If the Earth is in the shape of a geoid, why does it appear almost like a perfect sphere in pictures?
A few days ago, photos taken by the astronauts of "Artemis II" were released. In these images, the Earth looks almost like a perfect sphere.
But if the Earth is in a geoid shape, why is this characteristic not reflected in the photos?
Does appearing spherical in the pictures mean the Earth is a perfect sphere?
Actually, no. This is due to the very small difference between a geoid and a sphere.
The Earth is slightly flattened at the poles. However, this flattening is not as large as we might think. The equatorial diameter is approximately 12,756 km, while the polar diameter is 12,714 km. The difference between them is just 42 km.
For such a large planet, a 42 km total difference corresponds to a very small, approximately 0.3% difference in size.
You can imagine it like this: if you place a hair strand on a football, the amount its smooth appearance changes is as much as the Earth would look different from space. That is, our eye cannot distinguish such a small difference.
Therefore, when viewed from space, the Earth appears almost as an ideal sphere.
It is physically impossible for the human eye to distinguish this small difference in a photo taken from thousands of kilometers away. Even if the Earth were the size of a billiard ball, the Himalayas or the Mariana Trench would be so small that they would not be noticeable.
The photos are not fake. Simply, reality itself shows the Earth as a sphere to our eyes. So saying "the Earth is a geoid" does not contradict it appearing visually spherical.
Shahbaz Mirzayev