On Mon, 01 Jun 2009 00:09:59 -0700, Hello China Blue Sky Hello
If you'd finish reading what I quoted, you'd see it said just that.
Post by Hello China Blue Sky HelloThe moon is closer to Earth at moonrise and moonset. That it is why
the moon on the horizon is larger than the moon overhead.
Ummm, no.
-------
Explanation: Is the Moon larger when near the horizon? No -- as shown
above, the Moon appears to be very nearly the same size no matter its
location on the sky. Oddly, the cause or causes for the common Moon
Illusion are still being debated. Two leading explanations both hinge
on the illusion that foreground objects make a horizon Moon seem
farther in the distance. The historically most popular explanation
then holds that the mind interprets more distant objects as wider,
while a more recent explanation adds that the distance illusion may
actually make the eye focus differently. Either way, the angular
diameter of the Moon is always about 0.5 degrees. In the above
time-lapse sequence taken near the end of 2001, the Moon was briefly
re-imaged every 2.5 minutes, with the last exposure of longer duration
to bring up a magnificent panorama of the city of Seattle.
http://apod.nasa.gov/apod/ap031011.html
------------
Or, if you prefer:
Q: Why does the moon appear to be bigger on the horizon than in the
sky?
A: 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.
http://wiki.answers.com/Q/Why_does_the_moon_appear_to_be_bigger_on_the_horizon_than_in_the_sky
---------------