The Moon (Part 2)

Abu Loren wrote: I agree with those who say that we only see one side of the Moon, and I believe that no matter where you are on the Earth one will see the same Moon meaning that the features of the Moon will be the same wherever you are on the Earth.

That's not what I meant.  Of course we only see one side (one hemisphere) of the moon, no matter where we are on the planet.  What I mean is that the side that we see (the "face" of the moon) appears to be rotated in the high latitudes, as compared with how it appears near the equator.

However, interestingly as you've alluded to I also think that as the latitudes increase and decrease meaning once you go north or south from the 'equator' the face of the Moon changes. You will look at the moon at an angle and will see differences on the face of the Moon. I wonder if this is the case with this phenomenon?

Exactly.  It's not actually the moon that is rotated -- rather, the observer is rotated as he travels away from the equator along the curved surface of the earth.  In fact, we could measure the curvature of the earth by noting the amount by which the image of the setting moon is rotated, compared to what it looks like at the equator.  The degree of rotation would equal the degree of latitude above or below the equator.

Cool!  You've discovered another way of proving that the earth is a sphere! 

Ron Webb wrote: Exactly.� It's not actually the moon that is rotated -- rather, the observer is rotated as he travels away from the equator along the curved surface of the earth.� In fact, we could measure the curvature of the earth by noting the amount by which the image of the setting moon is rotated, compared to what it looks like at the equator.� The degree of rotation would equal the degree of latitude above or below the equator.Cool!� You've discovered another way of proving that the earth is a sphere!�[IMG]smileys/smiley20.gif" align="absmiddle" alt="Thumbs%20Up" />

I was expecting this answer from you believe it or not. The Earth does not have to be a sphere for this phenomena to happen, as on a flat Earth you will still be looking at the Moon from the sides as you are moving away from it.

"From the sides" is not the same thing as "sideways".  If I look at a picture on the wall from the side, it appears distorted (as I said, a disc will appear as an ellipse), but the top will still be at the top.  To see it sideways, i.e. rotated 90�, you need to either rotate the picture on the wall, or rotate yourself (lie on your side).

Try it yourself.  Draw a picture of the moon and put it on the wall.  Then see if you can find a way to get the effect you're seeing just by looking at it from the side.  Now lie on the floor and look.

Abu Loren wrote: When the Moon is moving away then you will get a side ways view.

But the top will still be at the top.  Besides, you still haven't explained why, if the moon is a two-dimensional disk, looking at it from the side wouldn't make it look like an ellipse instead of a circle.

You can lie down if you want because it makes no difference as you are lying down on a flat surface (Earth).

But I'm not lying on my side -- and yet the moon appears to me as if I were.  Or as if my vertical is not the same as your vertical.

Look, here is what the moon looks like near the horizon in Saudi Arabia:


Notice the dark spot all by itself near the top?  That's Mare Crisium.

Now compare that to what it looks like in Canada.  (Sorry, I couldn't find an image small enough to paste directly into this discussion.  If you want, you can shift-click the link to open it in a separate window, so you can compare the two more easily.)

See how the image has rotated clockwise almost 45 degrees?  Mare Crisium is now much closer to the right side.  But it's the same moon.  It should look the same.  How can you explain this, unless the observer has rotated almost 45 degrees? And how is this possible on a flat earth?


Edited by Ron Webb - 27 October 2015 at 7:22pm