> Ismail Abu al-Fida’s 1323 hypothesis regarding a “circumnavigator’s paradox,” which held that exactly one day would be inevitably lost by long-distance travel

> Ismail Abu al-Fida’s 1323 hypothesis regarding a “circumnavigator’s paradox,” which held that exactly one day would be inevitably lost by long-distance travelers “bearing the Sun company.” I had never quite thought about it like this, but of course it makes sense. It seems like it's the same as, but kind of the opposite of, the coin rotation paradox, or the fact that there are 366.25 sidereal days in a year.