Skip to comments.Why Do We Need Leap Days?
Posted on 03/03/2012 1:22:50 AM PST by U-238
Most years, the calendar hops straight from Feb. 28 to Mar. 1. But in almost all years whose numerical value is divisible by four, such as 2012, an extra "leap day" gets tacked on the end of the second month. Cue, today's date: Feb. 29.
The extra day must be added to every fourth calendar year in order to keep our Gregorian calendar synchronized with actual astronomical measures of the passage of time. According to the National Institute of Standards and Technology (NIST), the length of Earth's year as in the time it takes for the planet to complete one revolution around the sun is not a clean 365 days, but rather 365.2422. Adding an extra day to one-fourth of calendar years compensates for the buildup of partial days.
However, because the astronomical year isn't exactly 365.25 days long, but a hair shorter, the normal leap year schedule is a slight over-compensation. To scale back the full-day leaps and keep the calendar right on track, some century years (years with double zeroes at the end) are not leap years. The rule dictates that only century years which are divisible by 400, such as the year 2000, contain leap days. The numbers 1900, 1800 and 1700 aren't divisible by 400, and so those years were not leap years.
Altogether, the 400-year leap year cycle ensures that Earth is as close as possible to the same point in its orbit in consecutive calendar years. Any further errors that accumulate are corrected when needed through the addition of a leap second onto the last minute of either June or December. During leap seconds, the Coordinated Universal Time follows the sequence 23h 59m 59s - 23h 59m 60s - 00h 00m 00s.
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Because if we didn’t there would be no Leap Nights?
Say that again.
This is an entertaining way to explain it.
And without those leap nights, many married men would be celibate.
The motivation of the Catholic Church to adjusting the calendar was the celebration of Easter. The Council of Trent approved the plan to correct the errors in the calendar.First, it was necessary to approximate the correct length of a solar year.The second stage was to devise a model based on the approximation which would provide an accurate yet simple, rule-based calendar
Before the Gregorian calendar, most countries relied on the Julian calendar, which was introduced by Julius Caesar in 45 BC. It was in common use until the 1500s. The Julian calendar creates an error of 1 day every 128 years.
The Gregorian calendar was proposed by Aloysius Lilius, a physician from Naples, and adopted by Pope Gregory XIII in accordance with the instructions from the Council of Trent (1545-1563) to correct for errors in the older Julian calendar. It was decreed by Pope Gregory XIII in a papal bull on February 24 1582. This bull was named Inter Gravissimas after its first two words.
We need leap year because there is no connection whatsoever between the rotation of the earth and it’s orbit around the sun. Remember that the next time someone starts feeding you the Cosmic Watchmaker line.
William Paley was one of the first people for the Cosmic Watchmaker arguement
Although Cicero, Voltaire and René Descartes, for example, used timepieces in arguments regarding purpose
Well, that’s a non sequiter if ever I heard one.
I can explain it for you but I can’t understand it for you. The gears in a watch sync up pretty closely. They all relate to each other in the manner in which they turn. There’s no need for a “leap gear” in a watch. See?
Because fireworks look like crap in a blizzard?
People born on Leap Day get squat for birthday presents three years out of four. They should be allowed to live four times as long. Pancake house is full on Leap Day for some reason. I went there Wednesday and the lines were out the door. Yet on Thursday, I got right in.
So I can have a birthday, newbie !
Yes, we know THAT, but why February and not, say June 31st or July 32nd?
Those are months we wouldn't mind being longer - living in New England, I would be Ok with a shorter February, maybe 21 days....
And how did you deduce that there exists no connection between the two?
I just want to know how I can add that six hours into my sleep time?
That’s funny. February was probably picked because it is the shortest month.
In the Chinese calendar leap months, “embolismic” months, almost always occur in the summer. Oriential wisdom, or the incidental consequence of Kepler’s second law? I pick the latter.
Most people are not aware that the Gregorian Solar Calendar has a sidekick lunar calendar, which is even more accurate than the Gregorian. The ecclesiastic age of the moon does not change on February 29, so that in both common years and leap years, the age of the moon on January 1 is the same as the age on March 1. This simplifies the computation of the date of Easter. The length of an ecclestiastic lunation alternates between 29 and 30 days, (with centuries scale corrections) so that March 1st is exactly 59 days after January 1st, if we do not count February 29 and therefore has the same lunar age.
In the Gregorian calendar, short months always follow long months, except for August (see, they were thinking about you), so that the lunar phase is retarded by about one day on the same day month to month except in September, where it slips about two days and in March, where it exactly follows January.
Say, are you related to that lady who was against daylight saving time because the extra hour of sunlight would burn her grass?