This question may have been asked a thousand times on here so please diredt me to the relevant post if that is the case. During a particle physics lecture I was told that although the fine structure constant is widely regarded as being 1/137 at normal lab energies, it seems to tend towards 1/128 at high energies. The lecturer refused to tell us why this occurred and even told us to ask other lecturers to watch them get uncomfortable. Anyway the best I got was look in Nature. Found out that there is evidence that it used to be lower in the past, but wondered if anybody could elaborate on which of the fundamental constants used to determine the fine structure constant varied at high energies.