same if you go on land. for instance, suppose there is a long, clear road, with telegraph poles the same distance from each other. you look at the one nearest to you, and you will find it high, but the next one looks lower and the next one still lower, and so they seem to be growing shorter and shorter until you cannot see them at all.
but it is not true that the poles are lower, as they look; it is only the distance that makes them seen so just like masts of the ship on the water. this may also apply to the sky.
the sun is the same way.
when 