Talk:Moon: Difference between revisions

Mass not using normalized notation

Please change the listed mass (on the right under "Physical characteristics") from "0.07342×10²⁴ kg" to "7.342×10²² kg".

The current form is technically correct use of scientific notation, but not normalized as these figures usually are, such as on the Wikipedia pages of other astronomical bodies (compare with Triton's mass).

It's like answering the question "How old is your daughter?" with "She's 0.012 millennia old." Mathematically correct, but poorly formatted; "She's 12 years old" is a more readable answer. 67.82.160.238 (talk) 14:15, 4 December 2015 (UTC)

The reason, I think, is that the NASA table gives the mass in that format, but it's a comparison table, and ours isn't, so Standard Form wins in my opinion. I've restored Standard Form. Dbfirs 14:32, 4 December 2015 (UTC)

References

Orbital period

I think it is interesting to note somewhere that calculating the Moon's orbital period using just the mass of Earth results in the erroneous 27.45 d (a discrepancy of about 4 h!). Including the mass of the Moon itself, which is technically required, results in 27.28 d, much closer to the actual value of 27.32 d.

However, the 'small' remaining discrepancy cannot be explained by a discrepancy in the used masses or distance, nor uncertainty in G. It would require a rather significant change in the mass, distance, or G used. Any ideas how to explain this last part? --JorisvS (talk) 19:51, 6 December 2015 (UTC)

Try including the tidal effect produced by the gravity of the Sun. DOwenWilliams (talk) 20:35, 6 December 2015 (UTC)

How can you do that? --JorisvS (talk) 10:01, 7 December 2015 (UTC)

Semi-protected edit request on 18 December 2015

Planning to add new info to the existing info regarding the moon orbital characteristics. Description of edit request : Addition to moon orbital characteristics.

ratio of distance between moon and earth to moon diameter ~= approximately 108. similar to ratio of distance between sun and earth to sun diameter ~= approximately 108.

Reference from https://en.wikipedia.org/wiki/Moon moon orbital characteristics and moon Physical characteristics both will provide mean distance between earth & moon and moon average diameter. Write2indhu (talk) 18:53, 18 December 2015 (UTC)

Not done: I presume by Orbital Characteristic, you mean the infobox at the start of the article and to the right. This infobox is built by a template, and that template does not have a field for the characteristic you are proposing to add. -- ferret (talk) 20:59, 18 December 2015 (UTC)

We already record this fact in words: "The apparent size of the Moon is roughly the same as that of the Sun, with both being viewed at close to one-half a degree wide. The Sun is much larger than the Moon but it is the precise vastly greater distance that coincidentally gives it the same apparent size as the much closer and much smaller Moon from the perspective of Earth." I suppose we could add the numerical ratio of distances to that section. What does anyone else think? Dbfirs 21:13, 18 December 2015 (UTC)

As a passerby to the article, that sounds good to me. -- ferret (talk) 22:46, 18 December 2015 (UTC)

Menstrual cycle

Women's menstrual cycle is 28 days, the same as the lunar cycle. Many other Wikipedia articles state widely known and seemingly obvious facts, so why not this one? Smithfarm (talk) 10:37, 24 December 2015 (UTC)

Because this is a featured article and featured articles' facts are cited to reliable sources. And the lunar cycle is 29.5 days, not 28. And plenty of other mammals have shorter or longer menstrual cycles. Serendi^podous 13:47, 24 December 2015 (UTC)

Is the orbital period correct?

The article states the Moon's sidereal period is 27.321582 days but googling this number along with the synodic period shows other sources quoting the sidereal period as roughly 27.321661 days and taking 27.321582 days as the tropical period. At least a reference should be added to back it up. JensPetersen (talk) 10:09, 9 January 2016 (UTC)

Yes, I think you've spotted an error here. Many websites do quote 27.321582 days, but our article Lunar month makes the distinction between the two. Which figure is more appropriate, or should we quote both? Dbfirs 11:38, 9 January 2016 (UTC)

(Sorry there is actually a reference: through a journal paywall.) I think Sidereal is most common for "Orbit Period", but maybe best to confirm with the template owner? Alternatively possibly 27.322 days is good enough (it would cover both). The Lunar Month article is nice: seems the Synodic period is a mean. JensPetersen (talk) 15:54, 10 January 2016 (UTC)

It might be nice to add a link to [Lunar month] too. JensPetersen (talk) 15:58, 10 January 2016 (UTC)

Actually the Orbital Period link is clear that in Astronomy the default meaning is the siderial period (ie wrt the stars), so it should be changed to 27.321661 d. JensPetersen (talk) 15:46, 13 January 2016 (UTC)