Why are the stars as they are?

Eddington's parable revisited

Abstract

We revisit the famous Eddington's parable on the existence of the stars published in 1926, well before the nuclear sources of energy in stellar interiors were known. The moral of the parable, namely that the stars can exist only in a limited range of masses, is discussed in the light of Chandrasekhar's theorem enunciated in 1936, that treats the argument in a more rigorous way, but leaving unaltered the Eddington's conclusions. It emerges that the existence of the stars cannot be attributed to the case but to a unique combination of the constants of nature involving special and general relativity, quantum mechanics and atomic physics.