LAUSR

We take it for granted that the Sun is powered by nuclear energy. We accept the fact by subconsciously using one of the epistemic tools1 available to us called authority. We believe it because the authority or expert, whose words are gold, says so; but it has not always been like that. Back in the mid-nineteenth century, everyone battled everyone else in the fight of ‘who is right’ about how the Sun shines. Physicists and astronomers were not the only interested parties in finding out the answer to the ‘how the Sun produces its energy’ question; geologists and biologists were curious, too. While the former group of scientists wanted to know its source, the latter were more concerned with the effects of the Sun’s energy on geological changes and evolution of life on Earth. As a result, many attempts had been made by prominent people like Hermann von Helmholtz and William Thomson (better known as Lord Kelvin), to name just two, to explain the nature of sunshine. But it took the genius of Arthur Eddington, from the work of F. W. Aston (Nobel Prize in Chemistry 1922), to solve the conundrum. In a totally unrelated experiment, Aston discovered that the mass of one helium atom is less than that of four hydrogen put together. Eddington recognised right away the significance of Aston’s result and noted that since mass must be conserved, the loss must be attributed to some energy being released. (Recall the famous E = mc2 equation.) In his presidential address at the British Association for the Advancement of Science in 1920 [1], Eddington remarked that: