The primary reason we can't readily see the Earth's curvature is due to its vast size relative to our perspective. The curve is subtle and gradual, making it difficult to perceive from ground level, especially over short distances. It becomes noticeable at higher altitudes, such as from airplanes or space, where the curvature spans a larger portion of our field of view, according to Instagram user The Engineer's Mess. The Earth is enormous, with a circumference of approximately 40,075 kilometers

Many people are surprised to learn that you can’t see the Earth’s curvature with the naked eye from the ground—or even from a typical airplane. That’s because Earth is enormous, with a circumference of about 40,000 kilometers, making its curve incredibly gradual. To the human eye, the horizon looks flat simply because the scale is far beyond our everyday perception. At sea level, the horizon is only about 5 kilometers away, and even at cruising altitude (around 10,000 meters), the curvature is s