If the moon is not full, what is shading it?

Question

and how does the crescent shape form and not just a half-circle?

Answer 1

the moon shades itself.

Take a soccer ball or a basket ball (preferably something with light colors: you'll see the phenomenon better) and a flashlight.

Get in the basement (or wait for the night...) and turn off all the lights. Direct your flashligh at the ball (aka the moon) and watch the ball from different anlges: you will see a "full-ball" (full moon) if you place yourself next to the flashlight, half a ball if you place yourself at a 90° angle from the ball-moon, and a crescent ball if you place youself somewhat between "right angle" and "right behind' the ball.


Try it out sometimes, you'll see it works. And the only thing casting a shadow here is your ball-moon


And it creates a crescent shape because the moon has (approximately) the shape of a ball...



As for earth's shadow, it only falls on the moon a few times a year (twice exactly. Once around each equinox). See "lunar eclipse" article on wikipedia. this is what the moon looks like when the earth's shadow is projected on the moon: http://en.wikipedia.org/wiki/Image:Lunareclipses2003.jpg (and yes, the colors are exactly those you see on those pictures...)
The redish color comes from the sunlight passing through earth's atmosphere: it acts like some sort of lens and redicts some sunlight to the moon. However, diferent colors don't react the same way to that lens, and only red wavelength make it to the moon, on these occasions.

Answer 2

NO NO NO, don't listen to these people who say the earth's shadow cause the phases of the moon. That's only in the case of a lunar eclipse (which can only happen on the night of a full moon when the sun, earth, and moon are perfectly lined up). If you see the right half moon illuminated, that's because the sun is shining from the right side.

Stand in a dark room and shine a flashlight at a baseball from the side and you will see. Damn, don't you people know anything about astronomy?? There's so many wrong answers for this question!

Answer 3

I must admit to being a bit stunned at some of these answers. Then my girlfriend, who is reading this over my shoulder admitted that she doesn't know either, so maybe it isn't as apparent as those of us with degrees in astronomy think. :)

The moon goes through its phases based on its position with us and also with the sun. As the moon passes between us and the sun during a new moon, the side we see is the unlit side. The far side of the moon (as Pink Floyd well knows) is the side facing the sun and is lit at that time, but we can't see it because it is facing away from us.
As the moon progresses in its orbit, it moves out from between us and the sun and starts to move off to one side. As it gets closer and closer to being beside us, we see more and more of the side that is lighted. When the moon is to one side of the earth or the other side, then we see half of the moon lit and half unlit. We see the first quarter phase or the "half moon".
The moon continues around the earth until finally it passes behind the earth. Sometimes it will pass through the earth's shadow and that is when we have a lunar eclipse. But when it does not pass through the earth's shadow, then we have a full moon. We see all of the side facing us because the sun is behind us and illuminating all of the side facing us.
Then the moon moves on around and goes through another quarter or "half moon" phase before returning to it's new moon phase.

It is during the new moon phase that the shadow of the moon can sometimes hit the earth and that is when we have a solar eclipse.

One other interesting occurrance can be seen for a few days just after the new moon or just before the new moon. You can actually "see" the part of the moon that is not lighted by the sun! This is called "earthshine" and is actually the sunlight being reflected from the oceans of the earth and dimly lighting the dark part of the moon just enough that we can see it.

Answer 4

If it was the earth that shaded the moon, then the moon could not orbit around the earth. It would have to stay in one spot relative to our rotation. The moon phases are caused by the angle the sun hits the moon in relation to the position we see it from. Also, FYI, we have never seen the "dark side of the moon". The moons rotation is exactly 1 earth day long, so even though the moon rotates, we will never see the other side.

Answer 5

The Earth. It casts a crescent shaped shadow on the surface of the moon because the Earth is between the sun and the moon and it is also spherical in shape.

Answer 6

the moon is illuminated by the sun. It will always be illuminated from its "north pole" to Its south pole' and thus depending on which angle the sun is will only ever be crescent through to full. The sun and earth and moom will be at right angles to each other to create the half full moon. The earth will be directly between the noon and sun ( although at a slight angle above the horizon) to create the full.

Answer 7

what a sorry state of affairs,

18 answers before this one
7 people have variants of the right answer
10 dumbos say the earth is shading the moon
1 person give no answer

the moon is shading itself from the sun, there are times when the earth is shading the moon from the sun's light, those times are called lunar eclipses

Answer 8

The Earth's shadow. Crescent shape is formed because the Earth is spherical in shape.

Answer 9

the face of the moon we see is the portion of light reflected from it. Try doing this activity.:

Take a globe.
put out the lights in the room in which you are performing this activity.
take your table lamp.
put it on

then revovle the Globe round your face.
At different Points you will See a face of the moon

By this Experiment we can see the phases of the moon
Thus we see that the shadow portions are only the parts which dont receive light from the sun i.e it is night there

Answer 10

Basically, nothing is "shading" it. What you see as black is really the part of the moon not facing the sun. Here's an excellent website that illustrates how the Moon's motion around the Earth gives the appearance of the lunar phases: http://www.astro.uiuc.edu/projects/data/MoonPhases/index.html