The local moon

In the first century of our era, Plutarch poked fun at people who thought that the Athenian moon was better than the Corinthian one. Reading that, I though about the scene in Roots, where two Africans are sitting outside an evening at the plantation, and one of the ask if it’s same moon as where they were born, and the other guy answers something along the lines of “Probably not, everything else is different around here so why would the moon be the same”?

But who’s right? Does the moon look different at some place on the earth? Does it look bigger near the equator, or on tall mountains? Is it a different color somewhere, or diffent apparent shape? Is there anywhere on earth (I was thinking the poles maybe) where the moon can never be seen? Furthermore, has the moon changed in appearance during the earth’s long history, so that (say) the Romans had a different moon than us? Has it always been the same part of the moon that has been facing the earth?

It’s upside down in the southern hemisphere.

No, it’s upside-down in the northern hemisphere, GuanoLad. :wink:

Unless a whopping great piece of space rock plowed into the moon between the time of the Romans and now … no. It hasn’t changed. It’s got some flags and stuff on it now, though.

Not to any noticable extent. By moving around on the Earth, you can get the size of the Moon to vary by about 2% - not enough to make a difference to the unaided eye.
However, there is the Moon Illusion. Due to some trick of our visual system, people think the Moon is bigger when it’s lower down in the sky. There have been numerous threads on the subject and possibly a column by Cecil at some point - worth digging out.

The apparent colour of the Moon can change due to local atmospheric effects. Classic examples are because of smoke and dust from the likes of forest fires and volcanic eruptions.
Its colour will also change during a lunar eclipse, but that change can be seen from everywhere on Earth that can see the Moon at the time of the eclipse.

Nope. The Earth’s tilted quite a bit and so the Moon doesn’t go round the equator. There are a couple of other effects involved, so from any particular point on Earth how high up the Moon is varies a lot over the seasons and the years.

Not that is known, at least in the last few thousand years. There’s almost certainly been no impact on the Moon in historic times sufficient to change its appearance to the naked eye.
(There is the Gervaise of Canterbury report - a medieval chronicler may have recorded a biggish impact on the Moon. However, this is controversial and the suggested change was both relatively small and on the far side. It wouldn’t have permanently changed how it looked from Earth.)

In historic times, yes. There are slight wobbles that mean that the face towards us shifts about a bit, but again not enough to be noticable.

One way in which how the Moon appears depends on your location is that what you see is probably slightly culturally determined. The Moon’s actually a fairly small object in the sky and it’s harder than you probably expect to draw what it looks like using just your naked eye. Expectations about seeing the Man-in-the-Moon or whatever are quite powerful in those circumstances.

Can an AussieDoper (or KiwiDoper) please post a link to a photograph of “your” moon. I’d love to see how it compares to ours.

Thank you.

I don’t think that’s necessary. You just need to think about it. If you are north of the Tropic of Cancer, the Moon is always to your south in the sky. If you are south of the Tropic of Capricorn, the Moon is always to your north in the sky. (And if you are between the two tropics, it is sometimes to your north, and sometimes to your south).

If you see the Moon to your south, the the North Pole of the Moon will be towards the top. If you see the Moon to your north, then the South Pole of the Moon will appear to be towards the top. Very simple, really.

Yeah, just take a photo of your own moon and turn it upside down!

There’s also a difference in the orientation of the Moon from different latitudes. For example, if you observe a waxing crescent moon setting at the equator, it will look like a boat, or a U-shape. For someone at high latitudes watching the same moon set at the same time, it will look more like a C <–but this C is backwards, incidentally. I guess actually it would look like this --> )

This would only follow if the moon orbits the Earth in the same plane as the sun - is this really the case? And if it is, does that mean that the moon “flips” upside down seasonally in the tropics?

Well, the Sun doesn’t go around the Earth…Anyway, the plane of the Earth’s orbit around the Sun is called the ecliptic, and the Moon’s orbit around Earth is tilted by about 5 degrees from that.

The Moon’s orbit around the Earth is very close to being in the same plane as the Earth’s orbit around the Sun.

In the tropics, both the Sun and the Moon rise in the east, go roughly over head, then set in the west. Part of the year, the path is a bit to the north of overhead, and part of the year, it’s a bit to the south of overhead. (On the Equator, those two parts of the year are pretty well equal – they aren’t exactly equal, because the orbits are elliptical, not circular).

Suppose the Moon is directly overhead. if you stand facing south, then bend your head backwards to lkook at the Moon, the north of the Moon will appear to be at the top. Then, if you turn around 180 degrees to face north and bend your head backwards again to look at the Moon, the south of the Moon will appear to be at the top.

Not meant as a hijack exactly, but The Local Moon would be a kick ass name for a band.

Feel free to use it.

But that would mean that the moon would “flip” rather quickly in the tropics, probably from one night to the next, as soon as the position of the moon changes from north of where you stand to south. This might not be very noticable on a full moon, but a with a crescent moon…

If you are in the Northern Hemisphere and you look at the moon, then lean over as far as possible backwards, you can sometimes see uranus.

:slight_smile: sorry.