how come the moon looks bigger on horizon then when it above you ?

Answer 1

It is an Optical Illusion related to how the brain perceives the Moon compared to Clouds. Clouds (and predators) overhead are quite close, while clouds (or predators) near the horizon can be many miles away. Your brain is hardwired to know this about the sky. The Moon, which is always the same size, seems larger when it is in a part of the sky where your brain knows things to be farther away and should appear smaller. I hope this helps. Good Moon watching!

Answer 2

As I understand it, appearances are deceiving. It is actually the same size. Use your thumb and hold it so it occludes the moon at the horizon and then later when overhead and you will see your thumb is at the same distance from your eye in both cases. If the moon changed size, the distance from your eye would be different. When I was a kid my dad demonstrated this with a coin and a yardstick and some modeling clay to hold the coin in place. We spaced the coin at the point where it was the exact size as the moon as it rose and then several hours later sighted again, which showed the same measurement..There is also another effect which can occur having to do with the atmosphere, acting like a lens in the same manner as a mirage is reflected so you can sometimes see things below the horizon, but this effect does not happen all of the time. Air is a fluid, and like glass will refract the light reflected from the moon. At the horizon, the light has to pass through much more atmosphere then when overhead which can also have a magnifying effect. Like the distance to the moon is not a constant, the depth of the atmosphere is not constant, which can change the refractive properties much like changing the curvature of a glass lens changes how it refracts light. The moon does change apparent size throughout the lunar cycle because the moon is not at a constant distance from the Earth. It really does appear larger when it is closer to the Earth then when it is further away. The same applies to the Sun since the Earth is in an eliptical orbit.

Answer 3

Objects on the horizon give away some of the moons real size.

Answer 4

This is the result of the frame of reference in which you are viewing the moon. At the angle that you see it with respect to the horizon as a reference frame, it appears larger.

Answer 5

Mostly its a matter of perspective. When its straight up its against a large blank field with nothing to give it an objective size. At the horizon its bracketed by objects of a known size to give your brain a size relation to it.

Answer 6

Partly optical illusion, but it is also magnified by the atmosphere. You are looking through twice as much atmosphere when you look at the horizon than you are when you look straight up.

Answer 7

It's a lensing effect, like when you look the bottom of a thick glass. the light bends shapes.