Why does the moon seem larger when it's on the horizon than when it's higher up in the sky?

Answer 1

Actually, the sun and moon have very similar apparentdiameters, which makes total solar eclipses very rare. However, the moon is much smaller than the sun, but much closer to us. The sun is many thousands of times larger than the moon, but is millions of times farther away.

Answer 2

The so-called "moon illusion" has nothing to do with atmospheric distortion. The phenomenon can be observed with terrestrial objects, such as mountains or tall buildings (like the Empire State Building), which when viewed at long distances appear much larger than when viewed at closer distances. Here is a fact: the angle subtended by the moon's width when it is near the horizon is THE SAME as when it is directly overhead, even though it appears to be larger when low in the sky. One evening when the moon is low in the sky and appears large, hold your thumb up at arm's length and note the moon's size compared to your thumb. Later, when the moon is high in the sky, do the same thing. You will see that the moon's apparent size does not change. It's a somewhat disturbing experiment, since the data -- your thumb measurements -- defy what your eyes are telling you. Scientists are unsure what causes this phenomenon, but it is obviously related to how the brain interprets images of large, distant objects viewed low in the sky or that appear near the horizon. I observed this phenomenon myself when I visited Seattle for the first time. Mount Rainier, when viewed from Seattle, appears quite huge. It's a big mountain, no doubt, but it appears disproportionately large when viewed from Seattle. As you drive to the mountain, it looms quite large until you get into close proximity, when it doesn't seem quite as massive any longer. Anyone who has been to the New York City area has also observed this phenomenon when viewing the city's skyline from a distance, when the Empire State Building seems preposterously huge. But when the observer gets closer to the city -- say, right across the Hudson near the entrance to the Lincoln tunnel -- the ESB appears only somewhat taller than the other buildings and skyscrapers. answer It's a depth-perception glitch - your mind percieves it as being closer because you are viewing the moon and the relatively closer horizon in the same scope of vision. This is delightful. The moon looks larger at the horizon because it seems farther away. Yes, I know you think I stated that incorrectly. You will see how it works in a moment. Keep in mind the idea stated above of the angle subtended by moon being the same no matter where you see it. Now, when you see the full moon high in the sky, there is nothing readily visible to give you any cues about size or distance. It's just this beautiful white disk floating up there.

Now imagine how we interpret the size of images in our everyday experience. The angle sub-tended by the object is only a part of the picture. Try this "thought experiment". You are in the middle of Death Valley. Your best buddy is standing 100 yards away from you. Get an idea of the size of the image that your buddy makes on your retina. Now imagine a person standing 500 yards from you, but the person is producing the same size retinal imageas your buddy at 100 yards. You know this imaginary person is farther away because you can see that he is nearer to the horizon. The image is a little higher up, so you may even see it against the backdrop of distant mountains. You can see that this person will appear to you to be gigantic. And if he could actually exist, he WOULD be gigantic. But the retinal images for him and your buddy are the same. When we see the moon through trees, or above a horizon of mountains, we have a 'cue' to the distance on this image. The cues tell us: "That thing is far away. And consequently, the brain understands it to be-- Really big...

Answer 3

When the moon is nearer the horizon it is being observed through more atmosphere. The air acts as a magnifying glass and makes the moon appear much larger. As it rises higher in the sky, there is less air distortion and it appears a normal size. See the related question linked below. The atmosphere explanation is not generally held to play a major role in this illusion. Here's a link that explains it:

http://apod.NASA.gov/apod/ap031011.html

Answer 4

The moon appears larger because it has different phases. (new moon, waxing crescent moon, etc.)

Answer:

People often comment that he moon appears larger when it is near the horizon. This is an optical illusion - if you were to cut out a disc of paper the same size as the moon on the horizon and another when it is overhead, the disks would be the same size.

This happens because the moon on the horizon can be compared to objects you know are big - distant hills or mountains - and the moon seems bigger than them. Your mind translates this as "The moon is big!". When the moon is high in the sky there is nothing to compare it to, and the mind interprets this as being no particular size at all.

A variation on this explanation is that your mind knows the objects on the horizon are far away and are big (but look small) but the moon is "on the horizon" as well and looks big so that it must be even bigger than you thought. Again the high moon has no references and you can't judge size or distance.

Answer 5

When the moon is rising or setting, it is seen through much more atmosphere than

when it is overhead. Earth's atmosphere can act like a lens, and magnify it slightly.

Also, when the moon is near the horizon, you are seeing it with reference to trees

and other objects that may appear on your landscape, and it appears larger. When

you are looking straight up at a full moon, there are no other objects in your vision,

and you may not actually realize how large it appears.

i have a nice thoery about the moon mistary why it became bigger and smaller

but i kneed to explain it to scientific community, am sure every one will agree with

me 100 percent,

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Answer #2:

Earth's atmosphere does not 'act like a lens' and cannot magnify anything slightly.

In a photograph of the moon near the horizon and another photograph of the moon

near the zenith,the image of the moon is the same size on both photographs. The

explanation that includes the presence of reference objects is the correct one.

Answer 6

This is an optical illusion because near the horizon we have objects that are somewhat familiar to compare the Moon to. The Moon still only occupies about 32 seconds of arc as it does when it is high in the sky; but there is nothing in that direction to which we have a relationship so we can't compare it and the moon appears smaller.

Answer 7

Actually, it doesn't. If you photograph the sun and the moon and measure

the size of their images on the photo, you find that they're identical.

The sun's diameter is about 400 times the moon's diuameter, but it's about

400 times as far from us as the moon is. That lucky coincidence is the reason

we can have solar eclipses.

Answer 8

Because it's much closer to us than any of them is.

The distance from us to the moon is about 0.0026 of the distance to the sun,

and about 0.0000000096 of the distance to the next nearest star.

Answer 9

It's an optical illusion, the moon has the same size all the time. It looks bigger near the horizon because we see it compared to trees and buildings.