Question 8. Why is the Moon larger when it is close to the horizon?

Although the Moon looks much larger when it is low in the sky near the horizon, this is actually just an optical illusion. It is actually the same size as when it is directly over head. This illusion has been known since ancient times and also happens with the Sun and the constellations. This same illusion works on mountains and tall buildings as well. They appear larger at long distances than they do at closer distances. The reasons for this are complex, but they have something to do with how our brains interpret the sizes of large objects on the horizon. If you don't believe this is only an illusion, you can compare the size of the Moon near the horizon to the size directly over head by holding your finger out at arm's length and comparing the sizes of the Moon with your finger.

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