For thousands of years, one scientific puzzle has fascinated and perplexed the greatest philosophers, mathematicians, physicists, and psychologists: why do the moon and sun appear so much larger on the horizon than when high up in the sky? This book provides a compelling account of this fascinating illusion. Taking us through the history, the characters involved, the attempts made to explain the illusion, through to modern day studies of visual perception, the book offers a comprehensive account of this mystery. The history of the moon illusion to a large extent reflects the history of theorie ... More

For thousands of years, one scientific puzzle has fascinated and perplexed the greatest philosophers, mathematicians, physicists, and psychologists: why do the moon and sun appear so much larger on the horizon than when high up in the sky? This book provides a compelling account of this fascinating illusion. Taking us through the history, the characters involved, the attempts made to explain the illusion, through to modern day studies of visual perception, the book offers a comprehensive account of this mystery. The history of the moon illusion to a large extent reflects the history of theories of size perception. A similar illusion can be observed for the sun, and it is normally called the sun illusion. This illusion is less well known to most people than the moon illusion, perhaps because the sun is usually too bright to observe with the naked eye. However, the sun illusion was more frequently discussed than the moon illusion in the early literature. Although two different celestial bodies are involved, there seems to be no fundamental difference between the two illusions: they are therefore generally considered to be two examples of the same phenomenon. A third example is the apparent enlargement of the constellations and of the distances between the stars near the horizon. This form of illusion is probably the least observed of the three, since fewer people give serious attention to the night sky. All three examples are generally known as celestial illusions.