Question

The compelling perceptual illusion known as the moon illusion involves a misperception that the moon is:

a) Smaller when near the horizon
b) Larger when near the horizon
c) Brighter when near the horizon
d) Always the same size in the sky

Answer 1

The 'moon illusion' makes the moon seem larger when it is near the horizon due to perceptual factors, even though the moon's actual angular size does not change and remains about 1/2° in our sky.

Step-by-step explanation:

The student's question refers to the moon illusion, which is a perceptual phenomenon. The correct answer to the question is that the moon appears larger when near the horizon. This is despite the fact that, as explained in our reference information, the angular sizes of the sun and moon remain around 1/2°, which means they appear about the same size in the sky. The moon illusion is not due to any physical enlargements but rather to a trick of our perception when the moon is compared to objects on the horizon, making it appear larger even though its angular size remains constant.

Various theories try to explain this illusion, ranging from the way our brains process visual information to the presence of visual cues in our surroundings. Notably, the moon illusion does not affect the moon's luminosity or its physical size; it only affects our perceived size of the moon. This topic is an interesting blend of physics and psychology, revealing how our perception can differ from reality.