Meghnad Saha (6 October 1893 – 16 February 1956) was an Indian astrophysicist who helped devise the theory of thermal ionisation.

His Saha ionisation equation allowed astronomers to accurately relate the spectral classes of stars to their actual temperatures.

[1][2][3] Meghnad Saha was born on 6 October 1893 to a low-caste Bengali Hindu family in the village of Sheoratali in Gazipur, then part of the Dacca district of the Bengal Presidency (now Bangladesh.

[6] Due to the superstitious religious ideologies of the orthodox haughty Brahmins of the time and his childhood and career experiences of casteism, Saha developed a hatred for Hinduism from a young age.

Saha had previously reached the following conclusion on the subject: It will be admitted from what has gone before that the temperature plays the leading role in determining the nature of the stellar spectrum.

Too much importance must not be attached to the figures given, for the theory is only a first attempt for quantitatively estimating the physical processes taking place at high temperature.

We have practically no laboratory data to guide us, but the stellar spectra may be regarded as unfolding to us, in an unbroken sequence, the physical processes succeeding each other as the temperature is continually varied from 3000 K to 40,000 K.[14]Saha also invented an instrument to measure the weight and pressure of solar rays.

Due to low funding for his campaign, Saha wrote to the publisher of his textbook Treatise on Heat to ask for an advance of ₹5000.

Saha participated in the areas of education, refugees, rehabilitation, atomic energy, multipurpose river projects, flood control, and long term planning.

But the reason why he was slowly drifting towards this public role (he was never a politician in the correct sense of the term) was the gradually widening gulf between his dream and the reality—between his vision of an industrialised India and the Government implementation of the plan.