Our universe is expanding: the distances between remote galaxies are increasing in a systematic way over time. But what about the galaxies themselves, planets, us humans or atoms, for example? If expansion is a universal phenomenon, are we expanding too? How easy it is to arrive at the answer (“no”) depends not least on how one interprets cosmic expansion: as the “expansion of space itself” (in which case what is happening is more difficult to explain) or as the movement of galaxies through space (in which case it is easier to understand).
