Actually, we have moved on from where you are. According to S.B.R., we can have, at least in principle, an 'infinite' range of vision on the surface of the Earth, because it is flat and because air near the Earth's surface does not have an anomalous refraction index.
What I was referring to was, the upper regions of the atmolayer, somewhere between the Sun and the the surface of the Earth. The gas of the atmolayer is ionized over there and possibly participates in a swirling motion. This creates the strange refraction index that makes the light from celestial bodies to curve as going to a weird lens. This might leave the impression, for example, that the position of Polaris on the night sky is getting lower and lower as we approach the Equator, where, finally, it vanishes from view. In fact, one may define the Equator as the set of points on the surface of the Earth from which Polaris lies on the horizon. However, according to the above explanation this is purely an optical illusion effect, if you will.
Similar explanation holds for interchanging of day and night and Arctic periods of constant sunlight or darkness. Basically, you can think of it this way. If you look through a fish-eyed lens, you see the world distorted and curved. The ionosphere might cause a similar effect, causing us to see the 'heavens' as if we were on a RE.