Why do moon looks different sizes on different days?

Answer 1

BY MOON PHASES

In order to reinforce your understanding of why the moon varies through its phases- try the following simple experiment. Stand in a darkened room with one very strong source of light (perhaps a spotlight) at the far end. Hold up a ball at arm's length to represent the moon. Let your eyes represent an attentive observer on the Earth, which is itself represented by your head. Now move the ball around in various ways, so that its orientation with respect to the source of light changes, just as the moon orbits the Earth while illuminated from one direction by the sun.

What happens? Well, at times you see the moon (ball) as a thin crescent [when it is held nearly in the direction of the lamp]; at other times, it resembles a full moon [when it is held on the side opposite to the lamp], and so on. So, too, as the moon orbits the Earth we observe it in various directions relative to the sun's location, and we see the lit-up side of the moon more or less fully depending upon the geometrical arrangement at the time. In short, despite what many people erroneously believe, the phases of the moon are not caused by the Earth's shadow falling upon it.

This correct understanding is not a modern development, by the way. Indeed, Lucretius, writing in the third century BC, said:

...it may be that it [the moon] shines only when the sun's rays fall upon it. Then day by day, as it moves away from the sun's orb, it turns more of its illuminated surface towards our view till in its rising it gazes down face to face upon the setting sun and beams with lustre at the full. Thereafter, it is bound to hide its light bit by bit as it glides round heaven towards the solar fire...
In other words, the ancients had a clear and correct understanding of the origin of the phases of the moon - and of the cause of eclipses too. (Indeed, there are historical records of the successful prediction of eclipses in the centuries before Christ, and many indications of a well-developed understanding.)

Answer 2

Hi. The Moon actually varies only slightly in size due to its orbit being elliptical. The size is just about half a degree. When you see the Moon way up in the sky you have nothing to compare it with EXCEPT the sky, which is large. So the Moon looks small. When you watch it rise or set and you see it against background houses or trees it look huge compared to them. Your mind makes the judgment that the Moon looks big.

Answer 3

The earth revolving around the sun, similarly the moon also revolving arond the earth so that the moon looks different sizes of different dayes.

Answer 4

It is an optical effect from the earths atmosphere. As the earth is round, so is the atmosphere. As the moon is lower in the sky you see it though more of a curved part of the atmosphere which effectively works like a giant magnifying glass.

When the moon is high in the sky you get almost nothing of the magnifying effect.

Answer 5

These are called the phases of the moon and have to do with the relative positions of the Earth, moon, and the sun.

A picture is worth a thousand words, so take a look at the animation at this website ==> http://jove.geol.niu.edu/faculty/stoddard/JAVA/moonphase.html

Answer 6

We can see the moon as the sunlight falls on it. Due to different orientations of sun, moon and earth in space everyday. Everyday sunlight falls on different regions of the moon. So the region which we see gets different sunlight on different days. So the shape of the moon which we see differs everyday.

Answer 7

Because you can only see the part that is illuminated by the sun which changes as the moon circles around the Earth.

Answer 8

It is looking different sizes because it is in relationship to the planet. the moon moves closer and then further away.

Answer 9

u can only c some parts of the moon at certain times b/c the sun has to illumionate the moon!!!

Answer 10

because earth is revolving around the sun, in a similar way moon is also revolving around earth. so we see that part of the moon which is illuminated by sun. although we see same face of moon always.