[philman_36]

Consider basic geometry.

When you're on a mountain do you look down to the horizon
or does the horizon come up to eye level?

YOU consider basic geometry

[marktwain]

When you're on a mountain do you look down to the horizon or does the horizon come up to eye level?

Neither. If the air is clear enough, the horizon expands, that is, the horizon moves away from you, if you are not impeded by terrain, say, with a mountain near an ocean. The higher you are, the further away the horizon is, limited by terrain.

Here is a simple geometric example of the phenomena.