I agree I read a little on things lately because I assumed I was seeing a bend of the horizon on top of a mountain I visited with a friend what I learned is depending on where one is standing on earth the time of day and the light reflection moving etc,, the light we can see doesn't pass through the earth it will bend around as it travels.
So this will picks up the sort of a invisible shape of things it passes and increases its affects on the eyes and how things appear like a object appearing bigger than it is or smaller than it is like ships on the sea seen from not that far off shore or on a smaller boat light bending including curvature of land.. Ever seen a carrier coming into port it's not until it's fairly close the size can be really seen.
even the horizon so the horizon can seem to bow and it is for real but it's just light is being curved so the visible affect can have a doubling affect of what it should appear one can be seeing more or less of a object. It's all alittle more science to it that but the basics I got from how light impacts human eye sight.