The perception that the Earth appears flat is primarily a result of our limited human scale and the vast size of the Earth. When we observe the Earth from our everyday perspective, such as standing on the ground or looking out at a landscape, the curvature of the Earth is not readily apparent due to its large size.
Here are a few factors that contribute to the Earth appearing flat from our everyday experience:
Localized observations: In our immediate surroundings, such as on a small patch of land or near a body of water, the curvature of the Earth is relatively negligible. The surface of the Earth within a small area appears flat to us because the curvature is only noticeable over much larger distances.
Limited field of view: Our field of view is limited to a few kilometers or miles in most cases. Over such short distances, the Earth's curvature is not easily discernible. We cannot see the entire Earth from our vantage point, so it appears flat within our visual range.
Lack of reference points: In our day-to-day lives, we often lack distant reference points that would help us perceive the Earth's curvature. When we look at the horizon, it appears level and unbroken, contributing to the impression of a flat surface.
Absence of noticeable vertical curvature: While the Earth is a spheroid, the vertical curvature (along the line from our feet to the sky) is much more subtle than the horizontal curvature (along the line of the horizon). This further reinforces the perception of a flat surface.
It is important to note that scientific evidence overwhelmingly supports the understanding that the Earth is an oblate spheroid, meaning it is mostly spherical but slightly flattened at the poles and bulging at the equator. This knowledge is based on extensive observations, measurements, satellite imagery, and other scientific data that confirm the Earth's curvature.