Talk:Moon

Reflectance

The lead says "It is the brightest object in the sky after the Sun, although its surface is actually very dark, with a similar reflectance to coal." As the Moon's reflectance varies very noticeably over its surface, it would be good to clarify which parts are supposed to be similar in reflectance to coal. Is it the dark parts? 86.181.205.25 (talk) 14:20, 9 February 2011 (UTC)

Diagram of phases

I cannot make head nor tail of the "New Moon" insets in the diagram of the Moon's phases in the "Appearance from Earth" section. What are they showing? What is the ring of red dots, and what are the various mutky murky dots and circles? 86.181.205.25 (talk) 14:42, 9 February 2011 (UTC)

The ring of red dots represents the spot in the (day) sky where you can't see the New Moon, and I guess the dots and circles represent lens flare because you're looking near the Sun. —Tamfang (talk) 00:44, 10 February 2011 (UTC)

Oh! Thanks. I think this needs explaining in the caption, or, better still, the insets need replacing by something more recognisable. To me it looks like a system of about four planets/moons with a dotted path showing an orbit or something. 86.176.209.219 (talk) 13:03, 12 February 2011 (UTC)

Goof

{{editprotect}} The first note in the note section isn;t correctly formatted and leaves a large area of nothing between the "The" and the next thought. I can see words in the note here on the article template when I click edit, but I cannot fix the problem cuz the article is locked. 75.19.69.26 (talk) 11:21, 10 February 2011 (UTC)

I see no problem. Please be more specific on which words/code/note (there are notes and footnotes) is wrong. Materialscientist (talk) 11:49, 10 February 2011 (UTC)

Direction of the Moon's Axis of Rotation

I have seen nothing in this or associated articles which appears to give the direction of the Moon's Axis of Rotation with respect to the Celestial Sphere (which I suppose to be at least close to constant) - the Right Ascension and Declination, which are given in the top right box in the articles on the planets.

There is a figure for tilt, but it's not clear to me in which direction the tilt is, or how to use it.

It would also be nice to see expressions for the RA & Dec of the perpendicular to the Moon's orbit - the angular momentum vector of the Earth-Moon system - as a function of time (period 18.6 years). Or the mean RA and Dec, and the radius in degrees of its presumably circular motion, and the phase of that motion from a given position as a function of time.

94.30.84.71 (talk) 22:09, 21 February 2011 (UTC)

It precesses rapidly. See Orbit of the Moon#Inclination. —Tamfang (talk) 09:39, 22 February 2011 (UTC)

Albedo

The albedo figure seems a little bit too high, and the reference's abstract talks about a broadband albedo, which presumably includes near infrared. From the article Bond albedo the geometric albedo is 0.123, and from geometrical considerations and the apparent magnitudes of Sun $m_{Sun}$ and Moon $m_{Moon}$ it should be ${\frac {100^{(m_{Moon}-m_{Sun})/5}}{r_{Moon}^{2}/d_{Moon}^{2}}}=0.125$, where $r_{Moon}$ is the radius of the Moon and $d_{Moon}$ is the distance of the Moon from the Earth. Icek (talk) 05:46, 22 February 2011 (UTC)

Etymology

The current etymology section is rather disappointing. If we're going to discuss the entymology of 'moon', we should at least go back a little further where things get interesting and we find out that 'moon' is related to the words 'month' and 'menses'. Anyone have an account at oed.com? Kaldari (talk) 18:14, 7 March 2011 (UTC)

Go down to "In culture". Serendi^podous 18:41, 7 March 2011 (UTC)

Earth's other natural satellites

This post is not to criticize any information relating to the Earth's Moon, except one point that is not addressed. Earth has other orbiting satellites, none particularly large, but that doesn't mean they are not of interest. I came to seek information regarding them and was disappointed, and it is unlike Wikipedia to disappoint on any topic regardless of how obscure or questionable. Surely there is someonewho has access to this information ? I currently do not, or I would not have come seeking it. —Preceding unsigned comment added by 203.45.60.45 (talk) 01:08, 10 March 2011 (UTC)

See Note 4 and Quasi-satellite. Iridia (talk) 05:49, 10 March 2011 (UTC)

NEO Objects

As a point of clarification it may be valuable to mention Earth's NEOs, and why they aren't considered to be satellites of Earth. I believe the public has been misinformed about objects like Cruithne being satellites of Earth.

This is not relevant: Even if the Apollonid NEOs were satellites of the Earth i.e. the earth permanently occupied one focus of their elliptical orbits, they have no place here because they are not The Moon. (Valhalan (talk) 04:59, 11 March 2011 (UTC))

In Culture

I'm a little surprised to see that this section has not been expanded more fully. For example the effect of the moon upon human reproduction has long been studied; indeed as reported the same Indo-European root for "moon" has led, through Latin, to the word "menstrual". Studies of very many females has led to the conclusion that the average human menstrual cycle is exactly one lunar month and the gestation, from conception to birth, is exactly 9 lunar months. Further, the onset of menstruation tends to cluster around the New Moon, with almost 30 per cent of menstruations commencing at this time. See: Acta Obstetricia et Gynecologica Scandinavica: The Regulation of Menstrual Cycle and its Relationship to the Moon, 1986, Vol. 65, No. 1 , Pages 45-48 or at http://informahealthcare.com/doi/abs/10.3109/00016348609158228 Yet further, the effect of the Moon on human romance, poetry and art is vast and yet has barely been touched upon in the Article. In history, the outcome of battles and military campaigns which have changed history's course has been determined by the light afforded by the moon; for example at the Alamo during the process of freeing Texas from Mexico in 1836, the Mexican casualties were far higher due to the near-full moon than they would have been at New Moon, and this is turn decided the subsequent outcome at San Jacinto when Texas was finally won by the Rebels, who found themselves with far fewer Mexicans to fight. If we are to speak of spacecraft visiting the Moon in this article, let us not forget that if history had been different, then no spacecraft might yet have been there. The Alamo precipitated a war in which America won not only Texas (eventually) but also most of the South-west; had this gone the other way modern America might not have been economically powerful enough for Apollo. Calendars, tidal power generation, ... even the feeding patterns of sharks and the catch yields of fishermen and anglers varies according to lunar cycles. Much room for expansion!! (Valhalan (talk) 04:38, 11 March 2011 (UTC))

The word "menstrual" is derived from the Greek word for "month"; it has nothing specifically to do with menstruation. As to the rest, that's all good, but it needs sources. I agree that that section needs to be expanded, perhaps even into its own article, but it's not something that can be corrected in one go. Serendi^podous 08:03, 11 March 2011 (UTC)

Volume of the Moon

{{editsemiprotect}} There seems to be a typo in the value of the Moon's volume. It is given as 2.1958 km³, but if one computes it from the equatorial and polar radii (1,738.14 km and 1,735.97 km respectively), one gets 2.19685 km³ (which rounds up to 2.1969 km³). Could someone fix this? 129.206.34.51 (talk) 15:21, 11 March 2011 (UTC)

If the Moon is not a perfect oblate spheroid, the discrepancy may not be an error. —Tamfang (talk) 19:32, 11 March 2011 (UTC)

I'd leave it as it is: the given figure could be very accurate. It is less than your figure by about 11 million cubic kilometers. However if we start with your figure, and then subtract the below-ground volume of all the craters, we get an estimated figure very close to the Article's figure. For example, the below-ground volume of Copernicus is 25,500 cubic kilometers, Clavius another 139,000, Tycho 26,600, Archimedes 11,400, Plato 9,300... So how much for the lot? 11 million sound about right? You've worked out the volume of a smooth oblate spheroid -- and forgot about all the craters. (204.112.68.51 (talk) 00:14, 12 March 2011 (UTC))

204.112.68.51 had some good ideas. However, do we have any "official" sources which say either answer? In about a week from now, the moon will be the closest to earth that it's come for 18 years or so -- perhaps someone will do some sort of experiment and give us a more precise figure for the moon's mass (and thus its likely volume based on what we know of its composition). In the meantime, in the absence of another source, I'm inclined to just leave the volume listed. If there is a more scientific source that says one way or the other, please put the edit requested template back up. If you'd like any further help, contact me on my user talk page. You might instead want to put a {{help me}} template up on your own user talk, or put the {{edit semi-protected}} template back up on this page and either way someone will be along to help you. :) Banaticus (talk) 06:21, 12 March 2011 (UTC)

Better far side picture.

If there was an easy button to click saying "Click here to contribute an image to this article," I would. http://www.space.com/11186-photo-side-moon-nasa-lunar-orbiter.html has a newly released hi-quality image that's not as striated as the current one. Pär Larsson (talk) 16:39, 22 March 2011 (UTC)

Atomic Blast theory

I put back this section, adding more qualifications as to "speculative" and "support in literature". The simple fact that it is discussed in the popular literature means that it should be mentioned. If people think it is bogus, then reasons should be added -- are there any papers that reject it? (I do recall when the idea that a meteor killed the dinosaurs was considered very unlikely.) Tuntable (talk) 00:29, 29 March 2011 (UTC)

"An alternative speculative proposal for the formation of the moon is that it was blasted into space by a massive nuclear reaction near the core of the early earth (when fisile material was more prevalent). However, this proposal is not widely supported in the literature."

Ok. Let me go through your statement.

• No papers on this hypothesis (it is not yet a theory) have been published in a peer-reviewed scientific journal. They have been put on the preprint server arXiv. This is not a peer reviewed forum: an author should have an affiliation with a scientific institution in some manner, but that is all that is checked. It's a good place to put a speculative idea.
• Mention in the popular literature is not the same as mention in the scientific literature. There are many things on Wikipedia that are in the popular literature, to the encyclopedia's benefit. The scientific discussion in this article is not the appropriate place for adding ideas that do not have significant amounts of evidence behind them. The collision theory has a great deal of evidence behind it at this stage: the burden on a new hypothesis is to explain all that evidence and work in situations where the collision theory does not. The pop-sci magazine article you have provided does not suggest this is the case.
• A quick whip around ADS does not show any discussion of such a theory. This might have something to do with it not being published... Iridia (talk) 04:44, 29 March 2011 (UTC)

I think you miss the point. The simple fact that it appears in popular literature means that the theory is notable. Certainly not necessarily sound, but notable. Therefor I note it. People will be curious to know if the theory is widely supported, as I was. So I have put it back with your additions about not published, which is important, and I did not realize that it was completely unpublished.

If it was well known by the scientific community that that the theory was nonsence, then it would be even more important to state that. Precicely because it is published elsewhere.

As to notability, below are some references that come up on the first page of Google.

http://www.physorg.com/news183884450.html

http://articles.timesofindia.indiatimes.com/2010-01-30/science/28146521_1_earth-and-moon-lunar-samples-fission-theory

http://www.dailymail.co.uk/sciencetech/article-1246872/Was-moon-created-nuclear-explosion-Earth.html

http://news.discovery.com/earth/did-a-nuclear-blast-give-birth-to-the-moon.html

How notable? I reckon about two sentences is enough.

Tuntable (talk) 23:52, 3 April 2011 (UTC)

Any theory on the Moon formation (which does not sound ridiculous to a layman) would be picked up by some popular websites/publishers - this did happen in the past for other theories, and the media can not be held responsible for propagating unreliable information. However, for inclusion to a core article like this, a theory should either be accepted by science community, or have really impressive notability, which is not seen in this case. Materialscientist (talk) 00:04, 4 April 2011 (UTC)

I would refer you to Notability guidelines do not limit content within an article. Wikipedia should be a source of knowledge to the unwashed masses as well as to experts in field. The list of references above clearly makes it sufficiently notable for a couple of sentenses. Probably not a new section, but certainly just a couple of sentenses. And yes, that might mean in general that some small proportion of artilces are to address unsupported theories just because they are talked about elsewhere. That is OK, indeed, it is one of the reasons to have wikipedia.

I actually came to the Moon article to find out whether the blast theory was credible, and found the hole. Stating that it has not had coverage in the scientific literature addresses my question. So Iridia comments were useful to me. But they should be in the article, not the Talk.

It is not the goal of wikipedia to only be pure. It should address practical needs for information. Sure, we don't want too much noise, but that is hardly the case here.

I also tidied up the huge initial sentense about formation, and put it after the main theory where it probably belongs. There was a trailing sentense about explaining the angular momentum, which was unclear. I have made it "Some of these hypotheses"... But if someone could clarify which ones that would be helpful. (It was not at all clear in the original.)Tuntable (talk) 00:45, 5 April 2011 (UTC)

Look, Tuntable, you seem to be confused about the definition of a reliable source. If you're going to start quoting policy, then please go and read the reliable source policy, in depth. Those are not reliable sources that could provide notability for this situation. This is not an article where brand-new scientific theories can be thrown in, without them having had discussion in the peer reviewed literature, which this hypothesis (not a theory!) does not have.

Please do not continue adding the material until there is consensus. As it is, both Materialscientist and myself disagree with you.

If you found the formation section unclear, I'll have a look and see if I can reword. (Bear in mind that is the text that was approved by many editors at the article's review). Iridia (talk) 03:04, 5 April 2011 (UTC)

Add me in too as objecting to inclusiom, that is abosultely a fringe theory, the source itself says "outlandish new hypothesis". And the hypothesis posits a D-double-prime layer as existing at the time of the Moon's formation, where's the backing for that? And from what I've read about D-double-prime, it's a phase transition, not a change in mineral concentration. What I would propose is a sister site: trivia-en.wikipedia.org, where this sort of material could be collected. It has indeed appeared in popular media and I'd be fine with seeing it reflected somewhere within the grand wiki-scheme. But certainly not within a serious and important article. Sorry Turntable, not sufficiently significant for inclusion here. Franamax (talk) 09:45, 5 April 2011 (UTC)

Oops, I'm wrong on one aspect, a crystal phase transition could certainly cause preferential conecntration of one or more elements, and yes that could cause a criticality problem in unique circumstances. That's likely the whole basis of the proponents argument, but of course it's quite hard to evaluate without seeing some actual peer-reviewed numbers. The rest of my comment stands as written. Franamax (talk) 09:51, 5 April 2011 (UTC)

Light seconds

The one thing I dont see in the article is the time it takes for light to reflect from the moon to the Earth. Granted there are difficulties in giving a precise number due to changes in orbital distance, sphericity of both bodies, etc. And its not difficult to figure it out based on the average orbit distance of 350 600 km - somewhere around 1.169475721 light seconds. Still it should be mentioned somewhere in the article. -161