Talk:2172: Lunar Cycles
Is it possible that the size of the Earth and the moon are supposed to be comparisons of how big the Earth looks from the moon vs. how big the moon looks from the Earth? 22.214.171.124 (talk) (please sign your comments with ~~~~)
- Why would that have a cycle different from the distance cycle?Barmar (talk) 20:20, 5 July 2019 (UTC)
Where is the total eclipse of the heart? Actually, why do we not have a total eclipse of the hart - when all deer are hidden?
A very quick and dirty (probably flawed, until I can plug things into a suitable visualiser to check and/or improve my initial idea) attempt to describe the nature of the square/circle oscilations of the Moon might well be smething like |r.cos(θ)−r.sin(θ)|.|sin(t/λ)| + |r.cos(θ)+r.sin(θ)|.|sin(t/λ)| + |r.√(2/π)|.|cos(t/λ)|=k ...only then you'd also want to make k a quantity also multiplied by the relative Earth/Moon size cycle. Either way, YMoonMV. 126.96.36.199 00:41, 6 July 2019 (UTC)
- Isn't the square/circle a reference to rounded corner rectangles. If you increase the corner radius of a square, enough, you get a circle. SDSpivey (talk) 05:37, 6 July 2019 (UTC)
Does anyone know of a real chart similar to the format of the last panel? That might be a cool thing to link to. 188.8.131.52 16:38, 6 July 2019 (UTC)
I refer the honourable gentleman to the answer I gave earlier 184.108.40.206 20:10, 8 July 2019 (UTC)
I remember there being a blue blood supermoon or some crazy thing like that once a year or so back. Mostly because I dreamed that it was also a falling moon and woke up very worried. --220.127.116.11 00:18, 12 July 2019 (UTC)
I think this is primarily an astrology joke. Astrologers often use astronomical cycles (both real and made up) to "predict" future events or explain historic events. By having enough cycles, they can usually come up with results like "skinny jeans are always popular whenever the happy moon is in Pices and wet Mars is in the same Chinese zodiac as Mercury".
You know, I kind of expected a joke about periods 18.104.22.168 01:49, 10 July 2019 (UTC)
I think this is unlikely - the jokes all hinge on cycles of the moon, and don't reference any dates or other celestial bodies in the way astrology does. 22.214.171.124 12:33, 8 July 2019 (UTC)
Phase x distance and supermoons
I've been absolutely nerd-sniped by the "Phase x distance" in the bottom diagram. As far as I can figure out, if you multiply phase and distance, you should end up with a new cycle with a period of (29.5 x 27.5) = 811.25 days, which is about 2 years. A supermoon is when a full moon occurs when the Moon is closest to the Earth, so this phase x distance figure is effectively a supermoon detector - that's why supermoons occur at the peaks in Randall's diagram.
But when I looked into supermoons a bit - specifically this diagram from Wikipedia - other sources shows supermoons occurring on a yearly cycle - we supposedly get them every year. How can that be the case, if the two lunar cycles only synchronize every 2 years? It seems to me like there has to be at least one out of every two years where we get no supermoons at all - ie. the full moon is always coinciding with the moon being furthest away.
- I figured it out; it turns out that I was simply wrong about how to calculate the length of a combined cycle. This graph shows that the two cycles would coincide every 400 days or so. Still can't figure out what "phase x distance" is meant to represent, though. Hawthorn (talk) 17:54, 6 July 2019 (UTC)
Earth/Moon changing size
While I do know that the Earth and Moon can technically change size due to accretion of interstellar material, the amount is so negligible that I don't even think it's worth mentioning. I suspect the Earth changes size more from thermal expansion and contraction than from accretion. Hawthorn (talk) 13:03, 9 July 2019 (UTC)
The harvest moon does have some astronomical significance: the time of moon-rise from day to day changes less around the harvest moon than at any other time of the year. Wikipedia and its source say that this allowed harvest work to continue into the night during the days after the full moon without a significant period of darkness between sunset and moon-rise. 126.96.36.199 05:59, 10 July 2019 (UTC)