A physicist born in Lahore, India, Chandrasekhar Subrahmanyan (1910-1995) helped predict the existence of the neutron star in the 1930s. He believed that when a supergiant star exhausted all the nuclear fuel in its core, the core would collapse under gravitational force. He also discovered the natural law, eventually coined the 'Chandrasekhar limit', that stated that if the mass of the core was 1.4 times the full mass of our sun (the basis of the measurement), when the star collapsed the positively charged protons and the negatively charged electrons would combine to form neutrally charged neutrons, resulting in a neutron star. If the core didn't reach the Chandrasekhar limit, a white dwarf would be formed. Click below to see an enlarged diagram.