The perception that the horizon remains at eye level regardless of altitude or distance is a common phenomenon reported by pilots and observers, but it can be explained by the curvature of the Earth. Here's an explanation of why this perception occurs:
Scale and Perspective: The Earth is very large compared to our everyday experiences. When we are at ground level, the curvature of the Earth is not readily noticeable due to the scale of our surroundings. The horizon appears relatively flat, and it seems to be at eye level because of our limited perspective.
Curvature of the Earth: In reality, as you ascend in altitude, the horizon does drop and follows the curvature of the Earth. However, the curvature is gradual over large distances, and our eyes have limitations in perceiving small changes in curvature. This means that the drop in the horizon is not immediately noticeable to the human eye.
Visual Illusion: The perception of the horizon at eye level can also be influenced by visual illusions. When there are no reference points in the surrounding landscape or sky, it can be challenging to discern the true position of the horizon. Our brain tends to align the visual horizon with our eye level, creating an illusion that the horizon remains at eye level.
It's important to note that even though the horizon may appear at eye level, the fact that it does not drop as we ascend is not evidence against the Earth's curvature. Extensive scientific evidence, such as photographs from space, satellite imagery, and the measurements of Earth's circumference, consistently demonstrate the Earth's spherical shape and its curvature.
In summary, the perception that the horizon remains at eye level is a result of the Earth's large scale, limited human perception, and visual illusions. However, these perceptual experiences do not contradict the well-established scientific understanding of the Earth's curvature.