Talk:Year
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Should there be a mention that on other planets the year is different? --Daniel C. Boyer
It does seem to now: perhaps editted since your undated comment? As it looks out of date, lets agree if you do not repeat it within a month of this query I'll do a clean-up (talk)--BozMo 22:25, 9 May 2004 (UTC)
the same is here: http://www.sciencedaily.com/encyclopedia/year :P
Can some physics guru out there calculate the shorting of the year due to the mass loss of the sun over time. Because the rate is so gradual I do not expect there to be non equillibrium effects. Assuming a circular orbit, the radial orbit change(accelleration) should be able to be calculated from a force balance of the centripetal and gravitational forces. This radial change will give a new period since the kenetic and potential energy is related in orbital mechanics. I'm currious about the change in the period over time, since it has implications on the age of the earth, and the rate of energy output of the sun.
This also has an impact on the alinement of planets the ancients saw when the looked up at the sky. Does anyone know if celestia takes this into account when calculating historical star chart data?
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[edit] Seasonal Year edit
I removed "the hottest day of the year" as an example starting point for a seasonal year because it is not a definite/conclusive starting point in that there could always be a unexpected hotter day later on. All the other given examples have definite starting points, for instance when flowers start to bloom, you know that's the start of that flowers "season". I also added "the first scheduled game of a certain sport" to throw in a man-made seasonal year example into the mix. Comments?
[edit] Astronomical Year section reformatting
I added bullets to the listings of the astronomical years because I think it looks better in general and breaks up the different types for easier reading. I don't know if doing this is within Wiki-policy, anyone care to comment or take a vote on it?
[edit] Calendar repetition
I think it would be nice to have information regarding calendar repetition, that is, is there a way to tell when is this year's calendar going to be repeated? For example, 2005 is a Common year starting on Saturday. When in the future will the 2005 calendar be repeated, like August 12 will be friday and all other days will be the same week day as in 2005? When in the past was it repeated like that?
I've never heard of any such calculations, just wondering if anybody has.
- You cite a wikipage that already lists the years that have identical calendars, so I gather you don't just want to know what years are identical, but how to determine them by calculation. Unfortunately, I don't know of any such calculation. I can only mention that whatever the retitions are, they must repeat on a 400-year cycle. — Joe Kress 18:54, August 12, 2005 (UTC)
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- All solar calendars with a leap year every four year and a 7-day-week repeat in principle every 28 years (=4x7). But a additional leap year interrupts this so-called solar cycle. Thus Gregorian calendar years 1801, 1829, 1857, 1885 began with a Thursday, like 1901, 1929, 1957, 1985 with a Tuesday. There are exactly 20871 weeks in a Gregorian 400 years cycle, so it well repeats after each full cycle. All in all, there exist only 14 calendars. 7 for common years, 7 for leap years.
--Peter 2005 12:51, 14 August 2005 (UTC)
- All solar calendars with a leap year every four year and a 7-day-week repeat in principle every 28 years (=4x7). But a additional leap year interrupts this so-called solar cycle. Thus Gregorian calendar years 1801, 1829, 1857, 1885 began with a Thursday, like 1901, 1929, 1957, 1985 with a Tuesday. There are exactly 20871 weeks in a Gregorian 400 years cycle, so it well repeats after each full cycle. All in all, there exist only 14 calendars. 7 for common years, 7 for leap years.
[edit] Oriental great year
The following statement was added to the article by 71.36.34.14. I have moved it here because I have never heard of it even with my fairly extensive knowledge of Chinese astronomy and Creation myths, and no citation is given. It is doubtful that it is the source of the Western 24-hour day because the Chinese used a clock with twelve double hours, not one with 24 hours. The standard explanation for the Western 24-hour clock is that the Egyptians used 24 seasonal hours (12 daylignt and 12 nighttime).
- Oriental astronomy puts the length of one Great Year at 24,000 years comprised of one ascending cycle of 12,000 years and one descending cycle of 12,000 years. Some scholars believe this may be the original basis for the current system of daily time; a 24 hour day with 12 hours of increasing light (AM) and 12 hours of increasing darkness (PM).
A citation is needed before it can be added to the article. Don't use the weasal words "some scholars". Cite which scholar or scholars.
— Joe Kress 01:00, 22 November 2006 (UTC)
