I have has this conversation a few times since I was little... there are actually a few factors which affect how far you can see. But since I only have a few minutes, I will try to keep it simple. Light curves around the edges of a sphere, in addition, atmospheric conditions can create a lense effect. If on the water, an shoreline 200 miles away, can be seen if there is enough humidity. Light reflecting off the water will reflect into the atmosphere making the waterline appear farther. The atmospheric lense effect makes the shoreline or city appear closer at the same time.
I have has this conversation a few times since I was little... there are actually a few factors which affect how far you can see. But since I only have a few minutes, I will try to keep it simple. Light curves around the edges of a sphere, in addition, atmospheric conditions can create a lense effect. If on the water, an shoreline 200 miles away, can be seen if there is enough humidity. Light reflecting off the water will reflect into the atmosphere making the waterline appear farther. The atmospheric lense effect makes the shoreline or city appear closer at the same time.