Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

Why do you see half of the moon when you can see both the sun and the moon from earth at the same time on some days?

share|improve this question

closed as unclear what you're asking by Dilaton, Emilio Pisanty, Chris White, Waffle's Crazy Peanut, Qmechanic Aug 27 '13 at 7:13

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Are you sure its exactly half. I have seen thin crescents in the evening(4-5 pm) when the sun is high enough. –  udiboy1209 Aug 24 '13 at 12:32
    
possible duplicate of Why does the moon face earth with the same side? –  hwlau Aug 24 '13 at 17:16
add comment

1 Answer 1

enter image description here

You see, if you're standing at the south part of the earth in this picture you can only see half the moon, also called a crescent moon, because the part that you can not see is facing the oppsite direction of the sun, therefore not receiving any sunlight.

You don't always see exactly half, sometimes you only see a thin strip of the moon, google for "crescent moon" and you'll see what I mean.

share|improve this answer
    
out of scale, of course :-) –  Jan Dvorak Aug 24 '13 at 17:02
    
@JohnRennie The thing you said is simply not true; unless by day you mean at noon. –  Ali Aug 24 '13 at 17:16
    
@Ali: oops, yes, that was posted in excessive haste :-( –  John Rennie Aug 25 '13 at 10:15
add comment

Not the answer you're looking for? Browse other questions tagged or ask your own question.