On this date 16th February) in 1956, India bid farewell to the great scientist and patriot Meghnad Saha who gave the world the path-breaking Thermal Ionisation Equation. Saha was born on October 6, 1893, in a humble Bengali family in a small village of Seoratali in Dacca district which, back then, was a part of the Bengal Presidency.
His early life
Meghnad Saha was born to a humble shopkeeper Jagannath Saha and Bhubaneshwari Devi. Saha was the fifth child out of their eight children. The family struggled to make ends meet due to which his siblings had to drop out of school. But seeing Saha’s interest his education, his elder brother arranged for his education. After completing primary school, Saha was facing difficulty continuing his education as the nearest secondary school was 10 km away from his house. Saha’s brother found a sponsor named Ananta Kumar Das for his education who funded his lodging and boarding expenses. Das was a doctor who agreed to keep Saha in his house on the condition that he would help in the housework.
Saha joined a city collegiate school in Dhaka in 1905 where his brother financially supported him. After clearing his intermediate exams in 1911, Saha joined the President College, Kolkata where he was taught by kinds of Prafulla Chandra Ray and Jagadish Chandra Bose. After graduating in Mathematics, he completed his master’s in Applied Mathematics from Calcutta University in 1915.
His career
Meghnad Saha started his career by joining as a lecturer in the Department of Applied Mathematics in the Calcutta University College of Science in 1916. He joined the physics department later but struggled to get his papers published in journals due to the insufficient budget of the college.
Fortunately, in 1919, Saha received the Premchand Roychand Scholarship for his dissertation in the ‘Harvard Classification of Stellar Spectra’. With the scholarship, he was able to stay in Europe for two years which allowed him to work in labs of scientists like Alfred Fowler and Walter Nernst.
After returning to India, Meghnad Saha joined Allahabad University as a professor in 1923 and taught there till 1938. In 1927, he became a Fellow of the Royal Society in 1927. He also presided the 21st session of the Indian Science Congress in 1934. Subsequently, he joined the University of Calcutta and became Dean of the Faculty of Science. He taught there till his death in 1956.
In 1916, under the visionary leadership of Vice-Chancellor Sir Ashutosh Mukherjee, the University of Calcutta appointed Meghnad Saha and his classmate Satyendra Nath Bose as lecturers in the Department of Mathematics. Both had been students of the eminent scientist Sir Jagadish Chandra Bose.
His revolutionary Thermal Ionisation Equation
In 1920, Meghnad Saha made a revolutionary contribution to the world of astrophysics by formulating the Thermal Ionisation Equation also known as ‘Saha Equation’ which was later perfected by the British astrophysicist Edward A. Milne. The Thermal Ionisation Equation is a mathematical equation that explains the relation of the ionisation of a gas with its temperature and pressure. It shows how the Ionisation of a gas changes as it approaches thermal equilibrium.
The equation is applied in astrophysics to classify the stars and study their spectrum. Since the equation links the composition and appearance of the spectrum with the temperature of the light source, it helps in determining the characteristics of the chemical composition of light like a star and also in determining its temperature.
His thesis on the ‘Origin of Lines in Stellar Spectra’ won him the Griffith Prize of Calcutta University.
His other contributions
Meghnad Saha took several initiatives to promote academics in India. Saha was responsible for designing India’s first ever nuclear physics syllabus in MSc. in 1940. He also built a a cyclotron which was a first in the country. He was instrumental in the establishment of the Indian Science News Association in 1935 and the Insitute of Nuclear Physics in 1950.
In 1952, Saha successfully contested Parliamentary elections as an independent candidate from the North-West Calcutta constituency. As an MP, he ensured that the Saka Calender is adopted as the national calender in 1956.
