Why Does the Moon Look Big on the Horizon?

The Moon, which lightens our planet at night, might appear larger or smaller to our eyes from time to time, depending on its location. Why does the moon appear from our world in different shapes? It would be wrong to say that it takes different shapes, its size or speed doesn’t change when we see it. For this reason, it’s thought that some illusions cause this problem. Now let's look at them together.

When looking at horizon views, both in the movie industry and in normal life, the Moon appears larger than when it is on the top. For example, consider a straight road with trees of the same height on both sides. As you look ahead of this road, you will see that it narrows and the trees get smaller. But in fact, you know that these trees are the same height, and as you get closer to them, this small appearance will disappear. This is called the Ponzo illusion.

An illusion put forward by the German psychologist Hermann Ebbinghaus is that when two objects of the same size are placed around them, objects of different sizes appear as if there is a difference in size between these two initially identical objects. We can say that this situation, which you can understand from the image below, is about how we store the objects in our memory.

We know that skyscrapers and tall buildings are 'big' in our brains. When we look at these structures from a distance, we know that although they may seem small, we know that they are actually large, and the Moon standing behind them and appearing larger than themselves, therefore, appears to be larger on the horizon than when it is in the sky.


Alpartun Günhan