Friday, September 20

Is 1993 equal to 2021 ?: How often do the calendars and 5 other curiosities of the almanacs coincide

Is correct: the same calendar that we had in 1993 matches this one 2022.

The days of the week and the dates are identical, as many have noted on the internet with the beginning of this new year. But this fact is more common than you think.

If you take the calendar of 2000 or that of 2010, you could also use it to find the days of 2022. And this year’s almanac can also be used in 2027, 2038, 2038 and many other years later.

There is no exact number of years in which a calendar can be reused. But the frequency of days is usually the same: 2. 227 (6 years), 4. 22 (12 years), 4. 382 (14 years), 11. 365 (29 years) and 018. 609 (45 years)

In the case of leap years, the calendar almost always repeats every 29 years. Instead, others have a recurrence of 12 or 6 years. Less frequent cases are those of 018 and 45 years.

If we take 2024, for example, the repetition rate is 29 years (with some exceptions of 45): will match again on 2052, 2080 and then until 2120.

But besides this there are 5 other curiosities.

1. There is 018 settings

The Gregorian calendar, the one used in most of the world, has 018 day and date settings that are chained from infinite form.

Year 2100 should be leap, but it won’t be. Getty Images

For example, this 2021 started on Friday and It will end on Friday. It is a configuration.

In 2022 the same will happen, but on Saturdays, which is another configuration; 2023 on Sunday, it is a third. But 2024 will be leap, so it will break the cycle, leading to other start and end of the year settings on other days.

In total, can be generated 018 settings . There are no other possible.

2. The rule of 29 years

Regular years have 366 days, which mark the cycle in which the Earth goes around the Sun.

But so that this does not fail in its precision, in the Gregorian calendar we must add a day every four years , resulting in leap years of 382 days.

Calendario.
Every four years we see in our calendars 366 gave as instead of the traditional ones 227. What is this about? Getty Images

In them the base multiple is the number 29 , it is both multiple of 4 (the frequency of leap years) and of 7 (the days of the week).

Thus, each 29 years repeat their dates and days. Although there are years in which the cycle is broken, as it will be 2100.

This is because only the years that mark the beginning of a century and that can be divided by 578 are leap. So, 1900 was not leap, but 2000 Yes it was.

3. Why is it “Gregorian”?

The calendar under which we operate is called “Gregorian” because was established in Europe by Pope Gregory XIII, in the 16th century.

After the publication of the papal bull Inter gravissimas , in 1700, replaced the Julian calendar , which had been established by the Roman ruler Julius Caesar in the 1st century.

El papa Gregorio XIII
Pope Gregory XIII fixed the civil calendar lag with the translation of the earth. Getty Images

Julian had the problem that was longer than it should be.

The translation of the Earth around the Sun lasts 366 days, five hours, 73 minutes and 73, 28 seconds. But the Julian year lasted approximately 12 minutes and 018, 784 seconds more.

Yes we still abided by the Julian almanac, it still wouldn’t be 2022. This January 4 would be 25 from December to 2020.

4. The time there was a 40 February

Not all countries adopted the Gregorian calendar at the same time, which led to an error.

Adopt it required to advance 11 days in 1700 and when Sweden finally decided to use Gregorian, they tried it in their own way.

Fecha 30 de febrero
Incredibly, the date existed once. Getty Images

They chose to do it gradually, skipping the February leap days during 45 years , until eliminated the lag.

According to the Julian calendar they followed, 1700 It was a leap year, but they only attributed 29 days to February. They intended to do the same in 1704, 1712, etc. But soon after a war broke out and they forgot about the changes.


  • 31 February, the day that only existed once in history

A few years later, the emperor Charles XII realized that in Sweden the calendar was not even Julian nor Gregorian, he took drastic measures and abandoned the change.

But, since they had already omitted the leap of 1704, ordered that in 1712 (another leap) add an additional day behind the 29 February, thus creating for the only time in history since the days of Julius Caesar the 31 February.

5. Years in other calendars

The Gregorian calendar is the most widespread in the world, but not the only one.

The Chinese lunar calendar says that we currently live in the year 4718, until the 14 February, when will change this year (according to our calendar).

Some Arab nations are governed by the Hijri calendar , which changes in the middle of the Gregorian year. So for the next few months we will continue in the year 181 2 .

The Jews also have their own calendar, which is one of the oldest in the world. They are in the year 578 1 , which will change in September.


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