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Why Do We Need Leap Days?
Life Little Mysteries ^ | 3/2/2012 | Alexey Repka

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.

(Excerpt) Read more at lifeslittlemysteries.com ...


TOPICS: Chit/Chat; Science
KEYWORDS: nist; science; trivia
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To: Cyber Liberty

That sounds like a deal. Just send the invite


61 posted on 03/03/2012 8:50:26 PM PST by U-238
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To: Cyber Liberty

RSVP is important


62 posted on 03/03/2012 8:50:58 PM PST by U-238
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To: U-238

I expect if you blink you’ll miss it. Sort of like my home town....


63 posted on 03/03/2012 9:12:01 PM PST by Cyber Liberty ("If the past sits in judgment on the present, the future will be lost." --Winston Churchill)
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To: Cyber Liberty

I will look for your invite.


64 posted on 03/03/2012 9:21:33 PM PST by U-238
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To: Boogieman

There is no rational controversy that the obvious disconnection between rotational and orbital periods points to randomness rather than design. I believe I have adequately backed up that assertion with the numbers. If that is either too difficult for you to understand or if you choose to assert a position where that disconnection points to design, I cannot help you further.


65 posted on 03/04/2012 12:24:33 AM PST by muir_redwoods (No wonder this administration favors abortion; everything they have done is an abortion)
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To: Boogieman

And if the ratio between orbital and rotational periods were the same for every planet the way pi is constant for every circle you’d have a valid point.


66 posted on 03/04/2012 12:32:09 AM PST by muir_redwoods (No wonder this administration favors abortion; everything they have done is an abortion)
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To: muir_redwoods

I don’t assert the position that it points to design, and to my knowledge, nobody else does. It’s not evidence of either design or randomness, it’s just a simple ratio determined by the laws of physics. Now, the laws of physics that determine what the ratio is, I’d say those are evidence of design, but that’s a whole other argument.


67 posted on 03/04/2012 8:50:59 AM PST by Boogieman
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To: muir_redwoods

“And if the ratio between orbital and rotational periods were the same for every planet the way pi is constant for every circle you’d have a valid point.”

That is just simplistic thinking. The ratio of the orbital and rotational periods are not all determined by as simple a formula as the ratio of a circle, but they are all determined by the constant physical laws, which can be expressed in a more complex formula. Is a more complex formula evidence of randomness?


68 posted on 03/04/2012 8:55:17 AM PST by Boogieman
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To: muir_redwoods

Besides which, my original point for making the comparison to Pi, was to show that having an irrational result for the ratio of two values, was not evidence of randomness. So, simply because the ratio of the orbit to the rotation doesn’t equal 365.0 is not evidence of any kind of randomness in their correlation.


69 posted on 03/04/2012 8:57:49 AM PST by Boogieman
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To: U-238

I can’t promise a ping. My memory is poor. You know, memory is the second thing to go as you get older. I forget what the first thing is...With any luck, it’ll get enough posts for you to see it, but as I said, if you blink you’ll miss it.

:^)


70 posted on 03/04/2012 9:02:19 AM PST by Cyber Liberty ("If the past sits in judgment on the present, the future will be lost." --Winston Churchill)
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