2007-12-06 19:10:40 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
As scythian says, we have twelve months because there are twelve periods from full moon to full moon in a year. If we base a calendar on the periods of the moon however (a 'lunar calendar'), we find that it becomes out of step with the seasons. This is because the period between two full moons is 29 1/2 days; so twwelve lunar months total only 354 days; wheras the rotation of the earth around the sun (a 'siderial year') takes 365 1/4 days.
Modern calendars have 'intercalary days' to make up for the extra days, and a leap year every four years to make up for the quarter day.
2007-12-06 23:32:11 · answer #1 · answered by AndrewG 7 · 0⤊ 0⤋
They are based upon the cycles of our Moon and coordinate somewaht with Sun cycles, but neither are precise, so there is much adjustment of calendars.
2007-12-07 00:18:49 · answer #2 · answered by miyuki & kyojin 7 · 0⤊ 0⤋
Why do we have MOONths?
Addendum excerpt:
O.E. monað, from P.Gmc. *mænoth- (O.N. manaðr, M.Du. manet, Du. maand, O.H.G. manod, Ger. Monat, Goth. menoþs "month"), related to *mænon- "moon" (see moon). Its cognates mean only "month" in the Romance languages, but in Gmc. generally continue to do double duty
2007-12-06 19:16:39 · answer #3 · answered by Scythian1950 7 · 1⤊ 0⤋
It was a way to organize time...it came from the moons appearance...
2007-12-06 19:17:21 · answer #4 · answered by AskMe 2 · 0⤊ 0⤋
so that you can say "I was born in May", not "I was born seven days after the third full moon in the warm time of the year"
2007-12-07 02:35:12 · answer #5 · answered by meanolmaw 7 · 0⤊ 0⤋
just to split a year in 12 somewhat equal parts....
2007-12-06 19:19:22 · answer #6 · answered by D'Costa... 1 · 0⤊ 0⤋