why does full moon look bigger on the horizon than it does overhead?

Answer 1

optical illusions.


#1 you can judge the size of the moon to objects on the horizon. theres nothing to compare it to high in the sky so it looks smaller

#2 you are looking INTO the LONGEST portion of the atmosphere on the horizon.... it has the tendancy to magnify objects.
when the moon is straight up in the sky you are looking through the SMALLEST portion of the atmosphere.

If you believe #2 you should understand that the moon should actually look SMALLER
so it CANNOT be true,

http://www.howstuffworks.com/question491.htm

Answer 2

This question actually has not been fully answered. The moon is actually relatively the same distance on the horizon and overhead, and some think it has to do with the way the brain interprets data. Like if it is near the horizon, it is near other thing in the foreground, like houses, trees, and landscapes. And when it is overhead it is not, so maybe it looks "closer" on the horizon.

Answer 3

It is an optical illusion. To prove it, hold up a dime at arms length and compare it to the size of the moon when it is near the horizon, then when it is overhead. You will see that the relative size will remain the same; it is the lack of reference that is creating the illusion that it is bigger or smaller.

Answer 4

Our brain believes the sky near the horizon is further away from us than the sky overhead, mostly because that is how it appears due to clouds. As such, for the moon to have the same apparant size as it does on the horizon, but be what our brain thinks is further away, it seems as if it is bigger (because if it was further away it would have to be larger to appear that size). Basically it looks larger than your brain thinks it should.

Answer 5

It's been shown that it is not the comparison with objects on the ground. It's also easy for ANYONE to show that it isn't the atmosphere that increases its size in the sky, because its size doesn't increase in the sky. You can see that yourself by comparing it to a small coin when it's low and high in the sky.

This is the best explanation offered so far:

http://facstaff.uww.edu/mccreadd/

Answer 6

The moon appears bigger on the horizon because its light must pass thru more of the atmosphere to reach your eye than when it is over head. The net effect is one of magnification.

Answer 7

It's an optic allusion.