Satyendra Nath Bose (January 1, 1894 – February 4, 1974) was a physicist, specializing in mathematical physics. He is best known for his work on quantum mechanics in the early 1920s, providing the foundation for Bose-Einstein statistics and the theory of the Bose-Einstein condensate. He is honored as the namesake of the boson.

Satyendranath Bose's mother, Amodini Devi, had received little formal education but she skilfully brought up her large family of seven children. Bose's father was Surendranath Bose who worked for a while as an accountant before joining the East Indian Railways. He later set up his own chemical and pharmaceutical company. Satyendranath was the eldest of Amodini and Surendranath's seven children, having six younger sisters.

Satyendranath began his education at an elementary school in Calcutta before entering the Hindu School in 1907. It was here that his interest in mathematics and science began, and as is so often the case, it was due to an outstanding mathematics teacher coupled with encouragement from the headmaster.

He began his studies at Presidency College, Calcutta, in 1909 where he had a brilliant academic record. He was awarded a B.Sc. in 1913 and an M.Sc. in 1915 proving himself to be by far the best student of mathematics. In the year he was awarded his Master's degree, Bose married Ushabala Ghosh. They had five children, three daughters and two sons.

Had Indians been allowed to take administrative posts in the government service, Bose would almost certainly have followed that route. As it was, he continued to study physics and mathematics and was appointed to the newly opened University College of Science in Calcutta in 1917. This university was a research institution for postgraduate studies and here Bose was able to study recent European texts on quantum theory and relativity which, before the opening of the new institution, had not been readily available in India. Gibbs book on statistical mechanics stimulated Bose's interest in this topic. He also studied Einstein's papers on relativity and obtained Einstein's permission to translate them for publication in India.

Bose was appointed as a Reader in physics at the University of Dacca in 1921 and taught there until 1945, being a professor and head of the physics department from 1927. In 1945 he returned to Calcutta University when he was appointed as Guprasad Sing Professor of Physics, a position he held until he retired in 1956 when he was made Professor Emeritus.

He did important work in quantum theory, in particular on Planck's black body radiation law. Bose sent his paper Planck's Law and the Hypothesis of Light Quanta (1924) to Einstein. He wrote a covering letter saying:-

Respected Sir, I have ventured to send you the accompanying article for your perusal and opinion. You will see that I have tried to deduce the coefficient .. in Planck's law independent of classical electrodynamics.

This paper was only four pages long but it was highly significant. The derivation of Planck's formula had not been to Planck's satisfaction, and Einstein too was unhappy with it. Now Bose was able to derive the formula for radiation from Boltzmann's statistics. The paper, and his method of deriving Planck's radiation formula, was enthusiastically endorsed by Einstein who saw at once that Bose had removed a major objection against light quanta. The paper was translated into German by Einstein and submitted with a strong recommendation to the Zeitschrift für Physik. Einstein extended Bose's treatment to material particles whose number is conserved and published several papers on this extension.

An important consequence of Einstein's response to Bose's article was that his application to the University of Dacca for two years research leave beginning in 1924 was approved. He now had the chance of meeting European scientists and travelled first to Paris where he met Langevin and de Broglie. In October 1925 Bose travelled from Paris to Berlin where he met Einstein. Much progress had been made by Einstein following his receipt of Bose's paper for he was able to see how the ideas could be taken forward. While he was in Berlin Bose attended a course on quantum theory given by Born.

Bose published on statistical mechanics leading to the Einstein-Bose statistics. Dirac coined the term boson for particles obeying these statistics. Through these terms his name is rightly known and remembered, for indeed his contributions are remarkable, especially given the fact that he made his important discoveries working in isolation from the mainstream developments in Europe.

It was not only for his research contributions that Bose is important, however, for his efforts to improve education in India led to a much greater use of technology. He gave leadership in many ways: as president of the physics section of the Indian Science Congress in 1939, as general president of the Indian Science Congress in Delhi in 1944, and as president of the National Institute of Science of India in 1949. His greatest honour was election to the Royal Society of London in 1958.

After Bose retired from Calcutta University in 1956 he was appointed as vice-chancellor of Viswa-Bharati University, Santiniketan. Two years later he was honoured with the post of national professor.

While at the University of Dhaka, Bose wrote a short article called Planck's Law and the Hypothesis of Light Quanta, describing the photoelectric effect and based on a lecture he had given on the ultraviolet catastrophe. During this lecture, in which he had intended to show his students that theory predicted results not in accordance with experimental results, Bose made an embarrassing statistical error which gave a prediction that agreed with observations, a contradiction.

Since the coins are distinct, there are two outcomes which produce a head and a tail. The probability of two heads is one-fourth.

The error was a simple mistake that would appear obviously wrong to anyone with a basic understanding of statistics, and similar to arguing that flipping two fair coins will produce two heads one-third of the time. However, it produced correct results, and Bose realized it might not be a mistake at all. He for the first time held that the Maxwell-Boltzmann distribution would not be true for microscopic particles where fluctuations due to Heisenberg's uncertainty principle will be significant. Thus he stressed in the probability of finding particles in the phase space each having volumes h3 and discarding the distinct position and momentum of the particles.

Physics journals refused to publish Bose's paper. It was their contention that he had presented to them a simple mistake, and Bose's findings were ignored. Discouraged, he wrote to Albert Einstein, who immediately agreed with him. Physicists stopped laughing when Einstein sent Zeitschrift für Physik his own paper to accompany Bose's, which were published in 1924. Bose had earlier translated Einstein's theory of General Relativity from German to English. It is said that Bose had taken Albert Einstein as his Guru.