First a note. Not every 4th year is a leap year. Why - we will explain later.
There are 365 days in a typical year. There are 366 days in a leap year - a day more, due to the addition of an additional day under the number 29 to the month of February, as a result of which those born on this day have certain difficulties in celebrating their birthday.
A year is the time during which the planet Earth makes one revolution around the Sun in relation to the stars (visibly measured as the interval between two successive passages of the Sun through the vernal equinox).
A day (or often in everyday speech - a day) is the time during which the Earth makes one revolution around its axis. As you know, there are 24 hours in a day.
It turns out that an even number of days does not fit in a year. There are 365 days, 5 hours, 48 minutes and 45.252 seconds in a year. If the year is taken equal to 365 days, then it turns out that the Earth in its orbital motion will not "reach" the point at which the circle "closes", i.e. before it, it is necessary to fly in orbit for another 5 hours, 48 minutes and 45.252 seconds. These extra about 6 hours over 4 years will just come together in one additional day, which was introduced into the calendar to eliminate the backlog, having received every 4th year leap- a day longer. He did it on January 1, 45 BC. NS. Roman dictator Guy Julius Caesar, and the calendar has since been called Julian... In fairness, I must say that Julius Caesar only introduced new calendar, but it was, of course, astronomers who calculated and proposed it.
The Russian word "leap" comes from the Latin expression "bis sextus" - "second sixth". The ancient Romans counted the days of the month until the beginning of the next month. So the day of February 24 was the sixth until the beginning of March. In a leap year between February 24 and February 25, an additional, second (bis sextus) sixth day was inserted. Later, this day began to increase towards the end of the month, February 29.
So, according to the Julian calendar, every 4th year is a leap year.
But it is easy to see that 5 hours, 48 minutes and 45.252 seconds is not exactly 6 hours (11 minutes 14 seconds are missing). Of these 11 minutes and 14 seconds, one more extra day will "run over" in 128 years. This was noticed from astronomical observations on the displacement of the day of the vernal equinox, relative to which the church holidays especially Easter. By the 16th century, the lag was 10 days (today it is already 13 days). To eliminate him, Pope Gregory XIII carried out a calendar reform ( Gregorian calendar), according to which not every 4th year was a leap year. The years were not leap years, multiples of one hundred, that is, ending with two zeros. The only exceptions were years, divisible by 400.
So, leap years are years: 1) divisible by 4, but not by 100 (for example, 2016, 2020, 2024),
Note that the Russian Orthodox Church refused to switch to the Gregorian calendar and lives according to the old, Julian calendar, which is 13 days behind the Gregorian. If the church continues to refuse to switch to the generally accepted Gregorian calendar, then in a few hundred years the shift will become such that, for example, Christmas will be celebrated in the summer.
sharky:
03/25/2013 at 16:04
and why is 1900 not a leap year? A leap year occurs every 4 years, i.e. if it is divisible by 4, it is a leap year. And no more divisions by 100 or 400 are needed.
It is normal to ask questions, but before you assert something, study the materiel. The Earth makes a revolution around the sun in 365 days 5 hours 48 minutes 46 seconds. As you can see, the remainder is not exactly 6 hours, but 11 minutes 14 seconds less. This means that by making a leap year we add extra time. Somewhere over 128 years, extra days accumulate. Therefore, every 128 years in one of the 4-year cycles, a leap year does not need to be done in order to get rid of these extra days. But to keep it simple, leap years are not made every 100th year. Do you get the idea? Good. But how then to proceed, because an extra day is added every 128 years, and we cut it down every 100 years? Yes, we cut off more than we should, and this needs to be returned sometime.
If the first paragraph is clear and still interesting, then read on, but it will be more difficult.
So for 100 years, 100/128 = 25/32 days of extra time runs up (this is 18 hours 45 minutes). We do not make a leap year, that is, we subtract one day: we get 25 / 32-32 / 32 = -7/32 days (this is 5 hours 15 minutes), that is, we subtract the excess. After four cycles of 100 years (after 400 years), we will subtract the extra 4 * (- 7/32) = - 28/32 days (this is minus 21 hours). For the 400th year, we make a leap year, that is, we add a day (24 hours): -28/32 + 32/32 = 4/32 = 1/8 (this is 3 hours).
We make every 4 year a leap year, but at the same time every 100 year is not a leap year, and at the same time every 400 year is a leap year, but still every 400 years an extra 3 hours are added. After 8 cycles of 400 years each, that is, after 3200 years, an extra 24 hours will accumulate, that is, one day. Then one more is added required condition: every 3200th year must not be a leap year. 3200 years can be rounded up to 4000, but then again you will have to play with added or truncated days.
3200 years have not passed, so this condition, if it is made like that, is not yet talked about. But 400 years have passed since the adoption of the Gregorian calendar.
Years divisible by 400 are always leap years (so far for today), other years divisible by 100 are not leap years, other years divisible by 4 are leap years.
The calculation I have given shows that, in the current state, an error in one day will accumulate over 3200 years, but here's what Wikipedia writes about it:
“An error of one day compared to the year of the equinoxes in the Gregorian calendar will accumulate in about 10,000 years (in the Julian - in about 128 years). A frequently occurring estimate leading to a value of the order of 3000 years is obtained if one does not take into account that the number of days in a tropical year changes over time and, in addition, the ratio between the lengths of the seasons changes. " From the same Wikipedia, the formula for the length of a year in days with fractions gives a good picture:
365,2425=365+0,25-0,01+0,0025=265+1/4-1/100+1/400
The year 1900 was not a leap year, but 2000 was, and it was special, because such a leap year happens once every 400 years.
Leap year, or it is also called the word "leap", causes a lot of rumors and superstitions, which boil down mainly to the fact that this year is unhappy and promises only negative events. In this article, we will talk about how fair these opinions are.
A bit of history
The word "leap" came to us from the Latin language, that is, it is of ancient origin, and its literal translation sounds like "the second sixth".
According to the Julian month, the Earth completes its circle in 365.25 days, with all this every day shifted by 6 hours. Such an error could well confuse ancient men, and in order to avoid this, it was decided that after every fourth year, one more day will be added to the annual circle. Accordingly, this year will include 366 days, and they will be added in the shortest month - February, it will consist of 29 days. To distinguish it, it was called a leap.
On Ancient Rus, in turn, there were many legends about the emergence of leap years, and each of them, even then, was perceived as necessarily unhappy. Legends about the arrival of the new calendar and the leap year in it in Russia were reflected in the Holy Calendar as well. So, on February 29, they are dedicated to the memory of St. Kasyan, and the people call him Kasyan's Day. Several legends and apocryphas (stories that are not recognized by the church as confirmed and consistent with what we know about God) are dedicated to this day. But it sheds light on the origin of the bad reputation of leap years.
According to this legend, Kasyan appears to the common people not as a man, but as an angel, and a fallen one, who was once tempted by Satan, as a result of which he fell away from God. However, in the future, he realized how wrong he was, repented and prayed to the Creator for mercy. Taking pity on the traitor, God, before taking him back, assigned his angel to him. The celestial dweller put Kasyan in shackles and, by order from above, beat him in the forehead with a metal hammer for admonition for 3 years, and released him on the fourth.
The second legend about Kasyan
According to the second legend Kasyan- this is a person, and Kasyanov's day is the date of his name day. However, according to the legend, that man systematically revels in death for three years in a row, but on the fourth he came to his senses, brought repentance, gave up his addiction, turned to repentance and became a saint - he acquired the Holy Spirit. Therefore, the people believed, it befits them to celebrate their day so rarely - only on February 29.
The third legend about Kasyan
This legend is dedicated to Saint Kasyan who travels the earth and Nicholas the Wonderworker, well-known to Christians. And now they meet a peasant along the way. He asked them for help as his wagon got stuck in the mud. Kasyan responded to this that he was afraid to spoil his clean robe, and Nikolai, not afraid of dirt, immediately helped. The saints returned to the Kingdom of God, and the Creator noticed that Nicholas's robe was stained and asked him what it was connected with.
The saint told him what happened on the way. Then the Lord noticed that Kasyan had clean vestments, and asked the question: did they not travel together? Kasyan replied that he was afraid to get his clothes dirty. God enlightened that Kosma was disingenuous, and arranged in such a way that his name day was celebrated with him once every 4 years. And the namesake of Nicholas for his meekness - twice in 365 days.
Anyway whatever it is, the leap was recognized as bad. Therefore, the Russian superstitious people tried to somehow protect themselves from this day.
- He strove to complete all important cases by the 29th of February.
- Some did not dare to leave the house.
- On February 29, if the sun came out, it was called the Eye of Kasyan or Kasyan's eye. Then they tried not to fall under the sun, so that the saint would not ... jinx them! And he did not bring on the poor man suffering and disease.
As in ancient times, in today's world you often come across superstitions and omens that are not with better side define the leap years of the 21st century. We will list some of them:
Why Leap Years Are Bad
This attitude is quite understandable: the appearance of the 29th day in February characterizes the whole year differently from others, psychologically distinguishes it from the others. This can be meaningful for a person who is not confident in their abilities. It will be much easier for him, referring to this special period, to abandon something new than to expend energy for self-development or starting some kind of business.
For the same reason, it will be easier not to get pregnant, so as not to give birth later, because the fear increases that childbirth will be difficult, the baby may be born painful. And if not, then suddenly his life will be bleak or difficult.
Our inventive people discern and the threat in the very name of the leap, saying that it "harasses" people, in other words, takes them away, leads to death. Therefore, the holiday is greeted with caution (or, conversely, on a special scale - you never know who will die ...). This is a very common opinion that tries to penetrate statistics. It is becoming accepted to believe that the mortality rate increases every 4th year. At the same time, the statistics themselves do not confirm these data in any way.
Mushrooms cannot be collected either, and even more so they cannot be eaten or sold to people. No, not so as not to get poisoned, but so that with the "bad soil" a person does not get "what is bad".
It is believed that a leap year leads to cataclysms in nature and all kinds of disasters: drought, floods, fires.
What years are leap years
In the last century, as well as in the present, such calendar periods were also terrifying. A list of them can be seen in the image or found on the Internet. Also, 2000, the same millennium, was in its turn a leap year, opening a whole millennium.
Despite the fact that with the development of technology, information has become more accessible and there is an opportunity to learn more and broaden horizons, getting rid of primitive fears, many continue to anxiously expect a leap, internally setting themselves up for problems and troubles, and when they come (if they come), it is perceived doomed: well, after all, a leap ... An extra day in February. Deadly!
There are special calendars that indicate when exactly the leap occurs. It is enough to carefully look at the table and find (or not find) the actual numbers there. It is enough to find out at least one leap year, after which it will be possible to calculate them independently through elementary arithmetic. Let's say you are interested in leap years in the 21st century. Find the calendar and view it. After learning that 2016 is a leap year, it's easy to understand that the next one will come in 2020.
According to statistics, very few of all disasters and troubles fall on leap days. The superstitions that exist in our days can be interpreted by the fact that people, who closely followed the misfortunes and troubles that occurred on leap years, reported what was happening with an exaggerated meaning only because of the unflattering reputation of the latter. Individuals who greatly trust superstitions about leap years would like to wish to pay more attention to positive events and changes. And then, perhaps, there will be a list of good and joyful signs restoring the reputation of leap years.
sharky:
03/25/2013 at 16:04
and why is 1900 not a leap year? A leap year occurs every 4 years, i.e. if it is divisible by 4, it is a leap year. And no more divisions by 100 or 400 are needed.
It is normal to ask questions, but before you assert something, study the materiel. The Earth makes a revolution around the sun in 365 days 5 hours 48 minutes 46 seconds. As you can see, the remainder is not exactly 6 hours, but 11 minutes 14 seconds less. This means that by making a leap year we add extra time. Somewhere over 128 years, extra days accumulate. Therefore, every 128 years in one of the 4-year cycles, a leap year does not need to be done in order to get rid of these extra days. But to keep it simple, leap years are not made every 100th year. Do you get the idea? Good. But how then to proceed, because an extra day is added every 128 years, and we cut it down every 100 years? Yes, we cut off more than we should, and this needs to be returned sometime.
If the first paragraph is clear and still interesting, then read on, but it will be more difficult.
So for 100 years, 100/128 = 25/32 days of extra time runs up (this is 18 hours 45 minutes). We do not make a leap year, that is, we subtract one day: we get 25 / 32-32 / 32 = -7/32 days (this is 5 hours 15 minutes), that is, we subtract the excess. After four cycles of 100 years (after 400 years), we will subtract the extra 4 * (- 7/32) = - 28/32 days (this is minus 21 hours). For the 400th year, we make a leap year, that is, we add a day (24 hours): -28/32 + 32/32 = 4/32 = 1/8 (this is 3 hours).
We make every 4 year a leap year, but at the same time every 100 year is not a leap year, and at the same time every 400 year is a leap year, but still every 400 years an extra 3 hours are added. After 8 cycles of 400 years each, that is, after 3200 years, an extra 24 hours will accumulate, that is, one day. Then another prerequisite is added: every 3200th year should not be a leap year. 3200 years can be rounded up to 4000, but then again you will have to play with added or truncated days.
3200 years have not passed, so this condition, if it is made like that, is not yet talked about. But 400 years have passed since the adoption of the Gregorian calendar.
Years divisible by 400 are always leap years (so far for today), other years divisible by 100 are not leap years, other years divisible by 4 are leap years.
The calculation I have given shows that, in the current state, an error in one day will accumulate over 3200 years, but here's what Wikipedia writes about it:
“An error of one day compared to the year of the equinoxes in the Gregorian calendar will accumulate in about 10,000 years (in the Julian - in about 128 years). A frequently occurring estimate leading to a value of the order of 3000 years is obtained if one does not take into account that the number of days in a tropical year changes over time and, in addition, the ratio between the lengths of the seasons changes. " From the same Wikipedia, the formula for the length of a year in days with fractions gives a good picture:
365,2425=365+0,25-0,01+0,0025=265+1/4-1/100+1/400
The year 1900 was not a leap year, but 2000 was, and it was special, because such a leap year happens once every 400 years.
Leap year (Latin bis sextus - "second sixth") - a year in the Julian and Gregorian calendars, the duration of which is 366 days - one day longer than the duration of a regular, non-leap year. In the Julian calendar, a leap year is every fourth year, in the Gregorian calendar there are exceptions to this rule.
A year is a conventional unit of time, which historically meant a single cycle of seasons (spring, summer, autumn, winter). In most countries, the calendar length of the year is 365 or 366 days. Currently, the year is also used as a temporal characteristic of the revolution of planets around stars in planetary systems, in particular the Earth around the Sun.
The calendar year in the Gregorian and Julian calendars is 365 days in non-leap years, and 366 days in leap years. The average length of the year is 365.2425 days for the Gregorian and 365.25 days for the Julian calendars.
The calendar year in the Islamic calendar contains 353, 354 or 355 days - 12 lunar months... The average length of a year is 354.37 days, which is less than a tropical year, and therefore Muslim holidays "wander" according to the seasons.
The calendar year in the Hebrew calendar contains 353, 354, or 355 days in a simple year and 383, 384, or 385 days in a leap year. The average length of the year is 365.2468 days, which is close to the tropical year.
The duration of the tropical year (the time between the two vernal equinoxes) is 365 days 5 hours 48 minutes 46 seconds. The difference in the length of the tropical year and the average Julian calendar year (365.25 days) is 11 minutes 14 seconds. These 11 minutes and 14 seconds add up to one day in approximately 128 years.
Over the centuries, a shift in the day of the vernal equinox, associated with church holidays, was noticed. TO XVI century the vernal equinox came about 10 days earlier than March 21, which is used to determine the day of Easter.
To compensate for the accumulated error and avoid such a shift in the future, in 1582 Pope Gregory XIII carried out a calendar reform. To better match the average calendar year with the solar year, it was decided to change the leap year rule. The year remained a leap year, the number of which is a multiple of four, but an exception was made for those that were multiples of 100. From now on, such years were leap years only when they were also divisible by 400.
In other words, a year is a leap year in two cases: either it is a multiple of 4, but not a multiple of 100, or a multiple of 400. A year is not a leap year, if it is not a multiple of 4, or it is a multiple of 100, but not a multiple of 400.
The last years of centuries ending in two zeros are not leap years in three cases out of four. So, years 1700, 1800 and 1900 are not leap years, since they are multiples of 100 and not multiples of 400. Years 1600 and 2000 are leap years, since they are multiples of 400. Years 2100, 2200 and 2300 are non-leap years. In leap years, an additional day is introduced - February 29. The Catholic world lives according to the Julian calendar. Unlike the Julian calendar, the Gregorian calendar takes into account only one object - the Sun.
Now we live according to the Julian calendar ( new style), before the revolution they lived according to the Gregorian ( old style). The difference between the old and new styles was 11 days in the 18th century, 12 days in the 19th century, and XXI centuries- 13 days. In the XXII century, this difference will be already 14 days. The Gregorian calendar was introduced under Soviet power on February 14, 1918 (after January 31, it was not February 1, but immediately the 14th). The last leap year was, the next will be.
1996, 1992, 1988, 1984, 1980, 1976, 1972, 1968, 1964, 1960, 1956, 1952, 1948, 1944, 1940, 1936, 1932, 1928, 1924, 1920, 1916, 1912, 1908, 1904, Gregorian 1900 is a common year; Julian is a leap year. 1896.
Note: For most computer and mobile systems valid dates are from December 13, 1901, 20:45:54 GMT to January 19, 2038, 03:14:07 GMT. (These dates correspond to the minimum and maximum value of a 32-bit signed integer.) For Windows, valid dates are 01-01-1970 through 01.19-2038.
