I live in Australia and when the moon isn’t full it always appears to fill up from the bottom up. So a new moon looks like a croissant with the curved side facing down. But on northern hemisphere flags like Turkey for example it appears as a croissant standing up with the curve facing left. Does the moon appear to wax and wane from top to bottom or left to right in different parts of the world?
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The flags aren’t realistic — in particular, the Turkish flag shows a star within the arms of the crescent which is obviously impossible .
Most of the top answers on this thread are complete nonsense too. The moon is far away from earth (about 100x it’s diameter), parallax effects are negligible and the analogies with a soccer ball don’t work if you actually do them to scale.
So, what’s happening? Well, the moon is lit by the sun. The closed side of the crescent ALWAYS points at the sun because you are seeing the part of the moon with sunlight shining on it .
If the sun is just below the horizon (be it sunrise or sunset, the closed side of the crescent points down and also a bit to the left or right
What varies based on latitude — AND season — is whether it’s a bit to the left or a bit to the right .
The sun always sets in a westerly direction, but in the southern hemisphere it goes E -N – W while the north goes E – S – W.
So if you look at a sunset in the southern hemisphere, the moon will be up and to the right of the sun , so the crescent points up and right; whereas in the northern hemisphere it will point up and left since the sun came from the left (south).
To put it another way, everyone’s looking at the same picture but the angle of horizon slopes the opposite way for each hemisphere . In your eye view you think of the horizon as constant and the bodies moving, but try thinking of the sky as constant and the horizon angle changing.
As mentioned earlier there is seasonal variation too — take a photo of every sunset over the course of a year and you will see the angle changing .
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