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 of the
Moon taken in 2007,
with one exposure taken to bring up the foreground of
Izmit Bay in
Turkey.
On the occasion of our 14th anniversary, the
APOD editors thank all of our contributors and mirror site operators whose volunteer efforts help
bring the wonders of
astronomy to millions of people around the world.
Additional thanks also go to our
Turkish mirror site operators for submitting the above mouseover image.
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