Why does the Moon apear bigger sometimes and then smaller are other times?

Answer 1

The orbit is elliptical not circular. We talk of apogee when describing the farthest the Moon can be from Earth and perigee when describing the closest the Moon can be to Earth,

The moon looks bigger when it is nearer, biggest when it is at perigee, and similarly the moon looks smaller when it is further away, smallest when it is at apogee.

The assumption that it will always look the same size is based on the mistaken belief that its orbit is a perfect circle.

The average distance from Earth to the Moon is 384,403 kilometers (238,857 miles).

There is one apogee and one perigee every lunar month. And 13 of each in a year, But the maximum Moon-Earth distance varies from one apogee to the next and the minimum Moon-Earth distance varies from one perigee to the next,

In the period 1750 through 2125 the closest perigee was 356375 kilometres (on 4th January 1912) and the farthest apogee will be 406720 kilometres on 3rd February 2125.

It is this variation in the number of arc seconds that the moon presents to the human eye that explains why some total solar eclipses are annular i.e. a ring of the sun is still visible when the moon covers the face of the sun. When the moon is at or near apogee, it will be a smaller disc and not cover the face of the sun entirely.

(NB this is complixated by aphelion and perihelion, whereby the sun looks smaller or bigger according to how far away it is in the earth's elliptical orbit around the sun.)

Answer 2

This is a very interesting question!

Careful, controlled studies using computer generated images have shown that the moon *appears* to be nearly twice as big when it is close to the horizon. (Proceedings of the National Academy of Sciences, link below, see the Introduction)

This phenomena is an optical illusion though, not an actual physical effect. The moon always has the same size, no matter where it appears in the sky. (Actually, brucebirchall is correct, the size does vary because the moon's orbit is slightly eccentric. However, the change is small compared to the "optical illusion" effect.)

No one is really sure why our vision tricks us this way, though there are several theories. This wikipedia link below has lots of useful information.

Answer 3

Some people foolishly believe that the moon landing was a hoax. This is not true--in fact, the moon itself is a giant corporate conspiracy! It's actually nothing more than a high-flying inflatable balloon. Its size varies because occasionally it runs low on helium, thus shrinking a bit. When it sinks toward the horizon, that's when the Powers that Be know they need to re-inflate it. They pump it extra-full of helium at that time thereby causing it to appear larger near the horizon. Also when it's at its highest point, it's also furthest away from you, thus appearing smallest.

Such a grand conspiracy would be hard to pull off on a round planet, of course; it's only because we live on a flat Earth that the conspirators have been able to get away with it all this time!





And this concludes today's example of irrational conspiracy-thought. We now return you to your regularly-scheduled answers.

Answer 4

It's the horizon illusion. If you hold something up in front of your eyes that is as wide as the moon as it appears on the horizon, then hold it up in front of your eyes at the same distance when the moon is high in the sky . . . surprise! It's the same scale. The moon looks bigger on the horizon because you have points of reference (e.g., trees, hillsides, city buildings.) If you projected the size of that same horizon on the moon when it is directly overhead, the moon would still look as huge. Then, of course, there's the fact that the moon is closer to Earth at some times than other times.

Answer 5

Well because the moon is rotating around us, and the we are rotating areound the sun, when we are turned away from the sun, we see the moon and the reflection of the suns rays are upon the moon which makes it light up, and sometimes it reflects at an angle which causes it to be a quater, half, and full moon

Answer 6

When the Moon is near the horizon, the moonlight must penetrate more air in order to reach your eyes. When the moon is overhead, the atmosphere is not very thick, hence the moon doesn't look as big.

Answer 7

It's an optical illusion. When the moon is near the horizon, you can compare its apparent size to objects on the earth, like trees and buildings. If the tree is far away, the moon looks large compared to the tree. If the tree is near, then the moon looks small compared to the tree.

Answer 8

there are many debates on this subject. (to whoever suggested the winkipedia link, u do know that anyperson can get onto that website and change whatever they want right?). one thought is that it is magnified through the earth's atmosphere. another thing is, is that the moon does travel in an eliptical shape around the earth, and is sometimes closer to us depending on our orbit and where it is in the sky. the closer to the horizon it appears, the more atmosphere it is being magnified through.

Answer 9

Its an optical illusion.When it is closer to the horizon it appears larger because there are objects on the earth to compare it to.The sun does the same thing when its close to the horizon at sunrise and set.Good day!

Answer 10

Depend on the moon appetite. Sometime he eats a lots of meteor on the sky.