View attachment 26487
Here is a fish in water that we know is not where we actually see it from outside of the water.
But if we are in the water we will see the fish exactly where it is.
A city refracted over a curved earth is "not" at all like seeing a fish (or straw) that is in water from outside of the water.
We are not seeing the city through an atmosphere that we are outside of either. We are simply not seeing the city because it's behind a wall of water, no different than trying to see through a brick wall.
If the earth were curved the only way we could see the city skyline hidden behind and below it would be if there was a "reflection" of it, and above it, aka, a superior mirage.
Even if the cityscape was a refraction, we would have to believe that the same atmospheric conditions that produce the refraction could also at the same time, and in the same place, produce a superior mirage, which is not possible.
Again, the existence of an upside down superior mirage over the right side up cityscape of Chicago from 50 miles away over lake Michigan proves the right side up image is not a mirage or a refraction of the city, but is the actual city located exactly where we see it.
--Dave
This misses the point, Dave. The refractive index of water is the refractive index of water, whether you're in it or not. The transition from water to air and vice versa exaggerates the effect but that doesn't mean that light isn't refracted just because you're in the water with the fish. It is refracted, just not as dramatically. Light is refracted because of variations in density. Liquid water, being mostly uncompressible, has only very slight changes in density from one area to the next and so mirages can't really happen underwater. Air, on the other hand, being a gas, can vary greatly in density over relatively short distances and thus have a significantly greater refraction index in one place than in another. When light moves from an area of higher density to an area of lower density or vise versa the effect is most prominent just like when light goes from water to air, effectively placing you outside the fish bowl.
No time to edit that! Hope it makes sense!