|WikiProject Days of the year|
Selected anniversaries for the "On this day" section of the Main Page
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- 1 Feb 29th NOT the definition of a leap year!
- 2 Feb 29th NOT the definition of a leap day, either!
- 3 Question re Feb 29.
- 4 Waiting an extra day?
- 5 Questionable Facts
- 6 Leap day is more likely to fall on a Monday than on a Sunday
- 7 Women proposing?
- 8 Kayla Rolland
- 9 Unusual date?
- 10 Birth of Richard Ramirez
- 11 Ash Wednesday
- 12 feb 29 not 60th AND 61st day
- 13 Bissextile
- 14 Birthdays suggestion
- 15 When this day falls in opening
- 16 Happy Leap Day
- 17 notability.
- 18 Typo in Birthday listing
- 19 Why is it called "LEAP"?
- 20 Excel Day Count
- 21 Divisible by 900
- 22 Three paydays in February?
- 23 Semiprotection review
- 24 Incorrect information
- 25 What the 24 hour February 29th rotation does
- 26 Cycles
- 27 29th? No.
- 28 Misinterpretation of New Zealand Law
- 29 Century years
- 30 February 24
someone wrote: :Not true. February 29 is not added in leap years. February 24 is.
Was that someone thinking of the Roman or Julian calendar? February 24 occurs every year in the Gregorian calendar, so far as I know. --MichaelTinkler — Preceding undated comment added 16:30, 8 November 2001
No, in both the Roman, the Julian and the Gregorian calendar, February 24 is the added day. Of course February 24 exists in non-leap years also, but it is a different day. The day called "Feb. 24" in non-leap years is actually "Feb. 25" in leap years, and the non-leap year "Feb 28" is leap year "Feb 29". The origins go back to the Roman period -- Feb 24 is the bissextile day -- I think talk:leap year explains it. -- SJK — Preceding undated comment added 16:33, 8 November 2001
- While it's historically true that February 24 was the "added" leap day up until 1996, the European Union, drawing upon its ineffable wisdom, has declared that February 29 would be the leap day starting in the year 2000. Best to finesse it with 'occurs'. -- Someone else 23:51 Nov 1, 2002 (UTC)
- The added day being February 24th makes no sense at all. What possible rational basis can this claim have? The 24th of February is the 24th of February. How can the 25th of February in a leap year be "really" the 24th? The days of a month are counted from the beginning to the end - 1st, 2nd, 3rd ... 23rd, 24th, 25th, ... and so on. What, then, is the "real" date of what we call February 24? The 24½th? This sort of weirdness needs a lot more explanation than just the bare stating of a supposed fact. I suspect some sort of stupid hoax here. Koro Neil (talk) 03:43, 12 December 2013 (UTC)
- So my understanding, which may be flawed, is the following: the Romans counted dates backward from the next reference date, instead of forward from the first of the month. So for instance, instead of saying 'the 27th of February' as we do, they would say 'three days before the first of March'. And what they did during leap years is count as follows: 'eight days before the first of March, seven days before the first of March, six days before the first of March, six days before the first of March again, five days before the first of March…'. So, to translate it into modern terminology, they labeled two consecutive days as both the 24th of February. AJD (talk) 04:25, 12 December 2013 (UTC)
Under births, one of the years in 1763. But 1763 is not a leap year. What is the correct year? Eric119 23:02 Apr 22, 2003 (UTC)
- It looks like Ann Lee's dates are Feb 29, 1736 - Sept 8, 1784, so someone just flipped two digits. Fixed now. -- Someone else 23:25 Apr 22, 2003 (UTC)
The opening paragraph is wrong -- it says "with one exception", but actually there are two exceptions to the simple rule (one slightly arcane xception that century years are excluded, and one even more arcane exception that quatracentenary years are included). I tried to fix this earlier, but someone reverted my changes; I had done quite a rewrite as an attempt. So rather than try again, I'll just mention the mistake here, and hope someone else will fix it this time, and maybe it will last :) Pagan 09:53, 1 Jan 2004 (UTC)
>>>If you can divide the century by 400 and get a whole number, it's a leap year (leap century). So 2000 was a leap year. 2100, 2200 and 2300 are not. Pity the poor slob born on Feb-29, 2096. He won't have a birthday for 8 years! BTW. The leap-century math was kinda ignored by MicroSoft when they wrote Excel. Look on "The Leap Year Day Honor Roll" webpage and you'll get all the gory details. —Preceding unsigned comment added by 184.108.40.206 (talk) 20:32, 8 January 2007
There is a tradition that women may make a proposal of marriage to men only on February 29
Have you heard the joke that February 29 is Job's birthday? When he said 'Let the day perish wherein I was born', God didn't grant his request entirely but made a concession to him by obliterating the day three years in four. Jess Cully 10:48, 29 July 2005 (UTC)
Feb 29th NOT the definition of a leap year!
See Soviet revolutionary calendar or February 30. In odd circumstances there has been a Feb 29th outside of a leap year. Shouldn't this sentence bee removed? —Preceding unsigned comment added by 220.127.116.11 (talk) 03:43, 10 July 2004
Feb 29th NOT the definition of a leap day, either!
Question re Feb 29.
Is it better that Feb 29 falls:
- in the middle of the year, or
- at the end of the year?
When March was the first Month, and December the 10th month, Feb 29 did indeed fall at the end of the year.
Syd1435 05:58, 2004 Nov 22 (UTC)
Agree that the end of the year is the best place for leap day. Let's have December 32 in leap years and extend the Christmas-New Year festivities. Jess Cully 10:44, 29 July 2005 (UTC)
People (Northern Hemisphere)have argued -- sometimes seriously -- along these lines: You know how bad the weather is in February? Why have an extra day then? Why not add July 32 and have an extra day of good weather? WHPratt (talk) 16:43, 11 February 2009 (UTC)WHPratt
The point of Leap Day being inserted at the end of February begs the question "why February?" Of course the reason is as explained above (in the Roman Calendar it was the last month of the year. This may seem a minor point, but I think it should be mentioned on the main page, which is locked. SGW1009 17:49, 14 January, 2009 (UTC)
- Under English law, up until 1750, the 25th of March was the start of the year. The Calendar (New Style) Act 1750 (24 Geo 2 c.23) decreed that 1751 would end on 31 December and 1752 would begin on 1st January; that the 2nd September 1752 would be followed by 14th September 1752; that an ordinary year had 365 days and a leap year had 366 days; that every four hundredth year starting at 2000 would be a leap year; that otherwise every hundredth year starting at 1800 would not be a leap year; otherwise every fourth year was a leap year as had been the case under the old (Julian) calendar. The act is explicit about whether 1800, 1900, 2000, 2100, 2200, 2300, 2400 and 2800 are or are not leap years. This act also set the rules for calculating Easter until at least 8500! It might help if this arcane method of implementing the new calendar was explained. Also, because this Act was passed before American Independence, I assume it would also apply in the USA, as well as any British Commonwealth country, together with any associated Common Law about how 29th February is treated. - Cameron Dewe (talk) 10:13, 11 June 2013 (UTC)
Waiting an extra day?
Article says: An English law of 1256 decrees that in leap years the leap day and the day before are to be reckoned as one day for the purpose of calculating when a full year has passed; thus, in England and Wales a person born on February 29 legally reaches the age of 18 or 21 on February 28 of the relevant year. In the European Union, February 29 only officially became the leap day in 2000.
If the law really does say that, that would also mean that someone born on February 28 on a non-leap year isn't 18 until February 29 if that is a leap year. —Preceding unsigned comment added by Random832 (talk • contribs) 14:43, 2005 August 10 (UTC)
- No, if you are born in the middle of April 2nd, you become 18 at the beginning of April 2nd. 12 AM February 28 is the beginning of the "day" that includes February 28 and February 29. DenisMoskowitz 15:45, 2005 August 10 (UTC)
In "The Pirates of Penzance" - an Operetta by Gilbert and Sullivan: Frederic encounters Ruth and the Pirate King. They inform him that his apprenticeship was worded so as to bind him to them until his twenty-first birthday – and, because that birthday happens to be on the extra day of Leap Year (February 29), that means that technically only five birthdays have passed ("When you had left our pirate fold"). Frederic is convinced that he must rejoin the pirates by this logic. (http://en.wikipedia.org/wiki/The_Pirates_of_Penzance) Does the above law prove Gilbert & Sullivan wrong? —Preceding unsigned comment added by GMCW (talk • contribs) 13:06, 4 September 2006 (UTC)
- Not necessarily. English laws are drafted without using the term "birthday", instead always saying 'when a person has reached the age of' X years. Using 'birthday' leaves things open to the Gilbert & Sullivan interpretation. Jess Cully 13:47, 12 October 2006 (UTC)
- Revisiting this - it actually looks like, if this is how the law is worded, someone born on February 29th would reach the age of
1816 on February 28th of a leap year. —Random832 19:48, 19 December 2007 (UTC)
- I've looked, and I can't find anything that says it one way or the other. The issue must have arisen, can anyone born on 29 Feb 1956 in the UK enlighten us? Incidentally, if the voting age is 16 the problem will never occur as the year in question (when the person born on Feb 29 turns 16) will always be a leap year as well, except for the century years not divisible by 400. Walshie79 (talk) 13:28, 20 June 2015 (UTC)
The article states that "a century year is not a leap year unless ... it leaves a remainder of 200 or 600 when divided by 900. Note that years divisible by 4000 will currently not be leap years, despite being divisble by 400." I havent read about this anywhere and it sound to me like nonsense. Unless someone can confirm the facts i will delete them. --AMorris (talk)●(contribs) 05:05, 21 September 2005 (UTC)
Note that years divisible by 4000 will currently not be leap years, despite being divisble by 400. This is patently false. No mention of a longer intercalation period is mentioned in the Papal Bull establishing the Gregorian calendar. No changes have been made since then. I am going to change the article to state that such an idea has been proposed, but not put into action (for among other reasons, it's not immediately clear who has the authority to do so). 18.104.22.168 23:44, 26 November 2005 (UTC)
Probably the United Nations or the International Astronomical Union. Jess Cully 15:12, 12 December 2005 (UTC)
The divisible by 4000 discussion is mildly interesting, but one we'll have to pick up in roughly 1,993 years. If we're still not sure then, we'll have to get back on it around CE 7995. Tzittnan 20:04, 28 February 2007 (UTC)
Birth year query
1900 - Giorgos Seferis, Greek poet and Nobel laureate (d. 1971)—how so, since 1900 wasn't a leap year? Was Greece still following the Julian Calendar? —Preceding unsigned comment added by Copey 2 (talk • contribs) 02:14, 22 May 2006
- Yes, it was. Greece adopted the Gregorian Calendar in 1917. Jess Cully 13:44, 12 October 2006 (UTC)
Leap day is more likely to fall on a Monday than on a Sunday
The article says "a leap day is more likely to fall on a Monday than on a Sunday." Surely this can't be true, can it? Pelago 11:51, 3 March 2006 (UTC)
Yes, it is correct. I didn't believe it either, so I checked!
400 years contain 97 leap days. This is a total of 400*365+97 days, which is 146097 days, which is exactly 20871 weeks. Therefore 29th February is the same day of the week (Tuesday, in fact) in all years divisible by 400. So the 97 leap-days within each 400-year cycle cannot be equally spread over the days of the week. In fact there are 13 Sundays, Tuesdays and Thursdays, 14 Fridays and Saturdays, and 15 Mondays and Wednesdays. —Preceding unsigned comment added by 22.214.171.124 (talk) 18:59, 15 March 2007
I was thinking the very same after reading that paragraph. I think it would be great to update that para in the main text with a bit of your calculation (not to get too geeky, perhaps just the dayofweek counts) to quell the curiosity of people like me --Mortice 19:01, 13 July 2007 (UTC)
- I've revised this, taken out some of the 'you might expect' info and % data and replaced with the counts of days which I think is much more interesting from a browsing point of view --Mortice 20:14, 18 July 2007 (UTC)
I had difficulty believing this, and so checked it out empirically. I first used Visual Basic 6, then tested in in MS Excel 2003. Same results. Here's the latter as an Excel macro:
Sub LeapDays() Dim ic As Integer, iy As Integer, indx As Integer Dim iyFirst As Integer, iyLast As Integer Dim WeekDayOfFeb29(7)As Integer For ic = 15 To 24 'century span 'Zero this out each time through For indx = 1 To 7 WeekDayOfFeb29(indx) = 0 Next indx 'Year span iyFirst = ic * 100 + 1 'start year iyLast = iyFirst + 399 'end year 'Check each leap year For iy = iyFirst To iyLast 'Tally up day of week 'Weekday function returns 1(Sun) to 7(Sat) If IsLeap(iy) Then indx = Weekday("February 29," & Str$(iy)) WeekDayOfFeb29(indx) = WeekDayOfFeb29(indx) + 1 End If Next iy 'Output the counts Debug.Print "From A.D."; iyFirst; "to"; iyLast; ": "; For indx = 1 To 7 Debug.Print WeekdayName(indx); "="; WeekDayOfFeb29(indx); " "; Next indx Debug.Print "" Next ic Stop End Sub Private Function IsLeap(ByVal TheYear As Integer) As Boolean IsLeap = DateDiff("d", "February 28," & Str$(TheYear), "March 1," & Str$(TheYear)) > 1 End Function
From A.D. 1501 to 1900 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 1601 to 2000 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 1701 to 2100 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 1801 to 2200 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 1901 to 2300 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 2001 to 2400 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 2101 to 2500 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 2201 to 2600 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 2301 to 2700 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
From A.D. 2401 to 2800 : Sunday= 13 Monday= 15 Tuesday= 13 Wednesday= 15 Thursday= 13 Friday= 14 Saturday= 14
QED. It should be noted that Microsoft's formulas apply the Gregorian calendar from Jan 1, 100 through Dec 31, 9999, although it's really meaningless before 1752. WHPratt (talk) 17:52, 11 February 2009 (UTC)WHPratt Fixed formatting.WHPratt (talk) 20:29, 2 March 2009 (UTC)
The paragraph on Women proposing on the leap day or year is quaint, but it is presented as having the force of law in some juristdiction. Could we get more specific info on when and where this "tradition" was in practice, with maybe even an example or two? -- 126.96.36.199 17:41, 30 June 2006 (UTC)
Can we have a reference inserted for this? In 1288 the Scottish parliament legislated that any woman could propose in Leap Year. (You know, date, title, section, paragraph, stuff like that!) —Preceding unsigned comment added by 188.8.131.52 (talk) 01:08, 3 February 2007
- for some reason, the relevant information has been deleted in its entirety without discussion. Will add stub info.184.108.40.206 (talk) 03:04, 29 February 2012 (UTC)
Is she really considered a notable death because she was only a school shooting victim, which is not notable to the world, even if it did made major headlines in local areas? The Legendary Ranger 22:11, 30 July 2006 (UTC)
- I've removed the bit about the shooting from events. Fabricationary 22:21, 30 July 2006 (UTC)
Is February 29 really an unusual date?? --220.127.116.11 09:14, 22 December 2006 (UTC)
- It only comes once every 1461 days. You '365ers' aren't too quick, are you? —Preceding unsigned comment added by 18.104.22.168 (talk) 20:32, 8 January 2007
Birth of Richard Ramirez
According to the births on this page, "1960 - Richard Ramirez, American serial killer", however according to the page for Richard Ramirez, he was born February 28, 1960 - this is also cited (but the cited link requires registration. Looks like quite an infamous person over in the US, so can anyone confirm one date over the other? --Woodgreener 15:46, 21 January 2007 (UTC)
feb 29 not 60th AND 61st day
- I have fixed the error, which is in a template, by removing the template. I have written to the template's last edditor to advise of the problem. --Drappel 16:05, 20 May 2007 (UTC)
Do any countries use this rule as a basis for legal time periods, i.e. count a February 28th birthday in a leap year as the 27th in a common year, so on back to the 25th (24th)? —Random832 19:45, 19 December 2007 (UTC)
May I suggest that Ms. Lydia Dunn, DBE to be added under the Birthdays section? She played an important role in politics of Hong Kong in the 80s to early 90s. —Preceding unsigned comment added by 22.214.171.124 (talk) 14:26, 29 February 2008 (UTC)
When this day falls in opening
Today I added the following sentence to the opening: 'In general, in even decades (1980s, 2000s, etc) February 29 occurs in the 0, 4 and 8 years, and in odd decades (1990s, 2010s, etc) February 29 occurs in the 2 and 6 years. The exception to this is years that are divisible by 100 but not by 400 (1900, 2100), in which case February 29 does not occur.'
User:Grouf soon reverted my edit saying it was confusing. I'm forced to agree, but still I think there should be an explanation of the years when February 29 occurs. --Philip Stevens (talk) 15:05, 29 February 2008 (UTC)
- It is explained in the first sentence: ...occurs only every four years, in years evenly divisible by 4...with the exception of century years not divisible by 400... That is simple and straight-forward, anything more then that causes confusion. Grouf (talk • contribs) 15:19, 29 February 2008 (UTC)
Happy Leap Day
Based on the hard line on notability criteria involving day-of-the-year articles, this following events should probably not be in this article. I am curious to know why these should remain in the article. I am trying to get a better gauge of what is and what is not notable here. Kingturtle (talk) 22:15, 29 February 2008 (UTC)
- 1712 - February 29 is followed by February 30 in Sweden, in a move to abolish the Swedish calendar for a return to the Old style.
- 1720 - Queen Ulrika Eleonora of Sweden abdicates in favour of her husband, who becomes King Frederick I.
- 1864 - American Civil War: Kilpatrick-Dahlgren Raid fails
- 1892 - St. Petersburg, Florida is incorporated.
- 1916 - Child labor: In South Carolina, the minimum working age for factory, mill, and mine workers is raised from twelve to fourteen years old.
- 1932 - TIME magazine features eccentric American politician William "Alfalfa" Murray on its cover after Murray stated his intention to run for President of the United States.
- 1936 - Baby Snooks, played by Fanny Brice, debuts on the radio program The Ziegfeld Follies of the Air.
- 1956 - U.S. President Dwight D. Eisenhower announces to the nation that he is running for a second term.
- 1960 - An earthquake in Morocco kills over 3,000 people and nearly destroys Agadir in the southern part of the country.
- 1960 - Family Circus makes its debut.
- 1964 - In Sydney, Australian swimmer Dawn Fraser sets a new world record in the 100-meter freestyle swimming competition (58.9 seconds).
- 1972 - Hank Aaron becomes the first player in the history of Major League Baseball to sign a $200,000 contract.
- 1980 - Gordie Howe of the then Hartford Whalers makes NHL history as he scores his 800th goal.
- 1996 - Novelist Joan Collins is awarded US $1 million from Random House for breach of contract.
- 1996 - A Peruvian Boeing 737 crashes in the Andes, killing 123 people.
- 2000 - Six year old Dedrick Owens shoots and kills Kayla Rolland, also six years old, at Theo J. Buell Elementary School in Mount Morris Township, Michigan.
Typo in Birthday listing
The listing of David Beattie, born Feb 29 1924, has a mis-spelling of "Governor-General"
Why is it called "LEAP"?
This question must be answered on this page. Why is it called "LEAP"?
- Its name arises from the way the day of the week of a fixed day of the year behaves. Let's look at July 4 as an example. Let's start out with July 4, 2000, which is a Tuesday. What is July 4, 2001?? The answer is a Wednesday. July 4, 2002 is a Thursday and July 4, 2003 is a Friday. How about July 4, 2004?? The pattern suggests it should be a Saturday, but it is a Sunday because of 2004's extra day. Thus, the date has "leapt over" Saturday. Georgia guy (talk) 22:17, 8 May 2008 (UTC)
Excel Day Count
The effect of the "included" 1900-02-29 on Excel dating (also Delphi) is alluded to in another part of the discussion, without adequate reference. I consider it worth mentioning, briefly but with carefully-ascertained facts, in the main article. 126.96.36.199 (talk) 19:48, 19 May 2008 (UTC)
Divisible by 900
Discussion contains a mention of replacing the "divisible by 400" rule with a "divide by 900, remainder 200 or 600" rule. That belongs, I believe, to the Soviet calendar of about 1930, and to the Greek Orthodox Church. I suggest that, if those can be confirmed, a brief statement in the main Article would be appropriate. 188.8.131.52 (talk) 19:56, 19 May 2008 (UTC)
Three paydays in February?
Someone may find this interesting enough to work it into the article.
How often does February 29 occur on a Friday? Using a variation on a method that I described earlier on this page . . .
Private Sub Feb29Fri() For iy = 1800 To 2100 If IsLeap(iy) Then If WeekDay("February 29," & Str$(iy)) = vbFriday Then Debug.Print Format$("February 29," & Str$(iy), "Long Date") End If End If Next iy End Sub Private Function IsLeap(ByVal TheYear As Integer) IsLeap = DateDiff("d", "February 28," & Str$(TheYear), "March 1," & Str$(TheYear)) > 1 End Function
Friday, February 29, 1828 Friday, February 29, 1856 Friday, February 29, 1884 Friday, February 29, 1924 Friday, February 29, 1952 Friday, February 29, 1980 Friday, February 29, 2008 Friday, February 29, 2036 Friday, February 29, 2064 Friday, February 29, 2092
It should occur once every 28 years. (The long gap between 1884 and 1924 has to do with 1900 not being a leap year.)
Only in these particular months does February have five Fridays. Now, assuming that workers are paid on alternate Fridays, only in these years can a worker receive three paychecks in February (on the 1st, 15th and 29th).
However, roughly half the employers will be out of step with the other half, and these will have paydays on the 8th and 22nd. Therefore, a typical worker has only a one-in-56 chance of a three-payday February in his working life. WHPratt (talk) 16:14, 23 April 2009 (UTC)
- It's really not that interesting. And your assumption that workers are paid on alternate Fridays is heavily flawed. None of the jobs I've ever held have paid on Fridays. Many employers pay semi-monthly instead of biweekly; many employers pay weekly instead of biweekly, at least to certain categories of employees. Still others pay on a monthly basis. I'm writing this in 2012 and get paid on Wednesdays, which means that for me this is a three-payday month.184.108.40.206 (talk) 19:32, 17 January 2012 (UTC)
- Wasn’t meant to illuminate anything about workers and their pay, but just to put a human face on the quirky statistic, to show how rare an event is five of any particular weekday in February. It could apply to other situations, e.g., how often does a church have to prepare for five Sundays in February.WHPratt (talk) 13:31, 20 January 2012 (UTC)
- 12:34, 22 February 2008 Steel (talk | contribs) protected February 29 (Socking anon [edit=autoconfirmed:move=autoconfirmed] (expires 12:34, 21 March 2008 (UTC)))
- 14:20, 6 April 2008 Steel (talk | contribs) protected February 29 (Vandalism and socking anon [edit=autoconfirmed:move=autoconfirmed])
- 16:01, 15 June 2008 Wizardman (talk | contribs) changed protection level for "February 29" (No need to move. using TW [move=sysop])
- 22:12, 15 June 2008 Wizardman (talk | contribs) changed protection level for "February 29" (Re-semiprotecting after finding out why it was originally semi'd. [edit=autoconfirmed:move=sysop])
After over 18 months, I'd like to review this to see if it's still necessary. As well as welcoming comments from regular editors I've contacted Steel, the protecting admin. --TS 07:01, 4 October 2009 (UTC)
"In England and Wales a person born on February 29 legally reaches the age of 18 or 21 on February 28 of the relevant year(though 18 year-olds can't buy tobacco products – or a 21 year old can't buy alcohol – until March 1)"
Citation has been required for the above statement for months now; also age to purchase alcohol in the UK is 18... Someone should delete. —Preceding unsigned comment added by 220.127.116.11 (talk) 10:27, 16 September 2010 (UTC)
What the 24 hour February 29th rotation does
The story of the current cycle began on Mar 1st 2008 when daily rotation and orbital motion started in sync,as the orbital cycle of the Earth around the Sun is 365 days 5 hours 49 minutes,the orbital cycle ended at roughly 6 AM Mar 1st 2009 whereupon a new orbital cycle of 365 1/4 days began and ended at 12 noon Mar 1st 2010,As there are 365 days and rotations between Mar 1st and Feb 28th each year,the orbital cycle drifts ahead through Mar 1st each non-leap year in increments of 6 hours so that by Mar 1st 2011,the orbital cycle was ahead by a full 18 hours in ending at 6 PM Mar 1st 2011.At the end of Mar 1st 2012 the orbital cycle is ahead by almost a full 24 hours so that the extra 24 hours of rotation on February 29th returns the daily and orbital cycles back into sync whereupon the orbital cycle ends the next year at 6 AM Mar 1st 2013.To the nearest rotation,the correspondence between 1461 days and 4 years with 1461 rotations and 4 orbital circuits is the most familiar in all science through the leap day correction of February 29th,a small but dominant group of people have managed to propose 1465 rotations in 4 orbital circuits thereby disturbing what is a jewel of human timekeeping and the dynamics from which it came.Gkell1 (talk) 14:52, 5 January 2012 (UTC)
- To the extent that the last sub-sentence (beginning "a small but dominant") makes sense, it seems to deal with the difference between the mean solar day and the sidereal day or stellar day. However, it has nothing to do with this article. — Arthur Rubin (talk) 03:44, 21 January 2012 (UTC)
The leading article for an extra day at the end of 4 years is exceptionally weak.The first written account of the need for an extra day to keep the number of days in line with seasonal events is based on the fact that if the ancients stayed with a system of a continuous 365 days they would have found events such as the flooding of the Nile drifting through the seasons.They watched for the seasonal return of the star Sirius to the same spot in the sky and noticed that it returns to the same spot after every 1461 days so they tacked on an extra day after the 4 years of 365 days - "But that these feast days shall be celebrated in definite seasons for them to keep for ever, and after the plan of the heaven established on this day and that the case shall not occur, that all the Egyptian festivals, now celebrated in winter, shall not be celebrated some time or other in summer, on account of the precession of the rising of the Divine Sothis [Sirius] by one day in the course of 4 years, and other festivals celebrated in the summer, in this country, shall not be celebrated in winter, as has occasionally occurred in past times, therefore it shall be, that the year of 360 days and the 5 days added to their end, so one day as feast of Benevolent Gods [the pharaoh and family] be from this day after every 4 years added to the 5 epagomenae before the New Year, whereby all men shall learn, that what was a little defective in the order as regards the seasons and the year, as also the opinions which are contained in the rules of the learned on the heavenly orbits, are now corrected and improved" Canopus Decree
The point is that the Egyptians began with 1461 days corresponding to 4 years whereas the description in the main article tries to begin with 365 1/4 days and work things out from there,in this case the ease of description for Feb 29th by explaining how the Egyptians approached it requires an alteration in the main article insofar as the reduction of 1461 days in 4 years to 365 1/4 days in 1 years distracts from the reasoning which formats the calendar as 3 years of 365 days and 1 year of 366 days using only the 1461 day value in tandem with the appearance of Sirius to the same point in the sky.Gkell1 (talk) 13:14, 21 February 2012 (UTC)
- Beginning with the article being weak, I whole-heatedly agree. But I don't feel this page is where the in depth article belongs. 365 pages of similar formatting and 1 page breaking format completely just doesn't "feel" right. Something makes me uncomfortable about that personally. The paradox of time itself would certainly make for an extensive article surrounding leap days. I feel that for this page, a simple, brief explanation fits into the DOY format much better.
- I also think that for the vast majority of folks, simple and brief is much better than the mind-numbing text that all too often accompanies articles related to time differential and celestial mechanics. I myself am deeply into orbital periods, zeniths, solar time v. terrestrial time, the equation of time, julian conversian, obliquity, inclination, etc, etc. Gotta know all that stuff to be reasonably adept at what goes on off planet and for building precision simulations. For me, an in depth article would be awesome. But not here. There's no way we could just stop with the Egyptions. Ken Tholke (talk) 14:33, 21 February 2012 (UTC)
The explanation the Egyptians give in the Canopus Decree for an extra day is almost self-explanatory in terms of references used and why they found it necessary to institute the additional day but from a standpoint of 1461 days in 4 years and this perspective should take precedence over the article that starts with 365 1/4 days in a year as that is merely extraneous to the original observation.The original approach by the Egyptians is more concise and easier for the student or an interested adult to understand and especially the dramatic event of the flooding of the Nile and the seasonal appearance of Sirius. Immediately launching into the Gregorian correction is unhelpful and that space could be given to the broad issue of why the extra day prevents the drift of seasonal events,needless to say,and despite appearance,it is a large undertaking to straighten out the historical and technical details,at least to make it interesting and enjoyable for the student. Gkell1 (talk) 20:07, 21 February 2012 (UTC)
- This article is just one of a 366-article series that constitutes a kind of day-book for the Gregorian calendar. It's hardly the "leading article for an extra day at the end of 4 years" -- Leap year, Gregorian calendar or Julian calendar are surely more appropriate. But IMO issues about the Canopic reform of the Egyptian calendar are best discussed in the Canopus Decree article.
- A couple of points of detail: The Canopic reform was not really an Egyptian reform. It was a reform of the Egyptian calendar imposed by Egypt's Greek rulers, the Ptolemies, based on Greek astronomical knowledge, known since Eudoxus and Cleostratus. Also, the description of the leap day as an accumulation of quarter days over four years is very clearly spelled out in Macrobius' description of the Julian reform, so this is how the Romans understood it, and is surely how Sosigenes explained it to them. --Chris Bennett (talk) 02:44, 24 February 2012 (UTC)
The requirement for an extra day after 4 consecutive periods of 365 days is bound to the observation that Sirius disappears into and emerges out of the glare of the central Sun,it happens to be one of those spectacular astronomical events which clearly demonstrates the sweep of the Earth as certain stars in turn disappear and emerge from behind the Sun as the Earth travels around the Sun in its orbital circuit.It is an absolutely great way for students to learn about the orbital motion of the Earth and how the great astronomers in antiquity noticed that it takes Sirius an extra day after every 4 cycles of 365 days to return from behind the Sun's glare.It is therefore appropriate to include the founding historical description of 1461 days in tandem with the seasonal event of the flooding of the Nile to demonstrate how they formatted the system to the familiar 365/366 day format rather than jump straight into the overcompensation which led to the Gregorian correction and which is something that is exceptionally difficult to master and explain. If the need for Feb 29th broadens acceptance of the Earth's orbital motion in an enjoyable way through the original observation of Sirius then who can object to its inclusion in the main article as it falls within the understanding of an interested student.Gkell1 (talk) 15:33, 24 February 2012 (UTC)
Sunday 29/2/00 (In U.S. writting: 2/29/00 ) appears once per... how much time? 2800 years? And once per how much time it crosses the Jewish Calendar Adar 6th ? 53 200 years (2800*19) ? 18.104.22.168 (talk) 17:12, 3 December 2011 (UTC)
In the Gregorian calendar, February 29 never falls on a Sunday in a century year. However, if years divisible by 4000 are not leap years, then February 29, 8400 will be a Sunday. GeoffreyT2000 (talk) 16:39, 1 March 2015 (UTC)
- You mean, kind of like the days of the month could have been designated 1, 2...23, 23A, 24...28?? Georgia guy (talk) 14:25, 14 February 2012 (UTC)
- The leap day (or bissextile day) was inserted after February 23 in a manner of speaking since the 3rd century, see Julian calendar#Intercalation. In Latin, the days of a month were counted backward from three cardinal days, the nones, ides, and kalendae. In this case, the bissextile day was designated "ante diem bis sextum Kalendas Martias" or "the second sixth day before March 1" (counted inclusively). In Roman numerals, the last few days of a bissextile February and March 1 were designated: VI, bis VI, V, IV, III, pridie, kalendas. When the days of a month began to be numbered consecutively during the Middle Ages, these days were designated 23, 24, 25, 26, 27, 28, 29, 1. Simply numbering the days consecutively caused the leap day to shift to February 29. The fifth day or Feb 24 was called St. Matthias day by the Roman Catholic Church, so when numbered consecutively it was shifted to Feb 25 in leap years so that it would continue to be on V Kal. Mar. In 1969 the Roman Catholic Church changed his feast day to May 14. — Joe Kress (talk) 20:04, 14 February 2012 (UTC)
- The Gregorian leap day in the canons associated with the 1582 papal bull Inter gravissimas (written in Latin) is specified by "duplex" next to "vj 24", that is, sixth kalends or 24 February is doubled. However, the 1750 British Calendar act does not double 24, instead it adds day 29 to the end of February. Thus, the article is correct for the Gregorian calendar used by English speaking Great Britain and its colonies. — Joe Kress (talk) 07:55, 19 February 2012 (UTC)
- You might say that some people consider the 29th to be the leap day whilst others stick to the traditional 24th. These are just two different perspectives on what is essentially the same calendar (or calendars (Julian and Gregorian)). There are other calendars out there though. The Thai lunar calendar mentioned above has leap days which are not 29 Feb as do the Ethiopian calendar, Zoroastrian calendar and French Republican Calendar, to name a few, then there are proposed calendars such as the International Fixed Calendar, Positivist calendar and World Calendar, fictional ones such as the Tolkien's Middle-earth calendars and extraterrestrial ones such as the proposed Martian Darian calendar. It makes no sense to have "leap day" redirect here. Jimp 09:23, 19 March 2014 (UTC)
Misinterpretation of New Zealand Law
New Zealand law is misinterpreted in the February_29#Births. The statement that:
- In cases of New Zealand citizens, the Parliament has decreed that if a date of birth was February 29, in non-leap years the legal birth date shall be the preceding day, February 28. This is affirmed in §2(2) of the Land Transport Act 1999.
Totally misrepresents the applicable New Zealand law. The cited legislation does not exist! The correct legal reference is §2(2) Land Transport (Driver Licensing) Rule 1999 and is correctly linked in the footnote. However, this is a regulation or rule issued under the Land Transport Act 1998 (not 1999) by the Ministry of Transport, not the Pariament, but the Executive branch of Government. All is says is that for the purposes of administering Driver Licensing if a Birthday, or other (anniversary) date, that falls on 29 February in a leap year then in non-leap years it falls on 28 February, i.e. it still falls on the last day of February, not the first day of March. Because a person must be at least 16 years old to apply for a driver licencse, this clause does not affect a person born on 29 February making an application on their 16th Birthday, which would also be 29 February. Where it does impact is later in life when from 75years old licences expire on a person's birthday. Under common law this would mean that a person whose birthday fell on 29 February would have their licence expire on 1 March in non-leap years and on 29 February in leap years. This clause actually results in the licence expiring one day earlier in non-leap years so that a licence held by a person with a birthday on 29 February would always expire at the end of the last day of February, rather than continuing into the first day of March.
The subsequent two references that in New Zealand people born on 29 February have a legal birthday on 28 February is also incorrect. In the first instance, Taiwanese law does not apply to New Zealand, so including New Zealand in the sentence is incorrect. In the second instance, New Zealand case law (Re an Infant (1936) 31 MCR 42) and legislation, section 35(2) of the Interpretation Act 1999, indicates that the date of birth is not included when counting the number of years to the birthday in question when determining a person's age. Thus a person born on 29 February will be one year old on 1 March because a leap year has 366 days according to the Calendar (New Style) Act 1750 (24 Geo 2 c.23) and subsequent case law. I will therefore amend the New Zealand reference.
Also , I note there is no explanation (or citation) for why a person born on 29 February would have a birthday on 28 February, rather than 1 March in the United States. - Cameron Dewe (talk) 12:09, 11 June 2013 (UTC)
The following century years skip February 29.
1700 1800 1900
2100 2200 2300
2500 2600 2700
2900 3000 3100
3300 3400 3500
3700 3800 3900
4100 4200 4300
4500 4600 4700
4900 5000 5100
5300 5400 5500
5700 5800 5900
6100 6200 6300
6500 6600 6700
6900 7000 7100
7300 7400 7500
7700 7800 7900
8100 8200 8300
8500 8600 8700
8900 9000 9100
9300 9400 9500
9700 9800 9900 GeoffreyT2000 (talk) 19:08, 28 March 2015 (UTC)
- Yes, this is a simple consequence of the 400 rule: century years not divisible by 400 aren't leap years in the Gregorian calendar. This list conveys no further information. -- Elphion (talk) 02:51, 29 March 2015 (UTC)