Look out over the ocean. Why can you not see the land on the other side? There are no 'objects' in the way.
I'm really getting tired of copy/pasting this:
Q: If the earth is flat why can’t I see China from the coast of California?This is a common question poised by newcomers to the forums. According to the layman one should be able to see forever across the horizon in the perfectly transparent atmosphere.
Unfortunately this is pure fallacy. Atoms are not transparent. And thus, the atmosphere is not perfectly transparent. After a certain point into the distance air density becomes clouded to the point it completely obscures objects beyond it. Viewing distance into the horizon is directly correlated with pressure, gas constant, temperature, humidity, and pollution. At sea level the average air density is 1.2250 kg/m3. This sort of density will allow a viewing distance of around 30 miles across the horizon. In New York the pollution and humidity is so bat that viewing distance is limited to around 14 miles.
At higher altitudes the air density drops sharply, allowing the viewer to see far away lands before they are obscured by a blue-white sky. It is for this reason that an observer standing on Mt. Everest can see other mountains over a hundred miles away. Such pristine conditions are rare on the earth, however.
Q: If the air obscures objects past 30 miles, why can I still see the sun?Like headlights through fog the sun is intense enough to shine through the air’s density, illuminating the earth. Overhead, the sun is very intense. At the horizon the sun is considerably less intense since it must shine through more of the atmosphere at the horizon. Consider for a moment, is it easier to look at the sun at noon or at sunset?
The stars and moon are also less intense at the horizon than at zenith.