Letter to The National Geographic

[chrisgreaves]

I refer to the web page at National geographic
Where I read "People in Asia saw the smile while sky-watchers in the United States saw a frown, though we're sure it was nothing personal."
I hope that you can correct this and future renditions of text, on the web or in print.

Below I have outlined some thoughts - I'm not the world's best writer - around my contention that a crescent moon must ALWAYS be an upturned arc, never a down-turned arc, and hence never a frowny-face.
A copy of The West Australian mentioned a frown-face, but search as you will you'll not find a photo of the December First event showing anything but a smiley-face.

* Thought Experiment #1: Imagine that you are in Toronto, facing West at sundown. Easy enough to do.

A crescent moon hangs in the sky.
Most of the moon is dark, but a sliver of crescent reflects light from the sun.
It follows that the sliver of crescent, the lighted bit, must be towards the sun.
And hence the dark bit must be away from the sun.
It also follows that the sharp points of the crescent must be pointing away from the sun, since they are, by definition, the extreme limit of the bright sliver which is, by definition on the side closest to the sun.

Nothing magic or complex here. You've seen it often enough before, and you can visualize it even if you close your eyes.

The sharp pointy bits can never point towards the earth; they must always point away from the sun.
And since the sun is "down there below the skyline", the pointy bits must be pointing "up there".
In other words, a smile; suitable for a Smiley Face.



* Thought Experiment #2: Imagine that you are in Toronto, facing East at sunup. Easy enough to do.

As for Thought Experiment #1



* Thought Experiment #3: Imagine that you are in Perth, Western Australia, facing West at sundown.

As for Thought Experiment #1



* Thought Experiment #4: Imagine that you are in Perth, Western Australia, facing East at sunup.

As for Thought Experiment #1



In short, a crescent moon must always be a smile.
It can never be a frown.

[bigaldoc]

? <post:=746,139>post 746,139</post:> ?

[pi-eater]

You are right that the points of the crescent must point away from the sun (up or on a slant up). I think that the confusion comes from the fact that it is not mentioned that the frown was upside down. I remember seeing the frown, but not the smile. At my latitude it was sort of on its side, but also upside down. The points of the crescent pointed diagonally down towards the southwest where the sun had set. Above, and to the left were Jupiter and Venus, the eyes. So if I turned my head on its side, I could see a frown.
Like most in the Western Hemisphere, I did not get a good look at the smile. The smile occurred before the frown. The smile was when the moon was to the right of Venus and Jupiter, so that the points of the mouth (crescent) pointed towards the eyes (Jupiter and Venus). Over the better part of a day, the moon moved from the right of the two planets, going directly between the two, and ended up to the upper left. So the smiling mouth moved up between the eyes and kept going to make an upside down frown. The pictures of the smile were all taken from the Eastern Hemisphere because the moon moves fairly fast through the stars and it was daylight in the West where I live when it was a good smile. I didn't get to see it until it was a frown.
I checked it all out on a neat little <img src=/S/free.gif border=0 alt=free width=30 height=15> program called Stellarium. According to it, the best places to see the smile were the Eastern Hemisphere. To have the smile straight up, you would want to be close to the equator, like the National Geographic photo.

<pre> . . . |
) ) ) |
. . . |
Smile ? Frown |
</pre>

[chrisgreaves]

<P ID="edit" class=small>(Edited by chrisgreaves on 29-Dec-08 11:20. Added dec 31st image)</P>>it is not mentioned that the frown was upside down
Thank you.
The various articles now make sense.

>Over the better part of a day, the moon moved from the right of the two planets, going directly between the two, and ended up to the upper left.
I can see this too, in my mind. The same must have happened here in Toronto on December 2nd, the day-after, excepting that, as for December first, we were clouded over.

I will take a look at Stellarium, thanks, and am looking forward to December 31st with keen anticipation. If it clouds over again I shall be keening.

(later) Cool!