused on the Time Variation of Cosmic Rays, which he excelled at. Data was acquired using an ionisation chamber protected by 12 cm of lead put on board the R M S Aorangi, which traversed the Pacific Ocean from Vancouver, BC to Hobart, Tasmania. After accounting for the temperature effect, the results proved the latitude effect of cosmic rays at sea level. He published these findings in his first research paper titled “Further Study of Cosmic Rays on the Pacific Ocean” co-authored with William P. Jesse in 1939 in the journal “The Physical Review”. They confirmed the correlation between the cosmic-ray intensity and the atmospheric temperature, which was incompatible with the galactic rotation effect. The tiny magnitude of the latitude effect was demonstrated, which provided significant evidence for mesotrons' secondary nature. An atmospheric temperature coefficient was found to be a function of latitude, with its highest numerical value of —0.25 percent per 'C for latitudes higher than 40' (N and S). With this variable temperature coefficient, a latitude effect (about 8.5 percent) of magnetic origin alone was determined. The difference of  0±0.1 percent (probable error) was calculated in cosmic-ray intensity between the Northern and Southern Hemispheres beyond the critical latitudes after this temperature correction [4].

In its June 30, 1939, issue, the New York Times featured his and his partner Marcel Schein's work under the headline "Cosmic Bullets Make Atom Dust." In March 1940, he received his doctorate degree in Physics at the 199th Convocation of the University of Chicago [2]. He attended an international symposium on cosmic rays at the University of Chicago in June 1939, where he met half a dozen Nobel Laureates from around the world. Gill was one of the younger participants who presented a paper on the Size Frequency Distribution of Cosmic-Ray Bursts with Dr. Marcel Schein. This work piqued physicists' curiosity because it was the first to reveal information about the spin of the meson [12. He co-authored his second paper, "Cosmic Rays on the Pacific Ocean" with A. H. Compton. He wanted to study the distribution of cosmic rays over the Pacific Ocean to establish the relative densities in the northern and southern hemispheres. According to the theory of the galactic rotation effect, if cosmic rays do not share the galaxy's rotational motion, the intensity in the Northern Hemisphere should be around 0.5 percent higher than in the Southern Hemisphere. They determined an atmospheric temperature coefficient in the intensity of cosmic rays after an expedition of 32 months, which showed no major difference in both hemispheres. However, variation was found in warmer and colder months, with intensity being higher in the latter [5]. 

After graduation, Compton offered him a postgraduate fellowship, but he declined because he wanted to explore the azimuthal variation of cosmic ray strength in India. As a result, he was awarded a travelling research fellowship by the institution. Gill returned to India and became a physics lecturer at Forman Christan College, where he also established a cosmic research laboratory. He travelled to the Himalayas in 1945 to investigate the generation of mesons by the non-ionizing component of cosmic rays, but no mesons were found. These tests were repeated with RAF planes, and mesons were identified at altitudes of more than 20,000 feet [3]. The American government provided them with a B-29 bomber from World War II to conduct extensive observations of cosmic rays over the Pacific Ocean at an altitude of 33,000 feet, which confirmed his earlier Himalayan expedition results [2]. In Lahore, he published a detailed paper on the azimuthal influence of cosmic rays [3]. For the main cosmic radiation, he calculated a power law energy spectrum. Gill and Vaze detected E-W asymmetry in the energy spectrum of primary radiation in Bombay using a similar setup [3].

Sarojini Naidu introduced him to Miss Mrinalini Chattopadhaya, the principal of Ganga Ram Training College in Bombay. There, he met Chambeli, who would later become his wife in a marriage held on February 17, 1942. They had two daughters named Nishtha and Surishtha [2]. 

In 1947, he became a professor of experimental physics at the Tata Institute of Fundamental Research in Bombay, where he conducted high-altitude hydrogen balloon experiments. He returned to America a year later to work in the Department of Terrestrial Magnetism at the Carnegie Institution in Washington, D.C., where he examined the relationship between solar flares and unexpected surges in cosmic ray strengths with M. S. Vallarta and S. E. Forbush [3]. 

Pandit Jawahar Lal Nehru, India's Prime Minister, convinced Gill to accept a position as Professor and Head of the Physics Department at Aligarh Muslim University (AMU) on September 1, 1949, where he created well-equipped research laboratories. In April 1950, he was named Dean of the Faculty of Science. He examined cosmic ray absorption in the lead at Gulmarg (8890 ft.) and Srinagar, developing M (Geiger-Müller) counters, neutron counters, nuclear emulsion techniques, and advanced electronic circuits for experiments (5000 ft.). He also revolutionised nuclear physics, optical and vacuum spectroscopy, and radio-frequency spectroscopy, such as Nuclear Quadrupole Resonance (NQR), Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR), and microwave spectroscopy, by establishing state-of-the-art facilities. Under his supervision, SP Puri, RN Mathur, Yog Prakash, IS Mittra, AP Sharma, LV Sud, Ch. V Shastri, and A Bhaskar Rao are among the students who received PHDs in cosmic ray research [2]. 

He travelled to East Germany and the Soviet Union to visit scientific institutes. He taught at Washington State University in Pullman, Washington, as a visiting lecturer. In 1962 and 1963, Gill was invited by the American Institute of Physics and the American Physics Teachers' Association to give talks at various universities around the United States. He became the director of the Central Scientific Instruments Organisation in Chandigarh on September 2, 1963.He selected devoted young scientists and launched their careers in the development of new instruments in optics, electronics, environmental medical electronics and process control. After retiring, he wrote physics textbooks for high schools, which were translated by his student H.S. Virk into Punjabi and published by Rupa & Co., Delhi [7].

Awards and Honours 

Professor Gill held esteemed positions in various renowned universities and learning bodies throughout his career. He was a Research Fellow, University of Chicago, 1940-41; Lecturer in Physics, F.C.College, Lahore, 1940-47; Professor of Experimental Physics, Tata Institute of Fundamental Research, 1947-49; Officer-on Special Duty, Atomic Energy Commission, 1948-49; Professor and Head, Department of Physics, Aligarh Muslim University, Aligarh, 1949-63; Dean, Faculty of Science, Aligarh Muslim University, Aligarh, 1950-53 and 1956-58; Director Gulmarg Research Observatory, Gulmarg,1951-71; Honorary Professor of Physics:(i) Jammu & Kashmir University; (ii) Panjab University; Honorary Scientific Adviser to the Government of Panjab; Director, Central Scientific Instruments Organisation, Chandigarh, 1963-71; Emeritus Professor of Physics, Punjab Agricultural University, Ludhiana, 1971-81.

Membership of Societies

Fellow of the American Physical society; Fellow of the Indian Physical Society; Fellow of the National Academy of Sciences of India; Fellow of the Indian National Science Academy; President of the Physics Section of the Indian Science Congress, 1954;. President of the National Academy of Sciences of India, 1956-58; President of the Indian Physical Society; Secretary(outstation), Indian Science Congress Association, 1960-63; Foreign Secretary, Indian National Science Academy, 1961-64; Vice-President, Northern India Science Association; President, Optical Society of India, 1970[2]. 

Positions Held in Societies 

President of the Physics section of the Indian Science Congress (1954).

President of the National Academy of Sciences of India (1957–58).

President of the Indian Physical Society.

Secretary (Outstation) Indian Science Congress Association (1960–63).

Foreign Secretary, Indian National Science Academy (1961–64).

Vice-President, Northern Indian Science Association.

President, Optical Society of India (1970).

Membership of Bodies

Member of the U.P. Scientific Research Committee.

Member of the U.P. University Grants Committee.

Member of the Council of the Indian National Science Academy.

Member of the Council of Indian Physical Society.

Member of the Council of the National Academy of Sciences of India.

Member of the Board of Editors of the Indian Journal of Physics.

Member of the Faculties of the University of Lucknow, Banaras and Allahabad.

Member of the National Scientific Advisory Council of the Institute of Comprehensive Medicine and also the Editorial Board of the Int. Journal for Comprehensive Medicine, California.

Member, Panel of Consultants in Technological Sciences and Applied Research to the Director-General of UNESCO, 1967.

Chairman, Development Council for Instruments Industry set up by the Govt. of India, Ministry of Internal Trade and Company Affairs (Department of Industrial Development).

Member, Senate, Punjab University, Chandigarh.

Member, Senate, and Syndicate, Punjabi University, Patiala.

Member, Senate, Guru Nanak Dev University, Amritsar.[2]


In 1989, Professor Gill relocated to the United States to be closer to his kids and grandchildren. He gave his personal library of books and journals to the Panjab University Department of Physics' departmental library. He lived in Atlanta with his younger daughter, DR. Surishtha Shegal, a Georgia State University professor and director of the Carter Award Program, and his son-in-law, RK Sehgal, Georgia's Commissioner of Industry, Trade, and Tourism. While in Atlanta, he became an adjunct professor of physics at the Georgia Institute of Technology. He died of congestive heart failure on March 23, 2002 [2]. On that day, India lost one of the most valuable diamonds in physics. Many people still continue to benefit from his research-intensive career, and his legacy continues to inspire the masses.


  1. Piara SIngh Gill - Up Against Odds - Autobiography of An Indian Scientist (1992)
  2. SP Puri - Piara SIngh Gill
  3. Virk, Hardev Singh, Singh Rajinder - The Pioneers of Cosmic Ray Research in India (October, 2016)
  4. Piara Singh Gill - Further Study of Cosmic Rays on the Pacific Ocean (15 June, 1939)
  5. Piara SIngh Gill, A. H. Compton - Cosmic Rays on the Pacific Ocean (July- October, 1939)