everybody and we're back this is food for thought
thoughts if it were you season two and this is
your host neogentrics it is 2020 everybody it
is the 6th 7th i forgot what today is of February
and it's three o 'clock in the morning as we
always do today's topic is on leap years because
2020 is in fact a leap year so for the first
time in the last couple of years We get to have
29 days in February, so don't let that throw
you off. If it looks like your calendar doesn't
make sense, no, you didn't buy a faulty calendar.
There is, in fact, an extra day on Saturday.
With that being said, what is a leap year? Let's
start with that, shall we? A leap year, also
known as an intercalinary year or a bisectal
year. It's a calendar year containing an additional
day, or in case of Lunasola calendars, a month.
basically being added to the calendar year to
synchronize with the astronomical or seasonal
year with the way the seasons actually flow.
You know, because seasons and astronomical events
don't repeat in the whole number of days. And
calendars that have the same number of days in
each year drift over time with respect to the
event that the year is supposed to track. You
know, by inserting this extra day... or month
in a year, that drift is automatically corrected
and a year that is not a leap year is called
a common year. It's one of the many things that
exist that a lot of people aren't aware of. Now,
there are two kinds of calendars with that being
said. One is the Gregorian and the original,
the Lunar. Each one has something special about
them that makes them unique and different areas
follow different calendars. And with that being
said, leap years are handled differently in other
countries. I'll cover what a Gregorian calendar
is and what the lunar calendar is in another
podcast. But for now, let's go ahead and talk
about leap years. All right? All right, and we're
back. So let's go ahead and tackle that why do
we have leap years question. First things first,
we need a leap year to keep our modern day Gregorian
calendar in line with the Earth's revolutions
around the sun. It takes Earth approximately
365 .242189 days, or just 365 days to simplify,
and 5 hours and 48 minutes and 45 seconds to
basically circle around the sun. Don't ask me
how they got this number, that's a whole other
podcast for another day. this is what we call
a tropical year and astronomers measure this
from the march equinox however the gregorian
calendar only has 365 days in a year if we didn't
add a leap day on the 29th of february every
four years we would lose almost six hours off
every calendar year uh on its own after only
a hundred years our calendar would be off by
about 24 days you know it's something that they
took into consideration. Leap year rules follow
as such. We add a leap day on February 29th almost
every four years. I say almost because it's not
every single four years. The leap day is an extra
intercalary day. We add it to the shortest month
of the year, typically February. This now begs
the question, how do they calculate the leap
years? In the Gregorian calendar, There are three
criteria that must be taken into account to identify
leap years. The year can be divided by four.
If the year can't be evenly divided by 100, if
the year can be evenly divided by 100, sorry,
it is not a leap year unless the year is also
evenly divisible by 400. Then it is a leap year.
And according to these rules, the years 2000,
2400 are leap years. while 1800, 1900, 2100,
2200, 2300, and 2500 are not leap years. The
year 2000, however, is a special leap year, for
the simple fact that it was unique as it was
the first instance when the third criterion was
used in most parts of the world, since the start
of the tradition started with the Julian calendar
as it transitioned to the Gregorian in 1582,
which, like I said, I'll go into later. Last
but not least, who invented leap years? That
would be the Roman general Julius Caesar. He
introduced the first leap year over 2 ,000 years
ago, but the Julian calendar only had one rule.
Any year evenly divisible by four would be a
leap year, so this formula produced way too many
leap years. Still, it was not corrected until
the introduction of the Gregorian calendar, which
was 1 ,500 years later. Basically the ancient
Roman calendar added an extra month every few
years to maintain correct seasonal changes Which
is really similar to what we call the Chinese
leap year or the lunar year So there's a lot
of stuff that go into this and a lot of facts
that need to be known Now that I covered that,
and I mentioned what the main difference between
leap year and a common year is, we know that
the next leap day is basically February 29, 2020.
Our last leap year was February 29, 2016. Now,
the Gregorian calendar year consists of 52 weeks
and one day. Because of this, January 1st and
31st of a common year are always on the same
day of the week. And the next year begins on
the next day of the week. For instance, the common
year 2021 begins and ends on a Friday. Consequently,
2022 starts and ends on a Saturday, while 2023
starts and ends on a Sunday. Out of every 400
years in the Gregorian calendar, 303 years are
common years. The rest, 97 years, have an intercalary
day, the leap year day, making them 366 days
long. which is, in a way, different from what
we call a tropical year. Common years and other
calendars are split up a little bit differently
as they're set up differently. The Hebrew calendar,
which is the one I mainly use, which is basically
a lunar -solar calendar, has 12 months in a common
year, which we can have anywhere from 353 to
355 days. With the leap years in such a calendar
having 383 to 384 days and 13 months, that means
we get an extra month. The Chinese calendar,
however, is a common year in the Chinese calendar.
In a way saying that, you know, it's also a lunar
calendar as well. They have 12 months, 353 to
355 days. A month in the Chinese common year
corresponds to the cycle of the moon, so from
full moon to full moon. Because of this, a regular
month can have 29 or 30 days. Leap years in the
Chinese calendar, however, have 13 months, so
they add an extra month. Next is the Islamic
calendar. The common years in the Islamic calendar,
which is purely a lunar calendar, have 354 days
divided into 12 months. Some months have 30 days
while others have 29, similar to ours. similar
to the Gregorian calendar anyway. 11 out of 30
years are Islamic leap years. So where the leap
year has 30 days in the last month of the year,
making the Islamic leap year 355 days, different
communities follow different rules about how
to space the leap years in the 30 year cycle.
Last but not least is the Indian calendar. Both
solar and lunar solar calendars with regional
variations are used in Indian or India subcontinent
areas. and the solar calendar, the common years,
again, 365, with 10 leap years of 366 days each
in a cycle of 39 years. However, unlike the Gregorian
calendar, the Indian solar calendar, also known
as the Narayana, I'm pronouncing that the best
I can, there is no fixed rule as to which year
in the cycle will be a leap year. So two kinds
of lunar solar calendars are used in the Indian
system. The Amanta, in which the month runs from
new moon to new moon, and the Paramanta, which
runs from full moon to the next full moon. The
common year in the Amanta calendar is 12 months
long and is 29 days long, on average, and then
the year is 354 days. Seven intercalary months,
called the Adhikmas, are added at different intervals
to the year in a 19 year cycle so go figure now
keep in mind like i mentioned before every calendar
type is different based off of the region that
you're in you know and everyone looks at it differently
this is why i try to make a point of covering
most of the basic information that a lot of people
don't know All right, everybody. The last thing
I want to cover in this talk about lunar year,
as far as the leap year is concerned, is what
is a tropical year and how long does that last?
It's typically called a solar year. A year is
never 365 days long. A tropical year is also
known as a solar year, as an astronomical year,
or an equinoctial year, is basically an average
approximately 365 days, 5 hours, 48 minutes,
and 45 seconds long, or as I mentioned before,
365 .24219 days. A tropical year can be measured
from either the vernal or autumnal equinox. to
the next one, or from summer to winter solstice
to the next one. On the website timeanddate .com,
we calculate on a tropical year from the March
equinox to the next March equinox. And as a result,
our leap day synchronizes with the calendar accordingly.
Although a common year has 365 days, in today's
Gregorian calendar, we add a leap year day nearly
every four years to stay in sync with the tropical
year. So with that being said, without the correct
amount of leap years, our calendar would quickly
become out of sync. This happened to the Julian
calendar, as I mentioned before, because they
had way too many leap years. And eventually they
had to replace it with the Gregorian calendar.
Now keep in mind, it can vary by 30 minutes.
The exact length of a tropical year can vary
up to about half an hour to an hour. For instance,
the tropical year, for example, 2032, will last
longer than 365 days and 6 hours. in 2027 however
will only have last 365 days 5 hours and 39 minutes
each year is different there's websites that
keep track of this on a chart so you can see
what it looked like from 2000 all the way up
to the current 2020 in march now keeping all
of this in mind there's a lot of stuff that comes
with everything that i've mentioned And a lot
of this information you can find on timeanddate
.com. I won't say that I knew this by heart.
But keep in mind that a lot of this information
is available out there for a lot of people to
get. But not everyone knows this. You need to
know about time. You need to know about how it
works. These are important skills people need
to know when they don't know. You need to know
how to read weather. You need to know the time
zone differences. Stuff like this. This stuff
matters. With that being said, I thank you guys
for listening. Enjoy the rest of your day. Again,
this has been Food for Thought. Thoughts if it
were you. I'm your host, Neogentrix. Have a great
rest of your day.