Leap Day

[kstar]

What if you were born in a leap year on February 29th?

It would be cool and kind of suck.

I think it's worth a thread.

Leap year/day interesting facts, anyone?

Best,

Kurt

[slodave]

I wasn't born on the 29th, but grew up with someone who did. Not really a big deal. They just celebrated on the 28th the other years.

[kstar]

I never knew it was so complex.

Time for a more modern calendar?

From Wiki:

Gregorian calendar

In the Gregorian calendar, the current standard calendar in most of the world, most years whose division by 4 equals an integer are leap years. In a leap year, the month of February has 29 days instead of 28. Adding an extra day to the calendar every four years compensates for the fact that a solar year is almost 6 hours longer than 365 days.

However, some exceptions to this rule are required since the duration of a solar year is slightly less than 365.25 days. Years which are evenly divisible by 100 are not leap years, unless they are also evenly divisible by 400, in which case they are leap years.[1][2] For example, 1600 and 2000 were leap years, but 1700, 1800 and 1900 were not. Going forward, 2100, 2200, 2300, 2500, 2600, 2700, 2900, and 3000 will not be leap years, but 2400 and 2800 will be. By this rule, the average number of days per year will be 365 + 1/4 − 1/100 + 1/400 = 365.2425, which is 365 days, 5 hours, 49 minutes, and 12 seconds.

The Gregorian calendar was designed to keep the vernal equinox on or close to March 21, so that the date of Easter (celebrated on the Sunday after the 14th day of the Moon that falls on or after 21 March) remains correct with respect to the vernal equinox.[3] The vernal equinox year is about 365.242374 days long (and increasing), whereas the average year length of the Gregorian calendar is 365.2425.

The marginal difference of 0.000125 days means that in around 8,000 years, the calendar will be about one day behind where it is now. But in 8,000 years, the length of the vernal equinox year will have changed by an amount which cannot be accurately predicted (see below). Therefore, the current Gregorian calendar suffices for practical purposes, and Herschel's correction (making 4000 AD not a leap year) will probably not be necessary.

Best,

Kurt

[kstar]

Originally Posted by slodave

I wasn't born on the 29th, but grew up with someone who did. Not really a big deal. They just celebrated on the 28th the other years.

Your friend was a "leapling".

More from Wiki:

Birthdays

A person born on February 29 may be called a "leapling". In common years they usually celebrate their birthdays on 28 February or 1 March.

For legal purposes, their legal birthdays depend on how different laws count time intervals. In Taiwan, for example, the legal birthday of a leapling is 28 February in common years, so a Taiwanese leapling born on February 29, 1980 would have legally reached 18 years old on February 28, 1998.
“ If a period fixed by weeks, months, and years does not commence from the beginning of a week, month, or year, it ends with the ending of the day which proceeds the day of the last week, month, or year which corresponds to that on which it began to commence.　 But if there is no corresponding day in the last month, the period ends with the ending of the last day of the last month.[10] ”

In some situations, March 1 is used as the birthday in a non-leap year since it then is the day just after February 28.

There are many instances in children's literature where a person's claim to be only a quarter of their actual age turns out to be based on counting only their leap-year birthdays. A similar device is used in the plot of the Gilbert and Sullivan operetta The Pirates of Penzance.

Best,

Kurt

[Hugh R]

Dated a girl who was born on leap day for a while. Nothing like having sex with women whose just had her fifth birthday . Wait, now think about it... leap year every four years, her B-day and she was actually 20, Ok, Ok!!!

[Porsche-O-Phile]

Google has a cute picture on its homepage to celebrate:



Where's frogger?

[Tobra]

Originally Posted by slodave

I wasn't born on the 29th, but grew up with someone who did. Not really a big deal. They just celebrated on the 28th the other years.

knew a chick born on Feb 29, well she is Dr Chick now, but that is what she did.

Not 5 year old Hugh, fifth birthday

[Hugh R]

Originally Posted by Tobra

Not 5 year old Hugh, fifth birthday

Whew, thanks, your right! I feel so much better. In fact I'm going to edit my post to reflect that, even though you've copied it.

[kstar]

There's even a leap second - here's a bit about it, again from Wikipedia:

Announcement of leap seconds

The International Earth Rotation and Reference Systems Service (IERS) announces the insertion of a leap second whenever the difference between UTC and UT1 approaches 0.6 s, to keep the difference between UTC and UT1 from exceeding ±0.9 s. The announcement appears in IERS "Bulletin C", typically published every six months.

After UTC 23:59:59, a positive leap second at 23:59:60 would be counted, before the clock indicates 00:00:00 of the next day. Negative leap seconds are also possible should the Earth's rotation become slightly faster; in that case, 23:59:58 would be followed by 00:00:00. Leap seconds occur only at the end of a UTC month, and have only ever been inserted at the end of June 30 or December 31. Unlike leap days, they occur simultaneously worldwide; for example, the leap second on 31 December 2005 occurred at 23:59:60 UTC. This was 6:59:60 p.m. U.S. Eastern Standard Time and 0:59:60 a.m. on 1 January, 2006 Central European Time.

Historically, leap seconds have been inserted about every 18 months. However, the Earth's rotation rate is unpredictable in the long term, so it is not possible to predict the need for them more than six months in advance. Between January 1972 and December 2005, the IERS gave instructions to insert a leap second on 23 occasions. The interval between 1999-01-01 and 2005-12-31 was the longest period without a leap second since the system was introduced.

Leap seconds are also not included directly in GPS time, although a regularly broadcast message notes how far GPST and UTC are apart.

Some time signal broadcasts give voice announcements

Best,

Kurt

[911Rob]

my daughter missed it by one day!
Turned 14 today, my baby:

[Hugh R]

I'm going to burn in hell for that post. Or at worst when I run for POTUS, someone will drag up that post about fifth birthdays! I'm hosed I tell you, effing hosed! Fiftieth birthday, Yah! that's what I meant, it was a typo!!!

[kstar]

More cool stuff about time - emphasis added in bold:

Atomic clocks, the Earth and relativity

Atomic clocks are very precise and have nearly no clock drift. The rotation of the Earth itself actually has much more clock drift (less accuracy) than modern atomic clocks. Thus to keep the Coordinated Universal Time (UTC) in line with the Earth's rotation some years a leap second has to be added.

As Einstein predicted, relativistic effects can also cause clock drift due to time dilation. This is because there is no fixed universal time, time being relative to the observer. Special relativity describes how two clocks held by people in different inertial frames (i.e. moving with respect to each other but not accelerating or decelerating) will each appear to tick more slowly to the other person.

In addition to this, general relativity gives us gravitational time dilation. Briefly, a clock in a higher gravitational field (e.g. closer to a planet) will appear to tick more slowly. People holding these clocks would agree on which clock appeared to be going faster.

Note that it is time itself rather than the function of the clock which is affected. Both effects have been experimentally observed.

Time dilation is of practical importance. For instance, the clocks in GPS satellites experience this effect due to the reduced gravity they experience (making their clocks appear to run more quickly than those on Earth) and must therefore incorporate relativistically corrected calculations when reporting locations to users. If special relativity were not accounted for, the reported location would be off by about 1 km.[1]

Source: http://en.wikipedia.org/wiki/Clock_drift

Best,

Kurt

[Hugh R]

Rob, way cute, I'd think twice about posting pictures of your beautiful, and I mean beautiful, daughter on the internet! Its not just "us" you know!!

[aigel]

If you are a salaried employee, you are working for free tomorrow. That sucks. I'll leave early.

George

[slodave]

Originally Posted by aigel

If you are a salaried employee, you are working for free tomorrow. That sucks. I'll leave early.

George

Dammit! I work for myself. Note to self - pay me for tomorrow...

Naw, I'd rather sleep in!

[red-beard]

Originally Posted by aigel

If you are a salaried employee, you are working for free tomorrow. That sucks. I'll leave early.

George

Not so fast. This is a truly intersting month. How many Februarys do you have, where you're paid every 2 weeks, and get 3 paychecks in the month!

[austin552]

Originally Posted by Hugh R

I'm going to burn in hell for that post. Or at worst when I run for POTUS, someone will drag up that post about fifth birthdays! I'm hosed I tell you, effing hosed! Fiftieth birthday, Yah! that's what I meant, it was a typo!!!

It takes quite a man to admit he has a problem Hugh, but now your going to have to register and live under a bridge with the others. I made the necessary calls to get the ball rolling. I hope you get help. Best of luck.

[cairns]

How much for the little girl?

[legion]

We are paid bi-weekly on Fridays where we work. Today is the third paycheck in February. IIRC, the next time this will happen is in 2064.

[mjohnson]

Today is my grandmother's 22nd.

Let me tell you, her 21st was wild, but at her age she didn't do TOO many shots.

She's super cool about it - last year my bday card was late by a day. She said that she considered it 364 days early for her real birthday.

mike in some other LA