This event only
happens once every four years hence the
difficulty.
WHEN: 2-29-2012
TIME: 11:30am - 1:00pm (1.5
Hours)
WHERE: Applebee's 1281 KNAPP RD - North Wales
Pa. (Route 309 & Knapp Road)
WHY: It's a once in
every FOUR years chance to meet your fellow cachers on this
date.
This is the Second in the series
of the Original Leap Event I have hosted. I'm looking forward to
those who attended 4 years ago and those who will make this there
first for this reoccurring event.
As of this writing the property
offers an All You Can Eat Soup and Salad with reasonable pricing
among there well know menu items.
More details as the date grows
closer.
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Why do we need
leap year?
The Gregorian calendar,
which now serves as the standard calendar for civil use throughout
the world, has both common years and leap years. A common
year has 365 days and a leap year 366 days, with the extra, or
intercalary,
day designated as February 29. A leap year occurs every four years
to help synchronize the calendar year with the solar year, or the
length of time it takes the earth to complete its orbit about the
sun, which is about 365¼ days.
The length of the
solar year, however, is slightly less than 365¼ days—by about
11 minutes. To compensate for this discrepancy, the leap year is
omitted three times every four hundred years.
In other words, a
century year cannot be a leap year unless it is divisible by 400.
Thus 1700, 1800, and 1900 were not leap years, but 1600, 2000, and
2400 are leap years.
What are your
chances of being born on leap day?
About 1 in
1500.
How many people
were born on leap day?
There are about
187,000 people in the US and 4 million people in the world who were
born on Leap Day.
The rules for
determining a leap year
Most years that can
be divided evenly by 4 are leap years.
Exception: Century years are NOT leap years UNLESS
they can be evenly divided by 400.
When did leap year
originate?
The Gregorian
calendar is closely based on the Julian calendar, which was
introduced by Julius Caesar in
45 BC. The Julian calendar featured a 12-month, 365-day year, with
an intercalary day inserted every fourth year at the end of
February to make an average year of 365.25 days. But because the
length of the solar year is actually 365.242216 days, the Julian
year was too long by .0078 days (11 minutes 14 seconds).
This may not seem
like a lot, but over the course of centuries it added up, until in
the 16th century, the vernal equinox was falling around March 11
instead of March 21. In 1582, Pope Gregory XIII
adjusted the calendar by moving the date ahead by 11 days and by
instituting the exception to the rule for leap years. This new
rule, whereby a century year is a leap year only if divisible by
400, is the sole feature that distinguishes the Gregorian calendar
from the Julian calendar.
Following the
Gregorian reform, the average length of the year was 365.2425 days,
an even closer approximation to the solar year. At this rate, it
will take more than 3,000 years for the Gregorian calendar to gain
one extra day in error.
2008 is a leap
year, which means that it has 366 days instead of the usual 365
days that an ordinary year has. An extra day is added in a leap
year—February 29—which is called an intercalary day or a
leap day.
Why is a Leap Year
Necessary?
Leap years are
added to the calendar to keep it working properly. The 365 days of
the annual calendar are meant to match up with the solar year. A
solar year is the time it takes the Earth to complete its orbit
around the Sun—about one year. But the actual time it takes
for the Earth to travel around the Sun is in fact a little longer
than that—about 365¼ days (365 days, 5 hours, 48 minutes, and
46 seconds, to be precise). So the calendar and the solar year
don't completely match—the calendar year is a touch shorter
than the solar year.
It may not seem
like much of a difference, but after a few years those extra
quarter days in the solar year begin to add up. After four years,
for example, the four extra quarter days would make the calendar
fall behind the solar year by about a day. Over the course of a
century, the difference between the solar year and the calendar
year would become 25 days! Instead of summer beginning in June, for
example, it wouldn't start until nearly a month later, in July. As
every kid looking forward to summer vacation knows—calendar
or no calendar—that's way too late! So every four years a
leap day is added to the calendar to allow it to catch up to the
solar year.
A Quick History
Lesson
The Egyptians were
the first to come up with the idea of adding a leap day once every
four years to keep the calendar in sync with the solar year. Later,
the Romans adopted this solution for their calendar, and they
became the first to designate February 29 as the leap
day.
But Wait! It's Not
Quite that Simple!
The math seems to
work out beautifully when you add an extra day to the calendar
every four years to compensate for the extra quarter of a day in
the solar year. As we said earlier, however, the solar year is
just about 365 ¼ days long—but not exactly! The
exact length of a solar year is actually 11 minutes and 14 seconds
less than 365 ¼ days. That means that even if you add a leap day
every four years, the calendar would still overshoot the solar year
by a little bit—11 minutes and 14 seconds per year. These
minutes and seconds really start to add up: after 128 years, the
calendar would gain an entire extra day. So, the leap year rule,
"add a leap year every four years" was a good rule, but not good
enough!
Calendar
Correction, Part II
To rectify the
situation, the creators of our calendar (the Gregorian
calendar, introduced in 1582) decided to omit leap years three
times every four hundred years. This would shorten the calendar
every so often and rid it of the annual excess of 11 minutes and 14
seconds. So in addition to the rule that a leap year occurs every
four years, a new rule was added: a century year is not a leap year
unless it is evenly divisible by 400. This rule manages to
eliminate three leap years every few hundred years.
It's Smooth
Sailing for the Next 3,300 Years
This ingenious
correction worked beautifully in bringing the calendar and the
solar year in harmony, pretty much eliminating those pesky extra 11
minutes and 14 seconds. Now the calendar year and the solar year
are just about a half a minute off. At that rate, it takes 3,300
years for the calendar year and solar year to diverge by a
day.
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